Sample records for stimulating bone formation
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Strontium ranelate: a novel mode of action leading to renewed bone quality.
Ammann, Patrick
2005-01-01
Various bone resorption inhibitors and bone stimulators have been shown to decrease the risk of osteoporotic fractures. However, there is still a need for agents promoting bone formation by inducing positive uncoupling between bone formation and bone resorption. In vitro studies have suggested that strontium ranelate enhances osteoblast cell replication and activity. Simultaneously, strontium ranelate dose-dependently inhibits osteoclast activity. In vivo studies indicate that strontium ranelate stimulates bone formation and inhibits bone resorption and prevents bone loss and/or promotes bone gain. This positive uncoupling between bone formation and bone resorption results in bone gain and improvement in bone geometry and microarchitecture, without affecting the intrinsic bone tissue quality. Thus, all the determinants of bone strength are positively influenced. In conclusion, strontium ranelate, a new treatment of postmenopausal osteoporosis, acts through an innovative mode of action, both stimulating bone formation and inhibiting bone resorption, resulting in the rebalancing of bone turnover in favor of bone formation. Strontium ranelate increases bone mass while preserving the bone mineralization process, resulting in improvement in bone strength and bone quality.
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Selective inhibitors of the osteoblast proteasome stimulate bone formation in vivo and in vitro
Garrett, I.R.; Chen, D.; Gutierrez, G.; Zhao, M.; Escobedo, A.; Rossini, G.; Harris, S.E.; Gallwitz, W.; Kim, K.B.; Hu, S.; Crews, C.M.; Mundy, G.R.
2003-01-01
We have found that the ubiquitin-proteasome pathway exerts exquisite control of osteoblast differentiation and bone formation in vitro and in vivo in rodents. Structurally different inhibitors that bind to specific catalytic β subunits of the 20S proteasome stimulated bone formation in bone organ cultures in concentrations as low as 10 nM. When administered systemically to mice, the proteasome inhibitors epoxomicin and proteasome inhibitor–1 increased bone volume and bone formation rates over 70% after only 5 days of treatment. Since the ubiquitin-proteasome pathway has been shown to modulate expression of the Drosophila homologue of the bone morphogenetic protein-2 and -4 (BMP-2 and BMP-4) genes, we examined the effects of noggin, an endogenous inhibitor of BMP-2 and BMP-4 on bone formation stimulated by these compounds and found that it was abrogated. These compounds increased BMP-2 but not BMP-4 or BMP-6 mRNA expression in osteoblastic cells, suggesting that BMP-2 was responsible for the observed bone formation that was inhibited by noggin. We show proteasome inhibitors regulate BMP-2 gene expression at least in part through inhibiting the proteolytic processing of Gli3 protein. Our results suggest that the ubiquitin-proteasome machinery regulates osteoblast differentiation and bone formation and that inhibition of specific components of this system may be useful therapeutically in common diseases of bone loss. PMID:12782679
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Yan, Haoran; Liu, Xia; Zhu, Minghua; Luo, Guilin; Sun, Tao; Peng, Qiang; Zeng, Yi; Chen, Taijun; Wang, Yingying; Liu, Keliang; Feng, Bo; Weng, Jie; Wang, Jianxin
2016-01-01
In this study, a multilayer coating technology would be adopted to prepare a porous composite scaffold and the growth factor release and ultrasound techniques were introduced into bone tissue engineering to finally solve the problems of vascularization and bone formation in the scaffold whilst the designed multilayer composite with gradient degradation characteristics in the space was used to match the new bone growth process better. The results of animal experiments showed that the use of low intensity pulsed ultrasound (LIPUS) combined with growth factors demonstrated excellent capabilities and advantages in both vascularization and new bone formation in bone tissue engineering. The degradation of the used scaffold materials could match new bone formation very well. The results also showed that only RGD-promoted cell adhesion was insufficient to satisfy the needs of new bone formation while growth factors and LIPUS stimulation were the key factors in new bone formation. © 2015 Wiley Periodicals, Inc.
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Sims, Natalie A
2016-10-01
Bone renews itself and changes shape throughout life to account for the changing needs of the body; this requires co-ordinated activities of bone resorbing cells (osteoclasts), bone forming cells (osteoblasts) and bone's internal cellular network (osteocytes). This review focuses on paracrine signaling by the IL-6 family of cytokines between bone cells, bone marrow, and skeletal muscle in normal physiology and in pathological states where their levels may be locally or systemically elevated. These functions include the support of osteoclast formation by osteoblast lineage cells in response to interleukin 6 (IL-6), interleukin 11 (IL-11), oncostatin M (OSM) and cardiotrophin 1 (CT-1). In addition it will discuss how bone-resorbing osteoclasts promote osteoblast activity by secreting CT-1, which acts as a "coupling factor" on osteocytes, osteoblasts, and their precursors to promote bone formation. OSM, produced by osteoblast lineage cells and macrophages, stimulates bone formation via osteocytes. IL-6 family cytokines also mediate actions of other bone formation stimuli like parathyroid hormone (PTH) and mechanical loading. CT-1, OSM and LIF suppress marrow adipogenesis by shifting commitment of pluripotent precursors towards osteoblast differentiation. Ciliary neurotrophic factor (CNTF) is released as a myokine from skeletal muscle and suppresses osteoblast differentiation and bone formation on the periosteum (outer bone surface in apposition to muscle). Finally, IL-6 acts directly on marrow-derived osteoclasts to stimulate release of "osteotransmitters" that act through the cortical osteocyte network to stimulate bone formation on the periosteum. Each will be discussed as illustrations of how the extended family of IL-6 cytokines acts within the skeleton in physiology and may be altered in pathological conditions or by targeted therapies. Copyright © 2016 Elsevier Ltd. All rights reserved.
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Yeh, Lee-Chuan C; Ma, Xiuye; Ford, Jeffery J; Adamo, Martin L; Lee, John C
2013-08-01
Bone morphogenetic proteins (BMPs) promote osteoblast differentiation and bone formation in vitro and in vivo. BMPs canonically signal through Smad transcription factors, but BMPs may activate signaling pathways traditionally stimulated by growth factor tyrosine kinase receptors. Of these, the mTOR pathway has received considerable attention because BMPs activate P70S6K, a downstream effector of mTOR, suggesting that BMP-induced osteogenesis is mediated by mTOR activation. However, contradictory effects of the mTOR inhibitor rapamycin (RAPA) on bone formation have been reported. Since bone formation is thought to be inversely related to lipid accumulation and mTOR is also important for lipid synthesis, we postulated that BMP-7 may stimulate lipogenic enzyme expression in a RAPA-sensitive mechanism. To test this hypothesis, we determined the effects of RAPA on BMP-7-stimulated expression of osteogenic and lipogenic markers in cultured fetal rat calvarial cells. Our study showed that BMP-7 promoted the expression of osteogenic and lipogenic markers. The effect of BMP-7 on osteogenic markers was greater in magnitude than on lipogenic markers and was temporally more sustained. RAPA inhibited basal and BMP-7-stimulated osteogenic and lipogenic marker expression and bone nodule mineralization. The acetyl CoA carboxylase inhibitor TOFA stimulated the expression of osteoblast differentiation markers, whereas palmitate suppressed their expression. We speculate that the BMP-7-stimulated adipogenesis is part of the normal anabolic response to BMPs, but that inappropriate activation of the lipid biosynthetic pathway by mTOR could have deleterious effects on bone formation and could explain paradoxical effects of RAPA to promote bone formation. Copyright © 2013 Wiley Periodicals, Inc.
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IFN-γ stimulates osteoclast formation and bone loss in vivo via antigen-driven T cell activation
Gao, Yuhao; Grassi, Francesco; Ryan, Michaela Robbie; Terauchi, Masakazu; Page, Karen; Yang, Xiaoying; Weitzmann, M. Neale; Pacifici, Roberto
2006-01-01
T cell–produced cytokines play a pivotal role in the bone loss caused by inflammation, infection, and estrogen deficiency. IFN-γ is a major product of activated T helper cells that can function as a pro- or antiresorptive cytokine, but the reason why IFN-γ has variable effects in bone is unknown. Here we show that IFN-γ blunts osteoclast formation through direct targeting of osteoclast precursors but indirectly stimulates osteoclast formation and promotes bone resorption by stimulating antigen-dependent T cell activation and T cell secretion of the osteoclastogenic factors RANKL and TNF-α. Analysis of the in vivo effects of IFN-γ in 3 mouse models of bone loss — ovariectomy, LPS injection, and inflammation via silencing of TGF-β signaling in T cells — reveals that the net effect of IFN-γ in these conditions is that of stimulating bone resorption and bone loss. In summary, IFN-γ has both direct anti-osteoclastogenic and indirect pro-osteoclastogenic properties in vivo. Under conditions of estrogen deficiency, infection, and inflammation, the net balance of these 2 opposing forces is biased toward bone resorption. Inhibition of IFN-γ signaling may thus represent a novel strategy to simultaneously reduce inflammation and bone loss in common forms of osteoporosis. PMID:17173138
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Bone modeling and remodeling: potential as therapeutic targets for the treatment of osteoporosis.
Langdahl, Bente; Ferrari, Serge; Dempster, David W
2016-12-01
The adult skeleton is renewed by remodeling throughout life. Bone remodeling is a process where osteoclasts and osteoblasts work sequentially in the same bone remodeling unit. After the attainment of peak bone mass, bone remodeling is balanced and bone mass is stable for one or two decades until age-related bone loss begins. Age-related bone loss is caused by increases in resorptive activity and reduced bone formation. The relative importance of cortical remodeling increases with age as cancellous bone is lost and remodeling activity in both compartments increases. Bone modeling describes the process whereby bones are shaped or reshaped by the independent action of osteoblast and osteoclasts. The activities of osteoblasts and osteoclasts are not necessarily coupled anatomically or temporally. Bone modeling defines skeletal development and growth but continues throughout life. Modeling-based bone formation contributes to the periosteal expansion, just as remodeling-based resorption is responsible for the medullary expansion seen at the long bones with aging. Existing and upcoming treatments affect remodeling as well as modeling. Teriparatide stimulates bone formation, 70% of which is remodeling based and 20-30% is modeling based. The vast majority of modeling represents overflow from remodeling units rather than de novo modeling. Denosumab inhibits bone remodeling but is permissive for modeling at cortex. Odanacatib inhibits bone resorption by inhibiting cathepsin K activity, whereas modeling-based bone formation is stimulated at periosteal surfaces. Inhibition of sclerostin stimulates bone formation and histomorphometric analysis demonstrated that bone formation is predominantly modeling based. The bone-mass response to some osteoporosis treatments in humans certainly suggests that nonremodeling mechanisms contribute to this response and bone modeling may be such a mechanism. To date, this has only been demonstrated for teriparatide, however, it is clear that rediscovering a phenomenon that was first observed more half a century ago will have an important impact on our understanding of how new antifracture treatments work.
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Cipitria, A; Wagermaier, W; Zaslansky, P; Schell, H; Reichert, J C; Fratzl, P; Hutmacher, D W; Duda, G N
2015-09-01
Scaffold architecture guides bone formation. However, in critical-sized long bone defects additional BMP-mediated osteogenic stimulation is needed to form clinically relevant volumes of new bone. The hierarchical structure of bone determines its mechanical properties. Yet, the micro- and nanostructure of BMP-mediated fast-forming bone has not been compared with slower regenerating bone without BMP. We investigated the combined effects of scaffold architecture (physical cue) and BMP stimulation (biological cue) on bone regeneration. It was hypothesized that a structured scaffold directs tissue organization through structural guidance and load transfer, while BMP stimulation accelerates bone formation without altering the microstructure at different length scales. BMP-loaded medical grade polycaprolactone-tricalcium phosphate scaffolds were implanted in 30mm tibial defects in sheep. BMP-mediated bone formation after 3 and 12 months was compared with slower bone formation with a scaffold alone after 12 months. A multiscale analysis based on microcomputed tomography, histology, polarized light microscopy, backscattered electron microscopy, small angle X-ray scattering and nanoindentation was used to characterize bone volume, collagen fiber orientation, mineral particle thickness and orientation, and local mechanical properties. Despite different observed kinetics in bone formation, similar structural properties on a microscopic and sub-micron level seem to emerge in both BMP-treated and scaffold only groups. The guiding effect of the scaffold architecture is illustrated through structural differences in bone across different regions. In the vicinity of the scaffold increased tissue organization is observed at 3 months. Loading along the long bone axis transferred through the scaffold defines bone micro- and nanostructure after 12 months. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
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Effects of Vitamin K2 on the Development of Osteopenia in Rats as the Models of Osteoporosis
Takeda, Tsuyoshi; Sato, Yoshihiro
2006-01-01
Vitamin K2 is widely used for the treatment of osteoporosis in Japan. To understand the effects of vitamin K2 on bone mass and bone metabolism, we reviewed its effects on the development of osteopenia in rats, which characterizes models of osteoporosis. Vitamin K2 was found to attenuate the increase in bone resorption and/or maintain bone formation, reduce bone loss, protect against the loss of trabecular bone mass and its connectivity, and prevent the decrease in strength of the long bone in ovariectomized rats. However, combined treatment of bisphosphonates and vitamin K2 had an additive effect in preventing the deterioration of the trabecular bone architecture in ovariectomized rats, while the combined treatment of raloxifene and vitamin K2 improved the bone strength of the femoral neck. The use of vitamin K2 alone suppressed the increase in trabecular bone turnover and endocortical bone resorption, which attenuated the development of cancellous and cortical osteopenia in orchidectomized rats. In addition, vitamin K2 inhibited the decrease in bone formation in prednisolone-treated rats, thereby preventing cancellous and cortical osteopenia. In sciatic neurectomized rats, vitamin K2 suppressed endocortical bone resorption and stimulated bone formation, delaying the reduction of the trabecular thickness and retarding the development of cortical osteopenia. Vitamin K2 also prevented the acceleration of bone resorption and the reduction in bone formation in tail-suspended rats, which counteracted cancellous bone loss. Concomitant use of vitamin K2 with a bisphosphonate ameliorated the suppression of bone formation and more effectively prevented cancellous bone loss in tail-suspended rats. Vitamin K2 stimulated renal calcium reabsorption, retarded the increase in serum parathyroid hormone levels, and attenuated cortical bone loss primarily by suppressing bone resorption in calcium-deficient rats while maintaining the strength of the long bone in rats with magnesium deficiency. These findings suggest that vitamin K2 may not only stimulate bone formation, but may also suppress bone resorption. Thus, vitamin K2 could regulate bone metabolism in rats, which represented the various models of osteoporosis. However, the effects of vitamin K2 on bone mass and bone metabolism seem to be modest. PMID:16642543
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Kaempferol stimulates bone sialoprotein gene transcription and new bone formation.
Yang, Li; Takai, Hideki; Utsunomiya, Tadahiko; Li, Xinyue; Li, Zhengyang; Wang, Zhitao; Wang, Shuang; Sasaki, Yoko; Yamamoto, Hirotsugu; Ogata, Yorimasa
2010-08-15
Kaempferol is a typical flavonol-type flavonoid that is present in a variety of vegetables and fruits, and has a protective effect on postmenopausal bone loss. Bone sialoprotein (BSP) is thought to function in the initial mineralization of bone and could be crucial for osteoblast differentiation, bone matrix mineralization and tumor metastasis. In the present study we investigated the regulation of BSP transcription by kaempferol in rat osteoblast-like UMR106 cells, and the effect of kaempferol on new bone formation. Kaempferol (5 microM) increased BSP and Osterix mRNA levels at 12 h and up-regulated Runx2 mRNA expression at 6 h. Kaempferol increased luciferase activity of the construct pLUC3, which including the promoter sequence between nucleotides -116 to +60. Transcriptional stimulation by kaempferol abrogated in constructs included 2 bp mutations in the inverted CCAAT, CRE, and FRE elements. Gel shift analyses showed that kaempferol increased nuclear protein binding to CRE and FRE elements, whereas the CCAAT-protein complex did not change after kaempferol stimulation. Twelve daily injections of 5 microM kaempferol directly into the periosteum of parietal bones of newborn rats increased new bone formation. These data suggest that kaempferol increased BSP gene transcription mediated through inverted CCAAT, CRE, and FRE elements in the rat BSP gene promoter, and could induce osteoblast activities in the early stage of bone formation. (c) 2010 Wiley-Liss, Inc.
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Tang, De-Zhi; Hou, Wei; Zhou, Quan; Zhang, Minjie; Holz, Jonathan; Sheu, Tzong-Jen; Li, Tian-Fang; Cheng, Shao-Dan; Shi, Qi; Harris, Stephen E; Chen, Di; Wang, Yong-Jun
2010-01-01
Osteoporosis is defined as reduced bone mineral density with a high risk of fragile fracture. Current available treatment regimens include antiresorptive drugs such as estrogen receptor analogues and bisphosphates and anabolic agents such as parathyroid hormone (PTH). However, neither option is completely satisfactory because of adverse effects. It is thus highly desirable to identify novel anabolic agents to improve future osteoporosis treatment. Osthole, a coumarin-like derivative extracted from Chinese herbs, has been shown to stimulate osteoblast proliferation and differentiation, but its effect on bone formation in vivo and underlying mechanism remain unknown. In this study, we found that local injection of Osthole significantly increased new bone formation on the surface of mouse calvaria. Ovariectomy caused evident bone loss in rats, whereas Osthole largely prevented such loss, as shown by improved bone microarchitecture, histomorphometric parameters, and biomechanical properties. In vitro studies demonstrated that Osthole activated Wnt/β-catenin signaling, increased Bmp2 expression, and stimulated osteoblast differentiation. Targeted deletion of the β-catenin and Bmp2 genes abolished the stimulatory effect of Osthole on osteoblast differentiation. Since deletion of the Bmp2 gene did not affect Osthole-induced β-catenin expression and the deletion of the β-catenin gene inhibited Osthole-regulated Bmp2 expression in osteoblasts, we propose that Osthole acts through β-catenin–BMP signaling to promote osteoblast differentiation. Our findings demonstrate that Osthole could be a potential anabolic agent to stimulate bone formation and prevent estrogen deficiency–induced bone loss. © 2010 American Society for Bone and Mineral Research. PMID:20200936
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Pederson, Larry; Ruan, Ming; Westendorf, Jennifer J.; Khosla, Sundeep; Oursler, Merry Jo
2008-01-01
Under most conditions, resorbed bone is nearly precisely replaced in location and amount by new bone. Thus, it has long been recognized that bone loss through osteoclast-mediated bone resorption and bone replacement through osteoblast-mediated bone formation are tightly coupled processes. Abundant data conclusively demonstrate that osteoblasts direct osteoclast differentiation. Key questions remain, however, as to how osteoblasts are recruited to the resorption site and how the amount of bone produced is so precisely controlled. We hypothesized that osteoclasts play a crucial role in the promotion of bone formation. We found that osteoclast conditioned medium stimulates human mesenchymal stem (hMS) cell migration and differentiation toward the osteoblast lineage as measured by mineralized nodule formation in vitro. We identified candidate osteoclast-derived coupling factors using the Affymetrix microarray. We observed significant induction of sphingosine kinase 1 (SPHK1), which catalyzes the phosphorylation of sphingosine to form sphingosine 1-phosphate (S1P), in mature multinucleated osteoclasts as compared with preosteoclasts. S1P induces osteoblast precursor recruitment and promotes mature cell survival. Wnt10b and BMP6 also were significantly increased in mature osteoclasts, whereas sclerostin levels decreased during differentiation. Stimulation of hMS cell nodule formation by osteoclast conditioned media was attenuated by the Wnt antagonist Dkk1, a BMP6-neutralizing antibody, and by a S1P antagonist. BMP6 antibodies and the S1P antagonist, but not Dkk1, reduced osteoclast conditioned media-induced hMS chemokinesis. In summary, our findings indicate that osteoclasts may recruit osteoprogenitors to the site of bone remodeling through SIP and BMP6 and stimulate bone formation through increased activation of Wnt/BMP pathways. PMID:19075223
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Zhou, Feng; Shen, Yi; Liu, Bo
Bone is a rigid yet dynamic organ, and this dynamism is mediated by the delicate balance between osteoclastic bone resorption and osteoblastic bone formation. However, excessive activation of osteoclasts is responsible for many bone diseases such as osteoporosis, Paget disease, and tumor bone metastasis. Agents that could inhibit osteoclast formation or function are regarded as promising alternatives to treat osteoclast-related diseases. Recently, traditional Chinese medicine has attracted attention because of its multiple activities in bone metabolism. Among them, gastrodin has been reported as an anti-osteoporosis agent that reduces reactive oxygen species. However, the direct action of gastrodin on osteoclast differentiationmore » and bone resorption, and its underlying molecular mechanism, remain unknown. In this study, we investigated the effects of gastrodin on receptor activator NF-κB ligand (RANKL)-activated osteoclasts formation and bone resorption. Our results showed that gastrodin retarded RANKL-induced osteoclast differentiation efficiently by downregulating transcriptional and translational expression of nuclear factor of activated T cells cl (NFATc1), a major factor in RANKL-mediated osteoclastogenesis. Meanwhile, gastrodin prevented osteoclast maturation and migration by inhibiting the gene expression of dendrocyte expressed seven transmembrane protein (DC-STAMP), an osteoclastic-specific gene that controls cells fusion and movement. And gastrodin prevented RANKL-induced osteoclastic bone erosion in vitro. In addition, gastrodin also stimulated bone mesenchymal stem cell (BMSC) spreading and osseointegration in titanium plate. In summary, gastrodin could prevent osteoclasts formation and bone resorption via blockage of NFATc1 activity, and stimulate osseointegration in vitro. Gastrodin could be developed as a potent phytochemical candidate to treat osteolytic diseases. - Highlights: • Gastrodin suppresses osteoclasts formation and function in vitro. • Gastrodin impairs NFATc1 activation. • Gastrodin stimulates osseointegration in vitro. • Gastrodin may be used for treating osteoclast related diseases.« less
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Deng, Yuan; Jiang, Chuan; Li, Cuidi; Li, Tao; Peng, Mingzheng; Wang, Jinwu; Dai, Kerong
2017-07-17
Synthetic bone scaffolds have potential application in repairing large bone defects, however, inefficient vascularization after implantation remains the major issue of graft failure. Herein, porous β-tricalcium phosphate (β-TCP) scaffolds with calcium silicate (CS) were 3D printed, and pre-seeded with co-cultured human umbilical cord vein endothelial cells (HUVECs) and human bone marrow stromal cells (hBMSCs) to construct tissue engineering scaffolds with accelerated vascularization and better bone formation. Results showed that in vitro β-TCP scaffolds doped with 5% CS (5%CS/β-TCP) were biocompatible, and stimulated angiogenesis and osteogenesis. The results also showed that 5%CS/β-TCP scaffolds not only stimulated co-cultured cells angiogenesis on Matrigel, but also stimulated co-cultured cells to form microcapillary-like structures on scaffolds, and promoted migration of BMSCs by stimulating co-cultured cells to secrete PDGF-BB and CXCL12 into the surrounding environment. Moreover, 5%CS/β-TCP scaffolds enhanced vascularization and osteoinduction in comparison with β-TCP, and synergized with co-cultured cells to further increase early vessel formation, which was accompanied by earlier and better ectopic bone formation when implanted subcutaneously in nude mice. Thus, our findings suggest that porous 5%CS/β-TCP scaffolds seeded with co-cultured cells provide new strategy for accelerating tissue engineering scaffolds vascularization and osteogenesis, and show potential as treatment for large bone defects.
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Novel Development of Phosphate Treated Porous Hydroxyapatite.
Doi, Kazuya; Abe, Yasuhiko; Kobatake, Reiko; Okazaki, Yohei; Oki, Yoshifumi; Naito, Yoshihito; Prananingrum, Widyasri; Tsuga, Kazuhiro
2017-12-08
Phosphoric acid-etching treatment to the hydroxyapatite (HA) surface can modify the solubility calcium structure. The aim of the present study was to develop phosphate treated porous HA, and the characteristic structures and stimulation abilities of bone formation were evaluated to determine its suitability as a new type of bone graft material. Although the phosphoric acid-etching treatment did not alter the three-dimensional structure, a micrometer-scale rough surface topography was created on the porous HA surface. Compared to porous HA, the porosity of phosphate treated porous HA was slightly higher and the mechanical strength was lower. Two weeks after placement of the cylindrical porous or phosphate treated porous HA in a rabbit femur, newly formed bone was detected in both groups. At the central portion of the bone defect area, substantial bone formation was detected in the phosphate treated porous HA group, with a significantly higher bone formation ratio than detected in the porous HA group. These results indicate that phosphate treated porous HA has a superior surface topography and bone formation abilities in vivo owing to the capacity for both osteoconduction and stimulation abilities of bone formation conferred by phosphoric acid etching.
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Novel Development of Phosphate Treated Porous Hydroxyapatite
Doi, Kazuya; Abe, Yasuhiko; Kobatake, Reiko; Okazaki, Yohei; Oki, Yoshifumi; Naito, Yoshihito; Prananingrum, Widyasri; Tsuga, Kazuhiro
2017-01-01
Phosphoric acid-etching treatment to the hydroxyapatite (HA) surface can modify the solubility calcium structure. The aim of the present study was to develop phosphate treated porous HA, and the characteristic structures and stimulation abilities of bone formation were evaluated to determine its suitability as a new type of bone graft material. Although the phosphoric acid-etching treatment did not alter the three-dimensional structure, a micrometer-scale rough surface topography was created on the porous HA surface. Compared to porous HA, the porosity of phosphate treated porous HA was slightly higher and the mechanical strength was lower. Two weeks after placement of the cylindrical porous or phosphate treated porous HA in a rabbit femur, newly formed bone was detected in both groups. At the central portion of the bone defect area, substantial bone formation was detected in the phosphate treated porous HA group, with a significantly higher bone formation ratio than detected in the porous HA group. These results indicate that phosphate treated porous HA has a superior surface topography and bone formation abilities in vivo owing to the capacity for both osteoconduction and stimulation abilities of bone formation conferred by phosphoric acid etching. PMID:29292788
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Kassem, Ali; Lindholm, Catharina; Lerner, Ulf H
2016-01-01
Severe Staphylococcus aureus (S. aureus) infections pose an immense threat to population health and constitute a great burden for the health care worldwide. Inter alia, S. aureus septic arthritis is a disease with high mortality and morbidity caused by destruction of the infected joints and systemic bone loss, osteoporosis. Toll-Like receptors (TLRs) are innate immune cell receptors recognizing a variety of microbial molecules and structures. S. aureus recognition via TLR2 initiates a signaling cascade resulting in production of various cytokines, but the mechanisms by which S. aureus causes rapid and excessive bone loss are still unclear. We, therefore, investigated how S. aureus regulates periosteal/endosteal osteoclast formation and bone resorption. S. aureus stimulation of neonatal mouse parietal bone induced ex vivo bone resorption and osteoclastic gene expression. This effect was associated with increased mRNA and protein expression of receptor activator of NF-kB ligand (RANKL) without significant change in osteoprotegerin (OPG) expression. Bone resorption induced by S. aureus was abolished by OPG. S. aureus increased the expression of osteoclastogenic cytokines and prostaglandins in the parietal bones but the stimulatory effect of S. aureus on bone resorption and Tnfsf11 mRNA expression was independent of these cytokines and prostaglandins. Stimulation of isolated periosteal osteoblasts with S. aureus also resulted in increased expression of Tnfsf11 mRNA, an effect lost in osteoblasts from Tlr2 knockout mice. S. aureus stimulated osteoclastogenesis in isolated periosteal cells without affecting RANKL-stimulated resorption. In contrast, S. aureus inhibited RANKL-induced osteoclast formation in bone marrow macrophages. These data show that S. aureus enhances bone resorption and periosteal osteoclast formation by increasing osteoblast RANKL production through TLR2. Our study indicates the importance of using different in vitro approaches for studies of how S. aureus regulates osteoclastogenesis to obtain better understanding of the complex mechanisms of S. aureus induced bone destruction in vivo. PMID:27311019
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Sun, Li; Zhu, Ling-Ling; Lu, Ping; Yuen, Tony; Li, Jianhua; Ma, Risheng; Baliram, Ramkumarie; Moonga, Surinder S.; Liu, Peng; Zallone, Alberta; New, Maria I.; Davies, Terry F.; Zaidi, Mone
2013-01-01
Clinical data showing correlations between low thyroid-stimulating hormone (TSH) levels and high bone turnover markers, low bone mineral density, and an increased risk of osteoporosis-related fractures are buttressed by mouse genetic and pharmacological studies identifying a direct action of TSH on the skeleton. Here we show that the skeletal actions of TSH deficiency are mediated, in part, through TNFα. Compound mouse mutants generated by genetically deleting the Tnfα gene on a Tshr−/− (homozygote) or Tshr+/− (heterozygote) background resulted in full rescue of the osteoporosis, low bone formation, and hyperresorption that accompany TSH deficiency. Studies using ex vivo bone marrow cell cultures showed that TSH inhibits and stimulates TNFα production from macrophages and osteoblasts, respectively. TNFα, in turn, stimulates osteoclastogenesis but also enhances the production in bone marrow of a variant TSHβ. This locally produced TSH suppresses osteoclast formation in a negative feedback loop. We speculate that TNFα elevations due to low TSH signaling in human hyperthyroidism contribute to the bone loss that has traditionally been attributed solely to high thyroid hormone levels. PMID:23716650
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Walker, Emma C.; McGregor, Narelle E.; Poulton, Ingrid J.; Solano, Melissa; Pompolo, Sueli; Fernandes, Tania J.; Constable, Matthew J.; Nicholson, Geoff C.; Zhang, Jian-Guo; Nicola, Nicos A.; Gillespie, Matthew T.; Martin, T. John; Sims, Natalie A.
2010-01-01
Effective osteoporosis therapy requires agents that increase the amount and/or quality of bone. Any modification of osteoclast-mediated bone resorption by disease or drug treatment, however, elicits a parallel change in osteoblast-mediated bone formation because the processes are tightly coupled. Anabolic approaches now focus on uncoupling osteoblast action from osteoclast formation, for example, by inhibiting sclerostin, an inhibitor of bone formation that does not influence osteoclast differentiation. Here, we report that oncostatin M (OSM) is produced by osteoblasts and osteocytes in mouse bone and that it has distinct effects when acting through 2 different receptors, OSM receptor (OSMR) and leukemia inhibitory factor receptor (LIFR). Specifically, mouse OSM (mOSM) inhibited sclerostin production in a stromal cell line and in primary murine osteoblast cultures by acting through LIFR. In contrast, when acting through OSMR, mOSM stimulated RANKL production and osteoclast formation. A key role for OSMR in bone turnover was confirmed by the osteopetrotic phenotype of mice lacking OSMR. Furthermore, in contrast to the accepted model, in which mOSM acts only through OSMR, mOSM inhibited sclerostin expression in Osmr–/– osteoblasts and enhanced bone formation in vivo. These data reveal what we believe to be a novel pathway by which bone formation can be stimulated independently of bone resorption and provide new insights into OSMR and LIFR signaling that are relevant to other medical conditions, including cardiovascular and neurodegenerative diseases and cancer. PMID:20051625
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Early mechanical stimulation only permits timely bone healing in sheep.
Tufekci, Pelin; Tavakoli, Aramesh; Dlaska, Constantin; Neumann, Mirjam; Shanker, Mihir; Saifzadeh, Siamak; Steck, Roland; Schuetz, Michael; Epari, Devakar
2018-06-01
Bone fracture healing is sensitive to the fixation stability. However, it is unclear which phases of healing are mechano-sensitive and if mechanical stimulation is required throughout repair. In this study, a novel bone defect model, which isolates an experimental fracture from functional loading, was applied in sheep to investigate if stimulation limited to the early proliferative phase is sufficient for bone healing. An active fixator controlled motion in the fracture. Animals of the control group were unstimulated. In the physiological-like group, 1 mm axial compressive movements were applied between day 5 and 21, thereafter the movements were decreased in weekly increments and stopped after 6 weeks. In the early stimulatory group, the movements were stopped after 3 weeks. The experimental fractures were evaluated with mechanical and micro-computed tomography methods after 9 weeks healing. The callus strength of the stimulated fractures (physiological-like and early stimulatory) was greater than the unstimulated control group. The control group was characterized by minimal external callus formation and a lack of bone bridging at 9 weeks. In contrast, the stimulated groups exhibited advanced healing with solid bone formation across the defect. This was confirmed quantitatively by a lower bone volume in the control group compared to the stimulated groups.The novel experimental model permits the application of a well-defined load history to an experimental bone fracture. The poor healing observed in the control group is consistent with under-stimulation. This study has shown early mechanical stimulation only is sufficient for a timely healing outcome. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1790-1796, 2018. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Brady, Robert T.; Trinity Centre for Bioengineering, School of Engineering, Trinity College Dublin; Advanced Materials and BioEngineering Research Centre
Bone formation requires the recruitment, proliferation and osteogenic differentiation of mesenchymal progenitors. A potent stimulus driving this process is mechanical loading, yet the signalling mechanisms underpinning this are incompletely understood. The objective of this study was to investigate the role of the mechanically-stimulated osteocyte and osteoblast secretome in coordinating progenitor contributions to bone formation. Initially osteocytes (MLO-Y4) and osteoblasts (MC3T3) were mechanically stimulated for 24hrs and secreted factors within the conditioned media were collected and used to evaluate mesenchymal stem cell (MSC) and osteoblast recruitment, proliferation and osteogenesis. Paracrine factors secreted by mechanically stimulated osteocytes significantly enhanced MSC migration, proliferationmore » and osteogenesis and furthermore significantly increased osteoblast migration and proliferation when compared to factors secreted by statically cultured osteocytes. Secondly, paracrine factors secreted by mechanically stimulated osteoblasts significantly enhanced MSC migration but surprisingly, in contrast to the osteocyte secretome, inhibited MSC proliferation when compared to factors secreted by statically cultured osteoblasts. A similar trend was observed in osteoblasts. This study provides new information on mechanically driven signalling mechanisms in bone and highlights a contrasting secretome between cells at different stages in the bone lineage, furthering our understanding of loading-induced bone formation and indirect biophysical regulation of osteoprogenitors. - Highlights: • Physically stimulated osteocytes secrete factors that regulate osteoprogenitors. • These factors enhance recruitment, proliferation and osteogenic differentiation. • Physically stimulated osteoblasts secrete factors that also regulate progenitors. • These factors enhance recruitment but inhibit proliferation of osteoprogenitors. • This study highlights a contrasting secretome between osteocytes and osteoblasts.« less
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Osteopenia and osteoporosis in people living with HIV: multiprofessional approach
Lima, Ana Lucia Lei Munhoz; de Oliveira, Priscila Rosalba D; Plapler, Perola Grimberg; Marcolino, Flora Maria D Andrea; de Souza Meirelles, Eduardo; Sugawara, André; Gobbi, Riccardo Gomes; dos Santos, Alexandre Leme Godoy; Camanho, Gilberto Luis
2011-01-01
Increasing bone mineralization abnormalities observed among people living with HIV (PLWHIV) result from various factors relating to the host, the virus, and the antiretrovirals used. Today, HIV infection is considered to be a risk factor for bone mineralization disorders. The test most recommended for diagnosing osteoporosis is measurement of bone mineral density by means of dual energy X-ray absorptiometry at two sites. Osteoporosis treatment has the aims of bone mass improvement and fracture control. A combination of calcium and vitamin D supplementation may reduce the risk of fractures. Antiresorptive drugs act by blocking osteoclastic activity and reducing bone remodeling. On the other hand, bone-forming drugs stimulate osteoblastogenesis, thereby stimulating the formation of bone matrix. Mixed-action medications are those that are capable of both stimulating bone formation and inhibiting reabsorption. Antiresorptive drugs form the group of medications with the greatest quantity of scientific evidence confirming their efficacy in osteoporosis treatment. Physical activity is a health promotion strategy for the general population, but only preliminary data on its real value and benefit among PLWHIV are available, especially in relation to osteoporosis. PMID:22267944
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Osteopenia and osteoporosis in people living with HIV: multiprofessional approach.
Lima, Ana Lucia Lei Munhoz; de Oliveira, Priscila Rosalba D; Plapler, Perola Grimberg; Marcolino, Flora Maria D Andrea; de Souza Meirelles, Eduardo; Sugawara, André; Gobbi, Riccardo Gomes; Dos Santos, Alexandre Leme Godoy; Camanho, Gilberto Luis
2011-01-01
Increasing bone mineralization abnormalities observed among people living with HIV (PLWHIV) result from various factors relating to the host, the virus, and the antiretrovirals used. Today, HIV infection is considered to be a risk factor for bone mineralization disorders. The test most recommended for diagnosing osteoporosis is measurement of bone mineral density by means of dual energy X-ray absorptiometry at two sites. Osteoporosis treatment has the aims of bone mass improvement and fracture control. A combination of calcium and vitamin D supplementation may reduce the risk of fractures. Antiresorptive drugs act by blocking osteoclastic activity and reducing bone remodeling. On the other hand, bone-forming drugs stimulate osteoblastogenesis, thereby stimulating the formation of bone matrix. Mixed-action medications are those that are capable of both stimulating bone formation and inhibiting reabsorption. Antiresorptive drugs form the group of medications with the greatest quantity of scientific evidence confirming their efficacy in osteoporosis treatment. Physical activity is a health promotion strategy for the general population, but only preliminary data on its real value and benefit among PLWHIV are available, especially in relation to osteoporosis.
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Lee, Su-Ui; Park, Sang-Joon; Kwak, Han Bok; Oh, Jaemin; Min, Yong Ki; Kim, Seong Hwan
2008-01-01
In the field of osteoporosis, there has been growing interest in anabolic agents that enhance bone mass and improve bone architecture. In this study, we demonstrated that the ubiquitous plant triterpenoid, ursolic acid, enhances differentiation and mineralization of osteoblasts in vitro. We found that ursolic acid induced the expression of osteoblast-specific genes with the activation of mitogen-activated protein kinases, nuclear factor-kappaB, and activator protein-1. Additionally, noggin, an antagonist of bone morphogenetic proteins (BMPs), inhibited ursolic acid-induced osteoblast differentiation. Noggin also inhibited the activation of Smad and the induction of BMP-2 mRNA expression by ursolic acid in the late stage of osteoblast differentiation. Importantly, ursolic acid was shown to have bone-forming activity in vivo in a mouse calvarial bone formation model. A high proportion of positive immunostaining of BMP-2 was found in the nuclear region of woven bone formed by ursolic acid. These results suggested that ursolic acid has the anabolic potential to stimulate osteoblast differentiation and enhance new bone formation.
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NASA Technical Reports Server (NTRS)
Akamine, T.; Jee, W. S. S.; Ke, H. Z.; Li, X. J.; Lin, B. Y.
1992-01-01
The object of this study was to determine whether prostaglandin E2 (PGE2) can prevent disuse (underloading)-induced cancellous bone loss. Thirteen-month-old retired female Sprague-Dawley breeders served as controls or were subjected to right hindlimb immobilization by bandaging and simultaneously treated subcutaneously daily with 0, 1, 3, or 6 mg PGE2/kg/d for two and six weeks. Histomorphometric analyses were performed on the cancellous bone using double-fluorescent labeled, 20 micron thick, undecalcified distal femoral metaphysis sections. We found that PGE2 administration not only prevented disuse-induced bone loss, but also added extra bone to disuse cancellous bone in a dose-response manner. PGE2 prevented the disuse-induced osteopenia by stimulating more bone formation than and shortening the period of bone remodeling. It activated woven bone formation, stimulated lamellar bone formation, and increased the eroded bone surface above that caused by disuse alone. While underloading increased the remodeling period (sigma), PGE2 treatment of underloaded bone shortened the time for osteoclastic bone resorption and bone remodeling, and thus reduced the remodeling space. The study shows that PGE2 is a powerful anabolic agent that prevents disuse-induced osteopenia and adds extra bone to these same bones.
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Characterization of an Ex vivo Femoral Head Model Assessed by Markers of Bone and Cartilage Turnover
Madsen, Suzi Hoegh; Goettrup, Anne Sofie; Thomsen, Gedske; Christensen, Søren Tvorup; Schultz, Nikolaj; Henriksen, Kim; Bay-Jensen, Anne-Christine; Karsdal, Morten Asser
2011-01-01
Objective: The pathophysiology of osteoarthritis involves the whole joint and is characterized by cartilage degradation and altered subchondral bone turnover. At present, there is a need for biological models that allow investigation of the interactions between the key cellular players in bone/cartilage: osteoblasts, osteoclasts, and chondrocytes. Methods: Femoral heads from 3-, 6-, 9-, and 12-week-old female mice were isolated and cultured for 10 days in serum-free media in the absence or presence of IGF-I (100 nM) (anabolic stimulation) or OSM (10 ng/mL) + TNF-α (20 ng/mL) (catabolic stimulation). Histology on femoral heads before and after culture was performed, and the growth plate size was examined to evaluate the effects on cell metabolism. The conditioned medium was examined for biochemical markers of bone and cartilage degradation/formation. Results: Each age group represented a unique system regarding the interest of bone or cartilage metabolism. Stimulation over 10 days with OSM + TNF-α resulted in depletion of proteoglycans from the cartilage surface in all ages. Furthermore, OSM + TNF-α decreased growth plate size, whereas IGF-I increased the size. Measurements from the conditioned media showed that OSM + TNF-α increased the number of osteoclasts by approximately 80% and induced bone and cartilage degradation by approximately 1200% and approximately 2600%, respectively. Stimulation with IGF-I decreased the osteoclast number and increased cartilage formation by approximately 30%. Conclusion: Biochemical markers and histology together showed that the catabolic stimulation induced degradation and the anabolic stimulation induced formation in the femoral heads. We propose that we have established an explant whole-tissue model for investigating cell-cell interactions, reflecting parts of the processes in the pathogenesis of joint degenerative diseases. PMID:26069585
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NASA Technical Reports Server (NTRS)
Conover, Cheryl A.; Johnstone, Edward W.; Turner, Russell T.; Evans, Glenda L.; John Ballard, F. John; Doran, Patrick M.; Khosla, Sundeep
2002-01-01
Elevated serum levels of insulin-like growth factor binding protein-2 (IGFBP-2) and a precursor form of IGF-II are associated with marked increases in bone formation and skeletal mass in patients with hepatitis C-associated osteosclerosis. In vitro studies indicate that IGF-II in complex with IGFBP-2 has high affinity for bone matrix and is able to stimulate osteoblast proliferation. The purpose of this study was to determine the ability of the IGF-II/IGFBP-2 complex to increase bone mass in vivo. Osteopenia of the femur was induced by unilateral sciatic neurectomy in rats. At the time of surgery, 14-day osmotic minipumps containing vehicle or 2 microg IGF-II+9 microg IGFBP-2/100g body weight/day were implanted subcutaneously in the neck. Bone mineral density (BMD) measurements were taken the day of surgery and 14 days later using a PIXImus small animal densitometer. Neurectomy of the right hindlimb resulted in a 9% decrease in right femur BMD (P<0.05 vs. baseline). This loss in BMD was completely prevented by treatment with IGF-II/IGFBP-2. On the control limb, there was no loss of BMD over the 14 days and IGF-II/IGFBP-2 treatment resulted in a 9% increase in left femur BMD (P<0.05). Bone histomorphometry indicated increases in endocortical and cancellous bone formation rates and in trabecular thickness. These results demonstrate that short-term administration of the IGF-II/IGFBP-2 complex can prevent loss of BMD associated with disuse osteoporosis and stimulate bone formation in adult rats. Furthermore, they provide proof of concept for a novel anabolic approach to increasing bone mass in humans with osteoporosis.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Gilmour, Peter S., E-mail: Peter.Gilmour@astrazeneca.com; O'Shea, Patrick J.; Fagura, Malbinder
Wnt activation by inhibiting glycogen synthase kinase 3 (GSK-3) causes bone anabolism in rodents making GSK-3 a potential therapeutic target for osteoporotic and osteolytic metastatic bone disease. To understand the wnt pathway related to human disease translation, the ability of 3 potent inhibitors of GSK-3 (AZD2858, AR79, AZ13282107) to 1) drive osteoblast differentiation and mineralisation using human adipose-derived stem cells (hADSC) in vitro; and 2) stimulate rat bone formation in vivo was investigated. Bone anabolism/resorption was determined using clinically relevant serum biomarkers as indicators of bone turnover and bone formation assessed in femurs by histopathology and pQCT/μCT imaging. GSK-3 inhibitorsmore » caused β-catenin stabilisation in human and rat mesenchymal stem cells, stimulated hADSC commitment towards osteoblasts and osteogenic mineralisation in vitro. AZD2858 produced time-dependent changes in serum bone turnover biomarkers and increased bone mass over 28 days exposure in rats. After 7 days, AZD2858, AR79 or AZ13282107 exposure increased the bone formation biomarker P1NP, and reduced the resorption biomarker TRAcP-5b, indicating increased bone anabolism and reduced resorption in rats. This biomarker profile was differentiated from anabolic agent PTH{sub 1–34} or the anti-resorptive Alendronate-induced changes. Increased bone formation in cortical and cancellous bone as assessed by femur histopathology supported biomarker changes. 14 day AR79 treatment increased bone mineral density and trabecular thickness, and decreased trabecular number and connectivity assessed by pQCT/μCT. GSK-3 inhibition caused hADSC osteoblastogenesis and mineralisation in vitro. Increased femur bone mass associated with changes in bone turnover biomarkers confirmed in vivo bone formation and indicated uncoupling of bone formation and resorption. - Highlights: • Wnt modulation with 3 novel GSK-3 inhibitors alters bone growth. • Human stem cell osteoblastogenesis and mineralisation produced by GSK-3 inhibition. • In rats, 3 GSK-3 inhibitors produced a unique serum bone turnover biomarker profile. • Enhanced bone formation was seen within 7 to 14 days of compound treatment in rats.« less
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Differential growth factor control of bone formation through osteoprogenitor differentiation.
Chaudhary, L R; Hofmeister, A M; Hruska, K A
2004-03-01
The osteogenic factors bone morphogenetic protein (BMP-7), platelet-derived growth factor (PDGF)-BB, and fibroblast growth factor (FGF-2) regulate the recruitment of osteoprogenitor cells and their proliferation and differentiation into mature osteoblasts. However, their mechanisms of action on osteoprogenitor cell growth, differentiation, and bone mineralization remain unclear. Here, we tested the hypothesis that these osteogenic agents were capable of regulating osteoblast differentiation and bone formation in vitro. Normal human bone marrow stromal (HBMS) cells were treated with BMP-7 (40 ng ml(-1)), PDGF-BB (20 ng ml(-1)), FGF-2 (20 ng ml(-1)), or FGF-2 plus BMP-7 for 28 days in a serum-containing medium with 10 mM beta-glycerophosphate and 50 microg ml(-1) ascorbic acid. BMP-7 stimulated a morphological change to cuboidal-shaped cells, increased alkaline phosphatase (ALKP) activity, bone sialoprotein (BSP) gene expression, and alizarin red S positive nodule formation. Hydroxyapatite (HA) crystal deposition in the nodules was demonstrated by Fourier transform infrared (FTIR) spectroscopy only in BMP-7- and dexamethasone (DEX)-treated cells. DEX-treated cells appeared elongated and fibroblast-like compared to BMP-7-treated cells. FGF-2 did not stimulate ALKP, and cell morphology was dystrophic. PDGF-BB had little or no effect on ALKP activity and biomineralization. Alizarin Red S staining of cells and calcium assay indicated that BMP-7, DEX, and FGF-2 enhanced calcium mineral deposition, but FTIR spectroscopic analysis demonstrated no formation of HA similar to human bone in control, PDGF-BB-, and FGF-2-treated samples. Thus, FGF-2 stimulated amorphous octacalcium phosphate mineral deposition that failed to mature into HA. Interestingly, FGF-2 abrogated BMP-7-induced ALKP activity and HA formation. Results demonstrate that BMP-7 was competent as a sole factor in the differentiation of human bone marrow stromal cells to bone-forming osteoblasts confirmed by FTIR examination of mineralized matrix. Other growth factors, PDGF, and FGF-2 were incompetent as sole factors, and FGF-2 inhibited BMP-7-stimulated osteoblast differentiation.
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WAIF1 Is a Cell-Surface CTHRC1 Binding Protein Coupling Bone Resorption and Formation.
Matsuoka, Kazuhiko; Kohara, Yukihiro; Naoe, Yoshinori; Watanabe, Atsushi; Ito, Masako; Ikeda, Kyoji; Takeshita, Sunao
2018-04-06
The osteoclast-derived collagen triple helix repeat containing 1 (CTHRC1) protein stimulates osteoblast differentiation, but the underlying mechanism remains unclear. Here, we identified Wnt-activated inhibitory factor 1 (WAIF1)/5T4 as a cell-surface protein binding CTHRC1. The WAIF1-encoding Trophoblast glycoprotein (Tpbg) gene, which is abundantly expressed in the brain and bone but not in other tissues, showed the same expression pattern as Cthrc1. Tpbg downregulation in marrow stromal cells reduced CTHRC1 binding and CTHRC1-stimulated alkaline phosphatase activity through PKCδ activation of MEK/ERK, suggesting a novel WAIF1/PKCδ/ERK pathway triggered by CTHRC1. Unexpectedly, osteoblast lineage-specific deletion of Tpbg downregulated Rankl expression in mouse bones and reduced both bone formation and resorption; importantly, it impaired bone mass recovery following RANKL-induced resorption, reproducing the phenotype of osteoclast-specific Cthrc1 deficiency. Thus, the binding of osteoclast-derived CTHRC1 to WAIF1 in stromal cells activates PKCδ-ERK osteoblastogenic signaling and serves as a key molecular link between bone resorption and formation during bone remodeling. © 2018 American Society for Bone and Mineral Research. © 2018 American Society for Bone and Mineral Research.
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Komatsu, Koichiro; Shimada, Akemi; Shibata, Tatsuya; Wada, Satoshi; Ideno, Hisashi; Nakashima, Kazuhisa; Amizuka, Norio; Noda, Masaki; Nifuji, Akira
2013-11-01
Bisphosphonates (BPs) are a major class of antiresorptive drug, and their molecular mechanisms of antiresorptive action have been extensively studied. Recent studies have suggested that BPs target bone-forming cells as well as bone-resorbing cells. We previously demonstrated that local application of a nitrogen-containing BP (N-BP), alendronate (ALN), for a short period of time increased bone tissue in a rat tooth replantation model. Here, we investigated cellular mechanisms of bone formation by ALN. Bone histomorphometry confirmed that bone formation was increased by local application of ALN. ALN increased proliferation of bone-forming cells residing on the bone surface, whereas it suppressed the number of tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts in vivo. Moreover, ALN treatment induced more alkaline phosphatase-positive and osteocalcin-positive cells on the bone surface than PBS treatment. In vitro studies revealed that pulse treatment with ALN promoted osteocalcin expression. To track the target cells of N-BPs, we applied fluorescence-labeled ALN (F-ALN) in vivo and in vitro. F-ALN was taken into bone-forming cells both in vivo and in vitro. This intracellular uptake was inhibited by endocytosis inhibitors. Furthermore, the endocytosis inhibitor dansylcadaverine (DC) suppressed ALN-stimulated osteoblastic differentiation in vitro and it suppressed the increase in alkaline phosphatase-positive bone-forming cells and subsequent bone formation in vivo. DC also blocked the inhibition of Rap1A prenylation by ALN in the osteoblastic cells. These data suggest that local application of ALN promotes bone formation by stimulating proliferation and differentiation of bone-forming cells as well as inhibiting osteoclast function. These effects may occur through endocytic incorporation of ALN and subsequent inhibition of protein prenylation.
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Lawton, Jonathan M; Habib, Mariam; Ma, Bingkui; Brooks, Roger A; Best, Serena M; Lewis, Andrew L; Rushton, Neil; Bonfield, William
2017-08-17
The effect of introducing cationic charge into phosphorylcholine (PC)-based polymers has been investigated in this study with a view to using these materials as coatings to improve bone formation and osseointegration at the bone-implant interface. PC-based polymers, which have been used in a variety of medical devices to improve biocompatibility, are associated with low protein adsorption resulting in reduced complement activation, inflammatory response and cell adhesion. However, in some applications, such as orthopaedics, good integration between the implant and bone is needed to allow the distribution of loading stresses and a bioactive response is required. It has previously been shown that the incorporation of cationic charge into PC-based polymers may increase protein adsorption that stimulates subsequent cell adhesion. In this paper, the effect of cationic charge in PC-based polymers on human osteoblasts (HObs) in vitro and the effect of these polymers on bone formation in the rat tibia was assessed. Increasing PC positive surface charge increased HOb cell adhesion and stimulated increased cell differentiation and the production of calcium phosphate deposits. However, when implanted in bone these materials were at best biotolerant, stimulating the production of fibrous tissue and areas of loosely associated matrix (LAM) around the implant. Their development, as formulated in this study, as bone interfacing implant coatings is therefore not warranted.
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Quint, Patrick; Ruan, Ming; Pederson, Larry; Kassem, Moustapha; Westendorf, Jennifer J.; Khosla, Sundeep; Oursler, Merry Jo
2013-01-01
Normal bone turnover requires tight coupling of bone resorption and bone formation to preserve bone quantity and structure. With aging and during several pathological conditions, this coupling breaks down, leading to either net bone loss or excess bone formation. To preserve or restore normal bone metabolism, it is crucial to determine the mechanisms by which osteoclasts and osteoblast precursors interact and contribute to coupling. We showed that osteoclasts produce the chemokine sphingosine 1-phosphate (S1P), which stimulates osteoblast migration. Thus, osteoclast-derived S1P may recruit osteoblasts to sites of bone resorption as an initial step in replacing lost bone. In this study we investigated the mechanisms by which S1P stimulates mesenchymal (skeletal) cell chemotaxis. S1P treatment of mesenchymal (skeletal) cells activated RhoA GTPase, but this small G protein did not contribute to migration. Rather, two S1P receptors, S1PR1 and S1PR2, coordinately promoted migration through activation of the JAK/STAT3 and FAK/PI3K/AKT signaling pathways, respectively. These data demonstrate that the chemokine S1P couples bone formation to bone resorption through activation of kinase signaling pathways. PMID:23300082
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Liu, Yan-Qiu; Hong, Zhi-Lai; Zhan, Li-Bin; Chu, Hui-Ying; Zhang, Xiao-Zhe; Li, Guo-Hui
2016-08-25
Bone homeostasis is maintained by formation and destruction of bone, which are two processes tightly coupled and controlled. Targeting both stimulation on bone formation and suppression on bone resorption becomes a promising strategy for treating osteoporosis. In this study, we examined the effect of wedelolactone, a natural product from Ecliptae herba, on osteoblastogenesis as well as osteoclastogenesis. In mouse bone marrow mesenchymal stem cells (BMSC), wedelolactone stimulated osteoblast differentiation and bone mineralization. At the molecular level, wedelolactone directly inhibited GSK3β activity and enhanced the phosphorylation of GSK3β, thereafter stimulated the nuclear translocation of β-catenin and runx2. The expression of osteoblastogenesis-related marker gene including osteorix, osteocalcin and runx2 increased. At the same concentration range, wedelolactone inhibited RANKL-induced preosteoclastic RAW264.7 actin-ring formation and bone resorption pits. Further, wedelolactone blocked NF-kB/p65 phosphorylation and abrogated the NFATc1 nuclear translocation. As a result, osteoclastogenesis-related marker gene expression decreased, including c-src, c-fos, and cathepsin K. In ovariectomized mice, administration of wedelolactone prevented ovariectomy-induced bone loss by enhancing osteoblast activity and inhibiting osteoclast activity. Together, these data demonstrated that wedelolactone facilitated osteoblastogenesis through Wnt/GSK3β/β-catenin signaling pathway and suppressed RANKL-induced osteoclastogenesis through NF-κB/c-fos/NFATc1 pathway. These results suggested that wedelolacone could be a novel dual functional therapeutic agent for osteoporosis.
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NASA Technical Reports Server (NTRS)
Rubin, C.; Xu, G.; Judex, S.
2001-01-01
It is generally believed that mechanical signals must be large in order to be anabolic to bone tissue. Recent evidence indicates, however, that extremely low-magnitude (<10 microstrain) mechanical signals readily stimulate bone formation if induced at a high frequency. We examined the ability of extremely low-magnitude, high-frequency mechanical signals to restore anabolic bone cell activity inhibited by disuse. Adult female rats were randomly assigned to six groups: baseline control, age-matched control, mechanically stimulated for 10 min/day, disuse (hind limb suspension), disuse interrupted by 10 min/day of weight bearing, and disuse interrupted by 10 min/day of mechanical stimulation. After a 28 day protocol, bone formation rates (BFR) in the proximal tibia of mechanically stimulated rats increased compared with age-matched control (+97%). Disuse alone reduced BFR (-92%), a suppression only slightly curbed when disuse was interrupted by 10 min of weight bearing (-61%). In contrast, disuse interrupted by 10 min per day of low-level mechanical intervention normalized BFR to values seen in age-matched controls. This work indicates that this noninvasive, extremely low-level stimulus may provide an effective biomechanical intervention for the bone loss that plagues long-term space flight, bed rest, or immobilization caused by paralysis.
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[Endogenous pyrogen formation by bone marrow cells].
Efremov, O M; Sorokin, A V; El'kina, O A
1978-01-01
The cells of the rabbit bone marrow produced endogenous pyrogen in response to stimulation with bacterial lipopolysaccharide. Incubation of the cells in medium No 199 containing a 15% homologous serum is optimal for the release of pyrogen. It is supposed that the cells of the bone marrow take part in the formation of endgenous pyrogen and in the mechanism of pyrexia in the organism.
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Spinal Cord Injury-Induced Osteoporosis: Pathogenesis and Emerging Therapies
Battaglino, Ricardo A.; Lazzari, Antonio A.; Garshick, Eric; Morse, Leslie R.
2012-01-01
Spinal cord injury causes rapid, severe osteoporosis with increased fracture risk. Mechanical unloading after paralysis results in increased osteocyte expression of sclerostin, suppressed bone formation, and indirect stimulation of bone resorption. At this time there are no clinical guidelines to prevent bone loss after SCI and fractures are common. More research is required to define the pathophysiology and epidemiology of SCI-induced osteoporosis. This review summarizes emerging therapeutics including anti-sclerostin antibodies, mechanical loading of the lower extremity with electrical stimulation, and mechanical stimulation via vibration therapy. PMID:22983921
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In vitro bioactivity of akermanite ceramics.
Wu, Chengtie; Chang, Jiang; Ni, Siyu; Wang, Junying
2006-01-01
In this study, the bone-like apatite-formation ability of akermanite ceramics (Ca2MgSi2O7) in simulated body fluid (SBF) and the effects of ionic products from akermanite dissolution on osteoblasts and mouse fibroblasts (cell line L929) were investigated. In addition, osteoblast morphology and proliferation on the ceramics were evaluated. The results showed that akermanite ceramics possessed bone-like apatite-formation ability comparable with bioactive wollastonite ceramics (CaSiO3) after 20 days of soaking in SBF and the mechanism of bone-like apatite formation on akermanite ceramics is similar to that of wollastonite ceramics. The Ca, Si, and Mg ions from akermanite dissolution at certain ranges of concentration significantly stimulated osteoblast and L929 cell proliferation. Furthermore, osteoblasts spread well on the surface of akermanite ceramics, and proliferated with increasing the culture time. The results showed that akermanite ceramics possess bone-like apatite-formation ability and can release soluble ionic products to stimulate cell proliferation, which indicated good bioactivity. (c) 2005 Wiley Periodicals, Inc
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Responds of Bone Cells to Microgravity: Ground-Based Research
NASA Astrophysics Data System (ADS)
Zhang, Jian; Li, Jingbao; Xu, Huiyun; Yang, Pengfei; Xie, Li; Qian, Airong; Zhao, Yong; Shang, Peng
2015-11-01
Severe loss of bone occurs due to long-duration spaceflight. Mechanical loading stimulates bone formation, while bone degradation happens under mechanical unloading. Bone remodeling is a dynamic process in which bone formation and bone resorption are tightly coupled. Increased bone resorption and decreased bone formation caused by reduced mechanical loading, generally result in disrupted bone remodeling. Bone remodeling is orchestrated by multiple bone cells including osteoblast, osteocyte, osteoclast and mesenchymal stem cell. It is yet not clear that how these bone cells sense altered gravity, translate physical stimulus into biochemical signals, and then regulate themselves structurally and functionally. In this paper, studies elucidating the bioeffects of microgravity on bone cells (osteoblast, osteocyte, osteoclast, mesenchymal stem cell) using various platforms including spaceflight and ground-based simulated microgravity were summarized. Promising gravity-sensitive signaling pathways and protein molecules were proposed.
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Collin-Osdoby, P; Rothe, L; Bekker, S; Anderson, F; Osdoby, P
2000-03-01
High nitric oxide (NO) levels inhibit osteoclast (OC)-mediated bone resorption in vivo and in vitro, and nitrate donors protect against estrogen-deficient bone loss in postmenopausal women. Conversely, decreased NO production potentiates OC bone resorption in vitro and is associated with in vivo bone loss in rats and humans. Previously, we reported that bone sections from rats administered aminoguanidine (AG), a selective inhibitor of NO production via inducible NO synthase, exhibited both increased OC resorptive activity as well as greater numbers of OC. Here, we investigated further whether AG promoted osteoclastogenesis, in addition to stimulating mature OC function, using a modified in vivo chick chorioallantoic membrane (CAM) system and an in vitro chick bone marrow OC-like cell developmental model. AG, focally administered in small agarose plugs placed directly adjacent to a bone chip implanted on the CAM, dose-dependently elicited neoangiogenesis while stimulating the number, size, and bone pit resorptive activity of individual OC ectopically formed in vivo. In addition to enhancing OC precursor recruitment via neoangiogenesis, AG also exerted other vascular-independent effects on osteoclastogenesis. Thus, AG promoted the in vitro fusion and formation from bone marrow precursor cells of larger OC-like cells that contained more nuclei per cell and exhibited multiple OC differentiation markers. AG stimulated development was inversely correlated with declining medium nitrite levels. In contrast, three different NO donors each dose-dependently inhibited in vitro OC-like cell development while raising medium nitrite levels. Therefore, NO sensitively regulates OC-mediated bone resorption through affecting OC recruitment (angiogenesis), formation (fusion and differentiation), and bone resorptive activity in vitro and in vivo. Possibly, the stimulation of neoangiogenesis and OC-mediated bone remodeling via AG or other pro-angiogenic agents may find clinical applications in reconstructive surgery, fracture repair, or the treatment of avascular necrosis.
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Mechanotransduction and the functional response of bone to mechanical strain
NASA Technical Reports Server (NTRS)
Duncan, R. L.; Turner, C. H.
1995-01-01
Mechanotransduction plays a crucial role in the physiology of many tissues including bone. Mechanical loading can inhibit bone resorption and increase bone formation in vivo. In bone, the process of mechanotransduction can be divided into four distinct steps: (1) mechanocoupling, (2) biochemical coupling, (3) transmission of signal, and (4) effector cell response. In mechanocoupling, mechanical loads in vivo cause deformations in bone that stretch bone cells within and lining the bone matrix and create fluid movement within the canaliculae of bone. Dynamic loading, which is associated with extracellular fluid flow and the creation of streaming potentials within bone, is most effective for stimulating new bone formation in vivo. Bone cells in vitro are stimulated to produce second messengers when exposed to fluid flow or mechanical stretch. In biochemical coupling, the possible mechanisms for the coupling of cell-level mechanical signals into intracellular biochemical signals include force transduction through the integrin-cytoskeleton-nuclear matrix structure, stretch-activated cation channels within the cell membrane, G protein-dependent pathways, and linkage between the cytoskeleton and the phospholipase C or phospholipase A pathways. The tight interaction of each of these pathways would suggest that the entire cell is a mechanosensor and there are many different pathways available for the transduction of a mechanical signal. In the transmission of signal, osteoblasts, osteocytes, and bone lining cells may act as sensors of mechanical signals and may communicate the signal through cell processes connected by gap junctions. These cells also produce paracrine factors that may signal osteoprogenitors to differentiate into osteoblasts and attach to the bone surface. Insulin-like growth factors and prostaglandins are possible candidates for intermediaries in signal transduction. In the effector cell response, the effects of mechanical loading are dependent upon the magnitude, duration, and rate of the applied load. Longer duration, lower amplitude loading has the same effect on bone formation as loads with short duration and high amplitude. Loading must be cyclic to stimulate new bone formation. Aging greatly reduces the osteogenic effects of mechanical loading in vivo. Also, some hormones may interact with local mechanical signals to change the sensitivity of the sensor or effector cells to mechanical load.
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Bone anabolics in osteoporosis: Actuality and perspectives
Montagnani, Andrea
2014-01-01
Vertebral and nonvertebral fractures prevention is the main goal for osteoporosis therapy by inhibiting bone resorption and/or stimulating bone formation. Antiresorptive drugs decrease the activation frequency, thereby determining a secondary decrease in bone formation rate and a low bone turnover. Bisphosphonates are today’s mainstay among antiresorptive treatment of osteoporosis. Also, oral selective estrogen receptor modulators and recently denosumab have a negative effect on bone turnover. Agents active on bone formation are considered a better perspective in the treatment of severe osteoporosis. Recombinant-human parathyroid hormone (PTH) has showed to increase bone formation and significantly decrease vertebral fractures in severe patients, but with a modest effect on nonvertebral fractures. The study of Wnt signaling pathway, that induces prevalently an osteoblastic activity, opens large possibilities to antagonists of Wnt-inhibitors, such as sclerostin antibodies and dickkopf-1 antagonists, with potential effects not only on trabecular bone but also on cortical bone. PMID:25035827
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MMP-8, A Breast Cancer Bone Metastasis Suppressor Gene
2006-08-01
new protein synthesis. This event is particularly important in situations such as tissue repair following injury . PTH and TGF-b1 stimulated LTBP-1...osteoclastogenesis inhi- bitory factor in the stimulation of osteoclast formation by parathyroid hormone in mouse bone cells. Eur J Endo - crinol 142:661–664...done to determine cross-sectional area, bone volume, and perios - teal perimeter (Ps.Pm). The endocortical sur- face was outlined, and the analysis
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Sun, Li; Zaidi, Mone; Zallone, Alberta
2014-01-01
One of the most meaningful results recently achieved in bone research has been to reveal that the pituitary hormones have profound effect on bone, so that the pituitary-bone axis has become one of the major topics in skeletal physiology. Here, we discuss the relevant evidence about the posterior pituitary hormone oxytocin (OT), previously thought to exclusively regulate parturition and breastfeeding, which has recently been established to directly regulate bone mass. Both osteoblasts and osteoclasts express OT receptors (OTR), whose stimulation enhances bone mass. Consistent with this, mice deficient in OT or OTR display profoundly impaired bone formation. In contrast, bone resorption remains unaffected in OT deficiency because, even while OT stimulates the genesis of osteoclasts, it inhibits their resorptive function. Furthermore, in addition to its origin from the pituitary, OT is also produced by bone marrow osteoblasts acting as paracrine-autocrine regulator of bone formation modulated by estrogens. In turn, the power of estrogen to increase bone mass is OTR-dependent. Therefore, OTR−/− mice injected with 17β-estradiol do not show any effects on bone formation parameters, while the same treatment increases bone mass in wild-type mice. These findings together provide evidence for an anabolic action of OT in regulating bone mass and suggest that bone marrow OT may enhance the bone-forming action of estrogen through an autocrine circuit. This established new physiological role for OT in the maintenance of skeletal integrity further suggests the potential use of this hormone for the treatment of osteoporosis. PMID:25209411
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Al Mamun, Md Abdullah; Hosen, Mohammad Jakir; Khatun, Amina; Alam, M Masihul; Al-Bari, Md Abdul Alim
2017-09-08
The Tridax procumbens extracts (TPE) are known for their ethno-medicinal properties to increase osteogenic functioning in mesenchymal stem cells. Recently, we found that the T. procumbens flavonoids (TPF) significantly suppressed the RANKL-induced osteoclasts differentiation and bone resorption. The TPF also promoted osteoblasts differentiation and bone formation demonstrated by increasing bone formation markers in cultured mouse primary osteoblasts. However, the effects of the TPF on in vivo bone formation remain unclear. In this study, we investigated the effects of the TPF on in vivo bone formation, injected the TPF (20 mg/kg) twice a day in the low calcium diet mice and killed them after 21 day. Radiographic and histomorphometric analyses were performed on the dissected bones to determine the anabolic effects of the TPF. Bone mineral density and bone mineral content of the TPF-treated mice were significantly increased compared to the control mice. Bone formation-related indices like osteoblast number, osteoblast surface, bone volume, mineralizing surface, mineral apposition rate and bone formation rate were significantly increased in the TPF-treated mice compared to the control mice. Our findings point towards the stimulation of bone formation by TPF, suggested that the TPF could be a potential natural anabolic agent to treat patients with bone loss-associated diseases such as osteoporosis.
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NASA Astrophysics Data System (ADS)
Kao, Chia-Tze; Hsu, Tuan-Ti; Huang, Tsui-Hsien; Wu, Yu-Tin; Chen, Yi-Wen; Shie, Ming-You
2016-02-01
Angiogenesis plays an important role in determining the biostimulation of bone regeneration, in either new bone or blood vessel formation. Human umbilical cord cells (HUVECs) are important effector cells in angiogenesis and are indispensable for osteogenesis and for their heterogeneity and plasticity. However, there are very few studies about the effects of HUVECs on diode laser-stimulated/regulated osteogenesis. In this study, we used diode laser as a model biostimulation to examine the role of HUVECs on laser-stimulated osteogenesis. Several bone formation-related proteins were also significantly up-regulated by the diode laser stimulation, indicating that HUVECs may participate in diode laser-stimulated osteogenesis. Interestingly, when human mesenchymal stem cells (hMSCs) cultured with HUVECs were diode laser-treated, the osteogenesis differentiation of the hMSCs was significantly promoted, indicating the important role of HUVECs in diode laser-enhanced osteogenesis. Adequately activated HUVECs are vital for the success of diode laser-stimulated hard-tissue regeneration. These findings provided valuable insights into the mechanism of diode laser-stimulated osteogenic differentiation, and a strategy to optimize the evaluation system for the in vitro osteogenesis capacity of laser treatment in periodontal repair.
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2012-01-01
Background Epimedii herba is one of the most frequently used herbs in formulas that are prescribed for the treatment of osteoporosis in China and its main constituent is Epimedium pubescen flavonoid (EPF). However, it is unclear whether EPF during chronic exposure to cigarette smoke may have a protective influence on the skeleton. The present study investigated the effect of EPF on bone mineral status and bone turnover in a rat model of human relatively high exposure to cigarette smoke. Methods Fifty male Wistar rats were randomized into five groups: controls, passive smoking groups and passive smoking rats administered EPF at three dosage levels (75, 150 or 300 mg/kg/day) in drinking water for 4 months. A rat model of passive smoking was prepared by breeding male rats in a cigarette-smoking box. Bone mineral content (BMC), bone mineral density (BMD), bone turnover markers, bone histomorphometric parameters and biomechanical properties were examined. Results Smoke exposure decreased BMC and BMD, increased bone turnover (inhibited bone formation and stimulated its resorption), affected bone histomorphometry (increased trabecular separation and osteoclast surface per bone surface; decreased trabecular bone volume, trabecular thickness, trabecular number, cortical thickness, bone formation rate and osteoblast surface per bone surface), and reduced mechanical properties. EPF supplementation during cigarette smoke exposure prevented smoke-induced changes in bone mineral status and bone turnover. Conclusion The results suggest that EPF can prevent the adverse effects of smoke exposure on bone by stimulating bone formation and inhibiting bone turnover and bone resorption. PMID:22713117
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Gao, Shu-guang; Cheng, Ling; Li, Kang-hua; Liu, Wen-He; Xu, Mai; Jiang, Wei; Wei, Li-Cheng; Zhang, Fang-jie; Xiao, Wen-feng; Xiong, Yi-lin; Tian, Jian; Zeng, Chao; Sun, Jin-peng; Xie, Qiang; Lei, Guang-hua
2012-06-19
Epimedii herba is one of the most frequently used herbs in formulas that are prescribed for the treatment of osteoporosis in China and its main constituent is Epimedium pubescen flavonoid (EPF). However, it is unclear whether EPF during chronic exposure to cigarette smoke may have a protective influence on the skeleton. The present study investigated the effect of EPF on bone mineral status and bone turnover in a rat model of human relatively high exposure to cigarette smoke. Fifty male Wistar rats were randomized into five groups: controls, passive smoking groups and passive smoking rats administered EPF at three dosage levels (75, 150 or 300 mg/kg/day) in drinking water for 4 months. A rat model of passive smoking was prepared by breeding male rats in a cigarette-smoking box. Bone mineral content (BMC), bone mineral density (BMD), bone turnover markers, bone histomorphometric parameters and biomechanical properties were examined. Smoke exposure decreased BMC and BMD, increased bone turnover (inhibited bone formation and stimulated its resorption), affected bone histomorphometry (increased trabecular separation and osteoclast surface per bone surface; decreased trabecular bone volume, trabecular thickness, trabecular number, cortical thickness, bone formation rate and osteoblast surface per bone surface), and reduced mechanical properties. EPF supplementation during cigarette smoke exposure prevented smoke-induced changes in bone mineral status and bone turnover. The results suggest that EPF can prevent the adverse effects of smoke exposure on bone by stimulating bone formation and inhibiting bone turnover and bone resorption.
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Binkley, N; Krueger, D
2000-05-01
Animal, human, and in vitro data all indicate that excess vitamin A stimulates bone resorption and inhibits bone formation. This combination would be expected to produce bone loss and to contribute to osteoporosis development and may occur with relatively low vitamin A intake. It is possible that unappreciated hypervitaminosis A contributes to osteoporosis pathogenesis.
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Partial Loss of Anabolic Effect of Prostaglandin E(sub 2) on Bone After Its Withdrawal in Rats
NASA Technical Reports Server (NTRS)
Ke, H. Z.; Li, X. J.; Jee, W. S. S.
1991-01-01
The object of this study was to determine the fate of PGE(sub 2)-induced new bone mass after withdrawal of PGE(sub 2) administration. Seven-month-old male Sprague-Dawley rats were given subcutaneous injections of 1, 3, and 6 mg PGE(sub 2),/kg/d for 60 days and then withdrawn for 60 and 120 days. Histomorphometric analyses were performed on double fluorescent labeled undecalcified proximal tibial bone specimens. After 60 days of PGE(sub 2) treatment, a new steady state of increased trabecular bone area (+67% and +81% with 3 and 6 mg PGE(sub 2)/kg/d) from woven bone and stimulated lamellar bone formation, elevated bone turnover, and shortened remodeling periods were achieved compared to age-matched controls. In contrast, after 60 and 120 days withdrawal of PGE(sub 2), a new steady state characterized by less trabecular bone area (+40% to +60% of controls with 3 and 6 mg/kg/d doses), normal lamellar bone formation, no woven bone formation from controls, and eroded surface greater than those seen in controls and previously in 60-day PGE(sub 2) treated rats. The decrease in new bone mass after withdrawal of PGE(sub 2), was due to a further elevation of bone resorption above that induced by the PGE(sub 2) treatment and a reduction in PGE(sub 2), stimulated bone formation activities. Although there is more trabecular bone than in controls after 120 days withdrawal of PGE(sub 2), we postulate that the skeletal adaptation to mechanical usage will eventually reduce the bone mass to control levels. Thus, it is conservative to conclude that the anabolic effect of PGE(sub 2) was dependent upon continuous daily administration of PGE(sub 2) in these older rats.
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Partial Loss of Anabolic Effect of Prostaglandin E2 on Bone After Its Withdrawal in Rats
NASA Technical Reports Server (NTRS)
Ke, H. Z.; Li, X. J.; Jee, Webster S. S.
1991-01-01
The object of this study was to determine the fate of PGE(sub 2)-induced new bone mass after withdrawal of PGE(sub 2) administration. Seven-month-old male Sprague-Dawley rats were given subcutaneous injections of 1, 3, and 6 mg PGE(sub 2)/kg/d for 60 days and then withdrawn for 60 and 120 days. Histomorphometric analyses were performed on double fluorescent labeled undecalcified proximal tibial bone specimens. After 60 days of PGE(sub 2) treatment, a new steady state of increased trabecular bone area (+67% and +81% with 3 and 6 mg PGE(sub 2)/kg/d) from woven bone and stimulated lamellar bone formation, elevated bone turnover, and shortened remodeling periods were achieved compared to age-matched controls. In contrast, after 60 and 120 days withdrawal of PGE(sub 2), a new steady state characterized by less trabecular bone area (+40% to +60% of controls with 3 and 6 mg/kg/d doses), normal lamellar bone formation, no woven bone formation from controls, and eroded surface greater than those seen in controls and previously in 60-day PGE(sub 2) treated rats. The decrease in new bone mass after withdrawal of PGE(sub 2) was due to a further elevation of bone resorption above that induced by the PGE(sub 2) treatment and a reduction in PGE(sub 2) stimulated bone formation activities. Although there is more trabecular bone than in controls after 120 days' withdrawal of PGE(sub 2), we postulate that the skeletal adaptation to mechanical usage will eventually reduce the bone mass to control levels. Thus, it is conservative to conclude that the anabolic effect of PGE(sub 2) was dependent upon continuous daily administration of PGE(sub 2) in these older rats.
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Trabecular bone adaptation to low-magnitude high-frequency loading in microgravity.
Torcasio, Antonia; Jähn, Katharina; Van Guyse, Maarten; Spaepen, Pieter; Tami, Andrea E; Vander Sloten, Jos; Stoddart, Martin J; van Lenthe, G Harry
2014-01-01
Exposure to microgravity causes loss of lower body bone mass in some astronauts. Low-magnitude high-frequency loading can stimulate bone formation on earth. Here we hypothesized that low-magnitude high-frequency loading will also stimulate bone formation under microgravity conditions. Two groups of six bovine cancellous bone explants were cultured at microgravity on a Russian Foton-M3 spacecraft and were either loaded dynamically using a sinusoidal curve or experienced only a static load. Comparable reference groups were investigated at normal gravity. Bone structure was assessed by histology, and mechanical competence was quantified using μCT and FE modelling; bone remodelling was assessed by fluorescent labelling and secreted bone turnover markers. Statistical analyses on morphometric parameters and apparent stiffness did not reveal significant differences between the treatment groups. The release of bone formation marker from the groups cultured at normal gravity increased significantly from the first to the second week of the experiment by 90.4% and 82.5% in response to static and dynamic loading, respectively. Bone resorption markers decreased significantly for the groups cultured at microgravity by 7.5% and 8.0% in response to static and dynamic loading, respectively. We found low strain magnitudes to drive bone turnover when applied at high frequency, and this to be valid at normal as well as at microgravity. In conclusion, we found the effect of mechanical loading on trabecular bone to be regulated mainly by an increase of bone formation at normal gravity and by a decrease in bone resorption at microgravity. Additional studies with extended experimental time and increased samples number appear necessary for a further understanding of the anabolic potential of dynamic loading on bone quality and mechanical competence.
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Low dose PTH improves metaphyseal bone healing more when muscles are paralyzed.
Sandberg, Olof; Macias, Brandon R; Aspenberg, Per
2014-06-01
Stimulation of bone formation by PTH is related to mechanosensitivity. The response to PTH treatment in intact bone could therefore be blunted by unloading. We studied the effects of mechanical loading on the response to PTH treatment in bone healing. Most fractures occur in the metaphyses, therefor we used a model for metaphyseal bone injury. One hind leg of 20 male SD rats was unloaded via intramuscular botulinum toxin injections. Two weeks later, the proximal unloaded tibia had lost 78% of its trabecular contents. At this time-point, the rats received bilateral proximal tibiae screw implants. Ten of the 20 rats were given daily injections of 5 μg/kg PTH (1-34). After two weeks of healing, screw fixation was measured by pull-out, and microCT of the distal femur cancellous compartment was performed. Pull-out force provided an estimate for cancellous bone formation after trauma. PTH more than doubled the pull-out force in the unloaded limbs (from 14 to 30 N), but increased it by less than half in the loaded ones (from 30 to 44 N). In relative terms, PTH had a stronger effect on pull-out force in unloaded bone than in loaded bone (p=0.03). The results suggest that PTH treatment for stimulation of bone healing does not require simultaneous mechanical stimulation. Copyright © 2014 Elsevier Inc. All rights reserved.
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Yamaguchi, Masayoshi
2016-10-01
Bone homeostasis is maintained through a balance between osteoblastic bone formation and osteoclastic bone resorption. Bone loss with aging is induced by decreasing in osteoblastic bone formation and increasing in osteoclastic bone resorption, thereby leading to osteoporosis. Osteoporosis with its accompanying decrease in bone mass is widely recognized as a major public heath problem. Pharmacologic and nutritional factors may play a role in the prevention and treatment of bone loss with aging. p-Hydroxycinnamic acid (HCA), which stimulates bone mineralization in mouse bone tissues in vitro, has been found to be present in the leafstalk of wasabi (Wasabi japonica MATSUM) among various food and plants. Other phenolic acids including cinnamic acid, ferulic acid, caffeic acid and 3,4-dimethoxycinnamic acid did not have osteogenic effects. HCA was demonstrated to stimulate osteoblastic bone formation and suppresses osteoclastic bone resorption in vitro by antagonizing activation of the nuclear factor kappa B. Oral administration of HCA was found to exhibit restorative effects on bone loss induced by ovariectomy and diabetic states, supporting a role in the treatment of osteoporosis. Moreover, HCA was demonstrated to prevent the suppressed osteoblastic mineralization and the enhanced osteoclastogenesis in mouse bone marrow cells cocultured with bone metastatic MDA-MB-231 human breast cancer cells in vitro. The botanical molecule HCA, as a new osteogenic agent, is suggested to play a role in the treatment of cancer bone metastases. This review will discuss an advanced recent finding that HCA may be a useful agent to treat bone metabolic disorder.
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Bioactive scaffold for bone tissue engineering: An in vivo study
NASA Astrophysics Data System (ADS)
Livingston, Treena Lynne
Massive bone loss of the proximal femur is a common problem in revision cases of total hip implants. Allograft is typically used to reconstruct the site for insertion of the new prosthesis. However, for long term fixation and function, it is desirable that the allograft becomes fully replaced by bone tissue and aids in the regeneration of bone to that site. However, allograft use is typically associated with delayed incorporation and poor remodeling. Due to these profound limitations, alternative approaches are needed. Tissue engineering is an attractive approach to designing improved graft materials. By combining osteogenic activity with a resorbable scaffold, bone formation can be stimulated while providing structure and stability to the limb during incorporation and remodeling of the scaffold. Porous, surface modified bioactive ceramic scaffolds (pSMC) have been developed which stimulate the expression of the osteoblastic phenotype and production of bone-like tissue in vitro. The scaffold and two tissue-engineered constructs, osteoprogenitor cells seeded onto scaffolds or cells expanded in culture to form bone tissue on the scaffolds prior to implantation, were investigated in a long bone defect model. The rate of incorporation was assessed. Both tissue-engineered constructs stimulated bone formation and comparable repair at 2 weeks. In a rat femoral window defect model, bone formation increased over time for all groups in concert with scaffold resorption, leading to a 40% increase in bone and 40% reduction of the scaffold in the defect by 12 weeks. Both tissue-engineered constructs enhanced the rate of mechanical repair of long bones due to better bony union with the host cortex. Long bones treated with tissue engineered constructs demonstrated a return in normal torsional properties by 4 weeks as compared to 12 weeks for long bones treated with pSMC. Culture expansion of cells to produce bone tissue in vitro did not accelerate incorporation over the treatment with cells seeded at the time of surgery. Porous, surface modified bioactive ceramic is a promising scaffold material for tissue-engineered bone repair. Bone formation and scaffold resorption act in concert for maintenance and improvement of the structural properties of the long bones over time. As determined histomorphometrically and mechanically, the rate of incorporation of the scaffold was enhanced with the tissue-engineered constructs.
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Suzuki, Selly Sayuri; Garcez, Aguinaldo Silva; Suzuki, Hideo; Ervolino, Edilson; Moon, Won; Ribeiro, Martha Simões
2016-12-01
This study evaluated the biological effects of low-level laser therapy (LLLT) on bone remodeling, tooth displacement and root resorption, occurred during the orthodontic tooth movement. Upper first molars of a total of sixty-eight male rats were subjected to orthodontic tooth movement and euthanized on days 3, 6, 9, 14 and 21 days and divided as negative control, control and LLLT group. Tooth displacement and histomorphometric analysis were performed in all animals; scanning electron microscopy analysis was done on days 3, 6 and 9, as well as the immunohistochemistry analysis of RANKL/OPG and TRAP markers. Volumetric changes in alveolar bone were analyzed using MicroCT images on days 14 and 21. LLLT influenced bone resorption by increasing the number of TRAP-positive osteoclasts and the RANKL expression at the compression side. This resulted in less alveolar bone and hyalinization areas on days 6, 9 and 14. LLLT also induced less bone volume and density, facilitating significant acceleration of tooth movement and potential reduction in root resorption besides stimulating bone formation at the tension side by enhancing OPG expression, increasing trabecular thickness and bone volume on day 21. Taken together, our results indicate that LLLT can stimulate bone remodeling reducing root resorption in a rat model. LLLT improves tooth movement via bone formation and bone resorption in a rat model. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Wu, Chi-Ming; Chen, Po-Chun; Li, Te-Mao; Fong, Yi-Chin; Tang, Chih-Hsin
2013-10-24
Si-Wu-Tang (SWT), a Traditional Chinese Medicine (TCM) formula, is widely used for the treatment of gynopathies diseases such as menstrual discomfort, climacteric syndrome, dysmenorrhea, and other estrogen-related diseases. Recent studies have shown that SWT can treat primary dysmenorrhea, have anti-pruritic anti-inflammatory effects, and protect against radiation-induced bone marrow damage in an animal model. It has been reported that anti-inflammatory and anti-oxidant agents have the potential to treat osteoporosis by increasing bone formation and/or suppressing bone resorption. However, the effect of SWT on bone cell function has not yet been reported. Alkaline phosphatase (ALP), bone morphogenetic proteins (BMP)-2, and osteopontin (OPN) mRNA expression was analyzed by qPCR. The mechanism of action of SWT extract was investigated using western blotting. The in vivo anti-osteoporotic effect of SWT extract was assessed in ovariectomized mice. Here, we report that SWT increases ALP, BMP-2, and OPN expression as well as bone mineralization. In addition, we show that the PI3K, Akt, and NF-κB signaling pathways may be involved in the SWT-mediated increase in gene expression and bone mineralization. Notably, treatment of mice with SWT extract prevented bone loss induced by ovariectomy in vivo. SWT may be used to stimulate bone formation for the treatment of osteoporosis.
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Numerical simulation of electrically stimulated osteogenesis in dental implants.
Vanegas-Acosta, J C; Garzón-Alvarado, D A; Lancellotti, V
2014-04-01
Cell behavior and tissue formation are influenced by a static electric field (EF). Several protocols for EF exposure are aimed at increasing the rate of tissue recovery and reducing the healing times in wounds. However, the underlying mechanisms of the EF action on cells and tissues are still a matter of research. In this work we introduce a mathematical model for electrically stimulated osteogenesis at the bone-dental implant interface. The model describes the influence of the EF in the most critical biological processes leading to bone formation at the bone-dental implant interface. The numerical solution is able to reproduce the distribution of spatial-temporal patterns describing the influence of EF during blood clotting, osteogenic cell migration, granulation tissue formation, displacements of the fibrillar matrix, and formation of new bone. In addition, the model describes the EF-mediated cell behavior and tissue formation which lead to an increased osteogenesis in both smooth and rough implant surfaces. Since numerical results compare favorably with experimental evidence, the model can be used to predict the outcome of using electrostimulation in other types of wounds and tissues. Copyright © 2013 Elsevier B.V. All rights reserved.
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A soluble bone morphogenetic protein type IA receptor increases bone mass and bone strength
Baud’huin, Marc; Solban, Nicolas; Cornwall-Brady, Milton; Sako, Dianne; Kawamoto, Yoshimi; Liharska, Katia; Lath, Darren; Bouxsein, Mary L.; Underwood, Kathryn W.; Ucran, Jeffrey; Kumar, Ravindra; Pobre, Eileen; Grinberg, Asya; Seehra, Jasbir; Canalis, Ernesto; Pearsall, R. Scott; Croucher, Peter I.
2012-01-01
Diseases such as osteoporosis are associated with reduced bone mass. Therapies to prevent bone loss exist, but there are few that stimulate bone formation and restore bone mass. Bone morphogenetic proteins (BMPs) are members of the TGFβ superfamily, which act as pleiotropic regulators of skeletal organogenesis and bone homeostasis. Ablation of the BMPR1A receptor in osteoblasts increases bone mass, suggesting that inhibition of BMPR1A signaling may have therapeutic benefit. The aim of this study was to determine the skeletal effects of systemic administration of a soluble BMPR1A fusion protein (mBMPR1A–mFc) in vivo. mBMPR1A–mFc was shown to bind BMP2/4 specifically and with high affinity and prevent downstream signaling. mBMPR1A–mFc treatment of immature and mature mice increased bone mineral density, cortical thickness, trabecular bone volume, thickness and number, and decreased trabecular separation. The increase in bone mass was due to an early increase in osteoblast number and bone formation rate, mediated by a suppression of Dickkopf-1 expression. This was followed by a decrease in osteoclast number and eroded surface, which was associated with a decrease in receptor activator of NF-κB ligand (RANKL) production, an increase in osteoprotegerin expression, and a decrease in serum tartrate-resistant acid phosphatase (TRAP5b) concentration. mBMPR1A treatment also increased bone mass and strength in mice with bone loss due to estrogen deficiency. In conclusion, mBMPR1A–mFc stimulates osteoblastic bone formation and decreases bone resorption, which leads to an increase in bone mass, and offers a promising unique alternative for the treatment of bone-related disorders. PMID:22761317
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Merolli, Antonio; Fung, Stephanie; Murthy, N Sanjeeva; Pashuck, E Thomas; Mao, Yong; Wu, Xiaohuan; Steele, Joseph A M; Martin, Daniel; Moghe, Prabhas V; Bromage, Timothy; Kohn, Joachim
2018-03-21
Osteoclasts are large multinucleated giant cells that actively resorb bone during the physiological bone turnover (BTO), which is the continuous cycle of bone resorption (by osteoclasts) followed by new bone formation (by osteoblasts). Osteoclasts secrete chemotactic signals to recruit cells for regeneration of vasculature and bone. We hypothesize that a biomaterial that attracts osteoclasts and re-establishes BTO will induce a better healing response than currently used bone graft materials. While the majority of bone regeneration efforts have focused on maximizing bone deposition, the novelty in this approach is the focus on stimulating osteoclastic resorption as the starter for BTO and its concurrent new vascularized bone formation. A biodegradable tyrosine-derived polycarbonate, E1001(1k), was chosen as the polymer base due to its ability to support bone regeneration in vivo. The polymer was functionalized with a RGD peptide or collagen I, or blended with β-tricalcium phosphate. Osteoclast attachment and early stages of active resorption were observed on all substrates. The transparency of E1001(1k) in combination with high resolution confocal imaging enabled visualization of morphological features of osteoclast activation such as the formation of the "actin ring" and the "ruffled border", which previously required destructive forms of imaging such as transmission electron microscopy. The significance of these results is twofold: (1) E1001(1k) is suitable for osteoclast attachment and supports osteoclast maturation, making it a base polymer that can be further modified to optimize stimulation of BTO and (2) the transparency of this polymer makes it a suitable analytical tool for studying osteoclast behavior.
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Carbon nanotubes with high bone-tissue compatibility and bone-formation acceleration effects.
Usui, Yuki; Aoki, Kaoru; Narita, Nobuyo; Murakami, Narumichi; Nakamura, Isao; Nakamura, Koichi; Ishigaki, Norio; Yamazaki, Hiroshi; Horiuchi, Hiroshi; Kato, Hiroyuki; Taruta, Seiichi; Kim, Yoong Ahm; Endo, Morinobu; Saito, Naoto
2008-02-01
Carbon nanotubes (CNTs) have been used in various fields as composites with other substances or alone to develop highly functional materials. CNTs hold great interest with respect to biomaterials, particularly those to be positioned in contact with bone such as prostheses for arthroplasty, plates or screws for fracture fixation, drug delivery systems, and scaffolding for bone regeneration. Accordingly, bone-tissue compatibility of CNTs and CNT influence on bone formation are important issues, but the effects of CNTs on bone have not been delineated. Here, it is found that multi-walled CNTs adjoining bone induce little local inflammatory reaction, show high bone-tissue compatibility, permit bone repair, become integrated into new bone, and accelerate bone formation stimulated by recombinant human bone morphogenetic protein-2 (rhBMP-2). This study provides an initial investigational basis for CNTs in biomaterials that are used adjacent to bone, including uses to promote bone regeneration. These findings should encourage development of clinical treatment modalities involving CNTs.
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Decco, Oscar A; Beltrán, Víctor; Zuchuat, Jésica I; Cura, Andrea C; Lezcano, María F; Engelke, Wilfried
2015-07-30
Bone augmentation is a subject of intensive investigation in regenerative bone medicine and constitutes a clinical situation in which autogenous bone grafts or synthetic materials are used to aid new bone formation. Based on a non-critical defect, Co-Cr barrier membranes were placed on six adult Fauve de Bourgogne rabbits, divided into two groups: whole blood and PRP. Three densitometric controls were performed during the experiment. The animals were euthanized at 30, 45, 60, and 110 days. The presence of newly formed bone was observed. Samples for histological studies were taken from the augmentation center. External and internal bone tissue augmentation was observed in almost all cases. Significant differences between PRP- and whole blood-stimulated bone augmentation were not observed. At 60 days, bones with PRP presented higher angiogenesis, which may indicate more proliferation and cellular activity. PRP activates the bone regeneration process under optimized conditions by stimulation of osteoblast proliferation after six weeks, when a significant difference in cellular activity was observed. Membranes could stimulate bone augmentation at the site of placement and in the surrounding areas.
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A New Piezoelectric Actuator Induces Bone Formation In Vivo: A Preliminary Study
Reis, Joana; Frias, Clara; Canto e Castro, Carlos; Botelho, Maria Luísa; Marques, António Torres; Simões, José António Oliveira; Capela e Silva, Fernando; Potes, José
2012-01-01
This in vivo study presents the preliminary results of the use of a novel piezoelectric actuator for orthopedic application. The innovative use of the converse piezoelectric effect to mechanically stimulate bone was achieved with polyvinylidene fluoride actuators implanted in osteotomy cuts in sheep femur and tibia. The biological response around the osteotomies was assessed through histology and histomorphometry in nondecalcified sections and histochemistry and immunohistochemistry in decalcified sections, namely, through Masson's trichrome, and labeling of osteopontin, proliferating cell nuclear antigen, and tartrate-resistant acid phosphatase. After one-month implantation, total bone area and new bone area were significantly higher around actuators when compared to static controls. Bone deposition rate was also significantly higher in the mechanically stimulated areas. In these areas, osteopontin increased expression was observed. The present in vivo study suggests that piezoelectric materials and the converse piezoelectric effect may be used to effectively stimulate bone growth. PMID:22701304
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Johnson, Jared S; Meliton, Vicente; Kim, Woo Kyun; Lee, Kwang-Bok; Wang, Jeffrey C; Nguyen, Khanhlinh; Yoo, Dongwon; Jung, Michael E; Atti, Elisa; Tetradis, Sotirios; Pereira, Renata C; Magyar, Clara; Nargizyan, Taya; Hahn, Theodore J; Farouz, Francine; Thies, Scott; Parhami, Farhad
2011-06-01
Stimulation of bone formation by osteoinductive materials is of great clinical importance in spinal fusion surgery, repair of bone fractures, and in the treatment of osteoporosis. We previously reported that specific naturally occurring oxysterols including 20(S)-hydroxycholesterol (20S) induce the osteogenic differentiation of pluripotent mesenchymal cells, while inhibiting their adipogenic differentiation. Here we report the characterization of two structural analogues of 20S, Oxy34 and Oxy49, which induce the osteogenic and inhibit the adipogenic differentiation of bone marrow stromal cells (MSC) through activation of Hedgehog (Hh) signaling. Treatment of M2-10B4 MSC with Oxy34 or Oxy49 induced the expression of osteogenic differentiation markers Runx2, Osterix (Osx), alkaline phosphatase (ALP), bone sialoprotein (BSP), and osteocalcin (OCN), as well as ALP enzymatic activity and robust mineralization. Treatment with oxysterols together with PPARγ activator, troglitazone (Tro), inhibited mRNA expression for adipogenic genes PPARγ, LPL, and aP2, and inhibited the formation of adipocytes. Efficacy of Oxy34 and Oxy49 in stimulating bone formation in vivo was assessed using the posterolateral intertransverse process rat spinal fusion model. Rats receiving collagen implants with Oxy 34 or Oxy49 showed comparable osteogenic efficacy to BMP2/collagen implants as measured by radiography, MicroCT, and manual inspection. Histological analysis showed trabecular and cortical bone formation by oxysterols and rhBMP2 within the fusion mass, with robust adipogenesis in BMP2-induced bone and significantly less adipocytes in oxysterol-induced bone. These data suggest that Oxy34 and Oxy49 are effective novel osteoinductive molecules and may be suitable candidates for further development and use in orthopedic indications requiring local bone formation. Copyright © 2011 Wiley-Liss, Inc.
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Sinder, Benjamin P.; Salemi, Joseph D.; Ominsky, Michael S.; Caird, Michelle S.; Marini, Joan C.; Kozloff, Kenneth M.
2014-01-01
Osteogenesis imperfecta (OI) is a heritable collagen-related bone dysplasia, characterized by brittle bones with increased fracture risk that presents most severely in children. Anti-resorptive bisphosphonates are frequently used to treat pediatric OI and controlled clinical trials have shown bisphosphonate therapy improves vertebral outcomes but has little benefit on long bone fracture rate. New treatments which increase bone mass throughout the pediatric OI skeleton would be beneficial. Sclerostin antibody (Scl-Ab) is a potential candidate anabolic therapy for pediatric OI and functions by stimulating osteoblastic bone formation via the canonical wnt signaling pathway. To explore the effect of Scl-Ab on the rapidly growing OI skeleton, we treated rapidly growing 3 week old Brtl/+ mice, harboring a typical heterozygous OI-causing Gly->Cys substitution on col1a1, for 5 weeks with Scl-Ab. Scl-Ab had anabolic effects in Brtl/+ and led to new cortical bone formation and increased cortical bone mass. This anabolic action resulted in improved mechanical strength to WT Veh levels without altering the underlying brittle nature of the material. While Scl-Ab was anabolic in trabecular bone of the distal femur in both genotypes, the effect was less strong in these rapidly growing Brtl/+ mice compared to WT. In conclusion, Scl-Ab was able to stimulate bone formation in a rapidly growing Brtl/+ murine model of OI, and represents a potential new therapy to improve bone mass and reduce fracture risk in pediatric OI. PMID:25445450
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Role of nutritional zinc in the prevention of osteoporosis.
