Fibroblast growth factor 2 and cyclic AMP synergistically regulate bone sialoprotein gene expression.

PubMed

Shimizu, Emi; Nakayama, Youhei; Nakajima, Yu; Kato, Naoko; Takai, Hideki; Kim, Dong-Soon; Arai, Masato; Saito, Ryoichiro; Sodek, Jaro; Ogata, Yorimasa

2006-07-01

Bone sialoprotein (BSP) is a noncollagenous protein of the mineralized bone extracellular matrix. We here report that FGF2 and cAMP act synergistically to stimulate BSP gene expression. Treatment of ROS 17/2.8 cells with either 10 ng/ml FGF2 or 1 microM FSK for 6 h resulted in 5.4- and 8.2-fold increases, respectively, in the levels of BSP mRNA. However, in the presence of both FGF2 and forskolin (FGF/FSK), BSP mRNA levels were increased synergistically by 20.4-fold. Using a luciferase reporter construct, encompassing BSP promoter nucleotides -116 to +60, transcription was also increased synergistically by 15.0-fold with FGF/FSK, compared to stimulations of 2.6- and 5.3-fold, respectively, for FGF2 and FSK alone. Transcriptional stimulation by FGF/FSK abrogated in constructs included 2 bp mutations in the inverted CCAAT, CRE, FRE and Pit-1 elements. Whereas the FRE-protein complex was increased by FGF2 and FGF/FSK, the Pit-1-protein complex was decreased by FSK and FGF/FSK. Notably, transcriptional activity induced by FGF/FSK was blocked by protein kinase A, tyrosine kinase and MEK inhibitors. These studies indicate that the combinatorial effects of FGF and FSK act through PKA, tyrosine kinase and MAP-kinase-dependent pathways, which target the inverted CCAAT, CRE, FRE and Pit-1 elements in the BSP gene to synergistically increase BSP expression.

Colour stability of bovine Longissimus and Psoas major muscle as affected by electrical stimulation and hot boning.

PubMed

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.

Digital electronic bone growth stimulator

DOEpatents

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.

Strontium attenuates rhBMP-2-induced osteogenic differentiation via formation of Sr-rhBMP-2 complex and suppression of Smad-dependent signaling pathway.

PubMed

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.

The Molecular and Cellular Events That Take Place during Craniofacial Distraction Osteogenesis

PubMed Central

Rachmiel, Adi

2014-01-01

Summary: Gradual bone lengthening using distraction osteogenesis principles is the gold standard for the treatment of hypoplastic facial bones. However, the long treatment time is a major disadvantage of the lengthening procedures. The aim of this study is to review the current literature and summarize the cellular and molecular events occurring during membranous craniofacial distraction osteogenesis. Mechanical stimulation by distraction induces biological responses of skeletal regeneration that is accomplished by a cascade of biological processes that may include differentiation of pluripotential tissue, angiogenesis, osteogenesis, mineralization, and remodeling. There are complex interactions between bone-forming osteoblasts and other cells present within the bone microenvironment, particularly vascular endothelial cells that may be pivotal members of a complex interactive communication network in bone. Studies have implicated number of cytokines that are intimately involved in the regulation of bone synthesis and turnover. The gene regulation of numerous cytokines (transforming growth factor-β, bone morphogenetic proteins, insulin-like growth factor-1, and fibroblast growth factor-2) and extracellular matrix proteins (osteonectin, osteopontin) during distraction osteogenesis has been best characterized and discussed. Understanding the biomolecular mechanisms that mediate membranous distraction osteogenesis may guide the development of targeted strategies designed to improve distraction osteogenesis and accelerate bone regeneration that may lead to shorten the treatment duration. PMID:25289295

Extended Culture of Bone Marrow with Granulocyte Macrophage-Colony Stimulating Factor Generates Immunosuppressive Cells

PubMed Central

Na, Hye Young; Sohn, Moah; Ryu, Seul Hye; Choi, Wanho; In, Hyunju; Shin, Hyun Soo

2018-01-01

Bone marrow-derived dendritic cells (BM-DCs) are generated from bone marrow (BM) cells cultured with granulocyte macrophage-colony stimulating factor (GM-CSF) for a week. In this study we investigated the effect of duration on the BM culture with GM-CSF. Within several months, the cells in the BM culture gradually expressed homogeneous levels of CD11c and major histocompatibility complex II on surface, and they became unable to stimulate allogeneic naïve T cells in mixed lymphocyte reaction (MLR). In addition, when the BM culture were sustained for 32 wk or longer, the BM cells acquired ability to suppress the proliferation of allogeneic T cells in MLR as well as the response of ovalbumin-specific OT-I transgenic T cells in antigen-dependent manner. We found that, except for programmed death-ligand 1, most cell surface molecules were expressed lower in the BM cells cultured with GM-CSF for the extended duration. These results indicate that BM cells in the extended culture with GM-CSF undergo 2 distinct steps of functional change; first, they lose the immunostimulatory capacity; and next, they gain the immunosuppressive ability. PMID:29736292

[Issues related to secondary osteoporosis associated with growth hormone deficiency in adulthood].

PubMed

Kužma, Martin; Jackuliak, Peter; Killinger, Zdenko; Vaňuga, Peter; Payer, Juraj

Growth hormone (GH) increases linear bone growth through complex hormonal reactions, mainly mediated by insulin like growth factor 1 (IGF1) that is produced mostly by hepatocytes under influence of GH and stimulates differentiation of epiphyseal prechondrocytes. IGF1 and GH play a key role in the linear bone growth after birth and regulation of bone remodelation during the entire lifespan. It is known that adult GH deficient (GHD) patients have decreased BMD and increased risk of low-impact fractures. Most data gathered thus far on the effect of GH replacement on bone status comprise the measurement of quantitative changes of bone mass. Some animal studies with GHD showed that the bone microarchitecture, measured using computed tomography methods, is significantly compromised and improve after GH replacement. However, human studies did not show significantly decreased bone microarchitecture, but limited methodological quality does not allow firm conclusions on this subject.Key words: bone mass - bone quality - fracture - growth hormone - IGF1.

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

Digital electronic bone growth stimulator

DOEpatents

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.

[Modern condition and prospects of improvement of the specialized medical care for acute bone marrow syndrome of radiation etiology].

PubMed

Khalimov, Iu Sh; Grebeniuk, A N; Legeza, V I; Karamullin, M A; Salukhov, V V

2013-01-01

It is shown, that tactics of treatment of acute marrow failure of radiant etiology is based, first of all, on measures of supporting, replaceable and stimulating therapy. The modern means, used for prophylactic and treatment of infectious complications, are resulted. Opportunities and restrictions of transfusion of donor thrombocytes and granulocytes, erythrocytes and chilled plasma are described. Therapeutic efficiency of transplantation of a bone marrow, cells of embryonic liver and stem cells of peripheral or umbilical cord blood is analyzed. It is shown, that the greatest prospects in perfection of the specialized medical aid at acute radiation syndrome are connected to complex application of interleukin-1beta, interleukin-3, granulocyte or granulocyte/macrophage colony stimulated factor, thrombopoietin and others cytokines.

Modeling of time dependent localized flow shear stress and its impact on cellular growth within additive manufactured titanium implants

PubMed Central

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

Acemannan sponges stimulate alveolar bone, cementum and periodontal ligament regeneration in a canine class II furcation defect model.

PubMed

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.

Strategies to engineer tendon/ligament-to-bone interface: Biomaterials, cells and growth factors.

PubMed

Font Tellado, Sonia; Balmayor, Elizabeth R; Van Griensven, Martijn

2015-11-01

Integration between tendon/ligament and bone occurs through a specialized tissue interface called enthesis. The complex and heterogeneous structure of the enthesis is essential to ensure smooth mechanical stress transfer between bone and soft tissues. Following injury, the interface is not regenerated, resulting in high rupture recurrence rates. Tissue engineering is a promising strategy for the regeneration of a functional enthesis. However, the complex structural and cellular composition of the native interface makes enthesis tissue engineering particularly challenging. Thus, it is likely that a combination of biomaterials and cells stimulated with appropriate biochemical and mechanical cues will be needed. The objective of this review is to describe the current state-of-the-art, challenges and future directions in the field of enthesis tissue engineering focusing on four key parameters: (1) scaffold and biomaterials, (2) cells, (3) growth factors and (4) mechanical stimuli. Copyright © 2015 Elsevier B.V. All rights reserved.

Bone morphogenetic protein 7 (BMP-7) influences tendon-bone integration in vitro.

PubMed

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.

Strontium ranelate: a novel mode of action leading to renewed bone quality.

PubMed

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.

[Development, physiology, and cell activity of bone].

PubMed

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.

The Presence of Thyroid-Stimulation Blocking Antibody Prevents High Bone Turnover in Untreated Premenopausal Patients with Graves' Disease.

PubMed

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.

Role of Prostaglandin Pathway and Alendronate-Based Carriers to Enhance Statin-induced Bone

PubMed Central

Lee, Yeonju; Liu, Xinming; Nawshad, Ali; Marx, David B.; Wang, Dong; Reinhardt, Richard A.

2011-01-01

Objective This study investigated the role of the prostaglandin (PG) pathway in locally-applied, simvastatin-induced oral bone growth. The possibility of enhancing long-term bone augmentation with an alendronate-based carrier was initiated. Methods Mandibles of 44 mature female rats were treated bilaterally with the following combinations: 2 mg simvastatin in ethanol (SIM-EtOH), EtOH, 2 mg simvastatin acid complexed with alendronate-beta-cyclodextrin conjugate (SIM/ALN-CD), ALN-CD, or ALN. Bone wash technology (injection of PBS and recollection by suction) was used to sample injection sites at baseline (day 0), and 3, 7, 14 and 21 days post-treatment. After 21-24 or 48 days, histomorphometric analysis was done. The amount of PGE2 in bone wash fluid was measured by ELISA, normalized by total protein, and compared between high and low bone growth groups (ANOVA) and correlated with subsequent bone histology at 21 days (Spearman). SIM-stimulated PGE2 synthase and EP4 receptor mRNA in murine osteoblast and fibroblast cell lines were evaluated with real-time PCR. Results Single injections of 2 mg SIM-EtOH induced significantly more new bone than control side after 21 days. PGE2/protein ratios peaked at day 7 and were correlated with the subsequent 21-day new bone width. The correlations at day 14 between PGE2 and new bone width changed to a negative relationship in the test group. SIM-stimulated osteoblasts expressed increased mRNA levels of PGE receptor EP4, while SIM activated PGE synthesis in fibroblasts. SIM/ALN-CD tended to preserve bone long-term. Conclusion Findings suggest that PGE pathway activation and higher levels of PGE2 during the first week following SIM-induced bone growth are desirable, and alendronate-beta-cyclodextrin conjugates not only act as tissue-specific carriers, but preserve new bone. PMID:21438610

Healing in the new millennium: bone stimulators: an overview of where we've been and where we may be heading.

PubMed

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.

Modeling of time dependent localized flow shear stress and its impact on cellular growth within additive manufactured titanium implants.

PubMed

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.

Compact biomedical pulsed signal generator for bone tissue stimulation

DOEpatents

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.

Compact biomedical pulsed signal generator for bone tissue stimulation

DOEpatents

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.

Does hearing in response to soft-tissue stimulation involve skull vibrations? A within-subject comparison between skull vibration magnitudes and hearing thresholds.

PubMed

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.

The impact of thyroid diseases on bone metabolism and fracture risk.

PubMed

Amashukeli, M; Giorgadze, E; Tsagareli, M; Nozadze, N; Jeiranashvili, N

2010-01-01

Osteoporosis is a systemic skeletal disease characterized by low bone mass and microarchitectural deterioration of bone tissue, leading to enhanced bone fragility and a consequent increase in fracture risk. One of the leading causes of secondary osteoporosis are thyroid diseases; this fact carries special importance for Georgia because of thyroid disease prevalence in Georgian population. In the present article we discuss the mechanisms, by which thyroid hormones and thyroid stimulating hormone (TSH) act on bone. We also present the data of meta-analysis of large studies, which demonstrate the complex relationship between the thyroid diseases and bone mineral density as well as the fracture risk; namely by overt and subclinical thyrotoxicosis, hypothyroidism and the treatment with the suppressive doses of levothyroxine. Beside that, we review the related data and the possible reasons, why different treatment regimens of Grave's disease: conservative, operative and radioiodine are related to different fracture risks. Finally, we discuss briefly the practical aspects of the treatment of secondary osteoporosis, related with thyroid diseases.

Early mechanical stimulation only permits timely bone healing in sheep.

PubMed

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.

Union rate of tibiotalocalcaneal nails with internal or external bone stimulation.

PubMed

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.

The role of electromagnetic stimulation in the management of established non-union of long bone fractures: what is the evidence?

PubMed

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.

Synergistic effect of defined artificial extracellular matrices and pulsed electric fields on osteogenic differentiation of human MSCs.

PubMed

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.

A histopathologic investigation on the effects of electrical stimulation on periodontal tissue regeneration in experimental bony defects in dogs.

PubMed

Kaynak, Deniz; Meffert, Roland; Günhan, Meral; Günhan, Omer

2005-12-01

One endpoint of periodontal therapy is to regenerate the structure lost due to periodontal disease. In the periodontium, gingival epithelium is regenerated by oral epithelium. Underlying connective tissue, periodontal ligament, bone, and cementum are derived from connective tissue. Primitive connective tissue cells may develop into osteoblasts and cementoblasts, which form bone and cementum. Several procedural advances may support these regenerations; however, the regeneration of alveolar bone does not always occur. Therefore, bone stimulating factors are a main topic for periodontal reconstructive research. The present study was designed to examine histopathologically whether the application of an electrical field could demonstrate enhanced alveolar and cementum regeneration and modify tissue factors. Seven beagle dogs were used for this experiment. Mandibular left and right sides served as control and experimental sides, respectively, and 4-walled intrabony defects were created bilaterally between the third and fourth premolars. The experimental side was treated with a capacitively coupled electrical field (CCEF) (sinusoidal wave, 60 kHz, and 5 V peak-to-peak), applied for 14 hours per day. The following measurements were performed on the microphotographs: 1) the distance from the cemento-enamel junction to the apical notch (CEJ-AN) and from the crest of newly formed bone (alveolar ridge) to the apical notch (AR-AN); 2) the thickness of new cementum in the apical notch region; and 3) the length of junctional epithelium. The following histopathologic parameters were assessed by a semiquantitative subjective method: 1) inflammatory cell infiltration (ICI); 2) cellular activity of the periodontal ligament; 3) number and morphology of osteoclasts; 4) resorption lacunae; and 5) osteoblastic activity. The results showed that the quantity of new bone fill and the mean value of the thickness of the cementum were significantly higher for the experimental side (P < 0.01). The location of the base of the pocket was positioned more coronally with respect to the apical point of the coronal notch in the experimental side (statistically significant P < 0.01). The length of the junctional epithelium and the number of osteoclasts were higher in the stimulated side than the coronal side; these findings were also statistically significant (P < 0.01). The comparison of the electrically stimulated versus non-stimulated mandibles with the semiquantitative subjective method demonstrated statistically significant differences in defined histopathologic parameters, except for osteoclast morphologies (P > 0.05). This study demonstrated that the CCEF method has the potential to produce reconstructive effects and bone deposits. Further investigations with respect to the theoretical determination of local field parameters of the periodontal tissue complex, such as permittivity, conductivity, strength of the field electrical stimulation applied to the periodontal field current density, wavelength, and signal frequency appropriate for this field, should be undertaken. Using different electromotive forces alone or in combination with bone graft materials, guided tissue regeneration techniques, and dental implants may achieve a new dimension in periodontal therapy in the near future.

Bone Marrow Aspirate Concentrate-Enhanced Marrow Stimulation of Chondral Defects

PubMed Central

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

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.

Cardiotonic agent milrinone stimulates resorption in rodent bone organ culture.

PubMed Central

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

Pulsed electromagnetic fields preserve bone architecture and mechanical properties and stimulate porous implant osseointegration by promoting bone anabolism in type 1 diabetic rabbits.

PubMed

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.

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.

Androgens and bone health.

PubMed

Hansen, K A; Tho, S P

1998-01-01

Osteoporosis is one of the most common metabolic bone diseases in the adult population and its prevalence will continue to rise as our population grows older. In both sexes, hypogonadism is associated with accelerated loss of bone and development of osteoporosis. Adrenal and gonadal androgen levels decline with advancing age in both sexes. Androgens act by either directly binding to androgen receptors, or by aromatization of androgens to estrogens and subsequently interacting with estrogen receptors. Both pathways are important for skeletal health. Direct androgen binding to an androgen receptor may play a more important role in early skeletal development and determination of sexual dimorphic traits. While bone remodeling, which is important in maintaining healthy bone through life, is primarily stimulated by estrogen, studies in the rat and human support the complex action of androgens and estrogens in bone modeling and remodeling, and hence the development and maintenance of healthy bone. In postmenopausal females, the addition of androgens to hormone replacement therapy results in significant additional improvement in bone mineral density compared to estrogen replacement alone. Accumulating evidence indicate that androgens play an important role in the health of bone and the potential benefit of adding these agents to hormone replacement regimens.

Mechanical Signaling for Bone Modeling and Remodeling

PubMed Central

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

Testosterone Combined with Electrical Stimulation and Standing: Effect on Muscle and Bone

DTIC Science & Technology

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

Finite Element Modelling of the Femur Bone of a Subject Suffering from Motor Neuron Lesion Subjected to Electrical Stimulation.

PubMed

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.

Microfluidic co-culture platform for investigating osteocyte-osteoclast signalling during fluid shear stress mechanostimulation.

PubMed

Middleton, K; Al-Dujaili, S; Mei, X; Günther, A; You, L

2017-07-05

Bone cells exist in a complex environment where they are constantly exposed to numerous dynamic biochemical and mechanical stimuli. These stimuli regulate bone cells that are involved in various bone disorders, such as osteoporosis. Knowledge of how these stimuli affect bone cells have been utilised to develop various treatments, such as pharmaceuticals, hormone therapy, and exercise. To investigate the role that bone loading has on these disorders in vitro, bone cell mechanotransduction studies are typically performed using parallel plate flow chambers (PPFC). However, these chambers do not allow for dynamic cellular interactions among different cell populations to be investigated. We present a microfluidic approach that exposes different cell populations, which are located at physiologically relevant distances within adjacent channels, to different levels of fluid shear stress, and promotes cell-cell communication between the different channels. We employed this microfluidic system to assess mechanically regulated osteocyte-osteoclast communication. Osteoclast precursors (RAW264.7 cells) responded to cytokine gradients (e.g., RANKL, OPG, PGE-2) developed by both mechanically stimulated (fOCY) and unstimulated (nOCY) osteocyte-like MLO-Y4 cells simultaneously. Specifically, we observed increased osteoclast precursor cell densities and osteoclast differentiation towards nOCY. We also used this system to show an increased mechanoresponse of osteocytes when in co-culture with osteoclasts. We envision broad applicability of the presented approach for microfluidic perfusion co-culture of multiple cell types in the presence of fluid flow stimulation, and as a tool to investigate osteocyte mechanotransduction, as well as bone metastasis extravasation. This system could also be applied to any multi-cell population cross-talk studies that are typically performed using PPFCs (e.g. endothelial cells, smooth muscle cells, and fibroblasts). Copyright © 2017 Elsevier Ltd. All rights reserved.

Bone Augmentation in Rabbit Tibia Using Microfixed Cobalt-Chromium Membranes with Whole Blood and Platelet-Rich Plasma.

PubMed

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.

Nanotechnology for Stimulating Osteoprogenitor Differentiation

PubMed Central

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

Implantable electrical bone stimulation for arthrodeses of the foot and ankle in high-risk patients: a multicenter study.

PubMed

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.

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.

IFN-γ stimulates osteoclast formation and bone loss in vivo via antigen-driven T cell activation

PubMed Central

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

Computational modelling of the mechanics of trabecular bone and marrow using fluid structure interaction techniques.

PubMed

Birmingham, E; Grogan, J A; Niebur, G L; McNamara, L M; McHugh, P E

2013-04-01

Bone marrow found within the porous structure of trabecular bone provides a specialized environment for numerous cell types, including mesenchymal stem cells (MSCs). Studies have sought to characterize the mechanical environment imposed on MSCs, however, a particular challenge is that marrow displays the characteristics of a fluid, while surrounded by bone that is subject to deformation, and previous experimental and computational studies have been unable to fully capture the resulting complex mechanical environment. The objective of this study was to develop a fluid structure interaction (FSI) model of trabecular bone and marrow to predict the mechanical environment of MSCs in vivo and to examine how this environment changes during osteoporosis. An idealized repeating unit was used to compare FSI techniques to a computational fluid dynamics only approach. These techniques were used to determine the effect of lower bone mass and different marrow viscosities, representative of osteoporosis, on the shear stress generated within bone marrow. Results report that shear stresses generated within bone marrow under physiological loading conditions are within the range known to stimulate a mechanobiological response in MSCs in vitro. Additionally, lower bone mass leads to an increase in the shear stress generated within the marrow, while a decrease in bone marrow viscosity reduces this generated shear stress.

In vitro deposition of hydroxyapatite on cortical bone collagen stimulated by deformation-induced piezoelectricity.

PubMed

Noris-Suárez, Karem; Lira-Olivares, Joaquin; Ferreira, Ana Marina; Feijoo, José Luis; Suárez, Nery; Hernández, Maria C; Barrios, Esteban

2007-03-01

In the present work, we have studied the effect of the piezoelectricity of elastically deformed cortical bone collagen on surface using a biomimetic approach. The mineralization process induced as a consequence of the piezoelectricity effect was evaluated using scanning electron microscopy (SEM), thermally stimulated depolarization current (TSDC), and differential scanning calorimetry (DSC). SEM micrographs showed that mineralization occurred predominantly over the compressed side of bone collagen, due to the effect of piezoelectricity, when the sample was immersed in the simulated body fluid (SBF) in a cell-free system. The TSDC method was used to examine the complex collagen dielectric response. The dielectric spectra of deformed and undeformed collagen samples with different hydration levels were compared and correlated with the mineralization process followed by SEM. The dielectric measurements showed that the mineralization induced significant changes in the dielectric spectra of the deformed sample. DSC and TSDC results demonstrated a reduction of the collagen glass transition as the mineralization process advanced. The combined use of SEM, TSDC, and DSC showed that, even without osteoblasts present, the piezoelectric dipoles produced by deformed collagen can produce the precipitation of hydroxyapatite by electrochemical means, without a catalytic converter as occurs in classical biomimetic deposition.

Measurement of Strain Distributions in Mouse Femora with 3D-Digital Speckle Pattern Interferometry

PubMed Central

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

Decreased nitric oxide levels stimulate osteoclastogenesis and bone resorption both in vitro and in vivo on the chick chorioallantoic membrane in association with neoangiogenesis.

PubMed

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.

STC1 interference on calcitonin family of receptors signaling during osteoblastogenesis via adenylate cyclase inhibition.

PubMed

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.

Bone Augmentation in Rabbit Tibia Using Microfixed Cobalt-Chromium Membranes with Whole Blood and Platelet-Rich Plasma

PubMed Central

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

Genetic confirmation for a central role for TNFα in the direct action of thyroid stimulating hormone on the skeleton

PubMed Central

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

Leukemia inhibitory factor: a novel bone-active cytokine.

PubMed

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.

Different Movement of Hyolaryngeal Structures by Various Application of Electrical Stimulation in Normal Individuals

PubMed Central

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

Economic evaluation of bone stimulation modalities: A systematic review of the literature.

PubMed

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.

Electrical stimulation at the dorsal root ganglion preserves trabecular bone mass and microarchitecture of the tibia in hindlimb-unloaded rats.

PubMed

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.

A New Piezoelectric Actuator Induces Bone Formation In Vivo: A Preliminary Study

PubMed Central

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

Binaural Hearing Ability With Bilateral Bone Conduction Stimulation in Subjects With Normal Hearing: Implications for Bone Conduction Hearing Aids.

PubMed

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.

Antithetical effects of hemicellulase-treated Agaricus blazei on the maturation of murine bone-marrow-derived dendritic cells

PubMed Central

Kawamura, Masaki; Kasai, Hirotake; He, Limin; Deng, Xuewen; Yamashita, Atsuya; Terunuma, Hiroshi; Horiuchi, Isao; Tanabe, Fuminori; Ito, Masahiko

2005-01-01

We report the effects of hemicellulase-treated Agaricus blazei (ABH) on the maturation of bone-marrow-derived dendritic cells (BMDCs). ABH activated immature BMDCs, inducing up-regulation of surface molecules, such as CD40, CD80 and major histocompatibility complex class I antigens, as well as inducing allogeneic T-cell proliferation and T helper type 1 cell development. However, unlike lipopolysaccharide (LPS), ABH did not stimulate the BMDCs to produce proinflammatory cytokines, such as interleukin-12 (IL-12) p40, tumour necrosis factor-α, or IL-1β. In addition, ABH suppressed LPS-induced DC responses. Pretreatment of DCs with ABH markedly reduced the levels of LPS-induced cytokine secretion, while only slightly decreasing up-regulation of the surface molecules involved in maturation. ABH also had a significant impact on peptidoglycan-induced or CpG oligodeoxynucleotide-induced IL-12p40 production in DCs. The inhibition of LPS-induced responses was not associated with a cytotoxic effect of ABH nor with an anti-inflammatory effect of IL-10. However, ABH decreased NF-κB-induced reporter gene expression in LPS-stimulated J774.1 cells. Interestingly, DCs preincubated with ABH and then stimulated with LPS augmented T helper type 1 responses in culture with allogeneic T cells as compared to LPS-stimulated but non-ABH-pretreated DCs. These observations suggest that ABH regulates DC-mediated responses. PMID:15720441

[Usage of Cerasorbe in complex treatment of chronic generalized periodontitis (clinical-experimental study)].

PubMed

Motsonelidze, N R; Okropiridze, T V; Kapanadze, R V

2005-01-01

The effectiveness of the bioactive osteoplastic composition--Cerasorbe--at a surgical stage of combined treatment of chronic generalized periodontitis was examined. The results obtained in the study and the control groups prove, that Cerasorbe allows reduction of the treatment duration and achieves remission of the disease. From 127 patients with chronic generalized periodontitis 65 were operated by microplasmatic scalpel-irradiator as a part of a complex treatment. The treatment course comprised of 3-5 procedures. The quantity of manipulations was determined by the severity of the pathological process. Before and after the treatment the radiographical investigation was carried out in both groups. At the 18th month after the surgical intervention bone regeneration, confirmed by radiography, was shown in 87,8% cases in the study group and in 60,1% in the control group. The work presents experimental and morphological studies of regeneration of damaged areas of maxillo-facial bones. Time course of healing of defects in the lower jaw bone filled with Cerasorb was studied in experiment on rabbits. On days 7, 14, 21 and 28 four rabbits from each group were killed and the defects were investigation by X-ray and histological methods. We have stained the micropreparations by hematoxilin-eosine. In experiments with Cerasorb, bone regenerations replaced up to one half of the defect area by the day 28. We have shown high efficiency of Cerasorb in experiment and during complex treatment. Cerasorb stimulated reparative osteogenesis and can be recommended for using in the clinical practice.

Rapamycin inhibits BMP-7-induced osteogenic and lipogenic marker expressions in fetal rat calvarial cells.

PubMed

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.

Osteopenia and osteoporosis in people living with HIV: multiprofessional approach

PubMed Central

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

Osteopenia and osteoporosis in people living with HIV: multiprofessional approach.

PubMed

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.

Association of Stimulant Medication Use With Bone Mass in Children and Adolescents With Attention-Deficit/Hyperactivity Disorder.

PubMed

Feuer, Alexis J; Thai, Ashley; Demmer, Ryan T; Vogiatzi, Maria

2016-12-05

Murine studies reveal that sympathetic nervous system activation leads to decreased bone mass. Stimulant medications used to treat attention-deficit/hyperactivity disorder (ADHD) increase sympathetic tone and may affect bone remodeling. Because bone mass accrual is completed by young adulthood, assessing stimulant effects on bone density in growing children is of critical importance. To investigate associations between stimulant use and bone mass in children and adolescents. This cross-sectional analysis used data collected from January 1, 2005, to December 31, 2010, from the National Health and Nutrition Examination Survey (NHANES) database. NHANES is a series of cross-sectional, nationally representative health and nutrition surveys of the US population. All children, adolescents, and young adults aged 8 to 20 years with dual-energy x-ray absorptiometry (DXA), anthropometric, demographic, and prescription medication use data were eligible for participation. Of the 6489 respondents included in the multivariable linear regression analysis, 159 were stimulant users and 6330 were nonusers. Data were analyzed from October 8, 2015, to December 31, 2016. Stimulant use, determined by questionnaires administered via interview. The association between stimulant use and total femur, femoral neck, and lumbar spine bone mineral content (BMC) and bone mineral density (BMD) was assessed using DXA. Study participants included 6489 NHANES participants with a mean (SD) age of 13.6 (3.6) years. Stimulant use was associated with lower bone mass after adjustment for covariates. Mean lumbar spine BMC was significantly lower in stimulant users vs nonusers (12.76 g; 95% CI, 12.28-13.27 g vs 13.38 g; 95% CI, 13.26-13.51 g; P = .02), as was mean lumbar spine BMD (0.90 g/cm2; 95% CI, 0.87-0.94 g/cm2 vs 0.94 g/cm2; 95% CI, 0.94-0.94 g/cm2; P = .03) and mean femoral neck BMC (4.34 g; 95% CI, 4.13-4.57 g vs 4.59 g; 95% CI, 4.56-4.62 g; P = .03). Mean BMD of the femoral neck (0.88 g/cm2; 95% CI, 0.84-0.91 g/cm2 vs 0.91 g/cm2; 95% CI, 0.90-0.91 g/cm2; P = .08) and total femur (0.94 g/cm2; 95% CI, 0.90-0.99 g/cm2 vs 0.99 g/cm2; 95% CI, 0.98-0.99 g/cm2; P = .05) were also lower in stimulant users vs nonusers. Participants treated with stimulants for 3 months or longer had significantly lower lumbar spine BMD (0.89 g/cm2; 95% CI, 0.85-0.93 g/cm2 vs 0.94 g/cm2; 95% CI, 0.94-0.94 g/cm2; P = .02) and BMC (12.71 g; 95% CI, 12.14-13.32 g vs 13.38 g; 95% CI, 13.25-13.51 g; P = .03) and femoral neck BMD (0.87 g/cm2; 95% CI, 0.74-0.83 g/cm2 vs 0.91 g/cm2; 95% CI, 0.83-0.84 g/cm2; P = .048) than nonusers. Children and adolescents reporting stimulant use had lower DXA measurements of the lumbar spine and femur compared with nonusers. These findings support the need for future prospective studies to examine the effects of stimulant use on bone mass in children.

Spinal Cord Injury-Induced Osteoporosis: Pathogenesis and Emerging Therapies

PubMed Central

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

Use of G-CSF-stimulated marrow in allogeneic hematopoietic stem cell transplantation settings: a comprehensive review.

PubMed

Chang, Ying-Jun; Huang, Xiao-Jun

2011-01-01

In recent years, several researchers have unraveled the previously unrecognized effects of granulocyte colony-stimulating factor (G-CSF) on hematopoiesis and the immune cell functions of bone marrow in healthy donors. In human leukocyte antigen-matched or haploidentical transplant settings, available data have established the safety of using G-CSF-stimulated bone marrow grafts, as well as the ability of this source to produce rapid and sustained engraftment. Interestingly, G-CSF-primed bone marrow transplants could capture the advantages of blood stem cell transplants, without the increased risk of chronic graft-versus-host disease that is associated with blood stem cell transplants. This review summarizes the growing body of evidence that supports the use of G-CSF-stimulated bone marrow grafts as an alternative stem cell source in allogeneic hematopoietic stem cell transplantation. © 2010 John Wiley & Sons A/S.

Macrophages – Key Cells in the Response to Wear Debris from Joint Replacements

PubMed Central

Nich, Christophe; Takakubo, Yuya; Pajarinen, Jukka; Ainola, Mari; Salem, Abdelhakim; Sillat, Tarvo; Rao, Allison J.; Raska, Milan; Tamaki, Yasunobu; Takagi, Michiaki; Konttinen, Yrjö T.; Goodman, Stuart B.; Gallo, Jiri

2013-01-01

The generation of wear debris is an inevitable result of normal usage of joint replacements. Wear debris particles stimulate local and systemic biological reactions resulting in chronic inflammation, periprosthetic bone destruction, and eventually, implant loosening and revision surgery. The latter may be indicated in up to 15% patients in the decade following the arthroplasty using conventional polyethylene. Macrophages play multiple roles in both inflammation and in maintaining tissue homeostasis. As sentinels of the innate immune system, they are central to the initiation of this inflammatory cascade, characterized by the release of pro-inflammatory and pro-osteoclastic factors. Similar to the response to pathogens, wear particles elicit a macrophage response, based on the unique properties of the cells belonging to this lineage, including sensing, chemotaxis, phagocytosis, and adaptive stimulation. The biological processes involved are complex, redundant, both local and systemic, and highly adaptive. Cells of the monocyte/macrophage lineage are implicated in this phenomenon, ultimately resulting in differentiation and activation of bone resorbing osteoclasts. Simultaneously, other distinct macrophage populations inhibit inflammation and protect the bone-implant interface from osteolysis. Here, the current knowledge about the physiology of monocyte/macrophage lineage cells is reviewed. In addition, the pattern and consequences of their interaction with wear debris and the recent developments in this field are presented. PMID:23568608

[Significance of Matrix-augmented Bone Marrow Stimulation for Treatment of Cartilage Defects of the Knee: A Consensus Statement of the DGOU Working Group on Tissue Regeneration].

PubMed

Niemeyer, Philipp; Becher, Christoph; Buhs, Matthias; Fickert, Stefan; Gelse, Kolja; Günther, Daniel; Kaelin, Raphael; Kreuz, Peter; Lützner, Jörg; Nehrer, Stefan; Madry, Henning; Marlovits, Stefan; Mehl, Julian; Ott, Henning; Pietschmann, Matthias; Spahn, Gunther; Tischer, Thomas; Volz, Martin; Walther, Markus; Welsch, Götz; Zellner, Johannes; Zinser, Wolfgang; Angele, Peter

2018-06-18

Surgical principles for treatment of full-thickness cartilage defects of the knee include bone marrow stimulation techniques (i.e. arthroscopic microfracturing) and transplantation techniques (i.e. autologous chondrocyte implantation and osteochondral transplantation). On the basis of increasing scientific evidence, indications for these established therapeutical concepts have been specified and clear recommendations for practical use have been given. Within recent years, matrix-augmented bone marrow stimulation has been established as a new treatment concept for chondral lesions. To date, scientific evidence is limited and specific indications are still unclear. The present paper gives an overview of available products as well as preclinical and clinical scientific evidence. On the basis of the present evidence and an expert consensus from the "Working Group on Tissue Regeneration" of the German Orthopaedic and Trauma Society (DGOU), indications are specified and recommendations for the use of matrix-augmented bone marrow stimulation are given. In principle, it can be stated that the various products offered in this field differ considerably in terms of the number and quality of related studies (evidence level). Against the background of the current data situation, their application is currently seen in the border area between cell transplantation and bone marrow stimulation techniques, but also as an improvement on traditional bone marrow stimulation within the indication range of microfracturing. The recommendations of the Working Group have preliminary character and require re-evaluation after improvement of the study situation. Georg Thieme Verlag KG Stuttgart · New York.

Effects of a buried magnetic field on cranial bone reconstruction in rats

PubMed Central

de ABREU, Maíra Cavallet; PONZONI, Deise; LANGIE, Renan; ARTUZI, Felipe Ernesto; PURICELLI, Edela

2016-01-01

ABSTRACT The understanding of bone repair phenomena is a fundamental part of dentistry and maxillofacial surgery. Objective The present study aimed to evaluate the influence of buried magnetic field stimulation on bone repair in rat calvaria after reconstruction with autogenous bone grafts, synthetic powdered hydroxyapatite, or allogeneic cartilage grafts, with or without exposure to magnetic stimulation. Material and Methods Ninety male Wistar rats were divided into 18 groups of five animals each. Critical bone defects were created in the rats’ calvaria and immediately reconstructed with autogenous bone, powdered synthetic hydroxyapatite or allogeneic cartilage. Magnetic implants were also placed in half the animals. Rats were euthanized for analysis at 15, 30, and 60 postoperative days. Histomorphometric analyses of the quantity of bone repair were performed at all times. Results These analyses showed significant group by postoperative time interactions (p=0.008). Among the rats subjected to autogenous bone reconstruction, those exposed to magnetic stimulation had higher bone fill percentages than those without magnetic implants. Results also showed that the quality of bone repair remained higher in the former group as compared to the latter at 60 postoperative days. Conclusions After 60 postoperative days, bone repair was greater in the group treated with autogenous bone grafts and exposed to a magnetic field, and bone repair was most pronounced in animals treated with autogenous bone grafts, followed by those treated with powdered synthetic hydroxyapatite and allogeneic cartilage grafts. PMID:27119765

Low-Intensity Vibration as a Treatment for Traumatic Muscle Injury

DTIC Science & Technology

2017-08-01

stimulation has an anabolic effect on musculoskeletal tissues, and mechanical stimulation via LIV has been shown to accelerate bone regeneration. Our... bone marrow-derived cells (BMDC) in LIV-induced improvements in muscle healing. Third, we will identify specific cells that detect and transduce...muscle regeneration following traumatic injury. 2. Determine the role of bone marrow-derived cells (BMDC) in LIV-induced improvements in muscle

Regulation of human bone sialoprotein gene transcription by platelet-derived growth factor-BB.

PubMed

Mezawa, Masaru; Araki, Shouta; Takai, Hideki; Sasaki, Yoko; Wang, Shuang; Li, Xinyue; Kim, Dong-Soon; Nakayama, Youhei; Ogata, Yorimasa

2009-04-15

Platelet-derived growth factor (PDGF) is produced by mesenchymal cells and released by platelets following aggregation and is synthesized by osteoblasts. In bone, PDGF stimulates proliferation and differentiation of osteoblasts. PDGF also increases bone resorption, most likely by increasing the number of osteoclasts. Bone sialoprotein (BSP) is thought to function in the initial mineralization of bone, selectively expressed by differentiated osteoblast. To determine the molecular mechanisms PDGF regulation of human BSP gene transcription, we have analyzed the effects of PDGF-BB on osteoblast-like Saos2 and ROS17/2.8 cells. PDGF-BB (5 ng/ml) increased BSP mRNA and protein levels at 12 h in Saos2 cells, and induced BSP mRNA expression at 3 h, reached maximal at 12 h in ROS17/2.8 cells. Transient transfection analyses were performed using chimeric constructs of the human BSP gene promoter linked to a luciferase reporter gene. Treatment of Saos2 cells with PDGF-BB (5 ng/ml, 12 h) increased luciferase activities of all constructs between -184LUC to -2672LUC including the human BSP gene promoter. Effects of PDGF-BB abrogated in constructs included 2 bp mutations in the two cAMP response elements (CRE1 and CRE2), activator protein 1(3) (AP1(3)) and shear stress response element 1 (SSRE1). Luciferase activities induced by PDGF-BB were blocked by protein kinase A inhibitor H89 and tyrosine kinase inhibitor herbimycin A. Gel mobility shift analyses showed that PDGF-BB increased binding of CRE1, CRE2, AP1(3) and SSRE1 elements. CRE1- and CRE2-protein complexes were supershifted by CREB1 and phospho-CREB1 antibodies. Notably, AP1(3)-protein complexes were supershifted by c-Fos and JunD, and disrupted by CREB1, phospho-CREB1, c-Jun and Fra2 antibodies. These studies, therefore, demonstrate that PDGF-BB stimulates human BSP transcription by targeting the CRE1, CRE2, AP1(3) and SSRE1 elements in the human BSP gene promoter.

Osthole Stimulates Osteoblast Differentiation and Bone Formation by Activation of β-Catenin–BMP Signaling

PubMed Central

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

Selective inhibitors of the osteoblast proteasome stimulate bone formation in vivo and in vitro

PubMed Central

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

Stimulation of fibroblast growth factor 23 by metabolic acidosis requires osteoblastic intracellular calcium signaling and prostaglandin synthesis.

PubMed

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.

Prostaglandin E2 acts via bone marrow macrophages to block PTH-stimulated osteoblast differentiation in vitro

PubMed Central

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

BMP delivery complements the guiding effect of scaffold architecture without altering bone microstructure in critical-sized long bone defects: A multiscale analysis.

PubMed

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.

The anabolic activity of bone tissue, suppressed by disuse, is normalized by brief exposure to extremely low-magnitude mechanical stimuli

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.

Characterization of an Ex vivo Femoral Head Model Assessed by Markers of Bone and Cartilage Turnover

PubMed Central

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

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

Neonatal High Bone Mass With First Mutation of the NF-κB Complex: Heterozygous De Novo Missense (p.Asp512Ser) RELA (Rela/p65).

PubMed

Frederiksen, Anja L; Larsen, Martin J; Brusgaard, Klaus; Novack, Deborah V; Knudsen, Peter Juel Thiis; Schrøder, Henrik Daa; Qiu, Weimin; Eckhardt, Christina; McAlister, William H; Kassem, Moustapha; Mumm, Steven; Frost, Morten; Whyte, Michael P

2016-01-01

Heritable disorders that feature high bone mass (HBM) are rare. The etiology is typically a mutation(s) within a gene that regulates the differentiation and function of osteoblasts (OBs) or osteoclasts (OCs). Nevertheless, the molecular basis is unknown for approximately one-fifth of such entities. NF-κB signaling is a key regulator of bone remodeling and acts by enhancing OC survival while impairing OB maturation and function. The NF-κB transcription complex comprises five subunits. In mice, deletion of the p50 and p52 subunits together causes osteopetrosis (OPT). In humans, however, mutations within the genes that encode the NF-κB complex, including the Rela/p65 subunit, have not been reported. We describe a neonate who died suddenly and unexpectedly and was found at postmortem to have HBM documented radiographically and by skeletal histopathology. Serum was not available for study. Radiographic changes resembled malignant OPT, but histopathological investigation showed morphologically normal OCs and evidence of intact bone resorption excluding OPT. Furthermore, mutation analysis was negative for eight genes associated with OPT or HBM. Instead, accelerated bone formation appeared to account for the HBM. Subsequently, trio-based whole exome sequencing revealed a heterozygous de novo missense mutation (c.1534_1535delinsAG, p.Asp512Ser) in exon 11 of RELA encoding Rela/p65. The mutation was then verified using bidirectional Sanger sequencing. Lipopolysaccharide stimulation of patient fibroblasts elicited impaired NF-κB responses compared with healthy control fibroblasts. Five unrelated patients with unexplained HBM did not show a RELA defect. Ours is apparently the first report of a mutation within the NF-κB complex in humans. The missense change is associated with neonatal osteosclerosis from in utero increased OB function rather than failed OC action. These findings demonstrate the importance of the Rela/p65 subunit within the NF-κB pathway for human skeletal homeostasis and represent a new genetic cause of HBM. © 2015 American Society for Bone and Mineral Research.

Genetic Regulation of Bone and Cells by Electromagnetic Stimulation Fields and Uses Thereof

NASA Technical Reports Server (NTRS)

Shackelford, Linda C. (Inventor); Goodwin, Thomas J. (Inventor)

2018-01-01

The present invention provides methods to modify the genetic regulation of mammalian tissue, bone, cells or any combination thereof by preferential activation, up-regulation and/or down-regulation. The method comprises steps of tuning the predetermined profiles of one or more time-varying stimulation fields by manipulating the B-Field magnitude, rising slew rate, rise time, falling slew rate, fall time, frequency, wavelength, and duty cycle, and exposing mammalian cells or tissues to one or more tuned time-varying stimulation fields with predetermined profiles. Examples of mammalian cells or tissues are chondrocytes, osteoblasts, osteocytes, osteoclasts, nucleus pulposus, associated tissue, or any combination. The resulted modification on gene regulation of these cells, tissues or bones may promote the retention, repair of and reduction of compromised mammalian cartilage, bone, and associated tissue.

Bone modeling and remodeling: potential as therapeutic targets for the treatment of osteoporosis.

PubMed

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.

Role of Adrenomedullin in Breast Cancer Bone Metastasis and Chemoresistance

DTIC Science & Technology

2008-05-01

osteoblast proliferation but does not induce bone matrix protein (bone sialoprotein , type I collagen, osteocalcin, and osteopontin) mRNA expression...are incompletely understood. AM treatment stimulates osteoblast proliferation but does not induce bone matrix protein (bone sialoprotein , type I

Cochlear excitation by the near-field component during stimulation through the partially occluded round window

NASA Astrophysics Data System (ADS)

Weddell, Thomas D.; Yarin, Yury M.; Drexl, Markus; Russell, Ian J.; Elliott, Stephen J.; Lukashkin, Andrei N.

2015-12-01

The round window membrane (RW) provides pressure relief when the cochlea is excited by sound. While normal function of the RW is important for effective stimulation of the cochlea through the conventional oval window route, the cochlea can be stimulated successfully in non-conventional ways (e.g. through bone conduction, through the RW, and through perforations in the cochlea's apical turn). We report measurements of cochlear function from guinea pigs when the cochlea was stimulated at acoustic frequencies by movements of a miniature magnet which partially occluded the RW. Neural response latencies to acoustic and RW stimulation were similar and taken to indicate that both means of stimulation resulted in the generation of conventional travelling waves along the cochlear partition. It was concluded that the relatively high impedance of the ossicles, as seen from the cochlea, enabled the region of the RW not occluded by the magnet, to act as a pressure shunt during RW stimulation. We propose that travelling waves, similar to those due to acoustic far-field pressure changes, are driven by a jet-like, near-field component of a complex fluid-pressure field, which is generated by the magnetically vibrated RW.

Effect of daily short-duration weight-bearing on disuse-induced deterioration of musculoskeletal system

PubMed Central

Leung, K-S.; Li, Y-H.; Liu, Y.; Wang, H.; Tam, K-F.; Chow, D.H.K.; Wan, Y.; Ling, S.; Dai, Z.; Qin, L.; Cheung, W-H.

2015-01-01

Objectives: To investigate deterioration of musculoskeletal system due to prolonged disuse and the potential of daily short-duration weight-bearing as countermeasures. Methods: Twenty-four adult male Sprague-Dawley rats were divided into Control Group (CG, no intervention), Tail-suspension Group (TG, tail-suspension without treatment), and Weight-Bearing Group (WBG, tail-suspension with 20 min/day, 5 days/week body weight loading). After four weeks of treatment, femur and tibia, soleus and extensor digitorum longus were evaluated for bone and muscle quality respectively. Tensile properties of bone-tendon insertion (BTI) were evaluated using patella-patellar tendon complex. Results: Disuse induced deterioration on bone, muscle, and BTI after four weeks. Compared with CG, TG and WBG showed significant decrease in bone mineral density (BMD) of trabecular bone in distal femur (4.3-15.2%), muscle mass (31.3-52.3%), muscle cross-sectional area (29.1-35%), and failure strength of BTI (23.9-29.4%). Tensile test showed that the failure mode was avulsion of bone at the BTI. No significant difference was detected between TG and WBG for all assessments on bone, muscle, and BTI. Conclusions: Disuse caused deterioration of bone, muscle, and BTI while daily short-duration of weight-bearing did not prevent this deterioration. Mechanical stimulation with higher intensity and longer duration may be necessary to prevent musculoskeletal deterioration resulted from prolonged disuse. PMID:26032214

Skeletal unloading causes resistance of osteoprogenitor cells to parathyroid hormone and to insulin-like growth factor-I

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.

Pharmacological inhibition of lysosomes activates the MTORC1 signaling pathway in chondrocytes in an autophagy-independent manner.

PubMed

Newton, Phillip T; Vuppalapati, Karuna K; Bouderlique, Thibault; Chagin, Andrei S

2015-01-01

Mechanistic target of rapamycin (serine/threonine kinase) complex 1 (MTORC1) is a protein-signaling complex at the fulcrum of anabolic and catabolic processes, which acts depending on wide-ranging environmental cues. It is generally accepted that lysosomes facilitate MTORC1 activation by generating an internal pool of amino acids. Amino acids activate MTORC1 by stimulating its translocation to the lysosomal membrane where it forms a super-complex involving the lysosomal-membrane-bound vacuolar-type H(+)-ATPase (v-ATPase) proton pump. This translocation and MTORC1 activation require functional lysosomes. Here we found that, in contrast to this well-accepted concept, in epiphyseal chondrocytes inhibition of lysosomal activity by v-ATPase inhibitors bafilomycin A1 or concanamycin A potently activated MTORC1 signaling. The activity of MTORC1 was visualized by phosphorylated forms of RPS6 (ribosomal protein S6) and EIF4EBP1, 2 well-known downstream targets of MTORC1. Maximal RPS6 phosphorylation was observed at 48-h treatment and reached as high as a 12-fold increase (p < 0.018). This activation of MTORC1 was further confirmed in bone organ culture and promoted potent stimulation of longitudinal growth (p < 0.001). Importantly, the same effect was observed in ATG5 (autophagy-related 5)-deficient bones suggesting a macroautophagy-independent mechanism of MTORC1 inhibition by lysosomes. Thus, our data show that in epiphyseal chondrocytes lysosomes inhibit MTORC1 in a macroautophagy-independent manner and this inhibition likely depends on v-ATPase activity.

Osteoimmunology: Influence of the Immune System on Bone Regeneration and Consumption.

PubMed

Limmer, Andreas; Wirtz, Dieter C

2017-06-01

Background Stimulating bone regeneration is a central aim in orthopaedic and trauma surgery. Although the replacement of bone with artificial materials like cement or apatite helps to keep up bone stability, new bone often cannot be regenerated. Increasing research efforts have led to the clinical application of growth factors stimulating bone growth (e.g. bone morphogenic protein, BMP) and inhibitors preventing bone consumption (e.g. RANKL blocking antibodies). These factors mostly concentrate on stimulating osteoblast or preventing osteoclast activity. Current Situation It is widely accepted that osteoblasts and osteoclasts are central players in bone regeneration. This concept assumes that osteoblasts are responsible for bone growth while osteoclasts cause bone consumption by secreting matrix-degrading enzymes such as cathepsin K and matrix metalloproteinases (MMP). However, according to new research results, bone growth or consumption are not regulated by single cell types. It is rather the interaction of various cell types that regulates bone metabolism. While factors secreted by osteoblasts are essential for osteoclast differentiation and activation, factors secreted by activated osteoclasts are essential for osteoblast activity. In addition, recent research results imply that the influence of the immune system on bone metabolism has long been neglected. Factors secreted by macrophages or T cells strongly influence bone growth or degradation, depending on the bone microenvironment. Infections, sterile inflammation or tumour metastases not only affect bone cells directly, but also influence immune cells such as T cells indirectly. Furthermore, immune cells and bone are mechanistically regulated by similar factors such as cytokines, chemokines and transcription factors, suggesting that the definition of bone and immune cells has to be thought over. Outlook Bone and the immune system are regulated by similar mechanisms. These newly identified similarities between bone and the immune system imply that medication developed for tumour and autoimmune patients could also be applied in bone diseases. Georg Thieme Verlag KG Stuttgart · New York.

Fluid volume displacement at the oval and round windows with air and bone conduction stimulation.

PubMed

Stenfelt, Stefan; Hato, Naohito; Goode, Richard L

2004-02-01

The fluids in the cochlea are normally considered incompressible, and the fluid volume displacement of the oval window (OW) and the round window (RW) should be equal and of opposite phase. However, other channels, such as the cochlear and vestibular aqueducts, may affect the fluid flow. To test if the OW and RW fluid flows are equal and of opposite phase, the volume displacement was assessed by multiple point measurement at the windows with a laser Doppler vibrometer. This was done during air conduction (AC) stimulation in seven fresh human temporal bones, and with bone conduction (BC) stimulation in eight temporal bones and one human cadaver head. With AC stimulation, the average volume displacement of the two windows is within 3 dB, and the phase difference is close to 180 degrees for the frequency range 0.1 to 10 kHz. With BC stimulation, the average volume displacement difference between the two windows is greater: below 2 kHz, the volume displacement at the RW is 5 to 15 dB greater than at the OW and above 2 kHz more fluid is displaced at the OW. With BC stimulation, lesions at the OW caused only minor changes of the fluid flow at the RW.

Fluid volume displacement at the oval and round windows with air and bone conduction stimulation

NASA Astrophysics Data System (ADS)

Stenfelt, Stefan; Hato, Naohito; Goode, Richard L.

2004-02-01

The fluids in the cochlea are normally considered incompressible, and the fluid volume displacement of the oval window (OW) and the round window (RW) should be equal and of opposite phase. However, other channels, such as the cochlear and vestibular aqueducts, may affect the fluid flow. To test if the OW and RW fluid flows are equal and of opposite phase, the volume displacement was assessed by multiple point measurement at the windows with a laser Doppler vibrometer. This was done during air conduction (AC) stimulation in seven fresh human temporal bones, and with bone conduction (BC) stimulation in eight temporal bones and one human cadaver head. With AC stimulation, the average volume displacement of the two windows is within 3 dB, and the phase difference is close to 180° for the frequency range 0.1 to 10 kHz. With BC stimulation, the average volume displacement difference between the two windows is greater: below 2 kHz, the volume displacement at the RW is 5 to 15 dB greater than at the OW and above 2 kHz more fluid is displaced at the OW. With BC stimulation, lesions at the OW caused only minor changes of the fluid flow at the RW.

Direct current stimulation of bone production in the horse: preliminary study with a "gap healing" model.

PubMed

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.

