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Sample records for affecting bone formation

  1. In vivo loading increases mechanical properties of scaffold by affecting bone formation and bone resorption rates.

    PubMed

    Roshan-Ghias, Alireza; Lambers, Floor M; Gholam-Rezaee, Mehdi; Müller, Ralph; Pioletti, Dominique P

    2011-12-01

    A successful bone tissue engineering strategy entails producing bone-scaffold constructs with adequate mechanical properties. Apart from the mechanical properties of the scaffold itself, the forming bone inside the scaffold also adds to the strength of the construct. In this study, we investigated the role of in vivo cyclic loading on mechanical properties of a bone scaffold. We implanted PLA/β-TCP scaffolds in the distal femur of six rats, applied external cyclic loading on the right leg, and kept the left leg as a control. We monitored bone formation at 7 time points over 35 weeks using time-lapsed micro-computed tomography (CT) imaging. The images were then used to construct micro-finite element models of bone-scaffold constructs, with which we estimated the stiffness for each sample at all time points. We found that loading increased the stiffness by 60% at 35 weeks. The increase of stiffness was correlated to an increase in bone volume fraction of 18% in the loaded scaffold compared to control scaffold. These changes in volume fraction and related stiffness in the bone scaffold are regulated by two independent processes, bone formation and bone resorption. Using time-lapsed micro-CT imaging and a newly-developed longitudinal image registration technique, we observed that mechanical stimulation increases the bone formation rate during 4-10 weeks, and decreases the bone resorption rate during 9-18 weeks post-operatively. For the first time, we report that in vivo cyclic loading increases mechanical properties of the scaffold by increasing the bone formation rate and decreasing the bone resorption rate.

  2. Factors stimulating bone formation.

    PubMed

    Lind, M; Bünger, C

    2001-10-01

    The aim of this review is to describe major approaches for stimulating bone healing and to review other factors affecting bone healing. Spinal bone fusion after surgery is a demanding process requiring optimal conditions for clinical success. Bone formation and healing can be enhanced through various methods. Experimental studies have revealed an array of stimulative measures. These include biochemical stimulation by use of hormones and growth factors, physical stimulation through mechanical and electromagnetic measures, and bone grafting by use of bone tissue or bone substitutes. Newer biological techniques such as stem cell transplantation and gene therapy can also be used to stimulate bone healing. Apart from bone transplantation, clinical experience with the many stimulation modalities is limited. Possible areas for clinical use of these novel methods are discussed.

  3. Low dose pioglitazone does not affect bone formation and resorption markers or bone mineral density in streptozocin-induced diabetic rats.

    PubMed

    Tsirella, E; Mavrakanas, T; Rager, O; Tsartsalis, S; Kallaras, K; Kokkas, B; Mironidou-Tzouveleki, M

    2012-04-01

    Our study aims to investigate the effect of a low-dose pioglitazone regimen on bone mineral density and bone formation-resorption markers in control and diabetic rats. Wistar rats were divided into 4 groups: non-diabetic controls, control rats receiving pioglitazone (3 mg/kg), streptozocin-treated diabetic rats (50 mg/kg), diabetic rats treated with pioglitazone (3 mg/kg). The duration of the experiment was 8 weeks. Diabetes in our rats was associated with weight loss, increased urinary calcium excretion and reduced plasma osteocalcin levels. Diabetes mellitus did not affect bone mineral density. Pioglitazone administration had no impact on bone formation and resorption markers levels and did not modify bone mineral density in the four studied groups. Pioglitazone at the 3 mg/kg dose was not associated with significant skeletal complications in our experimental model.

  4. Factors affecting bone growth.

    PubMed

    Gkiatas, Ioannis; Lykissas, Marios; Kostas-Agnantis, Ioannis; Korompilias, Anastasios; Batistatou, Anna; Beris, Alexandros

    2015-02-01

    Bone growth and development are products of the complex interactions of genetic and environmental factors. Longitudinal bone growth depends on the growth plate. The growth plate has 5 different zones-each with a different functional role-and is the final target organ for longitudinal growth. Bone length is affected by several systemic, local, and mechanical factors. All these regulation systems control the final length of bones in a complicated way. Despite its significance to bone stability, bone growth in width has not been studied as extensively as longitudinal bone growth. Bone growth in width is also controlled by genetic factors, but mechanical loading regulates periosteal apposition. In this article, we review the most recent data regarding bone growth from the embryonic age and analyze the factors that control bone growth. An understanding of this complex system is important in identifying metabolic and developmental bone diseases and fracture risk.

  5. Reciprocal Interactions between Multiple Myeloma Cells and Osteoprogenitor Cells Affect Bone Formation and Tumor Growth

    DTIC Science & Technology

    2015-12-01

    frequent occurrence of tumour metastases in bone (discussed later), as well as serious infections such as tuberculosis involving this tissue before...as shown in Figure 3 below. Our next step was to use a TurboRed (RFP)-containing plasmid packaged into a lentivirus to infect the cells and...Institute of Technology, Cambridge, MA 02139; dDepartment of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Harvard Medical

  6. Dilatational band formation in bone

    PubMed Central

    Poundarik, Atharva A.; Diab, Tamim; Sroga, Grazyna E.; Ural, Ani; Boskey, Adele L.; Gundberg, Caren M.; Vashishth, Deepak

    2012-01-01

    Toughening in hierarchically structured materials like bone arises from the arrangement of constituent material elements and their interactions. Unlike microcracking, which entails micrometer-level separation, there is no known evidence of fracture at the level of bone’s nanostructure. Here, we show that the initiation of fracture occurs in bone at the nanometer scale by dilatational bands. Through fatigue and indentation tests and laser confocal, scanning electron, and atomic force microscopies on human and bovine bone specimens, we established that dilatational bands of the order of 100 nm form as ellipsoidal voids in between fused mineral aggregates and two adjacent proteins, osteocalcin (OC) and osteopontin (OPN). Laser microdissection and ELISA of bone microdamage support our claim that OC and OPN colocalize with dilatational bands. Fracture tests on bones from OC and/or OPN knockout mice (OC−/−, OPN−/−, OC-OPN−/−;−/−) confirm that these two proteins regulate dilatational band formation and bone matrix toughness. On the basis of these observations, we propose molecular deformation and fracture mechanics models, illustrating the role of OC and OPN in dilatational band formation, and predict that the nanometer scale of tissue organization, associated with dilatational bands, affects fracture at higher scales and determines fracture toughness of bone. PMID:23129653

  7. Bone formation: roles of genistein and daidzein

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bone remodeling consists of a balance between bone formation by osteoblasts and bone resorption by osteoclasts. Osteoporosis is the result of increased bone resorption and decreased bone formation causing a decreased bone mass density, loss of bone microarchitecture, and an increased risk of fractu...

  8. Targeted disruption of TGFBI in mice reveals its role in regulating bone mass and bone size through periosteal bone formation.

    PubMed

    Yu, Hongrun; Wergedal, Jon E; Zhao, Yongliang; Mohan, Subburaman

    2012-07-01

    Transforming growth factor-beta induced (TGFBI) and periostin are two closely related proteins in structure as well as in function. A previous study found that periostin positively regulates bone size. Here, we hypothesize that TGFBI has a similar function in bone development. To test this hypothesis, we employed TGFBI-deficient mice, which were generated by targeted disruption of the TGFBI gene. We bred these mice with C57BL/6J mice to generate homozygous TGFBI-deficient (TGFBI(-/-)) mice and homozygous wild-type littermates. All mice were raised to 12 weeks of age. Bone mass parameters were determined by PIXImus and micro-CT, bone strength parameters by three-point bending, and bone formation and resorption parameters by histomorphometry. We found that targeted disruption of TGFBI led to reduced body size, bone mass, bone size, and bone strength. This indicates that, like periostin, TGFBI also positively regulates bone size and that changes in bone size affect bone strength. Furthermore, there was also a significant decrease in periosteal, but not endosteal, bone formation rate of cortical bone in TGFBI(-/-) mice, suggesting that the observed effect of TGFBI on bone mass and bone size was largely caused by the effect of TGFBI on periosteal bone formation.

  9. Effect of spaceflight on periosteal bone formation in rats

    NASA Technical Reports Server (NTRS)

    Wronski, T. J.; Morey, E. R.

    1983-01-01

    Male Wistar rats were placed in orbit for 18.5 days aboard the Soviet COSMOS 1129 biological satellite. Tetracycline was administered before and after spaceflight to label areas of bone formation. An inhibition of periosteal bone formation occurred during spaceflight in the tibial and humeral diaphyses, but this defect was corrected during the postflight period. The increased extent of arrest lines at these skeletal sites suggested that periosteal bone formation may have even ceased during spaceflight. The rib exhibited a small but nonsignificant decrease in periosteal bone formation. Endosteal bone resorption was not affected markedly by spaceflight conditions. The observed inhibition of periosteal bone formation may be a result of mechanical unloading, but endocrine factors cannot be ruled out.

  10. [Cytokines in bone diseases. Wnt signal and excessive bone formation].

    PubMed

    Hosoi, Takayuki

    2010-10-01

    Wnt signal has been known to play various roles in many organ from the beginning of embryogensis. Its role in bone metabolism has also been investigated and established. Lipoprotein receptor-related protein 5 (LRP5) is one of the important molecules in wnt signal pathway whose point mutations are related to both bone loss and excessive bone formation. Wnt signal is involved in the action of sclerostin which was found as a gene for osteosclerosis, one of the diseases of excessive bone formation. Wnt signal is keeping the position as an important research target for normal and pathological bone formation.

  11. Evidence for arrested bone formation during spaceflight

    NASA Technical Reports Server (NTRS)

    Turner, R. T.; Bobyn, J. D.; Duvall, P.; Morey, E. R.; Baylink, D. J.; Spector, M.

    1982-01-01

    Addressing the question of whether the bone formed in space is unusual, the morphology of bone made at the tibial diaphysis of rats before, during, and after spaceflight is studied. Evidence of arrest lines in the bone formed in space is reported suggesting that bone formation ceases along portions of the periosteum during spaceflight. Visualized by microradiography, the arrest lines are shown to be less mineralized than the surrounding bone matrix. When viewed by scanning electron microscopy, it is seen that bone fractures more readily at the site of an arrest line. These observations are seen as suggesting that arrest lines are a zone of weakness and that their formation may result in decreased bone strength in spite of normalization of bone formation after flight. The occurrence, location, and morphology of arrest lines are seen as suggesting that they are a visible result of the phenomenon of arrested bone formation.

  12. Inhibition of bone formation during space flight

    NASA Technical Reports Server (NTRS)

    Morey, E. R.; Baylink, D. J.

    1978-01-01

    Parameters of bone formation and resorption were measured in rats orbited for 19.5 days aboard the Soviet Cosmos 782 biological satellite. The most striking effects were on bone formation. During flight, rats formed significantly less periosteal bone than did control rats on the ground. An arrest line at both the periosteum and the endosteum of flight animals suggests that a complete cecessation of bone growth occurred. During a 26-day postflight period, the defect in bone formation was corrected. No significant changes in bone resorption were observed.

  13. Leptin regulates bone formation via the sympathetic nervous system

    NASA Technical Reports Server (NTRS)

    Takeda, Shu; Elefteriou, Florent; Levasseur, Regis; Liu, Xiuyun; Zhao, Liping; Parker, Keith L.; Armstrong, Dawna; Ducy, Patricia; Karsenty, Gerard

    2002-01-01

    We previously showed that leptin inhibits bone formation by an undefined mechanism. Here, we show that hypothalamic leptin-dependent antiosteogenic and anorexigenic networks differ, and that the peripheral mediators of leptin antiosteogenic function appear to be neuronal. Neuropeptides mediating leptin anorexigenic function do not affect bone formation. Leptin deficiency results in low sympathetic tone, and genetic or pharmacological ablation of adrenergic signaling leads to a leptin-resistant high bone mass. beta-adrenergic receptors on osteoblasts regulate their proliferation, and a beta-adrenergic agonist decreases bone mass in leptin-deficient and wild-type mice while a beta-adrenergic antagonist increases bone mass in wild-type and ovariectomized mice. None of these manipulations affects body weight. This study demonstrates a leptin-dependent neuronal regulation of bone formation with potential therapeutic implications for osteoporosis.

  14. Hormonal and Local Regulation of Bone Formation.

    ERIC Educational Resources Information Center

    Canalis, Ernesto

    1985-01-01

    Reviews effects of hormones, systemic factors, and local regulators on bone formation. Identifies and explains the impact on bone growth of several hormones as well as the components of systemic and local systems. Concentrates on bone collagen and DNA synthesis. (Physicians may earn continuing education credit by completing an appended test). (ML)

  15. [Fluoride effect on bone formation--an overview].

    PubMed

    Mohr, H

    1990-12-01

    The purpose of this review is to evaluate our present knowledge of fluoride effect on bone formation on basis of the literature. It is likely that fluoride affects the remodelling processes of the skeleton as well as growth related bone formation. During bone remodelling the amount of bone and osteoid tissue is increased by alteration of the balance between resorption and formation. This finding may be accompagnied by impaired mineralization. In studies of fluoride effect on growth related bone formation a number of quantitative histologic alterations have been observed. These include reduction in epiphyseal plate thickness and changes in cellular morphology as well as a retardation of mineralization. The pathogenetic mechanisms behind the observed effects and the variation in tissue response are still unexplained. Fluoride may have a direct cellular effect causing disturbances in cell morphology and metabolism, but the effects may also involve local supracellular mechanisms as well as the general homeostasis of the individual.

  16. Affective Disorders, Bone Metabolism, and Osteoporosis

    PubMed Central

    2013-01-01

    The nature of the relationship between affective disorders, bone mineral density (BMD), and bone metabolism is unresolved, although there is growing evidence that many medications used to treat affective disorders are associated with low BMD or alterations in neuroendocrine systems that influence bone turnover. The objective of this review is to describe the current evidence regarding the association of unipolar and bipolar depression with BMD and indicators of bone metabolism, and to explore potential mediating and confounding influences of those relationships. The majority of studies of unipolar depression and BMD indicate that depressive symptoms are associated with low BMD. In contrast, evidence regarding the relationship between bipolar depression and BMD is inconsistent. There is limited but suggestive evidence to support an association between affective disorders and some markers of bone turnover. Many medications used to treat affective disorders have effects on physiologic systems that influence bone metabolism, and these conditions are also associated with a range of health behaviors that can influence osteoporosis risk. Future research should focus on disentangling the pathways linking psychotropic medications and their clinical indications with BMD and fracture risk. PMID:23874147

  17. Space flight and bone formation

    NASA Technical Reports Server (NTRS)

    Doty, St B.

    2004-01-01

    Major physiological changes which occur during spaceflight include bone loss, muscle atrophy, cardiovascular and immune response alterations. When trying to determine the reason why bone loss occurs during spaceflight, one must remember that all these other changes in physiology and metabolism may also have impact on the skeletal system. For bone, however, the role of normal weight bearing is a major concern and we have found no adequate substitute for weight bearing which can prevent bone loss. During the study of this problem, we have learned a great deal about bone physiology and increased our knowledge about how normal bone is formed and maintained. Presently, we do not have adequate ground based models which can mimic the tissue loss that occurs in spaceflight but this condition closely resembles the bone loss seen with osteoporosis. Although a normal bone structure will respond to application of mechanical force and weight bearing by forming new bone, a weakened osteoporotic bone may have a tendency to fracture. The study of the skeletal system during weightless conditions will eventually produce preventative measures and form a basis for protecting the crew during long term space flight. The added benefit from these studies will be methods to treat bone loss conditions which occur here on earth.

  18. Receptor tyrosine kinase inhibition causes simultaneous bone loss and excess bone formation within growing bone in rats

    SciTech Connect

    Nurmio, Mirja; Joki, Henna; Kallio, Jenny; Maeaettae, Jorma A.; Vaeaenaenen, H. Kalervo; Toppari, Jorma; Jahnukainen, Kirsi; Laitala-Leinonen, Tiina

    2011-08-01

    During postnatal skeletal growth, adaptation to mechanical loading leads to cellular activities at the growth plate. It has recently become evident that bone forming and bone resorbing cells are affected by the receptor tyrosine kinase (RTK) inhibitor imatinib mesylate (STI571, Gleevec (registered)) . Imatinib targets PDGF, ABL-related gene, c-Abl, c-Kit and c-Fms receptors, many of which have multiple functions in the bone microenvironment. We therefore studied the effects of imatinib in growing bone. Young rats were exposed to imatinib (150 mg/kg on postnatal days 5-7, or 100 mg/kg on postnatal days 5-13), and the effects of RTK inhibition on bone physiology were studied after 8 and 70 days (3-day treatment), or after 14 days (9-day treatment). X-ray imaging, computer tomography, histomorphometry, RNA analysis and immunohistochemistry were used to evaluate bone modeling and remodeling in vivo. Imatinib treatment eliminated osteoclasts from the metaphyseal osteochondral junction at 8 and 14 days. This led to a resorption arrest at the growth plate, but also increased bone apposition by osteoblasts, thus resulting in local osteopetrosis at the osteochondral junction. The impaired bone remodelation observed on day 8 remained significant until adulthood. Within the same bone, increased osteoclast activity, leading to bone loss, was observed at distal bone trabeculae on days 8 and 14. Peripheral quantitative computer tomography (pQCT) and micro-CT analysis confirmed that, at the osteochondral junction, imatinib shifted the balance from bone resorption towards bone formation, thereby altering bone modeling. At distal trabecular bone, in turn, the balance was turned towards bone resorption, leading to bone loss. - Research Highlights: > 3-Day imatinib treatment. > Causes growth plate anomalies in young rats. > Causes biomechanical changes and significant bone loss at distal trabecular bone. > Results in loss of osteoclasts at osteochondral junction.

  19. Effect of psoralen on bone formation.

    PubMed

    Wong, Ricky W K; Rabie, A Bakr M

    2011-02-01

    To compare the amount of new bone and bone cells produced by psoralen in collagen matrix to that produced by collagen matrix in vivo. Eighteen bone defects, 5 mm by 10 mm were created in the parietal bone of nine New Zealand White rabbits. Six defects were grafted with psoralen mixed with collagen matrix. Six defects were grafted with collagen matrix alone (negative control--collagen) and six were left empty (negative control--empty). Animals were killed on day 14 and the defects were dissected and prepared for histological assessment. Quantitative analysis of new bone formation and bone cells were made on 100 sections (50 sections for each group) using image analysis. A total of 454% more new bone was present in defects grafted with psoralen in collagen matrix than those grafted with collagen matrix. No bone was formed in the negative control--empty group. The amount of bone forming osteoblasts was also significantly greater in the psoralen group than the negative control--collagen group. Psoralen in collagen matrix has the effect of increasing new bone formation locally in vivo. Psoralen in collagen matrix can be developed as a bone graft material.

  20. Molecular mechanisms of bone formation in spondyloarthritis.

    PubMed

    González-Chávez, Susana Aideé; Quiñonez-Flores, Celia María; Pacheco-Tena, César

    2016-07-01

    Spondyloarthritis comprise a group of inflammatory rheumatic diseases characterized by its association to HLA-B27 and the presence of arthritis and enthesitis. The pathogenesis involves both an inflammatory process and new bone formation, which eventually lead to ankylosis of the spine. To date, the intrinsic mechanisms of the pathogenic process have not been fully elucidated, and our progress is remarkable in the identification of therapeutic targets to achieve the control of the inflammatory process, yet our ability to inhibit the excessive bone formation is still insufficient. The study of new bone formation in spondyloarthritis has been mostly conducted in animal models of the disease and only few experiments have been done using human biopsies. The deregulation and overexpression of molecules involved in the osteogenesis process have been observed in bone cells, mesenchymal cells, and fibroblasts. The signaling associated to the excessive bone formation is congruent with those involved in the physiological processes of bone remodeling. Bone morphogenetic proteins and Wnt pathways have been found deregulated in this disease; however, the cause for uncontrolled stimulation remains unknown. Mechanical stress appears to play an important role in the pathological osteogenesis process; nevertheless, the association of other important factors, such as the presence of HLA-B27 and environmental factors, remains uncertain. The present review summarizes the experimental findings that describe the signaling pathways involved in the new bone formation process in spondyloarthritis in animal models and in human biopsies. The role of mechanical stress as the trigger of these pathways is also reviewed.

  1. A cellular automata model of bone formation.

    PubMed

    Van Scoy, Gabrielle K; George, Estee L; Opoku Asantewaa, Flora; Kerns, Lucy; Saunders, Marnie M; Prieto-Langarica, Alicia

    2017-04-01

    Bone remodeling is an elegantly orchestrated process by which osteocytes, osteoblasts and osteoclasts function as a syncytium to maintain or modify bone. On the microscopic level, bone consists of cells that create, destroy and monitor the bone matrix. These cells interact in a coordinated manner to maintain a tightly regulated homeostasis. It is this regulation that is responsible for the observed increase in bone gain in the dominant arm of a tennis player and the observed increase in bone loss associated with spaceflight and osteoporosis. The manner in which these cells interact to bring about a change in bone quality and quantity has yet to be fully elucidated. But efforts to understand the multicellular complexity can ultimately lead to eradication of metabolic bone diseases such as osteoporosis and improved implant longevity. Experimentally validated mathematical models that simulate functional activity and offer eventual predictive capabilities offer tremendous potential in understanding multicellular bone remodeling. Here we undertake the initial challenge to develop a mathematical model of bone formation validated with in vitro data obtained from osteoblastic bone cells induced to mineralize and quantified at 26 days of culture. A cellular automata model was constructed to simulate the in vitro characterization. Permutation tests were performed to compare the distribution of the mineralization in the cultures and the distribution of the mineralization in the mathematical models. The results of the permutation test show the distribution of mineralization from the characterization and mathematical model come from the same probability distribution, therefore validating the cellular automata model.

  2. Bone Formation Rate in Experimental Disuse Osteoporosis in Monkeys

    NASA Technical Reports Server (NTRS)

    Cann, Christopher; Young, Donald R.

    1976-01-01

    Specific mechanisms underlying weightless and hypodynamic bone loss are obscure. A principal relationship which must be affected is the balance between bone formation and bone resorption rates. In order to better define the influence of those parameters on bone loss, and also to develop measurements in other species as a useful adjunct to human research, studies were undertaken with experimental monkeys. Tests were conducted with a total of 6 adult male monkeys, weighing 10-13 kg, and approximately 10-12 yrs. of age to evaluate specifically bone formation rate during the development of disuse osteoporosis and osteopenia. Three animals were restrained in a semi-recumbent position for six months; three animals served as normal caged controls. Food intake (Purina) was held relatively constant at 200g/day for each animal. Using a Norland Bone Mineral Analyzer, bone mineral losses of 3.5 to 6% were seen in the mid-shaft of the tibia and in the distal radius. Bone loss was confirmed radiographically, with observation of thinning of the proximal tibial cortex and trabeculae in the calcaneus. Bone formation rate was determined using standard Ca-47 kinetics under metabolic balance conditions. After six months of restraint, accretion was 7.2-13.2 mg Ca/kg/day, compared to 3.2-4.1 mg Ca/kg/day in caged controls and 3-8 mg Ca/kg/day in normal adult humans. Fecal and urine calcium was 25-40% higher in restrained animals than in controls. Dietary calcium absorption decreases during restraint, and calcium turnover increases, implying a rise in bone resorption rate concommitant with the observed rise in bone accretion rate. Further studies dealing specifically with bone resorption are underway to define this more fully.

  3. Glucocorticoids suppress bone formation via the osteoclast.

    PubMed

    Kim, Hyun-Ju; Zhao, Haibo; Kitaura, Hideki; Bhattacharyya, Sandip; Brewer, Judson A; Muglia, Louis J; Ross, F Patrick; Teitelbaum, Steven L

    2006-08-01

    The pathogenesis of glucocorticoid-induced (GC-induced) bone loss is unclear. For example, osteoblast apoptosis is enhanced by GCs in vivo, but they stimulate bone formation in vitro. This conundrum suggests that an intermediary cell transmits a component of the bone-suppressive effects of GCs to osteoblasts in the intact animal. Bone remodeling is characterized by tethering of the activities of osteoclasts and osteoblasts. Hence, the osteoclast is a potential modulator of the effect of GCs on osteoblasts. To define the direct impact of GCs on bone-resorptive cells, we compared the effects of dexamethasone (DEX) on WT osteoclasts with those derived from mice with disruption of the GC receptor in osteoclast lineage cells (GRoc-/- mice). While the steroid prolonged longevity of osteoclasts, their bone-degrading capacity was suppressed. The inhibitory effect of DEX on bone resorption reflects failure of osteoclasts to organize their cytoskeleton in response to M-CSF. DEX specifically arrested M-CSF activation of RhoA, Rac, and Vav3, each of which regulate the osteoclast cytoskeleton. In all circumstances GRoc-/- mice were spared the impact of DEX on osteoclasts and their precursors. Consistent with osteoclasts modulating the osteoblast-suppressive effect of DEX, GRoc-/- mice are protected from the steroid's inhibition of bone formation.

  4. Nutritional factors affecting poultry bone health.

    PubMed

    Fleming, Robert H

    2008-05-01

    Outlined are two main current research concerns relating to skeletal disorders in poultry: (a) osteoporosis in egg-laying hens; (b) leg problems caused by rapid bone growth in broiler chickens. Surveys indicate that 30% of caged laying hens suffer at least one lifetime fracture (a severe welfare issue). Modern hybrids produce one egg per d for 50 weeks. For this period 'normal' bone turnover ceases; only medullary bone (MB) is formed, a woven bone type of limited structural value. MB is resorbed for eggshell formation alongside structural bone, leading to increased fracture risk. Avian osteoporosis is reduced by activity and genetic selection but nutrition is also important. Fluoride and vitamin K are beneficial but the timing of nutritional intervention is important. Ca, inorganic P and vitamin D must be adequate and the form of Ca is critical. Limestone fed as particulates benefits skeletal and eggshell quality. In hens fed particulate limestone compared with flour-fed hens the tibiotarsus breaking strength and radiographic density are increased at 56 weeks of age (P<0.01 and P<0.001 respectively) and the number of tartrate-resistant acid phosphatase-positive stained active osteoclasts (mean number per microscopic field) is decreased (P<0.001). In broiler (meat) chickens selection for rapid growth from approximately 50 g to 3 kg in 42 d has inadvertently produced skeletal disorders such as tibial dyschondroplasia, rickets and associated valgus-varus deformities leading to lameness. The beneficial skeletal effects during growth of increased dietary n-3 PUFA:n-6 PUFA (utilising salmon oil) have been demonstrated. Experiments simulating daylight UVB levels have produced beneficial skeletal effects in Ca- and vitamin D-deficient chicks.

  5. Genetic and Transcriptional Control of Bone Formation

    PubMed Central

    Javed, Amjad; Chen, Haiyan; Ghori, Farah Y.

    2010-01-01

    Synopsis An exquisite interplay of developmental cues, transcription factors, coregulatory and signaling proteins support formation of skeletal elements of the jaw during embryogenesis and the dynamic remodeling of alveolar bone in the post-natal life. These molecules promote initial condensation of the mesenchyme, commitment of the mesenchymal progenitor to osteogenic lineage cells, and differentiation of committed osteoblast to mature osteocyte within mineralized bone. Parallel regulatory network promote formation of the functional ostoclast from mononuclear cells to support continuous bone remodeling within the alveolar bone. With an ever expanding list of new regulatory factors, the complexities of the molecular mechanisms that control gene expression in skeletal cells are being further appreciated. This review examines the multifunctional roles of prominent nuclear proteins, cytokines, hormones and paracrine factors that control osteogenesis. PMID:20713262

  6. Experimental adipocere formation: implications for adipocere formation on buried bone.

    PubMed

    Moses, Randolph J

    2012-05-01

    Adipocere, or grave wax (adipo = fat, cere = wax), is a distinctive decomposition product composed primarily of fatty acids (FA) and their alkali salts. FA result from the bacterial enzymatic hydrolysis of body fats. Reactions with ammonia and alkali metals originating from body fluids and pore waters of the depositional environment produce alkali salts of FA (soap). Adipocere formation is generally associated with burial of corpses with ample adipose tissue available. No indications that adipocere can form on defleshed remains have been presented in the literature. At the termination of a long-term bone diagenesis experiment, several samples were found to possess growths of an unknown compound. Gas chromatography-mass spectrometry confirmed that the growths are adipocere. The results herein reveal that adipocere can indeed form on defleshed bones under the right conditions and that even residual adipose and lipids in defleshed bones are sufficient to produce adipocere growth on the surfaces of bone.

  7. Rescuing Loading Induced Bone Formation at Senescence

    PubMed Central

    Srinivasan, Sundar; Ausk, Brandon J.; Prasad, Jitendra; Threet, Dewayne; Bain, Steven D.; Richardson, Thomas S.; Gross, Ted S.

    2010-01-01

    The increasing incidence of osteoporosis worldwide requires anabolic treatments that are safe, effective, and, critically, inexpensive given the prevailing overburdened health care systems. While vigorous skeletal loading is anabolic and holds promise, deficits in mechanotransduction accrued with age markedly diminish the efficacy of readily complied, exercise-based strategies to combat osteoporosis in the elderly. Our approach to explore and counteract these age-related deficits was guided by cellular signaling patterns across hierarchical scales and by the insight that cell responses initiated during transient, rare events hold potential to exert high-fidelity control over temporally and spatially distant tissue adaptation. Here, we present an agent-based model of real-time Ca2+/NFAT signaling amongst bone cells that fully described periosteal bone formation induced by a wide variety of loading stimuli in young and aged animals. The model predicted age-related pathway alterations underlying the diminished bone formation at senescence, and hence identified critical deficits that were promising targets for therapy. Based upon model predictions, we implemented an in vivo intervention and show for the first time that supplementing mechanical stimuli with low-dose Cyclosporin A can completely rescue loading induced bone formation in the senescent skeleton. These pre-clinical data provide the rationale to consider this approved pharmaceutical alongside mild physical exercise as an inexpensive, yet potent therapy to augment bone mass in the elderly. Our analyses suggested that real-time cellular signaling strongly influences downstream bone adaptation to mechanical stimuli, and quantification of these otherwise inaccessible, transient events in silico yielded a novel intervention with clinical potential. PMID:20838577

  8. Osteoblast-derived VEGF regulates osteoblast differentiation and bone formation during bone repair

    PubMed Central

    Hu, Kai; Olsen, Bjorn R.

    2016-01-01

    Osteoblast-derived VEGF is important for bone development and postnatal bone homeostasis. Previous studies have demonstrated that VEGF affects bone repair and regeneration; however, the cellular mechanisms by which it works are not fully understood. In this study, we investigated the functions of osteoblast-derived VEGF in healing of a bone defect. The results indicate that osteoblast-derived VEGF plays critical roles at several stages in the repair process. Using transgenic mice with osteoblast-specific deletion of Vegfa, we demonstrated that VEGF promoted macrophage recruitment and angiogenic responses in the inflammation phase, and optimal levels of VEGF were required for coupling of angiogenesis and osteogenesis in areas where repair occurs by intramembranous ossification. VEGF likely functions as a paracrine factor in this process because deletion of Vegfr2 in osteoblastic lineage cells enhanced osteoblastic maturation and mineralization. Furthermore, osteoblast- and hypertrophic chondrocyte–derived VEGF stimulated recruitment of blood vessels and osteoclasts and promoted cartilage resorption at the repair site during the periosteal endochondral ossification stage. Finally, osteoblast-derived VEGF stimulated osteoclast formation in the final remodeling phase of the repair process. These findings provide a basis for clinical strategies to improve bone regeneration and treat defects in bone healing. PMID:26731472

  9. [New therapies for children affected by bone diseases].

    PubMed

    Ballhausen, Diana; Dépraz, Nuria Garcia; Kern, Ilse; Unger, Sheila; Bonafé, Luisa

    2012-02-22

    Considerable progress has been achieved in recent years in treating children affected by bone diseases. Advances in the understanding of the molecular pathophysiology of genetic bone diseases have led to the development of enzyme replacement therapies for various lysosomal storage diseases, following the breakthrough initiated in treating Gaucher disease. Clinical studies are underway with tailored molecules correcting bone fragility and alleviating chronic bone pain and other manifestations of hypophosphatasia, or promoting growth of long bones in achondroplasia patients. We further report our very encouraging experience with intravenous bisphosphonate treatment in children suffering from secondary osteopenia and the high prevalence of calcium and vitamin D deficits in these severely disabled children.

  10. Distal radial fractures heal by direct woven bone formation

    PubMed Central

    2013-01-01

    Background Descriptions of fracture healing almost exclusively deal with shaft fractures and they often emphasize endochondral bone formation. In reality, most fractures occur in metaphyseal cancellous bone. Apart from a study of vertebral fractures, we have not found any histological description of cancellous bone healing in humans. Patients and methods We studied histological biopsies from the central part of 12 distal radial fractures obtained during surgery 6–28 days after the injury, using routine hematoxylin and eosin staining. Results New bone formation was seen in 6 cases. It was always in the form of fetal-like, disorganized woven bone. It seldom had contact with old trabeculae and appeared to have formed directly in the marrow. Cartilage was scarce or absent. The samples without bone formation showed only necrosis, scar, or old cancellous bone. Interpretation The histology suggests that cells in the midst of the marrow respond to the trauma by direct formation of bone, independently of trabecular surfaces. PMID:23570338

  11. Hydroxyapatite formation from cuttlefish bones: kinetics.

    PubMed

    Ivankovic, H; Tkalcec, E; Orlic, S; Ferrer, G Gallego; Schauperl, Z

    2010-10-01

    Highly porous hydroxyapatite (Ca(10)(PO(4))(6)·(OH)(2), HA) was prepared through hydrothermal transformation of aragonitic cuttlefish bones (Sepia officinalis L. Adriatic Sea) in the temperature range from 140 to 220°C for 20 min to 48 h. The phase composition of converted hydroxyapatite was examined by quantitative X-ray diffraction (XRD) using Rietveld structure refinement and Fourier transform infrared spectroscopy (FTIR). Johnson-Mehl-Avrami (JMA) approach was used to follow the kinetics and mechanism of transformation. Diffusion controlled one dimensional growth of HA, predominantly along the a-axis, could be defined. FTIR spectroscopy determined B-type substitutions of CO(3) (2-) groups. The morphology and microstructure of converted HA was examined by scanning electron microscopy. The general architecture of cuttlefish bones was preserved after hydrothermal treatment and the cuttlefish bones retained its form with the same channel size (~80 × 300 μm). The formation of dandelion-like HA spheres with diameter from 3 to 8 μm were observed on the surface of lamellae, which further transformed into various radially oriented nanoplates and nanorods with an average diameter of about 200-300 nm and an average length of about 8-10 μm.

  12. Is Bone Tissue Really Affected by Swimming? A Systematic Review

    PubMed Central

    Gómez-Bruton, Alejandro; Gónzalez-Agüero, Alejandro; Gómez-Cabello, Alba; Casajús, José A.; Vicente-Rodríguez, Germán

    2013-01-01

    Background Swimming, a sport practiced in hypogravity, has sometimes been associated with decreased bone mass. Aim This systematic review aims to summarize and update present knowledge about the effects of swimming on bone mass, structure and metabolism in order to ascertain the effects of this sport on bone tissue. Methods A literature search was conducted up to April 2013. A total of 64 studies focusing on swimmers bone mass, structure and metabolism met the inclusion criteria and were included in the review. Results It has been generally observed that swimmers present lower bone mineral density than athletes who practise high impact sports and similar values when compared to sedentary controls. However, swimmers have a higher bone turnover than controls resulting in a different structure which in turn results in higher resistance to fracture indexes. Nevertheless, swimming may become highly beneficial regarding bone mass in later stages of life. Conclusion Swimming does not seem to negatively affect bone mass, although it may not be one of the best sports to be practised in order to increase this parameter, due to the hypogravity and lack of impact characteristic of this sport. Most of the studies included in this review showed similar bone mineral density values in swimmers and sedentary controls. However, swimmers present a higher bone turnover than sedentary controls that may result in a stronger structure and consequently in a stronger bone. PMID:23950908

  13. Roles of Chondrocytes in Endochondral Bone Formation and Fracture Repair.

    PubMed

    Hinton, R J; Jing, Y; Jing, J; Feng, J Q

    2017-01-01

    The formation of the mandibular condylar cartilage (MCC) and its subchondral bone is an important but understudied topic in dental research. The current concept regarding endochondral bone formation postulates that most hypertrophic chondrocytes undergo programmed cell death prior to bone formation. Under this paradigm, the MCC and its underlying bone are thought to result from 2 closely linked but separate processes: chondrogenesis and osteogenesis. However, recent investigations using cell lineage tracing techniques have demonstrated that many, perhaps the majority, of bone cells are derived via direct transformation from chondrocytes. In this review, the authors will briefly discuss the history of this idea and describe recent studies that clearly demonstrate that the direct transformation of chondrocytes into bone cells is common in both long bone and mandibular condyle development and during bone fracture repair. The authors will also provide new evidence of a distinct difference in ossification orientation in the condylar ramus (1 ossification center) versus long bone ossification formation (2 ossification centers). Based on our recent findings and those of other laboratories, we propose a new model that contrasts the mode of bone formation in much of the mandibular ramus (chondrocyte-derived) with intramembranous bone formation of the mandibular body (non-chondrocyte-derived).

  14. Decreased bone turnover with balanced resorption and formation prevent cortical bone loss during disuse (hibernation) in grizzly bears (Ursus arctos horribilis).

    PubMed

    McGee, Meghan E; Maki, Aaron J; Johnson, Steven E; Nelson, O Lynne; Robbins, Charles T; Donahue, Seth W

    2008-02-01

    Disuse uncouples bone formation from resorption, leading to increased porosity, decreased bone geometrical properties, and decreased bone mineral content which compromises bone mechanical properties and increases fracture risk. However, black bear bone properties are not adversely affected by aging despite annual periods of disuse (i.e., hibernation), which suggests that bears either prevent bone loss during disuse or lose bone and subsequently recover it at a faster rate than other animals. Here we show decreased cortical bone turnover during hibernation with balanced formation and resorption in grizzly bear femurs. Hibernating grizzly bear femurs were less porous and more mineralized, and did not demonstrate any changes in cortical bone geometry or whole bone mechanical properties compared to active grizzly bear femurs. The activation frequency of intracortical remodeling was 75% lower during hibernation than during periods of physical activity, but the normalized mineral apposition rate was unchanged. These data indicate that bone turnover decreases during hibernation, but osteons continue to refill at normal rates. There were no changes in regional variation of porosity, geometry, or remodeling indices in femurs from hibernating bears, indicating that hibernation did not preferentially affect one region of the cortex. Thus, grizzly bears prevent bone loss during disuse by decreasing bone turnover and maintaining balanced formation and resorption, which preserves bone structure and strength. These results support the idea that bears possess a biological mechanism to prevent disuse osteoporosis.

  15. Mechanical stimulation of bone marrow in situ induces bone formation in trabecular explants.

    PubMed

    Birmingham, E; Kreipke, T C; Dolan, E B; Coughlin, T R; Owens, P; McNamara, L M; Niebur, G L; McHugh, P E

    2015-04-01

    Low magnitude high frequency (LMHF) loading has been shown to have an anabolic effect on trabecular bone in vivo. However, the precise mechanical signal imposed on the bone marrow cells by LMHF loading, which induces a cellular response, remains unclear. This study investigates the influence of LMHF loading, applied using a custom designed bioreactor, on bone adaptation in an explanted trabecular bone model, which isolated the bone and marrow. Bone adaptation was investigated by performing micro CT scans pre and post experimental LMHF loading, using image registration techniques. Computational fluids dynamic models were generated using the pre-experiment scans to characterise the mechanical stimuli imposed by the loading regime prior to adaptation. Results here demonstrate a significant increase in bone formation in the LMHF loaded group compared to static controls and media flow groups. The calculated shear stress in the marrow was between 0.575 and 0.7 Pa, which is within the range of stimuli known to induce osteogenesis by bone marrow mesenchymal stem cells in vitro. Interestingly, a correlation was found between the bone formation balance (bone formation/resorption), trabecular number, trabecular spacing, mineral resorption rate, bone resorption rate and mean shear stresses. The results of this study suggest that the magnitude of the shear stresses generated due to LMHF loading in the explanted bone cores has a contributory role in the formation of trabecular bone and improvement in bone architecture parameters.

  16. Time course of disassociation of bone formation signals with bone mass and bone strength in sclerostin antibody treated ovariectomized rats.

    PubMed

    Ma, Yanfei L; Hamang, Matthew; Lucchesi, Jonathan; Bivi, Nicoletta; Zeng, Qianqiang; Adrian, Mary D; Raines, Sarah E; Li, Jiliang; Kuhstoss, Stuart A; Obungu, Victor; Bryant, Henry U; Krishnan, Venkatesh

    2017-04-01

    Sclerostin antibodies increase bone mass by stimulating bone formation. However, human and animal studies show that bone formation increases transiently and returns to pre-treatment level despite ongoing antibody treatment. To understand its mechanism of action, we studied the time course of bone formation, correlating the rate and extent of accrual of bone mass and strength after sclerostin antibody treatment. Ovariectomized (OVX) rats were treated with a sclerostin-antibody (Scle-ab) at 20mg/kg sc once weekly and sacrificed at baseline and 2, 3, 4, 6, and 8weeks post-treatment. In Scle-ab treated rats, serum PINP and OCN rapidly increased at week 1, peaked around week 3, and returned to OVX control levels by week 6. Transcript analyses from the distal femur revealed an early increase in bone formation followed by a sustained decrease in bone resorption genes. Lumbar vertebral (LV) osteoblast surface increased 88% by week 2, and bone formation rate (BFR/BS) increased 138% by week 4. Both parameters were below OVX control by week 8. Bone formation was primarily a result of modeling based formation. Endocortical and periosteal BFR/BS peaked around week 4 at 313% and 585% of OVX control, respectively. BFR/BS then declined but remained higher than OVX control on both surfaces through week 8. Histomorphometric analyses showed LV-BV/TV did not further increase after week 4, while BMD continued to increase at LV, mid femur (MF), and femoral neck (FN) through week 8. Biomechanical tests showed a similar improvement in bone strength through 8weeks in MF and FN, but bone strength plateaued between weeks 6 and 8 for LV. Our data suggest that bone formation with Scle-ab treatment is rapid and modeling formation dominated in OVX rats. Although transient, the bone formation response persists longer in cortical than trabecular bone.

  17. Moderate-Intensity Rotating Magnetic Fields Do Not Affect Bone Quality and Bone Remodeling in Hindlimb Suspended Rats

    PubMed Central

    Shen, Guanghao; Zhai, Mingming; Tong, Shichao; Xu, Qiaoling; Xie, Kangning; Wu, Xiaoming; Tang, Chi; Xu, Xinmin; Liu, Juan; Guo, Wei; Jiang, Maogang; Luo, Erping

    2014-01-01

    Abundant evidence has substantiated the positive effects of pulsed electromagnetic fields (PEMF) and static magnetic fields (SMF) on inhibiting osteopenia and promoting fracture healing. However, the osteogenic potential of rotating magnetic fields (RMF), another common electromagnetic application modality, remains poorly characterized thus far, although numerous commercial RMF treatment devices have been available on the market. Herein the impacts of RMF on osteoporotic bone microarchitecture, bone strength and bone metabolism were systematically investigated in hindlimb-unloaded (HU) rats. Thirty two 3-month-old male Sprague-Dawley rats were randomly assigned to the Control (n = 10), HU (n = 10) and HU with RMF exposure (HU+RMF, n = 12) groups. Rats in the HU+RMF group were subjected to daily 2-hour exposure to moderate-intensity RMF (ranging from 0.60 T to 0.38 T) at 7 Hz for 4 weeks. HU caused significant decreases in body mass and soleus muscle mass of rats, which were not obviously altered by RMF. Three-point bending test showed that the mechanical properties of femurs in HU rats, including maximum load, stiffness, energy absorption and elastic modulus were not markedly affected by RMF. µCT analysis demonstrated that 4-week RMF did not significantly prevent HU-induced deterioration of femoral trabecular and cortical bone microarchitecture. Serum biochemical analysis showed that RMF did not significantly change HU-induced decrease in serum bone formation markers and increase in bone resorption markers. Bone histomorphometric analysis further confirmed that RMF showed no impacts on bone remodeling in HU rats, as evidenced by unchanged mineral apposition rate, bone formation rate, osteoblast numbers and osteoclast numbers in cancellous bone. Together, our findings reveal that RMF do not significantly affect bone microstructure, bone mechanical strength and bone remodeling in HU-induced disuse osteoporotic rats. Our study indicates potentially

  18. Bone formation and resorption markers as diagnostic tools for bone metastases evaluation.

    PubMed

    Galliera, Emanuela; Luzzati, Alessandro; Perrucchini, Giuseppe; Gagliano, Fabio; Colloredo Mels, Ludovica; Banfi, Giuseppe; Corsi Romanelli, Massimiliano Marco; Drago, Lorenzo

    2012-12-27

    Bone metastases are a frequent complication of several types of cancers. Since bone metastases are difficult to diagnose with the current available approaches, there is a demand for new methods for assessing bone response. In this context, biochemical markers of bone remodeling may provide useful information on bone turnover that, in turn, may reflect disease activity in bone. In this study we tested a panel of bone remodeling markers (distinguishing between bone formation and bone resorption ones) in different groups of cancer patients, so as to evaluate the potential clinical role of the examined bone remodeling markers in the early diagnosis of metastases formation and progression. Among the bone resorption markers, tartrate resistant acid phosphatase 5b (TRAP5b) resulted the most specific for the metastatic tumor stage. Both the bone formation markers we analyzed displayed a direct correlation (positive for bone-specific alkaline phosphatase [BAP] and negative for osteocalcin [OC]) with tumor disease progression, ranging from healthy controls to primary tumor and, ultimately, to the metastatic stage. Taken together our results suggest that these markers can be valuable tools to be used, in parallel with traditional methods of metastases diagnosis, in order to monitor more in detail the pathological effect of metastases progression in bone tissue.

  19. Regulation of bone formation and remodeling by G-protein-coupled receptor 48.

    PubMed

    Luo, Jian; Zhou, Wei; Zhou, Xin; Li, Dali; Weng, Jinsheng; Yi, Zhengfang; Cho, Sung Gook; Li, Chenghai; Yi, Tingfang; Wu, Xiushan; Li, Xiao-Ying; de Crombrugghe, Benoit; Höök, Magnus; Liu, Mingyao

    2009-08-01

    G-protein-coupled receptor (GPCR) 48 (Gpr48; Lgr4), a newly discovered member of the glycoprotein hormone receptor subfamily of GPCRs, is an orphan GPCR of unknown function. Using a knockout mouse model, we have characterized the essential roles of Gpr48 in bone formation and remodeling. Deletion of Gpr48 in mice results in a dramatic delay in osteoblast differentiation and mineralization, but not in chondrocyte proliferation and maturation, during embryonic bone formation. Postnatal bone remodeling is also significantly affected in Gpr48(-/-) mice, including the kinetic indices of bone formation rate, bone mineral density and osteoid formation, whereas the activity and number of osteoclasts are increased as assessed by tartrate-resistant acid phosphatase staining. Examination of the molecular mechanism of Gpr48 action in bone formation revealed that Gpr48 can activate the cAMP-PKA-CREB signaling pathway to regulate the expression level of Atf4 in osteoblasts. Furthermore, we show that Gpr48 significantly downregulates the expression levels of Atf4 target genes/proteins, such as osteocalcin (Ocn; Bglap2), bone sialoprotein (Bsp; Ibsp) and collagen. Together, our data demonstrate that Gpr48 regulates bone formation and remodeling through the cAMP-PKA-Atf4 signaling pathway.

  20. The impact of skeletal unloading on bone formation

    NASA Technical Reports Server (NTRS)

    Bikle, Daniel D.; Sakata, Takeshi; Halloran, Bernard P.

    2003-01-01

    Skeletal unloading leads to decreased bone formation and decreased bone mass. Bone resorption is uncoupled from bone formation, contributing to the bone loss. During space flight bone is lost principally from the bones most loaded in the 1 g environment. Determining the mechanism(s) by which loading of bone is sensed and translated into a signal(s) controlling bone formation remains the holy grail in this field. It seems likely that matrix/cell interactions will underlie much of the mechanocoupling. Integrins are a prime mediator of such interactions. The role for systemic hormones such as PTH, GH and 1,25(OH)2D compared to locally produced factors such as IGF-I, PTHrP, BMPs and TGF beta in modulating the cellular response to load remains unclear. Our studies demonstrate that skeletal unloading leads to resistance to the anabolic actions of IGF-I on bone as a result of failure of IGF-I to activate its own signaling pathways. This is associated with a reduction in integrin expression, suggesting crosstalk between these two pathways. As the mechanism(s) by which bone responds to changes in mechanical load with changes in bone formation is further elucidated, applications of this knowledge to other etiologies of osteoporosis are likely to develop. Skeletal unloading provides a perturbation in bone mineral homeostasis that can be used to understand the mechanisms by which bone mineral homeostasis is maintained, and that such understanding will lead to effective treatment for disuse osteoporosis in addition to preventive measures for the bone loss that accompanies space travel.

  1. Lutein, a carotenoid, suppresses osteoclastic bone resorption and stimulates bone formation in cultures.

    PubMed

    Tominari, Tsukasa; Matsumoto, Chiho; Watanabe, Kenta; Hirata, Michiko; Grundler, Florian M W; Inada, Masaki; Miyaura, Chisato

    2017-02-01

    Lutein, a member of the xanthophyll family of carotenoids, suppressed IL-1-induced osteoclast differentiation and bone resorption. The survival of mature osteoclasts was also suppressed by lutein in cultures. When lutein was added to the cultures of osteoblasts, lutein enhanced the formation of mineralized bone nodules by elevating BMP2 expression and inhibiting sclerostin expression. Lutein may be beneficial for bone health.

  2. The effect of diabetes mellitus on rat mandibular bone formation and microarchitecture.

    PubMed

    Abbassy, Mona A; Watari, Ippei; Soma, Kunimichi

    2010-08-01

    The aim of this study was to assess the effect of type 1 diabetes mellitus (DM) on the structure of mandibular bone and on the changes of alveolar/jaw bone formation. Experimental DM was induced in 3-wk-old male Wistar rats by a single dose of 60 mg/kg body weight of streptozotocin. All rats were injected with calcein on days 21 and 28. The rats were killed when 8 wk of age. Bone structure was analyzed by bone histomorphometry, microcomputed tomography (micro-CT), and histological section. Histomorphometric analysis showed that the mineral apposition and the bone formation rates in most of the mandibular regions were significantly decreased in the DM group compared with the control group. Micro-CT analysis showed significant deterioration of the bone quality in rats with DM. For a histometric measure of bone resorption, the number of osteoclasts along the distal surface of the alveolar wall was counted. The number of osteoclasts was significantly lower in the rats with DM than in the controls. These findings suggest that uncontrolled DM decreases mandibular bone formation, reduces the rate of bone turnover in the alveolar wall surrounding the root, and affects the quality of bone structure resulting in retardation of its skeletal development.

  3. Inhibition of cortical and trabecular bone formation in the long bones of immobilized monkeys

    NASA Technical Reports Server (NTRS)

    Wronski, T. J.; Morey, E. R.

    1983-01-01

    Tetracycline derivatives are administered on three separate occasions to label the sites of bone formation. Determinations are made of the tetracycline-labeling frequency and mineral apposition rate of osteons and trabecular bone surfaces in the humerus and femur. The inhibition of bone formation induced by immobilization is found to be more pronounced in trabecular bone. The immobilized monkeys exhibit a moderate, but statistically nonsignificant, reduction in the percentage of osteons forming bone. Conversely, the dramatic decline in the percentage of trabecular surfaces undergoing bone formation in the monkeys is found to be highly significant. The diminished rate of mineral apposition in osteons is seen as suggesting that osteoblastic activity is impaired in cortical bone during immobilization.

  4. Communication between nitric oxide synthase and positively-charged surface and bone formation promotion.

    PubMed

    Zhang, Wei; Liu, Jun; Shi, Haigang; Yang, Kun; Wang, Pingli; Wang, Gexia; Liu, Na; Wang, Huaiyu; Ji, Junhui; Chu, Paul K

    2016-12-01

    Despite the effects on physiology of bone marrow mesenchymal stem cells (BMSCs) and bone tissue, biological signal communication between bone implants and them is seldom employed as a guidance to create an osteo-inductive interface. Herein, the positively-charged surface is constructed on bone implant from the perspective of mediation of nitric oxide synthase (NOS) expression to signal BMSCs osteo-differentiation. In vitro and in vivo results indicate that the proper surface potential on the positively-charged surface affects NOS to express a high level of inducible nitric oxide synthase (iNOS) in three NOS isoforms of the contacted BMSCs, upregulates their osteogenetic expression, and ultimately foster new bone growth. However, an excessively high surface potential produces substantial immunomodulatory effects thereby offsetting the aforementioned advantages. This study demonstrates that fine-tuning of the positively-charged surface and proper utilization of the communication between NOS and bone implants promote bone formation.

  5. Brief review of models of ectopic bone formation.

    PubMed

    Scott, Michelle A; Levi, Benjamin; Askarinam, Asal; Nguyen, Alan; Rackohn, Todd; Ting, Kang; Soo, Chia; James, Aaron W

    2012-03-20

    Ectopic bone formation is a unique biologic entity--distinct from other areas of skeletal biology. Animal research models of ectopic bone formation most often employ rodent models and have unique advantages over orthotopic (bone) environments, including a relative lack of bone cytokine stimulation and cell-to-cell interaction with endogenous (host) bone-forming cells. This allows for relatively controlled in vivo experimental bone formation. A wide variety of ectopic locations have been used for experimentation, including subcutaneous, intramuscular, and kidney capsule transplantation. The method, benefits and detractions of each method are summarized in the following review. Briefly, subcutaneous implantation is the simplest method. However, the most pertinent concern is the relative paucity of bone formation in comparison to other models. Intramuscular implantation is also widely used and relatively simple, however intramuscular implants are exposed to skeletal muscle satellite progenitor cells. Thus, distinguishing host from donor osteogenesis becomes challenging without cell-tracking studies. The kidney capsule (perirenal or renal capsule) method is less widely used and more technically challenging. It allows for supraphysiologic blood and nutrient resource, promoting robust bone growth. In summary, ectopic bone models are extremely useful in the evaluation of bone-forming stem cells, new osteoinductive biomaterials, and growth factors; an appropriate choice of model, however, will greatly increase experimental success.

  6. Beyond the functional matrix hypothesis: a network null model of human skull growth for the formation of bone articulations

    PubMed Central

    Esteve-Altava, Borja; Rasskin-Gutman, Diego

    2014-01-01

    Craniofacial sutures and synchondroses form the boundaries among bones in the human skull, providing functional, developmental and evolutionary information. Bone articulations in the skull arise due to interactions between genetic regulatory mechanisms and epigenetic factors such as functional matrices (soft tissues and cranial cavities), which mediate bone growth. These matrices are largely acknowledged for their influence on shaping the bones of the skull; however, it is not fully understood to what extent functional matrices mediate the formation of bone articulations. Aiming to identify whether or not functional matrices are key developmental factors guiding the formation of bone articulations, we have built a network null model of the skull that simulates unconstrained bone growth. This null model predicts bone articulations that arise due to a process of bone growth that is uniform in rate, direction and timing. By comparing predicted articulations with the actual bone articulations of the human skull, we have identified which boundaries specifically need the presence of functional matrices for their formation. We show that functional matrices are necessary to connect facial bones, whereas an unconstrained bone growth is sufficient to connect non-facial bones. This finding challenges the role of the brain in the formation of boundaries between bones in the braincase without neglecting its effect on skull shape. Ultimately, our null model suggests where to look for modified developmental mechanisms promoting changes in bone growth patterns that could affect the development and evolution of the head skeleton. PMID:24975579

  7. Beyond the functional matrix hypothesis: a network null model of human skull growth for the formation of bone articulations.

    PubMed

    Esteve-Altava, Borja; Rasskin-Gutman, Diego

    2014-09-01

    Craniofacial sutures and synchondroses form the boundaries among bones in the human skull, providing functional, developmental and evolutionary information. Bone articulations in the skull arise due to interactions between genetic regulatory mechanisms and epigenetic factors such as functional matrices (soft tissues and cranial cavities), which mediate bone growth. These matrices are largely acknowledged for their influence on shaping the bones of the skull; however, it is not fully understood to what extent functional matrices mediate the formation of bone articulations. Aiming to identify whether or not functional matrices are key developmental factors guiding the formation of bone articulations, we have built a network null model of the skull that simulates unconstrained bone growth. This null model predicts bone articulations that arise due to a process of bone growth that is uniform in rate, direction and timing. By comparing predicted articulations with the actual bone articulations of the human skull, we have identified which boundaries specifically need the presence of functional matrices for their formation. We show that functional matrices are necessary to connect facial bones, whereas an unconstrained bone growth is sufficient to connect non-facial bones. This finding challenges the role of the brain in the formation of boundaries between bones in the braincase without neglecting its effect on skull shape. Ultimately, our null model suggests where to look for modified developmental mechanisms promoting changes in bone growth patterns that could affect the development and evolution of the head skeleton.