Yamaguchi, Masayoshi
2010-05-01
Zinc is known as an essential nutritional factor in the growth of the human and animals. Bone growth retardation is a common finding in various conditions associated with dietary zinc deficiency. Bone zinc content has been shown to decrease in aging, skeletal unloading, and postmenopausal conditions, suggesting its role in bone disorder. Zinc has been demonstrated to have a stimulatory effect on osteoblastic bone formation and mineralization; the metal directly activates aminoacyl-tRNA synthetase, a rate-limiting enzyme at translational process of protein synthesis, in the cells, and it stimulates cellular protein synthesis. Zinc has been shown to stimulate gene expression of the transcription factors runt-related transcription factor 2 (Runx2) that is related to differentiation into osteoblastic cells. Moreover, zinc has been shown to inhibit osteoclastic bone resorption due to inhibiting osteoclast-like cell formation from bone marrow cells and stimulating apoptotic cell death of mature osteoclasts. Zinc has a suppressive effect on the receptor activator of nuclear factor (NF)-kappaB ligand (RANKL)-induced osteoclastogenesis. Zinc transporter has been shown to express in osteoblastic and osteoclastic cells. Zinc protein is involved in transcription. The intake of dietary zinc causes an increase in bone mass. beta-Alanyl-L: -histidinato zinc (AHZ) is a zinc compound, in which zinc is chelated to beta-alanyl-L: -histidine. The stimulatory effect of AHZ on bone formation is more intensive than that of zinc sulfate. Zinc acexamate has also been shown to have a potent-anabolic effect on bone. The oral administration of AHZ or zinc acexamate has the restorative effect on bone loss under various pathophysiologic conditions including aging, skeletal unloading, aluminum bone toxicity, calcium- and vitamin D-deficiency, adjuvant arthritis, estrogen deficiency, diabetes, and fracture healing. Zinc compounds may be designed as new supplementation factor in the prevention and therapy of osteoporosis.
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Kiuru, Maija; Solomon, Jason; Ghali, Bassem; van der Meulen, Marjolein; Crystal, Ronald G; Hidaka, Chisa
2009-01-01
Bone formation and remodeling involve coordinated interactions between osteoblasts and osteoclasts through signaling networks involving a variety of molecular pathways. We hypothesized that overexpression of Sonic hedgehog (Shh), a morphogen with a crucial role in skeletal development, would stimulate osteoblastogenesis and bone formation in adult animals in vivo. Systemic administration of adenovirus expressing the N-terminal form of Shh into adult mice resulted in a primary increase in osteoblasts and their precursors. Surprisingly, however, this was associated with altered trabecular morphology, decreased bone volume, and decreased compressive strength in the vertebrae. Whereas no change was detected in the number of osteoclast precursors, bone marrow stromal cells from Shh-treated mice showed enhanced osteoclastogenic potential in vitro. These effects were mediated by the PTH/PTH-related protein (PTHrP) pathway as evidenced by increased sensitivity to PTH stimulation and upregulation of the PTH/PTHrP receptor (PPR). Together, these data show that Shh has stimulatory effects on osteoprogenitors and osteoblasts in adult animals in vivo, which results in bone remodeling and reduced bone strength because of a secondary increase in osteoclastogenesis. PMID:19338448
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Sclerostin and Dickkopf-1 as therapeutic targets in bone diseases.
Ke, Hua Zhu; Richards, William G; Li, Xiaodong; Ominsky, Michael S
2012-10-01
The processes of bone growth, modeling, and remodeling determine the structure, mass, and biomechanical properties of the skeleton. Dysregulated bone resorption or bone formation may lead to metabolic bone diseases. The Wnt pathway plays an important role in bone formation and regeneration, and expression of two Wnt pathway inhibitors, sclerostin and Dickkopf-1 (DKK1), appears to be associated with changes in bone mass. Inactivation of sclerostin leads to substantially increased bone mass in humans and in genetically manipulated animals. Studies in various animal models of bone disease have shown that inhibition of sclerostin using a monoclonal antibody (Scl-Ab) increases bone formation, density, and strength. Additional studies show that Scl-Ab improves bone healing in models of bone repair. Inhibition of DKK1 by monoclonal antibody (DKK1-Ab) stimulates bone formation in younger animals and to a lesser extent in adult animals and enhances fracture healing. Thus, sclerostin and DKK1 are emerging as the leading new targets for anabolic therapies to treat bone diseases such as osteoporosis and for bone repair. Clinical trials are ongoing to evaluate the effects of Scl-Ab and DKK1-Ab in humans for the treatment of bone loss and for bone repair.
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Pharmacological management of osteogenesis
Nardone, Valeria; D'Asta, Federica; Brandi, Maria Luisa
2014-01-01
Osteogenesis and bone remodeling are complex biological processes that are essential for the formation of new bone tissue and its correct functioning. When the balance between bone resorption and formation is disrupted, bone diseases and disorders such as Paget's disease, fibrous dysplasia, osteoporosis and fragility fractures may result. Recent advances in bone cell biology have revealed new specific targets for the treatment of bone loss that are based on the inhibition of bone resorption by osteoclasts or the stimulation of bone formation by osteoblasts. Bisphosphonates, antiresorptive agents that reduce bone resorption, are usually recommended as first-line therapy in women with postmenopausal osteoporosis. Numerous studies have shown that bisphosphonates are able to significantly reduce the risk of femoral and vertebral fractures. Other antiresorptive agents indicated for the treatment of osteoporosis include selective estrogen receptor modulators, such as raloxifene. Denosumab, a human monoclonal antibody, is another antiresorptive agent that has been approved in Europe and the USA. This agent blocks the RANK/RANKL/OPG system, which is responsible for osteoclastic activation, thus reducing bone resorption. Other approved agents include bone anabolic agents, such as teriparatide, a recombinant parathyroid hormone that improves bone microarchitecture and strength, and strontium ranelate, considered to be a dual-action drug that acts by both osteoclastic inhibition and osteoblastic stimulation. Currently, anti-catabolic drugs that act through the Wnt-β catenin signaling pathway, serving as Dickkopf-related protein 1 inhibitors and sclerostin antagonists, are also in development. This concise review provides an overview of the drugs most commonly used for the control of osteogenesis in bone diseases. PMID:24964310
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NASA Technical Reports Server (NTRS)
Halloran, B. P.; Bikle, D. D.; Harris, J.; Tanner, S.; Curren, T.; Morey-Holton, E.
1997-01-01
To determine whether the acute inhibition of bone formation and deficit in bone mineral induced by skeletal unloading can be prevented, we studied the effects of intermittent parathyroid hormone (PTH) administration (8 micrograms/100 g/day) on growing rats submitted to 8 days of skeletal unloading. Loss of weight bearing decreased periosteal bone formation by 34 and 51% at the tibiofibular junction and tibial midshaft, respectively, and reduced the normal gain in tibial mass by 35%. Treatment with PTH of normally loaded and unloaded animals increased mRNA for osteocalcin (+58 and +148%, respectively), cancellous bone volume in the proximal tibia (+41 and +42%, respectively), and bone formation at the tibiofibular junction (+27 and +27%, respectively). Formation was also stimulated at the midshaft in unloaded (+47%, p < 0.05), but not loaded animals (-3%, NS). Although cancellous bone volume was preserved in PTH-treated, unloaded animals, PTH did not restore periosteal bone formation to normal nor prevent the deficit in overall tibial mass induced by unloading. We conclude that the effects of PTH on bone formation are region specific and load dependent. PTH can prevent the decrease in cancellous bone volume and reduce the decrement in cortical bone formation induced by loss of weight bearing.
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Liu, Jess; Czernick, Drew; Lin, Shih-Chun; Alasmari, Abeer; Serge, Dibart; Salih, Erdjan
2013-09-01
Egg yolk phosvitin is one of the most highly phosphorylated extracellular matrix proteins known in nature with unique physico-chemical properties deemed to be critical during ex-vivo egg embryo development. We have utilized our unique live mouse calvarial bone organ culture models under conditions which dissociates the two bone remodeling stages, viz., resorption by osteoclasts and formation by osteoblasts, to highlight important and to date unknown critical biological functions of egg phosvitin. In our resorption model live bone cultures were grown in the absence of ascorbate and were stimulated by parathyroid hormone (PTH) to undergo rapid osteoclast formation/differentiation with bone resorption. In this resorption model native phosvitin potently inhibited PTH-induced osteoclastic bone resorption with simultaneous new osteoid/bone formation in the absence of ascorbate (vitamin C). These surprising and critical observations were extended using the bone formation model in the absence of ascorbate and in the presence of phosvitin which supported the above results. The results were corroborated by analyses for calcium release or uptake, tartrate-resistant acid phosphatase activity (marker for osteoclasts), alkaline phosphatase activity (marker for osteoblasts), collagen and hydroxyproline composition, and histological and quantitative histomorphometric evaluations. The data revealed that the discovered bioactivity of phosvitin mirrors that of ascorbate during collagen synthesis and the formation of new osteoid/bone. Complementing those studies use of the synthetic collagen peptide analog and cultured calvarial osteoblasts in conjunction with mass spectrometric analysis provided results that augmented the bone organ culture work and confirmed the capacity of phosvitin to stimulate differentiation of osteoblasts, collagen synthesis, hydroxyproline formation, and biomineralization. There are striking implications and interrelationships of this affect that relates to the evolutionary inactivation of the gene of an enzyme L-gulono-γ-lactone oxidase, which is involved in the final step of ascorbate biosynthesis, in many vertebrate species including passeriform birds, reptiles and teleost fish whose egg yolk contain phosvitin. These represent examples of how developing ex-vivo embryos of such species can achieve connective tissue and skeletal system formation in the absence of ascorbate. Copyright © 2013 Elsevier Inc. All rights reserved.
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Wade-Gueye, Ndéye Marième; Boudiffa, Maya; Laroche, Norbert; Vanden-Bossche, Arnaud; Fournier, Carole; Aubin, Jane E; Vico, Laurence; Lafage-Proust, Marie-Hélène; Malaval, Luc
2010-11-01
Bone sialoprotein (BSP) belongs to the small integrin-binding ligand, N-linked glycoprotein (SIBLING) family, whose members play multiple and distinct roles in the development, turnover, and mineralization of bone and dentin. The functions of BSP in bone remodeling are not yet well established. We previously showed that BSP knockout (BSP(-/-)) mice exhibit a higher trabecular bone volume, concomitant with lower bone remodeling, than wild-type (BSP(+/+)) mice. To determine whether bone turnover can be stimulated in the absence of BSP, we subjected BSP(+/+) and BSP(-/-) mice to catabolic [ovariectomy (OVX)] or anabolic (intermittent PTH administration) hormonal challenges. BSP(-/-) mice progressively develop hypocalcemia and high serum PTH between 2 and 4 months of age. Fifteen and 30 d after OVX, microtomography analysis showed a significant decrease of trabecular bone volume in tibiae of both genotypes. Histomorphometric parameters of bone formation and resorption were significantly increased by OVX. PTH treatment resulted in an increase of trabecular thickness and both bone formation and resorption parameters at all skeletal sites in both genotypes and a decrease of trabecular bone volume in tibiae of BSP(+/+) but not BSP(-/-) mice. PTH increased cortical thickness and bone area in BSP(+/+) but not BSP(-/-) mice and stimulated the bone formation rate specifically in the endosteum of BSP(+/+) mice and the periosteum of BSP(-/-) mice. PTH enhanced the expression of RANKL, MEPE, and DMP1 in both genotypes but increased OPG and OPN expression only in BSP(-/-) mice. In conclusion, despite the low basal turnover, both catabolic and anabolic challenges increase bone formation and resorption in BSP(-/-) mice, suggesting that compensatory pathways are operative in the skeleton of BSP-deficient mice. Although up-regulation of one or several other SIBLINGs is a possible mechanism, further studies are needed to analyze the interplay and cross-regulation involved in compensating for the absence of BSP.
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Effects of Amplitude and Frequency of Mechanical Vibration Stimulation on Cultured Osteoblasts
NASA Astrophysics Data System (ADS)
Shikata, Tetsuo; Shiraishi, Toshihiko; Morishita, Shin; Takeuchi, Ryohei; Saito, Tomoyuki
Mechanical stimulation to bones affects bone formation such as decrease of bone mass of astronauts under zero gravity, walking rehabilitation to bone fracture and fracture repair with ultrasound devices. Bone cells have been reported to sense and response to mechanical stimulation at cellular level morphologically and metabolically. In the view of mechanical vibrations, bone cells are deformed according to mechanical stimulation and their mechanical characteristics. In this study, sinusoidal inertia force was applied to cultured osteoblasts, which are a kind of bone cells, and effects of frequency and acceleration amplitude of mechanical vibration on the cells were investigated in respect of the cell proliferation, bone matrix generation and alkaline phosphatase (ALP) gene expression. The results to be obtained are as follows. The significant difference of cell density and bone mass generation between the non-vibrating and vibrating groups is found. ALP gene expression shows a peak to frequency at 50 Hz and the value of it is approximately 4.5 times as high as that of the non-vibrating group in the case of the acceleration amplitude of 0.5 G. ALP gene expression at 0.5 G is significantly larger than at 0, 0.125 or 0.25 G in the case of the frequency of 50 Hz.
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Chung, Hwa-Jin; Kyung Kim, Won; Joo Park, Hyen; Cho, Lan; Kim, Me-Riong; Kim, Min Jeong; Shin, Joon-Shik; Ho Lee, Jin; Ha, In-Hyuk; Kook Lee, Sang
2016-02-17
Harpagide, an iridoid glucoside, is a constituent of the root of Harpagophytum procumbens var. sublobatum (Engl.) Stapf, Devil's claw which has been used in patients with osteoarthritis (OA). In the present study, we investigated the anti-osteoporotic potential of harpagide and its underlying mechanism of action in in vitro cell culture and in vivo bone loss animal models. Harpagide was obtained from the alkalic hydrolysis of harpagoside, a major constituent of H. procumbens var. sublobatum Analysis of biomarkers for bone formation in osteoblastic MC3T3-E1 cells and bone resorption in osteoclast cells derived from mouse bone marrow cells was performed to evaluate the mechanism of action. The protective activity of harpagide against bone loss was also evaluated in ovariectomized (OVX) mouse model. Harpagide improved bone properties by stimulating the process of differentiation and maturation of osteoblast cells and suppressing the process of RANKL-induced differentiation of osteoclast cells. In OVX-induced bone loss mouse model, oral administration of harpagide significantly improved recovery of bone mineral density, trabecular bone volume, and trabecular number in the femur. Harpagide also prevented increase of trabecular separation and structure model index induced by OVX. Harpagide effectively inhibited the serum levels of biochemical markers of bone loss, including alkaline phosphatase, osteocalcin, C-terminal telopeptide, and tartrate-resistant acid phosphatase. Taken together, the present study demonstrates that harpagide has a potential for prevention of bone loss in OVX mice by regulating the stimulation of osteoblast differentiation and the suppression of osteoclast formation. Therefore, these findings suggest that harpagide might serve as a bioactive compound derived from H. procumbens var. sublobatum for improvement of age-dependent bone destruction disease. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
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Rosen, J; Negro-Vilar, A
2002-03-01
A novel approach to the treatment of osteoporosis in men, and possibly women, is the development of selective androgen receptor modulators (SARMs) that can stimulate formation of new bone with substantially diminished proliferative activity in the prostate, as well as reduced virilizing activity in women. Over the last several years, we have developed a program to discover and develop novel, non-steroidal, orally-active selective androgen receptor modulators (SARMs) that provide improved therapeutic benefits and reduce risk and side effects. In recent studies, we have used a skeletally mature orchiectomized (ORX) male rat as an animal model of male hypogonadism for assessing the efficacy of LGD2226, a nonsteroidal, non-aromatizable, and non-5alpha-reducible SARM. We assessed the activity of LGD2226 on bone turnover, bone mass and bone strength, and also evaluated the effects exerted on classic androgen-dependent targets, such as prostate, seminal vesicles and muscle. A substantial loss of bone density was observed in ORX animals, and this loss was prevented by SARMs, as well as standard androgens. Biochemical markers of bone turnover revealed an early increase of bone resorption in androgen-deficient rats that was repressed in ORX animals treated with the oral SARM, LGD2226, during a 4-month treatment period. Differences in architectural properties and bone strength were detected by histomorphometric and mechanical analyses, demonstrating beneficial effects of LGD2226 on bone quality in androgen-deficient rats. Histomorphometric analysis of cortical bone revealed distinct anabolic activity of LGD2226 in periosteal bone. LGD2226 was able to prevent bone loss and maintain bone quality in ORX rats by stimulating bone formation, while also inhibiting bone turnover. LGD2226 also exerted anabolic activity on the levator ani muscle. Taken together, these results suggest that orally-active, non-steroidal SARMs may be useful therapeutics for both muscle and bone in elderly hypogonadal men through their anabolic activities. Since SARMs both prevent bone loss, and also stimulate formation of new bone, they may have significant advantages relative to currently used anti-resorptive therapies. Coupled with their activity in muscle and their ability to maintain or restore libido, they offer new therapeutic approaches for male and female hormone replacement.
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Sinder, Benjamin P; Salemi, Joseph D; Ominsky, Michael S; Caird, Michelle S; Marini, Joan C; Kozloff, Kenneth M
2015-02-01
Osteogenesis imperfecta (OI) is a heritable collagen-related bone dysplasia, characterized by brittle bones with increased fracture risk that presents most severely in children. Anti-resorptive bisphosphonates are frequently used to treat pediatric OI and controlled clinical trials have shown that bisphosphonate therapy improves vertebral outcomes but has little benefit on long bone fracture rate. New treatments which increase bone mass throughout the pediatric OI skeleton would be beneficial. Sclerostin antibody (Scl-Ab) is a potential candidate anabolic therapy for pediatric OI and functions by stimulating osteoblastic bone formation via the canonical Wnt signaling pathway. To explore the effect of Scl-Ab on the rapidly growing OI skeleton, we treated rapidly growing 3week old Brtl/+ mice, harboring a typical heterozygous OI-causing Gly→Cys substitution on col1a1, for 5weeks with Scl-Ab. Scl-Ab had anabolic effects in Brtl/+ and led to new cortical bone formation and increased cortical bone mass. This anabolic action resulted in improved mechanical strength to WT Veh levels without altering the underlying brittle nature of the material. While Scl-Ab was anabolic in trabecular bone of the distal femur in both genotypes, the effect was less strong in these rapidly growing Brtl/+ mice compared to WT. In conclusion, Scl-Ab was able to stimulate bone formation in a rapidly growing Brtl/+ murine model of OI, and represents a potential new therapy to improve bone mass and reduce fracture risk in pediatric OI. Copyright © 2014 Elsevier Inc. All rights reserved.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Zhu Lingling; Zaidi, Samir; Peng Yuanzhen
Strontium ranelate, a new agent for the treatment of osteoporosis, has been shown stimulate bone formation in various experimental models. This study examines the effect of strontium ranelate on gene expression in osteoblasts, as well as the formation of mineralized (von Kossa-positive) colony-forming unit-osteoblasts (CFU-obs). Bone marrow-derived stromal cells cultured for 21 days under differentiating conditions, when exposed to strontium ranelate, displayed a significant time- and concentration-dependent increase in the expression of the master gene, Runx2, as well as bone sialoprotein (BSP), but interestingly without effects on osteocalcin. This was associated with a significant increase in the formation of CFU-obsmore » at day 21 of culture. In U-33 pre-osteoblastic cells, strontium ranelate significantly enhanced the expression of Runx2 and osteocalcin, but not BSP. Late, more mature osteoblastic OB-6 cells showed significant elevations in BSP and osteocalcin, but with only minimal effects on Runx2. In conclusion, strontium ranelate stimulates osteoblast differentiation, but the induction of the program of gene expression appears to be cell type-specific. The increased osteoblastic differentiation is the likely basis underlying the therapeutic bone-forming actions of strontium ranelate.« less
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Decco, Oscar A.; Beltrán, Víctor; Zuchuat, Jésica I.; Cura, Andrea C.; Lezcano, María F.; Engelke, Wilfried
2015-01-01
Background: Bone augmentation is a subject of intensive investigation in regenerative bone medicine and constitutes a clinical situation in which autogenous bone grafts or synthetic materials are used to aid new bone formation. Method: Based on a non-critical defect, Co-Cr barrier membranes were placed on six adult Fauve de Bourgogne rabbits, divided into two groups: whole blood and PRP. Three densitometric controls were performed during the experiment. The animals were euthanized at 30, 45, 60, and 110 days. The presence of newly formed bone was observed. Samples for histological studies were taken from the augmentation center. Results: External and internal bone tissue augmentation was observed in almost all cases. Significant differences between PRP- and whole blood–stimulated bone augmentation were not observed. At 60 days, bones with PRP presented higher angiogenesis, which may indicate more proliferation and cellular activity. Conclusion: PRP activates the bone regeneration process under optimized conditions by stimulation of osteoblast proliferation after six weeks, when a significant difference in cellular activity was observed. Membranes could stimulate bone augmentation at the site of placement and in the surrounding areas. PMID:28793476
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Skeletal unloading induces selective resistance to the anabolic actions of growth hormone on bone
NASA Technical Reports Server (NTRS)
Halloran, B. P.; Bikle, D. D.; Harris, J.; Autry, C. P.; Currier, P. A.; Tanner, S.; Patterson-Buckendahl, P.; Morey-Holton, E.
1995-01-01
Loss of skeletal weight bearing or physical unloading of bone in the growing animal inhibits bone formation and induces a bone mineral deficit. To determine whether the inhibition of bone formation induced by skeletal unloading in the growing animal is a consequence of diminished sensitivity to growth hormone (GH) we studied the effects of skeletal unloading in young hypophysectomized rats treated with GH (0, 50, 500 micrograms/100 g body weight/day). Skeletal unloading reduced serum osteocalcin, impaired uptake of 3H-proline into bone, decreased proximal tibial mass, and diminished periosteal bone formation at the tibiofibular junction. When compared with animals receiving excipient alone, GH administration increased bone mass in all animals. The responses in serum osteocalcin, uptake of 3H-proline and 45Ca into the proximal tibia, and proximal tibial mass in non-weight bearing animals were equal to those in weight bearing animals. The responses in trabecular bone volume in the proximal tibia and bone formation at the tibiofibular junction to GH, however, were reduced significantly by skeletal unloading. Bone unloading prevented completely the increase in metaphyseal trabecular bone normally induced by GH and severely dampened the stimulatory effect (158% vs. 313%, p < 0.002) of GH on periosteal bone formation. These results suggest that while GH can stimulate the overall accumulation of bone mineral in both weight bearing and non-weight bearing animals, skeletal unloading selectively impairs the response of trabecular bone and periosteal bone formation to the anabolic actions of GH.
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Wang, Zhifa; Weng, Yanming; Lu, Shengjun; Zong, Chunlin; Qiu, Jianyong; Liu, Yanpu; Liu, Bin
2015-08-01
To analyze the effects of platelet-rich fibrin (PRF) on mesenchymal stem cells (MSCs) in vitro and investigate in vivo bone formation by MSC sheets with PRF. Cell proliferation and expression of osteogenesis-related genes within MSC sheets were assessed upon exposure to PRF from the same donors. We then injected MSC sheet fragments with or without PRF subcutaneously in nude mice and assessed bone formation by micro-computed tomography and histological analyses. PRF significantly stimulated MSC proliferation and osteogenesis in vitro. MSC sheets injected with or without PRF formed new bone, but those with PRF produced significantly more and denser bone. MSC sheets can be used to generate tissue engineered bone upon injection, and PRF increases the osteogenic capacity of MSC sheets in vitro and in vivo. © 2014 Wiley Periodicals, Inc.
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Decursin from Angelica gigas suppresses RANKL-induced osteoclast formation and bone loss.
Wang, Xin; Zheng, Ting; Kang, Ju-Hee; Li, Hua; Cho, Hyewon; Jeon, Raok; Ryu, Jae-Ha; Yim, Mijung
2016-03-05
Osteoclasts are the only cells capable of breaking down bone matrix, and excessive activation of osteoclasts is responsible for bone-destructive diseases. In this study, we investigated the effects of decursin from extract of Angelica gigas root on receptor activator of nuclear factor kappa B ligand (RANKL)-induced osteoclast formation using mouse bone marrow-derived macrophages (BMMs). Decursin inhibited RANKL-induced osteoclast formation without cytotoxicity. In particular, decursin maintains the characteristics of macrophages by blocking osteoclast differentiation by RANKL. Furthermore, the RANKL-stimulated bone resorption was diminished by decursin. Mechanistically, decursin blocked the RANKL-triggered ERK mitogen-activated protein kinases (MAPK) phosphorylation, which results in suppression of c-Fos and the nuclear factor of activated T cells (NFATc1) expression. In accordance with the in vitro study, decursin reduced lipopolysaccharide (LPS)- or ovariectomy (OVX)-induced bone loss in vivo. Therefore, decursin exerted an inhibitory effect on osteoclast formation and bone loss in vitro and in vivo. Decursin could be useful for the treatment of bone diseases associated with excessive bone resorption. Copyright © 2016 Elsevier B.V. All rights reserved.
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Salubrinal improves mechanical properties of the femur in osteogenesis imperfecta mice.
Takigawa, Shinya; Frondorf, Brian; Liu, Shengzhi; Liu, Yang; Li, Baiyan; Sudo, Akihiro; Wallace, Joseph M; Yokota, Hiroki; Hamamura, Kazunori
2016-10-01
Salubrinal is an agent that reduces the stress to the endoplasmic reticulum by inhibiting de-phosphorylation of eukaryotic translation initiation factor 2 alpha (eIF2α). We and others have previously shown that the elevated phosphorylation of eIF2α stimulates bone formation and attenuates bone resorption. In this study, we applied salubrinal to a mouse model of osteogenesis imperfecta (Oim), and examined whether it would improve Oim's mechanical property. We conducted in vitro experiments using RAW264.7 pre-osteoclasts and bone marrow derived cells (BMDCs), and performed in vivo administration of salubrinal to Oim (+/-) mice. The animal study included two control groups (wildtype and Oim placebo). The result revealed that salubrinal decreased expression of nuclear factor of activated T cells cytoplasmic 1 (NFATc1) and suppressed osteoclast maturation, and it stimulated mineralization of mesenchymal stem cells from BMDCs. Furthermore, daily injection of salubrinal at 2 mg/kg for 2 months made stiffness (N/mm) and elastic module (GPa) of the femur undistinguishable to those of the wildtype control. Collectively, this study supported salubrinal's beneficial role to Oim's femora. Unlike bisphosphonates, salubrinal stimulates bone formation. For juvenile OI patients who may favor strengthening bone without inactivating bone remodeling, salubrinal may present a novel therapeutic option. Copyright © 2016 The Authors. Production and hosting by Elsevier B.V. All rights reserved.
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Accardi, Fabrizio; Toscani, Denise; Dalla Palma, Benedetta; Aversa, Franco; Giuliani, Nicola
2015-01-01
Multiple myeloma (MM) is characterized by a high capacity to induce alterations in the bone remodeling process. The increase in osteoclastogenesis and the suppression of osteoblast formation are both involved in the pathophysiology of the bone lesions in MM. The proteasome inhibitor (PI) bortezomib is the first drug designed and approved for the treatment of MM patients by targeting the proteasome. However, recently novel PIs have been developed to overcome bortezomib resistance. Interestingly, several preclinical data indicate that the proteasome complex is involved in both osteoclast and osteoblast formation. It is also evident that bortezomib either inhibits osteoclast differentiation induced by the receptor activator of nuclear factor kappa B (NF-κB) ligand (RANKL) or stimulates the osteoblast differentiation. Similarly, the new PIs including carfilzomib and ixazomib can inhibit bone resorption and stimulate the osteoblast differentiation. In a clinical setting, PIs restore the abnormal bone remodeling by normalizing the levels of bone turnover markers. In addition, a bone anabolic effect was described in responding MM patients treated with PIs, as demonstrated by the increase in the osteoblast number. This review summarizes the preclinical and clinical evidence on the effects of bortezomib and other new PIs on myeloma bone disease. PMID:26579531
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Ma, Yanfei L; Hamang, Matthew; Lucchesi, Jonathan; Bivi, Nicoletta; Zeng, Qianqiang; Adrian, Mary D; Raines, Sarah E; Li, Jiliang; Kuhstoss, Stuart A; Obungu, Victor; Bryant, Henry U; Krishnan, Venkatesh
2017-04-01
Sclerostin antibodies increase bone mass by stimulating bone formation. However, human and animal studies show that bone formation increases transiently and returns to pre-treatment level despite ongoing antibody treatment. To understand its mechanism of action, we studied the time course of bone formation, correlating the rate and extent of accrual of bone mass and strength after sclerostin antibody treatment. Ovariectomized (OVX) rats were treated with a sclerostin-antibody (Scle-ab) at 20mg/kg sc once weekly and sacrificed at baseline and 2, 3, 4, 6, and 8weeks post-treatment. In Scle-ab treated rats, serum PINP and OCN rapidly increased at week 1, peaked around week 3, and returned to OVX control levels by week 6. Transcript analyses from the distal femur revealed an early increase in bone formation followed by a sustained decrease in bone resorption genes. Lumbar vertebral (LV) osteoblast surface increased 88% by week 2, and bone formation rate (BFR/BS) increased 138% by week 4. Both parameters were below OVX control by week 8. Bone formation was primarily a result of modeling based formation. Endocortical and periosteal BFR/BS peaked around week 4 at 313% and 585% of OVX control, respectively. BFR/BS then declined but remained higher than OVX control on both surfaces through week 8. Histomorphometric analyses showed LV-BV/TV did not further increase after week 4, while BMD continued to increase at LV, mid femur (MF), and femoral neck (FN) through week 8. Biomechanical tests showed a similar improvement in bone strength through 8weeks in MF and FN, but bone strength plateaued between weeks 6 and 8 for LV. Our data suggest that bone formation with Scle-ab treatment is rapid and modeling formation dominated in OVX rats. Although transient, the bone formation response persists longer in cortical than trabecular bone. Copyright © 2016 Elsevier Inc. All rights reserved.
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Yamaguchi, Masayoshi; Moore, Terry W; Sun, Aiming; Snyder, James P; Shoji, Mamoru
2012-08-01
Bone homeostasis is maintained through a balance between osteoblastic bone formation and osteoclastic bone resorption. Bone loss is induced due to decreased osteoblastic bone formation and increased osteoclastic bone resorption with various pathologic states. Osteoporosis with its accompanying decrease in bone mass is widely recognized as a major public health problem. Pharmacologic and functional food factors may play a role in the prevention of bone loss with aging. This study was undertaken to determine the effect of curcumin analogues (curcumin, EF31, ECMN909, and UBS109), which were newly synthesized, on osteoblastogenesis and osteoclastogenesis in vitro. Among these compounds, UBS109 had a unique stimulatory effect on osteoblastic differentiation and mineralization. UBS109 stimulated both basal and bone morphogenic protein-2 (BMP2)-increased Smad-luciferase activity, the Smad signaling of which is related to osteoblastogenesis. Such an effect was not seen with other compounds. Moreover, UBS109 potently suppressed tumor necrosis factor-α (TNF-α)-increased osteoblastic nuclear factor kappa B (NF-κB)-luciferase activity. In addition, EF31, ECMN909, and UBS109 had a suppressive effect on osteoclastogenesis as compared with that of curcumin. ECMN909 and UBS109 potently inhibited the receptor activator of NF-κB (RANK) ligand (RANKL)-increased preosteoclastic NF-κB-luciferase activity, in which NF-κB signaling plays a pivotal role in osteoclastogenesis. In the present study, curcumin analogue UBS109 was found to have a stimulating effect on osteoblastogenesis and a suppressive effect on osteoclastogenesis in vitro, suggesting an anabolic effect of the compound on bone mass.
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Sugamori, Yasutaka; Mise‐Omata, Setsuko; Maeda, Chizuko; Aoki, Shigeki; Tabata, Yasuhiko; Murali, Ramachandran; Yasuda, Hisataka; Udagawa, Nobuyuki; Suzuki, Hiroshi; Honma, Masashi
2016-01-01
Both W9 and OP3‐4 were known to bind the receptor activator of NF‐κB ligand (RANKL), inhibiting osteoclastogenesis. Recently, both peptides were shown to stimulate osteoblast differentiation; however, the mechanism underlying the activity of these peptides remains to be clarified. A primary osteoblast culture showed that rapamycin, an mTORC1 inhibitor, which was recently demonstrated to be an important serine/threonine kinase for bone formation, inhibited the peptide‐induced alkaline phosphatase activity. Furthermore, both peptides promoted the phosphorylation of Akt and S6K1, an upstream molecule of mTORC1 and the effector molecule of mTORC1, respectively. In the in vivo calvarial defect model, W9 and OP3‐4 accelerated BMP‐2‐induced bone formation to a similar extent, which was confirmed by histomorphometric analyses using fluorescence images of undecalcified sections. Our data suggest that these RANKL‐binding peptides could stimulate the mTORC1 activity, which might play a role in the acceleration of BMP‐2‐induced bone regeneration by the RANKL‐binding peptides. PMID:27345003
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Weivoda, Megan M; Ruan, Ming; Pederson, Larry; Hachfeld, Christine; Davey, Rachel A; Zajac, Jeffrey D; Westendorf, Jennifer J; Khosla, Sundeep; Oursler, Merry Jo
2016-01-01
Osteoblast-mediated bone formation is coupled to osteoclast-mediated bone resorption. These processes become uncoupled with age, leading to increased risk for debilitating fractures. Therefore, understanding how osteoblasts are recruited to sites of resorption is vital to treating age-related bone loss. Osteoclasts release and activate TGF-β from the bone matrix. Here we show that osteoclastspecific inhibition of TGF-β receptor signaling in mice results in osteopenia due to reduced osteoblast numbers with no significant impact on osteoclast numbers or activity. TGF-β induced osteoclast expression of Wnt1, a protein crucial to normal bone formation, and this response was blocked by impaired TGF-β receptor signaling. Osteoclasts in aged murine bones had lower TGF-β signaling and Wnt1 expression in vivo. Ex vivo stimulation of osteoclasts derived from young or old mouse bone marrow macrophages showed no difference in TGF-β–induced Wnt1 expression. However, young osteoclasts expressed reduced Wnt1 when cultured on aged mouse bone chips compared to young mouse bone chips, consistent with decreased skeletal TGF-β availability with age. Therefore, osteoclast responses to TGF-β are essential for coupling bone resorption to bone formation, and modulating this pathway may provide opportunities to treat age-related bone loss. PMID:26108893
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Chantarawaratit, P; Sangvanich, P; Banlunara, W; Soontornvipart, K; Thunyakitpisal, P
2014-04-01
Periodontal disease is a common infectious disease, found worldwide, causing the destruction of the periodontium. The periodontium is a complex structure composed of both soft and hard tissues, thus an agent applied to regenerate the periodontium must be able to stimulate periodontal ligament, cementum and alveolar bone regeneration. Recent studies demonstrated that acemannan, a polysaccharide extracted from Aloe vera gel, stimulated both soft and hard tissue healing. This study investigated effect of acemannan as a bioactive molecule and scaffold for periodontal tissue regeneration. Primary human periodontal ligament cells were treated with acemannan in vitro. New DNA synthesis, expression of growth/differentiation factor 5 and runt-related transcription factor 2, expression of vascular endothelial growth factor, bone morphogenetic protein-2 and type I collagen, alkaline phosphatase activity, and mineralized nodule formation were determined using [(3)H]-thymidine incorporation, reverse transcription-polymerase chain reaction, enzyme-linked immunoabsorbent assay, biochemical assay and alizarin red staining, respectively. In our in vivo study, premolar class II furcation defects were made in four mongrel dogs. Acemannan sponges were applied into the defects. Untreated defects were used as a negative control group. The amount of new bone, cementum and periodontal ligament formation were evaluated 30 and 60 d after the operation. Acemannan significantly increased periodontal ligament cell proliferation, upregulation of growth/differentiation factor 5, runt-related transcription factor 2, vascular endothelial growth factor, bone morphogenetic protein 2, type I collagen and alkaline phosphatase activity, and mineral deposition as compared with the untreated control group in vitro. Moreover, acemannan significantly accelerated new alveolar bone, cementum and periodontal ligament formation in class II furcation defects. Our data suggest that acemannan could be a candidate biomolecule for periodontal tissue regeneration. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
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Zhou, Hua; Recker, Robert R.; Brown, Jacques P.; Recknor, Christopher P.; Lewiecki, E. Michael; Miller, Paul D.; Rao, Sudhaker D.; Kendler, David L.; Lindsay, Robert; Krege, John H.; Alam, Jahangir; Taylor, Kathleen A.; Janos, Boris; Ruff, Valerie A.
2016-01-01
Context: Denosumab-induced PTH elevation may stimulate early bone formation. Objective: Our objective was to evaluate whether denosumab-induced changes of intact PTH (iPTH) result in early anabolic effects according to histomorphometry and bone turnover markers (BTMs) compared with teriparatide, an established anabolic agent. Design: This open-label, randomized study used quadruple labeling to label bone before/after treatment, with a transiliac bone biopsy at 3 months. Setting: This study took both in both US and Canadian sites. Participants: Sixty-nine postmenopausal women with osteoporosis were included. Interventions: Teriparatide (20 μg/day) for 6 months and denosumab (60 mg once) were used in this study. Main Outcome Measure: Between-treatment comparison of change from baseline to month 3 in cancellous mineralizing surface/bone surface, histomorphometric indices in four bone envelopes, and BTM and iPTH at baseline, 1, 3, and 6 months was undertaken. Results: After denosumab, iPTH peaked at month 1 (P < .001), then declined, remaining above baseline through month 6 (P ≤ .01); after teriparatide, iPTH declined at all time points (P < .001). From baseline to month 3, cancellous mineralizing surface/bone surface increased with teriparatide and decreased with denosumab and at month 3, was higher with teriparatide. Similar results were observed in other bone envelopes. BTMs increased from baseline in teriparatide-treated subjects (procollagen type 1 N-terminal propeptide at month 1 and carboxyterminal cross-linking telopeptide of type 1 collagen at month 3); procollagen type 1 N-terminal propeptide and carboxyterminal cross-linking telopeptide of type 1 collagen decreased from baseline at all time points in denosumab-treated subjects. Conclusions: Denosumab treatment increased iPTH but inhibited bone formation indices. In contrast, teriparatide treatment decreased iPTH but stimulated bone formation indices. These findings are not consistent with the hypothesis of early indirect anabolic effect with denosumab. PMID:26859106
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Mohanty, Sindhu T.; Seckinger, Anja; Terry, Rachael L.; Pettitt, Jessica A.; Simic, Marija K.; Le, Lawrence M. T.; Kramer, Ina; Falank, Carolyne; Fairfield, Heather; Ghobrial, Irene M.; Baldock, Paul A.; Little, David G.; Kneissel, Michaela; Vanderkerken, Karin; Bassett, J. H. Duncan; Williams, Graham R.; Oyajobi, Babatunde O.; Hose, Dirk
2017-01-01
Multiple myeloma (MM) is a plasma cell cancer that develops in the skeleton causing profound bone destruction and fractures. The bone disease is mediated by increased osteoclastic bone resorption and suppressed bone formation. Bisphosphonates used for treatment inhibit bone resorption and prevent bone loss but fail to influence bone formation and do not replace lost bone, so patients continue to fracture. Stimulating bone formation to increase bone mass and fracture resistance is a priority; however, targeting tumor-derived modulators of bone formation has had limited success. Sclerostin is an osteocyte-specific Wnt antagonist that inhibits bone formation. We hypothesized that inhibiting sclerostin would prevent development of bone disease and increase resistance to fracture in MM. Sclerostin was expressed in osteocytes from bones from naive and myeloma-bearing mice. In contrast, sclerostin was not expressed by plasma cells from 630 patients with myeloma or 54 myeloma cell lines. Mice injected with 5TGM1-eGFP, 5T2MM, or MM1.S myeloma cells demonstrated significant bone loss, which was associated with a decrease in fracture resistance in the vertebrae. Treatment with anti-sclerostin antibody increased osteoblast numbers and bone formation rate but did not inhibit bone resorption or reduce tumor burden. Treatment with anti-sclerostin antibody prevented myeloma-induced bone loss, reduced osteolytic bone lesions, and increased fracture resistance. Treatment with anti-sclerostin antibody and zoledronic acid combined increased bone mass and fracture resistance when compared with treatment with zoledronic acid alone. This study defines a therapeutic strategy superior to the current standard of care that will reduce fractures for patients with MM. PMID:28515094
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Bone regeneration: molecular and cellular interactions with calcium phosphate ceramics
Barrère, Florence; van Blitterswijk, Clemens A; de Groot, Klaas
2006-01-01
Calcium phosphate bioceramics are widely used in orthopedic and dental applications and porous scaffolds made of them are serious candidates in the field of bone tissue engineering. They have superior properties for the stimulation of bone formation and bone bonding, both related to the specific interactions of their surface with the extracellular fluids and cells, ie, ionic exchanges, superficial molecular rearrangement and cellular activity. PMID:17717972
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Levi, Benjamin; Nelson, Emily R.; Li, Shuli; James, Aaron W.; Hyun, Jeong S.; Montoro, Daniel T.; Lee, Min; Glotzbach, Jason P.; Commons, George W.; Longaker, Michael T.
2015-01-01
Human adipose-derived stromal cells (hASCs) have a proven capacity to aid in osseous repair of calvarial defects. However, the bone defect microenvironment necessary for osseous healing is not fully understood. In this study, we postulated that the cell-cell interaction between engrafted ASCs and host dura mater (DM) cells is critical for the healing of calvarial defects. hASCs were engrafted into critical sized calvarial mouse defects. The DM-hASC interaction was manipulated surgically by DM removal or by insertion of a semipermeable or nonpermeable membrane between DM and hASCs. Radiographic, histologic, and gene expression analyses were performed. Next, the hASC-DM interaction is assessed by conditioned media (CM) and coculture assays. Finally, bone morphogenetic protein (BMP) signaling from DM was investigated in vivo using novel BMP-2 and anti-BMP-2/4 slow releasing scaffolds. With intact DM, osseous healing occurs both from host DM and engrafted hASCs. Interference with the DM-hASC interaction dramatically reduced calvarial healing with abrogated BMP-2–Smad-1/5 signaling. Using CM and coculture assays, mouse DM cells stimulated hASC osteogenesis via BMP signaling. Through in vivo manipulation of the BMP-2 pathway, we found that BMP-2 plays an important role in DM stimulation of hASC osteogenesis in the context of calvarial bone healing. BMP-2 supplementation to a defect with disrupted DM allowed for bone formation in a nonhealing defect. DM is an osteogenic cell type that both participates in and stimulates osseous healing in a hASC-engrafted calvarial defect. Furthermore, DM-derived BMP-2 paracrine stimulation appears to play a key role for hASC mediated repair. PMID:21656608
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NASA Technical Reports Server (NTRS)
Ma, Y. F.; Ke, H. Z.; Jee, W. S. S.
1994-01-01
The objects of this study were to determine the responses of a cancellous bone site with a closed growth plate, (the distal tibial metaphysis (DTM), to ovariectomy (OVX) and OVX plus a prostaglandin E(2) treatment, and compare the site's response to previous findings reported for another site, the proximal tibial metaphysis (PTM). Thirty five 3-month old female Sprague-Dawley rats were divided into five groups; basal, sham OVX, and OVX+0, +1, or +6 mg PGE(2)/kg/d injected subcutaneously for 3 months and given double fluorescent labels before sacrifice. Cancellous bone histomorphometric analyses were performed on 20 micrometer thick undecalcified DTM sections. Similar to the PTM, the DTM showed age-related decreases in bone formation and increases in bone resorption, but it differed in that at 3 months POST OVX there was neither bone loss nor changes in formation endpoints. Giving 1 mg PGE(2)/kg/d to OVX rats prevented most age-related changes and maintained the bone formation histomorphometry near basal levels. Treating OVX rats with 6 mg PGE(2)/kd/d prevented age-related bone changes, added extra bone, and improved microanatomical structure by stimulating bone formation, without altering bone resportion. Futhermore, After PGE(2) admimnistration, the DTM, a cancellous bone site with a closed growth plate, increased bone formation more than did the cancellous bone in the PTM.
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NASA Technical Reports Server (NTRS)
Ma, Y. F.; Ke, H. Z.; Jee, W. S. S.
1994-01-01
The objects of this study were to determine the responses of a cancellous bone site with a closed growth plate (the distal tibial metaphysis, DTM) to ovariectomy (OVX) and OVX plus a prostaglandin E2 (PGE2) treatment, and compare the site's response to previous findings reported for another site (the proximal tibial metaphysis, PTM). Thirty-five 3-month old female Sprague-Dawley rats were divided into five groups: basal, sham-OVX, and OVX+0, +1, or +6 mg PGE2/kg/d injected subcutaneously for 3 months and given double fluorescent labels before sacrifice. Cancellous bone histomorphometric analyses were performed on 20-micron-thick undecalcified DTM sections. Similar to the PTM, the DTM showed age-related decreases in bone formation and increases in bone resorption, but it differed in that at 3 months post-OVX; there was neither bone loss nor changes in formation endpoints. Giving 1 mg PGE2/kg/d to OVX rats prevented most age-related changes and maintained the bone formation histomorphometry near basal levels. Treating OVX rats with 6 mg PGE2/kg/d prevented age-related bone changes, added extra bone, and improved microanatomical structure by stimulating bone formation without altering bone resorption. Furthermore, after PGE2 administration, the DTM, a cancellous bone site with a closed growth plate, inereased bone formation more than did the cancellous bone in the PTM.
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Increased bone density in mice lacking the proton receptor, OGR1
Krieger, Nancy S.; Yao, Zhenqiang; Kyker-Snowman, Kelly; Kim, Min Ho; Boyce, Brendan F.; Bushinsky, David A.
2016-01-01
Chronic metabolic acidosis stimulates cell-mediated calcium efflux from bone through osteoblastic prostaglandin E2-induced stimulation of RANKL leading to increased osteoclastic bone resorption. Osteoblasts express the proton-sensing G-protein coupled receptor, OGR1, which activates IP3-mediated intracellular calcium. Proton-induced osteoblastic intracellular calcium signaling requires OGR1, suggesting OGR1 is the sensor activated during acidosis to cause bone resorption. Growing mice produce large amounts of metabolic acids which must be buffered, primarily by bone, prior to excretion by the kidney. Here we tested whether lack of OGR1 inhibits proton-induced bone resorption by measuring bone mineral density by μCT and histomorphometry in 8 week old male OGR1−/− and C57/Bl6 wild type mice. OGR1−/− mice have normal skeletal development with no atypical gross phenotype. Trabecular and cortical bone volume was increased in tibiae and vertebrae from OGR1−/−. There were increased osteoblast numbers on the cortical and trabecular surfaces of tibiae from OGR1−/− mice, increased endocortical and trabecular bone formation rates, and osteoblastic gene expression. Osteoclast numbers and surface were increased in tibiae of OGR1−/− mice. Thus, in rapidly growing mice, lack of OGR1 leads to increased bone mass with increased bone turnover and a greater increase in bone formation than resorption. This supports the important role of the proton receptor, OGR1, in the response of bone to protons. PMID:26880453
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Nell-1-Induced Bone Regeneration in Calvarial Defects
Aghaloo, Tara; Cowan, Catherine M.; Chou, Yu-Fen; Zhang, Xinli; Lee, Haofu; Miao, Steve; Hong, Nichole; Kuroda, Shun’ichi; Wu, Benjamin; Ting, Kang; Soo, Chia
2006-01-01
Many craniofacial birth defects contain skeletal components requiring bone grafting. We previously identified the novel secreted osteogenic molecule NELL-1, first noted to be overexpressed during premature bone formation in calvarial sutures of craniosynostosis patients. Nell-1 overexpression significantly increases differentiation and mineralization selectively in osteoblasts, while newborn Nell-1 transgenic mice significantly increase premature bone formation in calvarial sutures. In the current study, cultured calvarial explants isolated from Nell-1 transgenic newborn mice (with mild sagittal synostosis) demonstrated continuous bone growth and overlapping sagittal sutures. Further investigation into gene expression cascades revealed that fibroblast growth factor-2 and transforming growth factor-β1 stimulated Nell-1 expression, whereas bone morphogenetic protein (BMP)-2 had no direct effect. Additionally, Nell-1-induced osteogenesis in MC3T3-E1 osteoblasts through reduction in the expression of early up-regulated osteogenic regulators (OSX and ALP) but induction of later markers (OPN and OCN). Grafting Nell-1 protein-coated PLGA scaffolds into rat calvarial defects revealed the osteogenic potential of Nell-1 to induce bone regeneration equivalent to BMP-2, whereas immunohistochemistry indicated that Nell-1 reduced osterix-producing cells and increased bone sialoprotein, osteocalcin, and BMP-7 expression. Insights into Nell-1-regulated osteogenesis coupled with its ability to stimulate bone regeneration revealed a potential therapeutic role and an alternative to the currently accepted techniques for bone regeneration. PMID:16936265
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Lu, Yan; Lee, Jae Sung; Nemke, Brett; Graf, Ben K.; Royalty, Kevin; Illgen, Richard; Vanderby, Ray; Markel, Mark D.; Murphy, William L.
2012-01-01
Despite the potential for growth factor delivery strategies to promote orthopedic implant healing, there is a need for growth factor delivery methods that are controllable and amenable to clinical translation. We have developed a modular bone growth factor, herein termed “modular bone morphogenetic peptide (mBMP)”, which was designed to efficiently bind to the surface of orthopedic implants and also stimulate new bone formation. The purpose of this study was to coat a hydroxyapatite-titanium implant with mBMP and evaluate bone healing across a bone-implant gap in the sheep femoral condyle. The mBMP molecules efficiently bound to a hydroxyapatite-titanium implant and 64% of the initially bound mBMP molecules were released in a sustained manner over 28 days. The results demonstrated that the mBMP-coated implant group had significantly more mineralized bone filling in the implant-bone gap than the control group in C-arm computed tomography (DynaCT) scanning (25% more), histological (35% more) and microradiographic images (50% more). Push-out stiffness of the mBMP group was nearly 40% greater than that of control group whereas peak force did not show a significant difference. The results of this study demonstrated that mBMP coated on a hydroxyapatite-titanium implant stimulates new bone formation and may be useful to improve implant fixation in total joint arthroplasty applications. PMID:23185610
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Cyclic hydrostatic pressure stimulates enhanced bone development in the foetal chick femur in vitro.
Henstock, J R; Rotherham, M; Rose, J B; El Haj, A J
2013-04-01
Mechanical loading of bone and cartilage in vivo results in the generation of cyclic hydrostatic forces as bone compression is transduced to fluid pressure in the canalicular network and the joint synovium. It has therefore been suggested that hydrostatic pressure is an important stimulus by which osteochondral cells and their progenitors sense and respond to mechanical loading in vivo. In this study, hydrostatic pressure regimes of 0-279kPa at 0.005-2Hz were applied to organotypically cultured ex vivo chick foetal femurs (e11) for 1hour per day in a custom designed bioreactor for 14days and bone formation assessed by X-ray microtomography and qualified by histology. We found that the mineralised portion of the developing femur cultured under any cyclic hydrostatic pressure regime was significantly larger and/or denser than unstimulated controls but that constant (non-cycling) hydrostatic pressure had no effect on bone growth. Further experiments showed that the increase in bone formation was directly proportional to stimulation frequency (R(2)=0.917), but independent of the magnitude of the pressure applied, whilst even very low frequencies of stimulation (0.005Hz) had significant effects on bone growth. Expression of Type-II collagen in both epiphyses and diaphysis was significantly upregulated (1.48-fold and 1.95-fold respectively), together with osteogenic genes (osteonectin and osteopontin) and the osteocyte maturation marker CD44. This work demonstrates that cyclic hydrostatic pressure promotes bone growth and mineralisation in a developmental model and supports the hypothesis that hydrostatic forces play an important role in regulating bone growth and remodelling in vivo. Copyright © 2013 Elsevier Inc. All rights reserved.
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IL-12p40 impairs mesenchymal stem cell-mediated bone regeneration via CD4+ T cells
Xu, Jiajia; Wang, Yiyun; Li, Jing; Zhang, Xudong; Geng, Yiyun; Huang, Yan; Dai, Kerong; Zhang, Xiaoling
2016-01-01
Severe or prolonged inflammatory response caused by infection or biomaterials leads to delayed healing or bone repair failure. This study investigated the important roles of the proinflammatory cytokines of the interleukin-12 (IL-12) family, namely, IL-12 and IL-23, in the inflammation-mediated inhibition of bone formation in vivo. IL-12p40−/− mice lacking IL-12 and IL-23 exhibited enhanced bone formation. IL-12 and IL-23 indirectly inhibited bone marrow mesenchymal stem cell (BMMSC) differentiation by stimulating CD4+ T cells to increase interferon γ (IFN-γ) and IL-17 levels. Mechanistically, IL-17 synergistically enhanced IFN-γ-induced BMMSC apoptosis. Moreover, INF-γ and IL-17 exerted proapoptotic effects by upregulating the expression levels of Fas and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), as well as by activating the caspase cascade in BMMSCs. IL-12p40 depletion in mice could promote ectopic bone formation. Thus, IL-12p40 is an attractive therapeutic target to overcome the inflammation-mediated inhibition of bone formation in vivo. PMID:27472064
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Targeting sphingosine-1-phosphate lyase as an anabolic therapy for bone loss.
Weske, Sarah; Vaidya, Mithila; Reese, Alina; von Wnuck Lipinski, Karin; Keul, Petra; Bayer, Julia K; Fischer, Jens W; Flögel, Ulrich; Nelsen, Jens; Epple, Matthias; Scatena, Marta; Schwedhelm, Edzard; Dörr, Marcus; Völzke, Henry; Moritz, Eileen; Hannemann, Anke; Rauch, Bernhard H; Gräler, Markus H; Heusch, Gerd; Levkau, Bodo
2018-05-01
Sphingosine-1-phosphate (S1P) signaling influences bone metabolism, but its therapeutic potential in bone disorders has remained unexplored. We show that raising S1P levels in adult mice through conditionally deleting or pharmacologically inhibiting S1P lyase, the sole enzyme responsible for irreversibly degrading S1P, markedly increased bone formation, mass and strength and substantially decreased white adipose tissue. S1P signaling through S1P 2 potently stimulated osteoblastogenesis at the expense of adipogenesis by inversely regulating osterix and PPAR-γ, and it simultaneously inhibited osteoclastogenesis by inducing osteoprotegerin through newly discovered p38-GSK3β-β-catenin and WNT5A-LRP5 pathways. Accordingly, S1P 2 -deficient mice were osteopenic and obese. In ovariectomy-induced osteopenia, S1P lyase inhibition was as effective as intermittent parathyroid hormone (iPTH) treatment in increasing bone mass and was superior to iPTH in enhancing bone strength. Furthermore, lyase inhibition in mice successfully corrected severe genetic osteoporosis caused by osteoprotegerin deficiency. Human data from 4,091 participants of the SHIP-Trend population-based study revealed a positive association between serum levels of S1P and bone formation markers, but not resorption markers. Furthermore, serum S1P levels were positively associated with serum calcium , negatively with PTH , and curvilinearly with body mass index. Bone stiffness, as determined through quantitative ultrasound, was inversely related to levels of both S1P and the bone formation marker PINP, suggesting that S1P stimulates osteoanabolic activity to counteract decreasing bone quality. S1P-based drugs should be considered as a promising therapeutic avenue for the treatment of osteoporotic diseases.
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S-Ketoprofen Inhibits Tenotomy-Induced Bone Loss and Dynamics in Weanling Rats
NASA Technical Reports Server (NTRS)
Zeng, Q. Q.; Jee, W. S. S.; Ke, H. Z.; Wechter, W. J.
1993-01-01
The objects of this study were to determine whether S-ketoprofen, a non-steroidal anti-inflammatory drug (NSAID), can prevent immobilization (tenotomy)-induced bone loss in weanling rats. Forty five 4 week-old Sprague-Dawley female rats were either sham-operated or subjected to knee tenotomy and treated simultaneously with 0, 0.02, 0.1, 0.5 or 2.5 mg of S-ketoprofen/kg per day for 21 days. We then studied double-fluorescent labeled proximal tibial longitudinal sections and tibial shaft cross sections using static and dynamic histomorphometry. Less cancellous bone mass in proximal tibial metaphyses was found in tenotomized controls than in basal (36%) and sham-operated (54%) controls. This was due to the inhibition of age-related bone gain and induced bone loss due to increased bone resorption and decreased bone formation. S-ketoprofen prevented both the inhibition of age-related bone gain and the stimulation of bone loss at the 2.5 mg/kg per day dose level, while it only prevented bone loss at the 0.5 mg/kg dose levels. In cancellous bone, dynamic histomorphometry showed that S-ketoprofen prevented the tenotomy induced decrease in bone formation and increase in bone resorption. In the tibial shaft, tenotomy inhibited the enlargement of total tissue area by depressing periosteal bone formation, and thus inhibited age-related cortical bone gain. S-ketoprofen treatment did not prevent this change at all dose levels, but reduced marrow cavity area to increase cortical bone area at the 0.1, 0.5 and 2.5 mg/kg per dose levels compared to tenotomy controls. However, the cortical bone area in the 0.1 and 0.5 mg dose-treated treated tenotomy rats was still lower than in the age-related controls. S-ketoprofen also prevented the increase in endocortical eroded perimeter induced by tenotomy. In summary, tenotomy inhibited age-related bone gain and stimulated bone loss in cancellous bone sites, and only inhibited age-related bone gain in cortical bone sites. S-ketoprofen treatment at the highest dose levels prevented the changes in cancellous bone, and reduced marrow area to increase cortical bone in the tibial shafts.
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Bringing new life to damaged bone: the importance of angiogenesis in bone repair and regeneration.
Stegen, Steve; van Gastel, Nick; Carmeliet, Geert
2015-01-01
Bone has the unique capacity to heal without the formation of a fibrous scar, likely because several of the cellular and molecular processes governing bone healing recapitulate the events during skeletal development. A critical component in bone healing is the timely appearance of blood vessels in the fracture callus. Angiogenesis, the formation of new blood vessels from pre-existing ones, is stimulated after fracture by the local production of numerous angiogenic growth factors. The fracture vasculature not only supplies oxygen and nutrients, but also stem cells able to differentiate into osteoblasts and in a later phase also the ions necessary for mineralization. This review provides a concise report of the regulation of angiogenesis by bone cells, its importance during bone healing and its possible therapeutic applications in bone tissue engineering. This article is part of a Special Issue entitled "Stem Cells and Bone". Copyright © 2014 Elsevier Inc. All rights reserved.
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Oxidation-specific epitopes restrain bone formation.
Ambrogini, Elena; Que, Xuchu; Wang, Shuling; Yamaguchi, Fumihiro; Weinstein, Robert S; Tsimikas, Sotirios; Manolagas, Stavros C; Witztum, Joseph L; Jilka, Robert L
2018-06-06
Atherosclerosis and osteoporosis are epidemiologically linked and oxidation specific epitopes (OSEs), such as phosphocholine (PC) of oxidized phospholipids (PC-OxPL) and malondialdehyde (MDA), are pathogenic in both. The proatherogenic effects of OSEs are opposed by innate immune antibodies. Here we show that high-fat diet (HFD)-induced bone loss is attenuated in mice expressing a single chain variable region fragment of the IgM E06 (E06-scFv) that neutralizes PC-OxPL, by increasing osteoblast number and stimulating bone formation. Similarly, HFD-induced bone loss is attenuated in mice expressing IK17-scFv, which neutralizes MDA. Notably, E06-scFv also increases bone mass in mice fed a normal diet. Moreover, the levels of anti-PC IgM decrease in aged mice. We conclude that OSEs, whether produced chronically or increased by HFD, restrain bone formation, and that diminished defense against OSEs may contribute to age-related bone loss. Anti-OSEs, therefore, may represent a novel therapeutic approach against osteoporosis and atherosclerosis simultaneously.
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Kim, Young-Taek; Wikesjö, Ulf M E; Jung, Ui-Won; Lee, Jung-Seok; Kim, Tae-Gyun; Kim, Chong-Kwan
2013-06-01
The objective of this study is to compare a candidate β-tricalcium phosphate (β-TCP) carrier technology with the absorbable collagen sponge (ACS) benchmark to support recombinant human growth/differentiation factor-5 (rhGDF-5)-stimulated periodontal wound healing/regeneration. Routine, bilateral, critical-size (5-mm), 1-wall, intrabony periodontal defects were surgically created in the mandibular premolar region in 10 beagle dogs. Five animals received rhGDF-5/β-TCP and five animals received rhGDF-5/ACS, with a total of 20 μg rhGDF-5 per defect. The animals were euthanized for histologic and histometric analyses at 8 weeks postsurgery. Both rhGDF-5/ACS and rhGDF-5/β-TCP stimulated the formation of functionally oriented periodontal ligament, cellular mixed fiber cementum, and woven/lamellar bone. Bone regeneration (height and area) was significantly greater for the rhGDF-5/β-TCP construct than for the rhGDF-5/ACS (3.26 ± 0.30 mm versus 2.22 ± 0.82 mm, P <0.01; and 10.45 ± 2.26 mm(2) versus 5.62 ± 2.39 mm(2), P <0.01, respectively). Cementum formation ranged from 3.83 ± 0.73 mm to 3.03 ± 1.18 mm without significant differences between groups. Root resorption/ankylosis was not observed. The β-TCP carrier technology significantly enhanced rhGDF-5-stimulated bone formation compared with the ACS benchmark in this discriminating periodontal defect model. The structural integrity of the β-TCP carrier, preventing compression while providing a framework for bone ingrowth, may account for the observed results.
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Harnik, Branko; Miron, Richard J; Buser, Daniel; Gruber, Reinhard
2017-03-01
Angiogenesis is essential for the consolidation of bone allografts. The underlying molecular mechanism, however, remains unclear. Soluble factors released from demineralized freeze-dried bone target mesenchymal cells; however, their effect on endothelial cells has not been investigated so far. The aim of the present study was therefore to examine the effect of conditioned medium from demineralized freeze-dried bone on human umbilical endothelial cells in vitro. Conditioned medium was first prepared from demineralized freeze-dried bone following 24 hours incubation at room temperature to produce demineralized bone conditioned media. Thereafter, conditioned medium was used to stimulate human umbilical vein endothelial cells in vitro by determining the cell response based on viability, proliferation, expression of apoptotic genes, a Boyden chamber to determine cell migration, and the formation of branches. The authors report here that conditioned medium decreased viability and proliferation of endothelial cells. Neither of the apoptotic marker genes was significantly altered when endothelial cells were exposed to conditioned medium. The Boyden chamber revealed that endothelial cells migrate toward conditioned medium. Moreover, conditioned medium moderately stimulated the formation of branches. These findings support the concept that conditioned medium from demineralized freeze-dried bone targets endothelial cells by decreasing their proliferation and enhancing their motility under these in vitro conditions.
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Saito, Mitsuru; Grynpas, Marc D; Burr, David B; Allen, Matthew R; Smith, Susan Y; Doyle, Nancy; Amizuka, Norio; Hasegawa, Tomoka; Kida, Yoshikuni; Marumo, Keishi; Saito, Hitoshi
2015-04-01
Eldecalcitol (ELD), an active form of vitamin D analog approved for the treatment of osteoporosis in Japan, increases lumbar spine bone mineral density (BMD), suppresses bone turnover markers, and reduces fracture risk in patients with osteoporosis. We have previously reported that treatment with ELD for 6 months improved the mechanical properties of the lumbar spine in ovariectomized (OVX) cynomolgus monkeys. ELD treatment increased lumbar BMD, suppressed bone turnover markers, and reduced histomorphometric parameters of both bone formation and resorption in vertebral trabecular bone. In this study, we elucidated the effects of ELD on bone quality (namely, mineralization, microarchitecture, microdamage, and bone collagen crosslinks) in OVX cynomolgus monkeys in comparison with OVX-vehicle control monkeys. Density fractionation of bone powder prepared from lumbar vertebrae revealed that ELD treatment shifted the distribution profile of bone mineralization to a higher density, and backscattered electron microscopic imaging showed improved trabecular bone connectivity in the ELD-treated groups. Higher doses of ELD more significantly reduced the amount of microdamage compared to OVX-vehicle controls. The fractionated bone powder samples were divided according to their density, and analyzed for collagen crosslinks. Enzymatic crosslinks were higher in both the high-density (≥2.0 mg/mL) and low-density (<2.0 mg/mL) fractions from the ELD-treated groups than in the corresponding fractions in the OVX-vehicle control groups. On the other hand, non-enzymatic crosslinks were lower in both the high- and low-density fractions. These observations indicated that ELD treatment stimulated the enzymatic reaction of collagen crosslinks and bone mineralization, but prevented non-enzymatic reaction of collagen crosslinks and accumulation of bone microdamage. Bone anti-resorptive agents such as bisphosphonates slow down bone remodeling so that bone mineralization, bone microdamage, and non-enzymatic collagen crosslinks all increase. Bone anabolic agents such as parathyroid hormone decrease bone mineralization and bone microdamage by stimulating bone remodeling. ELD did not fit into either category. Histological analysis indicated that the ELD treatment strongly suppressed bone resorption by reducing the number of osteoclasts, while also stimulating focal bone formation without prior bone resorption (bone minimodeling). These bidirectional activities of ELD may account for its unique effects on bone quality. Copyright © 2014. Published by Elsevier Inc.
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Cohen, Adi; Kousteni, Stavroula; Bisikirska, Brygida; Shah, Jayesh G; Manavalan, J Sanil; Recker, Robert R; Lappe, Joan; Dempster, David W; Zhou, Hua; McMahon, Donald J; Bucovsky, Mariana; Kamanda-Kosseh, Mafo; Stubby, Julie; Shane, Elizabeth
2017-06-01
We have previously reported that premenopausal women with idiopathic osteoporosis (IOP) have profound microarchitectural deficiencies and heterogeneous bone remodeling. Those with the lowest bone formation rate have higher baseline serum insulin-like growth factor-1 (IGF-1) levels and less robust response to teriparatide. Because IGF-1 stimulates bone formation and is critical for teriparatide action on osteoblasts, these findings suggest a state of IGF-1 resistance in some IOP women. To further investigate the hypothesis that osteoblast and IGF-1-related mechanisms mediate differential responsiveness to teriparatide in IOP, we studied circulating osteoblast progenitor (COP) cells and their IGF-1 receptor (IGF-1R) expression. In premenopausal women with IOP, peripheral blood mononuclear cells (PBMCs) were obtained at baseline (n = 25) and over 24 months of teriparatide treatment (n = 11). Flow cytometry was used to identify and quantify COPs (non-hematopoetic lineage cells expressing osteocalcin and RUNX2) and to quantify IGF-1R expression levels. At baseline, both the percent of PBMCs that were COPs (%COP) and COP cell-surface IGF-1R expression correlated directly with several histomorphometric indices of bone formation in tetracycline-labeled transiliac biopsies. In treated subjects, both %COP and IGF-1R expression increased promptly after teriparatide, returning toward baseline by 18 months. Although neither baseline %COP nor increase in %COP after 3 months predicted the bone mineral density (BMD) response to teriparatide, the percent increase in IGF-1R expression on COPs at 3 months correlated directly with the BMD response to teriparatide. Additionally, lower IGF-1R expression after teriparatide was associated with higher body fat, suggesting links between teriparatide resistance, body composition, and the GH/IGF-1 axis. In conclusion, these assays may be useful to characterize bone remodeling noninvasively and may serve to predict early response to teriparatide and possibly other bone formation-stimulating medications. These new tools may also have utility in the mechanistic investigation of teriparatide resistance in premenopausal IOP and perhaps in other populations. © 2017 American Society for Bone and Mineral Research. © 2017 American Society for Bone and Mineral Research.
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Dynamic Fluid Flow Mechanical Stimulation Modulates Bone Marrow Mesenchymal Stem Cells.
Hu, Minyi; Yeh, Robbin; Lien, Michelle; Teeratananon, Morgan; Agarwal, Kunal; Qin, Yi-Xian
2013-03-01
Osteoblasts are derived from mesenchymal stem cells (MSCs), which initiate and regulate bone formation. New strategies for osteoporosis treatments have aimed to control the fate of MSCs. While functional disuse decreases MSC growth and osteogenic potentials, mechanical signals enhance MSC quantity and bias their differentiation toward osteoblastogenesis. Through a non-invasive dynamic hydraulic stimulation (DHS), we have found that DHS can mitigate trabecular bone loss in a functional disuse model via rat hindlimb suspension (HLS). To further elucidate the downstream cellular effect of DHS and its potential mechanism underlying the bone quality enhancement, a longitudinal in vivo study was designed to evaluate the MSC populations in response to DHS over 3, 7, 14, and 21 days. Five-month old female Sprague Dawley rats were divided into three groups for each time point: age-matched control, HLS, and HLS+DHS. DHS was delivered to the right mid-tibiae with a daily "10 min on-5 min off-10 min on" loading regime for five days/week. At each sacrifice time point, bone marrow MSCs of the stimulated and control tibiae were isolated through specific cell surface markers and quantified by flow cytometry analysis. A strong time-dependent manner of bone marrow MSC induction was observed in response to DHS, which peaked on day 14. After 21 days, this effect of DHS was diminished. This study indicates that the MSC pool is positively influenced by the mechanical signals driven by DHS. Coinciding with our previous findings of mitigation of disuse bone loss, DHS induced changes in MSC number may bias the differentiation of the MSC population towards osteoblastogenesis, thereby promoting bone formation under disuse conditions. This study provides insights into the mechanism of time-sensitive MSC induction in response to mechanical loading, and for the optimal design of osteoporosis treatments.
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Leptin: a potential mediator for protective effects of fat mass on bone tissue.
Thomas, Thierry
2003-02-01
Body weight is among the most powerful predictors of bone status, and adipose tissue plays a substantial role in weight-related protective effects on bone. An understanding of the mechanisms underlying the relation between adipose tissue and bone may open up new perspectives for treatment. Leptin, which is known to regulate appetite and energy expenditures, may also contribute to mediate the effects of fat mass on bone. Although reported data are somewhat conflicting, there is some evidence that leptin may decrease bone formation via a central nervous effect and may stimulate both bone formation and bone resorption via direct peripheral effects on stromal precursor cells. The net result of these central and peripheral effects may depend on serum leptin levels and blood-brain barrier permeability, of which the first increase and the second decrease as obesity develops. Further work is needed to improve our understanding of these effects.
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Tanabe, Y; Dan, K; Kuriya, S; Nomura, T
1989-10-01
The effects of recombinant human interferon (IFN) alpha-2b and gamma on the bone marrow megakaryocyte progenitors (CFU-Meg) were compared between eight patients in the chronic phase of Ph1-positive chronic myelocytic leukemia (CML) and five hematologically normal patients. CFU-Meg was assayed in plasma clot culture added with phytohemagglutinin-stimulated leukocyte-conditioned medium as a source of colony stimulating activity. The average count of CFU-Meg colonies formed from the bone marrow of CML patients was 5.5 times that of normal controls. Spontaneous CFU-Meg colonies were grown in seven of eight CML patients, but in none of five controls. Colony formation by CFU-Meg in CML as well as normal bone marrow was suppressed by the two preparations of IFN in a dose dependent fashion. Their suppressive influence on colonies from CFU-Meg was comparable between CML and normal bone marrow at lower concentrations, but was less marked for CML than normal bone marrow at higher concentrations. The formation of CFU-Meg colonies from CML bone marrow was more severely suppressed by IFN-gamma than IFN-alpha-2b. Depletion of either T lymphocytes or adherent cells from the CML bone marrow cells diminished the suppressive effects of IFN-gamma, but had no influence on the effects of IFN-alpha-2b.
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NASA Technical Reports Server (NTRS)
Ma, Y. F.; Jee, W. S.; Ke, H. Z.; Lin, B. Y.; Liang, X. G.; Li, M.; Yamamoto, N.
1995-01-01
The purpose of this study was to determine if human parathyroid hormone-(1-38) (hPTH(1-38)) can restore cancellous bone mass to the established osteopenic, immobilized proximal tibial metaphyses of female rats. The right hindlimbs of 6-month-old female Sprague-Dawley rats were immobilized by bandaging the right hindlimbs to the abdomen. After 30 days of right hindlimb immobilization, the rats were subcutaneously injected with 200 micrograms hPTH(1-38)/kg/day for 15 days (short-term treatment) or 75 days (longer-term treatment). Static bone histomorphometry was performed on the primary spongiosa, and both static and dynamic histomorphometry were performed on the secondary spongiosa of the right proximal tibial metaphyses. Immobilization for 30 days without treatment decreased trabecular bone area, number, and thickness in both primary and secondary spongiosa, and induced an increase in eroded perimeter and a decrease in tissue referent-bone formation rate in the secondary spongiosa. These changes reached a new steady state thereafter. Treatment with 200 micrograms hPTH(1-38)/kg/day for 15 days, beginning 30 days after immobilization, significantly increased trabecular bone area, thickness, and number in both primary and secondary spongiosa despite continuous immobilization when compared with controls. The short-term PTH treatment (15 days) significantly increased labeling perimeter, mineral apposition rate, and tissue referent-bone formation rate in the secondary spongiosa and stimulated longitudinal bone growth as compared with the controls. Longer PTH treatment (75 days) further increased trabecular bone area, thickness, and number as compared with controls and groups given short-term PTH treatment (15 days). The bone formation indices in the secondary spongiosa of the longer-term treated rats were lower than those of the short-term treated group, but they were still higher than those of controls. Our findings indicate that PTH treatment stimulates cancellous bone formation, and restores and adds extra cancellous bone to the established, disuse-osteopenic proximal tibial metaphysis of female rats with continuously immobilized right hindlimbs. These results suggest that PTH may be useful in treating disuse-induced osteoporosis in humans.
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Thompson, Emmet M; Matsiko, Amos; Kelly, Daniel J; Gleeson, John P; O'Brien, Fergal J
2016-03-01
The lack of success associated with the use of bone grafts has motivated the development of tissue engineering approaches for bone defect repair. However, the traditional tissue engineering approach of direct osteogenesis, mimicking the process of intramembranous ossification (IMO), leads to poor vascularization. In this study, we speculate that mimicking an endochondral ossification (ECO) approach may offer a solution by harnessing the potential of hypertrophic chondrocytes to secrete angiogenic signals that support vasculogenesis and enhance bone repair. We hypothesized that stimulation of mesenchymal stem cell (MSC) chondrogenesis and subsequent hypertrophy within collagen-based scaffolds would lead to improved vascularization and bone formation when implanted within a critical-sized bone defect in vivo. To produce ECO-based constructs, two distinct scaffolds, collagen-hyaluronic acid (CHyA) and collagen-hydroxyapatite (CHA), with proven potential for cartilage and bone repair, respectively, were cultured with MSCs initially in the presence of chondrogenic factors and subsequently supplemented with hypertrophic factors. To produce IMO-based constructs, CHA scaffolds were cultured with MSCs in the presence of osteogenic factors. These constructs were subsequently implanted into 7 mm calvarial defects on Fischer male rats for up to 8 weeks in vivo. The results demonstrated that IMO- and ECO-based constructs were capable of supporting enhanced bone repair compared to empty defects. However, it was clear that the scaffolds, which were previously shown to support the greatest cartilage formation in vitro (CHyA), led to the highest new bone formation (p < 0.05) within critical-sized bone defects 8 weeks postimplantation. We speculate this to be associated with the secretion of angiogenic signals as demonstrated by the higher VEGF protein production in the ECO-based constructs before implantation leading to the greater blood vessel ingrowth. This study thus demonstrates the ability of recapitulating a developmental process of bone formation to develop tissue-engineered constructs that manifest appreciable promise for bone defect repair.
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Kobayashi, Kanichiro; Takahashi, Naoyuki; Jimi, Eijiro; Udagawa, Nobuyuki; Takami, Masamichi; Kotake, Shigeru; Nakagawa, Nobuaki; Kinosaki, Masahiko; Yamaguchi, Kyoji; Shima, Nobuyuki; Yasuda, Hisataka; Morinaga, Tomonori; Higashio, Kanji; Martin, T. John; Suda, Tatsuo
2000-01-01
Osteoclast differentiation factor (ODF, also called RANKL/TRANCE/OPGL) stimulates the differentiation of osteoclast progenitors of the monocyte/macrophage lineage into osteoclasts in the presence of macrophage colony-stimulating factor (M-CSF, also called CSF-1). When mouse bone marrow cells were cultured with M-CSF, M-CSF–dependent bone marrow macrophages (M-BMMφ) appeared within 3 d. Tartrate-resistant acid phosphatase–positive osteoclasts were also formed when M-BMMφ were further cultured for 3 d with mouse tumor necrosis factor α (TNF-α) in the presence of M-CSF. Osteoclast formation induced by TNF-α was inhibited by the addition of respective antibodies against TNF receptor 1 (TNFR1) or TNFR2, but not by osteoclastogenesis inhibitory factor (OCIF, also called OPG, a decoy receptor of ODF/RANKL), nor the Fab fragment of anti–RANK (ODF/RANKL receptor) antibody. Experiments using M-BMMφ prepared from TNFR1- or TNFR2-deficient mice showed that both TNFR1- and TNFR2-induced signals were important for osteoclast formation induced by TNF-α. Osteoclasts induced by TNF-α formed resorption pits on dentine slices only in the presence of IL-1α. These results demonstrate that TNF-α stimulates osteoclast differentiation in the presence of M-CSF through a mechanism independent of the ODF/RANKL–RANK system. TNF-α together with IL-1α may play an important role in bone resorption of inflammatory bone diseases. PMID:10637272
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Cai, J; Li, W; Sun, T; Li, X; Luo, E; Jing, D
2018-05-01
The effects of exogenous pulsed electromagnetic field (PEMF) stimulation on T1DM-associated osteopathy were investigated in alloxan-treated rabbits. We found that PEMF improved bone architecture, mechanical properties, and porous titanium (pTi) osseointegration by promoting bone anabolism through a canonical Wnt/β-catenin signaling-associated mechanism, and revealed the clinical potential of PEMF stimulation for the treatment of T1DM-associated bone complications. Type 1 diabetes mellitus (T1DM) is associated with deteriorated bone architecture and impaired osseous healing potential; nonetheless, effective methods for resisting T1DM-associated osteopenia/osteoporosis and promoting bone defect/fracture healing are still lacking. PEMF, as a safe and noninvasive method, have proven to be effective for promoting osteogenesis, whereas the potential effects of PEMF on T1DM osteopathy remain poorly understood. We herein investigated the effects of PEMF stimulation on bone architecture, mechanical properties, bone turnover, and its potential molecular mechanisms in alloxan-treated diabetic rabbits. We also developed novel nontoxic Ti2448 pTi implants with closer elastic modulus with natural bone and investigated the impacts of PEMF on pTi osseointegration for T1DM bone-defect repair. The deteriorations of cancellous and cortical bone architecture and tissue-level mechanical strength were attenuated by 8-week PEMF stimulation. PEMF also promoted osseointegration and stimulated more adequate bone ingrowths into the pore spaces of pTi in T1DM long-bone defects. Moreover, T1DM-associated reduction of bone formation was significantly attenuated by PEMF, whereas PEMF exerted no impacts on bone resorption. We also found PEMF-induced activation of osteoblastogenesis-related Wnt/β-catenin signaling in T1DM skeletons, but PEMF did not alter osteoclastogenesis-associated RANKL/RANK signaling gene expression. We reveal that PEMF improved bone architecture, mechanical properties, and pTi osseointegration by promoting bone anabolism through a canonical Wnt/β-catenin signaling-associated mechanism. This study enriches our basic knowledge for understanding skeletal sensitivity in response to external electromagnetic signals, and also opens new treatment alternatives for T1DM-associated osteopenia/osteoporosis and osseous defects in an easy and highly efficient manner.
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Bone formation within alumina tubes: effect of calcium, manganese, and chromium dopants.
Pabbruwe, Moreica B; Standard, Owen C; Sorrell, Charles C; Howlett, C Rolfe
2004-09-01
Alumina tubes (1.3mm outer diameter, 0.6mm inner diameter, 15 mm length) doped with Ca, Mn, or Cr at nominal concentrations of 0.5 and 5.0 mol% were implanted into femoral medullary canals of female rats for 16 weeks. Tissue formation within tubes was determined by histology and histomorphometry. Addition of Ca to alumina promoted hypertrophic bone formation at the advancing tissue fronts and tube entrances, and appeared to retard angiogenesis by limiting ongoing cellular migration into the tube. It is speculated that the presence of a secondary phase of calcium hexaluminate, probably having a solubility greater than that of alumina, possibly increased the level of extracellular Ca and, consequently, stimulated osteoclastic activity at the bone-ceramic interface. Addition of Mn significantly enhanced osteogenesis within the tubes. However, it is not possible to determine whether phase composition or microstructure of the ceramic was responsible for this because both were significantly altered by Mn addition. Addition of Cr to the alumina apparently stimulated bone remodelling as indicated by increased cellular activity and bone resorption at the tissue-implant interface. Cr was incorporated into the alumina as a solid solution and the tissue response was speculated to be an effect of surface chemistry rather than microstructure. The work demonstrates that doping a bioinert ceramic with small amounts of specific elements can significantly alter tissue ingrowth, differentiation, and osteogenesis within a porous implant.
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Vitamin D and gene networks in human osteoblasts
van de Peppel, Jeroen; van Leeuwen, Johannes P. T. M.
2014-01-01
Bone formation is indirectly influenced by 1,25-dihydroxyvitamin D3 (1,25D3) through the stimulation of calcium uptake in the intestine and re-absorption in the kidneys. Direct effects on osteoblasts and bone formation have also been established. The vitamin D receptor (VDR) is expressed in osteoblasts and 1,25D3 modifies gene expression of various osteoblast differentiation and mineralization-related genes, such as alkaline phosphatase (ALPL), osteocalcin (BGLAP), and osteopontin (SPP1). 1,25D3 is known to stimulate mineralization of human osteoblasts in vitro, and recently it was shown that 1,25D3 induces mineralization via effects in the period preceding mineralization during the pre-mineralization period. For a full understanding of the action of 1,25D3 in osteoblasts it is important to get an integrated network view of the 1,25D3-regulated genes during osteoblast differentiation and mineralization. The current data will be presented and discussed alluding to future studies to fully delineate the 1,25D3 action in osteoblast. Describing and understanding the vitamin D regulatory networks and identifying the dominant players in these networks may help develop novel (personalized) vitamin D-based treatments. The following topics will be discussed in this overview: (1) Bone metabolism and osteoblasts, (2) Vitamin D, bone metabolism and osteoblast function, (3) Vitamin D induced transcriptional networks in the context of osteoblast differentiation and bone formation. PMID:24782782
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Regulatory mechanism of food factors in bone metabolism and prevention of osteoporosis.
Yamaguchi, Masayoshi
2006-11-01
Aging induces a decrease in bone mass, and osteoporosis with its accompanying decrease in bone mass is widely recognized as a major public health problem. Bone loss with increasing age may be due to decreased bone formation and increased bone resorption. Pharmacologic and nutritional factors may prevent bone loss with aging, although chemical compounds in food and plants which act on bone metabolism are poorly understood. We have found that isoflavones (including genistein and daidzein), which are contained in soybeans, have a stimulatory effect on osteoblastic bone formation and an inhibitory effect on osteoclastic bone resorption, thereby increasing bone mass. Menaquinone-7, an analogue of vitamin K(2) which is abundant in fermented soybeans, has been demonstrated to stimulate osteoblastic bone formation and to inhibit osteoclastic bone resorption. Of various carotenoids, beta-cryptoxanthin, which is abundant in Satsuma mandarin (Citrus unchiu MARC), has a stimulatory effect on osteoblastic bone formation and an inhibitory effect on osteoclastic bone resorption. The supplementation of these factors has a preventive effect on bone loss induced by ovariectomy in rats, which are an animal model of osteoporosis, and their intake has been shown to have a stimulatory effect on bone mass in humans. Factors with an anabolic effect on bone metabolism were found in extracts obtained from wasabi leafstalk (Wasabi japonica MATSUM), the marine alga Sargassum horneri, and bee pollen Cistus ladaniferus. Phytocomponent p-hydroxycinnamic acid was also found to have an anabolic effect on bone metabolism. Food chemical factors thus play a role in bone health and may be important in the prevention of bone loss with increasing age.
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Dvorak, Melita M; De Joussineau, Cyrille; Carter, D Howard; Pisitkun, Trairak; Knepper, Mark A; Gamba, Gerardo; Kemp, Paul J; Riccardi, Daniela
2008-01-01
Thiazide diuretics are used, worldwide, as the first-choice drug for patients with uncomplicated hypertension. In addition to their anti-hypertensive actions, they increase bone mineral density and reduce the prevalence of fractures, indicating that thiazides may have a role in the management of postmenopausal osteoporosis. Traditionally, the bone-protective effects of thiazides have been attributed to an increase in renal calcium reabsorption, secondary to the inhibition of the sodium chloride cotransporter, NCC, expressed in the kidney distal tubule. Whether thiazides exert a direct osteoanabolic effect independently of their renal action is controversial. Here we demonstrate that freshly frozen sections of human and rat bone express NCC, principally in bone-forming cells, the osteoblasts. In primary and established culture models of osteoblasts, fetal rat calvarial (FRC) and human MG63 cells, NCC protein is virtually absent in proliferating cells while its expression is dramatically increased during differentiation. Thiazides directly stimulate the production of osteoblast markers, runt-related transcription factor 2 (runx2) and osteopontin, in the absence of a proliferative effect. Using overexpression/knockdown studies in FRC cells, we show that thiazides, but not loop diuretics, increase mineralized nodule formation acting on NCC. Overall, our study demonstrates that thiazides stimulate osteoblast differentiation and bone mineral formation independently of their renal actions. In addition to their use as part of a therapeutic treatment plan for elderly, hypertensive individuals, our discovery opens up the possibility that bone-specific drug targeting by thiazides may be developed for the prevention and treatment of osteoporosis in the patient population as a whole. PMID:17656470
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Ophoff, J; Venken, K; Callewaert, F; Boonen, S; Bouillon, R; Vanderschueren, D
2009-10-01
In this study, the role of disturbed bone mineral acquisition during puberty in the pathogenesis of osteoporosis was studied. To this end, a mouse model for senile and hypogonadal osteoporosis was used. Longitudinal follow-up showed that bone fragility in both models results from deficient bone build-up during early puberty. Male osteoporosis may result from impaired bone growth. This study characterizes the mechanisms of deficient peak bone mass acquisition in models for senile (SAMP6) and hypogonadal (orchidectomized SAMR1) osteoporosis. Bone mineral acquisition was investigated longitudinally in SAMP6 and orchidectomized SAMR1 mice (eight to ten animals per group) using peripheral quantitative computed tomography and histomorphometry. Additionally, the effects of long-term 5alpha-dihydrotestosterone (DHT) and 17beta-estradiol (E2) replacement were studied. Statistical analysis was performed using ANOVA and Student's t test. SAMP6 mice showed an early (4 weeks) medullary expansion of the cortex due to impaired endocortical bone formation (-43%). Despite compensatory periosteal bone formation (+47%), cortical thickness was severely reduced in 20-week-old SAMP6 versus SAMR1. Orchidectomy reduced periosteal apposition between 4 and 8 weeks of age and resulted in high bone turnover and less trabecular bone gain in SAMP6 and SAMR1. DHT and E2 stimulated periosteal expansion and trabecular bone in orchidectomized SAMP6 and SAMR1. E2 stimulated endocortical apposition in SAMP6. Moreover, sex steroid action occurred between 4 and 8 weeks of age. Bone fragility in both models resulted from deficient bone build-up during early puberty. DHT and E2 improved bone mass acquisition in orchidectomized animals, suggesting a role for AR and ER in male skeletal development.
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[Osteoporosis treatment in patients with hyperthyroidism].
Saito, Jun; Nishikawa, Tetsuo
2009-05-01
Childhood thyroid hormone (T3) is essential for the normal development of endochondral and intramembranous bone and plays an important role in the linear growth and maintenance of bone mass. In adult, T3 stimulates osteoclastic bone resorption mediated primarily by TR alpha and local conversion by deiodinase D2 may play a role in local activation. TSH seems to be an inhibitor of bone resorption and formation. In thyrotoxicosis patients with Graves' disease, there is increased bone remodelling, characterized by an imbalance between bone resorption and formation, which results in a decrease of bone mineral density (BMD) and an increased risk for osteoporotic fracture. Antithyroid treatment is able to reduce dramatically the bone resorption and to normalize BMD reduction. But previous hyperthyroidism is independently associated with an increased risk for fracture. Although further studies relating to the mechanism for possible impaired bone strength in these patients will be needed, bisphosphonates may be beneficial treatment for prevention of bone fractures in patients with severe risk for fractures, such as post-menopausal women.
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Kim, Beom-Su; Yang, Sun-Sik; You, Hyung-Keun; Shin, Hong-In; Lee, Jun
2018-03-01
Osteogenesis and angiogenesis, including cell-cell communication between blood vessel cells and bone cells, are essential for bone repair. Fucoidan is a chemical compound that has a variety of biological activities. It stimulates osteoblast differentiation in human mesenchymal stem cells (MSCs), which in turn induces angiogenesis. However, the mechanism by which this communication between osteoblasts and endothelial cells is mediated remains unclear. Thus, the aim of this study was to clarify the relationship between fucoidan-induced osteoblastic differentiation in MSCs and angiogenesis in endothelial cells. First, the effect was confirmed of fucoidan on osteoblast differentiation in MSCs and obtained conditioned media from these cells (Fucoidan-MSC-CM). Next, the angiogenic activity of Fucoidan-MSC-CM was investigated and it was found that it stimulated angiogenesis, demonstrated by proliferation, tube formation, migration and sprout capillary formation in human umbilical vein endothelial cells. Messenger ribonucleic acid expression and protein secretion of vascular endothelial growth factor (VEGF) were dramatically increased during fucoidan-induced osteoblast differentiation and that its angiogenic activities were reduced by a VEGF/VEGF receptor-specific binding inhibitor. Furthermore, Fucoidan-MSC-CM increased the phosphorylation of mitogen-activated protein kinase and PI3K/AKT/eNOS signalling pathway, and that its angiogenic effects were markedly suppressed by SB203580 and AKT 1/2 inhibitor. Finally, an in vivo study was conducted and it was found that fucoidan accelerated new blood vessel formation and partially promoted bone formation in a rabbit model of a calvarial bone defect. This is the first study to investigate the angiogenic effect of fucoidan-induced osteoblastic differentiation through VEGF secretion, suggesting the therapeutic potential of fucoidan for enhancing bone repair. Copyright © 2017 John Wiley & Sons, Ltd.
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Kotiya, Akhilesh A.; Bayly, Philip V.; Silva, Matthew J.
2010-01-01
Development of low-magnitude mechanical stimulation (LMMS) based treatment strategies for a variety of orthopaedic issues requires better understanding of mechano-transduction and bone adaptation. Our overall goal was to study the tissue and molecular level changes in cortical bone in response to low-strain vibration (LSV: 70 Hz, 0.5 g, 300 με) and compare these to changes in response to a known anabolic stimulus: high-strain compression (HSC: rest inserted loading, 1000 με). Adult (6–7 month) C57BL/6 mice were used for the study and non-invasive axial compression of the tibia was used as a loading model. We first studied bone adaptation at the tibial mid-diaphysis, using dynamic histomorphometry, in response to daily loading of 15 min LSV or 60 cycles HSC for 5 consecutive days. We found that bone formation rate and mineral apposition rate were significantly increased in response to HSC but not LSV. The second aim was to compare chemo-transport in response to 5 min of LSV versus 5 min (30 cycles) of HSC. Chemo-transport increased significantly in response to both loading stimuli, particularly in the medial and the lateral quadrants of the cross section. Finally, we evaluated the expression of genes related to mechano-responsiveness, osteoblast differentiation, and matrix mineralization in tibias subjected to 15 min LSV or 60 cycles HSC for 1 day (4-hour time point) or 4 consecutive days (4-day time point). The expression level of most of the genes remained unchanged in response to LSV at both time points. In contrast, the expression level of all the genes changed significantly in response to HSC at the 4-hour time point. We conclude that short-term, low-strain vibration results in increased chemo-transport, yet does not stimulate an increase in mechano-responsive or osteogenic gene expression, and cortical bone formation in tibias of adult mice. PMID:20937421
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FOXOs attenuate bone formation by suppressing Wnt signaling
Iyer, Srividhya; Ambrogini, Elena; Bartell, Shoshana M.; Han, Li; Roberson, Paula K.; de Cabo, Rafael; Jilka, Robert L.; Weinstein, Robert S.; O’Brien, Charles A.; Manolagas, Stavros C.; Almeida, Maria
2013-01-01
Wnt/β-catenin/TCF signaling stimulates bone formation and suppresses adipogenesis. The hallmarks of skeletal involution with age, on the other hand, are decreased bone formation and increased bone marrow adiposity. These changes are associated with increased oxidative stress and decreased growth factor production, which activate members of the FOXO family of transcription factors. FOXOs in turn attenuate Wnt/β-catenin signaling by diverting β-catenin from TCF- to FOXO-mediated transcription. We show herein that mice lacking Foxo1, -3, and -4 in bipotential progenitors of osteoblast and adipocytes (expressing Osterix1) exhibited increased osteoblast number and high bone mass that was maintained in old age as well as decreased adiposity in the aged bone marrow. The increased bone mass in the Foxo-deficient mice was accounted for by increased proliferation of osteoprogenitor cells and bone formation resulting from upregulation of Wnt/β-catenin signaling and cyclin D1 expression, but not changes in redox balance. Consistent with this mechanism, β-catenin deletion in Foxo null cells abrogated both the increased cyclin D1 expression and proliferation. The elucidation of a restraining effect of FOXOs on Wnt signaling in bipotential progenitors suggests that FOXO activation by accumulation of age-associated cellular stressors may be a seminal pathogenetic mechanism in the development of involutional osteoporosis. PMID:23867625
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Ha, Shin-Woo; Weitzmann, M Neale; Beck, George R
2014-06-24
We recently identified an engineered bioactive silica-based nanoparticle formulation (designated herein as NP1) that stimulates in vitro differentiation and mineralization of osteoblasts, the cells responsible for bone formation, and increases bone mineral density in young mice in vivo. The results demonstrate that these nanoparticles have intrinsic biological activity; however, the intracellular fate and a complete understanding of the mechanism(s) involved remains to be elucidated. Here we investigated the cellular mechanism(s) by which NP1 stimulates differentiation and mineralization of osteoblasts. We show that NP1 enters the cells through a caveolae-mediated endocytosis followed by stimulation of the mitogen activated protein kinase ERK1/2 (p44/p42). Our findings further revealed that NP1 stimulates autophagy including the processing of LC3β-I to LC3β-II, a key protein involved in autophagosome formation, which is dependent on ERK1/2 signaling. Using a variant of NP1 with cobalt ferrite magnetic metal core (NP1-MNP) to pull down associated proteins, we found direct binding of LC3β and p62, two key proteins involved in autophagosome formation, with silica nanoparticles. Interestingly, NP1 specifically interacts with the active and autophagosome associated form of LC3β (LC3β-II). Taken together, the stimulation of autophagy and associated signaling suggests a cellular mechanism for the stimulatory effects of silica nanoparticles on osteoblast differentiation and mineralization.
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2015-01-01
We recently identified an engineered bioactive silica-based nanoparticle formulation (designated herein as NP1) that stimulates in vitro differentiation and mineralization of osteoblasts, the cells responsible for bone formation, and increases bone mineral density in young mice in vivo. The results demonstrate that these nanoparticles have intrinsic biological activity; however, the intracellular fate and a complete understanding of the mechanism(s) involved remains to be elucidated. Here we investigated the cellular mechanism(s) by which NP1 stimulates differentiation and mineralization of osteoblasts. We show that NP1 enters the cells through a caveolae-mediated endocytosis followed by stimulation of the mitogen activated protein kinase ERK1/2 (p44/p42). Our findings further revealed that NP1 stimulates autophagy including the processing of LC3β-I to LC3β-II, a key protein involved in autophagosome formation, which is dependent on ERK1/2 signaling. Using a variant of NP1 with cobalt ferrite magnetic metal core (NP1-MNP) to pull down associated proteins, we found direct binding of LC3β and p62, two key proteins involved in autophagosome formation, with silica nanoparticles. Interestingly, NP1 specifically interacts with the active and autophagosome associated form of LC3β (LC3β-II). Taken together, the stimulation of autophagy and associated signaling suggests a cellular mechanism for the stimulatory effects of silica nanoparticles on osteoblast differentiation and mineralization. PMID:24806912
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Handschel, Jörg; Naujoks, Christian; Depprich, Rita; Lammers, Lydia; Kübler, Norbert; Meyer, Ulrich; Wiesmann, Hans-Peter
2011-07-14
Extracorporeal formation of mineralized bone-like tissue is still an unsolved challenge in tissue engineering. Embryonic stem cells may open up new therapeutic options for the future and should be an interesting model for the analysis of fetal organogenesis. Here we describe a technique for culturing embryonic stem cells (ESCs) in the absence of artificial scaffolds which generated mineralized miromasses. Embryonic stem cells were harvested and osteogenic differentiation was stimulated by the addition of dexamethasone, ascorbic acid, and ß-glycerolphosphate (DAG). After three days of cultivation microspheres were formed. These spherical three-dimensional cell units showed a peripheral zone consisting of densely packed cell layers surrounded by minerals that were embedded in the extracellular matrix. Alizarine red staining confirmed evidence of mineralization after 10 days of DAG stimulation in the stimulated but not in the control group. Transmission electron microscopy demonstrated scorching crystallites and collagenous fibrils as early indication of bone formation. These extracellular structures resembled hydroxyl apatite-like crystals as demonstrated by distinct diffraction patterns using electron diffraction analysis. The micromass culture technique is an appropriate model to form three-dimensional bone-like micro-units without the need for an underlying scaffold. Further studies will have to show whether the technique is applicable also to pluripotent stem cells of different origin. © 2011 Handschel et al; licensee BioMed Central Ltd.
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Kameda, Takashi; Ohkuma, Kazuo; Sano, Natsuki; Ogura, Hideo; Terada, Kazuto
2012-01-01
Very weak electrical, magnetic and ultrasound signal stimulations are known to promote the formation, metabolism, restoration and stability of bone and surrounding tissues after treatment and operations. We have therefore investigated the possibility of intraoral generation of electricity and magnetism by occlusal force in an in vitro study. Biting bimorph piezoelectric elements with lead zirconate titanate (PZT) using dental models generated appropriate magnetism for bone formation, i. e. 0.5-0.6 gauss, and lower electric currents and higher voltages, i. e. 2.0-6.0 μA at 10-22 V (appropriate levels are 30 μA and 1.25 V), as observed by a universal testing machine. The electric currents and voltages could be changed using amplifier circuits. These results show that intraoral generation of electricity and magnetism is possible and could provide post-operative stabilization and activation of treated areas of bone and the surrounding tissues directly and/or indirectly by electrical, magnetic and ultrasound stimulation, which could accelerate healing.