Maximizing PTH Anabolic Osteoporosis Therapy

DTIC Science & Technology

2014-09-01

PTH- stimulated addition of trabecular bone at 3 weeks of hor- mone treatment, and that Nmp4 has a profound regulatory role in BM population dynamics...Qin L, LJ Raggatt, and Partridge. (2004). Parathyroid hor- mone : a double-edged sword for bone metabolism. Trends Endocrinol Metab 15:60–65. 14. Kular...parathyroid hor- mone administration is due to the stimulation of prolifera- tion and differentiation of osteoprogenitor cells in BM. Bone 15:717–723. 16

MMP-8, A Breast Cancer Bone Metastasis Suppressor Gene

DTIC Science & Technology

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

Dietary isoflavones act on bone marrow osteoprogenitor cells and stimulate ovary development before influencing bone mass in pre-pubertal piglets.

PubMed

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.

Cell-specific paracrine actions of IL-6 family cytokines from bone, marrow and muscle that control bone formation and resorption.

PubMed

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.

Bone loss during long term space flight is prevented by the application of a short term impulsive mechanical stimulus

NASA Astrophysics Data System (ADS)

Goodship, A. E.; Cunningham, J. L.; Oganov, V.; Darling, J.; Miles, A. W.; Owen, G. W.

In long term space flight, the mechanical forces applied to the skeleton are substantially reduced and are altered in character. This reduced skeletal loading results in a reduction in bone mass. Exercise techmques currently used in space can maintain muscle mass but the mechanical stimulus provided by this exercise does not prevent bone loss. By applying an external impulsive load for a short period each day, which is intended to mimic the heel strike transient, to the lower limb of an astronaut during a long term space flight (5 months), this study tests the hypothesis that the bone cells can be activated by an appropriate external mechanical stimulus to maintain bone mass throughout prolonged periods of weightlessness. A mechanical loading device was developed to produce a loading of the os-calcis similar to that observed during the heel strike transient. The device is activated by the astronaut to provide a transient load to the heel of one leg whilst providing an equivalent exercising load to the other leg. During the EUROMIR95 mission on the MIR space station, an astronaut used this device for a short period daily throughout the duration of the mission. Pre- and post-flight measurements of bone mineral density (BMD) of the os-calcis and femoral neck of the astronaut were made to determine the efficacy of the device in preventing loss of bone mineral during the mission. On the os-calcis which received the mechanical stimulus, BMD was maintained throughout the period of the flight, while it was reduced by up to 7% on the os-calcis which received no stimulus. Post-flight, BMD in both the stimulated and non-stimulated os-calcis reduces, the extent of this reduction however is less in the stimulated os-calcis. For the femoral neck, the mechanical Stimulation does not produce a positive effect. On the os-calcis which received the mechanical stimulus, BMD was maintained throughout the period of the flight, while it was reduced by up to 7% on the os-calcis which received no stimulus. Post-flight, BMD in both the stimulated and non-stimulated os-calcis reduces, the extent of this reduction however is less in the stimulated os-calcis. For the femoral neck, the mechanical stimulation does not produce a positive effect.

Low-level laser therapy stimulates bone metabolism and inhibits root resorption during tooth movement in a rodent model.

PubMed

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.

Gonadal steroids and bone metabolism in men.

PubMed

Leder, Benjamin

2007-06-01

Over the past decade, our increasing awareness of the clinical importance of osteoporosis in men has stimulated intense interest in trying to better understand male skeletal physiology and pathophysiology. The present review focuses on a major focus of research in this area, namely the attempt to define the influence and therapeutic potential of gonadal steroids in male bone metabolism. Building on previous work defining the relative roles of androgens and estrogens in the developing male skeleton and in maintaining normal bone turnover, recent studies have begun to define these issues from epidemiologic, physiologic and therapeutic perspectives. With access to data from large prospectively defined populations of men, investigators are confirming and challenging existing hypotheses and forwarding new concepts. Clinical trials have expanded beyond standard androgen replacement studies to explore more complex hormonal interventions. Physiologic investigation has continued to probe the mechanisms underlying the differential and independent roles of androgens and estrogens in male bone metabolism. Recent work has added significantly to our understanding of the role of gonadal steroids in male skeletal physiology. Nonetheless, further research is necessary to build on these initial human studies and to capitalize on rapidly emerging advances in our understanding of the basic biology of bone metabolism.

Gastrodin inhibits osteoclastogenesis via down-regulating the NFATc1 signaling pathway and stimulates osseointegration in vitro

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

3D printed scaffolds of calcium silicate-doped β-TCP synergize with co-cultured endothelial and stromal cells to promote vascularization and bone formation.

PubMed

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.

Leg lengthening - series (image)

MedlinePlus

... as Legg-Perthes disease Previous injuries or bone fractures that may stimulate excessive bone growth Abnormal spinal ... in the bone to be lengthened; usually the lower leg bone (tibia) or upper ... small steps, usually over the course of several months.

Hybrid use of combined and sequential delivery of growth factors and ultrasound stimulation in porous multilayer composite scaffolds to promote both vascularization and bone formation in bone tissue engineering.

PubMed

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.

Endothelial cell stimulating angiogenesis factor.

PubMed

Weiss, J B; McLaughlin, B

1998-04-01

Endothelial cell stimulating angiogenesis factor (ESAF) is a small (> 1000 Da) dialysable non-peptide molecule with potent angiogenic activity. ESAF activates the major pro-matrix metalloproteinases and also uniquely reactivates the complex of these active enzymes with their tissue inhibitors resulting in both active enzyme and inhibitor. These actions may be pivotal in its role as an angiogenic factor. ESAF is primarily involved in angiogenic conditions where inflammatory cells are not evident such as foetal bone growth and electrically stimulated skeletal muscles and proliferative retinopathy. However, high levels also occur in actively growing human intracranial tumours but it is not noticeably elevated in rheumatoid arthritic synovial fluid. Its extreme potency and low molecular mass make its structural determination difficult. Possible therapeutic applications would be in the treatment of ischaemic ulcers, acceleration of fracture repair, infertility and more modestly in the correction of baldness. Analogues of ESAF could be of value in treating angiogenic diseases such as psoriasis and proliferative retinopathy.

Lab-on-a-chip platforms for quantification of multicellular interactions in bone remodeling.

PubMed

George, Estee L; Truesdell, Sharon L; York, Spencer L; Saunders, Marnie M

2018-04-01

Researchers have been using lab-on-a-chip systems to isolate factors for study, simulate laboratory analysis and model cellular, tissue and organ level processes. The technology is increasing rapidly, but the bone field has been slow to keep pace. Novel models are needed that have the power and flexibility to investigate the elegant and synchronous multicellular interactions that occur in normal bone turnover and in disease states in which remodeling is implicated. By removing temporal and spatial limitations and enabling quantification of functional outcomes, the platforms should provide unique environments that are more biomimetic than single cell type systems while minimizing complex systemic effects of in vivo models. This manuscript details the development and characterization of lab-on-a-chip platforms for stimulating osteocytes and quantifying bone remodeling. Our platforms provide the foundation for a model that can be used to investigate remodeling interactions as a whole or as a standard mechanotransduction tool by which isolated activity can be quantified as a function of load. Copyright © 2018 Elsevier Inc. All rights reserved.

Aspects of internal fixation of fractures in porotic bone. Principles, technologies and procedures using locked plate screws.

PubMed

Perren, S M; Linke, B; Schwieger, K; Wahl, D; Schneider, E

2005-01-01

Fractures of the bones of elderly people occur more often and have a more important effect because of a generally diminished ability to coordinate stance and walking. These fractures occur at a lower level of load because of lack of strength of the porotic bone. Prompt recovery of skeletal support function is essential to avoid respiratory and circulatory complications in the elderly. To prevent elderly people from the risks of being bedridden, demanding internal fixation of fractures is required. The weak porotic bone and the high level of uncontrolled loading after internal fixation pose complex problems. A combination of several technical elements of design, application and aftercare in internal fixation are proposed. Internal fixators with locked screws improve the biology and the mechanics of internal fixation. When such fixators are used as elevated splints they may stimulate early callus formation because of their flexibility, the limit of flexibility being set by the demands of resistance and function of the limb. Our own studies of triangulation of locked screws have demonstrated their beneficial effects and unexpected limitations.

Effects of Vitamin K2 on the Development of Osteopenia in Rats as the Models of Osteoporosis

PubMed Central

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

Effect of excitation direction on cochlear macro-mechanics during bone conduction stimulation

NASA Astrophysics Data System (ADS)

Kamieniecki, Konrad; Tudruj, Sylwester; Piechna, Janusz; Borkowski, Paweł

2018-05-01

In many instances of hearing loss, audiological improvement can be made via direct excitation of a temporal bone (i.e., bone conduction). In order to design better and more efficient devices, the macro-mechanics of the bone conduction hearing pathway must be better understood. Based on previous empirical work, numerical models are useful. In this work, we present results of a time-domain Fluid Structure Interaction model that describes stimulation of the bone conduction pathway. The cochlea was modelled as uncoiled and consisted of an oval window, a round window, a basilar membrane and a helicotrema. In order to monitor pressure waves in the perilymph, the fluid was considered compressible. The excitation, in form of sinusoidal velocity, was applied to the cochlea bony walls. The system was excited in three perpendicular directions: along the basilar membrane, perpendicularly to the membrane and transversely to the membrane. The numerical simulation examined which stimulation direction maximally excited the basilar membrane, the pressure distributions for each excitation direction, and the associated mechanics.

Behavioural and cognitive effects of simvastatin dose used in stimulation of bone regeneration in rats.

PubMed

Sousa, Dircilei Nascimento de; Santana, Washington Macedo de; Ferreira, Vania Moraes; Duarte, Wagner Rodrigues

2014-03-01

To analyze the effects of simvastatin (SVT) in the locomotion, anxiety and memory of rats, as a reflection of the administration of a minimum dose capable of stimulating bone regeneration in defects in the calvariae. Surgical procedures were performed in 15 female Wistar rats, 2-month old, to insert the grafting material regenerator (Bone-ceramic®) and/or SVT, followed by behavioural and cognitive assessments in the 7th, 30th and 60th days post surgery. The SVT locally applied with the goal of bone regeneration in defects created in rat calvariae does not interfere with locomotion, anxiety levels and/or memories of rats, except for the first week following surgery, when an anxiolytic effect was observed, as a result of a possible central action. Failure to provoke any response within 30 and 60 days post surgical procedures suggests that SVT may constitute a good choice in stimulating bone regeneration without affecting the long term neural functions.

Low dose PTH improves metaphyseal bone healing more when muscles are paralyzed.

PubMed

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.

Generation of large numbers of dendritic cells from mouse bone marrow cultures supplemented with granulocyte/macrophage colony-stimulating factor

PubMed Central

1992-01-01

Antigen-presenting, major histocompatibility complex (MHC) class II- rich dendritic cells are known to arise from bone marrow. However, marrow lacks mature dendritic cells, and substantial numbers of proliferating less-mature cells have yet to be identified. The methodology for inducing dendritic cell growth that was recently described for mouse blood now has been modified to MHC class II- negative precursors in marrow. A key step is to remove the majority of nonadherent, newly formed granulocytes by gentle washes during the first 2-4 d of culture. This leaves behind proliferating clusters that are loosely attached to a more firmly adherent "stroma." At days 4-6 the clusters can be dislodged, isolated by 1-g sedimentation, and upon reculture, large numbers of dendritic cells are released. The latter are readily identified on the basis of their distinct cell shape, ultrastructure, and repertoire of antigens, as detected with a panel of monoclonal antibodies. The dendritic cells express high levels of MHC class II products and act as powerful accessory cells for initiating the mixed leukocyte reaction. Neither the clusters nor mature dendritic cells are generated if macrophage colony-stimulating factor rather than granulocyte/macrophage colony-stimulating factor (GM-CSF) is applied. Therefore, GM-CSF generates all three lineages of myeloid cells (granulocytes, macrophages, and dendritic cells). Since > 5 x 10(6) dendritic cells develop in 1 wk from precursors within the large hind limb bones of a single animal, marrow progenitors can act as a major source of dendritic cells. This feature should prove useful for future molecular and clinical studies of this otherwise trace cell type. PMID:1460426

Local strategies to prevent and treat osteoporosis.

PubMed

Torstrick, F Brennan; Guldberg, Robert E

2014-03-01

Despite advances in systemic osteoporosis therapeutic outcomes, management of fragility fractures and implant fixation in osteoporotic bone remain difficult clinical challenges. Low initial bone density and a prolonged healing response can lead to fracture nonunion and aseptic implant loosening. Local treatment strategies could be used to prevent fracture, accelerate healing, and increase implant fixation by locally stimulating anabolic pathways or inhibiting catabolic pathways. Local strategies under investigation include direct drug release from injectable materials or implant surface coatings. Common locally delivered drugs include bisphosphonates, parathyroid hormone, and bone morphogenetic proteins, yet additional compounds targeting novel pathways in bone biology are also being actively explored. Mechanical stimulation via low intensity pulsed ultrasound, alone or in combination with drug therapy, may also prove effective to promote local bone healing and implant fixation within osteoporotic bone.

Design and Validation of a Compressive Tissue Stimulator with High-Throughput Capacity and Real-Time Modulus Measurement Capability

PubMed Central

Salvetti, David J.; Pino, Christopher J.; Manuel, Steven G.; Dallmeyer, Ian; Rangarajan, Sanjeet V.; Meyer, Tobias; Kotov, Misha

2012-01-01

Mechanical stimulation has been shown to impact the properties of engineered hyaline cartilage constructs and is relevant for engineering of cartilage and osteochondral tissues. Most mechanical stimulators developed to date emphasize precision over adaptability to standard tissue culture equipment and protocols. The realization of mechanical characteristics in engineered constructs approaching native cartilage requires the optimization of complex variables (type of stimulus, regimen, and bimolecular signals). We have proposed and validated a stimulator design that focuses on high construct capacity, compatibility with tissue culture plastic ware, and regimen adaptability to maximize throughput. This design utilizes thin force sensors in lieu of a load cell and a linear encoder to verify position. The implementation of an individual force sensor for each sample enables the measurement of Young's modulus while stimulating the sample. Removable and interchangeable Teflon plungers mounted using neodymium magnets contact each sample. Variations in plunger height and design can vary the strain and force type on individual samples. This allows for the evaluation of a myriad of culture conditions and regimens simultaneously. The system was validated using contact accuracy, and Young's modulus measurements range as key parameters. Contact accuracy for the system was excellent within 1.16% error of the construct height in comparison to measurements made with a micrometer. Biomaterials ranging from bioceramics (cancellous bone, 123 MPa) to soft gels (1% agarose, 20 KPa) can be measured without any modification to the device. The accuracy of measurements in conjunction with the wide range of moduli tested demonstrate the unique characteristics of the device and the feasibility of using this device in mapping real-time changes to Young's modulus of tissue constructs (cartilage, bone) through the developmental phases in ex vivo culture conditions. PMID:21988089

Interactions Between Adrenal and Calcium-Regulatory Hormones in Human Health

PubMed Central

Brown, Jenifer M.; Vaidya, Anand

2014-01-01

Purpose of Review To summarize evidence characterizing the interactions between adrenal- and calcium-regulating hormones, and the relevance of these interactions to human cardiovascular and skeletal health. Recent Findings Human studies support the regulation of parathyroid hormone (PTH) by the renin-angiotensin-aldosterone system (RAAS): angiotensin II may stimulate PTH secretion via an acute and direct mechanism, whereas aldosterone may exert a chronic stimulation of PTH secretion. Studies in primary aldosteronism, congestive heart failure, and chronic kidney disease have identified associations between hyperaldosteronism, hyperparathyroidism, and bone loss, which appear to improve when inhibiting the RAAS. Conversely, elevated PTH and insufficient vitamin D status have been associated with adverse cardiovascular outcomes, which may be mediated by the RAAS. Studies of primary hyperparathyroidism implicate PTH-mediated stimulation of the RAAS, and recent evidence shows that the vitamin D-vitamin D receptor (VDR) complex may negatively regulate renin expression and RAAS activity. Ongoing human interventional studies are evaluating the influence of RAAS inhibition on PTH and the influence of VDR agonists on RAAS activity. Summary While previously considered independent endocrine systems, emerging evidence supports a complex web of interactions between adrenal and calcium-regulating hormones, with implications for human cardiovascular and skeletal health. PMID:24694551

Chitosan nanofiber scaffold improves bone healing via stimulating trabecular bone production due to upregulation of the Runx2/osteocalcin/alkaline phosphatase signaling pathway

PubMed Central

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

The synergistic effect on osteogenic differentiation of human mesenchymal stem cells by diode laser-treated stimulating human umbilical vein endothelial cells

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.

Prostaglandin E2 Prevents Bone Loss and Adds Extra Bone to Immobilized Distal Femoral Metaphysis in Female Rats

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.

Bone healing in 2016

PubMed Central

Buza, John A.; Einhorn, Thomas

2016-01-01

Summary Delayed fracture healing and nonunion occurs in up to 5–10% of all fractures, and can present a challenging clinical scenario for the treating physician. Methods for the enhancement of skeletal repair may benefit patients that are at risk of, or have experienced, delayed healing or nonunion. These methods can be categorized into either physical stimulation therapies or biological therapies. Physical stimulation therapies include electrical stimulation, low-intensity pulsed ultrasonography, or extracorporeal shock wave therapy. Biological therapies can be further classified into local or systemic therapy based on the method of delivery. Local methods include autologous bone marrow, autologous bone graft, fibroblast growth factor-2, platelet-rich plasma, platelet-derived growth factor, and bone morphogenetic proteins. Systemic therapies include parathyroid hormone and bisphosphonates. This article reviews the current applications and supporting evidence for the use of these therapies in the enhancement of fracture healing. PMID:27920804

CB2 Cannabinoid Receptor Targets Mitogenic Gi Protein–Cyclin D1 Axis in Osteoblasts

PubMed Central

Ofek, Orr; Attar-Namdar, Malka; Kram, Vardit; Dvir-Ginzberg, Mona; Mechoulam, Raphael; Zimmer, Andreas; Frenkel, Baruch; Shohami, Esther; Bab, Itai

2011-01-01

CB2 is a Gi protein–coupled receptor activated by endo- and phytocannabinoids, thus inhibiting stimulated adenylyl cyclase activity. CB2 is expressed in bone cells and Cb2 null mice show a marked age-related bone loss. CB2-specific agonists both attenuate and rescue ovariectomy-induced bone loss. Activation of CB2 stimulates osteoblast proliferation and bone marrow derived colony-forming units osteoblastic. Here we show that selective and nonselective CB2 agonists are mitogenic in MC3T3 E1 and newborn mouse calvarial osteoblastic cultures. The CB2 mitogenic signaling depends critically on the stimulation of Erk1/2 phosphorylation and de novo synthesis of MAP kinase–activated protein kinase 2 (Mapkapk2) mRNA and protein. Further downstream, CB2 activation enhances CREB transcriptional activity and cyclin D1 mRNA expression. The CB2-induced stimulation of CREB and cyclin D1 is inhibitable by pertussis toxin, the MEK-Erk1/2 inhibitors PD098059 and U0126, and Mapkapk2 siRNA. These data demonstrate that in osteoblasts CB2 targets a Gi protein–cyclin D1 mitogenic axis. Erk1/2 phosphorylation and Mapkapk2 protein synthesis are critical intermediates in this axis. © 2011 American Society for Bone and Mineral Research. PMID:20803555

Negative regulation of BMP signaling by the ski oncoprotein.

PubMed

Luo, Kunxin

2003-01-01

The bone morphogenetic proteins (BMPs) play important roles in the regulation of multiple aspects of vertebrate development. BMPs signal through the cell surface receptors and downstream Smad molecules. Upon stimulation with BMP, Smad1, Smad5, and Smad8 are phosphorylated by the activated BMP receptors, form a complex with Smad4, and translocate into the nucleus, where they regulate the expression of BMP target genes. The activity of this signal pathway can be modulated both by extracellular factors that regulate the binding of BMPs to the receptor and by intracellular proteins that interact with the Smad proteins. We have shown that Ski is an important negative regulator of the Smad proteins. Ski can bind to the BMP-Smad protein complexes in response to BMP and repress their ability to activate BMP target genes through disruption of a functional Smad complex and through recruitment of transcriptional co-repressors. The antagonism of BMP signaling by Ski results in neural specification in Xenopus embryos and inhibition of osteoblast differentiation in mouse bone-marrow stromal progenitor cells. This ability to modulate BMP signaling by Ski may play an important role in the regulation of craniofacial, neuronal, and skeletal muscle development.

Rehabilitation and return-to-sports activity after debridement and bone marrow stimulation of osteochondral talar defects.

PubMed

van Eekeren, Inge C M; Reilingh, Mikel L; van Dijk, C Niek

2012-10-01

An osteochondral defect (OD) is a lesion involving the articular cartilage and the underlying subchondral bone. ODs of the talus can severely impact on the quality of life of patients, who are usually young and athletic. The primary treatment for ODs that are too small for fixation, consists of arthroscopic debridement and bone marrow stimulation. This article delineates levels of activity, determines times for return to activity and reviews the factors that affect rehabilitation after arthroscopic debridement and bone marrow stimulation of a talar OD. Articles for review were obtained from a search of the MEDLINE database up to January 2012 using the search headings 'osteochondral defects', 'bone marrow stimulation', 'sports/activity', 'rehabilitation', various other related factors and 'talus'. English-, Dutch- and German-language studies were evaluated.The review revealed that there is no consensus in the existing literature about rehabilitation times or return-to-sports activity times, after treatment with bone marrow stimulation of ODs in the talus. Furthermore, scant research has been conducted on these issues. The literature also showed that potential factors that aid rehabilitation could include youth, lower body mass index, smaller OD size, mobilization and treatment with growth factors, platelet-rich plasma, biphosphonates, hyaluronic acid and pulse electromagnetic fields. However, most studies have been conducted in vitro or on animals. We propose a scheme, whereby return-to-sports activity is divided into four phases of increasing intensity: walking, jogging, return to non-contact sports (running without swerving) and return to contact sports (running with swerving and collision). We also recommend that research, conducted on actual sportsmen, of recovery times after treatment of talar ODs is warranted.

Development and Characterization of Organic Electronic Scaffolds for Bone Tissue Engineering.

PubMed

Iandolo, Donata; Ravichandran, Akhilandeshwari; Liu, Xianjie; Wen, Feng; Chan, Jerry K Y; Berggren, Magnus; Teoh, Swee-Hin; Simon, Daniel T

2016-06-01

Bones have been shown to exhibit piezoelectric properties, generating electrical potential upon mechanical deformation and responding to electrical stimulation with the generation of mechanical stress. Thus, the effects of electrical stimulation on bone tissue engineering have been extensively studied. However, in bone regeneration applications, only few studies have focused on the use of electroactive 3D biodegradable scaffolds at the interphase with stem cells. Here a method is described to combine the bone regeneration capabilities of 3D-printed macroporous medical grade polycaprolactone (PCL) scaffolds with the electrical and electrochemical capabilities of the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT). PCL scaffolds have been highly effective in vivo as bone regeneration grafts, and PEDOT is a leading material in the field of organic bioelectronics, due to its stability, conformability, and biocompatibility. A protocol is reported for scaffolds functionalization with PEDOT, using vapor-phase polymerization, resulting in a conformal conducting layer. Scaffolds' porosity and mechanical stability, important for in vivo bone regeneration applications, are retained. Human fetal mesenchymal stem cells proliferation is assessed on the functionalized scaffolds, showing the cytocompatibility of the polymeric coating. Altogether, these results show the feasibility of the proposed approach to obtain electroactive scaffolds for electrical stimulation of stem cells for regenerative medicine. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Actin-Sorting Nexin 27 (SNX27)-Retromer Complex Mediates Rapid Parathyroid Hormone Receptor Recycling*

PubMed Central

McGarvey, Jennifer C.; Xiao, Kunhong; Bowman, Shanna L.; Mamonova, Tatyana; Zhang, Qiangmin; Bisello, Alessandro; Sneddon, W. Bruce; Ardura, Juan A.; Jean-Alphonse, Frederic; Vilardaga, Jean-Pierre; Puthenveedu, Manojkumar A.; Friedman, Peter A.

2016-01-01

The G protein-coupled parathyroid hormone receptor (PTHR) regulates mineral-ion homeostasis and bone remodeling. Upon parathyroid hormone (PTH) stimulation, the PTHR internalizes into early endosomes and subsequently traffics to the retromer complex, a sorting platform on early endosomes that promotes recycling of surface receptors. The C terminus of the PTHR contains a type I PDZ ligand that binds PDZ domain-containing proteins. Mass spectrometry identified sorting nexin 27 (SNX27) in isolated endosomes as a PTHR binding partner. PTH treatment enriched endosomal PTHR. SNX27 contains a PDZ domain and serves as a cargo selector for the retromer complex. VPS26, VPS29, and VPS35 retromer subunits were isolated with PTHR in endosomes from cells stimulated with PTH. Molecular dynamics and protein binding studies establish that PTHR and SNX27 interactions depend on the PDZ recognition motif in PTHR and the PDZ domain of SNX27. Depletion of either SNX27 or VPS35 or actin depolymerization decreased the rate of PTHR recycling following agonist stimulation. Mutating the PDZ ligand of PTHR abolished the interaction with SNX27 but did not affect the overall rate of recycling, suggesting that PTHR may directly engage the retromer complex. Coimmunoprecipitation and overlay experiments show that both intact and mutated PTHR bind retromer through the VPS26 protomer and sequentially assemble a ternary complex with PTHR and SNX27. SNX27-independent recycling may involve N-ethylmaleimide-sensitive factor, which binds both PDZ intact and mutant PTHRs. We conclude that PTHR recycles rapidly through at least two pathways, one involving the ASRT complex of actin, SNX27, and retromer and another possibly involving N-ethylmaleimide-sensitive factor. PMID:27008860

Treatment with at Homeopathic Complex Medication Modulates Mononuclear Bone Marrow Cell Differentiation

PubMed Central

Cesar, Beatriz; Abud, Ana Paula R.; de Oliveira, Carolina C.; Cardoso, Francolino; Bernardi, Raffaello Popa Di; Guimarães, Fernando S. F.; Gabardo, Juarez; de Freitas Buchi, Dorly

2011-01-01

A homeopathic complex medication (HCM), with immunomodulatory properties, is recommended for patients with depressed immune systems. Previous studies demonstrated that the medication induces an increase in leukocyte number. The bone marrow microenvironment is composed of growth factors, stromal cells, an extracellular matrix and progenitor cells that differentiate into mature blood cells. Mice were our biological model used in this research. We now report in vivo immunophenotyping of total bone marrow cells and ex vivo effects of the medication on mononuclear cell differentiation at different times. Cells were examined by light microscopy and cytokine levels were measured in vitro. After in vivo treatment with HCM, a pool of cells from the new marrow microenvironment was analyzed by flow cytometry to detect any trend in cell alteration. The results showed decreases, mainly, in CD11b and TER-119 markers compared with controls. Mononuclear cells were used to analyze the effects of ex vivo HCM treatment and the number of cells showing ring nuclei, niche cells and activated macrophages increased in culture, even in the absence of macrophage colony-stimulating factor. Cytokines favoring stromal cell survival and differentiation in culture were induced in vitro. Thus, we observe that HCM is immunomodulatory, either alone or in association with other products. PMID:19736221

Regulation of proliferation of rat cartilage and bone by sex steroid hormones.

PubMed

Sömjen, D; Weisman, Y; Mor, Z; Harell, A; Kaye, A M

1991-01-01

We have demonstrated previously that 17 beta-estradiol (E2) stimulates proliferation of skeletal tissues, both in vivo and in vitro, as measured by increased DNA synthesis and creatine kinase (CK) specific activity. The effect of E2 on bone is sex specific. E2 is active only in females and androgens only in males. By contrast, in cartilage of both sexes, dihydrotestosterone (DHT) as well as E2 stimulates CK specific activity and DNA synthesis. In bone, we find that sex steroids stimulate skeletal cell proliferation in gonadectomized as well as in immature rats. Ovariectomized (OVX) rats, between 1 and 4 weeks after surgery, show stimulation of CK by E2. The basal activity and response of CK changes with the varying endogenous levels of E2 in cycling rats, in which the highest basal activity is at proestrus and estrus and the highest response is in diestrus. In rats of all ages tested, both the basal and stimulated specific activity of CK is higher in diaphysis and epiphysis than in the uterus, or in the adipose tissue adjacent to the uterus, which has a response similar to that of the uterus itself. The effect of E2 in vivo, and in chrondroblasts and osteoblasts in vitro, is inhibited by high levels of the antiestrogen tamoxifen which, by itself, in similar high concentrations, shows stimulatory effects. In addition to the sex steroids, skeletal cells are also stimulated by secosteroid and peptide calciotrophic hormones. The interactions of the sex steroids with these hormones modulate the response of cartilage and bone cells to both sex steroids and the other calciotrophic hormones. These results provide the first steps towards understanding the regulation of bone cell proliferation and growth by the concerted action of a variety of hormones and growth factors.

Endothelin-1 regulates rat bone sialoprotein gene transcription.

PubMed

Li, Xinyue; Wang, Zhitao; Yang, Li; Li, Zhengyang; Ogata, Yorimasa

2010-06-01

Endothelin-1 (ET-1) was originally discovered as a vasoconstrictor protein excreted by vascular endothelial cells. Recently, tumor-produced ET-1 has been considered to stimulate osteoblasts to form new bone, and to be an important mediator of osteoblastic bone metastasis. ET-1 has high affinity for two different membrane receptors, ET(A)R and ET(B)R, which are expressed by many types of cells including osteoblasts. Bone sialoprotein (BSP) is a phosphorylated and sulfated glycoprotein associated with mineralized connective tissues. To investigate the effects of ET-1 on BSP transcription, we used rat osteoblast-like ROS17/2.8 cells. Levels of BSP and osteopontin mRNA were increased at 12 h after treatment with ET-1 (10 ng/ml), and ET-1 at the same concentration induced luciferase activity of a -116 to +60 BSP promoter construct at 6 h. Transcriptional activity of -84BSPLUC, which contains the cAMP response element (CRE), was increased by ET-1. Furthermore, at 6 h, ET-1 (10 ng/ml) increased the binding of nuclear protein to CRE, the FGF2 response element (FRE) and the homeodomain protein-binding site (HOX). Antibodies against CREB1, JunD and Fra2 disrupted the formation of CRE-protein complexes, while antibodies against Runx2 and Dlx5 reduced the formation of FRE- and HOX-protein complexes. These findings indicate that ET-1 increases BSP transcription via the CRE, FRE and HOX sites in the rat BSP gene promoter.

Postnatal ablation of osteoblast Smad4 enhances proliferative responses to canonical Wnt signaling through interactions with β-catenin

PubMed Central

Salazar, Valerie S.; Zarkadis, Nicholas; Huang, Lisa; Watkins, Marcus; Kading, Jacqueline; Bonar, Sheri; Norris, Jin; Mbalaviele, Gabriel; Civitelli, Roberto

2013-01-01

Summary Canonical Wnt (cWnt) signaling through β-catenin regulates osteoblast proliferation and differentiation to enhance bone formation. We previously reported that osteogenic action of β-catenin is dependent on BMP signaling. Here, we further examined interactions between cWnt and BMP in bone. In osteoprogenitors stimulated with BMP2, β-catenin localizes to the nucleus, physically interacts with Smad4, and is recruited to DNA-binding transcription complexes containing Smad4, R-Smad1/5 and TCF4. Furthermore, Tcf/Lef-dependent transcription, Ccnd1 expression and proliferation all increase when Smad4, 1 or 5 levels are low, whereas TCF/Lef activities decrease when Smad4 expression is high. The ability of Smad4 to antagonize transcription of Ccnd1 is dependent on DNA-binding activity but Smad4-dependent transcription is not required. In mice, conditional deletion of Smad4 in osterix+ cells increases mitosis of cells on trabecular bone surfaces as well as in primary osteoblast cultures from adult bone marrow and neonatal calvaria. By contrast, ablation of Smad4 delays differentiation and matrix mineralization by primary osteoblasts in response to Wnt3a, indicating that loss of Smad4 perturbs the balance between proliferation and differentiation in osteoprogenitors. We propose that Smad4 and Tcf/Lef transcription complexes compete for β-catenin, thus restraining cWnt-dependent proliferative signals while favoring the matrix synthesizing activity of osteoblasts. PMID:24101723

Treatment with eldecalcitol positively affects mineralization, microdamage, and collagen crosslinks in primate bone.

PubMed

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.

Maternal embryonic leucine zipper kinase inhibitor OTSSP167 has preclinical activity on multiple myeloma bone disease.

PubMed

Muller, Joséphine; Bolomsky, Arnold; Dubois, Sophie; Duray, Elodie; Stangelberger, Kathrin; Plougonven, Erwan; Lejeune, Margaux; Léonard, Angélique; Marty, Caroline; Hempel, Ute; Baron, Frédéric; Beguin, Yves; Cohen-Solal, Martine; Ludwig, Heinz; Heusschen, Roy; Caers, Jo

2018-05-10

Multiple myeloma bone disease is characterized by an uncoupling of bone remodeling in the multiple myeloma microenvironment, resulting in the development of lytic bone lesions. Most myeloma patients suffer from these bone lesions, which not only causes morbidity but also negatively impacts survival. The development of novel therapies, ideally with a combined anti-resorptive and bone-anabolic effect, is of great interest because lesions persist with the current standard of care, even in patients in complete remission. We have previously shown that MELK plays a central role in proliferation-associated high-risk multiple myeloma and its inhibition with OTSSP167 resulted in decreased tumor load. MELK inhibition in bone cells has not yet been explored, although some reports suggest factors downstream of MELK stimulate osteoclast activity and inhibit osteoblast activity, which makes MELK inhibition a promising therapeutic approach. Therefore, we assessed the effect of OTSSP167 on bone cell activity and the development of myeloma-induced bone disease. OTSSP167 inhibited osteoclast activity in vitro by decreasing progenitor viability as well as via a direct anti-resorptive effect on mature osteoclasts. In addition, OTSSP167 stimulated matrix deposition and mineralization by osteoblasts in vitro. This combined anti-resorptive and osteoblast-stimulating effect of OTSSP167 resulted in the complete prevention of lytic lesions and bone loss in myeloma-bearing mice. Immunohistomorphometric analyses corroborated our in vitro findings. In conclusion, we show that OTSSP167 has a direct effect on myeloma-induced bone disease in addition to its anti-multiple myeloma effect, which warrants further clinical development of MELK inhibition in multiple myeloma. Copyright © 2018, Ferrata Storti Foundation.

Regulation of bone formation by osteoclasts involves Wnt/BMP signaling and the chemokine sphingosine-1-phosphate

PubMed Central

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

Early detection of disease program: Evaluation of the cellular immune response

NASA Technical Reports Server (NTRS)

Criswell, B. S.; Knight, V.; Martin, R. R.; Kasel, J. A.

1975-01-01

Surfaces of normal, cultured, and mitogen-stimulated mouse lymphoid cells were examined by scanning electron microscopy (SEM). Lymphocytes with smooth, highly villous and intermediate surfaces were observed in cell suspensions from both spleens and thymuses of normal mice and from spleens of congenitally athymic (nude) mice. Several strain-specific surface features were noted, including the spine-like appearance of microvilli on C57B1/6 lymphocytes. Although thymus cell suspensions contained somewhat more smooth cells than did spleen cell preparations, lymphocyte derivation could not be inferred from SEM examination. Studies of cells stimulated with mitogenic agents for thymus-derived lymphocytes (concanavalin A) or for bone marrow-derived lymphocytes (lipopolysaccharide) suggested that, in the mouse, development of a complex villous surface is a general concomitant of lymphocyte activation and transformation.

Anabolic activity of ursolic acid in bone: Stimulating osteoblast differentiation in vitro and inducing new bone formation in vivo.

PubMed

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.

Osteoblast and osteocyte: games without frontiers.

PubMed

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.

Stimulating Fracture Healing in Ischemic Environments: Does Oxygen Direct Stem Cell Fate during Fracture Healing?

PubMed Central

Miclau, Katherine R.; Brazina, Sloane A.; Bahney, Chelsea S.; Hankenson, Kurt D.; Hunt, Thomas K.; Marcucio, Ralph S.; Miclau, Theodore

2017-01-01

Bone fractures represent an enormous societal and economic burden as one of the most prevalent causes of disability worldwide. Each year, nearly 15 million people are affected by fractures in the United States alone. Data indicate that the blood supply is critical for fracture healing; as data indicate that concomitant bone and vascular injury are major risk factors for non-union. However, the various role(s) that the vasculature plays remains speculative. Fracture stabilization dictates stem cell fate choices during repair. In stabilized fractures stem cells differentiate directly into osteoblasts and heal the injury by intramembranous ossification. In contrast, in non-stable fractures stem cells differentiate into chondrocytes and the bone heals through endochondral ossification, where a cartilage template transforms into bone as the chondrocytes transform into osteoblasts. One suggested role of the vasculature has been to participate in the stem cell fate decisions due to delivery of oxygen. In stable fractures, the blood vessels are thought to remain intact and promote osteogenesis, while in non-stable fractures, continual disruption of the vasculature creates hypoxia that favors formation of cartilage, which is avascular. However, recent data suggests that non-stable fractures are more vascularized than stable fractures, that oxygen does not appear associated with differentiation of stem cells into chondrocytes and osteoblasts, that cartilage is not hypoxic, and that oxygen, not sustained hypoxia, is required for angiogenesis. These unexpected results, which contrast other published studies, are indicative of the need to better understand the complex, spatio-temporal regulation of vascularization and oxygenation in fracture healing. This work has also revealed that oxygen, along with the promotion of angiogenesis, may be novel adjuvants that can stimulate healing in select patient populations. PMID:28523266

Hypervitaminosis A and bone.

PubMed

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.

Heterogeneity Within Macrophage Populations: A Possible Role for Colony Stimulating Factors

DTIC Science & Technology

1988-04-04

highest concentration ofriFN-yused (5.0 U/ml), a depression of T cell proliferation induced by the antigen-pulsed rGM-CSF-derived macrophages was...stimulation by rGM-CSF and nCSF-1 in bone marrow cells derived from normal mice and mice 3 and 7 days post-treatment with 5FU . Bone marrow cells

Reprogramming the Metastatic Microenvironment to Combat Disease Recurrence

DTIC Science & Technology

2016-10-01

the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this...lead to pathological bone loss, which can stimulate tumor cell outgrowth. In addition to contributing to morbidity, this ‘vicious cycle’ also...surveillance and antigen presentation affect metastatic relapse in the bone. In so doing, we discovered that inhibiting colony stimulating factor-1

Wedelolactone enhances osteoblastogenesis by regulating Wnt/β-catenin signaling pathway but suppresses osteoclastogenesis by NF-κB/c-fos/NFATc1 pathway.

PubMed

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.

Bone marrow stimulation of the medial femoral condyle produces inferior cartilage and bone repair compared to the trochlea in a rabbit surgical model.

PubMed

Chen, Hongmei; Chevrier, Anik; Hoemann, Caroline D; Sun, Jun; Picard, Genevieve; Buschmann, Michael D

2013-11-01

The influence of the location of cartilage lesions on cartilage repair outcome is incompletely understood. This study compared cartilage and bone repair in medial femoral condylar (MFC) versus femoral trochlear (TR) defects 3 months after bone marrow stimulation in mature rabbits. Intact femurs from adult rabbits served as controls. Results from quantitative histomorphometry and histological scoring showed that bone marrow stimulation produced inferior soft tissue repair in MFC versus TR defects, as indicated by significantly lower % Fill (p = 0.03), a significant increase in collagen type I immunostaining (p < 0.00001) and lower O'Driscoll scores (p < 0.05). 3D micro-CT analysis showed that repaired TR defects regained normal un-operated values of bone volume fraction, trabecular thickness, and trabecular number, whereas in MFC defects the repaired bone architecture appeared immature and less dense compared to intact un-operated MFC controls (p < 0.0001). Severe medial meniscal damage was found in 28% of operated animals and was strongly correlated with (i) low cartilage defect fill, (ii) incomplete bone repair in MFC, and (iii) with a more posterior defect placement in the weight-bearing region. We conclude that the location of cartilage lesions influences cartilage repair, with better outcome in TR versus MFC defects in rabbits. Meniscal degeneration is associated with cartilage damage. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

The G-factor as a tool to learn more about bone structure and function.

PubMed

Zerath, E

1999-07-01

In normal life on earth, the locomotor system is exposed to two types of stimulation: gravity (passive stimulation) and motion (active stimulation). Both permanently combine, and the interactions between locomotion and gravity induce an overall recruitment which is repeated daily and maintains the bone tissue structure within the range of constraints to which it is adapted. This range is one of the basic hypotheses underlying the mechanical concepts of bone structure control, and it has been considered as logical to assume that weightlessness of spaceflight should produce bone loss since astronauts are outside of the terrestrial gravitational field of forces, no longer relying on muscular work to change positions or move. But, thirty years after the first changes in phospho-calcium metabolism were observed in astronauts after spaceflight, current knowledge does not provide a full understanding of this pathogeny, and prove the G-factor is now considered as an essential component of the experimental tools available to study bone physiology. The study of the physiology of bone tissue usually consists in the investigation of its two fundamental roles, i.e. reservoir of inorganic elements (calcium, phosphorus, magnesium) and mechanical support for soft tissues. Together with the combined action of muscles, tendons, and ligaments, this support permits motion and locomotion. These two functions rely on a sophisticated bone tissue architecture, and on the adaptability of this structure, with modeling and remodeling processes, themselves associated with the coupled activity of specialized bone cell populations.

Modeling Hematopoiesis and Responses to Radiation Countermeasures in a Bone Marrow-on-a-Chip.

PubMed

Torisawa, Yu-Suke; Mammoto, Tadanori; Jiang, Elisabeth; Jiang, Amanda; Mammoto, Akiko; Watters, Alexander L; Bahinski, Anthony; Ingber, Donald E

2016-05-01

Studies on hematopoiesis currently rely on animal models because in vitro culture methods do not accurately recapitulate complex bone marrow physiology. We recently described a bone marrow-on-a-chip microfluidic device that enables the culture of living hematopoietic bone marrow and mimics radiation toxicity in vitro. In the present study, we used this microdevice to demonstrate continuous blood cell production in vitro and model bone marrow responses to potential radiation countermeasure drugs. The device maintained mouse hematopoietic stem and progenitor cells in normal proportions for at least 2 weeks in culture. Increases in the number of leukocytes and red blood cells into the microfluidic circulation also could be detected over time, and addition of erythropoietin induced a significant increase in erythrocyte production. Exposure of the bone marrow chip to gamma radiation resulted in reduction of leukocyte production, and treatment of the chips with two potential therapeutics, granulocyte-colony stimulating factor or bactericidal/permeability-increasing protein (BPI), induced significant increases in the number of hematopoietic stem cells and myeloid cells in the fluidic outflow. In contrast, BPI was not found to have any effect when analyzed using static marrow cultures, even though it has been previously shown to accelerate recovery from radiation-induced toxicity in vivo. These findings demonstrate the potential value of the bone marrow-on-a-chip for modeling blood cell production, monitoring responses to hematopoiesis-modulating drugs, and testing radiation countermeasures in vitro.

The effect of cationically-modified phosphorylcholine polymers on human osteoblasts in vitro and their effect on bone formation in vivo.

PubMed

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.

Ski represses bone morphogenic protein signaling in Xenopus and mammalian cells

PubMed Central

Wang, Wei; Mariani, Francesca V.; Harland, Richard M.; Luo, Kunxin

2000-01-01

The bone morphogenic proteins (BMPs) play important roles in vertebrate development. In Xenopus, BMPs act as epidermal inducers and also as negative regulators of neurogenesis. Antagonism of BMP signaling results in neuralization. BMPs signal through the cell-surface receptors and downstream Smad molecules. Upon stimulation with BMP, Smad1, Smad5, and Smad8 are phosphorylated by the activated BMP receptors, form a complex with Smad4, and translocate into the nucleus, where they regulate the expression of BMP target genes. Here, we show that the Ski oncoprotein can block BMP signaling and the expression of BMP-responsive genes in both Xenopus and mammalian cells by directly interacting with and repressing the activity of BMP-specific Smad complexes. This ability to antagonize BMP signaling results in neuralization by Ski in the Xenopus embryo and blocking of osteoblast differentiation of murine W-20-17 cells. Thus, Ski is able to repress the activity of all receptor-associated Smads and may regulate vertebrate development by modulating the signaling activity of transforming growth factor-β family members. PMID:11121043

Ski represses bone morphogenic protein signaling in Xenopus and mammalian cells.

PubMed

Wang, W; Mariani, F V; Harland, R M; Luo, K

2000-12-19

The bone morphogenic proteins (BMPs) play important roles in vertebrate development. In Xenopus, BMPs act as epidermal inducers and also as negative regulators of neurogenesis. Antagonism of BMP signaling results in neuralization. BMPs signal through the cell-surface receptors and downstream Smad molecules. Upon stimulation with BMP, Smad1, Smad5, and Smad8 are phosphorylated by the activated BMP receptors, form a complex with Smad4, and translocate into the nucleus, where they regulate the expression of BMP target genes. Here, we show that the Ski oncoprotein can block BMP signaling and the expression of BMP-responsive genes in both Xenopus and mammalian cells by directly interacting with and repressing the activity of BMP-specific Smad complexes. This ability to antagonize BMP signaling results in neuralization by Ski in the Xenopus embryo and blocking of osteoblast differentiation of murine W-20-17 cells. Thus, Ski is able to repress the activity of all receptor-associated Smads and may regulate vertebrate development by modulating the signaling activity of transforming growth factor-beta family members.

Dynamic hydraulic fluid stimulation regulated intramedullary pressure.

PubMed

Hu, Minyi; Serra-Hsu, Frederick; Bethel, Neville; Lin, Liangjun; Ferreri, Suzanne; Cheng, Jiqi; Qin, Yi-Xian

2013-11-01

Physical signals within the bone, i.e. generated from mechanical loading, have the potential to initiate skeletal adaptation. Strong evidence has pointed to bone fluid flow (BFF) as a media between an external load and the bone cells, in which altered velocity and pressure can ultimately initiate the mechanotransduction and the remodeling process within the bone. Load-induced BFF can be altered by factors such as intramedullary pressure (ImP) and/or bone matrix strain, mediating bone adaptation. Previous studies have shown that BFF induced by ImP alone, with minimum bone strain, can initiate bone remodeling. However, identifying induced ImP dynamics and bone strain factor in vivo using a non-invasive method still remains challenging. To apply ImP as a means for alteration of BFF, it was hypothesized that non-invasive dynamic hydraulic stimulation (DHS) can induce local ImP with minimal bone strain to potentially elicit osteogenic adaptive responses via bone-muscle coupling. The goal of this study was to evaluate the immediate effects on local and distant ImP and strain in response to a range of loading frequencies using DHS. Simultaneous femoral and tibial ImP and bone strain values were measured in three 15-month-old female Sprague Dawley rats during DHS loading on the tibia with frequencies of 1Hz to 10Hz. DHS showed noticeable effects on ImP induction in the stimulated tibia in a nonlinear fashion in response to DHS over the range of loading frequencies, where they peaked at 2Hz. DHS at various loading frequencies generated minimal bone strain in the tibiae. Maximal bone strain measured at all loading frequencies was less than 8με. No detectable induction of ImP or bone strain was observed in the femur. This study suggested that oscillatory DHS may regulate the local fluid dynamics with minimal mechanical strain in the bone, which serves critically in bone adaptation. These results clearly implied DHS's potential as an effective, non-invasive intervention for osteopenia and osteoporosis treatments. © 2013. Published by Elsevier Inc. All rights reserved.

Piezoelectric materials as stimulatory biomedical materials and scaffolds for bone repair.

PubMed

Tandon, Biranche; Blaker, Jonny J; Cartmell, Sarah H

2018-04-16

The process of bone repair and regeneration requires multiple physiological cues including biochemical, electrical and mechanical - that act together to ensure functional recovery. Myriad materials have been explored as bioactive scaffolds to deliver these cues locally to the damage site, amongst these piezoelectric materials have demonstrated significant potential for tissue engineering and regeneration, especially for bone repair. Piezoelectric materials have been widely explored for power generation and harvesting, structural health monitoring, and use in biomedical devices. They have the ability to deform with physiological movements and consequently deliver electrical stimulation to cells or damaged tissue without the need of an external power source. Bone itself is piezoelectric and the charges/potentials it generates in response to mechanical activity are capable of enhancing bone growth. Piezoelectric materials are capable of stimulating the physiological electrical microenvironment, and can play a vital role to stimulate regeneration and repair. This review gives an overview of the association of piezoelectric effect with bone repair, and focuses on state-of-the-art piezoelectric materials (polymers, ceramics and their composites), the fabrication routes to produce piezoelectric scaffolds, and their application in bone repair. Important characteristics of these materials from the perspective of bone tissue engineering are highlighted. Promising upcoming strategies and new piezoelectric materials for this application are presented. Electrical stimulation/electrical microenvironment are known effect the process of bone regeneration by altering the cellular response and are crucial in maintaining tissue functionality. Piezoelectric materials, owing to their capability of generating charges/potentials in response to mechanical deformations, have displayed great potential for fabricating smart stimulatory scaffolds for bone tissue engineering. The growing interest of the scientific community and compelling results of the published research articles has been the motivation of this review article. This article summarizes the significant progress in the field with a focus on the fabrication aspects of piezoelectric materials. The review of both material and cellular aspects on this topic ensures that this paper appeals to both material scientists and tissue engineers. Copyright © 2018. Published by Elsevier Ltd.

σ2-Adaptin Facilitates Basal Synaptic Transmission and Is Required for Regenerating Endo-Exo Cycling Pool Under High-Frequency Nerve Stimulation in Drosophila.

PubMed

Choudhury, Saumitra Dey; Mushtaq, Zeeshan; Reddy-Alla, Suneel; Balakrishnan, Sruthi S; Thakur, Rajan S; Krishnan, Kozhalmannom S; Raghu, Padinjat; Ramaswami, Mani; Kumar, Vimlesh

2016-05-01

The functional requirement of adapter protein 2 (AP2) complex in synaptic membrane retrieval by clathrin-mediated endocytosis is not fully understood. Here we isolated and functionally characterized a mutation that dramatically altered synaptic development. Based on the aberrant neuromuscular junction (NMJ) synapse, we named this mutation angur (a Hindi word meaning "grapes"). Loss-of-function alleles of angur show more than twofold overgrowth in bouton numbers and a dramatic decrease in bouton size. We mapped the angur mutation to σ2-adaptin, the smallest subunit of the AP2 complex. Reducing the neuronal level of any of the subunits of the AP2 complex or disrupting AP2 complex assembly in neurons phenocopied the σ2-adaptin mutation. Genetic perturbation of σ2-adaptin in neurons leads to a reversible temperature-sensitive paralysis at 38°. Electrophysiological analysis of the mutants revealed reduced evoked junction potentials and quantal content. Interestingly, high-frequency nerve stimulation caused prolonged synaptic fatigue at the NMJs. The synaptic levels of subunits of the AP2 complex and clathrin, but not other endocytic proteins, were reduced in the mutants. Moreover, bone morphogenetic protein (BMP)/transforming growth factor β (TGFβ) signaling was altered in these mutants and was restored by normalizing σ2-adaptin in neurons. Thus, our data suggest that (1) while σ2-adaptin facilitates synaptic vesicle (SV) recycling for basal synaptic transmission, its activity is also required for regenerating SVs during high-frequency nerve stimulation, and (2) σ2-adaptin regulates NMJ morphology by attenuating TGFβ signaling. Copyright © 2016 by the Genetics Society of America.

Novel curcumin analogue UBS109 potently stimulates osteoblastogenesis and suppresses osteoclastogenesis: involvement in Smad activation and NF-κB inhibition.

PubMed

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.

Chip-based comparison of the osteogenesis of human bone marrow- and adipose tissue-derived mesenchymal stem cells under mechanical stimulation.

PubMed

Park, Sang-Hyug; Sim, Woo Young; Min, Byoung-Hyun; Yang, Sang Sik; Khademhosseini, Ali; Kaplan, David L

2012-01-01

Adipose tissue-derived stem cells (ASCs) are considered as an attractive stem cell source for tissue engineering and regenerative medicine. We compared human bone marrow-derived mesenchymal stem cells (hMSCs) and hASCs under dynamic hydraulic compression to evaluate and compare osteogenic abilities. A novel micro cell chip integrated with microvalves and microscale cell culture chambers separated from an air-pressure chamber was developed using microfabrication technology. The microscale chip enables the culture of two types of stem cells concurrently, where each is loaded into cell culture chambers and dynamic compressive stimulation is applied to the cells uniformly. Dynamic hydraulic compression (1 Hz, 1 psi) increased the production of osteogenic matrix components (bone sialoprotein, oateopontin, type I collagen) and integrin (CD11b and CD31) expression from both stem cell sources. Alkaline phosphatase and Alrizarin red staining were evident in the stimulated hMSCs, while the stimulated hASCs did not show significant increases in staining under the same stimulation conditions. Upon application of mechanical stimulus to the two types of stem cells, integrin (β1) and osteogenic gene markers were upregulated from both cell types. In conclusion, stimulated hMSCs and hASCs showed increased osteogenic gene expression compared to non-stimulated groups. The hMSCs were more sensitive to mechanical stimulation and more effective towards osteogenic differentiation than the hASCs under these modes of mechanical stimulation.

Chip-Based Comparison of the Osteogenesis of Human Bone Marrow- and Adipose Tissue-Derived Mesenchymal Stem Cells under Mechanical Stimulation

PubMed Central

Min, Byoung-Hyun; Yang, Sang Sik; Khademhosseini, Ali; Kaplan, David L.