  8. Alteration of proteoglycan sulfation affects bone growth and remodeling.

    PubMed

    Gualeni, Benedetta; de Vernejoul, Marie-Christine; Marty-Morieux, Caroline; De Leonardis, Fabio; Franchi, Marco; Monti, Luca; Forlino, Antonella; Houillier, Pascal; Rossi, Antonio; Geoffroy, Valerie

    2013-05-01

    Diastrophic dysplasia (DTD) is a chondrodysplasia caused by mutations in the SLC26A2 gene, leading to reduced intracellular sulfate pool in chondrocytes, osteoblasts and fibroblasts. Hence, proteoglycans are undersulfated in the cartilage and bone of DTD patients. To characterize the bone phenotype of this skeletal dysplasia we used the Slc26a2 knock-in mouse (dtd mouse), that was previously validated as an animal model of DTD in humans. X-rays, bone densitometry, static and dynamic histomorphometry, and in vitro studies revealed a primary bone defect in the dtd mouse model. We showed in vivo that this primary bone defect in dtd mice is due to decreased bone accrual associated with a decreased trabecular and periosteal appositional rate at the cell level in one month-old mice. Although the osteoclast number evaluated by histomorphometry was not different in dtd compared to wild-type mice, urine analysis of deoxypyridinoline cross-links and serum levels of type I collagen C-terminal telopeptides showed a higher resorption rate in dtd mice compared to wild-type littermates. Electron microscopy studies showed that collagen fibrils in bone were thinner and less organized in dtd compared to wild-type mice. These data suggest that the low bone mass observed in mutant mice could possibly be linked to the different bone matrix compositions/organizations in dtd mice triggering changes in osteoblast and osteoclast activities. Overall, these results suggest that proteoglycan undersulfation not only affects the properties of hyaline cartilage, but can also lead to unbalanced bone modeling and remodeling activities, demonstrating the importance of proteoglycan sulfation in bone homeostasis.

  9. Alteration of proteoglycan sulfation affects bone growth and remodeling

    PubMed Central

    Gualeni, Benedetta; de Vernejoul, Marie-Christine; Marty-Morieux, Caroline; De Leonardis, Fabio; Franchi, Marco; Monti, Luca; Forlino, Antonella; Houillier, Pascal; Rossi, Antonio; Geoffroy, Valerie

    2013-01-01

    Diastrophic dysplasia (DTD) is a chondrodysplasia caused by mutations in the SLC26A2 gene, leading to reduced intracellular sulfate pool in chondrocytes, osteoblasts and fibroblasts. Hence, proteoglycans are undersulfated in the cartilage and bone of DTD patients. To characterize the bone phenotype of this skeletal dysplasia we used the Slc26a2 knock-in mouse (dtd mouse), that was previously validated as an animal model of DTD in humans. X-rays, bone densitometry, static and dynamic histomorphometry, and in vitro studies revealed a primary bone defect in the dtd mouse model. We showed in vivo that this primary bone defect in dtd mice is due to decreased bone accrual associated with a decreased trabecular and periosteal appositional rate at the cell level in one month-old mice. Although the osteoclast number evaluated by histomorphometry was not different in dtd compared to wild-type mice, urine analysis of deoxypyridinoline cross-links and serum levels of type I collagen C-terminal telopeptides showed a higher resorption rate in dtd mice compared to wild-type littermates. Electron microscopy studies showed that collagen fibrils in bone were thinner and less organized in dtd compared to wild-type mice. These data suggest that the low bone mass observed in mutant mice could possibly be linked to the different bone matrix compositions/organizations in dtd mice triggering changes in osteoblast and osteoclast activities. Overall, these results suggest that proteoglycan undersulfation not only affects the properties of hyaline cartilage, but can also lead to unbalanced bone modeling and remodeling activities, demonstrating the importance of proteoglycan sulfation in bone homeostasis. PMID:23369989

  10. Lanthanum carbonate stimulates bone formation in a rat model of renal insufficiency with low bone turnover.

    PubMed

    Fumoto, Toshio; Ito, Masako; Ikeda, Kyoji

    2014-09-01

    Control of phosphate is important in the management of chronic kidney disease with mineral and bone disorder (CKD-MBD), for which lanthanum carbonate, a non-calcium phosphate-binding agent, has recently been introduced; however, it remains to be determined whether it has any beneficial or deleterious effect on bone remodeling. In the present study, the effects of lanthanum carbonate were examined in an animal model that mimics low turnover bone disease in CKD, i.e., thyroparathyroidectomized (TPTX) and 5/6 nephrectomized (NX) rats undergoing a constant infusion of parathyroid hormone (PTH) and thyroxine injections (TPTX-PTH-5/6NX). Bone histomorphometry at the second lumbar vertebra and tibial metaphysis revealed that both bone formation and resorption were markedly suppressed in the TPTX-PTH-5/6NX model compared with the sham-operated control group, and treatment with lanthanum carbonate was associated with the stimulation of bone formation but not an acceleration of bone resorption. Lanthanum treatment caused a robust stimulation of bone formation with an activation of osteoblasts on the endosteal surface of femoral diaphysis, leading to an increase in cortical bone volume. Thus, lanthanum carbonate has the potential to stimulate bone formation in cases of CKD-MBD with suppressed bone turnover.

  11. Tooth dentin defects reflect genetic disorders affecting bone mineralization

    PubMed Central

    Vital, S. Opsahl; Gaucher, C.; Bardet, C.; Rowe, P.S.; George, A.; Linglart, A.; Chaussain, C.

    2012-01-01

    Several genetic disorders affecting bone mineralization may manifest during dentin mineralization. Dentin and bone are similar in several aspects, especially pertaining to the composition of the extracellular matrix (ECM) which is secreted by well-differentiated odontoblasts and osteoblasts, respectively. However, unlike bone, dentin is not remodelled and is not involved in the regulation of calcium and phosphate metabolism. In contrast to bone, teeth are accessible tissues with the shedding of deciduous teeth and the extractions of premolars and third molars for orthodontic treatment. The feasibility of obtaining dentin makes this a good model to study biomineralization in physiological and pathological conditions. In this review, we focus on two genetic diseases that disrupt both bone and dentin mineralization. Hypophosphatemic rickets is related to abnormal secretory proteins involved in the ECM organization of both bone and dentin, as well as in the calcium and phosphate metabolism. Osteogenesis imperfecta affects proteins involved in the local organization of the ECM. In addition, dentin examination permits evaluation of the effects of the systemic treatment prescribed to hypophosphatemic patients during growth. In conclusion, dentin constitutes a valuable tool for better understanding of the pathological processes affecting biomineralization. PMID:22296718

  12. New bone formation by orthodontic tooth movement for implant placement

    PubMed Central

    Cabbar, Fatih; Nur, Rahime Burcu; Dikici, Burcu; Canpolat, Ceyhun; Capar, Gonca Duygu

    2016-01-01

    Bone defects at the anterior regions of the jaws often cause esthetic problems such as gingival disharmonies and longer crowns than neighboring teeth. Variety of procedures can be used in this region for achieving sufficient bone volume with or without different bone graft materials. All of these procedures has their own advantages and disadventages. New bone formation was defined with orthodontic tooth movement in different regions. In this case we present the use of orthodontic tooth movement, for achieving sufficient bone volume, in anterior maxillary region, for esthetic and functional results. PMID:28299281

  13. 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.

  14. In Vitro Bone Cell Models: Impact of Fluid Shear Stress on Bone Formation

    PubMed Central

    Wittkowske, Claudia; Reilly, Gwendolen C.; Lacroix, Damien; Perrault, Cecile M.

    2016-01-01

    This review describes the role of bone cells and their surrounding matrix in maintaining bone strength through the process of bone remodeling. Subsequently, this work focusses on how bone formation is guided by mechanical forces and fluid shear stress in particular. It has been demonstrated that mechanical stimulation is an important regulator of bone metabolism. Shear stress generated by interstitial fluid flow in the lacunar-canalicular network influences maintenance and healing of bone tissue. Fluid flow is primarily caused by compressive loading of bone as a result of physical activity. Changes in loading, e.g., due to extended periods of bed rest or microgravity in space are associated with altered bone remodeling and formation in vivo. In vitro, it has been reported that bone cells respond to fluid shear stress by releasing osteogenic signaling factors, such as nitric oxide, and prostaglandins. This work focusses on the application of in vitro models to study the effects of fluid flow on bone cell signaling, collagen deposition, and matrix mineralization. Particular attention is given to in vitro set-ups, which allow long-term cell culture and the application of low fluid shear stress. In addition, this review explores what mechanisms influence the orientation of collagen fibers, which determine the anisotropic properties of bone. A better understanding of these mechanisms could facilitate the design of improved tissue-engineered bone implants or more effective bone disease models. PMID:27896266

  15. Heterotopic new bone formation causes resorption of the inductive bone matrix

    SciTech Connect

    Nilsson, O.S.; Persson, P.E.; Ekelund, A. )

    1990-08-01

    The bone matrix of growing rats was labeled by multiple injections of 3H-proline, and demineralized bone matrix (DBM) was prepared. The DBM was allotransplanted heterotopically into growing rats. New bone formation was induced in and around the implants. The new bone formation was accompanied by a decrease in the content of 3H; 20 and 30 days after implantation, 72% and 46%, respectively, of the activity remained in the implants. Daily injections of indomethacin (2 mg/kg) inhibited calcium uptake by about 20% at 20 and 30 days and inhibited the release of 3H from the DBM to a similar degree. Heterotopic bone induction by DBM is accompanied by matrix resorption, and inhibition of the new bone formation decreases the resorption of DBM.

  16. VEGF expression in mesenchymal stem cells promotes bone formation of tissue-engineered bones.

    PubMed

    Liu, Boling; Li, Xihai; Liang, Guiqing; Liu, Xianxiang

    2011-01-01

    The purpose of this study was to investigate the in vivo vascularization and bone formation activity of tissue-engineered bone constructed using bone marrow mesenchymal stem cells (MSCs) transfected with vascular endothelial growth factor (VEGF). The expression of VEGF165 in rat bone marrow MSCs was confirmed using RT-PCR and immunohistochemistry. The MSCs were cultured together with nano-hydroxyapatite/collagen (NHAC) to form tissue-engineered bone. Untransfected MSCs were used as controls. The mice were sacrificed, and the bone xenografts were analyzed using immunohistochemistry and quantified for the degree of vascularization and new bone formation. Based on our results, expression of the VEGF165 gene was detected using RT-PCR and immunohistochemistry following transfection and 4 weeks of selection. The co-cultured NHAC- and VEGF-transfected MSCs had significantly higher alkaline phosphatase (AP) activity compared to the controls (P<0.05). In the mice that received the tissue-engineered bone xenografts, clumps of cartilage cells, irregular bone-like tissue and microvessels were observed. The growth of these structures progressed with time. In the control mice, however, only small amounts of bone-like and fibrotic tissue were observed. The differences between the control and experimental groups were statistically significant (P<0.05). In conclusion, VEGF165‑transfected bone marrow MSCs promotes vascularization of tissue-engineered bone and ectopic osteogenesis.

  17. Mushroom Extracts Decrease Bone Resorption and Improve Bone Formation.

    PubMed

    Erjavec, Igor; Brkljacic, Jelena; Vukicevic, Slobodan; Jakopovic, Boris; Jakopovich, Ivan

    2016-01-01

    Mushroom extracts have shown promising effects in the treatment of cancer and various chronic diseases. Osteoporosis is considered one of the most widespread chronic diseases, for which currently available therapies show mixed results. In this research we investigated the in vitro effects of water extracts of the culinary-medicinal mushrooms Trametes versicolor, Grifola frondosa, Lentinus edodes, and Pleurotus ostreatus on a MC3T3-E1 mouse osteoblast-like cell line, primary rat osteoblasts, and primary rat osteoclasts. In an animal osteoporosis model, rats were ovariectomized and then fed 2 mushroom blends of G. frondosa and L. edodes for 42 days. Bone loss was monitored using densitometry (dual-energy X-ray absorptiometry) and micro computed tomography. In the concentration test, mushroom extracts showed no toxic effect on MC3T3-E1 cells; a dose of 24 µg/mL showed the most proliferative effect. Mushroom extracts of T. versicolor, G. frondosa, and L. edodes inhibited osteoclast activity, whereas the extract of L. edodes increased osteoblast mineralization and the production of osteocalcin, a specific osteoblastic marker. In animals, mushroom extracts did not prevent trabecular bone loss in the long bones. However, we show for the first time that the treatment with a combination of extracts from L. edodes and G. frondosa significantly reduced trabecular bone loss at the lumbar spine. Inhibitory properties of extracts from L. edodes on osteoclasts and the promotion of osteoblasts in vitro, together with the potential to decrease lumbar spine bone loss in an animal osteoporosis model, indicate that medicinal mushroom extracts can be considered as a preventive treatment and/or a supplement to pharmacotherapy to enhance its effectiveness and ameliorate its harmful side effects.

  18. FLUORIDE EFFECTS ON BONE FORMATION AND MINERALIZATION ARE INFLUENCED BY GENETICS

    PubMed Central

    Mousny, M.; Omelon, S.; Wise, L.; Everett, E. T.; Dumitriu, M.; Holmyard, D. P.; Banse, X.; Devogelaer, J. P.; Grynpas, M. D

    2008-01-01

    effect on bone microarchitecture in these three strains. The increased osteoid formation and decreased mineralization heterogeneity support the theory that F− delays mineralization of new bone. The increasing crystal width with increasing F− dose confirms earlier results and correlates with most of the decreased mechanical properties. An increase in bone F− may affect the mineral-organic interfacial bonding and/or bone matrix proteins, interfering with bone crystal growth inhibition on the crystallite faces as well as bonding between the mineral and organic interface. The smaller bone crystallites of the 129P3/J (resistant) strain may indicate a stronger organic/inorganic interface, reducing crystallite growth rate and increasing interfacial mechanical strength. PMID:18755305

  19. Effect of fluoride-substituted apatite on in vivo bone formation.

    PubMed

    Inoue, Miho; Rodriguez, Andrea P; Nagai, Noriyuki; Nagatsuka, Hitoshi; LeGeros, Racquel Z; Tsujigiwa, Hidetsugu; Inoue, Masahisa; Kishimoto, Etsuo; Takagi, Shin

    2011-05-01

    Biological apatites are characterized by the presence of minor constituents such as magnesium (Mg), chloride (Cl), or fluoride (F) ions. These ions affect cell proliferation and osteoblastic differentiation during bone tissue formation. F-substituted apatites are being explored as potential bonegraft materials. The aim of the present study is to investigate the mechanism of bone formation induced by fluoride-substituted apatite (FAp) by analyzing the effect of FAp on the process of in vivo bone formation. FAps containing different F concentrations (l-FAp: 0.48 wt%, m-FAp: 0.91 wt%, h-FAp: 2.23 wt%) and calcium-deficient apatite (CDA), as positive control, were implanted in rat tibia and bone formation was evaluated by histological examination, immuhistochemistry, in situ hybridization and tartrate-resistant acid phosphatase examinations. The results showed that l-FAp, m-FAp, h-FAp, and CDA biomaterials allowed migration of macrophages, attachment, proliferation, and phenotypic expression of bone cells leading to new bone formation in direct apposition to the particles. However, the l-FAp preparation allowed faster bone conduction compared to the other experimental materials. These results suggest that FAp with low F concentration may be an efficient bonegraft material for dental and medical application.

  20. Up-regulation of glycolytic metabolism is required for HIF1α-driven bone formation.

    PubMed

    Regan, Jenna N; Lim, Joohyun; Shi, Yu; Joeng, Kyu Sang; Arbeit, Jeffrey M; Shohet, Ralph V; Long, Fanxin

    2014-06-10

    The bone marrow environment is among the most hypoxic in the body, but how hypoxia affects bone formation is not known. Because low oxygen tension stabilizes hypoxia-inducible factor alpha (HIFα) proteins, we have investigated the effect of expressing a stabilized form of HIF1α in osteoblast precursors. Brief stabilization of HIF1α in SP7-positive cells in postnatal mice dramatically stimulated cancellous bone formation via marked expansion of the osteoblast population. Remarkably, concomitant deletion of vascular endothelial growth factor A (VEGFA) in the mouse did not diminish bone accrual caused by HIF1α stabilization. Thus, HIF1α-driven bone formation is independent of VEGFA up-regulation and increased angiogenesis. On the other hand, HIF1α stabilization stimulated glycolysis in bone through up-regulation of key glycolytic enzymes including pyruvate dehydrogenase kinase 1 (PDK1). Pharmacological inhibition of PDK1 completely reversed HIF1α-driven bone formation in vivo. Thus, HIF1α stimulates osteoblast formation through direct activation of glycolysis, and alterations in cellular metabolism may be a broadly applicable mechanism for regulating cell differentiation.

  1. Sclerostin antibody treatment increases bone formation, bone mass, and bone strength in a rat model of postmenopausal osteoporosis.

    PubMed

    Li, Xiaodong; Ominsky, Michael S; Warmington, Kelly S; Morony, Sean; Gong, Jianhua; Cao, Jin; Gao, Yongming; Shalhoub, Victoria; Tipton, Barbara; Haldankar, Raj; Chen, Qing; Winters, Aaron; Boone, Tom; Geng, Zhaopo; Niu, Qing-Tian; Ke, Hua Zhu; Kostenuik, Paul J; Simonet, W Scott; Lacey, David L; Paszty, Chris

    2009-04-01

    The development of bone-rebuilding anabolic agents for potential use in the treatment of bone loss conditions, such as osteoporosis, has been a long-standing goal. Genetic studies in humans and mice have shown that the secreted protein sclerostin is a key negative regulator of bone formation, although the magnitude and extent of sclerostin's role in the control of bone formation in the aging skeleton is still unclear. To study this unexplored area of sclerostin biology and to assess the pharmacologic effects of sclerostin inhibition, we used a cell culture model of bone formation to identify a sclerostin neutralizing monoclonal antibody (Scl-AbII) for testing in an aged ovariectomized rat model of postmenopausal osteoporosis. Six-month-old female rats were ovariectomized and left untreated for 1 yr to allow for significant estrogen deficiency-induced bone loss, at which point Scl-AbII was administered for 5 wk. Scl-AbII treatment in these animals had robust anabolic effects, with marked increases in bone formation on trabecular, periosteal, endocortical, and intracortical surfaces. This not only resulted in complete reversal, at several skeletal sites, of the 1 yr of estrogen deficiency-induced bone loss, but also further increased bone mass and bone strength to levels greater than those found in non-ovariectomized control rats. Taken together, these preclinical results establish sclerostin's role as a pivotal negative regulator of bone formation in the aging skeleton and, furthermore, suggest that antibody-mediated inhibition of sclerostin represents a promising new therapeutic approach for the anabolic treatment of bone-related disorders, such as postmenopausal osteoporosis.

  2. Cell and Signal Components of the Microenvironment of Bone Metastasis Are Affected by Hypoxia

    PubMed Central

    Bendinelli, Paola; Maroni, Paola; Matteucci, Emanuela; Desiderio, Maria Alfonsina

    2016-01-01

    Bone metastatic cells release bone microenvironment proteins, such as the matricellular protein SPARC (secreted protein acidic and rich in cysteine), and share a cell signaling typical of the bone metabolism controlled by Runx2. The megakaryocytes in the bone marrow engrafted by the metastases seem to be one of the principal microenvironment sources of the biological stimuli, implicated in the formation of an osteoblastic niche, and affecting metastasis phenotype and colonization. Educated platelets in the circulation might derive from megakaryocytes in bone metastasis. The evaluation of predictive markers in the circulating platelets might be useful for the stratification of patients for therapeutic purposes. The hypoxic environment in bone metastasis is one of the key regulators of the network of the biological soluble and structural components of the matrix. In bone metastatic cells under hypoxia, similar patterns of Runx2 and SPARC are observed, both showing downregulation. Conversely, hypoxia induces Endothelin 1, which upregulates SPARC, and these biological stimuli may be considered prognostic markers of bone metastasis in breast carcinoma patients. PMID:27187355

  3. Mechanical loading, damping, and load-driven bone formation in mouse tibiae.

    PubMed

    Dodge, Todd; Wanis, Mina; Ayoub, Ramez; Zhao, Liming; Watts, Nelson B; Bhattacharya, Amit; Akkus, Ozan; Robling, Alexander; Yokota, Hiroki

    2012-10-01

    Mechanical loads play a pivotal role in the growth and maintenance of bone and joints. Although loading can activate anabolic genes and induce bone remodeling, damping is essential for preventing traumatic bone injury and fracture. In this study we investigated the damping capacity of bone, joint tissue, muscle, and skin using a mouse hindlimb model of enhanced loading in conjunction with finite element modeling to model bone curvature. Our hypothesis was that loads were primarily absorbed by the joints and muscle tissue, but that bone also contributed to damping through its compression and natural bending. To test this hypothesis, fresh mouse distal lower limb segments were cyclically loaded in axial compression in sequential bouts, with each subsequent bout having less surrounding tissue. A finite element model was generated to model effects of bone curvature in silico. Two damping-related parameters (phase shift angle and energy loss) were determined from the output of the loading experiments. Interestingly, the experimental results revealed that the knee joint contributed to the largest portion of the damping capacity of the limb, and bone itself accounted for approximately 38% of the total phase shift angle. Computational results showed that normal bone curvature enhanced the damping capacity of the bone by approximately 40%, and the damping effect grew at an accelerated pace as curvature was increased. Although structural curvature reduces critical loads for buckling in beam theory, evolution apparently favors maintaining curvature in the tibia. Histomorphometric analysis of the tibia revealed that in response to axial loading, bone formation was significantly enhanced in the regions that were predicted to receive a curvature-induced bending moment. These results suggest that in addition to bone's compressive damping capacity, surrounding tissues, as well as naturally-occurring bone curvature, also contribute to mechanical damping, which may ultimately affect

  4. Endochondral bone formation in embryonic mouse pre-metatarsals

    NASA Technical Reports Server (NTRS)

    Klement, B. J.; Spooner, B. S.

    1992-01-01

    Long term exposure to a reduced gravitational environment has a deleterious effect on bone. The developmental events which occur prior to initial bone deposition will provide insight into the regulation of mature bone physiology. We have characterized a system in which the events preceding bone formation take place in an isolated in vitro organ culture environment. We show that cultured pre-metatarsal tissue parallels development of pre-metatarsal tissue in the embryo. Both undergo mesenchyme differentiation and morphogenesis to form a cartilage rod, which resembles the future bone, followed by terminal chondrocyte differentiation in a definite morphogenetic pattern. These sequential steps occur prior to osteoblast maturation and bone matrix deposition in the developing organism. Alkaline phosphatase (ALP) activity is a distinctive enzymatic marker for mineralizing tissues. We have measured this activity throughout pre-metatarsal development and show (a) where in the tissue it is predominantly found, and (b) that this is indeed the mineralizing isoform of the enzyme.

  5. ANA deficiency enhances bone morphogenetic protein-induced ectopic bone formation via transcriptional events.

    PubMed

    Miyai, Kentaro; Yoneda, Mitsuhiro; Hasegawa, Urara; Toita, Sayaka; Izu, Yayoi; Hemmi, Hiroaki; Hayata, Tadayoshi; Ezura, Yoichi; Mizutani, Shuki; Miyazono, Kohei; Akiyoshi, Kazunari; Yamamoto, Tadashi; Noda, Masaki

    2009-04-17

    Ectopic bone formation after joint replacement or brain injury in humans is a serious complication that causes immobility of joints and severe pain. However, mechanisms underlying such ectopic bone formation are not fully understood. Bone morphogenetic protein (BMPs) are defined as inducers of ectopic bone formation, and they are regulated by several types of inhibitors. ANA is an antiproliferative molecule that belongs to Tob/BTG family, but its activity in bone metabolism has not been known. Here, we examined the role of ANA on ectopic bone formation activity of BMP. In ANA-deficient and wild-type mice, BMP2 was implanted to induce ectopic bone formation in muscle. ANA deficiency increased mass of newly formed bone in vivo compared with wild-type based on 3D-muCT analyses. ANA mRNA was expressed in bone in vivo as well as in osteoblastic cells in vitro. Such ANA mRNA levels were increased by BMP2 treatment in MC3T3-E1 osteoblastic cells. Overexpression of ANA suppressed BMP-induced expression of luciferase reporter gene linked to BMP response elements in these cells. Conversely, ANA mRNA knockdown by small interference RNA enhanced the BMP-dependent BMP response element reporter expression. It also enhanced BMP-induced osteoblastic differentiation in muscle-derived C2C12 cells. Immunoprecipitation assay indicated that ANA interacts with Smad8. Thus, ANA is a suppressor of ectopic bone formation induced by BMP, and this inhibitory ANA activity is a part of the negative feedback regulation of BMP function.

  6. Does gallbladder angle affect gallstone formation?

    PubMed Central

    Sanal, Bekir; Korkmaz, Mehmet; Zeren, Sezgin; Can, Fatma; Elmali, Ferhan; Bayhan, Zulfu

    2016-01-01

    Introduction Morphology of gallbladder varies considerably from person to person. We believe that one of the morphological variations of gallbladder is the “gallbladder angle”. Gallbladder varies also in “angle”, which, to the best of our knowledge, has never been investigated before. The purpose of this study was to investigate the impact of gallbladder angle on gallstone formation. Methods in this study, 1075 abdominal computed tomography (CT) images were retrospectively examined. Patients with completely normal gallbladders were selected. Among these patients, those with both abdominal ultrasound and blood tests were identified in the hospital records and included in the study. Based on the findings of the ultrasound scans, patients were divided into two groups as patients with gallstones and patients without gallstones. Following the measurement of gallbladder angles on the CT images, the groups were statistically evaluated. Results The gallbladder angle was smaller in patients with gallstones (49 ± 21 degrees and 53 ± 19 degrees) and the gallbladder with larger angle was 1.015 (1/0.985) times lower the risk of gallstone formation. However, these were not statistically significant (p>0,05). Conclusion A more vertically positioned gallbladder does not affect gallstone formation. However, a smaller gallbladder angle may facilitate gallstone formation in patients with the risk factors. Gallstones perhaps more easily and earlier develop in gallbladders with a smaller angle. PMID:27795762

  7. Osteoprogenitor cells from bone marrow and cortical bone: understanding how the environment affects their fate.

    PubMed

    Corradetti, Bruna; Taraballi, Francesca; Powell, Sebastian; Sung, David; Minardi, Silvia; Ferrari, Mauro; Weiner, Bradley K; Tasciotti, Ennio

    2015-05-01

    Bone is a dynamic organ where skeletal progenitors and hematopoietic cells share and compete for space. Presumptive mesenchymal stem cells (MSC) have been identified and harvested from the bone marrow (BM-MSC) and cortical bone fragments (CBF-MSC). In this study, we demonstrate that despite the cells sharing a common ancestor, the differences in the structural properties of the resident tissues affect cell behavior and prime them to react differently to stimuli. Similarly to the bone marrow, the cortical portion of the bone contains a unique subset of cells that stains positively for the common MSC-associated markers. These cells display different multipotent differentiation capability, clonogenic expansion, and immunosuppressive potential. In particular, when compared with BM-MSC, CBF-MSC are bigger in size, show a lower proliferation rate at early passages, have a greater commitment toward the osteogenic lineage, constitutively produce nitric oxide as a mediator for bone remodeling, and more readily respond to proinflammatory cytokines. Our data suggest that the effect of the tissue's microenvironment makes the CBF-MSC a superior candidate in the development of new strategies for bone repair.

  8. Adaptive bone formation in acellular vertebrae of sea bass (Dicentrarchus labrax L.).

    PubMed

    Kranenbarg, Sander; van Cleynenbreugel, Tim; Schipper, Henk; van Leeuwen, Johan

    2005-09-01

    Mammalian bone is an active tissue in which osteoblasts and osteoclasts balance bone mass. This process of adaptive modelling and remodelling is probably regulated by strain-sensing osteocytes. Bone of advanced teleosts is acellular yet, despite the lack of osteocytes, it is capable of an adaptive response to physical stimuli. Strenuous exercise is known to induce lordosis. Lordosis is a ventrad curvature of the vertebral column, and the affected vertebrae show an increase in bone formation. The effects of lordosis on the strain distribution in sea bass (Dicentrarchus labrax L.) vertebrae are assessed using finite element modelling. The response of the local tissue is analyzed spatially and ontogenetically in terms of bone volume. Lordotic vertebrae show a significantly increased strain energy due to the increased load compared with normal vertebrae when loaded in compression. High strain regions are found in the vertebral centrum and parasagittal ridges. The increase in strain energy is attenuated by a change in architecture due to the increased bone formation. The increased bone formation is seen mainly at the articular surfaces of the vertebrae, although some extra bone is formed in the vertebral centrum. Regions in which the highest strains are found do not spatially correlate with regions in which the most extensive bone apposition occurs in lordotic vertebrae of sea bass. Mammalian-like strain-regulated bone modelling is probably not the guiding mechanism in adaptive bone modelling of acellular sea bass vertebrae. Chondroidal ossification is found at the articular surfaces where it mediates a rapid adaptive response, potentially attenuating high stresses on the dorsal zygapophyses.

  9. Clay-Enriched Silk Biomaterials for Bone Formation

    PubMed Central

    Mieszawska, Aneta J.; Llamas, Jabier Gallego; Vaiana, Christopher A.; Kadakia, Madhavi P.; Naik, Rajesh R.; Kaplan, David L.

    2011-01-01

    The formation of silk protein/clay composite biomaterials for bone tissue formation is described. Silk fibroin serves as an organic scaffolding material offering mechanical stability suitable for bone specific uses. Clay montmorillonite (Cloisite ® Na+) and sodium silicate are sources of osteoinductive silica-rich inorganic species, analogous to bioactive bioglass-like bone repair biomaterial systems. Different clay particle-silk composite biomaterial films were compared to silk films doped with sodium silicate as controls for support of human bone marrow derived mesenchymal stem cells (hMSCs) in osteogenic culture. The cells adhered and proliferated on the silk/clay composites over two weeks. Quantitative real-time RT-PCR analysis revealed increased transcript levels for alkaline phosphatase (ALP), bone sialoprotein (BSP), and collagen type 1 (Col I) osteogenic markers in the cells cultured on the silk/clay films in comparison to the controls. Early evidence for bone formation based on collagen deposition at the cell-biomaterial interface was also found, with more collagen observed for the silk films with higher contents of clay particles. The data suggest that the silk/clay composite systems may be useful for further study toward bone regenerative needs. PMID:21549864

  10. BMP2-coprecipitated calcium phosphate granules enhance osteoinductivity of deproteinized bovine bone, and bone formation during critical-sized bone defect healing.

    PubMed

    Liu, Tie; Zheng, Yuanna; Wu, Gang; Wismeijer, Daniel; Pathak, Janak L; Liu, Yuelian

    2017-01-31

    Most materials used clinically for filling critical-sized bone defects (CSBD), such as deproteinized bovine bone (DBB), lack osteoinductivity so that their therapeutic effects are far from satisfactory. The effect of bone morphogenic protein 2 (BMP2)-coprecipitated biomimetic calcium phosphate granules (BMP2-cop.BioCaP) on osteoinduction of DBB graft(s) during CSBD healing is still unknown. We investigated whether BMP2-cop.BioCaP affects the osteoinductivity of DBB, bone formation, and foreign body reaction during CSBD healing. DBB + BMP2-cop.BioCaP, DBB, DBB + BMP2, DBB + BioCaP, and autologous bone grafts were implanted in the CSBD of sheep. Bone formation, DBB/BioCaP degradability, foreign body reaction, and osteoinductivity of DBB were analyzed histologically and histomorphometrically at week 4 and 8. Combination of BMP2-cop.BioCaP and DBB healed CSBD as effectively as autologous bone grafts. About 95% of the BMP2-cop.BioCaP had been degraded and replaced by new bone at week 8 in the DBB + BMP2-cop.BioCaP-group. Foreign body reaction was reduced in the DBB + BMP2-cop.BioCaP-group compared to the other groups. The independent use of the BMP2-cop.BioCaP did not achieve a satisfactory bone repair. In conclusion, the BMP2-cop.BioCaP showed good degradability and biocompatibility, and enhanced osteoinductivity of DBB during CSBD healing in sheep, suggesting BMP2-cop.BioCaP as a potential osteoinducer to enhance the therapeutic effects of the graft materials in clinic.

  11. BMP2-coprecipitated calcium phosphate granules enhance osteoinductivity of deproteinized bovine bone, and bone formation during critical-sized bone defect healing

    PubMed Central

    Liu, Tie; Zheng, Yuanna; Wu, Gang; Wismeijer, Daniel; Pathak, Janak L.; Liu, Yuelian

    2017-01-01

    Most materials used clinically for filling critical-sized bone defects (CSBD), such as deproteinized bovine bone (DBB), lack osteoinductivity so that their therapeutic effects are far from satisfactory. The effect of bone morphogenic protein 2 (BMP2)-coprecipitated biomimetic calcium phosphate granules (BMP2-cop.BioCaP) on osteoinduction of DBB graft(s) during CSBD healing is still unknown. We investigated whether BMP2-cop.BioCaP affects the osteoinductivity of DBB, bone formation, and foreign body reaction during CSBD healing. DBB + BMP2-cop.BioCaP, DBB, DBB + BMP2, DBB + BioCaP, and autologous bone grafts were implanted in the CSBD of sheep. Bone formation, DBB/BioCaP degradability, foreign body reaction, and osteoinductivity of DBB were analyzed histologically and histomorphometrically at week 4 and 8. Combination of BMP2-cop.BioCaP and DBB healed CSBD as effectively as autologous bone grafts. About 95% of the BMP2-cop.BioCaP had been degraded and replaced by new bone at week 8 in the DBB + BMP2-cop.BioCaP-group. Foreign body reaction was reduced in the DBB + BMP2-cop.BioCaP-group compared to the other groups. The independent use of the BMP2-cop.BioCaP did not achieve a satisfactory bone repair. In conclusion, the BMP2-cop.BioCaP showed good degradability and biocompatibility, and enhanced osteoinductivity of DBB during CSBD healing in sheep, suggesting BMP2-cop.BioCaP as a potential osteoinducer to enhance the therapeutic effects of the graft materials in clinic. PMID:28139726

  12. Induction of de novo bone formation in the beagle. A novel effect of aluminum.

    PubMed Central

    Quarles, L D; Gitelman, H J; Drezner, M K

    1988-01-01

    To define the primary effects of aluminum on bone in the mammalian species, we examined the dose/time-dependent actions of aluminum in normal beagles. Administration of low dose aluminum (0.75 mg/kg) significantly elevated the serum aluminum (151.7 +/- 19.9 micrograms/liter) compared with that in controls (4.2 +/- 1.35 micrograms/liter) but did not alter the calcium, creatinine, or parathyroid hormone. After 8 wk of therapy, bone biopsies displayed reduced bone resorption (2.6 +/- 0.63 vs. 4.5 +/- 0.39%) and osteoblast covered bone surfaces (2.02 +/- 0.51 vs. 7.64 +/- 1.86%), which was indicative of low turnover. In contrast, prolonged treatment resulted in increased bone volume and trabecular number (38.9 +/- 1.35 vs. 25.2 +/- 2.56% and 3.56 +/- 0.23 vs. 2.88 +/- 0.11/mm) which was consistent with uncoupled bone formation. Administration of higher doses of aluminum (1.20 mg/kg) increased the serum aluminum further (1242.3 +/- 259.8 micrograms/liter) but did not affect calcium, creatinine, or parathyroid hormone. However, after 8 wk of treatment, bone biopsies displayed changes similar to those after long-term, low-dose therapy. In this regard, an increased trabecular number (3.41 +/- 0.18/mm) and bone volume (36.5 +/- 2.38%) again provided evidence of uncoupled bone formation. In contrast, in this instance poorly mineralized woven bone contributed to the enhanced bone volume. High-dose treatment for 16 wk further enhanced bone volume (50.4 +/- 4.61%) and trabecular number (3.90 +/- 0.5/mm). These observations illustrate that aluminum may stimulate uncoupled bone formation and induce a positive bone balance. This enhancement of bone histogenesis contrasts with the effects of pharmacologic agents that alter the function of existing bone remodeling units. Images PMID:3350964

  13. Appositional bone formation in marginal defects at implants.

    PubMed

    Botticelli, Daniele; Berglundh, Tord; Buser, Daniel; Lindhe, Jan

    2003-02-01

    In a previous experiment, it was demonstrated that a wide marginal defect around an implant can heal with a high degree of osseointegration. The present experiment was performed to evaluate the degree and quality of de novo bone formation and osseointegration in marginal defects adjacent to submerged titanium implants. All mandibular premolars and 1st molars were extracted in four Labrador dogs. Four experimental sites were identified in the right side of the mandible. In two sites, custom-made implants with a sandblasted, large grit, acid-etched (SLA) surface were installed without further ostectomy (control sites). In the two remaining sites (test sites), a specially designed step drill was used to widen the marginal 5 mm of the canal. A barrier membrane was used to cover the implants in the defect sites. All implants were submerged. One month later, an identical procedure, including site preparation and implant installation, was performed in the left side of the mandible. Two months following the first implant installation procedure, biopsies were collected and prepared for sectioning. Ostectomy and implant installation in the control location resulted in a series of bone tissue alterations which eventually allowed newly formed bone to establish contact with the SLA surface. The marginal defect lateral to the implant in the test locations gradually became filled with newly formed bone. De novo bone formation started within the walls of the surgically prepared defect. Bone-to-implant contact was first established in the apical portion of the gap. This new bone tissue was in the coronal direction continuous with a dense, non-mineralized 'implant attached' soft tissue which, over time, also became mineralized to increase the height of the zone of bone-to-implant contact. The results suggest that healing of a wide marginal defect around an implant is characterized by appositional bone growth from the lateral and apical bone walls of the defect.

  14. Roles of the kidney in the formation, remodeling and repair of bone.

    PubMed

    Wei, Kai; Yin, Zhiwei; Xie, Yuansheng

    2016-06-01

    The relationship between the kidney and bone is highly complex, and the kidney plays an important role in the regulation of bone development and metabolism. The kidney is the major organ involved in the regulation of calcium and phosphate homeostasis, which is essential for bone mineralization and development. Many substances synthesized by the kidney, such as 1,25(OH)2D3, Klotho, bone morphogenetic protein-7, and erythropoietin, are involved in different stages of bone formation, remodeling and repair. In addition, some cytokines which can be affected by the kidney, such as osteoprotegerin, sclerostin, fibroblast growth factor -23 and parathyroid hormone, also play important roles in bone metabolism. In this paper, we summarize the possible effects of these kidney-related cytokines on bone and their possible mechanisms. Most of these cytokines can interact with one another, constituting an intricate network between the kidney and bone. Therefore, kidney diseases should be considered among patients presenting with osteodystrophy and disturbances in bone and mineral metabolism, and treatment for renal dysfunction may accelerate their recovery.

  15. Bone density, strength, and formation in adult cathepsin K (-/-) mice.

    PubMed

    Pennypacker, B; Shea, M; Liu, Q; Masarachia, P; Saftig, P; Rodan, S; Rodan, G; Kimmel, D

    2009-02-01

    Cathepsin K (CatK) is a cysteine protease expressed predominantly in osteoclasts, that plays a prominent role in degrading Type I collagen. Growing CatK null mice have osteopetrosis associated with a reduced ability to degrade bone matrix. Bone strength and histomorphometric endpoints in young adult CatK null mice aged more than 10 weeks have not been studied. The purpose of this paper is to describe bone mass, strength, resorption, and formation in young adult CatK null mice. In male and female wild-type (WT), heterozygous, and homozygous CatK null mice (total N=50) aged 19 weeks, in-life double fluorochrome labeling was performed. Right femurs and lumbar vertebral bodies 1-3 (LV) were evaluated by dual-energy X-ray absorptiometry (DXA) for bone mineral content (BMC) and bone mineral density (BMD). The trabecular region of the femur and the cortical region of the tibia were evaluated by histomorphometry. The left femur and sixth lumbar vertebral body were tested biomechanically. CatK (-/-) mice show higher BMD at the central and distal femur. Central femur ultimate load was positively influenced by genotype, and was positively correlated with both cortical area and BMC. Lumbar vertebral body ultimate load was also positively correlated to BMC. Genotype did not influence the relationship of ultimate load to BMC in either the central femur or vertebral body. CatK (-/-) mice had less lamellar cortical bone than WT mice. Higher bone volume, trabecular thickness, and trabecular number were observed at the distal femur in CatK (-/-) mice. Smaller marrow cavities were also present at the central femur of CatK (-/-) mice. CatK (-/-) mice exhibited greater trabecular mineralizing surface, associated with normal volume-based formation of trabecular bone. Adult CatK (-/-) mice have higher bone mass in both cortical and cancellous regions than WT mice. Though no direct measures of bone resorption rate were made, the higher cortical bone quantity is associated with a smaller

  16. Genetic Dissection of a QTL Affecting Bone Geometry

    PubMed Central

    Sabik, Olivia L.; Medrano, Juan F.; Farber, Charles R.

    2017-01-01

    Parameters of bone geometry such as width, length, and cross-sectional area are major determinants of bone strength. Although these traits are highly heritable, few genes influencing bone geometry have been identified. Here, we dissect a major quantitative trait locus (QTL) influencing femur size. This QTL was originally identified in an F2 cross between the C57BL/6J-hg/hg (HG) and CAST/EiJ strains and was referred to as femur length in high growth mice 2 (Feml2). Feml2 was located on chromosome (Chr.) 9 at ∼20 cM. Here, we show that the HG.CAST-(D9Mit249-D9Mit133)/Ucd congenic strain captures Feml2. In an F2 congenic cross, we fine-mapped the location of Feml2 to an ∼6 Mbp region extending from 57.3 to 63.3 Mbp on Chr. 9. We have identified candidates by mining the complete genome sequence of CAST/EiJ and through allele-specific expression (ASE) analysis of growth plates in C57BL/6J × CAST/EiJ F1 hybrids. Interestingly, we also find that the refined location of Feml2 overlaps a cluster of six independent genome-wide associations for human height. This work provides the foundation for the identification of novel genes affecting bone geometry. PMID:28082324

  17. Genetic Dissection of a QTL Affecting Bone Geometry.

    PubMed

    Sabik, Olivia L; Medrano, Juan F; Farber, Charles R

    2017-03-10

    Parameters of bone geometry such as width, length, and cross-sectional area are major determinants of bone strength. Although these traits are highly heritable, few genes influencing bone geometry have been identified. Here, we dissect a major quantitative trait locus (QTL) influencing femur size. This QTL was originally identified in an F2 cross between the C57BL/6J-hg/hg (HG) and CAST/EiJ strains and was referred to as femur length in high growth mice 2 (Feml2). Feml2 was located on chromosome (Chr.) 9 at ∼20 cM. Here, we show that the HG.CAST-(D9Mit249-D9Mit133)/Ucd congenic strain captures Feml2 In an F2 congenic cross, we fine-mapped the location of Feml2 to an ∼6 Mbp region extending from 57.3 to 63.3 Mbp on Chr. 9. We have identified candidates by mining the complete genome sequence of CAST/EiJ and through allele-specific expression (ASE) analysis of growth plates in C57BL/6J × CAST/EiJ F1 hybrids. Interestingly, we also find that the refined location of Feml2 overlaps a cluster of six independent genome-wide associations for human height. This work provides the foundation for the identification of novel genes affecting bone geometry.

  18. Non-Linear Pattern Formation in Bone Growth and Architecture

    PubMed Central

    Salmon, Phil

    2014-01-01

    The three-dimensional morphology of bone arises through adaptation to its required engineering performance. Genetically and adaptively bone travels along a complex spatiotemporal trajectory to acquire optimal architecture. On a cellular, micro-anatomical scale, what mechanisms coordinate the activity of osteoblasts and osteoclasts to produce complex and efficient bone architectures? One mechanism is examined here – chaotic non-linear pattern formation (NPF) – which underlies in a unifying way natural structures as disparate as trabecular bone, swarms of birds flying, island formation, fluid turbulence, and others. At the heart of NPF is the fact that simple rules operating between interacting elements, and Turing-like interaction between global and local signals, lead to complex and structured patterns. The study of “group intelligence” exhibited by swarming birds or shoaling fish has led to an embodiment of NPF called “particle swarm optimization” (PSO). This theoretical model could be applicable to the behavior of osteoblasts, osteoclasts, and osteocytes, seeing them operating “socially” in response simultaneously to both global and local signals (endocrine, cytokine, mechanical), resulting in their clustered activity at formation and resorption sites. This represents problem-solving by social intelligence, and could potentially add further realism to in silico computer simulation of bone modeling. What insights has NPF provided to bone biology? One example concerns the genetic disorder juvenile Pagets disease or idiopathic hyperphosphatasia, where the anomalous parallel trabecular architecture characteristic of this pathology is consistent with an NPF paradigm by analogy with known experimental NPF systems. Here, coupling or “feedback” between osteoblasts and osteoclasts is the critical element. This NPF paradigm implies a profound link between bone regulation and its architecture: in bone the architecture is the regulation. The former is the

  19. Non-linear pattern formation in bone growth and architecture.

    PubMed

    Salmon, Phil

    2014-01-01

    The three-dimensional morphology of bone arises through adaptation to its required engineering performance. Genetically and adaptively bone travels along a complex spatiotemporal trajectory to acquire optimal architecture. On a cellular, micro-anatomical scale, what mechanisms coordinate the activity of osteoblasts and osteoclasts to produce complex and efficient bone architectures? One mechanism is examined here - chaotic non-linear pattern formation (NPF) - which underlies in a unifying way natural structures as disparate as trabecular bone, swarms of birds flying, island formation, fluid turbulence, and others. At the heart of NPF is the fact that simple rules operating between interacting elements, and Turing-like interaction between global and local signals, lead to complex and structured patterns. The study of "group intelligence" exhibited by swarming birds or shoaling fish has led to an embodiment of NPF called "particle swarm optimization" (PSO). This theoretical model could be applicable to the behavior of osteoblasts, osteoclasts, and osteocytes, seeing them operating "socially" in response simultaneously to both global and local signals (endocrine, cytokine, mechanical), resulting in their clustered activity at formation and resorption sites. This represents problem-solving by social intelligence, and could potentially add further realism to in silico computer simulation of bone modeling. What insights has NPF provided to bone biology? One example concerns the genetic disorder juvenile Pagets disease or idiopathic hyperphosphatasia, where the anomalous parallel trabecular architecture characteristic of this pathology is consistent with an NPF paradigm by analogy with known experimental NPF systems. Here, coupling or "feedback" between osteoblasts and osteoclasts is the critical element. This NPF paradigm implies a profound link between bone regulation and its architecture: in bone the architecture is the regulation. The former is the emergent

  20. Bone mineral density-affecting genes in Africans.

    PubMed Central

    Gong, Gordon; Haynatzki, Gleb; Haynatzka, Vera; Howell, Ryan; Kosoko-Lasaki, Sade; Fu, Yun-Xin; Yu, Fei; Gallagher, John C.; Wilson, M. Roy

    2006-01-01

    BACKGROUND: We have recently reported the role of environmental exposure in the ethnic diversity of bone mineral density (BMD). Potential genetic difference has not been adequately assessed. PURPOSE: To determine allele frequencies of BMD-affecting genes and their association with BMD in Africans. METHODS: Allele frequencies at 18 polymorphic sites in 13 genes that affect BMD in Asians and/or Caucasians were determined in 143 recent immigrants (55 men and 88 women, 18-51 years of age) from sub-Saharan Sudan to the United States. Genetic association studies were performed. RESULTS: Among the 14 single-nucleotide polymorphisms (SNPs), 10 were significantly different in allele frequency between Sudanese and Asians, and 10 between Sudanese and Caucasians. Only the osteocalcin gene was not significantly different in allele frequency among Sudanese, Asians and Caucasians. Allele frequencies in the TGFB, COL1A1 and CSR genes were extremely low (<0.04) in the Sudanese. Frequencies of microsatellite alleles in four genes were significantly different among Sudanese, Asians and Caucasians. SNPs in the VDR and ERalpha genes were associated with BMD and/or BMC (bone mineral content) at several bone sites. CONCLUSIONS: Genetic difference may play a role in the ethnic diversity in BMD and/or BMC. PMID:16895279

  1. Osteoclast precursor interaction with bone matrix induces osteoclast formation directly by an interleukin-1-mediated autocrine mechanism.

    PubMed

    Yao, Zhenqiang; Xing, Lianping; Qin, Chunlin; Schwarz, Edward M; Boyce, Brendan F

    2008-04-11

    Interleukin-1 (IL-1) and tumor necrosis factor (TNF) mediate bone resorption in a variety of diseases affecting bone. Like TNF, IL-1 is secreted by osteoclast precursors (OCPs), but unlike TNF, it does not induce osteoclast formation directly from OCPs in vitro. TNF induces IL-1 expression and activates c-Fos, a transcription factor required in OCPs for osteoclast formation. Here, we examined whether IL-1 can induce osteoclast formation directly from OCPs overexpressing c-Fos and whether interaction with bone matrix affects OCP cytokine expression. We infected OCPs with c-Fos or green fluorescent protein retrovirus, cultured them with macrophage colony-stimulating factor and IL-1 on bone slices or plastic dishes, and assessed osteoclast and resorption pit formation and expression of IL-1 by OCPs. We used a Transwell assay to determine whether OCPs secrete IL-1 when they interact with bone matrix. IL-1 induced osteoclast formation directly from c-Fos-expressing OCPs on plastic. c-Fos-expressing OCPs formed osteoclasts spontaneously on bone slices without addition of cytokines. OCPs on bone secreted IL-1, which induced osteoclast formation from c-Fos-expressing OCPs in the lower Transwell dishes. The bone matrix proteins dentin sialoprotein and osteopontin, but not transforming growth factor-beta, stimulated OCP expression of IL-1 and induced c-Fos-expressing OCP differentiation into osteoclasts. Osteoclasts eroding inflamed joints have higher c-Fos expression compared with osteoclasts inside bone. We conclude that OCPs expressing c-Fos may induce their differentiation directly into osteoclasts by an autocrine mechanism in which they produce IL-1 through interaction with bone matrix. TNF could induce c-Fos expression in OCPs at sites of inflammation in bone to promote this autocrine mechanism and thus amplify bone loss.

  2. Repeated freeze-thawing of bone tissue affects Raman bone quality measurements

    PubMed Central

    McElderry, John-David P.; Kole, Matthew R.; Morris, Michael D.

    2011-01-01

    The ability to probe fresh tissue is a key feature to biomedical Raman spectroscopy. However, it is unclear how Raman spectra of calcified tissues are affected by freezing. In this study, six transverse sections of femoral cortical bone were subjected to multiple freeze/thaw cycles and probed using a custom Raman microscope. Significant decreases were observed in the amide I and amide III bands starting after two freeze thaw cycles. Raman band intensities arising from proline residues of frozen tissue appeared consistent with fresh tissue after four cycles. Crystallinity values of bone mineral diminished slightly with freezing and were noticeable after only one freezing. Mineral carbonate levels did not deviate significantly with freezing and thawing. The authors recommend freezing and thawing bone tissue only once to maintain accurate results. PMID:21806253

  3. Vibration acceleration promotes bone formation in rodent models

    PubMed Central

    Uchida, Ryohei; Nakata, Ken; Kawano, Fuminori; Yonetani, Yasukazu; Ogasawara, Issei; Nakai, Naoya; Mae, Tatsuo; Matsuo, Tomohiko; Tachibana, Yuta; Yokoi, Hiroyuki; Yoshikawa, Hideki

    2017-01-01

    All living tissues and cells on Earth are subject to gravitational acceleration, but no reports have verified whether acceleration mode influences bone formation and healing. Therefore, this study was to compare the effects of two acceleration modes, vibration and constant (centrifugal) accelerations, on bone formation and healing in the trunk using BMP 2-induced ectopic bone formation (EBF) mouse model and a rib fracture healing (RFH) rat model. Additionally, we tried to verify the difference in mechanism of effect on bone formation by accelerations between these two models. Three groups (low- and high-magnitude vibration and control-VA groups) were evaluated in the vibration acceleration study, and two groups (centrifuge acceleration and control-CA groups) were used in the constant acceleration study. In each model, the intervention was applied for ten minutes per day from three days after surgery for eleven days (EBF model) or nine days (RFH model). All animals were sacrificed the day after the intervention ended. In the EBF model, ectopic bone was evaluated by macroscopic and histological observations, wet weight, radiography and microfocus computed tomography (micro-CT). In the RFH model, whole fracture-repaired ribs were excised with removal of soft tissue, and evaluated radiologically and histologically. Ectopic bones in the low-magnitude group (EBF model) had significantly greater wet weight and were significantly larger (macroscopically and radiographically) than those in the other two groups, whereas the size and wet weight of ectopic bones in the centrifuge acceleration group showed no significant difference compared those in control-CA group. All ectopic bones showed calcified trabeculae and maturated bone marrow. Micro-CT showed that bone volume (BV) in the low-magnitude group of EBF model was significantly higher than those in the other two groups (3.1±1.2mm3 v.s. 1.8±1.2mm3 in high-magnitude group and 1.3±0.9mm3 in control-VA group), but BV in the

  4. Osteocyte-derived HB-GAM (pleiotrophin) is associated with bone formation and mechanical loading.

    PubMed

    Imai, S; Heino, T J; Hienola, A; Kurata, K; Büki, K; Matsusue, Y; Väänänen, H K; Rauvala, H

    2009-05-01

    HB-GAM (also known as pleiotrophin) is a cell matrix-associated protein that is highly expressed in bone. It affects osteoblast function, and might therefore play a role in bone development and remodeling. We aimed to investigate the role of HB-GAM in bone in vivo and in vitro. The bones of HB-GAM deficient mice with an inbred mouse background were studied by histological, histomorphometrical, radiological, biomechanical and mu-CT analyses and the effect of immobilization was evaluated. HB-GAM localization in vivo was studied. MLO-Y4 osteocytes were subjected to fluid shear stress in vitro, and gene and protein expression were studied by subtractive hybridization, quantitative PCR and Western blot. Human osteoclasts were cultured in the presence of rhHB-GAM and their formation and resorption activities were assayed. In agreement with previous reports, the skeletal structure of the HB-GAM knockout mice developed normally. However, a growth retardation of the weight-bearing bones was observed by 2 months of age, suggesting a link to physical activity. Adult HB-GAM deficient mice were characterized by low bone formation and osteopenia, as well as resistance to immobilization-dependent bone remodeling. HB-GAM was localized around osteocytes and their processes in vivo and furthermore, osteocytic HB-GAM expression was upregulated by mechanical loading in vitro. HB-GAM did not affect on human osteoclast formation or resorption in vitro. Taken together, our results suggest that HB-GAM is an osteocyte-derived factor that could participate in mediating the osteogenic effects of mechanical loading on bone.

  5. Thyrostimulin Regulates Osteoblastic Bone Formation During Early Skeletal Development

    PubMed Central

    van der Spek, Anne; Logan, John G.; Gogakos, Apostolos; Bagchi-Chakraborty, Jayashree; Murphy, Elaine; van Zeijl, Clementine; Down, Jenny; Croucher, Peter I.; Boyde, Alan; Boelen, Anita

    2015-01-01

    The ancestral glycoprotein hormone thyrostimulin is a heterodimer of unique glycoprotein hormone subunit alpha (GPA)2 and glycoprotein hormone subunit beta (GPB)5 subunits with high affinity for the TSH receptor. Transgenic overexpression of GPB5 in mice results in cranial abnormalities, but the role of thyrostimulin in bone remains unknown. We hypothesized that thyrostimulin exerts paracrine actions in bone and determined: 1) GPA2 and GPB5 expression in osteoblasts and osteoclasts, 2) the skeletal consequences of thyrostimulin deficiency in GPB5 knockout (KO) mice, and 3) osteoblast and osteoclast responses to thyrostimulin treatment. Gpa2 and Gpb5 expression was identified in the newborn skeleton but declined rapidly thereafter. GPA2 and GPB5 mRNAs were also expressed in primary osteoblasts and osteoclasts at varying concentrations. Juvenile thyrostimulin-deficient mice had increased bone volume and mineralization as a result of increased osteoblastic bone formation. However, thyrostimulin failed to induce a canonical cAMP response or activate the noncanonical Akt, ERK, or mitogen-activated protein kinase (P38) signaling pathways in primary calvarial or bone marrow stromal cell-derived osteoblasts. Furthermore, thyrostimulin did not directly inhibit osteoblast proliferation, differentiation or mineralization in vitro. These studies identify thyrostimulin as a negative but indirect regulator of osteoblastic bone formation during skeletal development. PMID:26018249

  6. Stromal cell-derived factor-1 potentiates bone morphogenetic protein-2 induced bone formation.

    PubMed

    Higashino, Kosaku; Viggeswarapu, Manjula; Bargouti, Maggie; Liu, Hui; Titus, Louisa; Boden, Scott D

    2011-02-01

    The mechanisms driving bone marrow stem cell mobilization are poorly understood. A recent murine study found that circulating bone marrow-derived osteoprogenitor cells (MOPCs) were recruited to the site of recombinant human bone morphogenetic protein-2 (BMP-2)-induced bone formation. Stromal cell-derived factor-1α (SDF-1α) and its cellular receptor CXCR4 have been shown to mediate the homing of stem cells to injured tissues. We hypothesized that chemokines, such as SDF-1, are also involved with mobilization of bone marrow cells. The CD45(-) fraction is a major source of MOPCs. In this report we determined that the addition of BMP-2 or SDF-1 to collagen implants increased the number of MOPCs in the peripheral blood. BMP-2-induced mobilization was blocked by CXCR4 antibody, confirming the role of SDF-1 in mobilization. We determined for the first time that addition of SDF-1 to implants containing BMP-2 enhances mobilization, homing of MOPCs to the implant, and ectopic bone formation induced by suboptimal BMP-2 doses. These results suggest that SDF-1 increases the number of osteoprogenitor cells that are mobilized from the bone marrow and then home to the implant. Thus, addition of SDF-1 to BMP-2 may improve the efficiency of BMPs in vivo, making their routine use for orthopaedic applications more affordable and available to more patients.