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Morcos, Mina W.; Al-Jallad, Hadil; Hamdy, Reggie
2015-01-01
Bone is one of the most dynamic tissues in the human body that can heal following injury without leaving a scar. However, in instances of extensive bone loss, this intrinsic capacity of bone to heal may not be sufficient and external intervention becomes necessary. Several techniques are available to address this problem, including autogenous bone grafts and allografts. However, all these techniques have their own limitations. An alternative method is the technique of distraction osteogenesis, where gradual and controlled distraction of two bony segments after osteotomy leads to induction of new bone formation. Although distraction osteogenesis usually gives satisfactory results, its major limitation is the prolonged duration of time required before the external fixator is removed, which may lead to numerous complications. Numerous methods to accelerate bone formation in the context of distraction osteogenesis have been reported. A viable alternative to autogenous bone grafts for a source of osteogenic cells is mesenchymal stem cells from bone marrow. However, there are certain problems with bone marrow aspirate. Hence, scientists have investigated other sources for mesenchymal stem cells, specifically adipose tissue, which has been shown to be an excellent source of mesenchymal stem cells. In this paper, the potential use of adipose stem cells to stimulate bone formation is discussed. PMID:26448947
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Pot, Michiel W; van Kuppevelt, Toin H; Gonzales, Veronica K; Buma, Pieter; IntHout, Joanna; de Vries, Rob B M; Daamen, Willeke F
2017-01-01
Bone marrow stimulation may be applied to regenerate focal cartilage defects, but generally results in transient clinical improvement and formation of fibrocartilage rather than hyaline cartilage. Tissue engineering and regenerative medicine strive to develop new solutions to regenerate hyaline cartilage tissue. This systematic review and meta-analysis provides a comprehensive overview of current literature and assesses the efficacy of articular cartilage regeneration by implantation of cell-laden versus cell-free biomaterials in the knee and ankle joint in animals after bone marrow stimulation. PubMed and EMBASE (via OvidSP) were systematically searched using tissue engineering, cartilage and animals search strategies. Included were primary studies in which cellular and acellular biomaterials were implanted after applying bone marrow stimulation in the knee or ankle joint in healthy animals. Study characteristics were tabulated and outcome data were collected for meta-analysis for studies applying semi-quantitative histology as outcome measure (117 studies). Cartilage regeneration was expressed on an absolute 0-100% scale and random effects meta-analyses were performed. Implantation of cellular biomaterials significantly improved cartilage regeneration by 18.6% compared to acellular biomaterials. No significant differences were found between biomaterials loaded with stem cells and those loaded with somatic cells. Culture conditions of cells did not affect cartilage regeneration. Cartilage formation was reduced with adipose-derived stem cells compared to other cell types, but still improved compared to acellular scaffolds. Assessment of the risk of bias was impaired due to incomplete reporting for most studies. Implantation of cellular biomaterials improves cartilage regeneration compared to acellular biomaterials.
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Shiraishi, Ayako; Sakai, Sadaoki; Saito, Hitoshi; Takahashi, Fumiaki
2014-10-01
Eldecalcitol (ELD), a 2β-hydroxypropyloxy derivative of 1α,25(OH)2D3, is a potent inhibitor of bone resorption that has demonstrated a greater effect at reducing the risk of fracture in osteoporotic patients than alfacalcidol (ALF). In the present study, we used the senescence-accelerated mouse strain P6 (SAM/P6), which has low bone mass caused by osteoblast dysfunction, to evaluate the effect of ELD on cortical bone in comparison with ALF. Four-month-old SAM/P6 mice were given either ELD (0.025 or 0.05μg/kg) or ALF (0.2 or 0.4μg/kg) by oral gavage 5 times/week for 6 weeks. Both ELD and ALF increased serum calcium (Ca) in a dose-dependent manner. Serum Ca levels in the ELD 0.05μg/kg group were comparable to those of the ALF 0.2μg/kg group. ELD 0.05μg/kg significantly improved the bone biomechanical properties of the femur compared with the vehicle control group (p<0.001) and the ALF 0.2μg/kg group (p<0.05) evaluated by 3-point bending test. The cortical area of the mid-femur in the ELD 0.05μg/kg group but not the ALF 0.2μg/kg group was significantly higher than those of the vehicle control group (p<0.001). Bone histomorphometry revealed that in the femoral endocortical surface, the suppression of bone resorption parameters (N.Oc/BS) and bone formation parameters (MS/BS) by ELD (0.05μg/kg) was greater than that by ALF (0.2μg/kg). In contrast, in the femoral periosteal surface, ELD 0.05μg/kg significantly increased bone formation parameters (BFR/BS, MS/BS) compared with the vehicle control group (p<0.05, p<0.01, respectively), whereas ALF 0.2μg/kg did not alter these parameters. These results indicate that ELD improved the biomechanical properties of femoral cortical bone not only by inhibiting endocortical bone resorption but also by stimulating the periosteal bone formation in SAM/P6 mice. This article is part of a Special Issue entitled '16th Vitamin D Workshop'. Copyright © 2013 Elsevier Ltd. All rights reserved.
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Osteogenic Activity of Locally Applied Small Molecule Drugs in a Rat Femur Defect Model
Cottrell, Jessica A.; Vales, Francis M.; Schachter, Deborah; Wadsworth, Scott; Gundlapalli, Rama; Kapadia, Rasesh; O'Connor, J. Patrick
2010-01-01
The long-term success of arthroplastic joints is dependent on the stabilization of the implant within the skeletal site. Movement of the arthroplastic implant within the bone can stimulate osteolysis, and therefore methods which promote rigid fixation or bone growth are expected to enhance implant stability and the long-term success of joint arthroplasty. In the present study, we used a simple bilateral bone defect model to analyze the osteogenic activity of three small-molecule drug implants via microcomputerized tomography (micro-CT) and histomorphometry. In this study, we show that local delivery of alendronate, but not lovastatin or omeprazole, led to significant new bone formation at the defect site. Since alendronate impedes osteoclast-development, it is theorized that alendronate treatment results in a net increase in bone formation by preventing osteoclast mediated remodeling of the newly formed bone and upregulating osteoblasts. PMID:20625499
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Parathyroid hormone-dependent signaling pathways regulating genes in bone cells
NASA Technical Reports Server (NTRS)
Swarthout, John T.; D'Alonzo, Richard C.; Selvamurugan, Nagarajan; Partridge, Nicola C.
2002-01-01
Parathyroid hormone (PTH) is an 84-amino-acid polypeptide hormone functioning as a major mediator of bone remodeling and as an essential regulator of calcium homeostasis. PTH and PTH-related protein (PTHrP) indirectly activate osteoclasts resulting in increased bone resorption. During this process, PTH changes the phenotype of the osteoblast from a cell involved in bone formation to one directing bone resorption. In addition to these catabolic effects, PTH has been demonstrated to be an anabolic factor in skeletal tissue and in vitro. As a result, PTH has potential medical application to the treatment of osteoporosis, since intermittent administration of PTH stimulates bone formation. Activation of osteoblasts by PTH results in expression of genes important for the degradation of the extracellular matrix, production of growth factors, and stimulation and recruitment of osteoclasts. The ability of PTH to drive changes in gene expression is dependent upon activation of transcription factors such as the activator protein-1 family, RUNX2, and cAMP response element binding protein (CREB). Much of the regulation of these processes by PTH is protein kinase A (PKA)-dependent. However, while PKA is linked to many of the changes in gene expression directed by PTH, PKA activation has been shown to inhibit mitogen-activated protein kinase (MAPK) and proliferation of osteoblasts. It is now known that stimulation of MAPK and proliferation by PTH at low concentrations is protein kinase C (PKC)-dependent in both osteoblastic and kidney cells. Furthermore, PTH has been demonstrated to regulate components of the cell cycle. However, whether this regulation requires PKC and/or extracellular signal-regulated kinases or whether PTH is able to stimulate other components of the cell cycle is unknown. It is possible that stimulation of this signaling pathway by PTH mediates a unique pattern of gene expression resulting in proliferation in osteoblastic and kidney cells; however, specific examples of this are still unknown. This review will focus on what is known about PTH-mediated cell signaling, and discuss the established or putative PTH-regulated pattern of gene expression in osteoblastic cells following treatment with catabolic (high) or anabolic (low) concentrations of the hormone.
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Emodin suppresses cadmium-induced osteoporosis by inhibiting osteoclast formation.
Chen, Xiao; Ren, Shuai; Zhu, Guoying; Wang, Zhongqiu; Wen, Xiaolin
2017-09-01
Environmental level of cadmium (Cd) exposure can induce bone loss. Emodin, a naturally compound found in Asian herbal medicines, could influence osteoblast/osteoclast differentiation. However, the effects of emodin on Cd-induced bone damage are not clarified. The aim of this study was to investigate the role of emodin on Cd-induced osteoporosis. Sprague-Dawley male rats were divided into three groups which were given 0mg/L, 50mg Cd/L and 50mg Cd/L plus emodin (50mg/kg body weight). Bone histological investigation, microCT analysis, metabolic biomarker determination and immunohistochemical staining were performed at the 12th week. The bone mass and bone microstructure index of rats treated with Cd were obviously lower than in control. Cd markedly enhanced the osteoclast formation compared with control. Emodin significantly abolished the Cd-induced bone microstructure damage (p<0.05), osteoclast formation and increase of tartrate-resistant acid phosphatase 5b level (p<0.05). Our data further showed that emodin attenuated the Cd-induced inhibition of osteoprotegerin expression and stimulation of receptor activator for nuclear factor-κ B ligand expression. Our data show that emodin suppresses the Cd-induced osteoporosis by inhibiting osteoclast formation. Copyright © 2017 Elsevier B.V. All rights reserved.
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Osteogenic potential of a chalcone in a critical-size defect in rat calvaria bone.
Ortolan, Xana Raquel; Fenner, Bruna Proiss; Mezadri, Telmo José; Tames, David Rivero; Corrêa, Rogério; de Campos Buzzi, Fátima
2014-07-01
This study describes the bone formation stimulated by the application of a type of chalcone to critical-size defects in rat calvarial bone. Sixty female Wistar rats were divided into 6 groups of 10 animals per group: control (no treatment), vehicle (vaseline) and the chalcone (1-phenyl-3-(4-chlorophenyl)-2-propen-1-one) suspended in vaseline at 10%. A critical-size defect of 5 mm was prepared using a trephine in the calvarial bone, after which the treatment was applied, in a single dose, according to the experimental group. The samples were evaluated macroscopically using ImageJ software, and histologically 30 and 45 days after surgery. At 30 days after surgery, there was significant bone formation (p < 0.05) in the groups treated with chalcone, compared with the other groups. Many active osteoblasts were observed adjacent to the borders of the newly formed bone tissue. 45 days after surgery in the chalcone group, the surgical defects showed complete bone closure. The results of this study suggest that chalcone has significant potential to induce the formation of new bone. Copyright © 2013 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.
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Hypergravity suppresses bone resorption in ovariectomized rats
NASA Astrophysics Data System (ADS)
Ikawa, Tesshu; Kawaguchi, Amu; Okabe, Takahiro; Ninomiya, Tadashi; Nakamichi, Yuko; Nakamura, Midori; Uehara, Shunsuke; Nakamura, Hiroaki; Udagawa, Nobuyuki; Takahashi, Naoyuki; Nakamura, Hiroaki; Wakitani, Shigeyuki
2011-04-01
The effects of gravity on bone metabolism are unclear, and little has been reported about the effects of hypergravity on the mature skeleton. Since low gravity has been shown to decrease bone volume, we hypothesized that hypergravity increases bone volume. To clarify this hypothesis, adult female rats were ovariectomized and exposed to hypergravity (2.9G) using a centrifugation system. The rats were killed 28 days after the start of loading, and the distal femoral metaphysis of the rats was studied. Bone architecture was assessed by micro-computed tomography (micro-CT) and bone mineral density was measured using peripheral quantitative CT (pQCT). Hypergravity increased the trabecular bone volume of ovariectomized rats. Histomorphometric analyses revealed that hypergravity suppressed both bone formation and resorption and increased bone volume in ovariectomized rats. Further, the cell morphology, activity, proliferation, and differentiation of osteoclasts and osteoblasts exposed to hypergravity were evaluated in vitro. Hypergravity inhibited actin ring formation in mature osteoclasts, which suggested that the osteoclast activity was suppressed. However, hypergravity had no effect on osteoblasts. These results suggest that hypergravity can stimulate an increase in bone volume by suppressing bone resorption in ovariectomized rats.
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NASA Technical Reports Server (NTRS)
Kostenuik, P. J.; Harris, J.; Halloran, B. P.; Turner, R. T.; Morey-Holton, E. R.; Bikle, D. D.
1999-01-01
Skeletal unloading decreases bone formation and osteoblast number in vivo and decreases the number and proliferation of bone marrow osteoprogenitor (BMOp) cells in vitro. We tested the ability of parathyroid hormone (PTH) to stimulate BMOp cells in vivo by treating Sprague Dawley rats (n = 32) with intermittent PTH(1-34) (1 h/day at 8 microg/100 g of body weight), or with vehicle via osmotic minipumps during 7 days of normal weight bearing or hind limb unloading. Marrow cells were flushed from the femur and cultured at the same initial density for up to 21 days. PTH treatment of normally loaded rats caused a 2.5-fold increase in the number of BMOp cells, with similar increases in alkaline phosphatase (ALP) activity and mineralization, compared with cultures from vehicle-treated rats. PTH treatment of hind limb unloaded rats failed to stimulate BMOp cell number, ALP activity, or mineralization. Hind limb unloading had no significant effect on PTH receptor mRNA or protein levels in the tibia. Direct in vitro PTH challenge of BMOp cells isolated from normally loaded bone failed to stimulate their proliferation and inhibited their differentiation, suggesting that the in vivo anabolic effect of intermittent PTH on BMOp cells was mediated indirectly by a PTH-induced factor. We hypothesize that this factor is insulin-like growth factor-I (IGF-I), which stimulated the in vitro proliferation and differentiation of BMOp cells isolated from normally loaded bone, but not from unloaded bone. These results suggest that IGF-I mediates the ability of PTH to stimulate BMOp cell proliferation in normally loaded bone, and that BMOp cells in unloaded bone are resistant to the anabolic effect of intermittent PTH therapy due to their resistance to IGF-I.
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Direct current stimulation of titanium interbody fusion devices in primates.
Cook, Stephen D; Patron, Laura P; Christakis, Petros M; Bailey, Kirk J; Banta, Charles; Glazer, Paul A
2004-01-01
The fusion rate for anterior lumbar interbody fusion (ALIF) varies widely with the use of different interbody devices and bone graft options. Adjunctive techniques such as electrical stimulation may improve the rate of bony fusion. To determine if direct current (DC) electrical stimulation of a metallic interbody fusion device enhanced the incidence or extent of anterior bony fusion. ALIF was performed using titanium alloy interbody fusion devices with and without adjunctive DC electrical stimulation in nonhuman primates. ALIF was performed through an anterolateral approach in 35 macaques with autogenous bone graft and either a titanium alloy (Ti-6Al-4V) fusion device or femoral allograft ring. The fusion devices of 19 animals received high (current density 19.6 microA/cm2) or low (current density 5.4 microA/cm2) DC electrical stimulation using an implanted generator for a 12- or 26-week evaluation period. Fusion sites were studied using serial radiographs, computed tomography imaging, nondestructive mechanical testing and qualitative and semiquantitative histology. Fusion was achieved with the titanium fusion device and autogenous bone graft. At 12 weeks, the graft was consolidating and early to moderate bridging callus was observed in and around the device. By 26 weeks, the anterior callus formation was more advanced with increased evidence of bridging trabeculations and early bone remodeling. The callus formation was not as advanced or abundant for the allograft ring group. Histology revealed the spinal fusion device had an 86% incidence of bony fusion at 26 weeks compared with a 50% fusion rate for the allograft rings. DC electrical stimulation of the fusion device had a positive effect on anterior interbody fusion by increasing both the presence and extent of bony fusion in a current density-dependent manner. Adjunctive DC electrical stimulation of the fusion device improved the rate and extent of bony fusion compared with a nonstimulated device. The fusion device was equivalent to or better than the femoral allograft ring in all evaluations. The use of adjunctive direct current electrical stimulation may provide a means of improving anterior interbody fusion.
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Strontium borate glass: potential biomaterial for bone regeneration
Pan, H. B.; Zhao, X. L.; Zhang, X.; Zhang, K. B.; Li, L. C.; Li, Z. Y.; Lam, W. M.; Lu, W. W.; Wang, D. P.; Huang, W. H.; Lin, K. L.; Chang, J.
2010-01-01
Boron plays important roles in many life processes including embryogenesis, bone growth and maintenance, immune function and psychomotor skills. Thus, the delivery of boron by the degradation of borate glass is of special interest in biomedical applications. However, the cytotoxicity of borate glass which arises with the rapid release of boron has to be carefully considered. In this study, it was found that the incorporation of strontium into borate glass can not only moderate the rapid release of boron, but also induce the adhesion of osteoblast-like cells, SaOS-2, thus significantly increasing the cyto-compatibility of borate glass. The formation of multilayers of apatite with porous structure indicates that complete degradation is optimistic, and the spread of SaOS-2 covered by apatite to form a sandwich structure may induce bone-like tissue formation at earlier stages. Therefore, such novel strontium-incorporated borosilicate may act as a new generation of biomaterial for bone regeneration, which not only renders boron as a nutritious element for bone health, but also delivers strontium to stimulate formation of new bones. PMID:20031984
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Strontium borate glass: potential biomaterial for bone regeneration.
Pan, H B; Zhao, X L; Zhang, X; Zhang, K B; Li, L C; Li, Z Y; Lam, W M; Lu, W W; Wang, D P; Huang, W H; Lin, K L; Chang, J
2010-07-06
Boron plays important roles in many life processes including embryogenesis, bone growth and maintenance, immune function and psychomotor skills. Thus, the delivery of boron by the degradation of borate glass is of special interest in biomedical applications. However, the cytotoxicity of borate glass which arises with the rapid release of boron has to be carefully considered. In this study, it was found that the incorporation of strontium into borate glass can not only moderate the rapid release of boron, but also induce the adhesion of osteoblast-like cells, SaOS-2, thus significantly increasing the cyto-compatibility of borate glass. The formation of multilayers of apatite with porous structure indicates that complete degradation is optimistic, and the spread of SaOS-2 covered by apatite to form a sandwich structure may induce bone-like tissue formation at earlier stages. Therefore, such novel strontium-incorporated borosilicate may act as a new generation of biomaterial for bone regeneration, which not only renders boron as a nutritious element for bone health, but also delivers strontium to stimulate formation of new bones.
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Effects of alkylphenols on bone metabolism in vivo and in vitro.
Hagiwara, Hiromi; Sugizaki, Toshinori; Tsukamoto, Yu; Senoh, Emi; Goto, Tadashi; Ishihara, Yoko
2008-09-01
Alkylphenols are endocrine disruptors that show estrogen-like effects in various wildlife species. However, little information is available about the action of these chemicals on bone metabolism. We investigated the effects of alkylphenols, such as nonylphenol (NP) and octylphenol (OP), on the formation of bone using several culture systems for osteoclasts and osteoblasts, as well as in vivo experiments. NP and OP dose-dependently inhibited the formation of tartrate-resistant acid phosphatase-positive multinucleated cells (osteoclasts) in cocultures of mouse spleen cells or mouse bone marrow cells with ST2 cells. However, beta-estradiol at 10(-9)M to 10(-6)M did not affect this process. In contrast, neither compound affected the proliferation and differentiation of rat calvarial osteoblast-like cells (ROB cells). When NP or OP (0.1mg/kg body weight) was administered subcutaneously to pregnant mice at 10 days, 12 days and 14 days post-coitus, fetuses at 17.5 days post-coitus showed stimulation of sternebrae bone calcification. Our findings suggest that alkylphenols have critical effects on the formation of bone by non-estrogenic effects.
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Piemontese, Marilina; Onal, Melda; Xiong, Jinhu; Wang, Yiying; Almeida, Maria; Thostenson, Jeff D; Weinstein, Robert S; Manolagas, Stavros C; O'Brien, Charles A
2015-06-01
Glucocorticoid excess decreases bone mass and strength in part by acting directly on osteoblasts and osteocytes, but the mechanisms remain unclear. Macroautophagy (herein referred to as autophagy) is a lysosome-based recycling pathway that promotes the turnover of intracellular components and can promote cell function and survival under stressful conditions. Recent studies have shown that glucocorticoids stimulate autophagy in osteocytes, suggesting that autophagy may oppose the negative actions of glucocorticoids on this cell type. To address this possibility, we compared the impact of prednisolone administration on the skeletons of adult mice in which autophagy was suppressed in osteocytes, via deletion of Atg7 with a Dmp1-Cre transgene, to their control littermates. In control mice, prednisolone increased autophagic flux in osteocyte-enriched bone as measured by LC3 conversion, but this change did not occur in the mice lacking Atg7 in osteocytes. Nonetheless, prednisolone reduced femoral cortical thickness, increased cortical porosity, and reduced bone strength to similar extents in mice with and without autophagy in osteocytes. Prednisolone also suppressed osteoblast number and bone formation in the cancellous bone of control mice. As shown previously, Atg7 deletion in osteocytes reduced osteoblast number and bone formation in cancellous bone, but these parameters were not further reduced by prednisolone administration. In cortical bone, prednisolone elevated osteoclast number to a similar extent in both genotypes. Taken together, these results demonstrate that although glucocorticoids stimulate autophagy in osteocytes, suppression of autophagy in this cell type does not worsen the negative impact of glucocorticoids on the skeleton. Published by Elsevier Inc.
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Piemontese, Marilina; Onal, Melda; Xiong, Jinhu; Wang, Yiying; Almeida, Maria; Thostenson, Jeff D.; Weinstein, Robert S.; Manolagas, Stavros C.; O’Brien, Charles A.
2015-01-01
Glucocorticoid excess decreases bone mass and strength in part by acting directly on osteoblasts and osteocytes, but the mechanisms remain unclear. Macroautophagy (herein referred to as autophagy) is a lysosome-based recycling pathway that promotes the turnover of intracellular components and can promote cell function and survival under stressful conditions. Recent studies have shown that glucocorticoids stimulate autophagy in osteocytes, suggesting that autophagy may oppose the negative actions of glucocorticoids on this cell type. To address this possibility, we compared the impact of prednisolone administration on the skeletons of adult mice in which autophagy was suppressed in osteocytes, via deletion of Atg7 with a Dmp1-Cre transgene, to their control littermates. In control mice, prednisolone increased autophagic flux in osteocyte-enriched bone as measured by LC3 conversion, but this change did not occur in the mice lacking Atg7 in osteocytes. Nonetheless, prednisolone reduced femoral cortical thickness, increased cortical porosity, and reduced bone strength to similar extents in mice with and without autophagy in osteocytes. Prednisolone also suppressed osteoblast number and bone formation in the cancellous bone of control mice. As shown previously, Atg7 deletion in osteocytes reduced osteoblast number and bone formation in cancellous bone, but these parameters were not further reduced by prednisolone administration. In cortical bone, prednisolone elevated osteoclast number to a similar extent in both genotypes. Taken together, these results demonstrate that although glucocorticoids stimulate autophagy in osteocytes, suppression of autophagy in this cell type does not worsen the negative impact of glucocorticoids on the skeleton. PMID:25700544
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NASA Technical Reports Server (NTRS)
Doty, S. B.
1984-01-01
Rats which were subjected to spaceflight for 2-4 weeks showed considerable loss in ability to form new bone. Animals which are placed into nonweight bearing positions, as a model to simulate the absence of gravity here on the Earth's surface. Show a similar decline in new bone formation. It is suggested that the mechanisms underlying these changes may be the result of reduced transmission of gravitational force to the skeletal cells.
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De Wilde, Anne; Maria Rassi, Claudia; Cournot, Giulia; Colin, Colette; Lacroix, Herminie C; Chaumaz, Gilles; Coxam, Veronique; Bennetau-Pelissero, Catherine; Pointillart, Alain; Lieberherr, Michele
2007-07-01
Food containing soybeans provide isoflavone phytoestrogens that can preserve bone mass in postmenopausal women, and prevent bone loss in ovariectomized rats. But their effects on bone remain unclear, particularly on bone formation during growth. Two groups of eight pre-pubertal piglets were fed a basal or an isoflavone-enriched (S800) diet for 6 weeks. The S800 diet contained 800 mg SoyLifetrade mark/kg, providing 2.8 mg isoflavones/kg body weight/day. Several bones were collected and tested for bone strength and density. Bone marrow was collected from humeri together with blood samples and genital tracts. The plasma concentrations of isoflavones were increased in the pigs fed S800, but growth rate, body weight, plasma bone markers, bone mineral density, and strength were all unaffected. In contrast, cultured stromal cells from S800 pigs had more alkaline phosphatase-rich cells and mineralized nodules, secreted more osteocalcin, osteoprotegerin and RANK-L, synthesized more osteoprotegerin, and RANK-L. Cultured mononucleated nonadherent bone marrow cells from S800 pigs developed fewer tartrate-resistant acid phosphatase mononucleated cells (osteoclast progenitors) when cultured with 1,25(OH)(2)D(3), and resorbed a smaller area of dentine slices. Freshly isolated bone marrow osteoclast progenitors from S800 pigs had more caspase-3 cleavage activity, and synthesized less RANK. Both osteoclast and osteoblast progenitors had ERalpha and ERbeta, whose syntheses were stimulated by the S800 diet. The S800 piglets had heavier ovaries with more follicles, but their uterus weight was unaffected. We conclude that dietary isoflavones have no detectable effect on the bone mass of growing female piglets, but act on bone marrow osteoprogenitors via ERs--mainly ERbeta, and stimulate ovary development.
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Krieger, Nancy S; Bushinsky, David A
2017-10-01
Serum fibroblast growth factor 23 (FGF23) increases progressively in chronic kidney disease (CKD) and is associated with increased mortality. FGF23 is synthesized in osteoblasts and osteocytes; however, the factors regulating its production are not clear. Patients with CKD have decreased renal acid excretion leading to metabolic acidosis (MET). During MET, acid is buffered by bone with release of mineral calcium (Ca) and phosphate (P). MET increases intracellular Ca signaling and cyclooxygenase 2 (COX2)-induced prostaglandin production in the osteoblast, leading to decreased bone formation and increased bone resorption. We found that MET directly stimulates FGF23 in mouse bone organ cultures and primary osteoblasts. We hypothesized that MET increases FGF23 through similar pathways that lead to bone resorption. Neonatal mouse calvariae were incubated in neutral (NTL, pH = 7.44, Pco 2 = 38 mmHg, [HCO 3 - ] = 27 mM) or acid (MET, pH = 7.18, Pco 2 = 37 mmHg, [HCO 3 - ] = 13 mM) medium without or with 2-APB (50 μM), an inhibitor of intracellular Ca signaling or NS-398 (1 μM), an inhibitor of COX2. Each agent significantly inhibited MET stimulation of medium FGF23 protein and calvarial FGF23 RNA as well as bone resorption at 48 h. To exclude the potential contribution of MET-induced bone P release, we utilized primary calvarial osteoblasts. In these cells each agent inhibited MET stimulation of FGF23 RNA expression at 6 h. Thus stimulation of FGF23 by MET in mouse osteoblasts utilizes the same initial signaling pathways as MET-induced bone resorption. Therapeutic interventions directed toward correction of MET, especially in CKD, have the potential to not only prevent bone resorption but also lower FGF23 and perhaps decrease mortality. Copyright © 2017 the American Physiological Society.
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Wnt signaling in bone formation and its therapeutic potential for bone diseases
Kim, Jeong Hwan; Liu, Xing; Wang, Jinhua; Chen, Xiang; Zhang, Hongyu; Kim, Stephanie H.; Cui, Jing; Li, Ruidong; Zhang, Wenwen; Kong, Yuhan; Zhang, Jiye; Shui, Wei; Lamplot, Joseph; Rogers, Mary Rose; Zhao, Chen; Wang, Ning; Rajan, Prashant; Tomal, Justin; Statz, Joseph; Wu, Ningning; Luu, Hue H.; Haydon, Rex C.
2013-01-01
The Wnt signaling pathway plays an important role not only in embryonic development but also in the maintenance and differentiation of the stem cells in adulthood. In particular, Wnt signaling has been shown as an important regulatory pathway in the osteogenic differentiation of mesenchymal stem cells. Induction of the Wnt signaling pathway promotes bone formation while inactivation of the pathway leads to osteopenic states. Our current understanding of Wnt signaling in osteogenesis elucidates the molecular mechanisms of classic osteogenic pathologies. Activating and inactivating aberrations of the canonical Wnt signaling pathway in osteogenesis results in sclerosteosis and osteoporosis respectively. Recent studies have sought to target the Wnt signaling pathway to treat osteogenic disorders. Potential therapeutic approaches attempt to stimulate the Wnt signaling pathway by upregulating the intracellular mediators of the Wnt signaling cascade and inhibiting the endogenous antagonists of the pathway. Antibodies against endogenous antagonists, such as sclerostin and dickkopf-1, have demonstrated promising results in promoting bone formation and fracture healing. Lithium, an inhibitor of glycogen synthase kinase 3β, has also been reported to stimulate osteogenesis by stabilizing β catenin. Although manipulating the Wnt signaling pathway has abundant therapeutic potential, it requires cautious approach due to risks of tumorigenesis. The present review discusses the role of the Wnt signaling pathway in osteogenesis and examines its targeted therapeutic potential. PMID:23514963
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Zhang, Wenjing; Tian, Yu; He, Hongyan; Chen, Rui; Ma, Yifan; Guo, Han; Yuan, Yuan; Liu, Changsheng
2016-03-01
Strontium (Sr(2+)) has pronounced effects on stimulating bone formation and inhibiting bone resorption in bone regeneration. In this current study, the effect and the underlying mechanism involved of Sr(2+) on the biological activity of bone morphogenetic protein-2 (BMP-2) were studied in detail with pluripotent skeletal muscle myogenic progenitor C2C12 model cell line. The results indicated that Sr(2+) could bind recombinant human BMP-2 (rhBMP-2) rapidly, even in the presence of Ca(2+) and Mg(2+), and inhibited rhBMP-2-induced osteogenic differentiation in vitro and osteogenetic efficiency in vivo. Further studies demonstrated that Sr(2+) treatment undermined the binding capacity of rhBMP-2 with its receptor BMPRIA and thus attenuated Smad 1/5/8 phosphorylation without affecting their dephosphorylation in C2C12 cells. Furthermore, circular dichroism spectroscopy, fluorescence spectroscopy and X-ray photoelectron spectroscopy all revealed that the inhibitory effect of Sr(2+) on the rhBMP-2 osteogenic activity was associated with the formation of Sr-rhBMP-2 complex and ensuing enhancement of β-sheet structure. Our work suggests the activity of rhBMP-2 to induce osteogenic differentiation was decreased by directly interaction with free Sr ions in solution, which should provide guide and assist for development of BMP-2-based materials for bone regeneration. Due to easy denaturation and ensuing the reduced activity of rhBMP-2, preserving/enhancing the capacity of rhBMP-2 to induce osteogenic differentiation is of critical importance in developing the protein-based therapy. Cations as effective elements influence the conformation and thereby the bioactivity of protein. Strontium (Sr(2+)), stimulating bone formation and inhibiting bone resorption, has been incorporated into biomaterials/scaffold to improve the bioactivity for bone-regeneration applications. However, Sr(2+)-induced changes in the conformation and bioactivity of BMP-2 have never been investigated. In this study, the formation of Sr-rhBMP-2 complex inhibited the osteogenic differentiation in vitro and osteogenetic efficiency in vivo through the inhibition of BMP/Smad signaling pathway, providing guidance for development of Sr-containing BMP-2-based bone scaffold/matrice and other Sr-dopped protein therapy. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
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Pathophysiology and new strategies for the treatment of Legg-Calvé-Perthes disease.
Kim, Harry K W
2012-04-04
Legg-Calvé-Perthes disease is a juvenile form of idiopathic osteonecrosis of the femoral head that can lead to permanent femoral head deformity and premature osteoarthritis. According to two recent multicenter, prospective cohort studies, current nonoperative and operative treatments have modest success rates of producing a good outcome with a spherical femoral head in older children with Legg-Calvé-Perthes disease. Experimental studies have revealed that the immature femoral head is mechanically weakened following ischemic necrosis. Increased bone resorption and delayed new bone formation, in combination with continued mechanical loading of the hip, contribute to the pathogenesis of the femoral head deformity. Biological treatment strategies to improve the healing process by decreasing bone resorption and stimulating bone formation appear promising in nonhuman preclinical studies.
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Baier, Martin; Staudt, Patric; Klein, Roman; Sommer, Ulrike; Wenz, Robert; Grafe, Ingo; Meeder, Peter Jürgen; Nawroth, Peter P; Kasperk, Christian
2013-06-07
Calcium phosphate cements are used frequently in orthopedic and dental surgeries. Strontium-containing drugs serve as systemic osteoblast-activating medication in various clinical settings promoting mechanical stability of the osteoporotic bone. Strontium-containing calcium phosphate cement (SPC) and calcium phosphate cement (CPC) were compared regarding their local and systemic effects on bone tissue in a standard animal model for osteoporotic bone. A bone defect was created in the distal femoral metaphysis of 60 ovariectomized Sprague-Dawley rats. CPC and SPC were used to fill the defects in 30 rats in each group. Local effects were assessed by histomorphometry at the implant site. Systemic effects were assessed by bone mineral density (BMD) measurements at the contralateral femur and the spine. Faster osseointegration and more new bone formation were found for SPC as compared to CPC implant sites. SPC implants exhibited more cracks than CPC implants, allowing more bone formation within the implant. Contralateral femur BMD and spine BMD did not differ significantly between the groups. The addition of strontium to calcium phosphate stimulates bone formation in and around the implant. Systemic release of strontium from the SPC implants did not lead to sufficiently high serum strontium levels to induce significant systemic effects on bone mass in this rat model.
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In vitro bioactivity of novel tricalcium silicate ceramics.
Zhao, Wenyuan; Chang, Jiang; Wang, Junying; Zhai, Wanyin; Wang, Zheng
2007-05-01
In this study, bone-like apatite-formation ability of tricalcium silicate (Ca(3)SiO(5)) ceramics in simulated body fluid (SBF) was evaluated and the in vitro degradability was investigated by soaking in Ringer's solution. The effect of ionic products from Ca(3)SiO(5) dissolution on osteobalsts proliferation was investigated. The result indicated that hydroxyapatite (HA) was formed on the surface of the Ca(3)SiO(5) ceramics after soaking in SBF for 1 day, and Ca(3)SiO(5) ceramics could degraded in Ringer's solution. The Si ions from Ca(3)SiO(5) dissolution at certain concentration range significantly stimulated osteoblasts proliferation. Our results show that Ca(3)SiO(5) ceramics possess bone-like apatite-formation ability and degradability, and can release soluble ionic products to stimulate cell proliferation.
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[Research advances of fluid bio-mechanics in bone].
Chen, Zebin; Huo, Bo
2017-04-01
It has been found for more than one century that when experiencing mechanical loading, the structure of bone will adapt to the changing mechanical environment, which is called bone remodeling. Bone remodeling is charaterized as two processes of bone formation and bone resorption. A large number of studies have confirmed that the shear stress is resulted from interstitial fluid flow within bone cavities under mechanical loading and it is the key factor of stimulating the biological responses of bone cells. This review summarizes the major research progress during the past years, including the biological response of bone cells under fluid flow, the pressure within bone cavities, the theoretical modeling, numerical simulation and experiments about fluid flow within bone, and finally analyzes and predicts the possible tendency in this field in the future.
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Yao, Wei; Evan Lay, Yu-An; Kot, Alexander; Liu, Ruiwu; Zhang, Hongliang; Chen, Haiyan; Lam, Kit; Lane, Nancy E.
2017-01-01
Mesenchymal stem cell (MSC) transplantation has been tested in animal and clinical fracture studies. We have developed a bone-seeking compound, LLP2A-Alendronate (LLP2A-Ale) that augments MSC homing to bone. The purpose of this study was to determine whether treatment with LLP2A-Ale or a combination of LLP2A-Ale and MSCs would accelerate bone healing in a mouse closed fracture model and if the effects are sex dependent. A right mid-femur fracture was induced in two-month-old osterix-mCherry (Osx-mCherry) male and female reporter mice. The mice were subsequently treated with placebo, LLP2A-Ale (500 µg/kg, IV), MSCs derived from wild-type female Osx-mCherry adipose tissue (ADSC, 3 × 105, IV) or ADSC + LLP2A-Ale. In phosphate buffered saline-treated mice, females had higher systemic and surface-based bone formation than males. However, male mice formed a larger callus and had higher volumetric bone mineral density and bone strength than females. LLP2A-Ale treatment increased exogenous MSC homing to the fracture gaps, enhanced incorporation of these cells into callus formation, and stimulated endochondral bone formation. Additionally, higher engraftment of exogenous MSCs in fracture gaps seemed to contribute to overall fracture healing and improved bone strength. These effects were sex-independent. There was a sex-difference in the rate of fracture healing. ADSC and LLP2A-Ale combination treatment was superior to on callus formation, which was independent of sex. Increased mobilization of exogenous MSCs to fracture sites accelerated endochondral bone formation and enhanced bone tissue regeneration. PMID:27334693
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Komatsu, Jun; Nagura, Nana; Iwase, Hideaki; Igarashi, Mamoru; Ohbayashi, Osamu; Nagaoka, Isao; Kaneko, Kazuo
2018-01-01
Grafting β-tricalcium phosphate (TCP) is a well-established method for restoring bone defects; however, there is concern that the mechanical stability of the grafted β-TCP is not maintained during bone translation. Teriparatide has an anabolic effect, stimulating bone formation and increasing bone mineral density for the treatment of osteoporosis. The aim of the present study was to evaluate the effect of intermittent teriparatide treatment on changes in bone grafted with β-TCP using a rabbit bone defect model. Bone defects (5×15 mm) were created in the distal femoral condyle of Japanese white rabbits, and β-TCP granules of two different total porosities were manually grafted. Teriparatide (40 µg/kg) or 0.2% rabbit serum albumin solution as a vehicle control was subcutaneously injected three times per week following the surgery. At 4 or 8 weeks post-surgery, serum samples were obtained and the levels of γ-carboxylated osteocalcin (Gla-OC) were quantified using ELISA. Histomorphometry was also performed using sections of graft sites following staining for tartrate resistant acid phosphatase. Activity and mechanical strength (maximum shear strength, maximum shear stiffness and total energy absorption) were evaluated using an axial push-out load to failure test. Teriparatide treatment significantly increased (P<0.05) the serum levels of Gla-OC, a specific marker for bone formation, suggesting that teriparatide enhances bone formation in β-TCP-grafted rabbits. Furthermore teriparatide increased the degradation of β-TCP by bone remodeling (P<0.05) and promoted the formation of new bone following application of the graft compared with the control group (P<0.01). Furthermore, teriparatide suppressed the reduction in mechanical strength (P<0.05) during bone translation in bone defects grafted with β-TCP. The results of the present study demonstrate that teriparatide is effective in maintaining the mechanical stability of grafted β-TCP, possibly by promoting new bone formation. PMID:29387179
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Briolay, A.; Lencel, P.; Bessueille, L.
2013-01-18
Highlights: ► Ankylosing spondylitis (AS) leads to bone fusions and ankylosis. ► TNF-α stimulates osteoblasts through growth factors in AS. ► We compare the involvement of canonical vs non-canonical Wnt signaling. ► Canonical Wnt signaling is not involved in TNF-α effects in differentiating hMSCs. ► TNF-α stimulates osteoblasts through Wnt5a autocrine secretion in hMSCs. -- Abstract: Although anti-tumor necrosis factor (TNF)-α treatments efficiently block inflammation in ankylosing spondylitis (AS), they are inefficient to prevent excessive bone formation. In AS, ossification seems more prone to develop in sites where inflammation has resolved following anti-TNF therapy, suggesting that TNF-α indirectly stimulates ossification.more » In this context, our objectives were to determine and compare the involvement of Wnt proteins, which are potent growth factors of bone formation, in the effects of TNF-α on osteoblast function. In human mesenchymal stem cells (MSCs), TNF-α significantly increased the levels of Wnt10b and Wnt5a. Associated with this effect, TNF-α stimulated tissue-non specific alkaline phosphatase (TNAP) and mineralization. This effect was mimicked by activation of the canonical β-catenin pathway with either anti-Dkk1 antibodies, lithium chloride (LiCl) or SB216763. TNF-α reduced, and activation of β-catenin had little effect on expression of osteocalcin, a late marker of osteoblast differentiation. Surprisingly, TNF-α failed to stabilize β-catenin and Dkk1 did not inhibit TNF-α effects. In fact, Dkk1 expression was also enhanced in response to TNF-α, perhaps explaining why canonical signaling by Wnt10b was not activated by TNF-α. However, we found that Wnt5a also stimulated TNAP in MSCs cultured in osteogenic conditions, and increased the levels of inflammatory markers such as COX-2. Interestingly, treatment with anti-Wnt5a antibodies reduced endogenous TNAP expression and activity. Collectively, these data suggest that increased levels of Dkk1 may blunt the autocrine effects of Wnt10b, but not that of Wnt5a, acting through non-canonical signaling. Thus, Wnt5a may be potentially involved in the effects of inflammation on bone formation.« less
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Liu, Sean Shih-Yao; Xu, Haisong; Sun, Jun; Kontogiorgos, Elias; Whittington, Patrick R; Misner, Kenner G; Kyung, Hee-Moon; Buschang, Peter H; Opperman, Lynne A
2013-08-01
Suture expansion stimulates bone growth to correct craniofacial deficiencies but has a high potential of treatment relapse. The objective of this study was to investigate whether there is a dose-dependent relationship between the recombinant human bone morphogenetic protein-2 (rhBMP-2) and bone formation during suture expansion. Fifty 6-week-old male New Zealand white rabbits were randomly assigned to 5 groups to receive 0 (control), 0.01, 0.025, 0.1, or 0.4 mg/mL of rhBMP-2 delivered by absorbable collagen sponge placed over the interfrontal suture. The suture was expanded for 33 days by 200 g of constant force via a spring anchored with 2 miniscrew implants. Distance of suture expansion, suture volume, and cross-sectional area after expansion were measured using radiographs with bone markers and microcomputed tomography. Suture widths and mineralization appositional rates were calculated based on the widths between bone labels under an epifluorescent microscope. Software (Multilevel Win 2.0; University of Bristol, Bristol, United Kingdom) was used to model distance of suture expansion over time as polynomials to compare group differences. Wilcoxon signed rank tests were performed to compare the suture volume and cross-sectional area, mineral apposition rate, and suture width between groups. The significance level was set at P = 0.05. Whereas the sutures were expanded in all groups, sutures were expanded by significantly greater amounts in the control and the 0.01 mg/mL groups without fusing the sutures than in the 0.025, 0.1, and 0.4 mg/mL groups with fusing sutures. Compared with the controls, the 0.01 mg/mL group showed significantly lower suture volumes, cross-sectional areas, and suture widths after expansion. The mineral apposition rate was significantly higher in the 0.01 mg/mL group than in the controls from days 10 to 30. The 0.01 mg/mL dose of rhBMP-2 delivered by absorbable collagen sponge can stimulate bone formation at the bony edges of the suture during suture expansion; however, higher concentrations cause suture fusion. With an appropriate concentration, rhBMP-2 might facilitate suture expansion for clinical uses. Copyright © 2013 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.
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van Kuppevelt, Toin H.; Gonzales, Veronica K.; Buma, Pieter; IntHout, Joanna; de Vries, Rob B.M.
2017-01-01
Bone marrow stimulation may be applied to regenerate focal cartilage defects, but generally results in transient clinical improvement and formation of fibrocartilage rather than hyaline cartilage. Tissue engineering and regenerative medicine strive to develop new solutions to regenerate hyaline cartilage tissue. This systematic review and meta-analysis provides a comprehensive overview of current literature and assesses the efficacy of articular cartilage regeneration by implantation of cell-laden versus cell-free biomaterials in the knee and ankle joint in animals after bone marrow stimulation. PubMed and EMBASE (via OvidSP) were systematically searched using tissue engineering, cartilage and animals search strategies. Included were primary studies in which cellular and acellular biomaterials were implanted after applying bone marrow stimulation in the knee or ankle joint in healthy animals. Study characteristics were tabulated and outcome data were collected for meta-analysis for studies applying semi-quantitative histology as outcome measure (117 studies). Cartilage regeneration was expressed on an absolute 0–100% scale and random effects meta-analyses were performed. Implantation of cellular biomaterials significantly improved cartilage regeneration by 18.6% compared to acellular biomaterials. No significant differences were found between biomaterials loaded with stem cells and those loaded with somatic cells. Culture conditions of cells did not affect cartilage regeneration. Cartilage formation was reduced with adipose-derived stem cells compared to other cell types, but still improved compared to acellular scaffolds. Assessment of the risk of bias was impaired due to incomplete reporting for most studies. Implantation of cellular biomaterials improves cartilage regeneration compared to acellular biomaterials. PMID:29093996
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Choudhary, Shilpa; Blackwell, Katherine; Voznesensky, Olga; Roy, Abhijit Deb; Pilbeam, Carol
2014-01-01
Intermittent PTH is the major anabolic therapy for osteoporosis while continuous PTH causes bone loss. PTH acts on the osteoblast (OB) lineage to regulate bone resorption and formation. PTH also induces cyclooxygenase-2 (COX-2), producing prostaglandin E2 (PGE2) that can act on both OBs and osteoclasts (OCs). Because intermittent PTH is more anabolic in Cox-2 knockout (KO) than wild type (WT) mice, we hypothesized COX-2 might contribute to the effects of continuous PTH by suppressing PTH-stimulated differentiation of mesenchymal stem cells into OBs. We compared effects of continuous PTH on bone marrow stromal cells (BMSCs) and primary OBs (POBs) from Cox-2 KO mice, mice with deletion of PGE2 receptors (Ptger4 and Ptger2 KO mice), and WT controls. PTH increased OB differentiation in BMSCs only in the absence of COX-2 expression or activity. In the absence of COX-2, PTH stimulated differentiation if added during the first week of culture. In Cox-2 KO BMSCs, PTH-stimulated differentiation was prevented by adding PGE2 to cultures. Co-culture of POBs with M-CSF-expanded bone marrow macrophages (BMMs) showed that the inhibition of PTH-stimulated OB differentiation required not only COX-2 or PGE2 but also BMMs. Sufficient PGE2 to mediate the inhibitory effect was made by either WT POBs or WT BMMs. The inhibitory effect mediated by COX-2/PGE2 was transferred by conditioned media from RANKL-treated BMMs and could be blocked by osteoprotegerin, which interferes with RANKL binding to its receptor on OC lineage cells. Deletion of Ptger4, but not Ptger2, in BMMs prevented the inhibition of PTH-stimulated OB differentiation. As expected, PGE2 also stimulated OB differentiation, but when given in combination with PTH, the stimulatory effects of both were abrogated. These data suggest that PGE2, acting via EP4R on BMMs committed to the OC lineage, stimulated secretion of a factor or factors that acted to suppress PTH-stimulated OB differentiation. This suppression of OB differentiation could contribute to the bone loss seen with continuous PTH in vivo. PMID:23639875
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[Development, physiology, and cell activity of bone].
de Baat, P; Heijboer, M P; de Baat, C
2005-07-01
Bones are of crucial importance for the human body, providing skeletal support, serving as a home for the formation of haematopoietic cells, and reservoiring calcium and phosphate. Long bones develop by endochondral ossification. Flat bones develop by intramembranous ossification. Bone tissue contains hydroxyapatite and various extracellular proteins, producing bone matrix. Two biological mechanisms, determining the strength of bone, are modelling and remodelling. Modelling can change bone shape and size through bone formation by osteoblasts at some sites and through bone destruction by osteoclasts at other sites. Remodelling is bone turnover, also performed by osteoclasts and osteoblasts. The processes of modelling and remodelling are induced by mechanical loads, predominantly muscle loads. Osteoblasts develop from mesenchymal stem cells. Many stimulating factors are known to activate the differentiation. Mature osteoblasts synthesize bone matrix and may further differentiate into osteocytes. Osteocytes maintain structural bone integrity and allow bone to adapt to any mechanical and chemical stimulus. Osteoclasts derive from haematopoietic stem cells. A number of transcription and growth factors have been identified essential for osteoclast differentiation and function. Finally, there is a complex interaction between osteoblasts and osteoclasts. Bone destruction starts by attachment of osteoclasts to the bone surface. Following this, osteoclasts undergo specific morphological changes. The process of bone destruction starts by acid dissolution of hydroxyapatite. After that osteoclasts start to destruct the organic matrix.
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NASA Technical Reports Server (NTRS)
Ma, Y. F.; Jee, W. S. S.; Ke, H. Z.; Lin, B. Y.; Liang, X. G.; Li, M.; Yamamoto, N.
1994-01-01
The purpose of this study was to determine if human parathyroid hormone-(1-38) (PTH) can restore cancellous bone mass to the established osteopenic, immobilized proximal tibial metaphyses (PTM) of female rats. The right hindlimbs of six-month-old female Sprague-Dawley rats were immobilized by bandaging the right hindlimbs to the abdomen. After 30 days of right hindlimb immobilization (RHLI), the rats were subcutaneously injected with 200 microgram hPTH(1-38)/kg/day for 15 (short-term) or 75 (longer-term) days. Static bone histomorphometry was performed on the primary spongiosa, while both static and dynamic histomorphometry were performed on the secondary spongiosa of the right PTM. Immobilization for 30 days without treatment decreased trabecular bone area, number and thickness in both primary and secondary spongiosa, and induced an increase in eroded perimeter and a decrease in tissue referent-bone formation rate (BFR/TV) in the secondary spongios. These changes reached a new steady state thereafter. Treatment with 200 microgram hPTH(1-38)/kg/day for 15 days, beginning at 30 days post immobilization (IM), significantly increased trabecular bone area, thickness and number in both primary and secondary spongiosa despite continuous IM when compared to the age-related and IM controls. The short-term (15 days) PTH treatment significantly increased labeling perimeter, mineral apposition rate and BFR/TV in the secondary spongiosa and stimulated longitudinal bone growth as compared to the age-related and IM controls. PTH treatment for longer-term (75 days) further increased trabecular bone area, thickness and number as compared to aging and IM controls and short-term (15 days) PTH treated groups. The bone formation indices in the secondary spongiosa of these longer-term treated rats were lower than that of short-term (15 days) PTH treated group, but they were still higher than those of IM and age-related controls. Our findings indicate that PTH treatment stimulates cancellous bone formation, restores and adds extra cancellous bone to the established, disuse-osteopenic proximal tibial metaphysis of continuously RHLI female rats. These results suggest that PTH may be a useful agent in treatment disuse-induced osteoporosis in humans.
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Hsiao, Edward C.; Millard, Susan M.; Louie, Alyssa; Huang, Yong; Conklin, Bruce R.; Nissenson, Robert A.
2010-01-01
Age-dependent changes in skeletal growth play important roles in regulating skeletal expansion and in the course of many diseases affecting bone. How G protein-coupled receptor (GPCR) signaling affects these changes is poorly understood. Previously, we described a mouse model expressing Rs1, an engineered receptor with constitutive Gs activity. Rs1 expression in osteoblasts from gestation induced a dramatic age-dependent increase in trabecular bone with features resembling fibrous dysplasia; however, these changes were greatly minimized if Rs1 expression was delayed until after puberty. To further investigate whether ligand-induced activation of the Gs-GPCR pathway affects bone formation in adult mice, we activated Rs1 in adult mice with the synthetic ligand RS67333 delivered continuously via an osmotic pump or intermittently by daily injections. We found that osteoblasts from adult animals can be stimulated to form large amounts of bone, indicating that adult mice are sensitive to the dramatic bone- forming actions of Gs signaling in osteoblasts. In addition, our results show that intermittent and continuous activation of Rs1 led to structurally similar but quantitatively different degrees of trabecular bone formation. These results indicate that activation of a Gs-coupled receptor in osteoblasts of adult animals by either intermittent or continuous ligand administration can increase trabecular bone formation. In addition, osteoblasts located at the bone epiphyses may be more responsive to Gs signaling than osteoblasts at the bone diaphysis. This model provides a powerful tool for investigating the effects of ligand-activated Gs-GPCR signaling on dynamic bone growth and remodeling. PMID:20150184
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Hu, Bin; El Haj, Alicia J; Dobson, Jon
2013-01-01
Mechanical cues are employed to promote stem cell differentiation and functional tissue formation in tissue engineering and regenerative medicine. We have developed a Magnetic Force Bioreactor (MFB) that delivers highly targeted local forces to cells at a pico-newton level, utilizing magnetic micro- and nano-particles to target cell surface receptors. In this study, we investigated the effects of magnetically targeting and actuating specific two mechanical-sensitive cell membrane receptors—platelet-derived growth factor receptor α (PDGFRα) and integrin ανβ3. It was found that a higher mineral-to-matrix ratio was obtained after three weeks of magneto-mechanical stimulation coupled with osteogenic medium culture by initially targeting PDGFRα compared with targeting integrin ανβ3 and non-treated controls. Moreover, different initiation sites caused a differentiated response profile when using a 2-day-lagged magneto-mechanical stimulation over culture periods of 7 and 12 days). However, both resulted in statistically higher osteogenic marker genes expression compared with immediate magneto-mechanical stimulation. These results provide insights into important parameters for designing appropriate protocols for ex vivo induced bone formation via magneto-mechanical actuation. PMID:24065106
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Bone Marrow Oxytocin Mediates the Anabolic Action of Estrogen on the Skeleton*
Colaianni, Graziana; Sun, Li; Di Benedetto, Adriana; Tamma, Roberto; Zhu, Ling-Ling; Cao, Jay; Grano, Maria; Yuen, Tony; Colucci, Sylvia; Cuscito, Concetta; Mancini, Lucia; Li, Jianhua; Nishimori, Katsuhiko; Bab, Itai; Lee, Heon-Jin; Iqbal, Jameel; Young, W. Scott; Rosen, Clifford; Zallone, Alberta; Zaidi, Mone
2012-01-01
Estrogen uses two mechanisms to exert its effect on the skeleton: it inhibits bone resorption by osteoclasts and, at higher doses, can stimulate bone formation. Although the antiresorptive action of estrogen arises from the inhibition of the MAPK JNK, the mechanism of its effect on the osteoblast remains unclear. Here, we report that the anabolic action of estrogen in mice occurs, at least in part, through oxytocin (OT) produced by osteoblasts in bone marrow. We show that the absence of OT receptors (OTRs) in OTR−/− osteoblasts or attenuation of OTR expression in silenced cells inhibits estrogen-induced osteoblast differentiation, transcription factor up-regulation, and/or OT production in vitro. In vivo, OTR−/− mice, known to have a bone formation defect, fail to display increases in trabecular bone volume, cortical thickness, and bone formation in response to estrogen. Furthermore, osteoblast-specific Col2.3-Cre+/OTRfl/fl mice, but not TRAP-Cre+/OTRfl/fl mice, mimic the OTR−/− phenotype and also fail to respond to estrogen. These data attribute the phenotype of OTR deficiency to an osteoblastic rather than an osteoclastic defect. Physiologically, feed-forward OT release in bone marrow by a rising estrogen concentration may facilitate rapid skeletal recovery during the latter phases of lactation. PMID:22761429
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R-Spondin 1 promotes vibration-induced bone formation in mouse models of osteoporosis
Wang, Haitao; Brennan, Tracy A.; Russell, Elizabeth; Kim, Jung-Hoon; Egan, Kevin P.; Chen, Qijun; Israelite, Craig; Schultz, David C.; Johnson, Frederick B.; Pignolo, Robert J.
2013-01-01
Bone tissue adapts to its functional environment by optimizing its morphology for mechanical demand. Among the mechanosensitive cells that recognize and respond to forces in the skeleton are osteocytes, osteoblasts, and mesenchymal progenitor cells (MPCs). Therefore, the ability to use mechanical signals to improve bone health through exercise and devices that deliver mechanical signals is an attractive approach to age-related bone loss; however, the extracellular or circulating mediators of such signals are largely unknown. Using SDS-PAGE separation of proteins secreted by MPCs in response to low magnitude mechanical signals and in-gel trypsin digestion followed by HPLC and mass spectroscopy, we identified secreted proteins up-regulated by vibratory stimulation. We exploited a cell senescence-associated secretory phenotype screen, and reasoned that a subset of vibration-induced proteins with diminished secretion by senescent MPCs will have the capacity to promote bone formation in vivo. We identified one such vibration-induced bone-enhancing (vibe) gene as R-Spondin 1, a Wnt pathway modulator, and demonstrated that it has the capacity to promote bone formation in three mouse models of age-related bone loss. By virtue of their secretory status, some vibe proteins may be candidates for pre-clinical development as anabolic agents for the treatment of osteoporosis. PMID:23974989
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Hypoxia inhibits the growth, differentiation and bone-forming capacity of rat osteoblasts
DOE Office of Scientific and Technical Information (OSTI.GOV)
Utting, J.C.; Robins, S.P.; Brandao-Burch, A.
2006-06-10
We investigated the effect of hypoxia on rat osteoblast function in long-term primary cultures. Reduction of pO{sub 2} from 20% to 5% and 2% decreased formation of mineralized bone nodules 1.7-fold and 11-fold, respectively. When pO{sub 2} was reduced further to 0.2%, bone nodule formation was almost abolished. The inhibitory effect of hypoxia on bone formation was partly due to decreased osteoblast proliferation, as measured by {sup 3}H-thymidine incorporation. Hypoxia also sharply reduced osteoblast alkaline phosphatase (ALP) activity and expression of mRNAs for ALP and osteocalcin, suggesting inhibition of differentiation to the osteogenic phenotype. Hypoxia did not increase the apoptosismore » of osteoblasts but induced a reversible state of quiescence. Transmission electron microscopy revealed that collagen fibrils deposited by osteoblasts cultured in 2% O{sub 2} were less organized and much less abundant than in 20% O{sub 2} cultures. Furthermore, collagen produced by hypoxic osteoblasts contained a lower percentage of hydroxylysine residues and exhibited an increased sensitivity to pepsin degradation. These data demonstrate the absolute oxygen requirement of osteoblasts for successful bone formation and emphasize the importance of the vasculature in maintaining bone health. We recently showed that hypoxia also acts in a reciprocal manner as a powerful stimulator of osteoclast formation. Considered together, our results help to explain the bone loss that occurs at the sites of fracture, tumors, inflammation and infection, and in individuals with vascular disease or anemia.« less
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Chen, Guangnan; Fang, Tingting; Qi, Yiying; Yin, Xiaofan; Di, Tuoyu; Feng, Gang; Lei, Zhong; Zhang, Yuxiang; Huang, Zhongming
2016-10-01
Bone nonunion treatments pose a challenge in orthopedics. This study investigated the joint effects of using mesenchymal stem cell (MSC) sheets with local injection of stromal cell-derived factor-1 (SDF-1) on bone formation. In vitro, we found that migration of MSCs was mediated by SDF-1 in a dose-dependent manner. Moreover, stimulation with SDF-1 had no direct effect on the proliferation or osteogenic differentiation of MSCs. Furthermore, the results indicated elevated expression levels of bone morphogenetic protein 2, alkaline phosphatase, osteocalcin, and vascular endothelial growth factor in MSC sheets compared with MSCs cultured in medium. New bone formation in fractures was evaluated by X-ray, micro-computed tomography (micro-CT), hematoxylin and eosin (H&E) staining, Safranin-O staining, and immunohistochemistry in vivo. In the rat bone fracture model, the MSC sheets transplanted into the injured site along with injection of SDF-1 showed significantly more new bone formation within the gap. Moreover, at 8 weeks, complete bone union was obtained in this group. In contrast, the control group showed nonunion of the bone. Our study suggests a new strategy involving the use of MSC sheets with a local injection of SDF-1 for hard tissue reconstruction, such as the healing of nonunions and bone defects.
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Kacena, Melissa A; Gundberg, Caren M; Horowitz, Mark C
2006-11-01
A growing body of evidence suggests that megakaryocytes (MK) or their growth factors play a role in skeletal homeostasis. MK have been shown to express and/or secrete several bone-related proteins including osteocalcin, osteonectin, bone sialoprotein, osteopontin, bone morphogenetic proteins, and osteoprotegerin. In addition, at least 3 mouse models have been described in which MK number was significantly elevated with an accompanying marked increase in bone mineral density. Mice overexpressing thrombopoietin, the major MK growth factor, have an osteosclerotic bone phenotype. Mice deficient in transcription factors GATA-1 and NF-E2, which are required for the differentiation of MK, exhibited a strikingly increased bone mass. Importantly, recent studies have demonstrated that MK can stimulate osteoblast (OB) proliferation and differentiation in vitro and that they can also inhibit osteoclast (OC) formation in vitro. These findings suggest that MK play a dual role in skeletal homeostasis by stimulating formation while simultaneously inhibiting resorption. Conversely, cells of the osteoblast lineage support hematopoiesis, including megakaryopoiesis. Postnatal hematopoiesis occurs almost solely in the bone marrow (BM), close to or on endosteal surfaces. This finding, in conjunction with the observed contact of OB with hematopoietic cells, has lead investigators to explore the molecular and cellular interactions between hematopoietic cells and cells of the OB lineage. Importantly, it has been shown that many of the cytokines that are critical for normal hematopoiesis and megakaryopoiesis are produced by OB. Indeed, culturing osteoblasts with CD34+ BM cells significantly enhances hematopoietic cell number by both enhancing the proliferation of long-term culture initiating cells and the proliferation and differentiation of MK. These data are consistent with cells in the OB lineage playing a critical role in the hematopoietic niche. Overall, these observations demonstrate the importance of MK-bone cell interactions in both skeletal homeostasis and hematopoiesis.
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Fumoto, Toshio; Ishii, Kiyo-Aki; Ito, Masako; Berger, Stefan; Schütz, Günther; Ikeda, Kyoji
2014-05-09
Although the mineralocorticoid receptor (MR) is expressed in osteoblasts and osteocytes and frequently co-localizes with the glucocorticoid receptors (GR), its pathophysiological functions in bone remain elusive. We report here that pharmacologic inhibition of MR function with eplerenone resulted in increased bone mass, with stimulation of bone formation and suppression of resorption, while specific genetic deletion of MR in osteoblast lineage cells had no effect. Further, treatment with eplerenone as well as specific deletion of MR in osteocytes ameliorated the cortical bone thinning caused by slow-release prednisolone pellets. Thus, MR may be involved in the deleterious effects of glucocorticoid excess on cortical bone. Copyright © 2014 Elsevier Inc. All rights reserved.
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Murakami, S; Takayama, S; Kitamura, M; Shimabukuro, Y; Yanagi, K; Ikezawa, K; Saho, T; Nozaki, T; Okada, H
2003-02-01
Several growth factors (or cytokines) have been recently investigated for their use as potential therapeutics for periodontal tissue regeneration. The objective of this study was to evaluate periodontal tissue regeneration, including new bone and cementum formation, following topical application of recombinant basic fibroblast growth factor (bFGF, FGF-2) to furcation class II defects. Twelve furcation class II bone defects were surgically created in six beagle dogs, then recombinant bFGF (30 micro g/site) + gelatinous carrier was topically applied to the bony defects. Six weeks after application, periodontal regeneration was analyzed. In all sites where bFGF was applied, periodontal ligament formation with new cementum deposits and new bone formation was observed histomorphometrically, in amounts greater than in the control sites. Basic FGF-applied sites exhibited significant regeneration as represented by the new bone formation rate (NBR) (83.6 +/- 14.3%), new trabecular bone formation rate (NTBR) (44.1 +/- 9.5%), and new cementum formation rate (NCR) (97.0 +/- 7.5%). In contrast, in the carrier-only sites, the NBR, NTBR, and NCR were 35.4 +/- 8.9%, 16.6 +/- 6.2%, and 37.2 +/- 15.1%, respectively. Moreover, no instances of epithelial down growth, ankylosis, or root resorption were observed in the bFGF-applied sites examined. The present results indicate that topical application of bFGF can enhance considerable periodontal regeneration in artificially created furcation class II bone defects of beagle dogs.
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Biomimetic coatings for bone tissue engineering of critical-sized defects.
Liu, Yuelian; Wu, Gang; de Groot, Klaas
2010-10-06
The repair of critical-sized bone defects is still challenging in the fields of implantology, maxillofacial surgery and orthopaedics. Current therapies such as autografts and allografts are associated with various limitations. Cytokine-based bone tissue engineering has been attracting increasing attention. Bone-inducing agents have been locally injected to stimulate the native bone-formation activity, but without much success. The reason is that these drugs must be delivered slowly and at a low concentration to be effective. This then mimics the natural method of cytokine release. For this purpose, a suitable vehicle was developed, the so-called biomimetic coating, which can be deposited on metal implants as well as on biomaterials. Materials that are currently used to fill bony defects cannot by themselves trigger bone formation. Therefore, biological functionalization of such materials by the biomimetic method resulted in a novel biomimetic coating onto different biomaterials. Bone morphogenetic protein 2 (BMP-2)-incorporated biomimetic coating can be a solution for a large bone defect repair in the fields of dental implantology, maxillofacial surgery and orthopaedics. Here, we review the performance of the biomimetic coating both in vitro and in vivo.
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An experimental study on the application of radionuclide imaging in repair of the bone defect
Zhu, Weimin; Wang, Daping; Zhang, Xiaojun; Lu, Wei; Liu, Jianquan; Peng, Liangquan; Li, Hao; Han, Yun; Zeng, Yanjun
2011-01-01
The aim of our study was to validate the effect of radionuclide imaging in early monitoring of the bone’s reconstruction, the animal model of bone defect was made on the rabbits repaired with HA artificial bone. The ability of bone defect repair was evaluated by using radionuclide bone imaging at 2, 4, 8 and 12 weeks postoperatively. The results indicate that the experimental group stimulated more bone formation than that of the control group. The differences of the bone reconstruction ability were statistically significant (p<0.05). The nano-HA artificial has good bone conduction, and it can be used for the treatment of bone defects. Radionuclide imaging may be an effective and first choice method for the early monitoring of the bone’s reconstruction. PMID:21875418
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Collier, M A; Brighton, C T; Norrdin, R; Twardock, A R; Rendano, V T
1985-03-01
The effect of a 20-microA direct-current implantable bone growth stimulator (BGS) on bone production with a "gap healing" model in the horse was evaluated. The right and left 4th metatarsal bones (Mt-4) were used in 7 adult horses to create the "gap healing" model. A 4-mm section of the Mt-4 bone was resected bilaterally in each horse. The BGS was surgically placed into the 7 left Mt-4 defects. The 7 right Mt-4 defects served as controls. Six horses survived the 16-week experimental period. Signs of pain, decreased range of limb motion, or lameness was not observed in any animal during the 16 weeks. None of the animals showed complete healing radiographically. Four stimulated sites showed less periosteal reaction and 2 showed greater reaction than the 6 controls. The greatest amount of periosteal reaction or bone resorption was seen around the screws and plates in both groups. Uptakes of 99mTc-MDP in counts/pixel for control sites and stimulated sites were 7.90 and 8.25 in the "gap defect" and 5.19 and 5.06 in the areas adjacent to the gap defect. The ratio of uptake between the gap defect and adjacent area was 1.5 and 1.58 respectively. Biocompatability of the BGS was excellent; however, 1 horse had a broken cathode wire 5 cm from the generator capsule at 6 weeks. All polyethylene cathode sheaths were fluid filled at 16 weeks. The average mineralization rates were 1.57 +/- 0.34, 1.71 +/- 0.28 mm/day and bone formation activity was 0.0182 +/- 0.171, and 0.0168 +/- 0.0149 mm2/day for control limbs and stimulated limbs, respectively. There was no significant difference between groups in any of the histomorphometric values measured. Direct current (20 microA) did not increase bone production in this experiment. Methods to objectively evaluate electrically induced osteogenesis and a "gap defect" model for BGS research on the horse are discussed. The results provide a basis for additional research on electrical stimulation of fractures in the horse and for dose-response studies.
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Long, Mian; Li, Shun-xiang; Xiao, Jiang-feng; Wang, Jian; Lozanoff, Scott; Zhang, Zhi-guang; Luft, Benjamin J; Johnson, Francis
2014-09-01
To study, at the cytological level, the basic concept of Chinese medicine that "the Kidney (Shen) controls the bone". Kaempferol was isolated form Rhizoma Drynariae (Gu Sui Bu, GSB) and at several concentrations was incubated with opossum kidney (OK) cells, osteoblasts (MC3T3 E1) and human fibroblasts (HF) at cell concentrations of 2×10(4)/mL. Opossum kidney cell-conditioned culture media with kaempferol at 70 nmol/L (70kaeOKM) and without kaempferol (0OKM) were used to stimulate MC3T3 E1 and HF proliferation. The bone morphological protein receptors I and II (BMPR I and II) in OK cells were identified by immune-fluorescence staining and Western blot analysis. Kaempferol was found to increase OK cell growth (P<0.05), but alone did not promote MC3T3 E1 or HF cell proliferation. However, although OKM by itself increased MC3T3 E1 growth by 198% (P<0.01), the 70kaeOKM further increased the growth of these cells by an additional 127% (P<0.01). It indicates that the kidney cell generates a previously unknown osteoblast growth factor (OGF) and kaempferol increases kidney cell secretion of OGF. Neither of these media had any significant effect on HF growth. Kaempferol also was found to increase the level of the BMPR II in OK cells. This lends strong support to the original idea that the Kidney has a significant influence over bone-formation, as suggested by some long-standing Chinese medical beliefs, kaempferol may also serve to stimulate kidney repair and indirectly stimulate bone formation.
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Khan, Kainat; Singh, Akanksha; Mittal, Monika; Sharan, Kunal; Singh, Nidhi; Dixit, Preety; Sanyal, Sabyasachi; Maurya, Rakesh; Chattopadhyay, Naibedya
2012-12-01
[6]-Gingerol, a major constituent of ginger, is considered to have several health beneficial effects. The effect of 6-gingerol on bone cells and skeleton of mice was investigated. The effects of 6-gingerol on mouse bone marrow macrophages and osteoblasts were studied. 6-Gingerol-stimulated osteoclast differentiation of bone marrow macrophages but had no effect on osteoblasts. Capsazepine, an inhibitor of TRPV1 (transient receptor potential vanilloid 1) channel, attenuated the pro-osteoclastogenic effect of 6-gingerol or capsaicin (an agonist of TRPV1). Similar to capsaicin, 6-gingerol stimulated Ca(2) + influx in osteoclasts. The effect of daily feeding of 6-gingerol for 5 wk on the skeleton of adult female Balb/cByJ mice was investigated. Mice treated with capsaicin and ovariectomized (OVx) mice served as controls for osteopenia. 6-Gingerol caused increase in trabecular osteoclast number, microarchitectural erosion at all trabecular sites and loss of vertebral stiffness, and these effects were comparable to capsaicin or OVx group. Osteoclast-specific serum and gene markers of 6-gingerol-treated mice were higher than the OVx group. Bone formation was unaffected by 6-gingerol. Daily feeding of 6-gingerol to skeletally mature female mice caused trabecular osteopenia, and the mechanism appeared to be activation of osteoclast formation via the TRPV1 channel. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Ho, Ming-Hua; Yao, Chih-Jung; Liao, Mei-Hsiu; Lin, Pei-I; Liu, Shing-Hwa; Chen, Ruei-Ming
2015-01-01
Osteoblasts play critical roles in bone formation. Our previous study showed that chitosan nanofibers can stimulate osteoblast proliferation and maturation. This translational study used an animal model of bone defects to evaluate the effects of chitosan nanofiber scaffolds on bone healing and the possible mechanisms. In this study, we produced uniform chitosan nanofibers with fiber diameters of approximately 200 nm. A bone defect was surgically created in the proximal femurs of male C57LB/6 mice, and then the left femur was implanted with chitosan nanofiber scaffolds for 21 days and compared with the right femur, which served as a control. Histological analyses revealed that implantation of chitosan nanofiber scaffolds did not lead to hepatotoxicity or nephrotoxicity. Instead, imaging analyses by X-ray transmission and microcomputed tomography showed that implantation of chitosan nanofiber scaffolds improved bone healing compared with the control group. In parallel, microcomputed tomography and bone histomorphometric assays further demonstrated augmentation of the production of new trabecular bone in the chitosan nanofiber-treated group. Furthermore, implantation of chitosan nanofiber scaffolds led to a significant increase in the trabecular bone thickness but a reduction in the trabecular parameter factor. As to the mechanisms, analysis by confocal microscopy showed that implantation of chitosan nanofiber scaffolds increased levels of Runt-related transcription factor 2 (Runx2), a key transcription factor that regulates osteogenesis, in the bone defect sites. Successively, amounts of alkaline phosphatase and osteocalcin, two typical biomarkers that can simulate bone maturation, were augmented following implantation of chitosan nanofiber scaffolds. Taken together, this translational study showed a beneficial effect of chitosan nanofiber scaffolds on bone healing through stimulating trabecular bone production due to upregulation of Runx2-mediated alkaline phosphatase and osteocalcin gene expressions. Our results suggest the potential of chitosan nanofiber scaffolds for therapy of bone diseases, including bone defects and bone fractures. PMID:26451104
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NASA Technical Reports Server (NTRS)
Martinez, D. A.; Orth, M. W.; Carr, K. E.; Vanderby, R. Jr; Vailas, A. C.
1996-01-01
The growth hormone (GH)-deficient dwarf rat was used to investigate recombinant human (rh) GH-induced bone formation and to determine whether rhGH facilitates simultaneous increases in bone formation and bone maturation during rapid growth. Twenty dwarf rats, 37 days of age, were randomly assigned to dwarf plus rhGH (GH; n = 10) and dwarf plus vehicle (n = 10) groups. The GH group received 1.25 mg rhGH/kg body wt two times daily for 14 days. Biochemical, morphological, and X-ray diffraction measurements were performed on the femur middiaphysis. rhGH stimulated new bone growth in the GH group, as demonstrated by significant increases (P < 0.05) in longitudinal bone length (6%), middiaphyseal cross-sectional area (20%), and the amount of newly accreted bone collagen (28%) in the total pool of middiaphyseal bone collagen. Cortical bone density, mean hydroxyapatite crystal size, and the calcium and collagen contents (microgram/mm3) were significantly smaller in the GH group (P < 0.05). Our findings suggest that the processes regulating new collagen accretion, bone collagen maturation, and mean hydroxyapatite crystal size may be independently regulated during rapid growth.
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Guenther, Catherine A; Wang, Zhen; Li, Emma; Tran, Misha C; Logan, Catriona Y; Nusse, Roel; Pantalena-Filho, Luiz; Yang, George P; Kingsley, David M
2015-08-01
Bone morphogenetic proteins (BMPs) are key signaling molecules required for normal development of bones and other tissues. Previous studies have shown that null mutations in the mouse Bmp5 gene alter the size, shape and number of multiple bone and cartilage structures during development. Bmp5 mutations also delay healing of rib fractures in adult mutants, suggesting that the same signals used to pattern embryonic bone and cartilage are also reused during skeletal regeneration and repair. Despite intense interest in BMPs as agents for stimulating bone formation in clinical applications, little is known about the regulatory elements that control developmental or injury-induced BMP expression. To compare the DNA sequences that activate gene expression during embryonic bone formation and following acute injuries in adult animals, we assayed regions surrounding the Bmp5 gene for their ability to stimulate lacZ reporter gene expression in transgenic mice. Multiple genomic fragments, distributed across the Bmp5 locus, collectively coordinate expression in discrete anatomic domains during normal development, including in embryonic ribs. In contrast, a distinct regulatory region activated expression following rib fracture in adult animals. The same injury control region triggered gene expression in mesenchymal cells following tibia fracture, in migrating keratinocytes following dorsal skin wounding, and in regenerating epithelial cells following lung injury. The Bmp5 gene thus contains an "injury response" control region that is distinct from embryonic enhancers, and that is activated by multiple types of injury in adult animals. Copyright © 2015 Elsevier Inc. All rights reserved.
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Pereira, M; Jeyabalan, J; Jørgensen, C S; Hopkinson, M; Al-Jazzar, A; Roux, J P; Chavassieux, P; Orriss, I R; Cleasby, M E; Chenu, C
2015-12-01
Some anti-diabetic therapies can have adverse effects on bone health and increase fracture risk. In this study, we tested the skeletal effects of chronic administration of two Glucagon-like peptide-1 receptor agonists (GLP-1RA), increasingly used for type 2 diabetes treatment, in a model of osteoporosis associated bone loss and examined the expression and activation of GLP-1R in bone cells. Mice were ovariectomised (OVX) to induce bone loss and four weeks later they were treated with Liraglutide (LIR) 0.3mg/kg/day, Exenatide (Ex-4) 10 μg/kg/day or saline for four weeks. Mice were injected with calcein and alizarin red prior to euthanasia, to label bone-mineralising surfaces. Tibial micro-architecture was determined by micro-CT and bone formation and resorption parameters measured by histomorphometric analysis. Serum was collected to measure calcitonin and sclerostin levels, inhibitors of bone resorption and formation, respectively. GLP-1R mRNA and protein expression were evaluated in the bone, bone marrow and bone cells using RT-PCR and immunohistochemistry. Primary osteoclasts and osteoblasts were cultured to evaluate the effect of GLP-1RA on bone resorption and formation in vitro. GLP-1RA significantly increased trabecular bone mass, connectivity and structure parameters but had no effect on cortical bone. There was no effect of GLP-1RA on bone formation in vivo but an increase in osteoclast number and osteoclast surfaces was observed with Ex-4. GLP-1R was expressed in bone marrow cells, primary osteoclasts and osteoblasts and in late osteocytic cell line. Both Ex-4 and LIR stimulated osteoclastic differentiation in vitro but slightly reduced the area resorbed per osteoclast. They had no effect on bone nodule formation in vitro. Serum calcitonin levels were increased and sclerostin levels decreased by Ex-4 but not by LIR. Thus, GLP-1RA can have beneficial effects on bone and the expression of GLP-1R in bone cells may imply that these effects are exerted directly on the tissue. Copyright © 2015 Elsevier Inc. All rights reserved.
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Influence of controlled immediate loading and implant design on peri-implant bone formation.
Vandamme, Katleen; Naert, Ignace; Geris, Liesbet; Vander Sloten, Jozef; Puers, Robert; Duyck, Joke
2007-02-01
Tissue formation at the implant interface is known to be sensitive to mechanical stimuli. The aim of the study was to compare the bone formation around immediately loaded versus unloaded implants in two different implant macro-designs. A repeated sampling bone chamber with a central implant was installed in the tibia of 10 rabbits. Highly controlled loading experiments were designed for a cylindrical (CL) and screw-shaped (SL) implant, while the unloaded screw-shaped (SU) implant served as a control. An F-statistic model with alpha=5% determined statistical significance. A significantly higher bone area fraction was observed for SL compared with SU (p<0.0001). The mineralized bone fraction was the highest for SL and significantly different from SU (p<0.0001). The chance that osteoid- and bone-to-implant contact occurred was the highest for SL and significantly different from SU (p<0.0001), but not from CL. When bone-to-implant contact was observed, a loading (SL versus SU: p=0.0049) as well as an implant geometry effect (SL versus CL: p=0.01) was found, in favour of the SL condition. Well-controlled immediate implant loading accelerates tissue mineralization at the interface. Adequate bone stimulation via mechanical coupling may account for the larger bone response around the screw-type implant compared with the cylindrical implant.
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Polycystin-1 interacts with TAZ to stimulate osteoblastogenesis and inhibit adipogenesis
Xiao, Zhousheng; Baudry, Jerome; Cao, Li; ...
2017-11-27
The molecular mechanisms that transduce the osteoblast response to physical forces in the bone microenvironment are poorly understood. In this paper, we used genetic and pharmacological experiments to determine whether the polycystins PC1 and PC2 (encoded by Pkd1 and Pkd2) and the transcriptional coactivator TAZ form a mechanosensing complex in osteoblasts. Compound-heterozygous mice lacking 1 copy of Pkd1 and Taz exhibited additive decrements in bone mass, impaired osteoblast-mediated bone formation, and enhanced bone marrow fat accumulation. Bone marrow stromal cells and osteoblasts derived from these mice showed impaired osteoblastogenesis and enhanced adipogenesis. Increased extracellular matrix stiffness and application of mechanicalmore » stretch to multipotent mesenchymal cells stimulated the nuclear translocation of the PC1 C-terminal tail/TAZ (PC1-CTT/TAZ) complex, leading to increased runt-related transcription factor 2–mediated (Runx2-mediated) osteogenic and decreased PPARγ-dependent adipogenic gene expression. Using structure-based virtual screening, we identified a compound predicted to bind to PC2 in the PC1:PC2 C-terminal tail region with helix:helix interaction. This molecule stimulated polycystin- and TAZ-dependent osteoblastogenesis and inhibited adipogenesis. Therefore, we show that polycystins and TAZ integrate at the molecular level to reciprocally regulate osteoblast and adipocyte differentiation, indicating that the polycystins/TAZ complex may be a potential therapeutic target to increase bone mass.« less
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Polycystin-1 interacts with TAZ to stimulate osteoblastogenesis and inhibit adipogenesis
DOE Office of Scientific and Technical Information (OSTI.GOV)
Xiao, Zhousheng; Baudry, Jerome; Cao, Li
The molecular mechanisms that transduce the osteoblast response to physical forces in the bone microenvironment are poorly understood. In this paper, we used genetic and pharmacological experiments to determine whether the polycystins PC1 and PC2 (encoded by Pkd1 and Pkd2) and the transcriptional coactivator TAZ form a mechanosensing complex in osteoblasts. Compound-heterozygous mice lacking 1 copy of Pkd1 and Taz exhibited additive decrements in bone mass, impaired osteoblast-mediated bone formation, and enhanced bone marrow fat accumulation. Bone marrow stromal cells and osteoblasts derived from these mice showed impaired osteoblastogenesis and enhanced adipogenesis. Increased extracellular matrix stiffness and application of mechanicalmore » stretch to multipotent mesenchymal cells stimulated the nuclear translocation of the PC1 C-terminal tail/TAZ (PC1-CTT/TAZ) complex, leading to increased runt-related transcription factor 2–mediated (Runx2-mediated) osteogenic and decreased PPARγ-dependent adipogenic gene expression. Using structure-based virtual screening, we identified a compound predicted to bind to PC2 in the PC1:PC2 C-terminal tail region with helix:helix interaction. This molecule stimulated polycystin- and TAZ-dependent osteoblastogenesis and inhibited adipogenesis. Therefore, we show that polycystins and TAZ integrate at the molecular level to reciprocally regulate osteoblast and adipocyte differentiation, indicating that the polycystins/TAZ complex may be a potential therapeutic target to increase bone mass.« less
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Simulation of bone resorption-repair coupling in vitro.
Jones, S J; Gray, C; Boyde, A
1994-10-01
In the normal adult human skeleton, new bone formation by osteoblasts restores the contours of bone surfaces following osteoclastic bone resorption, but the evidence for resorption-repair coupling remains circumstantial. To investigate whether sites of prior resorption, more than the surrounding unresorbed surface, attract osteoblasts or stimulate them to proliferate or make new matrix, we developed a simple in vitro system in which resorption-repair coupling occurs. Resorption pits were produced in mammalian dentine or bone slabs by culturing chick bone-derived cells on them for 2-3 days. The chick cells were swept off and the substrata reseeded with rat calvarial osteoblastic cells, which make bone nodules in vitro, for periods of up to 8 weeks. Cell positions and new bone formation were investigated by ordinary light microscopy, fluorescence and reflection confocal laser microscopy, and SEM, in stained and unstained samples. There was no evidence that the osteoblasts were especially attracted to, or influenced by, the sites of resorption in dentine or bone before cell confluence was reached. Bone formation was identified by light microscopy by the accumulation of matrix, staining with alizarin and calcein and by von Kossa's method, and confirmed by scanning electron microscopy (SEM) by using backscattered electron (BSE) and transmitted electron imaging of unembedded samples and BSE imaging of micro-milled embedded material. These new bone patches were located initially in the resorption pits. The model in vitro system may throw new light on the factors that control resorption-repair coupling in the mineralised tissues in vivo.
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Engineered decellularized matrices to instruct bone regeneration processes.
Papadimitropoulos, Adam; Scotti, Celeste; Bourgine, Paul; Scherberich, Arnaud; Martin, Ivan
2015-01-01
Despite the significant progress in the field of bone tissue engineering, cell-based products have not yet reached the stage of clinical adoption. This is due to the uncertain advantages from the standard-of-care, combined with challenging cost-and regulatory-related issues. Novel therapeutic approaches could be based on exploitation of the intrinsic regenerative capacity of bone tissue, provided the development of a deeper understanding of its healing mechanisms. While it is well-established that endogenous progenitors can be activated toward bone formation by overdoses of single morphogens, the challenge to stimulate the healing processes by coordinated and controlled stimulation of specific cell populations remains open. Here, we review the recent approaches to generate osteoinductive materials based on the use of decellularized extracellular matrices (ECM) as reservoirs of multiple factors presented at physiological doses and through the appropriate ligands. We then propose the generation of customized engineered and decellularized ECM (i) as a tool to better understand the processes of bone regeneration and (ii) as safe and effective "off-the-shelf" bone grafts for clinical use. This article is part of a Special Issue entitled Stem Cells and Bone. Copyright © 2014 Elsevier Inc. All rights reserved.
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Schumacher, M; Lode, A; Helth, A; Gelinsky, M
2013-12-01
In the present study, the in vitro effects of novel strontium-modified calcium phosphate bone cements (SrCPCs), prepared using two different approaches on human-bone-marrow-derived mesenchymal stem cells (hMSCs), were evaluated. Strontium ions, known to stimulate bone formation and therefore already used in systemic osteoporosis therapy, were incorporated into a hydroxyapatite-forming calcium phosphate bone cement via two simple approaches: incorporation of strontium carbonate crystals and substitution of Ca(2+) by Sr(2+) ions during cement setting. All modified cements released 0.03-0.07 mM Sr(2+) under in vitro conditions, concentrations that were shown not to impair the proliferation or osteogenic differentiation of hMSCs. Furthermore, strontium modification led to a reduced medium acidification and Ca(2+) depletion in comparison to the standard calcium phosphate cement. In indirect and direct cell culture experiments with the novel SrCPCs significantly enhanced cell proliferation and differentiation were observed. In conclusion, the SrCPCs described here could be beneficial for the local treatment of defects, especially in the osteoporotic bone. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
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Evidence that Resorption of Bone by Rat Peritoneal Macrophages Occurs in an Acidic Environment
NASA Technical Reports Server (NTRS)
Blair, H. C.
1985-01-01
Skeletal loss in space, like any form of osteoporosis, reflects a relative imbalance of the activities of cells resorbing (degrading) or forming bone. Consequently, prevention of weightlessness induced bone loss may theoretically be accomplished by (1) stimulating bone formation or (2) inhibiting bone resorption. This approach, however, requires fundamental understanding of the mechanisms by which cells form or degrade bone, information not yet at hand. An issue central to bone resorption is the pH at which resorption takes place. The pH dependent spectral shift of a fluorescent dye (fluorescein isothiocyanate) conjugated to bone matrix was used to determine the pH at the resorptive cell bone matrix interface. Devitalized rat bone was used as the substrate, and rat peritoneal macrophages were used as the bone resorbing cells. The results suggest that bone resorption is the result of generation of an acidic microenvironment at the cell matrix junction.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Kimura, Hiroaki; Akiyama, Haruhiko; Nakamura, Takashi
We identified a cDNA encoding mouse Tenascin-W (TN-W) upregulated by bone morphogenetic protein (Bmp)2 in ATDC5 osteo-chondroprogenitors. In adult mice, TN-W was markedly expressed in bone. In mouse embryos, during endochondral bone formation TN-W was localized in perichondrium/periosteum, but not in trabecular and cortical bones. During bone fracture repair, cells in the newly formed perichondrium/periosteum surrounding the cartilaginous callus expressed TN-W. Furthermore, TN-W was detectable in perichondrium/periosteum of Runx2-null and Osterix-null embryos, indicating that TN-W is expressed in preosteoblasts. In CFU-F and -O cells, TN-W had no effect on initiation of osteogenesis of bone marrow cells, and in MC3T3-E1 osteoblasticmore » cells TN-W inhibited cell proliferation and Col1a1 expression. In addition, TN-W suppressed canonical Wnt signaling which stimulates osteoblastic differentiation. Our results indicate that TN-W is a novel marker of preosteoblasts in early stage of osteogenesis, and that TN-W inhibits cell proliferation and differentiation of preosteoblasts mediated by canonical Wnt signaling.« less
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Maruyama, Kenta; Kawagoe, Tatsukata; Kondo, Takeshi; Akira, Shizuo; Takeuchi, Osamu
2012-08-17
The differentiation of bone-resorbing osteoclasts is induced by RANKL signaling, and leads to the activation of NF-κB via TRAF6 activation. TRAF family member-associated NF-κB activator (TANK) acts as a negative regulator of Toll-like receptors (TLRs) and B-cell receptor (BCR) signaling by inhibiting TRAF6 activation. Tank(-/-) mice spontaneously develop autoimmune glomerular nephritis in an IL-6-dependent manner. Despite its importance in the TCRs and BCR-activated TRAF6 inhibition, the involvement of TANK in RANKL signaling is poorly understood. Here, we report that TANK is a negative regulator of osteoclast differentiation. The expression levels of TANK mRNA and protein were up-regulated during RANKL-induced osteoclastogenesis, and overexpression of TANK in vitro led to a decrease in osteoclast formation. The in vitro osteoclastogenesis of Tank(-/-) cells was significantly increased, accompanied by increased ubiquitination of TRAF6 and enhanced canonical NF-κB activation in response to RANKL stimulation. Tank(-/-) mice showed severe trabecular bone loss, but increased cortical bone mineral density, because of enhanced bone erosion and formation. TANK mRNA expression was induced during osteoblast differentiation and Tank(-/-) osteoblasts exhibited enhaced NF-κB activation, IL-11 expression, and bone nodule formation than wild-type control cells. Finally, wild-type mice transplanted with bone marrow cells from Tank(-/-) mice showed trabecular bone loss analogous to that in Tank(-/-) mice. These findings demonstrate that TANK is critical for osteoclastogenesis by regulating NF-κB, and is also important for proper bone remodeling.
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Maruyama, Kenta; Kawagoe, Tatsukata; Kondo, Takeshi; Akira, Shizuo; Takeuchi, Osamu
2012-01-01
The differentiation of bone-resorbing osteoclasts is induced by RANKL signaling, and leads to the activation of NF-κB via TRAF6 activation. TRAF family member-associated NF-κB activator (TANK) acts as a negative regulator of Toll-like receptors (TLRs) and B-cell receptor (BCR) signaling by inhibiting TRAF6 activation. Tank−/− mice spontaneously develop autoimmune glomerular nephritis in an IL-6-dependent manner. Despite its importance in the TCRs and BCR-activated TRAF6 inhibition, the involvement of TANK in RANKL signaling is poorly understood. Here, we report that TANK is a negative regulator of osteoclast differentiation. The expression levels of TANK mRNA and protein were up-regulated during RANKL-induced osteoclastogenesis, and overexpression of TANK in vitro led to a decrease in osteoclast formation. The in vitro osteoclastogenesis of Tank−/− cells was significantly increased, accompanied by increased ubiquitination of TRAF6 and enhanced canonical NF-κB activation in response to RANKL stimulation. Tank−/− mice showed severe trabecular bone loss, but increased cortical bone mineral density, because of enhanced bone erosion and formation. TANK mRNA expression was induced during osteoblast differentiation and Tank−/− osteoblasts exhibited enhaced NF-κB activation, IL-11 expression, and bone nodule formation than wild-type control cells. Finally, wild-type mice transplanted with bone marrow cells from Tank−/− mice showed trabecular bone loss analogous to that in Tank−/− mice. These findings demonstrate that TANK is critical for osteoclastogenesis by regulating NF-κB, and is also important for proper bone remodeling. PMID:22773835
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2013-04-29
transduction of human mesenchymal stem cells (MSCs), BMP2 was not detectable by Western blotting, whereas high levels of the protein were produced by A549 (human... mesenchymal stem cells , generating high levels of BMP2. When Ad5BMP2 or Ad5F35BMP2 were compared in vitro for their ability to induce BMP2 synthesis...in human mesenchymal stem cells and in vivo for their ability to stimulate formation of heterotopic bone, mineralized bone was radiologically
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Osteoinductive effect of bone bank allografts on human osteoblasts in culture.
de la Piedra, Concepción; Vicario, Carlos; de Acuña, Lucrecia Rodríguez; García-Moreno, Carmen; Traba, Maria Luisa; Arlandis, Santiago; Marco, Fernando; López-Durán, Luis
2008-02-01
Incorporation of a human bone allograft requires osteoclast activity and growth of recipient osteoblasts. The aim of this work was to study the effects produced by autoclavated and -80 degrees C frozen bone allografts on osteoblast proliferation and synthesis of interleukin 6 (IL6), activator of bone resorption, aminoterminal propeptide of procollagen I (PINP), marker of bone matrix formation, and osteoprotegerin (OPG), inhibitor of osteoclast activity and differentiation. Allografts were obtained from human femoral heads. Human osteoblasts were cultured in the presence (problem group) or in the absence (control group) of allografts during 15 days. Allografts produced a decrease in osteoblast proliferation in the first week of the experiment, and an increase in IL6 mRNA, both at 3 h and 2 days, and an increase in the IL6 released to the culture medium the second day of the experiment. We found a decrease in OPG released to the culture on the 2nd and fourth days. These results suggest an increase in bone resorption and a decrease in bone formation in the first week of the experiment. In the second week, allografts produced an increase in osteoblast proliferation and PINP release to the culture medium, indicating an increase in bone formation; an increase in OPG released to the culture medium, which would indicate a decrease in bone resorption; and a decrease in IL6, indicating a decrease in bone resorption stimulation. These results demonstrate that autoclavated and -80 degrees C frozen bone allografts produce in bone environment changes that regulate their own incorporation to the recipient bone.
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Effects of epidermal growth factor on bone formation and resorption in vivo
DOE Office of Scientific and Technical Information (OSTI.GOV)
Marie, P.J.; Hott, M.; Perheentupa, J.
1990-02-01
The effects of mouse epidermal growth factor (EGF) on bone formation and resorption were examined in male mice. EGF administration (2-200 ng.g-1.day-1 ip for 7 days) induced a dose-dependent rise in plasma EGF levels that remained within physiological range. Histomorphometric analysis of caudal vertebrae showed that EGF (20 and 200 ng.g-1.day-1) reduced the endosteal matrix and mineral appositional rates after 5 days of treatment as measured by double (3H)proline labeling and double tetracycline labeling, respectively. This effect was transitory and was not observed after 7 days of EGF administration. EGF administered for 7 days induced a dose-dependent increase in themore » periosteal osteoblastic and tetracycline double-labeled surfaces. At high dosage (200 ng.g-1.day-1) EGF administration increased the osteoclastic surface and the number of acid phosphatase-stained osteoclasts, although plasma calcium remained normal. The results show that EGF administration at physiological doses induces distinct effects on endosteal and periosteal bone formation and that the effects are dependent on EGF dosage and duration of treatment. This study indicates that EGF at physiological dosage stimulates periosteal bone formation and increases endosteal bone resorption in the growing mouse.« less
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Findeisen, Hannes M; Gizard, Florence; Zhao, Yue; Cohn, Dianne; Heywood, Elizabeth B; Jones, Karrie L; Lovett, David H; Howatt, Deborah A; Daugherty, Alan; Bruemmer, Dennis
2011-02-01
Abdominal aortic aneurysms (AAA) are an age-related vascular disease and an important cause of morbidity and mortality. In this study, we sought to determine whether the catalytic component of telomerase, telomerase reverse transcriptase (TERT), modulates angiotensin (Ang) II-induced AAA formation. Low-density lipoprotein receptor-deficient (LDLr-/-) mice were lethally irradiated and reconstituted with bone marrow-derived cells from TERT-deficient (TERT-/-) mice or littermate wild-type mice. Mice were placed on a diet enriched in cholesterol, and AAA formation was quantified after 4 weeks of Ang II infusion. Repopulation of LDLr-/- mice with TERT-/- bone marrow-derived cells attenuated Ang II-induced AAA formation. TERT-deficient recipient mice revealed modest telomere attrition in circulating leukocytes at the study end point without any overt effect of the donor genotype on white blood cell counts. In mice repopulated with TERT-/- bone marrow, aortic matrix metalloproteinase-2 (MMP-2) activity was reduced, and TERT-/- macrophages exhibited decreased expression and activity of MMP-2 in response to stimulation with Ang II. Finally, we demonstrated in transient transfection studies that TERT overexpression activates the MMP-2 promoter in macrophages. TERT deficiency in bone marrow-derived macrophages attenuates Ang II-induced AAA formation in LDLr-/- mice and decreases MMP-2 expression. These results point to a previously unrecognized role of TERT in the pathogenesis of AAA.
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A novel role for cathepsin K in periosteal osteoclast precursors during fracture repair.
Walia, Bhavita; Lingenheld, Elizabeth; Duong, Le; Sanjay, Archana; Drissi, Hicham
2018-03-01
Osteoporosis management is currently centered around bisphosphonates, which inhibit osteoclast (OC) bone resorption but do not affect bone formation. This reduces fracture risk, but fails to restore healthy bone remodeling. Studies in animal models showed that cathepsin K (CatK) inhibition by genetic deletion or chemical inhibitors maintained bone formation while abrogating resorption during bone remodeling and stimulated periosteal bone modeling. Recently, periosteal mononuclear tartrate-resistant acid phosphatase-positive (TRAP + ) osteoclast precursors (OCPs) were shown to augment angiogenesis-coupled osteogenesis. CatK gene deletion increased osteoblast differentiation via enhanced OCP and OC secretion of platelet-derived growth factor (PDGF)-BB and sphingosine 1 phosphate. The effects of periosteum-derived OCPs on bone remodeling are unknown, particularly with regard to fracture repair. We hypothesized that periosteal OCPs derived from CatK-null (Ctsk -/- ) mice may enhance periosteal bone formation during fracture repair. We found fewer periosteal OCPs in Ctsk -/- mice under homeostatic conditions; however, after fracture, this population increased in number relative to that seen in wild-type (WT) mice. Enhanced TRAP staining and greater expression of PDGF-BB were observed in fractured Ctsk -/- femurs relative to WT femurs. This early pattern of augmented PDGF-BB expression in Ctsk -/- mice may contribute to improved fracture healing by enhancing callus mineralization in Ctsk -/- mice. © 2018 New York Academy of Sciences.
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Butyric acid stimulates bone sialoprotein gene transcription.
Yang, Li; Li, Zhengyang; Li, Xinyue; Wang, Zhitao; Wang, Shuang; Sasaki, Yoko; Takai, Hideki; Ogata, Yorimasa
2010-06-01
Butyric acid (sodium butyrate; BA) is an extracellular metabolite secreted from periodontopathic bacteria present in subgingival plaque. BA induces apoptosis of T and B cells, and acts as a potent inhibitor of histone deacetylases. Bone sialoprotein (BSP) is thought to function in the initial mineralization of bone, and may be crucial for osteoblast differentiation, bone matrix mineralization and tumor metastasis. In the present study we investigated the regulation of BSP transcription by BA in rat osteoblast-like ROS17/2.8 cells. At 12 h, BA (10(-4) M) increased the level of BSP mRNA, and enhanced the luciferase activity of the construct pLUC3, which includes the promoter sequence between nucleotides -116 and +60. Transcriptional stimulation by BA was abrogated in the pLUC3 construct which containing a 2-bp mutation in the fibroblast growth factor 2 response element (FRE). Gel shift analyses showed that BA increased the binding of nuclear protein to FRE. These data suggest that BA increases the transcription of the BSP gene mediated through FRE in the rat BSP gene promoter, and induces osteoblast activity in the early stage of bone formation.