2012-01-01

Adipose tissue-derived stem cells (ASCs) are considered as an attractive stem cell source for tissue engineering and regenerative medicine. We compared human bone marrow-derived mesenchymal stem cells (hMSCs) and hASCs under dynamic hydraulic compression to evaluate and compare osteogenic abilities. A novel micro cell chip integrated with microvalves and microscale cell culture chambers separated from an air-pressure chamber was developed using microfabrication technology. The microscale chip enables the culture of two types of stem cells concurrently, where each is loaded into cell culture chambers and dynamic compressive stimulation is applied to the cells uniformly. Dynamic hydraulic compression (1 Hz, 1 psi) increased the production of osteogenic matrix components (bone sialoprotein, oateopontin, type I collagen) and integrin (CD11b and CD31) expression from both stem cell sources. Alkaline phosphatase and Alrizarin red staining were evident in the stimulated hMSCs, while the stimulated hASCs did not show significant increases in staining under the same stimulation conditions. Upon application of mechanical stimulus to the two types of stem cells, integrin (β1) and osteogenic gene markers were upregulated from both cell types. In conclusion, stimulated hMSCs and hASCs showed increased osteogenic gene expression compared to non-stimulated groups. The hMSCs were more sensitive to mechanical stimulation and more effective towards osteogenic differentiation than the hASCs under these modes of mechanical stimulation. PMID:23029565

Effect of COX-2 (PGE2) and IL-6 on Prostate Cancer Bone Metastases

DTIC Science & Technology

2008-02-02

to stimulate both bone targeting and bone reaction (4). Several factors, such as basic fibroblast growth factor (4), osteocalcin, bone sialoprotein (8...Proc Natl Acad Sci U S A 1990;87:75–9. 8. Huang WC, Xie Z, Konaka H, Sodek J, Zhau HE, Chung LWK. Human osteocalcin and bone sialoprotein medi- ating

Mechanic stress generated by a time-varying electromagnetic field on bone surface.

PubMed

Ye, Hui

2018-03-19

Bone cells sense mechanical load, which is essential for bone growth and remodeling. In a fracture, this mechanism is compromised. Electromagnetic stimulation has been widely used to assist in bone healing, but the underlying mechanisms are largely unknown. A recent hypothesis suggests that electromagnetic stimulation could influence tissue biomechanics; however, a detailed quantitative understanding of EM-induced biomechanical changes in the bone is unavailable. This paper used a muscle/bone model to study the biomechanics of the bone under EM exposure. Due to the dielectric properties of the muscle/bone interface, a time-varying magnetic field can generate both compressing and shear stresses on the bone surface, where many mechanical sensing cells are available for cellular mechanotransduction. I calculated these stresses and found that the shear stress is significantly greater than the compressing stress. Detailed parametric analysis suggests that both the compressing and shear stresses are dependent on the geometrical and electrical properties of the muscle and the bone. These stresses are also functions of the orientation of the coil and the frequency of the magnetic field. It is speculated that the EM field could apply biomechanical influence to fractured bone, through the fine-tuning of the controllable field parameters. Graphical abstract Mechanic stress on bone surface in a time-varying magnetic field.

Using cell and organ culture models to analyze responses of bone cells to mechanical stimulation.

PubMed

Pitsillides, Andrew A; Rawlinson, Simon C F

2012-01-01

Bone cells of the osteoblastic lineage are responsive to the local mechanical environment. Through integration of a number of possible loading-induced regulatory stimuli, osteocyte, osteoblast, and osteoclast behaviour is organized to fashion a skeletal element of sufficient strength and toughness to resist fracture and crack propagation. Early pre-osteogenic responses had been determined in vivo and this led to the development of bone organ culture models to elucidate other pre-osteogenic responses where osteocytes and osteoblasts retain the natural orientation, connections and attachments to their native extracellular matrix. The application of physiological mechanical loads to bone in these organ culture models generates the regulatory stimuli. As a consequence, these experiments can be used to illustrate the distinctive mechanisms by which osteocytes and osteoblasts respond to mechanical loads and also differences in these responses, suggesting co-ordinated and cooperatively between cell populations. Organ explant cultures are awkward to maintain, and have a limited life, but length of culture times are improving. Monolayer cultures are much easier to maintain and permit the application of a particular mechanical stimulation to be studied in isolation; mainly direct mechanical strain or fluid shear strains. These allow for the response of a single cell type to the applied mechanical stimulation to be monitored precisely.The techniques that can be used to apply mechanical strain to bone and bone cells have not advanced greatly since the first edition. The output from such experiments has, however, increased substantially and their importance is now more broadly accepted. This suggests a growing use of these approaches and an increasing awareness of the importance of the mechanical environment in controlling normal bone cell behaviour. We expand the text to include additions and modifications made to the straining apparatus and update the research cited to support this growing role of cell and organ culture models to analyze responses of bone cells to mechanical stimulation.

Polymicrobial periodontal pathogens transcriptomes in calvarial bone and soft tissue

PubMed Central

Bakthavatchalu, Vasudevan; Meka, Archana; Mans, Jeffrey J.; Sathishkumar, Sabapathi; Lopez, M. Cecilia; Bhattacharyya, Indraneel; Boyce, Brendan F.; Baker, Henry V.; Lamont, Richard J.; Ebersole, Jeffrey L.; Kesavalu, L.

2011-01-01

Summary Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia are consistently associated with adult periodontitis. This study sought to document the host transcriptome to a P. gingivalis, T. denticola, and T. forsythia challenge as a polymicrobial infection using a murine calvarial model of acute inflammation and bone resorption. Mice were infected with P. gingivalis, T. denticola, and T. forsythia over the calvaria, after which the soft tissues and calvarial bones were excised. A Murine GeneChip® array analysis of transcript profiles showed that 6997 genes were differentially expressed in calvarial bones (P < 0.05) and 1544 genes were differentially transcribed in the inflamed tissues after the polymicrobial infection. Of these genes, 4476 and 1035 genes in the infected bone and tissues were differentially expressed by upregulation. Biological pathways significantly impacted by the polymicrobial infection in calvarial bone included leukocyte transendothelial migration (LTM), cell adhesion molecules, adherens junction, major histocompatibility complex antigen, extracellular matrix-receptor interaction (ECM), and antigen processing and presentation resulting in inflammatory/cytokine/chemokine transcripts stimulation in bone and soft tissue. Intense inflammation and increased activated osteoclasts was observed in calvarias compared to sham-infected controls. Quantitative real-time RT-PCR analysis confirmed mRNA level of selected genes corresponded with the microarray expression. The polymicrobial infection regulated several LTM and extracellular membrane (ECM) pathway genes in a manner distinct from monoinfection with P. gingivalis, T. denticola, or T. forsythia. To our knowledge, this is the first definition of the polymicrobial induced transcriptome in calvarial bone and soft tissue in response to periodontal pathogens. PMID:21896157

Photothermal stress triggered by near infrared-irradiated carbon nanotubes promotes bone deposition in rat calvarial defects.

PubMed

Yanagi, Tsukasa; Kajiya, Hiroshi; Kawaguchi, Minoru; Kido, Hirofumi; Fukushima, Tadao

2015-03-01

The bone regenerative healing process is often prolonged, with a high risk of infection particularly in elderly and diseased patients. A reduction in healing process time usually requires mechanical stress devices, chemical cues, or laser/thermal therapies. Although these approaches have been used extensively for the reduction of bone healing time, the exact mechanisms involved in thermal stress-induced bone regeneration remain unclear. In this study, we investigated the effect of optimal hyperthermia on rat calvarial defects in vivo and on osteogenesis in vitro. Photothermal stress stimulation was carried out using a new photothermal device, composed of an alginate gel including in carbon nanotubes and their irradiator with near-infrared light. Photothermal stress (15 min at 42℃, every day), trigged by near-infrared-induced carbon nanotube, promoted bone deposition in critical-sized calvarial defects compared with nonthermal stress controls. We recently reported that our novel DNA/protamine complex scaffold induces bone regeneration in calvarial defects. In this study, photothermal stress upregulated bone deposition in DNA/protamine-engrafted calvarial defects. Furthermore, photothermal stress significantly induced expression of osteogenic related genes in a time-dependent manner, including alkaline phosphatase, osterix, and osteocalcin. This was observed in DNA/protamine cells, which were expanded from regenerated tissue engrafted into the DNA/protamine scaffold, as well as in human MG63 preosteoblasts. In summary, this novel carbon nanotube-based photothermal stress approach upregulated expression of osteogenic-related genes in preosteoblasts, resulting in promotion of mineral deposition for enhanced bone repair. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

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.

Effect of epimedium pubescen flavonoid on bone mineral status and bone turnover in male rats chronically exposed to cigarette smoke

PubMed Central

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

Effect of epimedium pubescen flavonoid on bone mineral status and bone turnover in male rats chronically exposed to cigarette smoke.

PubMed

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.

Artifacts produced during electrical stimulation of the vestibular nerve in cats. [autonomic nervous system components of motion sickness

NASA Technical Reports Server (NTRS)

Tang, P. C.

1973-01-01

Evidence is presented to indicate that evoked potentials in the recurrent laryngeal, the cervical sympathetic, and the phrenic nerve, commonly reported as being elicited by vestibular nerve stimulation, may be due to stimulation of structures other than the vestibular nerve. Experiments carried out in decerebrated cats indicated that stimulation of the petrous bone and not that of the vestibular nerve is responsible for the genesis of evoked potentials in the recurrent laryngeal and the cervical sympathetic nerves. The phrenic response to electrical stimulation applied through bipolar straight electrodes appears to be the result of stimulation of the facial nerve in the facial canal by current spread along the petrous bone, since stimulation of the suspended facial nerve evoked potentials only in the phrenic nerve and not in the recurrent laryngeal nerve. These findings indicate that autonomic components of motion sickness represent the secondary reactions and not the primary responses to vestibular stimulation.

Electromagnetic pulses bone healing booster

NASA Astrophysics Data System (ADS)

Sintea, S. R.; Pomazan, V. M.; Bica, D.; Grebenisan, D.; Bordea, N.

2015-11-01

Posttraumatic bone restoration triggered by the need to assist and stimulate compensatory bone growth in periodontal condition. Recent studies state that specific electromagnetic stimulation can boost the bone restoration, reaching up to 30% decrease in recovery time. Based on the existing data on the electromagnetic parameters, a digital electronic device is proposed for intra oral mounting and bone restoration stimulation in periodontal condition. The electrical signal is applied to an inductive mark that will create and impregnate magnetic field in diseased tissue. The device also monitors the status of the electromagnetic field. Controlled wave forms and pulse frequency signal at programmable intervals are obtained with optimized number of components and miniaturized using surface mounting devices (SMD) circuits and surface mounting technology (SMT), with enhanced protection against abnormal current growth, given the intra-oral environment. The system is powered by an autonomous power supply (battery), to limit the problems caused by powering medical equipment from the main power supply. Currently the device is used in clinical testing, in cycles of six up to twelve months. Basic principles for the electrical scheme and algorithms for pulse generation, pulse control, electromagnetic field control and automation of current monitoring are presented, together with the friendly user interface, suitable for medical data and patient monitoring.

Sphingosine 1-Phosphate (S1P) Receptors 1 and 2 Coordinately Induce Mesenchymal Cell Migration through S1P Activation of Complementary Kinase Pathways*

PubMed Central

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

Dura Mater Stimulates Human Adipose-Derived Stromal Cells to Undergo Bone Formation in Mouse Calvarial Defects

PubMed Central

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

The effects of low-intensity pulsed ultrasound and pulsed electromagnetic fields bone growth stimulation in acute fractures: a systematic review and meta-analysis of randomized controlled trials.

PubMed

Hannemann, P F W; Mommers, E H H; Schots, J P M; Brink, P R G; Poeze, M

2014-08-01

The aim of this systematic review and meta-analysis was to evaluate the best currently available evidence from randomized controlled trials comparing pulsed electromagnetic fields (PEMF) or low-intensity pulsed ultrasound (LIPUS) bone growth stimulation with placebo for acute fractures. We performed a systematic literature search of the medical literature from 1980 to 2013 for randomized clinical trials concerning acute fractures in adults treated with PEMF or LIPUS. Two reviewers independently determined the strength of the included studies by assessing the risk of bias according to the criteria in the Cochrane Handbook for Systematic Reviews of Interventions. Seven hundred and thirty-seven patients from 13 trials were included. Pooled results from 13 trials reporting proportion of nonunion showed no significant difference between PEMF or LIPUS and control. With regard to time to radiological union, we found heterogeneous results that significantly favoured PEMF or LIPUS bone growth stimulation only in non-operatively treated fractures or fractures of the upper limb. Furthermore, we found significant results that suggest that the use of PEMF or LIPUS in acute diaphyseal fractures may accelerate the time to clinical union. Current evidence from randomized trials is insufficient to conclude a benefit of PEMF or LIPUS bone growth stimulation in reducing the incidence of nonunions when used for treatment in acute fractures. However, our systematic review and meta-analysis suggest that PEMF or LIPUS can be beneficial in the treatment of acute fractures regarding time to radiological and clinical union. PEMF and LIPUS significantly shorten time to radiological union for acute fractures undergoing non-operative treatment and acute fractures of the upper limb. Furthermore, PEMF or LIPUS bone growth stimulation accelerates the time to clinical union for acute diaphyseal fractures.

Oxytocin and bone

PubMed Central

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

BONE MARROW–DERIVED DENDRITIC CELL PROGENITORS (NLDC 145+, MHC CLASS II+, B7–1dim, B7–2−) INDUCE ALLOANTIGEN-SPECIFIC HYPORESPONSIVENESS IN MURINE T LYMPHOCYTES12

PubMed Central

Lu, Lina; McCaslin, Delbert; Starzl, Thomas E.; Thomson, Angus W.

2010-01-01

The functional maturation of dendritic cells (DC) and other antigen-presenting cells is believed to reflect the upregulation of cell surface major histocompatibility complex (MHC) class II and other T cell co-stimulatory molecules, especially the CD28 ligands B7–1 (CD80) and B7–2 (CD86). In this study, we propagated cells exhibiting characteristics of DC precursors from the bone marrow (BM) of BIO mice (H-2b; I-A1) in response to granulocyte-macrophage colony stimulating factor (GM-CSF). The methods used were similar to those employed previously to propagate DC progenitors from normal mouse liver. Cells expressing DC lineage markers (NLDC 145+, 33D1+ N418+) harvested from 8–10-day GM-CSF stimulated BM cell cultures were CD45+, heat-stable antigen+, CD54+, CD44+, MHC class II+, B7–1dim but B7–2− (costimulatory molecule-deficient). Supplementation of cultures with interleukin-4 (IL-4) in addition to GM-CSF however, resulted in marked upregulation of MHC class II and B7–2 expression. These latter cells exhibited potent allostimulatory activity in primary mixed leukocyte cultures. In contrast, the cells stimulated with GM-CSF alone were relatively weak stimulators and induced alloantigen-specific hyporesponsiveness in allogeneic T cells (C3H; H-2k; I-E+) detected upon re-stimulation in secondary MLR. This was associated with blockade of IL-2 production. Reactivity to third-party stimulators was intact. The hyporesponsiveness induced by the GM-CSF stimulated, costimulatory molecule-deficient cells was prevented by incorporation of anti-CD28 monoclonal antibody in the primary MLR and was reversed by addition of IL-2 to restimulated T cells. The findings show that MHC class II+ B7–2− cells with a DC precursor phenotype can induce alloantigen-specific hyporesponsiveness in vitro. Under the appropriate conditions, such costimulatory molecule-deficient cells could contribute to the induction of donor-specific unresponsiveness in vivo. PMID:8545887

Novel, non-steroidal, selective androgen receptor modulators (SARMs) with anabolic activity in bone and muscle and improved safety profile.

PubMed

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.

WAIF1 Is a Cell-Surface CTHRC1 Binding Protein Coupling Bone Resorption and Formation.

PubMed

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.

Bone Regeneration Based on Tissue Engineering Conceptions — A 21st Century Perspective

PubMed Central

Henkel, Jan; Woodruff, Maria A.; Epari, Devakara R.; Steck, Roland; Glatt, Vaida; Dickinson, Ian C.; Choong, Peter F. M.; Schuetz, Michael A.; Hutmacher, Dietmar W.

2013-01-01

The role of Bone Tissue Engineering in the field of Regenerative Medicine has been the topic of substantial research over the past two decades. Technological advances have improved orthopaedic implants and surgical techniques for bone reconstruction. However, improvements in surgical techniques to reconstruct bone have been limited by the paucity of autologous materials available and donor site morbidity. Recent advances in the development of biomaterials have provided attractive alternatives to bone grafting expanding the surgical options for restoring the form and function of injured bone. Specifically, novel bioactive (second generation) biomaterials have been developed that are characterised by controlled action and reaction to the host tissue environment, whilst exhibiting controlled chemical breakdown and resorption with an ultimate replacement by regenerating tissue. Future generations of biomaterials (third generation) are designed to be not only osteoconductive but also osteoinductive, i.e. to stimulate regeneration of host tissues by combining tissue engineering and in situ tissue regeneration methods with a focus on novel applications. These techniques will lead to novel possibilities for tissue regeneration and repair. At present, tissue engineered constructs that may find future use as bone grafts for complex skeletal defects, whether from post-traumatic, degenerative, neoplastic or congenital/developmental “origin” require osseous reconstruction to ensure structural and functional integrity. Engineering functional bone using combinations of cells, scaffolds and bioactive factors is a promising strategy and a particular feature for future development in the area of hybrid materials which are able to exhibit suitable biomimetic and mechanical properties. This review will discuss the state of the art in this field and what we can expect from future generations of bone regeneration concepts. PMID:26273505

Pregnancy-associated plasma protein-A modulates the anabolic effects of parathyroid hormone in mouse bone.

PubMed

Clifton, Kari B; Conover, Cheryl A

2015-12-01

Intermittent parathyroid hormone (PTH) is a potent anabolic therapy for bone, and several studies have implicated local insulin-like growth factor (IGF) signaling in mediating this effect. The IGF system is complex and includes ligands and receptors, as well as IGF binding proteins (IGFBPs) and IGFBP proteases. Pregnancy-associated plasma protein-A (PAPP-A) is a metalloprotease expressed by osteoblasts in vitro that has been shown to enhance local IGF action through cleavage of inhibitory IGFBP-4. This study was set up to test two specific hypotheses: 1) Intermittent PTH treatment increases the expression of IGF-I, IGFBP-4 and PAPP-A in bone in vivo, thereby increasing local IGF activity. 2) In the absence of PAPP-A, local IGF activity and the anabolic effects of PTH on bone are reduced. Wild-type (WT) and PAPP-A knock-out (KO) mice were treated with 80 μg/kg human PTH 1-34 or vehicle by subcutaneous injection five days per week for six weeks. IGF-I, IGFBP-4 and PAPP-A mRNA expression in bone were significantly increased in response to PTH treatment. PTH treatment of WT mice, but not PAPP-A KO mice, significantly increased expression of an IGF-responsive gene. Bone mineral density (BMD), as measured by DEXA, was significantly decreased in femurs of PAPP-A KO compared to WT mice with PTH treatment. Volumetric BMD, as measured by pQCT, was significantly decreased in femoral midshaft (primarily cortical bone), but not metaphysis (primarily trabecular bone), of PAPP-A KO compared to WT mice with PTH treatment. These data suggest that stimulation of PAPP-A expression by intermittent PTH treatment contributes to PTH bone anabolism in mice. Copyright © 2015 Elsevier Inc. All rights reserved.

IGF-1 signaling mediated cell-specific skeletal mechano-transduction.

PubMed

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.

Central and peripheral mechanisms of the NPY system in the regulation of bone and adipose tissue.

PubMed

Shi, Yan-Chuan; Baldock, Paul A

2012-02-01

Skeletal research is currently undergoing a period of marked expansion. The boundaries of "bone" research are being re-evaluated and with this, a growing recognition of a more complex and interconnected biology than previously considered. One aspect that has become the focus of particular attention is the relationship between bone and fat homeostasis. Evidence from a number of avenues indicates that bone and adipose regulation are both related and interdependent. This review examines the neuropeptide Y (NPY) system, known to exert powerful control over both bone and fat tissue. The actions of this system are characterized by signaling both within specific nuclei of the hypothalamus and also the target tissues, mediated predominantly through two G-protein coupled receptors (Y1 and Y2). In bone tissue, elevated NPY levels act consistently to repress osteoblast activity. Moreover, both central Y2 receptor and osteoblastic Y1 receptor signaling act similarly to repress bone formation. Conversely, loss of NPY expression or receptor signaling induces increased osteoblast activity and bone mass in both cortical and cancellous envelopes. In fat tissue, NPY action is more complex. Energy homeostasis is powerfully altered by elevations in hypothalamic NPY, resulting in increases in fat accretion and body-wide energy conservation, through the action of locally expressed Y1 receptors, while local Y2 receptors act to inhibit NPY-ergic tone. Loss of central NPY expression has a markedly reduced effect, consistent with a physiological drive to promote fat accretion. In fat tissue, NPY and Y1 receptors act to promote lipogenesis, consistent with their roles in the brain. Y2 receptors expressed in adipocytes also act in this manner, showing an opposing action to their role in the hypothalamus. While direct investigation of these processes has yet to be completed, these responses appear to be interrelated to some degree. The starvation-based signal of elevated central NPY inducing marked inhibition of osteoblast activity, whilst promoting fat accretion, indicating skeletal tissue is a component of the energy conservation system. Moreover, when NPY expression is reduced, consistent with high calorie intake and weight gain, bone formation is stimulated, strengthening the skeleton. In conclusion, NPY acts to regulate both bone and fat tissue in a coordinated manner, and remains a strong candidate for mediating interactions between these two tissues. Copyright © 2011 Elsevier Inc. All rights reserved.

Differential growth factor control of bone formation through osteoprogenitor differentiation.

PubMed

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.

Cyclic hydrostatic pressure stimulates enhanced bone development in the foetal chick femur in vitro.

PubMed

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.

Traf2 interacts with Smad4 and regulates BMP signaling pathway in MC3T3-E1 osteoblasts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shimada, Koichi, E-mail: shimada-ki@dent.nihon-u.ac.jp; Division of Advanced Dental Treatment, Dental Research Center, Nihon University School of Dentistry, Tokyo; Ikeda, Kyoko

2009-12-18

Bone morphogenetic proteins (BMPs) play important roles in osteoblast differentiation and maturation. In mammals, the BMP-induced receptor-regulated Smads form complexes with Smad4. These complexes translocate and accumulate in the nucleus, where they regulate the transcription of various target genes. However, the function of Smad4 remains unclear. We performed a yeast two-hybrid screen using Smad4 as bait and a cDNA library derived from bone marrow, to indentify the proteins interacting with Smad4. cDNA clones for Tumor necrosis factor (TNF) receptor-associated factor 2 (Traf2) were identified, and the interaction between the endogenous proteins was confirmed in the mouse osteoblast cell line MC3T3-E1.more » To investigate the function of Traf2, we silenced it with siRNA. The level of BMP-2 protein in the medium, the expression levels of the Bmp2 gene and BMP-induced transcription factor genes, including Runx2, Dlx5, Msx2, and Sp7, and the phosphorylated-Smad1 protein level were increased in cells transfected with Traf2 siRNA. The nuclear accumulation of Smad1 increased with TNF-{alpha} stimulation for 30 min at Traf2 silencing. These results suggest that the TNF-{alpha}-stimulated nuclear accumulation of Smad1 may be dependent on Traf2. Thus, the interaction between Traf2 and Smad4 may play a role in the cross-talk between TNF-{alpha} and BMP signaling pathways.« less

Rictor/mammalian target of rapamycin complex 2 promotes macrophage activation and kidney fibrosis.

PubMed

Ren, Jiafa; Li, Jianzhong; Feng, Ye; Shu, Bingyan; Gui, Yuan; Wei, Wei; He, Weichun; Yang, Junwei; Dai, Chunsun

2017-08-01

Mammalian target of rapamycin (mTOR) signalling controls many essential cellular functions. However, the role of Rictor/mTOR complex 2 (mTORC2) in regulating macrophage activation and kidney fibrosis remains largely unknown. We report here that Rictor/mTORC2 was activated in macrophages from the fibrotic kidneys of mice. Ablation of Rictor in macrophages reduced kidney fibrosis, inflammatory cell accumulation, macrophage proliferation and polarization after unilateral ureter obstruction or ischaemia/reperfusion injury. In bone marrow-derived macrophages (BMMs), deletion of Rictor or blockade of protein kinase Cα inhibited cell migration. Additionally, deletion of Rictor or blockade of Akt abolished interleukin-4-stimulated or transforming growth factor (TGF)-β1-stimulated macrophage M2 polarization. Furthermore, deletion of Rictor downregulated TGF-β1-stimulated upregulation of multiple profibrotic cytokines, including platelet-derived growth factor, vascular endothelial growth factor and connective tissue growth factor, in BMMs. Conditioned medium from TGF-β1-pretreated Rictor -/- macrophages stimulated fibroblast activation less efficiently than that from TGF-β1-pretreated Rictor +/+ macrophages. These results demonstrate that Rictor/mTORC2 signalling can promote macrophage activation and kidney fibrosis. Targeting this signalling pathway in macrophages may shine light on ways to protect against kidney fibrosis in patients with chronic kidney diseases. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

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.

Bone stimulation for fracture healing: What's all the fuss?

PubMed Central

Victoria, Galkowski; Petrisor, Brad; Drew, Brian; Dick, David

2009-01-01

Approximately 10% of the 7.9 million annual fracture patients in the United States experience nonunion and/or delayed unions, which have a substantial economic and quality of life impact. A variety of devices are being marketed under the name of “bone growth stimulators.” This article provides an overview of electrical and electromagnetic stimulation, ultrasound, and extracorporeal shock waves. More research is needed for knowledge of appropriate device configurations, advancement in the field, and encouragement in the initiation of new trials, particularly large multicenter trials and randomized control trials that have standardized device and protocol methods. PMID:19838359

The botanical molecule p-hydroxycinnamic acid as a new osteogenic agent: insight into the treatment of cancer bone metastases.

PubMed

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.

Rap system of stress stimulation can promote bone union after lower tibial bone fracture: a clinical research.

PubMed

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.

Enhanced osteoporotic bone regeneration by strontium-substituted calcium silicate bioactive ceramics.

PubMed

Lin, Kaili; Xia, Lunguo; Li, Haiyan; Jiang, Xinquan; Pan, Haobo; Xu, Yuanjin; Lu, William W; Zhang, Zhiyuan; Chang, Jiang

2013-12-01

The regeneration capacity of the osteoporotic bones is generally lower than that of the normal bones. Current methods of bone defect treatment for osteoporosis are not always satisfactory. Recent studies have shown that the silicate based biomaterials can stimulate osteogenesis and angiogenesis due to the silicon (Si) ions released from the materials, and enhance bone regeneration in vivo. Other studies showed that strontium (Sr) plays a distinct role on inhibiting bone resorption. Based on the hypothesis that the combination of Si and Sr may have synergetic effects on osteoporotic bone regeneration, the porous Sr-substituted calcium silicate (SrCS) ceramic scaffolds combining the functions of Sr and Si elements were developed with the goals to promote osteoporotic bone defect repair. The effects of the ionic extract from SrCS on osteogenic differentiation of bone marrow mesenchymal stem cells derived from ovariectomized rats (rBMSCs-OVX), angiogenic differentiation of human umbilical vein endothelial cells (HUVECs) were investigated. The in vitro results showed that Sr and Si ions released from SrCS enhanced cell viability, alkaline phosphatase (ALP) activity, and mRNA expression levels of osteoblast-related genes of rBMSCs-OVX and expression of vascular endothelial growth factor (VEGF) without addition of extra osteogenic and angiogenic reagents. The activation in extracellular signal-related kinases (ERK) and p38 signaling pathways were observed in rBMSCs-OVX cultured in the extract of SrCS, and these effects could be blocked by ERK inhibitor PD98059, and P38 inhibitor SB203580, respectively. Furthermore, the ionic extract of SrCS stimulated HUVECs proliferation, differentiation and angiogenesis process. The in vivo experiments revealed that SrCS dramatically stimulated bone regeneration and angiogenesis in a critical sized OVX calvarial defect model, and the enhanced bone regeneration might be attributed to the modulation of osteogenic differentiation of endogenous mesenchymal stem cells (MSCs) and the inhibition of osteoclastogenesis, accompanying with the promotion of the angiogenic activity of endothelial cells (ECs). Copyright © 2013 Elsevier Ltd. All rights reserved.

Small subchondral drill holes improve marrow stimulation of articular cartilage defects.

PubMed

Eldracher, Mona; Orth, Patrick; Cucchiarini, Magali; Pape, Dietrich; Madry, Henning

2014-11-01

Subchondral drilling is an established marrow stimulation technique. Osteochondral repair is improved when the subchondral bone is perforated with small drill holes, reflecting the physiological subchondral trabecular distance. Controlled laboratory study. A rectangular full-thickness chondral defect was created in the trochlea of adult sheep (n = 13) and treated with 6 subchondral drillings of either 1.0 mm (reflective of the trabecular distance) or 1.8 mm in diameter. Osteochondral repair was assessed after 6 months in vivo by macroscopic, histological, and immunohistochemical analyses and by micro-computed tomography. The application of 1.0-mm subchondral drill holes led to significantly improved histological matrix staining, cellular morphological characteristics, subchondral bone reconstitution, and average total histological score as well as significantly higher immunoreactivity to type II collagen and reduced immunoreactivity to type I collagen in the repair tissue compared with 1.8-mm drill holes. Analysis of osteoarthritic changes in the cartilage adjacent to the defects revealed no significant differences between treatment groups. Restoration of the microstructure of the subchondral bone plate below the chondral defects was significantly improved after 1.0-mm compared to 1.8-mm drilling, as shown by higher bone volume and reduced thickening of the subchondral bone plate. Likewise, the microarchitecture of the drilled subarticular spongiosa was better restored after 1.0-mm drilling, indicated by significantly higher bone volume and more and thinner trabeculae. Moreover, the bone mineral density of the subchondral bone in 1.0-mm drill holes was similar to the adjacent subchondral bone, whereas it was significantly reduced in 1.8-mm drill holes. No significant correlations existed between cartilage and subchondral bone repair. Small subchondral drill holes that reflect the physiological trabecular distance improve osteochondral repair in a translational model more effectively than larger drill holes. These results have important implications for the use of subchondral drilling for marrow stimulation, as they support the use of small-diameter bone-cutting devices. © 2014 The Author(s).

Role of nutritional zinc in the prevention of osteoporosis.

PubMed

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.

Salubrinal improves mechanical properties of the femur in osteogenesis imperfecta mice.

PubMed

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.

Arctigenin suppresses receptor activator of nuclear factor κB ligand (RANKL)-mediated osteoclast differentiation in bone marrow-derived macrophages.

PubMed

Kim, A-Ram; Kim, Hyuk Soon; Lee, Jeong Min; Choi, Jung Ho; Kim, Se Na; Kim, Do Kyun; Kim, Ji Hyung; Mun, Se Hwan; Kim, Jie Wan; Jeon, Hyun Soo; Kim, Young Mi; Choi, Wahn Soo

2012-05-05

Osteoclasts, multinucleated bone-resorbing cells, are closely associated with bone diseases such as rheumatoid arthritis and osteoporosis. Osteoclasts are derived from hematopoietic precursor cells, and their differentiation is mediated by two cytokines, including macrophage colony stimulating factor and receptor activator of nuclear factor κB ligand (RANKL). Previous studies have shown that arctigenin exhibits an anti-inflammatory effect. However, the effect of arctigenin on osteoclast differentiation is yet to be elucidated. In this study, we found that arctigenin inhibited RANKL-mediated osteoclast differentiation in bone marrow macrophages in a dose-dependent manner and suppressed RANKL-mediated bone resorption. Additionally, the expression of typical marker proteins, such as NFATc1, c-Fos, TRAF6, c-Src, and cathepsin K, were significantly inhibited. Arctigenin inhibited the phosphorylation of Erk1/2, but not p38 and JNK, in a dose-dependent manner. Arctigenin also dramatically suppressed immunoreceptor tyrosine-based activation motif-mediated costimulatory signaling molecules, including Syk and PLCγ2, and Gab2. Notably, arctigenin inhibited the activation of Syk through RANKL stimulation. Furthermore, arctigenin prevented osteoclast differentiation in the calvarial bone of mice following stimulation with lipopolysaccharide. Our results show that arctigenin inhibits osteoclast differentiation in vitro and in vivo. Therefore, arctigenin may be useful for treating rheumatoid arthritis and osteoporosis. Copyright © 2012 Elsevier B.V. All rights reserved.

Skeletal muscle contractions uncoupled from gravitational loading directly increase cortical bone blood flow rates in vivo.

PubMed

Caulkins, Carrie; Ebramzadeh, Edward; Winet, Howard

2009-05-01

The direct and indirect effects of muscle contraction on bone microcirculation and fluid flow are neither well documented nor explained. However, skeletal muscle contractions may affect the acquisition and maintenance of bone via stimulation of bone circulatory and interstitial fluid flow parameters. The purposes of this study were to assess the effects of transcutaneous electrical neuromuscular stimulation (TENS)-induced muscle contractions on cortical bone blood flow and bone mineral content, and to demonstrate that alterations in blood flow could occur independently of mechanical loading and systemic circulatory mechanisms. Bone chamber implants were used in a rabbit model to observe real-time blood flow rates and TENS-induced muscle contractions. Video recording of fluorescent microspheres injected into the blood circulation was used to calculate changes in cortical blood flow rates. TENS-induced repetitive muscle contractions uncoupled from mechanical loading instantaneously increased cortical microcirculatory flow, directly increased bone blood flow rates by 130%, and significantly increased bone mineral content over 7 weeks. Heart rates and blood pressure did not significantly increase due to TENS treatment. Our findings suggest that muscle contraction therapies have potential clinical applications for improving blood flow to cortical bone in the appendicular skeleton. Copyright 2008 Orthopaedic Research Society

Conjugated linoleic acid prevents age-induced bone loss in mice by regulating both osteoblastogenesis and adipogenesis.

PubMed

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.

Transient Overexpression of Sonic Hedgehog Alters the Architecture and Mechanical Properties of Trabecular Bone

PubMed Central

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

Mechanical Stimulation and IGF-1 Enhance mRNA Translation Rate in Osteoblasts Via Activation of the AKT-mTOR Pathway.

PubMed

Bakker, Astrid D; Gakes, Tom; Hogervorst, Jolanda M A; de Wit, Gerard M J; Klein-Nulend, Jenneke; Jaspers, Richard T

2016-06-01

Insulin-like growth factor-1 (IGF-1) is anabolic for muscle by enhancing the rate of mRNA translation via activation of AKT and subsequent activation of the mammalian target of rapamycin complex 1 (mTOR), thereby increasing cellular protein production. IGF-1 is also anabolic for bone, but whether the mTOR pathway plays a role in the rate of bone matrix protein production by osteoblasts is unknown. We hypothesized that anabolic stimuli such as mechanical loading and IGF-1 stimulate protein synthesis in osteoblasts via activation of the AKT-mTOR pathway. MC3T3-E1 osteoblasts were either or not subjected for 1 h to mechanical loading by pulsating fluid flow (PFF) or treated with or without human recombinant IGF-1 (1-100 ng/ml) for 0.5-6 h, to determine phosphorylation of AKT and p70S6K (downstream of mTOR) by Western blot. After 4 days of culture with or without the mTOR inhibitor rapamycin, total protein, DNA, and gene expression were quantified. IGF-1 (100 ng/ml) reduced IGF-1 gene expression, although PFF enhanced IGF-1 expression. IGF-1 did not affect collagen-I gene expression. IGF-1 dose-dependently enhanced AKT and p70S6K phosphorylation at 2 and 6 h. PFF enhanced phosphorylation of AKT and p70S6K already within 1 h. Both IGF-1 and PFF enhanced total protein per cell by ∼30%, but not in the presence of rapamycin. Our results show that IGF-1 and PFF activate mTOR, thereby stimulating the rate of mRNA translation in osteoblasts. The known anabolic effect of mechanical loading and IGF-1 on bone may thus be partly explained by mTOR-mediated enhanced protein synthesis in osteoblasts. © 2015 Wiley Periodicals, Inc.

A soluble bone morphogenetic protein type IA receptor increases bone mass and bone strength

PubMed Central

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

The role of lipopolysaccharide in infectious bone resorption of periapical lesion.

PubMed

Hong, Chi-Yuan; Lin, Sze-Kwan; Kok, Sang-Heng; Cheng, Shih-Jung; Lee, Ming-Shu; Wang, Tong-Mei; Chen, Chuan-Shuo; Lin, Li-Deh; Wang, Juo-Song

2004-03-01

The role of lipopolysaccharide (LPS) in periapical lesion-induced bone resorption was investigated. Polymyxin B (PMB), a specific inhibitor of LPS, was evaluated to treat the apical lesion. Lipopolysaccharide isolated from two common endodontic pathogens, Fusobacterium nucleatum and Porphyromonas endodontalis, stimulated mouse macrophage (J774) to release interleukin-1alpha (IL-1 alpha) and tumor necrosis factor-alpha (TNF-alpha) in a time-dependent manner. Combination of LPS further enhanced the stimulation. PMB inhibited these effects significantly. LPS also stimulated matrix metalloproteinase-1 (MMP-1) gene expression in J774, whereas anti-IL-1 alpha and anti-TNF-alpha antibodies, as well as PMB, diminished this effect. A disease model of periapical lesion was established in Wistar rat. Administration of PMB reduced the extent of lesion-associated bone resorption by 76% to approximately 80%, and simultaneously reduced the numbers of MMP-1-producing macrophages. It is suggested that LPS released from the infected root canal triggers the synthesis of IL-1 alpha and TNF-alpha from macrophages. These pro-inflammatory cytokines up-regulate the production of MMP-1 by macrophages to promote periapical bone resorption.

Effect of electrical stimulation and hot boning on the eating quality of Gannan yak longissimus lumborum.

PubMed

Lang, Yumiao; Sha, Kun; Zhang, Rui; Xie, Peng; Luo, Xin; Sun, Baozhong; Li, Haipeng; Zhang, Li; Zhang, Songshan; Liu, Xuan

2016-02-01

The objective of this study was to evaluate the effects of electrical stimulation (ES) versus non-electrical stimulation (NES) and type of boning (hot versus cold) on the eating quality of Gannan yak longissimus lumborum. Eighteen Gannan yak bulls were randomly divided into two groups: ES and NES. Hot boning (HB) and cold boning (CB) were applied to the left and right side of the carcasses, respectively. All of the four treatments missed the "ideal" pH/temperature window. HB reduced the rate of pH decline, decreased meat tenderness and water holding capacity. ES increased the rate of pH decline and improved yak meat tenderness (P<0.05); however, ES explained only 1% of the variation in WBSF. HB and ES had no significant effects on cooking loss, L* or b* values of yak meat. Postmortem aging increased yak meat tenderness and improved meat color parameters. HB had negative effects on yak meat quality, while ES could not reverse these deleterious effects. Copyright © 2015 Elsevier Ltd. All rights reserved.

Biomechanical and biophysical environment of bone from the macroscopic to the pericellular and molecular level.

PubMed

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.

Novel Development of Phosphate Treated Porous Hydroxyapatite.

PubMed

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.

Novel Development of Phosphate Treated Porous Hydroxyapatite

PubMed Central

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

Enhanced Soft Tissue Attachment and Fixation Using a Mechanically-Stimulated Cytoselective Tissue-Specific ECM Coating

DTIC Science & Technology

2012-08-01

currently used for surgical reinforcement for tendon rotator cuff repair . All scaffolds in this study were seeded using this protocol. PLA fabric...extracellular matrix scaffolds for rotator cuff tendon repair . Biomechanical, biochemical, and cellular properties. J Bone Joint Surg Am 2006;88(12):2665-72...mechanical stimulation of a co-cultured biomaterial scaffold can improve/expedite healing of a tendon-to-bone interface for soft tissue repair . There

Testosterone Combined with Electrical Stimulation and Standing: Effect on Muscle and Bone

DTIC Science & Technology

2015-10-01

JJPVAMC). During year 1 of the study, the Study Team (Drs. Forrest, Bauman, and Harkema) established a new partnership with a pharmaceutical company...AbbVie) to supply Drug and Placebo for all potential study participants. Each of the study sites submitted to the pharmaceutical company all requested...stimulation, dynamic standing protocol, muscle volume, MRI , bone mineral density, DXA, QCT scans, blood markers, urine markers, 60 sessions of training

Effects of short-term hypothermal and contrast exposure on immunophysiological parameters of laboratory animals.

PubMed

Kalenova, L F; Fisher, T A; Suhovey, J G; Besedin, I M

2009-05-01

Experiments on inbred animals showed that short-term exposure in cold water significantly modified structural and functional parameters of the immune system at different levels of its organization, from bone marrow hemopoiesis to effector stage of the immune response to antigen. The thermal factor caused changes in nonspecific and specific mechanisms of the immune system. Hypothermal exposure (7-9 degrees C, 5 sec) increased the thymic index and bone marrow lymphocyte count, reduced absorption capacity and stimulated metabolic activity of phagocytes, stimulated cell-mediated and suppressed humoral immunity. Contrast exposure in cold and hot water (7-9 degrees C, 5 sec/40-42 degrees C, 30 sec) increased monocyte count in bone marrow and reduced it in the their peripheral blood, reduced metabolic activity of phagocytes, stimulated cell-mediated and suppressed humoral immunity. These data demonstrate physiological mechanisms of interactions between the thermoregulatory and immune systems.

Stimulation of Mucosal Mast Cell Growth in Normal and Nude Rat Bone Marrow Cultures

NASA Astrophysics Data System (ADS)

Haig, David M.; McMenamin, Christine; Gunneberg, Christian; Woodbury, Richard; Jarrett, Ellen E. E.

1983-07-01

Mast cells with the morphological and biochemical properties of mucosal mast cells (MMC) appear and proliferate to form the predominant cell type in rat bone marrow cultures stimulated with factors from antigen- or mitogen-activated lymphocytes. Conditioned media causing a selective proliferation of MMC were derived from mesenteric lymph node cells of Nippostrongylus brasiliensis-infected rats restimulated in vitro with specific antigen or from normal or infected rat mesenteric lymph node cells stimulated with concanavalin A. MMC growth factor is not produced by T-cell-depleted mesenteric lymph node cells or by the mesenteric lymph node cells of athymic rats. By contrast, MMC precursors are present in the bone marrow of athymic rats and are normally receptive to the growth factor produced by the lymphocytes of thymus-intact rats. The thymus dependence of MMC hyperplasia is thus based on the requirement of a thymus-independent precursor for a T-cell-derived growth promoter.

Infected nonunion of tibia

PubMed Central

Chaudhary, Milind Madhav

2017-01-01

Infected nonunions of tibia pose many challenges to the treating surgeon and the patient. Challenges include recalcitrant infection, complex deformities, sclerotic bone ends, large bone gaps, shortening, and joint stiffness. They are easy to diagnose and difficult to treat. The ASAMI classification helps decide treatment. The nonunion severity score proposed by Calori measures many parameters to give a prognosis. The infection severity score uses simple clinical signs to grade severity of infection. This determines number of surgeries and allows choice of hardware, either external or internal for definitive treatment. Co-morbid factors such as smoking, diabetes, nonsteroidal anti-inflammatory drug use, and hypovitaminosis D influence the choice and duration of treatment. Thorough debridement is the mainstay of treatment. Removal of all necrotic bone and soft tissue is needed. Care is exercised in shaping bone ends. Internal fixation can help achieve union if infection was mild. Severe infections need external fixation use in a second stage. Compression at nonunion site achieves union. It can be combined with a corticotomy lengthening at a distant site for equalization. Soft tissue deficit has to be covered by flaps, either local or microvascular. Bone gaps are best filled with the reliable technique of bone transport. Regenerate bone may be formed proximally, distally, or at both sites. Acute compression can fill bone gaps and may need a fibular resection. Gradual reduction of bone gap happens with bone transport, without need for fibulectomy. When bone ends dock, union may be achieved by vertical or horizontal compression. Biological stimulus from iliac crest bone grafts, bone marrow aspirate injections, and platelet concentrates hasten union. Bone graft substitutes add volume to graft and help fill defects. Addition of rh-BMP-7 may help in healing albeit at a much higher cost. Regeneration may need stimulation and augmentation. Induced membrane technique is an alternative to bone transport to fill gaps. It needs large amounts of bone graft from iliac crest or femoral canal. This is an expensive method physiologically and economically. Infection can resorb the graft and cause failure of treatment. It can be done in select cases after thorough eradication of infection. Patience and perseverance are needed for successful resolution of infection and achieving union. PMID:28566776

DNA in a Tunnel: A Comfy Spot for Recognition - or -The Structure of BsoBI Complexed with DNA. What can we Learn about Function via Structure Determination and how can this be Applied to Bone or Muscle Biology?

NASA Technical Reports Server (NTRS)

vanderWoerd, Mark

2004-01-01

The structure and function of a biologically active molecule are related. To understand its function, it is necessary (but not always sufficient) to know the structure of the molecule. There are many ways of relating the molecular function with the structure. Mutation analysis can identify pertinent amino acids of an enzyme, or alternatively structure comparison of the of two similar molecules with different function may lead to understanding which parts are responsible for a functional aspect, or a series of "structural cartoons" - enzyme structure, enzyme plus substrate, enzyme with transition state analog, and enzyme with product - may give insight in the function of a molecule. As an example we will discuss the structure and function of the restriction enzyme BsoBI from Bacillus stearothemzophilus in complex with its cognate DNA. The enzyme forms a unique complex with DNA in that it completely encircles the DNA. The structure reveals the enzyme-DNA contacts, how the DNA is distorted compared with the canonical forms, and elegantly shows how two distinct DNA sequences can be recognized with the same efficiency. Based on the structure we may also propose a hypothesis how the enzymatic mechanism works. The knowledge gained thru studies such as this one can be used to alter the function by changing the molecular structure. Usually this is done by design of inhibitors specifically active against and fitting into an active site of the enzyme of choice. In the case of BsoBI one of the objectives of the study was to alter the enzyme specificity. In bone biology there are many candidates available for molecular study in order to explain, alter, or (temporarily) suspend activity. For example, the understanding of a pathway that negatively regulates bone formation may be a good target for drug design to stimulate bone formation and have good potential as the basis for new countermeasures against bone loss. In principle the same approach may aid muscle atrophy, radiation damage, immune response changes and other risks identified for long-duration Space travel.

[Impact of thyroid diseases on bone].

PubMed

Tsourdi, E; Lademann, F; Siggelkow, H

2018-05-09

Thyroid hormones are key regulators of skeletal development in childhood and bone homeostasis in adulthood, and thyroid diseases have been associated with increased osteoporotic fractures. Hypothyroidism in children leads to an impaired skeletal maturation and mineralization, but an adequate and timely substitution with thyroid hormones stimulates bone growth. Conversely, hyperthyroidism at a young age accelerates skeletal development, but may also cause short stature because of a premature fusion of the growth plates. Hypothyroidism in adults causes an increase in the duration of the remodeling cycle and, thus, leads to low bone turnover and enhanced mineralization, but an association with a higher fracture risk is less well established. In adults, a surplus of thyroid hormones enhances bone turnover, mostly due to an increased bone resorption driven by osteoclasts. Thus, hyperthyroidism is a well-recognized cause of high-bone turnover secondary osteoporosis, resulting in an increased susceptibility to fragility fractures. Subclinical hyperthyroidism, especially resulting from endogenous disease, also has an adverse effect on bone mineral density and is associated with fractures. In most patients with overt or subclinical hyperthyroidism restoration of the euthyroid status reverses bone loss. In postmenopausal women who receive thyroid-stimulating hormone suppression therapy because of thyroid cancer, antiresorptive treatments may be indicated. Overall, extensive data support the importance of a euthyroid status for bone mineral accrual and growth in childhood as well as maintenance of bone health in adulthood.

Histological evaluation of the influence of magnetic field application in autogenous bone grafts in rats.

PubMed

Puricelli, Edela; Dutra, Nardier B; Ponzoni, Deise

2009-01-11

Bone grafts are widely used in oral and maxillofacial reconstruction. The influence of electromagnetic fields and magnets on the endogenous stimulation of target tissues has been investigated. This work aimed to assess the quality of bone healing in surgical cavities filled with autogenous bone grafts, under the influence of a permanent magnetic field produced by in vivo buried devices. Metal devices consisting of commercially pure martensitic stainless steel washers and titanium screws were employed. Thirty male Wistar rats were divided into 3 experimental and 3 control groups. A surgical bone cavity was produced on the right femur, and a bone graft was collected and placed in each hole. Two metallic washers, magnetized in the experimental group but not in the control group, were attached on the borders of the cavity. The animals were sacrificed on postoperative days 15, 45 and 60. The histological analysis of control and experimental samples showed adequate integration of the bone grafts, with intense bone neoformation. On days 45 and 60, a continued influence of the magnetic field on the surgical cavity and on the bone graft was observed in samples from the experimental group. The results showed intense bone neoformation in the experimental group as compared to control animals. The intense extra-cortical bone neoformation observed suggests that the osteoconductor condition of the graft may be more susceptible to stimulation, when submitted to a magnetic field.

Increased bone density in mice lacking the proton receptor, OGR1

PubMed Central

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

Dietary induced serum phenolic acids promote bone growth via p38 MAPK / Beta-Catenin Canonical Wnt signaling

USDA-ARS?s Scientific Manuscript database

Diet and nutritional status are critical factors that influences bone development. In this report, we demonstrate that a mixture of phenolic acids found in the serum of young rats fed blueberries (BB), significantly stimulated osteoblast differentiation, resulting in significantly increased bone mas...

High-fat diet exacerbates bone loss in mice implanted with low-dose slow-release lipopolysaccharide pellets

USDA-ARS?s Scientific Manuscript database

Obesity is associated with chronic up-regulation of inflammatory cytokines which stimulate osteoclast activity and bone resorption. Osteopenia or low bone mass is observed in a variety of physiological conditions with chronic inflammation including aging and post-menopause with estrogen deficiency. ...

Physiological Challenges of Bone Repair

DTIC Science & Technology

2012-12-01

expression, in general, followed the same pattern in both groups, but significantly, lower levels of mRNA for Indian Hedgehog (ihh) and BMP-2 were detected in...the fracture calluses of the older rats. Indian Hedgehog is thought to be involved in chondrogenesis and bone repair, whereas BMP-2 stimulates bone

Ultrasonic and electromagnetic enhancement of a culture of human SAOS-2 osteoblasts seeded onto a titanium plasma-spray surface.

PubMed

Fassina, Lorenzo; Saino, Enrica; Sbarra, Maria Sonia; Visai, Livia; Cusella De Angelis, Maria Gabriella; Mazzini, Giuliano; Benazzo, Francesco; Magenes, Giovanni

2009-06-01

Several studies suggest that the surface coating of titanium could play an important role in bone tissue engineering. In the present study, we have followed a particular biomimetic strategy where ultrasonically or electromagnetically stimulated SAOS-2 human osteoblasts proliferated and built their extracellular matrix on a titanium plasma-spray surface. In comparison with control conditions, the ultrasonic stimulation (average power, 149 mW; frequency, 1.5 MHz) and the electromagnetic stimulation (magnetic field intensity, 2 mT; frequency, 75 Hz) caused higher cell proliferation, and increased surface coating with decorin, osteocalcin, osteopontin, and type I collagen together with higher incorporation of calcium and phosphorus inside the extracellular matrix. The immunofluorescence related to the preceding bone matrix proteins showed their colocalization in the cell-rich areas. The use of the two physical stimulations aimed at obtaining the coating of the rough titanium plasma-spray surface in terms of cell colonization and deposition of extracellular matrix. The superficially cultured biomaterial could be theoretically used, in clinical applications, as an implant for bone repair.

Dynamic Fluid Flow Mechanical Stimulation Modulates Bone Marrow Mesenchymal Stem Cells.

PubMed

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.

Reversing sex steroid deficiency and optimizing skeletal development in the adolescent with gonadal failure.

PubMed

Vanderschueren, Dirk; Vandenput, Liesbeth; Boonen, Steven

2005-01-01

During puberty, the acquisition of skeletal mass and areal bone mineral density (BMD) mainly reflects an increase in bone size (length and perimeters) and not true volumetric BMD. Sexual dimorphism in bone mass and areal BMD is also explained by differences in bone size (longer and wider bones in males) and not by differences in volumetric BMD. Androgens stimulate skeletal growth by activation of the androgen receptor, whereas estrogens (following aromatization of androgens and stimulation of estrogen receptors) have a biphasic effect on skeletal growth during puberty. Recent evidence from clinical cases has shown that many of the growth-promoting effects of the sex steroids are mediated through estrogens rather than androgens. In addition, skeletal maturation and epiphyseal fusion are also estrogen-dependent in both sexes. Nevertheless, independent actions of androgens in these processes also occur. Both sex steroids maintain volumetric BMD during puberty. Androgens interact with the growth hormone (GH)-insulin-like growth factor-I (IGF-I) axis neonatally, resulting in a sexual dimorphic GH pattern during puberty, whereas estrogens stimulate GH and hereby IGF-I in both sexes. Hypogonadism in adolescents impairs not only bone size but also maintenance of volumetric BMD, hereby severely reducing peak areal BMD. Delayed puberty in boys and Turner's syndrome in women impair both bone length and size, reducing areal BMD. Whether volumetric BMD is also reduced and whether fracture risk is increased in these conditions remains controversial. Replacing sex steroids according to a biphasic pattern (starting at low doses and ending at high-normal doses) seems the safest approach to reach targeted height and to optimize bone development.

Numerical simulation of fluid field and in vitro three-dimensional fabrication of tissue-engineered bones in a rotating bioreactor and in vivo implantation for repairing segmental bone defects.