  7. PTH-IGF SIGNALING PROMOTES BONE FORMATION THROUGH GLYCOLYSIS

    PubMed Central

    Esen, Emel; Lee, Seung-Yon; Wice, Burton M; Long, Fanxin

    2016-01-01

    Teriparatide, a recombinant peptide corresponding to amino acids 1-34 of human parathyroid hormone (PTH), has been an effective bone anabolic drug for over a decade. However, the mechanism whereby PTH stimulates bone formation remains poorly understood. Here we report that in cultures of osteoblast-lineage cells, PTH stimulates glucose consumption and lactate production in the presence of oxygen, a hallmark of aerobic glycolysis, also known as Warburg effect. Experiments with radioactively labeled glucose demonstrate that PTH suppresses glucose entry into the tricarboxylic acid cycle (TCA cycle). Mechanistically, the increase in aerobic glycolysis is secondary to insulin-like growth factor (Igf) signaling induced by PTH, whereas the metabolic effect of Igf is dependent on activation of mammalian target of rapamycin complex 2 (mTORC2). Importantly, pharmacological perturbation of glycolysis suppresses the bone anabolic effect of intermittent PTH in the mouse. Thus, stimulation of aerobic glycolysis via Igf signaling contributes to bone anabolism in response to PTH. PMID:25990470

  8. High vitamin D3 diet administered during active colitis negatively affects bone metabolism in an adoptive T cell transfer model

    PubMed Central

    Larmonier, C. B.; McFadden, R.-M. T.; Hill, F. M.; Schreiner, R.; Ramalingam, R.; Besselsen, D. G.; Ghishan, F. K.

    2013-01-01

    Decreased bone mineral density (BMD) represents an extraintestinal complication of inflammatory bowel disease (IBD). Vitamin D3 has been considered a viable adjunctive therapy in IBD. However, vitamin D3 plays a pleiotropic role in bone modeling and regulates the bone formation-resorption balance, depending on the physiological environment, and supplementation during active IBD may have unintended consequences. We evaluated the effects of vitamin D3 supplementation during the active phase of disease on colonic inflammation, BMD, and bone metabolism in an adoptive IL-10−/− CD4+ T cell transfer model of chronic colitis. High-dose vitamin D3 supplementation for 12 days during established disease had negligible effects on mucosal inflammation. Plasma vitamin D3 metabolites correlated with diet, but not disease, status. Colitis significantly reduced BMD. High-dose vitamin D3 supplementation did not affect cortical bone but led to a further deterioration of trabecular bone morphology. In mice fed a high vitamin D3 diet, colitis more severely impacted bone formation markers (osteocalcin and bone alkaline phosphatase) and increased bone resorption markers, ratio of receptor activator of NF-κB ligand to osteoprotegrin transcript, plasma osteoprotegrin level, and the osteoclast activation marker tartrate-resistant acid phosphatase (ACp5). Bone vitamin D receptor expression was increased in mice with chronic colitis, especially in the high vitamin D3 group. Our data suggest that vitamin D3, at a dose that does not improve inflammation, has no beneficial effects on bone metabolism and density during active colitis or may adversely affect BMD and bone turnover. These observations should be taken into consideration in the planning of further clinical studies with high-dose vitamin D3 supplementation in patients with active IBD. PMID:23639807

  9. Zebrafish Bone and General Physiology Are Differently Affected by Hormones or Changes in Gravity.

    PubMed

    Aceto, Jessica; Nourizadeh-Lillabadi, Rasoul; Marée, Raphael; Dardenne, Nadia; Jeanray, Nathalie; Wehenkel, Louis; Aleström, Peter; van Loon, Jack J W A; Muller, Marc

    2015-01-01

    Teleost fish such as zebrafish (Danio rerio) are increasingly used for physiological, genetic and developmental studies. Our understanding of the physiological consequences of altered gravity in an entire organism is still incomplete. We used altered gravity and drug treatment experiments to evaluate their effects specifically on bone formation and more generally on whole genome gene expression. By combining morphometric tools with an objective scoring system for the state of development for each element in the head skeleton and specific gene expression analysis, we confirmed and characterized in detail the decrease or increase of bone formation caused by a 5 day treatment (from 5dpf to 10 dpf) of, respectively parathyroid hormone (PTH) or vitamin D3 (VitD3). Microarray transcriptome analysis after 24 hours treatment reveals a general effect on physiology upon VitD3 treatment, while PTH causes more specifically developmental effects. Hypergravity (3g from 5dpf to 9 dpf) exposure results in a significantly larger head and a significant increase in bone formation for a subset of the cranial bones. Gene expression analysis after 24 hrs at 3g revealed differential expression of genes involved in the development and function of the skeletal, muscular, nervous, endocrine and cardiovascular systems. Finally, we propose a novel type of experimental approach, the "Reduced Gravity Paradigm", by keeping the developing larvae at 3g hypergravity for the first 5 days before returning them to 1g for one additional day. 5 days exposure to 3g during these early stages also caused increased bone formation, while gene expression analysis revealed a central network of regulatory genes (hes5, sox10, lgals3bp, egr1, edn1, fos, fosb, klf2, gadd45ba and socs3a) whose expression was consistently affected by the transition from hyper- to normal gravity.

  10. Zebrafish Bone and General Physiology Are Differently Affected by Hormones or Changes in Gravity

    PubMed Central

    Aceto, Jessica; Nourizadeh-Lillabadi, Rasoul; Marée, Raphael; Dardenne, Nadia; Jeanray, Nathalie; Wehenkel, Louis; Aleström, Peter

    2015-01-01

    Teleost fish such as zebrafish (Danio rerio) are increasingly used for physiological, genetic and developmental studies. Our understanding of the physiological consequences of altered gravity in an entire organism is still incomplete. We used altered gravity and drug treatment experiments to evaluate their effects specifically on bone formation and more generally on whole genome gene expression. By combining morphometric tools with an objective scoring system for the state of development for each element in the head skeleton and specific gene expression analysis, we confirmed and characterized in detail the decrease or increase of bone formation caused by a 5 day treatment (from 5dpf to 10 dpf) of, respectively parathyroid hormone (PTH) or vitamin D3 (VitD3). Microarray transcriptome analysis after 24 hours treatment reveals a general effect on physiology upon VitD3 treatment, while PTH causes more specifically developmental effects. Hypergravity (3g from 5dpf to 9 dpf) exposure results in a significantly larger head and a significant increase in bone formation for a subset of the cranial bones. Gene expression analysis after 24 hrs at 3g revealed differential expression of genes involved in the development and function of the skeletal, muscular, nervous, endocrine and cardiovascular systems. Finally, we propose a novel type of experimental approach, the "Reduced Gravity Paradigm", by keeping the developing larvae at 3g hypergravity for the first 5 days before returning them to 1g for one additional day. 5 days exposure to 3g during these early stages also caused increased bone formation, while gene expression analysis revealed a central network of regulatory genes (hes5, sox10, lgals3bp, egr1, edn1, fos, fosb, klf2, gadd45ba and socs3a) whose expression was consistently affected by the transition from hyper- to normal gravity. PMID:26061167

  11. Effects Of Stress On Bone-Formation Markers In Rats

    NASA Technical Reports Server (NTRS)

    Arnaud, Sara B.; Fung, Paul; Vasques, Marilyn; Grindeland, Richard E.; Patterson-Buckendahl, Patricia; Durnova, Galina

    1992-01-01

    Report describes experiments involving simultaneous measurement of concentrations, in blood, of two substances indicative of formation of bone in rats. Measurements performed after flight in outer space plus 48 h of postflight environmental stress. Results emphasize critical influences of adrenal status and diet on functions of osteoblasts.

  12. Demineralized Bone Matrix Injection in Consolidation Phase Enhances Bone Regeneration in Distraction Osteogenesis via Endochondral Bone Formation

    PubMed Central

    Kim, Ji-Beom; Seo, Sang Gyo; Kim, Eo Jin; Kim, Ji Hye; Yoo, Won Joon; Cho, Tae-Joon; Choi, In Ho

    2015-01-01

    Background Distraction osteogenesis (DO) is a promising tool for bone and tissue regeneration. However, prolonged healing time remains a major problem. Various materials including cells, cytokines, and growth factors have been used in an attempt to enhance bone formation. We examined the effect of percutaneous injection of demineralized bone matrix (DBM) during the consolidation phase on bone regeneration after distraction. Methods The immature rabbit tibial DO model (20 mm length-gain) was used. Twenty-eight animals received DBM 100 mg percutaneously at the end of distraction. Another 22 animals were left without further procedure (control). Plain radiographs were taken every week. Postmortem bone dual-energy X-ray absorptiometry and micro-computed tomography (micro-CT) studies were performed at the third and sixth weeks of the consolidation period and histological analysis was performed. Results The regenerate bone mineral density was higher in the DBM group when compared with that in the saline injection control group at the third week postdistraction. Quantitative analysis using micro-CT revealed larger trabecular bone volume, higher trabecular number, and less trabecular separation in the DBM group than in the saline injection control group. Cross-sectional area and cortical thickness at the sixth week postdistraction, assessed using micro-CT, were greater in the regenerates of the DBM group compared with the control group. Histological evaluation revealed higher trabecular bone volume and trabecular number in the regenerate of the DBM group. New bone formation was apparently enhanced, via endochondral ossification, at the site and in the vicinity of the injected DBM. DBM was absorbed slowly, but it remained until the sixth postoperative week after injection. Conclusions DBM administration into the distraction gap at the end of the distraction period resulted in a significantly greater regenerate bone area, trabecular number, and cortical thickness in the

  13. A report from Fukushima: an assessment of bone health in an area affected by the Fukushima nuclear plant incident.

    PubMed

    Ishii, Takeaki; Ito, Kazuo; Kato, Shigeaki; Tsubokura, Masaharu; Ochi, Sae; Iwamoto, Yukihide; Saito, Yasutoshi

    2013-11-01

    Bone health was assessed for inhabitants of an area affected by the Fukushima nuclear plant incident. Osteoporotic patients, who had been treated with active vitamin D3 and/or bisphosphonate at Soma Central Hospital before the Fukushima incident, were enrolled. Changes in bone turnover markers and bone mineral density were retrospectively analyzed. Serum levels of a bone resorption marker, serum type I collagen cross-linked N-telopeptide were decreased in all the treated groups, whereas those of a bone formation marker, bone-specific alkaline phosphatase, were increased. Accordingly, bone mineral density, estimated by dual-energy X-ray absorptiometry, was increased in the lumbar spine of all groups, but bone mass increase in the proximal femur was detected only in the group treated with the two agents in combination. From the degree of these parameter changes, the antiosteoporotic treatments looked effective and were equivalent to the expected potency of past observations. At this stage, the present study implies that the Fukushima nuclear incident did not bring an acute risk to bone health in the affected areas.

  14. Surface microcracks signal osteoblasts to regulate alignment and bone formation

    PubMed Central

    Shu, Yutian; Baumann, Melissa J.; Case, Eldon D.; Irwin, Regina K.; Meyer, Sarah E.; Pearson, Craig S.; McCabe, Laura R.

    2014-01-01

    Microcracks are present in bone and can result from fatigue damage due to repeated, cyclically applied stresses. From a mechanical point, microcracks can dissipate strain energy at the advancing tip of a crack to improve overall bone toughness. Physiologically, microcracks are thought to trigger bone remodeling. Here, we examine the effect of microcracks specifically on osteoblasts, which are bone-forming cells, by comparing cell responses on microcracked versus non-microcracked hydroxyapatite (HA) specimens. Osteoblast attachment was found to be greater on microcracked HA specimens (p<0.05). More importantly, we identified the preferential alignment of osteoblasts in the direction of the microcracks on HA. Cells also displayed a preferential attachment that was 75 to 90 μm away from the microcrack indent. After 21 days of culture, osteoblast maturation was notably enhanced on the HA with microcracks, as indicated by increased alkaline phosphatase activity and gene expression. Furthermore, examination of bone deposition by confocal laser scanning microscope indicated preferential mineralization at microcrack indentation sites. Dissolution studies indicate that the microcracks increase calcium release, which could contribute to osteoblast responses. Our findings suggest that microcracks signal osteoblast attachment and bone formation/healing. PMID:25280696

  15. Immunolocalization of markers for bone formation during guided bone regeneration in osteopenic rats

    PubMed Central

    TERA, Tábata de Mello; NASCIMENTO, Rodrigo Dias; do PRADO, Renata Falchete; SANTAMARIA, Mauro Pedrine; JARDINI, Maria Aparecida Neves

    2014-01-01

    Objective The aim of this paper was to evaluate the repair of onlay autogenous bone grafts covered or not covered by an expanded polytetrafluoroethylene (e-PTFE) membrane using immunohistochemistry in rats with induced estrogen deficiency. Material and Methods Eighty female rats were randomly divided into two groups: ovariectomized (OVX) and with a simulation of the surgical procedure (SHAM). Each of these groups was again divided into groups with either placement of an autogenous bone graft alone (BG) or an autogenous bone graft associated with an e-PTFE membrane (BGM). Animals were euthanized on days 0, 7, 21, 45, and 60. The specimens were subjected to immunohistochemistry for bone sialoprotein (BSP), osteonectin (ONC), and osteocalcin (OCC). Results All groups (OVX+BG, OVX+BMG, SHAM+BG, and SHAM+BMG) showed greater bone formation, observed between 7 and 21 days, when BSP and ONC staining were more intense. At the 45-day, the bone graft showed direct bonding to the recipient bed in all specimens. The ONC and OCC showed more expressed in granulation tissue, in the membrane groups, independently of estrogen deficiency. Conclusions The expression of bone forming markers was not negatively influenced by estrogen deficiency. However, the markers could be influenced by the presence of the e-PTFE membrane. PMID:25591022

  16. Progress in spondylarthritis. Mechanisms of new bone formation in spondyloarthritis.

    PubMed

    Lories, Rik J U; Luyten, Frank P; de Vlam, Kurt

    2009-01-01

    Targeted therapies that neutralize tumour necrosis factor are often able to control the signs and symptoms of spondyloarthritis. However, recent animal model data and clinical observations indicate that control of inflammation may not be sufficient to impede disease progression toward ankylosis in these patients. Bone morphogenetic proteins and WNTs (wingless-type like) are likely to play an important role in ankylosis and could be therapeutic targets. The relationship between inflammation and new bone formation is still unclear. This review summarizes progress made in our understanding of ankylosis and offers an alternative view of the relationship between inflammation and ankylosis.

  17. Role of nitric oxide and prostaglandins in the bone formation response to mechanical loading.

    PubMed

    Chow, J W

    2000-10-01

    Nitric oxide and prostaglandins are crucial early mediators in mechanically induced bone formation. They are also responsible for the associated induction of gene expression of c-fos and IGF-1 in osteocytes, key mechanosensory cells in bone. Insight into the cellular and molecular mechanisms underlying bone formation has important implications for the maintenance of structural competence of bone.

  18. Serum albumin coating of demineralized bone matrix results in stronger new bone formation.

    PubMed

    Horváthy, Dénes B; Vácz, Gabriella; Szabó, Tamás; Szigyártó, Imola C; Toró, Ildikó; Vámos, Boglárka; Hornyák, István; Renner, Károly; Klára, Tamás; Szabó, Bence T; Dobó-Nagy, Csaba; Doros, Attila; Lacza, Zsombor

    2016-01-01

    Blood serum fractions are hotly debated adjuvants in bone replacement therapies. In the present experiment, we coated demineralized bone matrices (DBM) with serum albumin and investigated stem cell attachment in vitro and bone formation in a rat calvaria defect model. In the in vitro experiments, we observed that significantly more cells adhere to the serum albumin coated DBMs at every time point. In vivo bone formation with albumin coated and uncoated DBM was monitored biweekly by computed tomography until 11 weeks postoperatively while empty defects served as controls. By the seventh week, the bone defect in the albumin group was almost completely closed (remaining defect 3.0 ± 2.3%), while uncoated DBM and unfilled control groups still had significant defects (uncoated: 40.2 ± 9.1%, control: 52.4 ± 8.9%). Higher density values were also observed in the albumin coated DBM group. In addition, the serum albumin enhanced group showed significantly higher volume of newly formed bone in the microCT analysis and produced significantly higher breaking force and stiffness compared to the uncoated grafts (peak breaking force: uncoated: 15.7 ± 4 N, albumin 46.1 ± 11 N). In conclusion, this investigation shows that implanting serum albumin coated DBM significantly reduces healing period in nonhealing defects and results in mechanically stronger bone. These results also support the idea that serum albumin coating provides a convenient milieu for stem cell function, and a much improved bone grafting success can be achieved without the use of exogenous stem cells.

  19. Reduced bone formation and relatively increased bone resorption in absorptive hypercalciuria.

    PubMed

    Heller, H J; Zerwekh, J E; Gottschalk, F A; Pak, C Y C

    2007-04-01

    Absorptive hypercalciuria (AH), a common stone-forming condition characterized biochemically by intestinal hyperabsorption of calcium and hypercalciuria may be associated with bone loss. In AH type I (AH-1), hypercalciuria persists despite restriction in dietary calcium intake. We therefore hypothesized that the skeleton may contribute to the hypercalciuria in this subgroup of patients. Histomorphometric analysis of iliac crest biopsies were performed on nine stone-formers with AH-1 and on nine matched normal subjects. After stabilization on a stone-prevention diet, calcium homeostasis in the stone formers was then evaluated on inpatient constant metabolic diet before and after short-term blockade of bone resorption by alendronate (10 mg daily, 17 days total). Compared with controls, the stone-formers had lower indices of bone formation (osteoblast surface/bone surface 1.8+/-2.1 vs 3.0+/-1.5%, P=0.04; wall thickness 35.8+/-6.9 vs 47.2+/-7.6%, P=0.001) and relatively higher bone resorption (osteoclast surface/bone surface 0.4+/-0.2 vs 0.2+/-0.2%, P=0.05). In the stone-formers, a short-term course of alendronate treatment corrected fasting urinary calcium (0.14+/-0.06 to 0.06+/-0.04 mg Ca/mg Cr, P=0.001) and marginally reduced 24-h urinary calcium by 48 mg/day (P=0.06). Increased intestinal calcium absorption and hypercalciuria persisted, but estimated calcium balance improved (P=0.007). Our results suggest that the hypercalciuria of AH-1 originates primarily from intestinal hyperabsorption of calcium, but bone resorption in excess of bone formation may contribute.

  20. Erythropoietin promotes bone formation through EphrinB2/EphB4 signaling.

    PubMed

    Li, C; Shi, C; Kim, J; Chen, Y; Ni, S; Jiang, L; Zheng, C; Li, D; Hou, J; Taichman, R S; Sun, H

    2015-03-01

    Recent studies have demonstrated that erythropoietin (EPO) has extensive nonhematopoietic biological functions. However, little is known about how EPO regulates bone formation, although several studies suggested that EPO can affect bone homeostasis. In this study, we investigated the effects of EPO on the communication between osteoclasts and osteoblasts through the ephrinB2/EphB4 signaling pathway. We found that EPO slightly promotes osteoblastic differentiation with the increased expression of EphB4 in ST2 cells. However, EPO increased the expression of Nfatc1 and ephrinB2 but decreased the expression of Mmp9 in RAW264.7 cells, resulting in an increase of ephrinB2-expressing osteoclasts and a decrease in resorption activity. The stimulation of ephrinB2/EphB4 signaling via ephrinB2-Fc significantly promoted EPO-mediated osteoblastic differentiation in ST2 cells. EphB4 knockdown through EphB4 shRNA inhibited EPO-mediated osteoblastic phenotypes. Furthermore, in vivo assays clearly demonstrated that EPO efficiently induces new bone formation in the alveolar bone regeneration model. Taken together, these results suggest that ephrinB2/EphB4 signaling may play an important role in EPO-mediated bone formation.

  1. Erythropoietin Promotes Bone Formation through EphrinB2/EphB4 Signaling

    PubMed Central

    Li, C.; Shi, C.; Kim, J.; Chen, Y.; Ni, S.; Jiang, L.; Zheng, C.; Li, D.; Hou, J.; Sun, H.

    2015-01-01

    Recent studies have demonstrated that erythropoietin (EPO) has extensive nonhematopoietic biological functions. However, little is known about how EPO regulates bone formation, although several studies suggested that EPO can affect bone homeostasis. In this study, we investigated the effects of EPO on the communication between osteoclasts and osteoblasts through the ephrinB2/EphB4 signaling pathway. We found that EPO slightly promotes osteoblastic differentiation with the increased expression of EphB4 in ST2 cells. However, EPO increased the expression of Nfatc1 and ephrinB2 but decreased the expression of Mmp9 in RAW264.7 cells, resulting in an increase of ephrinB2-expressing osteoclasts and a decrease in resorption activity. The stimulation of ephrinB2/EphB4 signaling via ephrinB2-Fc significantly promoted EPO-mediated osteoblastic differentiation in ST2 cells. EphB4 knockdown through EphB4 shRNA inhibited EPO-mediated osteoblastic phenotypes. Furthermore, in vivo assays clearly demonstrated that EPO efficiently induces new bone formation in the alveolar bone regeneration model. Taken together, these results suggest that ephrinB2/EphB4 signaling may play an important role in EPO-mediated bone formation. PMID:25586589

  2. Effects of magnetic resonance imaging (MRI) on the formation of mouse dentin and bone

    SciTech Connect

    Kwong-Hing, A.; Sandhu, H.S.; Prato, F.S.; Frappier, J.R.; Kavaliers, M. )

    1989-10-01

    The effects of magnetic resonance imaging (MRI) on dentin and bone formation in mice were examined using standard autoradiographic and liquid scintillation procedures. It was observed that exposure to a standard 23.2 min clinical multislice MRI (0.15T) procedure caused a significant increase in the synthesis of the collagenous matrix of dentin in the incisors of mice. There were no significant effects on alveolar and tibial bone matrix synthesis. These results suggest that the magnetic fields associated with MRI can affect the activity of cells and/or tissues that are involved in rapid synthetic activity.

  3. Transgenic overexpression of bone morphogenetic protein 11 propeptide in skeleton enhances bone formation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bone morphogenetic protein 11 (BMP11) is a key regulatory protein in skeletal development. BMP11 propeptide has been shown to antagonize GDF11 activity in vitro. To explore the role of BMP11 propeptide in skeletal formation in vivo, we generated transgenic mice with skeleton-specific overexpression...

  4. A diet high in meat protein and potential renal acid load increases fractional Ca absorption and urinary Ca excretion, without affecting markers of bone resorption or formation in postmenopausal women

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Objective: The objective was to determine the effects of high dietary protein (mostly meat) and high potential renal acid load (PRAL) on calcium (Ca) balance and markers of bone metabolism. Methods: In a randomized crossover design, sixteen healthy postmenopausal women consumed two diets: one with l...

  5. Bone Formation in Maxillary Sinus Lift Using Autogenous Bone Graft at 2 and 6 Months.

    PubMed

    Netto, Henrique Duque; Miranda Chaves, Maria das Graças Alfonso; Aatrstrup, Beatriz; Guerra, Renata; Olate, Sergio

    2016-09-01

    The aim of this study is to compare the bone formation in maxillary sinus lift with an autogenous bone graft in histological evaluation at 2 or 6 months. A comparative study was designed where 10 patients with missing teeth bilaterally in the posterior zone of the maxilla were selected. Patients received a particulate autogenous bone graft under the same surgical conditions, selecting a site to collect a biopsy and histological study at two months and another at six months postoperatively. Histomorphometry was performed and were used Kolmogorov-Smirnov test, student's t-test and Spearman's correlation coefficient, considering a value of p<0.05. Differences were observed in inflammatory infiltrate and vascularization characteristics; however, the group analyzed at two months presented 38.12% ± 6.64 % of mineralized tissue, whereas the group studied at 6 months presented an average of 38.45 ± 9.27 %. There were no statistical differences between the groups. It is concluded that the bone formation may be similar in intrasinus particulate autogenous bone grafts in evaluations at two or six months; under these conditions, early installation of implants is viable.

  6. Bone Formation in Maxillary Sinus Lift Using Autogenous Bone Graft at 2 and 6 Months

    PubMed Central

    Netto, Henrique Duque; Miranda Chaves, Maria das Graças Alfonso; Aatrstrup, Beatriz; Guerra, Renata; Olate, Sergio

    2016-01-01

    SUMMARY The aim of this study is to compare the bone formation in maxillary sinus lift with an autogenous bone graft in histological evaluation at 2 or 6 months. A comparative study was designed where 10 patients with missing teeth bilaterally in the posterior zone of the maxilla were selected. Patients received a particulate autogenous bone graft under the same surgical conditions, selecting a site to collect a biopsy and histological study at two months and another at six months postoperatively. Histomorphometry was performed and were used Kolmogorov-Smirnov test, student’s t-test and Spearman’s correlation coefficient, considering a value of p<0.05. Differences were observed in inflammatory infiltrate and vascularization characteristics; however, the group analyzed at two months presented 38.12% ± 6.64 % of mineralized tissue, whereas the group studied at 6 months presented an average of 38.45 ± 9.27 %. There were no statistical differences between the groups. It is concluded that the bone formation may be similar in intrasinus particulate autogenous bone grafts in evaluations at two or six months; under these conditions, early installation of implants is viable. PMID:27867255

  7. Multi-protein Delivery by Nanodiamonds Promotes Bone Formation

    PubMed Central

    Moore, L.; Gatica, M.; Kim, H.; Osawa, E.; Ho, D.

    2013-01-01

    Bone morphogenetic proteins (BMPs) are well-studied regulators of cartilage and bone development that have been Food and Drug Administration (FDA)-approved for the promotion of bone formation in certain procedures. BMPs are seeing more use in oral and maxillofacial surgeries because of recent FDA approval of InFUSE® for sinus augmentation and localized alveolar ridge augmentation. However, the utility of BMPs in medical and dental applications is limited by the delivery method. Currently, BMPs are delivered to the surgical site by the implantation of bulky collagen sponges. Here we evaluate the potential of detonation nanodiamonds (NDs) as a delivery vehicle for BMP-2 and basic fibroblast growth factor (bFGF). Nanodiamonds are biocompatible, 4- to 5-nm carbon nanoparticles that have previously been used to deliver a wide variety of molecules, including proteins and peptides. We find that both BMP-2 and bFGF are readily loaded onto NDs by physisorption, forming a stable colloidal solution, and are triggered to release in slightly acidic conditions. Simultaneous delivery of BMP-2 and bFGF by ND induces differentiation and proliferation in osteoblast progenitor cells. Overall, we find that NDs provide an effective injectable alternative for the delivery of BMP-2 and bFGF to promote bone formation. PMID:24045646

  8. Multi-protein delivery by nanodiamonds promotes bone formation.

    PubMed

    Moore, L; Gatica, M; Kim, H; Osawa, E; Ho, D

    2013-11-01

    Bone morphogenetic proteins (BMPs) are well-studied regulators of cartilage and bone development that have been Food and Drug Administration (FDA)-approved for the promotion of bone formation in certain procedures. BMPs are seeing more use in oral and maxillofacial surgeries because of recent FDA approval of InFUSE(®) for sinus augmentation and localized alveolar ridge augmentation. However, the utility of BMPs in medical and dental applications is limited by the delivery method. Currently, BMPs are delivered to the surgical site by the implantation of bulky collagen sponges. Here we evaluate the potential of detonation nanodiamonds (NDs) as a delivery vehicle for BMP-2 and basic fibroblast growth factor (bFGF). Nanodiamonds are biocompatible, 4- to 5-nm carbon nanoparticles that have previously been used to deliver a wide variety of molecules, including proteins and peptides. We find that both BMP-2 and bFGF are readily loaded onto NDs by physisorption, forming a stable colloidal solution, and are triggered to release in slightly acidic conditions. Simultaneous delivery of BMP-2 and bFGF by ND induces differentiation and proliferation in osteoblast progenitor cells. Overall, we find that NDs provide an effective injectable alternative for the delivery of BMP-2 and bFGF to promote bone formation.

  9. Bone development in black ducks as affected by dietary toxaphene

    USGS Publications Warehouse

    Mehrle, P.M.; Finley, M.T.; Ludke, J.L.; Mayer, F.L.; Kaiser, T.E.

    1979-01-01

    Black ducks, Anas rubripes, were exposed to dietary toxaphene concentrations of 0, 10, or 50 μg/g of food for 90 days prior to laying and through the reproductive season. Toxaphene did not affect reproduction or survival, but reduced growth and impaired backbone development in ducklings. Collagen, the organic matrix of bone, was decreased significantly in cervical vertebrae of ducklings fed 50 μg/g, and calcium conentrations increased in vertebrae of ducklings fed 10 or 50 μg/g. The effects of toxaphene were observed only in female ducklings. In contrast to effects on vertebrae, toxaphene exposure did not alter tibia development. Toxaphene residues in carcasses of these ducklings averaged slightly less than the dietary levels.

  10. High-dose therapy improves the bone remodelling compartment canopy coverage and bone formation in multiple myeloma.

    PubMed

    Hinge, Maja; Delaisse, Jean-Marie; Plesner, Torben; Clasen-Linde, Erik; Salomo, Morten; Andersen, Thomas Levin

    2015-11-01

    Bone loss in multiple myeloma (MM) is caused by an uncoupling of bone formation to resorption trigged by malignant plasma cells. Increasing evidence indicates that the bone remodelling compartment (BRC) canopy, which normally covers the remodelling sites, is important for coupled bone remodelling. Loss of this canopy has been associated with bone loss. This study addresses whether the bone remodelling in MM is improved by high-dose therapy. Bone marrow biopsies obtained from 20 MM patients, before and after first-line treatment with high-dose melphalan followed by autologous stem cell transplantation, and from 20 control patients with monoclonal gammopathy of undetermined significance were histomorphometrically investigated. This investigation confirmed that MM patients exhibited uncoupled bone formation to resorption and reduced canopy coverage. More importantly, this study revealed that a good response to anti-myeloma treatment increased the extent of formative bone surfaces with canopy, and reduced the extent of eroded surfaces without canopy, reverting the uncoupled bone remodelling, while improving canopy coverage. The association between improved coupling and the canopy coverage supports the notion that canopies are critical for the coupling of bone formation to resorption. Furthermore, this study supports the observation that systemic bone disease in MM can be reversed in MM patients responding to anti-myeloma treatment.

  11. Profilin1 Regulates Sternum Development and Endochondral Bone Formation

    PubMed Central

    Miyajima, Daisuke; Hayata, Tadayoshi; Suzuki, Takafumi; Hemmi, Hiroaki; Nakamoto, Tetsuya; Notomi, Takuya; Amagasa, Teruo; Böttcher, Ralph T.; Costell, Mercedes; Fässler, Reinhard; Ezura, Yoichi; Noda, Masaki

    2012-01-01

    Bone development is a dynamic process that requires cell motility and morphological adaptation under the control of actin cytoskeleton. This actin cytoskeleton system is regulated by critical modulators including actin-binding proteins. Among them, profilin1 (Pfn1) is a key player to control actin fiber structure, and it is involved in a number of cellular activities such as migration. During the early phase of body development, skeletal stem cells and osteoblastic progenitor cells migrate to form initial rudiments for future skeletons. During this migration, these cells extend their process based on actin cytoskeletal rearrangement to locate themselves in an appropriate location within microenvironment. However, the role of Pfn1 in regulation of mesenchymal progenitor cells (MPCs) during skeletal development is incompletely understood. Here we examined the role of Pfn1 in skeletal development using a genetic ablation of Pfn1 in MPCs by using Prx1-Cre recombinase. We found that Pfn1 deficiency in MPCs caused complete cleft sternum. Notably, Pfn1-deficient mice exhibited an absence of trabecular bone in the marrow space of appendicular long bone. This phenotype is location-specific, as Pfn1 deficiency did not largely affect osteoblasts in cortical bone. Pfn1 deficiency also suppressed longitudinal growth of long bone. In vitro, Pfn1 deficiency induced retardation of osteoblastic cell migration. These observations revealed that Pfn1 is a critical molecule for the skeletal development, and this could be at least in part associated with the retardation of cell migration PMID:22773831

  12. Calcification preceding new bone formation induced by demineralized bone matrix gelatin.

    PubMed

    Yamashita, K; Takagi, T

    1992-03-01

    Demineralized bone matrix gelatin (BMG) was implanted into the skeletal muscle of Sprague-Dawley (S.D.) rats, and histological changes were examined 3, 5, 7, 10 and 15 days later. Before bone formation, a specific calcification process was found in most of the BMG from day 5 and 7 after implantation. The heterotopic calcified sites were not always consistent with the sites of the alkaline phosphatase activity. It was considered that this calcification progresses without any cellular components, and we distinguished this type of calcification as "acellular mineral deposition" from the calcification which occurs in new bone formation. This "acellular mineral deposition" was first observed as small spherical calcified deposits in the BMG on day 7 after implantation; these deposits then gradually grew and fused with each other. Some multinucleated cells appeared near the site of calcification on day 7 after implantation, but osteoblasts or osteoblast-like cells were scarcely observed around the calcified deposits in BMG until day 7. Vascularization was often observed near the "acellular mineral deposition" and the new bone formation. Fourier transform infrared spectroscopy showed that the calcified deposits in BMG were composed of hydroxyapatite, carbonateapatite and other calcium phosphate components, and that the first two components became prominent with time. It is believed that the "acellular mineral deposition" is due to the deposition of calcium and phosphate into the BMG by a process of heterogenic nucleation that does not involve osteoblasts or matrix vesicles. Bone formation induced by the BMG occurred after the "acellular mineral deposition." The experimental calcification shown in this paper seems a useful model for the study of biocalcification.

  13. Bone morphogenetic protein Smads signaling in mesenchymal stem cells affected by osteoinductive calcium phosphate ceramics.

    PubMed

    Tang, Zhurong; Wang, Zhe; Qing, Fangzhu; Ni, Yilu; Fan, Yujiang; Tan, Yanfei; Zhang, Xingdong

    2015-03-01

    Porous calcium phosphate ceramics (CaP ceramics) could induce ectopic bone formation which was regulated by various signal molecules. In this work, bone marrow mesenchymal stem cells (MSCs) were cultured on the surface of osteoinductive hydroxyapatite (HA) and biphasic calcium phosphate (BCP) ceramics in comparison with control (culture plate) for up to 14 days to detect the signal molecules which might be affected by the CaP ceramics. Without adding osteogenic factors, MSCs cultured on HA and BCP both expressed higher Runx2, Osterix, collagen type I, osteopontin, bone sialoprotein, and osteocalcin at various stages compared with control, thus confirmed the osteoblastic differentiation of MSCs. Later study demonstrated the messenger RNA level of bone morphogenetic protein 2 (BMP2) and BMP4 were also significantly enhanced by HA and BCP. Furthermore, Smad1, 4, 5, and Dlx5, the main molecules in the BMP/Smads signaling pathway, were upregulated by HA and BCP. Moreover, the higher expression of Smads and BMP2, 4 in BCP over HA, corresponded to the better performance of BCP in stimulating in vitro osteoblastic differentiation of MSCs. This was in accordance with the better osteoinductivity of BCP over HA in vivo. Altogether, these results implied that the CaP ceramics may initiate the osteoblastic differentiation of MSCs by influencing the expression of molecules in BMP/Smads pathway.

  14. Peptide-induced de novo bone formation after tooth extraction prevents alveolar bone loss in a murine tooth extraction model.

    PubMed

    Arai, Yuki; Aoki, Kazuhiro; Shimizu, Yasuhiro; Tabata, Yasuhiko; Ono, Takashi; Murali, Ramachandran; Mise-Omata, Setsuko; Wakabayashi, Noriyuki

    2016-07-05

    Tooth extraction causes bone resorption of the alveolar bone volume. Although recombinant human bone morphogenetic protein 2 (rhBMP-2) markedly promotes de novo bone formation after tooth extraction, the application of high-dose rhBMP-2 may induce side effects, such as swelling, seroma, and an increased cancer risk. Therefore, reduction of the necessary dose of rhBMP-2 which can still obtain sufficient bone mass is necessary by developing a new osteogenic reagent. Recently, we showed that the systemic administration of OP3-4 peptide, which was originally designed as a bone resorption inhibitor, had osteogenic ability both in vitro and in vivo. This study evaluated the ability of the local application of OP3-4 peptide to promote bone formation in a murine tooth extraction model with a very low-dose of BMP. The mandibular incisor was extracted from 10-week-old C57BL6/J male mice and a gelatin hydrogel containing rhBMP-2 with or without OP3-4 peptide (BMP/OP3-4) was applied to the socket of the incisor. Bone formation inside the socket was examined radiologically and histologically at 21 days after the extraction. The BMP/OP3-4-group showed significant bone formation inside the mandibular extraction socket compared to the gelatin-hydrogel-carrier-control group or rhBMP-2-applied group. The BMP/OP3-4-applied mice showed a lower reduction of alveolar bone and fewer osteoclast numbers, suggesting that the newly formed bone inside the socket may prevent resorption of the cortical bone around the extraction socket. Our data revealed that OP3-4 peptide promotes BMP-mediated bone formation inside the extraction socket of mandibular bone, resulting in preservation from the loss of alveolar bone.

  15. Radiation-blocking shields to localize periarticular radiation precisely for prevention of heterotopic bone formation around uncemented total hip arthroplasties

    SciTech Connect

    Jasty, M.; Schutzer, S.; Tepper, J.; Willett, C.; Stracher, M.A.; Harris, W.H. )

    1990-08-01

    Sixteen patients (18 hips) were treated with localized radiation therapy limited to periarticular regions surrounding the femoral neck by shielding the prosthesis and the adjacent regions to prevent heterotopic bone formation around the uncemented prosthesis. All hips received 1500 rads. Eight of these hips were irradiated after excising severe heterotopic bone, five because they developed extensive heterotopic ossification in the opposite hip, and five others because they were considered to be at high risk for developing heterotopic ossification. Only two of the 18 hips developed a small amount of heterotopic bone after localized periarticular radiation. All wounds healed primarily. No progressive radiolucencies developed at the bone-prosthesis interface. There was only one trochanteric nonunion of six trochanteric osteotomies. Localized periarticular radiation therapy with precision shielding of the prosthetic components and adjacent skeletal structures is an effective means to prevent heterotopic bone formation around cementless total hip arthroplasties. It also has the advantage of not adversely affecting the healing of the trochanteric osteotomy.

  16. A short-term zinc-deficient diet decreases bone formation through down-regulated BMP2 in rat bone.

    PubMed

    Suzuki, Takako; Katsumata, Shin-Ichi; Matsuzaki, Hiroshi; Suzuki, Kazuharu

    2016-07-01

    We investigated the effects of a short-term dietary zinc deficiency on bone metabolism. Zinc deficiency increased the mRNA expression of zinc uptake transporters such as Zip1, Zip13, and Zip14 in bone. However, zinc deficiency might not maintain zinc storage in bone, resulting in a decrease in bone formation through downregulation of the expression levels of osteoblastogenesis-related genes.

  17. Mechanical Vibration Mitigates the Decrease of Bone Quantity and Bone Quality of Leptin Receptor-Deficient Db/Db Mice by Promoting Bone Formation and Inhibiting Bone Resorption.

    PubMed

    Jing, Da; Luo, Erping; Cai, Jing; Tong, Shichao; Zhai, Mingming; Shen, Guanghao; Wang, Xin; Luo, Zhuojing

    2016-09-01

    Leptin, a major hormonal product of adipocytes, is involved in regulating appetite and energy metabolism. Substantial studies have revealed the anabolic actions of leptin on skeletons and bone cells both in vivo and in vitro. Growing evidence has substantiated that leptin receptor-deficient db/db mice exhibit decreased bone mass and impaired bone microstructure despite several conflicting results previously reported. We herein systematically investigated bone microarchitecture, mechanical strength, bone turnover and its potential molecular mechanisms in db/db mice. More importantly, we also explored an effective approach for increasing bone mass in leptin receptor-deficient animals in an easy and noninvasive manner. Our results show that deterioration of trabecular and cortical bone microarchitecture and decreases of skeletal mechanical strength-including maximum load, yield load, stiffness, energy, tissue-level modulus and hardness-in db/db mice were significantly ameliorated by 12-week, whole-body vibration (WBV) with 0.5 g, 45 Hz via micro-computed tomography (μCT), three-point bending, and nanoindentation examinations. Serum biochemical analysis shows that WBV significantly decreased serum tartrate-resistant acid phosphatase 5b (TRACP5b) and CTx-1 levels and also mitigated the reduction of serum osteocalcin (OCN) in db/db mice. Bone histomorphometric analysis confirmed that decreased bone formation-lower mineral apposition rate, bone formation rate, and osteoblast numbers in cancellous bone-in db/db mice were suppressed by WBV. Real-time PCR assays show that WBV mitigated the reductions of tibial alkaline phosphatase (ALP), OCN, Runt-related transcription factor 2 (RUNX2), type I collagen (COL1), BMP2, Wnt3a, Lrp6, and β-catenin mRNA expression, and prevented the increases of tibial sclerostin (SOST), RANK, RANKL, RANL/osteoprotegerin (OPG) gene levels in db/db mice. Our results show that WBV promoted bone quantity and quality in db/db mice with obvious

  18. Discoidin Receptor 2 Controls Bone Formation and Marrow Adipogenesis.

    PubMed

    Ge, Chunxi; Wang, Zhengyan; Zhao, Guisheng; Li, Binbin; Liao, Jinhui; Sun, Hanshi; Franceschi, Renny T

    2016-12-01

    Cell-extracellular matrix (ECM) interactions play major roles in controlling progenitor cell fate and differentiation. The receptor tyrosine kinase, discoidin domain receptor 2 (DDR2), is an important mediator of interactions between cells and fibrillar collagens. DDR2 signals through both ERK1/2 and p38 MAP kinase, which stimulate osteoblast differentiation and bone formation. Here we show that DDR2 is critical for skeletal development and differentiation of marrow progenitor cells to osteoblasts while suppressing marrow adipogenesis. Smallie mice (Ddr2(slie/slie) ), which contain a nonfunctional Ddr2 allele, have multiple skeletal defects. A progressive decrease in tibial trabecular bone volume/total volume (BV/TV) was observed when wild-type (WT), Ddr2(wt/slie) , and Ddr2(slie/slie) mice were compared. These changes were associated with reduced trabecular number (Tb.N) and trabecular thickness (Tb.Th) and increased trabecular spacing (Tb.Sp) in both males and females, but reduced cortical thickness only in Ddr2(slie/slie) females. Bone changes were attributed to decreased bone formation rather than increased osteoclast activity. Significantly, marrow fat and adipocyte-specific mRNA expression were significantly elevated in Ddr2(slie/slie) animals. Additional skeletal defects include widened calvarial sutures and reduced vertebral trabecular bone. To examine the role of DDR2 signaling in cell differentiation, bone marrow stromal cells (BMSCs) were grown under osteogenic and adipogenic conditions. Ddr2(slie/slie) cells exhibited defective osteoblast differentiation and accelerated adipogenesis. Changes in differentiation were related to activity of runt-related transcription factor 2 (RUNX2) and PPARγ, transcription factors that are both controlled by MAPK-dependent phosphorylation. Specifically, the defective osteoblast differentiation in calvarial cells from Ddr2(slie/slie) mice was associated with reduced ERK/MAP kinase and RUNX2-S319 phosphorylation and could

  19. Hedgehog signaling mediates woven bone formation and vascularization during stress fracture healing

    PubMed Central

    Kazmers, Nikolas H.; McKenzie, Jennifer A.; Shen, Tony S.; Long, Fanxin; Silva, Matthew J.

    2015-01-01

    Hedgehog (Hh) signaling is critical in developmental osteogenesis, and recent studies suggest it may also play a role in regulating osteogenic gene expression in the post-natal setting. However, there is a void of studies directly assessing the effect of Hh inhibition on post-natal osteogenesis. This study utilized a cyclic loading-induced ulnar stress fracture model to evaluate the hypothesis that Hh signaling contributes to osteogenesis and angiogenesis during stress fracture healing. Immediately prior to loading, adult rats were given GDC-0449 (Vismodegib - a selective Hh pathway inhibitor; 50mg/kg orally twice daily), or vehicle. Hh signaling was upregulated in response to stress fracture at 3d (Ptch1, Gli1 expression), and was markedly inhibited by GDC-0449 at 1d and 3d in the loaded and non-loaded ulnae. GDC-0449 did not affect Hh ligand expression (Shh, Ihh, Dhh) at 1d, but decreased Shh expression by 37% at 3d. GDC-0449 decreased woven bone volume (−37%) and mineral density (−17%) at 7d. Dynamic histomorphometry revealed that the 7d callus was composed predominantly of woven bone in both groups. The observed reduction in woven bone occurred concomitantly with decreased expression of Alpl and Ibsp, but was not associated with differences in early cellular proliferation (as determined by callus PCNA staining at 3d), osteoblastic differentiation (Osx expression at 1d and 3d), chondrogenic gene expression (Acan, Sox9, and Col2α1 expression at 1d and 3d), or bone resorption metrics (callus TRAP staining at 3d, Rankl and Opg expression at 1d and 3d). To evaluate angiogenesis, vWF immunohistochemistry showed that GDC-0449 reduced fracture callus blood vessel density by 55% at 3d, which was associated with increased Hif1α gene expression (+30%). Dynamic histomorphometric analysis demonstrated that GDC-0449 also inhibited lamellar bone formation. Lamellar bone analysis of the loaded limb (directly adjacent to the woven bone callus) showed that GDC-0449

  20. Hedgehog signaling mediates woven bone formation and vascularization during stress fracture healing.

    PubMed

    Kazmers, Nikolas H; McKenzie, Jennifer A; Shen, Tony S; Long, Fanxin; Silva, Matthew J

    2015-12-01

    Hedgehog (Hh) signaling is critical in developmental osteogenesis, and recent studies suggest it may also play a role in regulating osteogenic gene expression in the post-natal setting. However, there is a void of studies directly assessing the effect of Hh inhibition on post-natal osteogenesis. This study utilized a cyclic loading-induced ulnar stress fracture model to evaluate the hypothesis that Hh signaling contributes to osteogenesis and angiogenesis during stress fracture healing. Immediately prior to loading, adult rats were given GDC-0449 (Vismodegib - a selective Hh pathway inhibitor; 50mg/kg orally twice daily), or vehicle. Hh signaling was upregulated in response to stress fracture at 3 days (Ptch1, Gli1 expression), and was markedly inhibited by GDC-0449 at 1 day and 3 days in the loaded and non-loaded ulnae. GDC-0449 did not affect Hh ligand expression (Shh, Ihh, Dhh) at 1 day, but decreased Shh expression by 37% at 3 days. GDC-0449 decreased woven bone volume (-37%) and mineral density (-17%) at 7 days. Dynamic histomorphometry revealed that the 7 day callus was composed predominantly of woven bone in both groups. The observed reduction in woven bone occurred concomitantly with decreased expression of Alpl and Ibsp, but was not associated with differences in early cellular proliferation (as determined by callus PCNA staining at 3 days), osteoblastic differentiation (Osx expression at 1 day and 3 days), chondrogenic gene expression (Acan, Sox9, and Col2α1 expression at 1 day and 3 days), or bone resorption metrics (callus TRAP staining at 3 days, Rankl and Opg expression at 1 day and 3 days). To evaluate angiogenesis, vWF immunohistochemistry showed that GDC-0449 reduced fracture callus blood vessel density by 55% at 3 days, which was associated with increased Hif1α gene expression (+30%). Dynamic histomorphometric analysis demonstrated that GDC-0449 also inhibited lamellar bone formation. Lamellar bone analysis of the loaded limb (directly adjacent

  1. How the cosmological constant affects gravastar formation

    SciTech Connect

    Chan, R.; Silva, M.F.A. da; Rocha, P. E-mail: mfasnic@gmail.com

    2009-12-01

    Here we generalized a previous model of gravastar consisted of an internal de Sitter spacetime, a dynamical infinitely thin shell with an equation of state, but now we consider an external de Sitter-Schwarzschild spacetime. We have shown explicitly that the final output can be a black hole, a ''bounded excursion'' stable gravastar, a stable gravastar, or a de Sitter spacetime, depending on the total mass of the system, the cosmological constants, the equation of state of the thin shell and the initial position of the dynamical shell. We have found that the exterior cosmological constant imposes a limit to the gravastar formation, i.e., the exterior cosmological constant must be smaller than the interior cosmological constant. Besides, we have also shown that, in the particular case where the Schwarzschild mass vanishes, no stable gravastar can be formed, but we still have formation of black hole.

  2. 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

  3. Deficiency of ATP6V1H Causes Bone Loss by Inhibiting Bone Resorption and Bone Formation through the TGF-β1 Pathway

    PubMed Central

    Duan, Xiaohong; Liu, Jin; Zheng, Xueni; Wang, Zhe; Zhang, Yanli; Hao, Ying; Yang, Tielin; Deng, Hongwen

    2016-01-01

    Vacuolar-type H +-ATPase (V-ATPase) is a highly conserved, ancient enzyme that couples the energy of ATP hydrolysis to proton transport across vesicular and plasma membranes of eukaryotic cells. Previously reported mutations of various V-ATPase subunits are associated with increased bone density. We now show that haploinsufficiency for the H subunit of the V1 domain (ATP6V1H) is associated with osteoporosis in humans and mice. A genome-wide SNP array analysis of 1625 Han Chinese found that 4 of 15 tag SNPs (26.7%) within ATP6V1H were significantly associated with low spine bone mineral density. Atp6v1h+/- knockout mice generated by the CRISPR/Cas9 technique had decreased bone remodeling and a net bone matrix loss. Atp6v1h+/- osteoclasts showed impaired bone formation and increased bone resorption. The increased intracellular pH of Atp6v1h+/- osteoclasts downregulated TGF-β1 activation, thereby reducing induction of osteoblast formation but the bone mineralization was not altered. However, bone formation was reduced more than bone resorption. Our data provide evidence that partial loss of ATP6V1H function results in osteoporosis/osteopenia. We propose that defective osteoclast formation triggers impaired bone formation by altering bone remodeling. In the future, ATP6V1H might, therefore, serve as a target for the therapy of osteoporosis. PMID:27924156

  4. Effect of calcium sulfate-chitosan composite: pellet on bone formation in bone defect.

    PubMed

    Cho, Byung Chae; Kim, Tae Gyu; Yang, Jung Duk; Chung, Ho Yun; Park, Jae Woo; Kwon, Ick Chan; Roh, Kyung Ho; Chung, Hye Sun; Lee, Dong Sin; Park, Nang Un; Kim, In San

    2005-03-01

    The purpose of this experiment was to study the effects of chitosan, calcium sulfate, and calcium sulfate-chitosan composite pellet on the osteogenesis of defective tibia in rabbits. Eighty New Zealand white rabbits, each weighing approximately 3 to 3.5 kg, were used for this study. A 1-cm ostectomy was made on the middle of the tibia of each rabbit with the periosteum preserved. Nothing was implanted in the control group (group 1), and five chitosan pellets (60 mg/pellet) were implanted in group 1, three OsteoSet pellets (100 mg/pellet) in group 3, and four calcium sulfate-chitosan composite pellets (1 pellet, 80 mg; calcium sulfate 40 mg/pellet, chitosan 40 mg/pellet) in group 4. For each group, a radiographic study, bone mineral density test, three-point bending test, and histologic examination were performed in the second, fourth, and sixth weeks. In the radiologic study, in group 1, cortical bone was not formed even at 6 weeks. In group 2, it was observed at 6 weeks. In groups 3 and 4, cortical bone was partially seen around the fourth week. At 6 weeks, it was clearly observed on both sides, and the projection of the marrow cavity became distinctive, so bone consolidation was considered to be much progressed. The bone mineral density test and three-point bending test results appeared to be highly similar in groups 3 and 4 and in groups 2 and 1. Particularly at 6 weeks, the measures for groups 3 and 4 were statistically significant compared with those for groups 1 and 2 (P < 0.05). In histologic examination, new bone formation began to be seen at 2 weeks in all groups, but it was more active and faster in groups 3 and 4. At 6 weeks, fibrous connective tissue still remained at the center in groups 1 and 2; however, the fibrous connective tissue at the center was replaced with callus, the bony bridge was obvious, and lamellation of callus was observed more in groups 3 and 4. The results indicate that chitosan pellets, OsteoSet, and chitosan-calcium sulfate

  5. Bisphosphonates do not inhibit periosteal bone formation in estrogen deficient animals and allow enhanced bone modeling in response to mechanical loading.

    PubMed

    Feher, Anthony; Koivunemi, Andrew; Koivunemi, Mark; Fuchs, Robyn K; Burr, David B; Phipps, Roger J; Reinwald, Susan; Allen, Matthew R

    2010-01-01

    The suppressive effects of bisphosphonates (BPs) on bone remodeling are clear yet there is conflicting data concerning the effects of BPs on modeling (specifically formation modeling on the periosteal surface). The normal periosteal expansion that occurs during aging has significant benefits to maintaining/improving the bones' mechanical properties and thus it is important to understand whether BPs affect this bone surface. Therefore, the purpose of this study was to determine the effects of BPs on periosteal bone formation modeling induced by ovariectomy (OVX) and mechanical loading. Six-month-old Sprague-Dawley OVX rats (n=60; 12/group) were administered vehicle, risedronate, alendronate, or zoledronate at doses used clinically for treatment of post-menopausal osteoporosis. Three weeks after initiating BP treatment, all animals underwent in vivo ulnar loading of the right limb every other day for 1 week (3 total sessions). Periosteal surface mineral apposition rate, mineralizing surface, and bone formation rate were determined at the mid-diaphysis of both loaded (right) and non-loaded (left) ulnae. There was no significant effect of any of the BPs on periosteal bone formation parameters compared to VEH-treated animals in the non-loaded limb, suggesting that BP treatment does not compromise the normal periosteal expansion associated with estrogen loss. Mechanical loading significantly increased BFR in the loaded limb compared to the non-loaded limb in all BP-treated groups, with no difference in the magnitude of this effect among the various BPs. Collectively, these data show that BP treatment, at doses comparable to those used for treatment of post-menopausal osteoporosis, (1) does not alter the periosteal formation activity that occurs in the absence of estrogen and (2) allows normal stimulation of periosteal bone formation in response to the anabolic stimulation of mechanical loading.

  6. Identification of Mechanosensitive Genes during Embryonic Bone Formation

    PubMed Central

    Nowlan, Niamh C.; Prendergast, Patrick J.; Murphy, Paula

    2008-01-01

    Although it is known that mechanical forces are needed for normal bone development, the current understanding of how biophysical stimuli are interpreted by and integrated with genetic regulatory mechanisms is limited. Mechanical forces are thought to be mediated in cells by “mechanosensitive” genes, but it is a challenge to demonstrate that the genetic regulation of the biological system is dependant on particular mechanical forces in vivo. We propose a new means of selecting candidate mechanosensitive genes by comparing in vivo gene expression patterns with patterns of biophysical stimuli, computed using finite element analysis. In this study, finite element analyses of the avian embryonic limb were performed using anatomically realistic rudiment and muscle morphologies, and patterns of biophysical stimuli were compared with the expression patterns of four candidate mechanosensitive genes integral to bone development. The expression patterns of two genes, Collagen X (ColX) and Indian hedgehog (Ihh), were shown to colocalise with biophysical stimuli induced by embryonic muscle contractions, identifying them as potentially being involved in the mechanoregulation of bone formation. An altered mechanical environment was induced in the embryonic chick, where a neuromuscular blocking agent was administered in ovo to modify skeletal muscle contractions. Finite element analyses predicted dramatic changes in levels and patterns of biophysical stimuli, and a number of immobilised specimens exhibited differences in ColX and Ihh expression. The results obtained indicate that computationally derived patterns of biophysical stimuli can be used to inform a directed search for genes that may play a mechanoregulatory role in particular in vivo events or processes. Furthermore, the experimental data demonstrate that ColX and Ihh are involved in mechanoregulatory pathways and may be key mediators in translating information from the mechanical environment to the molecular

  7. Regulation of Bone Formation During Disuse by miRNA

    NASA Technical Reports Server (NTRS)

    Thomas, Nicholas; Choi, Catherine Y.; Alwood, Joshua S.