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Progesterone as a bone-trophic hormone.
Prior, J C
1990-05-01
Experimental, epidemiological, and clinical data indicate that progesterone is active in bone metabolism. Progesterone appears to act directly on bone by engaging an osteoblast receptor or indirectly through competition for a glucocorticoid osteoblast receptor. Progesterone seems to promote bone formation and/or increase bone turnover. It is possible, through estrogen-stimulated increased progesterone binding to the osteoblast receptor, that progesterone plays a role in the coupling of bone resorption with bone formation. A model of the interdependent actions of progesterone and estrogen on appropriately-"ready" cells in each bone multicellular unit can be tied into the integrated secretions of these hormones within the ovulatory cycle. Figure 5 is an illustration of this concept. It shows the phases of the bone remodeling cycle in parallel with temporal changes in gonadal steroids across a stylized ovulatory cycle. Increasing estrogen production before ovulation may reverse the resorption occurring in a "sensitive" bone multicellular unit while gonadal steroid levels are low at the time of menstrual flow. The bone remodeling unit would then be ready to begin a phase of formation as progesterone levels peaked in the midluteal phase. From this perspective, the normal ovulatory cycle looks like a natural bone-activating, coherence cycle. Critical analysis of the reviewed data indicate that progesterone meets the necessary criteria to play a causal role in mineral metabolism. This review provides the preliminary basis for further molecular, genetic, experimental, and clinical investigation of the role(s) of progesterone in bone remodeling. Much further data are needed about the interrelationships between gonadal steroids and the "life cycle" of bone. Feldman et al., however, may have been prophetic when he commented; "If this anti-glucocorticoid effect of progesterone also holds true in bone, then postmenopausal osteoporosis may be, in part, a progesterone deficiency disease."
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Siclari, Valerie A.; Zhu, Ji; Akiyama, Kentaro; Liu, Fei; Zhang, Xianrong; Chandra, Abhishek; Nah-Cederquist, Hyun-Duck; Shi, Songtao; Qin, Ling
2013-01-01
Long bone is an anatomically complicated tissue with trabecular-rich metaphyses at two ends and cortical-rich diaphysis at the center. The traditional flushing method only isolates mesenchymal progenitor cells from the central region of long bones and these cells are distant from the bone surface. We propose that mesenchymal progenitors residing in endosteal bone marrow that is close to the sites of bone formation, such as trabecular bone and endosteum, behave differently from those in the central bone marrow. In this report, we separately isolated endosteal bone marrow using a unique enzymatic digestion approach and demonstrated that it contained a much higher frequency of mesenchymal progenitors than the central bone marrow. Endosteal mesenchymal progenitors express traditional mesenchymal stem cell markers and are capable of multi-lineage differentiation. However, we found that mesenchymal progenitors isolated from different anatomical regions of the marrow did exhibit important functional differences. Compared to their central marrow counterparts, endosteal mesenchymal progenitors have superior proliferative ability with reduced expression of cell cycle inhibitors. They showed greater immunosuppressive activity in culture and in a mouse model of inflammatory bowel disease. Aging is a major contributing factor for trabecular bone loss. We found that old mice have a dramatically decreased number of endosteal mesenchymal progenitors compared to young mice. Parathyroid hormone (PTH) treatment potently stimulates bone formation. A single PTH injection greatly increased the number of endosteal mesenchymal progenitors, particularly those located at the metaphyseal bone, but had no effect on their central counterparts. In summary, endosteal mesenchymal progenitors are more metabolically active and relevant to physiological bone formation than central mesenchymal progenitors. Hence, they represent a biologically important target for future mesenchymal stem cell studies. PMID:23274348
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A concise review of testosterone and bone health
Mohamad, Nur-Vaizura; Soelaiman, Ima-Nirwana; Chin, Kok-Yong
2016-01-01
Osteoporosis is a condition causing significant morbidity and mortality in the elderly population worldwide. Age-related testosterone deficiency is the most important factor of bone loss in elderly men. Androgen can influence bone health by binding to androgen receptors directly or to estrogen receptors (ERs) indirectly via aromatization to estrogen. This review summarized the direct and indirect effects of androgens on bone derived from in vitro, in vivo, and human studies. Cellular studies showed that androgen stimulated the proliferation of preosteoblasts and differentiation of osteoblasts. The converted estrogen suppressed osteoclast formation and resorption activity by blocking the receptor activator of nuclear factor k-B ligand pathway. In animal studies, activation of androgen and ERα, but not ERβ, was shown to be important in acquisition and maintenance of bone mass. Human epidemiological studies demonstrated a significant relationship between estrogen and testosterone in bone mineral density and fracture risk, but the relative significance between the two remained debatable. Human experimental studies showed that estrogen was needed in suppressing bone resorption, but both androgen and estrogen were indispensable for bone formation. As a conclusion, maintaining optimal level of androgen is essential in preventing osteoporosis and its complications in elderly men. PMID:27703340
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2012-01-01
Background Bone grafts from bone banks might be mixed with bisphosphonates to inhibit the osteoclastic response. This inhibition prevents the osteoclasts to resorb the allograft bone before new bone has been formed by the osteoblasts, which might prevent instability. Since bisphosphonates may not only inhibit osteoclasts, but also osteoblasts and thus bone formation, we studied different bisphosphonate concentrations combined with allograft bone. We investigated whether locally applied alendronate has an optimum dose with respect to bone resorption and formation. Further, we questioned whether the addition of demineralized bone matrix (DBM), would stimulate bone formation. Finally, we studied the effect of high levels of antibiotics on bone allograft healing, since mixing allograft bone with antibiotics might reduce the infection risk. Methods 25 goats received eight bone conduction chambers in the cortical bone of the proximal medial tibia. Five concentrations of alendronate (0, 0.5 mg/mL, 1 mg/mL, 2 mg/mL, and 10 mg/mL) were tested in combination with allograft bone and supplemented with cefazolin (200 μg/mL). Allograft not supplemented with alendronate and cefazolin served as control. In addition, allograft mixed with demineralized bone matrix, with and without alendronate, was tested. After 12 weeks, graft bone area and new bone area were determined with manual point counting. Results Graft resorption decreased significantly (p < 0.001) with increasing alendronate concentration. The area of new bone in the 1 mg/mL alendronate group was significantly (p = 0.002) higher when compared to the 10 mg/mL group. No differences could be observed between the group without alendronate, but with demineralized bone, and the control groups. Conclusions A dose-response relationship for local application of alendronate has been shown in this study. Most new bone was present at 1 mg/mL alendronate. Local application of cefazolin had no effect on bone remodelling. PMID:22443362
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Zhao, Ji-Jun; Wu, Zhao-Feng; Yu, Ying-Hao; Wang, Ling; Cheng, Li
2018-09-01
To explore the effects of IL-7/IL-7R on the RANKL-mediated osteoclast differentiation in vitro and OVX-induced bone loss in vivo. BMMs and RAW264.7 were transfected with IL-7, IL-7R siRNA, c-Fos siRNA, and c-jun siRNA and later stimulated by RANKL. TRAP and toluidine blue staining were used to observe osteoclast formation and bone resorption, respectively. HE and TRAP staining were used to detect trabecular bone microstructure and osteoclasts of mice, respectively. qRT-PCR and Western blot analysis were used to examine expression. IL-7 unregulated the expression of CTSK, NFATc1, MMP9, and the phosphorylation of p38 and Akt by activating the c-Fos/c-Jun pathway, which increased osteoclast numbers and bone resorption in RANKL-stimulated macrophages. While IL-7R siRNA and c-Fos siRNA decreased the expression, as well as and the phosphorylation of p38 and Akt.IL-7 decreased the BMD and OPG expression in OVX-induced mice and increased the TRAP positive cells, the mRNA expression of c-fos, c-jun, and RANKL, which was contradictory to IL-7R siRNA, and c-Fos siRNA. Furthermore, IL-7R siRNA and c-Fos siRNA caused thicker trabeculae, increased trabecular number, and decreased osteolysis in OVX mice. IL-7/IL-7R can promote RANKL-mediated osteoclast formation and bone resorption by activating the c-Fos/c-Jun pathway, as well as inducing bone loss in OVX mice. © 2018 Wiley Periodicals, Inc.
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Nanotechnology for Stimulating Osteoprogenitor Differentiation
Ibrahim, A.; Bulstrode, N.W.; Whitaker, I.S.; Eastwood, D.M.; Dunaway, D.; Ferretti, P.
2016-01-01
Background: Bone is the second most transplanted tissue and due to its complex structure, metabolic demands and various functions, current reconstructive options such as foreign body implants and autologous tissue transfer are limited in their ability to restore defects. Most tissue engineering approaches target osteoinduction of osteoprogenitor cells by modifying the extracellular environment, using scaffolds or targeting intracellular signaling mechanisms or commonly a combination of all of these. Whilst there is no consensus as to what is the optimal cell type or approach, nanotechnology has been proposed as a powerful tool to manipulate the biomolecular and physical environment to direct osteoprogenitor cells to induce bone formation. Methods: Review of the published literature was undertaken to provide an overview of the use of nanotechnology to control osteoprogenitor differentiation and discuss the most recent developments, limitations and future directions. Results: Nanotechnology can be used to stimulate osteoprogenitor differentiation in a variety of way. We have principally classified research into nanotechnology for bone tissue engineering as generating biomimetic scaffolds, a vector to deliver genes or growth factors to cells or to alter the biophysical environment. A number of studies have shown promising results with regards to directing ostroprogenitor cell differentiation although limitations include a lack of in vivo data and incomplete characterization of engineered bone. Conclusion: There is increasing evidence that nanotechnology can be used to direct the fate of osteoprogenitor and promote bone formation. Further analysis of the functional properties and long term survival in animal models is required to assess the maturity and clinical potential of this. PMID:28217210
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Measurement of Strain Distributions in Mouse Femora with 3D-Digital Speckle Pattern Interferometry
Yang, Lianxiang; Zhang, Ping; Liu, Sheng; Samala, Praveen R; Su, Min; Yokota, Hiroki
2007-01-01
Bone is a mechanosensitive tissue that adapts its mass, architecture and mechanical properties to external loading. Appropriate mechanical loads offer an effective means to stimulate bone remodeling and prevent bone loss. A role of in situ strain in bone is considered essential in enhancement of bone formation, and establishing a quantitative relationship between 3D strain distributions and a rate of local bone formation is important. Digital speckle pattern interferometry (DSPI) can achieve whole-field, non-contacting measurements of microscopic deformation for high-resolution determination of 3D strain distributions. However, the current system does not allow us to derive accurate strain distributions because of complex surface contours inherent to biological samples. Through development of a custom-made piezoelectric loading device as well as a new DSPI-based force calibration system, we built an advanced DSPI system and integrated local contour information to deformation data. Using a mouse femur in response to a knee loading modality as a model system, we determined 3D strain distributions and discussed effectiveness and limitations of the described system. PMID:18670581
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Margulies, B S; DeBoyace, S D; Damron, T A; Allen, M J
2015-10-01
Ewing's sarcoma of bone is a primary childhood malignancy of bone that is treated with X-radiation therapy in combination with surgical excision and chemotherapy. To better study Ewing's sarcoma of bone we developed a novel model of primary Ewing's sarcoma of bone and then treated animals with X-radiation therapy. We identified that uncontrolled tumor resulted in lytic bone destruction while X-radiation therapy decreased lytic bone destruction and increased limb-length asymmetry, a common, crippling complication of X-radiation therapy. Osteoclasts were indentified adjacent to the tumor, however, we were unable to detect RANK-ligand in the Ewing's tumor cells in vitro, which lead us to investigate alternate mechanisms for osteoclast formation. Ewing's sarcoma tumor cells and archival Ewing's sarcoma of bone tumor biopsy samples were shown to express MCSF, which could promote osteoclast formation. Increased monocyte numbers were detected in peripheral blood and spleen in animals with untreated Ewing's sarcoma tumor while monocyte number in animals treated with x-radiation had normal numbers of monocytes. Our data suggest that our Ewing's sarcoma of bone model will be useful in the study Ewing's sarcoma tumor progression in parallel with the effects of chemotherapy and X-radiation therapy. Copyright © 2015 Elsevier Inc. All rights reserved.
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Margulies, BS; DeBoyace, SD; Damron, TA; Allen, MJ
2015-01-01
Ewing's sarcoma of bone is a primary childhood malignancy of bone that is treated with X-radiation therapy in combination with surgical excision and chemotherapy. To better study Ewing's sarcoma of bone we developed a novel model of primary Ewing's sarcoma of bone and then treated animals with X-radiation therapy. We identified that uncontrolled tumor resulted in lytic bone destruction while X-radiation therapy decreased lytic bone destruction and increased limb-length asymmetry, a common, crippling complication of X-radiation therapy. Osteoclasts were indentified adjacent to the tumor, however, we were unable to detect RANK-ligand in the Ewing's tumor cells in vitro, which lead us to investigate alternate mechanisms for osteoclast formation. Ewing's sarcoma tumor cells and archival Ewing's sarcoma of bone tumor biopsy samples were shown to express MCSF, which could promote osteoclast formation. Increased monocyte numbers were detected in peripheral blood and spleen in animals with untreated Ewing's sarcoma tumor while monocyte number in animals treated with x-radiation had normal numbers of monocytes. Our data suggest that our Ewing's sarcoma of bone model will be useful in the study Ewing's sarcoma tumor progression in parallel with the effects of chemotherapy and X-radiation therapy. PMID:26051470
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NASA Technical Reports Server (NTRS)
Globus, Ruth K.; Searby, Nancy D.; Almeida, Eduardo A. C.; Sutijono, Darrell; Yu, Joon-Ho; Malouvier, Alexander; Doty, Steven B.; Morey-Holton, Emily; Weinstein, Steven L.; Dalton, Bonnie P. (Technical Monitor)
2000-01-01
Mechanical loading helps define the architecture of weight-bearing bone via the tightly regulated process of skeletal turnover. Turnover occurs by the concerted activity of osteoblasts, responsible for bone formation. and osteoclasts, responsible for bone resorption. Osteoclasts are specialized megakaryon macrophages, which differentiate from monocytes in response to resorption stimuli, such as reduced weight-bearing. Habitation in space dramatically alters musculoskeletal loading, which modulates both cell function and bone structure. Our long-term objective is to define the molecular and cellular mechanisms that mediate skeletal adaptations to altered gravity environments. Our experimental approach is to apply hypergravity loads by centrifugation to rodents and cultured cells. As a first step, we examined the influence of centrifugation on the structure of cancellous bone in rats to test the ability of hypergravity to change skeletal architecture. Since cancellous bone undergoes rapid turnover we expected the most dramatic structural changes to occur in the shape of trabeculae of weight-bearing, cancellous bone. To define the cellular responses to hypergravity loads, we exposed cultured osteoblasts and macrophages to centrifugation. The intraosseous and intramedullary pressures within long bones in vivo reportedly range from 12-40 mm Hg, which would correspond to 18-59 gravity (g) in our cultures. We assumed that hydrostatic pressure from the medium above the cell layer is at least one major component of the mechanical load generated by centrifuging cultured cells. and therefore we exposed the cells to 10-50g. In osteoblasts, we examined the structure of their actin and microtubule networks, production of prostaglandin E2 (PGE2), and cell survival. Analysis of the shape of the cytoskeletal networks provides evidence for the ability of centrifugation to affect cell structure, while the production of PGE2 serves as a convenient marker for mechanical stimulation. We examined cell survival, reasoning that osteoblasts might mold skeletal structure in a hypergravity environment in part by regulating apoptosis and thus the duration of osteoblast productivity. Finally, we tested the influence of centrifugation on microbial activation of a macrophage cell line (RAW264.7). In response to the appropriate hormonal stimulation, this cell line is reportedly capable of undergoing differentiation to express osteoclast markers. In addition, a component of the cell wall of gram-negative bacteria, lipopolysaccaride (LPS), stimulates the formation of osteoclasts in vivo. Thus we tested the influence on centrifugation on RAW264.7 cells stimulated with LPS to provide an index of the function of osteoclast precursors.
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Tomonaga, M; Jinnai, I; Tagawa, M; Amenomori, T; Nishino, K; Yao, E; Nonaka, H; Kuriyama, K; Yoshida, Y; Matsuo, T
1987-02-01
The bone marrow of a patient with acute undifferentiated leukemia developed unique colonies after a 14-day culture in erythropoietin (EPO)-containing methylcellulose. The colonies consisted of 20 to 200 nonhemoglobinized large blast cells. Cytogenetic analysis of single colonies revealed hypotetraploid karyotypes with several marker chromosomes that were identical to those found in directly sampled bone marrow. The concurrently formed erythroid bursts showed only normal karyotypes. No leukemic colony formation was observed in other culture systems with either colony-stimulating activity (CSA) or phytohemagglutinin-stimulated leukocyte-conditioned medium (PHA-LCM). The leukemic colonies exhibited a complete EPO-dose dependency similar to that of the patient's normal BFU-E. Although cytochemical and immunologic marker studies of the bone marrow cells failed to clarify the cell lineage of the leukemic cells with extraordinarily large cell size, ultrastructural study revealed erythroid differentiation such as siderosome formation in the cytoplasm and ferritin particles in the rhophecytosis invaginations. These findings indicate that the patient had poorly differentiated erythroid leukemia and that some of the clonogenic cells might respond to EPO in vitro. Corresponding to this biological feature, the leukemic cells were markedly decreased in number in response to repeated RBC transfusions, and partial remission was obtained. These observations suggest that erythroid leukemia distinct from erythroleukemia (M6) with a myeloblastic component, can develop as a minor entity of human acute leukemia.
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Mognetti, Barbara; Marino, Silvia; Barberis, Alessandro; Martin, Anne-Sophie Bravo; Bala, Yohann; Di Carlo, Francesco; Boivin, Georges; Barbos, Michele Portigliatti
2011-08-01
Fracture consolidation is a crucial goal to achieve as early as possible, but pharmacological stimulation has been neglected so far. Teriparatide has been considered for this purpose for its anabolic properties. We set up a murine model of closed tibial fracture on which different doses of teriparatide were tested. Closed fracture treatment avoids any bias introduced by surgical manipulations. Teriparatide's effect on callus formation was monitored during the first 4 weeks from fracture. Callus evolution was determined by histomorphometric and microhardness assessment. Daily administration of 40 μg/kg of teriparatide accelerated callus mineralization from day 9 onward without significant increase of sizes, and at day 15 the microhardness properties of treated callus were similar to those of bone tissue. Teriparatide considerably improved callus consolidation in the very early phases of bone healing.
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High-intensity exercise of short duration alters bovine bone density and shape.
Hiney, K M; Nielsen, B D; Rosenstein, D; Orth, M W; Marks, B P
2004-06-01
The ability of short-duration high-intensity exercise to stimulate bone formation in confinement was investigated using immature Holstein bull calves as a model. Eighteen bull calves, 8 wk of age, were assigned to one of three treatment groups: 1) group-housed (GR, which served as a control), 2) confined with no exercise (CF), or 3) confined with exercise (EX). The exercise protocol consisted of running 50 m on a concrete surface once daily, 5 d/wk. Confined calves remained stalled for the 42-d duration of the trial. Blood samples were taken to analyze concentrations of osteocalcin and deoxypyridinoline, markers of bone formation and resorption. At the completion of the trial, calves were humanely killed, and both forelegs were collected. The fused third and fourth metacarpal bone was scanned using computed tomography for determination of cross-sectional geometry and bone mineral density. Three-point bending tests to failure were performed on metacarpal bones. The exercise protocol resulted in the formation of a rounder bone in EX as well as in increased dorsal cortex thickness compared with those in the GR and CF. The exercised calves had a significantly smaller medullary cavity than CF and GR (P < 0.01) and a larger percentage of cortical bone area than CF (P < 0.01). Dorsal, palmar, and total bone mineral density was greater in EX than in CF (P < 0.05), and palmar and total bone mineral densities were greater (P < 0.05) in EX than in GR. There was a trend for the bones of EX to have a higher fracture force than CF (P < 0.10). Osteocalcin concentrations normalized from d 0 were higher in EX than CF (P < 0.05). Therefore, the exercise protocol altered bone shape and seemed to increase bone formation comparison with the stalled and group-housed calves.
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Takai, Hideki; Nakayama, Youhei; Kim, Dong-Soon; Arai, Masato; Araki, Shouta; Mezawa, Masaru; Nakajima, Yu; Kato, Naoko; Masunaga, Hiroshi; Ogata, Yorimasa
2007-09-01
Bone sialoprotein (BSP) is an early marker of osteoblast differentiation. Androgens are steroid hormones that are essential for skeletal development. The androgen receptor (AR) is a transcription factor and a member of the steroid receptor superfamily that plays an important role in male sexual differentiation and prostate cell proliferation. To determine the molecular mechanism involved in the stimulation of bone formation, we have analyzed the effects of androgens and AR effects on BSP gene transcription. AR protein levels were increased after AR overexpression in ROS17/2.8 cells. BSP mRNA levels were increased by AR overexpression. However, the endogenous and overexpressed BSP mRNA levels were not changed by DHT (10(-8) M, 24 h). Whereas luciferase (LUC) activities in all constructs, including a short construct (nts -116 to +60), were increased by AR overexpression, the basal and LUC activities enhanced by AR overexpression were not induced by DHT (10(-8)M, 24 h). The effect of AR overexpression was abrogated by 2 bp mutations in either the cAMP response element (CRE) or activator protein 1 (AP1)/glucocorticoid response element (GRE). Gel shift analyses showed that AR overexpression increased binding to the CRE and AP1/GRE elements. Notably, the CRE-protein complexes were supershifted by phospho-CREB antibody, and CREB, c-Fos, c-Jun, and AR antibodies disrupted the complexes formation. The AP1/GRE-protein complexes were supershifted by c-Fos antibody and c-Jun, and AR antibodies disrupted the complexes formation. These studies demonstrate that AR stimulates BSP gene transcription by targeting the CRE and AP1/GRE elements in the promoter of the rat BSP gene.
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Potential role of fibroblast growth factor in enhancement of fracture healing.
Radomsky, M L; Thompson, A Y; Spiro, R C; Poser, J W
1998-10-01
Fibroblast growth factors are present in significant amounts in bone and several studies have suggested that they may be involved in normal fracture healing. It is well established that fibroblast growth factors have mitogenic and angiogenic activity on mesoderm and neuroectoderm derived cells. Of particular interest as a member of the fibroblast growth factor family, basic fibroblast growth factor stimulates mitogenesis, chemotaxis, differentiation, and angiogenesis. It also plays an important role in the development of vascular, nervous, and skeletal systems, promotes the maintenance and survival of certain tissues, and stimulates wound healing and tissue repair. Animal studies have shown that the direct injection of fibroblast growth factor into fresh fractures stimulates callus formation, which provides mechanical stability to the fracture, accelerates healing, and restores competence. The matrix used to present the fibroblast growth factor at the fracture site plays a critical role in the effectiveness of the treatment. The evaluation of injectable basic fibroblast growth factor in a sodium hyaluronate gel for its effectiveness in stimulating fracture healing is described. When applied directly into a freshly created fracture in the rabbit fibula, a single injection of the basic fibroblast growth factor and hyaluronan results in the stimulation of callus formation, increased bone formation, and earlier restoration of mechanical strength at the fracture site. The hyaluronan gel serves as a reservoir that sequesters the basic fibroblast growth factor at the injection site for the length of time necessary to create an environment conducive to fracture healing. It is concluded that basic fibroblast growth factor and sodium hyaluronate act synergistically to accelerate fracture healing and that the combination is suitable for clinical evaluation as a therapy in fracture treatment.
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Li, Wei; Wang, Guanjun; Cui, Jiuwei; Xue, Lu; Cai, Lu
2004-11-01
The aim of this study was to investigate the stimulating effect of low-dose radiation (LDR) on bone marrow hematopoietic progenitor cell (HPC) proliferation and peripheral blood mobilization. Mice were exposed to 25- to 100-mGy x-rays. Bone marrow and peripheral blood HPCs (BFU-E, CFU-GM, and c-kit+ cells) were measured, and GM-CSF, G-CSF, and IL-3 protein and mRNA expression were detected using ELISA, slot blot hybridization, and Northern blot methods. To functionally evaluate LDR-stimulated and -mobilized HPCs, repopulation of peripheral blood cells in lethally irradiated recipients after transplantation of LDR-treated donor HPCs was examined by WBC counts, animal survival, and colony-forming units in the recipient spleens (CFUs-S). 75-mGy x-rays induced a maximal stimulation for bone marrow HPC proliferation (CFU-GM and BFU-E formation) 48 hours postirradiation, along with a significant increase in HPC mobilization into peripheral blood 48 to 72 hours postradiation, as shown by increases in CFU-GM formation and proportion of c-kit+ cells in the peripheral mononuclear cells. 75-mGy x-rays also maximally induced increases in G-CSF and GM-CSF mRNA expression in splenocytes and levels of serum GM-CSF. To define the critical role of these hematopoietic-stimulating factors in HPC peripheral mobilization, direct administration of G-CSF at a dose of 300 microg/kg/day or 150 microg/kg/day was applied and found to significantly stimulate GM-CFU formation and increase c-kit+ cells in the peripheral mononuclear cells. More importantly, 75-mGy x-rays plus 150 microg/kg/day G-CSF (LDR/150-G-CSF) produced a similar effect to that of 300 microg/kg/day G-CSF alone. Furthermore, the capability of LDR-mobilized donor HPCs to repopulate blood cells was confirmed in lethally irradiated recipient mice by counting peripheral WBC and CFUs-S. These results suggest that LDR induces hematopoietic hormesis, as demonstrated by HPC proliferation and peripheral mobilization, providing a potential approach to clinical application for HPC peripheral mobilization.
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Sclerostin Antibody Improves Skeletal Parameters in a Brtl/+ Mouse Model of Osteogenesis Imperfecta†
Sinder, Benjamin P.; Eddy, Mary M.; Ominsky, Michael S; Caird, Michelle S.; Marini, Joan C.; Kozloff, Kenneth M.
2012-01-01
Osteogenesis imperfecta (OI) is a genetic bone dysplasia characterized by osteopenia and easy susceptibility to fracture. Symptoms are most prominent during childhood. Although anti-resorptive bisphosphonates have been widely used to treat pediatric OI, controlled trials showed improved vertebral parameters but equivocal effects on long-bone fracture rates. New treatments for OI are needed to increase bone mass throughout the skeleton. Sclerostin antibody (Scl-Ab) therapy is potently anabolic in the skeleton by stimulating osteoblasts via the canonical wnt signaling pathway, and may be beneficial for treating OI. In this study, Scl-Ab therapy was investigated in mice heterozygous for a typical OI-causing Gly->Cys substitution in col1a1. Two weeks of Scl-Ab successfully stimulated osteoblast bone formation in Brtl/+ and WT mice, leading to improved bone mass and reduced long-bone fragility. Image-guided nanoindentation revealed no alteration in local tissue mineralization dynamics with Scl-Ab. These results contrast with previous findings of antiresorptive efficacy in OI both in mechanism and potency of effects on fragility. In conclusion, short-term Scl-Ab was successfully anabolic in osteoblasts harboring a typical OI-causing collagen mutation and represents a potential new therapy to improve bone mass and reduce fractures in pediatric OI. PMID:22836659
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Ayranci, Ferhat; Gungormus, Metin; Omezli, Mehmet Melih; Gundogdu, Betul
2015-12-01
Increasing sinus pneumatization and the accompanying alveolar bone resorption complicate dental implant placement. This problem can be overcome today by raising the maxillary sinus floor with graft materials. Bisphosphonates are commonly used to accelerate the recovery of the graft materials and to prevent resorption. The purpose of this study is to investigate whether systemic administration of a bisphosphonate (alendronate) would improve new bone formation and reduce fibrous tissue formation over a 6-week follow-up in rabbits treated with two different grafting materials for maxillary sinus floor augmentation. This experimental animal study was conducted at the Experimental Medical Application and Research Center at Erzurum/ Turkey. Twelve New Zealand rabbits, each weighing between 2.7 and 3.3 kg, were used. Twenty-four maxillary sinus floor elevation operations were performed, two on each animal (n = 24). Each elevation was repaired with either deproteinized bovine bone (xenograft) or autogenous bone graft obtained from the iliac crest. Both groups were divided into 2 subgroups: saline-treated and alendronate-treated. All groups underwent the same surgical procedures and evaluation, and were sacrificed at the 6th postoperative week. Sinuses augmented with deproteinized bovine bone (xenograft) and autogenous bone graft were examined histopathologically and histomorphometrically. At 6 weeks, the bone area was significantly larger in the Xenograft-Alendronate group (33.0% ± 5.0%) than in the Xenograft-Saline group (20.8% ± 4.9%) and the bone area was significantly larger in the Autogenous-Alendronate group (43.3% ± 3.8%) than in the Autogenous-Saline group (37.5% ± 6.6%) (P = 0.001). The histomorphometric and histopathological results consistently showed that alendronate stimulated bone formation and reduced fibrous tissue formation in maxillary sinus augmentation grafts, especially in the deproteinized bovine bone group (xenograft). Alendronate may be considered a therapeutic option for improving the bone formation process and reducing resorption in different bone grafting procedures. Further detailed studies should focus on dosage and time-dependent effects of alendronate on bone remodeling.
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Ayranci, Ferhat; Gungormus, Metin; Omezli, Mehmet Melih; Gundogdu, Betul
2015-01-01
Background: Increasing sinus pneumatization and the accompanying alveolar bone resorption complicate dental implant placement. This problem can be overcome today by raising the maxillary sinus floor with graft materials. Bisphosphonates are commonly used to accelerate the recovery of the graft materials and to prevent resorption. Objectives: The purpose of this study is to investigate whether systemic administration of a bisphosphonate (alendronate) would improve new bone formation and reduce fibrous tissue formation over a 6-week follow-up in rabbits treated with two different grafting materials for maxillary sinus floor augmentation. Materials and Methods: This experimental animal study was conducted at the Experimental Medical Application and Research Center at Erzurum/ Turkey. Twelve New Zealand rabbits, each weighing between 2.7 and 3.3 kg, were used. Twenty-four maxillary sinus floor elevation operations were performed, two on each animal (n = 24). Each elevation was repaired with either deproteinized bovine bone (xenograft) or autogenous bone graft obtained from the iliac crest. Both groups were divided into 2 subgroups: saline-treated and alendronate-treated. All groups underwent the same surgical procedures and evaluation, and were sacrificed at the 6th postoperative week. Sinuses augmented with deproteinized bovine bone (xenograft) and autogenous bone graft were examined histopathologically and histomorphometrically. Results: At 6 weeks, the bone area was significantly larger in the Xenograft-Alendronate group (33.0% ± 5.0%) than in the Xenograft-Saline group (20.8% ± 4.9%) and the bone area was significantly larger in the Autogenous-Alendronate group (43.3% ± 3.8%) than in the Autogenous-Saline group (37.5% ± 6.6%) (P = 0.001). The histomorphometric and histopathological results consistently showed that alendronate stimulated bone formation and reduced fibrous tissue formation in maxillary sinus augmentation grafts, especially in the deproteinized bovine bone group (xenograft). Conclusions: Alendronate may be considered a therapeutic option for improving the bone formation process and reducing resorption in different bone grafting procedures. Further detailed studies should focus on dosage and time-dependent effects of alendronate on bone remodeling. PMID:26756022
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Terra, Silvia R; Cardoso, João Carlos R; Félix, Rute C; Martins, Leo Anderson M; Souza, Diogo Onofre G; Guma, Fatima C R; Canário, Adelino Vicente M; Schein, Vanessa
2015-03-05
Stanniocalcin 1 (STC1) and calcitonin gene-related peptide (CGRP) are involved in bone formation/remodeling. Here we investigate the effects of STC1 on functional heterodimer complex CALCRL/RAMP1, expression and activity during osteoblastogenesis. STC1 did not modify CALCRL and ramp1 gene expression during osteoblastogenesis when compared to controls. However, plasma membrane spatial distribution of CALCRL/RAMP1 was modified in 7-day pre-osteoblasts exposed to either CGRP or STC1, and both peptides induced CALCRL and RAMP1 assembly. CGRP, but not STC1 stimulated cAMP accumulation in 7-day osteoblasts and in CALCRL/RAMP1 transfected HEK293 cells. Furthermore, STC1 inhibited forskolin stimulated cAMP accumulation of HEK293 cells, but not in CALCRL/RAMP1 transfected HEK293 cells. However, STC1 inhibited cAMP accumulation in calcitonin receptor (CTR) HEK293 transfected cells stimulated by calcitonin. In conclusion, STC1 signals through inhibitory G-protein modulates CGRP receptor spatial localization during osteoblastogenesis and may function as a regulatory factor interacting with calcitonin peptide members during bone formation. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
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Koskinen, Cecilia; Persson, Emelie; Baldock, Paul; Stenberg, Åsa; Boström, Ingrid; Matozaki, Takashi; Oldenborg, Per-Arne; Lundberg, Pernilla
2013-01-01
Here, we investigated whether the cell surface glycoprotein CD47 was required for normal formation of osteoblasts and osteoclasts and to maintain normal bone formation activity in vitro and in vivo. In parathyroid hormone or 1α,25(OH)2-vitamin D3 (D3)-stimulated bone marrow cultures (BMC) from CD47−/− mice, we found a strongly reduced formation of multinuclear tartrate-resistant acid phosphatase (TRAP)+ osteoclasts, associated with reduced expression of osteoclastogenic genes (nfatc1, Oscar, Trap/Acp, ctr, catK, and dc-stamp). The production of M-CSF and RANKL (receptor activator of nuclear factor κβ ligand) was reduced in CD47−/− BMC, as compared with CD47+/+ BMC. The stromal cell phenotype in CD47−/− BMC involved a blunted expression of the osteoblast-associated genes osterix, Alp/Akp1, and α-1-collagen, and reduced mineral deposition, as compared with that in CD47+/+ BMC. CD47 is a ligand for SIRPα (signal regulatory protein α), which showed strongly reduced tyrosine phosphorylation in CD47−/− bone marrow stromal cells. In addition, stromal cells lacking the signaling SIRPα cytoplasmic domain also had a defect in osteogenic differentiation, and both CD47−/− and non-signaling SIRPα mutant stromal cells showed a markedly reduced ability to support osteoclastogenesis in wild-type bone marrow macrophages, demonstrating that CD47-induced SIRPα signaling is critical for stromal cell support of osteoclast formation. In vivo, femoral bones of 18- or 28-week-old CD47−/− mice showed significantly reduced osteoclast and osteoblast numbers and exhibited an osteopenic bone phenotype. In conclusion, lack of CD47 strongly impairs SIRPα-dependent osteoblast differentiation, deteriorate bone formation, and cause reduced formation of osteoclasts. PMID:23990469
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Colaianni, G.; Tamma, R.; Di Benedetto, A.; Yuen, T.; Sun, L.; Zaidi, M.; Zallone, A.
2014-01-01
We recently demonstrated a direct action of oxytocin (OT) on skeletal homeostasis mainly mediated through stimulation of osteoblasts (OBs) formation and through the reciprocal modulation of osteoclast (OCs) formation and function. Thus, mice lacking the hormone or its receptor develop a low turnover osteoporosis that worsens with age in both sexes. The skeleton of OT and OT receptor (Oxtr) null mice display a pronounced decrease in vertebral and femoral trabecular volume. At cellular level OBs from OT−/− and Oxtr−/− mice exhibit lower mineralization activity and, at mRNA level, all master genes for osteoblast differentiation are down regulated. Moreover, OT has dual effects on OCs: it increases osteoclast formation both directly, by activating NF-kB and MAP kinase signaling, and indirectly, through the up-regulation of RANK-L synthesis by OBs. On the other hand, it inhibits bone resorption by triggering cytosolic Ca2+ release and nitric oxide synthesis in mature OCs. OT is locally produced by osteoblasts acting as paracrine-autocrine regulator of bone formation modulated by estrogens. The estrogen signal involved in this feed forward circuit is non genomic, since it requires an intact MAPK kinase signal transduction pathway, instead of the classical nuclear translocation of estrogen receptor. The ability of estrogen to increase bone mass in vivo is to an extent OTR-dependent. Thus Oxtr−/− mice injected 17β-estradiol did not show any effects on bone formation parameters, while the same treatment increases trabecular and cortical bone in wild type mice. An intact OT autocrine-paracrine circuit seems to be essential for optimal skeletal remodeling. PMID:24219627
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Articular Cartilage Increases Transition Zone Regeneration in Bone-tendon Junction Healing
Qin, Ling; Lee, Kwong Man; Leung, Kwok Sui
2008-01-01
The fibrocartilage transition zone in the direct bone-tendon junction reduces stress concentration and protects the junction from failure. Unfortunately, bone-tendon junctions often heal without fibrocartilage transition zone regeneration. We hypothesized articular cartilage grafts could increase fibrocartilage transition zone regeneration. Using a goat partial patellectomy repair model, autologous articular cartilage was harvested from the excised distal third patella and interposed between the residual proximal two-thirds bone fragment and tendon during repair in 36 knees. We evaluated fibrocartilage transition zone regeneration, bone formation, and mechanical strength after repair at 6, 12, and 24 weeks and compared them with direct repair. Autologous articular cartilage interposition resulted in more fibrocartilage transition zone regeneration (69.10% ± 14.11% [mean ± standard deviation] versus 8.67% ± 7.01% at 24 weeks) than direct repair at all times. There was no difference in the amount of bone formation and mechanical strength achieved. Autologous articular cartilage interposition increases fibrocartilage transition zone regeneration in bone-tendon junction healing, but additional research is required to ascertain the mechanism of stimulation and to establish the clinical applicability. PMID:18987921
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Single-Stranded γPNAs for In Vivo Site-Specific Genome Editing via Watson-Crick Recognition
Bahal, Raman; Quijano, Elias; McNeer, Nicole Ali; Liu, Yanfeng; Bhunia, Dinesh C.; López-Giráldez, Francesco; Fields, Rachel J.; Saltzman, W. Mark; Ly, Danith H.; Glazer, Peter M.
2014-01-01
Triplex-forming peptide nucleic acids (PNAs) facilitate gene editing by stimulating recombination of donor DNAs within genomic DNA via site-specific formation of altered helical structures that further stimulate DNA repair. However, PNAs designed for triplex formation are sequence restricted to homopurine sites. Herein we describe a novel strategy where next generation single-stranded gamma PNAs (γPNAs) containing miniPEG substitutions at the gamma position can target genomic DNA in mouse bone marrow at mixed-sequence sites to induce targeted gene editing. In addition to enhanced binding, γPNAs confer increased solubility and improved formulation into poly(lactic-co-glycolic acid) (PLGA) nanoparticles for efficient intracellular delivery. Single-stranded γPNAs induce targeted gene editing at frequencies of 0.8% in mouse bone marrow cells treated ex vivo and 0.1% in vivo via IV injection, without detectable toxicity. These results suggest that γPNAs may provide a new tool for induced gene editing based on Watson-Crick recognition without sequence restriction. PMID:25174576
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Single-stranded γPNAs for in vivo site-specific genome editing via Watson-Crick recognition.
Bahal, Raman; Quijano, Elias; McNeer, Nicole A; Liu, Yanfeng; Bhunia, Dinesh C; Lopez-Giraldez, Francesco; Fields, Rachel J; Saltzman, William M; Ly, Danith H; Glazer, Peter M
2014-01-01
Triplex-forming peptide nucleic acids (PNAs) facilitate gene editing by stimulating recombination of donor DNAs within genomic DNA via site-specific formation of altered helical structures that further stimulate DNA repair. However, PNAs designed for triplex formation are sequence restricted to homopurine sites. Herein we describe a novel strategy where next generation single-stranded gamma PNAs (γPNAs) containing miniPEG substitutions at the gamma position can target genomic DNA in mouse bone marrow at mixed-sequence sites to induce targeted gene editing. In addition to enhanced binding, γPNAs confer increased solubility and improved formulation into poly(lactic-co-glycolic acid) (PLGA) nanoparticles for efficient intracellular delivery. Single-stranded γPNAs induce targeted gene editing at frequencies of 0.8% in mouse bone marrow cells treated ex vivo and 0.1% in vivo via IV injection, without detectable toxicity. These results suggest that γPNAs may provide a new tool for induced gene editing based on Watson-Crick recognition without sequence restriction.
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Furuya, Yuriko; Inagaki, Atsushi; Khan, Masud; Mori, Kaoru; Penninger, Josef M.; Nakamura, Midori; Udagawa, Nobuyuki; Aoki, Kazuhiro; Ohya, Keiichi; Uchida, Kohji; Yasuda, Hisataka
2013-01-01
To date, parathyroid hormone is the only clinically available bone anabolic drug. The major difficulty in the development of such drugs is the lack of clarification of the mechanisms regulating osteoblast differentiation and bone formation. Here, we report a peptide (W9) known to abrogate osteoclast differentiation in vivo via blocking receptor activator of nuclear factor-κB ligand (RANKL)-RANK signaling that we surprisingly found exhibits a bone anabolic effect in vivo. Subcutaneous administration of W9 three times/day for 5 days significantly augmented bone mineral density in mouse cortical bone. Histomorphometric analysis showed a decrease in osteoclastogenesis in the distal femoral metaphysis and a significant increase in bone formation in the femoral diaphysis. Our findings suggest that W9 exerts bone anabolic activity. To clarify the mechanisms involved in this activity, we investigated the effects of W9 on osteoblast differentiation/mineralization in MC3T3-E1 (E1) cells. W9 markedly increased alkaline phosphatase (a marker enzyme of osteoblasts) activity and mineralization as shown by alizarin red staining. Gene expression of several osteogenesis-related factors was increased in W9-treated E1 cells. Addition of W9 activated p38 MAPK and Smad1/5/8 in E1 cells, and W9 showed osteogenesis stimulatory activity synergistically with BMP-2 in vitro and ectopic bone formation. Knockdown of RANKL expression in E1 cells reduced the effect of W9. Furthermore, W9 showed a weak effect on RANKL-deficient osteoblasts in alkaline phosphatase assay. Taken together, our findings suggest that this peptide may be useful for the treatment of bone diseases, and W9 achieves its bone anabolic activity through RANKL on osteoblasts accompanied by production of several autocrine factors. PMID:23319583
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Short bursts of cyclic mechanical compression modulate tissue formation in a 3D hybrid scaffold.
Brunelli, M; Perrault, C M; Lacroix, D
2017-07-01
Among the cues affecting cells behaviour, mechanical stimuli are known to have a key role in tissue formation and mineralization of bone cells. While soft scaffolds are better at mimicking the extracellular environment, they cannot withstand the high loads required to be efficient substitutes for bone in vivo. We propose a 3D hybrid scaffold combining the load-bearing capabilities of polycaprolactone (PCL) and the ECM-like chemistry of collagen gel to support the dynamic mechanical differentiation of human embryonic mesodermal progenitor cells (hES-MPs). In this study, hES-MPs were cultured in vitro and a BOSE Bioreactor was employed to induce cells differentiation by mechanical stimulation. From day 6, samples were compressed by applying a 5% strain ramp followed by peak-to-peak 1% strain sinewaves at 1Hz for 15min. Three different conditions were tested: unloaded (U), loaded from day 6 to day 10 (L1) and loaded as L1 and from day 16 to day 20 (L2). Cell viability, DNA content and osteocalcin expression were tested. Samples were further stained with 1% osmium tetroxide in order to investigate tissue growth and mineral deposition by micro-computed tomography (µCT). Tissue growth involved volumes either inside or outside samples at day 21 for L1, suggesting cyclic stimulation is a trigger for delayed proliferative response of cells. Cyclic load also had a role in the mineralization process preventing mineral deposition when applied at the early stage of culture. Conversely, cyclic load during the late stage of culture on pre-compressed samples induced mineral formation. This study shows that short bursts of compression applied at different stages of culture have contrasting effects on the ability of hES-MPs to induce tissue formation and mineral deposition. The results pave the way for a new approach using mechanical stimulation in the development of engineered in vitro tissue as replacement for large bone fractures. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Yao, Jian-fei; Shen, Jia-zuo; Li, Da-kun; Lin, Da-sheng; Li, Lin; Li, Qiang; Qi, Peng; Lian, Ke-jian; Ding, Zhen-qi
2012-01-01
Lower tibial bone fracture may easily cause bone delayed union or nonunion because of lacking of dynamic mechanical load. Research Group would design a new instrument as Rap System of Stress Stimulation (RSSS) to provide dynamic mechanical load which would promote lower tibial bone union postoperatively. This clinical research was conducted from January 2008 to December 2010, 92 patients(male 61/female 31, age 16-70 years, mean 36.3 years) who suffered lower tibial bone closed fracture were given intramedullary nail fixation and randomly averagely separated into experimental group and control group(according to the successively order when patients went for the admission procedure). Then researchers analysed the clinical healing time, full weight bearing time, VAS (Visual Analogue Scales) score and callus growth score of Lane-Sandhu in 3,6,12 months postoperatively. The delayed union and nonunion rates were compared at 6 and 12 months separately. All the 92 patients had been followed up (mean 14 months). Clinical bone healing time in experimental group was 88.78±8.80 days but control group was 107.91±9.03 days. Full weight bearing time in experimental group was 94.07±9.81 days but control group was 113.24±13.37 days respectively (P<0.05). The delayed union rate in 6 months was 4.3% in experimental group but 10.9% in control group(P<0.05). The nonunion rate in 12 months was 6.5% in experimental group but 19.6% in control group(P<0.05). In 3, 6, 12 months postoperatively, VAS score and Lane-Sandhu score in experimental group had more significantly difference than them in control group. RSSS can intermittently provide dynamic mechanical load and stimulate callus formation, promote lower tibial bone union, reduce bone delayed union or nonunion rate. It is an adjuvant therapy for promoting bone union after lower tibial bone fracture.
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A collaboration investigating endocannabinoid signalling in brain and bone.
Zimmer, Andreas
2016-05-01
Investigations into the cellular and molecular mechanisms underlying the psychoactive effects of cannabis preparations have led to the discovery of the endocannabinoid system. Interest in the central nervous system effects was initially the main focus of the research, but it soon became evident that the endocannabinoid system affects virtually every organ. The research field has therefore experienced a tremendous growth over the last decade and is now truly interdisciplinary. This short review provides a personal account of an interdisciplinary collaboration between Itai Bab from the Hebrew University of Jerusalem and the author. It describes the discovery of the endocannabinoid system in bone and the analysis of its functions. I am summarising the role of CB1 signalling as a modulator of sympathetic inhibition of bone formation. Thus, activation of CB1 receptors on sympathetic nerve terminals in bone, presumably from endocannabinoids released from apposing osteoblasts, reduces the inhibition of bone formation of sympathetic norepinephrine. CB2 receptors on osteoblasts and osteoclasts also modulate the proliferation and functions of these cells. Thus, activation of CB2 stimulates bone formation and represses bone resorption, whereas the genetic disruption of CB2 results in an osteoporosis-like phenotype. This signalling mechanism is clinically relevant, as shown by the association of polymorphisms in the CB2 receptor gene, CNR2, with bone density and osteoporosis. Finally, the review provides a summary of the recently discovered role of endocannabinoid signalling in one elongation. This review will also discuss the benefits of interdisciplinary and international collaborations.
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Acute bone response to whole body vibration in healthy pre-pubertal boys
Harrison, R.; Ward, K.; Lee, E.; Razaghi, H.; Horne, C.; Bishop, N.J.
2015-01-01
The skeleton responds to mechanical stimulation. We wished to ascertain the magnitude and speed of the growing skeleton’s response to a standardised form of mechanical stimulation, vibration. 36 prepubertal boys stood for 10 minutes in total on one of two vibrating platforms (high (>2 g) or low (<1 g) magnitude vibration) on either 1, 3 or 5 successive days (n=12 for each duration); 15 control subjects stood on an inactive platform. Blood samples were taken at intervals before and after vibration to measure bone formation (P1NP, osteocalcin) and resorption (CTx) markers as well as osteoprotegerin and sclerostin. There were no significant differences between platform and control groups in bone turnover markers immediately after vibration on days 1, 3 and 5. Combining platform groups, at day 8 P1NP increased by 25.1% (CI 12.3 to 38.0; paired t-test p=0.005) and bone resorption increased by 10.9% (CI 3.6 to 18.2; paired t-test p=0.009) compared to baseline. Osteocalcin, osteoprotogerin and sclerostin did not change significantly. The growing skeleton can respond quickly to vibration of either high or low magnitude. Further work is needed to determine the utility of such “stimulation-testing” in clinical practice. PMID:26032203
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Acute bone response to whole body vibration in healthy pre-pubertal boys.
Harrison, R; Ward, K; Lee, E; Razaghi, H; Horne, C; Bishop, N J
2015-06-01
The skeleton responds to mechanical stimulation. We wished to ascertain the magnitude and speed of the growing skeleton's response to a standardised form of mechanical stimulation, vibration. 36 prepubertal boys stood for 10 minutes in total on one of two vibrating platforms (high (>2 g) or low (<1 g) magnitude vibration) on either 1, 3 or 5 successive days (n=12 for each duration); 15 control subjects stood on an inactive platform. Blood samples were taken at intervals before and after vibration to measure bone formation (P1NP, osteocalcin) and resorption (CTx) markers as well as osteoprotegerin and sclerostin. There were no significant differences between platform and control groups in bone turnover markers immediately after vibration on days 1, 3 and 5. Combining platform groups, at day 8 P1NP increased by 25.1% (CI 12.3 to 38.0; paired t-test p=0.005) and bone resorption increased by 10.9% (CI 3.6 to 18.2; paired t-test p=0.009) compared to baseline. Osteocalcin, osteoprotogerin and sclerostin did not change significantly. The growing skeleton can respond quickly to vibration of either high or low magnitude. Further work is needed to determine the utility of such "stimulation-testing" in clinical practice.
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Hirasawa, Hideyuki; Tanaka, Shinya; Sakai, Akinori; Tsutsui, Masato; Shimokawa, Hiroaki; Miyata, Hironori; Moriwaki, Sawako; Niida, Shumpei; Ito, Masako; Nakamura, Toshitaka
2007-07-01
Osteoblast apoptosis increased in the tibias of apoE(-/-) mice fed with a high-fat diet, decreasing bone formation. The expression of p53 mRNA in marrow adherent cells increased. LDL or oxidized LDL increased apoptosis in the calvarial cells of apoE(-/-) mice. The increase in p53-mediated apoptosis is apparently related to a high-fat diet-induced osteopenia in apoE(-/-) mice. The effects of high-fat loading and the apolipoprotein E (apoE) gene on bones have not been elucidated. We hypothesized that apoE gene deficiency (apoE(-/-)) modulates the effects of high-fat loading on bones. We assessed this hypothesis using wildtype (WT) and apoE(-/-) mice fed a standard (WTS and ApoES groups) or a high-fat diet (WTHf and ApoEHf groups). The concentration of serum lipid levels and bone chemical markers were measured. Histomorphometry of the femurs was performed using microCT and a microscope. Bone marrow adherent cells from the femurs were used for colony-forming unit (CFU)-fibroblastic (CFU-f) assay and mRNA expressions analysis. The apoptotic cells in the tibias were counted. TUNEL fluorescein assay and Western analysis were performed in cultures of calvarial cells by the addition of low-density lipoprotein (LDL) or oxidized LDL. In the ApoEHf group, the values of cortical bone volume and trabecular and endocortical bone formation of the femurs decreased, and urinary deoxypyridinoline increased. Subsequent analysis revealed that the number of apoptotic cells in the tibias of the ApoES group increased, and more so in the ApoEHf group. The ratio of alkaline phosphatase-positive CFU-f to total CFU-f was decreased in the ApoEHf group. p53 mRNA expression in adherent cells of the apoE(-/-) mice increased and had a significantly strong positive correlation with serum LDL. TUNEL fluorescein assay of osteoblastic cells revealed an increase of apoptotic cells in the apoE(-/-) mice. The number of apoptotic cells in the apoE(-/-) mice increased with the addition of 100 microg/ml LDL or oxidized LDL. The p53 protein expression in apoE(-/-) cells exposed to 100 microg/ml LDL or oxidized LDL increased. We concluded that apoE gene deficiency enhances the reduction of bone formation induced by a high-fat diet through the stimulation of p53-mediated apoptosis in osteoblastic cells.
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Sost, independent of the non-coding enhancer ECR5, is required for bone mechanoadaptation
DOE Office of Scientific and Technical Information (OSTI.GOV)
Robling, Alexander G.; Kang, Kyung Shin; Bullock, Whitney A.
Here, sclerostin ( Sost) is a negative regulator of bone formation that acts upon the Wnt signaling pathway. Sost is mechanically regulated at both mRNA and protein level such that loading represses and unloading enhances Sost expression, in osteocytes and in circulation. The non-coding evolutionarily conserved enhancer ECR5 has been previously reported as a transcriptional regulatory element required for modulating Sost expression in osteocytes. Here we explored the mechanisms by which ECR5, or several other putative transcriptional enhancers regulate Sost expression, in response to mechanical stimulation. We found that in vivo ulna loading is equally osteoanabolic in wildtype and Sostmore » –/– mice, although Sost is required for proper distribution of load-induced bone formation to regions of high strain. Using Luciferase reporters carrying the ECR5 non-coding enhancer and heterologous or homologous h SOST promoters, we found that ECR5 is mechanosensitive in vitro and that ECR5-driven Luciferase activity decreases in osteoblasts exposed to oscillatory fluid flow. Yet, ECR5–/– mice showed similar magnitude of load-induced bone formation and similar periosteal distribution of bone formation to high-strain regions compared to wildtype mice. Further, we found that in contrast to Sost–/– mice, which are resistant to disuse-induced bone loss, ECR5–/– mice lose bone upon unloading to a degree similar to wildtype control mice. ECR5 deletion did not abrogate positive effects of unloading on Sost, suggesting that additional transcriptional regulators and regulatory elements contribute to load-induced regulation of Sost.« less
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Sost, independent of the non-coding enhancer ECR5, is required for bone mechanoadaptation
Robling, Alexander G.; Kang, Kyung Shin; Bullock, Whitney A.; ...
2016-09-04
Here, sclerostin ( Sost) is a negative regulator of bone formation that acts upon the Wnt signaling pathway. Sost is mechanically regulated at both mRNA and protein level such that loading represses and unloading enhances Sost expression, in osteocytes and in circulation. The non-coding evolutionarily conserved enhancer ECR5 has been previously reported as a transcriptional regulatory element required for modulating Sost expression in osteocytes. Here we explored the mechanisms by which ECR5, or several other putative transcriptional enhancers regulate Sost expression, in response to mechanical stimulation. We found that in vivo ulna loading is equally osteoanabolic in wildtype and Sostmore » –/– mice, although Sost is required for proper distribution of load-induced bone formation to regions of high strain. Using Luciferase reporters carrying the ECR5 non-coding enhancer and heterologous or homologous h SOST promoters, we found that ECR5 is mechanosensitive in vitro and that ECR5-driven Luciferase activity decreases in osteoblasts exposed to oscillatory fluid flow. Yet, ECR5–/– mice showed similar magnitude of load-induced bone formation and similar periosteal distribution of bone formation to high-strain regions compared to wildtype mice. Further, we found that in contrast to Sost–/– mice, which are resistant to disuse-induced bone loss, ECR5–/– mice lose bone upon unloading to a degree similar to wildtype control mice. ECR5 deletion did not abrogate positive effects of unloading on Sost, suggesting that additional transcriptional regulators and regulatory elements contribute to load-induced regulation of Sost.« less
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Alkaline biodegradable implants for osteoporotic bone defects--importance of microenvironment pH.
Liu, W; Wang, T; Yang, C; Darvell, B W; Wu, J; Lin, K; Chang, J; Pan, H; Lu, W W
2016-01-01
Change of microenvironment pH by biodegradable implants may ameliorate unbalanced osteoporotic bone remodeling. The present work demonstrated that a weak alkaline condition stimulated osteoblasts differentiation while suppressed osteoclast generation. In vivo, implants with an alkaline microenvironment pH (monitored by a pH microelectrode) exhibited a promising healing effect for the repair of osteoporotic bone defects. Under osteoporotic conditions, the response of the bone microenvironment to an endosseous implant is significantly impaired, and this substantially increases the risk of fracture, non-union and aseptic implant loosening. Acid-base equilibrium is an important factor influencing bone cell behaviour. The present purpose was to study the effect of a series of alkaline biodegradable implant materials on regeneration of osteoporotic bone defect, monitoring the microenvironment pH (μe-pH) over time. The proliferation and differentiation potential of osteoporotic rat bone marrow stromal cells and RAW 264.7 cells were examined under various pH conditions. Ovariectomized rat bone defects were filled with specific biodegradable materials, and μe-pH was measured by pH microelectrode. New osteoid and tartrate-resistant acid phosphatase-positive osteoclast-like cells were examined by Goldner's trichrome and TRAP staining, respectively. The intermediate layer between implants and new bone were studied using energy-dispersive X-ray spectroscopy (EDX) linear scanning. In vitro, weak alkaline conditions stimulated osteoporotic rat bone marrow stromal cells (oBMSC) differentiation, while inhibiting the formation of osteoclasts. In vivo, μe-pH differs from that of the homogeneous peripheral blood and exhibits variations over time particular to each material. Higher initial μe-pH was associated with more new bone formation, late response of TRAP-positive osteoclast-like cells and the development of an intermediate 'apatitic' layer in vivo. EDX suggested that residual material may influence μe-pH even 9 weeks post-surgery. The pH microelectrode is suitable for in vivo μe-pH detection. Alkaline biodegradable materials generate an in vivo microenvironmental pH which is higher than the normal physiological value and show promising healing effects in the context of osteoporotic bone defects.
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Wise, Joel K.; Sumner, Dale Rick
2012-01-01
Enhancement of in vivo mobilization and homing of endogenous mesenchymal stem cells (MSCs) to an injury site is an innovative strategy for improvement of bone tissue engineering and repair. The present study was designed to determine whether mobilization by AMD3100 and/or local homing by delivery of stromal cell-derived factor-1 (SDF-1) enhances recombinant human bone morphogenetic protein-2 (rhBMP-2) induced ectopic bone formation in an established rat model. Rats received an injection of either saline or AMD3100 treatment 1 h before harvesting of bone marrow for in vitro colony-forming unit-fibroblasts (CFU-F) culture or the in vivo subcutaneous implantation of absorbable collagen sponges (ACSs) loaded with saline, recombinant human bone morphogenetic protein-2 (rhBMP-2), SDF-1, or the combination of SDF-1 and rhBMP-2. AMD3100 treatment resulted in a significant decrease in CFU-F number, compared with saline, which confirmed that a single systemic AMD3100 treatment rapidly mobilized MSCs from the bone marrow. At 28 and 56 days, bone formation in the explanted ACS was assessed by microcomputed tomography (μCT) and histology. At 28 days, AMD3100 and/or SDF-1 had no statistically significant effect on bone volume (BV) or bone mineral content (BMC), but histology revealed more active bone formation with treatment of AMD3100, loading of SDF-1, or the combination of both AMD3100 and SDF-1, compared with saline-treated rhBMP-2 loaded ACS. At 56 days, the addition of AMD3100 treatment, loading of SDF-1, or the combination of both resulted in a statistically significant stimulatory effect on BV and BMC, compared with the saline-treated rhBMP-2 loaded ACS. Histology of the 56-day ACS were consistent with the μCT analysis, exhibiting more mature and mineralized bone formation with AMD3100 treatment, SDF-1 loading, or the combination of both, compared with the saline-treated rhBMP-2 loaded ACS. The present study is the first that provides evidence of the efficacy of AMD3100 and SDF-1 treatment to stimulate trafficking of MSCs to an ectopic implant site, in order to ultimately enhance rhBMP-2 induced long-term bone formation. PMID:22035136
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Fluorosis increases the risk of postmenopausal osteoporosis by stimulating interferon γ.
Lv, Yun-Gang; Kang, Li; Wu, Guangyao
2016-10-14
Estrogen deficiency in postmenopausal women frequently activates osteoclasts (OC), accelerates bone resorption, and leads to osteoporosis (OP). Previous studies have demonstrated that interferon γ (IFNγ) could increase bone resorption and may be involved in postmenopausal OP. Fluorosis also increased the risk of fractures and dental fluorosis, and fluoride may enhance osteoclast formation and induce osteoclastic bone destruction in postmenopausal women, but the underlying mechanisms are as yet unknown. Here, we show that serum fluoride and IFNγ levels are negatively correlated with bone mineral density (BMD) in postmenopausal women residing in a fluorotic area. Estrogen suppresses IFNγ, which is elevated by fluoride, playing a pivotal role in triggering bone loss in estrogen-deficient conditions. In vitro, IFNγ is inhibited by estrogen treatment and increased by fluoride in Raw264.7 cell, an osteoclast progenitor cell line. In ovariectomized (Ovx) mice, estrogen loss and IFNγ promote OC activation and subsequent bone loss in vivo. However, IFNγ deficiency prevents bone loss in Ovx mice even in fluoride conditions. Interestingly, fluoride fails to increase IFNγ expression in estrogen receptor α (ERα)-deficient conditions, but not in ERβ-deficient conditions. These findings demonstrate that fluorosis increases the bone loss in postmenopausal OP through an IFNγ-dependent mechanism. IFNγ signaling activates OC and aggravates estrogen deficiency inducing OP. Thus, stimulation of IFNγ production is a pivotal ''upstream'' mechanism by which fluoride promotes bone loss. Suppression of IFNγ levels may constitute a therapeutic approach for preventing bone loss. Copyright © 2016 Elsevier Inc. All rights reserved.
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Rodriguez-Menocal, Luis; Shareef, Shahjahan; Salgado, Marcela; Shabbir, Arsalan; Van Badiavas, Evangelos
2015-03-13
Recent evidence has shown that bone marrow cells play critical roles during the inflammatory, proliferative and remodeling phases of cutaneous wound healing. Among the bone marrow cells delivered to wounds are stem cells, which can differentiate into multiple tissue-forming cell lineages to effect, healing. Gaining insight into which lineages are most important in accelerating wound healing would be quite valuable in designing therapeutic approaches for difficult to heal wounds. In this report we compared the effect of different bone marrow preparations on established in vitro wound healing assays. The preparations examined were whole bone marrow (WBM), whole bone marrow (long term initiating/hematopoietic based) cultured cells (BMC), and bone marrow derived mesenchymal stem cells (BM-MSC). We also applied these bone marrow preparations in two murine models of radiation induced delayed wound healing to determine which had a greater effect on healing. Angiogenesis assays demonstrated that tube formation was stimulated by both WBM and BMC, with WBM having the greatest effect. Scratch wound assays showed higher fibroblast migration at 24, 48, and 72 hours in presence of WBM as compared to BM-MSC. WBM also appeared to stimulate a greater healing response than BMC and BM-MSC in a radiation induced delayed wound healing animal model. These studies promise to help elucidate the role of stem cells during repair of chronic wounds and reveal which cells present in bone marrow might contribute most to the wound healing process.
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A novel three-dimensional bone chip organ culture.
Kuttenberger, Johannes; Polska, Elzbieta; Schaefer, Birgit M
2013-07-01
The objective of this study was to develop a 3D bone chip organ culture model. We aimed to collect in vitro evidence of the ability of vital bone chips to promote new bone formation. We developed a 3D in vitro hypoxic bone chip organ culture model. Histology of the bone chips was performed before and after culture and immunohistochemistry after 3-week culture. The 3D culture supernatants were tested for the presence of pro-angiogenic growth factors, TGFβ1, GADPH, bone alkaline phosphatase, osteocalcin, osteonectin, osteopontin, bone sialoprotein and collagen type I. Histology after culture revealed bone chips in a matrix of fibrin remnants and a fibrous-appearing matter. Collagen type I- and IV-positive structures were also identified. Cells could be seen on the surface of the bone chips, with spindle-shaped cells bridging the bone chip particles. Pro-angiogenic growth factors and TGFβ1were detected in the 3D cell culture supernatants. The transcripts for osteocalcin, bone sialoprotein and collagen type I were revealed only via PCR. Our results indicate that bone chips in our 3D organ culture remain vital and may stimulate the growth of a bone-forming matrix. The use of autogenous bone chips for oral and maxillofacial bone augmentation procedures is widespread in clinical practice. The rationale for this is that if bone chips remain vital in vivo, they could provide an environment promoting new bone formation through growth factors and cells. This 3D culture method is an essential tool for investigating the behaviour of bone chips.
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Giannobile, W V; Ryan, S; Shih, M S; Su, D L; Kaplan, P L; Chan, T C
1998-02-01
Osteogenic protein-1 (OP-1) is a member of the transforming growth factor beta superfamily and is a potent modulator of osteogenesis and bone cell differentiation. This preclinical study in dogs sought to assess the effects of OP-1 on periodontal wound healing in surgically created critical size Class III furcation defects. Eighteen male beagle dogs were subjected to the creation of bilateral mandibular 5 mm osseous defects. A split-mouth design was utilized which randomly assigned opposing quadrants to control therapy (surgery alone or collagen vehicle) or 1 of 3 ascending concentrations of OP-1 in a collagen vehicle (0.75 mg OP-1/g collagen, 2.5 mg/g, or 7.5 mg/g). Thus, 9 quadrants per test group received OP-1, 9 quadrants per control group received surgery alone, and 9 quadrants received collagen vehicle alone. Test articles were delivered by a surgeon masked to the treatment, and fluorogenic bone labels were injected at specified intervals post-treatment. Eight weeks after defect creation and OP-1 delivery, tissue blocks of the mandibulae were taken for masked histomorphometric analysis to assess parameters of periodontal regeneration (e.g., bone height, bone area, new attachment formation, and percent of defect filled with new bone). Histomorphometry revealed limited evidence of osteogenesis, cementogenesis, and new attachment formation in either vehicle or surgery-alone sites. In contrast, sites treated with all 3 concentrations of OP-1 showed pronounced stimulation of osteogenesis, regenerative cementum, and new attachment formation. Lesions treated with 7.5 mg/g of OP-1 in collagen regenerated 3.9+/-1.7 mm and 6.1+/-3.4 mm2 (mean +/-S.D.) of linear bone height and bone area, respectively. Furthermore, these differences were statistically different from both control therapies for all wound healing parameters (P < 0.0001). No significant increase in tooth root ankylosis was found among the treatment groups when compared to the surgery-alone group. We conclude that OP-1 offers promise as an attractive candidate for treating severe periodontal lesions.
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Chen, Xiaohui; Zhao, Yanbing; Geng, Shinan; Miron, Richard J; Zhang, Qiao; Wu, Chengtie; Zhang, Yufeng
2015-01-01
Purpose In the present study, the fabrication of novel p(N-isopropylacrylamide-co-butyl methylacrylate) (PIB) nanogels was combined with boron-containing mesoporous bioactive glass (B-MBG) scaffolds in order to improve the mechanical properties of PIB nanogels alone. Scaffolds were tested for mechanical strength and the ability to promote new bone formation in vivo. Patients and methods To evaluate the potential of each scaffold in bone regeneration, ovariectomized rats were chosen as a study model to determine the ability of PIB nanogels to stimulate bone formation in a complicated anatomical bone defect. PIB nanogels and PIB nanogels/B-MBG composites were respectively implanted into ovariectomized rats with critical-sized femur defects following treatment periods of 2, 4, and 8 weeks post-implantation. Results Results from the present study demonstrate that PIB nanogels/B-MBG composites showed greater improvement in mechanical strength when compared to PIB nanogels alone. In vivo, hematoxylin and eosin staining revealed significantly more newly formed bone in defects containing PIB nanogels/B-MBG composite scaffolds when compared to PIB nanogels alone. Tartrate-resistant acid phosphatase-positive staining demonstrated that both scaffolds were degraded over time and bone remodeling occurred in the surrounding bone defect as early as 4 weeks post-implantation. Conclusion The results from the present study indicate that PIB nanogels are a potential bone tissue engineering biomaterial able to treat defects of irregular shapes and deformities as an injectable, thermoresponsive, biocompatible hydrogel which undergoes rapid thermal gelation once body temperature is reached. Furthermore, its combination with B-MBG scaffolds improves the mechanical properties and ability to promote new bone formation when compared to PIB nanogels alone. PMID:25653525
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Chen, Xiaohui; Zhao, Yanbing; Geng, Shinan; Miron, Richard J; Zhang, Qiao; Wu, Chengtie; Zhang, Yufeng
2015-01-01
In the present study, the fabrication of novel p(N-isopropylacrylamide-co-butyl methylacrylate) (PIB) nanogels was combined with boron-containing mesoporous bioactive glass (B-MBG) scaffolds in order to improve the mechanical properties of PIB nanogels alone. Scaffolds were tested for mechanical strength and the ability to promote new bone formation in vivo. To evaluate the potential of each scaffold in bone regeneration, ovariectomized rats were chosen as a study model to determine the ability of PIB nanogels to stimulate bone formation in a complicated anatomical bone defect. PIB nanogels and PIB nanogels/B-MBG composites were respectively implanted into ovariectomized rats with critical-sized femur defects following treatment periods of 2, 4, and 8 weeks post-implantation. Results from the present study demonstrate that PIB nanogels/B-MBG composites showed greater improvement in mechanical strength when compared to PIB nanogels alone. In vivo, hematoxylin and eosin staining revealed significantly more newly formed bone in defects containing PIB nanogels/B-MBG composite scaffolds when compared to PIB nanogels alone. Tartrate-resistant acid phosphatase-positive staining demonstrated that both scaffolds were degraded over time and bone remodeling occurred in the surrounding bone defect as early as 4 weeks post-implantation. The results from the present study indicate that PIB nanogels are a potential bone tissue engineering biomaterial able to treat defects of irregular shapes and deformities as an injectable, thermoresponsive, biocompatible hydrogel which undergoes rapid thermal gelation once body temperature is reached. Furthermore, its combination with B-MBG scaffolds improves the mechanical properties and ability to promote new bone formation when compared to PIB nanogels alone.
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Locally Produced BDNF Promotes Sclerotic Change in Alveolar Bone after Nerve Injury
Ida-Yonemochi, Hiroko; Yamada, Yurie; Yoshikawa, Hiroyuki
2017-01-01
Brain-derived neurotrophic factor (BDNF), which is released due to nerve injury, is known to promote the natural healing of injured nerves. It is often observed that damage of mandibular canal induces local sclerotic changes in alveolar bone. We reported that peripheral nerve injury promotes the local production of BDNF; therefore, it was possible to hypothesize that peripheral nerve injury affects sclerotic changes in the alveolar bone. This study aimed to evaluate the effect of BDNF on osteogenesis using in vitro osteoblast-lineage cell culture and an in vivo rat osteotomy model. MC3T3-E1 cells were cultured with BDNF and were examined for cell proliferative activity, chemotaxis and mRNA expression levels of osteoblast differentiation markers. For in vivo study, inferior alveolar nerve (IAN) injury experiments and mandibular cortical osteotomy were performed using a rat model. In the osteotomy model, exogenous BDNF was applied to bone surfaces after corticotomy of the mandible, and we morphologically analyzed the new bone formation. As a result, mRNA expression of osteoblast differentiation marker, osteocalcin, was significantly increased by BDNF, although cell proliferation and migration were not affected. In the in vivo study, osteopontin-positive new bone formation was significantly accelerated in the BDNF-grafted groups, and active bone remodeling, involving trkB-positive osteoblasts and osteocytes, continued after 28 days. In conclusion, BDNF stimulated the differentiation of MC3T3-E1 cells and it promoted new bone formation and maturation. These results suggested that local BDNF produced by peripheral nerve injury contributes to accelerating sclerotic changes in the alveolar bone. PMID:28072837
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Science and animal models of marrow stimulation for cartilage repair.
Fortier, Lisa A; Cole, Brian J; McIlwraith, C Wayne
2012-03-01
Microfracture of subchondral bone to enhance cartilage repair is a popular surgical technique used in human and animal patients. Clinical results with resolution or improvement in pain are promising and last on average for 2 to 3 years. Animal studies aimed at understanding microfracture indicate that the repair tissue continues to remodel toward chondrogenesis for at least a year, but longer term results are not available to gain insight into the mechanism of microfracture function or failure over time. Subchondral bone sclerosis and central lesional osteophyte formation following subchondral bone microfracture have been observed in animal models of microfracture, but studies do not provide any insight into the etiology of these pathologies. The continued maturation of microfracture repair tissue over time supports further investigation of microfracture or microfracture-augmented cartilage repair procedures with caution for the investigator and clinician to be observant for conditions that lead to subchondral bone sclerosis or central osteophyte formation, and what affect these boney reactions have on clinical outcome.
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Anabolic actions of Notch on mature bone
Liu, Peng; Ping, Yilin; Ma, Meng; Zhang, Demao; Liu, Connie; Zaidi, Samir; Gao, Song; Ji, Yaoting; Lou, Feng; Yu, Fanyuan; Lu, Ping; Stachnik, Agnes; Bai, Mingru; Wei, Chengguo; Zhang, Liaoran; Wang, Ke; Chen, Rong; New, Maria I.; Rowe, David W.; Yuen, Tony; Sun, Li; Zaidi, Mone
2016-01-01
Notch controls skeletogenesis, but its role in the remodeling of adult bone remains conflicting. In mature mice, the skeleton can become osteopenic or osteosclerotic depending on the time point at which Notch is activated or inactivated. Using adult EGFP reporter mice, we find that Notch expression is localized to osteocytes embedded within bone matrix. Conditional activation of Notch signaling in osteocytes triggers profound bone formation, mainly due to increased mineralization, which rescues both age-associated and ovariectomy-induced bone loss and promotes bone healing following osteotomy. In parallel, mice rendered haploinsufficient in γ-secretase presenilin-1 (Psen1), which inhibits downstream Notch activation, display almost-absent terminal osteoblast differentiation. Consistent with this finding, pharmacologic or genetic disruption of Notch or its ligand Jagged1 inhibits mineralization. We suggest that stimulation of Notch signaling in osteocytes initiates a profound, therapeutically relevant, anabolic response. PMID:27036007
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Eppley, B.L.; Connolly, D.T.; Winkelmann, T.
1991-07-01
A study was undertaken to evaluate the potential utility of basic fibroblast growth factor in the induction of angiogenesis and osseous healing in bone previously exposed to high doses of irradiation. Thirty New Zealand rabbits were evaluated by introducing basic fibroblast growth factor into irradiated mandibular resection sites either prior to or simultaneous with reconstruction by corticocancellous autografts harvested from the ilium. The fate of the free bone grafts was then evaluated at 90 days postoperatively by microangiographic, histologic, and fluorochrome bone-labeling techniques. Sequestration, necrosis, and failure to heal to recipient osseous margins was observed both clinically and histologically inmore » all nontreated irradiated graft sites as well as those receiving simultaneous angiogenic stimulation at the time of graft placement. No fluorescent activity was seen in these graft groups. In the recipient sites pretreated with basic fibroblast growth factor prior to placement of the graft, healing and reestablishment of mandibular contour occurred in nearly 50 percent of the animals. Active bone formation was evident at cortical margins adjacent to the recipient sites but was absent in the more central cancellous regions of the grafts.« less
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Biodegradable Magnesium Alloys Developed as Bone Repair Materials: A Review
Liu, Chen; Ren, Zheng; Xu, Yongdong; Pang, Song; Zhao, Xinbing
2018-01-01
Bone repair materials are rapidly becoming a hot topic in the field of biomedical materials due to being an important means of repairing human bony deficiencies and replacing hard tissue. Magnesium (Mg) alloys are potentially biocompatible, osteoconductive, and biodegradable metallic materials that can be used in bone repair due to their in situ degradation in the body, mechanical properties similar to those of bones, and ability to positively stimulate the formation of new bones. However, rapid degradation of these materials in physiological environments may lead to gas cavities, hemolysis, and osteolysis and thus, hinder their clinical orthopedic applications. This paper reviews recent work on the use of Mg alloy implants in bone repair. Research to date on alloy design, surface modification, and biological performance of Mg alloys is comprehensively summarized. Future challenges for and developments in biomedical Mg alloys for use in bone repair are also discussed. PMID:29725492
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Differential magnesium implant corrosion coat formation and contribution to bone bonding.
Rahim, Muhammad Imran; Weizbauer, Andreas; Evertz, Florian; Hoffmann, Andrea; Rohde, Manfred; Glasmacher, Birgit; Windhagen, Henning; Gross, Gerhard; Seitz, Jan-Marten; Mueller, Peter P
2017-03-01
Magnesium alloys are presently under investigation as promising biodegradable implant materials with osteoconductive properties. To study the molecular mechanisms involved, the potential contribution of soluble magnesium corrosion products to the stimulation of osteoblastic cell differentiation was examined. However, no evidence for the stimulation of osteoblast differentiation could be obtained when cultured mesenchymal precursor cells were differentiated in the presence of metallic magnesium or in cell culture medium containing elevated magnesium ion levels. Similarly, in soft tissue no bone induction by metallic magnesium or by the corrosion product magnesium hydroxide could be observed in a mouse model. Motivated by the comparatively rapid accumulation solid corrosion products physicochemical processes were examined as an alternative mechanism to explain the stimulation of bone growth by magnesium-based implants. During exposure to physiological solutions a structured corrosion coat formed on magnesium whereby the elements calcium and phosphate were enriched in the outermost layer which could play a role in the established biocompatible behavior of magnesium implants. When magnesium pins were inserted into avital bones, corrosion lead to increases in the pull out force, suggesting that the expanding corrosion layer was interlocking with the surrounding bone. Since mechanical stress is a well-established inducer of bone growth, volume increases caused by the rapid accumulation of corrosion products and the resulting force development could be a key mechanism and provide an explanation for the observed stimulatory effects of magnesium-based implants in hard tissue. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 697-709, 2017. © 2016 Wiley Periodicals, Inc.
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Lu, Shun; Wang, Jing; Ye, Jixing; Zou, Yulong; Zhu, Yunxiao; Wei, Qiang; Wang, Xin; Tang, Shengli; Liu, Hao; Fan, Jiaming; Zhang, Fugui; Farina, Evan M; Mohammed, Maryam M; Song, Dongzhe; Liao, Junyi; Huang, Jiayi; Guo, Dan; Lu, Minpeng; Liu, Feng; Liu, Jianxiang; Li, Li; Ma, Chao; Hu, Xue; Lee, Michael J; Reid, Russell R; Ameer, Guillermo A; Zhou, Dongsheng; He, Tongchuan
2016-01-01
Regenerative medicine and bone tissue engineering using mesenchymal stem cells (MSCs) hold great promise as an effective approach to bone and skeletal reconstruction. While adipose tissue harbors MSC-like progenitors, or multipotent adipose-derived cells (MADs), it is important to identify and characterize potential biological factors that can effectively induce osteogenic differentiation of MADs. To overcome the time-consuming and technically challenging process of isolating and culturing primary MADs, here we establish and characterize the reversibly immortalized mouse multipotent adipose-derived cells (iMADs). The isolated mouse primary inguinal MAD cells are reversibly immortalized via the retrovirus-mediated expression of SV40 T antigen flanked with FRT sites. The iMADs are shown to express most common MSC markers. FLP-mediated removal of SV40 T antigen effectively reduces the proliferative activity and cell survival of iMADs, indicating the immortalization is reversible. Using the highly osteogenic BMP9, we find that the iMADs are highly responsive to BMP9 stimulation, express multiple lineage regulators, and undergo osteogenic differentiation in vitro upon BMP9 stimulation. Furthermore, we demonstrate that BMP9-stimulated iMADs form robust ectopic bone with a thermoresponsive biodegradable scaffold material. Collectively, our results demonstrate that the reversibly immortalized iMADs exhibit the characteristics of multipotent MSCs and are highly responsive to BMP9-induced osteogenic differentiation. Thus, the iMADs should provide a valuable resource for the study of MAD biology, which would ultimately enable us to develop novel and efficacious strategies for MAD-based bone tissue engineering.
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Neuronal hypothalamic regulation of body metabolism and bone density is galanin dependent.
Idelevich, Anna; Sato, Kazusa; Nagano, Kenichi; Rowe, Glenn; Gori, Francesca; Baron, Roland
2018-06-01
In the brain, the ventral hypothalamus (VHT) regulates energy and bone metabolism. Whether this regulation uses the same or different neuronal circuits is unknown. Alteration of AP1 signaling in the VHT increases energy expenditure, glucose utilization, and bone density, yet the specific neurons responsible for each or all of these phenotypes are not identified. Using neuron-specific, genetically targeted AP1 alterations as a tool in adult mice, we found that agouti-related peptide-expressing (AgRP-expressing) or proopiomelanocortin-expressing (POMC-expressing) neurons, predominantly present in the arcuate nucleus (ARC) within the VHT, stimulate whole-body energy expenditure, glucose utilization, and bone formation and density, although their effects on bone resorption differed. In contrast, AP1 alterations in steroidogenic factor 1-expressing (SF1-expressing) neurons, present in the ventromedial hypothalamus (VMH), increase energy but decrease bone density, suggesting that these effects are independent. Altered AP1 signaling also increased the level of the neuromediator galanin in the hypothalamus. Global galanin deletion (VHT galanin silencing using shRNA) or pharmacological galanin receptor blockade counteracted the observed effects on energy and bone. Thus, AP1 antagonism reveals that AgRP- and POMC-expressing neurons can stimulate body metabolism and increase bone density, with galanin acting as a central downstream effector. The results obtained with SF1-expressing neurons, however, indicate that bone homeostasis is not always dictated by the global energy status, and vice versa.
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Lei, Tao; Li, Feijiang; Liang, Zhuowen; Tang, Chi; Xie, Kangning; Wang, Pan; Dong, Xu; Shan, Shuai; Liu, Juan; Xu, Qiaoling; Luo, Erping; Shen, Guanghao
2017-04-03
Electromagnetic fields (EMF) was considered as a non-invasive modality for treatment of osteoporosis while the effects were diverse with EMF parameters in time domain. In present study, we extended analysis of EMF characteristics from time domain to frequency domain, aiming to investigate effects of four kinds of EMF (LP (1-100 Hz), BP (100-3,000 Hz), HP (3,000-50,000 Hz) and AP (1-50,000 Hz)) on ovariectomized (OVX) osteoporosis (OP) in mice. Forty-eight 3-month-old female BALB/c mice were equally assigned to Sham, OVX, OVX + LP, OVX + BP, OVX + HP and OVX + AP groups (n = 8). After 8-week exposure (3 h/day), LP and BP significantly increased serum bone formation markers and osteogenesis-related gene expressions compared with OVX. Bedsides, LP and BP also slightly increased bone resorption activity compared with OVX, evidenced by increased RANKL/OPG ratio. HP sharply decreased serum bone formation and resporption markers and osteogenesis and osteoclastogenesis related gene expressions compared with OVX. AP had accumulative effects of LP, BP and HP, which significantly increased bone formation and decreased bone resporption activity compared with OVX. As a result, LP, BP and HP exposure did not later deterioration of bone mass, microarchitecture and mechanical strength in OVX mice with OP. However, AP stimulation attenuated OVX-induced bone loss.
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Spector, Tim D; Calomme, Mario R; Anderson, Simon H; Clement, Gail; Bevan, Liisa; Demeester, Nathalie; Swaminathan, Rami; Jugdaohsingh, Ravin; Berghe, Dirk A Vanden; Powell, Jonathan J
2008-01-01
Background Mounting evidence supports a physiological role for silicon (Si) as orthosilicic acid (OSA, Si(OH)4) in bone formation. The effect of oral choline-stabilized orthosilicic acid (ch-OSA) on markers of bone turnover and bone mineral density (BMD) was investigated in a double-blind placebo-controlled trial. Methods Over 12-months, 136 women out of 184 randomized (T-score spine < -1.5) completed the study and received, daily, 1000 mg Ca and 20 μg cholecalciferol (Vit D3) and three different ch-OSA doses (3, 6 and 12 mg Si) or placebo. Bone formation markers in serum and urinary resorption markers were measured at baseline, and after 6 and 12 months. Femoral and lumbar BMD were measured at baseline and after 12 months by DEXA. Results Overall, there was a trend for ch-OSA to confer some additional benefit to Ca and Vit D3 treatment, especially for markers of bone formation, but only the marker for type I collagen formation (PINP) was significant at 12 months for the 6 and 12 mg Si dose (vs. placebo) without a clear dose response effect. A trend for a dose-corresponding increase was observed in the bone resorption marker, collagen type I C-terminal telopeptide (CTX-I). Lumbar spine BMD did not change significantly. Post-hoc subgroup analysis (baseline T-score femur < -1) however was significant for the 6 mg dose at the femoral neck (T-test). There were no ch-OSA related adverse events observed and biochemical safety parameters remained within the normal range. Conclusion Combined therapy of ch-OSA and Ca/Vit D3 had a potential beneficial effect on bone collagen compared to Ca/Vit D3 alone which suggests that this treatment is of potential use in osteoporosis. NTR 1029 PMID:18547426
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Wang, Chuandong; Shan, Shengzhou; Wang, Chenglong; Wang, Jing; Li, Jiao; Hu, Guoli; Dai, Kerong; Li, Qingfeng; Zhang, Xiaoling
2017-03-15
Mechanical unloading leads to bone loss and disuse osteoporosis partly due to impaired osteoblastogenesis of bone marrow stromal cells (BMSCs). However, the underlying molecular mechanisms of this phenomenon are not fully understood. In this study, we demonstrated that cyclic mechanical stretch (CMS) promotes osteoblastogenesis of BMSCs both in vivo and in vitro. Besides, we found that Hedgehog (Hh) signaling pathway was activated in this process. Inhibition of which by either knockdown of Sonic hedgehog (Shh) or treating BMSCs with Hh inhibitors attenuated the osteogenic effect of CMS on BMSCs, suggesting that Hh signaling pathway acts as an endogenous mediator of mechanical stimuli on BMSCs. Furthermore, we demonstrated that Shh expression level was regulated by DNA methylation mechanism. Chromatin Immunoprecipitation (ChIP) assay showed that DNA methyltransferase 3b (Dnmt3b) binds to Shh gene promoter, leading to DNA hypermethylation in mechanical unloading BMSCs. However, mechanical stimulation down-regulates the protein level of Dnmt3b, results in DNA demethylation and Shh expression. More importantly, we found that inhibition of Dnmt3b partly rescued bone loss in HU mice by mechanical unloading. Our results demonstrate, for the first time, that mechanical stimulation regulates osteoblastic genes expression via direct regulation of Dnmt3b, and the therapeutic inhibition of Dnmt3b may be an efficient strategy for enhancing bone formation under mechanical unloading. Copyright © 2017 Elsevier Inc. All rights reserved.
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Tang, Wanjin; Li, Yang; Osimiri, Lindsey; Zhang, Chi
2011-09-23
Osterix (Osx) is an osteoblast-specific transcription factor essential for osteoblast differentiation and bone formation. Osx knock-out mice lack bone completely. Satb2 is critical for osteoblast differentiation as a special AT-rich binding transcription factor. It is not known how Satb2 is transcriptionally regulated during bone formation. In this study, quantitative real-time RT-PCR results demonstrated that Satb2 was down-regulated in Osx-null calvaria. In stable C2C12 mesenchymal cells using the tetracycline (Tet)-Off system, overexpression of Osx stimulated Satb2 expression. Moreover, inhibition of Osx by siRNA led to repression of Satb2 expression in osteoblasts. These results suggest that Osx controls Satb2 expression. Transient transfection assay showed that Osx activated 1kb Satb2 promoter reporter activity in a dose-dependent manner. To define the region of Satb2 promoter responsive to Osx activation, a series of deletion mutants of Satb2 constructs were made, and the minimal region was narrowed down to the proximal 130 bp of the Satb2 promoter. Further point mutation studies found that two GC-rich region mutations disrupted the Satb2 130bp promoter activation by Osx, suggesting that these GC-rich binding sites were responsible for Satb2 activation by Osx. Gel shift assay showed that Osx bound to the Satb2 promoter sequence directly. ChIP assays indicated that endogenous Osx associated with the native Satb2 promoter in osteoblasts. Importantly, Satb2 siRNA significantly inhibited Osx-induced osteoblast marker gene expressions. Taken together, our findings indicate that Osx is an upstream regulator of Satb2 during bone formation. This reveals a new additional link of the transcriptional regulation mechanism that Osx controls bone formation.
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Santos-Oliveira, Ralph; Lima-Ribeiro, Maria Helena Madruga; Carneiro-Leão, Ana Maria dos Anjos; Cruz, Adriana Ferreira; de Santana, Mauricélia Firmino; Cavalcanti, Carmelita de Lima Bezerra; de Pontes Filho, Nicodemos Teles; Coelho, Luana Cassandra Breitenbach Barroso; dos Santos Correia, Maria Tereza
2013-01-01
Context: Regeneration corresponds to the replacement of damaged cells with ones that have the same morphology and function. For experimental evaluation of materials that may favor the process of bone healing, defects are created with dimensions that prevent spontaneous regeneration. For the development and use of new drugs, it is necessary to study its effects in vitro, which depends on the formulation, concentration, and rate of irradiation in vivo and the route and frequency of administration; thus, it is possible to characterize the physiological and molecular mechanisms involved in the response and cellular effects. Objective: The objective of this study was to assess the effect of Cramoll-1,4 on the process of bone repair. Materials and Methods: A formulation of biopharmaceutical lectin Cramoll-1,4 at a concentration of 300 mg/100 mL was applied in a single application via gamma radiation and its effect on the process of bone repair in rats was assessed. Results: Histologically, it was observed that the bone defect is coated by loose connective tissue rich in fibroblasts, providing a range similar to the thick bone original and competing with site of new bone formation. This prevented direct contact between the formulation and experimental bone tissue, as, despite its proven effectiveness in experiments on the repair of skin lesions, the formulation used did not promote bone stimulation that would have promoted the tissue repair process. Conclusion: Because of the direct interference of loose tissue repair that prevented direct contact of the implant with the bone interface, the formulation did not promote bone stimulation. PMID:24083142
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Nakayama, Youhei; Nakajima, Yu; Kato, Naoko; Takai, Hideki; Kim, Dong-Soon; Arai, Masato; Mezawa, Masaru; Araki, Shouta; Sodek, Jaro; Ogata, Yorimasa
2006-08-01
Insulin-like growth factor-I (IGF-I) promotes bone formation by stimulating proliferation and differentiation of osteoblasts. Bone sialoprotein (BSP), is thought to function in the initial mineralization of bone, is selectively expressed by differentiated osteoblast. To determine the molecular mechanism of IGF-I regulation of osteogenesis, we analyzed the effects of IGF-I on the expression of BSP in osteoblast-like Saos2 and in rat stromal bone marrow (RBMC-D8) cells. IGF-I (50 ng/ml) increased BSP mRNA levels at 12 h in Saos2 cells. In RBMC-D8 cells, IGF-I increased BSP mRNA levels at 3 h. From transient transfection assays, a twofold increase in transcription by IGF-I was observed at 12 h in pLUC3 construct that included the promoter sequence from -116 to +60. Effect of IGF-I was abrogated by 2-bp mutations in either the FGF2 response element (FRE) or homeodomain protein-binding site (HOX). Gel shift analyses showed that IGF-I increased binding of nuclear proteins to the FRE and HOX elements. Notably, the HOX-protein complex was supershifted by Smad1 antibody, while the FRE-protein complex was shifted by Smad1 and Cbfa1 antibodies. Dlx2 and Dlx5 antibodies disrupted the formation of the FRE- and HOX-protein complexes. The IGF-I effects on the formation of FRE-protein complexes were abolished by tyrosine kinase inhibitor herbimycin A (HA), PI3-kinase/Akt inhibitor LY249002, and MAP kinase kinase inhibitor U0126, while IGF-I effects on HOX-protein complexes were abolished by HA and LY249002. These studies demonstrate that IGF-I stimulates BSP transcription by targeting the FRE and HOX elements in the proximal promoter of BSP gene.
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Shin, Hyun-Jae; Lee, Ha-Yan; Cho, Hye-Young; Park, Yun-Jin; Moon, Hyung-Hoon; Lee, Sung-Hwan; Lee, Sung-Ki; Kim, Myung-Ki
2014-04-01
Menopause is characterized by rapid decreases in bone mineral density, aerobic fitness, muscle strength, and balance. In the present study, we investigated the effects of new sports tennis type exercise on aerobic capacity, follicle stimulating hormone (FSH) and N-terminal telopeptide (NTX) in the postmenopausal women. Subjects were consisted of 20 postmenopausal women, who had not menstruated for at least 1 yr and had follicle-stimulating hormone levels > 35 mIU/L, estradiol levels< 40 pg/mL. The subjects were randomly divided into two groups: control group (n= 10), new sports tennis type exercise group (n= 10). New sports tennis type exercise was consisted of warm up (10 min), new sports tennis type exercise (40 min), cool down (10 min) 3 days a per week for 12 weeks. The aerobic capacities were increased by 12 weeks new sports tennis type exercise. New sports tennis type exercise significantly increased FSH and NTx levels, indicating biochemical markers of bone formation and resorption. These findings indicate that 12 weeks of new sports tennis type exercise can be effective in prevention of bone loss and enhancement of aerobic capacity in postmenopausal women.
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Functions of vasopressin and oxytocin in bone mass regulation
Sun, Li; Tamma, Roberto; Yuen, Tony; Colaianni, Graziana; Ji, Yaoting; Cuscito, Concetta; Bailey, Jack; Dhawan, Samarth; Lu, Ping; Calvano, Cosima D.; Zhu, Ling-Ling; Zambonin, Carlo G.; Di Benedetto, Adriana; Stachnik, Agnes; Liu, Peng; Grano, Maria; Colucci, Silvia; Davies, Terry F.; New, Maria I.; Zallone, Alberta; Zaidi, Mone
2016-01-01
Prior studies show that oxytocin (Oxt) and vasopressin (Avp) have opposing actions on the skeleton exerted through high-affinity G protein-coupled receptors. We explored whether Avp and Oxtr can share their receptors in the regulation of bone formation by osteoblasts. We show that the Avp receptor 1α (Avpr1α) and the Oxt receptor (Oxtr) have opposing effects on bone mass: Oxtr−/− mice have osteopenia, and Avpr1α−/− mice display a high bone mass phenotype. More notably, this high bone mass phenotype is reversed by the deletion of Oxtr in Oxtr−/−:Avpr1α−/− double-mutant mice. However, although Oxtr is not indispensable for Avp action in inhibiting osteoblastogenesis and gene expression, Avp-stimulated gene expression is inhibited when the Oxtr is deleted in Avpr1α−/− cells. In contrast, Oxt does not interact with Avprs in vivo in a model of lactation-induced bone loss in which Oxt levels are high. Immunofluorescence microscopy of isolated nucleoplasts and Western blotting and MALDI-TOF of nuclear extracts show that Avp triggers Avpr1α localization to the nucleus. Finally, a specific Avpr2 inhibitor, tolvaptan, does not affect bone formation or bone mass, suggesting that Avpr2, which primarily functions in the kidney, does not have a significant role in bone remodeling. PMID:26699482
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Protein kinase Cα (PKCα) regulates bone architecture and osteoblast activity.
Galea, Gabriel L; Meakin, Lee B; Williams, Christopher M; Hulin-Curtis, Sarah L; Lanyon, Lance E; Poole, Alastair W; Price, Joanna S
2014-09-12
Bones' strength is achieved and maintained through adaptation to load bearing. The role of the protein kinase PKCα in this process has not been previously reported. However, we observed a phenotype in the long bones of Prkca(-/-) female but not male mice, in which bone tissue progressively invades the medullary cavity in the mid-diaphysis. This bone deposition progresses with age and is prevented by disuse but unaffected by ovariectomy. Castration of male Prkca(-/-) but not WT mice results in the formation of small amounts of intramedullary bone. Osteoblast differentiation markers and Wnt target gene expression were up-regulated in osteoblast-like cells derived from cortical bone of female Prkca(-/-) mice compared with WT. Additionally, although osteoblastic cells derived from WT proliferate following exposure to estradiol or mechanical strain, those from Prkca(-/-) mice do not. Female Prkca(-/-) mice develop splenomegaly and reduced marrow GBA1 expression reminiscent of Gaucher disease, in which PKC involvement has been suggested previously. From these data, we infer that in female mice, PKCα normally serves to prevent endosteal bone formation stimulated by load bearing. This phenotype appears to be suppressed by testicular hormones in male Prkca(-/-) mice. Within osteoblastic cells, PKCα enhances proliferation and suppresses differentiation, and this regulation involves the Wnt pathway. These findings implicate PKCα as a target gene for therapeutic approaches in low bone mass conditions. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.
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Feng, Yuxu; Zhou, Min; Zhang, Qunhu; Liu, Huan; Xu, Yong; Shu, Lei; Zhang, Jue; Miao, Dengshun; Ren, Yongxin
2015-03-28
In the present study, we investigated whether high dietary Ca and exogenous parathyroid hormone 1-34 fragments (PTH 1-34) have synergistic effects on bone formation in adult mice, and explored the related mechanisms. Adult male mice were fed a normal diet, a high-Ca diet, a PTH-treated diet, or a high-Ca diet combined with subcutaneously injected PTH 1-34 (80 μg/kg per d) for 4 weeks. Bone mineral density, trabecular bone volume, osteoblast number, alkaline phosphatase (ALP)- and type I collagen-positive areas, and the expression levels of osteoblastic bone formation-related genes and proteins were increased significantly in mice fed the high-Ca diet, the PTH-treated diet, and, even more dramatically, the high-Ca diet combined with PTH. Osteoclast number and surface and the ratio of receptor activator for nuclear factor-κB ligand (RANKL):osteoprotegerin (OPG) were decreased in the high-Ca diet treatment group, increased in the PTH treatment group, but not in the combined treatment group. Furthermore, third-passage osteoblasts were treated with high Ca (5 mM), PTH 1-34 (10⁻⁸ M) or high Ca combined with PTH 1-34. Osteoblast viability and ALP activity were increased in either the high Ca-treated or PTH-treated cultures and, even more dramatically, in the cultures treated with high Ca plus PTH, with consistent up-regulation of the expression levels of osteoblast proliferation and differentiation-related genes and proteins. These results indicate that dietary Ca and PTH play synergistic roles in promoting osteoblastic bone formation by stimulating osteoblast proliferation and differentiation.