PubMed

Song, Kedong; Wang, Hai; Zhang, Bowen; Lim, Mayasari; Liu, Yingchao; Liu, Tianqing

2013-03-01

In this paper, two-dimensional flow field simulation was conducted to determine shear stresses and velocity profiles for bone tissue engineering in a rotating wall vessel bioreactor (RWVB). In addition, in vitro three-dimensional fabrication of tissue-engineered bones was carried out in optimized bioreactor conditions, and in vivo implantation using fabricated bones was performed for segmental bone defects of Zelanian rabbits. The distribution of dynamic pressure, total pressure, shear stress, and velocity within the culture chamber was calculated for different scaffold locations. According to the simulation results, the dynamic pressure, velocity, and shear stress around the surface of cell-scaffold construction periodically changed at different locations of the RWVB, which could result in periodical stress stimulation for fabricated tissue constructs. However, overall shear stresses were relatively low, and the fluid velocities were uniform in the bioreactor. Our in vitro experiments showed that the number of cells cultured in the RWVB was five times higher than those cultured in a T-flask. The tissue-engineered bones grew very well in the RWVB. This study demonstrates that stress stimulation in an RWVB can be beneficial for cell/bio-derived bone constructs fabricated in an RWVB, with an application for repairing segmental bone defects.

Mutual cancellation between tones presented by air conduction, by bone conduction and by non-osseous (soft tissue) bone conduction.

PubMed

Chordekar, Shai; Kriksunov, Leonid; Kishon-Rabin, Liat; Adelman, Cahtia; Sohmer, Haim

2012-01-01

Auditory sensation can be elicited not only by air conducted (AC) sound or bone conducted (BC) sound, but also by stimulation of soft tissue (STC) sites on the head and neck relatively distant from deeply underlying bone. Tone stimulation by paired combinations of AC with BC (mastoid) and/or with soft tissue conduction produce the same pitch sensation, mutual masking and beats. The present study was designed to determine whether they can also cancel each other. The study was conducted on ten normal hearing subjects. Tones at 2 kHz were presented in paired combinations by AC (insert earphone), by BC (bone vibrator) at the mastoid, and by the same bone vibrator to several STC sites; e.g. the neck, the sterno-cleido-mastoid muscle, the eye, and under the chin, shifting the phases between the pairs. Subjects reported changes in loudness and cancellation. The phase for cancellation differed across subjects. Neck muscle manipulations (changes in head position) led to alterations in the phase at which cancellation was reported. Cancellation was also achieved between pairs of tones to two STC sites. The differing phases for cancellation across subjects and the change in phase accompanying different head positions may be due to the different acoustic impedances of the several tissues in the head and neck. A major component of auditory stimulation by STC may not induce actual skull bone vibrations and may not involve bulk fluid volume displacements. Copyright © 2011 Elsevier B.V. All rights reserved.

The Physiology of Bone Pain. How Much Do We Really Know?

PubMed Central

Nencini, Sara; Ivanusic, Jason J.

2016-01-01

Pain is associated with most bony pathologies. Clinical and experimental observations suggest that bone pain can be derived from noxious stimulation of the periosteum or bone marrow. Sensory neurons are known to innervate the periosteum and marrow cavity, and most of these have a morphology and molecular phenotype consistent with a role in nociception. However, little is known about the physiology of these neurons, and therefore information about mechanisms that generate and maintain bone pain is lacking. The periosteum has received greater attention relative to the bone marrow, reflecting the easier access of the periosteum for experimental assessment. With the electrophysiological preparations used, investigators have been able to record from single periosteal units in isolation, and there is a lot of information available about how they respond to different stimuli, including those that are noxious. In contrast, preparations used to study sensory neurons that innervate the bone marrow have been limited to recording multi-unit activity in whole nerves, and whilst they clearly report responses to noxious stimulation, it is not possible to define responses for single sensory neurons that innervate the bone marrow. There is only limited evidence that peripheral sensory neurons that innervate bone can be sensitized or that they can be activated by multiple stimulus types, and at present this only exists in part for periosteal units. In the central nervous system, it is clear that spinal dorsal horn neurons can be activated by noxious stimuli applied to bone. Some can be sensitized under pathological conditions and may contribute in part to secondary or referred pain associated with bony pathology. Activity related to stimulation of sensory nerves that innervate bone has also been reported in neurons of the spinoparabrachial pathway and the somatosensory cortices, both known for roles in coding information about pain. Whilst these provide some clues as to the way information about bone pain is centrally coded, they need to be expanded to further our understanding of other central territories involved. There is a lot more to learn about the physiology of peripheral sensory neurons that innervate bone and their central projections. PMID:27199772

Normocalcemia is maintained in mice under conditions of calcium malabsorption by vitamin D–induced inhibition of bone mineralization

PubMed Central

Lieben, Liesbet; Masuyama, Ritsuko; Torrekens, Sophie; Van Looveren, Riet; Schrooten, Jan; Baatsen, Pieter; Lafage-Proust, Marie-Hélène; Dresselaers, Tom; Feng, Jian Q.; Bonewald, Lynda F.; Meyer, Mark B.; Pike, J. Wesley; Bouillon, Roger; Carmeliet, Geert

2012-01-01

Serum calcium levels are tightly controlled by an integrated hormone-controlled system that involves active vitamin D [1,25(OH)2D], which can elicit calcium mobilization from bone when intestinal calcium absorption is decreased. The skeletal adaptations, however, are still poorly characterized. To gain insight into these issues, we analyzed the consequences of specific vitamin D receptor (Vdr) inactivation in the intestine and in mature osteoblasts on calcium and bone homeostasis. We report here that decreased intestinal calcium absorption in intestine-specific Vdr knockout mice resulted in severely reduced skeletal calcium levels so as to ensure normal levels of calcium in the serum. Furthermore, increased 1,25(OH)2D levels not only stimulated bone turnover, leading to osteopenia, but also suppressed bone matrix mineralization. This resulted in extensive hyperosteoidosis, also surrounding the osteocytes, and hypomineralization of the entire bone cortex, which may have contributed to the increase in bone fractures. Mechanistically, osteoblastic VDR signaling suppressed calcium incorporation in bone by directly stimulating the transcription of genes encoding mineralization inhibitors. Ablation of skeletal Vdr signaling precluded this calcium transfer from bone to serum, leading to better preservation of bone mass and mineralization. These findings indicate that in mice, maintaining normocalcemia has priority over skeletal integrity, and that to minimize skeletal calcium storage, 1,25(OH)2D not only increases calcium release from bone, but also inhibits calcium incorporation in bone. PMID:22523068

Semicircular Canal Pressure Changes During High-intensity Acoustic Stimulation.

PubMed

Maxwell, Anne K; Banakis Hartl, Renee M; Greene, Nathaniel T; Benichoux, Victor; Mattingly, Jameson K; Cass, Stephen P; Tollin, Daniel J

2017-08-01

Acoustic stimulation generates measurable sound pressure levels in the semicircular canals. High-intensity acoustic stimuli can cause hearing loss and balance disruptions. To examine the propagation of acoustic stimuli to the vestibular end-organs, we simultaneously measured fluid pressure in the cochlea and semicircular canals during both air- and bone-conducted sound presentation. Five full-cephalic human cadaveric heads were prepared bilaterally with a mastoidectomy and extended facial recess. Vestibular pressures were measured within the superior, lateral, and posterior semicircular canals, and referenced to intracochlear pressure within the scala vestibuli with fiber-optic pressure probes. Pressures were measured concurrently with laser Doppler vibrometry measurements of stapes velocity during stimulation with both air- and bone-conduction. Stimuli were pure tones between 100 Hz and 14 kHz presented with custom closed-field loudspeakers for air-conducted sounds and via commercially available bone-anchored device for bone-conducted sounds. Pressures recorded in the superior, lateral, and posterior semicircular canals in response to sound stimulation were equal to or greater in magnitude than those recorded in the scala vestibuli (up to 20 dB higher). The pressure magnitudes varied across canals in a frequency-dependent manner. High sound pressure levels were recorded in the semicircular canals with sound stimulation, suggesting that similar acoustical energy is transmitted to the semicircular canals and the cochlea. Since these intralabyrinthine pressures exceed intracochlear pressure levels, our results suggest that the vestibular end-organs may also be at risk for injury during exposure to high-intensity acoustic stimuli known to cause trauma in the auditory system.

Nell-1-Induced Bone Regeneration in Calvarial Defects

PubMed Central

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

Coating with a Modular Bone Morphogenetic Peptide Promotes Healing of a Bone-Implant Gap in an Ovine Model

PubMed Central

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

Si-Wu-tang extract stimulates bone formation through PI3K/Akt/NF-κB signaling pathways in osteoblasts.

PubMed

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.

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.

CD14 Protein Acts as an Adaptor Molecule for the Immune Recognition of Salmonella Curli Fibers*

PubMed Central

Rapsinski, Glenn J.; Newman, Tiffanny N.; Oppong, Gertrude O.; van Putten, Jos P. M.; Tükel, Çagla

2013-01-01

Amyloids, protein aggregates with a cross β-sheet structure, contribute to inflammation in debilitating disorders, including Alzheimer's disease. Enteric bacteria also produce amyloids, termed curli, contributing to inflammation during infection. It has been demonstrated that curli and β-amyloid are recognized by the immune system via the Toll-like receptor (TLR) 2/TLR1 complex. Here we investigated the role of CD14 in the immune recognition of bacterial amyloids. We used HeLa 57A cells, a human cervical cancer cell line containing a luciferase reporter gene under the control of an NF-κB promoter. When HeLa 57A cells were transiently transfected with combinations of human expression vectors containing genes for TLR2, TLR1, and CD14, membrane-bound CD14 enhanced NF-κB activation through the TLR2/TLR1 complex stimulated with curli fibers or recombinant CsgA, the curli major subunit. Similarly, soluble CD14 augmented the TLR2/TLR1 response to curli fibers in the absence of membrane-bound CD14. We further revealed that IL-6 and nitric oxide production were significantly higher by wild-type (C57BL/6) bone marrow-derived macrophages compared with TLR2-deficient or CD14-deficient bone marrow-derived macrophages when stimulated with curli fibers, recombinant CsgA, or synthetic CsgA peptide, CsgA-R4–5. Binding assays demonstrated that recombinant TLR2, TLR1, and CD14 bound purified curli fibers. Interestingly, CD14-curli interaction was specific to the fibrillar form of the amyloid, as demonstrated by using synthetic CsgA peptides proficient and deficient in fiber formation, respectively. Activation of the TLR2/TLR1/CD14 trimolecular complex by amyloids provides novel insights for innate immunity with implications for amyloid-associated diseases. PMID:23548899

An MRI-based leg model used to simulate biomechanical phenomena during cuff algometry: a finite element study.

PubMed

Manafi-Khanian, Bahram; Arendt-Nielsen, Lars; Graven-Nielsen, Thomas

2016-03-01

Cuff pressure stimulation is applicable for assessing deep-tissue pain sensitivity by exciting a variety of deep-tissue nociceptors. In this study, the relative transfer of biomechanical stresses and strains from the cuff via the skin to the muscle and the somatic tissue layers around bones were investigated. Cuff pressure was applied on the lower leg at three different stimulation intensities (mild pressure to pain). Three-dimensional finite element models including bones and three different layers of deep tissues were developed based on magnetic resonance images (MRI). The skin indentation maps at mild pressure, pain threshold, and intense painful stimulations were extracted from MRI and applied to the model. The mean stress under the cuff position around tibia was 4.6, 4.9 and around fibula 14.8, 16.4 times greater than mean stress of muscle surface in the same section at pain threshold and intense painful stimulations, respectively. At the same stimulation intensities, the mean strains around tibia were 36.4, 42.3 % and around fibula 32.9, 35.0 %, respectively, of mean strain on the muscle surface. Assuming strain as the ideal stimulus for nociceptors the results suggest that cuff algometry is less capable to challenge the nociceptors of tissues around bones as compared to more superficially located muscles.

Activation of adenosine A(3) receptors supports hematopoiesis-stimulating effects of granulocyte colony-stimulating factor in sublethally irradiated mice.

PubMed

Hofer, Michal; Pospísil, Milan; Sefc, Ludek; Dusek, Ladislav; Vacek, Antonín; Holá, Jirina; Hoferová, Zuzana; Streitová, Denisa

2010-08-01

Research areas of 'post-exposure treatment' and 'cytokines and growth factors' have top priority among studies aimed at radiological nuclear threat countermeasures. The experiments were aimed at testing the ability of N(6)-(3-iodobenzyl)adenosine-5'-N-methyluronamide (IB-MECA), an adenosine A(3) receptor agonist, to modulate hematopoiesis in sublethally irradiated mice, when administered alone or in a combination with granulocyte colony-stimulating factor (G-CSF) in a two-day post-irradiation treatment regimen. A complete analysis of hematopoiesis including determination of numbers of bone marrow hematopoietic progenitor and precursor cells, as well as of numbers of peripheral blood cells, was performed. The outcomes of the treatment were assessed at days 3 to 22 after irradiation. IB-MECA alone has been found to induce a significant elevation of numbers of bone marrow granulocyte-macrophage progenitor cells (GM-CFC) and peripheral blood neutrophils. IB-MECA given concomitantly with G-CSF increased significantly bone marrow GM-CFC and erythroid progenitor cells (BFU-E) in comparison with the controls and with animals administered each of the drugs alone. The findings suggest the ability of IB-MECA to stimulate hematopoiesis and to support the hematopoiesis-stimulating effects of G-CSF in sublethally irradiated mice.

Insulin-like growth factor-II regulates bone sialoprotein gene transcription.

PubMed

Choe, Jin; Sasaki, Yoko; Zhou, Liming; Takai, Hideki; Nakayama, Yohei; Ogata, Yorimasa

2016-09-01

Insulin-like growth factor-I and -II (IGF-I and IGF-II) have been found in bone extracts of several different species, and IGF-II is the most abundant growth factor stored in bone. Bone sialoprotein (BSP) is a noncollagenous extracellular matrix glycoprotein associated with mineralized connective tissues. In this study, we have investigated the regulation of BSP transcription by IGF-II in rat osteoblast-like ROS17/2.8 cells. IGF-II (50 ng/ml) increased BSP mRNA and protein levels after 6-h stimulation, and enhanced luciferase activities of the constructs pLUC3 (-116 to +60), pLUC4 (-425 to +60), pLUC5 (-801 to +60) and pLUC6 (-938 to +60). Effects of IGF-II were inhibited by tyrosine kinase, extracellular signal-regulated kinase1/2 and phosphatidylinositol 3-kinase inhibitors, and abrogated by 2-bp mutations in cAMP response element (CRE), FGF2 response element (FRE) and homeodomain protein-binding site (HOX). The results of gel shift assays showed that nuclear proteins binding to CRE, FRE and HOX sites were increased by IGF-II (50 ng/ml) at 3 and 6 h. CREB1, phospho-CREB1, c-Fos and c-Jun antibodies disrupted the formation of the CRE-protein complexes. Dlx5 and Runx2 antibodies disrupted the FRE- and HOX-protein complex formations. These studies therefore demonstrated that IGF-II increased BSP transcription by targeting CRE, FRE and HOX elements in the proximal promoter of the rat BSP gene. Moreover, phospho-CREB1, c-Fos, c-Jun, Dlx5 and Runx2 transcription factors appear to be key regulators of IGF-II effects on BSP transcription.

Algorithm for employing physical forces in metabolic bone diseases.

PubMed

Massari, Leo

2011-04-01

Metabolic bone diseases, especially osteoporosis, demand a multidisciplinary approach. The physical forces find a rationale in the treatment of local alterations in bone-cartilage metabolism. In integrated treatment of vertebral fractures caused by fragility, stimulation with electrical fields has been observed to be effective in reducing pain and improving patients' quality of life.

Engineered decellularized matrices to instruct bone regeneration processes.

PubMed

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.

A novel strontium(II)-modified calcium phosphate bone cement stimulates human-bone-marrow-derived mesenchymal stem cell proliferation and osteogenic differentiation in vitro.

PubMed

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.

Normalization of periodontal tissues in osteopetrotic mib mutant rats, treated with CSF-1

NASA Technical Reports Server (NTRS)

Wojtowicz, A.; Yamauchi, M.; Sotowski, R.; Ostrowski, K.

1998-01-01

The osteopetrotic mib mutation in rats causes defects in the skeletal bone tissue in young animals. These defects, i.e. slow bone remodelling, changes in both crystallinity and mineral content, are transient and undergo normalization, even without any treatment in 6-wk-old animals. Treatment with CSF-1 (colony stimulating factor-1) accelerates the normalization process in skeletal bones. The periodontal tissues around the apices of incisors show abnormalities caused by the slow remodelling process of the mandible bone tissue, the deficiency of osteoclasts and their abnormal morphology, as well as the disorganization of periodontal ligament fibres. In contrast to the skeletal tissues, these abnormalities would not undergo spontaneous normalization. Under treatment with colony stimulating factor 1 (CSF-1), the primitive bone trabeculae of mandible are resorbed and the normalization of the number of osteoclasts and their cytology occurs. The organization of the periodontal ligament fibres is partially restored, resembling the histological structure of the normal one.

Measurement of stapes vibration in Human temporal bones by round window stimulation using a 3-coil transducer.

PubMed

Shin, Dong Ho; Kim, Dong Wook; Lim, Hyung Gyu; Jung, Eui Sung; Seong, Ki Woong; Lee, Jyung Hyun; Kim, Myoung Nam; Cho, Jin Ho

2014-01-01

Round window placement of a 3-coil transducer offers a new approach for coupling an implantable hearing aid to the inner ear. The transducer exhibits high performance at low-frequencies. One remarkable feature of the 3-coil transducer is that it minimizes leakage flux. Thus, the transducer, which consists of two permanent magnets and three coils, can enhance vibrational displacement. In human temporal bones, stapes vibration was observed by laser Doppler vibrometer in response to round window stimulation using the 3-coil transducer. Coupling between the 3-coil transducer and the round window was connected by a wire-rod. The stimulation created stapes velocity when the round window stimulated. Performance evaluation was conducted by measuring stapes velocity. To verify the performance of the 3-coil transducer, stapes velocity for round window and tympanic membrane stimulation were compared, respectively. Stapes velocity by round window stimulation using the 3-coil transducer was approximately 14 dB higher than that achieved by tympanic membrane stimulation. The study shows that 3-coil transducer is suitable for implantable hearing aids.

Direct current stimulation of titanium interbody fusion devices in primates.

PubMed

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.

Laser-modified titanium surfaces enhance the osteogenic differentiation of human mesenchymal stem cells.

PubMed

Bressel, Tatiana A B; de Queiroz, Jana Dara Freires; Gomes Moreira, Susana Margarida; da Fonseca, Jéssyca T; Filho, Edson A; Guastaldi, Antônio Carlos; Batistuzzo de Medeiros, Silvia Regina

2017-11-28

Titanium surfaces have been modified by various approaches with the aim of improving the stimulation of osseointegration. Laser beam (Yb-YAG) treatment is a controllable and flexible approach to modifying surfaces. It creates a complex surface topography with micro and nano-scaled patterns, and an oxide layer that can improve the osseointegration of implants, increasing their usefulness as bone implant materials. Laser beam irradiation at various fluences (132, 210, or 235 J/cm 2 ) was used to treat commercially pure titanium discs to create complex surface topographies. The titanium discs were investigated by scanning electron microscopy, X-ray diffraction, and measurement of contact angles. The surface generated at a fluence of 235 J/cm 2 was used in the biological assays. The behavior of mesenchymal stem cells from an umbilical cord vein was evaluated using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, a mineralization assay, and an alkaline phosphatase activity assay and by carrying out a quantitative real-time polymerase chain reaction for osteogenic markers. CHO-k1 cells were also exposed to titanium discs in the MTT assay. The best titanium surface was that produced by laser beam irradiation at 235 J/cm 2 fluence. Cell proliferation analysis revealed that the CHO-k1 and mesenchymal stem cells behaved differently. The laser-processed titanium surface increased the proliferation of CHO-k1 cells, reduced the proliferation of mesenchymal stem cells, upregulated the expression of the osteogenic markers, and enhanced alkaline phosphatase activity. The laser-treated titanium surface modulated cellular behavior depending on the cell type, and stimulated osteogenic differentiation. This evidence supports the potential use of laser-processed titanium surfaces as bone implant materials, and their use in regenerative medicine could promote better outcomes.

Bone regeneration: molecular and cellular interactions with calcium phosphate ceramics

PubMed Central

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

Rapidly Growing Brtl/+ Mouse Model of Osteogenesis Imperfecta Improves Bone Mass and Strength with Sclerostin Antibody Treatment

PubMed Central

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

Histological evaluation of the influence of magnetic field application in autogenous bone grafts in rats

PubMed Central

Puricelli, Edela; Dutra, Nardier B; Ponzoni, Deise

2009-01-01

Background Bone grafts are widely used in oral and maxillofacial reconstruction. The influence of electromagnetic fields and magnets on the endogenous stimulation of target tissues has been investigated. This work aimed to assess the quality of bone healing in surgical cavities filled with autogenous bone grafts, under the influence of a permanent magnetic field produced by in vivo buried devices. Methods Metal devices consisting of commercially pure martensitic stainless steel washers and titanium screws were employed. Thirty male Wistar rats were divided into 3 experimental and 3 control groups. A surgical bone cavity was produced on the right femur, and a bone graft was collected and placed in each hole. Two metallic washers, magnetized in the experimental group but not in the control group, were attached on the borders of the cavity. Results The animals were sacrificed on postoperative days 15, 45 and 60. The histological analysis of control and experimental samples showed adequate integration of the bone grafts, with intense bone neoformation. On days 45 and 60, a continued influence of the magnetic field on the surgical cavity and on the bone graft was observed in samples from the experimental group. Conclusion The results showed intense bone neoformation in the experimental group as compared to control animals. The intense extra-cortical bone neoformation observed suggests that the osteoconductor condition of the graft may be more susceptible to stimulation, when submitted to a magnetic field. PMID:19134221

Role of reduced insulin-stimulated bone blood flow in the pathogenesis of metabolic insulin resistance and diabetic bone fragility.

PubMed

Hinton, Pamela S

2016-08-01

Worldwide, 387 million adults live with type 2 diabetes (T2D) and an additional 205 million cases are projected by 2035. Because T2D has numerous complications, there is significant morbidity and mortality associated with the disease. Identification of early events in the pathogenesis of insulin resistance and T2D might lead to more effective treatments that would mitigate health and monetary costs. Here, we present our hypothesis that impaired bone blood flow is an early event in the pathogenesis of whole-body metabolic insulin resistance that ultimately leads to T2D. Two recent developments in different fields form the basis for this hypothesis. First, reduced vascular function has been identified as an early event in the development of T2D. In particular, before the onset of tissue or whole body metabolic insulin resistance, insulin-stimulated, endothelium-mediated skeletal muscle blood flow is impaired. Insulin resistance of the vascular endothelium reduces delivery of insulin and glucose to skeletal muscle, which leads to tissue and whole-body metabolic insulin resistance. Second is the paradigm-shifting discovery that the skeleton has an endocrine function that is essential for maintenance of whole-body glucose homeostasis. Specifically, in response to insulin signaling, osteoblasts secret osteocalcin, which stimulates pancreatic insulin production and enhances insulin sensitivity in skeletal muscle, adipose, and liver. Furthermore, the skeleton is not metabolically inert, but contributes to whole-body glucose utilization, consuming 20% that of skeletal muscle and 50% that of white adipose tissue. Without insulin signaling or without osteocalcin activity, experimental animals become hyperglycemic and insulin resistant. Currently, it is not known if insulin-stimulated, endothelium-mediated blood flow to bone plays a role in the development of whole body metabolic insulin resistance. We hypothesize that it is a key, early event. Microvascular dysfunction is a primary cause of diabetic nephropathy, retinopathy and neuropathy and poor bone blood flow is associated with bone loss. Therefore, we also hypothesize that dysfunction of the bone vascular endothelium contributes to the bone fragility observed in T2D. The most important consequence of our-dual hypothesis is the public health significance. Namely, identification of the proximal cause of T2D and associated bone complications allows pursuit of the appropriate therapeutic target to treat and prevent T2D. If our hypothesis that reduced bone blood flow is an early event in the pathogenesis of T2D and diabetic bone fragility is correct, then the endothelium of the bone vasculature should be a therapeutic target. Copyright © 2016 Elsevier Ltd. All rights reserved.

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.

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.

Sex steroids during bone growth: a comparative study between mouse models for hypogonadal and senile osteoporosis.

PubMed

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.

Trabecular bone adaptation to low-magnitude high-frequency loading in microgravity.

PubMed

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.

Alendronate promotes bone formation by inhibiting protein prenylation in osteoblasts in rat tooth replantation model.

PubMed

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.

[The effect of lithium carbonate on the leukocyte count following ionizing radiation. 4. The effect of lithium carbonate on the activation of granulocytes].

PubMed

Wolf, G; Müller, G M; Kehrberg, G

1989-01-01

From numerous investigations it is known that lithium carbonate promotes granulocytopoiesis by stimulation of CSF (colony stimulating factor) in bone marrow. To prove if no immature, in their functions restricted cells are delivered from bone marrow, the activity of granulocytes was tested in vitro in patients with lithium therapy. It could be seen that granulocytes of peripheral blood show an increased in-vitro-activation after lithium influence in vivo.

Peptide drugs accelerate BMP‐2‐induced calvarial bone regeneration and stimulate osteoblast differentiation through mTORC1 signaling

PubMed Central

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

A morphometric study of bone surfaces and skin reactions after stimulation with static magnetic fields in rats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Linder-Aronson, S.; Lindskog, S.

1991-01-01

The present investigation was undertaken to measure any bone surface changes after stimulation with orthodontic magnets and, furthermore, to examine the soft tissue in immediate contact with the magnets. Both distal parts of the tibial hind legs in six groups of young rats were fitted with devices holding two orthodontic magnets in the experimental legs and similar devices without magnets in the control legs. The animals were killed after 2, 3, and 4 weeks. Morphometric evaluation showed significant increases in resorbing areas after 3 and 4 weeks. Similarly, a reduction was evident in the number of epithelial cells under themore » areas where the magnets had been applied. These findings indicate that the stimulation of bone resorption in the present study may have been caused by inhibition of the bone-lining osteoblasts. This proposition is supported by the apparent inhibitory effect of the magnetic fields on epithelial recycling that was seen as a reduced thickness of the epithelium under the magnets. Consequently, static magnetic fields should be used with care in orthodontic practice until a more complete understanding of their mechanism of action has been established.« less

A morphometric study of bone surfaces and skin reactions after stimulation with static magnetic fields in rats.

PubMed

Linder-Aronson, S; Lindskog, S

1991-01-01

The present investigation was undertaken to measure any bone surface changes after stimulation with orthodontic magnets and, furthermore, to examine the soft tissue in immediate contact with the magnets. Both distal parts of the tibial hind legs in six groups of young rats were fitted with devices holding two orthodontic magnets in the experimental legs and similar devices without magnets in the control legs. The animals were killed after 2, 3, and 4 weeks. Morphometric evaluation showed significant increases in resorbing areas after 3 and 4 weeks. Similarly, a reduction was evident in the number of epithelial cells under the areas where the magnets had been applied. These findings indicate that the stimulation of bone resorption in the present study may have been caused by inhibition of the bone-lining osteoblasts. This proposition is supported by the apparent inhibitory effect of the magnetic fields on epithelial recycling that was seen as a reduced thickness of the epithelium under the magnets. Consequently, static magnetic fields should be used with care in orthodontic practice until a more complete understanding of their mechanism of action has been established.

Bone and Muscle: Interactions beyond Mechanical

PubMed Central

Brotto, Marco

2015-01-01

The musculoskeletal system is significantly more complex than portrayed by traditional reductionist approaches that have focused on and studied the components of this system separately. While bone and skeletal muscle are the two largest tissues within this system, this system also includes tendons, ligaments, cartilage, joints and other connective tissue along with vascular and nervous tissue. Because the main function of this system is locomotion, the mechanical interaction among the major players of this system is essential for the many shapes and forms observed in vertebrates and even in invertebrates. Thus, it is logical that the mechanical coupling theories of musculoskeletal development exert a dominant influence on our understanding of the biology of the musculoskeletal system, because these relationships are relatively easy to observe, measure, and perturb. Certainly much less recognized is the molecular and biochemical interaction among the individual players of the musculoskeletal system. In this brief review article, we first introduce some of the key reasons why the mechanical coupling theory has dominated our view of bone-muscle interactions followed by summarizing evidence for the secretory nature of bones and muscles. Finally, a number of highly physiological questions that cannot be answered by the mechanical theories alone will be raised along with different lines of evidence that support both a genetic and a biochemical communication between bones and muscles. It is hoped that these discussions will stimulate new insights into this fertile and promising new way of defining the relationships between these closely related tissues. Understanding the cellular and molecular mechanisms responsible for biochemical communication between bone and muscle is important not only from a basic research perspective but also as a means to identify potential new therapies for bone and muscle diseases, especially for when they co-exist. PMID:26453500

Synergistic effect of scaffold composition and dynamic culturing environment in multilayered systems for bone tissue engineering.

PubMed

Rodrigues, Márcia T; Martins, Albino; Dias, Isabel R; Viegas, Carlos A; Neves, Nuno M; Gomes, Manuela E; Reis, Rui L

2012-11-01

Bone extracellular matrix (ECM) is composed of mineralized collagen fibrils which support biological apatite nucleation that participates in bone outstanding properties. Understanding and mimicking bone morphological and physiological parameters at a biological scale is a major challenge in tissue engineering scaffolding. Using emergent (nano)technologies scaffold designing may be critically improved, enabling highly functional tissue substitutes for bone applications. This study aims to develop novel biodegradable composite scaffolds of tricalcium phosphate (TCPs) and electrospun nanofibers of poly(ϵ-caprolactone) (PCL), combining TCPs osteoconductivity with PCL biocompatibility and elasticity, mimicking bone structure and composition. We hypothesized that scaffolds with such structure/composition would stimulate the proliferation and differentiation of bone marrow stromal cells (BMSCs) towards the osteogenic phenotype. Composite scaffolds, developed by electrospining using consecutive stacked layers of PCL and TCPs, were characterized by FTIR spectroscopy, X-Ray diffraction and scanning electronic microscopy. Cellular behavior was assessed in goat BMSCs seeded onto composite scaffolds and cultured in static or dynamic conditions, using basal or osteogenic media during 7, 14 or 21 days. Cellular proliferation was quantified and osteogenic differentiation confirmed by alkaline phosphatase activity, alizarin red staining and immunocytochemistry for osteocalcin and collagen I. Results suggest that PCL-TCP scaffolds provide a 3D support for gBMSCs proliferation and osteogenic differentiation with production of ECM. TCPs positively stimulate the osteogenic process, especially under dynamic conditions, where PCL-TCP scaffolds are sufficient to promote osteogenic differentiation even in basal medium conditions. The enhancement of the osteogenic potential in dynamic conditions evidences the synergistic effect of scaffold composition and dynamic stimulation in gBMSCs osteogenic differentiation. Copyright © 2012 John Wiley & Sons, Ltd.

Oral feeding with polyunsaturated fatty acids fosters hematopoiesis and thrombopoiesis in healthy and bone marrow-transplanted mice.

PubMed

Limbkar, Kedar; Dhenge, Ankita; Jadhav, Dipesh D; Thulasiram, Hirekodathakallu V; Kale, Vaijayanti; Limaye, Lalita

2017-09-01

Hematopoietic stem cells play the vital role of maintaining appropriate levels of cells in blood. Therefore, regulation of their fate is essential for their effective therapeutic use. Here we report the role of polyunsaturated fatty acids (PUFAs) in regulating hematopoiesis which has not been explored well so far. Mice were fed daily for 10 days with n-6/n-3 PUFAs, viz. linoleic acid (LA), arachidonic acid (AA), alpha-linolenic acid and docosahexanoic acid (DHA) in four separate test groups with phosphate-buffered saline fed mice as control set. The bone marrow cells of PUFA-fed mice showed a significantly higher hematopoiesis as assessed using side population, Lin-Sca-1 + ckit+, colony-forming unit (CFU), long-term culture, CFU-spleen assay and engraftment potential as compared to the control set. Thrombopoiesis was also stimulated in PUFA-fed mice. A combination of DHA and AA was found to be more effective than when either was fed individually. Higher incorporation of PUFAs as well as products of their metabolism was observed in the bone marrow cells of PUFA-fed mice. A stimulation of the Wnt, CXCR4 and Notch1 pathways was observed in PUFA-fed mice. The clinical relevance of this study was evident when bone marrow-transplanted recipient mice, which were fed with PUFAs, showed higher engraftment of donor cells, suggesting that the bone marrow microenvironment may also be stimulated by feeding with PUFAs. These data indicate that oral administration of PUFAs in mice stimulates hematopoiesis and thrombopoiesis and could serve as a valuable supplemental therapy in situations of hematopoietic failure. Copyright © 2017 Elsevier Inc. All rights reserved.

Effects of spaceflight on levels and activity of immune cells

NASA Technical Reports Server (NTRS)

Sonnenfeld, Gerald; Berry, Wallace D.; Mandel, Adrian D.; Konstantinova, Irena V.; Taylor, Gerald R.

1990-01-01

Experiments were carried out on cells from rats that had been flown on Soviet Biosputnik Cosmos 1887 to explore the effects of speceflight on immune responses. Rat bone marrow cells were examined for their response to colony stimulating factor-M. Rat spleen and bone marrow cells were stained with antibodies directed against cell surface antigenic markers. The results of the studies indicate that bone marrow cells from flown rats showed a decreased response to colony stimulating factor. There was a higher percentage of spleen cells from flown rats staining positively for pan-T-cell, suppressor-T-cell, and interleukin-2 receptor cell surface antigens. A small increase in the percentage of cells staining positively for helper-T-cell antigens was also noted. In addition, a higher percentage of cells that appeared to be part of the myelogenous population of bone marrow cells from flown rats stained positively for surface immunoglobulin.

Management of bisphosphonate-related osteonecrosis of the jaw with a platelet-rich fibrin membrane: technical report.

PubMed

Soydan, Sıdıka Sinem; Uckan, Sina

2014-02-01

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is a challenging complication resulting from the long-term application of bisphosphonates. In most cases, BRONJ occurs after a surgical procedure involving the jawbone. Currently, the management of BRONJ remains controversial, and there is no definitive treatment other than palliative methods. Platelet-rich fibrin (PRF) represents a relatively new biotechnology for the stimulation and acceleration of tissue healing and bone regeneration. This technical note describes the total closure of moderate bone exposure in persistent BRONJ in 2 weeks with a double-layer PRF membrane. PRF may stimulate gingival healing and act as a barrier membrane between the alveolar bone and the oral cavity. PRF may offer a fast, easy, and effective alternative method for the closure of bone exposure in BRONJ. Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Nonlinear electric reaction arising in dry bone subjected to 4-point bending

NASA Astrophysics Data System (ADS)

Murasawa, Go; Cho, Hideo; Ogawa, Kazuma

2007-04-01

Bone is a smart, self-adaptive and also partly self-repairing tissue. In recent years, many researchers seek to find how to give the effective mechanical stimulation to bone, because it is the predominant loading that determines the bone shape and macroscopic structure. However, the trial of regeneration of bone is still under way. On the other hand, it has been known that electrical potential generates from bone by mechanical stimulation (Yasuda, 1977; Williams, 1982; Starkebaum, 1979; Cochran, 1968; Lanyon, 1977; Salzstein, 1987a,b; Friedenberg, 1966). This is called "stress-generated potential (SGP)". The process of information transfer between "strain" and "cells" is not still clear. But, there is some possibility that SGP has something to do with the process of information transfer. If the electrical potential is more clear under some mechanical loadings, we will be able to regenerate bone artificially and freely. Therefore, it is important to investigate SGP in detail. The aim of present study is to investigate the electric reaction arising in dry bone subjected to mechanical loadings at high amplitude and low frequency strain. Firstly, specimen is fabricated from femur of cow. Next, the speeds of wave propagation in bone are tried to measure by laser ultra sonic technique and wavelet transform, because these have relationship with bone density. Secondary, 4-point bending test is conducted up to fracture. Then, electric reaction arising in bone is measured during loading. Finally, cyclic 4-point bending tests are conducted to investigate the electric reaction arising in bone at low frequency strain.

Stimulation of host bone marrow stromal cells by sympathetic nerves promotes breast cancer bone metastasis in mice.

PubMed

Campbell, J Preston; Karolak, Matthew R; Ma, Yun; Perrien, Daniel S; Masood-Campbell, S Kathryn; Penner, Niki L; Munoz, Steve A; Zijlstra, Andries; Yang, Xiangli; Sterling, Julie A; Elefteriou, Florent

2012-07-01

Bone and lung metastases are responsible for the majority of deaths in patients with breast cancer. Following treatment of the primary cancer, emotional and psychosocial factors within this population precipitate time to recurrence and death, however the underlying mechanism(s) remain unclear. Using a mouse model of bone metastasis, we provide experimental evidence that activation of the sympathetic nervous system, which is one of many pathophysiological consequences of severe stress and depression, promotes MDA-231 breast cancer cell colonization of bone via a neurohormonal effect on the host bone marrow stroma. We demonstrate that induction of RANKL expression in bone marrow osteoblasts, following β2AR stimulation, increases the migration of metastatic MDA-231 cells in vitro, independently of SDF1-CXCR4 signaling. We also show that the stimulatory effect of endogenous (chronic stress) or pharmacologic sympathetic activation on breast cancer bone metastasis in vivo can be blocked with the β-blocker propranolol, and by knockdown of RANK expression in MDA-231 cells. These findings indicate that RANKL promotes breast cancer cell metastasis to bone via its pro-migratory effect on breast cancer cells, independently of its effect on bone turnover. The emerging clinical implication, supported by recent epidemiological studies, is that βAR-blockers and drugs interfering with RANKL signaling, such as Denosumab, could increase patient survival if used as adjuvant therapy to inhibit both the early colonization of bone by metastatic breast cancer cells and the initiation of the "vicious cycle" of bone destruction induced by these cells.

Human osteocalcin and bone sialoprotein mediating osteomimicry of prostate cancer cells: role of cAMP-dependent protein kinase A signaling pathway.

PubMed

Huang, Wen-Chin; Xie, Zhihui; Konaka, Hiroyuki; Sodek, Jaro; Zhau, Haiyen E; Chung, Leland W K

2005-03-15

Osteocalcin and bone sialoprotein are the most abundant noncollagenous bone matrix proteins expressed by osteoblasts. Surprisingly, osteocalcin and bone sialoprotein are also expressed by malignant but not normal prostate epithelial cells. The purpose of this study is to investigate how osteocalcin and bone sialoprotein expression is regulated in prostate cancer cells. Our investigation revealed that (a) human osteocalcin and bone sialoprotein promoter activities in an androgen-independent prostate cancer cell line of LNCaP lineage, C4-2B, were markedly enhanced 7- to 12-fold in a concentration-dependent manner by conditioned medium collected from prostate cancer and bone stromal cells. (b) Deletion analysis of human osteocalcin and bone sialoprotein promoter regions identified cyclic AMP (cAMP)-responsive elements (CRE) as the critical determinants for conditioned medium-mediated osteocalcin and bone sialoprotein gene expression in prostate cancer cells. Consistent with these results, the protein kinase A (PKA) pathway activators forskolin and dibutyryl cAMP and the PKA pathway inhibitor H-89, respectively, increased or repressed human osteocalcin and bone sialoprotein promoter activities. (c) Electrophoretic mobility shift assay showed that conditioned medium-mediated stimulation of human osteocalcin and bone sialoprotein promoter activities occurs through increased interaction between CRE and CRE-binding protein. (d) Conditioned medium was found to induce human osteocalcin and bone sialoprotein promoter activities via increased CRE/CRE-binding protein interaction in a cell background-dependent manner, with marked stimulation in selected prostate cancer but not bone stromal cells. Collectively, these results suggest that osteocalcin and bone sialoprotein expression is coordinated and regulated through cAMP-dependent PKA signaling, which may define the molecular basis of the osteomimicry exhibited by prostate cancer cells.

Alteration of mineral crystallinity and collagen cross-linking of bones in osteopetrotic toothless (tl/tl) rats and their improvement after treatment with colony stimulating factor-1

NASA Technical Reports Server (NTRS)

Wojtowicz, A.; Dziedzic-Goclawska, A.; Kaminski, A.; Stachowicz, W.; Wojtowicz, K.; Marks, S. C. Jr; Yamauchi, M.

1997-01-01

A common feature of various types of mammalian osteopetroses is a marked increase in bone mass accompanied by spontaneous bone fractures. The toothless (tl/tl) rat osteopetrotic mutation is characterized by drastically reduced bone resorption due to a profound deficiency of osteoclasts and their precursors. An altered bone morphology has also been observed. The mutants cannot be cured by bone marrow transplantation, but skeletal defects are greatly reduced after treatment with colony stimulating factor 1 (CSF-1). The objectives of this study were to characterize mineral and collagen matrices in cancellous and compact bone isolated from long bones of 6-week-old normal littermates, tl/tl osteopetrotic mutants and mutants (tl/tl) treated with CSF-1. There were no differences in bone mineral content, but a significant decrease in the crystallinity of mineral evaluated by the method based on electron paramagnetic resonance spectrometry was observed in all bones of tl/tl mutants as compared to that of controls. Within the collagen matrix, slight decreases in the labile cross-links, but significant increases in the content of the stable cross-links, pyridinoline, and deoxypyridinoline, were observed in both cancellous and compact bone of osteopetrotic mutants. In tl/tl mutants treated with human recombinant CSF-1, the normalization of the crystallinity of bone mineral as well as collagen cross-links was found. Our results indicate that remodeling of bone matrix in tl/tl mutants is highly suppressed, but that after treatment with CSF-1, this activity recovers significantly. Taken together, these data provide further support for the hypothesis that CSF-1 is an essential factor for normal osteoclast differentiation and bone remodelling.

Anti-osteoporotic activity of harpagide by regulation of bone formation in osteoblast cell culture and ovariectomy-induced bone loss mouse models.

PubMed

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.

Rapid prototyping for tissue-engineered bone scaffold by 3D printing and biocompatibility study.

PubMed

He, Hui-Yu; Zhang, Jia-Yu; Mi, Xue; Hu, Yang; Gu, Xiao-Yu

2015-01-01

The prototyping of tissue-engineered bone scaffold (calcined goat spongy bone-biphasic ceramic composite/PVA gel) by 3D printing was performed, and the biocompatibility of the fabricated bone scaffold was studied. Pre-designed STL file was imported into the GXYZ303010-XYLE 3D printing system, and the tissue-engineered bone scaffold was fabricated by 3D printing using gel extrusion. Rabbit bone marrow stromal cells (BMSCs) were cultured in vitro and then inoculated to the sterilized bone scaffold obtained by 3D printing. The growth of rabbit BMSCs on the bone scaffold was observed under the scanning electron microscope (SEM). The effect of the tissue-engineered bone scaffold on the proliferation and differentiation of rabbit BMSCs using MTT assay. Universal testing machine was adopted to test the tensile strength of the bone scaffold. The leachate of the bone scaffold was prepared and injected into the New Zealand rabbits. Cytotoxicity test, acute toxicity test, pyrogenic test and intracutaneous stimulation test were performed to assess the biocompatibility of the bone scaffold. Bone scaffold manufactured by 3D printing had uniform pore size with the porosity of about 68.3%. The pores were well interconnected, and the bone scaffold showed excellent mechanical property. Rabbit BMSCs grew and proliferated on the surface of the bone scaffold after adherence. MTT assay indicated that the proliferation and differentiation of rabbit BMSCs on the bone scaffold did not differ significantly from that of the cells in the control. In vivo experiments proved that the bone scaffold fabricated by 3D printing had no acute toxicity, pyrogenic reaction or stimulation. Bone scaffold manufactured by 3D printing allows the rabbit BMSCs to adhere, grow and proliferate and exhibits excellent biomechanical property and high biocompatibility. 3D printing has a good application prospect in the prototyping of tissue-engineered bone scaffold.

Rapid prototyping for tissue-engineered bone scaffold by 3D printing and biocompatibility study

PubMed Central

He, Hui-Yu; Zhang, Jia-Yu; Mi, Xue; Hu, Yang; Gu, Xiao-Yu

2015-01-01

The prototyping of tissue-engineered bone scaffold (calcined goat spongy bone-biphasic ceramic composite/PVA gel) by 3D printing was performed, and the biocompatibility of the fabricated bone scaffold was studied. Pre-designed STL file was imported into the GXYZ303010-XYLE 3D printing system, and the tissue-engineered bone scaffold was fabricated by 3D printing using gel extrusion. Rabbit bone marrow stromal cells (BMSCs) were cultured in vitro and then inoculated to the sterilized bone scaffold obtained by 3D printing. The growth of rabbit BMSCs on the bone scaffold was observed under the scanning electron microscope (SEM). The effect of the tissue-engineered bone scaffold on the proliferation and differentiation of rabbit BMSCs using MTT assay. Universal testing machine was adopted to test the tensile strength of the bone scaffold. The leachate of the bone scaffold was prepared and injected into the New Zealand rabbits. Cytotoxicity test, acute toxicity test, pyrogenic test and intracutaneous stimulation test were performed to assess the biocompatibility of the bone scaffold. Bone scaffold manufactured by 3D printing had uniform pore size with the porosity of about 68.3%. The pores were well interconnected, and the bone scaffold showed excellent mechanical property. Rabbit BMSCs grew and proliferated on the surface of the bone scaffold after adherence. MTT assay indicated that the proliferation and differentiation of rabbit BMSCs on the bone scaffold did not differ significantly from that of the cells in the control. In vivo experiments proved that the bone scaffold fabricated by 3D printing had no acute toxicity, pyrogenic reaction or stimulation. Bone scaffold manufactured by 3D printing allows the rabbit BMSCs to adhere, grow and proliferate and exhibits excellent biomechanical property and high biocompatibility. 3D printing has a good application prospect in the prototyping of tissue-engineered bone scaffold. PMID:26380018

Effect of Magnolol on the Function of Osteoblastic MC3T3-E1 Cells

PubMed Central

Kwak, Eun Jung; Lee, Young Soon; Choi, Eun Mi

2012-01-01

Objectives. In the present study, the ability of magnolol, a hydroxylated biphenyl compound isolated from Magnolia officinalis, to stimulate osteoblast function and inhibit the release of bone-resorbing mediators was investigated in osteoblastic MC3T3-E1 cells. Methods. Osteoblast function was measured by cell growth, alkaline phosphatase activity, collagen synthesis, and mineralization. Glutathione content was also measured in the cells. Bone-resorbing cytokines, receptor activator of nuclear factor-κB ligand (RANKL), TNF-α, and IL-6 were measured with an enzyme immunoassay system. Results. Magnolol caused a significant elevation of cell growth, alkaline phosphatase activity, collagen synthesis, mineralization, and glutathione content in the cells (P < 0.05). Skeletal turnover is orchestrated by a complex network of regulatory factors. Among cytokines, RANKL, TNF-α, and IL-6 were found to be key osteoclastogenetic molecules produced by osteoblasts. Magnolol significantly (P < 0.05) decreased the production of osteoclast differentiation inducing factors such as RANKL, TNF-α, and IL-6 in the presence of antimycin A, which inhibits mitochondrial electron transport and has been used as an ROS generator. Conclusion. Magnolol might be a candidate as an agent for the prevention of bone disorders such as osteoporosis. PMID:22474400

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.

Recent progresses in gene delivery-based bone tissue engineering.

PubMed

Lu, Chia-Hsin; Chang, Yu-Han; Lin, Shih-Yeh; Li, Kuei-Chang; Hu, Yu-Chen

2013-12-01

Gene therapy has converged with bone engineering over the past decade, by which a variety of therapeutic genes have been delivered to stimulate bone repair. These genes can be administered via in vivo or ex vivo approach using either viral or nonviral vectors. This article reviews the fundamental aspects and recent progresses in the gene therapy-based bone engineering, with emphasis on the new genes, viral vectors and gene delivery approaches. © 2013.

Oncostatin M promotes bone formation independently of resorption when signaling through leukemia inhibitory factor receptor in mice

PubMed Central

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

Fluorosis increases the risk of postmenopausal osteoporosis by stimulating interferon γ.

PubMed

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.

Role of whole bone marrow, whole bone marrow cultured cells, and mesenchymal stem cells in chronic wound healing.

PubMed

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.

Tumor Necrosis Factor α Stimulates Osteoclast Differentiation by a Mechanism Independent of the Odf/Rankl–Rank Interaction

PubMed Central

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

Differential magnesium implant corrosion coat formation and contribution to bone bonding.

PubMed

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.

Bone morphogenetic protein 9 (BMP9) induces effective bone formation from reversibly immortalized multipotent adipose-derived (iMAD) mesenchymal stem cells.

PubMed

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.

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.

The control of human mesenchymal cell differentiation using nanoscale symmetry and disorder

NASA Astrophysics Data System (ADS)

Dalby, Matthew J.; Gadegaard, Nikolaj; Tare, Rahul; Andar, Abhay; Riehle, Mathis O.; Herzyk, Pawel; Wilkinson, Chris D. W.; Oreffo, Richard O. C.

2007-12-01

A key tenet of bone tissue engineering is the development of scaffold materials that can stimulate stem cell differentiation in the absence of chemical treatment to become osteoblasts without compromising material properties. At present, conventional implant materials fail owing to encapsulation by soft tissue, rather than direct bone bonding. Here, we demonstrate the use of nanoscale disorder to stimulate human mesenchymal stem cells (MSCs) to produce bone mineral in vitro, in the absence of osteogenic supplements. This approach has similar efficiency to that of cells cultured with osteogenic media. In addition, the current studies show that topographically treated MSCs have a distinct differentiation profile compared with those treated with osteogenic media, which has implications for cell therapies.

Transforming growth factor-β synthesized by stromal cells and cancer cells participates in bone resorption induced by oral squamous cell carcinoma

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

Intraoperative identification of the facial nerve by needle electromyography stimulation with a burr

PubMed Central

KHAMGUSHKEEVA, N.N.; ANIKIN, I.A.; KORNEYENKOV, A.A.

2016-01-01

The purpose of this research is to improve the safety of surgery for patients with a pathology of the middle and inner ear by preventing damage to the facial nerve by conducting intraoperative monitoring of the facial nerve by needle electromyography with continuous stimulation with a burr. Patients and Methods The clinical part of the prospective study was carried out on 48 patients that were diagnosed with suppurative otitis media. After the surgery with intraoperative monitoring, the facial nerve with an intact bone wall was stimulated electrically in the potentially dangerous places of damage. Minimum (threshold) stimulation (mA) of the facial nerve with a threshold event of 100 μV was used to register EMG events. The anatomical part of the study was carried out on 30 unformalinized cadaver temporal bones from adult bodies. The statistical analysis of obtained data was carried out with parametric methods (Student’s t-test), non-parametric correlation (Spearman’s method) and regression analysis. Results It was found that 1 mA of threshold amperage corresponded to 0.8 mm thickness of the bone wall of the facial canal. Values of transosseous threshold stimulation in potentially dangerous sections of the injury to the facial nerve were obtained. Conclusion These data lower the risk of paresis (paralysis) of the facial muscles during otologic surgery. PMID:27142821

Evaluation of bone repair after application of a norbixin membrane scaffold with and without laser photobiomodulation (λ 780 nm).

PubMed

Alves, Adrielle Martins Monteiro; de Miranda Fortaleza, Lílian Melo; Filho, Antonio Luiz Martins Maia; Ferreira, Danniel Cabral Leão; da Costa, Charllyton Luis Sena; Viana, Vicente Galber Freitas; Santos, José Zilton Lima Verde; de Oliveira, Rauirys Alencar; de Meira Gusmão, Gustavo Oliveira; Soares, Luís Eduardo Silva

2018-05-04

Biocompatible membranes are widely used in medicine to stimulate bone repair. Several studies have demonstrated that laser photobiomodulation (PBM) also stimulates osteoblast proliferation and osteogenesis at the fracture site, leading to a greater deposition of bone mass and accelerating the process of bone consolidation. This work assessed the therapeutic effect of 780-nm laser PBM and a polystyrene membrane coated with norbixin and collagen (PSNC) on bone healing in rats with calvarial bone defect. Histological staining, Raman spectroscopy, and scanning electron microscopy (SEM) were used to evaluate the bone repair process. Four experimental treatment groups were compared: C, control; M, membrane only; L, laser PBM only; and ML, membrane + laser PBM. A bone defect was created in the calvaria of each animal, with each group subdivided into two subgroups that underwent euthanasia after 15 and 30 days treatment. The L and ML groups were irradiated (λ = 780 nm, ED = 6 J/cm 2 , P = 60 mW, t = 4 s) postoperatively on alternate days until they were euthanized. The bone concentration of hydroxyapatite (CHA) showed a clear gradation with increasing phosphate area in the order B (normal cortical bone) > L > M > ML > C for both periods. The PSNC membrane was effective in reducing the inflammatory process and served as a scaffold for bone repair. The laser PBM also showed positive effects on the bone repair process with increased deposition and organization of the newly formed bone. However, laser PBM failed to improve the bioactive properties of the membrane scaffold.

Histomorphologic findings on human bone samples six months after bone augmentation of the maxillary sinus with Algipore.

PubMed

Schopper, C; Moser, D; Wanschitz, F; Watzinger, F; Lagogiannis, G; Spassova, E; Ewers, R

1999-01-01

Sinus grafting, a popular and standard treatment for maxillary atrophy, uses a variety of grafting materials. In this study, specimens obtained 6 months after sinus grafting with Algipore were evaluated under light microscopy and showed osseoformation, xenograft degradation, and bone ingrowth into particles. Osteoblastic cells were embedded in the intracorpuscular bone matrix, which indicated that xenograft particles are an osseoconductive scaffold and stimulate matrix deposition. Acute inflammatory responses after insertion of Algipore did not occur. Particles were degraded during physiologic bone remodeling, and newly formed bone gradually replaced resorbed biomaterial.