    2016-01-01

    Astronauts lose bone structure during long-duration spaceflight. These changes are due, in part, to insufficient bone formation by the osteoblast cells. Little is known about the role that small (approximately 22 nucleotide), non-coding micro-RNAs (miRNAs) play in the osteoblast response to microgravity. We hypothesize that osteoblast-lineage cells alter their miRNA status during microgravity exposure, contributing to impaired bone formation during weightlessness. To simulate weightlessness, female mice (C57BL/6, Charles River, 10 weeks of age, n = 6) were hindlimb unloaded for 12 days. Age-matched and normally ambulating mice served as controls (n=6). To assess the expression of miRNAs in skeletal tissue, the right and left tibia of the mice were collected ex vivo and cleaned of soft-tissue and marrow. Total RNA was collected from tibial bone and relative abundance was measured for miRNAs of interest using quantitative real time PCR array looking at 372 unique and well-characterized mature miRNAs using the delta-delta Ct method. Transcripts of interest were normalized to an average of 6 reference RNAs. Preliminary results show that hindlimb unloading decreased the expression of 14 miRNAs to less than 1.4-2.9X control levels and increased the expression of 5 miRNAs relative to the control mice greater than 1-2-1.5X (p less than 0.05, respectively). Using the miRSystem we assessed overlapping target genes predicted to be regulated by multiple members of the 19 differentially expressed miRNAs as well as in silico predicted targets of our individual miRNAs. Our miRSystem results indicated that a number of our differentially expressed miRNAs were regulators of genes related to the Wnt-Beta Catenin pathway-a known regulator of bone health-and, interestingly, the estrogen-mediated cell-cycle regulation pathway, which may indicate that simulated weightlessness induced systemic hormonal changes that contributed to bone loss. We plan to follow up these findings by measuring

  8. Heparin affects human bone marrow stromal cell fate: Promoting osteogenic and reducing adipogenic differentiation and conversion.

    PubMed

    Simann, Meike; Schneider, Verena; Le Blanc, Solange; Dotterweich, Julia; Zehe, Viola; Krug, Melanie; Jakob, Franz; Schilling, Tatjana; Schütze, Norbert

    2015-09-01

    Heparins are broadly used for the prevention and treatment of thrombosis and embolism. Yet, osteoporosis is considered to be a severe side effect in up to one third of all patients on long-term treatment. However, the mechanisms underlying this clinical problem are only partially understood. To investigate if heparin affects differentiation of skeletal precursors, we examined the effects of heparin on the osteogenic and adipogenic lineage commitment and differentiation of primary human bone marrow stromal cells (hBMSCs). Due to the known inverse relationship between adipogenesis and osteogenesis and the capacity of pre-differentiated cells to convert into the respective other lineage, we also determined heparin effects on osteogenic conversion and adipogenic differentiation/conversion. Interestingly, heparin did not only significantly increase mRNA expression and enzyme activity of the osteogenic marker alkaline phosphatase (ALP), but it also promoted mineralization during osteogenic differentiation and conversion. Furthermore, the mRNA expression of the osteogenic marker bone morphogenic protein 4 (BMP4) was enhanced. In addition, heparin administration partly prevented adipogenic differentiation and conversion demonstrated by reduced lipid droplet formation along with a decreased expression of adipogenic markers. Moreover, luciferase reporter assays, inhibitor experiments and gene expression analyses revealed that heparin had putative permissive effects on osteogenic signaling via the BMP pathway and reduced the mRNA expression of the Wnt pathway inhibitors dickkopf 1 (DKK1) and sclerostin (SOST). Taken together, our data show a rather supportive than inhibitory effect of heparin on osteogenic hBMSC differentiation and conversion in vitro. Further studies will have to investigate the net effects of heparin administration on bone formation versus bone resorption in vivo to unravel the molecular mechanisms of heparin-associated osteoporosis and reconcile

  9. Trauma induced heterotopic bone formation and the role of the immune system: A Review

    PubMed Central

    Kraft, Casey T.; Agarwal, Shailesh; Ranganathan, Kavitha; Wong, Victor W.; Loder, Shawn; Li, John; Delano, Matthew J.; Levi, Benjamin

    2015-01-01

    Extremity trauma, spinal cord injuries, head injuries and burn injuries place patients at high risk of pathologic extraskeletal bone formation. This heterotopic bone causes severe pain, deformities and joint contractures. The immune system has been increasingly implicated in this debilitating condition. This review summarizes the various roles immune cells and inflammation play in the formation of ectopic bone, and highlights potential areas of future investigation and treatment. Cell types in both the innate and adaptive immune system such as neutrophils, macrophages, mast cells, B cells and T cells have all been implicated as having a role in ectopic bone formation through various mechanisms. Many of these cell types are promising areas of therapeutic investigation for potential treatment. The immune system has also been known to also influence osteoclastogenesis, which is heavily involved in ectopic bone formation. Chronic inflammation is also known to have an inhibitory role in the formation of ectopic bone, whereas acute inflammation is necessary for ectopic bone formation. PMID:26491794

  10. Radiation-induced sarcomas of bone: factors that affect outcome.

    PubMed

    Kalra, S; Grimer, R J; Spooner, D; Carter, S R; Tillman, R M; Abudu, A

    2007-06-01

    We identified 42 patients who presented to our unit over a 27-year period with a secondary radiation-induced sarcoma of bone. We reviewed patient, tumour and treatment factors to identify those that affected outcome. The mean age of the patients at presentation was 45.6 years (10 to 84) and the mean latent interval between radiotherapy and diagnosis of the sarcoma was 17 years (4 to 50). The median dose of radiotherapy given was estimated at 50 Gy (mean 49; 20 to 66). There was no correlation between radiation dose and the time to development of a sarcoma. The pelvis was the most commonly affected site (14 patients (33%)). Breast cancer was the most common primary tumour (eight patients; 19%). Metastases were present at diagnosis of the sarcoma in nine patients (21.4%). Osteosarcoma was the most common diagnosis and occurred in 30 cases (71.4%). Treatment was by surgery and chemotherapy when indicated: 30 patients (71.4%) were treated with the intention to cure. The survival rate was 41% at five years for those treated with the intention to cure but in those treated palliatively the mean survival was only 8.8 months (2 to 22), and all had died by two years. The only factor found to be significant for survival was the ability to completely resect the tumour. Limb sarcomas had a better prognosis (66% survival at five years) than central ones (12% survival at five years) (p = 0.009). Radiation-induced sarcoma is a rare complication of radiotherapy. Both surgical and oncological treatment is likely to be compromised by the treatment received previously by the patient.

  11. Radiological study of two disseminated maligant non-Hodgkin lymphomas affecting only the bones in children

    SciTech Connect

    Vanel, D; Rebibo, G.; Tamman, S.; Bayle, C.; Hartmann, O.

    1982-12-01

    Malignant non-Hodgkin lymphomas are a neoplastic proliferation of lymphoid cells whose clinical manifestations are extremely variable. All tissues can be affected. There may be localization in lymphoid organs (Waldeyer's ring, spleen, digestive tract), other localizations (lungs, pleura, liver, bone marrow, central nervous system) and unusual localizations. Although bone marrow is often affected, bone involvement is very rare in the early stages of the disease. This report concerns the radiological study of two disseminated malignant non-Hodgkin lymphomas affecting only the bone in children.

  12. The role of adaptive bone formation in the etiology of stress fracture.

    PubMed

    Hughes, Julie M; Popp, Kristin L; Yanovich, Ran; Bouxsein, Mary L; Matheny, Ronald W

    2016-08-05

    Stress fractures are common injuries with load-bearing activities. Stress fractures have been reported in the scientific literature for over a century; however, the etiology continues to be investigated with important distinctions made between the contributions of the tissue-level processes of bone remodeling and modeling. In response to novel repetitive loading, increased bone remodeling may serve to replace fatigue-damaged bone while at the same time creating temporary porosity. Much attention has been given to the role of remodeling in the etiology of stress fracture; however, the role of bone modeling has received less attention. Modest increases in modeling, via bone formation on the periosteal surface of long bones in response to mechanical loading, greatly increases the fatigue resistance of bone. Thus, enhancing this adaptive bone formation is a promising target for stress fracture prevention, and a focus on adaptive bone formation may reveal novel risk factors for stress fracture.

  13. Quick and inexpensive paraffin-embedding method for dynamic bone formation analyses

    PubMed Central

    Porter, Amy; Irwin, Regina; Miller, Josselyn; Horan, Daniel J.; Robling, Alexander G.; McCabe, Laura R.

    2017-01-01

    We have developed a straightforward method that uses paraffin-embedded bone for undemineralized thin sectioning, which is amenable to subsequent dynamic bone formation measurements. Bone has stiffer material properties than paraffin, and therefore has hereforto usually been embedded in plastic blocks, cured and sectioned with a tungsten carbide knife to obtain mineralized bone sections for dynamic bone formation measures. This process is expensive and requires special equipment, experienced personnel, and time for the plastic to penetrate the bone and cure. Our method utilizes a novel way to prepare mineralized bone that increases its compliance so that it can be embedded and easily section in paraffin blocks. The approach is simple, quick, and costs less than 10% of the price for plastic embedded bone sections. While not effective for static bone measures, this method allows dynamic bone analyses to be readily performed in laboratories worldwide which might not otherwise have access to traditional (plastic) equipment and expertise. PMID:28198415

  14. The effect of hydroxyapatite nanocrystals on early bone formation surrounding dental implants.

    PubMed

    Svanborg, L M; Hoffman, M; Andersson, M; Currie, F; Kjellin, P; Wennerberg, A

    2011-03-01

    The knowledge of how nanostructures might affect early bone healing and osseointegration is limited. The aim of this study was to investigate if nanometer thick coatings of hydroxyapatite nanocrystals applied on a moderately rough surface might enhance early bone healing on screw-shaped dental implants and to evaluate if the thickness of the coat influences healing. Sandblasted and acid etched titanium implants coated with two different thicknesses of hydroxyapatite (test implants) and sandblasted and acid etched titanium implants (control implants), were inserted in rabbit tibia. After a healing time of 2, 4 and 9 weeks, a removal torque analysis and a histological evaluation were performed. The results from the removal torque analysis showed a tendency for higher values for the double coated hydroxyapatite after 4 weeks and for both the coated surfaces after 9 weeks of healing. The histological evaluations indicated slightly more new bone formation with the coated implants compared with the control; the differences did not reach statistical significance. The present study could not support the importance of nanometer thick coatings of hydroxyapatite nanocrystals in early bone healing, at least not when applied on a blasted and etched surface and placed in a cortical bone.

  15. Bone formation in algae-derived and synthetic calcium phosphates with or without poloxamer.

    PubMed

    Zhou, Aileen Jing-Jing; Clokie, Cameron Malcolm Lang; Peel, Sean Alexander Fitzgerald

    2013-03-01

    Calcium phosphate ceramics such as hydroxyapatite (HA) and biphasic calcium phosphates are used clinically to repair bone defects. These calcium phosphate ceramics can differ by composition, structure, and rate of degradation. This study compared 3 calcium phosphate ceramics, 2 of which have similar structure but different composition: 100% HA (algae derived) and HA/β-tricalcium phosphate (β-TCP) 20/80 (algae derived), and 2 with different structure but similar composition: HA/β-TCP 20/80 (algae derived) and HA/β-TCP 15/85 (synthetic). Calcium phosphate ceramics can be difficult to handle and contour during the surgeries. To improve handling, Poloxamer 407 (P407) was added to the 3 ceramics, and its effect on bone healing was also assessed. Bilateral calvarial defects created in the parietal bones of New Zealand white rabbits were left unfilled or were filled with autograft or one of the ceramics, with and without P407. Six weeks after operation, healing was evaluated qualitatively by histology and quantitatively by micro-computed tomography analysis and histomorphometry. All 3 calcium phosphate ceramics demonstrated osteoconductivity and performed similarly in supporting new bone formation, suggesting that the differences in their composition, structure, or degradation did not significantly affect their ability to promote bone healing in this application. Incorporating P407 did not impede osteoconductivity as HA and biphasic calcium phosphate combined with P407 performed similarly as when used alone for craniofacial defect repair.

  16. Mice deficient in 11beta-hydroxysteroid dehydrogenase type 1 lack bone marrow adipocytes, but maintain normal bone formation.

    PubMed

    Justesen, Jeannette; Mosekilde, Lis; Holmes, Megan; Stenderup, Karin; Gasser, Jürg; Mullins, John J; Seckl, Jonathan R; Kassem, Moustapha

    2004-04-01

    Glucocorticoids (GCs) exert potent, but poorly characterized, effects on the skeleton. The cellular activity of GCs is regulated at a prereceptor level by 11beta-hydroxysteroid dehydrogenases (11betaHSDs). The type 1 isoform, which predominates in bone, functions as a reductase in intact cells and regenerates active cortisol (corticosterone) from circulating inert 11-keto forms. The aim of the present study was to investigate the role of this intracrine activation of GCs on normal bone physiology in vivo using mice deficient in 11betaHSD1 (HSD1(-/-)). The HSD1(-/-) mice exhibited no significant changes in cortical or trabecular bone mass compared with wild-type (Wt) mice. Aged HSD1(-/-) mice showed age-related bone loss similar to that observed in Wt mice. Histomorphometric analysis showed similar bone formation and bone resorption parameters in HSD1(-/-) and Wt mice. However, examination of bone marrow composition revealed a total absence of marrow adipocytes in HSD1(-/-) mice. Cells from Wt and HSD1(-/-) mice exhibited similar growth rates as well as similar levels of production of osteoblastic markers. The adipocyte-forming capacity of in vitro cultured bone marrow stromal cells and trabecular osteoblasts was similar in HSD1(-/-) and Wt mice. In conclusion, our results suggest that 11betaHSD1 amplification of intracellular GC actions in mice may be required for bone marrow adipocyte formation, but not for bone formation. The clinical relevance of this observation remains to be determined.

  17. Vaccination with DKK1-derived peptides promotes bone formation and bone mass in an aged mouse osteoporosis model.

    PubMed

    Wu, Qiong; Li, Rui-Shu; Zhao, Yue; Wang, Zhi-Xia; Tang, Yan-Chun; Zhang, Jing; Liu, Jian-Ning; Tan, Xiang-Yang

    2014-08-01

    The investigation of agents for the treatment of osteoporosis has been a long-standing effort. The Wnt pathway plays an important role in bone formation and regeneration, and expression of Wnt pathway inhibitors, Dickkopf-1 (DKK1), appears to be associated with changes in bone mass. Inactivation of DKK1 leads to substantially increased bone mass in genetically manipulated animals. DKK1-derived peptides (DDPs) were added to BMP2-stimulated MC3T3-E1 preosteoblastic cells in vitro to evaluate inhibitory activity of DDPs in MC3T3-E1 cell differentiation. Study was extended in vivo on old female mice to show whether or not inhibition of endogenous DKK1 biological activity using DDPs vaccination approach leads to increase of bone formation, bone density, and improvement of bone microstructure. We reported that synthetic DDPs were able to reduce alkaline phosphatase activity, prevent mineralization and inhibit the differentiation of MC3T3-E1 cells in vitro. Furthermore, vaccination with these DDPs in aged female mice 4 times for a total period of 22 weeks promoted bone mass and bone microstructure. 3D microCT and histomorphometric analysis showed that there were significant increase in bone mineral densities, improvement of bone microstructure and promotion of bone formation in the vaccinated mice, especially in the mice vaccinated with DDP-A and DDP-C. Histological and scanning electron microscopy image analysis also indicated that vaccination increased trabecular bone mass and significantly decreased fragmentation of bone fibers. Taken together, these preclinical results suggest that vaccination with DDPs represents a promising new therapeutic approach for the treatment of bone-related disorders, such as osteoporosis.

  18. Treatment with a sclerostin antibody increases cancellous bone formation and bone mass regardless of marrow composition in adult female rats.

    PubMed

    Tian, XiaoYan; Setterberg, Rebecca B; Li, Xiaodong; Paszty, Chris; Ke, Hua Zhu; Jee, Webster S S

    2010-09-01

    The current report describes the skeletal effects of a sclerostin monoclonal antibody (Scl-AbIII) treatment at a yellow (fatty) marrow skeletal site in adult female rats. Ten-month-old female Sprague-Dawley rats were treated with vehicle or Scl-AbIII at 5 or 25 mg/kg, twice per week by s.c. injection for 4 weeks. Trabecular bone from a yellow (fatty) marrow site, the 5th caudal vertebral body (CVB), was processed undecalcified for quantitative bone histomorphometric analysis. Compared to vehicle controls, Scl-AbIII at both doses significantly increased bone formation parameters and trabecular bone volume and thickness and decreased bone resorption parameter in the trabecular bone of the CVB. As a reference, we also found that the Scl-AbIII at both doses significantly decreased bone resorption and increased bone formation and bone volume in a red (hematopoietic) marrow site, the 4th lumber vertebral body (LVB). It appears that the percentage of increase in trabecular bone volume induced by Scl-AbIII treatment was slightly larger in the LVB than in the CVB. In summary, these preclinical findings show that antibody-mediated sclerostin inhibition has significant bone anabolic effects at both red and yellow marrow skeletal sites.

  19. Does Orthodontic Treatment Affect the Alveolar Bone Density?

    PubMed Central

    Yu, Jian-Hong; Huang, Heng-Li; Liu, Chien-Feng; Wu, Jay; Li, Yu-Fen; Tsai, Ming-Tzu; Hsu, Jui-Ting

    2016-01-01

    Abstract Few studies involving human participants have been conducted to investigate the effect of orthodontic treatment on alveolar bone density around the teeth. Our previous study revealed that patients who received 6 months of active orthodontic treatment exhibited an ∼24% decrease in alveolar bone density around the teeth. However, after an extensive retention period following orthodontic treatment, whether the bone density around the teeth can recover to its original state from before the treatment remains unclear, thus warranting further investigation. The purpose of this study was to assess the bone density changes around the teeth before, during, and after orthodontic treatment. Dental cone-beam computed tomography (CBCT) was used to measure the changes in bone density around 6 teeth in the anterior maxilla (maxilla central incisors, lateral incisors, and canines) of 8 patients before and after orthodontic treatment. Each patient underwent 3 dental CBCT scans: before treatment (T0); at the end of 7 months of active orthodontic treatment (T1); after several months (20–22 months) of retention (T2). The Friedman test was applied to evaluate the changes in the alveolar bone density around the teeth according to the 3 dental CBCT scans. From T0 to T1, a significant reduction in bone density was observed around the teeth (23.36 ± 10.33%); by contrast, a significant increase was observed from T1 to T2 (31.81 ± 23.80%). From the perspective of the overall orthodontic treatment, comparing the T0 and T2 scans revealed that the bone density around the teeth was relatively constant (a reduction of only 0.75 ± 19.85%). The results of the statistical test also confirmed that the difference in bone density between T0 and T2 was nonsignificant. During orthodontic tooth movement, the alveolar bone density around the teeth was reduced. However, after a period of bone recovery, the reduced bone density recovered to its previous state from before the

  20. Does Orthodontic Treatment Affect the Alveolar Bone Density?

    PubMed

    Yu, Jian-Hong; Huang, Heng-Li; Liu, Chien-Feng; Wu, Jay; Li, Yu-Fen; Tsai, Ming-Tzu; Hsu, Jui-Ting

    2016-03-01

    Few studies involving human participants have been conducted to investigate the effect of orthodontic treatment on alveolar bone density around the teeth. Our previous study revealed that patients who received 6 months of active orthodontic treatment exhibited an ∼24% decrease in alveolar bone density around the teeth. However, after an extensive retention period following orthodontic treatment, whether the bone density around the teeth can recover to its original state from before the treatment remains unclear, thus warranting further investigation.The purpose of this study was to assess the bone density changes around the teeth before, during, and after orthodontic treatment.Dental cone-beam computed tomography (CBCT) was used to measure the changes in bone density around 6 teeth in the anterior maxilla (maxilla central incisors, lateral incisors, and canines) of 8 patients before and after orthodontic treatment. Each patient underwent 3 dental CBCT scans: before treatment (T0); at the end of 7 months of active orthodontic treatment (T1); after several months (20-22 months) of retention (T2). The Friedman test was applied to evaluate the changes in the alveolar bone density around the teeth according to the 3 dental CBCT scans.From T0 to T1, a significant reduction in bone density was observed around the teeth (23.36 ± 10.33%); by contrast, a significant increase was observed from T1 to T2 (31.81 ± 23.80%). From the perspective of the overall orthodontic treatment, comparing the T0 and T2 scans revealed that the bone density around the teeth was relatively constant (a reduction of only 0.75 ± 19.85%). The results of the statistical test also confirmed that the difference in bone density between T0 and T2 was nonsignificant.During orthodontic tooth movement, the alveolar bone density around the teeth was reduced. However, after a period of bone recovery, the reduced bone density recovered to its previous state from before the orthodontic treatment

  1. Bone formation is not impaired by hibernation (disuse) in black bears Ursus americanus

    USGS Publications Warehouse

    Donahue, S.W.; Vaughan, M.R.; Demers, L.M.; Donahue, H.J.

    2003-01-01

    Disuse by bed rest, limb immobilization or space flight causes rapid bone loss by arresting bone formation and accelerating bone resorption. This net bone loss increases the risk of fracture upon remobilization. Bone loss also occurs in hibernating ground squirrels, golden hamsters, and little brown bats by arresting bone formation and accelerating bone resorption. There is some histological evidence to suggest that black bears Ursus americanus do not lose bone mass during hibernation (i.e. disuse). There is also evidence suggesting that muscle mass and strength are preserved in black bears during hibernation. The question of whether bears can prevent bone loss during hibernation has not been conclusively answered. The goal of the current study was to further assess bone metabolism in hibernating black bears. Using the same serum markers of bone remodeling used to evaluate human patients with osteoporosis, we assayed serum from five black bears, collected every 10 days over a 196-day period, for bone resorption and formation markers. Here we show that bone resorption remains elevated over the entire hibernation period compared to the pre-hibernation period, but osteoblastic bone formation is not impaired by hibernation and is rapidly accelerated during remobilization following hibernation.

  2. Longitudinal in vivo imaging of bone formation and resorption using fluorescence molecular tomography.

    PubMed

    Lambers, F M; Stuker, F; Weigt, C; Kuhn, G; Koch, K; Schulte, F A; Ripoll, J; Rudin, M; Müller, R

    2013-02-01

    Bone research often focuses on anatomical imaging of the bone microstructure, but in order to gain better understanding in how bone remodeling is modulated through interventions also bone formation and resorption processes should be investigated. With this in mind, the purpose of this study was to establish a longitudinal in vivo imaging approach of bone formation and resorption using fluorescence molecular tomography (FMT). In this study the reproducibility, accuracy and sensitivity of FMT for bone imaging were assessed by performing longitudinal measurements with FMT and comparing it to in vivo micro-computed tomography on a set of control mice, and mice in which load-adaptation was induced in the sixth caudal vertebra. The precision error for FMT measurements, expressed as coefficient of variation, was smaller than 16%, indicating acceptable reproducibility. A correlation was found between bone resorption measured with FMT and bone resorption rate measured with in vivo micro-computed tomography only over the first 14days (R=0.81, p<0.01), but not between bone formation measured with FMT and bone formation rate measured with in vivo micro-CT. Bone formation measured by FMT was 89-109% greater (p<0.05) for mice subjected to mechanical loading than control mice. Bone resorption was 5-8% lower, but did not reach a significant difference between groups, indicating moderate sensitivity for FMT. In conclusion, in vivo FMT in mouse tail bones is feasible but needs to be optimized for monitoring load adaptation in living mice.

  3. Mesenchyme-specific overexpression of nucleolar protein 66 in mice inhibits skeletal growth and bone formation

    PubMed Central

    Chen, Qin; Zhang, Liping; de Crombrugghe, Benoit; Krahe, Ralf

    2015-01-01

    Previous studies showed that nucleolar protein 66 (NO66), the Jumonji C-domain-containing histone demethylase for methylated histone H3K4 and H3K36 (H3K36me), negatively regulates osteoblast differentiation in vitro by inhibiting the activity of transcription factor osterix (Osx). However, whether NO66 affects mammalian skeletogenesis in vivo is not yet known. Here, we generated transgenic (TG) mice overexpressing a flag-tagged NO66 transgene driven by the Prx1 (paired related homeobox 1) promoter. We found that NO66 overexpression in Prx1-expressing mesenchymal cells inhibited skeletal growth and bone formation. The inhibitory phenotype was associated with >50% decreases in chondrocyte/osteoblast proliferation and differentiation. Moreover, we found that in bones of NO66-TG mice, expression of Igf1, Igf1 receptor (Igf1r), runt-related transcription factor 2, and Osx was significantly down-regulated (P < 0.05). Consistent with these results, we observed >50% reduction in levels of phosphorylated protein kinase B (Akt) and H3K36me3 in bones of NO66-TG mice, suggesting an inverse correlation between NO66 histone demethylase and the activity of IGF1R/Akt signaling. This correlation was further confirmed by in vitro assays of C2C12 cells with NO66 overexpression. We propose that the decrease in the IGF1R/Akt signaling pathway in mice with mesenchymal overexpression of NO66 may contribute in part to the inhibition of skeletal growth and bone formation.—Chen, Q., Zhang, L., de Crombrugghe, B., Krahe, R. Mesenchyme-specific overexpression of nucleolar protein 66 in mice inhibits skeletal growth and bone formation. PMID:25746793

  4. Physical characteristics affecting the tensile failure properties of compact bone.

    PubMed

    Currey, J D

    1990-01-01

    Compact bone specimens from a wide variety of reptiles, birds, and mammals were tested in tension, and their failure properties related to mineral volume fraction, porosity and histological orientation. The principal findings were that the ultimate strain and the work under the stress-strain curve declined sharply with mineralisation, as did the stress and strain appearing after the specimen had yielded. Ultimate tensile strength was not simply related to any combination of the possible explanatory variables, but some relatively poorly mineralised bones, notably antlers, had high stresses at failure. These high strengths were allowed by a great increase in stress after the bones had yielded at quite low stresses.

  5. Pyridoxine deficiency affects biomechanical properties of chick tibial bone

    NASA Technical Reports Server (NTRS)

    Masse, P. G.; Rimnac, C. M.; Yamauchi, M.; Coburn, S. P.; Rucker, R. B.; Howell, D. S.; Boskey, A. L.

    1996-01-01

    The mechanical integrity of bone is dependent on the bone matrix, which is believed to account for the plastic deformation of the tissue, and the mineral, which is believed to account for the elastic deformation. The validity of this model is shown in this study based on analysis of the bones of vitamin B6-deficient and vitamin B6-replete chick bones. In this model, when B6-deficient and control animals are compared, vitamin B6 deficiency has no effect on the mineral content or composition of cortical bone as measured by ash weight (63 +/- 6 vs. 58 +/- 3); mineral to matrix ratio of the FTIR spectra (4.2 +/- 0.6 vs. 4.5 +/- 0.2), line-broadening analyses of the X-ray diffraction 002 peak (beta 002 = 0.50 +/- 0.1 vs. 0.49 +/- 0.01), or other features of the infrared spectra. In contrast, collagen was significantly more extractable from vitamin B6-deficient chick bones (20 +/- 2% of total hydroxyproline extracted vs. 10 +/- 3% p < or = 0.001). The B6-deficient bones also contained an increased amount of the reducible cross-links DHLNL, dehydro-dihydroxylysinonorleucine, (1.03 +/- 0.07 vs. 0.84 +/- 0.13 p < or = 0.001); and a nonsignificant increase in HLNL, dehydro-hydroxylysinonorleucine, (0.51 +/- 0.03 vs. 0.43 +/- 0.03, p < or = 0.10). There were no significant changes in bone length, bone diameter, or area moment of inertia. In four-point bending, no significant changes in elastic modulus, stiffness, offset yield deflection, or fracture deflection were detected. However, fracture load in the B6-deficient animals was decreased from 203 +/- 35 MPa to 151 +/- 23 MPa, p < or = 0.01, and offset yield load was decreased from 165 +/- 9 MPa to 125 +/- 14 MPa, p < or = 0.05. Since earlier histomorphometric studies had demonstrated that the B6-deficient bones were osteopenic, these data suggest that although proper cortical bone mineralization occurred, the alterations of the collagen resulted in changes to bone mechanical performance.

  6. Bone volume fraction explains the variation in strength and stiffness of cancellous bone affected by metastatic cancer and osteoporosis.

    PubMed

    Nazarian, Ara; von Stechow, Dietrich; Zurakowski, David; Müller, Ralph; Snyder, Brian D

    2008-12-01

    Preventing nontraumatic fractures in millions of patients with osteoporosis or metastatic cancer may significantly reduce the associated morbidity and reduce health-care expenditures incurred by these fractures. Predicting fracture occurrence requires an accurate understanding of the relationship between bone structure and the mechanical properties governing bone fracture that can be readily measured. The aim of this study was to test the hypothesis that a single analytic relationship with either bone tissue mineral density or bone volume fraction (BV/TV) as independent variables could predict the strength and stiffness of normal and pathologic cancellous bone affected by osteoporosis or metastatic cancer. After obtaining institutional review board approval and informed consent, 15 patients underwent excisional biopsy of metastatic prostate, breast, lung, ovarian, or colon cancer from the spine and/or femur to obtain 41 metastatic cancer specimens. In addition, 96 noncancer specimens were excised from 43 age- and site-matched cadavers. All specimens were imaged using micro-computed tomography (micro-CT) and backscatter emission imaging and tested mechanically by uniaxial compression and nanoindentation. The minimum BV/TV, measured using quantitative micro-CT, accounted for 84% of the variation in bone stiffness and strength for all cancellous bone specimens. While relationships relating bone density to strength and stiffness have been derived empirically for normal and osteoporotic bone, these relationships have not been applied to skeletal metastases. This simple analytic relationship will facilitate large-scale screening and prediction of fracture risk for normal and pathologic cancellous bone using clinical CT systems to determine the load capacity of bones altered by metastatic cancer, osteoporosis, or both.

  7. Expression of bone morphogenetic proteins and cartilage-derived morphogenetic proteins during osteophyte formation in humans

    PubMed Central

    Zoricic, Sanja; Maric, Ivana; Bobinac, Dragica; Vukicevic, Slobodan

    2003-01-01

    Bone- and cartilage-derived morphogenetic proteins (BMPs and CDMPs), which are TGFβ superfamily members, are growth and differentiation factors that have been recently isolated, cloned and biologically characterized. They are important regulators of key events in the processes of bone formation during embryogenesis, postnatal growth, remodelling and regeneration of the skeleton. In the present study, we used immunohistochemical methods to investigate the distribution of BMP-2, -3, -5, -6, -7 and CDMP-1, -2, -3 in human osteophytes (abnormal bony outgrowths) isolated from osteoarthritic hip and knee joints from patients undergoing total joint replacement surgery. All osteophytes consisted of three different areas of active bone formation: (1) endochondral bone formation within cartilage residues; (2) intramembranous bone formation within the fibrous tissue cover and (3) bone formation within bone marrow spaces. The immunohistochemistry of certain BMPs and CDMPs in each of these three different bone formation sites was determined. The results indicate that each BMP has a distinct pattern of distribution. Immunoreactivity for BMP-2 was observed in fibrous tissue matrix as well as in osteoblasts; BMP-3 was mainly present in osteoblasts; BMP-6 was restricted to young osteocytes and bone matrix; BMP-7 was observed in hypertrophic chondrocytes, osteoblasts and young osteocytes of both endochondral and intramembranous bone formation sites. CDMP-1, -2 and -3 were strongly expressed in all cartilage cells. Surprisingly, BMP-3 and -6 were found in osteoclasts at the sites of bone resorption. Since a similar distribution pattern of bone morphogenetic proteins was observed during embryonal bone development, it is suggested that osteophyte formation is regulated by the same molecular mechanism as normal bone during embryogenesis. PMID:12713267

  8. Cyclic cryopreservation affects the nanoscale material properties of trabecular bone.

    PubMed

    Landauer, Alexander K; Mondal, Sumona; Yuya, Philip A; Kuxhaus, Laurel

    2014-11-07

    Tissues such as bone are often stored via freezing, or cryopreservation. During an experimental protocol, bone may be frozen and thawed a number of times. For whole bone, the mechanical properties (strength and modulus) do not significantly change throughout five freeze-thaw cycles. Material properties at the trabecular and lamellar scales are distinct from whole bone properties, thus the impact of freeze-thaw cycling at this scale is unknown. To address this, the effect of repeated freezing on viscoelastic material properties of trabecular bone was quantified via dynamic nanoindentation. Vertebrae from five cervine spines (1.5-year-old, male) were semi-randomly assigned, three-to-a-cycle, to 0-10 freeze-thaw cycles. After freeze-thaw cycling, the vertebrae were dissected, prepared and tested. ANOVA (factors cycle, frequency, and donor) on storage modulus, loss modulus, and loss tangent, were conducted. Results revealed significant changes between cycles for all material properties for most cycles, no significant difference across most of the dynamic range, and significant differences between some donors. Regression analysis showed a moderate positive correlation between cycles and material property for loss modulus and loss tangent, and weak negative correlation for storage modulus, all correlations were significant. These results indicate that not only is elasticity unpredictably altered, but also that damping and viscoelasticity tend to increase with additional freeze-thaw cycling.

  9. Marked increase in bone formation markers after cinacalcet treatment by mechanisms distinct from hungry bone syndrome in a haemodialysis patient

    PubMed Central

    Goto, Shunsuke; Fujii, Hideki; Matsui, Yutaka; Fukagawa, Masafumi

    2010-01-01

    A 59-year-old female who was on dialysis due to diabetic nephropathy was referred to our hospital for severe hyperparathyroidism refractory to intravenous vitamin D receptor activator treatment. With subsequent cinacalcet hydrochloride treatment, parathyroid hormone (PTH) levels were only slightly suppressed. However, progressive increases were observed in serum alkaline phosphatase (ALP) and bone-specific alkaline phosphatase (BAP) levels with mild hypocalcaemia. A bone biopsy, obtained immediately before surgical parathyroidectomy after 3 months of cinacalcet treatment, revealed no disappearance of osteoclasts. These data suggest that cinacalcet hydrochloride treatment may induce a marked promotion of bone formation by mechanisms distinct from hungry bone syndrome that usually develops after parathyroidectomy. PMID:25949410

  10. Bisphosphonate-adsorbed ceramic nanoparticles increase bone formation in an injectable carrier for bone tissue engineering

    PubMed Central

    Cheng, Tegan L; Murphy, Ciara M; Ravarian, Roya; Dehghani, Fariba; Little, David G; Schindeler, Aaron

    2015-01-01

    Sucrose acetate isobutyrate (SAIB) is a sugar-based carrier. We have previously applied SAIB as a minimally invasive system for the co-delivery of recombinant human bone morphogenetic protein-2 (rhBMP-2) and found synergy when co-delivering zoledronic acid (ZA) and hydroxyapatite (HA) nanoparticles. Alternative bioceramics were investigated in a murine SAIB/rhBMP-2 injection model. Neither beta-tricalcium phosphate (TCP) nor Bioglass (BG) 45S5 had a significant effect on bone volume (BV) alone or in combination with the ZA. 14C-labelled ZA binding assays showed particle size and ceramic composition affected binding with nano-HA > micro-HA > TCP > BG. Micro-HA and nano-HA increased BV in a rat model of rhBMP-2/SAIB injection (+278% and +337%), and BV was further increased with ZA–adsorbed micro-HA and nano-HA (+530% and +889%). These data support the use of ZA–adsorbed nanoparticle-sized HA as an optimal additive for the SAIB/rhBMP-2 injectable system for bone tissue engineering. PMID:26668709

  11. Wnt signaling in bone formation and its therapeutic potential for bone diseases

    PubMed Central

    Kim, Jeong Hwan; Liu, Xing; Wang, Jinhua; Chen, Xiang; Zhang, Hongyu; Kim, Stephanie H.; Cui, Jing; Li, Ruidong; Zhang, Wenwen; Kong, Yuhan; Zhang, Jiye; Shui, Wei; Lamplot, Joseph; Rogers, Mary Rose; Zhao, Chen; Wang, Ning; Rajan, Prashant; Tomal, Justin; Statz, Joseph; Wu, Ningning; Luu, Hue H.; Haydon, Rex C.

    2013-01-01

    The Wnt signaling pathway plays an important role not only in embryonic development but also in the maintenance and differentiation of the stem cells in adulthood. In particular, Wnt signaling has been shown as an important regulatory pathway in the osteogenic differentiation of mesenchymal stem cells. Induction of the Wnt signaling pathway promotes bone formation while inactivation of the pathway leads to osteopenic states. Our current understanding of Wnt signaling in osteogenesis elucidates the molecular mechanisms of classic osteogenic pathologies. Activating and inactivating aberrations of the canonical Wnt signaling pathway in osteogenesis results in sclerosteosis and osteoporosis respectively. Recent studies have sought to target the Wnt signaling pathway to treat osteogenic disorders. Potential therapeutic approaches attempt to stimulate the Wnt signaling pathway by upregulating the intracellular mediators of the Wnt signaling cascade and inhibiting the endogenous antagonists of the pathway. Antibodies against endogenous antagonists, such as sclerostin and dickkopf-1, have demonstrated promising results in promoting bone formation and fracture healing. Lithium, an inhibitor of glycogen synthase kinase 3β, has also been reported to stimulate osteogenesis by stabilizing β catenin. Although manipulating the Wnt signaling pathway has abundant therapeutic potential, it requires cautious approach due to risks of tumorigenesis. The present review discusses the role of the Wnt signaling pathway in osteogenesis and examines its targeted therapeutic potential. PMID:23514963

  12. Effect of processing conditions of dicalcium phosphate cements on graft resorption and bone formation.

    PubMed

    Sheikh, Zeeshan; Zhang, Yu Ling; Tamimi, Faleh; Barralet, Jake

    2017-02-15

    Dicalcium phosphate cements (brushite and monetite) are resorbable biomaterials with osteoconductive potential for bone repair and regeneration that have yet to gain widespread commercial use. Brushite can be converted to monetite by heat treatments additionally resulting in various changes in the physico-chemical properties. However, since conversion is most commonly performed using autoclave sterilisation (wet heating), it is uncertain whether the properties observed for monetite as a result of heating brushite under dry conditions affect resorption and bone formation favourably. This study was designed to produce monetite grafts of differing physical form by autoclaving and dry heating (under vacuum) to be compared with brushite biomaterials in an orthotopic pre-clinical implantation model in rabbit for 12weeks. It was observed that monetite grafts had higher porosity and specific surface area than their brushite precursors. The autoclaved monetite grafts had compressive strength reduced by 50% when compared with their brushite precursors. However, the dry heat converted monetite grafts had compressive strength comparable with brushite. Results from in vivo experiments revealed that both types of monetite graft materials resorbed faster than brushite and more bone formation was achieved. There was no significant difference in the amount of bone formed between the two types of monetite grafts. The implanted brushite grafts underwent phase transformation to form hydroxyapatite, which ultimately limited bioresorption. However, this was not observed in both types of monetite grafts. In summary, both autoclaving and dry heating the preset brushite cement grafts resulted in monetite biomaterials which were more resorbable with potential to be investigated and optimized for orthopaedic and maxillofacial bone repair and regeneration applications.

  13. Relative bone mass decreased in mice fed high dietary fat despite an increase in body mass and bone formation markers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Osteoporosis and obesity are interrelated health disorders. Osteoblasts and adipocytes are derived from common mesenchymal stem cells and age-related osteoporosis is associated with increased bone marrow adipogenesis. To determine whether bone mass and osteoblast number and activity are affected by ...

  14. Carbon nanotubes functionalized with fibroblast growth factor accelerate proliferation of bone marrow-derived stromal cells and bone formation

    NASA Astrophysics Data System (ADS)

    Hirata, Eri; Ménard-Moyon, Cécilia; Venturelli, Enrica; Takita, Hiroko; Watari, Fumio; Bianco, Alberto; Yokoyama, Atsuro

    2013-11-01

    Multi-walled carbon nanotubes (MWCNTs) were functionalized with fibroblast growth factor (FGF) and the advantages of their use as scaffolds for bone augmentation were evaluated in vitro and in vivo. The activity of FGF was assessed by measuring the effect on the proliferation of rat bone marrow stromal cells (RBMSCs). The presence of FGF enhanced the proliferation of RBMSCs and the FGF covalently conjugated to the nanotubes (FGF-CNT) showed the same effect as FGF alone. In addition, FGF-CNT coated sponges were implanted between the parietal bone and the periosteum of rats and the formation of new bone was investigated. At day 14 after implantation, a larger amount of newly formed bone was clearly observed in most pores of FGF-CNT coated sponges. These findings indicated that MWCNTs accelerated new bone formation in response to FGF, as well as the integration of particles into new bone during its formation. Scaffolds coated with FGF-CNT could be considered as promising novel substituting materials for bone regeneration in future tissue engineering applications.

  15. Reduced bone formation markers, and altered trabecular and cortical bone mineral densities of non-paretic femurs observed in rats with ischemic stroke: A randomized controlled pilot study

    PubMed Central

    Rewell, Sarah S.; Iuliano, Sandra; Ghasem-Zadeh, Ali; Davey, Rachel A.; Ho, Heidi; Skeers, Peta N.; Bernhardt, Julie; Howells, David W.

    2017-01-01

    Background Immobility and neural damage likely contribute to accelerated bone loss after stroke, and subsequent heightened fracture risk in humans. Objective To investigate the skeletal effect of middle cerebral artery occlusion (MCAo) stroke in rats and examine its utility as a model of human post-stroke bone loss. Methods Twenty 15-week old spontaneously hypertensive male rats were randomized to MCAo or sham surgery controls. Primary outcome: group differences in trabecular bone volume fraction (BV/TV) measured by Micro-CT (10.5 micron istropic voxel size) at the ultra-distal femur of stroke affected left legs at day 28. Neurological impairments (stroke behavior and foot-faults) and physical activity (cage monitoring) were assessed at baseline, and days 1 and 27. Serum bone turnover markers (formation: N-terminal propeptide of type 1 procollagen, PINP; resorption: C-terminal telopeptide of type 1 collagen, CTX) were assessed at baseline, and days 7 and 27. Results No effect of stroke was observed on BV/TV or physical activity, but PINP decreased by -24.5% (IQR -34.1, -10.5, p = 0.046) at day 27. In controls, cortical bone volume (5.2%, IQR 3.2, 6.9) and total volume (6.4%, IQR 1.2, 7.6) were higher in right legs compared to left legs, but these side-to-side differences were not evident in stroke animals. Conclusion MCAo may negatively affect bone formation. Further investigation of limb use and physical activity patterns after MCAo is required to determine the utility of this current model as a representation of human post-stroke bone loss. PMID:28278253

  16. When size matters: differences in demineralized bone matrix particles affect collagen structure, mesenchymal stem cell behavior, and osteogenic potential.

    PubMed

    Dozza, B; Lesci, I G; Duchi, S; Della Bella, E; Martini, L; Salamanna, F; Falconi, M; Cinotti, S; Fini, M; Lucarelli, E; Donati, D

    2017-04-01

    Demineralized bone matrix (DBM) is a natural, collagen-based, osteoinductive biomaterial. Nevertheless, there are conflicting reports on the efficacy of this product. The purpose of this study was to evaluate whether DBM collagen structure is affected by particle size and can influence DBM cytocompatibility and osteoinductivity. Sheep cortical bone was ground and particles were divided in three fractions with different sizes, defined as large (L, 1-2 mm), medium (M, 0.5-1 mm), and small (S, <0.5 mm). After demineralization, the chemical-physical analysis clearly showed a particle size-dependent alteration in collagen structure, with DBM-M being altered but not as much as DBM-S. DBM-M displayed a preferable trend in almost all biological characteristics tested, although all DBM particles revealed an optimal cytocompatibility. Subcutaneous implantation of DBM particles into immunocompromised mice resulted in bone induction only for DBM-M. When sheep MSC were seeded onto particles before implantation, all DBM particles were able to induce new bone formation with the best incidence for DBM-M and DBM-S. In conclusion, the collagen alteration in DBM-M is likely the best condition to promote bone induction in vivo. Furthermore, the choice of 0.5-1 mm particles may enable to obtain more efficient and consistent results among different research groups in bone tissue-engineering applications. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1019-1033, 2017.

  17. Subtle changes in bone mineralization density distribution in most severely affected patients with chronic obstructive pulmonary disease.

    PubMed

    Misof, B M; Roschger, P; Jorgetti, V; Klaushofer, K; Borba, V Z C; Boguszewski, C L; Cohen, A; Shane, E; Zhou, H; Dempster, D W; Moreira, C A

    2015-10-01

    Chronic obstructive pulmonary disease (COPD) is associated with low aBMD as measured by DXA and altered microstructure as assessed by bone histomorphometry and microcomputed tomography. Knowledge of bone matrix mineralization is lacking in COPD. Using quantitative backscatter electron imaging (qBEI), we assessed cancellous (Cn.) and cortical (Ct.) bone mineralization density distribution (BMDD) in 19 postmenopausal women (62.1 ± 7.3 years of age) with COPD. Eight had sustained fragility fractures, and 13 had received treatment with inhaled glucocorticoids. The BMDD outcomes from the patients were compared with healthy reference data and were correlated with previous clinical and histomorphometric findings. In general, the BMDD outcomes for the patients were not significantly different from the reference data. Neither the subgroups of with or without fragility fractures or of who did or did not receive inhaled glucocorticoid treatment, showed differences in BMDD. However, subgroup comparison according to severity revealed 10% decreased cancellous mineralization heterogeneity (Cn.CaWidth) for the most severely affected compared with less affected patients (p=0.042) and compared with healthy premenopausal controls (p=0.021). BMDD parameters were highly correlated with histomorphometric cancellous bone volume (BV/TV) and formation indices: mean degree of mineralization (Cn.CaMean) versus BV/TV (r=0.58, p=0.009), and Cn.CaMean and Ct.CaMean versus bone formation rate (BFR/BS) (r=-0.71, p<0.001). In particular, those with lower BV/TV (<50th percentile) had significantly lower Cn.CaMean (p=0.037) and higher Cn.CaLow (p=0.020) compared with those with higher (>50th percentile) BV/TV. The normality in most of the BMDD parameters and bone formation rates as well as the significant correlations between them suggests unaffected mineralization processes in COPD. Our findings also indicate no significant negative effect of treatment with inhaled glucocorticoids on the bone

  18. Connexin 43 deficiency attenuates loss of trabecular bone and prevents suppression of cortical bone formation during unloading.

    PubMed

    Lloyd, Shane A; Lewis, Gregory S; Zhang, Yue; Paul, Emmanuel M; Donahue, Henry J

    2012-11-01

    Connexin 43 (Cx43) is the most abundant gap junction protein in bone and has been demonstrated as an integral component of skeletal homeostasis. In the present study, we sought to further refine the role of Cx43 in the response to mechanical unloading by subjecting skeletally mature mice with a bone-specific deletion of Cx43 (cKO) to 3 weeks of mechanical unloading via hindlimb suspension (HLS). The HLS model was selected to recapitulate the effects of skeletal unloading due to prolonged bed rest, reduced activity associated with aging, and spaceflight microgravity. At baseline, the cortical bone of cKO mice displayed an osteopenic phenotype, with expanded cortices, decreased cortical thickness, decreased bone mineral density, and increased porosity. There was no baseline trabecular phenotype. After 3 weeks of HLS, wild-type (WT) mice experienced a substantial decline in trabecular bone volume fraction, connectivity density, trabecular thickness, and trabecular tissue mineral density. These deleterious effects were attenuated in cKO mice. Conversely, there was a similar and significant amount of cortical bone loss in both WT and cKO. Interestingly, mechanical testing revealed a greater loss of strength and rigidity for cKO during HLS. Analysis of double-label quantitative histomorphometry data demonstrated a substantial decrease in bone formation rate, mineralizing surface, and mineral apposition rate at both the periosteal and endocortical surfaces of the femur after unloading of WT mice. This suppression of bone formation was not observed in cKO mice, in which parameters were maintained at baseline levels. Taken together, the results of the present study indicate that Cx43 deficiency desensitizes bone to the effects of mechanical unloading, and that this may be due to an inability of mechanosensing osteocytes to effectively communicate the unloading state to osteoblasts to suppress bone formation. Cx43 may represent a novel therapeutic target for investigation as

  19. Evaluation of bone formation guided by DNA/protamine complex with FGF-2 in an adult rat calvarial defect model.

    PubMed

    Shinozaki, Yosuke; Toda, Masako; Ohno, Jun; Kawaguchi, Minoru; Kido, Hirofumi; Fukushima, Tadao

    2014-11-01

    DNA/protamine complex paste (D/P) and D/P complex paste with Fibroblast Growth Factor-2 (FGF-2) (D/P-FGF) were prepared to investigate their new bone formation abilities using an ∼40-week-old rat calvarial defect model. It was found that D/P could release FGF-2 proportionally in an in vitro experiment with an enzyme-linked immunosorbent assay. It was also found that aging adversely affected self-bone healing of rats by comparison with the results in a previous study using 10-week-old rats. Microcomputed tomography and histopathological examinations showed that new bone formation abilities of D/P and D/P-FGF were superior to that of the control (sham operation). Control, D/P and D/P-FGF showed newly formed bone areas of 6.7, 58.3, and 67.0%, respectively, 3 months after the operation. Moreover, it was found that FGF-2 could support the osteoanagenesis ability of D/P. It was considered that FGF-2 could play an important role in new bone formation at early stages because it induced the genes such as collagen I, CBFA, OSX, and OPN, which are initiated first in the process of osteogenesis. Therefore, D/P-FGF will be a useful injectable biomaterial with biodegradable properties for the repair of bone defects in the elderly.

  20. Does aspiration of bones and joints affect results of later bone scanning

    SciTech Connect

    Canale, S.T.; Harkness, R.M.; Thomas, P.A.; Massie, J.D.

    1985-01-01

    To determine the effect, if any, of needle aspiration on /sup 99m/Tc bone scanning, three different areas of 15 dogs were first aspirated and then imaged with technetium bone scintigraphy. The hip joint was aspirated, the distal femoral metaphysis was drilled and aspirated, and the tibial periosteum was scraped with an 18- or 20-gauge needle. Varying amounts of trauma were inflicted to simulate varying difficulties at aspiration. /sup 99m/Tc bone scans were obtained from 5 h to 10 days later. There was no evidence of focal technetium uptake after any hip joint aspiration. This was consistent regardless of the amount of trauma inflicted or the time from aspiration to bone scanning. Metaphyseal cortical drilling and tibial periosteal scraping occasionally caused some focal uptake when scanning was delayed greater than 2 days. When osteomyelitis or pyarthrosis is clinically suspected, joint aspiration can be performed without fear of producing a false- positive bone scan.

  1. Adenoviral Mediated Expression of BMP2 by Bone Marrow Stromal Cells Cultured in 3D Copolymer Scaffolds Enhances Bone Formation

    PubMed Central

    Sharma, Sunita; Sapkota, Dipak; Xue, Ying; Sun, Yang; Finne-Wistrand, Anna; Bruland, Ove; Mustafa, Kamal

    2016-01-01

    Selection of appropriate osteoinductive growth factors, suitable delivery method and proper supportive scaffold are critical for a successful outcome in bone tissue engineering using bone marrow stromal cells (BMSC). This study examined the molecular and functional effect of a combination of adenoviral mediated expression of bone morphogenetic protein-2 (BMP2) in BMSC and recently developed and characterized, biodegradable Poly(L-lactide-co-є-caprolactone){poly(LLA-co-CL)}scaffolds in osteogenic molecular changes and ectopic bone formation by using in vitro and in vivo approaches. Pathway-focused custom PCR array, validation using TaqMan based quantitative RT-PCR (qRT-PCR) and ALP staining showed significant up-regulation of several osteogenic and angiogenic molecules, including ALPL and RUNX2 in ad-BMP2 BMSC group grown in poly(LLA-co-CL) scaffolds both at 3 and 14 days. Micro CT and histological analyses of the subcutaneously implanted scaffolds in NOD/SCID mice revealed significantly increased radiopaque areas, percentage bone volume and formation of vital bone in ad-BMP2 scaffolds as compared to the control groups both at 2 and 8 weeks. The increased bone formation in the ad-BMP2 group in vivo was paralleled at the molecular level with concomitant over-expression of a number of osteogenic and angiogenic genes including ALPL, RUNX2, SPP1, ANGPT1. The increased bone formation in ad-BMP2 explants was not found to be associated with enhanced endochondral activity as evidenced by qRT-PCR (SOX9 and FGF2) and Safranin O staining. Taken together, combination of adenoviral mediated BMP-2 expression in BMSC grown in the newly developed poly(LLA-co-CL) scaffolds induced expression of osteogenic markers and enhanced bone formation in vivo. PMID:26808122

  2. Clodronate stimulates bone formation as well as inhibits bone resorption and increases bone mineral density in rats fed a low-calcium diet.

    PubMed

    Horie, Daisuke; Takahashi, Mariko; Aoki, Kazuhiro; Ohya, Keiichi

    2003-03-01

    The pharmacological actions of bisphosphonates are due to the inhibitory effects on bone resorption, but little is known about the bisphosphonate action on bone formation. The purpose of this study is to elucidate the actions of bisphosphonates, clodronate, on bone formation in the experimental in vivo and in vitro rat models. The bone mineral density (BMD) was decreased in the rats fed a low-calcium diet (0.05% Ca) for 6 days compared with the rats fed a normal-calcium diet (0.5% Ca). The decrease in BMD was suppressed in the 2 mgP/day and the 4 mgP/day clodronate administrations. Bone formation rate (BFR) in rats fed a low-calcium diet was significantly increased compared with the rats fed a normal-calcium diet, and the 2 mgP clodronate administration further increased the BFR. In the cultured rat bone marrow cells, the area of mineralized nodules was significantly increased at 10(-7) and 10(-6) M clodronate, but high concentration of clodronate decreased the area. From these results, it is concluded that clodronate stimulates bone formation when the drug was given to a rat with a relatively lower dose that is sufficient to prevent bone resorption and that this effect may be due to the stimulatory effect on the differentiation process of osteoblasts.

  3. A primary phosphorus‐deficient skeletal phenotype in juvenile Atlantic salmon Salmo salar: the uncoupling of bone formation and mineralization

    PubMed Central

    Owen, M. A. G.; Fontanillas, R.; Soenens, M.; McGurk, C.; Obach, A.

    2015-01-01

    To understand the effect of low dietary phosphorus (P) intake on the vertebral column of Atlantic salmon Salmo salar, a primary P deficiency was induced in post‐smolts. The dietary P provision was reduced by 50% for a period of 10 weeks under controlled conditions. The animal's skeleton was subsequently analysed by radiology, histological examination, histochemical detection of minerals in bones and scales and chemical mineral analysis. This is the first account of how a primary P deficiency affects the skeleton in S. salar at the cellular and at the micro‐anatomical level. Animals that received the P‐deficient diet displayed known signs of P deficiency including reduced growth and soft, pliable opercula. Bone and scale mineral content decreased by c. 50%. On radiographs, vertebral bodies appear small, undersized and with enlarged intervertebral spaces. Contrary to the X‐ray‐based diagnosis, the histological examination revealed that vertebral bodies had a regular size and regular internal bone structures; intervertebral spaces were not enlarged. Bone matrix formation was continuous and uninterrupted, albeit without traces of mineralization. Likewise, scale growth continues with regular annuli formation, but new scale matrix remains without minerals. The 10 week long experiment generated a homogeneous osteomalacia of vertebral bodies without apparent induction of skeletal malformations. The experiment shows that bone formation and bone mineralization are, to a large degree, independent processes in the fish examined. Therefore, a deficit in mineralization must not be the only cause of the alterations of the vertebral bone structure observed in farmed S. salar. It is discussed how the observed uncoupling of bone formation and mineralization helps to better diagnose, understand and prevent P deficiency‐related malformations in farmed S. salar. PMID:26707938

  4. A primary phosphorus-deficient skeletal phenotype in juvenile Atlantic salmon Salmo salar: the uncoupling of bone formation and mineralization.