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BMP-7 Preserves Surface Integrity of Degradable-ceramic Cranioplasty in a Göttingen Minipig Model
Schulz, Peter; Klünter, Tim; Deisinger, Ulrike; Diez, Claudius; Waiss, Waltraud; Kirschneck, Christian; Reichert, Torsten E.; Detsch, Rainer
2017-01-01
Background: The aim of the study was to evaluate the integrity of a craniotomy grafted site in a minipig model using different highly porous calcium phosphate ceramic scaffolds either loaded or nonloaded with bone morphogenetic protein-7 (BMP-7). Methods: Four craniotomies with a diameter of 15 mm (critical-size defect) were grafted with different highly porous (92–94 vol%) calcium phosphate ceramics [hydroxyapatite (HA), tricalcium phosphate (TCP), and biphasic calcium phosphate (BCP; a mixture of HA and TCP)] in 10 Göttingen minipigs: (a) group I (n = 5): HA versus BCP; (b) group II (n = 5): TCP versus BCP. One scaffold of each composition was supplied with 250 μg of BMP-7. In vivo computed tomography scan and fluorochrome bone labeling were performed. Specimens were evaluated 14 weeks after surgery by environmental scanning electron microscopy, fluorescence microscopy, and Giemsa staining histology. Results: BMP-7 significantly enhanced bone formation in TCP (P = 0.047). Slightly enhanced bone formation was observed in BCP (P = 0.059) but not in HA implants. BMP-7 enhanced ceramic degradation in TCP (P = 0.05) and BCP (P = 0.05) implants but not in HA implants. Surface integrity of grafted site was observed in all BMP-7-loaded implants after successful creeping substitution by the newly formed bone. In 9 of 10 HA implants without BMP-7, partial collapse of the implant site was observed. All TCP implants without BMP-7 collapsed. Fluorescent labeling showed bone formation at week 1 in BMP-7-stimulated implants. Conclusions: BMP-7 supports bone formation, ceramic degradation, implant integration, and surface integrity of the grafted site. PMID:28458969
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In vivo study of magnesium plate and screw degradation and bone fracture healing.
Chaya, Amy; Yoshizawa, Sayuri; Verdelis, Kostas; Myers, Nicole; Costello, Bernard J; Chou, Da-Tren; Pal, Siladitya; Maiti, Spandan; Kumta, Prashant N; Sfeir, Charles
2015-05-01
Each year, millions of Americans suffer bone fractures, often requiring internal fixation. Current devices, like plates and screws, are made with permanent metals or resorbable polymers. Permanent metals provide strength and biocompatibility, but cause long-term complications and may require removal. Resorbable polymers reduce long-term complications, but are unsuitable for many load-bearing applications. To mitigate complications, degradable magnesium (Mg) alloys are being developed for craniofacial and orthopedic applications. Their combination of strength and degradation make them ideal for bone fixation. Previously, we conducted a pilot study comparing Mg and titanium devices with a rabbit ulna fracture model. We observed Mg device degradation, with uninhibited healing. Interestingly, we observed bone formation around degrading Mg, but not titanium, devices. These results highlighted the potential for these fixation devices. To better assess their efficacy, we conducted a more thorough study assessing 99.9% Mg devices in a similar rabbit ulna fracture model. Device degradation, fracture healing, and bone formation were evaluated using microcomputed tomography, histology and biomechanical tests. We observed device degradation throughout, and calculated a corrosion rate of 0.40±0.04mm/year after 8 weeks. In addition, we observed fracture healing by 8 weeks, and maturation after 16 weeks. In accordance with our pilot study, we observed bone formation surrounding Mg devices, with complete overgrowth by 16 weeks. Bend tests revealed no difference in flexural load of healed ulnae with Mg devices compared to intact ulnae. These data suggest that Mg devices provide stabilization to facilitate healing, while degrading and stimulating new bone formation. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
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Baas, Jorgen; Vestermark, Marianne; Jensen, Thomas; Bechtold, Joan; Soballe, Kjeld; Jakobsen, Thomas
2017-04-01
Bone allograft is used in total joint arthroplasties in order to enhance implant fixation. BMPs are known to stimulate new bone formation within allograft, but also known to accelerate graft resorption. Bisphosphonates are strong inhibitor of bone resorption. The aim of this study was to investigate whether the bisphosphonate zoledronate was able to counteract the accelerated graft resorption without interfering with the BMP induced bone formation. In the present study the two drugs alone and in combination were studied in our canine model of impaction bone grafting. We included 10 dogs in this study. Cancellous allograft bone grafts were soaked in either saline or zoledronate solution (0.005mg/mL) and then vehicle or BMP2 (0.15mg rhBMP2) was added. This produced four treatment groups: A) control, B) BMP2, C) zoledronate and D) BMP2+zoledronate. The allograft treated with A, B, C or D was impacted into a circumferential defect of 2.5mm around HA-coated porous Ti implants. Each dog received all four treatment groups with two implants in the distal part of each femur. The group with allograft soaked in zoledronate (C) showed better biomechanical fixation than all other groups (p<0.05). It had less allograft resorption compared to all other groups (p<0.005) without any statistically significant change in new bone formation. The addition of BMP2 to the allograft did not increase new bone formation significantly, but did accelerate allograft resorption. This was also the case where the allograft was treated with BMP2 and zoledronate in combination (D). This caused a decrease in mechanical implant fixation in both these groups compared to the control group, however only statistically significant for the BMP2 group compared to control. The study shows that topical zoledronate can be a valuable tool for augmenting bone grafts when administered optimally. The use of BMP2 in bone grafting procedures seems associated with a high risk of bone resorption and mechanical weakening. Copyright © 2017 Elsevier Inc. All rights reserved.
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Baas, Jorgen; Vestermark, Marianne; Jensen, Thomas; Bechtold, Joan; Soballe, Kjeld; Jakobsen, Thomas
2017-01-01
Bone allograft is used in total joint artroplasties in order to enhance implant fixation. BMPs are known to stimulate new bone formation within allograft, but also known to accelerate graft resorption. Bisphosphonates are strong inhibitor of bone resorption. The aim of this study was to investigate whether the bisphosphonate zoledronate was able to counteract the accelerated graft resorption without interfering with the BMP induced bone formation. In the present study the two drugs alone and in combination were studied in our canine model of impaction bone grafting. We included 10 dogs in this study. Cancellous allograft bone grafts were soaked in either saline or zoledronate solution (0.005 mg/mL) and then vehicle or BMP2 (0.15 mg rhBMP2) was added. This produced four treatment groups: A) control B) BMP2 C) zoledronate and D) BMP2+ zoledronate. The allograft treated with A,B,C or D was impacted into a circumferential defect of 2.5 mm around HA-coated porous Ti implants. Each dog received all four treatment groups with two implants in the distal part of each femur. The group with allograft soaked in zoledronate (C) showed better biomechanical fixation than all other groups (p<0.05). It had less allograft resorption compared to all other groups (p<0.005) without any statistically significant change in new bone formation. The addition of BMP2 to the allograft did not increase new bone formation significantly, but did accelerate allograft resorption. This was also the case where the allograft was treated with BMP2 and zoledronate in combination (D). This caused a decrease in mechanical implant fixation in both these groups compared to the control group, however only statistically significant for the BMP2 group compared to control. The study shows that topical zoledronate can be a valuable tool for augmenting bone grafts when administered optimally. The use of BMP2 in bone grafting procedures seems associated with a high risk of bone resorption and mechanical weakening. PMID:28082076
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Skeletal unloading induces resistance to insulin-like growth factor I
NASA Technical Reports Server (NTRS)
Bikle, D. D.; Harris, J.; Halloran, B. P.; Morey-Holton, E. R.
1994-01-01
In previous studies with a hindlimb elevation model, we demonstrated that skeletal unloading transiently inhibits bone formation. This effect is limited to the unloaded bones (the normally loaded humerus does not cease growing), suggesting that local factors are of prime importance. IGF-I is one such factor; it is produced in bone and stimulates bone formation. To determine the impact of skeletal unloading on IGF-I production and function, we assessed the mRNA levels of IGF-I and its receptor (IGF-IR) in the proximal tibia and distal femur of growing rats during 2 weeks of hindlimb elevation. The mRNA levels for IGF-I and IGF-IR rose during hindlimb elevation, returning toward control values during recovery. This was accompanied by a 77% increase in IGF-I levels in the bone, peaking at day 10 of unloading. Changes in IGF binding protein levels were not observed. Infusion of IGF-I (200 micrograms/day) during 1 week of hindlimb elevation doubled the increase in bone mass of the control animals but failed to reverse the cessation of bone growth in the hindlimb-elevated animals. We conclude that skeletal unloading induces resistance to IGF-I, which may result secondarily in increased local production of IGF-I.
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NASA Technical Reports Server (NTRS)
Judex, Stefan; Donahue, Leah-Rae; Rubin, Clinton
2002-01-01
The structure of the adult skeleton is determined, in large part, by its genome. Whether genetic variations may influence the effectiveness of interventions to combat skeletal diseases remains unknown. The differential response of trabecular bone to an anabolic (low-level mechanical vibration) and a catabolic (disuse) mechanical stimulus were evaluated in three strains of adult mice. In low bone-mineral-density C57BL/6J mice, the low-level mechanical signal caused significantly larger bone formation rates (BFR) in the proximal tibia, but the removal of functional weight bearing did not significantly alter BFR. In mid-density BALB/cByJ mice, mechanical stimulation also increased BFR, whereas disuse significantly decreased BFR. In contrast, neither anabolic nor catabolic mechanical signals influenced any index of bone formation in high-density C3H/HeJ mice. Together, data from this study indicate that the sensitivity of trabecular tissue to both anabolic and catabolic stimuli is influenced by the genome. Extrapolated to humans, these results may explain in part why prophylaxes for low bone mass are not universally effective, yet also indicate that there may be a genotypic indication of people who are at reduced risk of suffering from bone loss.
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Zhang, Ziyu; Yuan, Lang; Lee, Peter D; Jones, Eric; Jones, Julian R
2014-01-01
Bone augmentation implants are porous to allow cellular growth, bone formation and fixation. However, the design of the pores is currently based on simple empirical rules, such as minimum pore and interconnects sizes. We present a three-dimensional (3D) transient model of cellular growth based on the Navier–Stokes equations that simulates the body fluid flow and stimulation of bone precursor cellular growth, attachment, and proliferation as a function of local flow shear stress. The model's effectiveness is demonstrated for two additive manufactured (AM) titanium scaffold architectures. The results demonstrate that there is a complex interaction of flow rate and strut architecture, resulting in partially randomized structures having a preferential impact on stimulating cell migration in 3D porous structures for higher flow rates. This novel result demonstrates the potential new insights that can be gained via the modeling tool developed, and how the model can be used to perform what-if simulations to design AM structures to specific functional requirements. PMID:24664988
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Matsumoto, Kenichi; Shimo, Tsuyoshi; Kurio, Naito; Okui, Tatsuo; Ibaragi, Soichiro; Kunisada, Yuki; Obata, Kyoichi; Masui, Masanori; Pai, Pang; Horikiri, Yuu; Yamanaka, Nobuyuki; Takigawa, Masaharu; Sasaki, Akira
2018-06-01
Low-intensity pulsed ultrasound (LIPUS) has been used as an adjunct to fracture healing therapies, but the mechanisms underlying its action are not known. We reported that sonic hedgehog (SHH) signaling was activated in osteoblasts at the dynamic remodeling site of a bone fracture. Mechanical stimulation is a crucial factor in bone remodeling, and it is related to the primary cilia as a sensor of hedgehog signaling. Here we observed that LIPUS promoted callus formation in accord with Gli2-positive cells after 14 days at the mouse femur fractured site compared with a control group. An immunofluorescence analysis showed that the numbers of primary cilia and cilia/osterix double-positive osteoblasts were increased at the fracture site by LIPUS. LIPUS stimulated not only the number and the length of primary cilia, but also the levels of ciliated protein, Ift88 mRNA, and SHH, Gli1, and Gli2 in MC3T3-E1 cells. Further experiments revealed that LIPUS stimulated osteogenic differentiation in the presence of smoothened agonist (SAG) treatment. These results indicate that LIPUS stimulates osteogenic differentiation and the maturation of osteoblasts by a primary cilium-mediated activation of hedgehog signaling. © 2017 Wiley Periodicals, Inc.
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New management options for osteoporosis with emphasis on SERMs.
McClung, M R
2015-01-01
Albright was the first of many to show that loss of bone mass due to estrogen deficiency is an important part of the pathogenesis of postmenopausal osteoporosis. This led to the use of estrogen therapy which was shown to prevent bone loss at menopause and to reduce the risk of important fragility fractures. Selective estrogen receptor modulators (SERMs), with salutary estrogen-like skeletal effects and with protection from breast cancer, have important roles in the management of young postmenopausal women. New members of the SERM family may approach the effectiveness of estrogen in preventing bone loss and reducing fracture risk. When combined with estrogen, new SERMs prevent endometrial hyperplasia, and that combination reduces menopausal symptoms and prevents bone loss. Drugs that reduce bone turnover or stimulate bone formation by non-estrogen pathways have also been developed to treat osteoporosis. Emerging therapies, with unique mechanisms of action, may provide improved efficacy in treating women who already have osteoporosis.
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Emerging Therapeutic Opportunities for Skeletal Restoration
Kawai, Masanobu; Mödder, Ulrike I.; Khosla, Sundeep; Rosen, Clifford J
2011-01-01
Preface Osteoporosis, a syndrome characterized by thin bones and fractures, has become more prevalent in both women and men. Established therapies for this disorder consist primarily of drugs that prevent bone loss, such as the bisphosphonates and selective estrogen receptor modulators. Although these drugs have been shown to reduce fractures in randomized trials, there is an urgent need for treatments that could lower fracture risk further without additional adverse effects. The introduction of parathyroid hormone (teriparatide), which significantly increases bone mineral density, albeit for a relatively short duration, raised expectations that drugs which stimulate bone formation might cure osteoporosis. After outlining current approaches to treating osteoporosis, this review focuses on emerging therapeutic opportunities for osteoporosis that are based on recent insights into skeletal physiology. Such novel strategies offer promise for not only reducing age-related bone loss and the associated risk of fractures, but restoring bone mineral density to healthy levels. PMID:21283108
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Castillo-Dalí, G; Castillo-Oyagüe, R; Batista-Cruzado, A; López-Santos, C; Rodríguez-González-Elipe, A; Saffar, J-L; Lynch, C-D; Gutiérrez-Pérez, J-L; Torres-Lagares, D
2017-03-01
The use of cold plasmas may improve the surface roughness of poly(lactic-co-glycolic) acid (PLGA) membranes, which may stimulate the adhesion of osteogenic mediators and cells, thus accelerating the biodegradation of the barriers. Moreover, the incorporation of metallic-oxide particles to the surface of these membranes may enhance their osteoinductive capacity. Therefore, the aim of this paper was to evaluate the reliability of a new PLGA membrane after being treated with oxygen plasma (PO2) plus silicon dioxide (SiO2) layers for guided bone regeneration (GBR) processes. Circumferential bone defects (diameter: 11 mm; depth: 3 mm) were created on the top of eight experimentation rabbits' skulls and were randomly covered with: (1) PLGA membranes (control), or (2) PLGA/PO2/SiO2 barriers. The animals were euthanized two months afterwards. A micromorphologic study was then performed using ROI (region of interest) colour analysis. Percentage of new bone formation, length of mineralised bone, concentration of osteoclasts, and intensity of ostheosynthetic activity were assessed and compared with those of the original bone tissue. The Kruskal-Wallis test was applied for between-group com Asignificance level of a=0.05 was considered. The PLGA/PO2/SiO2 membranes achieved the significantly highest new bone formation, length of mineralised bone, concentration of osteoclasts, and ostheosynthetic activity. The percentage of regenerated bone supplied by the new membranes was similar to that of the original bone tissue. Unlike what happened in the control group, PLGA/PO2/SiO2 membranes predominantly showed bone layers in advanced stages of formation. The addition of SiO2 layers to PLGA membranes pre-treated with PO2 improves their bone-regeneration potential. Although further research is necessary to corroborate these conclusions in humans, this could be a promising strategy to rebuild the bone architecture prior to rehabilitate edentulous areas.
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Lymphatic Endothelial Cells Produce M-CSF, Causing Massive Bone Loss in Mice.
Wang, Wensheng; Wang, Hua; Zhou, Xichao; Li, Xing; Sun, Wen; Dellinger, Michael; Boyce, Brendan F; Xing, Lianping
2017-05-01
Gorham-Stout disease (GSD) is a rare bone disorder characterized by aggressive osteolysis associated with lymphatic vessel invasion within bone marrow cavities. The etiology of GSD is not known, and there is no effective therapy or animal model for the disease. Here, we investigated if lymphatic endothelial cells (LECs) affect osteoclasts (OCs) to cause a GSD osteolytic phenotype in mice. We examined the effect of a mouse LEC line on osteoclastogenesis in co-cultures. LECs significantly increased receptor activator of NF-κB ligand (RANKL)-mediated OC formation and bone resorption. LECs expressed high levels of macrophage colony-stimulating factor (M-CSF), but not RANKL, interleukin-6 (IL-6), and tumor necrosis factor (TNF). LEC-mediated OC formation and bone resorption were blocked by an M-CSF neutralizing antibody or Ki20227, an inhibitor of the M-CSF receptor, c-Fms. We injected LECs into the tibias of wild-type (WT) mice and observed massive osteolysis on X-ray and micro-CT scans. Histology showed that LEC-injected tibias had significant trabecular and cortical bone loss and increased OC numbers. M-CSF protein levels were significantly higher in serum and bone marrow plasma of mice given intra-tibial LEC injections. Immunofluorescence staining showed extensive replacement of bone and marrow by podoplanin+ LECs. Treatment of LEC-injected mice with Ki20227 significantly decreased tibial bone destruction. In addition, lymphatic vessels in a GSD bone sample were stained positively for M-CSF. Thus, LECs cause bone destruction in vivo in mice by secreting M-CSF, which promotes OC formation and activation. Blocking M-CSF signaling may represent a new therapeutic approach for treatment of patients with GSD. Furthermore, tibial injection of LECs is a useful mouse model to study GSD. © 2017 American Society for Bone and Mineral Research. © 2017 American Society for Bone and Mineral Research.
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USDA-ARS?s Scientific Manuscript database
A blueberry (BB) supplemented diet previously has been shown to significantly stimulate bone formation in rapidly growing male and female rodents. Phenolic acids (PAs) are metabolites derived from polyphenols found in fruits and vegetables as a result of the actions of gut bacteria, and they were fo...
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Wilhelm, Birgit; Kann, Peter Herbert
2004-10-15
Subnormal bone mineral density (BMD) and increased fracture risk are described in patients with growth hormone deficiency (GHD). Growth hormone (GH) has been reported to have beneficial effects on bone in GHD. The aim of this study was to investigate the long-term effects of GH replacement therapy on bone metabolism, BMD, and bone quality in patients with GHD. 20 adult patients with GHD (eleven male, nine female, mean age 42.5 years) were included in the study and randomized to either GH or placebo in a dose of 0.25 U/kg body weight/week. After 6 months all patients received GH. After a 1-year double-blind, placebo-controlled study the patients were followed for another 72 months in an open study. The patients were compared to 20 age- und sex-matched healthy controls. Bone turnover was determined by ICTP (type I collagen carboxyterminal cross-linked telopeptide) as parameter of bone resorption and PICP (carboxyterminal propeptide of type I procollagen) as marker of bone formation. BMD was measured at the lumbar spine by dual-photon absorptiometry (DPA) and at the forearm by single-photon absorptiometry (SPA). Apparent phalangeal ultrasound transmission velocity (APU) was assessed as parameter of bone quality independent of BMD. At the beginning of the study BMD at both measuring sites was lower in patients with GHD than in healthy controls. During the 1st year of GH replacement therapy BMD decreased, followed by a continuous increase in BMD (about 12%) up to 60 months which remained unchanged thereafter, building up a plateau. After 72 months no significant difference between the patients and the healthy controls could be detected. Concerning parameters of bone turnover, first ICTP as marker of bone resorption showed a significant increase, later on the marker of bone formation increased as well. APU decreased during the first 6 months of treatment, but had returned to its baseline value after 24 months and remained unchanged throughout the rest of the study. BMD is subnormal in adults with GHD. GH replacement therapy stimulates bone turnover in patients with GHD and in the long term such stimulation results in an increased BMD. Thereby, GH shows a triphasic action on BMD: an initial decrease in BMD during the 1st year, followed by a continuous increase in BMD with buildup of a stable plateau after 60 months. The newly formed bone seems to have normal bone elasticity.
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3D printing of high-strength bioscaffolds for the synergistic treatment of bone cancer
NASA Astrophysics Data System (ADS)
Ma, Hongshi; Li, Tao; Huan, Zhiguang; Zhang, Meng; Yang, Zezheng; Wang, Jinwu; Chang, Jiang; Wu, Chengtie
2018-04-01
The challenges in bone tumor therapy are how to repair the large bone defects induced by surgery and kill all possible residual tumor cells. Compared to cancellous bone defect regeneration, cortical bone defect regeneration has a higher demand for bone substitute materials. To the best of our knowledge, there are currently few bifunctional biomaterials with an ultra-high strength for both tumor therapy and cortical bone regeneration. Here, we designed Fe-CaSiO3 composite scaffolds (30CS) via 3D printing technique. First, the 30CS composite scaffolds possessed a high compressive strength that provided sufficient mechanical support in bone cortical defects; second, synergistic photothermal and ROS therapies achieved an enhanced tumor therapeutic effect in vitro and in vivo. Finally, the presence of CaSiO3 in the composite scaffolds improved the degradation performance, stimulated the proliferation and differentiation of rBMSCs, and further promoted bone formation in vivo. Such 30CS scaffolds with a high compressive strength can function as versatile and efficient biomaterials for the future regeneration of cortical bone defects and the treatment of bone cancer.
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Wu, Chengtie; Han, Pingping; Liu, Xiaoguo; Xu, Mengchi; Tian, Tian; Chang, Jiang; Xiao, Yin
2014-01-01
The nanostructured surface of biomaterials plays an important role in improving their in vitro cellular bioactivity as well as stimulating in vivo tissue regeneration. Inspired by the mussel's adhesive versatility, which is thought to be due to the plaque-substrate interface being rich in 3,4-dihydroxy-l-phenylalamine (DOPA) and lysine amino acids, in this study we developed a self-assembly method to prepare a uniform calcium phosphate (Ca-P)/polydopamine composite nanolayer on the surface of β-tricalcium phosphate (β-TCP) bioceramics by soaking β-TCP bioceramics in Tris-dopamine solution. It was found that the addition of dopamine, reaction temperature and reaction time are three key factors inducing the formation of a uniform Ca-P/polydopamine composite nanolayer. The formation mechanism of a Ca-P/polydopamine composite nanolayer involved two important steps: (i) the addition of dopamine to Tris-HCl solution decreases the pH value and accelerates Ca and P ionic dissolution from the crystal boundaries of β-TCP ceramics; (ii) dopamine is polymerized to form self-assembled polydopamine film and, at the same time, nanosized Ca-P particles are mineralized with the assistance of polydopamine, in which the formation of polydopamine occurs simultaneously with Ca-P mineralization (formation of nanosized microparticles composed of calcium phosphate-based materials), and finally a self-assembled Ca-P/polydopamine composite nanolayer forms on the surface of the β-TCP ceramics. Furthermore, the formed self-assembled Ca-P/polydopamine composite nanolayer significantly enhances the surface roughness and hydrophilicity of β-TCP ceramics, and stimulates the attachment, proliferation, alkaline phosphate (ALP) activity and bone-related gene expression (ALP, OCN, COL1 and Runx2) of human bone marrow stromal cells. Our results suggest that the preparation of self-assembled Ca-P/polydopamine composite nanolayers is a viable method to modify the surface of biomaterials by significantly improving their surface physicochemical properties and cellular bioactivity for bone regeneration application. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
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Mechanical control of tissue-engineered bone.
Hung, Ben P; Hutton, Daphne L; Grayson, Warren L
2013-01-31
Bone is a load-bearing tissue and physical forces play key roles in the development and maintenance of its structure. Mechanical cues can stimulate the expression of an osteogenic phenotype, enhance matrix and mineral deposition, and influence tissue organization to improve the functional outcome of engineered bone grafts. In recent years, a number of studies have investigated the effects of biophysical forces on the bone formation properties of osteoprogenitor cells. The application of physiologically relevant stimuli to tissue-engineered bone may be determined through observation and understanding of forces to which osteoblasts, osteoclasts, and osteocytes are exposed in native bone. Subsequently, these cues may be parameterized and their effects studied in well-defined in vitro systems. The osteo-inductive effects of three specific mechanical cues - shear stress, substrate rigidity, and nanotopography - on cells cultured in monolayer or in three-dimensional biomaterial scaffolds in vitro are reviewed. Additionally, we address the time-dependent effects of mechanical cues on vascular infiltration and de novo bone formation in acellular scaffolds implanted into load-bearing sites in vivo. Recent studies employing cutting-edge advances in biomaterial fabrication and bioreactor design have provided key insights into the role of mechanical cues on cellular fate and tissue properties of engineered bone grafts. By providing mechanistic understanding, future studies may go beyond empirical approaches to rational design of engineering systems to control tissue development.
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NASA Technical Reports Server (NTRS)
Yamaguchi, T.; Chattopadhyay, N.; Kifor, O.; Brown, E. M.; O'Malley, B. W. (Principal Investigator)
1998-01-01
The calcium-sensing receptor (CaR) is a G protein-coupled receptor that plays key roles in extracellular calcium ion (Ca2+(o)) homeostasis by mediating the actions of Ca2+(o) on parathyroid gland and kidney. Bone marrow stromal cells support the formation of osteoclasts from their progenitors as well as the growth of hematopoietic stem cells by secreting humoral factors and through cell to cell contact. Stromal cells also have the capacity to differentiate into bone-forming osteoblasts. Bone resorption by osteoclasts probably produces substantial local increases in Ca2+(o) that could provide a signal for stromal cells in the immediate vicinity, leading us to determine whether such stromal cells express the CaR. In this study, we used the murine bone marrow-derived, stromal cell line, ST2. Both immunocytochemistry and Western blot analysis, using an antiserum specific for the CaR, detected CaR protein in ST2 cells. We also identified CaR transcripts in ST2 cells by Northern analysis using a CaR-specific probe and by RT-PCR with CaR-specific primers, followed by nucleotide sequencing of the amplified products. Exposure of ST2 cells to high Ca2+(o) (4.8 mM) or to the polycationic CaR agonists, neomycin (300 microM) or gadolinium (100 microM), stimulated both chemotaxis and DNA synthesis in ST2 cells. Therefore, taken together, our data strongly suggest that the bone marrow-derived stromal cell line, ST2, possesses both CaR protein and messenger RNA that are very similar if not identical to those in parathyroid and kidney. Furthermore, as ST2 cells have the potential to differentiate into osteoblasts, the CaR in stromal cells could participate in bone turnover by stimulating the proliferation and migration of such cells to sites of bone resorption as a result of local, osteoclast-mediated release of Ca2+(o) and, thereafter, initiating bone formation after their differentiation into osteoblasts.
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Liu, Hao; Li, Wei; Ge, Xiyuan; Jia, Shengnan; Li, Binbin
2016-12-01
Puerarin is a phytoestrogen that shows osteogenic effects. Meanwhile, zinc stimulates bone formation and inhibits bone resorption. The study aims to investigate the effects of coadministration of puerarin (low dose) and zinc on bone formation in ovariectomized rats. Co-administration or use alone of puerarin (low dose) and/or zinc were gavaged in OVX rats. The estrogen-like effects were detected by the uterus weight, the histologic observation and the IGF-1 protein expression. The osteogenic effects were determined by bone histomorphometric and mechanical parameters, osteogenic and adipogenic blood markers, and so on. The results showed that oral administration of puerarin (low dose) plus zinc didn't significantly increase uterus weight. The glandular epithelial of endometrium had no proliferation and no protein expression of IGF-1. Moreover, co-administration attenuated bone loss and biomechanical decrease more than single use of puerarin or zinc (p<0.05). Next, combined administration of puerarin and zinc promoted the serological level of osteocalcin, bone marrow stromal cell (BMSC) proliferation, and the expression of alkaline phosphatase (ALP), and suppressed the serological level of adiponectin and adiposity in bone marrow (BM). In conclusion, co-administrated puerarin (low dose) and zinc can partially reverse OVX-induced bone loss and suppress the adiposity of BM in rats, which shed light on the potential use of puerarin and zinc in the treatment of osteoporosis. Copyright © 2016 Elsevier Inc. All rights reserved.
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Lin, Guanlin; Wang, Huan; Dai, Jun; Li, Xiao; Guan, Ming; Gao, Shutao; Ding, Qing; Wang, Huaixi; Fang, Huang
2017-08-26
Osteoporosis (OP) can increase the risk of bone fracture and other complications, which is a major clinical problem. Previous researches have revealed that conjugated linoleic acid (CLA) can promote the bone formation. But the mechanisms are not clear. Thus, we tested the hypothesis that CLA acts on bone formation might be via mTOR Complex1 (mTORC 1) pathway by in vitro and vivo assays. We studied the effect of CLA mix on MC3T3-E1 pre-osteoblasts differentiation into osteoblasts, and bone formation under osteoporotic conditions. At the same time, 3T3-L1 pre-adipocyte with the same CLA mix concentration gradient for 8 days with adipogenic differentiation medium. We found that Alkaline phosphatase (ALP), runt-related transcription factor 2 (RUNX2) and osteocalcin (OCN) expressions of pre-osteoblasts were up-regulated. Moreover in presence of CLA, peroxisome proliferators-activated receptor γ(PPARγ) and CCAAT/enhancer-binding protein (C/EBPα) were down-regulated. Osteoporosis mice bone parameters in the distal femoral meraphysis were significantly increased compared with placebo mice. Furthermore, the phosphor-S6 (P-S6) was suppressed and phosphor-AKT (P-AKT) was up-regulated. Consistently, CLA can stimulate differentiation of osteoblasts and inhibited pre-adipocytes differentiated into adipocytes via AKT/mTORC1 signal pathway. Overall CLA thus be a suitable candidate for the treatment of patients with postmenopausal osteoporosis and obesity. Copyright © 2017 Elsevier Inc. All rights reserved.
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Ren, Li; Yang, Pengfei; Wang, Zhe; Zhang, Jian; Ding, Chong; Shang, Peng
2015-10-01
Bones with complicated hierarchical configuration and microstructures constitute the load-bearing system. Mechanical loading plays an essential role in maintaining bone health and regulating bone mechanical adaptation (modeling and remodeling). The whole-bone or sub-region (macroscopic) mechanical signals, including locomotion-induced loading and external actuator-generated vibration, ultrasound, oscillatory skeletal muscle stimulation, etc., give rise to sophisticated and distinct biomechanical and biophysical environments at the pericellular (microscopic) and collagen/mineral molecular (nanoscopic) levels, which are the direct stimulations that positively influence bone adaptation. While under microgravity, the stimulations decrease or even disappear, which exerts a negative influence on bone adaptation. A full understanding of the biomechanical and biophysical environment at different levels is necessary for exploring bone biomechanical properties and mechanical adaptation. In this review, the mechanical transferring theories from the macroscopic to the microscopic and nanoscopic levels are elucidated. First, detailed information of the hierarchical structures and biochemical composition of bone, which are the foundations for mechanical signal propagation, are presented. Second, the deformation feature of load-bearing bone during locomotion is clarified as a combination of bending and torsion rather than simplex bending. The bone matrix strains at microscopic and nanoscopic levels directly induced by bone deformation are critically discussed, and the strain concentration mechanism due to the complicated microstructures is highlighted. Third, the biomechanical and biophysical environments at microscopic and nanoscopic levels positively generated during bone matrix deformation or by dynamic mechanical loadings induced by external actuators, as well as those negatively affected under microgravity, are systematically discussed, including the interstitial fluid flow (IFF) within the lacunar-canalicular system and at the endosteum, the piezoelectricity at the deformed bone surface, and the streaming potential accompanying the IFF. Their generation mechanisms and the regulation effect on bone adaptation are presented. The IFF-induced chemotransport effect, shear stress, and fluid drag on the pericellular matrix are meaningful and noteworthy. Furthermore, we firmly believe that bone adaptation is regulated by the combination of bone biomechanical and biophysical environment, not only the commonly considered matrix strain, fluid shear stress, and hydrostatic pressure, but also the piezoelectricity and streaming potential. Especially, it is necessary to incorporate bone matrix piezoelectricity and streaming potential to explain how osteoblasts (bone formation cells) and osteoclasts (bone resorption cells) can differentiate among different types of loads. Specifically, the regulation effects and the related mechanisms of the biomechanical and biophysical environments on bone need further exploration, and the incorporation of experimental research with theoretical simulations is essential. Copyright © 2015. Published by Elsevier Ltd.
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Bone morphogenetic protein 7 (BMP-7) influences tendon-bone integration in vitro.
Schwarting, Tim; Lechler, Philipp; Struewer, Johannes; Ambrock, Marius; Frangen, Thomas Manfred; Ruchholtz, Steffen; Ziring, Ewgeni; Frink, Michael
2015-01-01
Successful graft ingrowth following reconstruction of the anterior cruciate ligament is governed by complex biological processes at the tendon-bone interface. The aim of this study was to investigate in an in vitro study the effects of bone morphogenetic protein 7 (BMP-7) on tendon-bone integration. To study the biological effects of BMP-7 on the process of tendon-bone-integration, two independent in vitro models were used. The first model involved the mono- and coculture of bovine tendon specimens and primary bovine osteoblasts with and without BMP-7 exposure. The second model comprised the mono- and coculture of primary bovine osteoblasts and fibroblasts. Alkaline phosphatase (ALP), lactate dehydrogenase (LDH), lactate and osteocalcin (OCN) were analyzed by ELISA. Histological analysis and electron microscopy of the tendon specimens were performed. In both models, positive effects of BMP-7 on ALP enzyme activity were observed (p<0.001). Additionally, similar results were noted for LDH activity and lactate concentration. BMP-7 stimulation led to a significant increase in OCN expression. Whereas the effects of BMP-7 on tendon monoculture peaked during an early phase of the experiment (p<0.001), the cocultures showed a maximal increase during the later stages (p<0.001). The histological analysis showed a stimulating effect of BMP-7 on extracellular matrix formation. Organized ossification zones and calcium carbonate-like structures were only observed in the BMP-stimulated cell cultures. This study showed the positive effects of BMP-7 on the biological process of tendon-bone integration in vitro. Histological signs of improved mineralization were paralleled by increased rates of osteoblast-specific protein levels in primary bovine osteoblasts and fibroblasts. Our findings indicated a role for BMP-7 as an adjuvant therapeutic agent in the treatment of ligamentous injuries, and they emphasized the importance of the transdifferentiation process of tendinous fibroblasts at the tendon-bone interface.
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A theoretical framework for strain-related trabecular bone maintenance and adaptation.
Ruimerman, R; Hilbers, P; van Rietbergen, B; Huiskes, R
2005-04-01
It is assumed that density and morphology of trabecular bone is partially controlled by mechanical forces. How these effects are expressed in the local metabolic functions of osteoclast resorption and osteoblast formation is not known. In order to investigate possible mechano-biological pathways for these mechanisms we have proposed a mathematical theory (Nature 405 (2000) 704). This theory is based on hypothetical osteocyte stimulation of osteoblast bone formation, as an effect of elevated strain in the bone matrix, and a role for microcracks and disuse in promoting osteoclast resorption. Applied in a 2-D Finite Element Analysis model, the theory explained the formation of trabecular patterns. In this article we present a 3-D FEA model based on the same theory and investigated its potential morphological predictability of metabolic reactions to mechanical loads. The computations simulated the development of trabecular morphological details during growth, relative to measurements in growing pigs, reasonably realistic. They confirmed that the proposed mechanisms also inherently lead to optimal stress transfer. Alternative loading directions produced new trabecular orientations. Reduction of load reduced trabecular thickness, connectivity and mass in the simulation, as is seen in disuse osteoporosis. Simulating the effects of estrogen deficiency through increased osteoclast resorption frequencies produced osteoporotic morphologies as well, as seen in post-menopausal osteoporosis. We conclude that the theory provides a suitable computational framework to investigate hypothetical relationships between bone loading and metabolic expressions.
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Peripheral cannabinoid receptor, CB2, regulates bone mass
Ofek, Orr; Karsak, Meliha; Leclerc, Nathalie; Fogel, Meirav; Frenkel, Baruch; Wright, Karen; Tam, Joseph; Attar-Namdar, Malka; Kram, Vardit; Shohami, Esther; Mechoulam, Raphael; Zimmer, Andreas; Bab, Itai
2006-01-01
The endogenous cannabinoids bind to and activate two G protein-coupled receptors, the predominantly central cannabinoid receptor type 1 (CB1) and peripheral cannabinoid receptor type 2 (CB2). Whereas CB1 mediates the cannabinoid psychotropic, analgesic, and orectic effects, CB2 has been implicated recently in the regulation of liver fibrosis and atherosclerosis. Here we show that CB2-deficient mice have a markedly accelerated age-related trabecular bone loss and cortical expansion, although cortical thickness remains unaltered. These changes are reminiscent of human osteoporosis and may result from differential regulation of trabecular and cortical bone remodeling. The CB2–/– phenotype is also characterized by increased activity of trabecular osteoblasts (bone-forming cells), increased osteoclast (the bone-resorbing cell) number, and a markedly decreased number of diaphyseal osteoblast precursors. CB2 is expressed in osteoblasts, osteocytes, and osteoclasts. A CB2-specific agonist that does not have any psychotropic effects enhances endocortical osteoblast number and activity and restrains trabecular osteoclastogenesis, apparently by inhibiting proliferation of osteoclast precursors and receptor activator of NF-κB ligand expression in bone marrow-derived osteoblasts/stromal cells. The same agonist attenuates ovariectomy-induced bone loss and markedly stimulates cortical thickness through the respective suppression of osteoclast number and stimulation of endocortical bone formation. These results demonstrate that the endocannabinoid system is essential for the maintenance of normal bone mass by osteoblastic and osteoclastic CB2 signaling. Hence, CB2 offers a molecular target for the diagnosis and treatment of osteoporosis, the most prevalent degenerative disease in developed countries. PMID:16407142
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Huang, Chengcheng; Zhang, Meng; Ruan, Changshun; Peng, Songlin; Li, Li; Liu, Wenlong; Wang, Ting; Li, Bing; Huang, Wenhai; Rahaman, Mohamed N.; Lu, William W.; Pan, Haobo
2017-01-01
Although poly(methylmethacrylate) (PMMA) cements are widely used in orthopaedics, they have numerous drawbacks. This study aimed to improve their bioactivity and osseointegration by incorporating strontium-containing borate bioactive glass (SrBG) as the reinforcement phase and bioactive filler of PMMA cement. The prepared SrBG/PMMA composite cements showed significantly decreased polymerization temperature when compared with PMMA and retained properties of appropriate setting time and high mechanical strength. The bioactivity of SrBG/PMMA composite cements was confirmed in vitro, evidenced by ion release (Ca, P, B and Sr) from SrBG particles. The cellular responses of MC3T3-E1 cells in vitro demonstrated that SrBG incorporation could promote adhesion, migration, proliferation and collagen secretion of cells. Furthermore, our in vivo investigation revealed that SrBG/PMMA composite cements presented better osseointegration than PMMA bone cement. SrBG in the composite cement could stimulate new-bone formation around the interface between the composite cement and host bone at eight and 12 weeks post-implantation, whereas PMMA bone cement only stimulated development of an intervening connective tissue layer. Consequently, the SrBG/PMMA composite cement may be a better alternative to PMMA cement in clinical applications and has promising orthopaedic applications by minimal invasive surgery. PMID:28615491
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Cui, Xu; Huang, Chengcheng; Zhang, Meng; Ruan, Changshun; Peng, Songlin; Li, Li; Liu, Wenlong; Wang, Ting; Li, Bing; Huang, Wenhai; Rahaman, Mohamed N; Lu, William W; Pan, Haobo
2017-06-01
Although poly(methylmethacrylate) (PMMA) cements are widely used in orthopaedics, they have numerous drawbacks. This study aimed to improve their bioactivity and osseointegration by incorporating strontium-containing borate bioactive glass (SrBG) as the reinforcement phase and bioactive filler of PMMA cement. The prepared SrBG/PMMA composite cements showed significantly decreased polymerization temperature when compared with PMMA and retained properties of appropriate setting time and high mechanical strength. The bioactivity of SrBG/PMMA composite cements was confirmed in vitro , evidenced by ion release (Ca, P, B and Sr) from SrBG particles. The cellular responses of MC3T3-E1 cells in vitro demonstrated that SrBG incorporation could promote adhesion, migration, proliferation and collagen secretion of cells. Furthermore, our in vivo investigation revealed that SrBG/PMMA composite cements presented better osseointegration than PMMA bone cement. SrBG in the composite cement could stimulate new-bone formation around the interface between the composite cement and host bone at eight and 12 weeks post-implantation, whereas PMMA bone cement only stimulated development of an intervening connective tissue layer. Consequently, the SrBG/PMMA composite cement may be a better alternative to PMMA cement in clinical applications and has promising orthopaedic applications by minimal invasive surgery. © 2017 The Author(s).
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Porous CaP/silk composite scaffolds to repair femur defects in an osteoporotic model
Cheng, Ning; Dai, Jing; Cheng, Xiangrong; Li, Shu’e; Miron, Richard J.; Wu, Tao; Chen, Wenli; Zhang, Yufeng
2018-01-01
The most common complication for patients with postmenopausal osteoporosis is bone-related defects and fractures. While routine medication has a high probability of undesirable side effects, new approaches have aimed to develop regeneration procedures that stimulate new bone formation while reversing bone loss. Recently, we have synthesized a new hybrid CaP/silk scaffold with a CaP-phase distribution and pore architecture better suited to facilitate cell differentiation and bone formation. The aim of the present study was to compare the involved remodeling process and therapeutic effect of porous CaP/silk composite scaffolds upon local implantation into osteoporotic defects. Wistar rats were used to induce postmenopausal osteoporotic model by bilateral ovariectomy. The pure silk and hybrid CaP/silk scaffolds were implanted into critical sized defects created in distal femoral epiphysis. After 14 and 28 days, the in vivo osteogenetic efficiency was evaluated by μCT analysis, hematoxylin and eosin staining, Safranin O staining, tartrate-resistant acid phosphatase staining, and immunohistochemical assessment. Animals with or without critical-sized defects were used as drill or blank controls, respectively. The osteoporotic defect model was well established with significantly decreased μCT parameters of BV/TV, Tb.N and increased Tb.Sp, porosity, combined with changes in histological observations. During the healing process, the critical-sized drill control defects failed to regenerate appreciable bone tissue, while more significantly increased bone formation and mineralization with dynamic scaffold degradation and decreased osteoclastic bone resorption could be detected within defects with hybrid CaP/silk scaffolds compared to pure silk scaffolds. PMID:23674058
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Porous CaP/silk composite scaffolds to repair femur defects in an osteoporotic model.
Cheng, Ning; Dai, Jing; Cheng, Xiangrong; Li, Shu'e; Miron, Richard J; Wu, Tao; Chen, Wenli; Zhang, Yufeng; Shi, Bin
2013-08-01
The most common complication for patients with postmenopausal osteoporosis is bone-related defects and fractures. While routine medication has a high probability of undesirable side effects, new approaches have aimed to develop regeneration procedures that stimulate new bone formation while reversing bone loss. Recently, we have synthesized a new hybrid CaP/silk scaffold with a CaP-phase distribution and pore architecture better suited to facilitate cell differentiation and bone formation. The aim of the present study was to compare the involved remodeling process and therapeutic effect of porous CaP/silk composite scaffolds upon local implantation into osteoporotic defects. Wistar rats were used to induce postmenopausal osteoporotic model by bilateral ovariectomy. The pure silk and hybrid CaP/silk scaffolds were implanted into critical sized defects created in distal femoral epiphysis. After 14 and 28 days, the in vivo osteogenetic efficiency was evaluated by μCT analysis, hematoxylin and eosin staining, Safranin O staining, tartrate-resistant acid phosphatase staining, and immunohistochemical assessment. Animals with or without critical-sized defects were used as drill or blank controls, respectively. The osteoporotic defect model was well established with significantly decreased μCT parameters of BV/TV, Tb.N and increased Tb.Sp, porosity, combined with changes in histological observations. During the healing process, the critical-sized drill control defects failed to regenerate appreciable bone tissue, while more significantly increased bone formation and mineralization with dynamic scaffold degradation and decreased osteoclastic bone resorption could be detected within defects with hybrid CaP/silk scaffolds compared to pure silk scaffolds.
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Mechanisms of bone remodeling: implications for clinical practice.
Kenny, Anne M; Raisz, Lawrence G
2002-01-01
The adult skeleton undergoes continuous remodeling. The remodeling cycle involves the interaction of cells of osteoblastic and osteoclastic lineage and is regulated by both systemic hormones and local factors. In addition to the systemic calcium-regulating hormones, parathyroid hormone, 1,25-dihydroxy vitamin D and calcitonin, sex hormones play an important role. Estrogen has been identified as the major inhibitor of bone resorption in both men and women. Androgen is important not only as a source of estrogen, through the action of aromatase, but also for its direct effect in stimulating bone formation. The effects of sex hormones may be mediated by their ability to alter the secretion of local cytokines, prostaglandins and growth factors. Sex hormone action is also modulated by the level of sex hormone-binding globulin in the circulation. A more precise analysis of these effects has been made possible by the development of new methods of measuring not only bone mineral density, but also relative rates of bone formation and resorption using biochemical markers. These new approaches have allowed us to define more precisely the specific roles of androgens, estrogens and other regulatory hormones in human skeletal physiology and pathophysiology.
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van Laack, R L; Smulders, F J
1990-01-01
From eight electrically stimulated and eight non-stimulated cows the righthand-side longissimus and psoas major muscles were hot boned within 1 1 2 h post mortem, vacuum packaged and chilled and storred at 1±1°C. Immediately after slaughter, the lefthand carcass-sides were blast-chilled for 1 1 2 h and subsequently chilled at 1±1°C until the following day. After cold boning, the longissimus and psoas major muscle were packaged, chilled and stored as the hot boned muscles. After 12 days of storage, steaks, cut from the primals, were displayed at 1±1°C under continuous illumination (300-400 lx). Colour measurements after 0, 2 and 4 days of display revealed a significant (p<0·10) effect of time of boning on non-stimulated psoas major muscle (lower values for a (∗), b (∗) values, chroma and %R630-%R580). Significant effects of electrical stimulation were not observed. Changes in hue tended to be more pronounced when the meat had been stimulated. Changes in chroma were largest (p<0·10) is non-stimulated, hot boned psoas muscle. Analysis of variances showed that in the longissimus muscle significant effects (p<0·10) of time boning and electrical stimulation were present. The effect of time of boning was often influenced by the use of electrical stimulation. Changes in hue and chroma indicated that hot boned samples had a higher colour stability than cold boned controls, especially when the carcasses had not been stimulated electrically. The observed differences in colour stability were rather small in all treatment groups and are not expected to present any practical merchandising problem. Copyright © 1990. Published by Elsevier Ltd.
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Digital electronic bone growth stimulator
Kronberg, James W.
1995-01-01
A device for stimulating bone tissue by applying a low level alternating current signal directly to the patient's skin. A crystal oscillator, a binary divider chain and digital logic gates are used to generate the desired waveforms that reproduce the natural electrical characteristics found in bone tissue needed for stimulating bone growth and treating osteoporosis. The device, powered by a battery, contains a switch allowing selection of the correct waveform for bone growth stimulation or osteoporosis treatment so that, when attached to the skin of the patient using standard skin contact electrodes, the correct signal is communicated to the underlying bone structures.
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Saxena, Ritu; Pan, George; Dohm, Erik D.; McDonald, Jay M.
2010-01-01
Mechanical forces are essential to maintain skeletal integrity, and microgravity exposure leads to bone loss. The underlying molecular mechanisms leading to the changes in osteoblasts and osteoclast differentiation and function remain be to fully elucidated. Due to the infrequency of spaceflights and payload constraints, establishing in vitro and in vivo systems that mimic microgravity conditions becomes necessary. We have established a simulated microgravity (modeled microgravity, MMG) system to study the changes induced in osteoclast precursors. We observed that MMG, on its own was unable to induce osteoclastogenesis of osteoclast precursors, however, 24h of MMG activates osteoclastogenesis-related signaling molecules ERK, p38, PLCγ2, and NFATc1. RANKL (and/or M-CSF) stimulation for 3-4 days in gravity of cells that had been exposed to MMG for 24h, enhanced the formation of very large TRAP positive multinucleated (>30 nuclei) osteoclasts accompanied by an upregulation of osteoclast marker genes- TRAP and cathepsin K. To validate the in vitro system, we established the hindlimb unloading system using BALB/c mice and observed a decrease in BMD of femurs and a loss of 3D microstructure of both cortical and trabecular bone as determined by microCT. There was a marked stimulation of osteoclastogenesis as determined by the total number of TRAP positive multinucleated osteoclasts formed and also an increase in RANKL stimulated osteoclastogenesis from precursors removed from the tibias of mice after 28 days of hindlimb unloading. Contrary to earlier reported findings, we did not observe any histomorphometrical changes in the bone formation parameters. Thus, the above observations indicate that microgravity sensitizes osteoclast precursors for increased differentiation. The in vitro model system described here is potentially a valid system for testing drugs for preventing microgravity induced bone loss by targeting the molecular events occurring in microgravity-induced enhanced osteoclastogenesis. PMID:20589403
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Ahn, Ki Hoon; Lee, Seung Hyeun; Park, Hyun Tae; Kim, Tak; Hur, Jun Young; Kim, Young Tae; Kim, Sun Haeng
2010-04-01
The relationship between adiponectin and sex hormones with bone mineral density (BMD) and bone formation markers was investigated in postmenopausal women with subclinical hyperthyroidism (SCH). Seventy-five postmenopausal women were selected among the patients who participated in a health screening program in 2007. Thirty-seven control women with normal thyroid function were matched to 38 women with SCH by age, body mass index (BMI), and years since menopause (YSM). The associations between adiponectin and sex hormones with lumbar spine BMD and bone turnover markers were investigated. Adiponectin, testosterone (T; total and free forms), and thyroid-stimulating hormone were significantly different between the women with SCH and euthyroid. After adjusting for age, BMI, and YSM, free T (r = 0.351; P = 0.029) and estradiol (E2; r = -0.368; P = 0.024) had significant associations with bone alkaline phosphatase (B-ALP). Total T (r = 0.388; P = 0.021) and E2 (r = -0.376; P = 0.026) had significant associations with osteocalcin. However, there were no significant associations between adiponectin and sex hormones with the BMD levels in the SCH subjects. There were correlations between sex hormones with B-ALP and osteocalcin, but no associations between adiponectin and sex hormones with the lumbar spine BMD in postmenopausal SCH patients.
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Yamaguchi, Masayoshi; Weitzmann, M Neale
2011-01-01
Several bone protective factors are reported to exhibit stimulatory activities on bone formation coupled with inhibitory effects on bone resorption; one such factor is vitamin K2. Vitamin K species [K1 (phylloquinone) and K2 (menaquinone)] have long been associated with bone protective activities and are receiving intense interest as nutritional supplements for the prevention or amelioration of bone disease in humans. However, the mechanisms of vitamin K action on the skeleton are poorly defined. Activation of the nuclear factor κB (NF-κB) signal transduction pathway is essential for osteoclast formation and resorption. By contrast, NF-κB signaling potently antagonizes osteoblast differentiation and function, prompting us to speculate that NF-κB antagonists may represent a novel class of dual anti-catabolic and pro-anabolic agents. We now show that vitamin K2 action on osteoblast and osteoclast formation and activity is accomplished by down-regulating basal and cytokine-induced NF-κB activation, by increasing IκB mRNA, in a γ-carboxylation-independent manner. Furthermore, vitamin K2 prevented repression by tumor necrosis factor α (TNFα) of SMAD signaling induced by either transforming growth factor ß (TGFß) or bone morphogenetic protein-2 (BMP-2). Vitamin K2 further antagonized receptor activator of NF-κB (RANK) ligand (RANKL)-induced NF-κB activation in osteoclast precursors. Our data provide a novel mechanism to explain the dual pro-anabolic and anti-catabolic activities of vitamin K2, and may further support the concept that pharmacological modulation of NF-κB signal transduction may constitute an effective mechanism for ameliorating pathological bone loss and for promoting bone health.
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Lee, Jinkyu; Perikamana, Sajeesh Kumar Madhurakkat; Ahmad, Taufiq; Lee, Min Suk; Yang, Hee Seok; Kim, Do-Gyoon; Kim, Kyobum; Kwon, Bosun; Shin, Heungsoo
2017-04-01
Although bone morphogenetic protein-2 (BMP-2) has been frequently used to stimulate bone formation, it has several side effects to be addressed, including the difficulty in optimization of clinically relevant doses and unwanted induction of cancerous signaling processes. In this study, an osteogenic peptide (OP) derived from BMP-2 was investigated as a substitute for BMP-2. In vitro studies showed that OP was able to enhance the osteogenic differentiation and mineralization of human mesenchymal stem cells (hMSCs). The peptides were then conjugated onto biocompatible poly-ι-lactide electrospun nanofibers through polydopamine chemistry. Surface chemical analysis proved that more than 80% of the peptides were stably retained on the nanofiber surface after 8 h of polydopamine coating during at least 28 days, and the amount of peptides that was retained increased depending on the polydopamine coating time. For instance, about 65% of the peptides were retained on nanofibers after 4 h of polydopamine coating. Also, a relatively small dose of peptides could effectively induce bone formation in in vivo critical-sized defects on the calvarial bones of mice. More than 50.4% ± 16.9% of newly formed bone was filled within the defect after treatment with only 10.5 ± 0.6 μg of peptides. Moreover, these groups had similar elastic moduli and contact hardnesses with host bone. Taken together, our results suggest that polydopamine-mediated OP immobilized on nanofibers can modulate the retention of relatively short lengths of peptides, which might make this an effective therapeutic remedy to guide bone regeneration using a relatively small amount of peptides.
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Schröder, Heinz C; Müller, Werner E G
2014-01-01
Summary Calcium carbonate is the material that builds up the spicules of the calcareous sponges. Recent results revealed that the calcium carbonate/biocalcite-based spicular skeleton of these animals is formed through an enzymatic mechanism, such as the skeleton of the siliceous sponges, evolutionarily the oldest animals that consist of biosilica. The enzyme that mediates the calcium carbonate deposition has been identified as a carbonic anhydrase (CA) and has been cloned from the calcareous sponge species Sycon raphanus. Calcium carbonate deposits are also found in vertebrate bones besides the main constituent, calcium phosphate/hydroxyapatite (HA). Evidence has been presented that during the initial phase of HA synthesis poorly crystalline carbonated apatite is deposited. Recent data summarized here indicate that during early bone formation calcium carbonate deposits enzymatically formed by CA, act as potential bioseeds for the precipitation of calcium phosphate mineral onto bone-forming osteoblasts. Two different calcium carbonate phases have been found during CA-driven enzymatic calcium carbonate deposition in in vitro assays: calcite crystals and round-shaped vaterite deposits. The CA provides a new target of potential anabolic agents for treatment of bone diseases; a first CA activator stimulating the CA-driven calcium carbonate deposition has been identified. In addition, the CA-driven calcium carbonate crystal formation can be frozen at the vaterite state in the presence of silintaphin-2, an aspartic acid/glutamic acid-rich sponge-specific protein. The discovery that calcium carbonate crystals act as bioseeds in human bone formation may allow the development of novel biomimetic scaffolds for bone tissue engineering. Na-alginate hydrogels, enriched with biosilica, have recently been demonstrated as a suitable matrix to embed bone forming cells for rapid prototyping bioprinting/3D cell printing applications. PMID:24991497
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Wang, Xiaohong; Schröder, Heinz C; Müller, Werner E G
2014-01-01
Calcium carbonate is the material that builds up the spicules of the calcareous sponges. Recent results revealed that the calcium carbonate/biocalcite-based spicular skeleton of these animals is formed through an enzymatic mechanism, such as the skeleton of the siliceous sponges, evolutionarily the oldest animals that consist of biosilica. The enzyme that mediates the calcium carbonate deposition has been identified as a carbonic anhydrase (CA) and has been cloned from the calcareous sponge species Sycon raphanus. Calcium carbonate deposits are also found in vertebrate bones besides the main constituent, calcium phosphate/hydroxyapatite (HA). Evidence has been presented that during the initial phase of HA synthesis poorly crystalline carbonated apatite is deposited. Recent data summarized here indicate that during early bone formation calcium carbonate deposits enzymatically formed by CA, act as potential bioseeds for the precipitation of calcium phosphate mineral onto bone-forming osteoblasts. Two different calcium carbonate phases have been found during CA-driven enzymatic calcium carbonate deposition in in vitro assays: calcite crystals and round-shaped vaterite deposits. The CA provides a new target of potential anabolic agents for treatment of bone diseases; a first CA activator stimulating the CA-driven calcium carbonate deposition has been identified. In addition, the CA-driven calcium carbonate crystal formation can be frozen at the vaterite state in the presence of silintaphin-2, an aspartic acid/glutamic acid-rich sponge-specific protein. The discovery that calcium carbonate crystals act as bioseeds in human bone formation may allow the development of novel biomimetic scaffolds for bone tissue engineering. Na-alginate hydrogels, enriched with biosilica, have recently been demonstrated as a suitable matrix to embed bone forming cells for rapid prototyping bioprinting/3D cell printing applications.
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Leptin stimulates bone formation in ob/ob mice at doses having minimal impact on energy metabolism.
Philbrick, Kenneth A; Wong, Carmen P; Branscum, Adam J; Turner, Russell T; Iwaniec, Urszula T
2017-03-01
Leptin, the protein product of the ob gene, is essential for normal bone growth, maturation and turnover. Peripheral actions of leptin occur at lower serum levels of the hormone than central actions because entry of leptin into the central nervous system (CNS) is limited due to its saturable transport across the blood-brain barrier (BBB). We performed a study in mice to model the impact of leptin production associated with different levels of adiposity on bone formation and compared the response with well-established centrally mediated actions of the hormone on energy metabolism. Leptin was infused (0, 4, 12, 40, 140 or 400 ng/h) for 12 days into 6-week-old female ob/ob mice (n = 8/group) using sc-implanted osmotic pumps. Treatment resulted in a dose-associated increase in serum leptin. Bone formation parameters were increased at EC 50 infusion rates of 7-17 ng/h, whereas higher levels (EC 50 , 40-80 ng/h) were required to similarly influence indices of energy metabolism. We then analyzed gene expression in tibia and hypothalamus at dose rates of 0, 12 and 140 ng/h; the latter dose resulted in serum leptin levels similar to WT mice. Infusion with 12 ng/h leptin increased the expression of genes associated with Jak/Stat signaling and bone formation in tibia with minimal effect on Jak/Stat signaling and neurotransmitters in hypothalamus. The results suggest that leptin acts peripherally to couple bone acquisition to energy availability and that limited transport across the BBB insures that the growth-promoting actions of peripheral leptin are not curtailed by the hormone's CNS-mediated anorexigenic actions. © 2017 Society for Endocrinology.
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Reis-Filho, Cláudio R; Silva, Elisângela R; Martins, Adalberto B; Pessoa, Fernanda F; Gomes, Paula V N; de Araújo, Mariana S C; Miziara, Melissa N; Alves, José B
2012-05-01
In this study we investigated the possible use of human demineralised dentine matrix (DHDM), obtained from the extracted teeth, as bone graft material and evaluated the expression of vascular endothelial growth factor (VEGF) induced by this material in the healing process of tooth sockets of rats. To evaluate bone regeneration and expression of VEGF induced by DHDM, thirty-two male Wistar rats weighing approximately 200 g were used. After maxillary second molar extraction, the left sockets were filled with DHDM and the right sockets were naturally filled by blood clot (control). The animals were sacrificed at 3, 7, 14 and 21 days after surgery and upper maxillaries were processed for histological, morphometric and immunohistochemical analyses. DHDM was used to evaluate the mechanical effect of bone graft material into sockets. Expression of VEGF was determined by immunohistochemistry in all groups. Our results demonstrated a significant increase in the newly formed bone tissue in sockets of 7, 14 and 21 days and a significant increase in VEGF expression at days 7 and 14 on treated sockets. Our results showed that DHDM increases the expression of VEGF and accelerates the healing process in rats tooth sockets, by stimulating bone deposition and also vessels formation. These results suggest that DHDM has osteoinductive/osteoconductive potential and may represent an efficient grafting material on guided bone regeneration. Copyright © 2011 Elsevier Ltd. All rights reserved.
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NASA Technical Reports Server (NTRS)
Bikle, D. D.; Morey-Holton, E. R.; Doty, S. B.; Currier, P. A.; Tanner, S. J.; Halloran, B. P.
1994-01-01
Loss of bone mass during periods of skeletal unloading remains an important clinical problem. To determine the extent to which resorption contributes to the relative loss of bone during skeletal unloading of the growing rat and to explore potential means of preventing such bone loss, 0.1 mg P/kg alendronate was administered to rats before unloading of the hindquarters. Skeletal unloading markedly reduced the normal increase in tibial mass and calcium content during the 9 day period of observation, primarily by decreasing bone formation, although bone resorption was also modestly stimulated. Alendronate not only prevented the relative loss of skeletal mass during unloading but led to a dramatic increase in calcified tissue in the proximal tibia compared with the vehicle-treated unloaded or normally loaded controls. Bone formation, however, assessed both by tetracycline labeling and by [3H]proline and 45Ca incorporation, was suppressed by alendronate treatment and further decreased by skeletal unloading. Total osteoclast number increased in alendronate-treated animals, but values were similar to those in controls when corrected for the increased bone area. However, the osteoclasts had poorly developed brush borders and appeared not to engage the bone surface when examined at the ultrastructural level. We conclude that alendronate prevents the relative loss of mineralized tissue in growing rats subjected to skeletal unloading, but it does so primarily by inhibiting the resorption of the primary and secondary spongiosa, leading to altered bone modeling in the metaphysis.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Nakamura, Ryosuke; Department of Maxillofacial Surgery, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo; Kayamori, Kou
Transforming growth factor beta (TGF-β) plays a significant role in the regulation of the tumor microenvironment. To explore the role of TGF-β in oral cancer-induced bone destruction, we investigated the immunohistochemical localization of TGF-β and phosphorylated Smad2 (p-Smad2) in 12 surgical specimens of oral squamous cell carcinoma (OSCC). These studies revealed TGF-β and p-Smad2 expression in cancer cells in all tested cases. Several fibroblasts located between cancer nests and resorbing bone expressed TGF-β in 10 out of 12 cases and p-Smad2 in 11 out of 12 cases. Some osteoclasts also exhibited p ∼ Smad2 expression. The OSCC cell line, HSC3, and themore » bone marrow-derived fibroblastic cell line, ST2, synthesized substantial levels of TGF-β. Culture media derived from HSC3 cells could stimulate Tgf-β1 mRNA expression in ST2 cells. Recombinant TGF-β1 could stimulate osteoclast formation induced by receptor activator of nuclear factor kappa-B ligand (RANKL) in RAW264 cells. TGF-β1 could upregulate the expression of p-Smad2 in RAW264 cells, and this action was suppressed by the addition of a neutralizing antibody against TGF-β or by SB431542. Transplantation of HSC3 cells onto the calvarial region of athymic mice caused bone destruction, associated with the expression of TGF-β and p-Smad2 in both cancer cells and stromal cells. The bone destruction was substantially inhibited by the administration of SB431542. The present study demonstrated that TGF-β synthesized by both cancer cells and stromal cells participates in the OSCC-induced bone destruction. - Highlights: • Cancer cell, fibroblastic cells, and osteoclasts at bone resorbing area by oral cancer exhibited TGF-β and p-Smad2. • TGF-β1 stimulated osteoclastogenesis induced by RAKL in RAW264 cell. • Xenograft model of oral cancer-induced bone resorption was substantially inhibited by SB431542. • TGF-β synthesized by both cancer cells and stromal cells participates in the OSCC-induced bone destruction.« less
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Kojima, Hiroko; Uemura, Toshimasa
2005-01-28
Core binding factor alpha-1 (Cbfa1), known as an essential transcription factor for osteogenic lineage, has two major N-terminal isoforms: Pebp2alphaA and Til-1. To study the roles of these isoforms in bone regeneration, we applied an adenoviral vector carrying their genes to transduce primary osteoprogenitor cells in vitro and in vivo. Overexpression of the two isoforms induced rapid and marked osteoblast differentiation, with Til-1 being more effective in vitro, by examination of the alkaline phosphatase activity, calcium content, and Alizarin red staining. Til-1 overexpressing cells/porous ceramic composites were transplanted into subcutaneous and bone defect sites in Fischer rats (cultured bone transplantation model) and markedly affected in vivo bone formation and osteoblast markers. The results demonstrated that the reconstitution of bone tissues, such as cortical bone and trabecular bone was accelerated by implantation of Til-1 overexpressing cells/porous ceramic composites. Moreover, the new bone formation by Til-1 overexpression appeared to reflect replacement of new bone within the implant boundaries. To ascertain whether implanted Cbfa1 overexpressing cells could differentiate into osteogenic cells to create bone or whether it stimulated the surrounding recipient tissue to regenerate bone, implanted male donor cells were visualized by fluorescent in situ hybridization analysis. The proportion of implanted cells in the presumptive bone forming region was over 80% and did not change throughout from 3 days to 8 weeks after implantation. These findings suggested that the newly formed bone in the porous area of the scaffold is mostly produced by the implanted donor cells or their derived cells, effectively by Til-1 overexpression.
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Boos, Anja M; Loew, Johanna S; Deschler, Gloria; Arkudas, Andreas; Bleiziffer, Oliver; Gulle, Heinz; Dragu, Adrian; Kneser, Ulrich; Horch, Raymund E; Beier, Justus P
2011-01-01
Abstract Bone tissue engineering approaches increasingly focus on the use of mesenchymal stem cells (MSC). In most animal transplantation models MSC are isolated and expanded before auto cell transplantation which might be critical for clinical application in the future. Hence this study compares the potential of directly auto-transplanted versus in vitro expanded MSC with or without bone morphogenetic protein-2 (BMP-2) to induce bone formation in a large volume ceramic bone substitute in the sheep model. MSC were isolated from bone marrow aspirates and directly auto-transplanted or expanded in vitro and characterized using fluorescence activated cell sorting (FACS) and RT-PCR analysis before subcutaneous implantation in combination with BMP-2 and β-tricalcium phosphate/hydroxyapatite (β-TCP/HA) granules. Constructs were explanted after 1 to 12 weeks followed by histological and RT-PCR evaluation. Sheep MSC were CD29+, CD44+ and CD166+ after selection by Ficoll gradient centrifugation, while directly auto-transplanted MSC-populations expressed CD29 and CD166 at lower levels. Both, directly auto-transplanted and expanded MSC, were constantly proliferating and had a decreasing apoptosis over time in vivo. Directly auto-transplanted MSC led to de novo bone formation in a heterotopic sheep model using a β-TCP/HA matrix comparable to the application of 60 μg/ml BMP-2 only or implantation of expanded MSC. Bone matrix proteins were up-regulated in constructs following direct auto-transplantation and in expanded MSC as well as in BMP-2 constructs. Up-regulation was detected using immunohistology methods and RT-PCR. Dense vascularization was demonstrated by CD31 immunohistology staining in all three groups. Ectopic bone could be generated using directly auto-transplanted or expanded MSC with β-TCP/HA granules alone. Hence BMP-2 stimulation might become dispensable in the future, thus providing an attractive, clinically feasible approach to bone tissue engineering. PMID:20636333
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Cmoch, Anna; Podszywalow-Bartnicka, Paulina; Palczewska, Malgorzata; Piwocka, Katarzyna; Groves, Patrick; Pikula, Slawomir
2014-01-01
Background Osteosarcoma (OS) is a highly aggressive bone cancer affecting children and young adults. Growing evidence connects the invasive potential of OS cells with their ability to form invadopodia (structures specialized in extracellular matrix proteolysis). Results In this study, we tested the hypothesis that commonly used in vitro stimulators of mineralization limit the invadopodia formation in OS cells. Here we examined the invasive potential of human osteoblast-like cells (Saos-2) and osteolytic-like (143B) OS cells treated with the stimulators of mineralization (ascorbic acid and B-glycerophosphate) and observed a significant difference in response of the tested cells to the treatment. In contrast to 143B cells, osteoblast-like cells developed a mineralization phenotype that was accompanied by a decreased proliferation rate, prolongation of the cell cycle progression and apoptosis. On the other hand, stimulators of mineralization limited osteolytic-like OS cell invasiveness into collagen matrix. We are the first to evidence the ability of 143B cells to degrade extracellular matrix to be driven by invadopodia. Herein, we show that this ability of osteolytic-like cells in vitro is limited by stimulators of mineralization. Conclusions Our study demonstrates that mineralization competency determines the invasive potential of cancer cells. A better understanding of the molecular mechanisms by which stimulators of mineralization regulate and execute invadopodia formation would reveal novel clinical targets for treating osteosarcoma. PMID:25314307
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Triiodothyronine increases calcium loss in a bed rest antigravity model for space flight.
Smith, Steven R; Lovejoy, Jennifer C; Bray, George A; Rood, Jennifer; Most, Marlene M; Ryan, Donna H
2008-12-01
Bed rest has been used as a model to simulate the effects of space flight on bone metabolism. Thyroid hormones accelerate bone metabolism. Thus, supraphysiologic doses of this hormone might be used as a model to accelerate bone metabolism during bed rest and potentially simulate space flight. The objective of the study was to quantitate the changes in bone turnover after low doses of triiodothyronine (T(3)) added to short-term bed rest. Nine men and 5 women were restricted to bed rest for 28 days with their heads positioned 6 degrees below their feet. Subjects were randomly assigned to receive either placebo or oral T(3) at doses of 50 to 75 microg/d in a single-blind fashion. Calcium balance was measured over 5-day periods; and T(3), thyroxine, thyroid-stimulating hormone, immunoreactive parathyroid hormone, osteocalcin, bone alkaline phosphatase, and urinary deoxypyridinoline were measured weekly. Triiodothyronine increased 2-fold in the men and 5-fold in the women during treatment, suppressing both thyroxine and thyroid-stimulating hormone. Calcium balance was negative by 300 to 400 mg/d in the T(3)-treated volunteers, primarily because of the increased fecal loss that was not present in the placebo group. Urinary deoxypyridinoline to creatinine ratio, a marker of bone resorption, increased 60% in the placebo group during bed rest, but more than doubled in the T(3)-treated subjects (P < .01), suggesting that bone resorption was enhanced by treatment with T(3). Changes in serum osteocalcin and bone-specific alkaline phosphatase, markers of bone formation, were similar in T(3)- and placebo-treated subjects. Triiodothyronine increases bone resorption and fecal calcium loss in subjects at bed rest.
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Kato, Akihito; Miyaji, Hirofumi; Ishizuka, Ryosuke; Tokunaga, Keisuke; Inoue, Kana; Kosen, Yuta; Yokoyama, Hiroyuki; Sugaya, Tsutomu; Tanaka, Saori; Sakagami, Ryuji; Kawanami, Masamitsu
2015-01-01
Objective : Biomodification of the root surface plays a major role in periodontal wound healing. Root surface modification with bone morphogenetic protein (BMP) stimulates bone and cementum-like tissue formation; however, severe ankylosis is simultaneously observed. Bio-safe collagen hydrogel scaffolds may therefore be useful for supplying periodontal ligament cells and preventing ankylosis. We examined the effects of BMP modification in conjunction with collagen hydrogel scaffold implantation on periodontal wound healing in dogs. Material and Methods: The collagen hydrogel scaffold was composed of type I collagen sponge and collagen hydrogel. One-wall infrabony defects (5 mm in depth, 3 mm in width) were surgically created in six beagle dogs. In the BMP/Col group, BMP-2 was applied to the root surface (loading dose; 1 µg/µl), and the defects were filled with collagen hydrogel scaffold. In the BMP or Col group, BMP-2 coating or scaffold implantation was performed. Histometric parameters were evaluated at 4 weeks after surgery. Results: Single use of BMP stimulated formation of alveolar bone and ankylosis. In contrast, the BMP/Col group frequently enhanced reconstruction of periodontal attachment including cementum-like tissue, periodontal ligament and alveolar bone. The amount of new periodontal ligament in the BMP/Col group was significantly greater when compared to all other groups. In addition, ankylosis was rarely observed in the BMP/Col group. Conclusion: The combination method using root surface modification with BMP and collagen hydrogel scaffold implantation facilitated the reestablishment of periodontal attachment. BMP-related ankylosis was suppressed by implantation of collagen hydrogel. PMID:25674172
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Min, Shao-xiong; Jin, An-min; Tong, Bin-hui; Zhu, Li-xin; Tian, Jing
2003-04-01
To investigate the osteoinductive ability of the composites consisting of basic fibroblast growth factor (bFGF) and porous poly-DL-lactide (PDLLA) for the development of a new absorbable osteosynthesis material. Highly porous foams of PDLLA with the pore size ranging from 150 to 300 microm were prepared by a solvent-casting, particulate-leaching technique with NaCl as the leachable component. Animal models of radial diaphyseal defects of 1.0 cm with complete removal of the periosteum were induced in 45 rabbits, which were randomly divided into 3 groups to receive the defect repair with PDLLA and PDLLA/bFGF respectively, leaving one group untreated to serve as the control group. The implant specimens were harvested at 2, 4, 8, and 12 weeks respectively after the surgery and X-ray, histological and scanning electron microscopic (SEM) examinations were performed to evaluate the effectiveness of defect repair. At 8 and 12 weeks after implantation, biomechanical test (for three-point bending strength) was employed to study the quality of bone formation. PDLLA/bFGF composite stimulated more bone formation and had higher bending strength than PDLLA (P<0.05), and the bone formation induced by both materials was significantly more than that observed in the control group in every postoperative stage (P<0.05). PDLLA possesses good biocompatibility and absorbability, and when prepared into a porous material, it exhibits good osteoconductibility. As a good bFGF carrier, the foam of PDLLA with three- dimensional structure shows good osteoinductive ability with regard to the rapidity, quantity and quality of the bone formation.
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Tan, Cong-Cong; Li, Gui-Xi; Tan, Li-Duan; Du, Xin; Li, Xiao-Qing; He, Rui; Wang, Qing-Shan; Feng, Yu-Mei
2016-11-29
Bone is one of the most common organs of breast cancer metastasis. Cancer cells that mimic osteoblasts by expressing bone matrix proteins and factors have a higher likelihood of metastasizing to bone. However, the molecular mechanisms of osteomimicry formation of cancer cells remain undefined. Herein, we identified a set of bone-related genes (BRGs) that are ectopically co-expressed in primary breast cancer tissues and determined that osteomimetic feature is obtained due to the osteoblast-like transformation of epithelial breast cancer cells that have undergone epithelial-mesenchymal transition (EMT) followed by bone morphogenetic protein-2 (BMP2) stimulation. Furthermore, we demonstrated that breast cancer cells that transformed into osteoblast-like cells with high expression of BRGs showed enhanced chemotaxis, adhesion, proliferation and multidrug resistance in an osteoblast-mimic bone microenvironment in vitro. During these processes, runt-related transcription factor 2 (RUNX2) functioned as a master mediator by suppressing or activating the transcription of BRGs that underlie the dynamic antagonism between the TGF-β/SMAD and BMP/SMAD signaling pathways in breast cancer cells. Our findings suggest a novel mechanism of osteomimicry formation that arises in primary breast tumors, which may explain the propensity of breast cancer to metastasize to the skeleton and contribute to potential strategies for predicting and targeting breast cancer bone metastasis and multidrug resistance.
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Digital electronic bone growth stimulator
DOE Office of Scientific and Technical Information (OSTI.GOV)
Kronberg, J.W.
1995-05-09
A device is described for stimulating bone tissue by applying a low level alternating current signal directly to the patient`s skin. A crystal oscillator, a binary divider chain and digital logic gates are used to generate the desired waveforms that reproduce the natural electrical characteristics found in bone tissue needed for stimulating bone growth and treating osteoporosis. The device, powered by a battery, contains a switch allowing selection of the correct waveform for bone growth stimulation or osteoporosis treatment so that, when attached to the skin of the patient using standard skin contact electrodes, the correct signal is communicated tomore » the underlying bone structures. 5 figs.« less
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Digital electronic bone growth stimulator
Kronberg, J.W.
1995-05-09
A device is described for stimulating bone tissue by applying a low level alternating current signal directly to the patient`s skin. A crystal oscillator, a binary divider chain and digital logic gates are used to generate the desired waveforms that reproduce the natural electrical characteristics found in bone tissue needed for stimulating bone growth and treating osteoporosis. The device, powered by a battery, contains a switch allowing selection of the correct waveform for bone growth stimulation or osteoporosis treatment so that, when attached to the skin of the patient using standard skin contact electrodes, the correct signal is communicated to the underlying bone structures. 5 figs.
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Clough, Bret H; Zeitouni, Suzanne; Krause, Ulf; Chaput, Christopher D; Cross, Lauren M; Gaharwar, Akhilesh K; Gregory, Carl A
2018-04-01
Non-union defects of bone are a major problem in orthopedics, especially for patients with a low healing capacity. Fixation devices and osteoconductive materials are used to provide a stable environment for osteogenesis and an osteogenic component such as autologous human bone marrow (hBM) is then used, but robust bone formation is contingent on the healing capacity of the patients. A safe and rapid procedure for improvement of the osteoanabolic properties of hBM is, therefore, sought after in the field of orthopedics, especially if it can be performed within the temporal limitations of the surgical procedure, with minimal manipulation, and at point-of-care. One way to achieve this goal is to stimulate canonical Wingless (cWnt) signaling in bone marrow-resident human mesenchymal stem cells (hMSCs), the presumptive precursors of osteoblasts in bone marrow. Herein, we report that the effects of cWnt stimulation can be achieved by transient (1-2 hours) exposure of osteoprogenitors to the GSK3β-inhibitor (2'Z,3'E)-6-bromoindirubin-3'-oxime (BIO) at a concentration of 800 nM. Very-rapid-exposure-to-BIO (VRE-BIO) on either hMSCs or whole hBM resulted in the long-term establishment of an osteogenic phenotype associated with accelerated alkaline phosphatase activity and enhanced transcription of the master regulator of osteogenesis, Runx2. When VRE-BIO treated hBM was tested in a rat spinal fusion model, VRE-BIO caused the formation of a denser, stiffer, fusion mass as compared with vehicle treated hBM. Collectively, these data indicate that the VRE-BIO procedure may represent a rapid, safe, and point-of-care strategy for the osteogenic enhancement of autologous hBM for use in clinical orthopedic procedures. Stem Cells Translational Medicine 2018;7:342-353. © 2018 The Authors Stem Cells Translational Medicine published by Wiley Periodicals, Inc. on behalf of AlphaMed Press.
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Clough, Bret H.; Zeitouni, Suzanne; Krause, Ulf; Chaput, Christopher D.; Cross, Lauren M.; Gaharwar, Akhilesh K.
2018-01-01
Abstract Non‐union defects of bone are a major problem in orthopedics, especially for patients with a low healing capacity. Fixation devices and osteoconductive materials are used to provide a stable environment for osteogenesis and an osteogenic component such as autologous human bone marrow (hBM) is then used, but robust bone formation is contingent on the healing capacity of the patients. A safe and rapid procedure for improvement of the osteoanabolic properties of hBM is, therefore, sought after in the field of orthopedics, especially if it can be performed within the temporal limitations of the surgical procedure, with minimal manipulation, and at point‐of‐care. One way to achieve this goal is to stimulate canonical Wingless (cWnt) signaling in bone marrow‐resident human mesenchymal stem cells (hMSCs), the presumptive precursors of osteoblasts in bone marrow. Herein, we report that the effects of cWnt stimulation can be achieved by transient (1–2 hours) exposure of osteoprogenitors to the GSK3β‐inhibitor (2′Z,3′E)‐6‐bromoindirubin‐3′‐oxime (BIO) at a concentration of 800 nM. Very‐rapid‐exposure‐to‐BIO (VRE‐BIO) on either hMSCs or whole hBM resulted in the long‐term establishment of an osteogenic phenotype associated with accelerated alkaline phosphatase activity and enhanced transcription of the master regulator of osteogenesis, Runx2. When VRE‐BIO treated hBM was tested in a rat spinal fusion model, VRE‐BIO caused the formation of a denser, stiffer, fusion mass as compared with vehicle treated hBM. Collectively, these data indicate that the VRE‐BIO procedure may represent a rapid, safe, and point‐of‐care strategy for the osteogenic enhancement of autologous hBM for use in clinical orthopedic procedures. stem cells translational medicine 2018;7:342–353 PMID:29405665
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Che Ahmad Tantowi, Nur Adeelah; Lau, Seng Fong; Mohamed, Suhaila
2018-05-28
Osteoporosis (OP) and osteoarthritis (OA) are debilitating musculoskeletal diseases of the elderly. Ficus deltoidea (FD) or mistletoe fig, a medicinal plant, was pre-clinically evaluated against OP- and OA-related bone alterations, in postmenopausal OA rat model. Thirty twelfth-week-old female rats were divided into groups (n = 6). Four groups were bilateral ovariectomized (OVX) and OA-induced by intra-articular monosodium iodoacetate (MIA) injection into the right knee joints. The Sham control and OVX-OA non-treated groups were given deionized water. The three other OVX-OA groups were orally administered daily with FD extract (200, 400 mg/kg) or diclofenac (5 mg/kg) for 4 weeks. The rats' bones and blood were evaluated for protein and mRNA expressions of osteoporosis and inflammatory indicators, and micro-CT computed tomography for bone microstructure. The non-treated OVX-OA rats developed severe OP bone loss and bone microstructural damage in the subchondral and metaphyseal regions, supported by reduced serum bone formation markers (osteocalcin, osteoprotegerin) and increased bone resorption markers (RANKL and CTX-I). The FD extract significantly (p < 0.05) mitigated these bone microstructural and biomarker changes by dose-dependently down-regulating pro-inflammatory NF-κβ, TNF-α, and IL-6 mRNA expressions. The FD extract demonstrated good anti-osteoporotic properties in this OP/OA preclinical model by stimulating bone formation and suppressing bone resorption via anti-inflammatory pathways. This is among the few reports relating the subchondral bone plate and trabecular thickening with the metaphyseal trabecular osteopenic bone loss under osteoporotic-osteoarthritis conditions, providing some insights on the debated inverse relationship between osteoporosis and osteoarthritis.
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Human Urine Derived Stem Cells in Combination with β-TCP Can Be Applied for Bone Regeneration.
Guan, Junjie; Zhang, Jieyuan; Li, Haiyan; Zhu, Zhenzhong; Guo, Shangchun; Niu, Xin; Wang, Yang; Zhang, Changqing
2015-01-01
Bone tissue engineering requires highly proliferative stem cells that are easy to isolate. Human urine stem cells (USCs) are abundant and can be easily harvested without using an invasive procedure. In addition, in our previous studies, USCs have been proved to be able to differentiate into osteoblasts, chondrocytes, and adipocytes. Therefore, USCs may have great potential and advantages to be applied as a cell source for tissue engineering. However, there are no published studies that describe the interactions between USCs and biomaterials and applications of USCs for bone tissue engineering. Therefore, the objective of the present study was to evaluate the interactions between USCs with a typical bone tissue engineering scaffold, beta-Tricalcium Phosphate (β-TCP), and to determine whether the USCs seeded onto β-TCP scaffold can promote bone regeneration in a segmental femoral defect of rats. Primary USCs were isolated from urine and seeded on β-TCP scaffolds. Results showed that USCs remained viable and proliferated within β-TCP. The osteogenic differentiation of USCs within the scaffolds was demonstrated by increased alkaline phosphatase activity and calcium content. Furthermore, β-TCP with adherent USCs (USCs/β-TCP) were implanted in a 6-mm critical size femoral defect of rats for 12 weeks. Bone regeneration was determined using X-ray, micro-CT, and histologic analyses. Results further demonstrated that USCs in the scaffolds could enhance new bone formation, which spanned bone defects in 5 out of 11 rats while β-TCP scaffold alone induced modest bone formation. The current study indicated that the USCs can be used as a cell source for bone tissue engineering as they are compatible with bone tissue engineering scaffolds and can stimulate the regeneration of bone in a critical size bone defect.
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Reinwald, Yvonne; El Haj, Alicia J
2018-03-01
Topographical and mechanical cues are vital for cell fate, tissue development in vivo, and to mimic the native cell growth environment in vitro. To date, the combinatory effect of mechanical and topographical cues as not been thoroughly investigated. This study investigates the effect of PCL nanofiber alignment and hydrostatic pressure on stem cell differentiation for bone tissue regeneration. Bone marrow-derived human mesenchymal stem cells were seeded onto standard tissue culture plastic and electrospun random and aligned nanofibers. These substrates were either cultured statically or subjected to intermittent hydrostatic pressure at 270 kPa, 1 Hz for 60 min daily over 21 days in osteogenic medium. Data revealed higher cell metabolic activities for all mechanically stimulated cell culture formats compared with non-stimulated controls; and random fibers compared with aligned fibers. Fiber orientation influenced cell morphology and patterns of calcium deposition. Significant up-regulation of Collagen-I, ALP, and Runx-2 were observed for random and aligned fibers following mechanical stimulation; highest levels of osteogenic markers were expressed when hydrostatic pressure was applied to random fibers. These results indicate that fiber alignment and hydrostatic pressure direct stem cell fate and are important stimulus for tissue regeneration. © 2017 The Authors Journal of Biomedical Materials Research Part A Published by Wiley Periodicals, Inc. J Biomed Mater Res Part A: A: 629-640, 2018. © 2017 The Authors Journal of Biomedical Materials Research Part A Published by Wiley Periodicals, Inc.
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El Haj, Alicia J.
2017-01-01
Abstract Topographical and mechanical cues are vital for cell fate, tissue development in vivo, and to mimic the native cell growth environment in vitro. To date, the combinatory effect of mechanical and topographical cues as not been thoroughly investigated. This study investigates the effect of PCL nanofiber alignment and hydrostatic pressure on stem cell differentiation for bone tissue regeneration. Bone marrow‐derived human mesenchymal stem cells were seeded onto standard tissue culture plastic and electrospun random and aligned nanofibers. These substrates were either cultured statically or subjected to intermittent hydrostatic pressure at 270 kPa, 1 Hz for 60 min daily over 21 days in osteogenic medium. Data revealed higher cell metabolic activities for all mechanically stimulated cell culture formats compared with non‐stimulated controls; and random fibers compared with aligned fibers. Fiber orientation influenced cell morphology and patterns of calcium deposition. Significant up‐regulation of Collagen‐I, ALP, and Runx‐2 were observed for random and aligned fibers following mechanical stimulation; highest levels of osteogenic markers were expressed when hydrostatic pressure was applied to random fibers. These results indicate that fiber alignment and hydrostatic pressure direct stem cell fate and are important stimulus for tissue regeneration. © 2017 The Authors Journal of Biomedical Materials Research Part A Published by Wiley Periodicals, Inc. J Biomed Mater Res Part A: A: 629–640, 2018. PMID:28984025
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BMP-2 and titanium particles synergistically activate osteoclast formation
Sun, S.X.; Guo, H.H.; Zhang, J.; Yu, B.; Sun, K.N.; Jin, Q.H.
2014-01-01
A previous study showed that BMP-2 (bone morphogenetic protein-2) and wear debris can separately support osteoclast formation induced by the receptor activator of NF-κB ligand (RANKL). However, the effect of BMP-2 on wear debris-induced osteoclast formation is unclear. In this study, we show that neither titanium particles nor BMP-2 can induce osteoclast formation in RAW 264.7 mouse leukemic monocyte macrophage cells but that BMP-2 synergizes with titanium particles to enhance osteoclast formation in the presence of RANKL, and that at a low concentration, BMP-2 has an optimal effect to stimulate the size and number of multinuclear osteoclasts, expression of osteoclast genes, and resorption area. Our data also clarify that the effects caused by the increase in BMP-2 on phosphorylated SMAD levels such as c-Fos expression increased throughout the early stages of osteoclastogenesis. BMP-2 and titanium particles stimulate the expression of p-JNK, p-P38, p-IkB, and P50 compared with the titanium group. These data suggested that BMP-2 may be a crucial factor in titanium particle-mediated osteoclast formation. PMID:24820069
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Electrical Polarization of Titanium Surfaces for the Enhancement of Osteoblast Differentiation
Gittens, Rolando A.; Olivares-Navarrete, Rene; Rettew, Robert; Butera, Robert J.; Alamgir, Faisal M.; Boyan, Barbara D.; Schwartz, Zvi
2014-01-01
Electrical stimulation has been used clinically to promote bone regeneration in cases of fractures with delayed union or nonunion, with several in vitro and in vivo reports suggesting its beneficial effects on bone formation. However, the use of electrical stimulation of titanium (Ti) implants to enhance osseointegration is less understood, in part because of the few in vitro models that attempt to represent the in vivo environment. In this article, the design of a new in vitro system that allows direct electrical stimulation of osteoblasts through their Ti substrates without the flow of exogenous currents through the media is presented, and the effect of applied electrical polarization on osteoblast differentiation and local factor production was evaluated. A custom-made polycarbonate tissue culture plate was designed to allow electrical connections directly underneath Ti disks placed inside the wells, which were supplied with electrical polarization ranging from 100 to 500 mV to stimulate MG63 osteoblasts. Our results show that electrical polarization applied directly through Ti substrates on which the cells are growing in the absence of applied electrical currents may increase osteoblast differentiation and local factor production in a voltage-dependent manner. PMID:23996899
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Antika, Lucia Dwi; Lee, Eun-Jung; Kim, Yun-Ho; Kang, Min-Kyung; Park, Sin-Hye; Kim, Dong Yeon; Oh, Hyeongjoo; Choi, Yean-Jung; Kang, Young-Hee
2017-11-01
Osteoporosis is one of the most prevalent forms of age-related bone diseases. Increased bone loss with advancing age has become a grave public health concern. This study examined whether phlorizin and phloretin, dihydrochalcones in apple peels, inhibited senile osteoporosis through enhancing osteoblastogenic bone formation in cell-based and aged mouse models. Submicromolar phloretin and phlorizin markedly stimulated osteoblast differentiation of MC3T3-E1 cells with increased transcription of Runx2 and osteocalcin. Senescence-accelerated resistant mouse strain prone-6 (SAMP6) mice were orally supplemented with 10 mg/kg phlorizin and phloretin daily for 12 weeks. Male senescence-accelerated resistant mouse strain R1 mice were employed as a nonosteoporotic age-matched control. Oral administration of ploretin and phorizin boosted bone mineralization in all the bones of femur, tibia and vertebra of SAMP6. In particular, phlorizin reduced serum RANKL/OPG ratio and diminished TRAP-positive osteoclasts in trabecular bones of SAMP6. Additionally, treating phlorizin to SAMP6 inhibited the osteoporotic resorption in distal femoral bones through up-regulating expression of BMP-2 and collagen-1 and decreasing production of matrix-degrading cathepsin K and MMP-9. Finally, phlorizin and phloretin antagonized GSK-3β induction and β-catenin phosphorylation in osteoblasts and aged mouse bones. Therefore, phlorizin and phloretin were potential therapeutic agents encumbering senile osteoporosis through promoting bone-forming osteoblastogenesis via modulation of GSK-3β/β-catenin-dependent signaling. Copyright © 2017 Elsevier Inc. All rights reserved.
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Castillo-Dalí, Gabriel; Batista-Cruzado, Antonio; López-Santos, Carmen; Rodríguez-González-Elipe, Agustín; Saffar, Jean-Louis; Lynch, Christopher D.; Gutiérrez-Pérez, José-Luis; Torres-Lagares, Daniel
2017-01-01
Background The use of cold plasmas may improve the surface roughness of poly(lactic-co-glycolic) acid (PLGA) membranes, which may stimulate the adhesion of osteogenic mediators and cells, thus accelerating the biodegradation of the barriers. Moreover, the incorporation of metallic-oxide particles to the surface of these membranes may enhance their osteoinductive capacity. Therefore, the aim of this paper was to evaluate the reliability of a new PLGA membrane after being treated with oxygen plasma (PO2) plus silicon dioxide (SiO2) layers for guided bone regeneration (GBR) processes. Material and Methods Circumferential bone defects (diameter: 11 mm; depth: 3 mm) were created on the top of eight experimentation rabbits’ skulls and were randomly covered with: (1) PLGA membranes (control), or (2) PLGA/PO2/SiO2 barriers. The animals were euthanized two months afterwards. A micromorphologic study was then performed using ROI (region of interest) colour analysis. Percentage of new bone formation, length of mineralised bone, concentration of osteoclasts, and intensity of ostheosynthetic activity were assessed and compared with those of the original bone tissue. The Kruskal-Wallis test was applied for between-group com Asignificance level of a=0.05 was considered. Results The PLGA/PO2/SiO2 membranes achieved the significantly highest new bone formation, length of mineralised bone, concentration of osteoclasts, and ostheosynthetic activity. The percentage of regenerated bone supplied by the new membranes was similar to that of the original bone tissue. Unlike what happened in the control group, PLGA/PO2/SiO2 membranes predominantly showed bone layers in advanced stages of formation. Conclusions The addition of SiO2 layers to PLGA membranes pre-treated with PO2 improves their bone-regeneration potential. Although further research is necessary to corroborate these conclusions in humans, this could be a promising strategy to rebuild the bone architecture prior to rehabilitate edentulous areas. Key words:Guided bone regeneration (GBR), poly(lactic-co-glycolic acid) (PLGA), membrane; oxygen plasma (PO2), nanocomposite, silicon dioxide layers. PMID:28160588
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Jing, Da; Luo, Erping; Cai, Jing; Tong, Shichao; Zhai, Mingming; Shen, Guanghao; Wang, Xin; Luo, Zhuojing
2016-09-01
Leptin, a major hormonal product of adipocytes, is involved in regulating appetite and energy metabolism. Substantial studies have revealed the anabolic actions of leptin on skeletons and bone cells both in vivo and in vitro. Growing evidence has substantiated that leptin receptor-deficient db/db mice exhibit decreased bone mass and impaired bone microstructure despite several conflicting results previously reported. We herein systematically investigated bone microarchitecture, mechanical strength, bone turnover and its potential molecular mechanisms in db/db mice. More importantly, we also explored an effective approach for increasing bone mass in leptin receptor-deficient animals in an easy and noninvasive manner. Our results show that deterioration of trabecular and cortical bone microarchitecture and decreases of skeletal mechanical strength-including maximum load, yield load, stiffness, energy, tissue-level modulus and hardness-in db/db mice were significantly ameliorated by 12-week, whole-body vibration (WBV) with 0.5 g, 45 Hz via micro-computed tomography (μCT), three-point bending, and nanoindentation examinations. Serum biochemical analysis shows that WBV significantly decreased serum tartrate-resistant acid phosphatase 5b (TRACP5b) and CTx-1 levels and also mitigated the reduction of serum osteocalcin (OCN) in db/db mice. Bone histomorphometric analysis confirmed that decreased bone formation-lower mineral apposition rate, bone formation rate, and osteoblast numbers in cancellous bone-in db/db mice were suppressed by WBV. Real-time PCR assays show that WBV mitigated the reductions of tibial alkaline phosphatase (ALP), OCN, Runt-related transcription factor 2 (RUNX2), type I collagen (COL1), BMP2, Wnt3a, Lrp6, and β-catenin mRNA expression, and prevented the increases of tibial sclerostin (SOST), RANK, RANKL, RANL/osteoprotegerin (OPG) gene levels in db/db mice. Our results show that WBV promoted bone quantity and quality in db/db mice with obvious anabolic and anticatabolic effects. This study not only enriches our basic knowledge about bone quality and bone turnover mechanisms in leptin receptor-deficient animals, but also advances our understanding of the skeletal sensitivity of leptin-resistant db/db mice in response to external mechanical stimulation. © 2016 American Society for Bone and Mineral Research. © 2016 American Society for Bone and Mineral Research.
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Makings of a brittle bone: Unexpected lessons from a low protein diet study of a mouse OI model
Mertz, E.L.; Makareeva, E.; Mirigian, L.S.; Koon, K.Y.; Perosky, J.E.; Kozloff, K.M.; Leikin, S.
2016-01-01
Glycine substitutions in type I collagen appear to cause osteogenesis imperfecta (OI) by disrupting folding of the triple helix, the structure of which requires Gly in every third position. It is less clear, however, whether the resulting bone malformations and fragility are caused by effects of intracellular accumulation of misfolded collagen on differentiation and function of osteoblasts, effects of secreted misfolded collagen on the function of bone matrix, or both. Here we describe a study originally conceived for testing how reducing intracellular accumulation of misfolded collagen would affect mice with a Gly610 to Cys substitution in the triple helical region of the α2(I) chain. To stimulate degradation of misfolded collagen by autophagy, we utilized a low protein diet. The diet had beneficial effects on osteoblast differentiation and bone matrix mineralization, but it also affected bone modeling and suppressed overall animal growth. Our more important observations, however, were not related to the diet. They revealed how altered osteoblast function and deficient bone formation by each cell caused by the G610C mutation combined with increased osteoblastogenesis might make the bone more brittle, all of which are common OI features. In G610C mice, increased bone formation surface compensated for reduced mineral apposition rate, resulting in normal cortical area and thickness at the cost of altering cortical modeling process, retaining woven bone, and reducing the ability of bone to absorb energy through plastic deformation. Reduced collagen and increased mineral density in extracellular matrix of lamellar bone compounded the problem, further reducing bone toughness. The latter observations might have particularly important implications for understanding OI pathophysiology and designing more effective therapeutic interventions. PMID:27039252
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Zhang, Ziyu; Yuan, Lang; Lee, Peter D; Jones, Eric; Jones, Julian R
2014-11-01
Bone augmentation implants are porous to allow cellular growth, bone formation and fixation. However, the design of the pores is currently based on simple empirical rules, such as minimum pore and interconnects sizes. We present a three-dimensional (3D) transient model of cellular growth based on the Navier-Stokes equations that simulates the body fluid flow and stimulation of bone precursor cellular growth, attachment, and proliferation as a function of local flow shear stress. The model's effectiveness is demonstrated for two additive manufactured (AM) titanium scaffold architectures. The results demonstrate that there is a complex interaction of flow rate and strut architecture, resulting in partially randomized structures having a preferential impact on stimulating cell migration in 3D porous structures for higher flow rates. This novel result demonstrates the potential new insights that can be gained via the modeling tool developed, and how the model can be used to perform what-if simulations to design AM structures to specific functional requirements. © 2014 Wiley Periodicals, Inc.
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Leali, Paolo Tranquilli; Balsano, Massimo; Maestretti, Gianluca; Brusoni, Matteo; Amorese, Veronica; Ciurlia, Emanuele; Andreozzi, Matteo; Caggiari, Gianfilippo; Doria, Carlo
2017-01-01
Summary Osteogenesis imperfecta (OI) is an hereditary disease characterized by low bone mass, increased bone fragility, short stature, and skeletal deformities, few treatment options are currently available. Neridronate is an amino-bisphosphonate, licensed in Italy for the treatment of OI and Paget’s disease of bone. A characteristic property of neridronate is that it can be administered both intravenously and intramuscularly, providing an useful system for administration in homecare. Neridronate appears to increase Bone Mineral Density (BMD) in adults with OI and reduces bone resorption by inhibition of osteoclastic activity. Teriparatide (recombinant 1–34 N terminal sequence of human parathyroid hormone) is the first anabolic agent approved for the treatment of patients with osteoporosis and has been reported to increase bone formation by stimulating osteoblast differentiation, osteoblast function, and survival. The results of this study showed a promising role of teriparatide in the therapy of OI type I. PMID:29263724
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Cohen, D. J.; Cheng, A.; Kahn, A.; Aviram, M.; Whitehead, A. J.; Hyzy, S. L.; Clohessy, R. M.; Boyan, B. D.; Schwartz, Z.