Use of early tactile stimulation in rehabilitation of digital nerve injuries.

PubMed

Cheng, A S

2000-01-01

Digital nerves are the most frequently injured peripheral nerve. To improve the recovery of functional sensibility of digital nerve injuries, a prospective randomized controlled study was conducted to see the effect of using early tactile stimulation in rehabilitation of digital nerve injuries. Two specific tactile stimulators were made and prescribed for patients with digital nerve-injury. Twenty-four participants with 32 digital nerve injuries received the prescribed tactile stimulators (experimental group), and another 25 participants with 33 digital nerve injuries received only routine conventional therapy (control group). A significant difference (p < .05) was seen in the experimental group, although there were some variations between the different classes of associated injuries, with least benefit observed in the combined nerve, tendon, and bone injury class. Use of early tactile stimulation as described in this study can be considered an effective way to improve both quality and quantity of recovery of functional sensibility in digital nerve injuries without combined nerve, tendon, and bone injuries.

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.

Rapidly growing Brtl/+ mouse model of osteogenesis imperfecta improves bone mass and strength with sclerostin antibody treatment.

PubMed

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.

Evaluating the effectiveness of gel formulation of irradiated seed lectin Cratylia mollis during bone repair in rats

PubMed Central

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

[Research advances of fluid bio-mechanics in bone].

PubMed

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.

Postmenopausal Osteoporosis: The Role of Immune System Cells

PubMed Central

Faienza, Maria Felicia; Ventura, Annamaria; Marzano, Flaviana; Cavallo, Luciano

2013-01-01

In the last years, new evidences of the relationship between immune system and bone have been accumulated both in animal models and in humans affected by bone disease, such as rheumatoid arthritis, bone metastasis, periodontitis, and osteoporosis. Osteoporosis is characterized by low bone mass and microarchitectural deterioration of bone tissue with a subsequent increase in bone fragility and susceptibility to fractures. The combined effects of estrogen deprivation and raising of FSH production occurring in menopause cause a marked stimulation of bone resorption and a rapid bone loss which is central for the onset of postmenopausal osteoporosis. This review focuses on the role of immune system in postmenopausal osteoporosis and on therapeutic strategies targeting osteoimmunology pathways. PMID:23762093

In Vitro Impact of Conditioned Medium From Demineralized Freeze-Dried Bone on Human Umbilical Endothelial Cells.

PubMed

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.

Sclerostin Antibody Improves Skeletal Parameters in a Brtl/+ Mouse Model of Osteogenesis Imperfecta†

PubMed Central

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

Bone Talk: Activated Osteoblasts Promote Lung Cancer Growth.

PubMed

Bružas, Emilis; Egeblad, Mikala

2018-03-01

Cancer cells can directly stimulate the generation and recruitment of tumor-supportive bone marrow-derived cells (BMDCs), including neutrophils, via secreted factors. A new study demonstrates that lung tumors also remotely activate bone-residing osteoblasts, which in turn promote neutrophil production. This is a multistep mechanism of establishing a supportive tumor microenvironment. Copyright © 2018 Elsevier Ltd. All rights reserved.

[Endogenous pyrogen formation by bone marrow cells].

PubMed

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.

Skeletal secretion of FGF-23 regulates phosphate and vitamin D metabolism

PubMed Central

Quarles, L. Darryl

2014-01-01

The discovery of fibroblast growth factor 23 (FGF-23) has expanded our understanding of phosphate and vitamin D homeostasis and provided new insights into the pathogenesis of hereditary hypophosphatemic and hyperphosphatemic disorders, as well as acquired disorders of phosphate metabolism, such as chronic kidney disease. FGF-23 is secreted by osteoblasts and osteocytes in bone and principally targets the kidney to regulate the reabsorption of phosphate, the production and catabolism of 1,25-dihydroxyvitamin D and the expression of α-Klotho, an anti-ageing hormone. Secreted FGF-23 plays a central role in complex endocrine networks involving local bone-derived factors that regulate mineralization of extracellular matrix and systemic hormones involved in mineral metabolism. Inactivating mutations of PHEX, DMP1 and ENPP1, which cause hereditary hypophosphatemic disorders and primary defects in bone mineralization, stimulate FGF23 gene transcription in osteoblasts and osteocytes, at least in part, through canonical and intracrine FGF receptor pathways. These FGF-23 regulatory pathways may enable systemic phosphate and vitamin D homeostasis to be coordinated with bone mineralization. FGF-23 also functions as a counter-regulatory hormone for 1,25-dihydroxyvitamin D in a bone–kidney endocrine loop. FGF-23, through regulation of additional genes in the kidney and extrarenal tissues, probably has broader physiological functions beyond regulation of mineral metabolism that account for the association between FGF-23 and increased mortality and morbidity in chronic kidney disease. PMID:22249518

[Effects of recombinant human alpha-2b and gamma interferons on bone marrow megakaryocyte progenitors (CFU-Meg) from patients with chronic myelocytic leukemia].

PubMed

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.

Mechanisms of Mechano-Transduction Within Osteoblasts

DTIC Science & Technology

2001-09-01

bone sialoprotein , and fibronectin) that are the ligands for these receptors. We propose that the expression of these proteins is regulated in...system(s) that are responsible for mediating osteopontin, bone sialoprotein and fibronectin gene expression in response to mechanical stimulation, will

Butyric acid stimulates bone sialoprotein gene transcription.

PubMed

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.

Experiment K-6-23. Effect of spaceflight on levels and function of immune cells

NASA Technical Reports Server (NTRS)

Mandel, A. D.; Sonnenfeld, G.; Berry, W.; Taylor, G.; Wellhausen, S. R.; Konstantinova, I.; Lesnyak, A.; Fuchs, B.

1990-01-01

Two different immunology experiments were performed on samples received from rats flown on Cosmos 1887. In the first experiment, rat bone marrow cells were examined in Moscow for their response to colony stimulating factor-M. In the second experiment, rat spleen and bone marrow cells were stained in Moscow with a variety of antibodies directed against cell surface antigenic markers. These cells were preserved and shipped to the United States where they were subjected to analysis on a flow cytometer. The results of the studies indicate that bone marrow cells from flown rats showed a decreased response to colony stimulating factor than did bone marrow cells from control rats. There was a higher percentage of spleen cells from flown rats staining positively for pan-T-cell, suppressor-T-cell and innate interleukin-2 receptor antigens than from control animals. In addition, a higher percentage of cells that appeared to be part of the myelogenous population of bone marrow cells from flown rats stained positively for surface immunoglobulin than did equivalent cells from control rats.

Human stem cell osteoblastogenesis mediated by novel glycogen synthase kinase 3 inhibitors induces bone formation and a unique bone turnover biomarker profile in rats

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

Neuronal hypothalamic regulation of body metabolism and bone density is galanin dependent.

PubMed

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.

"Ruffled border" formation on a CaP-free substrate: A first step towards osteoclast-recruiting bone-grafts materials able to re-establish bone turn-over.

PubMed

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.

Acute bone response to whole body vibration in healthy pre-pubertal boys

PubMed Central

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

Acute bone response to whole body vibration in healthy pre-pubertal boys.

PubMed

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.

Mechanical stimulation promote the osteogenic differentiation of bone marrow stromal cells through epigenetic regulation of Sonic Hedgehog.

PubMed

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.

Effects of the incorporation of ε-aminocaproic acid/chitosan particles to fibrin on cementoblast differentiation and cementum regeneration.

PubMed

Park, Chan Ho; Oh, Joung-Hwan; Jung, Hong-Moon; Choi, Yoonnyoung; Rahman, Saeed Ur; Kim, Sungtae; Kim, Tae-Il; Shin, Hong-In; Lee, Yun-Sil; Yu, Frank H; Baek, Jeong-Hwa; Ryoo, Hyun-Mo; Woo, Kyung Mi

2017-10-01

Cementum formation on the exposed tooth-root surface is a critical process in periodontal regeneration. Although various therapeutic approaches have been developed, regeneration of integrated and functional periodontal complexes is still wanting. Here, we found that the OCCM30 cementoblasts cultured on fibrin matrix express substantial levels of matrix proteinases, leading to the degradation of fibrin and the apoptosis of OCCM30 cells, which was reversed upon treatment with a proteinase inhibitor, ε-aminocaproic acid (ACA). Based on these findings, ACA-releasing chitosan particles (ACP) were fabricated and ACP-incorporated fibrin (fibrin-ACP) promoted the differentiation of cementoblasts in vitro, as confirmed by bio-mineralization and expressions of molecules associated with mineralization. In a periodontal defect model of beagle dogs, fibrin-ACP resulted in substantial cementum formation on the exposed root dentin in vivo, compared to fibrin-only and enamel matrix derivative (EMD) which is used clinically for periodontal regeneration. Remarkably, the fibrin-ACP developed structural integrations of the cementum-periodontal ligament-bone complex by the Sharpey's fiber insertion. In addition, fibrin-ACP promoted alveolar bone regeneration through increased bone volume of tooth roof-of-furcation defects and root coverage. Therefore, fibrin-ACP can promote cementogenesis and osteogenesis by controlling biodegradability of fibrin, implicating the feasibility of its therapeutic use to improve periodontal regeneration. Cementum, the mineralized layer on root dentin surfaces, functions to anchor fibrous connective tissues on tooth-root surfaces with the collagenous Sharpey's fibers integration, of which are essential for periodontal functioning restoration in the complex. Through the cementum-responsible fiber insertions on tooth-root surfaces, PDLs transmit various mechanical responses to periodontal complexes against masticatory/occlusal stimulations to support teeth. In this study, periodontal tissue regeneration was enhanced by use of modified fibrin biomaterial which significantly promoted cementogenesis within the periodontal complex with structural integration by collagenous Sharpey's fiber insertions in vivo by controlling fibrin degradation and consequent cementoblast apoptosis. Furthermore, the modified fibrin could improve repair and regeneration of tooth roof-of-furcation defects, which has spatial curvatures and geometrical difficulties and hardly regenerates periodontal tissues. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Otoconial complexes as ion reservoirs in endolymph

NASA Technical Reports Server (NTRS)

Ross, M. D.; Williams, T. J.

1982-01-01

Scintillation spectrometry was employed to examine the Ca-45(2+) uptake and exchange by otoconial complexes in the sensory region endolymph medium, and a comparison was made with bone mineral deposition. CaCl was injected intraperitoneally into 222 rats and blood samples were collected at set intervals during the subsequent 15 min-l mo life durations of the animals. The animals were eventually sacrificed and saccular and utricular otoconial complexes were microdissected while bone chips from the otic bone and femur were gathered by scraping. Ca-45 was present in the saccular otoconial complexes within 15 min of injection, an uptake similar to the bone deposition, while slower rates were observed with the utricular complexes. Utricular uptake, however, accelerated 5-6 hr postinjection, and total otoconial content was always lower than proportional bone absorption.

Unrepaired DNA damage in macrophages causes elevation of particulate matter- induced airway inflammatory response.

PubMed

Luo, Man; Bao, Zhengqiang; Xu, Feng; Wang, Xiaohui; Li, Fei; Li, Wen; Chen, Zhihua; Ying, Songmin; Shen, Huahao

2018-04-14

The inflammatory cascade can be initiated with the recognition of damaged DNA. Macrophages play an essential role in particulate matter (PM)-induced airway inflammation. In this study, we aim to explore the PM induced DNA damage response of macrophages and its function in airway inflammation. The DNA damage response and inflammatory response were assessed using bone marrow-derived macrophages following PM treatment and mouse model instilled intratracheally with PM. We found that PM induced significant DNA damage both in vitro and in vivo and simultaneously triggered a rapid DNA damage response, represented by nuclear RPA, 53BP1 and γH2AX foci formation. Genetic ablation or chemical inhibition of the DNA damage response sensor amplified the production of cytokines including Cxcl1, Cxcl2 and Ifn-γ after PM stimulation in bone marrow-derived macrophages. Similar to that seen in vitro , mice with myeloid-specific deletion of RAD50 showed higher levels of airway inflammation in response to the PM challenge, suggesting a protective role of DNA damage sensor during inflammation. These data demonstrate that PM exposure induces DNA damage and activation of DNA damage response sensor MRN complex in macrophages. Disruption of MRN complex lead to persistent, unrepaired DNA damage that causes elevated inflammatory response.

Organ-on-a-chip: development and clinical prospects toward toxicity assessment with an emphasis on bone marrow.

PubMed

Kim, Jeehye; Lee, Hanna; Selimović, Šeila; Gauvin, Robert; Bae, Hojae

2015-05-01

Conventional approaches for toxicity evaluation of drugs and chemicals, such as animal tests, can be impractical due to the large experimental scale and the immunological differences between species. Organ-on-a-chip models have recently been recognized as a prominent alternative to conventional toxicity tests aiming to simulate the human in vivo physiology. This review focuses on the organ-on-a-chip applications for high-throughput screening of candidate drugs against toxicity, with a particular emphasis on bone-marrow-on-a-chip. Studies in which organ-on-a-chip models have been developed and utilized to maximize the efficiency and predictability in toxicity assessment are introduced. The potential of these devices to replace tests of acute systemic toxicity in animals, and the challenges that are inherent in simulating the human immune system are also discussed. As a promising approach to overcome the limitations, we further focus on an in-depth analysis of the development of bone-marrow-on-a-chip that is capable of simulating human immune responses against external stimuli due to the key roles of marrow in immune systems with hematopoietic activities. Owing to the complex interactions between hematopoietic stem cells and marrow microenvironments, precise control of both biochemical and physical niches that are critical in maintenance of hematopoiesis remains a key challenge. Thus, recently developed bone-marrow-on-a-chip models support immunogenicity and immunotoxicity testing in long-term cultivation with repeated antigen stimulation. In this review, we provide an overview of clinical studies that have been carried out on bone marrow transplants in patients with immune-related diseases and future aspects of clinical and pharmaceutical application of bone-marrow-on-a-chip.

Immortalization and characterization of osteoblast cell lines generated from wild-type and Nmp4-null mouse bone marrow stromal cells using murine telomerase reverse transcriptase (mTERT).

PubMed

Alvarez, Marta B; Childress, Paul; Philip, Binu K; Gerard-O'Riley, Rita; Hanlon, Michael; Herbert, Brittney-Shea; Robling, Alexander G; Pavalko, Fredrick M; Bidwell, Joseph P

2012-05-01

Intermittent parathyroid hormone (PTH) adds new bone to the osteoporotic skeleton; the transcription factor Nmp4/CIZ represses PTH-induced bone formation in mice and as a consequence is a potential drug target for improving hormone clinical efficacy. To explore the impact of Nmp4/CIZ on osteoblast phenotype, we immortalized bone marrow stromal cells from wildtype (WT) and Nmp4-knockout (KO) mice using murine telomerase reverse transcriptase. Clonal lines were initially chosen based on their positive staining for alkaline phosphatase and capacity for mineralization. Disabling Nmp4/CIZ had no gross impact on osteoblast phenotype development. WT and KO clones exhibited identical sustained growth, reduced population doubling times, extended maintenance of the mature osteoblast phenotype, and competency for differentiating toward the osteoblast and adipocyte lineages. Additional screening of the immortalized cells for PTH-responsiveness permitted further studies with single WT and KO clones. We recently demonstrated that PTH-induced c-fos femoral mRNA expression is enhanced in Nmp4-KO mice and in the present study we observed that hormone stimulated either an equivalent or modestly enhanced increase in c-fos mRNA expression in both primary null and KO clone cells depending on PTH concentration. The null primary osteoblasts and KO clone cells exhibited a transiently enhanced response to bone morphogenetic protein 2 (BMP2). The clones exhibited lower and higher expressions of the PTH receptor (Pthr1) and the BMP2 receptor (Bmpr1a, Alk3), respectively, as compared to primary cells. These immortalized cell lines will provide a valuable tool for disentangling the complex functional roles underlying Nmp4/CIZ regulation of bone anabolism. Copyright © 2011 Wiley Periodicals, Inc.

Design of complex bone internal structure using topology optimization with perimeter control.

PubMed

Park, Jaejong; Sutradhar, Alok; Shah, Jami J; Paulino, Glaucio H

2018-03-01

Large facial bone loss usually requires patient-specific bone implants to restore the structural integrity and functionality that also affects the appearance of each patient. Titanium alloys (e.g., Ti-6Al-4V) are typically used in the interfacial porous coatings between the implant and the surrounding bone to promote stability. There exists a property mismatch between the two that in general leads to complications such as stress-shielding. This biomechanical discrepancy is a hurdle in the design of bone replacements. To alleviate the mismatch, the internal structure of the bone replacements should match that of the bone. Topology optimization has proven to be a good technique for designing bone replacements. However, the complex internal structure of the bone is difficult to mimic using conventional topology optimization methods without additional restrictions. In this work, the complex bone internal structure is recovered using a perimeter control based topology optimization approach. By restricting the solution space by means of the perimeter, the intricate design complexity of bones can be achieved. Three different bone regions with well-known physiological loadings are selected to illustrate the method. Additionally, we found that the target perimeter value and the pattern of the initial distribution play a vital role in obtaining the natural curvatures in the bone internal structures as well as avoiding excessive island patterns. Copyright © 2018 Elsevier Ltd. All rights reserved.

Bone and muscle: Interactions beyond mechanical.

PubMed

Brotto, Marco; Bonewald, Lynda

2015-11-01

The musculoskeletal system is significantly more complex than portrayed by traditional reductionist approaches that have focused on and studied the components of this system separately. While bone and skeletal muscle are the two largest tissues within this system, this system also includes tendons, ligaments, cartilage, joints and other connective tissues along with vascular and nervous tissues. Because the main function of this system is locomotion, the mechanical interaction among the major players of this system is essential for the many shapes and forms observed in vertebrates and even in invertebrates. Thus, it is logical that the mechanical coupling theories of musculoskeletal development exert a dominant influence on our understanding of the biology of the musculoskeletal system, because these relationships are relatively easy to observe, measure, and perturb. Certainly much less recognized is the molecular and biochemical interaction among the individual players of the musculoskeletal system. In this brief review article, we first introduce some of the key reasons why the mechanical coupling theory has dominated our view of bone-muscle interactions followed by summarizing evidence for the secretory nature of bones and muscles. Finally, a number of highly physiological questions that cannot be answered by the mechanical theories alone will be raised along with different lines of evidence that support both a genetic and a biochemical communication between bones and muscles. It is hoped that these discussions will stimulate new insights into this fertile and promising new way of defining the relationships between these closely related tissues. Understanding the cellular and molecular mechanisms responsible for biochemical communication between bone and muscle is important not only from a basic research perspective but also as a means to identify potential new therapies for bone and muscle diseases, especially for when they co-exist. This article is part of a Special Issue entitled "Muscle Bone Interactions". Copyright © 2015 Elsevier Inc. All rights reserved.

Mice lacking bone sialoprotein (BSP) lose bone after ovariectomy and display skeletal site-specific response to intermittent PTH treatment.

PubMed

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.

Synthesis of nitric oxide in human osteoblasts in response to physiologic stimulation of electrotherapy.

PubMed

Hamed, Ayman; Kim, Paul; Cho, Michael

2006-12-01

Electrotherapy for bone healing, remodeling and wound healing may be mediated by modulation of nitric oxide (NO). Using NO-specific fluorophore (DAF-2), we report here that application of non-invasive, physiologic electrical stimulation induces NO synthesis in human osteoblasts, and that such NO generation is comparable to that induced by estrogen treatment. For example, application of a sinusoidal 1 Hz, 2 V/cm (peak to peak) electrical stimulation (ES) increases NO-bound DAF-2 fluorescence intensity by a 2-fold within 60 min exposure by activating nitric oxide synthase (NOS). Increase in the NO level is found to depend critically on the frequency and strength of ES. While the frequency of 1 Hz ES seems optimal, the ES strength >0.5 V/cm is required to induce significant NO increase, however. Nitric oxide synthesis in response to ES is completely prevented by blocking estrogen receptors using a competitive inhibitor, suggesting that NO generation is likely initiated by activation of estrogen receptors at the cell surface. Based on these findings, physiologic stimulation of electrotherapy appears to represent a potential non-invasive, non-genomic, and novel physical technique that could be used to regulate NO-mediated bone density and facilitate bone remodeling without adverse effects associated with hormone therapy.

Effects of neuromuscular electrical stimulation combined with effortful swallowing on post-stroke oropharyngeal dysphagia: a randomised controlled trial.

PubMed

Park, J-S; Oh, D-H; Hwang, N-K; Lee, J-H

2016-06-01

Neuromuscular electrical stimulation (NMES) has been used as a therapeutic intervention for dysphagia. However, the therapeutic effects of NMES lack supporting evidence. In recent years, NMES combined with traditional swallowing therapy has been used to improve functional recovery in patients with post-stroke dysphagia. This study aimed to investigate the effects of effortful swallowing combined with neuromuscular electrical stimulation on hyoid bone movement and swallowing function in stroke patients. Fifty stroke patients with mild dysphagia who were able to swallow against the resistance applied by using NMES and cooperate actively in training were included. This study was designed as a 6-week single-blind, randomised, controlled study. In the experimental group, two pairs of electrodes were placed horizontally in the infrahyoid region to depress the hyoid bone. The NMES intensity was increased gradually until the participants felt a grabbing sensation in their neck and performed an effortful swallow during the stimulation. In the placebo group, the same procedure was followed except for the intensity, which was increased gradually until the participants felt an electrical sensation. All participants underwent this intervention for 30 min per session, 5 sessions per week, for 6 weeks. Videofluoroscopic swallowing studies (VFSS) were carried out before and after the intervention and kinematics of the hyoid bone and swallowing function were analysed based on the VFSS. The experimental group revealed a significant increase in anterior and superior hyoid bone movement and the pharyngeal phase of the swallowing function. This intervention can be used as a novel remedial approach in dysphagic stroke patients. © 2016 John Wiley & Sons Ltd.

Augmented cartilage regeneration by implantation of cellular versus acellular implants after bone marrow stimulation: a systematic review and meta-analysis of animal studies.

PubMed

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.

Missense Mutations in LRP5 Associated with High Bone Mass Protect the Mouse Skeleton from Disuse- and Ovariectomy-Induced Osteopenia.

PubMed

Niziolek, Paul J; Bullock, Whitney; Warman, Matthew L; Robling, Alexander G

2015-01-01

The low density lipoprotein receptor-related protein-5 (LRP5), a co-receptor in the Wnt signaling pathway, modulates bone mass in humans and in mice. Lrp5 knock-out mice have severely impaired responsiveness to mechanical stimulation whereas Lrp5 gain-of-function knock-in and transgenic mice have enhanced responsiveness to mechanical stimulation. Those observations highlight the importance of Lrp5 protein in bone cell mechanotransduction. It is unclear if and how high bone mass-causing (HBM) point mutations in Lrp5 alter the bone-wasting effects of mechanical disuse. To address this issue we explored the skeletal effects of mechanical disuse using two models, tail suspension and Botulinum toxin-induced muscle paralysis, in two different Lrp5 HBM knock-in mouse models. A separate experiment employing estrogen withdrawal-induced bone loss by ovariectomy was also conducted as a control. Both disuse stimuli induced significant bone loss in WT mice, but Lrp5 A214V and G171V were partially or fully protected from the bone loss that normally results from disuse. Trabecular bone parameters among HBM mice were significantly affected by disuse in both models, but these data are consistent with DEXA data showing a failure to continue growing in HBM mice, rather than a loss of pre-existing bone. Ovariectomy in Lrp5 HBM mice resulted in similar protection from catabolism as was observed for the disuse experiments. In conclusion, the Lrp5 HBM alleles offer significant protection from the resorptive effects of disuse and from estrogen withdrawal, and consequently, present a potential mechanism to mimic with pharmaceutical intervention to protect against various bone-wasting stimuli.

An experimental study on the application of radionuclide imaging in repair of the bone defect

PubMed Central

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

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.

Stimulation of globin synthesis: relative responsiveness of reticulocytes and nucleated erythroid cells

PubMed Central

Waxman, Herbert S.

1970-01-01

The effects of iron, cobalt, hemin, and plasma on hemoglobin synthesis by suspensions of rabbit reticulocytes and nucleated bone marrow cells were studied. L-Leucine-14C and sodium pyruvate-3-14C were employed to measure globin and heme synthesis, respectively. Normal plasma (or serum) was found to stimulate the rate of globin synthesis in both systems. The stimulatory effects of iron and hemin were additive to those of plasma or serum only in the reticulocytes. Cobaltous ion, at concentrations less than 1.0 mmole/liter, was found to stimulate globin synthesis by reticulocytes as effectively as ferrous ion; cobalt was inhibitory only at concentrations greater than 3.0-5.0 mmoles/liter. Heme synthesis by reticulocytes was inhibited at all concentrations employed (0.2-5.0 mmoles/liter). In bone marrow nucleated erythroid cells, globin synthesis was markedly enhanced by exogenous hemin. In contrast to reticulocytes, however, bone marrow cells were unresponsive to either cobalt or transferrin-bound iron. Possible implications of these findings on regulation of the rate and mechanism of iron uptake and hemoglobin synthesis in vivo are discussed. PMID:5443172

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yusa, Kazuyuki; Yamamoto, Osamu; Fukuda, Masayuki

Highlights: {yields} We isolated the Zn{sup 2+} ions (eluted Zn{sup 2+} ion; EZ) from zinc-incorporated titanium implant. {yields} The EZ promoted the cell viability in hBMCs. {yields} The EZ stimulated preosteoblast and osteoblast marker gene expression in hBMCs. {yields} The hBMCs supplemented with EZ showed typically cell morphology when osteoblast maturing. {yields} It is revealed that the EZ also stimulates the calcium deposition of hBMCs. -- Abstract: Zinc is one of the trace elements which induce the proliferation and the differentiation of the osteoblast. In the previous study, we found that zinc ions (Zn{sup 2+} ion)-releasing titanium implants had excellentmore » bone fixation using a rabbit femurs model. In this study, we isolated the Zn{sup 2+} ions (eluted Zn{sup 2+} ion; EZ) released from the implant surface, and evaluated the effect of EZ on the osteogenesis of human bone marrow-derived mesenchymal cells (hBMCs). In the result, it was found that the EZ stimulated cell viability, osteoblast marker gene (type I collagen, osteocalcin (OC), alkaline phosphatase (ALP) and bone sialoprotein (BSP)) expressions and calcium deposition in hBMCs.« less

Digital electronic bone growth stimulator

DOEpatents

Kronberg, J.W.

1993-01-01

The present invention relates to the electrical treatment of biological tissue. In particular, the present invention discloses a device that produces discrete electrical pulse trains for treating osteoporosis and accelerating bone growth. According to its major aspects and broadly stated, the present invention consists of an electrical circuit configuration capable of generating Bassett-type waveforms shown with alternative signals provide for the treatment of either fractured bones or osteoporosis. The signal generator comprises a quartz clock, an oscillator circuit, a binary divider chain, and a plurality of simple, digital logic gates. Signals are delivered efficiently, with little or no distortion, and uniformly distributed throughout the area of injury. Perferably, power is furnished by widely available and inexpensive radio batteries, needing replacement only once in several days. The present invention can be affixed to a medical cast without a great increase in either weight or bulk. Also, the disclosed stimulator can be used to treat osteoporosis or to strengthen a healing bone after the cast has been removed by attaching the device to the patient`s skin or clothing.

Muscle and bone plasticity after spinal cord injury: Review of adaptations to disuse and to electrical muscle stimulation

PubMed Central

Dudley-Javoroski, Shauna; Shields, Richard K.

2009-01-01

The paralyzed musculoskeletal system retains a remarkable degree of plasticity after spinal cord injury (SCI). In response to reduced activity, muscle atrophies and shifts toward a fast-fatigable phenotype arising from numerous changes in histochemistry and metabolic enzymes. The loss of routine gravitational and muscular loads removes a critical stimulus for maintenance of bone mineral density (BMD), precipitating neurogenic osteoporosis in paralyzed limbs. The primary adaptations of bone to reduced use are demineralization of epiphyses and thinning of the diaphyseal cortical wall. Electrical stimulation of paralyzed muscle markedly reduces deleterious post-SCI adaptations. Recent studies demonstrate that physiological levels of electrically induced muscular loading hold promise for preventing post-SCI BMD decline. Rehabilitation specialists will be challenged to develop strategies to prevent or reverse musculoskeletal deterioration in anticipation of a future cure for SCI. Quantifying the precise dose of stress needed to efficiently induce a therapeutic effect on bone will be paramount to the advancement of rehabilitation strategies. PMID:18566946

In vitro bioactivity of akermanite ceramics.

PubMed

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

Abnormal XPD-induced nuclear receptor transactivation in DNA repair disorders: trichothiodystrophy and xeroderma pigmentosum.

PubMed

Zhou, Xiaolong; Khan, Sikandar G; Tamura, Deborah; Ueda, Takahiro; Boyle, Jennifer; Compe, Emmanuel; Egly, Jean-Marc; DiGiovanna, John J; Kraemer, Kenneth H

2013-08-01

XPD (ERCC2) is a DNA helicase involved in nucleotide excision repair and in transcription as a structural bridge tying the transcription factor IIH (TFIIH) core with the cdk-activating kinase complex, which phosphorylates nuclear receptors. Mutations in XPD are associated with several different phenotypes, including trichothiodystrophy (TTD), with sulfur-deficient brittle hair, bone defects, and developmental abnormalities without skin cancer, xeroderma pigmentosum (XP), with pigmentary abnormalities and increased skin cancer, or XP/TTD with combined features, including skin cancer. We describe the varied clinical features and mutations in nine patients examined at the National Institutes of Health who were compound heterozygotes for XPD mutations but had different clinical phenotypes: four TTD, three XP, and two combined XP/TTD. We studied TFIIH-dependent transactivation by nuclear receptor for vitamin D (VDR) and thyroid in cells from these patients. The vitamin D stimulation ratio of CYP24 and osteopontin was associated with specific pairs of mutations (reduced in 5, elevated in 1) but not correlated with distinct clinical phenotypes. Thyroid receptor stimulation ratio for KLF9 was not significantly different from normal. XPD mutations frequently were associated with abnormal VDR stimulation in compound heterozygote patients with TTD, XP, or XP/TTD.

Pomegranate Peel Extract Prevents Bone Loss in a Preclinical Model of Osteoporosis and Stimulates Osteoblastic Differentiation in Vitro.

PubMed

Spilmont, Mélanie; Léotoing, Laurent; Davicco, Marie-Jeanne; Lebecque, Patrice; Miot-Noirault, Elisabeth; Pilet, Paul; Rios, Laurent; Wittrant, Yohann; Coxam, Véronique

2015-11-11

The nutritional benefits of pomegranate have attracted great scientific interest. The pomegranate, including the pomegranate peel, has been used worldwide for many years as a fruit with medicinal activity, mostly antioxidant properties. Among chronic diseases, osteoporosis, which is associated with bone remodelling impairment leading to progressive bone loss, could eventually benefit from antioxidant compounds because of the involvement of oxidative stress in the pathogenesis of osteopenia. In this study, with in vivo and ex vivo experiments, we investigated whether the consumption of pomegranate peel extract (PGPE) could limit the process of osteopenia. We demonstrated that in ovariectomized (OVX) C57BL/6J mice, PGPE consumption was able to significantly prevent the decrease in bone mineral density (-31.9%; p < 0.001 vs. OVX mice) and bone microarchitecture impairment. Moreover, the exposure of RAW264.7 cells to serum harvested from mice that had been given a PGPE-enriched diet elicited reduced osteoclast differentiation and bone resorption, as shown by the inhibition of the major osteoclast markers. In addition, PGPE appeared to substantially stimulate osteoblastic MC3T3-E1 alkaline phosphatase (ALP) activity at day 7, mineralization at day 21 and the transcription level of osteogenic markers. PGPE may be effective in preventing the bone loss associated with ovariectomy in mice, and offers a promising alternative for the nutritional management of this disease.

Pomegranate Peel Extract Prevents Bone Loss in a Preclinical Model of Osteoporosis and Stimulates Osteoblastic Differentiation in Vitro

PubMed Central

Spilmont, Mélanie; Léotoing, Laurent; Davicco, Marie-Jeanne; Lebecque, Patrice; Miot-Noirault, Elisabeth; Pilet, Paul; Rios, Laurent; Wittrant, Yohann; Coxam, Véronique

2015-01-01

The nutritional benefits of pomegranate have attracted great scientific interest. The pomegranate, including the pomegranate peel, has been used worldwide for many years as a fruit with medicinal activity, mostly antioxidant properties. Among chronic diseases, osteoporosis, which is associated with bone remodelling impairment leading to progressive bone loss, could eventually benefit from antioxidant compounds because of the involvement of oxidative stress in the pathogenesis of osteopenia. In this study, with in vivo and ex vivo experiments, we investigated whether the consumption of pomegranate peel extract (PGPE) could limit the process of osteopenia. We demonstrated that in ovariectomized (OVX) C57BL/6J mice, PGPE consumption was able to significantly prevent the decrease in bone mineral density (−31.9%; p < 0.001 vs. OVX mice) and bone microarchitecture impairment. Moreover, the exposure of RAW264.7 cells to serum harvested from mice that had been given a PGPE-enriched diet elicited reduced osteoclast differentiation and bone resorption, as shown by the inhibition of the major osteoclast markers. In addition, PGPE appeared to substantially stimulate osteoblastic MC3T3-E1 alkaline phosphatase (ALP) activity at day 7, mineralization at day 21 and the transcription level of osteogenic markers. PGPE may be effective in preventing the bone loss associated with ovariectomy in mice, and offers a promising alternative for the nutritional management of this disease. PMID:26569295

Three-dimensional plotted alginate fibers embedded with diclofenac and bone cells coated with chitosan for bone regeneration during inflammation.

PubMed

Lin, Hsin-Yi; Chang, Tsang-Wen; Peng, Tie-Kun

2018-06-01

Alginate hydrogel fibers embedded with bone cells and diclofenac were coated with a layer of chitosan hydrogel and made into a porous scaffold by three-dimensional (3D) printing for drug release and bone regeneration. It was hypothesized that the chitosan coating could improve the scaffold's drug retention and release properties and biocompatibility. Macrophage cells were stimulated and cocultured with the scaffold. Tests were conducted to show how the chitosan coating affected the scaffold's drug release efficacy and how the release efficacy affected the cellular activities of stimulated macrophages and bone cells. The bone cells encapsulated in the coated scaffold demonstrated good viability after the acidic/basic coating process. The coating improved the retention and release efficacy of diclofenac and hence significantly inhibited interleukin-6 and tumor necrosis factor-α secretion from macrophages (p < 0.05). The bone cells in the coated sample mineralized more extensively than the control (p < 0.01). They also more actively expressed genes that produce proteins for extracellular matrix remodeling, MMP13, and interacting with the mineral matrix, OPN (both p < 0.01). It is believed that on days 7 and 10, when diclofenac was depleted and the concentrations of inflammatory compounds surged, the coating effectively blocked the harmful compounds and protected the bone cells within the fibers. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1511-1521, 2018. © 2018 Wiley Periodicals, Inc.

Desferrioxamine for Stimulation of Fracture Healing and Revascularization in a Bone Defect Model

DTIC Science & Technology

2012-02-01

cartilaginous tissue still present. DBM + L-DFO: Fracture gap less evident with more complete bone bridging with denser trabecular bone and less...fracture callus volume by micro-CT, and qualitative histology for callus tissue quality and vascularity in 5 groups (No implant, CS implant, DFO+CS...Weinhold, P. North Carolina Tissue Engineering and Regenerative Medicine Meeting, November 4, 2011; Winston Salem, NC. (presented) • Desferroxamine with

In vitro electromagnetically stimulated SAOS-2 osteoblasts inside porous hydroxyapatite

PubMed Central

Fassina, Lorenzo; Saino, Enrica; Sbarra, Maria Sonia; Visai, Livia; De Angelis, Maria Gabriella Cusella; Magenes, Giovanni; Benazzo, Francesco

2009-01-01

One of the key challenges in reconstructive bone surgery is to provide living constructs that possess the ability to integrate in the surrounding tissue. Bone graft substitutes, such as autografts, allografts, xenografts, and biomaterials have been widely used to heal critical-size long bone defects due to trauma, tumor resection, congenital deformity, and tissue degeneration. In particular, porous hydroxyapatite is widely used in reconstructive bone surgery owing to its biocompatibility. In addition, the in vitro modification of hydroxyapatite with osteogenic signals enhances the tissue regeneration in vivo, suggesting that the biomaterial modification could play an important role in tissue engineering. In this study we have followed a biomimetic strategy where electromagnetically stimulated SAOS-2 human osteoblasts proliferated and built their extracellular matrix inside a porous hydroxyapatite scaffold. The electromagnetic stimulus had the following parameters: intensity of the magnetic field equal to 2 mT, amplitude of the induced electric tension equal to 5 mV, frequency of 75 Hz, and pulse duration of 1.3 ms. In comparison with control conditions, the electromagnetic stimulus increased the cell proliferation and the surface coating with bone proteins (decorin, osteocalcin, osteopontin, type-I collagen, and type-III collagen). The physical stimulus aimed at obtaining a better modification of the biomaterial internal surface in terms of cell colonization and coating with bone matrix. PMID:19827111

Enhancement of bone consolidation in mandibular distraction osteogenesis: a contemporary review of experimental studies involving adjuvant therapies.

PubMed

Hong, Paul; Boyd, Daniel; Beyea, Steven D; Bezuhly, Michael

2013-07-01

One of the major disadvantages of mandibular distraction osteogenesis (MDO) is the prolonged time required for consolidation of the regenerate bone. The objective of the present study is to perform a contemporary review of various adjuvant therapies to enhance bone consolidation in MDO. A PubMed search for articles related to MDO, along with the references of those articles, was performed. Inclusion and exclusion criteria were applied to all experimental studies assessing adjuvant therapies to enhance bone consolidation. A total of 1414 titles and abstracts were initially reviewed; 61 studies were included for full review. Many studies involved growth factors, hormones, pharmacological agents, gene therapy, and stem cells. Other adjuvant therapies included mechanical stimulation, laser therapy, and hyperbaric oxygen. Majority of the studies demonstrated positive bone healing effects and thus adjuvant therapies remain a viable strategy to enhance and hasten the consolidation period. Although most studies have demonstrated promising results, many questions still remain, such as optimal amount, timing, and delivery methods required to stimulate the most favorable bone regeneration. As well, further studies comparing various adjuvant therapies and documentation of long-term adverse effects are required prior to clinical application. Copyright © 2013 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Carbon nanotubes with high bone-tissue compatibility and bone-formation acceleration effects.

PubMed

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.

Suppression of autophagy in osteocytes does not modify the adverse effects of glucocorticoids on cortical bone.

PubMed

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.

Suppression of Autophagy in Osteocytes Does Not Modify the Adverse Effects of Glucocorticoids on Cortical Bone

PubMed Central

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

Peripheral cannabinoid receptor, CB2, regulates bone mass

PubMed Central

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

The role of pain catastrophizing in experimental pain perception.

PubMed

Kristiansen, Frederik L; Olesen, Anne E; Brock, Christina; Gazerani, Parisa; Petrini, Laura; Mogil, Jeffrey S; Drewes, Asbjørn M

2014-03-01

Pain is a subjective experience influenced by multiple factors, and tremendous variety within individuals is present. To evaluate emotional state of pain, catastrophizing score can be used. This study investigated pain catastrophizing ratings in association with experimental pain perception. Experimental pain was induced using thermal heat and cold stimulation of skin, mechanical stimulation of muscle and bone, and thermal, mechanical, and electrical stimulation of the gastrointestinal tract in healthy participants (N = 41). Prior to experimental sessions, a pain catastrophizing questionnaire was filled out by each participant. Based on the median catastophizing score, participants were divided into two groups: noncatastrophizers and low-catastrophizers. No significant difference was found between low-catastrophizers and noncatastrophizers in thermal heat stimulation of skin, mechanical stimulation of muscle and bone, and rectal electrical stimulation (All P > 0.05). Low-catastrophizers were more sensitive to visceral thermal stimulation (4.7%, P = 0.02) and visceral mechanical stimulation (29.7%, P = 0.03). For participants that completed the 120 seconds ice water stimulation, noncatastrophizers reported 13.8% less pain than low-catastrophizers (P = 0.02). A positive correlation between PCS score and pain perception on cold pressor test was found (r = 0.4, P = 0.02). By extrapolating data, further analysis of the total group was performed and no differences (both P > 0.05) were observed. Even small increments in pain catastrophizing score can influence pain perception to deep and tonic stimulations. Catatrophizing may partly explain the variability found in experimental pain studies. © 2013 World Institute of Pain.

Centrifugation of Cultured Osteoblasts And Macrophages as a Model To Study How Gravity Regulates The Function of Skeletal Cells

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.

Age-related differences in hormonal and nutritional impact on lean anorexia nervosa bone turnover uncoupling.

PubMed

Galusca, B; Bossu, C; Germain, N; Kadem, M; Frere, D; Lafage-Proust, M H; Lang, F; Estour, B

2006-01-01

In anorexia nervosa (AN) patients osteoporosis occurs within a framework of multiple hormonal abnormalities as a result of bone turnover uncoupling, with decreased bone formation and increased bone resorption. The aim of study was to evaluate the hormonal and nutritional relationships with both of these bone remodeling compartments and their eventual modifications with age. In a cohort of 115 AN patients (mean BMI:14.6 kg/m2) that included 60 mature adolescents (age: 15.5-20 years) and 55 adult women (age: 20-37 years) and in 28 age-matched controls (12 mature adolescents and 16 adults) we assessed: bone markers [serum osteocalcin, skeletal alkaline phosphatase (sALP), C-telopeptide of type I collagen (sCTX) and tartrate-resistant acid phosphatase type 5b (TRAP 5b)], nutritional markers [ body mass index (BMI, fat and lean mass), hormones (free tri-iodothyronine (T3), free T4, thyroid stimulating hormone (TSH), luteinizing hormone (LH), follicle stimulating hormone (FSH), 17 beta estradiol, free testosterone index (FTI), dehydroepiandrosterone (DHEAS), insulin-like growth factor 1 (IGF-1), growth hormone (GH) and cortisol], plasma methoxyamines (metanephrine and normetanephrine) and calcium metabolism parameters [parathyroid hormone (PTH), Ca, vitamin D3]. Osteocalcin reached similar low levels in both AN age subgroups. sCTX levels were found to be elevated in all AN subjects and higher in mature adolescents than in adult AN (11,567+/-895 vs. 8976+/-805 pmol/l, p<0.05). sALP was significantly lower only in mature adolescent AN patients, while there were no significant differences in the levels of TRAP 5b between AN patients and age-matched control groups. Osteocalcin correlated with sCTX in the control subjects (r=0.65) but not in the AN patients, suggesting the independent regulation of these markers in AN patients. Osteocalcin levels strongly correlated with freeT3, IGF-I, 17 beta estradiol and cortisol, while sCTX correlated with IGF-I, GH and cortisol in both age subgroups of the AN patients. Other hormones or nutritional parameters displayed age-related correlations with bone markers, leading to different stepwise regression models for each age interval. In mature adolescent AN patients, up to 54% of the osteocalcin variance was due to BMI, cortisol and 17 beta estradiol, while 54% of the sCTX variance was determined by GH. In adult subjects, freeT3 and IGF-I accounted for 64% of osteocalcin variance, while 65% of the sCTX variance was due to GH, FTI and methoxyamines. We suggest a more complex mechanism of AN bone uncoupling that includes not only "classical" influence elements like cortisol, IGF-I, GH or 17 beta estradiol but also freeT3, catecholamines and a "direct" hormone-independent impact of denutrition. Continuous changes of these influences with age should be considered within the therapeutic approach to AN bone loss.

Feasibility study of Transcutaneous Electrical Nerve Stimulation (TENS) for cancer bone pain.

PubMed

Bennett, Michael I; Johnson, Mark I; Brown, Sarah R; Radford, Helen; Brown, Julia M; Searle, Robert D

2010-04-01

This multicenter study assessed the feasibility of conducting a phase III trial of transcutaneous electrical nerve stimulation (TENS) in patients with cancer bone pain recruited from palliative care services. Eligible patients received active and placebo TENS for 1 hour at site of pain in a randomized crossover design; median interval between applications 3 days. Responses assessed at 30 and 60 minutes included numerical and verbal ratings of pain at rest and on movement, and pain relief. Recruitment, tolerability, adverse events, and effectiveness of blinding were also evaluated. Twenty-four patients were randomised and 19 completed both applications. The intervention was well tolerated. Five patients withdrew: 3 due to deteriorating performance status, and 2 due to increased pain (1 each following active and placebo TENS). Confidence interval estimation around the differences in outcomes between active and placebo TENS suggests that TENS has the potential to decrease pain on movement more than pain on rest. Nine patients did not consider that a placebo was used; the remaining 10 correctly identified placebo TENS. Feasibility studies are important in palliative care prior to undertaking clinical trials. Our findings suggest that further work is required on recruitment strategies and refining the control arm before evaluating TENS in cancer bone pain. Cancer bone pain is common and severe, and partly mediated by hyperexcitability. Animal studies suggest that Transcutaneous Electrical Nerve Stimulation can reduce hyperalgesia. This study examined the feasibility of evaluating TENS in patients with cancer bone pain in order to optimize methods before a phase III trial. Copyright 2010 American Pain Society. Published by Elsevier Inc. All rights reserved.

Resveratrol Increases Osteoblast Differentiation In Vitro Independently of Inflammation.

PubMed

Ornstrup, Marie Juul; Harsløf, Torben; Sørensen, Lotte; Stenkjær, Liselotte; Langdahl, Bente Lomholt; Pedersen, Steen Bønløkke

2016-08-01

Low-grade inflammation negatively affects bone. Resveratrol is a natural compound proven to possess both anti-inflammatory and bone protective properties. However, it is uncertain if the bone effects are mediated though anti-inflammatory effects. Firstly, we investigated if resveratrol affects proliferation and differentiation of human bone marrow-derived mesenchymal stem cells. Secondly, we investigated if inflammation negatively affects proliferation and differentiation, and if resveratrol counteracts this through anti-inflammatory effects. Mesenchymal stem cells were obtained from bone marrow aspiration in 13 healthy individuals and cultured towards the osteoblast cell lineage. The cells were stimulated with resveratrol, lipopolysaccharide (LPS), LPS + resveratrol, or vehicle (control) for 21 days. Compared to control, resveratrol decreased cell number by 35 % (p < 0.05) and induced differentiation (a 3-fold increase in alkaline phosphatase (p < 0.002), while P1NP and OPG showed similar trends). LPS induced inflammation with a 44-fold increase in interleukin-6 (p < 0.05) and an extremely prominent increase in interleukin-8 production (p < 0.05) relative to control. In addition, LPS increased cell count (p < 0.05) and decreased differentiation (a reduction in P1NP production (p < 0.02)). Co-stimulation with LPS + resveratrol did not reduce interleukin-6 or interleukin-8, but nonetheless, cell count was reduced (p < 0.05) and alkaline phosphatase, P1NP, and OPG increased (p < 0.05 for all). Thus, resveratrol stimulates osteoblast differentiation independently of inflammation.

Comparison of transplantation of bone marrow stromal cells (BMSC) and stem cell mobilization by granulocyte colony stimulating factor after traumatic brain injury in rat.

PubMed

Bakhtiary, Mehrdad; Marzban, Mohsen; Mehdizadeh, Mehdi; Joghataei, Mohammad Taghi; Khoei, Samideh; Pirhajati Mahabadi, Vahid; Laribi, Bahareh; Tondar, Mahdi; Moshkforoush, Arash

2010-10-01

Recent clinical studies of treating traumatic brain injury (TBI) with autologous adult stem cells led us to compare effect of intravenous injection of bone marrow mesenchymal stem cells (BMSC) and bone marrow hematopoietic stem cell mobilization, induced by granulocyte colony stimulating factor (G-CSF), in rats with a cortical compact device. Forty adult male Wistar rats were injured with controlled cortical impact device and divided randomly into four groups. The treatment groups were injected with 2 × 106 intravenous bone marrow stromal stem cell (n = 10) and also with subcutaneous G-CSF (n = 10) and sham-operation group (n = 10) received PBS and "bromodeoxyuridine (Brdu)" alone, i.p. All injections were performed 1 day after injury into the tail veins of rats. All cells were labeled with Brdu before injection into the tail veins of rats. Functional neurological evaluation of animals was performed before and after injury using modified neurological severity scores (mNSS). Animals were sacrificed 42 days after TBI and brain sections were stained by Brdu immunohistochemistry. Statistically, significant improvement in functional outcome was observed in treatment groups compared with control group (P<0.01). mNSS showed no significant difference between the BMSC and G-CSF-treated groups during the study period (end of the trial). Histological analyses showed that Brdu-labeled (MSC) were present in the lesion boundary zone at 42nd day in all injected animals. In our study, we found that administration of a bone marrow-stimulating factor (G-CSF) and BMSC in a TBI model provides functional benefits.

TRIENNIAL LACTATION SYMPOSIUM/BOLFA: Serotonin and the regulation of calcium transport in dairy cows.

PubMed

Hernandez, L L

2017-12-01

The mammary gland regulates maternal metabolism during lactation. Numerous factors within the tissue send signals to shift nutrients to the mammary gland for milk synthesis. Serotonin is a monoamine that has been well documented to regulate several aspects of lactation among species. Maintenance of maternal calcium homeostasis during lactation is a highly evolved process that is elegantly regulated by the interaction of the mammary gland with the bone, gut, and kidney tissues. It is well documented that dietary calcium is insufficient to maintain maternal calcium concentrations during lactation, and mammals must rely on bone resorption to maintain normocalcemia. Our recent work focused on the ability of the mammary gland to function as an accessory parathyroid gland during lactation. It was demonstrated that serotonin acts to stimulate parathyroid hormone-related protein (PTHrP) in the mammary gland during lactation. The main role of mammary-derived PTHrP during mammalian lactation is to stimulate bone resorption to maintain maternal calcium homeostasis during lactation. In addition to regulating PTHrP, it was shown that serotonin appears to directly affect calcium transporters and pumps in the mammary gland. Our current working hypothesis regarding the control of calcium during lactation is as follows: serotonin directly stimulates PTHrP production in the mammary gland through interaction with the sonic hedgehog signaling pathway. Simultaneously, serotonin directly increases calcium movement into the mammary gland and, subsequently, milk. These 2 direct actions of serotonin combine to induce a transient maternal hypocalcemia required to further stimulate PTHrP production and calcium mobilization from bone. Through these 2 routes, serotonin is able to improve maternal calcium concentrations. Furthermore, we have shown that Holstein and Jersey cows appear to regulate calcium in different manners and also respond differently to serotonergic stimulation of the calcium pathway. Our data in rodents and cows indicate that serotonin and calcium are working through a unique feedback loop with PTHrP during lactation to regulate milk calcium and maternal calcium homeostasis.

Tactile/kinesthetic stimulation (TKS) increases tibial speed of sound and urinary osteocalcin (U-MidOC and unOC) in premature infants (29-32weeks PMA).

PubMed

Haley, S; Beachy, J; Ivaska, K K; Slater, H; Smith, S; Moyer-Mileur, L J

2012-10-01

Preterm delivery (<37 weeks post-menstrual age) is associated with suboptimal bone mass. We hypothesized that tactile/kinesthetic stimulation (TKS), a form of infant massage that incorporates kinesthetic movement, would increase bone strength and markers of bone accretion in preterm infants. Preterm, AGA infants (29-32 weeks) were randomly assigned to TKS (N=20) or Control (N=20). Twice daily TKS was provided 6 days per week for 2 weeks. Control infants received the same care without TKS treatment. Treatment was masked to parents, health care providers, and study personnel. Baseline and week two measures were collected for tibial speed of sound (tSOS, m/sec), a surrogate for bone strength, by quantitative ultrasound (Sunlight8000) and urine markers of bone metabolism, pyridinium crosslinks and osteocalcin (U-MidOC and unOC). Infant characteristics at birth and study entry as well as energy/nutrient intake were similar between TKS and Control. TKS intervention attenuated the decrease in tSOS observed in Control infants (p<0.05). Urinary pyridinium crosslinks decreased over time in both TKS and CTL (p<0.005). TKS infants experienced greater increases in urinary osteocalcin (U-MidOC, p<0.001 and unOC, p<0.05). We conclude that TKS improves bone strength in premature infants by attenuating the decrease that normally follows preterm birth. Further, biomarkers of bone metabolism suggest a modification in bone turnover in TKS infants in favor of bone accretion. Taken together, we speculate that TKS improves bone mineralization. Copyright © 2012 Elsevier Inc. All rights reserved.

Triiodothyronine increases calcium loss in a bed rest antigravity model for space flight.

PubMed

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.

Targeting sphingosine-1-phosphate lyase as an anabolic therapy for bone loss.

PubMed

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.

The Effect of Different Bone Marrow Stimulation Techniques on Human Talar Subchondral Bone: A Micro-Computed Tomography Evaluation.