    PubMed

    Witten, P E; Owen, M A G; Fontanillas, R; Soenens, M; McGurk, C; Obach, A

    2016-02-01

    To understand the effect of low dietary phosphorus (P) intake on the vertebral column of Atlantic salmon Salmo salar, a primary P deficiency was induced in post-smolts. The dietary P provision was reduced by 50% for a period of 10 weeks under controlled conditions. The animal's skeleton was subsequently analysed by radiology, histological examination, histochemical detection of minerals in bones and scales and chemical mineral analysis. This is the first account of how a primary P deficiency affects the skeleton in S. salar at the cellular and at the micro-anatomical level. Animals that received the P-deficient diet displayed known signs of P deficiency including reduced growth and soft, pliable opercula. Bone and scale mineral content decreased by c. 50%. On radiographs, vertebral bodies appear small, undersized and with enlarged intervertebral spaces. Contrary to the X-ray-based diagnosis, the histological examination revealed that vertebral bodies had a regular size and regular internal bone structures; intervertebral spaces were not enlarged. Bone matrix formation was continuous and uninterrupted, albeit without traces of mineralization. Likewise, scale growth continues with regular annuli formation, but new scale matrix remains without minerals. The 10 week long experiment generated a homogeneous osteomalacia of vertebral bodies without apparent induction of skeletal malformations. The experiment shows that bone formation and bone mineralization are, to a large degree, independent processes in the fish examined. Therefore, a deficit in mineralization must not be the only cause of the alterations of the vertebral bone structure observed in farmed S. salar. It is discussed how the observed uncoupling of bone formation and mineralization helps to better diagnose, understand and prevent P deficiency-related malformations in farmed S. salar.

  5. Abdominal Fat Is Associated With Lower Bone Formation and Inferior Bone Quality in Healthy Premenopausal Women: A Transiliac Bone Biopsy Study

    PubMed Central

    Dempster, David W.; Recker, Robert R.; Lappe, Joan M.; Zhou, Hua; Zwahlen, Alexander; Müller, Ralph; Zhao, Binsheng; Guo, Xiaotao; Lang, Thomas; Saeed, Isra; Liu, X. Sherry; Guo, X. Edward; Cremers, Serge; Rosen, Clifford J.; Stein, Emily M.; Nickolas, Thomas L.; McMahon, Donald J.; Young, Polly; Shane, Elizabeth

    2013-01-01

    Context: The conventional view that obesity is beneficial for bone strength has recently been challenged by studies that link obesity, particularly visceral obesity, to low bone mass and fractures. It is controversial whether effects of obesity on bone are mediated by increased bone resorption or decreased bone formation. Objective: The objective of the study was to evaluate bone microarchitecture and remodeling in healthy premenopausal women of varying weights. Design: We measured bone density and trunk fat by dual-energy x-ray absorptiometry in 40 women and by computed tomography in a subset. Bone microarchitecture, stiffness, remodeling, and marrow fat were assessed in labeled transiliac bone biopsies. Results: Body mass index (BMI) ranged from 20.1 to 39.2 kg/m2. Dual-energy x-ray absorptiometry-trunk fat was directly associated with BMI (r = 0.78, P < .001) and visceral fat by computed tomography (r = 0.79, P < .001). Compared with women in the lowest tertile of trunk fat, those in the highest tertile had inferior bone quality: lower trabecular bone volume (20.4 ± 5.8 vs 29.1 ± 6.1%; P = .001) and stiffness (433 ± 264 vs 782 ± 349 MPa; P = .01) and higher cortical porosity (8.8 ± 3.5 vs 6.3 ± 2.4%; P = .049). Bone formation rate (0.004 ± 0.002 vs 0.011 ± 0.008 mm2/mm · year; P = .006) was 64% lower in the highest tertile. Trunk fat was inversely associated with trabecular bone volume (r = −0.50; P < .01) and bone formation rate (r = −0.50; P < .001). The relationship between trunk fat and bone volume remained significant after controlling for age and BMI. Conclusions: At the tissue level, premenopausal women with more central adiposity had inferior bone quality and stiffness and markedly lower bone formation. Given the rising levels of obesity, these observations require further investigation. PMID:23515452

  6. Deficient Neutrophil Extracellular Trap Formation in Patients Undergoing Bone Marrow Transplantation.

    PubMed

    Glenn, Jared W; Cody, Mark J; McManus, Meghann P; Pulsipher, Michael A; Schiffman, Joshua D; Yost, Christian Con

    2016-01-01

    Overwhelming infection causes significant morbidity and mortality among patients treated with bone marrow transplantation (BMT) for primary immune deficiencies, syndromes of bone marrow failure, or cancer. The polymorphonuclear leukocyte (PMN; neutrophil) is the first responder to microbial invasion and acts within the innate immune system to contain and clear infections. PMNs contain, and possibly clear, infections in part by forming neutrophil extracellular traps (NETs). NETs are extensive lattices of extracellular DNA and decondensed chromatin decorated with antimicrobial proteins and degradative enzymes, such as histones, myeloperoxidase, and neutrophil elastase. They trap and contain microbes, including bacteria and fungi, and may directly affect extracellular microbial killing. Whether or not deficient NET formation contributes to the increased risk for overwhelming infection in patients undergoing BMT remains incompletely characterized, especially in the pediatric population. We examined NET formation in vitro in PMNs isolated from 24 patients who had undergone BMT for 13 different clinical indications. For these 24 study participants, the median age was 7 years. For 6 of the 24 patients, we examined NET formation by PMNs isolated from serial, peripheral blood samples drawn at three different clinical time points: pre-BMT, pre-engraftment, and post-engraftment. We found decreased NET formation by PMNs isolated from patients prior to BMT and during the pre-engraftment and post-engraftment phases, with decreased NET formation compared with healthy control PMNs detected even out to 199 days after their BMT. This decrease in NET formation after BMT did not result from neutrophil developmental immaturity as we demonstrated that >80% of the PMNs tested using flow cytometry expressed both CD10 and CD16 as markers of terminal differentiation along the neutrophilic lineage. These pilot study results mandate further exploration regarding the mechanisms or factors

  7. Deficient Neutrophil Extracellular Trap Formation in Patients Undergoing Bone Marrow Transplantation

    PubMed Central

    Glenn, Jared W.; Cody, Mark J.; McManus, Meghann P.; Pulsipher, Michael A.; Schiffman, Joshua D.; Yost, Christian Con

    2016-01-01

    Overwhelming infection causes significant morbidity and mortality among patients treated with bone marrow transplantation (BMT) for primary immune deficiencies, syndromes of bone marrow failure, or cancer. The polymorphonuclear leukocyte (PMN; neutrophil) is the first responder to microbial invasion and acts within the innate immune system to contain and clear infections. PMNs contain, and possibly clear, infections in part by forming neutrophil extracellular traps (NETs). NETs are extensive lattices of extracellular DNA and decondensed chromatin decorated with antimicrobial proteins and degradative enzymes, such as histones, myeloperoxidase, and neutrophil elastase. They trap and contain microbes, including bacteria and fungi, and may directly affect extracellular microbial killing. Whether or not deficient NET formation contributes to the increased risk for overwhelming infection in patients undergoing BMT remains incompletely characterized, especially in the pediatric population. We examined NET formation in vitro in PMNs isolated from 24 patients who had undergone BMT for 13 different clinical indications. For these 24 study participants, the median age was 7 years. For 6 of the 24 patients, we examined NET formation by PMNs isolated from serial, peripheral blood samples drawn at three different clinical time points: pre-BMT, pre-engraftment, and post-engraftment. We found decreased NET formation by PMNs isolated from patients prior to BMT and during the pre-engraftment and post-engraftment phases, with decreased NET formation compared with healthy control PMNs detected even out to 199 days after their BMT. This decrease in NET formation after BMT did not result from neutrophil developmental immaturity as we demonstrated that >80% of the PMNs tested using flow cytometry expressed both CD10 and CD16 as markers of terminal differentiation along the neutrophilic lineage. These pilot study results mandate further exploration regarding the mechanisms or factors

  8. The effect of enamel matrix proteins and deproteinized bovine bone mineral on heterotopic bone formation.

    PubMed

    Donos, Nikolaos; Kostopoulos, Lambros; Tonetti, Maurizio; Karring, Thorkild; Lang, Niklaus P

    2006-08-01

    To evaluate the osteoinductive potential of deproteinized bovine bone mineral (DBBM) and an enamel matrix derivative (EMD) in the muscle of rats. Sixteen rats were used in this study. The animals were divided in three groups. Group A: a pouch was created in one of the pectoralis profundis muscles of the thorax of the rats and DBBM particles (Bio-Oss) were placed into the pouch. Healing: 60 days. Group B: a small pouch was created on both pectoralis profundis muscles at each side of the thorax midline. In one side, a mixture of EMD (Emdogain) mixed with DBBM was placed into one of the pouches, whereas in the contralateral side of the thorax the pouch was implanted with DBBM mixed with the propylene glycol alginate (PGA--carrier for enamel matrix proteins of EMD). Healing: 60 days. Group C: the same procedure as group B, but with a healing period of 120 days. Qualitative histological analysis of the results was performed. At 60 days, the histological appearance of the DBBM particles implanted alone was similar to that of the particles implanted together with EMD or PGA at both 60 and 120 days. The DBBM particles were encapsulated into a connective tissue stroma and an inflammatory infiltrate. At 120 days, the DBBM particles implanted together with EMD or PGA exhibited the presence of resorption lacunae in some cases. Intramuscular bone formation was not encountered in any group. The implantation of DBBM particles alone, combined with EMD or its carrier (PGA) failed to exhibit extraskeletal, bone-inductive properties.

  9. Osteoclast-derived exosomal miR-214-3p inhibits osteoblastic bone formation

    PubMed Central

    Li, Defang; Liu, Jin; Guo, Baosheng; Liang, Chao; Dang, Lei; Lu, Cheng; He, Xiaojuan; Cheung, Hilda Yeuk-Siu; Xu, Liang; Lu, Changwei; He, Bing; Liu, Biao; Shaikh, Atik Badshah; Li, Fangfei; Wang, Luyao; Yang, Zhijun; Au, Doris Wai-Ting; Peng, Songlin; Zhang, Zongkang; Zhang, Bao-Ting; Pan, Xiaohua; Qian, Airong; Shang, Peng; Xiao, Lianbo; Jiang, Baohong; Wong, Chris Kong-Chu; Xu, Jiake; Bian, Zhaoxiang; Liang, Zicai; Guo, De-an; Zhu, Hailong; Tan, Weihong; Lu, Aiping; Zhang, Ge

    2016-01-01

    Emerging evidence indicates that osteoclasts direct osteoblastic bone formation. MicroRNAs (miRNAs) have a crucial role in regulating osteoclast and osteoblast function. However, whether miRNAs mediate osteoclast-directed osteoblastic bone formation is mostly unknown. Here, we show that increased osteoclastic miR-214-3p associates with both elevated serum exosomal miR-214-3p and reduced bone formation in elderly women with fractures and in ovariectomized (OVX) mice. Osteoclast-specific miR-214-3p knock-in mice have elevated serum exosomal miR-214-3p and reduced bone formation that is rescued by osteoclast-targeted antagomir-214-3p treatment. We further demonstrate that osteoclast-derived exosomal miR-214-3p is transferred to osteoblasts to inhibit osteoblast activity in vitro and reduce bone formation in vivo. Moreover, osteoclast-targeted miR-214-3p inhibition promotes bone formation in ageing OVX mice. Collectively, our results suggest that osteoclast-derived exosomal miR-214-3p transfers to osteoblasts to inhibit bone formation. Inhibition of miR-214-3p in osteoclasts may be a strategy for treating skeletal disorders involving a reduction in bone formation. PMID:26947250

  10. High phosphorus intakes acutely and negatively affect Ca and bone metabolism in a dose-dependent manner in healthy young females.

    PubMed

    Kemi, Virpi E; Kärkkäinen, Merja U M; Lamberg-Allardt, Christel J E

    2006-09-01

    Ca and P are both essential nutrients for bone and are known to affect one of the most important regulators of bone metabolism, parathyroid hormone (PTH). Too ample a P intake, typical of Western diets, could be deleterious to bone through the increased PTH secretion. Few controlled dose-response studies are available on the effects of high P intake in man. We studied the short-term effects of four P doses on Ca and bone metabolism in fourteen healthy women, 20-28 years of age, who were randomized to four controlled study days; thus each study subject served as her own control. P supplement doses of 0 (placebo), 250, 750 or 1500 mg were taken, divided into three doses during the study day. The meals served were exactly the same during each study day and provided 495 mg P and 250 mg Ca. The P doses affected the serum PTH (S-PTH) in a dose-dependent manner (P=0.0005). There was a decrease in serum ionized Ca concentration only in the highest P dose (P=0.004). The marker of bone formation, bone-specific alkaline phosphatase, decreased (P=0.05) and the bone resorption marker, N-terminal telopeptide of collagen type I, increased in response to the P doses (P=0.05). This controlled dose-response study showed that P has a dose-dependent effect on S-PTH and increases PTH secretion significantly when Ca intake is low. Acutely high P intake adversely affects bone metabolism by decreasing bone formation and increasing bone resorption, as indicated by the bone metabolism markers.

  11. UK Food Standards Agency Optimal Nutrition Status Workshop: environmental factors that affect bone health throughout life.

    PubMed

    Burns, Lynn; Ashwell, Margaret; Berry, Jacqueline; Bolton-Smith, Caroline; Cassidy, Aedin; Dunnigan, Matthew; Khaw, Kay Tee; Macdonald, Helen; New, Susan; Prentice, Ann; Powell, Jonathan; Reeve, Jonathan; Robins, Simon; Teucher, Birgit

    2003-06-01

    The UK Food Standards Agency (FSA) convened a group of expert scientists to discuss and review UK FSA- and Department of Health-funded research on diet and bone health. This research focused on the lifestyle factors that are amenable to change and may significantly affect bone health and the risk of osteoporotic fracture. The potential benefits of fruits and vegetables, meat, Ca, vitamins D and K and phyto-oestrogens were presented and discussed. Other lifestyle factors were also discussed, particularly the effect of physical activity and possible gene-nutrient interactions affecting bone health.

  12. Bone-like tissue formation on a biomimetic titanium surface in an explant model of osteoconduction.

    PubMed

    Isaac, Juliane; Loty, Sabine; Hamdan, Ahmad; Kokubo, Tadashi; Kim, Hyun-Min; Berdal, Ariane; Sautier, Jean-Michel

    2009-06-01

    The clinical use of titanium in dental and orthopedic applications is limited. Over recent years, implant surfaces have undergone numerous modifications to enhance bone integration. In this study, we experimented a bioactive titanium using a simple chemical and moderate heat treatment that led to the formation of a bone-like apatite layer on its surface in simulated body fluids. We used a bone explant model to demonstrate that cells can migrate from the explants and subsequently differentiate to form a mineralized nodular structure. Furthermore, these cells expressed alkaline phosphatase, bone sialoprotein, osteocalcin and the transcription factor, Runx2. Using this model of osteoconduction, we showed that bioactive titanium bonds directly to bone, while pure titanium cannot. These findings show the importance of implant surface composition in promoting osteogenic cell differentiation and subsequent apposition of the bone matrix, allowing strong bonds to form. This model could be particularly beneficial to closely mimic bone formation adjacent to endosseous implants.

  13. Programmed administration of parathyroid hormone increases bone formation and reduces bone loss in hindlimb-unloaded ovariectomized rats

    NASA Technical Reports Server (NTRS)

    Turner, R. T.; Evans, G. L.; Cavolina, J. M.; Halloran, B.; Morey-Holton, E.

    1998-01-01

    Gonadal insufficiency and reduced mechanical usage are two important risk factors for osteoporosis. The beneficial effects of PTH therapy to reverse the estrogen deficiency-induced bone loss in the laboratory rat are well known, but the influence of mechanical usage in this response has not been established. In this study, the effects of programed administration of PTH on cancellous bone volume and turnover at the proximal tibial metaphysis were determined in hindlimb-unloaded, ovariectomized (OVX), 3-month-old Sprague-Dawley rats. PTH was administered to weight-bearing and hindlimb-unloaded OVX rats with osmotic pumps programed to deliver 20 microg human PTH (approximately 80 microg/kg x day) during a daily 1-h infusion for 7 days. Compared with sham-operated rats, OVX increased longitudinal and radial bone growth, increased indexes of cancellous bone turnover, and resulted in net resorption of cancellous bone. Hindlimb unloading of OVX rats decreased longitudinal and radial bone growth, decreased osteoblast number, increased osteoclast number, and resulted in a further decrease in cancellous bone volume compared with those in weight-bearing OVX rats. Programed administration of PTH had no effect on either radial or longitudinal bone growth in weight-bearing and hindlimb-unloaded OVX rats. PTH treatment had dramatic effects on selected cancellous bone measurements; PTH maintained cancellous bone volume in OVX weight-bearing rats and greatly reduced cancellous bone loss in OVX hindlimb-unloaded rats. In the latter animals, PTH treatment prevented the hindlimb unloading-induced reduction in trabecular thickness, but the hormone was ineffective in preventing either the increase in osteoclast number or the loss of trabecular plates. Importantly, PTH treatment increased the retention of a baseline flurochrome label, osteoblast number, and bone formation in the proximal tibial metaphysis regardless of the level of mechanical usage. These findings demonstrate that

  14. Breast Cancer Metastasis to Bone Affects Osteoblast Differentiation

    DTIC Science & Technology

    2005-05-01

    Miele, M.E., Babu, G.R., Melly, R., Beck, L.N., Kent, J., Gilman, V.R., Sosnowski, D.M., Campo , D.A., Gay, C.V., Budgeon, L.R., Christensen, N.D...a gift from Dr. Henry Donahue, Penn State Hershey Medical Center. MDA-MB-231 cells were maintained in DMEM containing 5% fetal bovine serum (FBS) and...metastasis of breast cancer to bone, J.Orthop.Sci. 5 (2000) 75-81. [15] E. Luegmayr, F. Varga , T. Frank, et al., Effects of triiodothyronine on

  15. Cadmium stimulates osteoclast-like multinucleated cell formation in mouse bone marrow cell cultures

    SciTech Connect

    Miyahara, Tatsuro; Takata, Masakazu; Miyata, Masaki; Nagai, Miyuki; Sugure, Akemi; Kozuka, Hiroshi; Kuze, Shougo )

    1991-08-01

    Most of cadmium (Cd)-treated animals have been reported to show osteoporosis-like changes in bones. This suggests that Cd may promote bone loss by a direct action on bone. It was found that Cd stimulated prostaglandin E{sub 2}(PGE{sub 2}) production in the osteoblast-like cell, MC3T3-E1. Therefore, Cd stimulates bone resorption by increasing PGE{sub 2} production. Recently, several bone marrow cell culture systems have been developed for examining the formation of osteoclast-like multinucleated cells in vitro. As osteoblasts produce PGE{sub 2} by Cd-induced cyclooxygenase and may play an important role in osteoclast formation, the present study was undertaken to clarify the possibility that Cd might stimulate osteoclast formation in a mouse bone marrow culture system.

  16. Tissue and cellular basis for impaired bone formation in aluminum-related osteomalacia in the pig.

    PubMed Central

    Sedman, A B; Alfrey, A C; Miller, N L; Goodman, W G

    1987-01-01

    Bone formation is impaired in aluminum-associated bone disease. Reductions in the number of osteoblasts or in the function of individual osteoblasts could account for this finding. Thus, quantitative bone histology and measurements of bone formation were done at three skeletal sites in piglets given aluminum (Al) parenterally, 1.5 mg/kg per d, for 8 wk (Al, n = 4) and in control animals (C, n = 4). Bone Al was 241 +/- 40 mg/kg per dry weight in Al and 1.6 +/- 0.9 in C, P less than 0.001. All Al-treated animals developed osteomalacia with increases in osteoid seam width, osteoid volume, and mineralization lag time at each skeletal site, P less than 0.05 vs. C for all values. Mineralized bone formation at the tissue level was lower in Al than in C, P less than 0.05 for each skeletal site, due to reductions in active bone forming surface. Bone formation at the cellular level was similar in each group, however, and total osteoid production by osteoblasts did not differ in C and Al. Aluminum impairs the formation of mineralized bone in vivo by decreasing the number of active osteoblasts, and this change can be distinguished from the effect of aluminum to inhibit, either directly or indirectly, the calcification of osteoid. PMID:3793934

  17. A bisphosphonate that does not affect osteoclasts prevents osteoblast and osteocyte apoptosis and the loss of bone strength induced by glucocorticoids in mice.

    PubMed

    Plotkin, L I; Bivi, Nicoletta; Bellido, T

    2011-07-01

    Although a major effect of bisphosphonates on bone is inhibition of resorption resulting from their ability to interfere with osteoclast function, these agents also prevent osteoblast and osteocyte apoptosis in vitro and in vivo. However, the contribution of the latter property to the overall beneficial effects of the drugs on bone remains unknown. We compared herein the action on glucocorticoid-induced bone disease of the classical bisphosphonate alendronate with that of IG9402, a bisphosphonate analog that preserves osteoblast and osteocyte viability but does not induce osteoclast apoptosis in vitro. The bisphosphonates were injected daily (2.3 μmol/kg) to 5-month-old Swiss Webster mice (6-11 per group), starting 3 days before implantation of pellets releasing the glucocorticoid prednisolone (2.1 mg/kg/day). IG9402 did not affect levels of circulating C-telopeptide or osteocalcin, markers of resorption and formation, respectively, nor did it decrease mRNA levels of osteocalcin or collagen 1a1 in bone. On the other hand, alendronate decreased all these parameters. Moreover, IG9402 did not reduce cancellous mineralizing surface, mineral apposition rate, or bone formation rate, whereas alendronate induced a decrease in each of these bone formation measures. These findings demonstrate that, in contrast to alendronate, IG9402 does not inhibit bone turnover. Both alendronate and IG9402, on the other hand, activated survival kinase signaling in vivo, as evidenced by induction of ERK phosphorylation in bone. Furthermore, both bisphosphonates prevented the increase in osteoblast and osteocyte apoptosis as well as the decrease in vertebral bone mass and strength induced by glucocorticoids. We conclude that a bisphosphonate that does not affect osteoclasts prevents osteoblast and osteocyte apoptosis and the loss of bone strength induced by glucocorticoids in mice.

  18. Effect of Alendronate on Bone Formation during Tooth Extraction Wound Healing.

    PubMed

    Tanoue, R; Koi, K; Yamashita, J

    2015-09-01

    Alendronate (ALN) is an antiresorptive agent widely used for the treatment of osteoporosis. Its suppressive effect on osteoclasts has been extensively studied. However, the effect of ALN on bone formation is not as clear as its effect on resorption. The objective was to determine the effect of short-term ALN on bone formation and tooth extraction wound healing. Molar tooth extractions were performed in mice. ALN, parathyroid hormone (PTH), or saline (vehicle control) was administered. PTH was used as the bone anabolic control. Mice were euthanized at 3, 5, 7, 10, and 21 d after extractions. Hard tissue healing was determined histomorphometrically. Neutrophils and lymphatic and blood vessels were quantified to evaluate soft tissue healing. Gene expression in the wounds was assessed at the RNA level. Furthermore, the vossicle bone transplant system was used to verify findings from extraction wound analysis. Alkaline phosphatase (ALP) was visualized in the vossicles to assess osteoblast activity. ALN exhibited no negative effect on bone formation. In intact tibiae, ALN increased bone mass significantly more than PTH did. Consistently, significantly elevated osteoblast numbers were noted. In the extraction sockets, bone fill in the ALN-treated mice was equivalent to the control. Genes associated with bone morphogenetic protein signaling, such as bmp2, nog, and dlx5, were activated in the extraction wounds of the ALN-treated animals. Bone formation in vossicles was significantly enhanced in the ALN versus PTH group. In agreement with this, ALN upregulated ALP activity considerably in vossicles. Neutrophil aggregation and suppressed lymphangiogenesis were evident in the soft tissue at 21 d after extraction, although gross healing of extraction wounds was uneventful. Bone formation was not impeded by short-term ALN treatment. Rather, short-term ALN treatment enhanced bone formation. ALN did not alter bone fill in extraction sockets.

  19. Effect of Alendronate on Bone Formation during Tooth Extraction Wound Healing

    PubMed Central

    Tanoue, R.; Koi, K.

    2015-01-01

    Alendronate (ALN) is an antiresorptive agent widely used for the treatment of osteoporosis. Its suppressive effect on osteoclasts has been extensively studied. However, the effect of ALN on bone formation is not as clear as its effect on resorption. The objective was to determine the effect of short-term ALN on bone formation and tooth extraction wound healing. Molar tooth extractions were performed in mice. ALN, parathyroid hormone (PTH), or saline (vehicle control) was administered. PTH was used as the bone anabolic control. Mice were euthanized at 3, 5, 7, 10, and 21 d after extractions. Hard tissue healing was determined histomorphometrically. Neutrophils and lymphatic and blood vessels were quantified to evaluate soft tissue healing. Gene expression in the wounds was assessed at the RNA level. Furthermore, the vossicle bone transplant system was used to verify findings from extraction wound analysis. Alkaline phosphatase (ALP) was visualized in the vossicles to assess osteoblast activity. ALN exhibited no negative effect on bone formation. In intact tibiae, ALN increased bone mass significantly more than PTH did. Consistently, significantly elevated osteoblast numbers were noted. In the extraction sockets, bone fill in the ALN-treated mice was equivalent to the control. Genes associated with bone morphogenetic protein signaling, such as bmp2, nog, and dlx5, were activated in the extraction wounds of the ALN-treated animals. Bone formation in vossicles was significantly enhanced in the ALN versus PTH group. In agreement with this, ALN upregulated ALP activity considerably in vossicles. Neutrophil aggregation and suppressed lymphangiogenesis were evident in the soft tissue at 21 d after extraction, although gross healing of extraction wounds was uneventful. Bone formation was not impeded by short-term ALN treatment. Rather, short-term ALN treatment enhanced bone formation. ALN did not alter bone fill in extraction sockets. PMID:26124220

  20. Bone marrow-derived osteoblast progenitor cells in circulating blood contribute to ectopic bone formation in mice

    SciTech Connect

    Otsuru, Satoru; Tamai, Katsuto . E-mail: tamai@gts.med.osaka-u.ac.jp; Yamazaki, Takehiko; Yoshikawa, Hideki; Kaneda, Yasufumi

    2007-03-09

    Recent studies have suggested the existence of osteoblastic cells in the circulation, but the origin and role of these cells in vivo are not clear. Here, we examined how these cells contribute to osteogenesis in a bone morphogenetic protein (BMP)-induced model of ectopic bone formation. Following lethal dose-irradiation and subsequent green fluorescent protein-transgenic bone marrow cell-transplantation (GFP-BMT) in mice, a BMP-2-containing collagen pellet was implanted into muscle. Three weeks later, a significant number of GFP-positive osteoblastic cells were present in the newly generated ectopic bone. Moreover, peripheral blood mononuclear cells (PBMNCs) from the BMP-2-implanted mouse were then shown to include osteoblast progenitor cells (OPCs) in culture. Passive transfer of the PBMNCs isolated from the BMP-2-implanted GFP-mouse to the BMP-2-implanted nude mouse led to GFP-positive osteoblast accumulation in the ectopic bone. These data provide new insight into the mechanism of ectopic bone formation involving bone marrow-derived OPCs in circulating blood.

  1. Predicting the external formation of callus tissues in oblique bone fractures: idealised and clinical case studies.

    PubMed

    Comiskey, D; MacDonald, B J; McCartney, W T; Synnott, K; O'Byrne, J

    2013-11-01

    It is proposed that the external asymmetric formation of callus tissues that forms naturally about an oblique bone fracture can be predicted computationally. We present an analysis of callus formation for two cases of bone fracture healing: idealised and subject-specific oblique bone fractures. Plane strain finite element (FE) models of the oblique fractures were generated to calculate the compressive strain field experienced by the immature callus tissues due to interfragmentary motion. The external formations of the calluses were phenomenologically simulated using an optimisation style algorithm that iteratively removes tissue that experiences low strains from a large domain. The resultant simulated spatial formation of the healing tissues for the two bone fracture cases showed that the calluses tended to form at an angle equivalent to the angle of the oblique fracture line. The computational results qualitatively correlated with the callus formations found in vivo. Consequently, the proposed methods show potential as a means of predicting callus formation in pre-clinical testing.

  2. Vitamin D: more than just affecting calcium and bone.

    PubMed

    Staud, Roland

    2005-10-01

    Vitamin D is a fat-soluble steroid that is essential for maintaining normal calcium metabolism. In vitamin D deficiency, calcium absorption is insufficient and cannot satisfy the body's needs. Consequently, parathyroid hormone production increases and calcium is mobilized from bones and reabsorbed in the kidneys to maintain normal serum calcium levels--a condition defined as secondary hyperparathyroidism. Most organs, including the gut, brain, heart, pancreas, skin, kidneys, and immune system have receptors for 1,25 (OH)vitamin D. Furthermore, all of these organs have the capacity to synthesize 1,25 (OH)vitamin D from vitamin D. Extensive research suggests that vitamin D deficiency is common and represents a global health problem. Clinical consequences related to low vitamin D levels include not only osteomalacia, osteoporosis, and rickets, but also neuro-muscular dysfunction and fractures. Falls related to neuromuscular dysfunction lead to 40% of all nursing home admissions and are the largest single cause of injury-related deaths in elderly people. About one-third of all persons 65 and older fall at least once a year, resulting in more than 1.5 million emergency room treatments and more than 300,000 hospitalizations. Falls cause more than 11,000 deaths per year, most of them in elderly patients (> or = 75 years) who suffer hip fractures. It is well established that vitamin D deficiency not only has serious consequences for bone health, but also for other organ systems. Previous studies have shown that vitamin D supplementation reduces the number of fractures and directly improves neuromuscular function, thus helping to prevent falls and subsequent fractures. In addition, vitamin D appears to have other important functions as a regulator of cell differentiation and cell growth.

  3. Impact of skeletal unloading on bone formation: Role of systemic and local factors

    NASA Astrophysics Data System (ADS)

    Bikle, Daniel D.; Halloran, Bernard P.; Morey-Holton, Emily

    We have developed a model of skeletal unloading using growing rats whose hindlimbs are unweighted by tail suspension. The bones in the hindlimbs undergo a transient cessation of bone growth; when reloaded bone formation is accelerated until bone mass is restored. These changes do not occur in the normally loaded bones of the forelimbs. Associated with the fall in bone formation is a fall in 1,25(OH) 2D 3 production and osteocalcin levels. In contrast, no changes in parathyroid hormone, calcium, or corticosterone levels are seen. To examine the role of locally produced growth factors, we have measured the mRNA and protein levels of insulin like growth factor-1 (IGF-1) in bone during tail suspension. Surprisingly, both the mRNA and protein levels of IGF-1 increase during tail suspension as bone formation is reduced. Furthermore, the bones in the hindlimbs of the suspended animals develop a resistance to the growth promoting effects of both growth hormone and IGF-1 when given parenterally. Thus, the cessation of bone growth with skeletal unloading is apparently associated with a resistance to rather than failure to produce local growth factors. The cause of this resistance remains under active investigation.

  4. Short-term aluminum administration in the rat: reductions in bone formation without osteomalacia

    SciTech Connect

    Goodman, W.G.

    1984-05-01

    Aluminum may be a pathogenic factor in dialysis-associated osteomalacia. To study the early effects of Al on bone, cortical bone growth was measured in pair-fed rats given Al and control rats over two consecutive intervals of 28 (period I) and 16 (period II) days, respectively, using tetracycline labeling of bone. Al (2 mg elemental Al per rat) was administered intraperitoneally for 5 days each week, except for the first week of study, when an incremental dose of Al was given. Control rats received saline vehicle only. For the entire 44-day study, bone and matrix formation were reduced from control values in rats given Al. Although bone and matrix formation remained at control levels during period I in rats given Al, both measurements decreased from control values during period II. During Al exposure, bone and matrix apposition at the periosteum were reduced from control levels in period II, but not in period I. Neither osteoid width nor mineralization front width increased from control values in rats given Al. These findings indicate that Al reduces bone and matrix formation early in the course of Al exposure and prior to the development of histologic osteomalacia. Rather than acting as an inhibitor of mineralization, the early effect of Al on bone is the suppression of matrix synthesis. Our results suggest that the state of low bone formation seen in dialysis-associated osteomalacia may be the consequence of a direct toxic effect of Al on the cellular activity of osteoblasts. 29 references, 3 tables.

  5. Directly auto-transplanted mesenchymal stem cells induce bone formation in a ceramic bone substitute in an ectopic sheep model.

    PubMed

    Boos, Anja M; Loew, Johanna S; Deschler, Gloria; Arkudas, Andreas; Bleiziffer, Oliver; Gulle, Heinz; Dragu, Adrian; Kneser, Ulrich; Horch, Raymund E; Beier, Justus P

    2011-06-01

    Bone tissue engineering approaches increasingly focus on the use of mesenchymal stem cells (MSC). In most animal transplantation models MSC are isolated and expanded before auto cell transplantation which might be critical for clinical application in the future. Hence this study compares the potential of directly auto-transplanted versus in vitro expanded MSC with or without bone morphogenetic protein-2 (BMP-2) to induce bone formation in a large volume ceramic bone substitute in the sheep model. MSC were isolated from bone marrow aspirates and directly auto-transplanted or expanded in vitro and characterized using fluorescence activated cell sorting (FACS) and RT-PCR analysis before subcutaneous implantation in combination with BMP-2 and β-tricalcium phosphate/hydroxyapatite (β-TCP/HA) granules. Constructs were explanted after 1 to 12 weeks followed by histological and RT-PCR evaluation. Sheep MSC were CD29(+), CD44(+) and CD166(+) after selection by Ficoll gradient centrifugation, while directly auto-transplanted MSC-populations expressed CD29 and CD166 at lower levels. Both, directly auto-transplanted and expanded MSC, were constantly proliferating and had a decreasing apoptosis over time in vivo. Directly auto-transplanted MSC led to de novo bone formation in a heterotopic sheep model using a β-TCP/HA matrix comparable to the application of 60 μg/ml BMP-2 only or implantation of expanded MSC. Bone matrix proteins were up-regulated in constructs following direct auto-transplantation and in expanded MSC as well as in BMP-2 constructs. Up-regulation was detected using immunohistology methods and RT-PCR. Dense vascularization was demonstrated by CD31 immunohistology staining in all three groups. Ectopic bone could be generated using directly auto-transplanted or expanded MSC with β-TCP/HA granules alone. Hence BMP-2 stimulation might become dispensable in the future, thus providing an attractive, clinically feasible approach to bone tissue engineering.

  6. Recombinant human bone morphogenetic protein-2 suspended in fibrin glue enhances bone formation during distraction osteogenesis in rabbits

    PubMed Central

    Li, Yunfeng; Li, Rui; Hu, Jing; Song, Donghui; Jiang, Xiaowen

    2016-01-01

    Introduction Bone morphogenetic protein-2 (BMP-2) has high potential for bone formation, but its in vivo effects are unpredictable due to the short life time. This study was designed to evaluate the effects of recombinant human (rh) BMP-2 suspended in fibrin on bone formation during distraction osteogenesis (DO) in rabbits. Material and methods The in vitro release kinetics of rhBMP-2 suspended in fibrin was tested using an enzyme-linked immunosorbent assay. Unilateral tibial lengthening for 10 mm was achieved in 48 rabbits. At the completion of osteodistraction, vehicle, fibrin, rhBMP-2 or rhBMP-2 suspended in fibrin (rhBMP-2 + fibrin) was injected into the center of the lengthened gap, with 12 animals in each group. Eight weeks later, the distracted callus was examined by histology, micro-CT and biomechanical testing. Radiographs of the distracted tibiae were taken at both 4 and 8 weeks after drug treatment. Results It was found that fibrin prolonged the life span of rhBMP-2 in vitro with sustained release during 17 days. The rhBMP-2 + fibrin treated animals showed the best results in bone mineral density, bone volume fraction, cortical bone thickness by micro-CT evaluation and mechanical properties by the three-point bending test when compared to the other groups (p < 0.05). In histological images, rhBMP-2 + fibrin treatment showed increased callus formation and better gap bridging compared to the other groups. Conclusions The results of this study suggest that fibrin holds promise to be a good carrier of rhBMP-2, and rhBMP-2 suspended in fibrin showed a stronger promoting effect on bone formation during DO in rabbits. PMID:27279839

  7. Bone regenerate formation in cortical bone during distraction lengthening. An experimental study.

    PubMed

    Delloye, C; Delefortrie, G; Coutelier, L; Vincent, A

    1990-01-01

    The aim of this study was to delineate the pattern of bone regeneration from cortical bone segments during distraction lengthening. The lengthening procedure was applied for various periods through the Ilizarov system on the forearms of mature dogs. Bone was sectioned either by corticotomy, preserving the nutrient artery integrity, or by osteotomy. When an osteotomy was performed, the marrow cavity was in some cases plugged with either resorbable bone wax or nonresorbable material. Under distraction, both periosteal and medullary callus on either side of the gap gave rise to new bone trabeculae. The trabeculae on either side were oriented along the direction of distraction and progressively approached one another. This striated callus emerging from both sides was the most characteristic pattern of bone regeneration subsequent to distraction lengthening. Fusion was achieved approximately four weeks after the end of the lengthening period. Most of the new bone was formed by membranous ossification; some cartilaginous nodules developed. Corticalization of the bone trabeculae that had begun at three months was not fully achieved at five months after the lengthening period. There were no differences found in the pattern of bone healing and the amount of newly formed bone after corticotomy or osteotomy with or without resorbable bone wax plugging.

  8. Insertion site and sealing technique affect residual hearing and tissue formation after cochlear implantation.

    PubMed

    Burghard, Alice; Lenarz, Thomas; Kral, Andrej; Paasche, Gerrit

    2014-06-01

    Tissue formation around the electrode array of a cochlear implant has been suggested to influence preservation of residual hearing as well as electrical hearing performance of implanted subjects. Further, inhomogeneity in the electrical properties of the scala tympani shape the electrical field and affect current spread. Intracochlear trauma due to electrode insertion and the insertion site itself are commonly seen as triggers for the tissue formation. The present study investigates whether the insertion site, round window membrane (RWM) vs. cochleostomy (CS), or the sealing material, no seal vs. muscle graft vs. carboxylate cement, have an influence on the amount of fibrous tissue and/or new bone formation after CI implantation in the guinea pig. Hearing thresholds were determined by auditory brainstem response (ABR) measurements prior to implantation and after 28 days. The amount of tissue formation was quantified by evaluation of microscopic images obtained by a grinding/polishing procedure to keep the CI in place during histological processing. An insertion via the round window membrane resulted after 28 days in less tissue formation in the no seal and muscle seal condition compared to the cochleostomy approach. Between these two sealing techniques there was no difference. Sealing the cochlea with carboxylate cement resulted always in a strong new bone formation and almost total loss of residual hearing. The amount of tissue formation and the hearing loss correlated at 1-8 kHz. Consequently, the use of carboxylate cement as a sealing material in cochlear implantation should be avoided even in animal studies, whereas sealing the insertion site with a muscle graft did not induce an additional tissue growth compared to omitting a seal. For hearing preservation the round window approach should be used.

  9. Principles of bone formation driven by biophysical forces in craniofacial surgery.

    PubMed

    Meyer, U; Kruse-Lösler, B; Wiesmann, H P

    2006-08-01

    Biophysical forces, particularly mechanical loading and electromagnetic signals, are important regulators of bone formation. Indeed, the regenerative capacity of bony tissue is largely the result of the bone's capacity to recognise the functional environment required for the emergence and maintenance of a structurally intact bone. Biophysical methods of stimulation have therefore been introduced and have proved successful in clinical practice with craniofacial bones. Distraction osteogenesis, application of ultrasound, calculated transfer of stresses, and exposure to an electromagnetic field are some examples of biophysically driven approaches to influencing bone formation. The purpose of this review is to provide an insight into cellular and tissue models that are used to study the effects of biophysical stimuli on bone.

  10. The circadian modulation of leptin-controlled bone formation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mice with circadian gene Period and Cryptochrome mutations develop high bone mass early in life. Such a phenotype is accompanied by an increase in osteoblast numbers in mutant bone and cannot be corrected by leptin intracerebroventricular infusion. Thus, the molecular clock plays a key role in lepti...

  11. Growth Hormone Regulates the Balance Between Bone Formation and Bone Marrow Adiposity

    PubMed Central

    Menagh, Philip J; Turner, Russell T; Jump, Donald B; Wong, Carmen P; Lowry, Malcolm B; Yakar, Shoshana; Rosen, Clifford J; Iwaniec, Urszula T

    2010-01-01

    Cancellous bone decreases and bone marrow fat content increases with age. Osteoblasts and adipocytes are derived from a common precursor, and growth hormone (GH), a key hormone in integration of energy metabolism, regulates the differentiation and function of both cell lineages. Since an age-related decline in GH is associated with bone loss, we investigated the relationship between GH and bone marrow adiposity in hypophysectomized (HYPOX) rats and in mice with defects in GH signaling. HYPOX dramatically reduced body weight gain, bone growth and mineralizing perimeter, serum insulin-like growth factor 1 (IGF-1) levels, and mRNA levels for IGF-1 in liver and bone. Despite reduced body mass and adipocyte precursor pool size, HYPOX resulted in a dramatic increase in bone lipid levels, as reflected by increased bone marrow adiposity and bone triglyceride and cholesterol content. GH replacement normalized bone marrow adiposity and precursor pool size, as well as mineralizing perimeter in HYPOX rats. In contrast, 17β -estradiol, IGF-1, thyroxine, and cortisone were ineffective. Parathyroid hormone (PTH) reversed the inhibitory effects of HYPOX on mineralizing perimeter but had no effect on adiposity. Finally, bone marrow adiposity was increased in mice deficient in GH and IGF-1 but not in mice deficient in serum IGF-1. Taken together, our findings indicate that the reciprocal changes in bone and fat mass in GH signaling-deficient rodents are not directly coupled with one another. Rather, GH enhances adipocyte as well as osteoblast precursor pool size. However, GH increases osteoblast differentiation while suppressing bone marrow lipid accumulation. © 2010 American Society for Bone and Mineral Research PMID:19821771

  12. μCT-based, in vivo dynamic bone histomorphometry allows 3D evaluation of the early responses of bone resorption and formation to PTH and alendronate combination therapy.

    PubMed

    de Bakker, Chantal M J; Altman, Allison R; Tseng, Wei-Ju; Tribble, Mary Beth; Li, Connie; Chandra, Abhishek; Qin, Ling; Liu, X Sherry

    2015-04-01

    Current osteoporosis treatments improve bone mass by increasing net bone formation: anti-resorptive drugs such as bisphosphonates block osteoclast activity, while anabolic agents such as parathyroid hormone (PTH) increase bone remodeling, with a greater effect on formation. Although these drugs are widely used, their role in modulating formation and resorption is not fully understood, due in part to technical limitations in the ability to longitudinally assess bone remodeling. Importantly, it is not known whether or not PTH-induced bone formation is independent of resorption, resulting in controversy over the effectiveness of combination therapies that use both PTH and an anti-resorptive. In this study, we developed a μCT-based, in vivo dynamic bone histomorphometry technique for rat tibiae, and applied this method to longitudinally track changes in bone resorption and formation as a result of treatment with alendronate (ALN), PTH, or combination therapy of both PTH and ALN (PTH+ALN). Correlations between our μCT-based measures of bone formation and measures of bone formation based on calcein-labeled histology (r=0.72-0.83) confirm the accuracy of this method. Bone remodeling parameters measured through μCT-based in vivo dynamic bone histomorphometry indicate an increased rate of bone formation in rats treated with PTH and PTH+ALN, together with a decrease in bone resorption measures in rats treated with ALN and PTH+ALN. These results were further supported by traditional histology-based measurements, suggesting that PTH was able to induce bone formation while bone resorption was suppressed.

  13. The Effect of Skeletal Unloading on Bone Formation: Role of IGF-I

    NASA Technical Reports Server (NTRS)

    Bikle, D. D.; Kostenuik, P.; Holton, E. M.; Halloran, B. P.

    1999-01-01

    The best documented change in bone during space flight is the near cessation of bone formation. Space flight leads to a decrease in osteoblast number and activity, likely the result of altered differentiation of osteoblast precursors. The net result of these space flight induced changes is weaker bone. To understand the mechanism for these changes poses a challenge. Space flight studies must overcome enormous technical problems, and are necessarily limited in size and frequency. Therefore, ground based models have been developed to evaluate the effects of skeletal unloading. The hindlimb elevation (tail suspension) model simulates space flight better than other models because it reproduces the fluid shifts seen in space travel, is reversible, and is well tolerated by the animals with minimal evidence of stress as indicated by continued weight gain and normal levels and circadian rhythms of corticosterone. This is the model we have used for our experiments. Skeletal unloading by the hindlimb elevation method simulates a number of features of space flight in that bone formation, mineralization, and maturation are inhibited, osteoblast number is decreased, serum and skeletal osteocalcin levels fall, the ash content of bone decreases, and bone strength diminishes. We and others have shown that when osteoblasts or osteoprogenitor cells from the bones of the unloaded limbs are cultured in vitro they proliferate and differentiate more slowly, suggesting that skeletal unloading causes a persistent change in cell function which can be assessed in vitro. In contrast to the unweighted bones of the hindlimbs, no significant change in bone mass or bone formation is observed in the humeri, mandible, and cervical vertebrae during hindlimb elevation. The lack of effect of hindlimb elevation on bones like the humeri, mandible, and cervical vertebrae which are not unloaded by this procedure suggests that local factors rather than systemic effects dominate the response of bone to

  14. TGF-β and BMP signaling in osteoblast, skeletal development, and bone formation, homeostasis and disease

    PubMed Central

    Wu, Mengrui; Chen, Guiqian; Li, Yi-Ping

    2016-01-01

    Transforming growth factor-beta (TGF-β) and bone morphogenic protein (BMP) signaling has fundamental roles in both embryonic skeletal development and postnatal bone homeostasis. TGF-βs and BMPs, acting on a tetrameric receptor complex, transduce signals to both the canonical Smad-dependent signaling pathway (that is, TGF-β/BMP ligands, receptors, and Smads) and the non-canonical-Smad-independent signaling pathway (that is, p38 mitogen-activated protein kinase/p38 MAPK) to regulate mesenchymal stem cell differentiation during skeletal development, bone formation and bone homeostasis. Both the Smad and p38 MAPK signaling pathways converge at transcription factors, for example, Runx2 to promote osteoblast differentiation and chondrocyte differentiation from mesenchymal precursor cells. TGF-β and BMP signaling is controlled by multiple factors, including the ubiquitin–proteasome system, epigenetic factors, and microRNA. Dysregulated TGF-β and BMP signaling result in a number of bone disorders in humans. Knockout or mutation of TGF-β and BMP signaling-related genes in mice leads to bone abnormalities of varying severity, which enable a better understanding of TGF-β/BMP signaling in bone and the signaling networks underlying osteoblast differentiation and bone formation. There is also crosstalk between TGF-β/BMP signaling and several critical cytokines’ signaling pathways (for example, Wnt, Hedgehog, Notch, PTHrP, and FGF) to coordinate osteogenesis, skeletal development, and bone homeostasis. This review summarizes the recent advances in our understanding of TGF-β/BMP signaling in osteoblast differentiation, chondrocyte differentiation, skeletal development, cartilage formation, bone formation, bone homeostasis, and related human bone diseases caused by the disruption of TGF-β/BMP signaling. PMID:27563484

  15. Osterix/Sp7 limits cranial bone initiation sites and is required for formation of sutures.

    PubMed

    Kague, Erika; Roy, Paula; Asselin, Garrett; Hu, Gui; Simonet, Jacqueline; Stanley, Alexandra; Albertson, Craig; Fisher, Shannon

    2016-05-15

    During growth, individual skull bones overlap at sutures, where osteoblast differentiation and bone deposition occur. Mutations causing skull malformations have revealed some required genes, but many aspects of suture regulation remain poorly understood. We describe a zebrafish mutation in osterix/sp7, which causes a generalized delay in osteoblast maturation. While most of the skeleton is patterned normally, mutants have specific defects in the anterior skull and upper jaw, and the top of the skull comprises a random mosaic of bones derived from individual initiation sites. Osteoblasts at the edges of the bones are highly proliferative and fail to differentiate, consistent with global changes in gene expression. We propose that signals from the bone itself are required for orderly recruitment of precursor cells and growth along the edges. The delay in bone maturation caused by loss of Sp7 leads to unregulated bone formation, revealing a new mechanism for patterning the skull and sutures.

  16. Joint loading modality: its application to bone formation and fracture healing.

    PubMed

    Zhang, P; Malacinski, G M; Yokota, H

    2008-07-01

    Sports-related injuries such as impact and stress fractures often require a rehabilitation programme to stimulate bone formation and accelerate fracture healing. This review introduces a recently developed joint loading modality and evaluates its potential applications to bone formation and fracture healing in post-injury rehabilitation. Bone is a dynamic tissue whose structure is constantly altered in response to its mechanical environments. Indeed, many loading modalities can influence the bone remodelling process. The joint loading modality is, however, able to enhance anabolic responses and accelerate wound healing without inducing significant in situ strain at the site of bone formation or fracture healing. This review highlights the unique features of this loading modality and discusses its potential underlying mechanisms as well as possible clinical applications.

  17. Fibulin-1 is required for bone formation and Bmp-2-mediated induction of Osterix.

    PubMed

    Cooley, Marion A; Harikrishnan, Keerthi; Oppel, James A; Miler, Sloan F; Barth, Jeremy L; Haycraft, Courtney J; Reddy, Sakamuri V; Scott Argraves, W

    2014-12-01

    The extracellular matrix protein Fibulin-1 (Fbln1) has been shown to be involved in numerous processes including cardiovascular and lung development. Here we have examined the role of Fbln1 in bone formation. Alizarin red staining of skulls from Fbln1-deficient mice showed reduced mineralization of both membranous and endochondral bones. MicroCT (μCT) analysis of the calvarial bones (i.e., frontal, parietal and interparietal bones collectively) indicated that bone volume in Fbln1 nulls at neonatal stage P0 were reduced by 22% (p=0.015). Similarly, Fbln1 null frontal bones showed a 16% (p=0.035) decrease in bone volume, with a reduction in the interfrontal bone, and a discontinuity in the leading edge of the frontal bone. To determine whether Fbln1 played a role in osteoblast differentiation during bone formation, qPCR was used to measure the effects of Fbln1 deficiency on the expression of Osterix (Osx), a transcription factor essential for osteoblast differentiation. This analysis demonstrated that Osx mRNA was significantly reduced in Fbln1-deficient calvarial bones at developmental stages E16.5 (p=0.049) and E17.5 (p=0.022). Furthermore, the ability of Bmp-2 to induce Osx expression was significantly diminished in Fbln1-deficient mouse embryo fibroblasts. Together, these findings indicate that Fbln1 is a new positive modulator of the formation of membranous bone and endochondral bone in the skull, acting as a positive regulator of Bmp signaling.

  18. Fibulin-1 is required for bone formation and Bmp-2-mediated induction of Osterix

    PubMed Central

    Cooley, Marion A.; Harikrishnan, Keerthi; Oppel, James A.; Miler, Sloan F.; Barth, Jeremy L.; Haycraft, Courtney J.; Reddy, Sakamuri V.; Argraves, W. Scott

    2015-01-01

    The extracellular matrix protein Fibulin-1 (Fbln1) has been shown to be involved in numerous processes including cardiovascular and lung development. Here we have examined the role of Fbln1 in bone formation. Alizarin red staining of skulls from Fbln1 deficient mice showed reduced mineralization of both membranous and endochondral bones. Micro CT (μCT) analysis of the calvarial bones (i.e., frontal, parietal and interparietal bones collectively) indicated that bone volume in Fbln1 nulls at neonatal stage P0 were reduced by 22% (p = 0.015). Similarly, Fbln1 null frontal bones showed a 16% (p = 0.035) decrease in bone volume, with a reduction in the interfrontal bone, and a discontinuity in the leading edge of the frontal bone. To determine whether Fbln1 played a role in osteoblast differentiation during bone formation, qPCR was used to measure the effects of Fbln1 deficiency on the expression of Osterix (Osx), a transcription factor essential for osteoblast differentiation. This analysis demonstrated that Osx mRNA was significantly reduced in Fbln1-deficient calvarial bones at developmental stages E16.5 (p = 0.049) and E17.5 (p = 0.022). Furthermore, the ability of BMP-2 to induce Osx expression was significantly diminished in Fbln1-deficient mouse embryo fibroblasts. Together, these findings indicate that Fbln1 is a new positive modulator of the formation of membranous bone and endochondral bone in the skull, acting as a positive regulator of BMP signaling. PMID:25201465

  19. Increased bone formation in a rabbit long-bone defect model after single local and single systemic application of erythropoietin.

    PubMed

    Omlor, Georg W; Kleinschmidt, Kerstin; Gantz, Simone; Speicher, Anja; Guehring, Thorsten; Richter, Wiltrud

    2016-08-01

    Background and purpose - Delayed bone healing with non-union is a common problem. Further options to increase bone healing together with surgery are needed. We therefore evaluated a 1-dose single application of erythropoietin (EPO), applied either locally to the defect or systemically during surgery, in a critical-size rabbit long-bone defect. Material and methods - 19 New Zealand White rabbits received a 15-mm defect in the radius diaphysis. An absorbable gelatin sponge was soaked with saline (control group and systemic treatment group) or EPO (local treatment group) and implanted into the gap. The systemic treatment group received EPO subcutaneously. In vivo micro-CT analysis was performed 4, 8, and 12 weeks postoperatively. Vascularization was evaluated histologically. Results - Semiquantitative histomorphometric and radiological evaluation showed increased bone formation (2.3- to 2.5-fold) in both treatment groups after 12 weeks compared to the controls. Quantitative determination of bone volume and tissue volume showed superior bone healing after EPO treatment at all follow-up time points, with the highest values after 12 weeks in locally treated animals (3.0- to 3.4-fold). More vascularization was found in both EPO treatment groups. Interpretation - Initial single dosing with EPO was sufficient to increase bone healing substantially after 12 weeks of follow-up. Local application inside the defect was most effective, and it can be administered directly during surgery. Apart from effects on ossification, systemic and local EPO treatment leads to increased callus vascularization.

  20. Increased bone formation in a rabbit long-bone defect model after single local and single systemic application of erythropoietin

    PubMed Central

    Omlor, Georg W; Kleinschmidt, Kerstin; Gantz, Simone; Speicher, Anja; Guehring, Thorsten; Richter, Wiltrud

    2016-01-01

    Background and purpose Delayed bone healing with non-union is a common problem. Further options to increase bone healing together with surgery are needed. We therefore evaluated a 1-dose single application of erythropoietin (EPO), applied either locally to the defect or systemically during surgery, in a critical-size rabbit long-bone defect. Material and methods 19 New Zealand White rabbits received a 15-mm defect in the radius diaphysis. An absorbable gelatin sponge was soaked with saline (control group and systemic treatment group) or EPO (local treatment group) and implanted into the gap. The systemic treatment group received EPO subcutaneously. In vivo micro-CT analysis was performed 4, 8, and 12 weeks postoperatively. Vascularization was evaluated histologically. Results Semiquantitative histomorphometric and radiological evaluation showed increased bone formation (2.3- to 2.5-fold) in both treatment groups after 12 weeks compared to the controls. Quantitative determination of bone volume and tissue volume showed superior bone healing after EPO treatment at all follow-up time points, with the highest values after 12 weeks in locally treated animals (3.0- to 3.4-fold). More vascularization was found in both EPO treatment groups. Interpretation Initial single dosing with EPO was sufficient to increase bone healing substantially after 12 weeks of follow-up. Local application inside the defect was most effective, and it can be administered directly during surgery. Apart from effects on ossification, systemic and local EPO treatment leads to increased callus vascularization. PMID:27348783

  1. Young Coconut Juice Supplementation Results in Greater Bone Mass and Bone Formation Indices in Ovariectomized Rats: A Preliminary Study.

    PubMed

    Morii, Yuko; Matsushita, Hiroshi; Minami, Akira; Kanazawa, Hiroaki; Suzuki, Takashi; Subhadhirasakul, Sanan; Watanabe, Kazushi; Wakatsuki, Akihiko

    2015-12-01

    Young coconut juice (Cocos nucifera Linn.) (YCJ) has traditionally been consumed to alleviate symptoms associated with menopause by women in Southeast Asia. The aim of the present study was to determine the effects of YCJ on bone metabolism in ovariectomized rats. Female 10-week-old Wistar rats were randomly assigned to the following 4 groups: Baseline, Sham, Ovx, and Ovx + YCJ (n = 10 rats per group). Rats in the Baseline group were sacrificed immediately, and those in the other groups were subjected to either sham operation (Sham) or bilateral ovariectomy (Ovx and Ovx + YCJ). The Ovx + YCJ rats were administered 5×-concentrated YCJ at a dose of 10 mL/kg body weight per day. Six weeks after surgery, the rats were sacrificed, and indices of bone mass and bone histomorphometry were measured. The bone mineral density of the left femur was significantly higher in the Ovx + YCJ group compared with the Ovx group. In addition, the Ovx + YCJ group showed significantly higher measurements for bone formation rate compared with the Ovx group. These findings suggest that YCJ supplementation has a positive effect on bone metabolism and thus represents a possible intervention to slow the bone loss observed following menopause.