2016-01-01
Custom devices supporting bone regeneration and implant placement are needed for edentulous patients with large mandibular deficiencies where endosteal implantation is not possible. We developed a novel subperiosteal titanium-aluminum-vanadium bone onlay device produced by additive manufacturing (AM) and post-fabrication osteogenic micro-/nano-scale surface texture modification. Human osteoblasts produced osteogenic and angiogenic factors when grown on laser-sintered nano-/micro-textured surfaces compared to smooth surfaces. Surface-processed constructs caused higher bone-to-implant contact, vertical bone growth into disk pores (microCT and histomorphometry), and mechanical pull-out force at 5 and 10 w on rat calvaria compared to non surface-modified constructs, even when pre-treating the bone to stimulate osteogenesis. Surface-modified wrap-implants placed around rabbit tibias osseointegrated by 6 w. Finally, patient-specific constructs designed to support dental implants produced via AM and surface-processing were implanted on edentulous mandibular bone. 3 and 8 month post-operative images showed new bone formation and osseointegration of the device and indicated stability of the dental implants. PMID:26854193
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Cohen, D J; Cheng, A; Kahn, A; Aviram, M; Whitehead, A J; Hyzy, S L; Clohessy, R M; Boyan, B D; Schwartz, Z
2016-02-08
Custom devices supporting bone regeneration and implant placement are needed for edentulous patients with large mandibular deficiencies where endosteal implantation is not possible. We developed a novel subperiosteal titanium-aluminum-vanadium bone onlay device produced by additive manufacturing (AM) and post-fabrication osteogenic micro-/nano-scale surface texture modification. Human osteoblasts produced osteogenic and angiogenic factors when grown on laser-sintered nano-/micro-textured surfaces compared to smooth surfaces. Surface-processed constructs caused higher bone-to-implant contact, vertical bone growth into disk pores (microCT and histomorphometry), and mechanical pull-out force at 5 and 10 w on rat calvaria compared to non surface-modified constructs, even when pre-treating the bone to stimulate osteogenesis. Surface-modified wrap-implants placed around rabbit tibias osseointegrated by 6 w. Finally, patient-specific constructs designed to support dental implants produced via AM and surface-processing were implanted on edentulous mandibular bone. 3 and 8 month post-operative images showed new bone formation and osseointegration of the device and indicated stability of the dental implants.
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Yao, Shaomian; Prpic, Veronica; Pan, Fenghui; Wise, Gary E.
2011-01-01
The dental follicle appears to regulate both the alveolar bone resorption and bone formation needed for tooth eruption. Tumor necrosis factor-alpha ( TNF-α) gene expression is maximally upregulated at postnatal day 9 in the rat dental follicle of the 1st mandibular molar, a time that correlates with rapid bone growth at the base of the tooth crypt, as well as a minor burst of osteoclastogenesis. TNF-α expression is correlated with the expression of bone morphogenetic protein-2 (BMP-2), a molecule expressed in the dental follicle that can promote bone formation. Because BMP-2 signaling may be augmented by bone morphogenetic protein-3 (BMP-3), it was the objective of this study to determine 1) if the dental follicle expresses BMP-3 and 2) if TNF-α stimulates the dental follicle cells to express BMP-2 and BMP-3. Dental follicles were collected from different postnatal ages of rat pups. Dental follicle cells were incubated with TNF-α to study its dosage and time-course effects on gene expression of BMP-2 and BMP-3, as determined by real-time RT-PCR. Next, immunostaining was conducted to confirm if the protein was synthesized and ELISA of the conditioned medium was conducted to determine if BMP-2 was secreted. We found that BMP-3 expression is correlated with the expression of TNF-α in the dental follicle and TNF-α significantly increased BMP-2 and BMP-3 expression in vitro. Immunostaining and ELISA showed that BMP-2 and BMP-3 were synthesized and secreted. This study suggests that TNF-α can upregulate the expression of bone formation genes that may be needed for tooth eruption. PMID:20067418
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Nishida, Erika; Miyaji, Hirofumi; Kato, Akihito; Takita, Hiroko; Iwanaga, Toshihiko; Momose, Takehito; Ogawa, Kosuke; Murakami, Shusuke; Sugaya, Tsutomu; Kawanami, Masamitsu
2016-01-01
Graphene oxide (GO) consisting of a carbon monolayer has been widely investigated for tissue engineering platforms because of its unique properties. For this study, we fabricated a GO-applied scaffold and assessed the cellular and tissue behaviors in the scaffold. A preclinical test was conducted to ascertain whether the GO scaffold promoted bone induction in dog tooth extraction sockets. For this study, GO scaffolds were prepared by coating the surface of a collagen sponge scaffold with 0.1 and 1 µg/mL GO dispersion. Scaffolds were characterized using scanning electron microscopy (SEM), physical testing, cell seeding, and rat subcutaneous implant testing. Then a GO scaffold was implanted into a dog tooth extraction socket. Histological observations were made at 2 weeks postsurgery. SEM observations show that GO attached to the surface of collagen scaffold struts. The GO scaffold exhibited an interconnected structure resembling that of control subjects. GO application improved the physical strength, enzyme resistance, and adsorption of calcium and proteins. Cytocompatibility tests showed that GO application significantly increased osteoblastic MC3T3-E1 cell proliferation. In addition, an assessment of rat subcutaneous tissue response revealed that implantation of 1 µg/mL GO scaffold stimulated cellular ingrowth behavior, suggesting that the GO scaffold exhibited good biocompatibility. The tissue ingrowth area and DNA contents of 1 µg/mL GO scaffold were, respectively, approximately 2.5-fold and 1.4-fold greater than those of the control. Particularly, the infiltration of ED2-positive (M2) macrophages and blood vessels were prominent in the GO scaffold. Dog bone-formation tests showed that 1 µg/mL GO scaffold implantation enhanced bone formation. New bone formation following GO scaffold implantation was enhanced fivefold compared to that in control subjects. These results suggest that GO was biocompatible and had high bone-formation capability for the scaffold. The GO scaffold is expected to be beneficial for bone tissue engineering therapy.
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Jahanbin, Arezoo; Rashed, Roozbeh; Alamdari, Daryoush Hamidi; Koohestanian, Niloufar; Ezzati, Atefeh; Kazemian, Mojgan; Saghafi, Shadi; Raisolsadat, Mohammad Ali
2016-04-01
The use of cell-based therapies represents one of the most advanced methods for enhancing the regenerative response in craniofacial abnormalities. The main aim of this study was to evaluate the regenerative potential of human dental pulp stem cells, isolated from deciduous teeth, for reconstructing maxillary alveolar defects in Wistar rats. Human deciduous dental pulp stem cells were isolated and stimulated to differentiate into osteoblasts in culture media. Maxillary alveolar defects were created in 60 Wistar rats by a surgical procedure. Then, on the basis of the type of graft used to repair the bone defect, the rats were divided into 6 equal groups: groups 1 and 2, transplantation of iliac bone graft; groups 3 and 4, transplantation of stem cells derived from deciduous dental pulp in addition to collagen matrix; groups 5 and 6, transplantation of just collagen matrix. Then, fetal bone formation, granulation tissue, fibrous tissue, and inflammatory tissue were evaluated by hematoxylin-eosin staining at 1 month (groups 1, 3, and 5) and 2 months (groups 2, 4, and 6) after surgery, and data were analyzed and compared using the Fisher exact test. Maximum fetal bone formation occurred in group 2, in which iliac bone graft was inserted into the defect area for 2 months; there also were significant differences among the groups for bone formation (P = .009). In the 1-month groups, there were no significant differences between the control and stem cell-plus-scaffold groups. There were significant differences between the 2-month groups for fetal bone formation only between the control and scaffold groups (P = .026). The study showed that human dental pulp stem cells are an additional cell resource for repairing maxillary alveolar defects in rats and constitute a promising model for reconstruction of human maxillary alveolar defects in patients with cleft lip and palate. Copyright © 2016 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.
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Fan, Huailing; Ji, Feng; Lin, Ying; Zhang, Mulan; Qin, Wei; Zhou, Qi; Wu, Qiang
2016-03-01
The present study aimed to investigate the effect of electroacupuncture stimulation at CV4 (also termed Guanyuan) on femoral osteocalcin also termed bone gla protein (BGP), alkaline phosphatase (ALP), bone mineral density (BMD) and biomechanics, as well as the Wnt‑β‑catenin signaling pathway in rats with postmenopausal osteoporosis. Female Sprague‑Dawley rats (4.5‑months old) were randomly divided into sham, Ovx, CV4 and mock groups (n=10/group). With the exception of those in the sham group, the rats were ovariectomized to induce postmenopausal osteoporosis. The rats in the CV4 and mock groups were given electroacupuncture at CV4 and non‑acupoint, respectively. The rats in the Ovx model and sham groups underwent identical fixing procedures, but did not undergo electroacupuncture. Following treatment, hematoxylin and eosin staining was used to observe morphological changes in the left femoral trabecular bone, and a three‑point‑bending test was used to analyze femur biomechanics and determine the BMD. In addition, an enzyme‑linked immunosorbent assay was used to measure the serum levels of ALP/BGP and reverse transcription‑quantitative polymerase chain reaction was used detect the expression levels of Wnt3a, β‑catenin and Runx2. In the present study, it was demonstrated that electroacupuncture at CV4 significantly improved the osteoporotic morphological changes that occurred in the ovariectomized rats, increased serum ALP and BGP levels, enhanced the maximum and fracture loads, increased BMD (P<0.01), and activated the Wnt‑β‑catenin signaling pathway. These findings demonstrated that electroacupuncture stimulation at CV4 affected bone formation and promoted bone metabolism in rats with postmenopausal osteoporosis, possibly by activating the Wnt‑β‑catenin signaling pathway.
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FAN, HUAILING; JI, FENG; LIN, YING; ZHANG, MULAN; QIN, WEI; ZHOU, QI; WU, QIANG
2016-01-01
The present study aimed to investigate the effect of electroacupuncture stimulation at CV4 (also termed Guanyuan) on femoral osteocalcin also termed bone gla protein (BGP), alkaline phosphatase (ALP), bone mineral density (BMD) and biomechanics, as well as the Wnt-β-catenin signaling pathway in rats with postmenopausal osteoporosis. Female Sprague-Dawley rats (4.5-months old) were randomly divided into sham, Ovx, CV4 and mock groups (n=10/group). With the exception of those in the sham group, the rats were ovariectomized to induce postmenopausal osteoporosis. The rats in the CV4 and mock groups were given electroacupuncture at CV4 and non-acupoint, respectively. The rats in the Ovx model and sham groups underwent identical fixing procedures, but did not undergo electroacupuncture. Following treatment, hematoxylin and eosin staining was used to observe morphological changes in the left femoral trabecular bone, and a three-point-bending test was used to analyze femur biomechanics and determine the BMD. In addition, an enzyme-linked immunosorbent assay was used to measure the serum levels of ALP/BGP and reverse transcription-quantitative polymerase chain reaction was used detect the expression levels of Wnt3a, β-catenin and Runx2. In the present study, it was demonstrated that electroacupuncture at CV4 significantly improved the osteoporotic morphological changes that occurred in the ovariectomized rats, increased serum ALP and BGP levels, enhanced the maximum and fracture loads, increased BMD (P<0.01), and activated the Wnt-β-catenin signaling pathway. These findings demonstrated that electroacupuncture stimulation at CV4 affected bone formation and promoted bone metabolism in rats with postmenopausal osteoporosis, possibly by activating the Wnt-β-catenin signaling pathway. PMID:26846191
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Zhang, Kun; Niu, Liang-Chen; Yuan, Fu-Jie; Liu, Shen-Peng
2017-08-25
Traditional Chinese medicine is widely used in the treatment of fractures, osteoporosis, other bone related diseases for thousands of years. There are many animal experiments and clinical trials demonstrating that the traditional Chinese medicine such as epimedium, Drynaria and other traditional Chinese medicine can stimulate bone regeneration and inhibit bone resorption, accelerating the fracture healing. In recent years many cell experiments have shown that these herbal ingredients up-regulated the expression of intracellular osteogenic transcription factors and osteogenic related genes, and then induced osteoblastic differentiation and stimulated the proliferation of osteoblasts, bone nodule formation and matrix mineralization. Meanwhile these herbal ingredients up-regulated the expression of intracellular osteoclastic transcription factors and osteoclast related genes, inhibited osteoclast differentiation and bone resorption of osteoclasts. In addition, intracellular signaling pathways regulated these herbal ingredients by might be involved in the above effects. We can have a conclusion that the genes expression regulated by transcription factors in pre-osteoblast and pre-osteoclast and these signaling pathways are the major molecular mechanisms and research hotspots of traditional Chinese medicine in promoting fracture healing. Based on these molecular mechanisms to review, this review provides not only the foundation for the study of traditional Chinese medicine in promoting fracture healing, but also the basis for clinical treatment of fracture. Copyright© 2017 by the China Journal of Orthopaedics and Traumatology Press.
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Hess, Ricarda; Jaeschke, Anna; Neubert, Holger; Hintze, Vera; Moeller, Stephanie; Schnabelrauch, Matthias; Wiesmann, Hans-Peter; Hart, David A; Scharnweber, Dieter
2012-12-01
In vivo, bone formation is a complex, tightly regulated process, influenced by multiple biochemical and physical factors. To develop a vital bone tissue engineering construct, all of these individual components have to be considered and integrated to gain an in vivo-like stimulation of target cells. The purpose of the present studies was to investigate the synergistic role of defined biochemical and physical microenvironments with respect to osteogenic differentiation of human mesenchymal stem cells (MSCs). Biochemical microenvironments have been designed using artificial extracellular matrices (aECMs), containing collagen I (coll) and glycosaminoglycans (GAGs) like chondroitin sulfate (CS), or a high-sulfated hyaluronan derivative (sHya), formulated as coatings on three-dimensional poly(caprolactone-co-lactide) (PCL) scaffolds. As part of the physical microenvironment, cells were exposed to pulsed electric fields via transformer-like coupling (TC). Results showed that aECM containing sHya enhanced osteogenic differentiation represented by increases in ALP activity and gene-expression (RT-qPCR) of several bone-related proteins (RUNX-2, ALP, OPN). Electric field stimulation alone did not influence cell proliferation, but osteogenic differentiation was enhanced if osteogenic supplements were provided, showing synergistic effects by the combination of sHya and electric fields. These results will improve the understanding of bone regeneration processes and support the development of effective tissue engineered bone constructs. Copyright © 2012 Elsevier Ltd. All rights reserved.
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Lee, Jongsung; Nho, Youn Hwa; Yun, Seok Kyun; Hwang, Young Sun
2017-02-16
The fruit of the Terminalia chebula tree has been widely used for the treatment of various disorders. Its anti-diabetic, anti-mutagenic, anti-oxidant, anti-bacterial, anti-fungal, and anti-viral effects have been studied. Dental plaque bacteria (DPB) are intimately associated with gingivitis and periodontitis. In the quest for materials that will prove useful in the treatment and prevention of periodontal disease, we investigated the preventive effects of an ethanol extract of Terminalia chebula (EETC) on DPB-induced inflammation and bone resorption. The anti-bacterial effect of EETC was analyzed using the disc diffusion method. The anti-inflammatory effect of EETC was determined by molecular biological analysis of the DPB-mediated culture cells. Prevention of osteoclastic bone resorption by EETC was explored using osteoclast formation and pit formation assays. EETC suppressed the growth of oral bacteria and reduced the induction of inflammatory cytokines and proteases, abolishing the expression of PGE2 and COX-2 and inhibiting matrix damage. By stimulating the DPB-derived lipopolysaccharides, EETC inhibited both osteoclast formation in osteoclast precursors and RANKL expression in osteoblasts, thereby contributing to the prevention of bone resorption. EETC may be a beneficial supplement to help prevent DPB-mediated periodontal disease.
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NASA Technical Reports Server (NTRS)
Bikle, Daniel D.; Sakata, Takeshi; Leary, Colin; Elalieh, Hashem; Ginzinger, David; Rosen, Clifford J.; Beamer, Wesley; Majumdar, Sharmila; Halloran, Bernard P.
2002-01-01
Parathyroid hormone (PTH) is a potent anabolic agent for bone, but the mechanism(s) by which it works remains imperfectly understood. Previous studies have indicated that PTH stimulates insulin-like growth factor (IGF) I production, but it remains uncertain whether IGF-I mediates some or all of the skeletal actions of PTH. To address this question, we examined the skeletal response to PTH in IGF-I-deficient (knockout [k/o]) mice. These mice and their normal littermates (NLMs) were given daily injections of PTH (80 microg/kg) or vehicle for 2 weeks after which their tibias were examined for fat-free weight (FFW), bone mineral content, bone structure, and bone formation rate (BFR), and their femurs were assessed for mRNA levels of osteoblast differentiation markers. In wild-type mice, PTH increased FFW, periosteal BFR, and cortical thickness (C.Th) of the proximal tibia while reducing trabecular bone volume (BV); these responses were not seen in the k/o mice. The k/o mice had normal mRNA levels of the PTH receptor and increased mRNA levels of the IGF-I receptor but markedly reduced basal mRNA levels of the osteoblast markers. Surprisingly, these mRNAs in the k/o bones increased several-fold more in response to PTH than the mRNAs in the bones from their wild-type littermates. These results indicate that IGF-I is required for the anabolic actions of PTH on bone formation, but the defect lies distal to the initial response of the osteoblast to PTH.
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ATOMIC ENERGY COMMISSION PROGRESS REPORT ON BONE RESEARCH , 1960-1961
DOE Office of Scientific and Technical Information (OSTI.GOV)
None
1962-10-31
A review of osteoporosis concepts is presented. Activities in an experimental program to study osteoporosis by examining mineral metabolism in bone and by examining bone composition and density are reported. Sr/sup 85/ was administered to seven osteoporotic patients as a tracer for skeletal mineral metabolism. The activity levels in the blood and the excretion rate were measured. From these data the accretion rate and the diffusible component volume were calculated. It was found that the accretion rate was not increased in any case. The size of the diffusible component was normal in six patients and reduced in one. Concurrent experimentsmore » with estrogen administration were conducted. Over-all results indicate that in osteoporosis, the rate of bone accretion is never elevated and an effect of estrogen administration was the decrease of bone resorption rather than stimulation of bone formation. In studies of skeletal metabolism, the kinetics of Sr/sup 85/ metabolism was compared in normal subjects and patients with skeletal disorders. Various aspects of the results are analyzed and it is concluded that values obtained by kinetic studies appear to be quantitative, reproducible, and to correlate with presently established information on alterations of bone metabolism in systemic deseases. In studies of peripheral circulation and bone growth, I/sup 131tagged human serum albumin was injected in animals. The investigation was conducted to determine blood volumne turnover rate in extremities, to correlate changes in this rate with fractures and bone disorders, and to examine the method for use in evaluation of circulation under certain pathological conditions. Data and findings are included. Data are also included on in vitro mobilization of Sr/ sup 85/ during bone formation and bone density studies. (J.R.D.)« less
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Inorganic materials for bone repair or replacement applications.
Hertz, Audrey; Bruce, Ian J
2007-12-01
In recent years, excipient systems have been used increasingly in biomedicine in reconstructive and replacement surgery, as bone cements, drug-delivery vehicles and contrast agents. Particularly, interest has been growing in the development and application of controlled pore inorganic ceramic materials for use in bone-replacement and bone-repair roles and, in this context, attention has been focused on calcium-phosphate, bioactive glasses and SiO2- and TiO2-based materials. It has been shown that inorganic materials that most closely mimic bone structure and surface chemistry most closely function best in bone replacement/repair and, in particular, if a substance possesses a macroporous structure (pores and interconnections >100 microm diameter), then cell infiltration, bone growth and vascularization can all be promoted. The surface roughness and micro/mesoporosity of a material have also been observed to significantly influence its ability to promote apatite nucleation and cell attachment significantly. Pores (where present) can also be packed with pharmaceuticals and biomolecules (e.g., bone morphogenetic proteins [BMPs], which can stimulate bone formation). Finally, the most bio-efficient - in terms of collagen formation and apatite nucleation - materials are those that are able to provide soluble mineralizing species (Si, Ca, PO(4)) at their implant sites and/or are doped or have been surface-activated with specific functional groups. This article presents the context and latest advances in the field of bone-repair materials, especially with respect to the development of bioactive glasses and micro/mesoporous and macroporous inorganic scaffolds. It deals with the possible methods of preparing porous pure/doped or functionalized silicas or their composites, the studies that have been undertaken to evaluate their abilities to act as bone repair scaffolds and also presents future directions for work in that context.
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Quade, Mandy; Knaack, Sven; Akkineni, Ashwini Rahul; Gabrielyan, Anastasia; Lode, Anja; Rösen-Wolff, Angela; Gelinsky, Michael
2017-08-01
Tissue engineering, the application of stem and progenitor cells in combination with an engineered extracellular matrix, is a promising strategy for bone regeneration. However, its success is limited by the lack of vascularization after implantation. The concept of in situ tissue engineering envisages the recruitment of cells necessary for tissue regeneration from the host environment foregoing ex vivo cell seeding of the scaffold. In this study, we developed a novel scaffold system for enhanced cell attraction, which is based on biomimetic mineralized collagen scaffolds equipped with a central biopolymer depot loaded with chemotactic agents. In humid milieu, as after implantation, the signaling factors are expected to slowly diffuse out of the central depot forming a gradient that stimulates directed cell migration toward the scaffold center. Heparin, hyaluronic acid, and alginate have been shown to be capable of depot formation. By using vascular endothelial growth factor (VEGF) as model factor, it was demonstrated that the release kinetics can be adjusted by varying the depot composition. While alginate and hyaluronic acid are able to reduce the initial burst and prolong the release of VEGF, the addition of heparin led to a much stronger retention that resulted in an almost linear release over 28 days. The biological activity of released VEGF was proven for all variants using an endothelial cell proliferation assay. Furthermore, migration experiments with endothelial cells revealed a relationship between the degree of VEGF retention and migration distance: cells invaded deepest in scaffolds containing a heparin-based depot indicating that the formation of a steep gradient is crucial for cell attraction. In conclusion, this novel in situ tissue engineering approach, specifically designed to recruit and accommodate endogenous cells upon implantation, appeared highly promising to stimulate cell invasion, which in turn would promote vascularization and finally new bone formation.
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Imbalanced expression of RANKL and osteoprotegerin mRNA in pannus tissue of rheumatoid arthritis.
Ainola, M; Mandelin, J; Liljeström, M; Konttinen, Y T; Salo, J
2008-01-01
To test if the pannus tissue is characterized by a high receptor activator of nuclear factor kappaB ligand to osteoprotegerin (RANKL:OPG) ratio, which could explain local osteoclastogenesis and formation of bony erosions. Messenger RNA and protein expressions of RANKL and OPG in rheumatoid and osteoarthritic tissue samples were measured using quantitative real-time RT-PCR and Western blot/densitometry. Pannus and synovitis fibroblasts explanted from tissue samples were cultured in vitro without and with TNF-alpha, IL-1Beta or IL-17 and analyzed quantitatively for RANKL expression. The ability of pannus fibroblasts to induce formation of multinuclear osteoclast-like cells from human monocytes, with macrophage-colony stimulating factor (M-CSF) but without RANKL added, was tested. Histochemical staining was used to assess the eventual presence of RANKL and tartrate resistant acid phosphatase positive osteoclast-like cells at the pannus-bone interface. RANKL:OPG ratios of messenger RNA (p<0.05) and protein level were high in pannus (2.06+/-0.73 and 2.2+/-0.65) compared to rheumatoid (0.62+/-0.13 and 1.31+/-0.69) and osteoarthritis (0.62+/-0.32 and 0.52+/-0.16) synovial membranes. Resting and stimulated (p dependent on the cytokine used) pannus fibroblasts produced RANKL in excess (p=0.0005) and unstimulated pannus fibroblasts also effectively induced osteoclast-like cell formation from monocytes in vitro without any exogenous RANKL added. Compatible with these findings, multinuclear osteoclasts-like cells were frequent in the fibroblast- and macrophage-rich pannus tissue at the soft tissue-to-bone interface. The high RANKL:OPG ratio, together with close fibroblast-to-monocyte contacts in pannus tissue, probably favor local generation of bone resorbing osteoclasts at the site of erosion in rheumatoid arthritis.
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Modulation of bone remodeling via mechanically activated ion channels
NASA Technical Reports Server (NTRS)
Duncan, Randall L. (Principal Investigator)
1996-01-01
A critical factor in the maintenance of bone mass is the physical forces imposed upon the skeleton. Removal of these forces, such as in a weightless environment, results in a rapid loss of bone, whereas application of exogenous mechanical strain has been shown to increase bone formation. Numerous flight and ground-based experiments indicate that the osteoblast is the key bone cell influenced by mechanical stimulation. Aside from early transient fluctuations in response to unloading, osteoclast number and activity seem unaffected by removal of strain. However, bone formation is drastically reduced in weightlessness and osteoblasts respond to mechanical strain with an increase in the activity of a number of second messenger pathways resulting in increased anabolic activity. Unfortunately, the mechanism by which the osteoblast converts physical stimuli into a biochemical message, a process we have termed biochemical coupling, remains elusive. Prior to the application of this grant, we had characterized a mechanosensitive, cation nonselective channel (SA-cat) in osteoblast-like osteosarcoma cells that we proposed is the initial signalling mechanism for mechanotransduction. During the execution of this grant, we have made considerable progress to further characterize this channel as well as to determine its role in the osteoblastic response to mechanical strain. To achieve these goals, we combined electrophysiologic techniques with cellular and molecular biology methods to examine the role of these channels in the normal function of the osteoblast in vitro.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Stoner, R.D.; Bond, V.P.
1963-01-14
Immunological competence of immunized mouse bone marrow, spleen, lymph node, and thymus cells was demonstrated when specific recall tetanus antitoxin responses were elicited after transfer of these cells to isologous irradiated mice or rats. Lesser amounts of antibody were obtained as the genetic strain distance was increased between the relation of donor and host in the parental to F/sub 1/ and in the homologous combination within the same species. It was not possible in the heterologous situation to elicit significant amounts of antibody from rat bone marrow and other lymphoid cells following their transplantation into irradiated mice. Minimal but notmore » significant antibody responses were elicited from cells obtained from immunized rat spleen and thymus tissue. In a few experiments, it was possible to elicit antibody formation from a buffy coat suspension of circulating white cells following their transfer to irradiated recipients. Isologous nonimmunized bone marrow did not stimulate or hasten recovery of the ability to eiicit secondary antibody responses in previously immunized irradiated mice. The capacity to elicit primary antibody responses to tetanus toxoid was depressed in parental-bone-marrow-protected F/sub 1/ mice when these chimeras exhibited varying degrees of secondary disease. The depression of primary antibody responses in irradiated F/sub 1/ mice given parental bone marrow provides evidence for a donor mediated immunological depression of antibody synthesis by host-lymphoid tissues. (auth)« less
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Osteoblast and osteocyte: games without frontiers.
Capulli, Mattia; Paone, Riccardo; Rucci, Nadia
2014-11-01
The portrait of osteoblasts and osteocytes has been subjected to a revision, since a large body of evidence is attributing these cells amazing roles both inside and outside the bone. The osteoblast, long confined to its bone building function, is actually a very eclectic cell, actively regulating osteoclast formation and function as well as hematopoietic stem cells homeostasis. It is also an endocrine cell, affecting energy metabolism, male fertility and cognition through the release of osteocalcin, a perfect definition-fitting hormone in its uncarboxylated state. As for the osteocytes, many evidence shows that they do not merely represent the final destination of the osteoblasts, but they are instead very active cells that, besides a mechanosensorial function, actively contribute to the bone remodelling by regulating bone formation and resorption. The regulation is exerted by the production of sclerostin (SOST), which in turn inhibits osteoblast differentiation by blocking Wnt/beta-catenin pathway. At the same time, osteocytes influence bone resorption both indirectly, by producing RANKL, which stimulates osteoclastogenesis, and directly by means of a local osteolysis, which is observed especially under pathological conditions. The great versatility of both these cells reflects the complexity of the bone tissue, which has not only a structural role, but influences and is influenced by different organs, taking part in homeostatic and adaptive responses affecting the whole organism. Copyright © 2014. Published by Elsevier Inc.
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Chang, Jia; Liu, Fei; Lee, Min; Wu, Benjamin; Ting, Kang; Zara, Janette N.; Soo, Chia; Al Hezaimi, Khalid; Zou, Weiping; Chen, Xiaohong; Mooney, David J.; Wang, Cun-Yu
2013-01-01
Mesenchymal stem cell (MSC)-based transplantation is a promising therapeutic approach for bone regeneration and repair. In the realm of therapeutic bone regeneration, the defect or injured tissues are frequently inflamed with an abnormal expression of inflammatory mediators. Growing evidence suggests that proinflammatory cytokines inhibit osteogenic differentiation and bone formation. Thus, for successful MSC-mediated repair, it is important to overcome the inflammation-mediated inhibition of tissue regeneration. In this study, using genetic and chemical approaches, we found that proinflammatory cytokines TNF and IL-17 stimulated IκB kinase (IKK)–NF-κB and impaired osteogenic differentiation of MSCs. In contrast, the inhibition of IKK–NF-κB significantly enhanced MSC-mediated bone formation. Mechanistically, we found that IKK–NF-κB activation promoted β-catenin ubiquitination and degradation through induction of Smurf1 and Smurf2. To translate our basic findings to potential clinic applications, we showed that the IKK small molecule inhibitor, IKKVI, enhanced osteogenic differentiation of MSCs. More importantly, the delivery of IKKVI promoted MSC-mediated craniofacial bone regeneration and repair in vivo. Considering the well established role of NF-κB in inflammation and infection, our results suggest that targeting IKK–NF-κB may have dual benefits in enhancing bone regeneration and repair and inhibiting inflammation, and this concept may also have applicability in many other tissue regeneration situations. PMID:23690607
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NASA Technical Reports Server (NTRS)
Rubin, C.; Zhi, J.; Xu, G.; Cute, M.; McLeod, K.; Hadjiargyrou, M.
1999-01-01
The National Research Council's report entitled: A Strategy for Space Biology and Medical Science, highlighted several areas of fundamental scientific investigation which must be addressed to make long-term space exploration not only feasible, but safe. This "Goldberg Strategy," as well as several subsequent reports published by the NRC's Space Studies Board (e.g., Assessment of Programs in Space Biology and Medicine, Smith et. al., 1991), suggests that the principal hurdle to man's extended presence in space is the osteopenia which parallels reduced gravity. Ironically, the most significant risk to the skeleton may only be realized on return to normal gravitational fields, and full recovery of bone mass may never occur. Effective counter-measures to this microgravity induced bone loss are thus essential. Considering the similarities of space and aging induced osteopenia, an indisputable benefit of such a prophylaxis would be its potential as a treatment for the bone loss which plagues over 25 million people in the U.S. The osteogenic potential of mechanical strain is strongly frequency dependent, with sensitivity increasing up through at least 60 Hz (cycles per second). One hundred seconds per day of a 1 Hz cyclic loading will inhibit disuse osteopenia only if sufficient in magnitude to engender 1000 microstrain (mu(epsilon)) in the tissue. When loading is applied at 30 Hz, however, mechanical strains on the order of 5O mu(epsilon) (approx. 1% of the peak strains which occur in bone during vigorous functional activity), can stimulate bone formation in a duration dependent manner. In longer term animal studies, strains of less than 10 mu(epsilon), induced non-invasively via a whole body vibration, will stimulate bone formation on the surfaces of trabeculae, increase bone density, and improve strength. Finally, preliminary results from a double blind prospective clinical trial shows promise in inhibiting the bone loss which parallels the menopause. Based on these observations, we propose that these high frequency, low magnitude, mechanical strains effectively serve as a "surrogate" for musculoskeletal ground reaction forces, and thus represent an ideal countermeasure to the osteopenia which parallels microgravity conditions. The specific goal of this NASA funded work is to identify genes in bone upregulated by disuse, and to determine the efficacy of an osteogenic mechanical stimulus to downregulate their expression.
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Compositos CNTs/bioceramico para a estimulacao eletrica ossea in situ
NASA Astrophysics Data System (ADS)
Mata, Diogo Miguel Rodrigues Marinho da
The present thesis aims to develop a biocompatible and electroconductor bone graft containing carbon nanotubes (CNTs) that allows the in situ regeneration of bone cells by applying pulsed external electrical stimuli. The CNTs were produced by chemical vapor deposition (CVD) by a semi-continuous method with a yield of 500 mg/day. The deposition parameters were optimised to obtain high pure CNTs 99.96% with controlled morphologies, fundamental requisites for the biomedical application under study. The chemical functionalisation of CNTs was also optimised to maximise their processability and biocompatibility. The CNTs were functionalised by the Diels-Alder cycloaddition of 1,3-butadiene. The biological behaviour of the functionalised CNTs was evaluated in vitro with the osteoblastic cells line MG63 and in vivo, by subcutaneous implantation in rats. The materials did not induce an expressed inflammatory response, but the functionalised CNTs showed a superior in vitro and in vivo biocompatibility than the non-functionalised ones. Composites of ceramic matrix, of bioglass (Glass) and hydroxyapatite (HA), reinforced with carbon nanotubes (CNT/Glass/HA) were processed by a wet approach. The incorporation of just 4.4 vol% of CNTs allowed the increase of 10 orders of magnitude of the electrical conductivity of the matrix. In vitro studies with MG63 cells show that the CNT/Glass/HA composites guarantee the adhesion and proliferation of bone cells, and stimulate their phenotype expression, namely the alkaline phosphate (ALP). The interactions between the composite materials and the culture medium (α-MEM), under an applied electrical external field, were studied by scanning vibrating electrode technique. An increase of the culture medium electrical conductivity and the electrical field confinement in the presence of the conductive samples submerged in the medium was demonstrated. The in vitro electrical stimulation of MG63 cells on the conductive composites promotes the increase of the cell metabolic activity and DNA content by 130% and 60%, relatively to the non-stimulated condition, after only 3 days of daily stimulation of 15 μA for 15 min. Moreover, the osteoblastic gene expression for Runx2, osteocalcin (OC) and ALP was enhanced by 80%, 50% and 25%, after 5 days of stimulation. Instead, for dielectric materials, the stimulus delivering was less efficient, giving an equal or lower cellular response than the non-stimulated condition. The proposed electroconductive bone grafts offer exciting possibilities in bone regeneration strategies by delivering in situ electrical stimulus to cells and consequent control of the new bone tissue formation rate. It is expected that conductive smart biomaterials might turn the selective bone electrotherapy of clinical relevance by decreasing the postoperative healing times.
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Adenosine A1 receptors (A1Rs) play a critical role in osteoclast formation and function
Kara, Firas M.; Chitu, Violeta; Sloane, Jennifer; Axelrod, Matthew; Fredholm, Bertil B.; Stanley, E. Richard; Cronstein, Bruce N.
2010-01-01
Adenosine regulates a wide variety of physiological processes via interaction with one or more G-protein-coupled receptors (A1R, A2AR, A2BR, and A3R). Because A1R occupancy promotes fusion of human monocytes to form giant cells in vitro, we determined whether A1R occupancy similarly promotes osteoclast function and formation. Bone marrow cells (BMCs) were harvested from C57Bl/6 female mice or A1R-knockout mice and their wild-type (WT) littermates and differentiated into osteoclasts in the presence of colony stimulating factor-1 and receptor activator of NF-κB ligand in the presence or absence of the A1R antagonist 1,3-dipropyl-8-cyclopentyl xanthine (DPCPX). Osteoclast morphology was analyzed in tartrate-resistant acid phosphatase or F-actin-stained samples, and bone resorption was evaluated by toluidine blue staining of dentin. BMCs from A1R-knockout mice form fewer osteoclasts than BMCs from WT mice, and the A1R antagonist DPCPX inhibits osteoclast formation (IC50=1 nM), with altered morphology and reduced ability to resorb bone. A1R blockade increased ubiquitination and degradation of TRAF6 in RAW264.7 cells induced to differentiate into osteoclasts. These studies suggest a critical role for adenosine in bone homeostasis via interaction with adenosine A1R and further suggest that A1R may be a novel pharmacologic target to prevent the bone loss associated with inflammatory diseases and menopause.—Kara, F. M., Chitu, V., Sloane, J., Axelrod, M., Fredholm, B. B., Stanley, R., Cronstein, B. N. Adenosine A1 receptors (A1Rs) play a critical role in osteoclast formation and function. PMID:20181934
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Novel spinal instrumentation to enhance osteogenesis and fusion: a preliminary study.
MacEwan, Matthew R; Talcott, Michael R; Moran, Daniel W; Leuthardt, Eric C
2016-09-01
OBJECTIVE Instrumented spinal fusion continues to exhibit high failure rates in patients undergoing multilevel lumbar fusion or pseudarthrosis revision; with Grade II or higher spondylolisthesis; or in those possessing risk factors such as obesity, tobacco use, or metabolic disorders. Direct current (DC) electrical stimulation of bone growth represents a unique surgical adjunct in vertebral fusion procedures, yet existing spinal fusion stimulators are not optimized to enhance interbody fusion. To develop an advanced method of applying DC electrical stimulation to promote interbody fusion, a novel osteogenic spinal system capable of routing DC through rigid instrumentation and into the vertebral bodies was fabricated. A pilot study was designed to assess the feasibility of osteogenic instrumentation and compare the ability of osteogenic instrumentation to promote successful interbody fusion in vivo to standard spinal instrumentation with autograft. METHODS Instrumented, single-level, posterior lumbar interbody fusion (PLIF) with autologous graft was performed at L4-5 in adult Toggenburg/Alpine goats, using both osteogenic spinal instrumentation (plus electrical stimulation) and standard spinal instrumentation (no electrical stimulation). At terminal time points (3 months, 6 months), animals were killed and lumbar spines were explanted for radiographic analysis using a SOMATOM Dual Source Definition CT Scanner and high-resolution Microcat II CT Scanner. Trabecular continuity, radiodensity within the fusion mass, and regional bone formation were examined to determine successful spinal fusion. RESULTS Quantitative analysis of average bone density in pedicle screw beds confirmed that electroactive pedicle screws used in the osteogenic spinal system focally enhanced bone density in instrumented vertebral bodies. Qualitative and quantitative analysis of high-resolution CT scans of explanted lumbar spines further demonstrated that the osteogenic spinal system induced solid bony fusion across the L4-5 disc space as early as 6 weeks postoperatively. In comparison, inactive spinal instrumentation with autograft was unable to promote successful interbody fusion by 6 months postoperatively. CONCLUSIONS Results of this study demonstrate that novel osteogenic spinal instrumentation supports interbody fusion through the focal delivery of DC electrical stimulation. With further technical development and scientific/clinical validation, osteogenic spinal instrumentation may offer a unique alternative to biological scaffolds and pharmaceutical adjuncts used in spinal fusion procedures.
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Liu, Xing; Qin, Jiaqiang; Luo, Qing; Bi, Yang; Zhu, Gaohui; Jiang, Wei; Kim, Stephanie H; Li, Mi; Su, Yuxi; Nan, Guoxin; Cui, Jing; Zhang, Wenwen; Li, Ruidong; Chen, Xiang; Kong, Yuhan; Zhang, Jiye; Wang, Jinhua; Rogers, Mary Rose; Zhang, Hongyu; Shui, Wei; Zhao, Chen; Wang, Ning; Liang, Xi; Wu, Ningning; He, Yunfeng; Luu, Hue H; Haydon, Rex C; Shi, Lewis L; Li, Tingyu; He, Tong-Chuan; Li, Ming
2013-09-01
Mesenchymal stem cells (MSCs) are multipotent progenitors, which give rise to several lineages, including bone, cartilage and fat. Epidermal growth factor (EGF) stimulates cell growth, proliferation and differentiation. EGF acts by binding with high affinity to epidermal growth factor receptor (EGFR) on the cell surface and stimulating the intrinsic protein tyrosine kinase activity of its receptor, which initiates a signal transduction cascade causing a variety of biochemical changes within the cell and regulating cell proliferation and differentiation. We have identified BMP9 as one of the most osteogenic BMPs in MSCs. In this study, we investigate if EGF signalling cross-talks with BMP9 and regulates BMP9-induced osteogenic differentiation. We find that EGF potentiates BMP9-induced early and late osteogenic markers of MSCs in vitro, which can be effectively blunted by EGFR inhibitors Gefitinib and Erlotinib or receptor tyrosine kinase inhibitors AG-1478 and AG-494 in a dose- and time-dependent manner. Furthermore, EGF significantly augments BMP9-induced bone formation in the cultured mouse foetal limb explants. In vivo stem cell implantation experiment reveals that exogenous expression of EGF in MSCs can effectively potentiate BMP9-induced ectopic bone formation, yielding larger and more mature bone masses. Interestingly, we find that, while EGF can induce BMP9 expression in MSCs, EGFR expression is directly up-regulated by BMP9 through Smad1/5/8 signalling pathway. Thus, the cross-talk between EGF and BMP9 signalling pathways in MSCs may underline their important roles in regulating osteogenic differentiation. Harnessing the synergy between BMP9 and EGF should be beneficial for enhancing osteogenesis in regenerative medicine. © 2013 The Authors. Journal of Cellular and Molecular Medicine Published by Foundation for Cellular and Molecular Medicine/Blackwell Publishing Ltd.
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Liu, Xing; Qin, Jiaqiang; Luo, Qing; Bi, Yang; Zhu, Gaohui; Jiang, Wei; Kim, Stephanie H; Li, Mi; Su, Yuxi; Nan, Guoxin; Cui, Jing; Zhang, Wenwen; Li, Ruidong; Chen, Xiang; Kong, Yuhan; Zhang, Jiye; Wang, Jinhua; Rogers, Mary Rose; Zhang, Hongyu; Shui, Wei; Zhao, Chen; Wang, Ning; Liang, Xi; Wu, Ningning; He, Yunfeng; Luu, Hue H; Haydon, Rex C; Shi, Lewis L; Li, Tingyu; He, Tong-Chuan; Li, Ming
2013-01-01
Mesenchymal stem cells (MSCs) are multipotent progenitors, which give rise to several lineages, including bone, cartilage and fat. Epidermal growth factor (EGF) stimulates cell growth, proliferation and differentiation. EGF acts by binding with high affinity to epidermal growth factor receptor (EGFR) on the cell surface and stimulating the intrinsic protein tyrosine kinase activity of its receptor, which initiates a signal transduction cascade causing a variety of biochemical changes within the cell and regulating cell proliferation and differentiation. We have identified BMP9 as one of the most osteogenic BMPs in MSCs. In this study, we investigate if EGF signalling cross-talks with BMP9 and regulates BMP9-induced osteogenic differentiation. We find that EGF potentiates BMP9-induced early and late osteogenic markers of MSCs in vitro, which can be effectively blunted by EGFR inhibitors Gefitinib and Erlotinib or receptor tyrosine kinase inhibitors AG-1478 and AG-494 in a dose- and time-dependent manner. Furthermore, EGF significantly augments BMP9-induced bone formation in the cultured mouse foetal limb explants. In vivo stem cell implantation experiment reveals that exogenous expression of EGF in MSCs can effectively potentiate BMP9-induced ectopic bone formation, yielding larger and more mature bone masses. Interestingly, we find that, while EGF can induce BMP9 expression in MSCs, EGFR expression is directly up-regulated by BMP9 through Smad1/5/8 signalling pathway. Thus, the cross-talk between EGF and BMP9 signalling pathways in MSCs may underline their important roles in regulating osteogenic differentiation. Harnessing the synergy between BMP9 and EGF should be beneficial for enhancing osteogenesis in regenerative medicine. PMID:23844832
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Nagata, T.; Todescan, R.; Goldberg, H.A.
Secreted phosphoprotein I (SPPI) is a prominent structural protein in mineralized connective tissues. Rat bone cells in culture produce several forms of SPPI that differ in post-translational modifications such as phosphorylation and sulphation. To determine the significance of protein sulphation in bone formation, the synthesis of SPPI was studied in vitro using rat bone marrow cells (RBMC) which form bone-like tissue when grown in the presence of dexamethasone (Dex) and beta-glycerophosphate (beta-GP). In the presence of 10(-7) M Dex SPPI expression was stimulated 4-5-fold. Radiolabelling multilayered RBMCs for 48 h with (35S)-methionine, Na2(35SO4), or Na3(32PO4) revealed that two major phosphorylatedmore » forms of SPPI were secreted into the culture medium: a highly phosphorylated form migrating at 44 kDa on 15% SDS-PAGE and a less phosphorylated 55 kDa form. In the mineralized tissue formed in the presence of Dex and beta-GP, both forms of SPPI, in addition to proteoglycans and a 67 kDa protein, incorporated significant amounts of (35SO4). Sulphation of SPPI was not observed in the absence of mineral formation, indicating that the sulphation of SPPI is closely associated with mineralization and that it can be used as a sensitive and specific marker for the osteoblastic phenotype.« less
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Bone Regeneration in Rat Cranium Critical-Size Defects Induced by Cementum Protein 1 (CEMP1)
Serrano, Janeth; Romo, Enrique; Bermúdez, Mercedes; Narayanan, A. Sampath; Zeichner-David, Margarita; Santos, Leticia; Arzate, Higinio
2013-01-01
Gene therapy approaches to bone and periodontal tissue engineering are being widely explored. While localized delivery of osteogenic factors like BMPs is attractive for promotion of bone regeneration; method of delivery, dosage and side effects could limit this approach. A novel protein, Cementum Protein 1 (CEMP1), has recently been shown to promote regeneration of periodontal tissues. In order to address the possibility that CEMP1 can be used to regenerate other types of bone, experiments were designed to test the effect of hrCEMP1 in the repair/regeneration of a rat calvaria critical-size defect. Histological and microcomputed tomography (µCT) analyses of the calvaria defect sites treated with CEMP1 showed that after 16 weeks, hrCEMP1 is able to induce 97% regeneration of the defect. Furthermore, the density and characteristics of the new mineralized tissues were normal for bone. This study demonstrates that hrCEMP1 stimulates bone formation and regeneration and has therapeutic potential for the treatment of bone defects and regeneration of mineralized tissues. PMID:24265720
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Bisphenyl-Polymer/Carbon-Fiber-Reinforced Composite Compared to Titanium Alloy Bone Implant
Petersen, Richard C.
2014-01-01
Aerospace/aeronautical thermoset bisphenyl-polymer/carbon-fiber-reinforced composites are considered as new advanced materials to replace metal bone implants. In addition to well-recognized nonpolar chemistry with related bisphenol-polymer estrogenic factors, carbon-fiber-reinforced composites can offer densities and electrical conductivity/resistivity properties close to bone with strengths much higher than metals on a per-weight basis. In vivo bone-marrow tests with Sprague-Dawley rats revealed far-reaching significant osseoconductivity increases from bisphenyl-polymer/carbon-fiber composites when compared to state-of-the-art titanium-6-4 alloy controls. Midtibial percent bone area measured from the implant surface increased when comparing the titanium alloy to the polymer composite from 10.5% to 41.6% at 0.8 mm, P < 10−4, and 19.3% to 77.7% at 0.1 mm, P < 10−8. Carbon-fiber fragments planned to occur in the test designs, instead of producing an inflammation, stimulated bone formation and increased bone integration to the implant. In addition, low-thermal polymer processing allows incorporation of minerals and pharmaceuticals for future major tissue-engineering potential. PMID:25553057
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Bisphenyl-Polymer/Carbon-Fiber-Reinforced Composite Compared to Titanium Alloy Bone Implant.
Petersen, Richard C
2011-05-03
Aerospace/aeronautical thermoset bisphenyl-polymer/carbon-fiber-reinforced composites are considered as new advanced materials to replace metal bone implants. In addition to well-recognized nonpolar chemistry with related bisphenol-polymer estrogenic factors, carbon-fiber-reinforced composites can offer densities and electrical conductivity/resistivity properties close to bone with strengths much higher than metals on a per-weight basis. In vivo bone-marrow tests with Sprague-Dawley rats revealed far-reaching significant osseoconductivity increases from bisphenyl-polymer/carbon-fiber composites when compared to state-of-the-art titanium-6-4 alloy controls. Midtibial percent bone area measured from the implant surface increased when comparing the titanium alloy to the polymer composite from 10.5% to 41.6% at 0.8 mm, P < 10 -4 , and 19.3% to 77.7% at 0.1 mm, P < 10 -8 . Carbon-fiber fragments planned to occur in the test designs, instead of producing an inflammation, stimulated bone formation and increased bone integration to the implant. In addition, low-thermal polymer processing allows incorporation of minerals and pharmaceuticals for future major tissue-engineering potential.
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Jimi, Eijiro; Fukushima, Hidefumi
2016-02-01
The transcriptional factor nuclear factor κB(NF-κB)regulates the expression of a wide variety of genes that are involved in immune and inflammatory responses, proliferation, and tumorigenesis. NF-κB consists of five members, such as p65(RelA), RelB, c-Rel, p50/p105(NF-κB1), and p52/p100(NF-κB2). There are two distinct NF-κB activation pathways, termed the classical and alternative NF-κB signaling pathways. Since mice lacking both p50 and p52 subunits developed typical osteopetrosis, due to total lack of osteoclasts, NF-κB is also important osteoclast differentiation. A selective NF-κB inhibitor blocked receptor activator of NF-κB ligand(RANKL)-induced osteoclastogenesis both in vitro and in vivo. Recent findings have shown that inactivation of NF-κB enhances osteoblast differentiation in vitro and bone formation in vivo. NF-κB is constitutively activated in many cancers including oral squamous cell carcinoma(OSCC), and is involved in the invasive characteristics of OSCC. A selective NF-κB inhibitor also prevented jaw bone destruction by OSCC by reduced osteoclast numbers in animal model. Thus the inhibition of NF-κB might useful for the treatment of bone diseases, such as arthritis, osteoporosis, periodontitis, and bone invasion by OSCC by inhibiting bone resorption and by stimulating bone formation.
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The connection between cellular mechanoregulation and tissue patterns during bone healing.
Repp, Felix; Vetter, Andreas; Duda, Georg N; Weinkamer, Richard
2015-09-01
The formation of different tissues in the callus during secondary bone healing is at least partly influenced by mechanical stimuli. We use computer simulations to test the consequences of different hypotheses of the mechanoregulation at the cellular level on the patterns of tissues formed during healing. The computational study is based on an experiment on sheep, where after a tibial osteotomy, histological sections were harvested at different time points. In the simulations, we used a recently proposed basic phenomenological model, which allows ossification to occur either via endochondral or intramembranous ossification, but tries otherwise to employ a minimal number of simulation parameters. The model was extended to consider also the possibility of bone resorption and consequently allowing a description of the full healing progression till the restoration of the cortex. Specifically, we investigated how three changes in the mechanoregulation influence the resulting tissue patterns: (1) a time delay between stimulation of the cell and the formation of the tissue, (2) a variable mechanosensitivity of the cells, and (3) an independence of long time intervals of the soft tissue maturation from the mechanical stimulus. For all three scenarios, our simulations do not show qualitative differences in the time development of the tissue patterns. Largest differences were observed in the intermediate phases of healing in the amount and location of the cartilage. Interestingly, the course of healing was virtually unaltered in case of scenario (3) where tissue maturation proceeded independent of mechanical stimulation.
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Bachagol, Deepa; Joseph, Gilbert Stanley; Ellur, Govindraj; Patel, Kalpana; Aruna, Pamisetty; Mittal, Monika; China, Shyamsundar Pal; Singh, Ravendra Pratap; Sharan, Kunal
2018-02-01
Peak bone mass (PBM) achieved at adulthood is a strong determinant of future onset of osteoporosis, and maximizing it is one of the strategies to combat the disease. Recently, pomegranate seed oil (PSO) has been shown to have bone-sparing effect in ovariectomized mice. However, its effect on growing skeleton and its molecular mechanism remain unclear. In the present study, we evaluated the effect of PSO on PBM in growing rats and associated mechanism of action. PSO was given at various doses to 21-day-old growing rats for 90 days by oral gavage. The changes in bone parameters were assessed by micro-computed tomography and histology. Enzyme-linked immunosorbent assay was performed to analyze the levels of serum insulin-like growth factor type 1 (IGF-1). Western blotting from bone and liver tissues was done. Chromatin immunoprecipitation assay was performed to study the histone acetylation levels at IGF-1 gene. The results of the study show that PSO treatment significantly increases bone length, bone formation rate, biomechanical parameters, bone mineral density and bone microarchitecture along with enhancing muscle and brown fat mass. This effect was due to the increased serum levels of IGF-1 and stimulation of its signaling in the bones. Studies focusing on acetylation of histones in the liver, the major site of IGF-1 synthesis, showed enrichment of acetylated H3K9 and H3K14 at IGF-1 gene promoter and body. Further, the increased acetylation at H3K9 and H3K14 was associated with a reduced HDAC1 protein level. Together, our data suggest that PSO promotes the PBM achievement via increased IGF-1 expression in liver and IGF-1 signaling in bone. Copyright © 2017 Elsevier Inc. All rights reserved.
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Role of sclerostin in bone and cartilage and its potential as a therapeutic target in bone diseases
2014-01-01
Sclerostin is a small protein expressed by the SOST gene in osteocytes, bone cells that respond to mechanical stress applied to the skeleton and appear to play an important role in the regulation of bone remodeling. When sclerostin binds to its receptors on the cell surface of osteoblasts, a downstream cascade of intracellular signaling is initiated, with the ultimate effect of inhibiting osteoblastic bone formation. Recent studies have shown that the SOST gene is also expressed by articular chondrocytes and that modulation of its activity may have effects on articular cartilage and subchondral bone. The role of sclerostin in the pathogenesis of osteoarthritis in humans has not yet been defined, and the potential utility of treating osteoarthritis with interventions that alter sclerostin is not known. Rare genetic skeletal disorders in humans with low sclerostin levels, such as sclerosteosis and van Buchem disease, have been associated with a high bone mineral density (BMD) phenotype and low risk of fractures. This has led to the concept that antisclerostin interventions might be useful in the treatment of patients with osteoporosis and skeletal disorders associated with low bone mass. Compounds that inhibit sclerostin have been shown to stimulate bone formation and reduce bone resorption, with a robust increase in BMD. Investigational monoclonal antibodies to sclerostin, including romosozumab, blosozumab, and BPS804, have advanced to phase II clinical trials or beyond. If antisclerostin therapy is found to have beneficial effects on clinical endpoints, such as reduction of fracture risk or improvement in quality of life in patients with osteoarthritis, with a favorable balance of benefit and risk, then this class of compounds may become a prominent addition to the options for therapy of osteoporosis and other skeletal disorders. PMID:24688605
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Knee loading inhibits osteoclast lineage in a mouse model of osteoarthritis
Li, Xinle; Yang, Jing; Liu, Daquan; Li, Jie; Niu, Kaijun; Feng, Shiqing; Yokota, Hiroki; Zhang, Ping
2016-01-01
Osteoarthritis (OA) is a whole joint disorder that involves cartilage degradation and periarticular bone response. Changes of cartilage and subchondral bone are associated with development and activity of osteoclasts from subchondral bone. Knee loading promotes bone formation, but its effects on OA have not been well investigated. Here, we hypothesized that knee loading regulates subchondral bone remodeling by suppressing osteoclast development, and prevents degradation of cartilage through crosstalk of bone-cartilage in osteoarthritic mice. Surgery-induced mouse model of OA was used. Two weeks application of daily dynamic knee loading significantly reduced OARSI scores and CC/TAC (calcified cartilage to total articular cartilage), but increased SBP (subchondral bone plate) and B.Ar/T.Ar (trabecular bone area to total tissue area). Bone resorption of osteoclasts from subchondral bone and the differentiation of osteoclasts from bone marrow-derived cells were completely suppressed by knee loading. The osteoclast activity was positively correlated with OARSI scores and negatively correlated with SBP and B.Ar/T.Ar. Furthermore, knee loading exerted protective effects by suppressing osteoclastogenesis through Wnt signaling. Overall, osteoclast lineage is the hyper responsiveness of knee loading in osteoarthritic mice. Mechanical stimulation prevents OA-induced cartilage degeneration through crosstalk with subchondral bone. Knee loading might be a new potential therapy for osteoarthritis patients. PMID:27087498
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Wang, Weidan; Wan, Peng; Liu, Chen; Tan, Lili; Li, Weirong; Li, Lugee; Yang, Ke
2015-01-01
Poor corrosion resistance is one of the main disadvantages for biodegradable magnesium-based metals, especially applied for bone fixation, where there is a high demand of bio-mechanical strength and stability. Surface coating has been proved as an effective method to control the in vivo degradation. In this study a Ca-P self-sealing micro-arc oxidation (MAO) coating was studied to verify its efficacy and biological properties by in vitro and in vivo tests. It was found that the MAO coating could effectively retard the degradation according to immersion and electrochemical tests as well as 3D reconstruction by X-ray tomography after implantation. The MAO coating exhibited no toxicity and could stimulate the new bone formation. Therefore, the Ca-P self-sealing MAO coating could be a potential candidate for application of biodegradable Mg-based implant in bone fixations. PMID:26816635
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A New Regulator of Osteoclastogenesis: Estrogen Response Element–Binding Protein in Bone
Chen, Hong; Gilbert, Linda C; Lu, X; Liu, Zhaofan; You, Shaojin; Weitzmann, M Neale; Nanes, Mark S; Adams, John
2012-01-01
The heterogeneous nuclear ribonucleoprotein (hnRNP)–like estrogen response element–binding protein (ERE-BP) competes with estrogen receptor α (ERα) for occupancy of estrogen response elements (EREs). Here we report that ERE-BP potently stimulates osteoclastogenesis. ERE-BP mRNA and protein were found to be expressed ubiquitously in bone. Overexpression of ERE-BP in cultured osteoblasts stimulated expression of the receptor activator of NF-κB ligand (RANKL) and decreased osteoprotegerin (OPG). The effect of ERE-BP on RANKL was shown to be transcriptional in transient transfection assay and competed with via the ER. Constitutive expression of ERE-BP increased the sensitivity of cells toward 1,25-dihydroxyvitamin D3 stimulation of RANKL expression. In contrast, knockdown of ERE-BP in stromal ST-2 cells decreased basal RANKL promoter activity. Cocultures of ERE-BP lentivirus–transduced ST-2 cells with spleen monocytes induced formation of multinucleated osteoclasts (OCs) characterized by tartrate-resistant acid phosphatase, calcitonin receptors, and functional calcium resorption from bone slices. Although ERα competed with ERE-BP for an ERE in a dose-dependent manner, ERE-BP was an independent and potent regulator of RANKL and osteoclastogenesis. In preosteoclastic RAW cells, overexpression of ERE-BP increased RANK, upregulated NF-κB signaling, and enhanced differentiation toward a mature OC phenotype independent of RANKL. These results identify ERE-BP as a potent modulator of osteoclastogenesis. We hypothesize that ERE-BP may play a critical role in the regulation of bone homeostasis as a modulator of estrogen sensitivity as well as by direct action on the transcription of critical osteoclastogenic genes. PMID:21773989
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NASA Technical Reports Server (NTRS)
Yamaguchi, T.; Chattopadhyay, N.; Kifor, O.; Butters, R. R. Jr; Sugimoto, T.; Brown, E. M.; O'Malley, B. W. (Principal Investigator)
1998-01-01
The calcium-sensing receptor (CaR) is a G protein-coupled receptor that plays key roles in extracellular calcium ion (Ca2+o) homeostasis in parathyroid gland and kidney. Osteoblasts appear at sites of osteoclastic bone resorption during bone remodeling in the "reversal" phase following osteoclastic resorption and preceding bone formation. Bone resorption produces substantial local increases in Ca2+o that could provide a signal for osteoblasts in the vicinity, leading us to determine whether such osteoblasts express the CaR. In this study, we used the mouse osteoblastic, clonal cell line MC3T3-E1. Both immunocytochemistry and Western blot analysis, using an antiserum specific for the CaR, detected CaR protein in MC3T3-E1 cells. We also identified CaR transcripts in MC3T3-E1 cells by Northern analysis using a CaR-specific riboprobe and by reverse transcription-polymerase chain reaction with CaR-specific primers, followed by nucleotide sequencing of the amplified products. Exposure of MC3T3-E1 cells to high Ca2+o (up to 4.8 mM) or the polycationic CaR agonists, neomycin and gadolinium (Gd3+), stimulated both chemotaxis and DNA synthesis in MC3T3-E1 cells. Therefore, taken together, our data strongly suggest that the osteoblastic cell line MC3T3-E1 possesses both CaR protein and mRNA very similar, if not identical, to those in parathyroid and kidney. Furthermore, the CaR in these osteoblasts could play a key role in regulating bone turnover by stimulating the proliferation and migration of such cells to sites of bone resorption as a result of local release of Ca2+o.
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Vrahnas, Christina; Pearson, Thomas A; Brunt, Athena R; Forwood, Mark R; Bambery, Keith R; Tobin, Mark J; Martin, T John; Sims, Natalie A
2016-12-01
Intermittent administration of parathyroid hormone (PTH) is used to stimulate bone formation in patients with osteoporosis. A reduction in the degree of matrix mineralisation has been reported during treatment, which may reflect either production of undermineralised matrix or a greater proportion of new matrix within the bone samples assessed. To explore these alternatives, high resolution synchrotron-based Fourier Transform Infrared Microspectroscopy (sFTIRM) coupled with calcein labelling was used in a region of non-remodelling cortical bone to determine bone composition during anabolic PTH treatment compared with region-matched samples from controls. 8week old male C57BL/6 mice were treated with vehicle or 50μg/kg PTH, 5 times/week for 4weeks (n=7-9/group). Histomorphometry confirmed greater trabecular and periosteal bone formation and 3-point bending tests confirmed greater femoral strength in PTH-treated mice. Dual calcein labels were used to match bone regions by time-since-mineralisation (bone age) and composition was measured by sFTIRM in six 15μm 2 regions at increasing depth perpendicular to the most immature bone on the medial periosteal edge; this allowed in situ measurement of progressive changes in bone matrix during its maturation. The sFTIRM method was validated in vehicle-treated bones where the expected progressive increases in mineral:matrix ratio and collagen crosslink type ratio were detected with increasing bone maturity. We also observed a gradual increase in carbonate content that strongly correlated with an increase in longitudinal stretch of the collagen triple helix (amide I:amide II ratio). PTH treatment did not alter the progressive changes in any of these parameters from the periosteal edge through to the more mature bone. These data provide new information about how the bone matrix matures in situ and confirm that bone deposited during PTH treatment undergoes normal collagen maturation and normal mineral accrual. Copyright © 2016 Elsevier Inc. All rights reserved.
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Mechanical Signaling for Bone Modeling and Remodeling
Robling, Alexander G.; Turner, Charles H.
2012-01-01
Proper development of the skeleton in utero and during growth requires mechanical stimulation. Loading results in adaptive changes in bone that strengthen bone structure. Bone’s adaptive response is regulated by the ability of resident bone cells to perceive and translate mechanical energy into a cascade of structural and biochemical changes within the cells — a process known as mechanotransduction. Mechanotransduction pathways are among the most anabolic in bone, and consequently, there is great interest in elucidating how mechanical loading produces its observed effects, including increased bone formation, reduced bone loss, changes in bone cell differentiation and lifespan, among others. A molecular understanding of these processes is developing, and with it comes a profound new insight into the biology of bone. In this article, we review the nature of the physical stimulus to which bone cells mount an adaptive response, including the identity of the sensor cells, their attributes and physical environment, and putative mechanoreceptors they express. Particular attention is allotted to the focal adhesion and Wnt signaling, in light of their emerging role in bone mechanotransduction. The cellular mechanisms for increased bone loss during disuse, and reduced bone loss during loading are considered. Finally, we summarize the published data on bone cell accommodation, whereby bone cells stop responding to mechanical signaling events. Collectively, these data highlight the complex yet finely orchestrated process of mechanically regulated bone homeostasis. PMID:19817708
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Possible therapeutic potential of berberine in diabetic osteopathy.
Rahigude, A B; Kaulaskar, S V; Bhutada, P S
2012-10-01
Diabetic osteopathy is a complication that leads to decreased bone mineral density, bone formation and having high risk of fractures that heals slowly. Diabetic osteopathy is a result of increase in osteoclastogenesis and decrease in osteoblastogenesis. Various factors viz., oxidative stress, increased inflammatory markers, PPAR-γ activation in osteoblast, activation of apoptotic pathway, increased glucose levels and inhibitory effect on parathyroid hormone etc. are mainly responsible for decreased bone mineral density. Berberine is an isoquinoline alkaloid widely used in Asian countries as a traditional medicine. Berberine is extensively reported to be an antioxidant, anti-inflammatory, antidiabetic, and having potential to treat diabetic complications and glucocorticoid induced osteoporosis. The osteoclastogenesis decreasing property of berberine can be hypothesized for inhibiting diabetic osteopathy. In addition, chronic treatment of berberine will be helpful for increasing the osteoblastic activity and expression of the modulators that affect osteoblastic differentiation. The apoptotic pathways stimulated due to increased inflammatory markers and nucleic acid damages could be reduced due to berberine. Another important consideration that berberine is having stimulatory effect on glucagon like peptide release and insulin sensitization that will be helpful for decreasing glucose levels and therefore, may exerts osteogenesis. Thiazolidinediones show bone loss due to activation of PPAR-γ in osteoblasts, whereas berberine stimulates PPAR-γ only in adipocytes and not in osteoblasts, and therefore the decreased bone loss due to use of thiazolidinediones may not be observed in berberine treatment conditions. Berberine decreases the advanced glycation end-products (AGE) formation in diabetic condition which will be ultimately helpful to decrease the stiffness of collagen fibers due to AGE-induced cross linking. Lastly, it is also reported that berberine has inhibitory effect on parathyroid hormone and enhances marker genes like osteocalcin, which are responsible for the osteoblastic activity. From these evidences, we hypothesized that berberine may have potential in the treatment of diabetic osteopathy. Copyright © 2012 Elsevier Ltd. All rights reserved.
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Cho, Sun Wook; Bae, Jae Hyun; Noh, Gyeong Woon; Kim, Ye An; Moon, Min Kyong; Park, Kyoung Un; Song, Junghan; Yi, Ka Hee; Park, Do Joon; Chung, June-Key; Cho, Bo Youn; Park, Young Joo
2015-01-01
Osteoporosis-related fractures are one of the complications of Graves' disease. This study hypothesized that the different actions of thyroid-stimulating hormone receptor (TSHR) antibodies, both stimulating and blocking activities in Graves' disease patients might oppositely impact bone turnover. Newly diagnosed premenopausal Graves' disease patients were enrolled (n = 93) and divided into two groups: patients with TSHR antibodies with thyroid-stimulating activity (stimulating activity group, n = 83) and patients with TSHR antibodies with thyroid-stimulating activity combined with blocking activity (blocking activity group, n = 10). From the stimulating activity group, patients who had matched values for free T4 and TSH binding inhibitor immunoglobulin (TBII) to the blocking activity group were further classified as stimulating activity-matched control (n = 11). Bone turnover markers BS-ALP, Osteocalcin, and C-telopeptide were significantly lower in the blocking activity group than in the stimulating activity or stimulating activity-matched control groups. The TBII level showed positive correlations with BS-ALP and osteocalcin levels in the stimulating activity group, while it had a negative correlation with the osteocalcin level in the blocking activity group. In conclusion, the activation of TSHR antibody-activated TSH signaling contributes to high bone turnover, independent of the actions of thyroid hormone, and thyroid-stimulation blocking antibody has protective effects against bone metabolism in Graves' disease.
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Boos, Anja M; Loew, Johanna S; Deschler, Gloria; Arkudas, Andreas; Bleiziffer, Oliver; Gulle, Heinz; Dragu, Adrian; Kneser, Ulrich; Horch, Raymund E; Beier, Justus P
2011-06-01
Bone tissue engineering approaches increasingly focus on the use of mesenchymal stem cells (MSC). In most animal transplantation models MSC are isolated and expanded before auto cell transplantation which might be critical for clinical application in the future. Hence this study compares the potential of directly auto-transplanted versus in vitro expanded MSC with or without bone morphogenetic protein-2 (BMP-2) to induce bone formation in a large volume ceramic bone substitute in the sheep model. MSC were isolated from bone marrow aspirates and directly auto-transplanted or expanded in vitro and characterized using fluorescence activated cell sorting (FACS) and RT-PCR analysis before subcutaneous implantation in combination with BMP-2 and β-tricalcium phosphate/hydroxyapatite (β-TCP/HA) granules. Constructs were explanted after 1 to 12 weeks followed by histological and RT-PCR evaluation. Sheep MSC were CD29(+), CD44(+) and CD166(+) after selection by Ficoll gradient centrifugation, while directly auto-transplanted MSC-populations expressed CD29 and CD166 at lower levels. Both, directly auto-transplanted and expanded MSC, were constantly proliferating and had a decreasing apoptosis over time in vivo. Directly auto-transplanted MSC led to de novo bone formation in a heterotopic sheep model using a β-TCP/HA matrix comparable to the application of 60 μg/ml BMP-2 only or implantation of expanded MSC. Bone matrix proteins were up-regulated in constructs following direct auto-transplantation and in expanded MSC as well as in BMP-2 constructs. Up-regulation was detected using immunohistology methods and RT-PCR. Dense vascularization was demonstrated by CD31 immunohistology staining in all three groups. Ectopic bone could be generated using directly auto-transplanted or expanded MSC with β-TCP/HA granules alone. Hence BMP-2 stimulation might become dispensable in the future, thus providing an attractive, clinically feasible approach to bone tissue engineering. © 2011 The Authors Journal of Cellular and Molecular Medicine © 2011 Foundation for Cellular and Molecular Medicine/Blackwell Publishing Ltd.
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Ma, Xiaoqing; Xu, Zhongyang; Ding, Shaofeng; Yi, Guangkun; Wang, Qian
2018-01-01
Alendronate is commonly used for the treatment of postmenopausal osteoporosis; however, the underlying pathological molecular mechanisms of its action remain unclear. In the present study, the alendronate-treated signaling pathway in bone metabolism in rats with ovariectomy induced by osteoporosis was investigated. Rats with osteoporosis were orally administered alendronate or phosphate-buffered saline (control). In addition, the interferon-β (IFN-β)/signal transducer and activator of transcription 1 (STAT1) signaling pathway was investigated in osteoblasts following treatment with alendronate in vitro and in vivo. During the differentiation period, IFN-β (100 ng/ml) was used to treat the osteoblast cells, and the activity, viability and bone metabolism-associated gene expression levels (STAT1, p-STAT1, Fra1, TRAF6 and SOCS1) were analyzed in osteoblast cells. Histopathological changes were used to evaluate osteoblasts, osteoclasts, inflammatory phase of bone healing and osteonecrotic areas. The results demonstrated that alendronate significantly inhibited the activity of osteoporotic osteoclasts by stimulating expression of IFN-β, as well as markedly improved the viability and activity of osteoblasts compared with the control group. In addition, alendronate increased the expression and phosphorylation levels of STAT1 in osteoclasts, enhanced osteoblast differentiation, upregulated the expression levels of alkaline phosphatase and osteocalcin, and increased the expression of osteoblast differentiation-associated genes (osteocalcin, osterix and Runx2). Inhibition of IFN-β expression canceled the benefits of alendronate-mediated osteoblast differentiation. Notably, alendronate enhanced bone formation in rats with osteoporosis induced by ovariectomy. In conclusion, these findings suggest that alendronate can regulate osteoblast differentiation and bone formation in rats with osteoporosis induced by ovariectomy through upregulation of IFN-β/STAT1 signaling pathway. PMID:29375681
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Mejía, Wilson; Córdoba, Diana; Durán, Paola; Chacón, Yersson; Rosselli, Diego
2018-01-16
A soy protein-based supplement may optimize bone health, support physical growth, and stimulate bone formation. This study aimed to assess the effect of a daily soy protein supplement (SPS) on nutritional status, bone formation markers, lipid profile, and daily energy and macronutrient intake in children. One hundred seven participants (62 girls), ages 2 to 9, started the study and were randomly assigned to lunch fruit juice with (n = 57, intervention group) or without (n = 50, control group) addition of 45 g (230 Kcal) of a commercial SPS during 12 months; 84 children (51 girls, 33 boys) completed the study (45 and 39 intervention and control, respectively). Nutritional assessment included anthropometry and nutrient intakes; initial and final blood samples were taken; insulin-like growth factor-I (IGF-I), osteocalcin, bone specific alkaline phosphatase (BAP), insulin-like growth factor binding protein-3 (IGFBP-3), cholesterol, triglycerides, low-density lipoprotein (LDL), and high-density lipoprotein (HDL) were analyzed. Statistically significant changes (p < .05) in body mass index and weight for age Z scores were observed between groups while changes in body composition were not. Changes in energy, total protein, and carbohydrate intakes were significantly higher in the intervention group (p < .01). Calorie intake changes were statistically significant between groups (p < .001), and BAP decreased in both groups, with values within normal ranges. Osteocalcin, IGFBP-3, and lipid profile were not different between groups. IGF-I levels and IGF/IGFBP-3 ratio increased significantly in both groups. In conclusion, changes in macronutrient and energy intake and nutritional status in the intervention group compared to control group may ensure harmonious and adequate bone health and development.
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Role of HIF-1α in skeletal development
Wan, Chao; Shao, Jin; Gilbert, Shawn R.; Riddle, Ryan C.; Long, Fanxin; Johnson, Randall S.; Schipani, Ernestina; Clemens, Thomas L.
2011-01-01
Angiogenesis and osteogenesis are tightly coupled during bone development and regeneration. Mesenchymal cells in the developing stroma elicit angiogenic signals to recruit new blood vessels into bone. Reciprocal signals, likely emanating from the incoming vascular endothelium, stimulate mesenchymal cell specification through additional interactions with cells within the vascular stem cell niche. The hypoxia-inducible factor-1 alpha (HIF-1) pathway has been identified as a key component in this process. We demonstrated that overexpression of HIF-1 in mature osteoblasts through disruption of the von Hippel-Lindau protein profoundly increases angiogenesis and osteogenesis; these processes appear to be coupled by cell nonautonomous mechanisms involving the action of vascular endothelial growth factor (VEGF) on the endothelial cells. The same occurred in the model of injury-mediated bone regeneration (distraction osteogenesis). Surprisingly, manipulation of HIF-1 does not influence angiogenesis of the skull bones, where earlier activation of HIF-1 in the condensing mesenchyme upregulates osterix during cranial bone formation. PMID:20392254
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An emerging cell-based strategy in orthopaedics: endothelial progenitor cells.
Atesok, Kivanc; Matsumoto, Tomoyuki; Karlsson, Jon; Asahara, Takayuki; Atala, Anthony; Doral, M Nedim; Verdonk, Rene; Li, Ru; Schemitsch, Emil
2012-07-01
The purpose of this article was to analyze the results of studies in the literature, which evaluated the use of endothelial progenitor cells (EPCs) as a cell-based tissue engineering strategy. EPCs have been successfully used in regenerative medicine to augment neovascularization in patients after myocardial infarction and limb ischemia. EPCs' important role as vasculogenic progenitors presents them as a potential source for cell-based therapies to promote bone healing. EPCs have been shown to have prominent effects in promoting bone regeneration in several animal models. Evidence indicates that EPCs promote bone regeneration by stimulating both angiogenesis and osteogenesis through a differentiation process toward endothelial cell lineage and formation of osteoblasts. Moreover, EPCs increase vascularization and osteogenesis by increased secretion of growth factors and cytokines through paracrine mechanisms. EPCs offer the potential to emerge as a new strategy among other cell-based therapies to promote bone regeneration. Further investigations and human trials are required to address current questions with regard to biology and mechanisms of action of EPCs in bone tissue engineering.
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Boeree, N R; Dove, J; Cooper, J J; Knowles, J; Hastings, G W
1993-08-01
This study evaluates the mechanical properties of a composite material comprising polyhydroxybutyrate with hydroxyapatite added in proportions varying from 0 to 50%. Among the three methods of production, injection moulding was found to result in the most satisfactory mechanical properties. The tensile and compressive strength and the modulus of elasticity of composite produced in this way fell within the range for fresh human bone from different anatomical sites. With the additional advantages of biocompatibility, biodegradability and the potential for piezoelectric stimulation of new local bone formation, it was concluded that the injection-moulded composite material has considerable potential for use in orthopaedic surgery, both as a material to construct certain orthopaedic implants and as an alternative to corticocancellous bone graft.
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Fawzy El-Sayed, Karim M; Dörfer, Christof; Ungefroren, Hendrick; Kassem, Neemat; Wiltfang, Jörg; Paris, Sebastian
2014-07-01
The objective of this study was to evaluate the effect of Emdogain (Enamel Matrix Derivative, EMD) and Bone Morphogenetic Protein-2 (BMP-2), either solely or in combination, on the gene expression and mineralized nodule formation of alveolar bone proper-derived stem/progenitor cells. Stem/progenitor cells were isolated from human alveolar bone proper, magnetically sorted using STRO-1 antibodies, characterized flowcytometrically for their surface markers' expression, and examined for colony formation and multilineage differentiation potential. Subsequently, cells were treated over three weeks with 100 μg/ml Emdogain (EMD-Group), or 100 ng/ml BMP-2 (BMP-Group), or a combination of 100 ng/ml BMP-2 and 100 μg/ml Emdogain (BMP/EMD-Group). Unstimulated stem/progenitor cells (MACS(+)-Group) and osteoblasts (OB-Group) served as controls. Osteogenic gene expression was analyzed using RTq-PCR after 1, 2 and 3 weeks (N = 3/group). Mineralized nodule formation was evaluated by Alizarin-Red staining. BMP and EMD up-regulated the osteogenic gene expression. The BMP Group showed significantly higher expression of Collagen-I, III, and V, Alkaline phosphatase and Osteonectin compared to MACS(+)- and OB-Group (p < 0.05; Two-way ANOVA/Bonferroni) with no mineralized nodule formation. Under in-vitro conditions, Emdogain and BMP-2 up-regulate the osteogenic gene expression of stem/progenitor cells. The combination of BMP-2 and Emdogain showed no additive effect and would not be recommended for a combined clinical stimulation. Copyright © 2013 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.
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Cook, Jeremy J; Summers, N Jake; Cook, Emily A
2015-01-01
Electromagnetic fields and their uses in bone healing have been fairly well studied, with most results showing improvement in healing of both bone and cartilage. Most supportive data are found in relation to the spine, femur, and tibia, but there is increasing evidence for its use in the foot and ankle for treatment of nonunions and as an adjunctive device in arthrodeses, particularly in high-risk populations. There are varying data and a significant variety of quality in the current research and publications concerning the use of electrical bone stimulation in the treatment of the foot and ankle. Thus, there is a definite need for further investigation and high-quality study designs to determine the most effective treatment modalities and pathologies best used with bone stimulation. Bone stimulation should be viewed as an adjunctive procedure in which the surgeon optimizes the high-risk patient both medically or surgically whenever possible. But when used appropriately, bone stimulation has the potential to influence outcomes and aid in bone healing when complications arise and in high-risk populations. Copyright © 2015 Elsevier Inc. All rights reserved.
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Thompson, Michelle L; Chartier, Stephane R; Mitchell, Stefanie A; Mantyh, Patrick W
2016-01-01
Age-related bone fractures are usually painful and have highly negative effects on a geriatric patient's functional status, quality of life, and survival. Currently, there are few analgesic therapies that fully control bone fracture pain in the elderly without significant unwanted side effects. However, another way of controlling age-related fracture pain would be to preemptively administer an osteo-anabolic agent to geriatric patients with high risk of fracture, so as to build new cortical bone and prevent the fracture from occurring. A major question, however, is whether an osteo-anabolic agent can stimulate the proliferation of osteogenic cells and build significant amounts of new cortical bone in light of the decreased number and responsiveness of osteogenic cells in aging bone. To explore this question, geriatric and young mice, 20 and 4 months old, respectively, received either vehicle or a monoclonal antibody that sequesters sclerostin (anti-sclerostin) for 28 days. From days 21 to 28, animals also received sustained administration of the thymidine analog, bromodeoxyuridine (BrdU), which labels the DNA of dividing cells. Animals were then euthanized at day 28 and the femurs were examined for cortical bone formation, bone mineral density, and newly borne BrdU+ cells in the periosteum which is a tissue that is pivotally involved in the formation of new cortical bone. In both the geriatric and young mice, anti-sclerostin induced a significant increase in the thickness of the cortical bone, bone mineral density, and the proliferation of newly borne BrdU+ cells in the periosteum. These results suggest that even in geriatric animals, anti-sclerostin therapy can build new cortical bone and increase the proliferation of osteogenic cells and thus reduce the likelihood of painful age-related bone fractures. © The Author(s) 2016.
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Ishack, Stephanie; Mediero, Aranzazu; Wilder, Tuere; Ricci, John L.; Cronstein, Bruce N.
2017-01-01
Bone defects resulting from trauma or infection need timely and effective treatments to restore damaged bone. Using specialized three-dimensional (3-D) printing technology we have created custom 3-D scaffolds of hydroxyapatite (HA)/Beta-Tri-Calcium Phosphate (β-TCP) to promote bone repair. To further enhance bone regeneration we have coated the scaffolds with dipyridamole, an agent that increases local adenosine levels by blocking cellular uptake of adenosine. 15% HA:85% β-TCP scaffolds were designed using Robocad software, fabricated using a 3-D Robocasting system, and sintered at 1100°C for 4h. Scaffolds were coated with BMP-2 (200ng/ml), Dypiridamole 100µM or saline and implanted in C57B6 and adenosine A2A receptor knockout (A2AKO) mice with 3mm cranial critical bone defects for 2-8 weeks. Dipyridamole release from scaffold was assayed spectrophotometrically. MicroCT and histological analysis were performed. micro-computed tomography (microCT) showed significant bone formation and remodeling in HA/β-TCP- dipyridamole and HA/β-TCP -BMP-2 scaffolds when compared to scaffolds immersed in vehicle at 2, 4 and 8 weeks (n=5 per group; p≤ 0.05, p≤ 0.05 and p≤ 0.01, respectively). Histological analysis showed increased bone formation and a trend toward increased remodeling in HA/β-TCP- dipyridamole and HA/β-TCP-BMP-2 scaffolds. coating scaffolds with dipyridamole did not enhance bone regeneration in A2AKO mice. In conclusion, scaffolds printed with HA/β-TCP promote bone regeneration in critical bone defects and coating these scaffolds with agents that stimulate A2A receptors and growth factors can further enhance bone regeneration. These coated scaffolds may be very useful for treating critical bone defects due to trauma, infection or other causes. PMID:26513656
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Compact biomedical pulsed signal generator for bone tissue stimulation
Kronberg, J.W.
1993-06-08
An apparatus for stimulating bone tissue for stimulating bone growth or treating osteoporosis by applying directly to the skin of the patient an alternating current electrical signal comprising wave forms known to simulate the piezoelectric constituents in bone. The apparatus may, by moving a switch, stimulate bone growth or treat osteoporosis, as desired. Based on low-power CMOS technology and enclosed in a moisture-resistant case shaped to fit comfortably, two astable multivibrators produce the desired waveforms. The amplitude, pulse width and pulse frequency, and the subpulse width and subpulse frequency of the waveforms are adjustable. The apparatus, preferably powered by a standard 9-volt battery, includes signal amplitude sensors and warning signals indicate an output is being produced and the battery needs to be replaced.
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Compact biomedical pulsed signal generator for bone tissue stimulation
Kronberg, James W.
1993-01-01
An apparatus for stimulating bone tissue for stimulating bone growth or treating osteoporosis by applying directly to the skin of the patient an alternating current electrical signal comprising wave forms known to simulate the piezoelectric constituents in bone. The apparatus may, by moving a switch, stimulate bone growth or treat osteoporosis, as desired. Based on low-power CMOS technology and enclosed in a moisture-resistant case shaped to fit comfortably, two astable multivibrators produce the desired waveforms. The amplitude, pulse width and pulse frequency, and the subpulse width and subpulse frequency of the waveforms are adjustable. The apparatus, preferably powered by a standard 9-volt battery, includes signal amplitude sensors and warning signals indicate an output is being produced and the battery needs to be replaced.
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Chordekar, Shai; Perez, Ronen; Adelman, Cahtia; Sohmer, Haim; Kishon-Rabin, Liat
2018-04-03
Hearing can be elicited in response to bone as well as soft-tissue stimulation. However, the underlying mechanism of soft-tissue stimulation is under debate. It has been hypothesized that if skull vibrations were the underlying mechanism of hearing in response to soft-tissue stimulation, then skull vibrations would be associated with hearing thresholds. However, if skull vibrations were not associated with hearing thresholds, an alternative mechanism is involved. In the present study, both skull vibrations and hearing thresholds were assessed in the same participants in response to bone (mastoid) and soft-tissue (neck) stimulation. The experimental group included five hearing-impaired adults in whom a bone-anchored hearing aid was implanted due to conductive or mixed hearing loss. Because the implant is exposed above the skin and has become an integral part of the temporal bone, vibration of the implant represented skull vibrations. To ensure that middle-ear pathologies of the experimental group did not affect overall results, hearing thresholds were also obtained in 10 participants with normal hearing in response to stimulation at the same sites. We found that the magnitude of the bone vibrations initiated by the stimulation at the two sites (neck and mastoid) detected by the laser Doppler vibrometer on the bone-anchored implant were linearly related to stimulus intensity. It was therefore possible to extrapolate the vibration magnitudes at low-intensity stimulation, where poor signal-to-noise ratio limited actual recordings. It was found that the vibration magnitude differences (between soft-tissue and bone stimulation) were not different than the hearing threshold differences at the tested frequencies. Results of the present study suggest that bone vibration magnitude differences can adequately explain hearing threshold differences and are likely to be responsible for the hearing sensation. Thus, the present results support the idea that bone and soft-tissue conduction could share the same underlying mechanism, namely the induction of bone vibrations. Studies with the present methodology should be continued in future work in order to obtain further insight into the underlying mechanism of activation of the hearing system. Copyright © 2018 Elsevier B.V. All rights reserved.
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NASA Astrophysics Data System (ADS)
Qi, Xin; Pei, Peng; Zhu, Min; Du, Xiaoyu; Xin, Chen; Zhao, Shichang; Li, Xiaolin; Zhu, Yufang
2017-02-01
In the clinic, bone defects resulting from infections, trauma, surgical resection and genetic malformations remain a significant challenge. In the field of bone tissue engineering, three-dimensional (3D) scaffolds are promising for the treatment of bone defects. In this study, calcium sulfate hydrate (CSH)/mesoporous bioactive glass (MBG) scaffolds were successfully fabricated using a 3D printing technique, which had a regular and uniform square macroporous structure, high porosity and excellent apatite mineralization ability. Human bone marrow-derived mesenchymal stem cells (hBMSCs) were cultured on scaffolds to evaluate hBMSC attachment, proliferation and osteogenesis-related gene expression. Critical-sized rat calvarial defects were applied to investigate the effect of CSH/MBG scaffolds on bone regeneration in vivo. The in vitro results showed that CSH/MBG scaffolds stimulated the adhesion, proliferation, alkaline phosphatase (ALP) activity and osteogenesis-related gene expression of hBMSCs. In vivo results showed that CSH/MBG scaffolds could significantly enhance new bone formation in calvarial defects compared to CSH scaffolds. Thus 3D printed CSH/MBG scaffolds would be promising candidates for promoting bone regeneration.
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Sympathetic control of bone mass regulated by osteopontin
Nagao, Masashi; Feinstein, Timothy N.; Ezura, Yoichi; Hayata, Tadayoshi; Notomi, Takuya; Saita, Yoshitomo; Hanyu, Ryo; Hemmi, Hiroaki; Izu, Yayoi; Takeda, Shu; Wang, Kathryn; Rittling, Susan; Nakamoto, Tetsuya; Kaneko, Kazuo; Kurosawa, Hisashi; Karsenty, Gerard; Denhardt, David T.; Vilardaga, Jean-Pierre; Noda, Masaki
2011-01-01
The sympathetic nervous system suppresses bone mass by mechanisms that remain incompletely elucidated. Using cell-based and murine genetics approaches, we show that this activity of the sympathetic nervous system requires osteopontin (OPN), a cytokine and one of the major members of the noncollagenous extracellular matrix proteins of bone. In this work, we found that the stimulation of the sympathetic tone by isoproterenol increased the level of OPN expression in the plasma and bone and that mice lacking OPN (OPN-KO) suppressed the isoproterenol-induced bone loss by preventing reduced osteoblastic and enhanced osteoclastic activities. In addition, we found that OPN is necessary for changes in the expression of genes related to bone resorption and bone formation that are induced by activation of the sympathetic tone. At the cellular level, we showed that intracellular OPN modulated the capacity of the β2-adrenergic receptor to generate cAMP with a corresponding modulation of cAMP-response element binding (CREB) phosphorylation and associated transcriptional events inside the cell. Our results indicate that OPN plays a critical role in sympathetic tone regulation of bone mass and that this OPN regulation is taking place through modulation of the β2-adrenergic receptor/cAMP signaling system. PMID:21990347
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Union rate of tibiotalocalcaneal nails with internal or external bone stimulation.
De Vries, J George; Berlet, Gregory C; Hyer, Christopher F
2012-11-01
The use of bone growth stimulation has been reported in the application of hindfoot and ankle arthrodesis. Most studies have been retrospective case series with few patients. The authors present a comparative analysis of patients undergoing tibiotalocalcaneal (TTC) arthrodesis via a retrograde intramedullary arthrodesis nail to evaluate the influence of internal versus external bone stimulation in this population. One hundred fifty-four patients were treated with retrograde intramedullary nailing. A comprehensive chart and radiographic review was performed from a database of patients who underwent TTC fusion with or without bone stimulation. Ninety-one patients with retrograde TTC nailing were treated with direct current internal bone stimulation at the time of the index procedure (internal group) and 63 were treated with combined magnetic field external bone stimulation (external group). The primary end point was fusion with potential variables evaluated for influence on fusion rates. Demographically the cohorts were similar groups in age and comorbidities. Surgical and outcome data were examined, and there were few statistically significant differences between the two groups. There was no statistically significant difference in rate of union (52.7% and 57.1%, p = .63) or rate of complications between the internal and external groups. Overall, the success rate for achieving a stable, functional limb for the groups was 81.3% (74/91 patients) and 82.5% (52/63 patients) in the internal and external groups, respectively (p = .62). The authors demonstrated there were no statistically significant differences between the union and complication rate when comparing these types of internal and external bone stimulation in this patient population. Consideration of these results may help guide physicians when considering bone stimulation as an adjunct to TTC fusions with a retrograde intramedullary nail.
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Ramoglu, Sabri Ilhan; Sonmez, Mehmet Fatih
2016-01-01
Summary Background/objective: The aim of this study was to investigate the effects of different concentrations of ozone (O3) therapy on bone regeneration in response to an expansion of the inter-premaxillary suture in rats. Materials and methods: Forty-eight Wistar rats were randomly divided into four groups (n = 12). In groups I, II, and III, 1ml of O3 at 10, 25, and 40 µg/ml was injected at the premaxillary suture, respectively. In group IV (control group), 1ml of saline solution was injected at the same point during the expansion procedure for 5 days. Bone regeneration in the suture was evaluated histomorphometrically. The area of new bone and fibrotic area, the number of osteoblasts and osteoclasts, and the amount of vascularity were measured and compared. The density of the newly formed bone in the expansion area was measured by using cone beam computed tomography. Data were analyzed using the Kruskal–Wallis one-way analysis of variance and post hoc Student-Newman–Keuls tests. Results: New bone area, fibrotic area, osteoblast and osteoclast numbers, and the amount of vascularity were significantly higher in experimental groups compared with the control group (P < 0.001). The density of newly formed bone (P < 0.001), new bone formation (P = 0.009), number of capillaries (P < 0.001), number of osteoclasts (P = 0.016), and number of osteoblasts (P < 0.001) in the maxillary sutures were highest in the 25 μg/ml O3 group compared with the other experimental groups and control group. Conclusions/implications: The application of O3 therapy can stimulate bone regeneration in an orthopedically expanded inter-premaxillary suture during both the expansion and retention periods. PMID:26136437
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IGF-1 signaling mediated cell-specific skeletal mechano-transduction.
Tian, Faming; Wang, Yongmei; Bikle, Daniel D
2018-02-01
Mechanical loading preserves bone mass and stimulates bone formation, whereas skeletal unloading leads to bone loss. In addition to osteocytes, which are considered the primary sensor of mechanical load, osteoblasts, and bone specific mesenchymal stem cells also are involved. The skeletal response to mechanical signals is a complex process regulated by multiple signaling pathways including that of insulin-like growth factor-1 (IGF-1). Conditional osteocyte deletion of IGF-1 ablates the osteogenic response to mechanical loading. Similarly, osteocyte IGF-1 receptor (IGF-1R) expression is necessary for reloading-induced periosteal bone formation. Transgenic overexpression of IGF-1 in osteoblasts results in enhanced responsiveness to in vivo mechanical loading in mice, a response which is eliminated by osteoblastic conditional disruption of IGF-1 in vivo. Bone marrow derived stem cells (BMSC) from unloaded bone fail to respond to IGF-1 in vitro. IGF-1R is required for the transduction of a mechanical stimulus to downstream effectors, transduction which is lost when the IGF-1R is deleted. Although the molecular mechanisms are not yet fully elucidated, the IGF signaling pathway and its interactions with potentially interlinked signaling cascades involving integrins, the estrogen receptor, and wnt/β-catenin play an important role in regulating adaptive response of cancer bone cells to mechanical stimuli. In this review, we discuss recent advances investigating how IGF-1 and other interlinked molecules and signaling pathways regulate skeletal mechano-transduction involving different bone cells, providing an overview of the IGF-1 signaling mediated cell-specific response to mechanical stimuli. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:576-583, 2018. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.
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Insulin-like growth factor I has independent effects on bone matrix formation and cell replication
DOE Office of Scientific and Technical Information (OSTI.GOV)
Hock, J.M.; Centrella, M.; Canalis, E.
1988-01-01
The effects of insulin-like growth factor-I (IGF-I) and insulin on bone matrix synthesis and bone cell replication were studied in cultured 21-day-old fetal rat calvariae. Histomorphometry techniques were developed to measure the incorporation of (2,3-/sup 3/H)proline and (methyl-/sup 3/H)thymidine into bone matrix and bone cell nuclei, respectively, using autoradiographs of sagittal sections of calvariae cultured with IGF-I, insulin, or vehicle for up to 96 h. To confirm an effect on bone formation, IGF-I was also studied for its effects on (/sup 3/H)proline incorporation into collagenase-digestible protein (CDP) and noncollagen protein and on (/sup 3/H)thymidine incorporation into acid-precipitable material (DNA). IGF-Imore » at 10(-9)-10(-7) M significantly increased the rate of bone matrix apposition and CDP after 24 h by 45-50% and increased cell labeling by 8-fold in the osteoprogenitor cell zone, by 4-fold in the osteoblast cell zone, and by 2-fold in the periosteal fibroblast zone. Insulin at 10(-9)-10(-6) M also increased matrix apposition rate and CDP by 40-50%, but increased cell labeling by 2-fold only at a concentration of 10(-7) M or higher and then only in the osteoprogenitor cell zone. When hydroxyurea was added to IGF-I-treated bones, the effects of IGF-I on DNA synthesis were abolished, but the increase in bone matrix apposition induced by IGF-I was only partly diminished. In conclusion, IGF-I stimulates matrix synthesis in calvariae, an effect that is partly, although not completely, dependent on its stimulatory effect on DNA synthesis.« less
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Frara, Nagat; Abdelmagid, Samir M; Sondag, Gregory R; Moussa, Fouad M; Yingling, Vanessa R; Owen, Thomas A; Popoff, Steven N; Barbe, Mary F; Safadi, Fayez F
2016-01-01
Initial identification of osteoactivin (OA)/glycoprotein non-melanoma clone B (gpnmb) was demonstrated in an osteopetrotic rat model, where OA expression was increased threefold in mutant bones, compared to normal. OA mRNA and protein expression increase during active bone regeneration post-fracture, and primary rat osteoblasts show increased OA expression during differentiation in vitro. To further examine OA/gpnmb as an osteoinductive agent, we characterized the skeletal phenotype of transgenic mouse overexpressing OA/gpnmb under the CMV-promoter (OA-Tg). Western blot analysis showed increased OA/gpnmb in OA-Tg osteoblasts, compared to wild-type (WT). In OA-Tg mouse femurs versus WT littermates, micro-CT analysis showed increased trabecular bone volume and thickness, and cortical bone thickness; histomorphometry showed increased osteoblast numbers, bone formation and mineral apposition rates in OA-Tg mice; and biomechanical testing showed higher peak moment and stiffness. Given that OA/gpnmb is also over-expressed in osteoclasts in OA-Tg mice, we evaluated bone resorption by ELISA and histomorphometry, and observed decreased serum CTX-1 and RANK-L, and decreased osteoclast numbers in OA-Tg, compared to WT mice, indicating decreased bone remodeling in OA-Tg mice. The proliferation rate of OA-Tg osteoblasts in vitro was higher, compared to WT, as was alkaline phosphatase staining and activity, the latter indicating enhanced differentiation of OA-Tg osteoprogenitors. Quantitative RT-PCR analysis showed increased TGF-β1 and TGF-β receptors I and II expression in OA-Tg osteoblasts, compared to WT. Together, these data suggest that OA overexpression has an osteoinductive effect on bone mass in vivo and stimulates osteoprogenitor differentiation ex vivo. © 2015 Wiley Periodicals, Inc.
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Noh, A Long Sae Mi; Yim, Mijung
2011-03-01
Despite numerous reports of the synergistic effects of beta-glycerophosphate and ascorbic acid in inducing the differentiation of osteoblasts, little is known about their roles in osteoclastic differentiation. Therefore, we investigated the effect of beta-glycerophosphate on osteoclastogenesis in the presence of ascorbic acid using primary mouse bone marrow cultures treated with macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor (NF)-kappaB ligand (RANKL). Beta-Glycerophosphate dose-dependently increased RANKL-induced osteoclast formation in the presence of ascorbic acid. This stimulatory effect was apparent when beta-glycerophosphate and ascorbic acid were only added during the late stages of the culture period, indicating that they influence later events in osteoclastic differentiation. While the combination of beta-glycerophosphate and ascorbic acid inhibited RANKL-stimulated activation of ERK and p38, and degradation of IkappaB, it increased the induction of c-Fos and NFATc1. In addition, beta-glycerophosphate and ascorbic acid together enhanced the induction of COX-2 following RANKL stimulation. Taken together, our data suggest that beta-glycerophosphate and ascorbic acid have synergistic effects on osteoclast formation, increasing RANKL-mediated induction of c-Fos, NFATc1 and COX-2 in osteoclast precursors.