PubMed

Gianakos, Arianna L; Yasui, Youichi; Fraser, Ethan J; Ross, Keir A; Prado, Marcelo P; Fortier, Lisa A; Kennedy, John G

2016-10-01

To evaluate morphological alterations, microarchitectural disturbances, and the extent of bone marrow access to the subchondral bone marrow compartment using micro-computed tomography analysis in different bone marrow stimulation (BMS) techniques. Nine zones in a 3 × 3 grid pattern were assigned to 5 cadaveric talar dome articular surfaces. A 1.00-mm microfracture awl (s.MFX), a 2.00-mm standard microfracture awl (l.MFX), or a 1.25-mm Kirschner wire (K-wire) drill hole was used to penetrate the subchondral bone in each grid zone. Subchondral bone holes and adjacent tissue areas were assessed by micro-computed tomography to analyze adjacent bone area destruction and communicating channels to the bone marrow. Grades 1 to 3 were assigned, where 1 = minimal compression/sclerosis; 2 = moderate compression/sclerosis; 3 = severe compression/sclerosis. Bone volume/total tissue volume, bone surface area/bone volume, trabecular thickness, and trabecular number were calculated in the region of interest. Visual assessment revealed that the s.MFX had significantly more grade 1 holes (P < .001) and that the l.MFX had significantly more poor/grade 3 holes (P = .002). Bone marrow channel assessment showed a statistically significant increase in the number of channels in the s.MFX when compared with both K-wire and l.MFX holes (P < .001). Bone volume fraction for the s.MFX was significantly less than that of the l.MFX (P = .029). BMS techniques using instruments with larger diameters resulted in increased trabecular compaction and sclerosis in areas adjacent to the defect. K-wire and l.MFX techniques resulted in less open communicating bone marrow channels, denoting a reduction in bone marrow access. The results of this study indicate that BMS using larger diameter devices results in greater microarchitecture disturbances. The current study suggests that the choice of a BMS technique should be carefully considered as the results indicate that smaller diameter hole sizes may diminish the amount of microarchitectural disturbances in the subchondral bone. Copyright © 2016 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Novel spinal instrumentation to enhance osteogenesis and fusion: a preliminary study.

PubMed

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.

Circulating osteocrin stimulates bone growth by limiting C-type natriuretic peptide clearance.

PubMed

Kanai, Yugo; Yasoda, Akihiro; Mori, Keita P; Watanabe-Takano, Haruko; Nagai-Okatani, Chiaki; Yamashita, Yui; Hirota, Keisho; Ueda, Yohei; Yamauchi, Ichiro; Kondo, Eri; Yamanaka, Shigeki; Sakane, Yoriko; Nakao, Kazumasa; Fujii, Toshihito; Yokoi, Hideki; Minamino, Naoto; Mukoyama, Masashi; Mochizuki, Naoki; Inagaki, Nobuya

2017-11-01

Although peptides are safe and useful as therapeutics, they are often easily degraded or metabolized. Dampening the clearance system for peptide ligands is a promising strategy for increasing the efficacy of peptide therapies. Natriuretic peptide receptor B (NPR-B) and its naturally occurring ligand, C-type natriuretic peptide (CNP), are potent stimulators of endochondral bone growth, and activating the CNP/NPR-B system is expected to be a powerful strategy for treating impaired skeletal growth. CNP is cleared by natriuretic peptide clearance receptor (NPR-C); therefore, we investigated the effect of reducing the rate of CNP clearance on skeletal growth by limiting the interaction between CNP and NPR-C. Specifically, we generated transgenic mice with increased circulating levels of osteocrin (OSTN) protein, a natural NPR-C ligand without natriuretic activity, and observed a dose-dependent skeletal overgrowth phenotype in these animals. Skeletal overgrowth in OSTN-transgenic mice was diminished in either CNP- or NPR-C-depleted backgrounds, confirming that CNP and NPR-C are indispensable for the bone growth-stimulating effect of OSTN. Interestingly, double-transgenic mice of CNP and OSTN had even higher levels of circulating CNP and additional increases in bone length, as compared with mice with elevated CNP alone. Together, these results support OSTN administration as an adjuvant agent for CNP therapy and provide a potential therapeutic approach for diseases with impaired skeletal growth.

Embryonic stem cells in scaffold-free three-dimensional cell culture: osteogenic differentiation and bone generation.

PubMed

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.

Mineralocorticoid receptor function in bone metabolism and its role in glucocorticoid-induced osteopenia.

PubMed

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.

Free bone graft reconstruction of irradiated facial tissue: Experimental effects of basic fibroblast growth factor stimulation

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

Effects of combined mechanical stimulation on the proliferation and differentiation of pre-osteoblasts

PubMed Central

Kang, Kyung Shin; Lee, Seung-Jae; Lee, Haksue; Moon, Wonkyu

2011-01-01

We observed how combined mechanical stimuli affect the proliferation and differentiation of pre-osteoblasts. For this research, a bioreactor system was developed that can simultaneously stimulate cells with cyclic strain and ultrasound, each of which is known to effectively stimulate bone tissue regeneration. MC3T3-E1 pre-osteoblasts were chosen for bone tissue engineering due to their osteoblast-like characteristics. 3-D scaffolds were fabricated with polycaprolactone and poly-L-lactic acid using the salt leaching method. The cells were stimulated by the bioreactor with cyclic strain and ultrasound. The bioreactor was set at a frequency of 1.0 Hz and 10% strain for cyclic strain and 1.0 MHz and 30 mW/cm2 for ultrasound. Three experimental groups (ultrasound, cyclic strain, and combined stimulation) and a control group were examined. Each group was stimulated for 20 min/day. Mechanical stimuli did not affect MC3T3-E1 cell proliferation significantly up to 10 days when measured with the cell counting kit-8. However, gene expression analysis of collagen type-I, osteocalcin, RUNX2, and osterix revealed that the combined mechanical stimulation accelerated the matrix maturation of MC3T3-E1 cells. These results indicate that the combined mechanical stimulation can enhance the differentiation of pre-osteoblasts more efficiently than simple stimuli, in spite of no effect on cell proliferation. PMID:21532314

Actions of Tamoxifen and Estrogen on Osteoblast Protein Kinase C Expression.

DTIC Science & Technology

1996-07-01

extended period of time over which estrogen deficiency -induced bone loss occurs. Postmenopausal bone loss occurs gradually over several years, and changes...Identification of luteal estrogen-modulated lipid- stimulated kinase as protein kinase C5. J Biol Chem 267:17061-17068. 24. Cutler RE Jr, Maizels ET

Fluorine-18 fluorodeoxyglucose splenic uptake from extramedullary hematopoiesis after granulocyte colony-stimulating factor stimulation.

PubMed

Abdel-Dayem, H M; Rosen, G; El-Zeftawy, H; Naddaf, S; Kumar, M; Atay, S; Cacavio, A

1999-05-01

Two patients with sarcoma, one with recurrent osteosarcoma of the spine and the other with metastatic synovial cell sarcoma, were treated with high-dose chemotherapy that produced severe leukopenia. The patients received granulocyte colony-stimulating factor (G-CSF) to stimulate the bone marrow (480 mg given subcutaneously twice daily for 5 to 7 days); their responses were seen as a marked increase in peripheral leukocyte count with no change in the erythrocyte or platelet counts. The patients had fluorine-18 fluorodeoxyglucose (F-18 FDG) imaging 24 hours after the end of G-CSF treatment. Diffusely increased uptake of F-18 FDG was seen in the bone marrow in both patients. In addition, markedly increased uptake in the spleen was noted in both, indicating that the spleen was the site of extramedullary hematopoiesis. The patients had no evidence of splenic metastases. The first patient had a history of irradiation to the dorsal spine, which was less responsive to G-CSF administration than was the nonirradiated lumbar spine.

Bone anabolics in osteoporosis: Actuality and perspectives

PubMed Central

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

Parathyroid hormone and bone healing.

PubMed

Ellegaard, M; Jørgensen, N R; Schwarz, P

2010-07-01

Fracture healing is a complex process, and a significant number of fractures are complicated by impaired healing and non-union. Impaired healing is prevalent in certain risk groups, such as the elderly, osteoporotics, people with malnutrition, and women after menopause. Currently, no pharmacological treatments are available. There is therefore an unmet need for medications that can stimulate bone healing. Parathyroid hormone (PTH) is the first bone anabolic drug approved for the treatment of osteoporosis, and intriguingly a number of animal studies suggest that PTH could be beneficial in the treatment of fractures and could thus be a potentially new treatment option for induction of fracture healing in humans. Furthermore, fractures in animals with experimental conditions of impaired healing such as aging, estrogen withdrawal, and malnutrition can heal in an expedited manner after PTH treatment. Interestingly, fractures occurring at both cancellous and cortical sites can be treated successfully, indicating that both osteoporotic and nonosteoporotic fractures can be the target of PTH-induced healing. Finally, the data suggest that PTH partly prevents the delay in fracture healing caused by aging. Recently, the first randomized, controlled clinical trial investigating the effect of PTH on fracture healing was published, indicating a possible clinical benefit of PTH treatment in inducing fracture healing. The aim of this article is therefore to review the evidence for the potential of PTH in bone healing, including the underlying mechanisms for this, and to provide recommendations for the clinical testing and use of PTH in the treatment of impaired fracture healing in humans.

CCAAT/enhancer-binding protein delta activates insulin-like growth factor-I gene transcription in osteoblasts. Identification of a novel cyclic AMP signaling pathway in bone

NASA Technical Reports Server (NTRS)

Umayahara, Y.; Ji, C.; Centrella, M.; Rotwein, P.; McCarthy, T. L.

1997-01-01

Insulin-like growth factor-I (IGF-I) plays a key role in skeletal growth by stimulating bone cell replication and differentiation. We previously showed that prostaglandin E2 (PGE2) and other cAMP-activating agents enhanced IGF-I gene transcription in cultured primary rat osteoblasts through promoter 1, the major IGF-I promoter, and identified a short segment of the promoter, termed HS3D, that was essential for hormonal regulation of IGF-I gene expression. We now demonstrate that CCAAT/enhancer-binding protein (C/EBP) delta is a major component of a PGE2-stimulated DNA-protein complex involving HS3D and find that C/EBPdelta transactivates IGF-I promoter 1 through this site. Competition gel shift studies first indicated that a core C/EBP half-site (GCAAT) was required for binding of a labeled HS3D oligomer to osteoblast nuclear proteins. Southwestern blotting and UV-cross-linking studies showed that the HS3D probe recognized a approximately 35-kDa nuclear protein, and antibody supershift assays indicated that C/EBPdelta comprised most of the PGE2-activated gel-shifted complex. C/EBPdelta was detected by Western immunoblotting in osteoblast nuclear extracts after treatment of cells with PGE2. An HS3D oligonucleotide competed effectively with a high affinity C/EBP site from the rat albumin gene for binding to osteoblast nuclear proteins. Co-transfection of osteoblast cell cultures with a C/EBPdelta expression plasmid enhanced basal and PGE2-activated IGF-I promoter 1-luciferase activity but did not stimulate a reporter gene lacking an HS3D site. By contrast, an expression plasmid for the related protein, C/EBPbeta, did not alter basal IGF-I gene activity but did increase the response to PGE2. In osteoblasts and in COS-7 cells, C/EBPdelta, but not C/EBPbeta, transactivated a reporter gene containing four tandem copies of HS3D fused to a minimal promoter; neither transcription factor stimulated a gene with four copies of an HS3D mutant that was unable to bind osteoblast nuclear proteins. These results identify C/EBPdelta as a hormonally activated inducer of IGF-I gene transcription in osteoblasts and show that the HS3D element within IGF-I promoter 1 is a high affinity binding site for this protein.

Stimulation of osteogenic differentiation in human osteoprogenitor cells by pulsed electromagnetic fields: an in vitro study

PubMed Central

2010-01-01

Background Although pulsed electromagnetic field (PEMF) stimulation may be clinically beneficial during fracture healing and for a wide range of bone disorders, there is still debate on its working mechanism. Mesenchymal stem cells are likely mediators facilitating the observed clinical effects of PEMF. Here, we performed in vitro experiments to investigate the effect of PEMF stimulation on human bone marrow-derived stromal cell (BMSC) metabolism and, specifically, whether PEMF can stimulate their osteogenic differentiation. Methods BMSCs derived from four different donors were cultured in osteogenic medium, with the PEMF treated group being continuously exposed to a 15 Hz, 1 Gauss EM field, consisting of 5-millisecond bursts with 5-microsecond pulses. On culture day 1, 5, 9, and 14, cells were collected for biochemical analysis (DNA amount, alkaline phosphatase activity, calcium deposition), expression of various osteoblast-relevant genes and activation of extracellular signal-regulated kinase (ERK) signaling. Differences between treated and control groups were analyzed using the Wilcoxon signed rank test, and considered significant when p < 0.05. Results Biochemical analysis revealed significant, differentiation stage-dependent, PEMF-induced differences: PEMF increased mineralization at day 9 and 14, without altering alkaline phosphatase activity. Cell proliferation, as measured by DNA amounts, was not affected by PEMF until day 14. Here, DNA content stagnated in PEMF treated group, resulting in less DNA compared to control. Quantitative RT-PCR revealed that during early culture, up to day 9, PEMF treatment increased mRNA levels of bone morphogenetic protein 2, transforming growth factor-beta 1, osteoprotegerin, matrix metalloproteinase-1 and -3, osteocalcin, and bone sialoprotein. In contrast, receptor activator of NF-κB ligand expression was primarily stimulated on day 14. ERK1/2 phosphorylation was not affected by PEMF stimulation. Conclusions PEMF exposure of differentiating human BMSCs enhanced mineralization and seemed to induce differentiation at the expense of proliferation. The osteogenic stimulus of PEMF was confirmed by the up-regulation of several osteogenic marker genes in the PEMF treated group, which preceded the deposition of mineral itself. These findings indicate that PEMF can directly stimulate osteoprogenitor cells towards osteogenic differentiation. This supports the theory that PEMF treatment may recruit these cells to facilitate an osteogenic response in vivo. PMID:20731873

Effect of antiresorptive and anabolic bone therapy on development of osteoarthritis in a posttraumatic rat model of OA.

PubMed

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.

Augmented cartilage regeneration by implantation of cellular versus acellular implants after bone marrow stimulation: a systematic review and meta-analysis of animal studies

PubMed Central

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

Comparison between a β-tricalcium phosphate and an absorbable collagen sponge carrier technology for rhGDF-5-stimulated periodontal wound healing/regeneration.

PubMed

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.

Inulin and oligofructose and mineral metabolism: the evidence from animal trials.

PubMed

Scholz-Ahrens, Katharina E; Schrezenmeir, Jürgen

2007-11-01

Nondigestible oligosaccharides have been shown to increase the absorption of several minerals (calcium, magnesium, in some cases phosphorus) and trace elements (mainly copper, iron, zinc). Inulin-type fructans including oligofructose and fructooligosaccharides derived from sucrose by enzymatic transfructosylation are the best investigated food ingredients in this respect. The stimulation of absorption was more pronounced when the demand for calcium was high, i.e., in animals in the rapid growing stage and in animals with impaired calcium absorption because of either ovariectomy or gastrectomy. Even a small stimulation of calcium absorption increased the mineral accumulation in the skeleton because of its persisting effect over months. Inulin-type fructans stimulated mineral absorption and bone mineral accretion when combined with probiotic lactobacilli and in the presence of antibiotics. Direct comparison of different inulin-type fructans revealed a more pronounced effect by inulin or a mixture of long-chain inulin and oligofructose than by oligofructose alone. Mechanisms on how inulin-type fructans mediate this effect include acidification of the intestinal lumen by short-chain fatty acids increasing solubility of minerals in the gut, enlargement of the absorption surface, increased expression of calcium-binding proteins mainly in the large intestine, modulated expression of bone-relevant cytokines, suppression of bone resorption, increased bioavailability of phytoestrogens, and, via stimulation of beneficial commensal microorganisms, increase of calcium uptake by enterocytes. Under certain conditions, inulin-type fructans may improve mineral absorption by their impact on the amelioration of gut health including stabilization of the intestinal flora and reduction of inflammation. The abundance of reports indicate that inulin-type fructans are promising substances that could help to improve the supply with available calcium in human nutrition and by this contribute to bone health.

Bone marrow-derived dendritic cells under influence of experimental breast cancer and physical activity

PubMed Central

Abdalla, Douglas R.; Gomes, Bruno B. M.; Murta, Eddie F. C.; Michelin, Márcia A.

2017-01-01

Immune cells are required in the immune response against tumours, although sometimes without success. The present study aimed to investigate dendritic cell (DC) maturation in animals with induced immunosuppression that were subjected to physical activity (PA). Immunosuppression was induced using 7,12-dimethyl-benzanthracene (DMBA). A total of 56 Balb/c mice were divided into four groups, including the control group, non-DMBA administered/PA group (GII), DMBA administered/non-PA group (GIII) and the DMBA administered/PA group (GIV). Bone marrow was removed from the leg bones following sacrifice. Bone marrow-derived DCs were stimulated to differentiate by granulocyte-macrophage colony-stimulating factor, interleukin (IL)-4 and tumour necrosis factor-α, after which the phenotype was assessed by flow cytometry and the cytokine profile was assessed using ELISAs. PA significantly increased the percentage of DCs in GII (55.38±2.63%) and GIV (50.1±3.1%) mice, as compared with GI (34.61±1.28%) and GIII (36.25±1.85%) mice (P<0.05). In addition, GIV mice showed a significantly higher level of cluster of differentiation (CD) 80+/CD86+ DCs (76.38±6.31%), as compared with GI (54.03±6.52%) and GIII (52.07±5.74%) mice (P<0.05). Furthermore, GIV mice showed a significantly higher level of CD80+/major histocompatibility complex class II double labelling (P<0.05), as compared with GIV (95.35±1.22%) and GIII (76.15±5.53%) mice. The expression of interferon-γ was significantly increased in GIV mice [5.89 (5.2–7.12)], as compared with GIII mice [2.75 (1.33–4.4)] (P<0.05). Similarly, the expression of IL-12 was markedly increased in GIV mice [1.27 (0.26–2.57)] compared with GIII mice [0.73 (0.44–1.47)], although the difference was not significant (P=0.063). The results of the present study suggested that PA was able to promote the maturation of DCs and their secretion of anti-tumour cytokines. Therefore, PA may emerge as a tool in immunotherapy. PMID:28454269

Bone marrow-derived dendritic cells under influence of experimental breast cancer and physical activity.

PubMed

Abdalla, Douglas R; Gomes, Bruno B M; Murta, Eddie F C; Michelin, Márcia A

2017-03-01

Immune cells are required in the immune response against tumours, although sometimes without success. The present study aimed to investigate dendritic cell (DC) maturation in animals with induced immunosuppression that were subjected to physical activity (PA). Immunosuppression was induced using 7,12-dimethyl-benzanthracene (DMBA). A total of 56 Balb/c mice were divided into four groups, including the control group, non-DMBA administered/PA group (GII), DMBA administered/non-PA group (GIII) and the DMBA administered/PA group (GIV). Bone marrow was removed from the leg bones following sacrifice. Bone marrow-derived DCs were stimulated to differentiate by granulocyte-macrophage colony-stimulating factor, interleukin (IL)-4 and tumour necrosis factor-α, after which the phenotype was assessed by flow cytometry and the cytokine profile was assessed using ELISAs. PA significantly increased the percentage of DCs in GII (55.38±2.63%) and GIV (50.1±3.1%) mice, as compared with GI (34.61±1.28%) and GIII (36.25±1.85%) mice (P<0.05). In addition, GIV mice showed a significantly higher level of cluster of differentiation (CD) 80 + /CD86 + DCs (76.38±6.31%), as compared with GI (54.03±6.52%) and GIII (52.07±5.74%) mice (P<0.05). Furthermore, GIV mice showed a significantly higher level of CD80 + /major histocompatibility complex class II double labelling (P<0.05), as compared with GIV (95.35±1.22%) and GIII (76.15±5.53%) mice. The expression of interferon-γ was significantly increased in GIV mice [5.89 (5.2-7.12)], as compared with GIII mice [2.75 (1.33-4.4)] (P<0.05). Similarly, the expression of IL-12 was markedly increased in GIV mice [1.27 (0.26-2.57)] compared with GIII mice [0.73 (0.44-1.47)], although the difference was not significant (P=0.063). The results of the present study suggested that PA was able to promote the maturation of DCs and their secretion of anti-tumour cytokines. Therefore, PA may emerge as a tool in immunotherapy.

The central nervous system (CNS)-independent anti-bone-resorptive activity of muscle contraction and the underlying molecular and cellular signatures.

PubMed

Qin, Weiping; Sun, Li; Cao, Jay; Peng, Yuanzhen; Collier, Lauren; Wu, Yong; Creasey, Graham; Li, Jianhua; Qin, Yiwen; Jarvis, Jonathan; Bauman, William A; Zaidi, Mone; Cardozo, Christopher

2013-05-10

Mechanisms by which muscle regulates bone are poorly understood. Electrically stimulated muscle contraction reversed elevations in bone resorption and increased Wnt signaling in bone-derived cells after spinal cord transection. Muscle contraction reduced resorption of unloaded bone independently of the CNS, through mechanical effects and, potentially, nonmechanical signals (e.g. myokines). The study provides new insights regarding muscle-bone interactions. Muscle and bone work as a functional unit. Cellular and molecular mechanisms underlying effects of muscle activity on bone mass are largely unknown. Spinal cord injury (SCI) causes muscle paralysis and extensive sublesional bone loss and disrupts neural connections between the central nervous system (CNS) and bone. Muscle contraction elicited by electrical stimulation (ES) of nerves partially protects against SCI-related bone loss. Thus, application of ES after SCI provides an opportunity to study the effects of muscle activity on bone and roles of the CNS in this interaction, as well as the underlying mechanisms. Using a rat model of SCI, the effects on bone of ES-induced muscle contraction were characterized. The SCI-mediated increase in serum C-terminal telopeptide of type I collagen (CTX) was completely reversed by ES. In ex vivo bone marrow cell cultures, SCI increased the number of osteoclasts and their expression of mRNA for several osteoclast differentiation markers, whereas ES significantly reduced these changes; SCI decreased osteoblast numbers, but increased expression in these cells of receptor activator of NF-κB ligand (RANKL) mRNA, whereas ES increased expression of osteoprotegerin (OPG) and the OPG/RANKL ratio. A microarray analysis revealed that ES partially reversed SCI-induced alterations in expression of genes involved in signaling through Wnt, FSH, parathyroid hormone (PTH), oxytocin, and calcineurin/nuclear factor of activated T-cells (NFAT) pathways. ES mitigated SCI-mediated increases in mRNA levels for the Wnt inhibitors DKK1, sFRP2, and sclerostin in ex vivo cultured osteoblasts. Our results demonstrate an anti-bone-resorptive activity of muscle contraction by ES that develops rapidly and is independent of the CNS. The pathways involved, particularly Wnt signaling, suggest future strategies to minimize bone loss after immobilization.

Synergistic action of the benzene metabolite hydroquinone on myelopoietic stimulating activity of granulocyte/macrophage colony-stimulating factor in vitro

NASA Technical Reports Server (NTRS)

Irons, R. D.; Stillman, W. S.; Colagiovanni, D. B.; Henry, V. A.; Clarkson, T. W. (Principal Investigator)

1992-01-01

The effects of in vitro pretreatment with benzene metabolites on colony-forming response of murine bone marrow cells stimulated with recombinant granulocyte/macrophage colony-stimulating factor (rGM-CSF) were examined. Pretreatment with hydroquinone (HQ) at concentrations ranging from picomolar to micromolar for 30 min resulted in a 1.5- to 4.6-fold enhancement in colonies formed in response to rGM-CSF that was due to an increase in granulocyte/macrophage colonies. The synergism equaled or exceeded that reported for the effects of interleukin 1, interleukin 3, or interleukin 6 with GM-CSF. Optimal enhancement was obtained with 1 microM HQ and was largely independent of the concentration of rGM-CSF. Pretreatment with other authentic benzene metabolites, phenol and catechol, and the putative metabolite trans, trans-muconaldehyde did not enhance growth factor response. Coadministration of phenol and HQ did not enhance the maximal rGM-CSF response obtained with HQ alone but shifted the optimal concentration to 100 pM. Synergism between HQ and rGM-CSF was observed with nonadherent bone marrow cells and lineage-depleted bone marrow cells, suggesting an intrinsic effect on recruitment of myeloid progenitor cells not normally responsive to rGM-CSF. Alterations in differentiation in a myeloid progenitor cell population may be of relevance in the pathogenesis of acute myelogenous leukemia secondary to drug or chemical exposure.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aerts-Kaya, Fatima S.F.; Visser, Trudi P.; Arshad, Shazia

Purpose: 5-Androstene-3{beta},17{beta}-diol (5-AED) stimulates recovery of hematopoiesis after exposure to radiation. To elucidate its cellular targets, the effects of 5-AED alone and in combination with (pegylated) granulocyte colony-stimulating factor and thrombopoietin (TPO) on immature hematopoietic progenitor cells were evaluated following total body irradiation. Methods and Materials: BALB/c mice were exposed to radiation delivered as a single or as a fractionated dose, and recovery of bone marrow progenitors and peripheral blood parameters was assessed. Results: BALB/c mice treated with 5-AED displayed accelerated multilineage blood cell recovery and elevated bone marrow (BM) cellularity and numbers of progenitor cells. The spleen colony-forming unitmore » (CFU-S) assay, representing the life-saving short-term repopulating cells in BM of irradiated donor mice revealed that combined treatment with 5-AED plus TPO resulted in a 20.1-fold increase in CFU-S relative to that of placebo controls, and a 3.7 and 3.1-fold increase in comparison to 5-AED and TPO, whereas no effect was seen of Peg-G-CSF with or without 5-AED. Contrary to TPO, 5-AED also stimulated reconstitution of the more immature marrow repopulating (MRA) cells. Conclusions: 5-AED potently counteracts the hematopoietic effects of radiation-induced myelosuppression and promotes multilineage reconstitution by stimulating immature bone marrow cells in a pattern distinct from, but synergistic with TPO.« less

Orthobiologics in Pediatric Sports Medicine.

PubMed

Bray, Christopher C; Walker, Clark M; Spence, David D

2017-07-01

Orthobiologics are biological substances that allow injured muscles, tendons, ligaments, and bone to heal more quickly. They are found naturally in the body; at higher concentrations they can aid in the healing process. These substances include autograft bone, allograft bone, demineralized bone matrix, bone morphogenic proteins, growth factors, stem cells, plasma-rich protein, and ceramic grafts. Their use in sports medicine has exploded in efforts to increase graft incorporation, stimulate healing, and get athletes back to sport with problems including anterior cruciate ligament ruptures, tendon ruptures, cartilage injuries, and fractures. This article reviews orthobiologics and their applications in pediatric sports medicine. Copyright © 2017 Elsevier Inc. All rights reserved.

Evaluating Device Design and Cleanability of Orthopedic Device Models Contaminated with a Clinically Relevant Bone Test Soil.

PubMed

Lucas, Anne D; Nagaraja, Srinidhi; Gordon, Edward A; Hitchins, Victoria M

2015-01-01

Reusable medical devices need to be cleaned prior to disinfection or sterilization and subsequent use to prevent infections. The cleanability of medical devices depends in part on the design of the device. This study examined how models of orthopedic medical devices of increasing complexity retain calcium phosphate bone cement, a relevant test soil for these devices. The dye Alizarin Red S and micro-computed tomography (μCT) were used to assess the amount and location of bone cement debris in a series of model orthopedic devices. Testing was performed after soiling and cleaning once, and soiling and cleaning 10 times. The color change of the dye after reacting with the bone cement was useful for indicating the presence of bone cement in these models. High-resolution μCT analysis provided the volume and location of the bone cement. Models that were more complex retained significantly more bone debris than simpler designs. Model devices repeatedly soiled and cleaned 10 times retained significantly more bone debris than those soiled and cleaned once. Significantly more bone cement was retained in the more complex lumen structures. This information may be useful in designing reusable orthopedic devices, and other complex medical devices with lumens.

The association of human mesenchymal stem cells with BMP-7 improves bone regeneration of critical-size segmental bone defects in athymic rats.

PubMed

Burastero, Giorgio; Scarfì, Sonia; Ferraris, Chiara; Fresia, Chiara; Sessarego, Nadia; Fruscione, Floriana; Monetti, Francesco; Scarfò, Francesca; Schupbach, Peter; Podestà, Marina; Grappiolo, Guido; Zocchi, Elena

2010-07-01

Critical size segmental bone defects are still a major challenge in reconstructive orthopedic surgery. Transplantation of human mesenchymal stem cells (hMSC) has been proposed as an alternative to autogenous bone graft, as MSC can be expanded in vitro and induced to differentiate into bone-regenerating osteoblasts by several bone morphogenetic proteins (BMP). The aim of this study was to investigate whether the association of hMSC and BMP-7, with providing the necessary scaffold to fill the bone loss, improved bone regeneration in a rat model of critical size segmental bone defect, compared to treatment with either hMSC or BMP-7 and the matrix. In addition, we tested whether pre-treatment of hMSC with cyclic ADP-ribose (cADPR), an intracellular Ca2+ mobilizer previously shown to accelerate the in vitro expansion of hMSC (Scarfì S et al, Stem Cells, 2008), affected the osteoinductive capacity of the cells in vivo. X-ray analysis, performed 2, 10 and 16 weeks after transplantation, revealed a significantly higher score in the rats treated with hMSC and BMP-7 compared to controls, receiving either hMSC or BMP-7. Microtomography and histological analysis, performed 16weeks after transplantation, confirmed the improved bone regeneration in the animals treated with the association of hMSC and BMP-7 compared to controls. Pre-treatment with cADPR to stimulate hMSC proliferation in vitro did not affect the bone regenerating capacity of the cells in vivo. These results indicate that the association of in vitro expanded hMSC with BMP-7 provide a better osteoinductive graft compared to either hMSC or BMP-7 alone. Moreover, cADPR may be used to stimulate hMSC proliferation in vitro in order to reduce the time required to obtain a transplantable number of cells, with no adverse effect on the bone regenerating capacity of hMSC. 2010 Elsevier Inc. All rights reserved.

Investigation of the inverse piezoelectric effect of trabecular bone on a micrometer length scale using synchrotron radiation.

PubMed

Wieland, D C F; Krywka, C; Mick, E; Willumeit-Römer, R; Bader, R; Kluess, D

2015-10-01

In the present paper we have investigated the impact of electro stimulation on microstructural parameters of the major constituents of bone, hydroxyapatite and collagen. Therapeutic approaches exhibit an improved healing rate under electric fields. However, the underlying mechanism is not fully understood so far. In this context one possible effect which could be responsible is the inverse piezo electric effect at bone structures. Therefore, we have carried out scanning X-ray microdiffraction experiments, i.e. we recorded X-ray diffraction data with micrometer resolution using synchrotron radiation from trabecular bone samples in order to investigate how the bone matrix reacts to an applied electric field. Different samples were investigated, where the orientation of the collagen matrix differed with respect to the applied electric field. Our experiments aimed to determine whether the inverse piezo electric effect could have a significant impact on the improved bone regeneration owing to electrostimulative therapy. Our data suggest that strain is in fact induced in bone by the collagen matrix via the inverse piezo electric effect which occurs in the presence of an adequately oriented electric field. The magnitude of the underlying strain is in a range where bone cells are able to detect it. In our study we report on the piezoelectric effect in bone which was already discovered and explored on a macro scale in the 1950. Clinical approaches utilize successfully electro stimulation to enhance bone healing but the exact mechanisms taking place are still a matter of debate. We have measured the stress distribution with micron resolution in trabecular bone to determine the piezo electric induced stress. Our results show that the magnitude of the induced stress is big enough to be sensed by cells and therefore, could be a trigger for bone remodeling and growth. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Subchondral pre-solidified chitosan/blood implants elicit reproducible early osteochondral wound-repair responses including neutrophil and stromal cell chemotaxis, bone resorption and repair, enhanced repair tissue integration and delayed matrix deposition

PubMed Central

2013-01-01

Background In this study we evaluated a novel approach to guide the bone marrow-driven articular cartilage repair response in skeletally aged rabbits. We hypothesized that dispersed chitosan particles implanted close to the bone marrow degrade in situ in a molecular mass-dependent manner, and attract more stromal cells to the site in aged rabbits compared to the blood clot in untreated controls. Methods Three microdrill hole defects, 1.4 mm diameter and 2 mm deep, were created in both knee trochlea of 30 month-old New Zealand White rabbits. Each of 3 isotonic chitosan solutions (150, 40, 10 kDa, 80% degree of deaceylation, with fluorescent chitosan tracer) was mixed with autologous rabbit whole blood, clotted with Tissue Factor to form cylindrical implants, and press-fit in drill holes in the left knee while contralateral holes received Tissue Factor or no treatment. At day 1 or day 21 post-operative, defects were analyzed by micro-computed tomography, histomorphometry and stereology for bone and soft tissue repair. Results All 3 implants filled the top of defects at day 1 and were partly degraded in situ at 21 days post-operative. All implants attracted neutrophils, osteoclasts and abundant bone marrow-derived stromal cells, stimulated bone resorption followed by new woven bone repair (bone remodeling) and promoted repair tissue-bone integration. 150 kDa chitosan implant was less degraded, and elicited more apoptotic neutrophils and bone resorption than 10 kDa chitosan implant. Drilled controls elicited a poorly integrated fibrous or fibrocartilaginous tissue. Conclusions Pre-solidified implants elicit stromal cells and vigorous bone plate remodeling through a phase involving neutrophil chemotaxis. Pre-solidified chitosan implants are tunable by molecular mass, and could be beneficial for augmented marrow stimulation therapy if the recruited stromal cells can progress to bone and cartilage repair. PMID:23324433

Patient-Derived Human Induced Pluripotent Stem Cells From Gingival Fibroblasts Composited With Defined Nanohydroxyapatite/Chitosan/Gelatin Porous Scaffolds as Potential Bone Graft Substitutes.

PubMed

Ji, Jun; Tong, Xin; Huang, Xiaofeng; Zhang, Junfeng; Qin, Haiyan; Hu, Qingang

2016-01-01

Human embryonic stem cells and adult stem cells have always been the cell source for bone tissue engineering. However, their limitations are obvious, including ethical concerns and/or a short lifespan. The use of human induced pluripotent stem cells (hiPSCs) could avoid these problems. Nanohydroxyapatite (nHA) is an important component of natural bone and bone tissue engineering scaffolds. However, its regulation on osteogenic differentiation with hiPSCs from human gingival fibroblasts (hGFs) is unknown. The purpose of the present study was to investigate the osteogenic differentiation of hiPSCs from patient-derived hGFs regulated by nHA/chitosan/gelatin (HCG) scaffolds with different nHA ratios, such as HCG-111 (1 wt/vol% nHA) and HCG-311 (3 wt/vol% nHA). First, hGFs were reprogrammed into hiPSCs, which have enhanced osteogenic differentiation capability. Second, HCG-111 and HCG-311 scaffolds were successfully synthesized. Finally, hiPSC/HCG complexes were cultured in vitro or subcutaneously transplanted into immunocompromised mice in vivo. The osteogenic differentiation effects of two types of HCG scaffolds on hiPSCs were assessed for up to 12 weeks. The results showed that HCG-311 increased osteogenic-related gene expression of hiPSCs in vitro proved by quantitative real-time polymerase chain reaction, and hiPSC/HCG-311 complexes formed much bone-like tissue in vivo, indicated by cone-beam computed tomography imaging, H&E staining, Masson staining, and RUNX-2, OCN immunohistochemistry staining. In conclusion, our study has shown that osteogenic differentiation of hiPSCs from hGFs was improved by HCG-311. The mechanism might be that the nHA addition stimulates osteogenic marker expression of hiPSCs from hGFs. Our work has provided an innovative autologous cell-based bone tissue engineering approach with soft tissues such as clinically abundant gingiva. The present study focused on patient-personalized bone tissue engineering. Human induced pluripotent stem cells (hiPSCs) were established from clinically easily derived human gingival fibroblasts (hGFs) and defined nanohydroxyapatite/chitosan/gelatin (HCG) scaffolds. hiPSCs derived from hGFs had better osteogenesis capability than that of hGFs. More interestingly, osteogenic differentiation of hiPSCs from hGFs was elevated significantly when composited with HCG-311 scaffolds in vitro and in vivo. The present study has uncovered the important role of different nHA ratios in HCG scaffolds in osteogenesis induction of hiPSCs derived from hGFs. This technique could serve as a potential innovative approach for bone tissue engineering, especially large bone regeneration clinically. ©AlphaMed Press.

Patient-Derived Human Induced Pluripotent Stem Cells From Gingival Fibroblasts Composited With Defined Nanohydroxyapatite/Chitosan/Gelatin Porous Scaffolds as Potential Bone Graft Substitutes

PubMed Central

Ji, Jun; Tong, Xin; Huang, Xiaofeng; Zhang, Junfeng

2016-01-01

Human embryonic stem cells and adult stem cells have always been the cell source for bone tissue engineering. However, their limitations are obvious, including ethical concerns and/or a short lifespan. The use of human induced pluripotent stem cells (hiPSCs) could avoid these problems. Nanohydroxyapatite (nHA) is an important component of natural bone and bone tissue engineering scaffolds. However, its regulation on osteogenic differentiation with hiPSCs from human gingival fibroblasts (hGFs) is unknown. The purpose of the present study was to investigate the osteogenic differentiation of hiPSCs from patient-derived hGFs regulated by nHA/chitosan/gelatin (HCG) scaffolds with different nHA ratios, such as HCG-111 (1 wt/vol% nHA) and HCG-311 (3 wt/vol% nHA). First, hGFs were reprogrammed into hiPSCs, which have enhanced osteogenic differentiation capability. Second, HCG-111 and HCG-311 scaffolds were successfully synthesized. Finally, hiPSC/HCG complexes were cultured in vitro or subcutaneously transplanted into immunocompromised mice in vivo. The osteogenic differentiation effects of two types of HCG scaffolds on hiPSCs were assessed for up to 12 weeks. The results showed that HCG-311 increased osteogenic-related gene expression of hiPSCs in vitro proved by quantitative real-time polymerase chain reaction, and hiPSC/HCG-311 complexes formed much bone-like tissue in vivo, indicated by cone-beam computed tomography imaging, H&E staining, Masson staining, and RUNX-2, OCN immunohistochemistry staining. In conclusion, our study has shown that osteogenic differentiation of hiPSCs from hGFs was improved by HCG-311. The mechanism might be that the nHA addition stimulates osteogenic marker expression of hiPSCs from hGFs. Our work has provided an innovative autologous cell-based bone tissue engineering approach with soft tissues such as clinically abundant gingiva. Significance The present study focused on patient-personalized bone tissue engineering. Human induced pluripotent stem cells (hiPSCs) were established from clinically easily derived human gingival fibroblasts (hGFs) and defined nanohydroxyapatite/chitosan/gelatin (HCG) scaffolds. hiPSCs derived from hGFs had better osteogenesis capability than that of hGFs. More interestingly, osteogenic differentiation of hiPSCs from hGFs was elevated significantly when composited with HCG-311 scaffolds in vitro and in vivo. The present study has uncovered the important role of different nHA ratios in HCG scaffolds in osteogenesis induction of hiPSCs derived from hGFs. This technique could serve as a potential innovative approach for bone tissue engineering, especially large bone regeneration clinically. PMID:26586776

Osteoclast fusion is initiated by a small subset of RANKL-stimulated monocyte progenitors, which can fuse to RANKL-unstimulated progenitors.

PubMed

Levaot, Noam; Ottolenghi, Aner; Mann, Mati; Guterman-Ram, Gali; Kam, Zvi; Geiger, Benjamin

2015-10-01

Osteoclasts are multinucleated, bone-resorbing cells formed via fusion of monocyte progenitors, a process triggered by prolonged stimulation with RANKL, the osteoclast master regulator cytokine. Monocyte fusion into osteoclasts has been shown to play a key role in bone remodeling and homeostasis; therefore, aberrant fusion may be involved in a variety of bone diseases. Indeed, research in the last decade has led to the discovery of genes regulating osteoclast fusion; yet the basic cellular regulatory mechanism underlying the fusion process is poorly understood. Here, we applied a novel approach for tracking the fusion processes, using live-cell imaging of RANKL-stimulated and non-stimulated progenitor monocytes differentially expressing dsRED or GFP, respectively. We show that osteoclast fusion is initiated by a small (~2.4%) subset of precursors, termed "fusion founders", capable of fusing either with other founders or with non-stimulated progenitors (fusion followers), which alone, are unable to initiate fusion. Careful examination indicates that the fusion between a founder and a follower cell consists of two distinct phases: an initial pairing of the two cells, typically lasting 5-35 min, during which the cells nevertheless maintain their initial morphology; and the fusion event itself. Interestingly, during the initial pre-fusion phase, a transfer of the fluorescent reporter proteins from nucleus to nucleus was noticed, suggesting crosstalk between the founder and follower progenitors via the cytoplasm that might directly affect the fusion process, as well as overall transcriptional regulation in the developing heterokaryon. Copyright © 2015 Elsevier Inc. All rights reserved.

Response characteristics of periodontal mechanoreceptors to mechanical stimulation of canine and incisor teeth in the cat.

PubMed

Tabata, T; Suzuki, T; Watanabe, M

1995-09-01

The alveolar bone that overlies the labial aspect of the root of the right lower canine tooth was pared down until paper thin. Thirty-five periodontal mechanosensitive (PM) units sensitive to stimulation of the canine and incisor and to punctate stimulation through the thinned bone of the periodontal ligament of the canine were recorded from the inferior alveolar nerve rostral to the masseter muscle. The units showed a sustained and directionally selective response to pressure applied to the teeth. The optimal directions of stimulation for each tooth in the receptive field were parallel and oriented linguolabially. When the canine was stimulated mechanically in the optimal stimulus direction, the interspike intervals of the responses were relatively regular in most PM units (91%). The conditioning and test stimuli were applied to the adjacent canine and third incisor. The conditioning stimulus (0.10 N) was given to one of these teeth in the optimal stimulus direction. The test stimulus (0.02 N or 0.05 N) was applied to the adjacent tooth in the opposite direction in order to examine the effect of mechanical spreading of the conditioning stimulus on the adjacent tooth. In most PM units, the spike discharges evoked by the conditioning stimulus given to the incisor were stopped by the test stimulus given to the canine. When the given stimuli were reversed, the firings evoked by the conditioning stimulus were slightly depressed by the test stimulus. After removing the spot-like PM receptor site(s) in the paper-thin area of bone, all units but one did not respond to stimulation. These results provide evidence that neurones with multiple-tooth receptive fields and regular spike-interval responses recorded from the inferior alveolar nerve come from the mechanical spreading effect of the stimulation of one tooth on an adjacent tooth through the trans-septal fibre system and that neurones with irregular-interval responses are due to the ramification of PM fibres peripherally.

Journey into Bone Models: A Review

PubMed Central

Scheinpflug, Julia; Pfeiffenberger, Moritz; Damerau, Alexandra; Schwarz, Franziska; Textor, Martin; Lang, Annemarie

2018-01-01

Bone is a complex tissue with a variety of functions, such as providing mechanical stability for locomotion, protection of the inner organs, mineral homeostasis and haematopoiesis. To fulfil these diverse roles in the human body, bone consists of a multitude of different cells and an extracellular matrix that is mechanically stable, yet flexible at the same time. Unlike most tissues, bone is under constant renewal facilitated by a coordinated interaction of bone-forming and bone-resorbing cells. It is thus challenging to recreate bone in its complexity in vitro and most current models rather focus on certain aspects of bone biology that are of relevance for the research question addressed. In addition, animal models are still regarded as the gold-standard in the context of bone biology and pathology, especially for the development of novel treatment strategies. However, species-specific differences impede the translation of findings from animal models to humans. The current review summarizes and discusses the latest developments in bone tissue engineering and organoid culture including suitable cell sources, extracellular matrices and microfluidic bioreactor systems. With available technology in mind, a best possible bone model will be hypothesized. Furthermore, the future need and application of such a complex model will be discussed. PMID:29748516

Journey into Bone Models: A Review.

PubMed

Scheinpflug, Julia; Pfeiffenberger, Moritz; Damerau, Alexandra; Schwarz, Franziska; Textor, Martin; Lang, Annemarie; Schulze, Frank

2018-05-10

Bone is a complex tissue with a variety of functions, such as providing mechanical stability for locomotion, protection of the inner organs, mineral homeostasis and haematopoiesis. To fulfil these diverse roles in the human body, bone consists of a multitude of different cells and an extracellular matrix that is mechanically stable, yet flexible at the same time. Unlike most tissues, bone is under constant renewal facilitated by a coordinated interaction of bone-forming and bone-resorbing cells. It is thus challenging to recreate bone in its complexity in vitro and most current models rather focus on certain aspects of bone biology that are of relevance for the research question addressed. In addition, animal models are still regarded as the gold-standard in the context of bone biology and pathology, especially for the development of novel treatment strategies. However, species-specific differences impede the translation of findings from animal models to humans. The current review summarizes and discusses the latest developments in bone tissue engineering and organoid culture including suitable cell sources, extracellular matrices and microfluidic bioreactor systems. With available technology in mind, a best possible bone model will be hypothesized. Furthermore, the future need and application of such a complex model will be discussed.

Demineralised human dentine matrix stimulates the expression of VEGF and accelerates the bone repair in tooth sockets of rats.

PubMed

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.

Clonidine reduces norepinephrine and improves bone marrow function in a rodent model of lung contusion, hemorrhagic shock, and chronic stress.

PubMed

Alamo, Ines G; Kannan, Kolenkode B; Ramos, Harry; Loftus, Tyler J; Efron, Philip A; Mohr, Alicia M

2017-03-01

Propranolol has been shown previously to restore bone marrow function and improve anemia after lung contusion/hemorrhagic shock. We hypothesized that daily clonidine administration would inhibit central sympathetic outflow and restore bone marrow function in our rodent model of lung contusion/hemorrhagic shock with chronic stress. Male Sprague-Dawley rats underwent 6 days of restraint stress after lung contusion/hemorrhagic shock during which the animals received clonidine (75 μg/kg) after the restraint stress. On postinjury day 7, we assessed urine norepinephrine, blood hemoglobin, plasma granulocyte colony stimulating factor, and peripheral blood mobilization of hematopoietic progenitor cells, as well as bone marrow cellularity and erythroid progenitor cell growth. The addition of clonidine to lung contusion/hemorrhagic shock with chronic restraint stress significantly decreased urine norepinephrine levels, improved bone marrow cellularity, restored erythroid progenitor colony growth, and improved hemoglobin (14.1 ± 0.6 vs 10.8 ± 0.6 g/dL). The addition of clonidine to lung contusion/hemorrhagic shock with chronic restraint stress significantly decreased hematopoietic progenitor cells mobilization and restored granulocyte colony stimulating factor levels. After lung contusion/hemorrhagic shock with chronic restraint stress, daily administration of clonidine restored bone marrow function and improved anemia. Alleviating chronic stress and decreasing norepinephrine is a key therapeutic target to improve bone marrow function after severe injury. Copyright © 2016 Elsevier Inc. All rights reserved.

Diaphyseal long bone nonunions - types, aetiology, economics, and treatment recommendations.

PubMed

Rupp, Markus; Biehl, Christoph; Budak, Matthäus; Thormann, Ulrich; Heiss, Christian; Alt, Volker

2018-02-01

The intention of the current article is to review the epidemiology with related socioeconomic costs, pathophysiology, and treatment options for diaphyseal long bone delayed unions and nonunions. Diaphyseal nonunions in the tibia and in the femur are estimated to occur 4.6-8% after modern intramedullary nailing of closed fractures with an even much higher risk in open fractures. There is a high socioeconomic burden for long bone nonunions mainly driven by indirect costs, such as productivity losses due to long treatment duration. The classic classification of Weber and Cech of the 1970s is based on the underlying biological aspect of the nonunion differentiating between "vital" (hypertrophic) and "avital" (hypo-/atrophic) nonunions, and can still be considered to represent the basis for basic evaluation of nonunions. The "diamond concept" units biomechanical and biological aspects and provides the pre-requisites for successful bone healing in nonunions. For humeral diaphyseal shaft nonunions, excellent results for augmentation plating were reported. In atrophic humeral shaft nonunions, compression plating with stimulation of bone healing by bone grafting or BMPs seem to be the best option. For femoral and tibial diaphyseal shaft fractures, dynamization of the nail is an atraumatic, effective, and cheap surgical possibility to achieve bony consolidation, particularly in delayed nonunions before 24 weeks after initial surgery. In established hypertrophic nonunions in the tibia and femur, biomechanical stability should be addressed by augmentation plating or exchange nailing. Hypotrophic or atrophic nonunions require additional biological stimulation of bone healing for augmentation plating.

Bone Tissue Response to Porous and Functionalized Titanium and Silica Based Coatings

PubMed Central

Chaudhari, Amol; Braem, Annabel; Vleugels, Jozef; Martens, Johan A.; Naert, Ignace; Cardoso, Marcio Vivan; Duyck, Joke

2011-01-01

Background Topography and presence of bio-mimetic coatings are known to improve osseointegration. The objective of this study was to evaluate the bone regeneration potential of porous and osteogenic coatings. Methodology Six-implants [Control (CTR); porous titanium coatings (T1, T2); thickened titanium (Ti) dioxide layer (TiO2); Amorphous Microporous Silica (AMS) and Bio-active Glass (BAG)] were implanted randomly in tibiae of 20-New Zealand white rabbits. The animals were sacrificed after 2 or 4 weeks. The samples were analyzed histologically and histomorphometrically. In the initial bone-free areas (bone regeneration areas (BRAs)), the bone area fraction (BAF) was evaluated in the whole cavity (500 µm, BAF-500), in the implant vicinity (100 µm, BAF-100) and further away (100–500 µm, BAF-400) from the implant. Bone-to-implant contact (BIC-BAA) was measured in the areas where the implants were installed in contact to the host bone (bone adaptation areas (BAAs)) to understand and compare the bone adaptation. Mixed models were used for statistical analysis. Principal Findings After 2 weeks, the differences in BAF-500 for different surfaces were not significant (p>0.05). After 4 weeks, a higher BAF-500 was observed for BAG than CTR. BAF-100 for AMS was higher than BAG and BAF-400 for BAG was higher than CTR and AMS. For T1 and AMS, the bone regeneration was faster in the 100-µm compared to the 400-µm zone. BIC-BAA for AMS and BAG was lower after 4 than 2 weeks. After 4 weeks, BIC-BAA for BAG was lower than AMS and CTR. Conclusions BAG is highly osteogenic at a distance from the implant. The porous titanium coatings didn't stimulate bone regeneration but allowed bone growth into the pores. Although AMS didn't stimulate higher bone response, it has a potential of faster bone growth in the vicinity compared to further away from the surface. BIC-BAA data were inconclusive to understand the bone adaptation. PMID:21935382

Unliganded estrogen receptor α stimulates bone sialoprotein gene expression.

PubMed

Takai, Hideki; Matsumura, Hiroyoshi; Matsui, Sari; Kim, Kyung Mi; Mezawa, Masaru; Nakayama, Yohei; Ogata, Yorimasa

2014-04-10

Estrogen is one of the steroid hormones essential for skeletal development. The estrogen receptor (ER) is a transcription factor and a member of the steroid receptor superfamily. There are two different forms of the ER, usually referred to as α and β, each encoded by a separate gene. Hormone-activated ERs form dimers, since the two forms are coexpressed in many cell types. Bone sialoprotein (BSP) is a tissue-specific acidic glycoprotein that is expressed by differentiated osteoblasts, odontoblasts and cementoblasts during the initial formation of mineralized tissue. To determine the molecular basis of the tissue-specific expression of BSP and its regulation by estrogen and the ER, we have analyzed the effects of β-estradiol and ERα on BSP gene transcription. ERα protein levels were increased after ERα overexpression in ROS17/2.8 cells. While BSP mRNA levels were increased by ERα overexpression, the endogenous and overexpressed BSP mRNA levels were not changed by β-estradiol (10(-8)M, 24 h). Luciferase activities of different sized BSP promoter constructs (pLUC3~6) were increased by ERα overexpression, whereas basal and induced luciferase activities by ERα overexpression were not influenced by β-estradiol. Effects of ERα overexpression were 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 ERα overexpression increased binding to the CRE and AP1/GRE elements. Notably, the CRE-protein complexes were disrupted by ERα, CREB and phospho-CREB antibodies. The AP1/GRE-protein complexes were supershifted by the c-Fos antibody. These studies demonstrate that ERα stimulates BSP gene transcription in a ligand-independent manner by targeting the CRE and AP1/GRE elements in the rat BSP gene promoter. Copyright © 2014 Elsevier B.V. All rights reserved.

Osteoinductive ceramics as a synthetic alternative to autologous bone grafting

PubMed Central

Yuan, Huipin; Fernandes, Hugo; Habibovic, Pamela; de Boer, Jan; Barradas, Ana M. C.; de Ruiter, Ad; Walsh, William R.; van Blitterswijk, Clemens A.; de Bruijn, Joost D.

2010-01-01

Biomaterials can be endowed with biologically instructive properties by changing basic parameters such as elasticity and surface texture. However, translation from in vitro proof of concept to clinical application is largely missing. Porous calcium phosphate ceramics are used to treat small bone defects but in general do not induce stem cell differentiation, which is essential for regenerating large bone defects. Here, we prepared calcium phosphate ceramics with varying physicochemical and structural characteristics. Microporosity correlated to their propensity to stimulate osteogenic differentiation of stem cells in vitro and bone induction in vivo. Implantation in a large bone defect in sheep unequivocally demonstrated that osteoinductive ceramics are equally efficient in bone repair as autologous bone grafts. Our results provide proof of concept for the clinical application of “smart” biomaterials. PMID:20643969

A reciprocal regulatory interaction between megakaryocytes, bone cells, and hematopoietic stem cells.

PubMed

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.

iNOS-Derived Nitric Oxide Stimulates Osteoclast Activity and Alveolar Bone Loss in Ligature-Induced Periodontitis in Rats

PubMed Central

Herrera, Bruno S.; Martins-Porto, Rodrigo; Maia-Dantas, Aline; Campi, Paula; Spolidorio, Luis C.; Costa, Soraia K.P.; Van Dyke, Thomas E.; Gyurko, Robert; Muscara, Marcelo N.