  2. Thymidine phosphorylase exerts complex effects on bone resorption and formation in myeloma

    PubMed Central

    Liu, Huan; Liu, Zhiqiang; Du, Juan; He, Jin; Lin, Pei; Amini, Behrang; Starbuck, Michael W.; Novane, Nora; Shah, Jatin J.; Davis, Richard E.; Hou, Jian; Gagel, Robert F.; Yang, Jing

    2016-01-01

    Myelomatous bone disease is characterized by the development of lytic bone lesions and a concomitant reduction in bone formation, leading to chronic bone pain and fractures. To understand the underlying mechanism, we investigated the contribution of myeloma-expressed thymidine phosphorylase (TP) to bone lesions. In osteoblast progenitors, TP upregulated the methylation of RUNX2 and osterix, leading to decreased bone formation. In osteoclast progenitors, TP upregulated the methylation of IRF8, thereby enhanced expression of NFATc1, leading to increased bone resorption. TP reversibly catalyzes thymidine into thymine and 2DDR. Myeloma-secreted 2DDR bound to integrin αVβ3/α5β1 in the progenitors, activated PI3K/Akt signaling, and increased DNMT3A expression, resulting in hypermethylation of RUNX2, osterix, and IRF8. This study elucidates an important mechanism for myeloma-induced bone lesions, suggesting that targeting TP may be a viable approach to healing resorbed bone in patients. As TP overexpression is common in bone-metastatic tumors, our findings could have additional mechanistic implications. PMID:27559096

  3. Prebiotics, probiotics, and synbiotics affect mineral absorption, bone mineral content, and bone structure.

    PubMed

    Scholz-Ahrens, Katharina E; Ade, Peter; Marten, Berit; Weber, Petra; Timm, Wolfram; Açil, Yahya; Glüer, Claus-C; Schrezenmeir, Jürgen

    2007-03-01

    Several studies in animals and humans have shown positive effects of nondigestible oligosaccharides (NDO) on mineral absorption and metabolism and bone composition and architecture. These include inulin, oligofructose, fructooligosaccharides, galactooligosaccharides, soybean oligosaccharide, and also resistant starches, sugar alcohols, and difructose anhydride. A positive outcome of dietary prebiotics is promoted by a high dietary calcium content up to a threshold level and an optimum amount and composition of supplemented prebiotics. There might be an optimum composition of fructooligosaccharides with different chain lengths (synergy products). The efficacy of dietary prebiotics depends on chronological age, physiological age, menopausal status, and calcium absorption capacity. There is evidence for an independent probiotic effect on facilitating mineral absorption. Synbiotics, i.e., a combination of probiotics and prebiotics, can induce additional effects. Whether a low content of habitual NDO would augment the effect of dietary prebiotics or synbiotics remains to be studied. The underlying mechanisms are manifold: increased solubility of minerals because of increased bacterial production of short-chain fatty acids, which is promoted by the greater supply of substrate; an enlargement of the absorption surface by promoting proliferation of enterocytes mediated by bacterial fermentation products, predominantly lactate and butyrate; increased expression of calcium-binding proteins; improvement of gut health; degradation of mineral complexing phytic acid; release of bone-modulating factors such as phytoestrogens from foods; stabilization of the intestinal flora and ecology, also in the presence of antibiotics; stabilization of the intestinal mucus; and impact of modulating growth factors such as polyamines. In conclusion, prebiotics are the most promising but also best investigated substances with respect to a bone-health-promoting potential, compared with probiotics

  4. Effect of Autologous Bone Marrow Stromal Cell Seeding and Bone Morphogenetic Protein-2 Delivery on Ectopic Bone Formation in a Microsphere/Poly(Propylene Fumarate) Composite

    PubMed Central

    Kempen, Diederik H.R.; Kruyt, Moyo C.; Lu, Lichun; Wilson, Clayton E.; Florschutz, Anthony V.; Yaszemski, Michael J.; Dhert, Wouter J.A.

    2009-01-01

    A biodegradable microsphere/scaffold composite based on the synthetic polymer poly(propylene fumarate) (PPF) holds promise as a scaffold for cell growth and sustained delivery vehicle for growth factors for bone regeneration. The objective of the current work was to investigate the in vitro release and in vivo bone forming capacity of this microsphere/scaffold composite containing bone morphogenetic protein-2 (BMP-2) in combination with autologous bone marrow stromal cells (BMSCs) in a goat ectopic implantation model. Three composites consisting of 0, 0.08, or 8 μg BMP-2 per mg of poly(lactic-co-glycolic acid) microspheres, embedded in a porous PPF scaffold, were combined with either plasma (no cells) or culture-expanded BMSCs. PPF scaffolds impregnated with a BMP-2 solution and combined with BMSCs as well as empty PPF scaffolds were also tested. The eight different composites were implanted subcutaneously in the dorsal thoracolumbar area of goats. Incorporation of BMP-2–loaded microspheres in the PPF scaffold resulted in a more sustained in vitro release with a lower burst phase, as compared to BMP-2–impregnated scaffolds. Histological analysis after 9 weeks of implantation showed bone formation in the pores of 11/16 composites containing 8 μg/mg BMP-2–loaded microspheres with no significant difference between composites with or without BMSCs (6/8 and 5/8, respectively). Bone formation was also observed in 1/8 of the BMP-2–impregnated scaffolds. No bone formation was observed in the other conditions. Overall, this study shows the feasibility of bone induction by BMP-2 release from microspheres/scaffold composites. PMID:18925831

  5. [Recruitment of osteogenic cells to bone formation sites during development and fracture repair - German Version].

    PubMed

    Böhm, A-M; Dirckx, N; Maes, C

    2016-04-01

    Recruitment of osteoblast lineage cells to their bone-forming locations is essential for skeletal development and fracture healing. In developing bones, osteoprogenitor cells invade the cartilage mold to establish the primary ossification center. Similarly, osteogenic cells infiltrate and populate the callus tissue that is formed following an injury. Proper bone development and successful fracture repair must, therefore, rely on controlled temporal and spatial navigation cues guiding the cells to the sites where new bone formation is needed. Some cellular mechanisms and molecular pathways involved have been elucidated.

  6. Bmp2 in osteoblasts of periosteum and trabecular bone links bone formation to vascularization and mesenchymal stem cells.

    PubMed

    Yang, Wuchen; Guo, Dayong; Harris, Marie A; Cui, Yong; Gluhak-Heinrich, Jelica; Wu, Junjie; Chen, Xiao-Dong; Skinner, Charles; Nyman, Jeffry S; Edwards, James R; Mundy, Gregory R; Lichtler, Alex; Kream, Barbara E; Rowe, David W; Kalajzic, Ivo; David, Val; Quarles, Darryl L; Villareal, Demetri; Scott, Greg; Ray, Manas; Liu, S; Martin, James F; Mishina, Yuji; Harris, Stephen E

    2013-09-15

    We generated a new Bmp2 conditional-knockout allele without a neo cassette that removes the Bmp2 gene from osteoblasts (Bmp2-cKO(ob)) using the 3.6Col1a1-Cre transgenic model. Bones of Bmp2-cKO(ob) mice are thinner, with increased brittleness. Osteoblast activity is reduced as reflected in a reduced bone formation rate and failure to differentiate to a mature mineralizing stage. Bmp2 in osteoblasts also indirectly controls angiogenesis in the periosteum and bone marrow. VegfA production is reduced in Bmp2-cKO(ob) osteoblasts. Deletion of Bmp2 in osteoblasts also leads to defective mesenchymal stem cells (MSCs), which correlates with the reduced microvascular bed in the periosteum and trabecular bones. Expression of several MSC marker genes (α-SMA, CD146 and Angiopoietin-1) in vivo, in vitro CFU assays and deletion of Bmp2 in vitro in α-SMA(+) MSCs support our conclusions. Critical roles of Bmp2 in osteoblasts and MSCs are a vital link between bone formation, vascularization and mesenchymal stem cells.

  7. Is suppression of bone formation during simulated weightlessness related to glucocorticoid levels

    NASA Technical Reports Server (NTRS)

    Morey-Holton, E. R.; Bomalaski, M. D.; Enayati-Gordon, E.; Gonsalves, M. R.; Wronski, T. J.

    1982-01-01

    To investigate the hypothesis that suppression of bone formation in the suspended rat model was the result of increased levels of corticosterone, experiments were performed on young, growing, male rats exposed either to 4 C or suspended for two weeks. Rats suspended on the model system, designed to simulate certain aspects of spaceflight, gained weight at a rate at least equal to control animals but still showed a significant suppression of bone formation within 7 days. Cold-exposed rats gained less weight than their corresponding control group and did not demonstrate any suppression of bone formation. These findings suggest: (1) tail suspension is less stressful than previously used harness systems; (2) suspension in young, rapidly growing rats causes a significant suppression of cortical bone formation; (3) cold exposure does not alter bone formation rate in rats of a similar age and strain to those suspended in this study; and (4) suppression of bone formation provoked by unloading the rear limbs is not due solely to sustained stimulation of the pituitary-adrenal system.

  8. Decursin from Angelica gigas suppresses RANKL-induced osteoclast formation and bone loss.

    PubMed

    Wang, Xin; Zheng, Ting; Kang, Ju-Hee; Li, Hua; Cho, Hyewon; Jeon, Raok; Ryu, Jae-Ha; Yim, Mijung

    2016-03-05

    Osteoclasts are the only cells capable of breaking down bone matrix, and excessive activation of osteoclasts is responsible for bone-destructive diseases. In this study, we investigated the effects of decursin from extract of Angelica gigas root on receptor activator of nuclear factor kappa B ligand (RANKL)-induced osteoclast formation using mouse bone marrow-derived macrophages (BMMs). Decursin inhibited RANKL-induced osteoclast formation without cytotoxicity. In particular, decursin maintains the characteristics of macrophages by blocking osteoclast differentiation by RANKL. Furthermore, the RANKL-stimulated bone resorption was diminished by decursin. Mechanistically, decursin blocked the RANKL-triggered ERK mitogen-activated protein kinases (MAPK) phosphorylation, which results in suppression of c-Fos and the nuclear factor of activated T cells (NFATc1) expression. In accordance with the in vitro study, decursin reduced lipopolysaccharide (LPS)- or ovariectomy (OVX)-induced bone loss in vivo. Therefore, decursin exerted an inhibitory effect on osteoclast formation and bone loss in vitro and in vivo. Decursin could be useful for the treatment of bone diseases associated with excessive bone resorption.

  9. Trabecular bone formation in the healing of the rodent molar tooth extraction socket.

    PubMed

    Devlin, H; Hoyland, J; Newall, J F; Ayad, S

    1997-12-01

    The aim of this study was to investigate the nature of the template structure on which trabecular bone formation occurs during healing of the rodent tooth extraction socket, a well studied bone healing system. The presence of collagen type II mRNA has previously been described in the healing socket, although the formation of the protein or cartilage has not been observed. However, recent evidence from developmental and other bone healing studies indicates that collagen type III may be important in forming the preliminary scaffold on which bone trabeculae are formed. The maxillary right molar teeth were removed from rats under general anaesthesia and the animals killed at various times afterward. The tissues were examined using histological, in situ hybridization, and immunohistochemical staining techniques. It was concluded that collagen type IIA mRNA was produced by osteoblast cells of the socket, but that collagen type II, if present, would account for less than 0.01% of the total proteins extracted. During bone formation, Sharpey's fibers were seen radiating from the peripheral bone toward the center of the socket. These optically active collagen fibers were inserted into the forming bone trabeculae and were recognized by antibodies raised against collagen type III. The arrangement and composition of these fibers therefore suggest that they form a preliminary framework on which deposition of woven bone trabeculae occurs.

  10. Effect of low gravity on calcium metabolism and bone formation (L-7)

    NASA Technical Reports Server (NTRS)

    Suda, Tatsuo

    1993-01-01

    Recently, attention has been focused on the disorders of bone and calcium metabolism during space flight. The skeletal system has evolved on the Earth under 1-g. Space flights under low gravity appear to cause substantial changes in bone and calcium homeostasis of the animals adapted to 1-g. A space experiment for the First Materials Processing Test (FMPT) was proposed to examine the effects of low gravity on calcium metabolism and bone formation using chick embryos loaded in a space shuttle. This space experiment was proposed based on the following two experimental findings. First, it has been reported that bone density decreases significantly during prolonged space flight. The data obtained from the US Skylab and the U.S.S.R. Salyut-6 cosmonauts have also documented that the degree of bone loss is related to the duration of space flight. Second, the US-Soviet joints space experiment demonstrated that the decrease in bone density under low gravity appears to be due to the decrease in bone formation rather than the increase in bone resorption. The purpose of our space experiment is, therefore, to investigate further the mechanisms of bone growth under low gravity using fertilized chick embryos.

  11. Brief communication: Identification of bone formation and resorption surfaces by reflected light microscopy.

    PubMed

    Martinez-Maza, Cayetana; Rosas, Antonio; Nieto-Diaz, Manuel

    2010-10-01

    Developmental and evolutionary changes in craniofacial morphology are a central issue in paleoanthropology, but the underlying bone growth processes have been scarcely studied. Relevant knowledge on bone growth dynamics can be obtained from the spatial distribution of bone formation and resorption activities. Determining these patterns from the valuable samples typically used in anthropology and palaeoanthropology necessarily implies nondestructive procedures. In this work, we present a methodology based on the analysis of high-resolution replicas by reflected light microscopy, describing how microfeatures related to bone formation and resorption activities are recognized on both recent and fossil bone surfaces. The proposed method yields highly similar images to those obtained with scanning electron microscope and has proven its utility in an analysis of a large sample of extant and extinct hominoids.

  12. Glycoprotein130 (Gp130)/interleukin-6 (IL-6) signalling in osteoclasts promotes bone formation in periosteal and trabecular bone.

    PubMed

    Johnson, Rachelle W; McGregor, Narelle E; Brennan, Holly J; Crimeen-Irwin, Blessing; Poulton, Ingrid J; Martin, T John; Sims, Natalie A

    2015-12-01

    Interleukin-6 (IL-6) and interleukin-11 (IL-11) receptors (IL-6R and IL-11R, respectively) are both expressed in osteoclasts and transduce signal via the glycoprotein130 (gp130) co-receptor, but the physiological role of this pathway is unclear. To determine the critical roles of gp130 signalling in the osteoclast, we generated mice using cathepsin K Cre (CtskCre) to disrupt gp130 signalling in osteoclasts. Bone marrow macrophages from CtskCre.gp130(f/f) mice generated more osteoclasts in vitro than cells from CtskCre.gp130(w/w) mice; these osteoclasts were also larger and had more nuclei than controls. While no increase in osteoclast numbers was observed in vivo, osteoclasts on trabecular bone surfaces of CtskCre.gp130(f/f) mice were more spread out than in control mice, but had no functional defect detectable by serum CTX1 levels or trabecular bone cartilage remnants. However, trabecular osteoblast number and mineralising surfaces were significantly lower in male CtskCre.gp130(f/f) mice compared to controls, and this was associated with a significantly lower trabecular bone volume at 12 weeks of age. Furthermore, CtskCre.gp130(f/f) mice exhibited greatly suppressed periosteal bone formation at this age, indicated by significant reductions in both double-labelled surface and mineral apposition rate. By 26 weeks of age, CtskCre.gp130(f/f) mice exhibited narrower femora, with lower periosteal and endocortical perimeters than CtskCre.gp130(w/w) controls. Since IL-6 and IL-11R global knockout mice exhibited a similar reduction in femoral width, we also assessed periosteal bone formation in those strains, and found bone forming surfaces were also reduced in male IL-6 null mice. These data suggest that IL-6/gp130 signalling in the osteoclast is not essential for normal bone resorption in vivo, but maintains both trabecular and periosteal bone formation in male mice by promoting osteoblast activity through the stimulation of osteoclast-derived "coupling factors" and

  13. Tanshinol Rescues the Impaired Bone Formation Elicited by Glucocorticoid Involved in KLF15 Pathway

    PubMed Central

    Yang, Yajun; Su, Yanjie; Wang, Dongtao; Chen, Yahui; Liu, Yuyu; Luo, Shiying; Wu, Tie

    2016-01-01

    Decreased bone formation is responsible for the pathogenesis of glucocorticoid- (GC-) induced osteoporosis (GIO), while the mechanism remains to be elucidated. The aim was to investigate how natural antioxidant tanshinol attenuates oxidative stress and rescues impaired bone formation elicited by GC in Sprague-Dawley rats and in C2C12 cells and/or MC3T3-E1 cells. The results showed that tanshinol prevented bone loss and decreased biomechanical characteristics and suppressed reduction of biomarkers related to osteogenesis in GIO rats. Further study revealed that tanshinol reversed decrease of transcription activity of Osterix-luc and rescued impairment of osteoblastic differentiation and bone formation involved in induction of KLF15 mRNA. Meanwhile, tanshinol diminished inhibition of protein expression of β-catenin and Tcf4 and transcription activity of Tcf4-luc induced by GC, especially under conditions of KLF siRNA in vitro. Additionally, tanshinol attenuated increase of reactive oxygen species (ROS) generation, phosphorylation of p66Shc expression, TUNEL-positive cells, and caspase-3 activity elicited by KLF15 under conditions of GC. Taken together, the present findings suggest that tanshinol attenuated the decrease of bone formation and bone mass and bone quality elicited by GC involved in KLF15/Wnt signaling transduction and counteracted GC-evoked oxidative stress and subsequent cell apoptosis involved in KLF15/p66Shc pathway cascade. PMID:27051474

  14. Pulsed electromagnetic fields partially preserve bone mass, microarchitecture, and strength by promoting bone formation in hindlimb-suspended rats.

    PubMed

    Jing, Da; Cai, Jing; Wu, Yan; Shen, Guanghao; Li, Feijiang; Xu, Qiaoling; Xie, Kangning; Tang, Chi; Liu, Juan; Guo, Wei; Wu, Xiaoming; Jiang, Maogang; Luo, Erping

    2014-10-01

    A large body of evidence indicates that pulsed electromagnetic fields (PEMF), as a safe and noninvasive method, could promote in vivo and in vitro osteogenesis. Thus far, the effects and underlying mechanisms of PEMF on disuse osteopenia and/or osteoporosis remain poorly understood. Herein, the efficiency of PEMF on osteoporotic bone microarchitecture, bone strength, and bone metabolism, together with its associated signaling pathway mechanism, was systematically investigated in hindlimb-unloaded (HU) rats. Thirty young mature (3-month-old), male Sprague-Dawley rats were equally assigned to control, HU, and HU + PEMF groups. The HU + PEMF group was subjected to daily 2-hour PEMF exposure at 15 Hz, 2.4 mT. After 4 weeks, micro-computed tomography (µCT) results showed that PEMF ameliorated the deterioration of trabecular and cortical bone microarchitecture. Three-point bending test showed that PEMF mitigated HU-induced reduction in femoral mechanical properties, including maximum load, stiffness, and elastic modulus. Moreover, PEMF increased serum bone formation markers, including osteocalcin (OC) and N-terminal propeptide of type 1 procollagen (P1NP); nevertheless, PEMF exerted minor inhibitory effects on bone resorption markers, including C-terminal crosslinked telopeptides of type I collagen (CTX-I) and tartrate-resistant acid phosphatase 5b (TRAcP5b). Bone histomorphometric analysis demonstrated that PEMF increased mineral apposition rate, bone formation rate, and osteoblast numbers in cancellous bone, but PEMF caused no obvious changes on osteoclast numbers. Real-time PCR showed that PEMF promoted tibial gene expressions of Wnt1, LRP5, β-catenin, OPG, and OC, but did not alter RANKL, RANK, or Sost mRNA levels. Moreover, the inhibitory effects of PEMF on disuse-induced osteopenia were further confirmed in 8-month-old mature adult HU rats. Together, these results demonstrate that PEMF alleviated disuse-induced bone loss by promoting skeletal anabolic activities

  15. Bone formation in transforming growth factor beta-1-coated porous poly(propylene fumarate) scaffolds.

    PubMed

    Vehof, Johan W M; Fisher, John P; Dean, David; van der Waerden, Jan-Paul C M; Spauwen, Paul H M; Mikos, Antonios G; Jansen, John A

    2002-05-01

    This study determined the bone growth into pretreated poly(propylene fumarate) (PPF) scaffolds implanted into a subcritical size, rabbit cranial defect. PPF scaffolds were constructed by using a photocrosslinking-porogen leaching technique. These scaffolds were then either prewetted (PPF-Pw), treated with RF glow-discharge (PPF-Gd), coated with fibronectin (PPF-Fn), or coated with rhTGF-beta1 (PPF-TGF-beta1). One of each scaffold type was then placed into the cranium of nine rabbits. The rabbits were sacrificed after 8 weeks, and the scaffolds were retrieved for histological analysis. The most bone formation was present in the PPF-TGF-beta1 implants; the newly formed bone had a trabecular appearance together with bone marrow-like tissue. Little or no bone formation was observed in implants without rhTGF-beta1. These histological findings were confirmed by image analysis. Bone surface area, bone area percentage, pore fill percentage, and pore area percentage were significantly higher in the rhTGF-beta1-coated implants than in the noncoated implants. No statistical difference was seen between the PPF-Fn, PPF-Pw, or PPF-Gd scaffolds for these parameters. Quadruple fluorochrome labeling showed that in PPF-TGF-beta1 implants bone formation mainly started in the interior of a pore and proceeded toward the scaffold. We conclude that (a) PPF-TGF-beta1 scaffolds can indeed adequately induce bone formation in porous PPF, and (b) PPF scaffolds prepared by the photocrosslinking-porogen leaching technique are good candidates for the creation of bone graft substitutes.

  16. Alveolar Ridge Conservation by Early Bone Formation After Tooth Extraction in Rabbits. A Histomorphological Study.

    PubMed

    Cantín, Mario; Olate, Sergio; Fuentes, Ramón; Vásquez, Bélgica

    2015-03-01

    Alveolar ridge volume loss is an irreversible process. To prevent this physiological event, which typically result in significant local anatomical changes in both the horizontal and the vertical dimension, some strategies are indicated to minimize the loss of ridge volume that typically follows tooth extraction. The purpose of this study was to evaluate if three different bone grafts could promote new bone formation in the alveolar socket following tooth extraction for the alveolar ridge conservation. First mandibular molars of male adults rabbits were extracted and the extraction sockets were randomly treated with three different bone grafts, one xenograft and two alloplastic grafts, and a group that received no treatment (blood clot). The extraction sockets of selected rabbits from each group were evaluated at 4, 6, or 8-week post-extraction. The results indicated that the extraction sockets treated with alloplastic graft (biphasic calcium phosphate) exhibited lamellar bone formation (6.5%) as early as four weeks after the extraction was performed. Moreover, the degree of new bone formation was significantly higher (P<0.05) in the extraction sockets treated with biphasic calcium phosphate at 8-week post-extraction than that in the other study groups. In this study, we demonstrated that the proposed animal model is useful to evaluate the bone formation after tooth extraction and the alveolar ridge conservation is feasible. The new bone formation and alveolar ridge preservation with bone graft after extraction of molar teeth, could result in the maintenance of sufficient bone volume to place an implant in an ideal restorative position without the need for ancillary implant site development procedures.

  17. Mesenchymal Deletion of Histone Demethylase NO66 in Mice Promotes Bone Formation

    PubMed Central

    Chen, Qin; Sinha, Krishna; Deng, Jian Min; Yasuda, Hideyo; Krahe, Ralf; Behringer, Richard R.; de Crombrugghe, Benoit

    2016-01-01

    Our previous studies indicated that the Jumonji C (JmjC)-domain-containing NO66 is a histone demethylase with specificity for methylated histone H3K4 and H3K36. NO66 binds to the transcription factor Osterix (Osx) and inhibits its transcriptional activity in promoter assays. However, the physiological role of NO66 in formation of mammalian bones is unknown. Here, using a genetically engineered mouse model, we show that during early skeletal development, Prx1-Cre dependent mesenchymal deletion of NO66 promotes osteogenesis and formation of both endochondral as well as intramembranous skeletal elements, leading to a larger skeleton and a high bone mass phenotype in adult mice. The excess bone formation in mice where NO66 was deleted in cells of mesenchymal origin is associated with an increase in the number of preosteoblasts and osteoblasts. Further analysis revealed that in the embryonic limbs and adult calvaria of mice with deletion of NO66 in cells of mesenchymal origin, expression of several genes including bone morphogenetic protein 2, insulin-like growth factor 1 and osteoclast inhibitor osteoprotegerin was increased, concurrent with an increase in expression of bone formation markers such as Osx, type I collagen and bone sialoprotein. Taken together, our results provide the first in vivo evidence that NO66 histone demethylase plays an important role in mammalian osteogenesis during early development as well as in adult bone homeostasis. We postulate that NO66 regulates bone formation, at least in part, via regulating the number of bone-forming cells and expression of multiple genes that are critical for these processes. PMID:25736226

  18. Alveolar Ridge Conservation by Early Bone Formation After Tooth Extraction in Rabbits. A Histomorphological Study

    PubMed Central

    Cantín, Mario; Olate, Sergio; Fuentes, Ramón; Vásquez, Bélgica

    2016-01-01

    SUMMARY Alveolar ridge volume loss is an irreversible process. To prevent this physiological event, which typically result in significant local anatomical changes in both the horizontal and the vertical dimension, some strategies are indicated to minimize the loss of ridge volume that typically follows tooth extraction. The purpose of this study was to evaluate if three different bone grafts could promote new bone formation in the alveolar socket following tooth extraction for the alveolar ridge conservation. First mandibular molars of male adults rabbits were extracted and the extraction sockets were randomly treated with three different bone grafts, one xenograft and two alloplastic grafts, and a group that received no treatment (blood clot). The extraction sockets of selected rabbits from each group were evaluated at 4, 6, or 8-week post-extraction. The results indicated that the extraction sockets treated with alloplastic graft (biphasic calcium phosphate) exhibited lamellar bone formation (6.5%) as early as four weeks after the extraction was performed. Moreover, the degree of new bone formation was significantly higher (P<0.05) in the extraction sockets treated with biphasic calcium phosphate at 8-week post-extraction than that in the other study groups. In this study, we demonstrated that the proposed animal model is useful to evaluate the bone formation after tooth extraction and the alveolar ridge conservation is feasible. The new bone formation and alveolar ridge preservation with bone graft after extraction of molar teeth, could result in the maintenance of sufficient bone volume to place an implant in an ideal restorative position without the need for ancillary implant site development procedures. PMID:27840551

  19. Role of Osterix and MicroRNAs in Bone Formation and Tooth Development

    PubMed Central

    Wang, Chuan; Liao, Haiqing; Cao, Zhengguo

    2016-01-01

    Osterix (Osx) is an osteoblast-specific transcription factor that is essential for bone formation. MicroRNAs (miRNAs) are ~22-nucleotide-long noncoding RNAs that play important regulatory roles in animals and plants by targeting mRNAs for cleavage or translational repression. They can also control osteoblast-mediated bone formation and osteoclast-related bone remodeling. The vital roles of Osx and miRNAs during bone formation have been well studied, but very few studies have discussed their co-functions and the relationships between them. In this review, we outline the significant functions of Osx and miRNAs on certain cell types during osteogenesis and illustrate their roles during tooth development. More importantly, we discuss the relationship between Osx and miRNAs, which we believe could lead to a new treatment for skeletal and periodontal diseases. PMID:27543160

  20. A delay in pubertal onset affects the covariation of body weight, estradiol, and bone size.

    PubMed

    Yingling, Vanessa R

    2009-04-01

    The skeletal system functions as a locomotive organ and a mineral reservoir and combinations of genetic and environmental factors affect the skeletal system. Although delayed puberty is associated with compromised bone mass, suppression of estrogen should be beneficial to cortical strength. The purpose was to employ path analysis to study bone strength and delayed puberty. Forty-five female rats were randomly assigned to a control group (n = 15) and an experimental group (n = 30) that received injections of gonadotropin releasing hormone antagonist (GnRH-a). Causal models were constructed by specifying directed paths between bone traits. The first model tested the hypothesis that the functional relationships between bone traits and body weight were altered by a delay in pubertal onset. GnRH-a injections during puberty altered the covariation between body weight and bone size. The second model was constructed to test the hypothesis that variability in stiffness was causally related to variability in body weight. The model also tested the relationship between the periosteal and endocortical surfaces and their relationship to stiffness. There was no change in the relationship between the surfaces in the GnRH-a group. The third model determined the effect of estradiol on both total area and relative cortical area in both groups. The relationship between periosteal surface and serum estradiol levels was only significant during estrogen suppression. These data suggest that increases in body weight during or prior to puberty may not be protective of bone strength.

  1. Ephrin B1 regulates bone marrow stromal cell differentiation and bone formation by influencing TAZ transactivation via complex formation with NHERF1.

    PubMed

    Xing, Weirong; Kim, Jonghyun; Wergedal, Jon; Chen, Shin-Tai; Mohan, Subburaman

    2010-02-01

    Mutations of ephrin B1 in humans result in craniofrontonasal syndrome. Because little is known of the role and mechanism of action of ephrin B1 in bone, we examined the function of osteoblast-produced ephrin B1 in vivo and identified the molecular mechanism by which ephrin B1 reverse signaling regulates bone formation. Targeted deletion of the ephrin B1 gene in type 1alpha2 collagen-producing cells resulted in severe calvarial defects, decreased bone size, bone mineral density, and trabecular bone volume, caused by impairment in osterix expression and osteoblast differentiation. Coimmunoprecipitation of the TAZ complex with TAZ-specific antibody revealed a protein complex containing ephrin B1, PTPN13, NHERF1, and TAZ in bone marrow stromal (BMS) cells. Activation of ephrin B1 reverse signaling with soluble EphB2-Fc led to a time-dependent increase in TAZ dephosphorylation and shuttling from cytoplasm to nucleus. Treatment of BMS cells with exogenous EphB2-Fc resulted in a 4-fold increase in osterix expression as determined by Western blotting. Disruption of TAZ expression using specific lentivirus small hairpin RNA (shRNA) decreased TAZ mRNA by 80% and ephrin B1 reverse signaling-mediated increases in osterix mRNA by 75%. Knockdown of NHERF1 expression reduced basal levels of osterix expression by 90% and abolished ephrin B1-mediated induction of osterix expression. We conclude that locally produced ephrin B1 mediates its effects on osteoblast differentiation by a novel molecular mechanism in which activation of reverse signaling leads to dephosphorylation of TAZ and subsequent release of TAZ from the ephrin B1/NHERF1/TAZ complex to translocate to the nucleus to induce expression of the osterix gene and perhaps other osteoblast differentiation genes. Our findings provide strong evidence that ephrin B1 reverse signaling in osteoblasts is critical for BMS cell differentiation and bone formation.

  2. Effect of coating Straumann Bone Ceramic with Emdogain on mesenchymal stromal cell hard tissue formation.

    PubMed

    Mrozik, Krzysztof Marek; Gronthos, Stan; Menicanin, Danijela; Marino, Victor; Bartold, P Mark

    2012-06-01

    Periodontal tissue engineering requires a suitable biocompatible scaffold, cells with regenerative capacity, and instructional molecules. In this study, we investigated the capacity of Straumann Bone Ceramic coated with Straumann Emdogain, a clinical preparation of enamel matrix protein (EMP), to aid in hard tissue formation by post-natal mesenchymal stromal cells (MSCs) including bone marrow stromal cells (BMSCs) and periodontal ligament fibroblasts (PDLFs). MSCs were isolated and ex vivo-expanded from human bone marrow and periodontal ligament and, in culture, allowed to attach to Bone Ceramic in the presence or absence of Emdogain. Gene expression of bone-related proteins was investigated by real time RT-PCR for 72 h, and ectopic bone formation was assessed histologically in subcutaneous implants of Bone Ceramic containing MSCs with or without Emdogain in NOD/SCID mice. Alkaline phosphatase activity was also assessed in vitro, in the presence or absence of Emdogain. Collagen-I mRNA was up-regulated in both MSC populations over the 72-h time course with Emdogain. Expression of BMP-2 and the osteogenic transcription factor Cbfa-1 showed early stimulation in both MSC types after 24 h. In contrast, expression of BMP-4 was consistently down-regulated in both MSC types with Emdogain. Up-regulation of osteopontin and periostin mRNA was restricted to BMSCs, while higher levels of bone sialoprotein-II were observed in PDLFs with Emdogain. Furthermore, alkaline phosphatase activity levels were reduced in both BMSCs and PDLFs in the presence of Emdogain. Very little evidence was found for ectopic bone formation following subcutaneous implantation of MSCs with Emdogain-coated or -uncoated Bone Ceramic in NOD/SCID mice. The early up-regulation of several important bone-related genes suggests that Emdogain may have a significant stimulatory effect in the commitment of mesenchymal cells to osteogenic differentiation in vitro. While Emdogain inhibited AP activity and appeared

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

    SciTech Connect

    Gilmour, Peter S.; O'Shea, Patrick J.; Fagura, Malbinder; Pilling, James E.; Sanganee, Hitesh; Wada, Hiroki; Courtney, Paul F.; Kavanagh, Stefan; Hall, Peter A.; Escott, K. Jane

    2013-10-15

    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 inhibitors 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

  4. A 5-year exercise program in pre- and peripubertal children improves bone mass and bone size without affecting fracture risk.

    PubMed

    Detter, Fredrik T L; Rosengren, Björn E; Dencker, Magnus; Nilsson, J-Å; Karlsson, Magnus K

    2013-04-01

    We studied the effect in children of an exercise intervention program on fracture rates and skeletal traits. Fractures were registered for 5 years in a population-based prospective controlled exercise intervention study that included children aged 6-9 years at study start, 446 boys and 362 girls in the intervention group and 807 boys and 780 girls in the control group. Intervention subjects received 40 min/school day of physical education and controls, 60 min/week. In 73 boys and 48 girls in the intervention group and 52 boys and 48 girls in the control group, bone mineral density (BMD, g/cm(2)) and bone area (mm(2)) were followed annually by dual-energy X-ray absorptiometry, after which annual changes were calculated. At follow-up we also assessed trabecular and cortical volumetric BMD (g/cm(3)) and bone structure by peripheral computed tomography in the tibia and radius. There were 20.0 fractures/1,000 person-years in the intervention group and 18.5 fractures/1,000 person-years in the control group, resulting in a rate ratio of 1.08 (0.79-1.47) (mean and 95 % CI). The gain in spine BMD was higher in both girls (difference 0.01 g/cm(2), 0.005-0.019) and boys (difference 0.01 g/cm(2), 0.001-0.008) in the intervention group. Intervention girls also had higher gain in femoral neck area (difference 0.04 mm(2), 0.005-0.083) and at follow-up larger tibial bone mineral content (difference 0.18 g, 0.015-0.35), larger tibial cortical area (difference 17 mm(2), 2.4-31.3), and larger radial cross-sectional area (difference 11.0 mm(2), 0.63-21.40). As increased exercise improves bone mass and in girls bone size without affecting fracture risk, society ought to encourage exercise during growth.

  5. The bone-muscle ratio of fetal lambs is affected more by maternal nutrition during pregnancy than by maternal size.

    PubMed

    Firth, E C; Rogers, C W; Vickers, M; Kenyon, P R; Jenkinson, C M C; Blair, H T; Johnson, P L; Mackenzie, D D S; Peterson, S W; Morris, S T

    2008-06-01

    Bone formation and loss are related to the strain imposed on bone by muscle forces. Bone mineral content (BMC) and lean mass (LM) of fetal lambs was determined at day 140 of pregnancy in 8 groups of ewes, which were of either large or small body size, on either high (ad libitum) or maintenance pasture intake from day 21 of pregnancy, or carrying either singletons or twins. BMC and LM (using DXA scanning) of fetal hindquarters/spine were corrected to leg length. BMC and LM were less in twin than singleton groups (P < 0.001). Large ewes on high intake produced single fetuses with a (group mean) BMC/LM ratio that was higher (P < 0.002) than that in fetuses of large ewes with singletons on maintenance intake or twins on either high or maintenance intakes, the ratios of which were not different. In single fetuses from small ewes on high intake, the BMC/LM ratio was higher than those from small ewes with singletons on maintenance intake or twins on either high or maintenance intakes, the ratios of which were not different. The ratio was not different in singleton fetuses of ewes on high intake, whether they were large or small. Different fetal environments resulted in a given amount of muscle being associated with a higher or lower bone mass. Dietary intake during pregnancy was more important than maternal size in affecting the ratio. We conclude that intrauterine environmental factors may be important in determining bone mass postnatally, and possibly later in life.

  6. Decreased Bone Formation Explains Osteoporosis in a Genetic Mouse Model of Hemochromatosiss

    PubMed Central

    Doyard, Mathilde; Chappard, Daniel; Leroyer, Patricia; Roth, Marie-Paule; Loréal, Olivier; Guggenbuhl, Pascal

    2016-01-01

    Osteoporosis may complicate iron overload diseases such as genetic hemochromatosis. However, molecular mechanisms involved in the iron-related osteoporosis remains poorly understood. Recent in vitro studies support a role of osteoblast impairment in iron-related osteoporosis. Our aim was to analyse the impact of excess iron in Hfe-/- mice on osteoblast activity and on bone microarchitecture. We studied the bone formation rate, a dynamic parameter reflecting osteoblast activity, and the bone phenotype of Hfe−/− male mice, a mouse model of human hemochromatosis, by using histomorphometry. Hfe−/− animals were sacrificed at 6 months and compared to controls. We found that bone contains excess iron associated with increased hepatic iron concentration in Hfe−/− mice. We have shown that animals with iron overload have decreased bone formation rate, suggesting a direct impact of iron excess on active osteoblasts number. For bone mass parameters, we showed that iron deposition was associated with bone loss by producing microarchitectural impairment with a decreased tendency in bone trabecular volume and trabecular number. A disorganization of trabecular network was found with marrow spaces increased, which was confirmed by enhanced trabecular separation and star volume of marrow spaces. These microarchitectural changes led to a loss of connectivity and complexity in the trabecular network, which was confirmed by decreased interconnectivity index and increased Minkowski’s fractal dimension. Our results suggest for the first time in a genetic hemochromatosis mouse model, that iron overload decreases bone formation and leads to alterations in bone mass and microarchitecture. These observations support a negative effect of iron on osteoblast recruitment and/or function, which may contribute to iron-related osteoporosis. PMID:26829642

  7. Estrogen receptor α in osteocytes regulates trabecular bone formation in female mice.

    PubMed

    Kondoh, Shino; Inoue, Kazuki; Igarashi, Katsuhide; Sugizaki, Hiroe; Shirode-Fukuda, Yuko; Inoue, Erina; Yu, Taiyong; Takeuchi, Jun K; Kanno, Jun; Bonewald, Lynda F; Imai, Yuuki

    2014-03-01

    Estrogens are well known steroid hormones necessary to maintain bone health. In addition, mechanical loading, in which estrogen signaling may intersect with the Wnt/β-catenin pathway, is essential for bone maintenance. As osteocytes are known as the major mechanosensory cells embedded in mineralized bone matrix, osteocyte ERα deletion mice (ERα(ΔOcy/ΔOcy)) were generated by mating ERα floxed mice with Dmp1-Cre mice to determine the role of ERα in osteocytes. Trabecular bone mineral density of female, but not male ERα(ΔOcy/ΔOcy) mice was significantly decreased. Bone formation parameters in ERα(ΔOcy/ΔOcy) were significantly decreased while osteoclast parameters were unchanged. This suggests that ERα in osteocytes exerts osteoprotective function by positively controlling bone formation. To identify potential targets of ERα, gene array analysis of Dmp1-GFP osteocytes sorted by FACS from ERα(ΔOcy/ΔOcy) and control mice was performed. Gene expression microarray followed by gene ontology analyses revealed that osteocytes from ERα(ΔOcy/ΔOcy) highly expressed genes categorized in 'Secreted' when compared to control osteocytes. Among them, expression of Mdk and Sostdc1, both of which are Wnt inhibitors, was significantly increased without alteration of expression of the mature osteocyte markers such as Sost and β-catenin. Moreover, hindlimb suspension experiments showed that trabecular bone loss due to unloading was greater in ERα(ΔOcy/ΔOcy) mice without cortical bone loss. These data suggest that ERα in osteocytes has osteoprotective functions in trabecular bone formation through regulating expression of Wnt antagonists, but conversely plays a negative role in cortical bone loss due to unloading.

  8. A Computational Analysis of Bone Formation in the Cranial Vault in the Mouse

    PubMed Central

    Lee, Chanyoung; Richtsmeier, Joan T.; Kraft, Reuben H.

    2015-01-01

    Bones of the cranial vault are formed by the differentiation of mesenchymal cells into osteoblasts on a surface that surrounds the brain, eventually forming mineralized bone. Signaling pathways causative for cell differentiation include the actions of extracellular proteins driven by information from genes. We assume that the interaction of cells and extracellular molecules, which are associated with cell differentiation, can be modeled using Turing’s reaction–diffusion model, a mathematical model for pattern formation controlled by two interacting molecules (activator and inhibitor). In this study, we hypothesize that regions of high concentration of an activator develop into primary centers of ossification, the earliest sites of cranial vault bone. In addition to the Turing model, we use another diffusion equation to model a morphogen (potentially the same as the morphogen associated with formation of ossification centers) associated with bone growth. These mathematical models were solved using the finite volume method. The computational domain and model parameters are determined using a large collection of experimental data showing skull bone formation in mouse at different embryonic days in mice carrying disease causing mutations and their unaffected littermates. The results show that the relative locations of the five ossification centers that form in our model occur at the same position as those identified in experimental data. As bone grows from these ossification centers, sutures form between the bones. PMID:25853124

  9. Deletion of Nrf2 reduces skeletal mechanical properties and decreases load-driven bone formation.

    PubMed

    Sun, Yong-Xin; Li, Lei; Corry, Kylie A; Zhang, Pei; Yang, Yang; Himes, Evan; Mihuti, Cristina Layla; Nelson, Cecilia; Dai, Guoli; Li, Jiliang

    2015-05-01

    Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor expressed in many cell types, including osteoblasts, osteocytes, and osteoclasts. Nrf2 has been considered a master regulator of cytoprotective genes against oxidative and chemical insults. The lack of Nrf2 can induce pathologies in multiple organs. The aim of this study was to investigate the role of Nrf2 in load-driven bone metabolism using Nrf2 knockout (KO) mice. Compared to age-matched littermate wild-type controls, Nrf2 KO mice have significantly lowered femoral bone mineral density (-7%, p<0.05), bone formation rate (-40%, p<0.05), as well as ultimate force (-11%, p<0.01). The ulna loading experiment showed that Nrf2 KO mice were less responsive than littermate controls, as indicated by reduction in relative mineralizing surface (rMS/BS, -69%, p<0.01) and relative bone formation rate (rBFR/BS, -84%, p<0.01). Furthermore, deletion of Nrf2 suppressed the load-driven gene expression of antioxidant enzymes and Wnt5a in cultured primary osteoblasts. Taken together, the results suggest that the loss-of-function mutation of Nrf2 in bone impairs bone metabolism and diminishes load-driven bone formation.

  10. Ectopic Osteoid and Bone Formation by Three Calcium-Phosphate Ceramics in Rats, Rabbits and Dogs

    PubMed Central

    Wang, Liao; Zhang, Bi; Bao, Chongyun; Habibovic, Pamela; Hu, Jing; Zhang, Xingdong

    2014-01-01

    Calcium phosphate ceramics with specific physicochemical properties have been shown to induce de novo bone formation upon ectopic implantation in a number of animal models. In this study we explored the influence of physicochemical properties as well as the animal species on material-induced ectopic bone formation. Three bioceramics were used for the study: phase-pure hydroxyapatite (HA) sintered at 1200°C and two biphasic calcium phosphate (BCP) ceramics, consisting of 60 wt.% HA and 40 wt.% TCP (β-Tricalcium phosphate), sintered at either 1100°C or 1200°C. 108 samples of each ceramic were intramuscularly implanted in dogs, rabbits, and rats for 6, 12, and 24 weeks respectively. Histological and histomorphometrical analyses illustrated that ectopic bone and/or osteoid tissue formation was most pronounced in BCP sintered at 1100°C and most limited in HA, independent of the animal model. Concerning the effect of animal species, ectopic bone formation reproducibly occurred in dogs, while in rabbits and rats, new tissue formation was mainly limited to osteoid. The results of this study confirmed that the incidence and the extent of material-induced bone formation are related to both the physicochemical properties of calcium phosphate ceramics and the animal model. PMID:25229501

  11. The Transcriptional Modulator Interferon-Related Developmental Regulator 1 in Osteoblasts Suppresses Bone Formation and Promotes Bone Resorption.

    PubMed

    Iezaki, Takashi; Onishi, Yuki; Ozaki, Kakeru; Fukasawa, Kazuya; Takahata, Yoshifumi; Nakamura, Yukari; Fujikawa, Koichi; Takarada, Takeshi; Yoneda, Yukio; Yamashita, Yui; Shioi, Go; Hinoi, Eiichi

    2016-03-01

    Bone homeostasis is maintained by the synergistic actions of bone-resorbing osteoclasts and bone-forming osteoblasts. Although interferon-related developmental regulator 1 (Ifrd1) has been identified as a transcriptional coactivator/repressor in various cells, little attention has been paid to its role in osteoblastogenesis and bone homeostasis thus far. Here, we show that Ifrd1 is a critical mediator of both the cell-autonomous regulation of osteoblastogenesis and osteoblast-dependent regulation of osteoclastogenesis. Osteoblast-specific deletion of murine Ifrd1 increased bone formation and decreased bone resorption, causing high bone mass. Ifrd1 deficiency enhanced osteoblast differentiation and maturation along with increased expression of Runx2 and osterix (Osx). Mechanistically, Ifrd1 deficiency increased the acetylation status of p65, a component of NF-κB, at residues K122 and K123 via the attenuation of the interaction between p65 and histone deacetylase (HDAC). This led to the nuclear export of p65 and a decrease in NF-κB-dependent Smad7 expression and the subsequent enhancement of Smad1/Smad5/Smad8-dependent transcription. Moreover, a high bone mass phenotype in the osteoblast-specific deletion of Ifrd1 was markedly rescued by the introduction of one Osx-floxed allele but not of Runx2-floxed allele. Coculture experiments revealed that Ifrd1-deficient osteoblasts have a higher osteoprotegerin (OPG) expression and a lower ability to support osteoclastogenesis. Ifrd1 deficiency attenuated the interaction between β-catenin and HDAC, subsequently increasing the acetylation of β-catenin at K49, leading to its nuclear accumulation and the activation of the β-catenin-dependent transcription of OPG. Collectively, the expression of Ifrd1 in osteoblasts repressed osteoblastogenesis and activated osteoclastogenesis through modulating the NF-κB/Smad/Osx and β-catenin/OPG pathways, respectively. These findings suggest that Ifrd1 has a pivotal role in bone

  12. Palmitic Acid Reduces Circulating Bone Formation Markers in Obese Animals and Impairs Osteoblast Activity via C16-Ceramide Accumulation.

    PubMed

    Alsahli, Ahmad; Kiefhaber, Kathryn; Gold, Tziporah; Muluke, Munira; Jiang, Hongfeng; Cremers, Serge; Schulze-Späte, Ulrike

    2016-05-01

    Obesity and impaired lipid metabolism increase circulating and local fatty acid (FA) levels. Our previous studies showed that a high high-saturated -fat diet induced greater bone loss in mice than a high high-unsaturated-fat diet due to increased osteoclast numbers and activity. The impact of elevated FA levels on osteoblasts is not yet clear. We induced obesity in 4 week old male mice using a palmitic acid (PA)- or oleic acid (OA)-enriched high fat high-fat diet (HFD) (20 % of calories from FA), and compared them to mice on a normal (R) caloric diet (10 % of calories from FA). We collected serum to determine FA and bone metabolism marker levels. Primary osteoblasts were isolated; cultured in PA, OA, or control (C) medium; and assessed for mineralization activity, gene expression, and ceramide levels. Obese animals in the PA and OA groups had significantly lower serum levels of bone formation markers P1NP and OC compared to normal weight animals (*p < 0.001), with the lowest marker levels in animals on an PA-enriched HFD (*p < 0.001). Accordingly, elevated levels of PA significantly reduced osteoblast mineralization activity in vitro (*p < 0.05). Elevated PA intake significantly increased C16 ceramide accumulation. This accumulation was preventable through inhibition of SPT2 (serine palmitoyl transferase 2) using myriocin. Elevated levels of PA reduce osteoblast function in vitro and bone formation markers in vivo. Our findings suggest that saturated PA can compromise bone health by affecting osteoblasts, and identify a potential mechanism through which obesity promotes bone loss.

  13. Forskolin enhances in vivo bone formation by human mesenchymal stromal cells.

    PubMed

    Doorn, Joyce; Siddappa, Ramakrishnaiah; van Blitterswijk, Clemens A; de Boer, Jan

    2012-03-01

    Activation of the protein kinase A (PKA) pathway with dibutyryl cyclic adenosine monophosphate (db-cAMP) was recently shown to enhance osteogenic differentiation of human mesenchymal stromal cells (hMSCs) in vitro and bone formation in vivo. The major drawback of this compound is its inhibitory effect on proliferation of hMSCs. Therefore, we investigated whether fine-tuning of the dose and timing of PKA activation could enhance bone formation even further, with minimum effects on proliferation. To test this, we selected two different PKA activators (8-bromo-cAMP (8-br-cAMP) and forskolin) and compared their effects on proliferation and osteogenic differentiation with those of db-cAMP. We found that all three compounds induced alkaline phosphatase levels, bone-specific target genes, and secretion of insulin-like growth factor-1, although 8-br-cAMP induced adipogenic differentiation in long-term cultures and was thus considered unsuitable for further in vivo testing. All three compounds inhibited proliferation of hMSCs in a dose-dependent manner, with forskolin inhibiting proliferation most. The effect of forskolin on in vivo bone formation was tested by pretreating hMSCs before implantation, and we observed greater amounts of bone using forskolin than db-cAMP. Our data show forskolin to be a novel agent that can be used to increase bone formation and also suggests a role for PKA in the delicate balance between adipogenic and osteogenic differentiation.

  14. TGF-β and BMP Signaling in Osteoblast Differentiation and Bone Formation

    PubMed Central

    Chen, Guiqian; Deng, Chuxia; Li, Yi-Ping

    2012-01-01

    Transforming growth factor-beta (TGF-β)/bone morphogenic protein (BMP) signaling is involved in a vast majority of cellular processes and is fundamentally important throughout life. TGF-β/BMPs have widely recognized roles in bone formation during mammalian development and exhibit versatile regulatory functions in the body. Signaling transduction by TGF-β/BMPs is specifically through both canonical Smad-dependent pathways (TGF-β/BMP ligands, receptors and Smads) and non-canonical Smad-independent signaling pathway (e.g. p38 mitogen-activated protein kinase pathway, MAPK). Following TGF-β/BMP induction, both the Smad and p38 MAPK pathways converge at the Runx2 gene to control mesenchymal precursor cell differentiation. The coordinated activity of Runx2 and TGF-β/BMP-activated Smads is critical for formation of the skeleton. Recent advances in molecular and genetic studies using gene targeting in mice enable a better understanding of TGF-β/BMP signaling in bone and in the signaling networks underlying osteoblast differentiation and bone formation. This review summarizes the recent advances in our understanding of TGF-β/BMP signaling in bone from studies of genetic mouse models and human diseases caused by the disruption of TGF-β/BMP signaling. This review also highlights the different modes of cross-talk between TGF-β/BMP signaling and the signaling pathways of MAPK, Wnt, Hedgehog, Notch, and FGF in osteoblast differentiation and bone formation. PMID:22298955

  15. Formation of hollow bone-like morphology of calcium carbonate on surfactant/polymer templates

    NASA Astrophysics Data System (ADS)

    Mantilaka, M. M. M. G. P. G.; Pitawala, H. M. T. G. A.; Rajapakse, R. M. G.; Karunaratne, D. G. G. P.; Upul Wijayantha, K. G.

    2014-04-01

    Novel hollow, bone-like structures of Precipitated Calcium Carbonate (PCC) are fabricated, for the first time, starting from naturally occurring dolomite. The hollow, bone-like structures are prepared by precipitating calcium carbonate on self-assembled poly(acrylic acid)/cetyltrimethylammonium chloride (PAA/CTAC) template. Fourier Transform Infrared Spectroscopy (FT-IR), X-ray diffraction (XRD), Transmission Electron Microscopy (TEM) and Field Emission Scanning Electron Microscopic (FE-SEM) studies reveal that the bone-like structure is composed of Amorphous Calcium Carbonate (ACC) nanoparticles in the center and calcite nanoparticles at the edges. Bone-like PCC particles are in particle length of 2-3 μm and particle width of 1 μm. The internal hollow structures of bone-like particles are observed from TEM images. As identified by FE-SEM images, the bone-like structure has been formed through the crystal growth of initially formed ACC nanoparticles. The ACC particles are stabilized in the center while the calcite crystals have been grown from the ACC toward the edges of the structure to form a bone-like morphology. We also propose a possible mechanism for the formation of hollow bone-like PCC in this study. The fabricated hollow, bone-like PCC has potential applications in the preparation of release systems such as drugs, cosmetics and pigments.

  16. Sirt1 is involved in decreased bone formation in aged apolipoprotein E-deficient mice

    PubMed Central

    Hong, Wei; Xu, Xiao-ya; Qiu, Zhao-hui; Gao, Jian-jun; Wei, Zhan-ying; Zhen, Li; Zhang, Xiao-li; Ye, Zhi-bing

    2015-01-01

    Aim: Apolipoprotein E (ApoE) plays an important role in the transport and metabolism of lipids. Recent studies show that bone mass is increased in young apoE−/− mice. In this study we investigated the bone phenotype and metabolism in aged apoE−/− mice. Methods: Femurs and tibias were collected from 18- and 72-week-old apoE−/− mice and their age-matched wild-type (WT) littermates, and examined using micro-CT and histological analysis. Serum levels of total cholesterol, oxidized low-density lipoprotein (ox-LDL) and bone turnover markers were measured. Cultured bone mesenchymal stem cells (BMSCs) from tibias and femurs of 18-week-old apoE−/− mice were used in experiments in vitro. The expression levels of Sirt1 and Runx2 in bone tissue and BMSCs were measured using RT-PCR and Western blot analysis. Results: Compared with age-matched WT littermates, young apoE−/− mice exhibited high bone mass with increased bone formation, accompanied by higher serum levels of bone turnover markers OCN and TRAP5b, and higher expression levels of Sirt1, Runx2, ALP and OCN in bone tissue. In contrast, aged apoE−/− mice showed reduced bone formation and lower bone mass relative to age-matched WT mice, accompanied by lower serum OCN levels, and markedly reduced expression levels of Sirt1, Runx2, ALP and OCN in bone tissue. After BMSCs were exposed to ox-LDL (20 μg/mL), the expression of Sirt1 and Runx2 proteins was significantly increased at 12 h, and then decreased at 72 h. Treatment with the Sirt1 inhibitor EX527 (10 μmol/L) suppressed the expression of Runx2, ALP and OCN in BMSCs. Conclusion: In contrast to young apoE−/− mice, aged apoE−/− mice showe lower bone mass than age-matched WT mice. Long-lasting exposure to ox-LDL decreases the expression of Sirt1 and Runx2 in BMSCs, which may explain the decreased bone formation in aged apoE−/− mice. PMID:26592520

  17. Bone Niches, Hematopoietic Stem Cells, and Vessel Formation

    PubMed Central

    Tamma, Roberto; Ribatti, Domenico

    2017-01-01

    Bone marrow (BM) is a source of hematopoietic stem cells (HSCs). HSCs are localized in both the endosteum, in the so-called endosteal niche, and close to thin-walled and fenestrated sinusoidal vessel in the center of BM, in the so-called vascular niche. HSCs give rise to all types of mature blood cells through a process finely controlled by numerous signals emerging from the bone marrow niches where HSCs reside. This review will focus on the description of the role of BM niches in the control of the fate of HSCs and will also highlight the role of the BM niches in the regulation of vasculogenesis and angiogenesis. Moreover, alterations of the signals in niche microenvironment are involved in many aspects of tumor progression and vascularization and further knowledge could provide the basis for the development of new therapeutic strategies. PMID:28098778

  18. Bone formation: The rules for fabricating a composite ceramic

    SciTech Connect

    Caplan, A.I. )

    1990-01-01

    Bone, teeth and shells are complex composite ceramics which are fabricated at low temperature by living organisms. The detailed understanding of this fabrication process is required if we are to attempt to mimic this low temperature assembly process. The guiding principles and major components are outlined with the intent of establishing non-vital fabrication schemes to form a complex composite ceramic consisting of an organix matrix inorganic crystalline phase. 19 refs.