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Griffin, X L; Warner, F; Costa, M
2008-04-01
Non-union following long bone fractures is a cause of significant morbidity to the patient. The management of this condition has proved difficult for the orthopaedic surgeon. Much research has been carried out on the use of electromagnetic stimulation in the healing of non-union. The objective of this review is to determine what evidence exists to support electromagnetic stimulation in the management of established non-union of long bone fractures. A systematic search was carried out of the peer-reviewed English language literature to identify all studies investigating electromagnetic stimulation in the treatment of non-union of fractures of long bones. Three of the articles reviewed were randomised clinical trials. Forty-six other studies were also included in the review. There is a consensus that electromagnetic stimulation is an effective adjunct to conventional therapy when used in the management of non-union of long bone fractures.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Moester, Martiene J.C.; Schoeman, Monique A.E.; Oudshoorn, Ineke B.
2014-01-03
Highlights: •We validate a simple and fast method of quantification of in vitro mineralization. •Fluorescently labeled agents can detect calcium deposits in the mineralized matrix of cell cultures. •Fluorescent signals of the probes correlated with Alizarin Red S staining. -- Abstract: Alizarin Red S staining is the standard method to indicate and quantify matrix mineralization during differentiation of osteoblast cultures. KS483 cells are multipotent mouse mesenchymal progenitor cells that can differentiate into chondrocytes, adipocytes and osteoblasts and are a well-characterized model for the study of bone formation. Matrix mineralization is the last step of differentiation of bone cells and ismore » therefore a very important outcome measure in bone research. Fluorescently labelled calcium chelating agents, e.g. BoneTag and OsteoSense, are currently used for in vivo imaging of bone. The aim of the present study was to validate these probes for fast and simple detection and quantification of in vitro matrix mineralization by KS483 cells and thus enabling high-throughput screening experiments. KS483 cells were cultured under osteogenic conditions in the presence of compounds that either stimulate or inhibit osteoblast differentiation and thereby matrix mineralization. After 21 days of differentiation, fluorescence of stained cultures was quantified with a near-infrared imager and compared to Alizarin Red S quantification. Fluorescence of both probes closely correlated to Alizarin Red S staining in both inhibiting and stimulating conditions. In addition, both compounds displayed specificity for mineralized nodules. We therefore conclude that this method of quantification of bone mineralization using fluorescent compounds is a good alternative for the Alizarin Red S staining.« less
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Murphy, Kaitlin C.; Hughbanks, Marissa L.; Binder, Bernard Y.K.; Vissers, Caroline B.; Leach, J. Kent
2014-01-01
Mesenchymal stem/stromal cells (MSCs) are under examination for use in cell therapies to repair bone defects resulting from trauma or disease. MSCs secrete proangiogenic cues and can be induced to differentiate into bone-forming osteoblasts, yet there is limited evidence that these events can be achieved in parallel. Manipulation of the cell delivery vehicle properties represents a candidate approach for directing MSC function in bone healing. We hypothesized that the biophysical properties of a fibrin gel could simultaneously regulate the proangiogenic and osteogenic potential of entrapped MSCs. Fibrin gels were formed by supplementation with NaCl (1.2, 2.3, and 3.9% w/v) to modulate gel biophysical properties without altering protein concentrations. MSCs entrapped in 1.2% w/v NaCl gels were the most proangiogenic in vitro, yet cells in 3.9% w/v gels exhibited the greatest osteogenic response. Compared to the other groups, MSCs entrapped in 2.3% w/v gels provided the best balance between proangiogenic potential, osteogenic potential, and gel contractility. The contribution of MSCs to bone repair was then examined when deployed in 2.3% w/v NaCl gels and implanted into an irradiated orthotopic bone defect. Compared to acellular gels after 3 weeks of implantation, defects treated with MSC-loaded fibrin gels exhibited significant increases in vessel density, early osteogenesis, superior morphology, and increased cellularity of repair tissue. Defects treated with MSC-loaded gels exhibited increased bone formation after 12 weeks compared to blank gels. These results confirm that fibrin gel properties can be modulated to simultaneously promote both the proangiogenic and osteogenic potential of MSCs, and fibrin gels modified by supplementation with NaCl are promising carriers for MSCs to stimulate bone repair in vivo. PMID:25527322
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Sarıtekin, İlker; Açıkgöz, Şerefden; Bayraktaroğlu, Taner; Kuzu, Fatih; Can, Murat; Güven, Berrak; Mungan, Görkem; Büyükuysal, Çağatay; Sarıkaya, Selda
2017-01-01
Sclerostin, which is a glycoprotein produced by osteocytes, reduces the formation of bones by inhibiting the Wnt signal pathway. Thyroid hormones are related with Wnt signal pathway and it has been reported that increased thyroid hormones in hyperthyroidism fasten epiphysis maturation in childhood, and increase the risk of bone fractures by stimulating the bone loss in adults. The aim of this study was to examine the sclerostin serum levels, the relation between sclerostin and thyroid hormones as well as the biochemical markers of the bone metabolism in patients with hyperthyroidism (including multinodular goiter and Graves' disease), whose treatments have not started yet. No difference was found in the serum sclerostin levels between the hyperthyroidism group (n=24) and the control group (n=24) (p=0.452). The serum osteocalcin levels and 24-hour urinary phosphorus excretion were found to be higher in the hyperthyroid group than in the control group (p<0.001, p=0.009). A positive correlation was determined between the sclerostin and bone alkaline phosphatase levels (p<0.001); a negative correlation between the osteocalcin and thyroid stimulating hormone (TSH) (p<0.05); a positive correlation between the osteocalcin and thyroid hormones (FT 3 ,FT 4 ) (p<0.001); and a positive correlation between the deoxypyridinoline and hydroxyproline (p<0.001). No correlation was determined between sclerostin and TSH,FT 3 ,FT 4 (p>0.05). Therefore, we consider that a long-term study that covers the pre-post treatment stages of hyperthyroidism, including both the destruction and construction of the skeleton would be more enlightening. Moreover, the assessment of the synthesis of sclerostin in the bone tissue and in the serum level might show differences.
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Zhang, Zhonglei; Ma, Yalin; Guo, Shaowen; He, Yi; Bai, Gang; Zhang, Wenjun
2018-05-29
Low-intensity pulsed ultrasound (LIPUS) has positive effects on osteogenic differentiation. However, the effect of LIPUS on osteogenic differentiation of human adipose-derived stem cells (hASCs) is unclear. In the present study, we investigated whether LIPUS could promote the proliferation and osteogenic differentiation of hASCs. hASCs were isolated and osteogenically induced with LIPUS stimulation at 20 and 30 mW cm -2 for 30 min day -1 Cell proliferation and osteogenic differentiation potential of hASCs were respectively analyzed by cell counting kit-8 assay, Alizarin Red S staining, real-time polymerase chain reaction, and Western blotting. The results indicated that LIPUS stimulation did not significantly affect the proliferation of hASCs, but significantly increased their alkaline phosphatase activity on day 6 of culture and markedly promoted the formation of mineralized nodules on day 21 of culture. The mRNA expression levels of runt-related transcription factor, osteopontin, and osteocalcin were significantly up-regulated by LIPUS stimulation. LIPUS stimulation did not affect the expression of heat shock protein (HSP) 27, HSP40, bone morphogenetic protein (BMP)-6 and BMP-9, but significantly up-regulated the protein levels of HSP70, HSP90, BMP-2, and BMP-7 in the hASCs. Further studies found that LIPUS increased the mRNA levels of Smad 1 and Smad 5, elevated the phosphorylation of Smad 1/5, and suppressed the expression of BMP antagonist Noggin. These findings indicated that LIPUS stimulation enhanced osteogenic differentiation of hASCs possibly through the up-regulation of HSP70 and HSP90 expression and activation of BMP signaling pathway. Therefore, LIPUS might have the potential to promote the repair of bone defect. © 2018 The Author(s).
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IL-17 receptor A signaling is protective in infection-stimulated periapical bone destruction.
AlShwaimi, Emad; Berggreen, Ellen; Furusho, Hisako; Rossall, Jonathan Caleb; Dobeck, Justine; Yoganathan, Subbiah; Stashenko, Philip; Sasaki, Hajime
2013-08-15
IL-17 is a pleiotropic cytokine produced by Th17 T cells that induces a myriad of proinflammatory mediators. However, different models of inflammation report opposite functional roles of IL-17 signal in terms of its effects on bone destruction. In this study we determined the role of IL-17RA signal in bone resorption stimulated by dentoalveolar infections. Infrabony resorptive lesions were induced by surgical pulp exposure and microbial infection of mouse molar teeth. IL-17 was strongly induced in periapical tissues in wild-type (WT) mice by 7 d after the infection but was not expressed in uninfected mice. Dentoalveolar infections of IL-17RA knockout (KO) mice demonstrated significantly increased bone destruction and more abscess formation in the apical area compared with WT mice. Infected IL-17RA KO mice exhibited significantly increased neutrophils and macrophages compared with the WT littermates at day 21, suggesting a failure of transition from acute to chronic inflammation in the IL-17RA KO mice. The expression of IL-1 (both α and β isoforms) and MIP2 were significantly upregulated in the IL-17RA KO compared with WT mice at day 21 postinfection. The development of periapical lesions in IL-17RA KO mice was significantly attenuated by neutralization of IL-1β and MIP2. Taken together, these results demonstrate that IL-17RA signal seems to be protective against infection-induced periapical inflammation and bone destruction via suppression of neutrophil and mononuclear inflammation.
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Human mesenchymal stromal cells are mechanosensitive to vibration stimuli.
Kim, I S; Song, Y M; Lee, B; Hwang, S J
2012-12-01
Low-magnitude high-frequency (LMHF) vibrations have the ability to stimulate bone formation and reduce bone loss. However, the anabolic mechanisms that are mediated by vibration in human bone cells at the cellular level remain unclear. We hypothesized that human mesenchymal stromal cells (hMSCs) display direct osteoblastic responses to LMHF vibration signals. Daily exposure to vibrations increased the proliferation of hMSCs, with the highest efficiency occurring at a peak acceleration of 0.3 g and vibrations at 30 to 40 Hz. Specifically, these conditions promoted osteoblast differentiation through an increase in alkaline phosphatase activity and in vitro matrix mineralization. The effect of vibration on the expression of osteogenesis-related factors differed depending on culture method. hMSCs that underwent vibration in a monolayer culture did not exhibit any changes in the expressions of these genes, while cells in three-dimensional culture showed increased expression of type I collagen, osteoprotegerin, or VEGF, and VEGF induction appeared in 2 different hMSC lines. These results are among the first to demonstrate a dose-response effect upon LMHF stimulation, thereby demonstrating that hMSCs are mechanosensitive to LMHF vibration signals such that they could facilitate the osteogenic process.
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Bone Marrow Aspirate Concentrate-Enhanced Marrow Stimulation of Chondral Defects
Eichler, Hermann; Orth, Patrick
2017-01-01
Mesenchymal stem cells (MSCs) from bone marrow play a critical role in osteochondral repair. A bone marrow clot forms within the cartilage defect either as a result of marrow stimulation or during the course of the spontaneous repair of osteochondral defects. Mobilized pluripotent MSCs from the subchondral bone migrate into the defect filled with the clot, differentiate into chondrocytes and osteoblasts, and form a repair tissue over time. The additional application of a bone marrow aspirate (BMA) to the procedure of marrow stimulation is thought to enhance cartilage repair as it may provide both an additional cell population capable of chondrogenesis and a source of growth factors stimulating cartilage repair. Moreover, the BMA clot provides a three-dimensional environment, possibly further supporting chondrogenesis and protecting the subchondral bone from structural alterations. The purpose of this review is to bridge the gap in our understanding between the basic science knowledge on MSCs and BMA and the clinical and technical aspects of marrow stimulation-based cartilage repair by examining available data on the role and mechanisms of MSCs and BMA in osteochondral repair. Implications of findings from both translational and clinical studies using BMA concentrate-enhanced marrow stimulation are discussed. PMID:28607559
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Treatment feasibility study of osteoporosis using minimal invasive laser needle system
NASA Astrophysics Data System (ADS)
Kang, Dongyeon; Ko, Chang-Yong; Ryu, Yeon-Hang; Park, Sunwook; Kim, Han-Sung; Jung, Byungjo
2010-02-01
Although the mechanism of laser stimulation effect in bone has not completely understood, laser stimulation is recommended in the treatment of osteoporosis due to positive treatment efficacy. In this study, a minimal invasive laser needle system (MILNS) was developed using a fine hollow needle in order to stimulate directly bone site by guiding an optical fiber. In order to evaluate the MILNS as a treatment method, in-vivo animal experiment study was performed using osteopenic mice. Twelve virginal ICR mice were employed and divided two groups: SHAM-group and LASERgroup. SHARM-group was stimulated by only fine hollow needle and LASER-group by fine hollow needle combined with laser stimulation. All mice were served in-vivo micro-CT images before and after treatment. Three dimensional (3D) structural parameters and vBMD (volume bone mineral density, g/cm3) in the trabecular bone were measured. After 2 weeks of stimulation, the vBMD, BV/TV, Tb.Th and Tb.N in LASER-group were significantly higher than those in SHAM-group (p<0.05). Potentially, this study suggested that the MILNS might prevent the bone loss and maintains the bone mineral density of osteopenic mice.
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Koide, M; Okahashi, N; Tanaka, R; Kazuno, K; Shibasaki, K; Yamazaki, Y; Kaneko, K; Ueda, N; Ohguchi, M; Ishihara, Y; Noguchi, T; Nishihara, T
1999-09-01
It is known that bone resorption is mediated by osteoclasts, and lipopolysaccharide (LPS) and inflammatory mediators such as interleukin-1 (IL-1) and prostaglandin E2 (PGE2) induce osteoclast differentiation from haemopoietic cells, 2-aminoethanesulphonic acid, which is known as taurine, is an important nutrient and is added to most synthetic human infant milk formulas. In this study, it was found that 2-aminoethanesulphonic acid inhibits the stimulation of bone resorption mediated by LPS of the periodontopathic microorganism Actinobacillus actinomycetemcomitans Y4 in organ cultures of newborn mouse calvaria. The effect of 2-aminoethanesulphonic acid on the development and survival of osteoclast-like multinucleated cells produced in a mouse bone-marrow culture system was also examined. 2-aminoethanesulphonic acid (100 microg/ml) suppressed the formation of these osteoclast-like cells in the presence of LPS of A. actinomycetemcomitans Y4, IL-1alpha or PGE2 in mouse marrow cultures. On the other hand, 2-aminoethanesulphonic acid did not inhibit 1alpha, 25-dihydroxyvitamin D3-mediated osteoclast differentiation. Although IL-1alpha elongated the survival of the osteoclast-like cells, 2-aminoethanesulphonic acid blocked the supportive effect of IL-1alpha on osteoclast survival. 2-aminoethanesulphonic acid showed no effect on the growth of mouse osteoblasts. Finally, it was found that 2-aminoethanesulphonic acid inhibited alveolar bone resorption in experimental periodontitis in hamsters. These results suggest that 2-aminoethanesulphonic acid is an effective agent in preventing inflammatory bone resorption in periodontal diseases.
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Cardiotonic agent milrinone stimulates resorption in rodent bone organ culture.
Krieger, N S; Stappenbeck, T S; Stern, P H
1987-01-01
The cardiotonic agent amrinone inhibits bone resorption in vitro. Milrinone, an amrinone analog, is a more potent cardiotonic agent with lower toxicity. In contrast to amrinone, milrinone stimulated resorption in cultures of neonatal mouse calvaria and fetal rat limb bones. Threshold doses were 0.1 microM in calvaria and 0.1 mM in limb bones; maximal stimulation occurred in calvaria at 0.1 mM. Maximal responses to milrinone and parathyroid hormone were comparable. Milrinone concentrations below 0.1 mM did not affect calvarial cyclic AMP. 0.5 microM indomethacin inhibited milrinone effects in calvaria but usually not in limb bones. 3 nM calcitonin inhibited milrinone-stimulated resorption and there was no escape from this inhibition. Structural homology between milrinone and thyroxine has been reported. We find similarities between milrinone and thyroxine actions on bone, because prostaglandin production was crucial for the effects of both agents in calvaria but not in limb bones, and neither agent exhibited escape from calcitonin inhibition. PMID:3027124
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Effects of obesity on bone metabolism.
Cao, Jay J
2011-06-15
Obesity is traditionally viewed to be beneficial to bone health because of well-established positive effect of mechanical loading conferred by body weight on bone formation, despite being a risk factor for many other chronic health disorders. Although body mass has a positive effect on bone formation, whether the mass derived from an obesity condition or excessive fat accumulation is beneficial to bone remains controversial. The underline pathophysiological relationship between obesity and bone is complex and continues to be an active research area. Recent data from epidemiological and animal studies strongly support that fat accumulation is detrimental to bone mass. To our knowledge, obesity possibly affects bone metabolism through several mechanisms. Because both adipocytes and osteoblasts are derived from a common multipotential mesenchymal stem cell, obesity may increase adipocyte differentiation and fat accumulation while decrease osteoblast differentiation and bone formation. Obesity is associated with chronic inflammation. The increased circulating and tissue proinflammatory cytokines in obesity may promote osteoclast activity and bone resorption through modifying the receptor activator of NF-κB (RANK)/RANK ligand/osteoprotegerin pathway. Furthermore, the excessive secretion of leptin and/or decreased production of adiponectin by adipocytes in obesity may either directly affect bone formation or indirectly affect bone resorption through up-regulated proinflammatory cytokine production. Finally, high-fat intake may interfere with intestinal calcium absorption and therefore decrease calcium availability for bone formation. Unraveling the relationship between fat and bone metabolism at molecular level may help us to develop therapeutic agents to prevent or treat both obesity and osteoporosis. Obesity, defined as having a body mass index ≥ 30 kg/m2, is a condition in which excessive body fat accumulates to a degree that adversely affects health. The rates of obesity rates have doubled since 1980 and as of 2007, 33% of men and 35% of women in the US are obese. Obesity is positively associated to many chronic disorders such as hypertension, dyslipidemia, type 2 diabetes mellitus, coronary heart disease, and certain cancers. It is estimated that the direct medical cost associated with obesity in the United States is ~$100 billion per year.Bone mass and strength decrease during adulthood, especially in women after menopause. These changes can culminate in osteoporosis, a disease characterized by low bone mass and microarchitectural deterioration resulting in increased bone fracture risk. It is estimated that there are about 10 million Americans over the age of 50 who have osteoporosis while another 34 million people are at risk of developing the disease. In 2001, osteoporosis alone accounted for some $17 billion in direct annual healthcare expenditure. Several lines of evidence suggest that obesity and bone metabolism are interrelated. First, both osteoblasts (bone forming cells) and adipocytes (energy storing cells) are derived from a common mesenchymal stem cell and agents inhibiting adipogenesis stimulated osteoblast differentiation and vice versa, those inhibiting osteoblastogenesis increased adipogenesis. Second, decreased bone marrow osteoblastogenesis with aging is usually accompanied with increased marrow adipogenesis. Third, chronic use of steroid hormone, such as glucocorticoid, results in obesity accompanied by rapid bone loss. Fourth, both obesity and osteoporosis are associated with elevated oxidative stress and increased production of proinflammatory cytokines. At present, the mechanisms for the effects of obesity on bone metabolism are not well defined and will be the focus of this review.
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Kong, Xiangying; Wu, Wenbin; Yang, Yue; Wan, Hongye; Li, Xiaomin; Zhong, Michun; Zhao, Hongyan; Su, Xiaohui; Jia, Shiwei; Ju, Dahong; Lin, Na
2015-03-15
Osteoclasts, bone-specialized multinucleated cells, are responsible for bone destructive diseases such as rheumatoid arthritis and osteoporosis. Natural plant-derived products have received substantial attention given their potential therapeutic and preventive activities against bone destructive diseases. In the present study, we investigated the effects of total saponin (TS) from Anemone flaccida Fr. Schmidt, on receptor activator of nuclear factor-κB ligand (RANKL)-induced in vitro osteoclast differentiation. We observed that TS concentration-dependently inhibited RANKL-induced osteoclast formation from RAW 264.7 cell and bone marrow-derived macrophages (BMMs), as well as decreased extent of actin ring formation and lacunar resorption. The RANKL-stimulated expression of osteoclast-related transcription factors were also diminished by TS. Moreover, TS blocked the RANKL-triggered TRAF6 expression, phosphorylation of mitogen-activated protein kinases (MAPKs) and IκB-α, and inhibited NF-κB p65 DNA binding activity. Furthermore, TS almost abrogated the nuclear factor of activated T cells (NFATc1) and c-Fos expression. Taken together, our results demonstrated that TS suppresses RANKL-induced osteoclast differentiation and inflammatory bone loss via the down-regulation of TRAF6 level, suppression of JNK and p38 MAPKs and NF-κB activation, and subsequent decreased expression of c-Fos and NFATc1. Therefore, TS may be a potential agent and needs to be more evaluated in vivo or in clinical trials to become a therapeutic for lytic bone diseases.
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Preininger, Bernd; Duda, Georg; Gerigk, Hinnerk; Bruckner, Jonas; Ellinghaus, Agnes; Sass, F. Andrea; Perka, Carsten; Schmidt-Bleek, Katharina; Dienelt, Anke
2013-01-01
Sufficient angiogenesis is crucial during tissue regeneration and therefore also pivotal in bone defect healing. Recently, peripheral blood derived progenitor cells have been identified to have in addition to their angiogenic potential also osteogenic characteristics, leading to the hypothesis that bone regeneration could be stimulated by local administration of these cells. The aim of this study was to evaluate the angiogenic potential of locally administered progenitor cells to improve bone defect healing. Cells were separated from the peripheral blood of donor animals using the markers CD34 and CD133. Results of the in vitro experiments confirmed high angiogenic potential in the CD133(+) cell group. CD34(+) and CD133(+) cells were tested in an in vivo rat femoral defect model of delayed healing for their positive effect on the healing outcome. An increased callus formation and higher bone mineral density of callus tissue was found after the CD133(+) cell treatment compared to the group treated with CD34(+) cells and the control group without cells. Histological findings confirmed an increase in vessel formation and mineralization at day 42 in the osteotomy gap after CD133(+) cell transplantation. The higher angiogenic potential of CD133(+) cells from the in vitro experients therefore correlates with the in vivo data. This study demonstrates the suitability of angiogenic precursors to further bone healing and gives an indication that peripheral blood is a promising source for progenitor cells circumventing the problems associated with bone marrow extraction. PMID:23457441
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Denosumab in Postmenopausal Osteoporosis: What the Clinician Needs to Know
Lewiecki, E. Michael
2009-01-01
Denosumab is a subcutaneously (SC) administered investigational fully human monoclonal antibody to receptor activator of nuclear factor-kB ligand (RANKL), a cytokine member of the tumor necrosis factor family that is the principal mediator of osteoclastic bone resorption. RANKL stimulates the formation, activity, and survival of osteoclasts, and is implicated in the pathogenesis of postmenopausal osteoporosis and other skeletal disorders associated with increased bone remodeling. Denosumab binds RANKL, preventing it from binding to RANK, thereby reducing the formation, activity, and survival of osteoclasts and slowing the rate of bone resorption. Postmenopausal women with low bone mineral density (BMD) treated with denosumab have a reduction of bone turnover markers and an increase in BMD that is rapid, sustained, and reversible. In postmenopausal women with osteoporosis, denosumab reduces the risk of vertebral, hip, and nonvertebral fractures. In postmenopausal women with low BMD randomized to receive denosumab or alendronate, denosumab is associated with a significantly greater increase in BMD and further reduction in bone turnover markers compared with alendronate. In postmenopausal women with low BMD who were previously treated with alendronate, those who switched to denosumab have a significantly greater BMD increase and further reduction in bone turnover markers compared with those continuing alendronate. Denosumab is well tolerated with a favorable safety profile. It is a promising emerging drug for the prevention and treatment of osteoporosis, offering a long dosing interval of every 6 months and convenient SC dosing, with the potential of improving long-term adherence to therapy compared with current oral treatments. PMID:22870424
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[Study of migration and distribution of bone marrow cells transplanted animals with B16 melanoma ].
Poveshchenko, A F; Solovieva, A O; Zubareva, K E; Strunkin, D N; Gricyk, O B; Poveshchenko, O V; Shurlygina, A V; Konenkov, V I
2017-01-01
Purpose. Reveal features migration and distribution of syngeneic bone marrow cells (BMC) and subpopulations (MSC) after transplantation into the recipient carrier B16 melanoma bodies. Methods. We used mouse male and female C57BL/6 mice. Induction of Tumor Growth: B16 melanoma cells implanted subcutaneously into right hind paw of female C57BL/6 mice at a dose of 2.5 x 105 cells / mouse. migration study in vivo distribution and BMC and MSC was performed using genetic markers - Y-chromosome specific sequence line male C57Bl/6 syngeneic intravenous transplantation in females using the polymerase chain reaction (PCR) in real time on Authorized Termal Cycler - Light Cycler 480 II / 96 (Roche). Introduction suspension of unseparated bone marrow cells, mesenchymal stem cells from donor to recipient male mice (syngeneic recipient female C57BL/6), followed by isolation of recipients of organs was performed at regular intervals, then of organ recipients isolated DNA. Results. It was shown that bone marrow cells positive for Y-chromosome in migrate lymphoid (lymph nodes, spleen, bone marrow) or in non-lymphoid organs (liver, heart, brain, skin) syngeneic recipients. In addition to the migration of cells from the bone marrow to other organs, there is a way back migration of cells from the circulation to the bone marrow. B16 melanoma stimulates the migration of transplanted MSCs and BMC in bone marrow. It is found that tumor growth enhanced migration of transplanted bone marrow cells, including populations of MSCs in the bone marrow. In the early stages of tumor formation MSC migration activity higher than the BMC. In the later stages of tumor formation undivided population of bone marrow cells migrate to the intense swelling compared with a population of MSCs. Conclusion. The possibility of using bone marrow MSCs for targeted therapy of tumor diseases, because migration of MSCs in tumor tissue can be used to effectively deliver anticancer drugs.
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Does methamphetamine affect bone metabolism?
Tomita, Masafumi; Katsuyama, Hironobu; Watanabe, Yoko; Okuyama, Toshiko; Fushimi, Shigeko; Ishikawa, Takaki; Nata, Masayuki; Miyamoto, Osamu
2014-05-07
There is a close relationship between the central nervous system activity and bone metabolism. Therefore, methamphetamine (METH), which stimulates the central nervous system, is expected to affect bone turnover. The aim of this study was to investigate the role of METH in bone metabolism. Mice were divided into 3 groups, the control group receiving saline injections, and the 5 and 10mg/kg METH groups (n=6 in each group). All groups received an injection of saline or METH every other day for 8 weeks. Bone mineral density (BMD) was assessed by X-ray computed tomography. We examined biochemical markers and histomorphometric changes in the second cancellous bone of the left femoral distal end. The animals that were administered 5mg/kg METH showed an increased locomotor activity, whereas those receiving 10mg/kg displayed an abnormal and stereotyped behavior. Serum calcium and phosphorus concentrations were normal compared to the controls, whereas the serum protein concentration was lower in the METH groups. BMD was unchanged in all groups. Bone formation markers such as alkaline phosphatase and osteocalcin significantly increased in the 5mg/kg METH group, but not in the 10mg/kg METH group. In contrast, bone resorption markers such as C-terminal telopeptides of type I collagen and tartrate-resistant acid phosphatase 5b did not change in any of the METH groups. Histomorphometric analyses were consistent with the biochemical markers data. A significant increase in osteoblasts, especially in type III osteoblasts, was observed in the 5mg/kg METH group, whereas other parameters of bone resorption and mineralization remained unchanged. These results indicate that bone remodeling in this group was unbalanced. In contrast, in the 10mg/kg METH group, some parameters of bone formation were significantly or slightly decreased, suggesting a low turnover metabolism. Taken together, our results suggest that METH had distinct dose-dependent effects on bone turnover and that METH might induce adverse effects, leading to osteoporosis. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.
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Evaluation of Cameroonian plants towards experimental bone regeneration.
Ngueguim, Florence Tsofack; Khan, Mohd Parvez; Donfack, Jean Hubert; Siddiqui, Jawed Akhtar; Tewari, Deepshikha; Nagar, Geet K; Tiwari, Satish C; Theophile, Dimo; Maurya, Rakesh; Chattopadhyay, Naibedya
2012-05-07
Elephantopus mollis, Spilanthes africana, Urena lobata, Momordica multiflora, Asystasia gangetica and Brillantaisia ovariensis are used in Cameroonian traditional medicine for the treatment of bone diseases and fracture repair. The aim of this study was to evaluate the effect of ethanolic extracts of six Cameroonian medicinal plants on bone regeneration following bone and marrow injury. Ethanol extract of Cameroonian medicinal plants were administered (each extract at 250, 500 and 750mg/kg doses) orally to adult female Sprague-Dawley rats having a drill hole injury (0.8mm) in the femur diaphysis. Vehicle (gum-acacia in distilled water) was given to the control group. After 12 days of treatment, animals were euthanized and femur bones collected. Confocal microscopy of fractured bone was performed to evaluate bone regeneration (calcein labeling). Only active plant extracts were used for further experiments. Thus, callus was analyzed by microcomputed tomography. Osteogenic effects of the extracts were evaluated by assessing mineralized nodules formation of bone marrow stromal cells and osteoblast recruitment at drill hole site by immunohistochemistry. Ethanolic extract of the leaves and twigs of Elephantopus mollis (EM) and whole plant of Spilanthes africana (SA) dose-dependently stimulated bone regeneration at the drill hole site. EM at 250 and 750mg/kg doses and SA at 750mg/kg dose significantly increased mineral deposition compared to controls. Both extracts at 500 and 750mg/kg doses improved microarchitecture of the regenerating bone evident from increased bone volume fraction, trabecular thickness, trabecular number, and decreased trabecular separation and structure model index. EM and SA extracts increased the formation of mineralized nodules from the bone marrow stromal cells. In addition, EM and SA extracts increased osteoblast recruitment at the drill hole site evident from increased Runx-2 positive cells following their treatments compared to control. Ethanolic extracts of EM and SA accelerate fracture repair in rats via stimulatory effects on osteoblast differentiation and mineralization, thereby justifying their traditional use. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.
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Incorporation of RANKL promotes osteoclast formation and osteoclast activity on β-TCP ceramics.
Choy, John; Albers, Christoph E; Siebenrock, Klaus A; Dolder, Silvia; Hofstetter, Wilhelm; Klenke, Frank M
2014-12-01
β-Tricalcium phosphate (β-TCP) ceramics are approved for the repair of osseous defects. In large defects, however, the substitution of the material by authentic bone is inadequate to provide sufficient long-term mechanical stability. We aimed to develop composites of β-TCP ceramics and receptor activator of nuclear factor κ-B ligand (RANKL) to enhance the formation of osteoclasts and promote cell mediated calcium phosphate resorption. RANKL was adsorbed superficially onto β-TCP ceramics or incorporated into a crystalline layer of calcium phosphate by the use of a co-precipitation technique. Murine osteoclast precursors were seeded onto the ceramics. After 15 days, the formation of osteoclasts was quantified cytologically and colorimetrically with tartrate-resistant acidic phosphatase (TRAP) staining and TRAP activity measurements, respectively. Additionally, the expression of transcripts encoding the osteoclast gene products cathepsin K, calcitonin receptor, and of the sodium/hydrogen exchanger NHA2 were quantified by real-time PCR. The activity of newly formed osteoclasts was evaluated by means of a calcium phosphate resorption assay. Superficially adsorbed RANKL did not induce the formation of osteoclasts on β-TCP ceramics. When co-precipitated onto β-TCP ceramics RANKL supported the formation of mature osteoclasts. The development of osteoclast lineage cells was further confirmed by the increased expression of cathepsin K, calcitonin receptor, and NHA2. Incorporated RANKL stimulated the cells to resorb crystalline calcium phosphate. Our in vitro study shows that RANKL incorporated into β-TCP ceramics induces the formation of active, resorbing osteoclasts on the material surface. Once formed, osteoclasts mediate the release of RANKL thereby perpetuating their differentiation and activation. In vivo, the stimulation of osteoclast-mediated resorption may contribute to a coordinated sequence of material resorption and bone formation. Further in vivo studies are needed to confirm the current in vitro findings. Copyright © 2014 Elsevier Inc. All rights reserved.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Arana, Lide; Gangoiti, Patricia; Ouro, Alberto
2012-02-15
We previously demonstrated that ceramide 1-phosphate (C1P) is mitogenic for fibroblasts and macrophages. However, the mechanisms involved in this action were only partially described. Here, we demonstrate that C1P stimulates reactive oxygen species (ROS) formation in primary bone marrow-derived macrophages, and that ROS are required for the mitogenic effect of C1P. ROS production was dependent upon prior activation of NADPH oxidase by C1P, which was determined by measuring phosphorylation of the p40phox subunit and translocation of p47phox from the cytosol to the plasma membrane. In addition, C1P activated cytosolic calcium-dependent phospholipase A{sub 2} and protein kinase C-{alpha}, and NADPH oxidasemore » activation was blocked by selective inhibitors of these enzymes. These inhibitors, and inhibitors of ROS production, blocked the mitogenic effect of C1P. By using BHNB-C1P (a photolabile caged-C1P analog), we demonstrate that all of these C1P actions are caused by intracellular C1P. It can be concluded that the enzyme responsible for C1P-stimulated ROS generation in bone marrow-derived macrophages is NADPH oxidase, and that this enzyme is downstream of PKC-{alpha} and cPLA{sub 2}-{alpha} in this pathway. -- Highlights: Black-Right-Pointing-Pointer Ceramide 1-phosphate (C1P) stimulates reactive oxygen species (ROS) formation. Black-Right-Pointing-Pointer The enzyme responsible for ROS generation by C1P in macrophages is NADPH oxidase. Black-Right-Pointing-Pointer NADPH oxidase lies downstream of cPLA{sub 2}-{alpha} and PKC-{alpha} in this pathway. Black-Right-Pointing-Pointer ROS generation is essential for the stimulation of macrophage proliferation by C1P.« less
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NASA Astrophysics Data System (ADS)
Barcikowski, Stephan; Hahn, Anne; Guggenheim, Merlin; Reimers, Kerstin; Ostendorf, Andreas
2010-06-01
Nanoactuators made from nanoparticulate NiTi shape memory alloy show potential in the mechanical stimulation of bone tissue formation from stem cells. We demonstrate the fabrication of Ni, Ti, and NiTi shape memory alloy nanoparticles and their biocompatibility to human adipose-derived stem cells. The stoichiometry and phase transformation property of the bulk alloy is preserved during attrition by femtosecond laser ablation in liquid, giving access to colloidal nanoactuators. No adverse effect on cell growth and attachment is observed in proliferation assay and environmental electron scanning microscopy, making this material attractive for mechanical stimulation of stem cells.
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Iryanov, Y M; Kiryanov, N A
2015-01-01
Non-drug correction of reparative bone tissue regeneration in different pathological states - one of the most actual problems of modern medicine. Our aim was to conduct morphological analysis of the influence of electromagnetic radiation of ultra-high frequency and low intensity on reparative osteogenesis and angiogenesis in fracture treatment under transosseous osteosynthesis. A controlled nonrandomized study was carried out. In the experiment conducted on rats we modeled tibial fracture with reposition and fixation of the bone fragments both in control and experimental groups. In the animals of the experimental group the fracture zone was exposed to low intensity electromagnetic radiation of ultra-high frequency. Exposure simulation was performed in the control group. The operated bones were examined using radiography, light and electronic microscopy, X-ray electronic probe microanalysis. It has been established that electromagnetic radiation of ultra-high frequency sessions in fracture treatment stimulate secretory activity and degranulation of mast cells, produce microcirculatory bed vascular permeability increase, endotheliocyte migration phenotype expression, provide endovascular endothelial outgrowth formation, activate reparative osteogenesis and angiogenesis while fracture reparation becomes the one of the primary type. The full periosteal, intermediary and intraosteal bone union was defined in 28 days. Among the therapeutic benefits of electromagnetic radiation of ultra-high frequency in fracture treatment we can detect mast cell secretorv activity stimulation and endovascular anziozenesis activation.
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Qi, Zhiping; Xia, Peng; Pan, Su; Zheng, Shuang; Fu, Chuan; Chang, Yuxin; Ma, Yue; Wang, Jincheng; Yang, Xiaoyu
2018-01-01
Electrical stimulation (ES) and insulin-like growth factor-1 (IGF-1) are widely used in bone regeneration because of their osteogenic activity. However, the combined effects of ES and supplemental IGF-1 on the whole bone formation process remain unclear. In this study, fluorescence staining and an MTT assay were first utilized to observe the influence of ES and IGF-1 on MC3T3-E1 cell proliferation and adhesion in vitro. Subsequently, osteogenic differentiation was evaluated by the alkaline phosphatase activity (ALP) and the expression of osteogenic marker genes. In addition, cell mineralization was determined by alizarin red staining and scanning electron microscopy (SEM). We demonstrated that the MC3T3-E1 cell proliferation was significantly higher for treatments combining IGF-1 and ES than for treatments with IGF-1 alone. The combination of IGF-1 and ES increased the MC3T3-E1 cell ALP activity, the expression of osteogenesis-related genes and the calcium deposition with a clear dose-dependent effect. Our data show the synergistic effect of IGF-1 and ES in promoting the proliferation, differentiation and mineralization of MC3T3-E1 cells, which suggests that it would be more effective to combine the proper dose of IGF-1 with ES to promote local bone damage repair and regeneration.
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Tseng, Wendy; Graham, Lucia S; Geng, Yifan; Reddy, Aneela; Lu, Jinxiu; Effros, Rita B; Demer, Linda; Tintut, Yin
2010-09-24
Vascular calcification is a predictor of cardiovascular mortality and is prevalent in patients with atherosclerosis and chronic renal disease. It resembles skeletal osteogenesis, and many bone cells as well as bone-related factors involved in both formation and resorption have been localized in calcified arteries. Previously, we showed that aortic medial cells undergo osteoblastic differentiation and matrix calcification both spontaneously and in response to PKA agonists. The PKA signaling pathway is also involved in regulating bone resorption in skeletal tissue by stimulating osteoblast-production of osteoclast regulating cytokines, including receptor-activator of nuclear κB ligand (RANKL) and interleukins. Therefore, we investigated whether PKA activators regulate osteoclastogenesis in aortic smooth muscle cells (SMC). Treatment of murine SMC with the PKA agonist forskolin stimulated RANKL expression at both mRNA and protein levels. Forskolin also stimulated expression of interleukin-6 but not osteoprotegerin (OPG), an inhibitor of RANKL. Consistent with these results, osteoclastic differentiation was induced when monocytic preosteoclasts (RAW264.7) were cocultured with forskolin-treated aortic SMC. Oxidized phospholipids also slightly induced RANKL expression in T lymphocytes, another potential source of RANKL in the vasculature. Because previous studies have shown that RANKL treatment alone induces matrix calcification of valvular and vascular cells, we next examined whether RANKL mediates forskolin-induced matrix calcification by aortic SMC. RANKL inhibition with OPG had little or no effect on osteoblastic differentiation and matrix calcification of aortic SMC. These findings suggest that, as in skeletal tissues, PKA activation induces bone resorptive factors in the vasculature and that aortic SMC calcification specifically induced by PKA, is not mediated by RANKL.
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Carbon Nanoparticle Enhance Photoacoustic Imaging and Therapy for Bone Tissue Engineering
NASA Astrophysics Data System (ADS)
Talukdar, Yahfi
Healing critical sized bone defects has been a challenge that led to innovations in tissue engineering scaffolds and biomechanical stimulations that enhance tissue regeneration. Carbon nanocomposite scaffolds have gained interest due to their enhanced mechanical properties. However, these scaffolds are only osteoconductive and not osteoinductive. Stimulating regeneration of bone tissue, osteoinductivity, has therefore been a subject of intense research. We propose the use of carbon nanoparticle enhanced photoacoustic (PA) stimulation to promote and enhance tissue regeneration in bone tissue-engineering scaffolds. In this study we test the feasibility of using carbon nanoparticles and PA for in vivo tissue engineering applications. To this end, we investigate 1) the effect of carbon nanoparticles, such as graphene oxide nanoplatelets (GONP), graphene oxide nano ribbons (GONR) and graphene nano onions (GNO), in vitro on mesenchymal stem cells (MSC), which are crucial for bone regeneration; 2) the use of PA imaging to detect and monitor tissue engineering scaffolds in vivo; and 3) we demonstrate the potential of carbon nanoparticle enhanced PA stimulation to promote tissue regeneration and healing in an in vivo rat fracture model. The results from these studies demonstrate that carbon nanoparticles such as GNOP, GONR and GNO do not affect viability or differentiation of MSCs and could potentially be used in vivo for tissue engineering applications. Furthermore, PA imaging can be used to detect and longitudinally monitor subcutaneously implanted carbon nanotubes incorporated polymeric nanocomposites in vivo. Oxygen saturation data from PA imaging could also be used as an indicator for tissue regeneration within the scaffolds. Lastly, we demonstrate that daily stimulation with carbon nanoparticle enhanced PA increases bone fracture healing. Rats stimulated for 10 minutes daily for two weeks showed 3 times higher new cortical bone BV/TV and 1.8 times bone mineral density, compared to non-stimulated controls. The results taken together indicate that carbon nanoparticle enhanced PA stimulation serves as an anabolic stimulus for bone regeneration. The results suggest opportunities towards the development of implant device combination therapies for bone loss due to disease or trauma.
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Dawson, Lindsay A.; Yu, Ling; Yan, Mingquan; Marrero, Luis; Schanes, Paula P.; Dolan, Connor; Pela, Maegan; Petersen, Britta; Han, Manjong
2017-01-01
Abstract Regeneration of mammalian limbs is restricted to amputation of the distal digit tip, the terminal phalanx (P3). The adjacent skeletal element, the middle phalanx (P2), has emerged as a model system to investigate regenerative failure and as a site to test approaches aimed at enhancing regeneration. We report that exogenous application of bone morphogenetic protein 2 (BMP2) stimulates the formation of a transient cartilaginous callus distal to the amputation plane that mediates the regeneration of the amputated P2 bone. BMP2 initiates a significant regeneration response during the periosteal‐derived cartilaginous healing phase of P2 bone repair, yet fails to induce regeneration in the absence of periosteal tissue, or after boney callus formation. We provide evidence that a temporal component exists in the induced regeneration of P2 that we define as the “regeneration window.” In this window, cells are transiently responsive to BMP2 after the amputation injury. Simple re‐injury of the healed P2 stump acts to reinitiate endogenous bone repair, complete with periosteal chondrogenesis, thus reopening the “regeneration window” and thereby recreating a regeneration‐permissive environment that is responsive to exogenous BMP2 treatment. PMID:28975034
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Arepalli, Sampath Kumar; Tripathi, Himanshu; Hira, Sumit Kumar; Manna, Partha Pratim; Pyare, Ram; S P Singh
2016-12-01
Strontium contained biomaterials have been reported as a potential bioactive material for bone regeneration, as it reduces bone resorption and stimulates bone formation. In the present investigation, the bioactive glasses were designed to partially substitute SrO for SiO2 in Na2O-CaO-SrO-P2O5-SiO2 system. This work demonstrates that the substitution of SrO for SiO2 has got significant benefit than substitution for CaO in the bioactive glass. Bioactivity was assessed by the immersion of the samples in simulated body fluid for different intervals. The formation of hydroxy carbonate apatite layer was identified by X-ray diffractometry, scanning electron microscopy (SEM) and energy dispersive spectroscopy. The elastic modulus of the bioactive glasses was measured and found to increase with increasing SrO for SiO2. The blood compatibility of the samples was evaluated. In vitro cell culture studies of the samples were performed using human osteosarcoma U2-OS cell lines and found a significant improvement in cell viability and proliferation. The investigation showed enhancement in bioactivity, mechanical and biological properties of the strontia substituted for silica in glasses. Thus, these bioactive glasses would be highly potential for bone regeneration. Copyright © 2016 Elsevier B.V. All rights reserved.
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Hussain, Sharmila; Tamizhselvi, Ramasamy; George, Leema; Manickam, Venkatraman
2016-01-01
Background and Objectives Morinda citrifolia (Noni), an important traditional medicinal plant still used in patients with bone fractures or dislocation to promote connective tissue repair and to reduce inflammation. However, the effects of Noni on bone metabolism and whether it influences the osteogenic differentiation is yet to be clarified. In this study, we investigated the effect of Morinda citrifolia (Noni) juice on the proliferation rate of rat bone marrow derived mesenchymal stem cells (BMSC) and the osteoblastic differentiation as shown by alkaline phosphatase (ALP), Runt-related transcription factor 2 (Runx2) and osteocalcin (OCN) mRNA expression in vitro. Methods and Results Treatment with 200 μg/ml Noni juice enhanced the proliferation rate of the BMSC and also upregulated the osteogenic differentiation marker genes ALP and OCN, and Runx2 measured by RTPCR. Consistent with these results collagen scaffolds implanted in vivo, which were loaded with BMSC pre-exposed to Noni, showed increased bone density measured by computed tomography and histological analysis revealed neo-angiogenesis for bone formation. Conclusions These results suggest that Noni stimulates osteoblastogenesis and can be used as adjuvant natural medicine for bone diseases such as osteoporosis. PMID:27572713
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Hussain, Sharmila; Tamizhselvi, Ramasamy; George, Leema; Manickam, Venkatraman
2016-11-30
Morinda citrifolia (Noni), an important traditional medicinal plant still used in patients with bone fractures or dislocation to promote connective tissue repair and to reduce inflammation. However, the effects of Noni on bone metabolism and whether it influences the osteogenic differentiation is yet to be clarified. In this study, we investigated the effect of Morinda citrifolia (Noni) juice on the proliferation rate of rat bone marrow derived mesenchymal stem cells (BMSC) and the osteoblastic differentiation as shown by alkaline phosphatase (ALP), Runt-related transcription factor 2 (Runx2) and osteocalcin (OCN) mRNA expression in vitro . Treatment with 200 μg/ml Noni juice enhanced the proliferation rate of the BMSC and also upregulated the osteogenic differentiation marker genes ALP and OCN, and Runx2 measured by RTPCR. Consistent with these results collagen scaffolds implanted in vivo , which were loaded with BMSC pre-exposed to Noni, showed increased bone density measured by computed tomography and histological analysis revealed neo-angiogenesis for bone formation. These results suggest that Noni stimulates osteoblastogenesis and can be used as adjuvant natural medicine for bone diseases such as osteoporosis.
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The Role of Calcium in the Response of Osteoblasts to Mechanical Stimulation
NASA Technical Reports Server (NTRS)
Duncan, R. L.; Farach-Carson, M. C.; Pavalko, F. M.
1999-01-01
A major biomedical concern in the exploration and development of space is the rapid loss of bone associated with extended periods of spaceflight. Mineral content, bone formation, matrix protein production and total body calcium are all reduced during long-term periods of weightlessness. These effects of weightlessness appears to be due to decreases in the anabolic function of osteoblasts and osteocytes rather than changes in the resorptive activity of osteoclasts. Conversely, subjecting the skeleton to exogenous mechanical loading increases matrix protein synthesis and bone formation rate, a process which also appears mediated through osteogenic cells. Osteoblasts have been shown to respond to a number of types of mechanical stimulation. However recently we have demonstrated that osteoblasts respond to fluid shear, but not physiologic levels of mechanical strain, with increases in expression of the matrix protein, osteopontin. We have also shown similar responses in other markers for the anabolic response in bone. The expression of the early response gene, c-fos, and the inducible-isoform of the prostaglandin synthetic enzyme, cyclooygenase-2 (COX-2), both increase rapidly in response to fluid shear, but not strain. How osteoblasts and osteocytes perceive mechanical stimuli and convert this stimulus into a biochemical event within the cell is still unknown. However, examination of the cellular events following mechanical stimulation indicate that two of the earliest responses are a rapid increase in intracellular calcium ([Ca(2+)](sub i)) and a reorganization of the actin cytoskeleton. The increase in [Ca(2+)](sub i) is dependent on the presence of extracellular Ca(2+), suggesting the activation of membrane Ca(2+) channel. We have previously characterized a mechanosensitive, cation-selective channel (MSCC) in osteoblast-like clonal cells, which we postulate is important in this early response to mechanical loading. Using an antisense oligodeoxynucleotide strategy, we have tentatively identified this channel as an isoform of the alc subunit of the dihydropyridine-sensitive, voltage sensitive Ca(2+) channel (VSCC). However, a major component in this mechanically induced rise in [Ca(2+)](sub i) is the release of Ca(2+) from intracellular stores. The actin cytoskeleton also rapidly responds to fluid shear with an increase in stress fiber formation and a realignment of the cell parallel to the direction of flow. To ascertain whether these two observations are related and how they effect shear-induced gene expression, we examined the role of Ca(2+) channels and intracellular Ca(2+) release on cytoskeletal reorganization and the resultant increases in the expression and production of c-fos and COX-2 in response to fluid shear.
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Tissue Engineering Whole Bones Through Endochondral Ossification: Regenerating the Distal Phalanx.
Sheehy, Eamon J; Mesallati, Tariq; Kelly, Lara; Vinardell, Tatiana; Buckley, Conor T; Kelly, Daniel J
2015-01-01
Novel strategies are urgently required to facilitate regeneration of entire bones lost due to trauma or disease. In this study, we present a novel framework for the regeneration of whole bones by tissue engineering anatomically shaped hypertrophic cartilaginous grafts in vitro that subsequently drive endochondral bone formation in vivo. To realize this, we first fabricated molds from digitized images to generate mesenchymal stem cell-laden alginate hydrogels in the shape of different bones (the temporomandibular joint [TMJ] condyle and the distal phalanx). These constructs could be stimulated in vitro to generate anatomically shaped hypertrophic cartilaginous tissues that had begun to calcify around their periphery. Constructs were then formed into the shape of the distal phalanx to create the hypertrophic precursor of the osseous component of an engineered long bone. A layer of cartilage engineered through self-assembly of chondrocytes served as the articular surface of these constructs. Following chondrogenic priming and subcutaneous implantation, the hypertrophic phase of the engineered phalanx underwent endochondral ossification, leading to the generation of a vascularized bone integrated with a covering layer of stable articular cartilage. Furthermore, spatial bone deposition within the construct could be modulated by altering the architecture of the osseous component before implantation. These findings open up new horizons to whole limb regeneration by recapitulating key aspects of normal bone development.
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Tissue engineering skeletal muscle for orthopaedic applications
NASA Technical Reports Server (NTRS)
Payumo, Francis C.; Kim, Hyun D.; Sherling, Michael A.; Smith, Lee P.; Powell, Courtney; Wang, Xiao; Keeping, Hugh S.; Valentini, Robert F.; Vandenburgh, Herman H.
2002-01-01
With current technology, tissue-engineered skeletal muscle analogues (bioartificial muscles) generate too little active force to be clinically useful in orthopaedic applications. They have been engineered genetically with numerous transgenes (growth hormone, insulinlike growth factor-1, erythropoietin, vascular endothelial growth factor), and have been shown to deliver these therapeutic proteins either locally or systemically for months in vivo. Bone morphogenetic proteins belonging to the transforming growth factor-beta superfamily are osteoinductive molecules that drive the differentiation pathway of mesenchymal cells toward the chondroblastic or osteoblastic lineage, and stimulate bone formation in vivo. To determine whether skeletal muscle cells endogenously expressing bone morphogenetic proteins might serve as a vehicle for systemic bone morphogenetic protein delivery in vivo, proliferating skeletal myoblasts (C2C12) were transduced with a replication defective retrovirus containing the gene for recombinant human bone morphogenetic protein-6 (C2BMP-6). The C2BMP-6 cells constitutively expressed recombinant human bone morphogenetic protein-6 and synthesized bioactive recombinant human bone morphogenetic protein-6, based on increased alkaline phosphatase activity in coincubated mesenchymal cells. C2BMP-6 cells did not secrete soluble, bioactive recombinant human bone morphogenetic protein-6, but retained the bioactivity in the cell layer. Therefore, genetically-engineered skeletal muscle cells might serve as a platform for long-term delivery of osteoinductive bone morphogenetic proteins locally.
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Misiorowski, Waldemar
2011-01-01
Most medical agents currently applied in osteoporosis therapy act by inhibiting bone resorption and reducing bone remodelling, i.e. they inhibit the process of bone mass loss by suppressing bone resorption processes. These drugs provide an ideal therapeutic option to prevent osteoporosis progression. They however have a rather limited usefulness when the disease has already reached its advanced stages with distinctive bone architecture lesions. The fracture risk reduction rate, achieved in the course of anti-resorptive therapy, is insufficient for patients with severe osteoporosis to stop the downward spiral of their quality of life (QoL) with a simultaneously increasing threat of premature death. The activity of the N-terminal fragment of 1-34 human parathormone (teriparatide - 1-34 rhPTH), a parathyroid hormone (PTH) analogue obtained via genetic engineering , is expressed by increased bone metabolism, while promoting new bone tissue formation by stimulating the activity of osteoblasts more than that of osteoclasts. The anabolic activity of PTH includes both its direct effect on the osteoblast cell line, and its indirect actions exerted via its regulatory effects on selected growth factors, e.g. IGF-1 or sclerostin. However, the molecular mechanisms responsible for the actual anabolic effects of PTH remain mostly still unclear. Clinical studies have demonstrated that therapeutic protocols with the application of PTH analogues provide an effective protection against all osteoporotic fracture types in post-menopausal women and in elderly men with advanced osteoporosis. Particular hopes are pinned on the possibility of applying PTH in the therapy of post-steroid osteoporosis, mainly to suppress bone formation, the most important pathological process in this regard. The relatively short therapy period with a PTH analogue (24 months) should then be replaced and continued by anti-resorptive treatment.
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Misiorowski, Waldemar
2011-01-01
Most medical agents currently applied in osteoporosis therapy act by inhibiting bone resorption and reducing bone remodelling, i.e. they inhibit the process of bone mass loss by suppressing bone resorption processes. These drugs provide an ideal therapeutic option to prevent osteoporosis progression. They however have a rather limited usefulness when the disease has already reached its advanced stages with distinctive bone architecture lesions. The fracture risk reduction rate, achieved in the course of anti-resorptive therapy, is insufficient for patients with severe osteoporosis to stop the downward spiral of their quality of life (QoL) with a simultaneously increasing threat of premature death. The activity of the N-terminal fragment of 1-34 human parathormone (teriparatide - 1-34 rhPTH), a parathyroid hormone (PTH) analogue obtained via genetic engineering , is expressed by increased bone metabolism, while promoting new bone tissue formation by stimulating the activity of osteoblasts more than that of osteoclasts. The anabolic activity of PTH includes both its direct effect on the osteoblast cell line, and its indirect actions exerted via its regulatory effects on selected growth factors, e.g. IGF-1 or sclerostin. However, the molecular mechanisms responsible for the actual anabolic effects of PTH remain mostly still unclear. Clinical studies have demonstrated that therapeutic protocols with the application of PTH analogues provide an effective protection against all osteoporotic fracture types in post-menopausal women and in elderly men with advanced osteoporosis. Particular hopes are pinned on the possibility of applying PTH in the therapy of post-steroid osteoporosis, mainly to suppress bone formation, the most important pathological process in this regard. The relatively short therapy period with a PTH analogue (24 months) should then be replaced and continued by anti-resorptive treatment.
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The molecular response of bone to growth hormone during skeletal unloading: regional differences
NASA Technical Reports Server (NTRS)
Bikle, D. D.; Harris, J.; Halloran, B. P.; Currier, P. A.; Tanner, S.; Morey-Holton, E.
1995-01-01
Hind limb elevation of the growing rat provides a good model for the skeletal changes that occur during space flight. In this model the bones of the forelimbs (normally loaded) are used as an internal control for the changes that occur in the unloaded bones of the hind limbs. Previous studies have shown that skeletal unloading of the hind limbs results in a transient reduction of bone formation in the tibia and femur, with no change in the humerus. This fall in bone formation is accompanied by a fall in serum osteocalcin (bone Gla protein, BGP) and bone BGP messenger RNA (mRNA) levels, but a rise in bone insulin-like growth factor-I (IGF-I) protein and mRNA levels and resistance to the skeletal growth-promoting actions of IGF-I. To determine whether skeletal unloading also induced resistance to GH, we evaluated the response of the femur and humerus of sham and hypophysectomized rats, control and hind limb elevated, to GH (two doses), measuring mRNA levels of IGF-I, BGP, rat bone alkaline phosphatase (RAP), and alpha 1(1)-procollagen (coll). Hypophysectomy (HPX) decreased the mRNA levels of IGF-I, BGP, and coll in the femur, but was either less effective or had the opposite effect in the humerus. GH at the higher dose (500 micrograms/day) restored these mRNA levels to or above the sham control values in the femur, but generally had little or no effect on the humerus. RAP mRNA levels were increased by HPX, especially in the femur. The lower dose of GH (50 micrograms/day) inhibited this rise in RAP, whereas the higher dose raised the mRNA levels and resulted in the appearance of additional transcripts not seen in controls. As for the other mRNAs, RAP mRNA in the humerus was less affected by HPX or GH than that in the femur. Hind limb elevation led to an increase in IGF-I, coll, and RAP mRNAs and a reduction in BGP mRNA in the femur and either had no effect or potentiated the response of these mRNAs to GH. We conclude that GH stimulates a number of markers of bone formation by raising their mRNA levels, and that skeletal unloading does not block this response, but the response varies substantially from bone to bone.
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Bagi, Cedo M; Berryman, Edwin; Zakur, David E; Wilkie, Dean; Andresen, Catharine J
2015-11-06
Osteoarthritis (OA) is a leading cause of disability, but despite the high unmet clinical need and extensive research seeking dependable therapeutic interventions, no proven disease-modifying treatment for OA is currently available. Due to the close interaction and interplay between the articular cartilage and the subchondral bone plate, it has been hypothesized that antiresorptive drugs can also reduce cartilage degradation, inhibit excessive turnover of the subchondral bone plate, prevent osteophyte formation, and/or that bone anabolic drugs might also stimulate cartilage synthesis by chondrocytes and preserve cartilage integrity. The benefit of intensive zoledronate (Zol) and parathyroid hormone (PTH) therapy for bone and cartilage metabolism was evaluated in a rat model of OA. Medial meniscectomy (MM) was used to induce OA in male Lewis rats. Therapy with Zol and human PTH was initiated immediately after surgery. A dynamic weight-bearing (DWB) system was deployed to evaluate the weight-bearing capacity of the front and hind legs. At the end of the 10-week study, the rats were euthanized and the cartilage pathology was evaluated by contrast (Hexabrix)-enhanced μCT imaging and traditional histology. Bone tissue was evaluated at the tibial metaphysis and epiphysis, including the subchondral bone. Histological techniques and dynamic histomorphometry were used to evaluate cartilage morphology and bone mineralization. The results of this study highlight the complex changes in bone metabolism in different bone compartments influenced by local factors, including inflammation, pain and mechanical loads. Surgery caused severe and extensive deterioration of the articular cartilage at the medial tibial plateau, as evidenced by contrast-enhanced μCT and histology. The study results showed the negative impact of MM surgery on the weight-bearing capacity of the operated limb, which was not corrected by treatment. Although both Zol and PTH improved subchondral bone mass and Zol reduced serum CTX-II level, both treatments failed to prevent or correct cartilage deterioration, osteophyte formation and mechanical incapacity. The various methods utilized in this study showed that aggressive treatment with Zol and PTH did not have the capacity to prevent or correct the deterioration of the hyaline cartilage, thickening of the subchondral bone plate, osteophyte formation or the mechanical incapacity of the osteoarthritic knee.
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MiR-214 regulates the function of osteoblast under simulated microgravity by targeting ATF4
NASA Astrophysics Data System (ADS)
Li, Yingxian; Wang, Xiaogang; Li, Qi; Lv, Ke; Wan, Yumin; Li, Yinghui; Bai, Yanqiang
Background: MicroRNAs (miRNAs) are small fragments of single-stranded RNA containing 18-24 nucleotides, and are generated from endogenous transcripts. MicroRNAs function in post-transcriptional gene silencing by targeting the 3'-untranslated region (UTR) of mRNAs, resulting in translational repression. Growing evidence shows that microRNAs (miRNAs) regu-late various developmental and homeostatic events in vertebrates and invertebrates. Osteoblast differentiation is a key step in proper skeletal development and acquisition of bone mass; How-ever, the physiological role of non-coding small RNAs, especially miRNAs, in osteoblast dif-ferentiation remains elusive. Methods: To study the potential involvement of miRNAs in osteoblast differentiation under stimulated microgravity, we analyzed the expression of 20 bone relative miRNAs using real time PCR platform to find particularly miRNAs whose expression is altered during osteoblast differentiation. TargetScan, miRBase and Miranda were used to predict the target gene of candidate miRNA. To investigate whether ATF4 can be directly targeted by miR-214, we engineered luciferase reporters that have either the wild-type 3'UTRs of these genes, or the mutant UTRs with a 6 base pair (bp) deletion in the target sites. Lastly, to address the in vivo role of miR-214 in bone formation, tail suspension mice model was used to simulate the change of osteoblast function and bone loss. Results: Recent studies have sug-gested that miRNAs might play a role in osteoblast differentiation and bone formation. Here, we identify miR-214 in MC3T3-E1 cells, which is a primary mouse osteoblasts cell line, to promote osteoblast differentiation by repressing Activating Transcription Factor4 (ATF4) ex-pression at the posttranscriptional level. What is more, miR-214 was found to be transcribed in C2C12 cells during bone morphogenetic protein 2-induced (BMP2-induced) osteogenesis, and overexpression of miR-214 attenuated BMP2-induced osteoblastogenesis, whereas inhibition of miR-214 expression enhanced this progress. The levels of miR-214 increased dramatically in tail suspension mice. Conclusions: Thus, our studies show that miR-214 plays an important role in osteoblast differentiation by targeting ATF4 under stimulated microgravity induced bone loss and contributes to osteoporosis via its effect on osteoblasts.
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Sharmin, Farzana; McDermott, Casey; Lieberman, Jay; Sanjay, Archana; Khan, Yusuf
2017-05-01
Autografts have been shown to stimulate osteogenesis, osteoclastogenesis, and angiogenesis, and subsequent rapid graft incorporation. Large structural allografts, however, suffer from limited new bone formation and remodeling, both of which are directly associated with clinical failure due to non-unions, late graft fractures, and infections, making it a priority to improve large structural allograft healing. We have previously shown the osteogenic ability of a polymer-coated allograft that delivers bone morphogenetic protein-2 both in vitro and in vivo through both burst release and sustained release kinetics. In this study, we have demonstrated largely sequential delivery of bone morphogenetic protein-2 and vascular endothelial growth factor from the same coated allograft. Release data showed that loading both growth factors onto a polymeric coating with two different techniques resulted in short-term (95% release within 2 weeks) and long-term (95% release within 5 weeks) delivery kinetics. We have also demonstrated how released VEGF, traditionally associated with angiogenesis, can also provide a stimulus for allograft remodeling via resorption. Bone marrow derived mononuclear cells were co-cultured with VEGF released from the coated allograft and showed a statistically significant (p < 0.05) and dose dependent increase in the number of tartrate-resistant acid phosphatase-positive multinucleated osteoclasts. Functionality of these osteoclasts was assessed quantitatively and qualitatively by evaluating resorption pit area from both osteo-assay plates and harvested bone. Data indicated a statistically significant higher resorption area from the cells exposed to VEGF released from the allografts over controls (p < 0.05). These results indicate that by using different loading protocols temporal control can be achieved when delivering multiple growth factors from a polymer-coated allograft. Further, released VEGF can also stimulate osteoclastogenesis that may enhance allograft incorporation, and thus mitigate long-term clinical complications. © 2017 Orthopedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1086-1095, 2017. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.
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Testosterone Combined with Electrical Stimulation and Standing: Effect on Muscle and Bone
2016-10-01
AWARD NUMBER: W81XWH-14-2-0190 TITLE: Testosterone Combined with Electrical Stimulation and Standing: Effect on Muscle and Bone PRINCIPAL...including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and...2015 - 29 Sep 2016 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Testosterone Combined with Electrical Stimulation and Standing: Effect on Muscle and Bone
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Laser Sintered Porous Ti-6Al-4V Implants Stimulate Vertical Bone Growth.
Cheng, Alice; Cohen, David J; Kahn, Adrian; Clohessy, Ryan M; Sahingur, Kaan; Newton, Joseph B; Hyzy, Sharon L; Boyan, Barbara D; Schwartz, Zvi
2017-08-01
The objective of this study was to examine the ability of 3D implants with trabecular-bone-inspired porosity and micro-/nano-rough surfaces to enhance vertical bone ingrowth. Porous Ti-6Al-4V constructs were fabricated via laser-sintering and processed to obtain micro-/nano-rough surfaces. Male and female human osteoblasts were seeded on constructs to analyze cell morphology and response. Implants were then placed on rat calvaria for 10 weeks to assess vertical bone ingrowth, mechanical stability and osseointegration. All osteoblasts showed higher levels of osteocalcin, osteoprotegerin, vascular endothelial growth factor and bone morphogenetic protein 2 on porous constructs compared to solid laser-sintered controls. Porous implants placed in vivo resulted in an average of 3.1 ± 0.6 mm 3 vertical bone growth and osseointegration within implant pores and had significantly higher pull-out strength values than solid implants. New bone formation and pull-out strength was not improved with the addition of demineralized bone matrix putty. Scanning electron images and histological results corroborated vertical bone growth. This study indicates that Ti-6Al-4V implants fabricated by additive manufacturing to have porosity based on trabecular bone and post-build processing to have micro-/nano-surface roughness can support vertical bone growth in vivo, and suggests that these implants may be used clinically to increase osseointegration in challenging patient cases.
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Qi, Xin; Liu, Yang; Ding, Zhen-yu; Cao, Jia-qing; Huang, Jing-huan; Zhang, Jie-yuan; Jia, Wei-tao; Wang, Jing; Liu, Chang-sheng; Li, Xiao-lin
2017-01-01
In bone remodeling, osteogenesis is closely coupled to angiogenesis. Bone tissue engineering using multifunctional bioactive materials is a promising technique which has the ability to simultaneously stimulate osteogenesis and angiogenesis for repair of bone defects. We developed mesoporous bioactive glass (MBG)-doped poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) composite scaffolds as delivery vehicle. Two bioactive molecules, dimethyloxalylglycine (DMOG), a small-molecule angiogenic drug, and recombinant human bone morphogenetic protein-2 (rhBMP-2), an osteoinductive growth factor, were co-incorporated into the scaffold. The synergistic effects of DMOG and rhBMP-2 released in the composite scaffolds on osteogenic and angiogenic differentiation of hBMSCs were investigated using real-time quantitative polymerase chain reaction and western blotting. Moreover, in vivo studies were conducted to observe bone regeneration and vascular formation of critical-sized bone defects in rats using micro-computed tomography, histological analyses, Microfil® perfusion, fluorescence labeling, and immunohistochemical analysis. The results showed that DMOG and rhBMP-2 released in the MBG-PHBHHx scaffolds did exert synergistic effects on the osteogenic and angiogenic differentiation of hBMSCs. Moreover, DMOG and rhBMP-2 produced significant increases in newly-formed bone and neovascularization of calvarial bone defects in rats. It is concluded that the co-delivery strategy of both rhBMP-2 and DMOG can significantly improve the critical-sized bone regeneration. PMID:28230059
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A crucial role for thiol antioxidants in estrogen-deficiency bone loss
Lean, Jenny M.; Davies, Julie T.; Fuller, Karen; Jagger, Christopher J.; Kirstein, Barrie; Partington, Geoffrey A.; Urry, Zoë L.; Chambers, Timothy J.
2003-01-01
The mechanisms through which estrogen prevents bone loss are uncertain. Elsewhere, estrogen exerts beneficial actions by suppression of reactive oxygen species (ROS). ROS stimulate osteoclasts, the cells that resorb bone. Thus, estrogen might prevent bone loss by enhancing oxidant defenses in bone. We found that glutathione and thioredoxin, the major thiol antioxidants, and glutathione and thioredoxin reductases, the enzymes responsible for maintaining them in a reduced state, fell substantially in rodent bone marrow after ovariectomy and were rapidly normalized by exogenous 17-β estradiol. Moreover, administration of N-acetyl cysteine (NAC) or ascorbate, antioxidants that increase tissue glutathione levels, abolished ovariectomy-induced bone loss, while L-buthionine-(S,R)-sulphoximine (BSO), a specific inhibitor of glutathione synthesis, caused substantial bone loss. The 17-β estradiol increased glutathione and glutathione and thioredoxin reductases in osteoclast-like cells in vitro. Furthermore, in vitro NAC prevented osteoclast formation and NF-κB activation. BSO and hydrogen peroxide did the opposite. Expression of TNF-α, a target for NF-κB and a cytokine strongly implicated in estrogen-deficiency bone loss, was suppressed in osteoclasts by 17-β estradiol and NAC. These observations strongly suggest that estrogen deficiency causes bone loss by lowering thiol antioxidants in osteoclasts. This directly sensitizes osteoclasts to osteoclastogenic signals and entrains ROS-enhanced expression of cytokines that promote osteoclastic bone resorption. PMID:12975476
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NASA Astrophysics Data System (ADS)
Qi, Xin; Liu, Yang; Ding, Zhen-Yu; Cao, Jia-Qing; Huang, Jing-Huan; Zhang, Jie-Yuan; Jia, Wei-Tao; Wang, Jing; Liu, Chang-Sheng; Li, Xiao-Lin
2017-02-01
In bone remodeling, osteogenesis is closely coupled to angiogenesis. Bone tissue engineering using multifunctional bioactive materials is a promising technique which has the ability to simultaneously stimulate osteogenesis and angiogenesis for repair of bone defects. We developed mesoporous bioactive glass (MBG)-doped poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) composite scaffolds as delivery vehicle. Two bioactive molecules, dimethyloxalylglycine (DMOG), a small-molecule angiogenic drug, and recombinant human bone morphogenetic protein-2 (rhBMP-2), an osteoinductive growth factor, were co-incorporated into the scaffold. The synergistic effects of DMOG and rhBMP-2 released in the composite scaffolds on osteogenic and angiogenic differentiation of hBMSCs were investigated using real-time quantitative polymerase chain reaction and western blotting. Moreover, in vivo studies were conducted to observe bone regeneration and vascular formation of critical-sized bone defects in rats using micro-computed tomography, histological analyses, Microfil® perfusion, fluorescence labeling, and immunohistochemical analysis. The results showed that DMOG and rhBMP-2 released in the MBG-PHBHHx scaffolds did exert synergistic effects on the osteogenic and angiogenic differentiation of hBMSCs. Moreover, DMOG and rhBMP-2 produced significant increases in newly-formed bone and neovascularization of calvarial bone defects in rats. It is concluded that the co-delivery strategy of both rhBMP-2 and DMOG can significantly improve the critical-sized bone regeneration.
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The soleus syndrome. A cause of medial tibial stress (shin splints).
Michael, R H; Holder, L E
1985-01-01
Radionuclide bone scans have demonstrated linear uptake along the posterior medial border of the tibia in patients with shin splints. This area was investigated by anatomical dissection (14 human cadavers), electromyographic (EMG) and muscle stimulation studies (10 patients), and open biopsy (1 patient). Histologically, the increased metabolic activity manifested on the radionuclide scan is due to a periostitis with new bone formation. The soleus muscle and its investing fascia are anatomically and biomechanically implicated in the production of these stress changes, particularly when the heel is in the pronated position. The soleus muscle and fascia form a tough "soleus bridge" over the deep compartment which is thought to be important in patients requiring surgical decompression.
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Du, Erxia; McAllister, Patrick; Venna, Venugopal Reddy; Xiao, Liping
2017-04-01
Ketamine has been used safely in clinics for decades for analgesia and anesthesia. It is increasingly popular in clinical practice due to its new uses and importance for emergency procedures. It is known that ketamine is sequestered in the bone marrow and the major receptors for ketamine, noncompetitive N-methyl-d-aspartate receptors (NMDARs), are expressed in osteoclasts (OCs) and osteoblasts. However, the impact of ketamine on OCs or osteoblasts is unknown. In this study, we investigated the effects of ketamine on osteoclastogenesis and regulation of NMDARs expression in vitro. Bone marrows (BMs) or bone marrow macrophages (BMMs) were cultured in the presence of macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor kappa-B ligand (RANKL) with or without ketamine for up to 6 days. OC formation peaked at day 5. On day 5 of culture, ketamine inhibited OC formation from both BM and BMM cultures at clinically relevant concentrations (3-200 µM). Ketamine inhibited RANKL-induced expression of nuclear factor of activated T-cells, cytoplasmic, calcineurin-dependent 1 (NFATc1) in BMM cultures. Inhibition of ketamine on RANKL-induced osteoclastogenesis is associated with down-regulation of NMDARs. In addition, ketamine significantly inhibited the M-CSF induced migration of BMMs, inhibited cell fusion and significantly increased mature OC apoptosis. We conclude that clinically relevant concentrations of ketamine inhibit OC formation in both BM and BMM cultures in vitro through inhibiting migration and fusion process and enhancing mature OC apoptosis. It is likely that ketamine regulates osteoclastogenesis, at least in part, via its effects on NMDAR expression. J. Cell. Biochem. 118: 914-923, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.
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Bechtold, Till E.; Saunders, Cheri; Decker, Rebekah S.; Um, Hyo-Bin; Cottingham, Naiga; Salhab, Imad; Kurio, Naito; Billings, Paul C.; Pacifici, Maurizio; Nah, Hyun-Duck; Koyama, Eiki
2016-01-01
The temporomandibular joint (TMJ) is a diarthrodial joint that relies on lubricants for frictionless movement and long-term function. It remains unclear what temporal and causal relationships may exist between compromised lubrication and onset and progression of TMJ disease. Here we report that Proteoglycan 4 (Prg4)-null TMJs exhibit irreversible osteoarthritis-like changes over time and are linked to formation of ectopic mineralized tissues and osteophytes in articular disc, mandibular condyle and glenoid fossa. In the presumptive layer of mutant glenoid fossa’s articulating surface, numerous chondrogenic cells and/or chondrocytes emerged ectopically within the type I collagen-expressing cell population, underwent endochondral bone formation accompanied by enhanced Ihh expression, became entrapped into temporal bone mineralized matrix, and thereby elicited excessive chondroid bone formation. As the osteophytes grew, the roof of the glenoid fossa/eminence became significantly thicker and flatter, resulting in loss of its characteristic concave shape for accommodation of condyle and disc. Concurrently, the condyles became flatter and larger and exhibited ectopic bone along their neck, likely supporting the enlarged condylar heads. Articular discs lost their concave configuration, and ectopic cartilage developed and articulated with osteophytes. In glenoid fossa cells in culture, hedgehog signaling stimulated chondrocyte maturation and mineralization including alkaline phosphatase, while treatment with hedgehog inhibitor HhAntag prevented such maturation process. In sum, our data indicate that Prg4 is needed for TMJ integrity and long-term postnatal function. In its absence, progenitor cells near presumptive articular layer and disc undergo ectopic chondrogenesis and generate ectopic cartilage, possibly driven by aberrant activation of Hh signaling. The data suggest also that the Prg4-null mice represent a useful model to study TMJ osteoarthritis-like degeneration and clarify its pathogenesis. PMID:26945615
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Influence of physical activity on tibial bone material properties in laying hens
DOE Office of Scientific and Technical Information (OSTI.GOV)
Rodriguez-Navarro, A. B.; McCormack, H. M.; Fleming, R. H.
Laying hens develop a type of osteoporosis that arises from a loss of structural bone, resulting in high incidence of fractures. In this study, a comparison of bone material properties was made for lines of hens created by divergent selection to have high and low bone strength and housed in either individual cages, with restricted mobility, or in an aviary system, with opportunity for increased mobility. Improvement of bone biomechanics in the high line hens and in aviary housing was mainly due to increased bone mass, thicker cortical bone and more medullary bone. However, bone material properties such as corticalmore » and medullary bone mineral composition and crystallinity as well as collagen maturity did not differ between lines. However, bone material properties of birds from the different type of housing were markedly different. The cortical bone in aviary birds had a lower degree of mineralization and bone mineral was less mature and less organized than in caged birds. Here, these differences can be explained by increased bone turnover rates due to the higher physical activity of aviary birds that stimulates bone formation and bone remodeling. Multivariate statistical analyses shows that both cortical and medullary bone contribute to breaking strengthThe cortical thickness was the single most important contributor while its degree of mineralization and porosity had a smaller contribution. Lastly, bone properties had poorer correlations with mechanical properties in cage birds than in aviary birds presumably due to the greater number of structural defects of cortical bone in cage birds.« less
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Influence of physical activity on tibial bone material properties in laying hens
Rodriguez-Navarro, A. B.; McCormack, H. M.; Fleming, R. H.; ...
2017-11-03
Laying hens develop a type of osteoporosis that arises from a loss of structural bone, resulting in high incidence of fractures. In this study, a comparison of bone material properties was made for lines of hens created by divergent selection to have high and low bone strength and housed in either individual cages, with restricted mobility, or in an aviary system, with opportunity for increased mobility. Improvement of bone biomechanics in the high line hens and in aviary housing was mainly due to increased bone mass, thicker cortical bone and more medullary bone. However, bone material properties such as corticalmore » and medullary bone mineral composition and crystallinity as well as collagen maturity did not differ between lines. However, bone material properties of birds from the different type of housing were markedly different. The cortical bone in aviary birds had a lower degree of mineralization and bone mineral was less mature and less organized than in caged birds. Here, these differences can be explained by increased bone turnover rates due to the higher physical activity of aviary birds that stimulates bone formation and bone remodeling. Multivariate statistical analyses shows that both cortical and medullary bone contribute to breaking strengthThe cortical thickness was the single most important contributor while its degree of mineralization and porosity had a smaller contribution. Lastly, bone properties had poorer correlations with mechanical properties in cage birds than in aviary birds presumably due to the greater number of structural defects of cortical bone in cage birds.« less
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Gislason, Magnus K; Ingvarsson, Páll; Gargiulo, Paolo; Yngvason, Stefán; Guðmundsdóttir, Vilborg; Knútsdóttir, Sigrún; Helgason, Þórður
2014-09-23
Bone loss and a decrease in bone mineral density is frequently seen in patients with motor neuron lesion due to lack of mechanical stimulation. This causes weakening of the bones and a greater risk of fracture. By using functional electrical stimulation it is possible to activate muscles in the body to produce the necessary muscle force to stimulate muscle growth and potentially decrease the rate of bone loss. A longitudinal study was carried out on a single patient undergoing electrical stimulation over a 6 year period. The patient underwent a CT scan each year and a full three dimensional finite element model for each year was created using Mimics (Materialise) and Abaqus (Simulia) to calculate the risk of fracture under physiologically relevant loading conditions. Using empirical formulas connecting the bone mineral density to the stiffness and ultimate tensile stress of the bone, each element was assigned a unique material property, based on its density. The risk of fracture was estimated by calculating the ratio between the predicted stress and the ultimate tensile stress, should it exceed unity, failure was assumed. The results showed that the number of elements that were predicted to be at risk of failure varied between years.
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Pang, Wai-Yin; Wang, Xin-Lun; Mok, Sau-Keng; Lai, Wan-Ping; Chow, Hung-Kay; Leung, Ping-Chung; Yao, Xin-Sheng; Wong, Man-Sau
2010-01-01
Background and purpose: Naringin, a flavanone glycoside in citrus fruits, has been recently reported to stimulate bone formation in vitro and in vivo. The present study was designed to determine if naringin could exert oestrogen-like protective actions in bone. Experimental approach: Young C57/BL6J mice were ovariectomized (OVX) and treated orally with naringin (0.2 or 0.4 mg·g−1·day−1), 17β-oestradiol (2 µg·g−1·day−1) or its vehicle for 6 weeks. Bone mineral densities (BMD) and polar stress-strain index (SSI) were measured by peripheral quantitative computed tomography. Rat osteoblast-like UMR-106 cells were co-incubated with the oestrogen receptor (ER) antagonist ICI 182780 to determine if the effects of naringin on osteoblastic functions were ER dependent. Functional transactivation of ERα and ERβ as well as ERα phosphorylation by naringin were also studied. Key results: Naringin at 0.4 mg·g−1·day−1 increased BMD at trabecular-rich bone in OVX mice. Naringin (at both doses) significantly increased SSI at distal femur and lumbar spine and increased biomechanical strength (ultimate load and energy for breaking) at tibia diaphysis in OVX mice. The stimulatory effects of naringin on osteoblastic functions could be abolished by co-incubation with ICI 182780 in UMR-106 cells. Naringin failed to stimulate ERα- or ERβ-mediated oestrogen response element-dependent luciferase activity but could significantly induce ERα phosphorylation at serine 118, in UMR-106 cells. Conclusions and implications: Naringin was effective in protecting against OVX-induced bone loss in mice and its actions might be mediated through ligand-independent activation of ER in osteoblastic cells. PMID:20397301
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Emerging paradigms and questions on pro-angiogenic bone marrow-derived myelomonocytic cells.
Laurent, Julien; Touvrey, Cédric; Botta, Francesca; Kuonen, François; Ruegg, Curzio
2011-01-01
Cancer-related inflammation has emerged in recent years as a major event contributing to tumor angiogenesis, tumor progression and metastasis formation. Bone marrow-derived and inflammatory cells promote tumor angiogenesis by providing endothelial progenitor cells that differentiate into mature endothelial cells, and by secreting pro-angiogenic factors and remodeling the extracellular matrix to stimulate angiogenesis though paracrine mechanisms. Several bone marrow-derived myelonomocytic cells, including monocytes and macrophages, have been identified and characterized by several laboratories in recent years. While the central role of these cells in promoting tumor angiogenesis, tumor progression and metastasis is nowadays well established, many questions remain open and new ones are emerging. These include the relationship between their phenotype and function, the mechanisms of pro-angiogenic programming, their contribution to resistance to anti-angiogenic treatments and to metastasis and their potential clinical use as biomarkers of angiogenesis and anti-angiogenic therapies. Here, we will review phenotypical and functional aspects of bone marrow-derived myelonomocytic cells and discuss some of the current outstanding questions.
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Uskoković, Vuk; Desai, Tejal A.
2014-01-01
S aureus internalized by bone cells and shielded from the immune system provides a reservoir of bacteria in recurring osteomyelitis. Its targeting by the antibiotic therapy may thus be more relevant for treating chronic bone infection than eliminating only the pathogens colonizing the bone matrix. Assessed was the combined osteogenic and antibacterial effect of clindamycin-loaded calcium phosphate nanoparticles of different monophasic compositions on co-cultures comprising osteoblasts infected with S aureus. Antibiotic-carrying particles were internalized by osteoblasts and minimized the concentration of intracellular bacteria. In vitro treatments of the infected cells, however, could not prevent cell necrosis due to the formation of toxic byproducts of the degradation of the bacterium. Antibiotic-loaded particles had a positive morphological effect on osteoblasts per se, without reducing their viability, alongside stimulating upregulation of expression of different bone growth markers in infected osteoblasts to a higher degree than achieved during the treatment with antibiotic only. PMID:24582242
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Properties of the "Orgamax" osteoplastic material made of a demineralized allograft bone
NASA Astrophysics Data System (ADS)
Podorognaya, V. T.; Kirilova, I. A.; Sharkeev, Yu. P.; Uvarkin, P. V.; Zhelezny, P. A.; Zheleznaya, A. P.; Akimova, S. E.; Novoselov, V. P.; Tupikova, L. N.
2016-08-01
We investigated properties of the "Orgamax" osteoplastic material, which was produced from a demineralized bone, in the treatment of extensive caries, in particular chronic pulpitis of the permanent teeth with unformed roots in children. The "Orgamax" osteoplastic material consists of demineralized bone chips, a collagen additive, and antibiotics. The surface morphology of the "Orgamax" osteoplastic material is macroporous, with the maximum pore size of 250 µm, whereas the surface morphology of the major component of "Orgamax", demineralized bone chips, is microporous, with a pore size of 10-20 µm. Material "Orgamax" is used in the treatment of complicated caries, particularly chronic pulpitis of permanent teeth with unformed roots in children. "Orgamax" filling a formed cavity exhibits antimicrobial properties, eliminates inflammation in the dental pulp, and, due to its osteoconductive and osteoinductive properties, undergoes gradual resorption, stimulates regeneration, and provides replacement of the defect with newly formed tissue. The dental pulp viability is completely restored, which ensures the complete formation of tooth roots with root apex closure in the long-term period.
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Dual Role of Cyanidin-3-glucoside on the Differentiation of Bone Cells.
Park, K H; Gu, D R; So, H S; Kim, K J; Lee, S H
2015-12-01
Cyanidin-3-glucoside (C3G) is one of the major components of anthocyanin, a water-soluble phytochemical. Recent studies demonstrated the chemopreventive and chemotherapeutic activities of C3G in various conditions, including cancer, although the precise effects of C3G on osteoclast and osteoblast differentiation remain unclear. Here, we investigated the role of C3G in the differentiation of bone-associated cells and its underlying mechanism. C3G inhibited receptor activator of nuclear factor kappa-B ligand (RANKL)-mediated osteoclast differentiation and formation in a dose-dependent manner and downregulated the expression of osteoclast differentiation marker genes. Pretreatment with C3G considerably reduced the induction of extracellular signal-regulated kinase, c-Jun N-terminal kinase, and p38 mitogen-activated kinases activation by RANKL in osteoclast precursor cells. Furthermore, C3G dramatically inhibited the expression of c-Fos and nuclear factor of activated T-cells, cytoplasmic 1, which are important transcription factors for osteoclast differentiation and activation. The formation of osteoclasts in coculture of bone marrow cells and calvaria-derived osteoblasts was also inhibited by C3G treatment, although the expression of macrophage colony-stimulating factor and RANKL (master factors for osteoclast differentiation and formation) and osteoprotegerin (a decoy receptor for RANKL) on osteoblasts was unaffected. The inhibitory effect of C3G on osteoclastogenesis is therefore targeted specifically to osteoclasts but not osteoblasts. Moreover, analysis of the expression levels of osteoblast differentiation marker genes and alizarin red staining showed that osteoblast differentiation and matrix formation increased after C3G treatment. Taken together, these results strongly suggest that C3G has a dual role in bone metabolism, as an effective inhibitor of osteoclast differentiation but also as an activator of osteoblast differentiation. Therefore, C3G may be used as a potent preventive or therapeutic agent for bone-related diseases, such as osteoporosis, rheumatoid arthritis, and periodontitis. © International & American Associations for Dental Research 2015.
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Anabolic Therapy for the Treatment of Osteoporosis in Childhood.
Ward, Leanne M; Rauch, Frank
2018-06-01
Numerous forms of osteoporosis in childhood are characterized by low bone turnover (for example, osteoporosis due to neuromuscular disorders and glucocorticoid exposure). Anti-resorptive therapy, traditionally used to treat osteoporosis in the young, is associated with further reductions in bone turnover, raising concerns about the long-term safety and efficacy of such therapy. These observations have led to increasing interest in the role of anabolic therapy to treat pediatric osteoporosis. While growth hormone and androgens appears to be relatively weak anabolic modulators of bone mass, emerging therapies targeting bone formation pathways (anti-transforming growth factor beta antibody and anti-sclerostin antibody) hold considerable promise. Teriparatide remains an attractive option that merits formal study for patients post-epiphyseal fusion, although it must be considered that adult studies have shown its effect is blunted when administered following bisphosphonate therapy. Mechanical stimulation of bone through whole body vibration therapy appears to be much less effective than bisphosphonate therapy for treating osteoporosis in children. New anabolic therapies which target important pathways in skeletal metabolism merit further study in children, including their effects on fracture risk reduction and after treatment discontinuation.
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Bolander, Johanna; Ji, Wei; Leijten, Jeroen; Teixeira, Liliana Moreira; Bloemen, Veerle; Lambrechts, Dennis; Chaklader, Malay; Luyten, Frank P
2017-03-14
Clinical translation of cell-based strategies for regenerative medicine demands predictable in vivo performance where the use of sera during in vitro preparation inherently limits the efficacy and reproducibility. Here, we present a bioinspired approach by serum-free pre-conditioning of human periosteum-derived cells, followed by their assembly into microaggregates simultaneously primed with bone morphogenetic protein 2 (BMP-2). Pre-conditioning resulted in a more potent progenitor cell population, while aggregation induced osteochondrogenic differentiation, further enhanced by BMP-2 stimulation. Ectopic implantation displayed a cascade of events that closely resembled the natural endochondral process resulting in bone ossicle formation. Assessment in a critical size long-bone defect in immunodeficient mice demonstrated successful bridging of the defect within 4 weeks, with active contribution of the implanted cells. In short, the presented serum-free process represents a biomimetic strategy, resulting in a cartilage tissue intermediate that, upon implantation, robustly leads to the healing of a large long-bone defect. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.
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Excessive dietary intake of vitamin A reduces skull bone thickness in mice
Öhman, Caroline; Calounova, Gabriela; Rasmusson, Annica; Andersson, Göran; Pejler, Gunnar; Melhus, Håkan
2017-01-01
Calvarial thinning and skull bone defects have been reported in infants with hypervitaminosis A. These findings have also been described in humans, mice and zebrafish with loss-of-function mutations in the enzyme CYP26B1 that degrades retinoic acid (RA), the active metabolite of vitamin A, indicating that these effects are indeed caused by too high levels of vitamin A and that evolutionary conserved mechanisms are involved. To explore these mechanisms, we have fed young mice excessive doses of vitamin A for one week and then analyzed the skull bones using micro computed tomography, histomorphometry, histology and immunohistochemistry. In addition, we have examined the effect of RA on gene expression in osteoblasts in vitro. Compared to a standard diet, a high dietary intake of vitamin A resulted in a rapid and significant reduction in calvarial bone density and suture diastasis. The bone formation rate was almost halved. There was also increased staining of tartrate resistant acid phosphatase in osteocytes and an increased perilacunar matrix area, indicating osteocytic osteolysis. Consistent with this, RA induced genes associated with bone degradation in osteoblasts in vitro. Moreover, and in contrast to other known bone resorption stimulators, vitamin A induced osteoclastic bone resorption on the endocranial surfaces. PMID:28426756
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Shen, Jia; James, Aaron W.; Zhang, Xinli; Pang, Shen; Zara, Janette N.; Asatrian, Greg; Chiang, Michael; Lee, Min; Khadarian, Kevork; Nguyen, Alan; Lee, Kevin S.; Siu, Ronald K.; Tetradis, Sotirios; Ting, Kang; Soo, Chia
2017-01-01
The differentiation factor NEL-like molecule-1 (NELL-1) has been reported as osteoinductive in multiple in vivo preclinical models. Bone morphogenetic protein (BMP)-2 is used clinically for skeletal repair, but in vivo administration can induce abnormal, adipose-filled, poor-quality bone. We demonstrate that NELL-1 combined with BMP2 significantly optimizes osteogenesis in a rodent femoral segmental defect model by minimizing the formation of BMP2-induced adipose-filled cystlike bone. In vitro studies using the mouse bone marrow stromal cell line M2-10B4 and human primary bone marrow stromal cells have confirmed that NELL-1 enhances BMP2-induced osteogenesis and inhibits BMP2-induced adipogenesis. Importantly, the ability of NELL-1 to direct BMP2-treated cells toward osteogenesis and away from adipogenesis requires intact canonical Wnt signaling. Overall, these studies establish the feasibility of combining NELL-1 with BMP2 to improve clinical bone regeneration and provide mechanistic insight into canonical Wnt pathway activity during NELL-1 and BMP2 osteogenesis. The novel abilities of NELL-1 to stimulate Wnt signaling and to repress adipogenesis may highlight new treatment approaches for bone loss in osteoporosis. PMID:26772960
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Development of electrospun bone-mimetic matrices for bone regenerative applications
NASA Astrophysics Data System (ADS)
Phipps, Matthew Christopher
Although bone has a dramatic capacity for regeneration, certain injuries and procedures present defects that are unable to heal properly, requiring surgical intervention to induce and support osteoregeneration. Our research group has hypothesized that the development of a biodegradable material that mimics the natural composition and architecture of bone extracellular matrix has the potential to provide therapeutic benefit to these patients. Utilizing a process known as electrospinning, our lab has developed a bone-mimetic matrix (BMM) consisting of composite nanofibers of the mechanically sta-ble polymer polycaprolactone (PCL), and the natural bone matrix molecules type-I colla-gen and hydroxyapatite nanocrystals (HA). We herein show that BMMs supported great-er adhesion, proliferation, and integrin activation of mesenchymal stem cells (MSCs), the multipotent bone-progenitor cells within bone marrow and the periosteum, in comparison to electrospun PCL alone. These cellular responses, which are essential early steps in the process of bone regeneration, highlight the benefits of presenting cells with natural bone molecules. Subsequently, evaluation of new bone formation in a rat cortical tibia defect showed that BMMs are highly osteoconductive. However, these studies also revealed the inability of endogenous cells to migrate within electrospun matrices due to the inherently small pore sizes. To address this limitation, which will negatively impact the rate of scaf-fold-to-bone turnover and inhibit vascularization, sacrificial fibers were added to the ma-trix. The removal of these fibers after fabrication resulted in BMMs with larger pores, leading to increased infiltration of MSCs and endogenous bone cells. Lastly, we evaluat-ed the potential of our matrices to stimulate the recruitment of MSCs, a vital step in bone healing, through the sustained delivery of platelet derived growth factor-BB (PDGF-BB). BMMs were found to adsorb and subsequently release greater quantities of PDGF-BB, compared to PCL scaffolds, over an 8-week interval. The released PDGF-BB retained its bioactivity, stimulating MSC chemotaxis in two separate assays. Collectively, these re-sults suggest that electrospun matrices incorporating the bone matrix molecules collagen I and HA, with sacrificial fibers, provide a favorable scaffold for MSC survival and infil-tration as well as the ability to sequester PDGF-BB from solution, leading to sustained local delivery and MSC chemotaxis.
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Saxena, Amol; DiDomenico, Lawrence A; Widtfeldt, Arthur; Adams, Todd; Kim, Will
2005-01-01
This study assessed arthrodesis procedures performed in the foot and ankle of high-risk patients following implantation of an internal electrical bone stimulator. Criteria defining patients as "high risk" included diabetes, obesity, habitual tobacco and/or alcohol use, immunosuppressive therapy, and previous history of nonunion. Standard arthrodesis protocol of bone graft and internal fixation was supplemented with the implantable electrical bone stimulator. A retrospective, multicenter review was conducted of 26 patients (28 cases) who underwent 28 forefoot and hindfoot arthrodeses from 1998 to 2002. Complete fusion was defined as bony trabeculation across the joint, lack of motion across the joint, maintenance of hardware/fixation, and absence of radiographic signs of nonunion or pseudoarthrosis. Radiographic consolidation was achieved in 24 of the 28 cases at an average 10.3+/-4.0 weeks. Followup averaged 27.2 months. Complications included 2 patients who sustained breakage of the cables to the bone stimulator. Five patients underwent additional surgery. Four of the 5 patients had additional surgery in order to achieve arthrodesis. All 4 went on to subsequent arthrodesis. This study demonstrates how arthrodesis of the foot and ankle may be enhanced by the use of implantable electrical bone stimulation.
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Effect of low-magnitude, high-frequency vibration on osteocytes in the regulation of osteoclasts
Lau, Esther; Al-Dujaili, Saja; Guenther, Axel; Liu, Dawei; Wang, Liyun; You, Lidan
2010-01-01
Osteocytes are well evidenced to be the major mechanosensor in bone, responsible for sending signals to the effector cells (osteoblasts and osteoclasts) that carry out bone formation and resorption. Consistent with this hypothesis, it has been shown that osteocytes release various soluble factors (e.g. transforming growth factor-β, nitric oxide, and prostaglandins) that influence osteoblastic and osteoclastic activities when subjected to a variety of mechanical stimuli, including fluid flow, hydrostatic pressure, and mechanical stretching. Recently, low-magnitude, high-frequency (LMHF) vibration (e.g., acceleration less than <1g, where g=9.98 m/s2, at 20-90 Hz) has gained much interest as studies have shown that such mechanical stimulation can positively influence skeletal homeostasis in animals and humans. Although the anabolic and anti-resorptive potential of LMHF vibration is becoming apparent, the signaling pathways that mediate bone adaptation to LMHF vibration are unknown. We hypothesize that osteocytes are the mechanosensor responsible for detecting the vibration stimulation and producing soluble factors that modulate the activity of effector cells. Hence, we applied low-magnitude (0.3g) vibrations to osteocyte-like MLO-Y4 cells at various frequencies (30, 60, 90 Hz) for 1 hour. We found that osteocytes were sensitive to this vibration stimulus at the transcriptional level: COX-2 maximally increased by 344% at 90 Hz, while RANKL decreased most significantly (-55%, p<0.01) at 60 Hz. Conditioned medium collected from the vibrated MLO-Y4 cells attenuated the formation of large osteoclasts (≥10 nuclei) by 36% (p<0.05) and the amount of osteoclastic resorption by 20% (p=0.07). The amount of soluble RANKL (sRANKL) in the conditioned medium was found to be 53% lower in the vibrated group (p<0.01), while PGE2 release was also significantly decreased (-61%, p<0.01). We conclude that osteocytes are able to sense LMHF vibration and respond by producing soluble factors that inhibit osteoclast formation. PMID:20211285
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Bouleftour, Wafa; Bouet, Guenaelle; Granito, Renata Neves; Thomas, Mireille; Linossier, Marie-Thérèse; Vanden-Bossche, Arnaud; Aubin, Jane E; Lafage-Proust, Marie-Hélène; Vico, Laurence; Malaval, Luc
2015-03-01
Osteopontin (OPN) and bone sialoprotein (BSP) are coexpressed in osteoblasts and osteoclasts, and display overlapping properties. We used daily injection of parathyroid hormone 1-84 (iPTH) over the calvaria of BSP knockout (-/-) mice to investigate further their functional specificity and redundancy. iPTH stimulated bone formation in both +/+ and -/- mice, increasing to the same degree periosteum, osteoid and total bone thickness. Expression of OPN, osterix, osteocalcin (OCN) and DMP1 was also increased by iPTH in both genotypes. In contrast to +/+, calvaria cell cultures from -/- mice revealed few osteoblast colonies, no mineralization and little expression of OCN, MEPE or DMP1. In contrast, OPN levels were 5× higher in -/- versus +/+ cultures. iPTH increased alkaline phosphatase (ALP) activity in cell cultures of both genotypes, with higher OCN and the induction of mineralization in -/- cultures. siRNA blocking of OPN expression did not alter the anabolic action of the hormone in BSP +/+ calvaria, while it blunted iPTH effects in -/- mice, reduced to a modest increase in periosteum thickness. In -/- (not +/+) cell cultures, siOPN blocked the stimulation by iPTH of ALP activity and OCN expression, as well as the induction of mineralization. Thus, full expression of either OPN or BSP is necessary for the anabolic effect of PTH at least in the ectopic calvaria injection model. This suggests that OPN may compensate for the lack of BSP in the response to this hormonal challenge, and provides evidence of functional overlap between these cognate proteins. © 2014 Wiley Periodicals, Inc., A Wiley Company.