2012-01-01

Background Inflammatory stimuli activate inducible nitric oxide synthase (iNOS) in a variety of cell types, including osteoclasts (OC) and osteoblasts, resulting in sustained NO production. In this study, we evaluate the alveolar bone loss in rats with periodontitis under long-term iNOS inhibition, and the differentiation and activity of OC from iNOS-knockout (KO) mice in vitro. Methods Oral aminoguanidine (an iNOS inhibitor) or water treatment was started 2 weeks before induction of periodontitis. Rats were sacrificed 3, 7, or 14 days after ligature placement, and alveolar bone loss was evaluated. In vitro OC culture experiments were also performed to study the differentiation of freshly isolated bone marrow cells from both iNOS KO and wild-type C57BL/6 mice. OC were counted 6 days later after tartrate-resistant acid phosphatase staining (a marker of osteoclast identity), and bone resorption activity was assessed by counting the number of resorption pits on dentin disks. Results Rats with ligature showed progressive and significant alveolar bone loss compared to sham animals, and aminoguanidine treatment significantly inhibited ligature-induced bone loss at 7 and 14 days after the induction. In comparison to bone marrow cells from wild-type mice, cells from iNOS KO mice showed decreased OC growth and the resulting OC covered a smaller culture dish area and generated fewer resorption pit counts. Conclusion Our results demonstrate that iNOS inhibition prevents alveolar bone loss in a rat model of ligature-induced periodontitis, thus confirming that iNOS-derived NO plays a crucial role in the pathogenesis of periodontitis, probably by stimulating OC differentiation and activity. PMID:21417589

Novel oxysterols have pro-osteogenic and anti-adipogenic effects in vitro and induce spinal fusion in vivo.

PubMed

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.

Bringing new life to damaged bone: the importance of angiogenesis in bone repair and regeneration.

PubMed

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.

Periodontal tissue regeneration by combined implantation of adipose tissue-derived stem cells and platelet-rich plasma in a canine model.

PubMed

Tobita, Morikuni; Uysal, Cagri A; Guo, Xin; Hyakusoku, Hiko; Mizuno, Hiroshi

2013-12-01

One goal of periodontal therapy is to regenerate periodontal tissues. Stem cells, growth factors and scaffolds and biomaterials are vital for the restoration of the architecture and function of complex tissues. Adipose tissue-derived stem cells (ASCs) are an ideal population of stem cells for practical regenerative medicine. In addition, platelet-rich plasma (PRP) can be useful for its ability to stimulate tissue regeneration. PRP contains various growth factors and may be useful as a cell carrier in stem cell therapies. The purpose of this study was to determine whether a mixture of ASCs and PRP promoted periodontal tissue regeneration in a canine model. Autologous ASCs and PRP were implanted into areas with periodontal tissue defects. Periodontal tissue defects that received PRP alone or non-implantation were also examined. Histologic, immunohistologic and x-ray studies were performed 1 or 2 months after implantation. The amount of newly formed bone and the scale of newly formed cementum in the region of the periodontal tissue defect were analyzed on tissue sections. The areas of newly formed bone and cementum were greater 2 months after implantation of ASCs and PRP than at 1 month after implantation, and the radiopacity in the region of the periodontal tissue defect increased markedly by 2 months after implantation. The ASCs and PRP group exhibited periodontal tissue with the correct architecture, including alveolar bone, cementum-like structures and periodontal ligament-like structures, by 2 months after implantation. These findings suggest that a combination of autologous ASCs and PRP promotes periodontal tissue regeneration that develops the appropriate architecture for this complex tissue. Copyright © 2013 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

Central Cemento-Ossifying Fibroma: Primary Odontogenic or Osseous Neoplasm?

PubMed

Woo, Sook-Bin

2015-12-01

Currently, central cemento-ossifying fibroma is classified by the World Health Organization as a primary bone-forming tumor of the jaws. However, histopathologically, it is often indistinguishable from cemento-osseous dysplasias in that it forms osteoid and cementicles (cementum droplets) in varying proportions. It is believed that pluripotent cells within the periodontal membrane can be stimulated to produce either osteoid or woven bone and cementicles when stimulated. If this is true, cemento-ossifying fibroma would be better classified as a primary odontogenic neoplasm arising from the periodontal ligament. Cemento-ossifying fibromas also do not occur in the long bones. The present report compares several entities that fall within the diagnostic realm of benign fibro-osseous lesions and reviews the evidence for reclassifying central cemento-ossifying fibroma as a primary odontogenic neoplasm. Copyright © 2015 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Experimental stimulation of bone healing with teriparatide: histomorphometric and microhardness analysis in a mouse model of closed fracture.

PubMed

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.

Self-demodulation of amplitude-modulated signal components in amplitude-modulated bone-conducted ultrasonic hearing

NASA Astrophysics Data System (ADS)

Ito, Kazuhito; Nakagawa, Seiji

2015-07-01

A novel hearing aid system utilizing amplitude-modulated bone-conducted ultrasound (AM-BCU) is being developed for use by profoundly deaf people. However, there is a lack of research on the acoustic aspects of AM-BCU hearing. In this study, acoustic fields in the ear canal under AM-BCU stimulation were examined with respect to the self-demodulation effect of amplitude-modulated signal components generated in the ear canal. We found self-demodulated signals with an audible sound pressure level related to the amplitude-modulated signal components of bone-conducted ultrasonic stimulation. In addition, the increases in the self-demodulated signal levels at low frequencies in the ear canal after occluding the ear canal opening, i.e., the positive occlusion effect, indicate the existence of a pathway by which the self-demodulated signals pass through the aural cartilage and soft tissue, and radiate into the ear canal.

Effects of new sports tennis type exercise on aerobic capacity, follicle stimulating hormone and N-terminal telopeptide in the postmenopausal women.

PubMed

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.

Reduced functional loads alter the physical characteristics of the bone-PDL-cementum complex

PubMed Central

Niver, Eric L.; Leong, Narita; Greene, Janelle; Curtis, Donald; Ryder, Mark I.; Ho, Sunita P.

2011-01-01

Background Adaptive properties of the bone-PDL-tooth complex have been identified by changing the magnitude of functional loads using small-scale animal models such as rodents. Reported adaptive responses as a result of lower loads due to softer diet include decreased muscle development, change in structure-function relationship of the cranium, narrowed PDL-space, changes in mineral level of the cortical bone and alveolar jaw bone, and glycosaminoglycans of the alveolar bone. However, the adaptive role of the dynamic bone-PDL-cementum complex due to prolonged reduced loads has not been fully explained to date, especially with regards to concurrent adaptations of bone, PDL and cementum. Hence, the temporal effect of reduced functional loads on physical characteristics such as morphology and mechanical properties, and mineral profiles of the bone-periodontal ligament (PDL)-cementum complex using a rat model was investigated. Materials and Methods Two groups of six-week-old male Sprague-Dawley rats were fed nutritionally identical food with a stiffness range of 127–158N/mm for hard pellet or 0.32–0.47N/mm for soft powder forms. Spatio-temporal adaptation of the bone-PDL-cementum complex was identified by mapping changes in: 1) PDL-collagen orientation and birefringence using polarized light microscopy, bone and cementum adaptation using histochemistry, and bone and cementum morphology using micro X-ray computed tomography, 2) mineral profiles of the PDL-cementum and PDL-bone interfaces by X-ray attenuation, and 3) microhardness of bone and cementum by microindentation of specimens at ages six, eight, twelve, and fifteen weeks. Results Reduced functional loads over prolonged time resulted in 1) altered PDL orientation and decreased PDL collagen birefringence indicating decreased PDL turnover rate and decreased apical cementum resorption; 2) a gradual increase in X-ray attenuation, owing to mineral differences, at the PDL-bone and PDL-cementum interfaces without significant differences in the gradients for either group; 3) significantly (p<0.05) lower microhardness of alveolar bone (0.93±0.16 GPa) and secondary cementum (0.803±0.13 GPa) compared to the higher load group (1.10±0.17 GPa and 0.940±0.15 GPa respectively) at fifteen weeks indicating a temporal effect of loads on local mineralization of bone and cementum. Conclusions Based on the results from this study, the effect of reduced functional loads for a prolonged time could differentially affect morphology and mechanical properties, and mineral variations and of the local load-bearing sites in a bone-PDL-cementum complex. These observed local changes in turn could help explain the overall biomechanical function and adaptations of the tooth-bone joint. From a clinical translation perspective, our study provides an insight into modulation of load on the complex for improved tooth function during periodontal disease, and/or orthodontic and prosthodontic treatments. PMID:21848615

Effects of dietary Aspergillus meal prebiotic on turkey poults production parameters and bone qualities

USDA-ARS?s Scientific Manuscript database

The objective of this study was to evaluate the effects of dietary Aspergillus meal (AM), a prebiotic on performance and bone parameters of neonatal turkey poults. Prebiotics are nondigestible food ingredients that beneficially affect the host and have been shown to stimulate calcium and magnesium a...

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

A Surgical Procedure for Resecting the Mouse Rib: A Model for Large-Scale Long Bone Repair

PubMed Central

Funnell, John W.; Thein, Thu Zan Tun; Mariani, Francesca V.

2015-01-01

This protocol introduces researchers to a new model for large-scale bone repair utilizing the mouse rib. The procedure details the following: preparation of the animal for surgery, opening the thoracic body wall, exposing the desired rib from the surrounding intercostal muscles, excising the desired section of rib without inducing a pneumothorax, and closing the incisions. Compared to the bones of the appendicular skeleton, the ribs are highly accessible. In addition, no internal or external fixator is necessary since the adjacent ribs provide a natural fixation. The surgery uses commercially available supplies, is straightforward to learn, and well-tolerated by the animal. The procedure can be carried out with or without removing the surrounding periosteum, and therefore the contribution of the periosteum to repair can be assessed. Results indicate that if the periosteum is retained, robust repair occurs in 1 - 2 months. We expect that use of this protocol will stimulate research into rib repair and that the findings will facilitate the development of new ways to stimulate bone repair in other locations around the body. PMID:25651082

Use of Nandrolone Decanoate in Treatment of Pure Red Cell Aplasia Secondary to Diclofenac Administration: A Case Report.

PubMed

de Marchi, Paula Nassar; Sueur Vieira, André Nanny Le; Antunes Ribeiro, José Francisco; Geraldes, Silvano Salgueiro; Rodrigues Ramos, Paulo Roberto; Melchert, Alessandra; Guimarães-Okamoto, Priscylla Tatiana Chalfun

2017-03-01

Pure red cell aplasia (PRCA) is a disorder that leads to a nonregenerative anemia that results from erythroid precursors failing to reach maturity in the bone marrow, whereas the numbers of mature myeloid and megakaryocytic cells remain normal. PRCA can be induced by autoimmune processes, infections, drugs, toxins, and radiation, and is diagnosed by a bone marrow cytology examination after excluding the most common causes of nonregenerative anemia. Immunosuppressive therapies are used to treat PRCA, and usually involve the use of glucocorticoids, cyclosporin, or azathioprine. Alternatively, although little studied in veterinary medicine, drugs which stimulate bone marrow (e.g., nandrolone decanoate) have been mentioned as possible therapeutic agents. A case of PRCA that presented at the Veterinary Teaching Hospital of the Faculty of Veterinary Medicine and Animal Science (UNESP)-Botucatu, Brazil showed a good therapeutic response to weekly administration of nandrolone decanoate. Therefore, it was concluded that bone marrow stimulants might improve the quality of life of PRCA patients, provided they are used with caution and under close clinical supervision. Copyright © 2017 Elsevier Inc. All rights reserved.

Morphological and histochemical studies of bone and cartilage during periods of stimulated weightlessness

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.

Vertical bone growth following autotransplantation of the developing maxillary third molar to replace a retained mandibular permanent molar: a case report.

PubMed

Plakwicz, Paweł; Czochrowska, Ewa Monika; Milczarek, Anna; Zadurska, Malgorzata

2014-01-01

A retained permanent mandibular first molar caused arrested development and a defect of the alveolar bone in a 16-year-old girl. Extraction of the ankylosed tooth was immediately followed by autotransplantation of the developing maxillary third molar. At the 3-year follow-up examination the interproximal bone level at the autotransplanted molar was equal to that of the neighboring teeth. Cone beam computed tomography showed bone at the labial aspect of the transplant. The eruption of the autotransplanted tooth stimulated vertical alveolar bone development and repaired the bone defect. Additionally, there was closure of the posterior open bite that was initially present at the ankylosed molar site.

Spaceflight-induced Bone Loss: Is there a Risk for Accelerated Osteoporosis after Return?

NASA Technical Reports Server (NTRS)

Sibonga, Jean

2008-01-01

The evidence-to to-date suggests that the rapid rate of site-specific bone loss in space, due to the unbalanced stimulation of bone resorption, may predispose crew members to irreversible changes in bone structure and microarchitecture. No analyses conducted in the postflight period to assess microarchitectural changes. There is no complete analysis of skeletal recovery in the postflight period to evaluate the structural changes that accompany increases in DXA aBMD. Postflight analyses based upon QCT scans performed on limited crew members indicate reductions in hip bone strength and incomplete recovery at 1 year. No recovery of trabecular vBMD after 1 year return (HRP IWG). Time course of bone loss in space unknown.

21 CFR 73.3110 - Chlorophyllin-copper complex, oil soluble.

Code of Federal Regulations, 2010 CFR

2010-04-01

... oil, peanut oil, and hydrogenated peanut oil), may be safely used to color polymethylmethacrylate bone... the bone cement. (2) Authorization for this use shall not be construed as waiving any of the... the polymethylmethacrylate bone cement in which chlorophyllin-copper complex, oil soluble, is used. (d...

21 CFR 73.3110 - Chlorophyllin-copper complex, oil soluble.

Code of Federal Regulations, 2013 CFR

2013-04-01

... oil, peanut oil, and hydrogenated peanut oil), may be safely used to color polymethylmethacrylate bone... the bone cement. (2) Authorization for this use shall not be construed as waiving any of the... the polymethylmethacrylate bone cement in which chlorophyllin-copper complex, oil soluble, is used. (d...

21 CFR 73.3110 - Chlorophyllin-copper complex, oil soluble.

Code of Federal Regulations, 2014 CFR

2014-04-01

... oil, peanut oil, and hydrogenated peanut oil), may be safely used to color polymethylmethacrylate bone... the bone cement. (2) Authorization for this use shall not be construed as waiving any of the... the polymethylmethacrylate bone cement in which chlorophyllin-copper complex, oil soluble, is used. (d...

21 CFR 73.3110 - Chlorophyllin-copper complex, oil soluble.

Code of Federal Regulations, 2012 CFR

2012-04-01

... oil, peanut oil, and hydrogenated peanut oil), may be safely used to color polymethylmethacrylate bone... the bone cement. (2) Authorization for this use shall not be construed as waiving any of the... the polymethylmethacrylate bone cement in which chlorophyllin-copper complex, oil soluble, is used. (d...

21 CFR 73.3110 - Chlorophyllin-copper complex, oil soluble.

Code of Federal Regulations, 2011 CFR

2011-04-01

... oil, peanut oil, and hydrogenated peanut oil), may be safely used to color polymethylmethacrylate bone... the bone cement. (2) Authorization for this use shall not be construed as waiving any of the... the polymethylmethacrylate bone cement in which chlorophyllin-copper complex, oil soluble, is used. (d...

Kidney tubular-cell secretion of osteoblast growth factor is increased by kaempferol: a scientific basis for "the kidney controlling the bone" theory of Chinese medicine.

PubMed

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.

Electroacupuncture stimulation at CV4 prevents ovariectomy-induced osteoporosis in rats via Wnt-β-catenin signaling.

PubMed

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.

Electroacupuncture stimulation at CV4 prevents ovariectomy-induced osteoporosis in rats via Wnt-β-catenin signaling

PubMed Central

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

Spontaneous Differentiation of Human Mesenchymal Stem Cells on Poly-Lactic-Co-Glycolic Acid Nano-Fiber Scaffold.

PubMed

Sonomoto, Koshiro; Yamaoka, Kunihiro; Kaneko, Hiroaki; Yamagata, Kaoru; Sakata, Kei; Zhang, Xiangmei; Kondo, Masahiro; Zenke, Yukichi; Sabanai, Ken; Nakayamada, Shingo; Sakai, Akinori; Tanaka, Yoshiya

2016-01-01

Mesenchymal stem cells (MSCs) have immunosuppressive activity and can differentiate into bone and cartilage; and thus seem ideal for treatment of rheumatoid arthritis (RA). Here, we investigated the osteogenesis and chondrogenesis potentials of MSCs seeded onto nano-fiber scaffolds (NFs) in vitro and possible use for the repair of RA-affected joints. MSCs derived from healthy donors and patients with RA or osteoarthritis (OA) were seeded on poly-lactic-glycolic acid (PLGA) electrospun NFs and cultured in vitro. Healthy donor-derived MSCs seeded onto NFs stained positive with von Kossa at Day 14 post-stimulation for osteoblast differentiation. Similarly, MSCs stained positive with Safranin O at Day 14 post-stimulation for chondrocyte differentiation. Surprisingly, even cultured without any stimulation, MSCs expressed RUNX2 and SOX9 (master regulators of bone and cartilage differentiation) at Day 7. Moreover, MSCs stained positive for osteocalcin, a bone marker, and simultaneously also with Safranin O at Day 14. On Day 28, the cell morphology changed from a spindle-like to an osteocyte-like appearance with processes, along with the expression of dentin matrix protein-1 (DMP-1) and matrix extracellular phosphoglycoprotein (MEPE), suggesting possible differentiation of MSCs into osteocytes. Calcification was observed on Day 56. Expression of osteoblast and chondrocyte differentiation markers was also noted in MSCs derived from RA or OA patients seeded on NFs. Lactic acid present in NFs potentially induced MSC differentiation into osteoblasts. Our PLGA scaffold NFs induced MSC differentiation into bone and cartilage. NFs induction process resembled the procedure of endochondral ossification. This finding indicates that the combination of MSCs and NFs is a promising therapeutic technique for the repair of RA or OA joints affected by bone and cartilage destruction.

Extracellular vesicles released from mesenchymal stromal cells stimulate bone growth in osteogenesis imperfecta.

PubMed

Otsuru, Satoru; Desbourdes, Laura; Guess, Adam J; Hofmann, Ted J; Relation, Theresa; Kaito, Takashi; Dominici, Massimo; Iwamoto, Masahiro; Horwitz, Edwin M

2018-01-01

Systemic infusion of mesenchymal stromal cells (MSCs) has been shown to induce acute acceleration of growth velocity in children with osteogenesis imperfecta (OI) despite minimal engraftment of infused MSCs in bones. Using an animal model of OI we have previously shown that MSC infusion stimulates chondrocyte proliferation in the growth plate and that this enhanced proliferation is also observed with infusion of MSC conditioned medium in lieu of MSCs, suggesting that bone growth is due to trophic effects of MSCs. Here we sought to identify the trophic factor secreted by MSCs that mediates this therapeutic activity. To examine whether extracellular vesicles (EVs) released from MSCs have therapeutic activity, EVs were isolated from MSC conditioned medium by ultracentrifugation. To further characterize the trophic factor, RNA or microRNA (miRNA) within EVs was depleted by either ribonuclease (RNase) treatment or suppressing miRNA biogenesis in MSCs. The functional activity of these modified EVs was evaluated using an in vitro chondrocyte proliferation assay. Finally, bone growth was evaluated in an animal model of OI treated with EVs. We found that infusion of MSC-derived EVs stimulated chondrocyte proliferation in the growth plate, resulting in improved bone growth in a mouse model of OI. However, infusion of neither RNase-treated EVs nor miRNA-depleted EVs enhanced chondrocyte proliferation. MSCs exert therapeutic effects in OI by secreting EVs containing miRNA, and EV therapy has the potential to become a novel cell-free therapy for OI that will overcome some of the current limitations in MSC therapy. Copyright © 2017 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

Effects of microstructure and water on the electrical potentials in bone induced by ultrasound irradiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsuneda, H.; Matsukawa, S.; Takayanagi, S.

The healing mechanism of bone fractures by low intensity pulse ultrasound is yet to be fully understood. There have been many discussions regarding how the high frequency dynamic stress can stimulate numerous cell types through various pathways. As one possible initial process of this mechanism, we focus on the piezoelectricity of bone and demonstrate that bone can generate electrical potentials by ultrasound irradiation in the MHz range. We have fabricated ultrasonic bone transducers using bovine cortical bone as the piezoelectric device. The ultrasonically induced electrical potentials in the transducers change as a function of time during immersed ultrasonic pulse measurementsmore » and become stable when the bone is fully wet. In addition, the magnitude of the induced electrical potentials changes owing to the microstructure in the cortical bone. The potentials of transducers with haversian structure bone are higher than those of plexiform structure bone, which informs about the effects of bone microstructure on the piezoelectricity.« less

Effects of microstructure and water on the electrical potentials in bone induced by ultrasound irradiation

NASA Astrophysics Data System (ADS)

Tsuneda, H.; Matsukawa, S.; Takayanagi, S.; Mizuno, K.; Yanagitani, T.; Matsukawa, M.

2015-02-01

The healing mechanism of bone fractures by low intensity pulse ultrasound is yet to be fully understood. There have been many discussions regarding how the high frequency dynamic stress can stimulate numerous cell types through various pathways. As one possible initial process of this mechanism, we focus on the piezoelectricity of bone and demonstrate that bone can generate electrical potentials by ultrasound irradiation in the MHz range. We have fabricated ultrasonic bone transducers using bovine cortical bone as the piezoelectric device. The ultrasonically induced electrical potentials in the transducers change as a function of time during immersed ultrasonic pulse measurements and become stable when the bone is fully wet. In addition, the magnitude of the induced electrical potentials changes owing to the microstructure in the cortical bone. The potentials of transducers with haversian structure bone are higher than those of plexiform structure bone, which informs about the effects of bone microstructure on the piezoelectricity.

Stimulation of liver IGF-1 expression promotes peak bone mass achievement in growing rats: a study with pomegranate seed oil.

PubMed

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.

Differential Effects of Teriparatide and Denosumab on Intact PTH and Bone Formation Indices: AVA Osteoporosis Study

PubMed Central

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

Intravenous bisphosphonate-related osteonecrosis of the jaws: Influence of coadjuvant antineoplastic treatment and study of buccodental condition

PubMed Central

Bagán, José; Poveda-Roda, Rafael

2013-01-01

Objectives: To determine whether coadjuvant antineoplastic treatment can influence the number and size of bone exposures among patients with intravenous bisphosphonate-related osteonecrosis of the jaws (iBRONJ), and to analyze the buccodental condition of these patients. Material and methods: The study sample comprised 67 patients with iBRONJ, 53 patients without iBRONJ receiving treatment with intravenous bisphosphonates, and 36 healthy subjects. In all three groups, measurements were made of the CAO index and of resting whole saliva and stimulated whole saliva. In the patients with iBRONJ, the size (cm) and number of bone exposures were recorded. The data obtained were subjected to analysis of variance (ANOVA), the Mann-Whitney U-test, and multivariate logistic regression analysis. Results: A total of 57.6% of the patients presented single bone exposure, 25.4% presented two, and 17% more than two exposures. The mean exposure size was 2.3±1.9 cm. Neither the bivariate analysis nor the multivariate multiple regression analysis found coadjuvant antineoplastic treatment to exert a statistically significant effect upon the number and size of bone exposures. On the other hand, there were statistically significant differences among the three study groups in relation to the CAO index (p=0.02) and the number of missing teeth (p=0.00). The resting whole saliva and stimulated whole saliva levels were similar in the three groups, though the patients with osteonecrosis of the jaws showed comparatively lower SWS levels. Conclusions: Coadjuvant antineoplastic treatment alone appears to exert no influence upon the size and number of bone exposures in iBRONJ. The patients with this disease show a higher CAO index and a larger number of missing teeth. Key words:Osteonecrosis of the jaws, bisphosphonates, bone exposure, CAO index, resting whole saliva, stimulated whole saliva. PMID:23229272

Mouse osteoblastic cell line (MC3T3-E1) expresses extracellular calcium (Ca2+o)-sensing receptor and its agonists stimulate chemotaxis and proliferation of MC3T3-E1 cells

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.

Short-term Low-strain Vibration Enhances Chemo-transport Yet Does Not Stimulate Osteogenic Gene Expression or Cortical Bone Formation in Adult Mice

PubMed Central

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

Low-intensity pulsed ultrasound stimulation promotes osteoblast differentiation through hedgehog signaling.

PubMed

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.

Low Oxygen Modulates Multiple Signaling Pathways, Increasing Self-Renewal, While Decreasing Differentiation, Senescence, and Apoptosis in Stromal MIAMI Cells

PubMed Central

Rios, Carmen; D'Ippolito, Gianluca; Curtis, Kevin M.; Delcroix, Gaëtan J.-R.; Gomez, Lourdes A.; El Hokayem, Jimmy; Rieger, Megan; Parrondo, Ricardo; de las Pozas, Alicia; Perez-Stable, Carlos; Howard, Guy A.

2016-01-01

Human bone marrow multipotent mesenchymal stromal cell (hMSC) number decreases with aging. Subpopulations of hMSCs can differentiate into cells found in bone, vasculature, cartilage, gut, and other tissues and participate in their repair. Maintaining throughout adult life such cell subpopulations should help prevent or delay the onset of age-related degenerative conditions. Low oxygen tension, the physiological environment in progenitor cell-rich regions of the bone marrow microarchitecture, stimulates the self-renewal of marrow-isolated adult multilineage inducible (MIAMI) cells and expression of Sox2, Nanog, Oct4a nuclear accumulation, Notch intracellular domain, notch target genes, neuronal transcriptional repressor element 1 (RE1)-silencing transcription factor (REST), and hypoxia-inducible factor-1 alpha (HIF-1α), and additionally, by decreasing the expression of (i) the proapoptotic proteins, apoptosis-inducing factor (AIF) and Bak, and (ii) senescence-associated p53 expression and β-galactosidase activity. Furthermore, low oxygen increases canonical Wnt pathway signaling coreceptor Lrp5 expression, and PI3K/Akt pathway activation. Lrp5 inhibition decreases self-renewal marker Sox2 mRNA, Oct4a nuclear accumulation, and cell numbers. Wortmannin-mediated PI3K/Akt pathway inhibition leads to increased osteoblastic differentiation at both low and high oxygen tension. We demonstrate that low oxygen stimulates a complex signaling network involving PI3K/Akt, Notch, and canonical Wnt pathways, which mediate the observed increase in nuclear Oct4a and REST, with simultaneous decrease in p53, AIF, and Bak. Collectively, these pathway activations contribute to increased self-renewal with concomitant decreased differentiation, cell cycle arrest, apoptosis, and/or senescence in MIAMI cells. Importantly, the PI3K/Akt pathway plays a central mechanistic role in the oxygen tension-regulated self-renewal versus osteoblastic differentiation of progenitor cells. PMID:27059084

Hydrostatic pressure in combination with topographical cues affects the fate of bone marrow-derived human mesenchymal stem cells for bone tissue regeneration.

PubMed

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.

Hydrostatic pressure in combination with topographical cues affects the fate of bone marrow‐derived human mesenchymal stem cells for bone tissue regeneration

PubMed Central

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

Reduced functional loads alter the physical characteristics of the bone-periodontal ligament-cementum complex.

PubMed

Niver, E L; Leong, N; Greene, J; Curtis, D; Ryder, M I; Ho, S P

2011-12-01

Adaptive properties of the bone-periodontal ligament-tooth complex have been identified by changing the magnitude of functional loads using small-scale animal models, such as rodents. Reported adaptive responses as a result of lower loads due to softer diet include decreased muscle development, change in structure-function relationship of the cranium, narrowed periodontal ligament space, and changes in the mineral level of the cortical bone and alveolar jaw bone and in the glycosaminoglycans of the alveolar bone. However, the adaptive role of the dynamic bone-periodontal ligament-cementum complex to prolonged reduced loads has not been fully explained to date, especially with regard to concurrent adaptations of bone, periodontal ligament and cementum. Therefore, in the present study, using a rat model, the temporal effect of reduced functional loads on physical characteristics, such as morphology and mechanical properties and the mineral profiles of the bone-periodontal ligament-cementum complex was investigated. Two groups of 6-wk-old male Sprague-Dawley rats were fed nutritionally identical food with a stiffness range of 127-158 N/mm for hard pellet or 0.3-0.5 N/mm for soft powder forms. Spatio-temporal adaptation of the bone-periodontal ligament-cementum complex was identified by mapping changes in the following: (i) periodontal ligament collagen orientation and birefringence using polarized light microscopy, bone and cementum adaptation using histochemistry, and bone and cementum morphology using micro-X-ray computed tomography; (ii) mineral profiles of the periodontal ligament-cementum and periodontal ligament-bone interfaces by X-ray attenuation; and (iii) microhardness of bone and cementum by microindentation of specimens at ages 6, 8, 12 and 15 wk. Reduced functional loads over prolonged time resulted in the following adaptations: (i) altered periodontal ligament orientation and decreased periodontal ligament collagen birefringence, indicating decreased periodontal ligament turnover rate and decreased apical cementum resorption; (ii) a gradual increase in X-ray attenuation, owing to mineral differences, at the periodontal ligament-bone and periodontal ligament-cementum interfaces, without significant differences in the gradients for either group; (iii) significantly (p < 0.05) lower microhardness of alveolar bone (0.93 ± 0.16 GPa) and secondary cementum (0.803 ± 0.13 GPa) compared with the higher load group insert bone = (1.10 ± 0.17 and cementum = 0.940 ± 0.15 GPa, respectively) at 15 wk, indicating a temporal effect of loads on the local mineralization of bone and cementum. Based on the results from this study, the effect of reduced functional loads for a prolonged time could differentially affect morphology, mechanical properties and mineral variations of the local load-bearing sites in the bone-periodontal ligament-cementum complex. These observed local changes in turn could help to explain the overall biomechanical function and adaptations of the tooth-bone joint. From a clinical translation perspective, our study provides an insight into modulation of load on the complex for improved tooth function during periodontal disease and/or orthodontic and prosthodontic treatments. © 2011 John Wiley & Sons A/S.

Stimulation of interleukin-6 production of periodontal ligament cells by Porphyromonas endodontalis lipopolysaccharide.

PubMed

Ogura, N; Shibata, Y; Kamino, Y; Matsuda, U; Hayakawa, M; Oikawa, T; Takiguchi, H; Izumi, H; Abiko, Y

1994-12-01

Interleukin-6 (IL-6), which is a multifunctional cytokine, has important roles in acute and chronic inflammation and may also be implicated in bone resorption. We examined the IL-6 production in periodontal ligament (PDL) cells which were treated with lipopolysaccharide (LPS) from several oral inflammatory pathogens. The LPS from Porphyromonas endodontalis, which was isolated from infected root canals and radicular cyst fluids, was more potent than the LPS from any other periodontal organisms examined. P. endodontalis LPS stimulated IL-6 release from PDL cells in a time- and dose-dependent manner. Northern blot hybridization analysis revealed that the IL-6 mRNA level in PDL cells was increased by P. endodontalis LPS. These results suggest that stimulation of the IL-6 release of PDL cells by P. endodontalis LPS may have a role in the progression of inflammation and alveolar bone resorption in periodontal and periapical diseases.

Enhanced osteointegration of poly(methylmethacrylate) bone cements by incorporating strontium-containing borate bioactive glass

PubMed Central

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

The effects of vibration loading on adipose stem cell number, viability and differentiation towards bone-forming cells

PubMed Central

Tirkkonen, Laura; Halonen, Heidi; Hyttinen, Jari; Kuokkanen, Hannu; Sievänen, Harri; Koivisto, Anna-Maija; Mannerström, Bettina; Sándor, George K. B.; Suuronen, Riitta; Miettinen, Susanna; Haimi, Suvi

2011-01-01

Mechanical stimulation is an essential factor affecting the metabolism of bone cells and their precursors. We hypothesized that vibration loading would stimulate differentiation of human adipose stem cells (hASCs) towards bone-forming cells and simultaneously inhibit differentiation towards fat tissue. We developed a vibration-loading device that produces 3g peak acceleration at frequencies of 50 and 100 Hz to cells cultured on well plates. hASCs were cultured using either basal medium (BM), osteogenic medium (OM) or adipogenic medium (AM), and subjected to vibration loading for 3 h d–1 for 1, 7 and 14 day. Osteogenesis, i.e. differentiation of hASCs towards bone-forming cells, was analysed using markers such as alkaline phosphatase (ALP) activity, collagen production and mineralization. Both 50 and 100 Hz vibration frequencies induced significantly increased ALP activity and collagen production of hASCs compared with the static control at 14 day in OM. A similar trend was detected for mineralization, but the increase was not statistically significant. Furthermore, vibration loading inhibited adipocyte differentiation of hASCs. Vibration did not affect cell number or viability. These findings suggest that osteogenic culture conditions amplify the stimulatory effect of vibration loading on differentiation of hASCs towards bone-forming cells. PMID:21613288

Enhanced osteointegration of poly(methylmethacrylate) bone cements by incorporating strontium-containing borate bioactive glass.

PubMed

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).

Bone mineral as an electrical energy reservoir.

PubMed

Nakamura, Miho; Hiratai, Rumi; Yamashita, Kimihiro

2012-05-01

Mechanical stress in bone induces an electrical potential generated by piezoelectricity arising from displacement of collagen fibrils. Where and for how long the potential is stored in bone; however, are still poorly understood. We investigated the electrical properties of collagen fibrils and apatite minerals and found that bone, when polarized electrically by applying an external voltage, depolarizes by two mechanisms. Plots of thermally stimulated depolarization current show two significant peaks: one at 100°C, attributed to collagen fibrils because decalcified bone exhibits depolarization peak at 100°C, and the other at 500°C, attributed to apatite minerals because calcined bone exhibits depolarization peak at 500°C and has activation energy similar to that for synthesized apatite. The crystallographic c-axis orientation of calcined bone depends on the direction in which the bone is cut, either transverse or longitudinal, and strongly affects the polarization efficacy. Copyright © 2012 Wiley Periodicals, Inc.

Leptin: a potential mediator for protective effects of fat mass on bone tissue.

PubMed

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.

Harnessing and Modulating Inflammation in Strategies for Bone Regeneration

PubMed Central

Mountziaris, Paschalia M.; Spicer, Patrick P.; Kasper, F. Kurtis

2011-01-01

Inflammation is an immediate response that plays a critical role in healing after fracture or injury to bone. However, in certain clinical contexts, such as in inflammatory diseases or in response to the implantation of a biomedical device, the inflammatory response may become chronic and result in destructive catabolic effects on the bone tissue. Since our previous review 3 years ago, which identified inflammatory signals critical for bone regeneration and described the inhibitory effects of anti-inflammatory agents on bone healing, a multitude of studies have been published exploring various aspects of this emerging field. In this review, we distinguish between regenerative and damaging inflammatory processes in bone, update our discussion of the effects of anti-inflammatory agents on bone healing, summarize recent in vitro and in vivo studies demonstrating how inflammation can be modulated to stimulate bone regeneration, and identify key future directions in the field. PMID:21615330

Physical activity in the prevention and amelioration of osteoporosis in women : interaction of mechanical, hormonal and dietary factors.

PubMed

Borer, Katarina T

2005-01-01

Osteoporosis is a serious health problem that diminishes quality of life and levies a financial burden on those who fear and experience bone fractures. Physical activity as a way to prevent osteoporosis is based on evidence that it can regulate bone maintenance and stimulate bone formation including the accumulation of mineral, in addition to strengthening muscles, improving balance, and thus reducing the overall risk of falls and fractures. Currently, our understanding of how to use exercise effectively in the prevention of osteoporosis is incomplete. It is uncertain whether exercise will help accumulate more overall peak bone mass during childhood, adolescence and young adulthood. Also, the consistent effectiveness of exercise to increase bone mass, or at least arrest the loss of bone mass after menopause, is also in question. Within this framework, section 1 introduces mechanical characteristics of bones to assist the reader in understanding their responses to physical activity. Section 2 reviews hormonal, nutritional and mechanical factors necessary for the growth of bones in length, width and mineral content that produce peak bone mass in the course of childhood and adolescence using a large sample of healthy Caucasian girls and female adolescents for reference. Effectiveness of exercise is evaluated throughout using absolute changes in bone with the underlying assumption that useful exercise should produce changes that approximate or exceed the absolute magnitude of bone parameters in a healthy reference population. Physical activity increases growth in width and mineral content of bones in girls and adolescent females, particularly when it is initiated before puberty, carried out in volumes and at intensities seen in athletes, and accompanied by adequate caloric and calcium intakes. Similar increases are seen in young women following the termination of statural growth in response to athletic training, but not to more limited levels of physical activity characteristic of longitudinal training studies. After 9-12 months of regular exercise, young adult women often show very small benefits to bone health, possibly because of large subject attrition rates, inadequate exercise intensity, duration or frequency, or because at this stage of life accumulation of bone mass may be at its natural peak. The important influence of hormones as well as dietary and specific nutrient abundance on bone growth and health are emphasised, and premature bone loss associated with dietary restriction and estradiol withdrawal in exercise-induced amenorrhoea is described. In section 3, the same assessment is applied to the effects of physical activity in postmenopausal women. Studies of postmenopausal women are presented from the perspective of limitations of the capacity of the skeleton to adapt to mechanical stress of exercise due to altered hormonal status and inadequate intake of specific nutrients. After menopause, effectiveness of exercise to increase bone mineral depends heavily on adequate availability of dietary calcium. Relatively infrequent evidence that physical activity prevents bone loss or increases bone mineral after menopause may be a consequence of inadequate calcium availability or low intensity of exercise in training studies. Several studies with postmenopausal women show modest increases in bone mineral toward the norm seen in a healthy population in response to high-intensity training. Physical activities continue to stimulate increases in bone diameter throughout the lifespan. These exercise-stimulated increases in bone diameter diminish the risk of fractures by mechanically counteracting the thinning of bones and increases in bone porosity. Seven principles of bone adaptation to mechanical stress are reviewed in section 4 to suggest how exercise by human subjects could be made more effective. They posit that exercise should: (i) be dynamic, not static; (ii) exceed a threshold intensity; (iii) exceed a threshold strain frequency; (iv) be relatively brief but intermittent; (v) impose an unusual loading pattern on the bones; (vi) be supported by unlimited nutrient energy; and (vii) include adequate calcium and cholecalciferol (vitamin D3) availability.

Sclerostin and Dickkopf-1 as therapeutic targets in bone diseases.

PubMed

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.

Intramuscular Transplantation and Survival of Freshly Isolated Bone Marrow Cells following Skeletal Muscle Ischemia-reperfusion Injury

DTIC Science & Technology

2013-01-01

2) in a rat I/R model, consis- tent with this time course of functional recovery, evidence of muscle fiber damage and regeneration was still present...Contractile function of the anterior crural muscles was assessed by measuring maximal isometric torque as a function of stimulation frequency (20Y200 Hz...from the direct conver- sion of bone marrowYderived cells to muscle fibers , the paracrine secretory effects of stem cells resident in bone marrow

Combination of hindlimb suspension and immobilization by casting exaggerates sarcopenia by stimulating autophagy but does not worsen osteopenia.

PubMed

Speacht, Toni L; Krause, Andrew R; Steiner, Jennifer L; Lang, Charles H; Donahue, Henry J

2018-05-01

Astronauts in space experience a unique environment that causes the concomitant loss of bone and muscle. However, the interaction between these tissues and how osteopenia and sarcopenia affect each other is unclear. We explored this relationship by exaggerating unloading-induced muscle loss using a unilateral casting model in conjunction with hindlimb suspension (HLS). Five-month-old, male C57Bl/6J mice subjected to HLS for 2 weeks displayed a significant decrease in gastrocnemius and quadriceps weight (-9-10%), with a two-fold greater decrease in muscle mass observed in the HLS + casted limb. However, muscle from casted limbs had a higher rate of protein synthesis (+16%), compared to HLS alone, with coordinated increases in S6K1 (+50%) and 4E-BP1 (+110%) phosphorylation. Increased protein content for surrogate markers of autophagy, including LC3-II (+75%), Atg7 (+10%), and Atg5-12 complex (+20%) was only detected in muscle from the casted limb. In proximal tibias, HLS resulted in significant decreases in bone volume fraction (-24% vs -8%), trabecular number (-6% vs +0.3%), trabecular thickness (-10% vs -2%), and trabecular spacing (+8.4% vs +2%) compared to ground controls. There was no further bone loss in casted limbs compared to HLS alone. In tibia midshafts, HLS resulted in decreased total area (-2% vs +1%) and increased bone mineral density (+1% vs -0.3%) compared to ground controls. Cortical bone from casted limbs showed an increase in cortical thickness (+9% vs +2%) and cortical area/total area (+1% vs -0.6%) compared to HLS alone. Our results suggest that casting exacerbates unloading-induced muscle loss via activation of autophagy. Casting did not exacerbate bone loss suggesting that the unloading-induced loss of muscle and bone can be temporally dissociated and the effect of reduced muscle activity plays a relatively minor role compared to reduced load bearing on trabecular bone structure. Copyright © 2018 Elsevier Inc. All rights reserved.

[Osteoporosis treatment in patients with hyperthyroidism].

PubMed

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.

Abnormal XPD-induced nuclear receptor transactivation in DNA repair disorders: trichothiodystrophy and xeroderma pigmentosum

PubMed Central

Zhou, Xiaolong; Khan, Sikandar G; Tamura, Deborah; Ueda, Takahiro; Boyle, Jennifer; Compe, Emmanuel; Egly, Jean-Marc; DiGiovanna, John J; Kraemer, Kenneth H

2013-01-01

XPD (ERCC2) is a DNA helicase involved in nucleotide excision repair and in transcription as a structural bridge tying the transcription factor IIH (TFIIH) core with the cdk-activating kinase complex, which phosphorylates nuclear receptors. Mutations in XPD are associated with several different phenotypes, including trichothiodystrophy (TTD), with sulfur-deficient brittle hair, bone defects, and developmental abnormalities without skin cancer, xeroderma pigmentosum (XP), with pigmentary abnormalities and increased skin cancer, or XP/TTD with combined features, including skin cancer. We describe the varied clinical features and mutations in nine patients examined at the National Institutes of Health who were compound heterozygotes for XPD mutations but had different clinical phenotypes: four TTD, three XP, and two combined XP/TTD. We studied TFIIH-dependent transactivation by nuclear receptor for vitamin D (VDR) and thyroid in cells from these patients. The vitamin D stimulation ratio of CYP24 and osteopontin was associated with specific pairs of mutations (reduced in 5, elevated in 1) but not correlated with distinct clinical phenotypes. Thyroid receptor stimulation ratio for KLF9 was not significantly different from normal. XPD mutations frequently were associated with abnormal VDR stimulation in compound heterozygote patients with TTD, XP, or XP/TTD. PMID:23232694

Determinants of the electric field during transcranial direct current stimulation.

PubMed

Opitz, Alexander; Paulus, Walter; Will, Susanne; Antunes, Andre; Thielscher, Axel

2015-04-01

Transcranial direct current stimulation (tDCS) causes a complex spatial distribution of the electric current flow in the head which hampers the accurate localization of the stimulated brain areas. In this study we show how various anatomical features systematically shape the electric field distribution in the brain during tDCS. We constructed anatomically realistic finite element (FEM) models of two individual heads including conductivity anisotropy and different skull layers. We simulated a widely employed electrode montage to induce motor cortex plasticity and moved the stimulating electrode over the motor cortex in small steps to examine the resulting changes of the electric field distribution in the underlying cortex. We examined the effect of skull thickness and composition on the passing currents showing that thinner skull regions lead to higher electric field strengths. This effect is counteracted by a larger proportion of higher conducting spongy bone in thicker regions leading to a more homogenous current over the skull. Using a multiple regression model we could identify key factors that determine the field distribution to a significant extent, namely the thicknesses of the cerebrospinal fluid and the skull, the gyral depth and the distance to the anode and cathode. These factors account for up to 50% of the spatial variation of the electric field strength. Further, we demonstrate that individual anatomical factors can lead to stimulation "hotspots" which are partly resistant to electrode positioning. Our results give valuable novel insights in the biophysical foundation of tDCS and highlight the importance to account for individual anatomical factors when choosing an electrode montage. Copyright © 2015 Elsevier Inc. All rights reserved.

Cot/tpl2-MKK1/2-Erk1/2 controls mTORC1-mediated mRNA translation in Toll-like receptor–activated macrophages

PubMed Central

López-Pelaéz, Marta; Fumagalli, Stefano; Sanz, Carlos; Herrero, Clara; Guerra, Susana; Fernandez, Margarita; Alemany, Susana

2012-01-01

Cot/tpl2 is the only MAP3K that activates MKK1/2-Erk1/2 in Toll-like receptor–activated macrophages. Here we show that Cot/tpl2 regulates RSK, S6 ribosomal protein, and 4E-BP phosphorylation after stimulation of bone marrow–derived macrophages with lipopolysaccharide (LPS), poly I:C, or zymosan. The dissociation of the 4E-BP–eIF4E complex, a key event in the cap-dependent mRNA translation initiation, is dramatically reduced in LPS-stimulated Cot/tpl2-knockout (KO) macrophages versus LPS-stimulated wild-type (Wt) macrophages. Accordingly, after LPS activation, increased cap-dependent translation is observed in Wt macrophages but not in Cot/tpl2 KO macrophages. In agreement with these data, Cot/tpl2 increases the polysomal recruitment of the 5´ TOP eEF1α and eEF2 mRNAs, as well as of inflammatory mediator gene–encoding mRNAs, such as tumor necrosis factor α (TNFα), interleukin-6 (IL-6), and KC in LPS-stimulated macrophages. In addition, Cot/tpl2 deficiency also reduces total TNFα, IL-6, and KC mRNA expression in LPS-stimulated macrophages, which is concomitant with a decrease in their mRNA half-lives. Macrophages require rapid fine control of translation to provide an accurate and not self-damaging response to host infection, and our data show that Cot/tpl2 controls inflammatory mediator gene–encoding mRNA translation in Toll-like receptor–activated macrophages. PMID:22675026

Cot/tpl2-MKK1/2-Erk1/2 controls mTORC1-mediated mRNA translation in Toll-like receptor-activated macrophages.

PubMed

López-Pelaéz, Marta; Fumagalli, Stefano; Sanz, Carlos; Herrero, Clara; Guerra, Susana; Fernandez, Margarita; Alemany, Susana

2012-08-01

Cot/tpl2 is the only MAP3K that activates MKK1/2-Erk1/2 in Toll-like receptor-activated macrophages. Here we show that Cot/tpl2 regulates RSK, S6 ribosomal protein, and 4E-BP phosphorylation after stimulation of bone marrow-derived macrophages with lipopolysaccharide (LPS), poly I:C, or zymosan. The dissociation of the 4E-BP-eIF4E complex, a key event in the cap-dependent mRNA translation initiation, is dramatically reduced in LPS-stimulated Cot/tpl2-knockout (KO) macrophages versus LPS-stimulated wild-type (Wt) macrophages. Accordingly, after LPS activation, increased cap-dependent translation is observed in Wt macrophages but not in Cot/tpl2 KO macrophages. In agreement with these data, Cot/tpl2 increases the polysomal recruitment of the 5´ TOP eEF1α and eEF2 mRNAs, as well as of inflammatory mediator gene-encoding mRNAs, such as tumor necrosis factor α (TNFα), interleukin-6 (IL-6), and KC in LPS-stimulated macrophages. In addition, Cot/tpl2 deficiency also reduces total TNFα, IL-6, and KC mRNA expression in LPS-stimulated macrophages, which is concomitant with a decrease in their mRNA half-lives. Macrophages require rapid fine control of translation to provide an accurate and not self-damaging response to host infection, and our data show that Cot/tpl2 controls inflammatory mediator gene-encoding mRNA translation in Toll-like receptor-activated macrophages.

Management of an invasive and metastatic Sertoli cell tumor with associated myelotoxicosis in a dog

PubMed Central

Withers, Sita S.; Lawson, Corinne M.; Burton, Andrew G.; Rebhun, Robert B.; Steffey, Michele A.

2016-01-01

We describe the surgical and post-operative management of a large, invasive, and metastatic functional Sertoli cell tumor in a 9-year-old cryptorchid male Labrador retriever dog. Despite residual disease after surgery, bone marrow recovery occurred without administration of bone marrow stimulants and serum estradiol accurately predicted tumor recurrence. PMID:26933269

Bone as an effect compartment : models for uptake and release of drugs.

PubMed

Stepensky, David; Kleinberg, Lilach; Hoffman, Amnon

2003-01-01

"Bone-seeking agents" are drugs characterised by high affinity for bone, and are disposed in bone for prolonged periods of time while maintaining remarkably low systemic concentrations. As a consequence, the bone becomes a reservoir for bone-seeking agents, and a site of both desirable and adverse effects, depending on the pharmacological activities of the specific agent. For some agents, significant systemic effects may also be produced following their prolonged release from bone, a process that is governed mostly by the rate of bone remodelling. This review covers the pharmacokinetic and pharmacodynamic features of bone-seeking agents with different pharmacological properties, including drugs (bisphosphonates, drug-bisphosphonate conjugates, radiopharmaceuticals and fluoride), bone markers (tetracycline, bone imaging agents) and toxins (lead, chromium, aluminium). In addition, drugs that do not possess bone-seeking properties but are used for therapy of bone diseases (such as antibacterials for treatment of osteomyelitis) are discussed, along with targeting of these drugs to the bone by conjugation to bone-seeking agents, local delivery systems, and other approaches. The pharmacokinetic and pharmacodynamic behaviour of bone-seeking agents is extremely complex due to heterogeneity in bone morphology and physiology. This complexity, accompanied by difficulties in human bone research caused by ethical and other limitations, gave rise to modelling approaches to study bone drug disposition. This review describes the pharmacokinetic models that have been proposed to describe the pharmacokinetic behaviour of bone-seeking agents and predict bone concentrations of these agents for different doses and patient populations. Models of different types (compartmental and physiologically based) and of different complexity have been applied, but their relevance to drug effects in the bone tissue is limited since they describe the behaviour of the "average" drug molecule. Understanding of the cellular and molecular processes responsible for the heterogeneity of bone tissue will provide better comprehension of the influence of microenvironment on drug bone disposition and the resulting pharmacological response.

Functional recovery of neuronal activity in rat whisker-barrel cortex sensory pathway from freezing injury after transplantation of adult bone marrow stromal cells.

PubMed

Mori, Kentaro; Iwata, Junko; Miyazaki, Masahiro; Nakao, Yasuaki; Maeda, Minoru

2005-07-01

The effect of transplantation of adult bone marrow stromal cells (MSCs) into the freeze-lesioned left barrel field cortex in the rat was investigated by measurement of local cerebral glucose utilization (lCMR(glc)) in the anatomic structures of the whisker-to-barrel cortex sensory pathway. Bone marrow stromal cells or phosphate-buffered saline (PBS) were injected intracerebrally into the boundary zone 1 h after induction of the freezing cortical lesion. Three weeks after surgery, the 2-[(14)C]deoxyglucose method was used to measure lCMR(glc) during right whisker stimulation. The volume of the primary necrotic freezing lesion was significantly reduced (P<0.05), and secondary retrograde degeneration in the left ventral posteromedial (VPM) thalamic nucleus was diminished in the MSC-treated group. Local cerebral glucose utilization measurements showed that the freezing cortical lesion did not alter the metabolic responses to stimulation in the brain stem trigeminal nuclei, but eliminated the responses in the left VPM nucleus and periphery of the barrel cortex in the PBS-treated group. The left/right (stimulated/unstimulated) lCMR(glc) ratios were significantly improved in both the VPM nucleus and periphery of the barrel cortex in the MSC-treated group compared with the PBS-treated group (P<0.05). These results indicate that MSC transplantation in adults may stimulate metabolic and functional recovery in injured neuronal pathways.

Adenylate cyclase-stimulating, bone-resorbing and B TGF-like activities in canine apocrine cell adenocarcinoma of the anal sac.

PubMed

Weir, E C; Centrella, M; Matus, R E; Brooks, M L; Wu, T; Insogna, K L

1988-12-01

Canine apocrine cell adenocarcinoma of the anal sac (APO-AS) is a spontaneously occurring tumor that causes humorally mediated hypercalcemia in 90% of cases. To further define the nature of the responsible mediator in APO-AS, we examined tumor extracts from five APO-AS and four control tumors for adenylate cyclase-stimulating activity (ACSA). All extracts from APO-AS contained potent ACSA, whereas the four control tumors did not. The ACSA extracted from one tumor demonstrated a dose response curve parallel to that of synthetic bovinePTH-(1-34) and was 80% inhibited by Nle8,18,Tyr34 bPTH-(3-34)amide at a concentration of 10(-5) M. Extracts from three APO-AS and three control tumors were also examined for in vitro bone-resorbing activity (BRA). All APO-AS contained significant BRA, stimulating resorption 1.47 to 2.13-fold over basal, whereas none of the control tumors stimulated resorption. Purification of one extract using C18 reverse-phase high pressure liquid chromatography (RP-HPLC) resulted in a single sharp peak of ACSA which was 400-fold purified compared with the initial extract. This pool also contained significant bone-resorbing activity, whereas none of the adjacent pools did. Purification of a second extract using sequential CN and C18 RP-HPLC followed by size exclusion HPLC resulted in material that was at least 10,000-fold purified, and showed co-purification of ACSA and B TGF-like activity.

Magnetic targeting of mechanosensors in bone cells for tissue engineering applications.