  19. Collagen modifications in postmenopausal osteoporosis: advanced glycation endproducts may affect bone volume, structure and quality.

    PubMed

    Willett, Thomas L; Pasquale, Julia; Grynpas, Marc D

    2014-09-01

    The classic model of postmenopausal osteoporosis (PM-OP) starts with the depletion of estrogen, which in turn stimulates imbalanced bone remodeling, resulting in loss of bone mass/volume. Clinically, this leads to fractures because of structural weakness. Recent work has begun to provide a more complete picture of the mechanisms of PM-OP involving oxidative stress and collagen modifications known as advanced glycation endproducts (AGEs). On one hand, AGEs may drive imbalanced bone remodeling through signaling mediated by the receptor for AGEs (RAGE), stimulating resorption and inhibiting formation. On the other hand, AGEs are associated with degraded bone material quality. Oxidative stress promotes the formation of AGEs, inhibits normal enzymatically derived crosslinking and can degrade collagen structure, thereby reducing fracture resistance. Notably, there are multiple positive feedback loops that can exacerbate the mechanisms of PM-OP associated with oxidative stress and AGEs. Anti-oxidant therapies may have the potential to inhibit the oxidative stress based mechanisms of this disease.

  20. Enhanced Control of In Vivo Bone Formation with Surface Functionalized Alginate Microbeads Incorporating Heparin and Human Bone Morphogenetic Protein-2

    PubMed Central

    Abbah, Sunny Akogwu; Liu, Jing; Goh, James Cho Hong

    2013-01-01

    In this study, we tested the hypothesis that a surface functionalization delivery platform incorporating heparin onto strontium alginate microbeads surfaces would convert this “naive carriers” into “mini-reservoirs” for localized in vivo delivery of recombinant human bone morphogenetic protein-2 (rhBMP-2) that will induce functional bone regeneration. In vitro evaluation confirmed that (1) heparin incorporation could immobilize and prolong rhBMP-2 release for approximately 3 weeks; (2) a significant decrease (p<0.01) in rhBMP-2 burst release is attainable depending on initial protein load; and (3) rhBMP-2 released from surface functionalized microbeads retained bioactivity and stimulated higher alkaline phosphatase activity in cultured C2C12 cells when compared with daily administration of fresh bolus rhBMP-2. Subsequently, surface functionalized microbeads were used for in vivo delivery of rhBMP-2 at local sites of posterolateral spinal fusion surgery in rats. The microbeads were loaded into the pores of medical-grade polyepsilone caprolactone-tricalcium phosphate scaffolds before implantation. Results revealed robust bone formation and a biomechanically solid fusion after 6 weeks. When compared with a control group consisting of an equivalent amount of rhBMP-2 that was directly adsorbed onto bare-surfaced microbeads with no heparin, a 5.3-fold increase in bone volume fraction and a 2.6-fold increase in bending stiffness (flexion/extension) were observed. When compared with collagen sponge carriers of rhBMP-2, a 1.5-fold and a 1.3-fold increase in bone volume fraction and bending stiffness were observed, respectively. More importantly, 3D micro-computed tomography images enabled the visualization of a well-contained newly formed bone at ipsilateral implant sites with surface functionalized rhBMP-2 delivery. This was absent with collagen sponge carriers where newly formed bone tissue was poorly contained and crossed over the posterior midline to

  1. Low-Level Mechanical Vibrations can Reduce Bone Resorption and Enhance Bone Formation in the Growing Skeleton

    SciTech Connect

    Xie,L.; Jacobsen, J.; Busa, B.; Donahue, L.; Miller, L.; Rubin, C.; Judex, S.

    2006-01-01

    Short durations of extremely small magnitude, high-frequency, mechanical stimuli can promote anabolic activity in the adult skeleton. Here, it is determined if such signals can influence trabecular and cortical formative and resorptive activity in the growing skeleton, if the newly formed bone is of high quality, and if the insertion of rest periods during the loading phase would enhance the efficacy of the mechanical regimen. Eight-week-old female BALB/cByJ mice were divided into four groups, baseline control (n = 8), age-matched control (n = 10), whole-body vibration (WBV) at 45 Hz (0.3 g) for 15 min day{sup -1} (n = 10), and WBV that were interrupted every second by 10 of rest (WBV-R, n = 10). In vivo strain gaging of two additional mice indicated that the mechanical signal induced strain oscillations of approximately 10 microstrain on the periosteal surface of the proximal tibia. After 3 weeks of WBV, applied for 15 min each day, osteoclastic activity in the trabecular metaphysis and epiphysis of the tibia was 33% and 31% lower (P < 0.05) than in age-matched controls. Bone formation rates (BFR{center_dot}BS{sup -1}) on the endocortical surface of the metaphysis were 30% greater (P < 0.05) in WBV than in age-matched control mice but trabecular and middiaphyseal BFR were not significantly altered. The insertion of rest periods (WBV-R) failed to potentiate the cellular effects. Three weeks of either WBV or WBV-R did not negatively influence body mass, bone length, or chemical bone matrix properties of the tibia. These data indicate that in the growing skeleton, short daily periods of extremely small, high-frequency mechanical signals can inhibit trabecular bone resorption, site specifically attenuate the declining levels of bone formation, and maintain a high level of matrix quality. If WBV prove to be efficacious in the growing human skeleton, they may be able to provide the basis for a non-pharmacological and safe means to increase peak bone mass and, ultimately

  2. Fluoride-Induced Oxidative and Inflammatory Stress in Osteosarcoma Cells: Does It Affect Bone Development Pathway?

    PubMed

    Gandhi, Deepa; Naoghare, Pravin K; Bafana, Amit; Kannan, Krishnamurthi; Sivanesan, Saravanadevi

    2017-01-01

    Oxidative stress is reported to negatively affect osteoblast cells. Present study reports oxidative and inflammatory signatures in fluoride-exposed human osteosarcoma (HOS) cells, and their possible association with the genes involved in osteoblastic differentiation and bone development pathways. HOS cells were challenged with sublethal concentration (8 mg/L) of sodium fluoride for 30 days and analyzed for transcriptomic expression. In total, 2632 transcripts associated with several biological processes were found to be differentially expressed. Specifically, genes involved in oxidative stress, inflammation, osteoblastic differentiation, and bone development pathways were found to be significantly altered. Variation in expression of key genes involved in the abovementioned pathways was validated through qPCR. Expression of serum amyloid A1 protein, a key regulator of stress and inflammatory pathways, was validated through western blot analysis. This study provides evidence that chronic oxidative and inflammatory stress may be associated with the fluoride-induced impediment in osteoblast differentiation and bone development.

  3. Geochemical and mineralogical studies of dinosaur bone from the Morrison Formation at Dinosaur Ridge

    USGS Publications Warehouse

    Modreski, P.J.

    2001-01-01

    The dinosaur bones first discovered in 1877 in the Upper Jurassic Morrison Formation at Morrison, Colorado were the first major find of dinosaur skeletons in the western U.S. and led to the recognition of four new dinosaur genera (Apatosaurus, Allosaurus, Diplodocus, and Stegosaurus). Eight articles dealing with these bones which appeared as research reports in the annual reports of the Friends of Dinosaur Ridge from 1990-1999 are condensed and summarized with some additional comments. Two of the articles are about the mineralogy and preservation of the bones; two are about the physical description of the bone occurrence; two are about the history of the site, and two are about use of novel instrumental methods (ground-penetrating radar and a directional scintillometer) to search for new bones.

  4. Permian Bone Spring formation: Sandstone play in the Delaware basin. Part I - slope

    SciTech Connect

    Montgomery, S.L.

    1997-08-01

    New exploration in the Permian (Leonardian) Bone Spring formation has indicated regional potential in several sandstone sections across portions of the northern Delaware basin. Significant production has been established in the first, second, and third Bone Spring sandstones, as well as in a new reservoir interval, the Avalon sandstone, above the first Bone Spring sandstone. These sandstones were deposited as submarine-fan systems within the northern Delaware basin during periods of lowered sea level. The Bone Spring as a whole consists of alternating carbonate and siliciclastic intervals representing the downdip equivalents to thick Abo-Yeso/Wichita-Clear Fork carbonate buildups along the Leonardian shelf margin. Hydrocarbon exploration in the Bone Spring has traditionally focused on debris-flow carbonate deposits restricted to the paleoslope. Submarine-fan systems, in contrast, extend a considerable distance basinward of these deposits and have been recently proven productive as much as 40-48 km south of the carbonate trend.

  5. PDGF in bone formation and regeneration: new insights into a novel mechanism involving MSCs.

    PubMed

    Caplan, Arnold I; Correa, Diego

    2011-12-01

    With the identification of mesenchymal stem cells (MSCs) as pericytes, the details of bone formation, regeneration, and repair take on new meaning. Growth factors and other signaling molecules together with MSCs play important roles in these bone fabrication processes. However, the interaction of these cellular healing components is not completely understood. The formation of new vasculature is critical to regeneration and repair as both the driver and orientor of new bone formation. In this context, MSCs are proposed to be largely derived from pericytes associated with the vasculature. A comprehensive perspective is presented in which signaling molecules such as PDGF take on new significance in the vasculature-pericyte-MSC-osteoblast dynamics. Current data suggest that PDGF could function as a central connector between the cellular components and contributors of the osteoblast differentiation program. The inference is that PDGF could function at sites of injury to mobilize the pericytes from their abluminal location, stimulate mitotic expansion of these cells and help organize them. In this way, PDGF both contributes to the osteogenic lineage and helps to stabilize newly forming vessels that act to drive the multistep, multicomponent cascade of new bone formation. This thesis explains how PDGF functions as a powerful therapeutic agent for bone formation and repair.

  6. Inhibitor of DASH proteases affects expression of adhesion molecules in osteoclasts and reduces myeloma growth and bone disease.

    PubMed

    Pennisi, Angela; Li, Xin; Ling, Wen; Khan, Sharmin; Gaddy, Dana; Suva, Larry J; Barlogie, Bart; Shaughnessy, John D; Aziz, Nazneen; Yaccoby, Shmuel

    2009-06-01

    Dipeptidyl peptidase (DPP) IV activity and/or structure homologues (DASH) are serine proteases implicated in tumourigenesis. We previously found that a DASH protease, fibroblast activation protein (FAP), was involved in osteoclast-induced myeloma growth. Here we further demonstrated expression of various adhesion molecules in osteoclasts cultured alone or cocultured with myeloma cells, and tested the effects of DASH inhibitor, PT-100, on myeloma cell growth, bone disease, osteoclast differentiation and activity, and expression of adhesion molecules in osteoclasts. PT-100 had no direct effects on viability of myeloma cells or mature osteoclasts, but significantly reduced survival of myeloma cells cocultured with osteoclasts. Real-time PCR array for 85 adhesion molecules revealed upregulation of 17 genes in osteoclasts after coculture with myeloma cells. Treatment of myeloma/osteoclast cocultures with PT-100 significantly downregulated 18 of 85 tested genes in osteoclasts, some of which are known to play roles in tumourigenesis and osteoclastogenesis. PT-100 also inhibited osteoclast differentiation and subsequent pit formation. Resorption activity of mature osteoclasts and differentiation of osteoblasts were not affected by PT-100. In primary myelomatous severe combined immunodeficient (SCID)-hu mice PT-100 reduced osteoclast activity, bone resorption and tumour burden. These data demonstrated that DASH proteases are involved in myeloma bone disease and tumour growth.

  7. Factors affecting directional migration of bone marrow mesenchymal stem cells to the injured spinal cord.

    PubMed

    Xia, Peng; Pan, Su; Cheng, Jieping; Yang, Maoguang; Qi, Zhiping; Hou, Tingting; Yang, Xiaoyu

    2014-09-15

    Microtubule-associated protein 1B plays an important role in axon guidance and neuronal migration. In the present study, we sought to discover the mechanisms underlying microtubule-associated protein 1B mediation of axon guidance and neuronal migration. We exposed bone marrow mesenchymal stem cells to okadaic acid or N-acetyl-D-erythro-sphingosine (an inhibitor and stimulator, respectively, of protein phosphatase 2A) for 24 hours. The expression of the phosphorylated form of type I microtubule-associated protein 1B in the cells was greater after exposure to okadaic acid and lower after N-acetyl-D-erythro-sphingosine. We then injected the bone marrow mesenchymal stem cells through the ear vein into rabbit models of spinal cord contusion. The migration of bone marrow mesenchymal stem cells towards the injured spinal cord was poorer in cells exposed to okadaic acid- and N-acetyl-D-erythro-sphingosine than in non-treated bone marrow mesenchymal stem cells. Finally, we blocked phosphatidylinositol 3-kinase (PI3K) and extracellular signal-regulated kinase 1/2 (ERK1/2) pathways in rabbit bone marrow mesenchymal stem cells using the inhibitors LY294002 and U0126, respectively. LY294002 resulted in an elevated expression of phosphorylated type I microtubule-associated protein 1B, whereas U0126 caused a reduction in expression. The present data indicate that PI3K and ERK1/2 in bone marrow mesenchymal stem cells modulate the phosphorylation of microtubule-associated protein 1B via a cross-signaling network, and affect the migratory efficiency of bone marrow mesenchymal stem cells towards injured spinal cord.

  8. Space Maintenance and New Bone Formation with Polyurethane Biocomposites in a Canine Saddle Defect

    DTIC Science & Technology

    2014-05-01

    osteoblast differentiation, and enhance new bone formation. Biodegradable polyurethane (PUR) biocomposites containing allograft bone particles are...biocomposites with two doses of rhBMP-2 to heal saddle defects in the canine mandible. Methods: The biodegradable polyurethane was synthesized from...mm mesiodistal. The biocomposite was shaped through the creation of a pocket of soft tissue into which the composite could be injected (Fig 1

  9. Clinical factors affecting pathological fracture and healing of unicameral bone cysts

    PubMed Central

    2014-01-01

    Background Unicameral bone cyst (UBC) is the most common benign lytic bone lesion seen in children. The aim of this study is to investigate clinical factors affecting pathological fracture and healing of UBC. Methods We retrospectively reviewed 155 UBC patients who consulted Nagoya musculoskeletal oncology group hospitals in Japan. Sixty of the 155 patients had pathological fracture at presentation. Of 141 patients with follow-up periods exceeding 6 months, 77 were followed conservatively and 64 treated by surgery. Results The fracture risk was significantly higher in the humerus than other bones. In multivariate analysis, ballooning of bone, cyst in long bone, male sex, thin cortical thickness and multilocular cyst were significant adverse prognostic factors for pathological fractures at presentation. The healing rates were 30% and 83% with observation and surgery, respectively. Multivariate analysis revealed that fracture at presentation and history of biopsy were good prognostic factors for healing of UBC in patients under observation. Conclusion The present results suggest that mechanical disruption of UBC such as fracture and biopsy promotes healing, and thus watchful waiting is indicated in these patients, whereas patients with poor prognostic factors for fractures should be considered for surgery. PMID:24884661

  10. Dietary calcium restriction affects mesenchymal stem cell activity and bone development in neonatal pigs.

    PubMed

    Mahajan, Avanika; Alexander, Lindsey S; Seabolt, Brynn S; Catrambone, Daniel E; McClung, James P; Odle, Jack; Pfeiler, T Wayne; Loboa, Elizabeth G; Stahl, Chad H

    2011-03-01

    The effects of dietary calcium (Ca) deficiency on skeletal integrity are well characterized in growing and mature mammals; however, less is known about Ca nutrition during the neonatal period. In this study, we examined the effects of neonatal Ca nutrition on bone integrity, endocrine hormones, and mesenchymal stem cell (MSC) activity. Neonatal pigs (24 ± 6 h of age) received either a Ca-adequate (1.2 g/100 g) or an ~40% Ca-deficient diet for 18 d. Ca deficiency reduced (P < 0.05) bone flexural strength and bone mineral density without major differences in plasma indicators of Ca status. There were no meaningful differences in plasma Ca, phosphate (PO(4)), parathyroid hormone, or 1,25-dihydroxycholecalciferol due to Ca nutrition throughout the study. Calcium deficiency also reduced (P < 0.05) the in vivo proliferation of MSC by ~50%. In vitro studies utilizing homologous sera demonstrated that MSC activity was affected (P < 0.05) by both the Ca status of the pig and the sera as well as by their interaction. The results indicate that neonatal Ca nutrition is crucial for bone integrity and suggest that early-life Ca restriction may have long-term effects on bone integrity via programming of MSC.

  11. The effect of enamel matrix derivative (Emdogain) on bone formation: a systematic review.

    PubMed

    Rathe, Florian; Junker, Rüdiger; Chesnutt, Betsy M; Jansen, John A

    2009-09-01

    This systematic review focused on the question, if and to what extent enamel matrix derivative (Emdogain) [EMD]) promotes the regeneration of bone. The influence of combinations with other biomaterials was additionally evaluated. Twenty histomorphometric studies were included in this systematic review. Main results of the reviewed articles were (i) guide tissue regeneration (GTR) of infrabony defects seems to result in a higher degree of bone regeneration compared to treatment with EMD; (ii) combined therapy (GTR + EMD) of infrabony defects might not lead to better results than GTR therapy alone; (iii) there seems to be no additional benefit of combined therapy (GTR + EMD) in furcation defects over GTR therapy alone; (iv) EMD seems to lead to more bone regeneration of infrabony defects compared to open flap debridement; (v) however, EMD application might result in more bone formation when applied in supporting defects compared to nonsupporting defects; and (vi) EMD does not seem to promote external jaw/parietal bone formation in the titanium capsule model. The results of one study that suggest that EMD increases the initial growth of trabecular bone around endosseous implants by new bone induction need to be confirmed by additional research.

  12. WNT7B promotes bone formation in part through mTORC1.

    PubMed

    Chen, Jianquan; Tu, Xiaolin; Esen, Emel; Joeng, Kyu Sang; Lin, Congxin; Arbeit, Jeffrey M; Rüegg, Markus A; Hall, Michael N; Ma, Liang; Long, Fanxin

    2014-01-01

    WNT signaling has been implicated in both embryonic and postnatal bone formation. However, the pertinent WNT ligands and their downstream signaling mechanisms are not well understood. To investigate the osteogenic capacity of WNT7B and WNT5A, both normally expressed in the developing bone, we engineered mouse strains to express either protein in a Cre-dependent manner. Targeted induction of WNT7B, but not WNT5A, in the osteoblast lineage dramatically enhanced bone mass due to increased osteoblast number and activity; this phenotype began in the late-stage embryo and intensified postnatally. Similarly, postnatal induction of WNT7B in Runx2-lineage cells greatly stimulated bone formation. WNT7B activated mTORC1 through PI3K-AKT signaling. Genetic disruption of mTORC1 signaling by deleting Raptor in the osteoblast lineage alleviated the WNT7B-induced high-bone-mass phenotype. Thus, WNT7B promotes bone formation in part through mTORC1 activation.

  13. Kartogenin with PRP promotes the formation of fibrocartilage zone in the tendon-bone interface.

    PubMed

    Zhou, Yiqin; Zhang, Jianying; Yang, Jinsong; Narava, Manoj; Zhao, Guangyi; Yuan, Ting; Wu, Haishan; Zheng, Nigel; Hogan, MaCalus V; Wang, James H-C

    2017-01-27

    Treatment of tendon-bone junction injuries is a challenge because tendon-bone interface often heals poorly and the fibrocartilage zone, which reduces stress concentration, at the interface is not formed. In this study, we used a compound called kartogenin (KGN) with platelet-rich plasma (PRP) to induce the formation of fibrocartilage zone in a rat tendon graft-bone tunnel model. The experimental rats received KGN-PRP or PRP injections in the tendon graft-bone tunnel interface. The control group received saline. After 4, 8 and 12 weeks, Safranin O staining of the tendon graft-bone tunnels revealed abundant proteoglycans in the KGN-PRP group indicating the formation of cartilage-like transition zone. Immunohistochemical and immuno-fluorescence staining revealed collagen types I (Col-I) and II (Col-II) in the newly formed fibrocartilage zone. Both fibrocartilage zone formation and maturation were healing time dependent. In contrast, the PRP and saline control groups had no cartilage-like tissues and minimal Col-I and Col-II staining. Some gaps were also present in the saline control group. Finally, pull-out strength in the KGN-PRP-treated group at 8 weeks was 1.4-fold higher than the PRP-treated group and 1.6-fold higher than the saline control group. These findings indicate that KGN, with PRP as a carrier, promotes the formation of fibrocartilage zone between the tendon graft and bone interface. Thus, KGN-PRP may be used as a convenient cell-free therapy in clinics to promote fibrocartilage zone formation in rotator calf repair and anterior cruciate ligament reconstruction, thereby enhancing the mechanical strength of the tendon-bone interface and hence the clinical outcome of these procedures. Copyright © 2017 John Wiley & Sons, Ltd.

  14. cAMP/PKA pathway activation in human mesenchymal stem cells in vitro results in robust bone formation in vivo.

    PubMed

    Siddappa, Ramakrishnaiah; Martens, Anton; Doorn, Joyce; Leusink, Anouk; Olivo, Cristina; Licht, Ruud; van Rijn, Linda; Gaspar, Claudia; Fodde, Riccardo; Janssen, Frank; van Blitterswijk, Clemens; de Boer, Jan

    2008-05-20

    Tissue engineering of large bone defects is approached through implantation of autologous osteogenic cells, generally referred to as multipotent stromal cells or mesenchymal stem cells (MSCs). Animal-derived MSCs successfully bridge large bone defects, but models for ectopic bone formation as well as recent clinical trials demonstrate that bone formation by human MSCs (hMSCs) is inadequate. The expansion phase presents an attractive window to direct hMSCs by pharmacological manipulation, even though no profound effect on bone formation in vivo has been described so far using this approach. We report that activation of protein kinase A elicits an immediate response through induction of genes such as ID2 and FosB, followed by sustained secretion of bone-related cytokines such as BMP-2, IGF-1, and IL-11. As a consequence, PKA activation results in robust in vivo bone formation by hMSCs derived from orthopedic patients.

  15. Differential gene expression from microarray analysis distinguishes woven and lamellar bone formation in the rat ulna following mechanical loading.

    PubMed

    McKenzie, Jennifer A; Bixby, Elise C; Silva, Matthew J

    2011-01-01

    Formation of woven and lamellar bone in the adult skeleton can be induced through mechanical loading. Although much is known about the morphological appearance and structural properties of the newly formed bone, the molecular responses to loading are still not well understood. The objective of our study was to use a microarray to distinguish the molecular responses between woven and lamellar bone formation induced through mechanical loading. Rat forelimb loading was completed in a single bout to induce the formation of woven bone (WBF loading) or lamellar bone (LBF loading). A set of normal (non-loaded) rats were used as controls. Microarrays were performed at three timepoints after loading: 1 hr, 1 day and 3 days. Confirmation of microarray results was done for a select group of genes using quantitative real-time PCR (qRT-PCR). The micorarray identified numerous genes and pathways that were differentially regulated for woven, but not lamellar bone formation. Few changes in gene expression were evident comparing lamellar bone formation to normal controls. A total of 395 genes were differentially expressed between formation of woven and lamellar bone 1 hr after loading, while 5883 and 5974 genes were differentially expressed on days 1 and 3, respectively. Results suggest that not only are the levels of expression different for each type of bone formation, but that distinct pathways are activated only for woven bone formation. A strong early inflammatory response preceded an increase in angiogenic and osteogenic gene expression for woven bone formation. Furthermore, at later timepoints there was evidence of bone resorption after WBF loading. In summary, the vast coverage of the microarray offers a comprehensive characterization of the early differences in expression between woven and lamellar bone formation.

  16. Involvement of Zn Depletion in Cd-Induced Toxicity on Prenatal Bone Formation in Rat.

    PubMed

    Boughammoura, Sana; Chemek, Marouane; Mimouna, Safa Ben; Banni, Mohamed; Messaoudi, Imed

    2017-03-06

    This study explored the potential toxicity of Cd on the Zn bone depletion in prenatal bone formation. Female rats received either tap water, Cd, Zn, or Cd + Zn in their drinking water during gestation, and some markers of bone formation were studied in their fetuses removed at the 20th day of pregnancy (GD20). Cd exposure induced maternal hypozincemia and Zn depletion in the femur of the fetuses. A striking inhibition of bone formation in fetuses, expressed by decreases in femur length, width, and area, by the shortening of diaphysis, and by a decrease in length and area of distal and proximal proliferative zones, was observed in fetuses from Cd-exposed mothers. At the molecular level, Cd caused upregulation of MT-1 and ZIP2 genes and significantly depressed the expression of the ZnT5, colα1, osteocalcin, and ALP genes in the femur. Interestingly, Zn treatment ameliorated the Cd-induced maternal hypozincemia and femoral changes and partially restored the normal histomorphometry of the femur. These results suggest that the observed toxic effects of Cd are, at least in part, mediated by the disruption of maternal Zn metabolism during pregnancy leading to Zn depletion and thus to perturbation of prenatal bone formation.

  17. Decreased Bone Formation and Osteopenia in Lamin A/C-Deficient Mice

    PubMed Central

    Vidal, Christopher; McCorquodale, Thomas; Herrmann, Markus; Fatkin, Diane; Duque, Gustavo

    2011-01-01

    Age-related bone loss is associated with changes in bone cellularity with characteristically low levels of osteoblastogenesis. The mechanisms that explain these changes remain unclear. Although recent in vitro evidence has suggested a new role for proteins of the nuclear envelope in osteoblastogenesis, the role of these proteins in bone cells differentiation and bone metabolism in vivo remains unknown. In this study, we used the lamin A/C null (Lmna−/−) mice to identify the role of lamin A/C in bone turnover and bone structure in vivo. At three weeks of age, histological and micro computed tomography measurements of femurs in Lmna−/− mice revealed a significant decrease in bone mass and microarchitecture in Lmna−/− mice as compared with their wild type littermates. Furthermore, quantification of cell numbers after normalization with bone surface revealed a significant reduction in osteoblast and osteocyte numbers in Lmna−/− mice compared with their WT littermates. In addition, Lmna−/− mice have significantly lower osteoclast number, which show aberrant changes in their shape and size. Finally, mechanistic analysis demonstrated that absence of lamin A/C is associated with increase expression of MAN-1 a protein of the nuclear envelope closely regulated by lamin A/C, which also colocalizes with Runx2 thus affecting its capacity as osteogenic transcription factor. In summary, these data clearly indicate that the presence of lamin A/C is necessary for normal bone turnover in vivo and that absence of lamin A/C induces low bone turnover osteopenia resembling the cellular changes of age-related bone loss. PMID:21547077

  18. In vitro evaluation of a fibrin gel antibiotic delivery system containing mesenchymal stem cells and vancomycin alginate beads for treating bone infections and facilitating bone formation.

    PubMed

    Hou, Tianyong; Xu, Jianzhong; Li, Qiang; Feng, Jianghua; Zen, Ling

    2008-07-01

    Bone infection and defects are two major problems that occur in the course of treating posttraumatic open bone fractures and osteomyelitis for which local antibiotic delivery is efficacious. Further, hemostasis is an essential treatment after removal of infected bones. Herein we report a new antibiotics delivery system made of vancomycin alginate beads embedded in a fibrin gel (Vanco-AB-FG) to treat bone infections, with the addition of bone marrow-derived mesenchymal stem cells (BMMSCs) seeded in the fibrin gel to promote bone formation. The proliferation of BMMSCs was measured under different conditions of three-dimensional (3D) gel or monolayer, with or without Vanco-AB; cells were labeled by enhanced green fluorescence protein, and their morphology and distribution were observed. The alkaline phosphatase (ALP) activity, real-time RT-PCR, and von Kossa staining were used for determining the osteogenic differentiation of BMMSCs. The concentrations of vancomycin resulting from the antibiotic delivery were determined; the antibiotic activity was evaluated by an assay with standard Staphylococcus aureus (ATCC 25923) as a biological target. The results showed that for Vanco-AB-FG, vancomycin concentrations remained above the breakpoint sensitivity for 22 days. The 3D culture within the gel and the addition of Vanco-AB affected the cell behavior. The morphology of BMMSCs within the 3D gel was different from that in monolayer. The proliferation of the cells within the 3D gel was lower than that in monolayer in early stage, but in later stage the number of BMMSCs in Vanco-AB-FG was similar to that in monolayer. The ALP activity was higher in the 3D gel, and the addition of Vanco-AB slightly increased ALP activity. The osteogenic gene expression levels of ALP, osteopontin, and alpha1 chain of collagen I were higher in the 3D gel than those in monolayer, and additional Vanco-AB could also increase their expression. The von Kossa staining showed that the deposition of

  19. Effects of designed PLLA and 50:50PLGA scaffold architectures on bone formation in vivo

    PubMed Central

    Saito, Eiji; Liao, Elly E.; Hu, Wei-Wen; Krebsbach, Paul H.; Hollister, Scott J.

    2015-01-01

    Biodegradable porous scaffolds have been investigated as an alternative approach to current metal, ceramic, and polymer bone graft substitutes for lost or damaged bone tissues. Although there have been many studies investigating the effects of scaffold architecture on bone formation, many of these scaffolds were fabricated using conventional methods, such as salt leaching and phase separation, and were constructed without designed architecture. To study the effects of both designed architecture and material on bone formation, we designed and fabricated three types of porous scaffold architecture from two biodegradable materials, poly (L-lactic acid) (PLLA) and 50:50Poly (lactic-co-glycolic acid) (PLGA) using image based design and indirect solid freeform fabrication techniques, seeded them with bone morphogenic protein-7 transduced human gingival fibroblasts and implanted them subcutaneously into mice for 4 and 8 weeks. Micro-computed tomography data confirmed that the fabricated porous scaffolds replicated the designed architectures. Histological analysis revealed that the 50:50PLGA scaffolds degraded and did not maintain their architecture after 4 weeks. The PLLA scaffolds maintained their architecture at both time points and showed improved bone ingrowth which followed the internal architecture of the scaffolds. Mechanical properties of both PLLA and 50:50PLGA scaffolds decreased, but PLLA scaffolds maintained greater mechanical properties than 50:50PLGA after implantation. The increase of mineralized tissue helped to support mechanical properties of bone tissue and scaffold constructs from 4 to 8 weeks. The results indicated the importance of choice of scaffold materials and computationally designed scaffolds to control tissue formation and mechanical properties for desired bone tissue regeneration. PMID:22162220

  20. Apoptosis-associated uncoupling of bone formation and resorption in osteomyelitis.

    PubMed

    Marriott, Ian

    2013-01-01

    The mechanisms underlying the destruction of bone tissue in osteomyelitis are only now being elucidated. While some of the tissue damage associated with osteomyelitis likely results from the direct actions of bacteria and infiltrating leukocytes, perhaps exacerbated by bacterial manipulation of leukocyte survival pathways, infection-induced bone loss predominantly results from an uncoupling of the activities of osteoblasts and osteoclasts. Bacteria or their products can directly increase osteoclast formation and activity, and the inflammatory milieu at sites of infection can further promote bone resorption. In addition, osteoclast activity is critically regulated by osteoblasts that can respond to bacterial pathogens and foster both inflammation and osteoclastogenesis. Importantly, bone loss during osteomyelitis is also brought about by a decline in new bone deposition due to decreased bone matrix synthesis and by increased rates of osteoblast apoptosis. Extracellular bacterial components may be sufficient to reduce osteoblast viability, but the causative agents of osteomyelitis are also capable of inducing continuous apoptosis of these cells by activating intrinsic and extrinsic cell death pathways to further uncouple bone formation and resorption. Interestingly, bacterial internalization appears to be required for maximal osteoblast apoptosis, and cytosolic inflammasome activation may act in concert with autocrine/paracrine death receptor-ligand signaling to induce cell death. The manipulation of apoptotic pathways in infected bone cells could be an attractive new means to limit inflammatory damage in osteomyelitis. However, the mechanism that is the most important in bacterium-induced bone loss has not yet been identified. Furthermore, it remains to be determined whether the host would be best served by preventing osteoblast cell death or by promoting apoptosis in infected cells.

  1. Apoptosis-associated uncoupling of bone formation and resorption in osteomyelitis

    PubMed Central

    Marriott, Ian

    2013-01-01

    The mechanisms underlying the destruction of bone tissue in osteomyelitis are only now being elucidated. While some of the tissue damage associated with osteomyelitis likely results from the direct actions of bacteria and infiltrating leukocytes, perhaps exacerbated by bacterial manipulation of leukocyte survival pathways, infection-induced bone loss predominantly results from an uncoupling of the activities of osteoblasts and osteoclasts. Bacteria or their products can directly increase osteoclast formation and activity, and the inflammatory milieu at sites of infection can further promote bone resorption. In addition, osteoclast activity is critically regulated by osteoblasts that can respond to bacterial pathogens and foster both inflammation and osteoclastogenesis. Importantly, bone loss during osteomyelitis is also brought about by a decline in new bone deposition due to decreased bone matrix synthesis and by increased rates of osteoblast apoptosis. Extracellular bacterial components may be sufficient to reduce osteoblast viability, but the causative agents of osteomyelitis are also capable of inducing continuous apoptosis of these cells by activating intrinsic and extrinsic cell death pathways to further uncouple bone formation and resorption. Interestingly, bacterial internalization appears to be required for maximal osteoblast apoptosis, and cytosolic inflammasome activation may act in concert with autocrine/paracrine death receptor-ligand signaling to induce cell death. The manipulation of apoptotic pathways in infected bone cells could be an attractive new means to limit inflammatory damage in osteomyelitis. However, the mechanism that is the most important in bacterium-induced bone loss has not yet been identified. Furthermore, it remains to be determined whether the host would be best served by preventing osteoblast cell death or by promoting apoptosis in infected cells. PMID:24392356

  2. In vivo stimulation of bone formation by aluminum and oxygen plasma surface-modified magnesium implants.

    PubMed

    Wong, Hoi Man; Zhao, Ying; Tam, Vivian; Wu, Shuilin; Chu, Paul K; Zheng, Yufeng; To, Michael Kai Tsun; Leung, Frankie K L; Luk, Keith D K; Cheung, Kenneth M C; Yeung, Kelvin W K

    2013-12-01

    A newly developed magnesium implant is used to stimulate bone formation in vivo. The magnesium implant after undergoing dual aluminum and oxygen plasma implantation is able to suppress rapid corrosion, leaching of magnesium ions, as well as hydrogen gas release from the biodegradable alloy in simulated body fluid (SBF). No released aluminum is detected from the SBF extract and enhanced corrosion resistance properties are confirmed by electrochemical tests. In vitro studies reveal enhanced growth of GFP mouse osteoblasts on the aluminum oxide coated sample, but not on the untreated sample. In addition to that a small amount (50 ppm) of magnesium ions can enhance osteogenic differentiation as reported previously, our present data show a low concentration of hydrogen can give rise to the same effect. To compare the bone volume change between the plasma-treated magnesium implant and untreated control, micro-computed tomography is performed and the plasma-treated implant is found to induce significant new bone formation adjacent to the implant from day 1 until the end of the animal study. On the contrary, bone loss is observed during the first week post-operation from the untreated magnesium sample. Owing to the protection offered by the Al2O3 layer, the plasma-treated implant degrades more slowly and the small amount of released magnesium ions stimulate new bone formation locally as revealed by histological analyses. Scanning electron microscopy discloses that the Al2O3 layer at the bone-implant interface is still present two months after implantation. In addition, no inflammation or tissue necrosis is observed from both treated and untreated implants. These promising results suggest that the plasma-treated magnesium implant can stimulate bone formation in vivo in a minimal invasive way and without causing post-operative complications.

  3. Improving Bone Formation in a Rat Femur Segmental Defect by Controlling Bone Morphogenetic Protein-2 Release

    DTIC Science & Technology

    2011-04-01

    delivered on a collagen sponge (INFUSE Bone Graft; Medtronic) has been approved by FDA for posterior-lateral spine fusions, tibial fractures, and sinus...area was defined by drawing a quadrilateral area using the periosteal corners of the four host cortices as points of reference. The relative areas of...section of an FR +BMP scaffold in Figure 8 (the ap- proximate boundary of the implant is denoted by the box) shows a mature and fully bridged periosteal

  4. Short-term vitamin A supplementation does not affect bone turnover in men.

    PubMed

    Kawahara, Tisha N; Krueger, Diane C; Engelke, Jean A; Harke, Judy M; Binkley, Neil C

    2002-06-01

    Limited data in humans and animals indicate that excess vitamin A stimulates bone resorption and inhibits bone formation, effects that over time might lead to bone loss and fracture. Thus, it is possible that vitamin A supplementation is a currently unrecognized risk factor for the development of osteoporosis. To further evaluate this possibility, a prospective, randomized, single-blind study of vitamin A supplementation was conducted in 80 healthy men age 18-58 y. One half received 7576 microg (25,000 IU) of retinol palmitate daily with their evening meal; the others took a placebo. Blood was collected from fasting subjects and serum prepared at baseline and after 2, 4 and 6 wk of supplementation. Serum bone specific alkaline phosphatase (BSAP) and N-Telopeptide of type 1 collagen (NTx) were measured at all time points. Serum osteocalcin (Oc) was measured at baseline and after 6 wk of supplementation. BSAP, NTx and Oc did not differ between the supplemented and placebo-treated groups over the course of the study. In conclusion, short-term vitamin A supplementation at this dosage in healthy men does not alter serum markers of skeletal turnover. Thus, it is unlikely that short-term administration of vitamin A would contribute to the development of osteoporosis. Whether long-term vitamin A supplementation might have adverse skeletal effects remains to be determined.

  5. Inferior ectopic bone formation of mesenchymal stromal cells from adipose tissue compared to bone marrow: rescue by chondrogenic pre-induction.

    PubMed

    Brocher, J; Janicki, P; Voltz, P; Seebach, E; Neumann, E; Mueller-Ladner, U; Richter, W

    2013-11-01

    Human mesenchymal stromal cells derived from bone marrow (BMSC) and adipose tissue (ATSC) represent a valuable source of progenitor cells for cell therapy and tissue engineering. While ectopic bone formation is a standard activity of human BMSC on calcium phosphate ceramics, the bone formation capacity of human ATSC has so far been unclear. The objectives of this study were to assess the therapeutic potency of ATSC for bone formation in an ectopic mouse model and determine molecular differences by standardized comparison with BMSC. Although ATSC contained less CD146(+) cells, exhibited better proliferation and displayed similar alkaline phosphatase activity upon osteogenic in vitro differentiation, cells did not develop into bone-depositing osteoblasts on β-TCP after 8weeks in vivo. Additionally, ATSC expressed less BMP-2, BMP-4, VEGF, angiopoietin and IL-6 and more adiponectin mRNA, altogether suggesting insufficient osteochondral commitment and reduced proangiogenic activity. Chondrogenic pre-induction of ATSC/β-TCP constructs with TGF-β and BMP-6 initiated ectopic bone formation in >75% of samples. Both chondrogenic pre-induction and the osteoconductive microenvironment of β-TCP were necessary for ectopic bone formation by ATSC pointing towards a need for inductive conditions/biomaterials to make this more easily accessible cell source attractive for future applications in bone regeneration.

  6. Is bone formation induced by high-frequency mechanical signals modulated by muscle activity?

    PubMed

    Judex, S; Rubin, C T

    2010-03-01

    Bone formation and resorption are sensitive to both external loads arising from gravitational loading as well to internal loads generated by muscular activity. The question as to which of the two sources provides the dominant stimulus for bone homeostasis and new bone accretion is arguably tied to the specific type of activity and anatomical site but it is often assumed that, because of their purportedly greater magnitude, muscle loads modulate changes in bone morphology. High-frequency mechanical signals may provide benefits at low- (<1g) and high- (>1g) acceleration magnitudes. While the mechanisms by which cells perceive high-frequency signals are largely unknown, higher magnitude vibrations can cause large muscle loads and may therefore be sensed by pathways similar to those associated with exercise. Here, we review experimental data to examine whether vibrations applied at very low magnitudes may be sensed directly by transmittance of the signal through the skeleton or whether muscle activity modulates, and perhaps amplifies, the externally applied mechanical stimulus. Current data indicate that the anabolic and anti-catabolic effects of whole body vibrations on the skeleton are unlikely to require muscular activity to become effective. Even high-frequency signals that induce bone matrix deformations of far less than five microstrain can promote bone formation in the absence of muscular activity. This independence of cells on large strains suggests that mechanical interventions can be designed that are both safe and effective.

  7. Stimulatory effects of low-power laser irradiation on bone formation in vitro

    NASA Astrophysics Data System (ADS)

    Ozawa, Yasuhito; Shimizu, Noriyoshi; Mishima, Hiroyuki; Kariya, Genichiro; Yamaguchi, Masaru; Takiguchi, Hisashi; Iwasawa, Tadamasa; Abiko, Yoshimitsu

    1995-04-01

    The effect of low-power laser irradiation on bone formation in vitro were assessed. Osteoblast-like cells were isolated from rat calvariae of 21d rat fetuses. The cultured calvarial cells were irradiated with a low-power laser (830 nm, 60 mW) one time only or once daily for 21d at various energy doses (10.8-108 J/day). The number and the total area of mineralized bone modules that had developed in the culture dish on day 21 were evaluated. DNA content, alkaline phosphatase (ALP) activity and the amount of extra-cellular collagen were also measured. Calcium and phosphorus in bone nodules were examined with an X-ray microanalyzer. Laser irradiation significantly increased the number and the total area of bone nodules in a dose-dependent manner. Cell proliferation and ALP activity in the irradiation group were higher in the early and middle culture periods, while the collagen content was higher in the middle an late periods compared with the control. Calcium and phosphorus were both higher in the irradiation group. These findings indicate that laser irradiation may play a principal role in stimulating differentiation of osteoblasts during the early stage of the culture, resulting in increased bone formation through acceleration of bone nodule maturation.

  8. Bone metabolism and formation of mice bred in a 2G environment

    NASA Astrophysics Data System (ADS)

    Kita, S.; Iwasaki, K.; Onishi, R.; Fujisawa, M.; Kim, H.; Shibata, S.; Ito, M.

    2003-10-01

    The purpose of this study is to reveal the effect of chronic hypergravity exposure on the bone formation and the bone metabolism when mammals produce offspring in a 2G environment. We measured the length and width of the thighbone, the length of the pelvis, the width of the pelvic cavity and the width of the fourth cervical vertebra on the second (F2) and the third (F3) generation mice bred in a 2G environment every ten days from 20 days old to 60 days old in an experiment on bone formation. In an experiment on bone metabolism, we measured calcium and phosphorus in the bones of the F3 in the 2G group.Ratios of the thighbone length, pelvis length, pelvic cavity width, and fourth cervical vertebra width versus the body length were calculated.These ratios were higher in the 2G group than the control group during all measuring periods.Calcium and phosphorus concentrations in the thighbone and the lumbar vertebra were lower in the 2G group than in the control group. However, the calcium and phosphorus concentrations in the cervical vertebrae of the 2G group were higher. These results suggest that the influence of gravity load may vary in the bones.

  9. Evaluation of the parameters affecting bone temperature during drilling using a three-dimensional dynamic elastoplastic finite element model.

    PubMed

    Chen, Yung-Chuan; Tu, Yuan-Kun; Zhuang, Jun-Yan; Tsai, Yi-Jung; Yen, Cheng-Yo; Hsiao, Chih-Kun

    2017-03-28

    A three-dimensional dynamic elastoplastic finite element model was constructed and experimentally validated and was used to investigate the parameters which influence bone temperature during drilling, including the drill speed, feeding force, drill bit diameter, and bone density. Results showed the proposed three-dimensional dynamic elastoplastic finite element model can effectively simulate the temperature elevation during bone drilling. The bone temperature rise decreased with an increase in feeding force and drill speed, however, increased with the diameter of drill bit or bone density. The temperature distribution is significantly affected by the drilling duration; a lower drilling speed reduced the exposure duration, decreases the region of the thermally affected zone. The constructed model could be applied for analyzing the influence parameters during bone drilling to reduce the risk of thermal necrosis. It may provide important information for the design of drill bits and surgical drilling powers.

  10. Evidence of ectokinase-mediated phosphorylation of osteopontin and bone sialoprotein by osteoblasts during bone formation in vitro.

    PubMed Central

    Zhu, X; Luo, C; Ferrier, J M; Sodek, J

    1997-01-01

    Osteopontin (OPN) and bone sialoprotein (BSP) are phosphorylated glycoproteins that, together with osteonectin/secreted protein, acidic, rich in cysteine (SPARC) and osteocalcin, comprise the major non-collagen proteins of bone. Although phosphorylation of OPN and BSP, which is known to influence the biological properties of these proteins, has been shown to occur intracellularly, recent studies have demonstrated ectokinase activity in bone cell populations [Mikuni-Takagaki, Kakai, Satoyoshi, Kawano, Suzuki, Kawase and Saito (1995) J. Bone Miner. Res. 10, 231-241]. To determine whether OPN and BSP are phosphorylated by ectokinase activity we have used [gamma-32P]ATP and [gamma-32P]GTP as cell-impenetrable phosphate donors to analyse for ectokinase activity in osteoblastic UMR106.06 cells and fetal rat calvarial cells (FRCCs). By pulse-labelling confluent cells with radiolabelled nucleotides, the phosphorylation of endogenous and exogenously added OPN and BSP was demonstrated together with the labelling of a number of cell surface proteins. These phosphorylation reactions were inhibited by a cell-impermeable ectokinase inhibitor, K252b, and cell surface phosphorylation was also inhibited by exogenously added OPN and BSP substrates, indicating competition for the ectokinase enzyme. However, phosphorylation of OPN and BSP, both of which can mediate cell attachment through Arg-Gly-Asp (RGD) motifs, was not inhibited by an RGD peptide, suggesting that binding of OPN and BSP to cell surface integrins is not required. In similar experiments, ectokinase-mediated phosphorylation of OPN and BSP was demonstrated during mineralized tissue formation by FRCCs in vitro. These studies demonstrate that OPN and BSP secreted by bone cells are phosphorylated by a casein kinase II-like ectokinase present on the surface of osteoblastic cells. PMID:9169595

  11. Bone formation by three-dimensional stromal osteoblast culture in biodegradable polymer scaffolds

    NASA Technical Reports Server (NTRS)

    Ishaug, S. L.; Crane, G. M.; Miller, M. J.; Yasko, A. W.; Yaszemski, M. J.; Mikos, A. G.; McIntire, L. V. (Principal Investigator)

    1997-01-01

    Bone formation was investigated in vitro by culturing stromal osteoblasts in three-dimensional (3-D), biodegradable poly(DL-lactic-co-glycolic acid) foams. Three polymer foam pore sizes, ranging from 150-300, 300-500, and 500-710 microns, and two different cell seeding densities, 6.83 x 10(5) cells/cm2 and 22.1 x 10(5) cells/cm2, were examined over a 56-day culture period. The polymer foams supported the proliferation of seeded osteoblasts as well as their differentiated function, as demonstrated by high alkaline phosphatase activity and deposition of a mineralized matrix by the cells. Cell number, alkaline phosphatase activity, and mineral deposition increased significantly over time for all the polymer foams. Osteoblast foam constructs created by seeding 6.83 x 10(5) cells/cm2 on foams with 300-500 microns pores resulted in a cell density of 4.63 x 10(5) cells/cm2 after 1 day in culture; they had alkaline phosphatase activities of 4.28 x 10(-7) and 2.91 x 10(-6) mumol/cell/min on Days 7 and 28, respectively; and they had a cell density that increased to 18.7 x 10(5) cells/cm2 by Day 56. For the same constructs, the mineralized matrix reached a maximum penetration depth of 240 microns from the top surface of the foam and a value of 0.083 mm for mineralized tissue volume per unit of cross sectional area. Seeding density was an important parameter for the constructs, but pore size over the range tested did not affect cell proliferation or function. This study suggests the feasibility of using poly(alpha-hydroxy ester) foams as scaffolding materials for the transplantation of autogenous osteoblasts to regenerate bone tissue.

  12. Bone formation by three-dimensional stromal osteoblast culture in biodegradable polymer scaffolds.

    PubMed

    Ishaug, S L; Crane, G M; Miller, M J; Yasko, A W; Yaszemski, M J; Mikos, A G

    1997-07-01

    Bone formation was investigated in vitro by culturing stromal osteoblasts in three-dimensional (3-D), biodegradable poly(DL-lactic-co-glycolic acid) foams. Three polymer foam pore sizes, ranging from 150-300, 300-500, and 500-710 microns, and two different cell seeding densities, 6.83 x 10(5) cells/cm2 and 22.1 x 10(5) cells/cm2, were examined over a 56-day culture period. The polymer foams supported the proliferation of seeded osteoblasts as well as their differentiated function, as demonstrated by high alkaline phosphatase activity and deposition of a mineralized matrix by the cells. Cell number, alkaline phosphatase activity, and mineral deposition increased significantly over time for all the polymer foams. Osteoblast foam constructs created by seeding 6.83 x 10(5) cells/cm2 on foams with 300-500 microns pores resulted in a cell density of 4.63 x 10(5) cells/cm2 after 1 day in culture; they had alkaline phosphatase activities of 4.28 x 10(-7) and 2.91 x 10(-6) mumol/cell/min on Days 7 and 28, respectively; and they had a cell density that increased to 18.7 x 10(5) cells/cm2 by Day 56. For the same constructs, the mineralized matrix reached a maximum penetration depth of 240 microns from the top surface of the foam and a value of 0.083 mm for mineralized tissue volume per unit of cross sectional area. Seeding density was an important parameter for the constructs, but pore size over the range tested did not affect cell proliferation or function. This study suggests the feasibility of using poly(alpha-hydroxy ester) foams as scaffolding materials for the transplantation of autogenous osteoblasts to regenerate bone tissue.

  13. Repeated freeze-thaw cycles reduce the survival rate of osteocytes in bone-tendon constructs without affecting the mechanical properties of tendons.

    PubMed

    Suto, Kaori; Urabe, Ken; Naruse, Kouji; Uchida, Kentaro; Matsuura, Terumasa; Mikuni-Takagaki, Yuko; Suto, Mitsutoshi; Nemoto, Noriko; Kamiya, Kentaro; Itoman, Moritoshi

    2012-03-01

    Frozen bone-patellar tendon bone allografts are useful in anterior cruciate ligament reconstruction as the freezing procedure kills tissue cells, thereby reducing immunogenicity of the grafts. However, a small portion of cells in human femoral heads treated by standard bone-bank freezing procedures survive, thus limiting the effectiveness of allografts. Here, we characterized the survival rates and mechanisms of cells isolated from rat bones and tendons that were subjected to freeze-thaw treatments, and evaluated the influence of these treatments on the mechanical properties of tendons. After a single freeze-thaw cycle, most cells isolated from frozen bone appeared morphologically as osteocytes and expressed both osteoblast- and osteocyte-related genes. Transmission electron microscopic observation of frozen cells using freeze-substitution revealed that a small number of osteocytes maintained large nuclei with intact double membranes, indicating that these osteocytes in bone matrix were resistant to ice crystal formation. We found that tendon cells were completely killed by a single freeze-thaw cycle, whereas bone cells exhibited a relatively high survival rate, although survival was significantly reduced after three freeze-thaw cycles. In patella tendons, the ultimate stress, Young's modulus, and strain at failure showed no significant differences between untreated tendons and those subjected to five freeze-thaw cycles. In conclusion, we identified that cells surviving after freeze-thaw treatment of rat bones were predominantly osteocytes. We propose that repeated freeze-thaw cycles could be applied for processing bone-tendon constructs prior to grafting as the treatment did not affect the mechanical property of tendons and drastically reduced surviving osteocytes, thereby potentially decreasing allograft immunogenecity.

  14. Titania and titania-silica coatings for titanium: comparison of ectopic bone formation within cell-seeded scaffolds.

    PubMed

    Meretoja, Ville V; Tirri, Teemu; Aäritalo, Virpi; Walboomers, X Frank; Jansen, John A; Närhi, Timo O

    2007-04-01

    The aim of this study was to compare titania (TiO(2))-coated, titania-silica (TiSi)-coated, and uncoated (cpTi) titanium fiber meshes as scaffolds for bone engineering. The scaffolds were loaded with bone marrow stromal cells and implanted subcutaneously in rats. Ectopic bone formation after 1, 4, and 12 weeks of implantation was evaluated using histology and histomorphometry. After 1 week of implantation, multiple patches of unorganized mineralizing tissue were seen in all implants. The amount of this bone-like tissue clearly increased from 1 to 4 weeks. Bone apposition occurred in direct contact with coated meshes, while a thin layer of unmineralized fibrous tissue was often observed surrounding cpTi mesh fibers. After 12 weeks, the structure of bone, with bone marrow-like tissue, was further matured and mesh fibers were embedded in lamellar bone. No statistical differences in the amount of mineralized bone were observed between scaffold types at any point of time. Only TiSi scaffolds showed further increase in bone area from 4 to 12 weeks (p < 0.01). A notable difference was that the sol-gel coatings resulted in enhanced initial bone contact and distribution of bone tissue, whereas uncoated implants showed bone formation mainly in the center of the scaffolds. In conclusion, TiO(2)-based sol-gel coatings may be used in tissue engineering to gain more uniform distribution of bone throughout titanium fiber mesh scaffolds.

  15. Ectopic bone formation and chondrodysplasia in transgenic mice carrying the rat C3(1)/T{sub AG} fusion gene

    SciTech Connect

    Green, J.E.; Maroulakou, I.G.; Anver, M.

    1994-09-01

    Transgenic mice expressing the SV40 large T-antigen (T{sup AG}) under the regultory control of the hormone-responsive rat C3(1) prostatein promoter develop unusual bone and cartilage lesions, as well as ectopic bone and cartilage formation. Two lines of transgenic animals have been propagated in which the expression of the transgene in chondrocytes results in a mild to moderate generalized disorganization of cartilage growth which appears to affect multiple tissues, including the trachea, ear pinna and articular cartilage. The epiphyseal plates are also affected with normal architecture of the zones of proliferation and maturation, but marked elongation of the zone of hypertrophy. Immunocytochemistry demonstrates that expression of T{sup AG} is limited to the zone of hypertropny in the epiphyseal plates, suggesting that the chondrocytes become hormone-responsive at this particular stage of differentiation. Normal mineralization and trabecular formation in long bone appears to occur. Ectopic bone and cartilage formation occurs in the foot pads of the fore- and hind- feet over the course of several months. This is preceded by proliferation of sweat gland epithelial cells followed by the appearance of nodules of cartilage and bone. The nodules are closely associated with proliferating epithelium but are not contiguous with bony structures normally found in the feet. The roles of BMP`s, growth factors, oncogenes and hormones in the development of these lesions will be presented. These transgenic animals may provide new insights into hormone-responsiveness of chondrocytes, as well as factors involved in the processes of bone and cartilage differentiation and growth. These transgenic animals may serve as a useful model for human heterotopic bone formation.

  16. Effect of calcium phosphate glass on bone formation in calvarial defects of Sprague-Dawley rats.

    PubMed

    Moon, Hyun-Ju; Kim, Kyoung-Nam; Kim, Kwang-Mahn; Choi, Seong-Ho; Kim, Chong-Kwan; Kim, Kee-Deog; LeGeros, Racquel Z; Lee, Yong-Keun

    2006-09-01

    The purpose of this study was to investigate the bone regenerative effect of calcium phosphate glass in vivo. We prepared two different sizes of calcium phosphate glass powder using the system CaO-CaF2-P2O5-MgO-ZnO; the particle size of the powders were 400 microm and 40 microm. 8 mm calvarial critical-sized defects were created in 60 male Sprague-Dawley rats. The animals were divided into 3 groups of 20 animals each. Each defect was filled with a constant weight of 0.5 g calcium phosphate glass powder mixed with saline. As controls, the defect was left empty. The rats were sacrificed 2 or 8 weeks after postsurgery, and the results were evaluated using radiodensitometric and histological studies; they were also examined histomorphometrically. When the bigger powders with 400 microm particle were grafted, the defects were nearly completely filled with new-formed bone in a clean healing condition after 8 week. When smaller powders with 40 microm particle were transplanted, new bone formation was even lower than the control group due to a lot of inflammatory cell infiltration. It was concluded that the prepared calcium phosphate glass enhanced the new bone formation in the calvarial defect of Sprague-Dawley rats and it is expected to be a good potential materials for hard tissue regeneration. The particle size of the calcium phosphate was crucial; 400 microm particles promoted new bone formation, while 40 microm particles inhibited it because of severe inflammation.