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Zeng, Sen; Ye, Jianhua; Cui, Zhixiang; Si, Junhui; Wang, Qianting; Wang, Xiaofeng; Peng, Kaiping; Chen, Wenzhe
2017-08-01
As one of the stimulators on bone formation, osteogenic growth peptide (OGP) improves both proliferation and differentiation of the bone cells in vitro and in vivo. The aim of this work was the preparation of three dimensional porous poly(lactic acid) (PLA) scaffold with high porosity from PLA-dioxane-water ternary system with the use of vacuum-assisted solvent casting, phase separation, solvent extraction and particle leaching methods. Then, by surface coating of PLA scaffold with chitosan (CS)/OGP solution, biofunctionalization of PLA scaffold had been completed for application in bone regeneration. The effects of frozen temperature (-20, -50, -80°C) and PLA solution concentration (10, 12, 14wt%) on the microstructure, water absorption, porosity, hydrophilicity, mechanical properties, and biocompatibility of PLA and CS/OGP/PLA scaffold were investigated. Results showed that both PLA and CS/OGP/PLA scaffolds have an interconnected network structure and a porosity of up to 96.1% and 91.5%, respectively. The CS/OGP/PLA scaffold exhibited better hydrophilicity and mechanical properties than that of uncoated PLA scaffold. Moreover, the results of cell culture test showed that CS/OGP coating could stimulate the proliferation and growth of osteoblast cells on CS/OGP/PLA scaffold. These finding suggested that the surface biofunctionalization by CS/OGP coating layer could be an effective method on enhancing cell adhesion to synthetic polymer-based scaffolds in tissue engineering application and the developed porous CS/OGP/PLA scaffold should be considered as alternative biomaterials for bone regeneration. Copyright © 2017 Elsevier B.V. All rights reserved.
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Lee, Eun-Jung; Kim, Jung-Lye; Kim, Yun-Ho; Kang, Min-Kyung; Gong, Ju-Hyun; Kang, Young-Hee
2014-09-15
Bone-remodeling imbalance induced by increased osteoclast formation and bone resorption is known to cause skeletal diseases such as osteoporosis. The reduction of estrogen levels at menopause is one of the strongest risk factors developing postmenopausal osteoporosis. This study investigated osteoprotective effects of the dihydrochalcone phloretin found in apple tree leaves on bone loss in ovariectomized (OVX) C57BL/6 female mice as a model for postmenopausal osteoporosis. OVX demoted bone mineral density (BMD) of mouse femurs, reduced serum 17β-estradiol level and enhanced serum receptor activator of NF-κB ligand (RANKL)/osteoprotegerin ratio with uterine atrophy. Oral administration of 10 mg/kg phloretin to OVX mice for 8 weeks improved such effects, compared to sham-operated mice. Phloretin attenuated TRAP activity and cellular expression of β3 integrin and carbonic anhydrase II augmented in femoral bone tissues of OVX mice. This study further examined that osteogenic activity of phloretin in RANKL-differentiated Raw 264.7 macrophages into mature osteoclasts. Phloretin at 1-20 μM stimulated Smac expression and capase-3 activation concurrently with nuclear fragmentation of multi-nucleated osteoclasts, indicating that this compound promoted osteoclast apoptosis. Consistently, phloretin enhanced bcl-2 induction but diminished bax expression. Furthermore, phloretin activated ASK-1-diverged JNK and p38 MAPK signaling pathways in mature osteoclasts, whereas it dose-dependently inhibited the RANKL-stimulated activation of ERK. Therefore, phloretin manipulated ASK-1-MAPK signal transduction leading to transcription of apoptotic genes. Phloretin was effective in preventing estrogen deficiency-induced osteoclastogenic resorption. Copyright © 2014 Elsevier GmbH. All rights reserved.
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2009-01-01
A 42-year-old Mediterranean male presented complaining of inability to sustain good oral care at the posterior aspect of the lower right jaw. The main problems were food impaction in the area and the subsequent malodor. The patient reported remarkable medical history. Clinical examination revealed local erytherma with noticeable bone defect distal to the second molar with obvious defect in the mesial wall of the third molar; the penetration depth was found to be up to 6 mm. Radiological evaluation confirmed the defect and it was attributed to the mesioangularly partially impacted lower third molar. It was decided that third molar should be extracted and concentrate of the patient's growth factors (PRGF) to be applied into the bony defect to stimulate bone regeneration and promote healing. The third molar tooth was, then, removed surgically and the PRGF, which was prepared preoperatively, was implanted in the socket. At the first postoperative day, moderate pain was the main complaint and was controlled by NSAIDs. One week postoperatively, the sutures were removed and there was good tissue healing on examination. On the fiftieth postoperative day, radiographic evaluation took place and showed noticeable enhancement of density and radio-opacity in the third molar socket area, in comparison with the baseline image. Further, clinical examination showed significant reduction of periodontal pocketing and evidence of new bone formation. In conclusion, PRGF was very successful in stimulating bone regeneration and promote healing following dental extraction. PMID:20062651
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Gautam, Abnish K; Bhargavan, Biju; Tyagi, Abdul M; Srivastava, Kamini; Yadav, Dinesh K; Kumar, Manmeet; Singh, Akanksha; Mishra, Jay S; Singh, Amar Bahadur; Sanyal, Sabyasachi; Maurya, Rakesh; Manickavasagam, Lakshmi; Singh, Sheelendra P; Wahajuddin, Wahajuddin; Jain, Girish K; Chattopadhyay, Naibedya; Singh, Divya
2011-04-01
Dietary soy isoflavones including genistein and daidzein have been shown to have favorable effects during estrogen deficiency in experimental animals and humans. We have evaluated osteogenic effect of cladrin and formononetin, two structurally related methoxydaidzeins found in soy food and other natural sources. Cladrin, at as low as 10 nM, maximally stimulated both osteoblast proliferation and differentiation by activating MEK-Erk pathway. On the other hand, formononetin maximally stimulated osteoblast differentiation at 100 nM that involved p38 MAPK pathway but had no effect on osteoblast proliferation. Unlike daidzein, these two compounds neither activated estrogen receptor in osteoblast nor had any effect on osteoclast differentiation. Daily oral administration of each of these compounds at 10.0 mg kg(-1) day(-1) dose to recently weaned female Sprague-Dawley rats for 30 consecutive days, increased bone mineral density at various anatomic positions studied. By dynamic histomorphometry of bone, we observed that rats treated with cladrin exhibited increased mineral apposition and bone formation rates compared with control, while formononetin had no effect. Cladrin had much better plasma bioavailability compared with formononetin. None of these compounds exhibited estrogen agonistic effect in uteri. Our data suggest that cladrin is more potent among the two in promoting parameters of peak bone mass achievement, which could be attributed to its stimulatory effect on osteoblast proliferation and better bioavailability. To the best of our knowledge, this is the first attempt to elucidate structure-activity relationship between the methoxylated forms of daidzein and their osteogenic effects. Copyright © 2011 Elsevier Inc. All rights reserved.
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Figeac, Florence; Andersen, Ditte C; Nipper Nielsen, Casper A; Ditzel, Nicholas; Sheikh, Søren P; Skjødt, Karsten; Kassem, Moustapha; Jensen, Charlotte H; Abdallah, Basem M
2018-05-01
Soluble delta-like 1 homolog (DLK1) is a circulating protein that belongs to the Notch/Serrate/delta family, which regulates many differentiation processes including osteogenesis and adipogenesis. We have previously demonstrated an inhibitory effect of DLK1 on bone mass via stimulation of bone resorption and inhibition of bone formation. Further, serum DLK1 levels are elevated and positively correlated to bone turnover markers in estrogen (E)-deficient rodents and women. In this report, we examined whether inhibition of serum DLK1 activity using a neutralizing monoclonal antibody protects from E deficiency-associated bone loss in mice. Thus, we generated mouse monoclonal anti-mouse DLK1 antibodies (MAb DLK1) that enabled us to reduce and also quantitate the levels of bioavailable serum DLK1 in vivo. Ovariectomized (ovx) mice were injected intraperitoneally twice weekly with MAb DLK1 over a period of one month. DEXA-, microCT scanning, and bone histomorphometric analyses were performed. Compared to controls, MAb DLK1 treated ovx mice were protected against ovx-induced bone loss, as revealed by significantly increased total bone mass (BMD) due to increased trabecular bone volume fraction (BV/TV) and inhibition of bone resorption. No significant changes were observed in total fat mass or in the number of bone marrow adipocytes. These results support the potential use of anti-DLK1 antibody therapy as a novel intervention to protect from E deficiency associated bone loss. Copyright © 2018 Elsevier Inc. All rights reserved.
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Algate, K; Haynes, D R; Bartold, P M; Crotti, T N; Cantley, M D
2016-10-01
Periodontitis is the most common bone loss pathology in adults and if left untreated is responsible for premature tooth loss. Cytokines, such as tumour necrosis factor-α (TNFα), involved in the chronic inflammatory response within the periodontal gingiva, significantly influence the normal bone remodelling processes. In this review, the effects of TNFα on bone metabolism in periodontitis are evaluated in relation to its direct and indirect actions on bone cells including osteoclasts, osteoblasts and osteocytes. Evidence published to date suggests a potent catabolic role for TNFα through the stimulation of osteoclastic bone resorption as well as the suppression of osteoblastic bone formation and osteocytic survival. However, the extent and timing of TNFα exposure in vitro and in vivo greatly influences its effect on skeletal cells, with contradictory anabolic activity observed with TNFα in a number of studies. None the less, it is evident that managing the chronic inflammatory response in addition to the deregulated bone metabolism is required to improve periodontal and inflammatory bone loss treatments. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
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Chen, Zonggang; Liu, Huanye; Liu, Xi; Cui, Fu-Zhai
2011-12-15
An injectable and self-setting bone repair materials (nano-hydroxyapatite/collagen/calcium sulfate hemihydrate, nHAC/CSH) was developed in this study. The nano-hydroxyapatite/collagen (nHAC) composite, which is the mineralized fibril by self-assembly of nano-hydrocyapatite and collagen, has the same features as natural bone in both main hierarchical microstructure and composition. It is a bioactive osteoconductor due to its high level of biocompatibility and appropriate degradation rate. However, this material lacks handling characteristics because of its particle or solid-preformed block shape. Herein, calcium sulfate hemihydrate (CSH) was introduced into nHAC to prepare an injectable and self-setting in situ bone repair materials. The morphology of materials was observed using SEM. Most important and interesting of all, calcium sulfate dihydrate (CSD), which is not only the reactant of preparing CSH but also the final solidified product of CSH, was introduced into nHAC as setting accelerator to regulate self-setting properties of injectable nHAC/CSH composite, and thus the self-setting time of nHAC/CSH composite can be regulated from more than 100 min to about 30 min and even less than 20 min by adding various amount of setting accelerator. The compressive properties of bone graft substitute after final setting are similar to those of cancellous bone. CSD as an excellent setting accelerator has no significant effect on the mechanical property and degradability of bone repair materials. In vitro biocompatibility and in vivo histology studies demonstrated that the nHAC/CSH composite could provide more adequate stimulus for cell adhesion and proliferation, embodying favorable cell biocompatibility and a strong ability to accelerate bone formation. It can offer a satisfactory biological environment for growing new bone in the implants and for stimulating bone formation. Copyright © 2011 Wiley Periodicals, Inc.
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Ishack, Stephanie; Mediero, Aranzazu; Wilder, Tuere; Ricci, John L; Cronstein, Bruce N
2017-02-01
Bone defects resulting from trauma or infection need timely and effective treatments to restore damaged bone. Using specialized three-dimensional (3D) printing technology we have created custom 3D scaffolds of hydroxyapatite (HA)/beta-tri-calcium phosphate (β-TCP) to promote bone repair. To further enhance bone regeneration we have coated the scaffolds with dipyridamole, an agent that increases local adenosine levels by blocking cellular uptake of adenosine. Nearly 15% HA:85% β-TCP scaffolds were designed using Robocad software, fabricated using a 3D Robocasting system, and sintered at 1100°C for 4 h. Scaffolds were coated with BMP-2 (200 ng mL -1 ), dypiridamole 100 µM or saline and implanted in C57B6 and adenosine A2A receptor knockout (A2AKO) mice with 3 mm cranial critical bone defects for 2-8 weeks. Dipyridamole release from scaffold was assayed spectrophotometrically. MicroCT and histological analysis were performed. Micro-computed tomography (microCT) showed significant bone formation and remodeling in HA/β-TCP-dipyridamole and HA/β-TCP-BMP-2 scaffolds when compared to scaffolds immersed in vehicle at 2, 4, and 8 weeks (n = 5 per group; p ≤ 0.05, p ≤ 0.05, and p ≤ 0.01, respectively). Histological analysis showed increased bone formation and a trend toward increased remodeling in HA/β-TCP- dipyridamole and HA/β-TCP-BMP-2 scaffolds. Coating scaffolds with dipyridamole did not enhance bone regeneration in A2AKO mice. In conclusion, scaffolds printed with HA/β-TCP promote bone regeneration in critical bone defects and coating these scaffolds with agents that stimulate A2A receptors and growth factors can further enhance bone regeneration. These coated scaffolds may be very useful for treating critical bone defects due to trauma, infection or other causes. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 366-375, 2017. © 2015 Wiley Periodicals, Inc.
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Promoting Endochondral Bone Repair Using Human Osteoarthritic Articular Chondrocytes.
Bahney, Chelsea S; Jacobs, Linsey; Tamai, Robert; Hu, Diane; Luan, Tammy F; Wang, Miqi; Reddy, Sanjay; Park, Michelle; Limburg, Sonja; Kim, Hubert T; Marcucio, Ralph; Kuo, Alfred C
2016-03-01
Current tissue engineering strategies to heal critical-size bone defects through direct bone formation are limited by incomplete integration of grafts with host bone and incomplete graft vascularization. An alternative strategy for bone regeneration is the use of cartilage grafts that form bone through endochondral ossification. Endochondral cartilages stimulate angiogenesis and are remodeled into bone, but are found in very small quantities in growth plates and healing fractures. We sought to develop engineered endochondral cartilage grafts using osteoarthritic (OA) articular chondrocytes as a cell source. Such chondrocytes often undergo hypertrophy, which is a characteristic of endochondral cartilages. We compared the ability of unmodified human OA (hOA) cartilage and cartilage grafts formed in vitro from hOA chondrocytes to undergo endochondral ossification in mice. Scaffold-free engineered chondrocyte grafts were generated by pelleting chondrocytes, followed by culture with transforming growth factor-β1 (TGF-β1) and bone morphogenetic protein 4. Samples derived from either primary or passaged chondrocytes were implanted subcutaneously into immunocompromised mice. Grafts derived from passaged chondrocytes from three patients were implanted into critical-size tibial defects in mice. Bone formation was assessed with histology after 4 weeks of implantation. The composition of tibial repair tissue was quantified with histomorphometry. Engineered cartilage grafts generated from passaged OA chondrocytes underwent endochondral ossification after implantation either subcutaneously or in bone. Cartilage grafts integrated with host bone at 15 out of 16 junctions. Grafts variably remodeled into woven bone, with the proportion of bony repair tissue in tibial defects ranging from 22% to 85% (average 48%). Bony repair tissue bridged the tibial defects in half of the animals. In contrast, unmodified OA cartilage and engineered grafts formed from primary chondrocytes did not undergo endochondral ossification in vivo. hOA chondrocytes can adopt an endochondral phenotype after passaging and TGF-β superfamily treatment. Engineered endochondral cartilage grafts can integrate with host bone, undergo ossification, and heal critical-size long-bone defects in a mouse model. However, additional methods to further enhance ossification of these grafts are required before the clinical translation of this approach.
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Osteoporosis Prevention and Management.
Pai, Muralidhar V
2017-08-01
Osteoporosis, defined by BMD at the hip or lumbar spine that is less than or equal to 2.5 standard deviations below the mean BMD of a young-adult reference population, is the most common bone disease in humans affecting both sexes and all races. It's a silent killer affecting the quality of life due to fractures and postural changes. In osteoporosis there is an imbalance between bone formation and bone resorption in favor of latter. Preventive measures and treatments are available to combat this evil. Counseling is the integral part of prevention as well as treatment of osteoporosis. Preventive strategy includes life style changes, exercise, intake of calcium and vitamin D, avoiding alcohol, smoking and excessive intake of salt. Estrogen therapy/estrogen+progesterone therapy (ET/EPT) is no longer recommended as a first-line therapy for the prevention of osteoporosis. They may be used in the therapy for osteoporosis in women under 60. Diagnosis and classification are made by assessment of BMD using DEXA or ultrasound and laboratory investigations. Management includes estimation of 10-year fracture risk using FRAX, life style and diet modification and pharmacological therapy. The drugs used in osteoporosis may be those that inhibit bone resorption-bisphosphonates, denosumab, calcitonin, SERMs, estrogen and progesterone-or that stimulate bone formation-PTH, Teriparatide. Combination therapies are not recommended as they do not have proven additional BMD/fracture benefits. No therapy should be indefinite in duration. There are no uniform recommendations to all patients. Duration decisions need to be individualized. While on treatment monitoring should be done with BMD assessment by DEXA/ultrasound and bone turnover markers.
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Pleiotropic effects of statins on the treatment of chronic periodontitis--a systematic review.
Estanislau, Ilanna Mara Gomes; Terceiro, Icrólio Ribeiro Colares; Lisboa, Mario Roberto Pontes; Teles, Patrícia de Barros; Carvalho, Rosimary de Sousa; Martins, Ricardo Souza; Moreira, Maria Mônica Studart Mendes
2015-06-01
Statins are inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase and are an important group of hypolipidaemic drugs, widely used in the treatment of hypercholesterolaemia and cardiovascular disease. Some studies have shown that statins are able to modulate inflammation and alveolar bone loss. In order to evaluate whether statins could influence periodontal treatment, improving the clinical and radiographic parameters in chronic periodontitis, a systematic review was conducted in the databases PUBMED and BIREME, searching for articles in English and Portuguese, published between the years 2004 and 2014, using the combined keywords statin, periodontal disease, periodontitis and alveolar bone. Studies regarding the treatment of chronic periodontitis in humans, blind or double-blind, retrospective cohort or randomized controlled trials that used statins topically or systemically were selected. Statins have important anti-inflammatory and immune effects, reducing levels of C-reactive protein and matrix metalloproteinases and their intermediate products, such as tumour necrosis factor-α, and are also able to inhibit the adhesion and extravasation of leukocytes, which block the co-stimulation of T cells. Statins reduce bone resorption by inhibiting osteoclast formation and lead to increased apoptosis of these cells. The effect of statins on bone formation is related to the increased gene expression of bone morphogenetic protein in osteoblasts. Although we found biological mechanisms and clinical results that show lower alveolar bone loss and reduction of clinical signs of inflammation, further studies are needed to evaluate the clinical applicability of statins in the routine treatment of chronic periodontitis. © 2014 The British Pharmacological Society.
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Lactoferrin – A Novel Bone Growth Factor
Naot, Dorit; Grey, Andrew; Reid, Ian R; Cornish, Jillian
2005-01-01
Lactoferrin is an iron-binding glycoprotein that belongs to the transferrin family. It is present in breast milk, in epithelial secretions, and in the secondary granules of neutrophils. In healthy subjects lactoferrin circulates at concentrations of 2–7 x 10−6 g/ml. Lactoferrin is a pleiotropic factor with potent antimicrobial and immunomodulatory activities. Recently, we have shown that lactoferrin can also promote bone growth. At physiological concentrations, lactoferrin potently stimulates the proliferation and differentiation of primary osteoblasts and also acts as a survival factor inhibiting apoptosis induced by serum withdrawal. Lactoferrin also affects osteoclast formation and, in murine bone marrow culture, lactoferrin potently inhibits osteoclastogenesis. In vivo, local injection of lactoferrin above the hemicalvaria of adult mice results in substantial increases in the dynamic histomorphometric indices of bone formation and bone area. The mitogenic effect of lactoferrin in osteoblast-like cells is mediated mainly through LRP1, a member of the family of low-density lipoprotein receptor-related proteins that are primarily known as endocytic receptors. Using confocal laser scanning microscopy, we demonstrated that fluorescently labeled lactoferrin is endocytosed and can be visualized in the cytoplasm of primary osteoblastic cells. Lactoferrin also induces activation of p42/44 MAPK signaling in primary osteoblasts, but the two pathways seem to operate independently as activation of MAPK signaling, but not endocytosis, is necessary for the mitogenic effect of lactoferrin. We conclude that lactoferrin may have a physiological role in bone growth and healing, and a potential therapeutic role as an anabolic factor in osteoporosis. PMID:16012127
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de Peppo, Giuseppe Maria; Sladkova, Martina; Sjövall, Peter; Palmquist, Anders; Oudina, Karim; Hyllner, Johan; Thomsen, Peter; Petite, Hervé; Karlsson, Camilla
2013-01-01
Bone tissue engineering represents a promising strategy to obviate bone deficiencies, allowing the ex vivo construction of bone substitutes with unprecedented potential in the clinical practice. Considering that in the human body cells are constantly stimulated by chemical and mechanical stimuli, the use of bioreactor is emerging as an essential factor for providing the proper environment for the reproducible and large-scale production of the engineered substitutes. Human mesenchymal stem cells (hMSCs) are experimentally relevant cells but, regardless the encouraging results reported after culture under dynamic conditions in bioreactors, show important limitations for tissue engineering applications, especially considering their limited proliferative potential, loss of functionality following protracted expansion, and decline in cellular fitness associated with aging. On the other hand, we previously demonstrated that human embryonic stem cell-derived mesodermal progenitors (hES-MPs) hold great potential to provide a homogenous and unlimited source of cells for bone engineering applications. Based on prior scientific evidence using different types of stem cells, in the present study we hypothesized that dynamic culture of hES-MPs in a packed bed/column bioreactor had the potential to affect proliferation, expression of genes involved in osteogenic differentiation, and matrix mineralization, therefore resulting in increased bone-like tissue formation. The reported findings suggest that hES-MPs constitute a suitable alternative cell source to hMSCs and hold great potential for the construction of bone substitutes for tissue engineering applications in clinical settings.
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Freundlich, Michael; Alonzo, Evelyn; Bellorin-Font, Ezequiel; Weisinger, Jose R
2005-07-01
Patients with nephrotic syndrome (NS), even with normal GFR, often display altered mineral homeostasis and abnormal bone histology. However, the latter, mostly osteomalacia and increased bone resorption, cannot be readily explained by the prevalent concentrations of parathyroid hormone and vitamin D metabolites. The transmembrane receptor activator of NF-kappaB ligand (RANKL) of osteoblasts is essential for osteoclast formation and differentiation. Osteoblasts activity and the expression of RANKL were tested in cultures of normal human osteoblasts with sera obtained from patients with NS and normal GFR (129 +/- 26 ml/min per 1.73 m2) during relapse and remission of their NS. Osteoblasts that were cultured in vitro with sera during relapse displayed elevated concentrations of alkaline phosphatase (AP) and increased expression of RANKL. By contrast, during remission, AP concentrations were significantly lower (P < 0.05) and RANKL expression notably attenuated or absent. AP correlated with the proteinuria (r = 0.5, P < 0.05) and was not significantly affected by the therapeutic administration of corticosteroids. Whereas parathyroid hormone levels were normal (35 +/- 21 pg/ml), the serum markers of bone formation (osteocalcin and bone-specific alkaline phosphatase) were lower during relapse compared with remission. Thus, sera from patients with NS and normal GFR stimulate the activity of osteoblasts and upregulate their expression of RANKL. These alterations, more prominent during clinically active NS, are transient and reversible upon remission. These disturbances of bone biology may play an important pathogenic role in the abnormal bone histology observed in patients with NS even before a decline in GFR occurs.
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Todeschi, Maria Rosa; El Backly, Rania; Capelli, Chiara; Daga, Antonio; Patrone, Eugenio; Introna, Martino; Cancedda, Ranieri
2015-01-01
Umbilical cord mesenchymal stem cells (UC-MSCs) show properties similar to bone marrow mesenchymal stem cells (BM-MSCs), although controversial data exist regarding their osteogenic potential. We prepared clinical-grade UC-MSCs from Wharton's Jelly and we investigated if UC-MSCs could be used as substitutes for BM-MSCs in muscoloskeletal regeneration as a more readily available and functional source of MSCs. UC-MSCs were loaded onto scaffolds and implanted subcutaneously (ectopically) and in critical-sized calvarial defects (orthotopically) in mice. For live cell-tracking experiments, UC-MSCs were first transduced with the luciferase gene. Angiogenic properties of UC-MSCs were tested using the mouse metatarsal angiogenesis assay. Cell secretomes were screened for the presence of various cytokines using an array assay. Analysis of implanted scaffolds showed that UC-MSCs, contrary to BM-MSCs, remained detectable in the implants for 3 weeks at most and did not induce bone formation in an ectopic location. Instead, they induced a significant increase of blood vessel ingrowth. In agreement with these observations, UC-MSC-conditioned medium presented a distinct and stronger proinflammatory/chemotactic cytokine profile than BM-MSCs and a significantly enhanced angiogenic activity. When UC-MSCs were orthotopically transplanted in a calvarial defect, they promoted increased bone formation as well as BM-MSCs. However, at variance with BM-MSCs, the new bone was deposited through the activity of stimulated host cells, highlighting the importance of the microenvironment on determining cell commitment and response. Therefore, we propose, as therapy for bone lesions, the use of allogeneic UC-MSCs by not depositing bone matrix directly, but acting through the activation of endogenous repair mechanisms. PMID:25685989
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Oortgiesen, Daniël A W; Meijer, Gert J; Bronckers, Antonius L J J; Walboomers, X Frank; Jansen, John A
2013-03-01
Enamel matrix derivative (EMD) has proven to enhance periodontal regeneration; however, its effect is mainly restricted to the soft periodontal tissues. Therefore, to stimulate not only the soft tissues, but also the hard tissues, in this study EMD is combined with an injectable calcium phosphate cement (CaP; bone graft material). The aim was to evaluate histologically the healing of a macroporous CaP in combination with EMD. Intrabony, three-wall periodontal defects (2 × 2 × 1.7 mm) were created mesial of the first upper molar in 15 rats (30 defects). Defects were randomly treated according to one of the three following strategies: EMD, calcium phosphate cement and EMD, or left empty. The animals were killed after 12 weeks, and retrieved samples were processed for histology and histomorphometry. Empty defects showed a reparative type of healing without periodontal ligament or bone regeneration. As measured with on a histological grading scale for periodontal regeneration, the experimental groups (EMD and CaP/EMD) scored equally, both threefold higher compared with empty defects. However, most bone formation was measured in the CaP/EMD group; addition of CAP to EMD significantly enhanced bone formation with 50 % compared with EMD alone. Within the limits of this animal study, the adjunctive use of EMD in combination with an injectable cement, although it did not affect epithelial downgrowth, appeared to be a promising treatment modality for regeneration of bone and ligament tissues in the periodontium. The adjunctive use of EMD in combination with an injectable cement appears to be a promising treatment modality for regeneration of the bone and ligament tissues in the periodontium.
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Sinder, B P; White, L E; Salemi, J D; Ominsky, M S; Caird, M S; Marini, J C; Kozloff, K M
2014-08-01
Treatments to reduce fracture rates in adults with osteogenesis imperfecta are limited. Sclerostin antibody, developed for treating osteoporosis, has not been explored in adults with OI. This study demonstrates that treatment of adult OI mice respond favorably to sclerostin antibody therapy despite retention of the OI-causing defect. Osteogenesis imperfecta (OI) is a heritable collagen-related bone dysplasia, characterized by brittle bones with increased fracture risk. Although OI fracture risk is greatest before puberty, adults with OI remain at risk of fracture. Antiresorptive bisphosphonates are commonly used to treat adult OI, but have shown mixed efficacy. New treatments which consistently improve bone mass throughout the skeleton may improve patient outcomes. Neutralizing antibodies to sclerostin (Scl-Ab) are a novel anabolic therapy that have shown efficacy in preclinical studies by stimulating bone formation via the canonical wnt signaling pathway. The purpose of this study was to evaluate Scl-Ab in an adult 6 month old Brtl/+ model of OI that harbors a typical heterozygous OI-causing Gly > Cys substitution on Col1a1. Six-month-old WT and Brtl/+ mice were treated with Scl-Ab (25 mg/kg, 2×/week) or Veh for 5 weeks. OCN and TRACP5b serum assays, dynamic histomorphometry, microCT and mechanical testing were performed. Adult Brtl/+ mice demonstrated a strong anabolic response to Scl-Ab with increased serum osteocalcin and bone formation rate. This anabolic response led to improved trabecular and cortical bone mass in the femur. Mechanical testing revealed Scl-Ab increased Brtl/+ femoral stiffness and strength. Scl-Ab was successfully anabolic in an adult Brtl/+ model of OI.
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Cytokines and growth factors which regulate bone cell function
NASA Astrophysics Data System (ADS)
Seino, Yoshiki
Everybody knows that growth factors are most important in making bone. Hormones enhance bone formation from a long distance. Growth factors promote bone formation as an autocrine or paracrine factor in nearby bone. BMP-2 through BMP-8 are in the TGF-β family. BMP makes bone by enchondral ossification. In bone, IGF-II is most abundant, second, TGF-β, and third IGF-I. TGF-β enhances bone formation mainly by intramembranous ossification in vivo. TGF-β affects both cell proliferation and differentiation, however, TGF-β mainly enhances bone formation by intramembranous ossification. Interestingly, TGF-β is increased by estrogen(E 2), androgen, vitamin D, TGF-β and FGF. IGF-I and IGF-II also enhance bone formation. At present it remains unclear why IGF-I is more active in bone formation than IGF-II, although IGF-II is more abundant in bone compared to IGF-I. However, if only type I receptor signal transduction promotes bone formation, the strong activity of IGF-I in bone formation is understandable. GH, PTH and E 2 promotes IGF-I production. Recent data suggest that hormones containing vitamin D or E 2 enhance bone formation through growth factors. Therefore, growth factors are the key to clarifying the mechanism of bone formation.
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The Nell-1 Growth Factor Stimulates Bone Formation by Purified Human Perivascular Cells
Zhang, Xinli; Péault, Bruno; Chen, Weiwei; Li, Weiming; Corselli, Mirko; James, Aaron W.; Lee, Min; Siu, Ronald K.; Shen, Pang; Zheng, Zhong; Shen, Jia; Kwak, Jinny; Zara, Janette N.; Chen, Feng; Zhang, Hong; Yin, Zack; Wu, Ben; Ting, Kang
2011-01-01
The search for novel sources of stem cells other than bone marrow mesenchymal stem cells (MSCs) for bone regeneration and repair has been a critical endeavor. We previously established an effective protocol to homogeneously purify human pericytes from multiple fetal and adult tissues, including adipose, bone marrow, skeletal muscle, and pancreas, and identified pericytes as a primitive origin of human MSCs. In the present study, we further characterized the osteogenic potential of purified human pericytes combined with a novel osteoinductive growth factor, Nell-1. Purified pericytes grown on either standard culture ware or human cancellous bone chip (hCBC) scaffolds exhibited robust osteogenic differentiation in vitro. Using a nude mouse muscle pouch model, pericytes formed significant new bone in vivo as compared to scaffold alone (hCBC). Moreover, Nell-1 significantly increased pericyte osteogenic differentiation, both in vitro and in vivo. Interestingly, Nell-1 significantly induced pericyte proliferation and was observed to have pro-angiogenic effects, both in vitro and in vivo. These studies suggest that pericytes are a potential new cell source for future efforts in skeletal regenerative medicine, and that Nell-1 is a candidate growth factor able to induce pericyte osteogenic differentiation. PMID:21615216
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Exercise interventions: defusing the world's osteoporosis time bomb.
Kai, Ming Chan; Anderson, Mary; Lau, Edith M. C.
2003-01-01
Osteoporosis is a major public health problem, affecting millions of people worldwide. The associated health care costs are growing in parallel with increases in elderly populations, and it is expected that the number of osteoporotic fractures will double over the next 50 years. The best way to address osteoporosis is prevention. Some interventions to maximize and preserve bone mass have multiple health benefits and are cost-effective. For example, modifications to diet and lifestyle can help to prevent osteoporosis, and could potentially lead to a significant decrease in fracture rates; and exercise is a valuable adjunct to programmes aimed at alleviating the risks and symptoms of osteoporosis. Practising exercise at a young age helps maximize the mineral density of bones while they are still growing and maturing, and continuing to excercise minimizes bone loss later in life. Not only does exercise improve bone health, it also increases muscle strength, coordination, balance, flexibility and leads to better overall health. Walking, aerobic exercise, and t'ai chi are the best forms of exercise to stimulate bone formation and strengthen the muscles that help support bones. Encouraging physical activity at all ages is therefore a top priority to prevent osteoporosis. PMID:14758410
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Naineni, Rohini; Ravi, Vishali; Subbaraya, Dwijendra Kocherlakota; Prasanna, Jammula Surya; Panthula, Veerendranath Reddy; Koduganti, Rekha Rani
2016-08-01
Alendronate (ALN), an aminobisphosphonate, inhibits osteoclastic bone resorption and also stimulates osteogenesis. Beta-Tricalcium Phosphate (β-TCP) is an osteoconductive graft material which provides a scaffold for bone formation and also a widely used drug delivery vehicle for growth factors and antibiotics. Drug delivery vehicles, like β-TCP, improve the potency of the drugs by specific local site delivery of the drug, optimal release characteristics and easy handling. The aim of the this study was to evaluate the bone formation potential of 400μg ALN delivered in β-TCP in the treatment of periodontal intra-osseous defects. Thirty patients with periodontal defects were randomly assigned to 400μg ALN + β-TCP + Saline (test) group and β-TCP + Saline (active-control) group. Clinical parameters like Clinical Attachment Level (CAL) gain, Probing Depth (PD) reduction, post-operative Gingival Recession (GR) were assessed from the baseline, 3 months and 6 months recordings. Radiographic parameters like Linear Bone Growth (LBG), Percentage Bone Fill (%BF), and change in alveolar crest height (ACH) were assessed from baseline and 6 months radiographs. Mean measurements in the ALN test group for CAL gain (3.4 ± 0.74 mm), PD reduction (4.33 ± 0.82 mm), LBG (2.88 ± 0.88 mm), and %BF (51.98 ± 15.84%) were significantly greater with a p-value <0.05 compared to the mean measurements of CAL gain (2.20 ± 0.86 mm), PD reduction (3.20 ± 1.15 mm), LBG (1.70 ± 0.39 mm), and %BF (30.35 ± 6.88%) of the control group. There was mild alveolar crestal apposition (0.32 ± 0.68 mm) in the ALN test group and mild alveolar crestal resorption (-0.24 ± 0.40 mm) in the control group. 400μg ALN combined with β-TCP bone graft material was effective in improving soft tissue parameters, inhibiting alveolar crestal resorption and enhancing bone formation, compared to β-TCP alone.
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Kawamoto, Kohei; Miyaji, Hirofumi; Nishida, Erika; Miyata, Saori; Kato, Akihito; Tateyama, Akito; Furihata, Tomokazu; Shitomi, Kanako; Iwanaga, Toshihiko; Sugaya, Tsutomu
2018-01-01
The 3-dimensional scaffold plays a key role in volume and quality of repair tissue in periodontal tissue engineering therapy. We fabricated a novel 3D collagen scaffold containing carbon-based 2-dimensional layered material, named graphene oxide (GO). The aim of this study was to characterize and assess GO scaffold for periodontal tissue healing of class II furcation defects in dog. GO scaffolds were prepared by coating the surface of a 3D collagen sponge scaffold with GO dispersion. Scaffolds were characterized using cytotoxicity and tissue reactivity tests. In addition, GO scaffold was implanted into dog class II furcation defects and periodontal healing was investigated at 4 weeks postsurgery. GO scaffold exhibited low cytotoxicity and enhanced cellular ingrowth behavior and rat bone forming ability. In addition, GO scaffold stimulated healing of dog class II furcation defects. Periodontal attachment formation, including alveolar bone, periodontal ligament-like tissue, and cementum-like tissue, was significantly increased by GO scaffold implantation, compared with untreated scaffold. The results suggest that GO scaffold is biocompatible and possesses excellent bone and periodontal tissue formation ability. Therefore, GO scaffold would be beneficial for periodontal tissue engineering therapy.
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de Melo, A; Justo, G Z; de Souza Queiroz, M L
2001-01-01
In this work, we investigated the effects of the proteic aggregated polymer of magnesium ammonium phospholinoleate-palmitoleate anhydride (MAPA) isolated from Aspergillus oryzae on the growth and differentiation of bone marrow granulocyte-macrophage progenitor cells (CFU-GM) in Listeriamonocytogenes-infected mice. A significant reduction in the CFU-GM number was observed in the initial phase of infection with a sublethal dose of Listeria. Treatment of mice with 0.5, 2.0 and 5.0 mg/kg MAPA for 7 days prior to infection significantly stimulated myelopoiesis in a dose-dependent manner. Moreover, treatment with 0.5 and 5.0 mg/kg MAPA resulted in 30% and 40% cures of mice lethally infected with Listeria, respectively. MAPA added directly to the culture dishes hardly affected colony formation by bone marrow cells, suggesting an indirect effect ofthis compound on myelopoiesis in vivo. In summary, the data show that MAPA can modulate the CFU-GM generation and antibacterial resistance in listeriosis. As the ability of hematopoietic tissues to produce phagocytes is of particular significance to mediate resistance to Listeria, the promotion of bone marrow CFU-GM by MAPA may contribute to a rapid restoration of phagocyte numbers in infected sites, thus mitigating the course of infection.
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Covalent Binding of BMP-2 on Surfaces Using a Self-assembled Monolayer Approach
Pohl, Theresa L. M.; Schwab, Elisabeth H.; Cavalcanti-Adam, Elisabetta A.
2013-01-01
Bone morphogenetic protein 2 (BMP-2) is a growth factor embedded in the extracellular matrix of bone tissue. BMP-2 acts as trigger of mesenchymal cell differentiation into osteoblasts, thus stimulating healing and de novo bone formation. The clinical use of recombinant human BMP-2 (rhBMP-2) in conjunction with scaffolds has raised recent controversies, based on the mode of presentation and the amount to be delivered. The protocol presented here provides a simple and efficient way to deliver BMP-2 for in vitro studies on cells. We describe how to form a self-assembled monolayer consisting of a heterobifunctional linker, and show the subsequent binding step to obtain covalent immobilization of rhBMP-2. With this approach it is possible to achieve a sustained presentation of BMP-2 while maintaining the biological activity of the protein. In fact, the surface immobilization of BMP-2 allows targeted investigations by preventing unspecific adsorption, while reducing the amount of growth factor and, most notably, hindering uncontrolled release from the surface. Both short- and long-term signaling events triggered by BMP-2 are taking place when cells are exposed to surfaces presenting covalently immobilized rhBMP-2, making this approach suitable for in vitro studies on cell responses to BMP-2 stimulation. PMID:24021994
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Dudakovic, Amel; Camilleri, Emily T.; Riester, Scott M.; Paradise, Christopher R.; Gluscevic, Martina; O'Toole, Thomas M.; Thaler, Roman; Evans, Jared M.; Yan, Huihuang; Subramaniam, Malayannan; Hawse, John R.; Stein, Gary S.; Montecino, Martin A.; McGee-Lawrence, Meghan E.; Westendorf, Jennifer J.; van Wijnen, Andre J.
2016-01-01
Perturbations in skeletal development and bone degeneration may result in reduced bone mass and quality, leading to greater fracture risk. Bone loss is mitigated by bone protective therapies, but there is a clinical need for new bone-anabolic agents. Previous work has demonstrated that Ezh2 (enhancer of zeste homolog 2), a histone 3 lysine 27 (H3K27) methyltransferase, suppressed differentiation of osteogenic progenitors. Here, we investigated whether inhibition of Ezh2 can be leveraged for bone stimulatory applications. Pharmacologic inhibition and siRNA knockdown of Ezh2 enhanced osteogenic commitment of MC3T3 preosteoblasts. Next generation RNA sequencing of mRNAs and real time quantitative PCR profiling established that Ezh2 inactivation promotes expression of bone-related gene regulators and extracellular matrix proteins. Mechanistically, enhanced gene expression was linked to decreased H3K27 trimethylation (H3K27me3) near transcriptional start sites in genome-wide sequencing of chromatin immunoprecipitations assays. Administration of an Ezh2 inhibitor modestly increases bone density parameters of adult mice. Furthermore, Ezh2 inhibition also alleviated bone loss in an estrogen-deficient mammalian model for osteoporosis. Ezh2 inhibition enhanced expression of Wnt10b and Pth1r and increased the BMP-dependent phosphorylation of Smad1/5. Thus, these data suggest that inhibition of Ezh2 promotes paracrine signaling in osteoblasts and has bone-anabolic and osteoprotective potential in adults. PMID:27758858
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Bioactive macroporous titanium implants highly interconnected.
Caparrós, Cristina; Ortiz-Hernandez, Mónica; Molmeneu, Meritxell; Punset, Miguel; Calero, José Antonio; Aparicio, Conrado; Fernández-Fairén, Mariano; Perez, Román; Gil, Francisco Javier
2016-10-01
Intervertebral implants should be designed with low load requirements, high friction coefficient and low elastic modulus in order to avoid the stress shielding effect on bone. Furthermore, the presence of a highly interconnected porous structure allows stimulating bone in-growth and enhancing implant-bone fixation. The aim of this study was to obtain bioactive porous titanium implants with highly interconnected pores with a total porosity of approximately 57 %. Porous Titanium implants were produced by powder sintering route using the space holder technique with a binder phase and were then evaluated in an in vivo study. The size of the interconnection diameter between the macropores was about 210 μm in order to guarantee bone in-growth through osteblastic cell penetration. Surface roughness and mechanical properties were analyzed. Stiffness was reduced as a result of the powder sintering technique which allowed the formation of a porous network. Compression and fatigue tests exhibited suitable properties in order to guarantee a proper compromise between mechanical properties and pore interconnectivity. Bioactivity treatment effect in novel sintered porous titanium materials was studied by thermo-chemical treatments and were compared with the same material that had undergone different bioactive treatments. Bioactive thermo-chemical treatment was confirmed by the presence of sodium titanates on the surface of the implants as well as inside the porous network. Raman spectroscopy results suggested that the identified titanate structures would enhance in vivo apatite formation by promoting ion exchange for the apatite formation process. In vivo results demonstrated that the bioactive titanium achieved over 75 % tissue colonization compared to the 40 % value for the untreated titanium.
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Bone up: craniomandibular development and hard-tissue biomineralization in neonate mice.
Thompson, Khari D; Weiss-Bilka, Holly E; McGough, Elizabeth B; Ravosa, Matthew J
2017-10-01
The presence of regional variation in the osteogenic abilities of cranial bones underscores the fact that the mechanobiology of the mammalian skull is more complex than previously recognized. However, the relationship between patterns of cranial bone formation and biomineralization remains incompletely understood. In four strains of mice, micro-computed tomography was used to measure tissue mineral density during perinatal development in three skull regions (calvarium, basicranium, mandible) noted for variation in loading environment, embryological origin, and ossification mode. Biomineralization levels increased during perinatal ontogeny in the mandible and calvarium, but did not increase in the basicranium. Tissue mineral density levels also varied intracranially, with density in the mandible being highest, in the basicranium intermediate, and in the calvarium lowest. Perinatal increases in, and elevated levels of, mandibular biomineralization appear related to the impending postweaning need to resist elevated masticatory stresses. Similarly, perinatal increases in calvarial biomineralization may be linked to ongoing brain expansion, which is known to stimulate sutural bone formation in this region. The lack of perinatal increase in basicranial biomineralization could be a result of earlier developmental maturity in the cranial base relative to other skull regions due to its role in supporting the brain's mass throughout ontogeny. These results suggest that biomineralization levels and age-related trajectories throughout the skull are influenced by the functional environment and ontogenetic processes affecting each region, e.g., onset of masticatory loads in the mandible, whereas variation in embryology and ossification mode may only have secondary effects on patterns of biomineralization. Knowledge of perinatal variation in tissue mineral density, and of normal cranial bone formation early in development, may benefit clinical therapies aiming to correct developmental defects and traumatic injuries in the skull, and more generally characterize loading environments and skeletal adaptations in mammals by highlighting the need for multi-level analyses for evaluating functional performance of cranial bone. Copyright © 2017 Elsevier GmbH. All rights reserved.
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Hoemann, C D; Sun, J; McKee, M D; Chevrier, A; Rossomacha, E; Rivard, G-E; Hurtig, M; Buschmann, M D
2007-01-01
We have previously shown that microfractured ovine defects are repaired with more hyaline cartilage when the defect is treated with in situ-solidified implants of chitosan-glycerol phosphate (chitosan-GP) mixed with autologous whole blood. The objectives of this study were (1) to characterize chitosan-GP/blood clots in vitro, and (2) to develop a rabbit marrow stimulation model in order to determine the effects of the chitosan-GP/blood implant and of debridement on the formation of incipient cartilage repair tissue. Blood clots were characterized by histology and in vitro clot retraction tests. Bilateral 3.5 x 4 mm trochlear defects debrided into the calcified layer were pierced with four microdrill holes and filled with a chitosan-GP/blood implant or allowed to bleed freely as a control. At 1 day post-surgery, initial defects were characterized by histomorphometry (n=3). After 8 weeks of repair, osteochondral repair tissues between or through the drill holes were evaluated by histology, histomorphometry, collagen type II expression, and stereology (n=16). Chitosan-GP solutions structurally stabilized the blood clots by inhibiting clot retraction. Treatment of drilled defects with chitosan-GP/blood clots led to the formation of a more integrated and hyaline repair tissue above a more porous and vascularized subchondral bone plate compared to drilling alone. Correlation analysis of repair tissue between the drill holes revealed that the absence of calcified cartilage and the presence of a porous subchondral bone plate were predictors of greater repair tissue integration with subchondral bone (P<0.005), and of a higher total O'Driscoll score (P<0.005 and P<0.01, respectively). Chitosan-GP/blood implants applied in conjunction with drilling, compared to drilling alone, elicited a more hyaline and integrated repair tissue associated with a porous subchondral bone replete with blood vessels. Concomitant regeneration of a vascularized bone plate during cartilage repair could provide progenitors, anabolic factors and nutrients that aid in the formation of hyaline cartilage.
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Somjen, D; Katzburg, S; Sharon, O; Grafi-Cohen, M; Knoll, E; Stern, N
2011-02-01
In cultured human osteoblasts estradiol-17β (E2) modulated DNA synthesis, the specific activity of creatine kinase BB (CK), 12 and 15 lipoxygenase (LO) mRNA expression and formation of 12- and 15-hydroxyeicosatetraenoic acid (HETE). We now investigate the response of human bone cell line (SaOS2) to phytoestrogens and estrogen receptors (ER)-specific agonists and antagonists. Treatment of SaSO2 with E2, 2,3-bis (4-hydroxyphenyl)-propionitrile (DPN; ERβ-specific agonist), 4,4',4″-[4-propyl-(1H)-pyrazol-1,3,5-triyl] tris-phenol (PPT; ERα-specific agonist), biochainin A (BA), daidzein (D), genistein (G) and raloxifene (Ral) showed increased DNA synthesis and CK. Ral inhibited completely all stimulations except DPN and to some extent D. The ERα-specific antagonist methyl-piperidino-pyrazole (MPP) and the ERβ-specific antagonist 4-[2-phenyl-5,7-bis (tri-fluoro-methyl) pyrazolo [1,5-a]pyrimidin-3-yl] phenol (PTHPP) inhibited DNA synthesis, CK and reactive oxygen species (ROS) formation induced by estrogens according to their receptors affinity. The LO inhibitor baicaleine inhibited only E2, DPN and G's effects. E2 and Ral unlike all other compounds had no effect on ERα mRNA expression, while ERβ mRNA expression was stimulated by all compounds. All compounds modulated the expression of 12LO and 15LO mRNA, except E2, PPT and Ral for 12LO, and 12- and 15-HETE productions and stimulated ROS formation which was inhibited by NADPH oxidase inhibitors diphenyleneiodonium chloride (DPI) and N-acetyl cysteine and the estrogen inhibitor ICI. DPI did not affect hormonal-induced DNA and CK. In conclusion, we provide evidence for the separation of mediation via ERα and ERβ pathways in the effects of estrogenic compounds on osteoblasts, but the role of LO/HETE/ROS is unclear. Copyright © 2010 Wiley-Liss, Inc.
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NASA Technical Reports Server (NTRS)
Ke, Hua Zhu; Jee, Webster S.S.; Zeng, Qing Qiang; Li, Mei; Lin, Bai Yun
1993-01-01
To investigate the effects of ovariectomy and the simultaneous administration of prostaglandin E2 (PGE2) on rat tibial shaft cortical bone histomorphometry, thirty-five 3 month-old female Sprague-Dawley rats were either ovariectomized (OVX), or sham ovariectomy (sham-OVX). The OVX rats were divided into three groups and treated with 0, 1 and 6 mg PGE2/kg/day for 90 days. The double fluorescent labeled undecalcified tibial shaft cross sections (proximal to the tibiofibular junction) of all the subjects were used for histomorphometry analysis. No differences in cross-sectional area and cortical bone area were found between sham-OVX and OVX controls, but OVX increased marrow area, intracortical porosity area and endocortical eroded perimeter. Periosteal and endocortical bone formation rates decreased with aging yet OVX prevented these changes. These OVX-induced increases in marrow area and endocortical eroded perimeter were prevented by 1 mg PGE2/kg/day treatment and added bone to periosteal and endocortical surfaces and to the marrow cavity. At the 6 mg/kg/day dose level, PGE2-treated OVX rats increased total tissue area, cortical bone area, marrow trabmular bone area, minimal cortical width and intracortical porosity area, and decreased marrow area compared to basal, sham-OVX and OVX controls. In addition, periosteal bone formation was elevated in the 6 mg PGE2/kg/day-treated OVX rats compared to OVX controls. Endocortical eroded perimeter increased from basal and sham-OVX control levels, but decreased from OVX control levels in the 6 mg PGE2/kg/day-treated OVX rats. Our study confirmed that ovariectomy does not cause osteopenia in tibial shaft cortical bone in rats, but it does stimulate endocortical bone resorption and enlarges marrow area. The new findings from the present study demonstrate that PGE2 prevents the OVX-induced increases in endocortical bone resorption and marrow area and adds additional bone to periosteal and endocortical surfaces and to marrow cavity to increase total bone mass in the tibial shaft of OVX rats when given immediately following ovafiectomy.
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Gronowicz, Gloria; Jacobs, Emily; Peng, Tao; Zhu, Li; Hurley, Marja; Kuhn, Liisa T
2017-12-01
A drug delivery coating for synthetic bone grafts has been developed to provide sequential delivery of multiple osteoinductive factors to better mimic aspects of the natural regenerative process. The coating is composed of a biomimetic calcium phosphate (bCaP) layer that is applied to a synthetic bone graft and then covered with a poly-l-Lysine/poly-l-Glutamic acid polyelectrolyte multilayer (PEM) film. Bone morphogenetic protein-2 (BMP-2) was applied before the coating process directly on the synthetic bone graft and then, bCaP-PEM was deposited followed by adsorption of fibroblast growth factor-2 (FGF-2) into the PEM layer. Cells access the FGF-2 immediately, while the bCaP-PEM temporally delays the cell access to BMP-2. In vitro studies with cells derived from mouse calvarial bones demonstrated that Sca-1 and CD-166 positive osteoblast progenitor cells proliferated in response to media dosing with FGF-2. Coated scaffolds with BMP-2 and FGF-2 were implanted in mouse calvarial bone defects and harvested at 1 and 3 weeks. After 1 week in vivo, proliferation of cells, including Sca-1+ progenitors, was observed with low dose FGF-2 and BMP-2 compared to BMP-2 alone, indicating that in vivo delivery of FGF-2 activated a similar population of cells as shown by in vitro testing. At 3 weeks, FGF-2 and BMP-2 delivery increased bone formation more than BMP-2 alone, particularly in the center of the defect, confirming that the proliferation of the Sca-1 positive osteoprogenitors by FGF-2 was associated with increased bone healing. Areas of bone mineralization were positive for double fluorochrome labeling of calcium and alkaline phosphatase staining of osteoblasts, along with increased TRAP+ osteoclasts, demonstrating active bone formation distinct from the bone-like collagen/hydroxyapatite scaffold. In conclusion, the addition of a bCaP layer to PEM delayed access to BMP-2 and allowed the FGF-2 stimulated progenitors to populate the scaffold before differentiating in response to BMP-2, leading to improved bone defect healing.
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Watanabe, Yusuke; Namba, Aki; Aida, Yukiko; Honda, Kazuhiro; Tanaka, Hideki; Suzuki, Naoto; Matsumura, Hideo; Maeno, Masao
2009-01-01
Elevated interleukin (IL)-1 concentrations in synovial fluid have been implicated in joint bone and cartilage destruction. Previously, we showed that IL-1beta stimulated the expression of prostaglandin (PG) receptor EP4 via increased PGE(2) production. However, the effect of IL-1beta on osteoclast formation via chondrocytes is unclear. Therefore, we examined the effect of IL-1beta and/or celecoxib on the expression of macrophage colony-stimulating factor (M-CSF), receptor activator of NF-kappaB ligand (RANKL), and osteoprotegerin (OPG) in human chondrocytes, and the indirect effect of IL-1beta on osteoclast-like cell formation using RAW264.7 cells. OPG and RANKL expression increased with IL-1beta; whereas M-CSF expression decreased. Celecoxib blocked the stimulatory effect of IL-1beta. Conditioned medium from IL-1beta-treated chondrocytes decreased TRAP staining in RAW264.7 cells. These results suggest that IL-1beta suppresses the formation of osteoclast-like cells via increased OPG production and decreased M-CSF production in chondrocytes, and OPG production may increase through an autocrine mechanism involving celecoxib-related PGs.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Kulkarni, Rishikesh N.; Bakker, Astrid D.; Everts, Vincent
Highlights: Black-Right-Pointing-Pointer Osteocyte incubation with IL-1{beta} stimulated osteocyte-modulated osteoclastogenesis. Black-Right-Pointing-Pointer Conditioned medium from IL-1{beta}-treated osteocytes increased osteoclastogenesis. Black-Right-Pointing-Pointer IL-1{beta} upregulated RANKL and downregulated OPG gene expression by osteocytes. Black-Right-Pointing-Pointer CYR61 is upregulated in mechanically stimulated osteocytes. Black-Right-Pointing-Pointer Mechanical loading of osteocytes may abolish IL-1{beta}-induced osteoclastogenesis. -- Abstract: Inflammatory diseases such as rheumatoid arthritis are often accompanied by higher plasma and synovial fluid levels of interleukin-1{beta} (IL-1{beta}), and by increased bone resorption. Since osteocytes are known to regulate bone resorption in response to changes in mechanical stimuli, we investigated whether IL-1{beta} affects osteocyte-modulated osteoclastogenesis in the presence or absence of mechanicalmore » loading of osteocytes. MLO-Y4 osteocytes were pre-incubated with IL-1{beta} (0.1-1 ng/ml) for 24 h. Cells were either or not subjected to mechanical loading by 1 h pulsating fluid flow (PFF; 0.7 {+-} 0.3 Pa, 5 Hz) in the presence of IL-1{beta} (0.1-1 ng/ml). Conditioned medium was collected after 1 h PFF or static cultures. Subsequently mouse bone marrow cells were seeded on top of the IL-1{beta}-treated osteocytes to determine osteoclastogenesis. Conditioned medium from mechanically loaded or static IL-1{beta}-treated osteocytes was added to co-cultures of untreated osteocytes and mouse bone marrow cells. Gene expression of cysteine-rich protein 61 (CYR61/CCN1), receptor activator of nuclear factor kappa-B ligand (RANKL), and osteoprotegerin (OPG) by osteocytes was determined immediately after PFF. Incubation of osteocytes with IL-1{beta}, as well as conditioned medium from static IL-1{beta}-treated osteocytes increased the formation of osteoclasts. However, conditioned medium from mechanically loaded IL-1{beta}-treated osteocytes prevented osteoclast formation. Incubation with IL-1{beta} upregulated RANKL and downregulated OPG gene expression by static osteocytes. PFF upregulated CYR61, RANKL, and OPG gene expression by osteocytes. Our results suggest that IL-1{beta} increases osteocyte-modulated osteoclastogenesis, and that mechanical loading of osteocytes may abolish IL-1{beta}-induced osteoclastogenesis.« less
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Liu, Yanzhi; Cui, Yang; Chen, Yan; Gao, Xiang; Su, Yanjie; Cui, Liao
2015-01-01
To investigate the long-term effects of three antiarthritics, namely dexamethasone, celecoxib, and methotrexate on the histology and metabolism of intact bone tissue in rats. Thirty-two 12-week-old healthy female Sprague Dawley rats were randomly allocated into four groups: 1) control (saline, daily); 2) dexamethasone (2 mg/kg, twice weekly); 3) celecoxib (50 mg/kg, daily); and 4) methotrexate (0.5 mg/kg, twice weekly). The drugs were administered to the rats for 12 weeks and the animals were weighed on a weekly basis. The femurs and lumbar vertebrae were harvested for bone mineral density and bone mechanical properties analyses. The proximal tibiae were processed for bone histomorphometry and micro-computed tomography analyses. The following results were obtained: 1) dexamethasone strongly inhibited bone formation rate accompanied with a decrease in bone mineral density and bone biomechanical properties; 2) celecoxib stimulated bone resorption, leading to a decrease of bone mass and femur biomechanic properties; and 3) methotrexate caused bone loss and bone quality deterioration to a lesser extent due to the increase of the bone turnover rate on the proximal tibial metaphysis of the rats. This study provides a comparative profile of the long-term effects of clinical doses of celecoxib, methotrexate, and dexamethasone on intact skeletons of the rats. The results indicate that the three antiarthritics have varying degrees of side effects on bone metabolism, and these findings will help physicians to learn more about the potential effects of antiarthritics on bone metabolism.
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Alpinia officinarum Stimulates Osteoblast Mineralization and Inhibits Osteoclast Differentiation.
Shim, Ki-Shuk; Lee, Chung-Jo; Yim, Nam-Hui; Gu, Min Jung; Ma, Jin Yeul
2016-01-01
Alpinia officinarum rhizome has been used as a traditional herbal remedy to treat inflammatory and internal diseases. Based on the previously observed inhibitory effect of A. officinarum rhizome in an arthritis model, we evaluated whether a water extract of A. officinarum rhizome (WEAO) would enhance in vitro osteoblast mineralization using calvarial osteoblast precursor cells or would inhibit in vitro osteoclast differentiation and bone resorption using bone marrow derived macrophages. In osteoblasts, WEAO enhanced the mRNA levels of transcription factor (runt-related transcription factor 2, smad1, smad5, and junB) and marker (bone morphogenetic protein-2, collagen type 1alpha1, and osteocalcin) genes related to osteoblast mineralization, consistent with increased alizarin red S staining intensity. WEAO markedly inhibited osteoclast differentiation by suppressing the receptor activator for nuclear factor-[Formula: see text]B ligand-induced downregulation of inhibitor of DNA binding 2 and V-maf musculoaponeurotic fibrosarcoma oncogene homolog B and the phosphorylation of c-Jun N-terminal kinase, p38, nuclear factor-[Formula: see text]B, c-Src, and Bruton's tyrosine kinase to induce nuclear factor of activated T cells cytoplasmic 1 expression. WEAO also suppressed the resorbing activity of mature osteoclasts by altering actin ring formation. Therefore, the results of this study demonstrate that WEAO stimulates osteoblast mineralization and inhibits osteoclast differentiation. Thus, WEAO may be a promising herbal candidate to treat or prevent pathological bone diseases by regulating the balance between osteoclast and osteoblast activity.
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Effect of Granulocyte-Colony Stimulating Factor on Endothelial Cells and Osteoblasts
Liu, Xi Ling; Hu, Xiang; Cai, Wei Xin; Lu, Weijia William; Zheng, Li Wu
2016-01-01
Objectives. Some animal studies showed that granulocyte-colony stimulating factor (G-CSF) provides beneficial environment for bone healing. It has been well documented that endothelial cells and osteoblasts play critical roles in multiple phases of bone healing. However, the biological effects of G-CSF on these cells remain controversial. This study aimed to investigate the influence of G-CSF at various concentrations on endothelial cells and osteoblasts. Materials and Methods. Human umbilical vein endothelial cells (HUVECs) and human osteoblasts (hOBs) were treated with G-CSF at 1000, 100, 10, and 0 ng/mL, respectively. The capacity of cell proliferation, migration, and tube formation of HUVECs was evaluated at 72, 8, and 6 hours after treatment, respectively. The capacity of proliferation, differentiation, and mineralization of hOBs was evaluated at 24 hours, 72 hours, and 21 days after treatment, respectively. Results. HUVECs treated with 100 and 1000 ng/mL G-CSF showed a significantly higher value comparing with controls in migration assay (p < 0.001, p < 0.01, resp.); the group treated with 1000 ng/mL G-CSF showed a significantly lower value on tube formation. No significant difference was detected in groups of hOBs. Conclusions. G-CSF showed favorable effects only on the migration of HUVECs, and no direct influence was found on hOBs. PMID:27006951
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NASA Astrophysics Data System (ADS)
Baker, Kevin C.
Numerous clinical situations necessitate the use of bone graft materials to enhance bone formation. While autologous and allogenic materials are considered the gold standards in the setting of fracture healing and spine fusion, their disadvantages, which include donor site morbidity and finite supply have stimulated research and development of novel bone graft substitute materials. Among the most promising candidate materials are resorbable polymers, composed of lactic and/or glycolic acid. While the characteristics of these materials, such as predictable degradation kinetics and biocompatibility, make them an excellent choice for bone graft substitute applications, they lack mechanical strength when synthesized with the requisite porous morphology. As such, porous resorbable polymers are often reinforced with filler materials. In the presented work, we describe the use of supercritical carbon dioxide (scCO2) processing to create porous resorbable polymeric constructs reinforced by nanostructured, organically modified Montmorillonite clay (nanoclay). scCO2 processing simultaneously disperses the nanoclay throughout the polymeric matrix, while imparting a porous morphology to the construct conducive to facilitating cellular infiltration and neoangiogenesis, which are necessary components of bone growth. With the addition of as little as 2.5wt% of nanoclay, the compressive strength of the constructs nearly doubles putting them on par with human cortico-cancellous bone. Rheological measurements indicate that the dominant mode of reinforcement of the nanocomposite constructs is the restriction of polymer chain mobility. This restriction is a function of the positive interaction between polymer chains and the nanoclay. In vivo inflammation studies indicate biocompatibility of the constructs. Ectopic osteogenesis assays have determined that the scCO2-processed nanocomposites are capable of supporting growth-factor induced bone formation. scCO 2-processed resorbable polymer nanocomposites composed of resorbable polymers and nanocaly exhibit physical, mechanical and biologic properties that make them excellent candidate materials for structural bone graft substitute applications.
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Tencerova, Michaela; Figeac, Florence; Ditzel, Nicholas; Taipaleenmäki, Hanna; Nielsen, Tina Kamilla; Kassem, Moustapha
2018-06-01
Obesity represents a risk factor for development of insulin resistance and type 2 diabetes. In addition, it has been associated with increased adipocyte formation in the bone marrow (BM) along with increased risk for bone fragility fractures. However, little is known on the cellular mechanisms that link obesity, BM adiposity, and bone fragility. Thus, in an obesity intervention study in C57BL/6J mice fed with a high-fat diet (HFD) for 12 weeks, we investigated the molecular and cellular phenotype of bone marrow adipose tissue (BMAT), BM progenitor cells, and BM microenvironment in comparison to peripheral adipose tissue (AT). HFD decreased trabecular bone mass by 29%, cortical thickness by 5%, and increased BM adiposity by 184%. In contrast to peripheral AT, BMAT did not exhibit pro-inflammatory phenotype. BM progenitor cells isolated from HFD mice exhibited decreased mRNA levels of inflammatory genes (Tnfα, IL1β, Lcn2) and did not manifest an insulin resistant phenotype evidenced by normal levels of pAKT after insulin stimulation as well as normal levels of insulin signaling genes. In addition, BM progenitor cells manifested enhanced adipocyte differentiation in HFD condition. Thus, our data demonstrate that BMAT expansion in response to HFD exerts a deleterious effect on the skeleton. Continuous recruitment of progenitor cells to adipogenesis leads to progenitor cell exhaustion, decreased recruitment to osteoblastic cells, and decreased bone formation. In addition, the absence of insulin resistance and inflammation in the BM suggest that BMAT buffers extra energy in the form of triglycerides and thus plays a role in whole-body energy homeostasis. © 2018 The Authors. Journal of Bone and Mineral Research Published by Wiley Periodicals, Inc. © 2018 The Authors. Journal of Bone and Mineral Research Published by Wiley Periodicals, Inc.
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Leukemia inhibitory factor: a novel bone-active cytokine.
Reid, L R; Lowe, C; Cornish, J; Skinner, S J; Hilton, D J; Willson, T A; Gearing, D P; Martin, T J
1990-03-01
A number of cytokines have been found to be potent regulators of bone resorption and to share the properties originally attributed to osteoclast-activating factor. One such activity, differentiation-inducing factor (DIF, D-factor) from mouse spleen cells, shares a number of biological and biochemical properties with the recently characterized and cloned leukemia inhibitory factor (LIF). We have assessed the effects of recombinant LIF on bone resorption and other parameters in neonatal mouse calvaria. Both recombinant murine and human (h) LIFs stimulated 45Ca release from prelabeled calvaria in a dose-dependent manner. The increase in bone resorption was associated with an increase in the number of osteoclasts per mm2 bone. The osteolytic effect of hLIF were blocked by 10(-7) M indomethacin. hLIF also stimulated incorporation of [3H] thymidine into calvaria, but the dose-response relationship was distinct from that for bone resorption, and this effect was not blocked by indomethacin. Similarly, hLIF increased [3H]phenylalanine incorporation into calvaria, and this was also not inhibited by indomethacin. It is concluded that LIF stimulates bone resorption by a mechanism involving prostaglandin production, but that a distinct mechanism is responsible for its stimulation of DNA and protein synthesis. The primary structure of LIF differs from that of other fully characterized, bone-active cytokines, and it, thus, represents a novel factor which may be involved in the normal regulation of bone cell function.
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Kim, Sae Hyun; Oh, Byung-Mo; Han, Tae Ryun; Jeong, Ho Joong
2015-01-01
Objective To identify the differences in the movement of the hyoid bone and the vocal cord with and without electrical stimulation in normal subjects. Methods Two-dimensional motion analysis using a videofluoroscopic swallowing study with and without electrical stimulation was performed. Surface electrical stimulation was applied during swallowing using electrodes placed at three different locations on each subject. All subjects were analyzed three times using the following electrode placements: with one pair of electrodes on the suprahyoid muscles and a second pair on the infrahyoid muscles (SI); with placement of the electrode pairs on only the infrahyoid muscles (IO); and with the electrode pairs placed vertically on the suprahyoid and infrahyoid muscles (SIV). Results The main outcomes of this study demonstrated an initial downward displacement as well as different movements of the hyoid bone with the three electrode placements used for electrical stimulation. The initial positions of the hyoid bone with the SI and IO placements resulted in an inferior and anterior displaced position. During swallowing, the hyoid bone moved in a more superior and less anterior direction, resulting in almost the same peak position compared with no electrical stimulation. Conclusion These results demonstrate that electrical stimulation caused an initial depression of the hyoid bone, which had nearly the same peak position during swallowing. Electrical stimulation during swallowing was not dependent on the position of the electrode on the neck, such as on the infrahyoid or on both the suprahyoid and infrahyoid muscles. PMID:26361589
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MicroRNA Functions in Osteogenesis and Dysfunctions in Osteoporosis
van Wijnen, Andre J.; van de Peppel, Jeroen; van Leeuwen, Johannes P.; Lian, Jane B.; Stein, Gary S.; Westendorf, Jennifer J.; Oursler, Merry-Jo; Sampen, Hee-Jeong Im; Taipaleenmaki, Hanna; Hesse, Eric; Riester, Scott; Kakar, Sanjeev
2013-01-01
MicroRNAs (miRNAs) are critical post-transcriptional regulators of gene expression that control osteoblast mediated bone formation and osteoclast-related bone remodelling. Deregulation of miRNA mediated mechanisms is emerging as an important pathological factor in bone degeneration (e.g., osteoporosis) and other bone-related diseases. MiRNAs are intriguing regulatory molecules that are networked with cell signaling pathways and intricate transcriptional programs through ingenuous circuits with remarkably simple logic. This overview examines key principles by which miRNAs control differentiation of osteoblasts as they evolve from mesenchymal stromal cells during osteogenesis, or of osteoclasts as they originate from monocytic precursors in the hematopoietic lineage during osteoclastogenesis. Of particular note are miRNAs that are temporally up-regulated during osteoblastogenesis (e.g., miR-218) or osteoclastogenesis (e.g., miR-148a). Each miRNA stimulates differentiation by suppressing inhibitory signalling pathways (‘double-negative’ regulation). The excitement surrounding miRNAs in bone biology stems from the prominent effects that individual miRNAs can have on biological transitions during differentiation of skeletal cells and correlations of miRNA dysfunction with bone diseases. MiRNAs have significant clinical potential which is reflected by their versatility as disease-specific biomarkers and their promise as therapeutic agents to ameliorate or reverse bone tissue degeneration. PMID:23605904
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Economic evaluation of bone stimulation modalities: A systematic review of the literature.
Button, Melissa L; Sprague, Sheila; Gharsaa, Osama; Latouche, Sandra; Bhandari, Mohit
2009-04-01
Various bone stimulation modalities are commonly used in treatment of fresh fractures and nonunions; however, the effectiveness and efficiency of these modalities remain uncertain. A systematic review of trials evaluating the clinical and economical outcomes of ultrasounds, electrical stimulation, and extracorporeal sound waves on fracture healing was conducted. We searched four electronic databases for economic evaluations that assessed bone stimulation modalities using ultrasound therapy, electrical stimulation, or extracorporeal shock waves. In addition, we searched the references and related articles of eligible studies, and a content expert was contacted. Information on the clinical and economical outcomes of patients was independently extracted by reviewers. Fourteen studies met the inclusion criteria; therefore, very limited research was found on the cost associated with treatments and the corresponding outcomes. The data available focus primarily on the efficacy of newly introduced treatment methods for bone growth, but failed to incorporate the costs of implementing such treatments. One economic analysis was identified that assessed different treatment paths using ultrasound. A total cost savings of 24-40% per patient occurred when ultrasound was used for fresh fractures and nonunions (grade C recommendation). The results suggest that the ultrasound is a viable alternative for bone stimulation; however, the impacts of the other modalities are left unknown due to the lack of research available. Methodological limitations leave the overall economic and clinical impact of these modalities uncertain. Large, prospective, randomized controlled trials that include cost-effectiveness analyses are needed to further define the clinical effectiveness and financial burden associated with bone stimulation modalities.
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Bone formation: roles of genistein and daidzein
USDA-ARS?s Scientific Manuscript database
Bone remodeling consists of a balance between bone formation by osteoblasts and bone resorption by osteoclasts. Osteoporosis is the result of increased bone resorption and decreased bone formation causing a decreased bone mass density, loss of bone microarchitecture, and an increased risk of fractu...
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Enhanced Osteogenesis by Reduced Graphene Oxide/Hydroxyapatite Nanocomposites
Lee, Jong Ho; Shin, Yong Cheol; Lee, Sang-Min; Jin, Oh Seong; Kang, Seok Hee; Hong, Suck Won; Jeong, Chang-Mo; Huh, Jung Bo; Han, Dong-Wook
2015-01-01
Recently, graphene-based nanomaterials, in the form of two dimensional substrates or three dimensional foams, have attracted considerable attention as bioactive scaffolds to promote the differentiation of various stem cells towards specific lineages. On the other hand, the potential advantages of using graphene-based hybrid composites directly as factors inducing cellular differentiation as well as tissue regeneration are unclear. This study examined whether nanocomposites of reduced graphene oxide (rGO) and hydroxyapatite (HAp) (rGO/HAp NCs) could enhance the osteogenesis of MC3T3-E1 preosteoblasts and promote new bone formation. When combined with HAp, rGO synergistically promoted the spontaneous osteodifferentiation of MC3T3-E1 cells without hindering their proliferation. This enhanced osteogenesis was corroborated from determination of alkaline phosphatase activity as early stage markers of osteodifferentiation and mineralization of calcium and phosphate as late stage markers. Immunoblot analysis showed that rGO/HAp NCs increase the expression levels of osteopontin and osteocalcin significantly. Furthermore, rGO/HAp grafts were found to significantly enhance new bone formation in full-thickness calvarial defects without inflammatory responses. These results suggest that rGO/HAp NCs can be exploited to craft a range of strategies for the development of novel dental and orthopedic bone grafts to accelerate bone regeneration because these graphene-based composite materials have potentials to stimulate osteogenesis. PMID:26685901
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Rusten, L S; Smeland, E B; Jacobsen, F W; Lien, E; Lesslauer, W; Loetscher, H; Dubois, C M; Jacobsen, S E
1994-01-01
Stem cell factor (SCF), a key regulator of hematopoiesis, potently synergizes with a number of hematopoietic growth factors. However, little is known about growth factors capable of inhibiting the actions of SCF. TNF-alpha has been shown to act as a bidirectional regulator of myeloid cell proliferation and differentiation. This study was designed to examine interactions between TNF-alpha and SCF. Here, we demonstrate that TNF-alpha potently and directly inhibits SCF-stimulated proliferation of CD34+ hematopoietic progenitor cells. Furthermore, TNF-alpha blocked all colony formation stimulated by SCF in combination with granulocyte colony-stimulating factor (CSF) or CSF-1. The synergistic effect of SCF observed in combination with GM-CSF or IL-3 was also inhibited by TNF-alpha, resulting in colony numbers similar to those obtained in the absence of SCF. These effects of TNF-alpha were mediated through the p55 TNF receptor, whereas little or no inhibition was signaled through the p75 TNF receptor. Finally, TNF-alpha downregulated c-kit cell-surface expression on CD34+ bone marrow cells, and this was predominantly a p55 TNF receptor-mediated event as well. Images PMID:7518828
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Lau, Y-C; Qian, X; Po, K-T; Li, L-M; Guo, X
2015-02-01
This study seeks to investigate the effect of electrical stimulation (ES) at dorsal root ganglion (DRG) on disuse bone loss in a rat model. Hindlimb unloading for 14 days resulted in significant bone loss in rat tibia while rats with ES at DRG showed a significant reduced bone loss Mechanical unloading induces osteoporosis in both human and animals. Previous studies demonstrated that electrical stimulation (ES) to dorsal root ganglion (DRG) could trigger secretion of calcitonin gene-related peptide (CGRP) which plays an important role in bone modeling and remodeling. This study seeks to investigate the effect of ES to DRG on disuse bone loss in a rat model. Twenty-four rats were randomly assigned in three experimental groups: cage control (CC), hindlimb unloading (HU), and hindlimb unloading with ES (HUES). ES was applied via implantable micro-electrical stimulators (IMES) to right DRGs at vertebral levels L4-L6 in HUES group. Hindlimb unloading for 14 days resulted in 25.9% decrease in total bone mineral content (BMC), 29.2% decrease in trabecular BMD and trabecular microarchitecture and connectivity were significantly deteriorated in the proximal tibia metaphysis in HU group, while rats with ES at DRG showed significant reduced bone loss that there was 3.8% increase in total BMC, 2.3% decrease in trabecular BMD, and significant improvement in trabecular microarchitecture. There was a concurrent enhancement of expression of CGRP in stimulated DRGs. The results confirm the effect of ES at DRG on enhancing CGRP expression and suggest potential applications of IMES for the prevention and treatment of disuse bone loss.
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Zeitooni, Mehrnaz; Mäki-Torkko, Elina; Stenfelt, Stefan
The purpose of this study is to evaluate binaural hearing ability in adults with normal hearing when bone conduction (BC) stimulation is bilaterally applied at the bone conduction hearing aid (BCHA) implant position as well as at the audiometric position on the mastoid. The results with BC stimulation are compared with bilateral air conduction (AC) stimulation through earphones. Binaural hearing ability is investigated with tests of spatial release from masking and binaural intelligibility level difference using sentence material, binaural masking level difference with tonal chirp stimulation, and precedence effect using noise stimulus. In all tests, results with bilateral BC stimulation at the BCHA position illustrate an ability to extract binaural cues similar to BC stimulation at the mastoid position. The binaural benefit is overall greater with AC stimulation than BC stimulation at both positions. The binaural benefit for BC stimulation at the mastoid and BCHA position is approximately half in terms of decibels compared with AC stimulation in the speech based tests (spatial release from masking and binaural intelligibility level difference). For binaural masking level difference, the binaural benefit for the two BC positions with chirp signal phase inversion is approximately twice the benefit with inverted phase of the noise. The precedence effect results with BC stimulation at the mastoid and BCHA position are similar for low frequency noise stimulation but differ with high-frequency noise stimulation. The results confirm that binaural hearing processing with bilateral BC stimulation at the mastoid position is also present at the BCHA implant position. This indicates the ability for binaural hearing in patients with good cochlear function when using bilateral BCHAs.
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Southmayd, Emily A; De Souza, Mary Jane
2017-02-01
Bone growth, development, and remodeling are modulated by numerous circulating hormones. Throughout the lifespan, the extent to which each of the hormones impacts bone differs. Understanding the independent and combined impact of these hormones on controlling bone remodeling allows for the development of more informed decision making regarding pharmacology, specifically the use of hormonal medication, at all ages. Endocrine control of bone health in women is largely dictated by the growth hormone (GH)/insulin-like growth factor-1 (IGF-1) axis and the hypothalamic-pituitary-ovarian (HPO) axis. Growth hormone, secreted from the pituitary gland, stimulates cells in almost every tissue to secrete IGF-1, although the majority of circulating IGF-1 is produced hepatically. Indeed, systemic IGF-1 concentrations have been found to be correlated with bone mineral density (BMD) in both pre- and post-menopausal women and is often used as a marker of bone formation. Sex steroids produced by the ovaries, namely estradiol, mediate bone resorption through binding to estrogen receptors on osteoclasts and osteoblasts. Specifically, by increasing osteoclast apoptosis and decreasing osteoblast apoptosis, adequate estrogen levels prevent excessive bone resorption, which helps to explain the rapid decline in bone mass that occurs with the menopausal decrease in estrogen production. Though there are documented correlations between endogenous estrogen concentrations and GH/IGF-1 dynamics, this relationship changes across the lifespan as sex-steroid dynamics fluctuate and, possibly, as tissue responsiveness to GH stimulation decreases. Aside from the known role of endogenous sex steroids on bone health, the impact of exogenous estrogen administration is of interest, as exogenous formulations further modulate GH and IGF-1 production. However, the effect and extent of GH and IGF-1 modulation seems to be largely dependent on age at administration and route of administration. Specifically, premenopausal women using combined oral contraceptive therapy (COC), post-menopausal women taking oral hormone therapy (HT), and both pre- and post-menopausal women using a transdermal form of estrogen therapy (COC or HT) demonstrate disparate GH/IGF-1 responses to exogenous estrogen. This review serves to summarize what is currently known regarding the influence of exogenous estrogen administration across the lifespan on the GH/IGF-1 axis and implications for bone health. Copyright © 2016 Elsevier Ltd. All rights reserved.
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Takahashi, Masao; Suzuki, Etsu; Oba, Shigeyoshi; Nishimatsu, Hiroaki; Kimura, Kenjiro; Nagano, Tetsuo; Nagai, Ryozo; Hirata, Yasunobu
2010-02-01
Subcutaneous adipose tissue contains a lot of stem cells [adipose-derived stem cells (ASCs)] that can differentiate into a variety of cell lineages. In this study, we isolated ASCs from Wistar rats and examined whether ASCs would efficiently differentiate into vascular endothelial cells (ECs) in vitro. We also administered ASCs in a wire injury model of rat femoral artery and examined their effects. ASCs expressed CD29 and CD90, but not CD34, suggesting that ASCs resemble bone marrow-derived mesenchymal stem cells. When induced to differentiate into ECs with endothelial growth medium (EGM), ASCs expressed Flt-1, but not Flk-1 or mature EC markers such as CD31 and vascular endothelial cadherin. ASCs produced angiopoietin-1 when they were cultured in EGM. ASCs stimulated the migration of EC, as assessed by chemotaxis assay. When ASCs that were cultured in EGM were injected in the femoral artery, the ASCs potently and significantly inhibited neointimal formation without being integrated in the endothelial layer. EGM-treated ASCs significantly suppressed neointimal formation even when they were administered from the adventitial side. ASC administration significantly promoted endothelial repair. These results suggested that although ASCs appear to have little capacity to differentiate into mature ECs, ASCs have the potential to secrete paracrine factors that stimulate endothelial repair. Our results also suggested that ASCs inhibited neointimal formation via their paracrine effect of stimulation of EC migration in situ rather than the direct integration into the endothelial layer.
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Mechanical force-induced midpalatal suture remodeling in mice.
Hou, Bo; Fukai, Naomi; Olsen, Bjorn R
2007-06-01
Mechanical stress is an important epigenetic factor for regulating skeletal remodeling, and application of force can lead to remodeling of both bone and cartilage. Chondrocytes, osteoblasts and osteoclasts all participate and interact with each other in this remodeling process. To study cellular responses to mechanical stimuli in a system that can be genetically manipulated, we used mouse midpalatal suture expansion in vivo. Six-week-old male C57BL/6 mice were subjected to palatal suture expansion by opening loops with an initial force of 0.56 N for the periods of 1, 3, 5, 7, 14 or 28 days. Periosteal cells in expanding sutures showed increased proliferation, with Ki67-positive cells representing 1.8+/-0.1% to 4.5+/-0.4% of total suture cells in control groups and 12.0+/-2.6% to 19.9+/-1.2% in experimental/expansion groups (p<0.05). Starting at day 1, cells expressing alkaline phosphatase and type I collagen were seen. New cartilage and bone formation was observed at the oral edges of the palatal bones at day 7; at the nasal edges only bone formation without cartilage appeared to occur. An increase in osteoclast numbers suggested increased bone remodeling, ranging from 60 to 160% throughout the experimental period. Decreased Saffranin O staining after day 3 suggested decreased proteoglycan content in the secondary cartilage. Micro-CT showed a significant increase in maxillary width at days 14 and 28 (from 2334+/-4 microm to 2485+/-3 microm at day 14 and from 2383+/-5 microm to 2574+/-7 microm at day 28, p<0.001). The suture width was increased at days 14 and 28, except in the oral third region at day 28 (from 48+/-5 microm to 36+/-4 microm, p<0.05). Bone volume/total volume was significantly reduced at days 14 and 28 (50.2+/-0.7% vs. 68.0+/-3.7% and 56.5+/-1.0% vs. 60.9+/-1.3%, respectively, p<0.05), indicative of increased bone marrow space. These findings demonstrate that expansion forces across the midpalatal suture promote bone resorption through activation of osteoclasts and bone and cartilage formation via increased proliferation and differentiation of periosteal cells. Mouse midpalatal suture expansion would be useful in further studies of the ability of mineralized tissues to respond to mechanical stimulation.
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Carbon Fiber Biocompatibility for Implants
Petersen, Richard
2016-01-01
Carbon fibers have multiple potential advantages in developing high-strength biomaterials with a density close to bone for better stress transfer and electrical properties that enhance tissue formation. As a breakthrough example in biomaterials, a 1.5 mm diameter bisphenol-epoxy/carbon-fiber-reinforced composite rod was compared for two weeks in a rat tibia model with a similar 1.5 mm diameter titanium-6-4 alloy screw manufactured to retain bone implants. Results showed that carbon-fiber-reinforced composite stimulated osseointegration inside the tibia bone marrow measured as percent bone area (PBA) to a great extent when compared to the titanium-6-4 alloy at statistically significant levels. PBA increased significantly with the carbon-fiber composite over the titanium-6-4 alloy for distances from the implant surfaces of 0.1 mm at 77.7% vs. 19.3% (p < 10−8) and 0.8 mm at 41.6% vs. 19.5% (p < 10−4), respectively. The review focuses on carbon fiber properties that increased PBA for enhanced implant osseointegration. Carbon fibers acting as polymer coated electrically conducting micro-biocircuits appear to provide a biocompatible semi-antioxidant property to remove damaging electron free radicals from the surrounding implant surface. Further, carbon fibers by removing excess electrons produced from the cellular mitochondrial electron transport chain during periods of hypoxia perhaps stimulate bone cell recruitment by free-radical chemotactic influences. In addition, well-studied bioorganic cell actin carbon fiber growth would appear to interface in close contact with the carbon-fiber-reinforced composite implant. Resulting subsequent actin carbon fiber/implant carbon fiber contacts then could help in discharging the electron biological overloads through electrochemical gradients to lower negative charges and lower concentration. PMID:26966555
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Yao, Shaomian; Pan, Fenghui; Wise, Gary E
2007-03-01
Tooth eruption is a localized event that requires the expression of certain molecules at precise times to regulate bone resorption and bone formation. Parathyroid hormone-related protein (PTHrP) may be one of those molecules. Although PTHrP is produced in the stellate reticulum (SR) of the tooth and exerts its effect on the adjacent dental follicle, its expression pattern in the SR is unknown. Thus, it was the objectives of this study to determine the chronology of expression of PTHrP, and then to determine its effect on vascular endothelial growth factor (VEGF) expression for osteoclastogenesis and on bone morphogenetic protein-2 (BMP-2) for bone growth. Laser capture microdissection and RT-PCR were used to determine the chronological expression of PTHrP in vivo. In vitro, dental follicle cells were incubated with PTHrP and RT-PCR was conducted to determine its effect on VEGF and BMP-2 gene expression. PTHrP was maximally expressed at day 7 postnatally in the SR with the level of expression still high at day 9. In vitro, PTHrP upregulated VEGF120 and VEGF164 expression after 4h of incubation with a maximum effect at 6h. PTHrP upregulated BMP-2 gene expression with a maximal effect at 2h. Because the secondary burst of osteoclastogenesis needed for eruption occurs around day 10, it is possible that PTHrP is stimulating this osteoclastogenesis by upregulating VEGF. Concurrently, the upregulation of BMP-2 by PTHrP may stimulate bone growth at the base of the bony crypt to promote eruption.
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Zhong, N; Xu, B; Cui, R; Xu, M; Su, J; Zhang, Z; Liu, Y; Li, L; Sheng, C; Sheng, H; Qu, S
2016-07-01
Animal studies suggested that there is an independent bone-osteocalcin-gonadal axis, except of the hypothalamic-pituitary-gonadal axis. Based on this hypothesis, the higher osteocalcin during the high bone turnover should be followed by higher testosterone formation. Yet such clinical evidence is limited. The patients with uncontrolled hyperthyroidism are proper model with high bone turnover. If this hypothesis is true, there should be high testosterone level in patients with uncontrolled hyperthyroidism. Therefore, Graves' disease patients were recruited to study the correlation between osteocalcin and testosterone. 50 male hyperthyroidism patients with Graves' disease and 50 health persons matched by age and gender were enrolled in our cross-section study. Serum markers for thyroid hormone, sex hormone and bone metabolic markers including free triiodothyronine (FT3), free thyroxine (FT4), thyroid-stimulating hormone (TSH), testosterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH) and osteocalcin (OC), C-terminal telopeptide fragments of type I collagen (CTX) were examined. The demographic parameters such as duration of disease were also collected. All data was analyzed by SPSS 20.0. High testosterone and osteocalcin level was observed in the hyperthyroidism patients (T 36.35±10.72 nmol/l and OC 46.79±26.83 ng/ml). In simple Pearson correlation, testosterone was positively associated with OC (r=0.486, P<0.001), and this positive relation still existed after adjusted for age, BMI, smoking, drinking, duration of disease, FT3, FT4, LH, FSH, CTX in multi-linear regression analysis (See Model 1-4). In male hyperthyroidism patients, osteocalcin was positively correlated with serum testosterone, which indirectly supports the hypothesis that serum osteocalcin participates in the regulation of sex hormone. © Georg Thieme Verlag KG Stuttgart · New York.
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Buchwald, Zachary S.; Yang, Chang; Nellore, Suman; Shashkova, Elena V.; Davis, Jennifer L.; Cline, Anna; Ko, Je; Novack, Deborah V.; DiPaolo, Richard; Aurora, Rajeev
2015-01-01
TNFα and IL-17 secreted by proinflammatory T-cells (TEFF) promote bone erosion by activating osteoclasts. We previously demonstrated that in addition to bone resorption, osteoclasts act as antigen presenting cells to induce FoxP3 in CD8 T-cells (TcREG). The osteoclast-induced regulatory CD8 T-cells limit bone resorption in ovariectomized mice (a murine model of postmenopausal osteoporosis). Here we show that while low-dose RANKL maximally induces TcREG via Notch signaling pathway to limit bone resorption, high-dose RANKL promotes bone resorption. In vitro, both TNFα and IL-17, cytokines that are abundant in ovariectomized animals, suppress TcREG induction by osteoclasts by repressing Notch ligand expression in osteoclasts but this effect can be counteracted by addition of RANKL. Ovariectomized mice treated with low-dose RANKL induced TcREG that suppressed bone resorption, decreased TEFF levels and increased bone formation. High dose RANKL had the expected osteolytic effect. Low dose RANKL administration in ovariectomized mice lacking CD8 T-cells was also osteolytic, confirming that TcREG mediate this bone anabolic effect. Our results show that while RANKL directly stimulates osteoclasts to resorb bone, it also controls the osteoclasts’ ability to induce regulatory T-cells, engaging an important negative feedback loop. In addition to the conceivable clinical relevance to treatment of osteoporosis, these observations have potential relevance to induction of tolerance and autoimmune diseases. PMID:25656537
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Kim, Yun-Ho; Kim, Jung-Lye; Lee, Eun-Jung; Park, Sin-Hye; Han, Seon-Young; Kang, Soon Ah; Kang, Young-Hee
2014-03-01
Osteoclastogenesis is comprised of several stage s including progenitor survival, differentiation to mononuclear preosteoclasts, cell fusion to multinuclear mature osteoclasts, and activation to osteoclasts with bone resorbing activity. Botanical antioxidants are now being increasingly investigated for their health-promoting effects on bone. This study investigated that fisetin, a flavonol found naturally in many fruits and vegetables, suppressed osteoclastogenesis by disturbing receptor activator of nuclear factor (NF)-κB ligand (RANKL)-mediated signaling pathway and demoting osteoclastogenic protein induction. Nontoxic fisetin at ≤10 μM inhibited the induction of RANK, tumor necrosis factor receptor associated factor 6 (TRAF6) and the activation of NF-κB in RANKL-stimulated RAW 264.7 macrophages. In RANKL-differentiated osteoclasts cell fusion protein of E-cadherin was induced, which was dampened by fisetin. The formation of tartrate-resistance acid phosphatase-positive multinucleated osteoclasts was suppressed by adding fisetin to RANKL-exposed macrophages. It was also found that fisetin reduced actin ring formation and gelsolin induction of osteclasts enhanced by RANKL through disturbing c-Src-proline-rich tyrosine kinase 2 signaling. Fisetin deterred preosteoclasts from the cell-cell fusion and the organization of the cytoskeleton to seal the resorbing area and to secret protons for bone resorption. Consistently, the 5 day-treatment of fisetin diminished RANKL-induced cellular expression of carbonic anhydrase II and integrin β3 concurrently with a reduction of osteoclast bone-resorbing activity. Therefore, fisetin was a natural therapeutic agent retarding osteoclast fusion and cytoskeletal organization such as actin rings and ruffled boarder, which is a property of mature osteoclasts and is required for osteoclasts to resorb bone. Copyright © 2014 Elsevier Inc. All rights reserved.
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Kitano, Victor J.; Shimada, Jun
2018-01-01
Inflammatory bone diseases, including rheumatoid arthritis, periodontitis and peri-implantitis, are associated not only with the production of inflammatory cytokines but also with local oxidative status, which is defined by intracellular reactive oxygen species (ROS). Osteoclast differentiation has been reported to be related to increased intracellular ROS levels in osteoclast lineage cells. Sudachitin, which is a polymethoxyflavone derived from Citrus sudachi, possesses antioxidant properties and regulates various functions in mammalian cells. However, the effects of sudachitin on inflammatory bone destruction and osteoclastogenesis remain unknown. In calvaria inflamed by a local lipopolysaccharide (LPS) injection, inflammation-induced bone destruction and the accompanying elevated expression of osteoclastogenesis-related genes were reduced by the co-administration of sudachitin and LPS. Moreover, sudachitin inhibited osteoclast formation in cultures of isolated osteoblasts and osteoclast precursors. However, sudachitin rather increased the expression of receptor activator of NF-κB ligand (RANKL), which is an important molecule triggering osteoclast differentiation, and the mRNA ratio of RANKL/osteoprotegerin that is a decoy receptor for RANKL, in the isolated osteoblasts, suggesting the presence of additional target cells. When osteoclast formation was induced from osteoclast precursors derived from bone marrow cells in the presence of soluble RANKL and macrophage colony-stimulating factor, sudachitin inhibited osteoclastogenesis without influencing cell viability. Consistently, the expression of osteoclast differentiation-related molecules including c-fos, NFATc1, cathepsin K and osteoclast fusion proteins such as DC-STAMP and Atp6v0d2 was reduced by sudachitin. In addition, sudachitin decreased activation of MAPKs such as Erk and JNK and the ROS production evoked by RANKL in osteoclast lineage cells. Our findings suggest that sudachitin is a useful agent for the treatment of anti-inflammatory bone destruction. PMID:29342179
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Ohyama, Yoko; Ito, Junta; Kitano, Victor J; Shimada, Jun; Hakeda, Yoshiyuki
2018-01-01
Inflammatory bone diseases, including rheumatoid arthritis, periodontitis and peri-implantitis, are associated not only with the production of inflammatory cytokines but also with local oxidative status, which is defined by intracellular reactive oxygen species (ROS). Osteoclast differentiation has been reported to be related to increased intracellular ROS levels in osteoclast lineage cells. Sudachitin, which is a polymethoxyflavone derived from Citrus sudachi, possesses antioxidant properties and regulates various functions in mammalian cells. However, the effects of sudachitin on inflammatory bone destruction and osteoclastogenesis remain unknown. In calvaria inflamed by a local lipopolysaccharide (LPS) injection, inflammation-induced bone destruction and the accompanying elevated expression of osteoclastogenesis-related genes were reduced by the co-administration of sudachitin and LPS. Moreover, sudachitin inhibited osteoclast formation in cultures of isolated osteoblasts and osteoclast precursors. However, sudachitin rather increased the expression of receptor activator of NF-κB ligand (RANKL), which is an important molecule triggering osteoclast differentiation, and the mRNA ratio of RANKL/osteoprotegerin that is a decoy receptor for RANKL, in the isolated osteoblasts, suggesting the presence of additional target cells. When osteoclast formation was induced from osteoclast precursors derived from bone marrow cells in the presence of soluble RANKL and macrophage colony-stimulating factor, sudachitin inhibited osteoclastogenesis without influencing cell viability. Consistently, the expression of osteoclast differentiation-related molecules including c-fos, NFATc1, cathepsin K and osteoclast fusion proteins such as DC-STAMP and Atp6v0d2 was reduced by sudachitin. In addition, sudachitin decreased activation of MAPKs such as Erk and JNK and the ROS production evoked by RANKL in osteoclast lineage cells. Our findings suggest that sudachitin is a useful agent for the treatment of anti-inflammatory bone destruction.
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Verheyen, Nicolas; Fahrleitner-Pammer, Astrid; Belyavskiy, Evgeny; Gruebler, Martin R; Dimai, Hans Peter; Amrein, Karin; Ablasser, Klemens; Martensen, Johann; Catena, Cristiana; Pieske-Kraigher, Elisabeth; Colantonio, Caterina; Voelkl, Jakob; Lang, Florian; Alesutan, Ioana; Meinitzer, Andreas; März, Winfried; Brussee, Helmut; Pieske, Burkert; Pilz, Stefan; Tomaschitz, Andreas
2017-01-01
Observational studies suggested a link between bone disease and left ventricular (LV) dysfunction that may be pronounced in hyperparathyroid conditions. We therefore aimed to test the hypothesis that circulating markers of bone turnover correlate with LV function in a cohort of patients with primary hyperparathyroidism (pHPT). Cross-sectional data of 155 subjects with pHPT were analyzed who participated in the "Eplerenone in Primary Hyperparathyroidism" (EPATH) Trial. Multivariate linear regression analyses with LV ejection fraction (LVEF, systolic function) or peak early transmitral filling velocity (e', diastolic function) as dependent variables and N-terminal propeptide of procollagen type 1 (P1NP), osteocalcin (OC), bone-specific alkaline phosphatase (BALP), or beta-crosslaps (CTX) as the respective independent variable were performed. Analyses were additionally adjusted for plasma parathyroid hormone, plasma calcium, age, sex, HbA1c, body mass index, mean 24-hours systolic blood pressure, smoking status, estimated glomerular filtration rate, antihypertensive treatment, osteoporosis treatment, 25-hydroxy vitamin D and N-terminal pro-brain B-type natriuretic peptide. Independent relationships were observed between P1NP and LVEF (adjusted β-coefficient = 0.201, P = 0.035) and e' (β = 0.188, P = 0.042), respectively. OC (β = 0.192, P = 0.039) and BALP (β = 0.198, P = 0.030) were each independently related with e'. CTX showed no correlations with LVEF or e'. In conclusion, high bone formation markers were independently and paradoxically related with better LV diastolic and, partly, better systolic function, in the setting of pHPT. Potentially cardio-protective properties of stimulated bone formation in the context of hyperparathyroidism should be explored in future studies.
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Qu, Bo; Xia, Xun; Yan, Ming; Gong, Kai; Deng, Shaolin; Huang, Gang; Ma, Zehui; Pan, Xianming
2015-10-15
The increased osteoclastic activity accounts for pathological bone loss in diseases including osteoporosis. MicroRNAs are widely accepted to be involved in the regulation of osteopenic diseases. Recently, the low expression of miR-218 was demonstrated in CD14(+) peripheral blood mononuclear cells (PBMCs) from patients with postmenopausal osteoporosis. However, its role and the underlying mechanism in osteoporosis are still undefined. Here, an obvious decrease in miR-218 expression was observed during osteoclastogenesis under receptor activator of nuclear factor κB ligand (RANKL) stimulation, in both osteoclast precursors of bone marrow macrophages (BMMs) and RAW 264.7. Further analysis confirmed that overexpression of miR-218 obviously attenuated the formation of multinuclear mature osteoclasts, concomitant with the decrease in Trap and Cathepsin K levels, both the master regulators of osteoclastogenesis. Moreover, miR-218 up-regulation dramatically inhibited osteoclast precursor migration, actin ring formation and bone resorption. Mechanism assay demonstrated that miR-218 overexpression attenuated the expression of p38MAPK, c-Fos and NFATc1 signaling molecules. Following preconditioning with P79350, an agonist of p38MAPK, the inhibitor effect of miR-218 on osteoclastogenesis and bone-resorbing activity was strikingly ameliorated. Together, this study revealed a crucial role of miR-218 as a negative regulator for osteoclastogenesis and bone resorption by suppressing the p38MAPK-c-Fos-NFATc1 pathway. Accordingly, this research will provide a promising therapeutic agent against osteopenic diseases including osteoporosis. Copyright © 2015 Elsevier Inc. All rights reserved.