PubMed

Hughes, Steven; Dobson, Jon; El Haj, Alicia J

2007-01-01

Mechanical signalling plays a pivotal role in maintaining bone cell function and remodelling of the skeleton. Our previous work has highlighted the potential role of mechano-induction in tissue engineering applications. In particular, we have highlighted the potential for using magnetic particle techniques for tissue engineering applications. Previous studies have shown that manipulation of integrin attached magnetic particles leads to changes in intracellular calcium signalling within osteoblasts. However, due to the phenomenon of particle internalisation, previous studies have typically focused on short-term stimulation experiments performed within 1-2 h of particle attachment. For tissue engineering applications, bone tissue growth occurs over a period of 3-5 weeks. To date, no study has investigated the cellular responses elicited from osteoblasts over time following stimulation with internalised magnetic particles. Here, we demonstrate the long-term biocompatibility of 4.5 microm RGD-coated particles with osteoblasts up to 21 days in culture, and detail a time course of responses elicited from osteoblasts following mechanical stimulation with integrin attached magnetic particles (<2h post attachment) and internalised particles (>48h post attachment). Mechanical manipulation of both integrin attached and internalised particles were found to induce intracellular calcium signalling. It is concluded that magnetic particles offer a tool for applying controlled mechanical forces to osteoblasts, and can be used to stimulate intracellular calcium signalling over prolonged periods of time. Magnetic particle technology presents a potentially valuable tool for tissue engineering which permits the delivery of highly localised mechano-inductive forces directly to cells.

Angiogenic CXC chemokine expression during differentiation of human mesenchymal stem cells towards the osteoblastic lineage.

PubMed

Bischoff, D S; Zhu, J H; Makhijani, N S; Kumar, A; Yamaguchi, D T

2008-02-15

The potential role of ELR(+) CXC chemokines in early events in bone repair was studied using human mesenchymal stem cells (hMSCs). Inflammation, which occurs in the initial phase of tissue healing in general, is critical to bone repair. Release of cytokines from infiltrating immune cells and injured bone can lead to recruitment of MSCs to the region of repair. CXC chemokines bearing the Glu-Leu-Arg (ELR) motif are also released by inflammatory cells and serve as angiogenic factors stimulating chemotaxis and proliferation of endothelial cells. hMSCs, induced to differentiate with osteogenic medium (OGM) containing ascorbate, beta-glycerophosphate (beta-GP), and dexamethasone (DEX), showed an increase in mRNA and protein secretion of the ELR(+) CXC chemokines CXCL8 and CXCL1. CXCL8 mRNA half-life studies reveal an increase in mRNA stability upon OGM stimulation. Increased expression and secretion is a result of DEX in OGM and is dose-dependent. Inhibition of the glucocorticoid receptor with mifepristone only partially inhibits DEX-stimulated CXCL8 expression indicating both glucocorticoid receptor dependent and independent pathways. Treatment with signal transduction inhibitors demonstrate that this expression is due to activation of the ERK and p38 mitogen-activated protein kinase (MAPK) pathways and is mediated through the G(alphai)-coupled receptors. Angiogenesis assays demonstrate that OGM-stimulated conditioned media containing secreted CXCL8 and CXCL1 can induce angiogenesis of human microvascular endothelial cells in an in vitro Matrigel assay. Copyright 2007 Wiley-Liss, Inc.

Fluid shear stress stimulates prostaglandin and nitric oxide release in bone marrow-derived preosteoclast-like cells

NASA Technical Reports Server (NTRS)

McAllister, T. N.; Du, T.; Frangos, J. A.

2000-01-01

Bone is a porous tissue that is continuously perfused by interstitial fluid. Fluid flow, driven by both vascular pressure and mechanical loading, may generate significant shear stresses through the canaliculi as well as along the bone lining at the endosteal surface. Both osteoblasts and osteocytes produce signaling factors such as prostaglandins and nitric in response to fluid shear stress (FSS); however, these humoral agents appear to have more profound affects on osteoclast activity at the endosteal surface. We hypothesized that osteoclasts and preosteoclasts may also be mechanosensitive and that osteoclast-mediated autocrine signaling may be important in bone remodeling. In this study, we investigated the effect of FSS on nitric oxide (NO), prostaglandin E(2) (PGE(2)), and prostacyclin (PGI(2)) release by neonatal rat bone marrow-derived preosteoclast-like cells. These cells were tartrate-resistant acid phosphatase (TRAP) positive, weakly nonspecific esterase (NSE) positive, and capable of fusing into calcitonin-responsive, bone-resorbing, multinucleated cells. Bone marrow-derived preosteoclast-like cells exposed for 6 h to a well-defined FSS of 16 dynes/cm(2) produced NO at a rate of 7.5 nmol/mg protein/h, which was 10-fold that of static controls. This response was completely abolished by 100 microM N(G)-amino-L-arginine (L-NAA). Flow also stimulated PGE(2) production (3.9 microg/mg protein/h) and PGI(2) production (220 pg/mg protein/h). L-NAA attenuated flow-induced PGE(2) production by 30%, suggesting that NO may partially modulate PGE(2) production. This is the first report demonstrating that marrow derived cells are sensitive to FSS and that autocrine signaling in these cells may play an important role in load-induced remodeling and signal transduction in bone. Copyright 2000 Academic Press.

The Estrogen Receptor-α in Osteoclasts Mediates the Protective Effects of Estrogens on Cancellous But Not Cortical Bone

PubMed Central

Martin-Millan, Marta; Almeida, Maria; Ambrogini, Elena; Han, Li; Zhao, Haibo; Weinstein, Robert S.; Jilka, Robert L.; O'Brien, Charles A.; Manolagas, Stavros C.

2010-01-01

Estrogens attenuate osteoclastogenesis and stimulate osteoclast apoptosis, but the molecular mechanism and contribution of these effects to the overall antiosteoporotic efficacy of estrogens remain controversial. We selectively deleted the estrogen receptor (ER)α from the monocyte/macrophage cell lineage in mice (ERαLysM−/−) and found a 2-fold increase in osteoclast progenitors in the marrow and the number of osteoclasts in cancellous bone, along with a decrease in cancellous bone mass. After loss of estrogens these mice failed to exhibit the expected increase in osteoclast progenitors, the number of osteoclasts in bone, and further loss of cancellous bone. However, they lost cortical bone indistinguishably from their littermate controls. Mature osteoclasts from ERαLysM−/− were resistant to the proapoptotic effect of 17β-estradiol. Nonetheless, the effects of estrogens on osteoclasts were unhindered in mice bearing an ERα knock-in mutation that prevented binding to DNA. Moreover, a polymeric form of estrogen that is not capable of stimulating the nuclear-initiated actions of ERα was as effective as 17β-estradiol in inducing osteoclast apoptosis in cells with the wild-type ERα. We conclude that estrogens attenuate osteoclast generation and life span via cell autonomous effects mediated by DNA-binding-independent actions of ERα. Elimination of these effects is sufficient for loss of bone in the cancellous compartment in which complete perforation of trabeculae by osteoclastic resorption precludes subsequent refilling of the cavities by the bone-forming osteoblasts. However, additional effects of estrogens on osteoblasts, osteocytes, and perhaps other cell types are required for their protective effects on the cortical compartment, which constitutes 80% of the skeleton. PMID:20053716

Acoustic stimulation on the round window for active middle ear implants.

PubMed

Seong, Kiwoong; Lee, Kyuyup; Puria, Sunil; Cho, Jin-Ho

2018-06-01

Many clinical reports have discussed the effectiveness of stimulating the ear's round window (RW) with a tool to mitigate conductive and mixed hearing loss. The RW is one of the two openings from the middle ear into the inner ear. Various methods have been proposed to construct a highly efficient, easily implanted, and reliable RW transducer. Devices, however, such as floating mass transducers, have difficulty establishing proper contact without some degree of bone incision around the RW. Additionally, vibration energy may not be fully transmitted to the cochlea, but instead will be spread through the soft tissue around the transducer. We propose a more direct RW stimulation with very high acoustical impedance using a receiver that is a volume velocity source. We expect this source to overcome large acoustic impedance by maximizing sound pressure in a confined space, the RW niche. To verify the effectiveness of the proposed method, ear canal pressure, RW pressure, and stapes velocity are measured by acoustic RW stimulation of human temporal bones. Copyright © 2018 Elsevier Ltd. All rights reserved.

Modifying the Genetic Regulation of Bone and Cartilage Cells and Associated Tissue by EMF Stimulation Fields and Uses Thereof

NASA Technical Reports Server (NTRS)

Goodwin, Thomas J. (Inventor); Shackelford, Linda C. (Inventor)

2014-01-01

An apparatus and method to modify the genetic regulation of mammalian tissue, bone, or any combination. The method may be comprised of the steps of tuning at least one predetermined profile associated with at least one time-varying stimulation field thereby resulting in at least one tuned time-varying stimulation field comprised of at least one tuned predetermined profile, wherein said at least one tuned predetermined profile is comprised of a plurality of tuned predetermined figures of merit and is controllable through at least one of said plurality of tuned predetermined figures of merit, wherein said plurality of predetermined tuned figures of merit is comprised of a tuned B-Field magnitude, tuned rising slew rate, tuned rise time, tuned falling slew rate, tuned fall time, tuned frequency, tuned wavelength, and tuned duty cycle; and exposing mammalian chondrocytes, osteoblasts, osteocytes, osteoclasts, nucleus pulposus, associated tissue, or any combination to said at least one tuned time-varying stimulation field comprised of said at least one tuned predetermined profile for a predetermined tuned exposure time or plurality of tuned exposure time sequences.

Autocrine stimulation of osteoblast activity by Wnt5a in response to TNF-α in human mesenchymal stem cells

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

Thiazide diuretics directly induce osteoblast differentiation and mineralized nodule formation by targeting a NaCl cotransporter in bone

PubMed Central

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

A distinct regulatory region of the Bmp5 locus activates gene expression following adult bone fracture or soft tissue injury.

PubMed

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.

Recombinant human bone morphogenetic protein-2 stimulates bone formation during interfrontal suture expansion in rabbits.

PubMed

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.

Bone up: craniomandibular development and hard-tissue biomineralization in neonate mice.

PubMed

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.

Estrogen-induced myelotoxicity in dogs: A review

PubMed Central

Sontas, Hasan B.; Dokuzeylu, Banu; Turna, Ozge; Ekici, Hayri

2009-01-01

Exogenous estrogens used for therapeutic purposes or endogenous estrogen sources such as functional Sertoli cell or ovarian granulosa cell tumors may cause bone marrow toxicity in dogs. The condition is characterized by hematologic abnormalities including thrombocytopenia, anemia, and leukocytosis or leukopenia. Despite intensive therapy with blood or platelet-rich transfusions, broad-spectrum antibiotics, steroids, and bone marrow stimulants, prognosis is unfavorable. Due to the the risk of stimulating the development of uterine diseases and the potential for inducing aplastic anemia, estrogen use in dogs is best avoided where possible. This paper describes the causes of estrogen-induced myelotoxicity, the clinical presentation of the patients, the diagnosis, and the treatment options in the dog. PMID:20046604

Parathyroid hormone regulation of the human bone sialoprotein gene transcription is mediated through two cAMP response elements.

PubMed

Araki, Shouta; Mezawa, Masaru; Sasaki, Yoko; Yang, Li; Li, Zhengyang; Takai, Hideki; Nakayama, Youhei; Ogata, Yorimasa

2009-03-01

Parathyroid hormone (PTH) regulates serum calcium and inorganic phosphate levels through its actions on kidney and bone. Bone sialoprotein (BSP) is an early marker of osteoblast differentiation and bone metabolism. We here report that two cAMP response elements (CRE) in the human BSP gene promoter are target of PTH. In human osteoblast-like Saos2 cells, PTH (human 1-34 PTH, 10 nM) increased BSP mRNA and protein levels at 3 h. From transient transfection assays, 2- to 2.5-fold increase in transcription by PTH was observed at 3 and 6 h in -184, -211, -428, -868, and -927 luciferase constructs that included the human BSP gene promoter. Effect of PTH was abrogated by 2 bp mutations in either the CRE1 (-79 to -72) or CRE2 (-674 to -667). Luciferase activities induced by PTH were blocked by protein kinase A inhibitor H89 and tyrosine kinase inhibitor herbimycin A. Gel shift analyses showed that PTH increased binding of nuclear proteins to the CRE1 and CRE2 elements. The CRE1-protein and CRE2-protein complexes were disrupted by CRE binding protein 1 (CREB1) antibodies and supershifted by phospho-CREB1 antibody. ChIP assays detected binding of CREB1 and phospho-CREB1 to a chromatin fragment containing CRE1 and CRE2, and increased binding of phospho-CREB1 to the both sites. These studies demonstrate that PTH stimulates human BSP gene transcription by targeting the two CREs in the promoter of the human BSP gene.

Peripheral mineralization of a 3D biodegradable tubular construct as a way to enhance guidance stabilization in spinal cord injury regeneration.

PubMed

Oliveira, A L; Sousa, E C; Silva, N A; Sousa, N; Salgado, A J; Reis, R L

2012-11-01

Spinal cord injuries (SCI) present a major challenge to therapeutic development due to its complexity. Combinatorial approaches using biodegradable polymers that can simultaneously provide a tissue scaffold, a cell vehicle, and a reservoir for sustained drug delivery have shown very promising results. In our previous studies we have developed a novel hybrid system consisting of starch/poly-e-caprolactone (SPCL) semi-rigid tubular porous structure, based on a rapid prototyping technology, filled by a gellan gum hydrogel concentric core for the regeneration within spinal-cord injury sites. In the present work we intend to promote enhanced osteointegration on these systems by pre-mineralizing specifically the external surfaces of the SPCL tubular structures, though a biomimetic strategy, using a sodium silicate gel as nucleating agent. The idea is to create two different cell environments to promote axonal regeneration in the interior of the constructs while inducing osteogenic activity on its external surface. By using a Teflon cylinder to isolate the interior of the scaffold, it was possible to observe the formation of a bone-like poorly crystalline carbonated apatite layer continuously formed only in the external side of the tubular structure. This biomimetic layer was able to support the adhesion of Bone Marrow Mesenchymal Stem Cells, which have gone under cytoskeleton reorganization in the first hours of culture when compared to cells cultured on uncoated scaffolds. This strategy can be a useful route for locally stimulate bone tissue regeneration and facilitating early bone ingrowth.

Effectiveness of decoronation technique in the treatment of ankylosis: A systematic review.

PubMed

Mohadeb, Jhassu Varsha Naveena; Somar, Mirinal; He, Hong

2016-08-01

Dentoalveolar ankylosis in growing patients is complex leading to continuing root replacement resorption, tooth infra-position, or may even affect the development of alveolar ridge and adjacent teeth. While extraction of ankylosed teeth might be associated with bone loss, decoronation of the offending tooth (removal of crown portion and instrumentation of pulp canal to stimulate bleeding) has been suggested as a more conservative approach of bone preservation until definitive implant placement is planned. To primarily assess the efficacy of bone width and height preservation around ankylosed permanent teeth following decoronation. Pubmed, Embase, Ovid Medline, Thomson's ISI Web of Science and Cochrane library were searched from the year 1984 up to May 2015. Two authors conducted the data extraction. To eliminate publication bias, Open Grey literature and Pro-quest Dissertation Abstracts and Thesis database was also consulted. Through our strict selection criteria, only 12 articles were considered for eligibility. No randomized controlled trials were identified. Only one retrospective cohort study, four case series and seven case reports, were analyzed. Following decoronation, preservation of ridge height and ridge width were both noted. To maximize the benefits of decoronation, a timely and wellmonitored intervention is required. Treatment in patients, who have surpassed pubertal growth peaks, may not yield maximum effective treatment outcomes. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Low-intensity pulsed ultrasound stimulation facilitates in vitro osteogenic differentiation of human adipose-derived stem cells via up-regulation of heat shock protein (HSP)70, HSP90, and bone morphogenetic protein (BMP) signaling pathway.

PubMed

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).

Effects of quercetin and quercetin 3-glucuronide on the expression of bone sialoprotein gene.

PubMed

Kim, Dong-Soon; Takai, Hideki; Arai, Masato; Araki, Shouta; Mezawa, Masaru; Kawai, Yoshichika; Murota, Kaeko; Terao, Junji; Ogata, Yorimasa

2007-06-01

Quercetin is a typical flavonol-type flavonoid and is present in a variety of vegetables, and their antioxidant effect implies their possible role in the prevention of oxidative stress related chronic diseases. Bone sialoprotein (BSP) is a noncollagenous protein of the extracellular matrix in the mineralized connective tissues that has been implicated in the nucleation of hydroxyapatite crystals. Previously, we reported that isoflavone (genistein) activated BSP gene transcription is mediated through an inverted CCAAT box in the proximal BSP gene promoter. The present study investigates the regulation of BSP transcription in a rat osteoblast-like cell line, ROS 17/2.8 cells, by quercetin and its conjugated metabolite quercetin 3-glucuronide. Quercetin and quercetin 3-glucuronide (5 microM) increased the BSP mRNA levels at 12 h and quercetin upregulated the Cbfa1/Runx2 mRNA expression at 12 h. From transient transfection assays using various sized BSP promoter-luciferase constructs, quercetin increased the luciferase activity of the construct (pLUC3), including the promoter sequence nucleotides -116 to -43. Transcriptional stimulations by quercetin were almost completely abrogated in the constructs that included 2 bp mutations in the inverted CCAAT and FRE elements whereas the CCAAT-protein complex did not change after stimulation by quercetin according to gel shift assays. Quercetin increased the nuclear protein binding to the FRE and 3'-FRE. These data suggest that quercetin and quercetin 3-glucuronide increased the BSP mRNA expression, and that the inverted CCAAT and FRE elements in the promoter of the BSP gene are required for quercetin induced BSP transcription.

Platelet “First Responders” in Wound Response, Cancer, and Metastasis

PubMed Central

Menter, David G.; Kopetz, Scott; Hawk, Ernest; Sood, Anil K.; Loree, Jonathan M; Gresele, Paolo; Honn, Kenneth V.

2017-01-01

Platelets serve as “First Responders” during normal wounding and homeostasis. Arising from bone marrow stem cell lineage megakaryocytes, anucleate platelets can influence inflammation and immune regulation. Biophysically, platelets are optimized due to size and discoid morphology to distribute near vessel walls, monitor vascular integrity and initiate quick responses to vascular lesions. Adhesion receptors linked to a highly reactive filopodia-generating cytoskeleton maximizes their vascular surface contact allowing rapid response capabilities. Functionally, platelets normally initiate rapid clotting, vasoconstriction, inflammation and wound biology that leads to sterilization, tissue repair and resolution. Platelets also are among the first to sense, phagocytize, decorate, or react to pathogens in the circulation. These platelet first responder properties are commandeered during chronic inflammation, cancer progression and metastasis. Leaky or inflammatory reaction blood vessel genesis during carcinogenesis provides opportunities for platelet invasion into tumors. Cancer is thought of as a non-healing or chronic wound that can be actively aided by platelet mitogenic properties to stimulate tumor growth. This growth ultimately outstrips circulatory support leads to angiogenesis and intravasation of tumor cells into the blood stream. Circulating tumor cells reengage additional platelets, which facilitates tumor cell adhesion, arrest and extravasation and metastasis. This process, along with the hypercoagulable states associated with malignancy is amplified by IL6 production in tumors that stimulate liver thrombopoietin production and elevates circulating platelet numbers by thrombopoiesis in the bone marrow. These complex interactions and the “First Responder” role of platelets during diverse physiologic stresses provides a useful therapeutic target that deserves further exploration. PMID:28730545

Control of cell behaviour through nanovibrational stimulation: nanokicking

NASA Astrophysics Data System (ADS)

Robertson, Shaun N.; Campsie, Paul; Childs, Peter G.; Madsen, Fiona; Donnelly, Hannah; Henriquez, Fiona L.; Mackay, William G.; Salmerón-Sánchez, Manuel; Tsimbouri, Monica P.; Williams, Craig; Dalby, Matthew J.; Reid, Stuart

2018-05-01

Mechanical signals are ubiquitous in our everyday life and the process of converting these mechanical signals into a biological signalling response is known as mechanotransduction. Our understanding of mechanotransduction, and its contribution to vital cellular responses, is a rapidly expanding field of research involving complex processes that are still not clearly understood. The use of mechanical vibration as a stimulus of mechanotransduction, including variation of frequency and amplitude, allows an alternative method to control specific cell behaviour without chemical stimulation (e.g. growth factors). Chemical-independent control of cell behaviour could be highly advantageous for fields including drug discovery and clinical tissue engineering. In this review, a novel technique is described based on nanoscale sinusoidal vibration. Using finite-element analysis in conjunction with laser interferometry, techniques that are used within the field of gravitational wave detection, optimization of apparatus design and calibration of vibration application have been performed. We further discuss the application of nanovibrational stimulation, or `nanokicking', to eukaryotic and prokaryotic cells including the differentiation of mesenchymal stem cells towards an osteoblast cell lineage. Mechanotransductive mechanisms are discussed including mediation through the Rho-A kinase signalling pathway. Optimization of this technique was first performed in two-dimensional culture using a simple vibration platform with an optimal frequency and amplitude of 1 kHz and 22 nm. A novel bioreactor was developed to scale up cell production, with recent research demonstrating that mesenchymal stem cell differentiation can be efficiently triggered in soft gel constructs. This important step provides first evidence that clinically relevant (three-dimensional) volumes of osteoblasts can be produced for the purpose of bone grafting, without complex scaffolds and/or chemical induction. Initial findings have shown that nanovibrational stimulation can also reduce biofilm formation in a number of clinically relevant bacteria. This demonstrates additional utility of the bioreactor to investigate mechanotransduction in other fields of research. This article is part of a discussion meeting issue `The promises of gravitational-wave astronomy'.

Control of cell behaviour through nanovibrational stimulation: nanokicking.

PubMed

Robertson, Shaun N; Campsie, Paul; Childs, Peter G; Madsen, Fiona; Donnelly, Hannah; Henriquez, Fiona L; Mackay, William G; Salmerón-Sánchez, Manuel; Tsimbouri, Monica P; Williams, Craig; Dalby, Matthew J; Reid, Stuart

2018-05-28

Mechanical signals are ubiquitous in our everyday life and the process of converting these mechanical signals into a biological signalling response is known as mechanotransduction. Our understanding of mechanotransduction, and its contribution to vital cellular responses, is a rapidly expanding field of research involving complex processes that are still not clearly understood. The use of mechanical vibration as a stimulus of mechanotransduction, including variation of frequency and amplitude, allows an alternative method to control specific cell behaviour without chemical stimulation (e.g. growth factors). Chemical-independent control of cell behaviour could be highly advantageous for fields including drug discovery and clinical tissue engineering. In this review, a novel technique is described based on nanoscale sinusoidal vibration. Using finite-element analysis in conjunction with laser interferometry, techniques that are used within the field of gravitational wave detection, optimization of apparatus design and calibration of vibration application have been performed. We further discuss the application of nanovibrational stimulation, or 'nanokicking', to eukaryotic and prokaryotic cells including the differentiation of mesenchymal stem cells towards an osteoblast cell lineage. Mechanotransductive mechanisms are discussed including mediation through the Rho-A kinase signalling pathway. Optimization of this technique was first performed in two-dimensional culture using a simple vibration platform with an optimal frequency and amplitude of 1 kHz and 22 nm. A novel bioreactor was developed to scale up cell production, with recent research demonstrating that mesenchymal stem cell differentiation can be efficiently triggered in soft gel constructs. This important step provides first evidence that clinically relevant (three-dimensional) volumes of osteoblasts can be produced for the purpose of bone grafting, without complex scaffolds and/or chemical induction. Initial findings have shown that nanovibrational stimulation can also reduce biofilm formation in a number of clinically relevant bacteria. This demonstrates additional utility of the bioreactor to investigate mechanotransduction in other fields of research.This article is part of a discussion meeting issue 'The promises of gravitational-wave astronomy'. © 2018 The Author(s).

Intracochlear pressure measurements to study bone conduction transmission: State-of-the art and proof of concept of the experimental Procedure

NASA Astrophysics Data System (ADS)

Borgers, Charlotte; van Wieringen, Astrid; D'hondt, Christiane; Verhaert, Nicolas

2018-05-01

The cochlea is the main contributor in bone conduction perception. Measurements of differential pressure in the cochlea give a good estimation of the cochlear input provided by bone conduction stimulation. Recent studies have proven the feasibility of intracochlear pressure measurements in chinchillas and in human temporal bones to study bone conduction. However, similar measurements in fresh-frozen whole human cadaveric heads could give a more realistic representation of the five different transmission pathways of bone conduction to the cochlea compared to human temporal bones. The aim of our study is to develop and validate a framework for intracochlear pressure measurements to evaluate different aspects of bone conduction in whole human cadaveric heads. A proof of concept describing our experimental setup is provided together with the procedure. Additionally, we also present a method to fix the stapes footplate in order to simulate otosclerosis in human temporal bones. The effectiveness of this method is verified by some preliminary results.

Systematic evaluation of a tissue-engineered bone for maxillary sinus augmentation in large animal canine model.

PubMed

Wang, Shaoyi; Zhang, Zhiyuan; Xia, Lunguo; Zhao, Jun; Sun, Xiaojuan; Zhang, Xiuli; Ye, Dongxia; Uludağ, Hasan; Jiang, Xinquan

2010-01-01

The objective of this study is to systematically evaluate the effects of a tissue-engineered bone complex for maxillary sinus augmentation in a canine model. Twelve sinus floor augmentation surgeries in 6 animals were performed bilaterally and randomly repaired with the following 3 groups of grafts: group A consisted of tissue-engineered osteoblasts/beta-TCP complex (n=4); group B consisted of beta-TCP alone (n=4); group C consisted of autogenous bone obtained from iliac crest as a positive control (n=4). All dogs had uneventful healings following the surgery. Sequential polychrome fluorescent labeling, maxillofacial CT, microhardness tests, as well as histological and histomorphometric analyses indicated that the tissue-engineered osteoblasts/beta-TCP complex dramatically promoted bone formation and mineralization and maximally maintained the height and volume of elevated maxillary sinus. By comparison, both control groups of beta-TCP or autologous iliac bone showed considerable resorption and replacement by fibrous or fatty tissue. We thus conclude that beta-TCP alone could barely maintain the height and volume of the elevated sinus floor, and that the transplantation of autogenous osteoblasts on beta-TCP could promote earlier bone formation and mineralization, maximally maintain height, volume and increase the compressive strength of augmented maxillary sinus. This tissue engineered bone complex might be a better alternative to autologous bone for the clinical edentulous maxillary sinus augmentation. Copyright (c) 2009 Elsevier Inc. All rights reserved.

Alkaline biodegradable implants for osteoporotic bone defects--importance of microenvironment pH.

PubMed

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.

Human parathyroid hormone-(1-38) restores cancellous bone to the immobilized, osteopenic proximal tibial metaphysis in rats

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.

An Endochondral Ossification-Based Approach to Bone Repair: Chondrogenically Primed Mesenchymal Stem Cell-Laden Scaffolds Support Greater Repair of Critical-Sized Cranial Defects Than Osteogenically Stimulated Constructs In Vivo.

PubMed

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.

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.

The cytokine release inhibitory drug CRID3 targets ASC oligomerisation in the NLRP3 and AIM2 inflammasomes.

PubMed

Coll, Rebecca C; Robertson, Avril; Butler, Mark; Cooper, Matthew; O'Neill, Luke A J

2011-01-01

The Inflammasomes are multi-protein complexes that regulate caspase-1 activation and the production of the pro-inflammatory cytokine IL-1β. Previous studies identified a class of diarylsulfonylurea containing compounds called Cytokine Release Inhibitory Drugs (CRIDs) that inhibited the post-translational processing of IL-1β. Further work identified Glutathione S-Transferase Omega 1 (GSTO1) as a possible target of these CRIDs. This study aimed to investigate the mechanism of the inhibitory activity of the CRID CP-456,773 (termed CRID3) in light of recent advances in the area of inflammasome activation, and to clarify the potential role of GSTO1 in the regulation of IL-1β production. In murine bone marrow derived macrophages, CRID3 inhibited IL-1β secretion and caspase 1 processing in response to stimulation of NLRP3 and AIM2 but not NLRC4. CRID3 also prevented AIM2 dependent pyroptosis in contrast to the NLRP3 inhibitors glyburide and parthenolide, which do not inhibit AIM2 activation. Confocal microscopy and Western blotting assays indicated that CRID3 inhibited the formation of ASC complexes or 'specks' in response to NLRP3 and AIM2 stimulation. Co-immunoprecipitation assays show that GSTO1 interacted with ASC. These results identify CRID3 as a novel inhibitor of the NLRP3 and AIM2 inflammasomes and provide an insight into the mechanism of action of this small molecule. In addition GSTO1 may be a component of the inflammasome that is required for ASC complex formation. © 2011 Coll, O’Neill.

Programmable Mechanobioreactor for Exploration of the Effects of Periodic Vibratory Stimulus on Mesenchymal Stem Cell Differentiation

PubMed Central

Cashion, Avery T.; Caballero, Montserrat; Halevi, Alexandra; Pappa, Andrew; Dennis, Robert G.

2014-01-01

Abstract A programmable bioreactor using a voice-coil actuator was developed to enable research on the effects of periodic vibratory stimulus on human and porcine mesenchymal stem cells (MSCs). We hypothesized that low frequency vibrations would result in a cartilage phenotype and higher frequency vibrations would result in a bone phenotype. The mechanical stimulation protocol is adjusted from a computer external to the incubator via a USB cable. Once programmed, the embedded microprocessor and sensor system on the bioreactor execute the protocol independent of the computer. In each test, a sinusoidal stimulus was applied to a culture plate in 1-min intervals with a 15-min rest following each, for a total of 15 h per day for 10 days. Frequencies of 1 and 100 Hz were applied to cultures of both human and porcine umbilical cord–derived MSCs. Chondrogenesis was determined by Alcian blue staining for glycosaminoglycans and an increased differentiation index (ratio of mRNA for collagen II and collagen I). Osteogenic differentiation was indicated with Alizarin red for calcium staining and increased bone morphogenetic protein 2 mRNA. One-hertz stimulation resulted in a cartilage phenotype for both human and porcine MSCs, while 100-Hz stimulation resulted in a bone phenotype. PMID:24570842

Augmented macrophage differentiation and polarization of tumor-associated macrophages towards M1 subtype in listeria-administered tumor-bearing host.

PubMed

Rai, Rakesh K; Vishvakarma, Naveen K; Mohapatra, Tribhuban M; Singh, Sukh Mahendra

2012-09-01

This study investigates the effect of Listeria administration on differentiation of macrophages from precursor bone marrow cells and functional status of tumor-associated macrophages (TAM). Listeria administration not only resulted in an augmented infiltration of tumor by F4/80 macrophages but also repolarized the functional status of TAM displaying features of some M1 macrophage subtype with upregulated phagocytosis and tumoricidal activity accompanied by altered expression of monocarboxylate transporter-1, toll-like receptor-2, surface markers: CD11c, interleukin-2 receptor, CD62L, and secreted molecules: nitric oxide, interleukin (IL)-1, IL-6, tumor necrosis factor-α, and vascular endothelial growth factor. Declined tumor cell survival and modulated repertoire of cytokines: interferon-γ, IL-6, IL-10, and transforming growth factor-β in tumor microenvironment indicated their role in polarization of TAM towards proinflammatory state. Bone marrow cell of Listeria-administered tumor-bearing mice showed augmented survival, declined expression of p53 upregulated modulator of apoptosis with an upregulated differentiation into activation responsive bone marrow-derived macrophages along with altered expression of macrophage-colony stimulating factor, macrophage-colony stimulating factor receptor, and granulocyte macrophage-colony stimulating factor receptor. These findings indicate that Listeria infection is associated with an augmented differentiation of macrophages accompanied by tumoricidal activation of TAM.

Delivery of small molecules for bone regenerative engineering: preclinical studies and potential clinical applications

PubMed Central

Laurencin, Cato T.; Ashe, Keshia M.; Henry, Nicole; Kan, Ho Man; Lo, Kevin W-H.

2014-01-01

Stimulation of bone regeneration using growth factors is a promising approach for musculoskeletal regenerative engineering. Common limitations with protein growth factors are high manufacturing costs, protein instability, contamination issues, and unwanted immunogenic responses of the host. New strategies for bone regeneration that obviate these problems can have a significant impact on the treatment of skeletal injury and diseases. Over the past decade, a large number of small molecules with the potential of regenerating skeletal tissue have been reported in the literature. Here, we review this literature, paying specific attention to the prospects for small molecule-based bone-regenerative engineering. We also review the preclinical study of small molecules associated with bone regeneration. PMID:24508820

Callus remodelling model

NASA Astrophysics Data System (ADS)

Miodowska, Justyna; Bielski, Jan; Kromka-Szydek, Magdalena

2018-01-01

The objective of this paper is to investigate the healing process of the callus using bone remodelling approach. A new mathematical model of bone remodelling is proposed including both underload and overload resorption, as well as equilibrium and bone growth states. The created model is used to predict the stress-stimulated change in the callus density. The permanent and intermittent loading programs are considered. The analyses indicate that obtaining a sufficiently high values of the callus density (and hence the elasticity) modulus is only possible using time-varying load parameters. The model predictions also show that intermittent loading program causes delayed callus healing. Understanding how mechanical conditions influence callus remodelling process may be relevant in the bone fracture treatment and initial bone loading during rehabilitation.

Biodegradable Magnesium Alloys Developed as Bone Repair Materials: A Review

PubMed Central

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

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.

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.

A histologic, histomorphometric, and radiographic comparison between two complexes of CenoBoen/CenoMembrane and Bio-Oss/Bio-Gide in lateral ridge augmentation: A clinical trial.

PubMed

Amoian, Babak; Moudi, Ehsan; Majidi, Maryam Seyed; Ali Tabatabaei, S M

2016-09-01

Several grafting materials have been used for alveolar ridge augmentation. The literature lacks researches to compare CenoBone to other grafting materials. The aim of this study was to compare CenoBone/CenoMembrane complex to Bio-Oss/Bio-Gide complex in lateral alveolar bone augmentation in terms of radiographic, histologic, and histomorphometric parameters. In this randomized controlled trial, ten patients who needed lateral ridge augmentation were selected and augmentations were done using either of CenoBone/CenoMembrane or Bio-Oss/Bio-Gide complexes. In the re-entry surgery in 6 months following augmentation, core biopsies were taken and clinical, radiographic, histologic, and histomorphometric evaluations were performed. No statistically significant difference was seen between groups except for the number of blood vessels and percentage of residual graft materials. CenoBone seems to present a comparable lateral ridge augmentation to Bio-Oss in.

Interplay between self-assembled structure of bone morphogenetic protein-2 (BMP-2) and osteoblast functions in three-dimensional titanium alloy scaffolds: Stimulation of osteogenic activity.

PubMed

Nune, K C; Kumar, A; Murr, L E; Misra, R D K

2016-02-01

Three-dimensional cellular scaffolds are receiving significant attention in bone tissue engineering to treat segmental bone defects. However, there are indications of lack of significant osteoinductive ability of three-dimensional cellular scaffolds. In this regard, the objective of the study is to elucidate the interplay between bone morphogenetic protein (BMP-2) and osteoblast functions on 3D mesh structures with different porosities and pore size that were fabricated by electron beam melting. Self-assembled dendritic microstructure with interconnected cellular-type morphology of BMP-2 on 3D scaffolds stimulated osteoblast functions including adhesion, proliferation, and mineralization, with prominent effect on 2-mm mesh. Furthermore, immunofluorescence studies demonstrated higher density and viability of osteoblasts on lower porosity mesh structure (2 mm) as compared to 3- and 4-mm mesh structures. Enhanced filopodia cellular extensions with extensive cell spreading was observed on BMP-2 treated mesh structures, a behavior that is attributed to the unique self-assembled structure of BMP-2 that effectively communicates with the cells. The study underscores the potential of BMP-2 in imparting osteoinductive capability to the 3D printed scaffolds. © 2015 Wiley Periodicals, Inc.

Black rice (Oryza sativa L.) extracts induce osteoblast differentiation and protect against bone loss in ovariectomized rats.

PubMed

Jang, Woo-Seok; Seo, Cho-Rong; Jang, Hwan Hee; Song, No-Joon; Kim, Jong-Keun; Ahn, Jee-Yin; Han, Jaejoon; Seo, Woo Duck; Lee, Young Min; Park, Kye Won

2015-01-01

Osteoporosis, an age associated skeletal disease, exhibits increased adipogenesis at the expense of osteogenesis from common osteoporotic bone marrow cells. In this study, black rice (Oryza sativa L.) extracts (BRE) were identified as osteogenic inducers. BRE stimulated the alkaline phosphatase (ALP) activity in both C3H10T1/2 and primary bone marrow cells. Similarly, BRE increased mRNA expression of ALP and osterix. Oral administration of BRE in OVX rats prevented decreases in bone density and strength. By contrast, BRE inhibited adipocyte differentiation of mesenchymal C3H10T1/2 cells and prevented increases in body weight and fat mass in high fat diet fed obese mice, further suggesting the dual effects of BRE on anti-adipogenesis and pro-osteogenesis. UPLC analysis identified cyanidin-3-O-glucoside and peonidin-3-O-glucoside as main anti-adipogenic effectors but not for pro-osteogenic induction. In mechanism studies, BRE selectively stimulated Wnt-driven luciferase activities. BRE treatment also induced Wnt-specific target genes such as Axin2, WISP2, and Cyclin D1. Taken together, these data suggest that BRE is a potentially useful ingredient to protect against age related osteoporosis and diet induced obesity.

Numerical simulation of electrically stimulated osteogenesis in dental implants.

PubMed

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.

Role of hepatocyte growth factor in the development of dendritic cells from CD34+ bone marrow cells.

PubMed

Ovali, E; Ratip, S; Kibaroglu, A; Tekelioglu, Y; Cetiner, M; Karti, S; Aydin, F; Bayik, M; Akoglu, T

2000-05-01

Hepatocyte growth factor (HGF) is known to augment the effects of stem cell factor, interleukin-3, granulocyte-macrophage colony-stimulating factor (GM-CSF), erythropoetin, and granulocyte colony-stimulating factor, all of which are involved in hematopoiesis. HGF is also known to have a role in immune responses. The aim of this study was to investigate whether HGF is involved in the development of dendritic cells (DC) from CD34+ bone marrow cells. CD34+ cells obtained from three healthy donors were incubated in various combinations of HGF, GM-CSF, and tumor necrosis factor (TNF) for 12 days. Developing cell populations were analyzed for surface markers, morphology and functional capacities by flow cytometry, light microscopy and mixed lymphocyte reaction, respectively. Incubation with HGF alone generated greater number of dendritic cells from CD34+ bone marrow cells than incubation with GM-CSF, or a combination of GM-CSF with TNF. HGF was also found to potentiate the effect of GM-CSF on DC and monocyte development. The effects of HGF were inhibited by the concurrent use of TNF. HGF appears to be a significant factor in the development of dendritic cells from CD34+ bone marrow cells.

The fast track to canonical Wnt signaling in MC3T3-E1 cells protected by substance P against serum deprivation-induced apoptosis.

PubMed

Yang, Jianguo; Nie, Jiping; Fu, Su; Liu, Song; Wu, Jianqun; Cui, Liang; Zhang, Yongtao; Yu, Bin

2017-01-01

The canonical Wnt pathway is vital to bone physiology by increasing bone mass through elevated osteoblast survival. Although investigated extensively in stem cells, its role in osteoblastic MC3T3-E1 cells has not been completely determined. To explore how this pathway is regulated by different conditions, we assessed the anti-apoptotic effects of substance P on the canonical Wnt pathway in MC3T3-E1 cells by treating cells with serum deprivation or serum starving with "substance P," a neuropeptide demonstrated to promote bone growth and stimulate Wnt signaling. The results showed that serum deprivation both induced apoptosis and activated Wnt signal transduction while substance P further stimulated the Wnt pathway via the NK-1 receptor but protected the cells from apoptotic death. Fast-tracking of Wnt signaling by substance P was also noted. These results indicate that nutritional deprivation and substance P synergistically activated the canonical Wnt pathway, a finding that helps to reveal the role of Wnt signaling in bone physiology affected by nutritional deprivation and neuropeptide substance P. © 2016 International Federation for Cell Biology.

Surgical intervention of complex endo-perio lesions.

PubMed

Adcock, John E; Bright, David

2007-08-01

Complex endo-perio lesions are infrequent, but pose treatment dilemmas. The lesions are complex with bone loss involving adjacent teeth that are not part of the initial endodontic lesion. The aggressive bone loss is not clearly understood and apparently has some differences from the usual apical periodontitis.

Growing B Lymphocytes in a Three-Dimensional Culture System

NASA Technical Reports Server (NTRS)

Wu, J. H. David; Bottaro, Andrea

2010-01-01

A three-dimensional (3D) culture system for growing long-lived B lymphocytes has been invented. The capabilities afforded by the system can be expected to expand the range of options for immunological research and related activities, including testing of immunogenicity of vaccine candidates in vitro, generation of human monoclonal antibodies, and immunotherapy. Mature lymphocytes, which are the effectors of adaptive immune responses in vertebrates, are extremely susceptible to apoptotic death, and depend on continuous reception of survival-inducing stimulation (in the forms of cytokines, cell-to-cell contacts, and antigen receptor signaling) from the microenvironment. For this reason, efforts to develop systems for long-term culture of functional, non-transformed and non-activated mature lymphocytes have been unsuccessful until now. The bone-marrow microenvironment supports the growth and differentiation of many hematopoietic lineages, in addition to B-lymphocytes. Primary bone-marrow cell cultures designed to promote the development of specific cell types in vitro are highly desirable experimental systems, amenable to manipulation under controlled conditions. However, the dynamic and complex network of stromal cells and insoluble matrix proteins is disrupted in prior plate- and flask-based culture systems, wherein the microenvironments have a predominantly two-dimensional (2D) character. In 2D bone-marrow cultures, normal B-lymphoid cells become progressively skewed toward precursor B-cell populations that do not retain a normal immunophenotype, and such mature B-lymphocytes as those harvested from the spleen or lymph nodes do not survive beyond several days ex vivo in the absence of mitogenic stimulation. The present 3D culture system is a bioreactor that contains highly porous artificial scaffolding that supports the long-term culture of bone marrow, spleen, and lymph-node samples. In this system, unlike in 2D culture systems, B-cell subpopulations developing within 3D cultures that have been modified to foster lymphopoiesis retain an immunophenotype that closely recapitulates cells in fresh bone marrow harvests. The 3D culture system has been found to be capable of supporting long-lived (8 weeks) populations of B and T lymphocytes from peripheral lymphoid organs, in the absence of activation signals, to an extent not achievable by conventional culture techniques. Interestingly, it has been found that 3D-culture B cells display a phenotype that has characteristics of both B1a and B2 cells. These promising preliminary observations suggest that the 3D culture system could be used with success in the study of peripheral-B-lymphocyte biology and in the development of biotechnological techniques and processes.

A New Regulator of Osteoclastogenesis: Estrogen Response Element–Binding Protein in Bone

PubMed Central

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

Intraoral conversion of occlusal force to electricity and magnetism by biting of piezoelectric elements.

PubMed

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.

2-(trimethylammonium) ethyl (R)-3-methoxy-3-oxo-2-stearamidopropyl phosphate suppresses osteoclast maturation and bone resorption by targeting macrophage-colony stimulating factor signaling.

PubMed

Park, So Jeong; Park, Doo Ri; Bhattarai, Deepak; Lee, Kyeong; Kim, Jaesang; Bae, Yun Soo; Lee, Soo Young

2014-08-01

2-(Trimethylammonium) ethyl (R)-3-methoxy-3-oxo-2-stearamidopropyl phosphate [(R)-TEMOSPho], a derivative of an organic chemical identified from a natural product library, promotes highly efficient megakaryopoiesis. Here, we show that (R)-TEMOSPho blocks osteoclast maturation from progenitor cells of hematopoietic origin, as well as blocking the resorptive function of mature osteoclasts. The inhibitory effect of (R)-TEMOSPho on osteoclasts was due to a disruption of the actin cytoskeleton, resulting from impaired downstream signaling of c-Fms, a receptor for macrophage-colony stimulating factor linked to c-Cbl, phosphoinositol-3-kinase (PI3K), Vav3, and Rac1. In addition, (R)-TEMOSPho blocked inflammation-induced bone destruction by reducing the numbers of osteoclasts produced in mice. Thus, (R)-TEMOSPho may represent a promising new class of antiresorptive drugs for the treatment of bone loss associated with increased osteoclast maturation and activity.

Electrical stimulation on joint contracture: an experiment in rat model with direct current.

PubMed

Akai, M; Shirasaki, Y; Tateishi, T

1997-04-01

To examine whether electrical stimulation could decrease the degree of joint stiffness in a rat lower extremity model. Rat knee joints were surgically immobilized in a flexed position for 3 weeks. Two groups of rats were stimulated with 20 microA and 50 microA constant direct current. Another group had surgical intervention and sham electrodes without electricity. The hind leg was extirpated and prepared for a sample with the femur-knee joint-tibia unit. Recording the knee flexion angle with extension torque, the degree of joint contracture was assessed biomechanically by measuring the bone-joint-bone sample as a cantilever. Measurement was performed with (1) spectral analysis of transfer function measurement using random mechanical noise with frequency range from 1 to 50Hz, and (2) dynamic stiffness and loss tangent with steady-state sinusoidal excitation (11 and 35Hz). The results showed that no significant difference or trend was found in vibration analysis among three groups. However, spectral analysis of transfer function measurement revealed more deformation against load, and more viscous nature in the stimulation groups, especially in low frequency band, than in the sham group. Electrical stimulation with constant direct current has a possibility of reducing the degree of joint contracture.

[Bone marrow stromal damage mediated by immune response activity].

PubMed

Vojinović, J; Kamenov, B; Najman, S; Branković, Lj; Dimitrijević, H

1994-01-01

The aim of this work was to estimate influence of activated immune response on hematopoiesis in vitro, using the experimental model of BCG immunized BALB/c mice and in patients with chronic immunoactivation: long-lasting infections, autoimmunity or malignancy. We correlated changes in long term bone marrow cultures (Dexter) and NBT reduction with appearance of anemia in patients and experimental model of immunization by BCG. Increased spontaneous NBT reduction pointed out role of macrophage activation in bone marrow stroma damage. Long-term bone marrow cultures showed reduced number of hematopoietic cells, with predomination of fibroblasts and loss of fat cells. This results correlated with anemia and leucocytosis with stimulated myelopoiesis in peripheral blood. Activation of immune response, or acting of any agent that directly changes extracellular matrix and cellularity of bone marrow, may result in microenviroment bone marrow damage that modify hematopoiesis.

Osteoblastic mesenchymal stem cell sheet combined with Choukroun platelet-rich fibrin induces bone formation at an ectopic site.

PubMed

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.

Anabolic actions of Notch on mature bone

PubMed Central

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

Scaffold Design for Bone Regeneration

PubMed Central

Polo-Corrales, Liliana; Latorre-Esteves, Magda; Ramirez-Vick, Jaime E.

2014-01-01

The use of bone grafts is the standard to treat skeletal fractures, or to replace and regenerate lost bone, as demonstrated by the large number of bone graft procedures performed worldwide. The most common of these is the autograft, however, its use can lead to complications such as pain, infection, scarring, blood loss, and donor-site morbidity. The alternative is allografts, but they lack the osteoactive capacity of autografts and carry the risk of carrying infectious agents or immune rejection. Other approaches, such as the bone graft substitutes, have focused on improving the efficacy of bone grafts or other scaffolds by incorporating bone progenitor cells and growth factors to stimulate cells. An ideal bone graft or scaffold should be made of biomaterials that imitate the structure and properties of natural bone ECM, include osteoprogenitor cells and provide all the necessary environmental cues found in natural bone. However, creating living tissue constructs that are structurally, functionally and mechanically comparable to the natural bone has been a challenge so far. This focus of this review is on the evolution of these scaffolds as bone graft substitutes in the process of recreating the bone tissue microenvironment, including biochemical and biophysical cues. PMID:24730250

Use of ossein-hydroxyapatite complex in the prevention of bone loss: a review.

PubMed

Castelo-Branco, C; Dávila Guardia, J

2015-02-01

The ossein-hydroxyapatite complex (OHC) is a microcrystalline form of calcium which provides a number of additional minerals (magnesium, phosphorus, potassium, zinc), and proteins (osteocalcin, type I collagen, type I insulin growth factor I and II, transforming growth factor beta) associated with bone metabolism. The objective of this review is to examine the role of OHC in preventing bone loss in different conditions. A review of clinical trials assessing the relationship between OHC and bone loss was made using the following data sources: Medline (from 1966 to December 2013), the Cochrane Controlled Clinical Trials Register, Embase (up to December 2013), contact with companies marketing the supplements studied, and reference lists. Different randomized, clinical trials and meta-analysis suggest that OHC is more effective than calcium supplements in maintaining bone mass in postmenopausal women and in different conditions related to bone loss. In addition, OHC improves pain symptoms and accelerates fracture consolidation in patients with osteopenia or osteoporosis. The ossein-hydroxyapatite complex is significantly more effective in preventing bone loss than calcium carbonate.

Effects of porcine 25 kDa amelogenin and its proteolytic derivatives on bone sialoprotein expression.

PubMed

Nakayama, Y; Yang, L; Mezawa, M; Araki, S; Li, Z; Wang, Z; Sasaki, Y; Takai, H; Nakao, S; Fukae, M; Ogata, Y

2010-10-01

Amelogenins are hydrophobic proteins that are the major component of developing enamel. Enamel matrix derivative has been used for periodontal regeneration. Bone sialoprotein is an early phenotypic marker of osteoblast differentiation. In this study, we examined the ability of porcine amelogenins to regulate bone sialoprotein transcription. To determine the molecular basis of the transcriptional regulation of the bone sialoprotein gene by amelogenins, we conducted northern hybridization, transient transfection analyses and gel mobility shift assays using the osteoblast-like ROS 17/2.8 cells. Amelogenins (100 ng/mL) up-regulated bone sialoprotein mRNA at 3 h, with maximal mRNA expression occurring at 12 h (25 and 20 kDa) and 6 h (13 and 6 kDa). Amelogenins (100 ng/mL, 12 h) increased luciferase activities in pLUC3 (nucleotides -116 to +60), and 6 kDa amelogenin up-regulated pLUC4 (nucleotides -425 to +60) activity. The tyrosine kinase inhibitor inhibited amelogenin-induced luciferase activities, whereas the protein kinase A inhibitor abolished 25 kDa amelogenin-induced bone sialoprotein transcription. The effects of amelogenins were abrogated by 2-bp mutations in the fibroblast growth factor 2 response element (FRE). Gel-shift assays with radiolabeled FRE, homeodomain-protein binding site (HOX) and transforming growth factor-beta1 activation element (TAE) double-strand oligonucleotides revealed increased binding of nuclear proteins from amelogenin-stimulated ROS 17/2.8 cells at 3 h (25 and 13 kDa) and 6 h (20 and 6 kDa). These results demonstrate that porcine 25 kDa amelogenin and its proteolytic derivatives stimulate bone sialoprotein transcription by targeting FRE, HOX and TAE in the bone sialoprotein gene promoter, and that full-length amelogenin and amelogenin cleavage products are able to regulate bone sialoprotein transcription via different signaling pathways. (c) 2010 John Wiley & Sons A/S.

Follicle-stimulating hormone and bioavailable estradiol are less important than weight and race in determining bone density in younger postmenopausal women

PubMed Central

Preisser, J. S.; Hammett-Stabler, C. A.; Renner, J. B.; Rubin, J.

2011-01-01

Summary The association between follicle-stimulating hormone (FSH) and bone density was tested in 111 postmenopausal women aged 50–64 years. In the multivariable analysis, weight and race were important determinants of bone mineral density. FSH, bioavailable estradiol, and other hormonal variables did not show statistically significant associations with bone density at any site. Introduction FSH has been associated with bone density loss in animal models and longitudinal studies of women. Most of these analyses have not considered the effect of weight or race. Methods We tested the association between FSH and bone density in younger postmenopausal women, adjusting for patient-related factors. In 111 postmenopausal women aged 50–64 years, areal bone mineral density (BMD) was measured at the lumbar spine, femoral neck, total hip, and distal radius using dual-energy X-ray absorptiometry, and volumetric BMD was measured at the distal radius using peripheral quantitative computed tomography (pQCT). Height, weight, osteoporosis risk factors, and serum hormonal factors were assessed. Results FSH inversely correlated with weight, bioavailable estradiol, areal BMD at the lumbar spine and hip, and volumetric BMD at the ultradistal radius. In the multivariable analysis, no hormonal variable showed a statistically significant association with areal BMD at any site. Weight was independently associated with BMD at all central sites (p<0.001), but not with BMD or pQCT measures at the distal radius. Race was independently associated with areal BMD at all sites (p≤0.008) and with cortical area at the 33% distal radius (p=0.004). Conclusions Correlations between FSH and bioavailable estradiol and BMD did not persist after adjustment for weight and race in younger postmenopausal women. Weight and race were more important determinants of bone density and should be included in analyses of hormonal influences on bone. PMID:21125395

Spaceflight alters immune cell function and distribution

NASA Technical Reports Server (NTRS)

Sonnenfeld, Gerald; Mandel, Adrian D.; Konstantinova, Irina V.; Berry, Wallace D.; Taylor, Gerald R.; Lesniak, A. T.; Fuchs, Boris B.; Rakhmilevich, Alexander L.

1992-01-01

Experiments are described which were performed onboard Cosmos 2044 to determine spaceflight effects on immunologically important cell function and distribution. Results indicate that bone marrow cells from flown and suspended rats exhibited a decreased response to a granulocyte/monocyte colony-stimulating factor compared with the bone marrow cells from control rats. Bone marrow cells showed an increase in the percentage of cells expressing markers for helper T-cells in the myelogenous population and increased percentages of anti-asialo granulocyte/monocyte-1-bearing interleulin-2 receptor bearing pan T- and helper T-cells in the lymphocytic population.