  17. Role of WNT16 in the regulation of periosteal bone formation in female mice.

    PubMed

    Wergedal, Jon E; Kesavan, Chandrasekhar; Brommage, Robert; Das, Subhashri; Mohan, Subburaman

    2015-03-01

    In this study, we evaluated the role of WNT16 in regulating bone size, an important determinant of bone strength. Mice with targeted disruption of the Wnt16 gene exhibited a 24% reduction in tibia cross-sectional area at 12 weeks of age compared with that of littermate wild-type (WT) mice. Histomorphometric studies revealed that the periosteal bone formation rate and mineral apposition rate were reduced (P < .05) by 55% and 32%, respectively, in Wnt16 knockout (KO) vs WT mice at 12 weeks of age. In contrast, the periosteal tartrate resistant acid phosphatase-labeled surface was increased by 20% in the KO mice. Because mechanical strain is an important physiological regulator of periosteal bone formation (BF), we determined whether mechanical loading-induced periosteal BF is compromised in Wnt16 KO mice. Application of 4800-μe strain to the right tibia using a 4-point bending loading method for 2 weeks (2-Hz frequency, 36 cycles per day, 6 days/wk) produced a significant increase in cross-sectional area (11% above that of the unloaded left tibia, P < .05, n = 6) in the WT but not in the KO mice (-0.2% change). Histomorphometric analyses revealed increases in the periosteal bone formation rate and mineral apposition rate in the loaded bones of WT but not KO mice. Wnt16 KO mice showed significant (20%-70%) reductions in the expression levels of markers of canonical (β-catenin and Axin2) but not noncanonical (Nfatc1 and Tnnt2) WNT signaling in the periosteum at 5 weeks of age. Our findings suggest that WNT16 acting via canonical WNT signaling regulates mechanical strain-induced periosteal BF and bone size.

  18. The effects of prostaglandin E2 in growing rats - Increased metaphyseal hard tissue and cortico-endosteal bone formation

    NASA Technical Reports Server (NTRS)

    Jee, W. S. S.; Ueno, K.; Deng, Y. P.; Woodbury, D. M.

    1985-01-01

    The role of in vivo prostaglandin E2 (PGE2) in bone formation is investigated. Twenty-five male Sprague-Dawley rats weighing between 223-267 g were injected subcutaneously with 0.3, 1.0, 3.0, and 6.0 mg of PGE2-kg daily for 21 days. The processing of the tibiae for observation is described. Radiographs and histomorphometric analyses are also utilized to study bone formation. Body weight, weights of soft tissues and bones morphometry are evaluated. It is observed that PGE2 depressed longitudinal bone growth, increased growth cartilage thickness, decreased degenerative cartilage cell size and cartilage cell production, and significantly increased proximal tibial metaphyseal hard tissue mass. The data reveal that periosteal bone formation is slowed down at higher doses of PGE2 and endosteal bone formation is slightly depressed less than 10 days post injection; however, here is a late increase (10 days after post injection) in endosteal bone formation and in the formation of trabecular bone in the marrow cavity of the tibial shaft. It is noted that the effects of PGE2 on bone formation are similar to the responses of weaning rats to PGE2.

  19. Differential mechanisms of de-regulated bone formation in rheumatoid arthritis and spondyloarthritis.

    PubMed

    Goldring, Steven R

    2016-12-01

    The inflammatory arthropathies share in common their tendency to produce marked alterations in skeletal remodelling and architecture. This review will focus on RA and the seronegative spondyloarthopathies (SpA), which share common features with respect to their tendency to produce localized bone destruction at sites of articular and peri-articular inflammation. However, there are significant differences in the skeletal pathology in these conditions, which include the unique involvement of the axial skeleton and the presence of inflammation in the extra-articular entheses in SpA. There also are differences in the pattern of bone formation and repair associated with the articular and peri-articular inflammation. This review will highlight the molecular and cellular processes that are involved in the pathogenesis of the skeletal pathology in these two forms of inflammatory arthritis with specific focus on the pathogenic mechanisms underlying the differential patterns of bone formation and repair.

  20. Arteriovenous Fistula Affects Bone Mineral Density Measurements in End-Stage Renal Failure Patients

    PubMed Central

    Torregrosa, José-Vicente; Fuster, David; Peris, Pilar; Vidal-Sicart, Sergi; Solà, Oriol; Domenech, Beatriz; Martín, Gloria; Casellas, Joan; Pons, Francisca

    2009-01-01

    Background and objectives: Hemodialysis needs an arteriovenous fistula (AVF) that may influence the structure and growth of nearby bone and affect bone mass measurement. The study analyzed the effect of AVF in the assessment of forearm bone mineral density (BMD) measured by dual energy x-ray absorptiometry (DXA) and examined its influence on the final diagnosis of osteoporosis. Design, setting, participants, & measurements: Forty patients (52 ± 18 yr) in hemodialysis program (12 ± 8 yr) with permeable AVF in forearm were included. Patients were divided in two groups (over and under 50 yr). BMD of both forearms (three areas), lumbar spine, and femur was measured by DXA. Forearm measurements in each arm were compared. Patients were diagnosed as normal only if all territories were considered nonpathologic and osteoporosis/osteopenia was determined by the lowest score found. Results: Ten patients were excluded and 30 patients were analyzed. BMD in the forearm with AVF was significantly lower than that observed in the contralateral forearm in both groups of patients and in all forearm areas analyzed. When only lumbar spine and femur measurements were considered, 70% of patients were nonpathologic and 30% were osteoporotic. However, inclusion of AVF forearm classified 63% as osteoporotic and a further 27% as osteopenic, leaving only 10% as nonpathologic. Conclusions: Forearm AVF affects BMD measurements by decreasing their values in patients with end-stage renal failure. This may produce an overdiagnosis of osteoporosis, which should be taken into account when evaluating patients of this type. PMID:19713298

  1. Non-invasive monitoring of BMP-2 retention and bone formation in composites for bone tissue engineering using SPECT/CT and scintillation probes.

    PubMed

    Kempen, Diederik H R; Yaszemski, Michael J; Heijink, Andras; Hefferan, Theresa E; Creemers, Laura B; Britson, Jason; Maran, Avudaiappan; Classic, Kelly L; Dhert, Wouter J A; Lu, Lichun

    2009-03-19

    Non-invasive imaging can provide essential information for the optimization of new drug delivery-based bone regeneration strategies to repair damaged or impaired bone tissue. This study investigates the applicability of nuclear medicine and radiological techniques to monitor growth factor retention profiles and subsequent effects on bone formation. Recombinant human bone morphogenetic protein-2 (BMP-2, 6.5 microg/scaffold) was incorporated into a sustained release vehicle consisting of poly(lactic-co-glycolic acid) microspheres embedded in a poly(propylene fumarate) scaffold surrounded by a gelatin hydrogel and implanted subcutaneously and in 5-mm segmental femoral defects in 9 rats for a period of 56 days. To determine the pharmacokinetic profile, BMP-2 was radiolabeled with (125)I and the local retention of (125)I-BMP-2 was measured by single photon emission computed tomography (SPECT), scintillation probes and ex vivo scintillation analysis. Bone formation was monitored by micro-computed tomography (microCT). The scaffolds released BMP-2 in a sustained fashion over the 56-day implantation period. A good correlation between the SPECT and scintillation probe measurements was found and there were no significant differences between the non-invasive and ex-vivo counting method after 8 weeks of follow up. SPECT analysis of the total body and thyroid counts showed a limited accumulation of (125)I within the body. Ectopic bone formation was induced in the scaffolds and the femur defects healed completely. In vivo microCT imaging detected the first signs of bone formation at days 14 and 28 for the orthotopic and ectopic implants, respectively, and provided a detailed profile of the bone formation rate. Overall, this study clearly demonstrates the benefit of applying non-invasive techniques in drug delivery-based bone regeneration strategies by providing detailed and reliable profiles of the growth factor retention and bone formation at different implantation sites in a

  2. Non-invasive monitoring of BMP-2 retention and bone formation in composites for bone tissue engineering using SPECT/CT and scintillation probes

    PubMed Central

    Kempen, Diederik H.R.; Yaszemski, Michael J.; Heijink, Andras; Hefferan, Theresa E.; Creemers, Laura B.; Britson, Jason; Maran, Avudaiappan; Classic, Kelly L.; Dhert, Wouter J.A.; Lu, Lichun

    2014-01-01

    Non-invasive imaging can provide essential information for the optimization of new drug delivery-based bone regeneration strategies to repair damaged or impaired bone tissue. This study investigates the applicability of nuclear medicine and radiological techniques to monitor growth factor retention profiles and subsequent effects on bone formation. Recombinant human bone morphogenetic protein-2 (BMP-2, 6.5 μg/scaffold) was incorporated into a sustained release vehicle consisting of poly(lactic-co-glycolic acid) microspheres embedded in a poly(propylene fumarate) scaffold surrounded by a gelatin hydrogel and implanted subcutaneously and in 5-mm segmental femoral defects in 9 rats for a period of 56 days. To determine the pharmacokinetic profile, BMP-2 was radiolabeled with 125I and the local retention of 125I-BMP-2 was measured by single photon emission computed tomography (SPECT), scintillation probes and ex vivo scintillation analysis. Bone formation was monitored by micro-computed tomography (μCT). The scaffolds released BMP-2 in a sustained fashion over the 56-day implantation period. A good correlation between the SPECT and scintillation probe measurements was found and there were no significant differences between the non-invasive and ex-vivo counting method after 8 weeks of follow up. SPECT analysis of the total body and thyroid counts showed a limited accumulation of 125I within the body. Ectopic bone formation was induced in the scaffolds and the femur defects healed completely. In vivo μCT imaging detected the first signs of bone formation at days 14 and 28 for the orthotopic and ectopic implants, respectively, and provided a detailed profile of the bone formation rate. Overall, this study clearly demonstrates the benefit of applying non-invasive techniques in drug delivery-based bone regeneration strategies by providing detailed and reliable profiles of the growth factor retention and bone formation at different implantation sites in a limited number

  3. The primary function of gp130 signaling in osteoblasts is to maintain bone formation and strength, rather than promote osteoclast formation.

    PubMed

    Johnson, Rachelle W; Brennan, Holly J; Vrahnas, Christina; Poulton, Ingrid J; McGregor, Narelle E; Standal, Therese; Walker, Emma C; Koh, Thuan-Tzen; Nguyen, Huynh; Walsh, Nicole C; Forwood, Mark R; Martin, T John; Sims, Natalie A

    2014-06-01

    Interleukin-6 (IL-6) family cytokines act via gp130 in the osteoblast lineage to stimulate the formation of osteoclasts (bone resorbing cells) and the activity of osteoblasts (bone forming cells), and to inhibit expression of the osteocyte protein, sclerostin. We report here that a profound reduction in trabecular bone mass occurs both when gp130 is deleted in the entire osteoblast lineage (Osx1Cre gp130 f/f) and when this deletion is restricted to osteocytes (DMP1Cre gp130 f/f). This was caused not by an alteration in osteoclastogenesis, but by a low level of bone formation specific to the trabecular compartment. In contrast, cortical diameter increased to maintain ultimate bone strength, despite a reduction in collagen type 1 production. We conclude that osteocytic gp130 signaling is required for normal trabecular bone mass and proper cortical bone composition.

  4. Influence of fluoride in poly(d,l-lactide)/apatite composites on bone formation.

    PubMed

    Luo, X; Barbieri, D; Passanisi, G; Yuan, H; de Bruijn, J D

    2015-05-01

    The influence of fluoride in poly(d,l-lactide)/apatite composites on ectopic bone formation was evaluated in sheep. Nano-apatite powders with different replacement levels of OH groups by fluoride (F) (0% (F0), 50% (F50), 100% (F100), and excessive (F200)) were co-extruded with poly (d,l-lactide) at a weight ratio of 1:1. Fluoride release from the composites (CF0, CF50, CF100, and CF200) was evaluated in vitro and bone formation was assessed after intramuscular implantation in sheep. After 24 weeks in simulated physiological solution, CF0 and CF50 showed negligible fluoride release, whereas it was considerable from the CF100 and CF200 composites. Histology showed that the incidence of de novo bone formation decreased in implants with increasing fluoride content indicating a negative influence of fluoride on ectopic bone formation. Furthermore, a significant decrease in resorption of the high fluoride-content composites and a reduction in the number of multinucleated giant cells were seen. These results show that instead of promoting, the presence of fluoride in poly(d,l-lactide)/apatite composites seemed to suppresses their resorption and osteoinductive potential in non-osseous sites.

  5. Effect of caffeic acid phenethyl ester on bone formation in the expanded inter-premaxillary suture

    PubMed Central

    Kazancioglu, Hakki Oguz; Aksakalli, Sertac; Ezirganli, Seref; Birlik, Muhammet; Esrefoglu, Mukaddes; Acar, Ahmet Hüseyin

    2015-01-01

    Background Narrow maxilla is a common problem in orthodontics and dentofacial orthopedics. To solve this problem, a procedure called rapid maxillary expansion (RME) has been used. However, relapse tendency is a major problem of RME. Although relapse tendency is not clearly understood, various treatment procedures and new applications have been investigated. The present study aimed to investigate the possible effectiveness of caffeic acid phenethyl ester (CAPE) on new bone formation in rat midpalatal suture after RME. Materials and methods Twenty male Sprague Dawley rats were used in this study. The animals were randomly divided into two groups as control and CAPE group. In the CAPE group, CAPE was administered systemically via intraperitoneal injection. RME procedure was performed on all animals. For this purpose, the springs were placed on the maxillary incisors of rats and activated for 5 days. After then, the springs were removed and replaced with short lengths of rectangular retaining wire for consolidation period of 15 days. At the end of the study, histomorphometric analysis was carried out to assess new bone formation. Results New bone formation was significantly greater in the CAPE group than the control group (P<0.05). CAPE enhances new bone formation in midpalatal suture after RME. Conclusion These results show that CAPE may decrease the time needed for retention. PMID:26730181

  6. Interferon-γ plays a role in bone formation in vivo and rescues osteoporosis in ovariectomized mice.

    PubMed

    Duque, Gustavo; Huang, Dao Chao; Dion, Natalie; Macoritto, Michael; Rivas, Daniel; Li, Wei; Yang, Xian Fang; Li, Jiarong; Lian, Jing; Marino, Faleh Tamim; Barralet, Jake; Lascau, Viorica; Deschênes, Claire; Ste-Marie, Louis-Georges; Kremer, Richard

    2011-07-01

    Interferon γ (IFN-γ) is a cytokine produced locally in the bone microenvironment by cells of immune origin as well as mesenchymal stem cells. However, its role in normal bone remodeling is still poorly understood. In this study we first examined the consequences of IFN-γ ablation in vivo in C57BL/6 mice expressing the IFN-γ receptor knockout phenotype (IFNγR1(-/-)). Compared with their wild-type littermates (IFNγR1(+/+)), IFNγR1(-/-) mice exhibit a reduction in bone volume associated with significant changes in cortical and trabecular structural parameters characteristic of an osteoporotic phenotype. Bone histomorphometry of IFNγR1(-/-) mice showed a low-bone-turnover pattern with a decrease in bone formation, a significant reduction in osteoblast and osteoclast numbers, and a reduction in circulating levels of bone-formation and bone-resorption markers. Furthermore, administration of IFN-γ (2000 and 10,000 units) to wild-type C57BL/6 sham-operated (SHAM) and ovariectomized (OVX) female mice significantly improved bone mass and microarchitecture, mechanical properties of bone, and the ratio between bone formation and bone resorption in SHAM mice and rescued osteoporosis in OVX mice. These data therefore support an important physiologic role for IFN-γ signaling as a potential new anabolic therapeutic target for osteoporosis.

  7. New bone formation in a bone defect associated to dental implant using absorbable or non-absorbable membrane in a dog model

    PubMed Central

    Lopez, Maria de Almeida; Olate, Sergio; Lanata-Flores, Antonio; Pozzer, Leandro; Cavalieri-Pereira, Lucas; Cantín, Mario; Vásquez, Bélgica; de Albergaria-Barbosa, José

    2013-01-01

    The aim of this research was to determine the bone formation capacity in fenestration defects associated with dental implants using absorbable and non-absorbable membranes. Six dogs were used in the study. In both tibias of each animal 3 implants were installed, and around these 5 mm circular defects were created. The defects were covered with absorbable membranes (experimental group 1), non-absorbable membranes (experimental group 2), and the third defect was not covered (control group). At 3 and 8 weeks post-surgery, the animals were euthanized and the membranes with the bone tissue around the implants were processed for histological analysis. The statistical analysis was conducted with Tukey’s test, considering statistical significance when p<0.1. Adequate bone repair was observed in the membrane-covered defects. At 3 weeks, organization of the tissue, bone formation from the periphery of the defect and the absence of inflammatory infiltrate were observed in both experimental groups, but the defect covered with absorbable membrane presented statistically greater bone formation. At 8 weeks, both membrane-covered defects showed adequate bone formation without significant differences, although they did in fact present differences with the control defect in both periods (p>0.1). In the defects without membrane, continuous connective tissue invasions and bone repair deficiency were observed. There were no significant differences in the characteristics and volume of the neoformed bone in the defects around the implants covered by the different membranes, whereas the control defects produced significantly less bone. The use of biological membranes contributes to bone formation in three-wall defects. PMID:24228090

  8. Pyrroloquinoline quinone prevents testosterone deficiency-induced osteoporosis by stimulating osteoblastic bone formation and inhibiting osteoclastic bone resorption

    PubMed Central

    Wu, Xuan; Li, Jie; Zhang, Hengwei; Wang, Hui; Yin, Guoyong; Miao, Dengshun

    2017-01-01

    Accumulating evidences suggest that oxidative stress caused and deteriorated the aging related osteoporosis and pyrroloquinoline quinone (PQQ) is a powerful antioxidant. However, it is unclear whether PQQ can prevent testosterone deficiency-induced osteoporosis. In this study, the orchidectomized (ORX) mice were supplemented in diet with/without PQQ for 48 weeks, and compared with each other and with sham mice. Results showed that bone mineral density, trabecular bone volume, collagen deposition and osteoblast number were decreased significantly in ORX mice compared with shame mice, whereas PQQ supplementation largely prevented these alterations. In contrast, osteoclast surface and ratio of RANKL and OPG mRNA relative expression levels were increased significantly in ORX mice compared with shame mice, but were decreased significantly by PQQ supplementation. Furthermore, we found that CFU-f and ALP positive CFU-f forming efficiency and the proliferation of mesenchymal stem cells were reduced significantly in ORX mice compared with shame mice, but were increased significantly by PQQ supplementation. Reactive oxygen species (ROS) levels in thymus were increased, antioxidant enzymes SOD-1, SOD-2, Prdx I and Prdx IV protein expression levels in bony tissue were down-regulated, whereas the protein expression levels of DNA damage response related molecules including γ-H2AX, p53, Chk2 and NFκB-p65 in bony tissue were up-regulated significantly in ORX mice compared with shame mice, whereas PQQ supplementation largely rescued these alterations observed in ORX mice. Our results indicate that PQQ supplementation can prevent testosterone deficiency-induced osteoporosis by inhibiting oxidative stress and DNA damage, stimulating osteoblastic bone formation and inhibiting osteoclastic bone resorption. PMID:28386349

  9. Erythropoietin augments bone formation in a rabbit posterolateral spinal fusion model.

    PubMed

    Rölfing, Jan Hendrik Duedal; Bendtsen, Michael; Jensen, Jonas; Stiehler, Maik; Foldager, Casper Bindzus; Hellfritzsch, Michel Bach; Bünger, Cody

    2012-07-01

    We tested the hypothesis that erythropoietin (EPO) enhances bone formation after posterolateral spinal fusion (PLF) in a rabbit model. Thirty-four adult rabbits underwent posterolateral intertransverse arthrodesis at the L5-L6 level using 2.0 g autograft per side. The animals were randomly divided into two groups receiving subcutaneous daily injections of either EPO or saline for 20 days. Treatment commenced 2 days preoperatively. Hemoglobin was monitored at baseline and 2, 4, and 6 weeks after fusion surgery. After euthanasia 6 weeks postoperatively, manual palpation, radiographic, and histomorphometric examinations were performed. Bone volume of the fusion mass was estimated by CT after 6 weeks. EPO increased bone fusion volume to 3.85 ccm (3.66-4.05) compared with 3.26 ccm (2.97-3.55) in the control group (p<0.01). EPO treatment improved vascularization of the fusion mass and increased hemoglobin levels (p<0.01). Fusion rate tended to be higher in the EPO group based on manual palpation, CT, and radiographic examinations. For the first time EPO has shown to augment bone formation after autograft PLF in a rabbit model. Increased vascularization provides a partial explanation for the efficacy of EPO as a bone autograft enhancer.

  10. Model system for studies on bone matrix formation by osteogenic cells in microgravity

    NASA Astrophysics Data System (ADS)

    Quinton, Todd M.; Fattaey, Heideh K.; Motaffaf, Farzaneh; Johnson, Terry C.

    1998-01-01

    A considerable amount of attention has been focused on the physiological factors that are responsible for the reduction of bone mineralization and mass during prolonged periods in the microgravity environment. Although bone mineralization can be reduced by one percent per month as shown to result from shuttle flights and Mir habitation, the reasons for this phenomenon remain unclear. Changes in specific markers of bone cells upon differentiation indicate that the induction of bone matrix formation is dependent upon these cells reaching confluency. In our laboratory, we have isolated a reversible inhibitor of cellular growth (CeReS-18) that could be important in cell contact inhibition and thus may mimic the signals involved in growth confluency. Preliminary experiments with osteogenic cells have revealed the potential capability of CeReS-18 to inhibit these cells in a reversible manner. We are developing a series of studies, designed at the cellular level, to quantitatively measure the production of bone matrix by osteogenic cells propagated in culture. The use of CeReS-18 would facilitate the study of several factors being assessed regarding matrix formation including the rate of cell population density, hormone induction events, calcium availability, and cell cycle arest. The studies are being conducted in a manner that will allow comparable measurements in the microgravity environment with flight hardware designed and deployed by BioServe Space Technologies.

  11. The role of intracellular calcium phosphate in osteoblast-mediated bone apatite formation

    PubMed Central

    Boonrungsiman, Suwimon; Gentleman, Eileen; Carzaniga, Raffaella; Evans, Nicholas D.; McComb, David W.; Porter, Alexandra E.; Stevens, Molly M.

    2012-01-01

    Mineralization is a ubiquitous process in the animal kingdom and is fundamental to human development and health. Dysfunctional or aberrant mineralization leads to a variety of medical problems, and so an understanding of these processes is essential to their mitigation. Osteoblasts create the nano-composite structure of bone by secreting a collagenous extracellular matrix (ECM) on which apatite crystals subsequently form. However, despite their requisite function in building bone and decades of observations describing intracellular calcium phosphate, the precise role osteoblasts play in mediating bone apatite formation remains largely unknown. To better understand the relationship between intracellular and extracellular mineralization, we combined a sample-preparation method that simultaneously preserved mineral, ions, and ECM with nano-analytical electron microscopy techniques to examine osteoblasts in an in vitro model of bone formation. We identified calcium phosphate both within osteoblast mitochondrial granules and intracellular vesicles that transported material to the ECM. Moreover, we observed calcium-containing vesicles conjoining mitochondria, which also contained calcium, suggesting a storage and transport mechanism. Our observations further highlight the important relationship between intracellular calcium phosphate in osteoblasts and their role in mineralizing the ECM. These observations may have important implications in deciphering both how normal bone forms and in understanding pathological mineralization. PMID:22879397

  12. Osteochondrosis Can Lead to Formation of Pseudocysts and True Cysts in the Subchondral Bone of Horses.

    PubMed

    Olstad, K; Østevik, L; Carlson, C S; Ekman, S

    2015-09-01

    Osteochondrosis arises as a result of focal failure of the blood supply to growth cartilage. The current aim was to examine the pathogenesis of pseudocysts and true cysts in subchondral bone following failure of the blood supply to the articular-epiphyseal cartilage complex in horses. Cases were recruited based on identification of lesions (n = 17) that were considered likely to progress to or to represent pseudocysts or true cysts in epiphyseal bone in histological sections and included 10 horses ranging in age from 48 days to 5 years old. Cases comprised 3 warmbloods, 3 Standardbreds, 1 Quarter horse and 1 Arabian with spontaneous lesions and 2 Fjord ponies with experimentally induced lesions. Seven lesions consisted of areas of ischemic chondronecrosis and were compatible with pseudocysts. Two lesions were located at intermediate depth in epiphyseal growth cartilage, 2 lesions were located in the ossification front, 2 lesions were located in epiphyseal bone and 1 lesion was located in the metaphyseal growth plate (physis). Ten lesions contained dilated blood vessels and were compatible with true cysts. In 2 lesions the dilated blood vessels were located within the lumina of failed cartilage canals. In the 8 remaining lesions areas of ischemic chondronecrosis were associated with granulation tissue in the subjacent bone and dilated vessels were located within this granulation tissue. Failure of the blood supply and ischemic chondronecrosis can lead to formation of pseudocysts or dilatation of blood vessels and formation of true cysts in the epiphyseal bone of horses.

  13. Hypertrophic chondrocytes can become osteoblasts and osteocytes in endochondral bone formation

    PubMed Central

    Yang, Liu; Tsang, Kwok Yeung; Tang, Hoi Ching; Chan, Danny; Cheah, Kathryn S. E.

    2014-01-01

    According to current dogma, chondrocytes and osteoblasts are considered independent lineages derived from a common osteochondroprogenitor. In endochondral bone formation, chondrocytes undergo a series of differentiation steps to form the growth plate, and it generally is accepted that death is the ultimate fate of terminally differentiated hypertrophic chondrocytes (HCs). Osteoblasts, accompanying vascular invasion, lay down endochondral bone to replace cartilage. However, whether an HC can become an osteoblast and contribute to the full osteogenic lineage has been the subject of a century-long debate. Here we use a cell-specific tamoxifen-inducible genetic recombination approach to track the fate of murine HCs and show that they can survive the cartilage-to-bone transition and become osteogenic cells in fetal and postnatal endochondral bones and persist into adulthood. This discovery of a chondrocyte-to-osteoblast lineage continuum revises concepts of the ontogeny of osteoblasts, with implications for the control of bone homeostasis and the interpretation of the underlying pathological bases of bone disorders. PMID:25092332

  14. Tenascin-W inhibits proliferation and differentiation of preosteoblasts during endochondral bone formation

    SciTech Connect

    Kimura, Hiroaki; Akiyama, Haruhiko . E-mail: hakiyama@kuhp.kyoto-u.ac.jp; Nakamura, Takashi; Crombrugghe, Benoit de

    2007-05-18

    We identified a cDNA encoding mouse Tenascin-W (TN-W) upregulated by bone morphogenetic protein (Bmp)2 in ATDC5 osteo-chondroprogenitors. In adult mice, TN-W was markedly expressed in bone. In mouse embryos, during endochondral bone formation TN-W was localized in perichondrium/periosteum, but not in trabecular and cortical bones. During bone fracture repair, cells in the newly formed perichondrium/periosteum surrounding the cartilaginous callus expressed TN-W. Furthermore, TN-W was detectable in perichondrium/periosteum of Runx2-null and Osterix-null embryos, indicating that TN-W is expressed in preosteoblasts. In CFU-F and -O cells, TN-W had no effect on initiation of osteogenesis of bone marrow cells, and in MC3T3-E1 osteoblastic cells TN-W inhibited cell proliferation and Col1a1 expression. In addition, TN-W suppressed canonical Wnt signaling which stimulates osteoblastic differentiation. Our results indicate that TN-W is a novel marker of preosteoblasts in early stage of osteogenesis, and that TN-W inhibits cell proliferation and differentiation of preosteoblasts mediated by canonical Wnt signaling.

  15. mTORC2 Signaling Promotes Skeletal Growth and Bone Formation in Mice

    PubMed Central

    Chen, Jianquan; Holguin, Nilsson; Shi, Yu; Silva, Matthew J.; Long, Fanxin

    2015-01-01

    Mammalian target of rapamycin (mTOR) is an evolutionarily conserved serine/threonine kinase controlling many physiological processes in mammals. mTOR functions in two distinct protein complexes, namely mTORC1 and mTORC2. Compared to mTORC1, the specific roles of mTORC2 are less well understood. To investigate the potential contribution of mTORC2 to skeletal development and homeostasis, we have genetically deleted Rictor, an essential component of mTORC2, in the limb skeletogenic mesenchyme of the mouse embryo. Loss of Rictor leads to shorter and narrower skeletal elements in both embryos and postnatal mice. In the embryo, Rictor deletion reduces the width but not the length of the initial cartilage anlage. Subsequently, the embryonic skeletal elements are shortened due to a delay in chondrocyte hypertrophy, with no change in proliferation, apoptosis, cell size, or matrix production. Postnatally, Rictor-deficient mice exhibit impaired bone formation, resulting in thinner cortical bone, but the trabecular bone mass is relatively normal thanks to a concurrent decrease in bone resorption. Moreover, Rictor-deficient bones exhibit a lesser anabolic response to mechanical loading. Thus, mTORC2 signaling is necessary for optimal skeletal growth and bone anabolism. PMID:25196701

  16. Open source software for semi-automated histomorphometry of bone resorption and formation parameters.

    PubMed

    van 't Hof, Rob J; Rose, Lorraine; Bassonga, Euphemie; Daroszewska, Anna

    2017-03-31

    Micro-CT analysis has become the standard method for assessing bone volume and architecture in small animals. However, micro-CT does not allow the assessment of bone turnover parameters such as bone formation rate and osteoclast (OC) number and surface. For these crucial variables histomorphometric analysis is still an essential technique. Histomorphometry however, is time consuming and, especially in mouse bones, OCs can be difficult to detect. The main purpose of this study was to develop and validate a relatively easy and rapid method to measure static and dynamic bone histomorphometry parameters. Here we present the adaptation of established staining protocols and three novel open source image analysis packages: TrapHisto, OsteoidHisto and CalceinHisto that allow rapid, semi-automated analysis of histomorphometric bone resorption, osteoid, and calcein double labelling parameters respectively. These three programs are based on ImageJ, but use a relatively simple user interface that hides the underlying complexity of the image analysis.

  17. Inhibition of apoptosis signal-regulating kinase 1 enhances endochondral bone formation by increasing chondrocyte survival

    PubMed Central

    Eaton, G J; Zhang, Q-S; Diallo, C; Matsuzawa, A; Ichijo, H; Steinbeck, M J; Freeman, T A

    2014-01-01

    Endochondral ossification is the result of chondrocyte differentiation, hypertrophy, death and replacement by bone. The careful timing and progression of this process is important for normal skeletal bone growth and development, as well as fracture repair. Apoptosis Signal-Regulating Kinase 1 (ASK1) is a mitogen-activated protein kinase (MAPK), which is activated by reactive oxygen species and other cellular stress events. Activation of ASK1 initiates a signaling cascade known to regulate diverse cellular events including cytokine and growth factor signaling, cell cycle regulation, cellular differentiation, hypertrophy, survival and apoptosis. ASK1 is highly expressed in hypertrophic chondrocytes, but the role of ASK1 in skeletal tissues has not been investigated. Herein, we report that ASK1 knockout (KO) mice display alterations in normal growth plate morphology, which include a shorter proliferative zone and a lengthened hypertrophic zone. These changes in growth plate dynamics result in accelerated long bone mineralization and an increased formation of trabecular bone, which can be attributed to an increased resistance of terminally differentiated chondrocytes to undergo cell death. Interestingly, under normal cell culture conditions, mouse embryonic fibroblasts (MEFs) derived from ASK1 KO mice show no differences in either MAPK signaling or osteogenic or chondrogenic differentiation when compared with wild-type (WT) MEFs. However, when cultured with stress activators, H2O2 or staurosporine, the KO cells show enhanced survival, an associated decrease in the activation of proteins involved in death signaling pathways and a reduction in markers of terminal differentiation. Furthermore, in both WT mice treated with the ASK1 inhibitor, NQDI-1, and ASK1 KO mice endochondral bone formation was increased in an ectopic ossification model. These findings highlight a previously unrealized role for ASK1 in regulating endochondral bone formation. Inhibition of ASK1 has

  18. Pyk2 Regulates Megakaryocyte-Induced Increases in Osteoblast Number and Bone Formation

    PubMed Central

    Cheng, Ying-Hua; Hooker, R. Adam; Nguyen, Khanh; Gerard-O’Riley, Rita; Waning, David L.; Chitteti, Brahmananda R.; Meijome, Tomas E.; Chua, Hui Lin; Plett, Artur P.; Orschell, Christie M.; Srour, Edward F.; Mayo, Lindsey D.; Pavalko, Fredrick M.; Bruzzaniti, Angela; Kacena, Melissa A.

    2013-01-01

    Pre-clinical and clinical evidence from megakaryocyte (MK) related diseases suggest that MKs play a significant role in maintaining bone homeostasis. Findings from our laboratories reveal that MKs significantly increase osteoblast (OB) number through direct MK-OB contact and the activation of integrins. We therefore examined the role of Pyk2, a tyrosine kinase known to be regulated downstream of integrins, in the MK-mediated enhancement of OBs. When OBs were co-cultured with MKs, total Pyk2 levels in OBs were significantly enhanced primarily due to increased Pyk2 gene transcription. Additionally, p53 and Mdm2 were both decreased in OBs upon MK stimulation, which would be permissive of cell cycle entry. We then demonstrated that OB number was markedly reduced when Pyk2−/− OBs, as opposed to wild-type (WT) OBs, were co-cultured with MKs. We also determined that MKs inhibit OB differentiation in the presence and absence of Pyk2 expression. Finally, given that MK replete spleen cells from GATA-1 deficient mice can robustly stimulate OB proliferation and bone formation in WT mice, we adoptively transferred spleen cells from these mice into Pyk2−/− recipient mice. Importantly, GATA-1 deficient spleen cells failed to stimulate an increase in bone formation in Pyk2−/− mice, suggesting in vivo the important role of Pyk2 in the MK-induced increase in bone volume. Further understanding of the signaling pathways involved in the MK-mediated enhancement of OB number and bone formation will facilitate the development of novel anabolic therapies to treat bone loss diseases. PMID:23362087

  19. Evidence for efficacy of drugs affecting bone metabolism in preventing hip fracture.

    PubMed Central

    Kanis, J. A.; Johnell, O.; Gullberg, B.; Allander, E.; Dilşen, G.; Gennari, C.; Lopes Vaz, A. A.; Lyritis, G. P.; Mazzuoli, G.; Miravet, L.

    1992-01-01

    OBJECTIVE--To examine the effects of taking drugs affecting bone metabolism on the risk of hip fracture in women aged over 50 years. DESIGN--Retrospective, population based, case-control study by questionnaire. SETTING--14 centres in six countries in southern Europe. SUBJECTS--2086 women with hip fracture and 3532 control women matched for age. MAIN OUTCOME MEASURES--Number of drugs affecting bone metabolism taken and length taken for. RESULTS--Women taking drugs affecting bone metabolism had a significantly decreased risk of hip fracture. After adjustment for differences in other risk factors, the relative risk of hip fractures was 0.55 (95% confidence interval 0.31 to 0.85) in women taking oestrogens, 0.75 (0.60 to 0.94) in those taking calcium, and 0.69 (0.51 to 0.92) in those taking calcitonin. The fall in risk was not significant for anabolic steroids (0.6 (0.29 to 1.22)). Neither vitamin D nor fluorides were associated with a significant decrease in the risk of hip fracture. The effect on hip fracture risk increased significantly with increasing duration of exposure (risk ratio 0.8 (0.61 to 1.05) for less than median exposure v 0.66 (0.5 to 0.88) for greater than median exposure). Drugs were equally effective in older and younger women, with the exception of oestrogen. CONCLUSIONS--Oestrogen, calcium, and calcitonins significantly decrease the risk of hip fracture. Short term intervention late in the natural course of osteoporosis may have significant effects on the incidence of hip fracture. PMID:1463947

  20. Transgenic Expression of Osteoactivin/gpnmb Enhances Bone Formation in Vivo and Osteoprogenitor Differentiation ex Vivo

    PubMed Central

    Frara, Nagat; Abdelmagid, Samir M.; Sondag, Gregory R.; Moussa, Fouad M.; Yingling, Vanessa R.; Owen, Thomas A.; Popoff, Steven N.; Barbe, Mary F.; Safadi, Fayez F.

    2015-01-01

    Initial identification of osteoactivin (OA)/glycoprotein non-melanoma clone B (gpnmb) was demonstrated in an osteopetrotic rat model, where OA expression was increased 3-fold in mutant bones, compared to normal. OA mRNA and protein expression increase during active bone regeneration post-fracture, and primary rat osteoblasts show increased OA expression during differentiation in vitro. To further examine OA/gpnmb as an osteoinductive agent, we characterized the skeletal phenotype of transgenic mouse overexpressing OA/gpnmb under the CMV-promoter (OA-Tg). Western blot analysis showed increased OA/gpnmb in OA-Tg osteoblasts, compared to wild-type (WT). In OA-Tg mouse femurs versus WT littermates, micro-CT analysis showed increased trabecular bone volume and thickness, and cortical bone thickness; histomorphometry showed increased osteoblast numbers, bone formation and mineral apposition rates in OA-Tg mice; and biomechanical testing showed higher peak moment and stiffness. Given that OA/gpnmb is also over-expressed in osteoclasts in OA-Tg mice, we evaluated bone resorption by ELISA and histomorphometry, and observed decreased serum CTX-1 and RANK-L, and decreased osteoclast numbers in OA-Tg, compared to WT mice, indicating decreased bone remodeling in OA-Tg mice. The proliferation rate of OA-Tg osteoblasts in vitro was higher, compared to WT, as was alkaline phosphatase staining and activity, the latter indicating enhanced differentiation of OA-Tg osteoprogenitors. Quantitative RT-PCR analysis showed increased TGF-β1 and TGF-β receptors I and II expression in OA-Tg osteoblasts, compared to WT. Together, these data suggest that OA overexpression has an osteoinductive effect on bone mass in vivo and stimulates osteoprogenitor differentiation ex vivo. PMID:25899717

  1. Local delivery of FTY720 accelerates cranial allograft incorporation and bone formation

    PubMed Central

    Huang, Cynthia; Das, Anusuya; Barker, Daniel; Tholpady, Sunil; Wang, Tiffany; Cui, Quanjun; Ogle, Roy

    2012-01-01

    Endogenous stem cell recruitment to the site of skeletal injury is key to enhanced osseous remodeling and neovascularization. To this end, this study utilized a novel bone allograft coating of poly(lactic-co-glycolic acid) (PLAGA) to sustain the release of FTY720, a selective agonist for sphingosine 1-phosphate (S1P) receptors, from calvarial allografts. Uncoated allografts, vehicle-coated, low dose FTY720 in PLAGA (1:200 w:w) and high dose FTY720 in PLAGA (1:40) were implanted into critical size calvarial bone defects. The ability of local FTY720 delivery to promote angiogenesis, maximize osteoinductivity and improve allograft incorporation by recruitment of bone progenitor cells from surrounding soft tissues and microcirculation was evaluated. FTY720 bioactivity after encapsulation and release was confirmed with sphingosine kinase 2 assays. HPLC-MS quantified about 50% loaded FTY720 release of the total encapsulated drug (4.5 µg) after 5 days. Following 2 weeks of defect healing, FTY720 delivery led to statistically significant increases in bone volumes compared to controls, with total bone volume increases for uncoated, coated, low FTY720 and high FTY720 of 5.98, 3.38, 7.2 and 8.9 mm3, respectively. The rate and extent of enhanced bone growth persisted through week 4 but, by week 8, increases in bone formation in FTY720 groups were no longer statistically significant. However, micro-computed tomography (microCT) of contrast enhanced vascular ingrowth (MICROFIL®) and histological analysis showed enhanced integration as well as directed bone growth in both high and low dose FTY720 groups compared to controls. PMID:21863314

  2. Micro-CT analysis with multiple thresholds allows detection of bone formation and resorption during ultrasound-treated fracture healing.

    PubMed

    Freeman, Theresa A; Patel, Payal; Parvizi, Javad; Antoci, Valentin; Shapiro, Irving M

    2009-05-01

    Multiple threshold algorithms applied to microcomputed tomography analysis were used to probe the effects of low-intensity pulsed ultrasound on fracture healing. Rat femurs were fractured in accordance with IACUC guidelines. Ultrasound treatment was administered daily to one femur; the contralateral bone was treated with a sham transducer. Each week for 3 weeks healing fractures were harvested and scanned by micro-CT. Remodeling activity was confirmed by evaluation of TRAP activity. Using thresholds of 331-700 and 225-330, area of cortical bone, and new bone formation, respectively, were identified, and by inference, regions of bone resorption. The increased sensitivity of this multithresholding procedure revealed that ultrasound treatment significantly increased the rate of fracture healing in vivo by activating both new bone formation and by increasing the removal of cortical bone in a time- and site-specific manner. At week 1, compared to the proximal side, there was a significant increase in new bone formation distal to the fracture site. Removal of the existing cortical bone followed the same pattern at week 2. Results of the study indicate that at sites of bone turnover, this multithresholding analytical technique can be used to provide quantitative information on bone formation, as well as resorption.

  3. Synergistic Effects of Vascular Endothelial Growth Factor on Bone Morphogenetic Proteins Induced Bone Formation In Vivo: Influencing Factors and Future Research Directions

    PubMed Central

    Li, Bo; Wang, Hai; Qiu, Guixing; Su, Xinlin

    2016-01-01

    Vascular endothelial growth factor (VEGF) and bone morphogenetic proteins (BMPs), as key mediators in angiogenesis and osteogenesis, are used in a combined delivery manner as a novel strategy in bone tissue engineering. VEGF has the potential to enhance BMPs induced bone formation. Both gene delivery and material-based delivery systems were incorporated in previous studies to investigate the synergistic effects of VEGF and BMPs. However, their results were controversial due to variation of methods incorporated in different studies. Factors influencing the synergistic effects of VEGF on BMPs induced bone formation were identified and analyzed in this review to reduce confusion on this issue. The potential mechanisms and directions of future studies were also proposed here. Further investigating mechanisms of the synergistic effects and optimizing these influencing factors will help to generate more effective bone regeneration. PMID:28070506

  4. Bone resorption is affected by follicular phase length in female rotating shift workers.

    PubMed Central

    Lohstroh, Pete N; Chen, Jiangang; Ba, Jianming; Ryan, Louise M; Xu, Xiping; Overstreet, James W; Lasley, Bill L

    2003-01-01

    Stressors as subtle as night work or shift work can lead to irregular menstrual cycles, and changes in reproductive hormone profiles can adversely affect bone health. This study was conducted to determine if stresses associated with the disruption of regular work schedule can induce alterations in ovarian function which, in turn, are associated with transient bone resorption. Urine samples from 12 rotating shift workers from a textile mill in Anqing, China, were collected in 1996-1998 during pairs of sequential menstrual cycles, of which one was longer than the other (28.4 vs. 37.4 days). Longer cycles were characterized by a prolonged follicular phase. Work schedules during the luteal-follicular phase transition (LFPT) preceding each of the two cycles were evaluated. All but one of the shorter cycles were associated with regular, forward phase work shift progression during the preceding LFPT. In contrast, five longer cycles were preceded by a work shift interrupted either by an irregular shift or a number of "off days." Urinary follicle-stimulating hormone levels were reduced in the LFPT preceding longer cycles compared with those in the LFPT preceding shorter cycles. There was greater bone resorption in the follicular phase of longer cycles than in that of shorter cycles, as measured by urinary deoxypyridinoline. These data confirm reports that changes in work shift can lead to irregularity in menstrual cycle length. In addition, these data indicate that there may be an association between accelerated bone resorption in menstrual cycles and changes of regularity in work schedule during the preceding LFPT. PMID:12676625

  5. Assessment of bone formation and bone resorption in osteoporosis: a comparison between tetracycline-based iliac histomorphometry and whole body /sup 85/Sr kinetics

    SciTech Connect

    Reeve, J.; Arlot, M.E.; Chavassieux, P.M.; Edouard, C.; Green, J.R.; Hesp, R.; Tellez, M.; Meunier, P.J.

    1987-12-01

    Bone formation and resorption have been measured in patients with idiopathic osteoporosis by histomorphometry of 7.5-mm trephine biopsies and in the whole body by 85Sr radiotracer methodology and calcium balances. The studies were synchronized and most were preceded by double in vivo tetracycline labeling. Correlations between histological and kinetic bone formation indices were better when better when based on the extent of double tetracycline labels than on measurements of osteoid by visible light microscopy. Correction of the kinetic data for long-term exchange, using 5 months' serial whole body counting of retained 85Sr, improved the fit of the kinetic to the histological data. A statistical analysis of the measurement uncertainties showed that the residual scatter in the best correlations (between exchange-corrected bone formation rates and double-labeled osteoid surface indices) could be attributed to measurement imprecision alone. The exchange-corrected resorption rate correlated fairly well with iliac trabecular resorption surfaces, and using a volume referent rather than a surface referent for the histological index improved the statistical fit when patients with therapeutically accelerated bone turnover were included. A much better correlation was obtained by including osteoid volume acting as an independent predictor of bone resorption in a bivariate regression with a resorption surface index. The residual errors could then be accounted for by known measurement uncertainties. Whereas osteoid taking a double label closely predicted the kinetic rate of bone formation, further analysis suggested that osteoid that took no label or a single label was more closely related to bone resorption, presumably as a secondary result of the coupling of bone formation to bone resorption.

  6. Insulin-like growth factor-1 receptor in mature osteoblasts is required for periosteal bone formation induced by reloading.

    PubMed

    Kubota, Takuo; Elalieh, Hashem Z; Saless, Neema; Fong, Chak; Wang, Yongmei; Babey, Muriel; Cheng, Zhiqiang; Bikle, Daniel D

    2013-11-01

    Skeletal loading and unloading has a pronounced impact on bone remodeling, a process also regulated by insulin-like growth factor 1 (IGF-1) signaling. Skeletal unloading leads to resistance to the anabolic effect of IGF-1, while reloading after unloading restores responsiveness to IGF-1. However, a direct study of the importance of IGF-1 signaling in the skeletal response to mechanical loading remains to be tested. In this study, we assessed the skeletal response of osteoblast-specific Igf-1 receptor deficient (Igf-1r(-/-) ) mice to unloading and reloading. The mice were hindlimb unloaded for 14 days and then reloaded for 16 days. Igf-1r(-/-) mice displayed smaller cortical bone and diminished periosteal and endosteal bone formation at baseline. Periosteal and endosteal bone formation decreased with unloading in Igf-1r(+/+) mice. However, the recovery of periosteal bone formation with reloading was completely inhibited in Igf-1r(-/-) mice, although reloading-induced endosteal bone formation was not hampered. These changes in bone formation resulted in the abolishment of the expected increase in total cross-sectional area with reloading in Igf-1r(-/-) mice compared to the control mice. These results suggest that the Igf-1r in mature osteoblasts has a critical role in periosteal bone formation in the skeletal response to mechanical loading.

  7. Insulin-like growth factor-1 receptor in mature osteoblasts is required for periosteal bone formation induced by reloading

    NASA Astrophysics Data System (ADS)

    Kubota, Takuo; Elalieh, Hashem Z.; Saless, Neema; Fong, Chak; Wang, Yongmei; Babey, Muriel; Cheng, Zhiqiang; Bikle, Daniel D.

    2013-11-01

    Skeletal loading and unloading has a pronounced impact on bone remodeling, a process also regulated by insulin-like growth factor-1 (IGF-1) signaling. Skeletal unloading leads to resistance to the anabolic effect of IGF-1, while reloading after unloading restores responsiveness to IGF-1. However, a direct study of the importance of IGF-1 signaling in the skeletal response to mechanical loading remains to be tested. In this study, we assessed the skeletal response of osteoblast-specific Igf-1 receptor deficient (Igf-1r-/-) mice to unloading and reloading. The mice were hindlimb unloaded for 14 days and then reloaded for 16 days. Igf-1r-/- mice displayed smaller cortical bone and diminished periosteal and endosteal bone formation at baseline. Periosteal and endosteal bone formation decreased with unloading in Igf-1r+/+ mice. However, the recovery of periosteal bone formation with reloading was completely inhibited in Igf-1r-/- mice, although reloading-induced endosteal bone formation was not hampered. These changes in bone formation resulted in the abolishment of the expected increase in total cross-sectional area with reloading in Igf-1r-/- mice compared to the control mice. These results suggest that the Igf-1r in mature osteoblasts has a critical role in periosteal bone formation in the skeletal response to mechanical loading.

  8. Flat bones and sutures formation in the human cranial vault during prenatal development and infancy: A computational model.

    PubMed

    Burgos-Flórez, F J; Gavilán-Alfonso, M E; Garzón-Alvarado, D A

    2016-03-21

    The processes of flat bones growth, sutures formation and interdigitation in the human calvaria are controlled by a complex interaction between genetic, biochemical and environmental factors that regulate bone formation and resorption during prenatal development and infancy. Despite previous experimental evidence accounting for the role of the main biochemical factors acting on these processes, the underlying mechanisms controlling them are still unknown. Therefore, we propose a mathematical model of the processes of flat bone and suture formation, taking into account several biological events. First, we model the growth of the flat bones and the formation of sutures and fontanels as a reaction diffusion system between two proteins: TGF-β2 and TGF-β3. The former is expressed by osteoblasts and allows adjacent mesenchymal cells differentiation on the bone fronts of each flat bone. The latter is expressed by mesenchymal cells at the sutures and inhibits their differentiation into osteoblasts at the bone fronts. Suture interdigitation is modelled using a system of reaction diffusion equations that develops spatio-temporal patterns of bone formation and resorption by means of two molecules (Wnt and Sclerostin) which control mesenchymal cells differentiation into osteoblasts at these sites. The results of the computer simulations predict flat bone growth from ossification centers, sutures and fontanels formation as well as bone formation and resorption events along the sutures, giving rise to interdigitated patterns. These stages were modelled and solved by the finite elements method. The simulation results agree with the morphological characteristics of calvarial bones and sutures throughout human prenatal development and infancy.

  9. Genetic deletion of keratin 8 corrects the altered bone formation and osteopenia in a mouse model of cystic fibrosis.

    PubMed

    Le Henaff, Carole; Faria Da Cunha, Mélanie; Hatton, Aurélie; Tondelier, Danielle; Marty, Caroline; Collet, Corinne; Zarka, Mylène; Geoffroy, Valérie; Zatloukal, Kurt; Laplantine, Emmanuel; Edelman, Aleksander; Sermet-Gaudelus, Isabelle; Marie, Pierre J

    2016-04-01

    Patients with cystic fibrosis (CF) display low bone mass and alterations in bone formation. Mice carrying the F508del genetic mutation in the cystic fibrosis conductance regulator (Cftr) gene display reduced bone formation and decreased bone mass. However, the underlying molecular mechanisms leading to these skeletal defects are unknown, which precludes the development of an efficient anti-osteoporotic therapeutic strategy. Here we report a key role for the intermediate filament protein keratin 8 (Krt8), in the osteoblast dysfunctions in F508del-Cftr mice. We found that murine and human osteoblasts express Cftr and Krt8 at low levels. Genetic studies showed that Krt8 deletion (Krt8(-/-)) in F508del-Cftr mice increased the levels of circulating markers of bone formation, corrected the expression of osteoblast phenotypic genes, promoted trabecular bone formation and improved bone mass and microarchitecture. Mechanistically, Krt8 deletion in F508del-Cftr mice corrected overactive NF-κB signaling and decreased Wnt-β-catenin signaling induced by the F508del-Cftr mutation in osteoblasts. In vitro, treatment with compound 407, which specifically disrupts the Krt8-F508del-Cftr interaction in epithelial cells, corrected the abnormal NF-κB and Wnt-β-catenin signaling and the altered phenotypic gene expression in F508del-Cftr osteoblasts. In vivo, short-term treatment with 407 corrected the altered Wnt-β-catenin signaling and bone formation in F508del-Cftr mice. Collectively, the results show that genetic or pharmacologic targeting of Krt8 leads to correction of osteoblast dysfunctions, altered bone formation and osteopenia in F508del-Cftr mice, providing a therapeutic strategy targeting the Krt8-F508del-CFTR interaction to correct the abnormal bone formation and bone loss in cystic fibrosis.

  10. Bone Regeneration Mediated by BMP4-Expressing Muscle-Derived Stem Cells Is Affected by Delivery System

    PubMed Central

    Usas, Arvydas; Ho, Andrew M.; Cooper, Gregory M.; Olshanski, Anne; Peng, Hairong

    2009-01-01

    This study investigated the delivery of bone morphogenetic protein (BMP)4-secreting muscle-derived stem cells (MDSC-B4) capable of inducing bone formation in mice using collagen gel (CG), fibrin sealant (FS), and gelatin sponge carriers. After implanting these various cell-loaded scaffolds intramuscularly or into critical-size skull defects, we measured the extent of heterotopic ossification and calvarial defect healing over a 6-week period via radiographic, radiomorphometric, histological, and micro-computed tomography analyses. As expected, in the absence of MDSC-B4, there was no ectopic ossification and only minimal calvarial regeneration using each type of scaffold. Although CG and gelatin sponges loaded with BMP4-secreting cells produced the most ectopic bone, FS constructs produced bone with comparably less mineralization. In the mouse calvaria, we observed MDSC-B4-loaded scaffolds able to promote bone defect healing to a variable degree, but there were differences between these implants in the volume, shape, and morphology of regenerated bone. MDSC-B4 delivery in a gelatin sponge produced hypertrophic bone, whereas delivery in a CG and FS healed the defect with bone that closely resembled the quantity and configuration of native calvarium. In summary, hydrogels are suitable carriers for osteocompetent MDSCs in promoting bone regeneration, especially at craniofacial injury sites. PMID:19061430

  11. Functional requirement of CCN2 for intramembranous bone formation in embryonic mice

    PubMed Central

    Kawaki, Harumi; Kubota, Satoshi; Suzuki, Akiko; Yamada, Tomohiro; Matsumura, Tatsushi; Mandai, Toshiko; Yao, Mayumi; Maeda, Takeyasu; Lyons, Karen M.; Takigawa, Masaharu

    2009-01-01

    CCN2 is best known as a promoter of chondrocyte differentiation among the CCN family members, and Ccn2 null mutant mice display skeletal dysmorphisms. However, little is known concerning the roles of CCN2 during bone formation. We herein present a comparative analysis of wild-type and Ccn2 null mice to investigate the roles of CCN2 in bone development. Multiple histochemical methods were employed to analyze the effects of CCN2 deletion in vivo, and effects of CCN2 on the osteogenic response were evaluated with the isolated and cultured osteoblasts. As a result, we found a drastic reduction of the osteoblastic phenotype in Ccn2 null mutants. Importantly, addition of exogenous CCN2 promoted every step of osteoblast differentiation and rescued the attenuated activities of the Ccn2 null osteoblasts. These results suggest that CCN2 is required not only for the regulation of cartilage and subsequent events, but also for the normal intramembranous bone development. PMID:18067859

  12. Some factors affecting cyclopropane acid formation in Escherichia coli

    PubMed Central

    Knivett, V. A.; Cullen, Julia

    1965-01-01

    1. The fatty acid composition of the extractable lipids of Escherichia coli varied with growth conditions. 2. The principal fatty acids were palmitic acid, hexadecenoic acid, octadecenoic acid and the cyclopropane acids, methylenehexadecanoic acid and methyleneoctadecanoic acid. 3. Cyclopropane acid formation from monoenoic acids was increased by acid media, poor oxygen supply, or high growth temperature. 4. Cyclopropane acid formation was decreased by alkaline media, well oxygenated conditions, the presence of citrate, or lack of Mg2+. PMID:5324304

  13. Bone

    NASA Astrophysics Data System (ADS)

    Helmberger, Thomas K.; Hoffmann, Ralf-Thorsten

    The typical clinical signs in bone tumours are pain, destruction and destabilization, immobilization, neurologic deficits, and finally functional impairment. Primary malignant bone tumours are a rare entity, accounting for about 0.2% of all malignancies. Also benign primary bone tumours are in total rare and mostly asymptomatic. The most common symptomatic benign bone tumour is osteoid osteoma with an incidence of 1:2000.

  14. Cherubism Gene Sh3bp2 is Important for Optimal Bone Formation, Osteoblast Differentiation and Function

    PubMed Central

    Mukherjee, Padma M.; Wang, Chiachien J.; Chen, I-Ping; Jafarov, Toghrul; Olsen, Bjorn R.; Ueki, Yasuyoshi; Reichenberger, Ernst J.

    2012-01-01

    Introduction Cherubism is a human genetic disorder that causes bilateral symmetrical enlargement of the maxilla and mandible in children. It is caused by mutations in SH3BP2. The exact pathogenesis of the disorder is an area of active research. Sh3bp2 knock-in mice were developed by introducing a Pro416Arg mutation (Pro418Arg in humans) in the mouse genome. The osteoclast phenotype of this mouse model was recently described. Methods We examined the bone phenotype of the cherubism mouse model, the role of Sh3bp2 during bone formation, osteoblast differentiation and osteoblast function. Results We observed delays in early postnatal development of homozygous Sh3bp2KI/KI mice. Sh3bp2KI/KI mice exhibit increased growth plate thickness and significantly decreased trabecular bone thickness and reduced bone mineral density. Histomorphometric and μ-CT analyses reveal bone loss in cranial and appendicular skeleton. Sh3bp2KI/KI mice also exhibit a significant decrease in osteoid formation that indicates a defect in osteoblast function. Calvarial osteoblast cell cultures exhibit a decrease in alkaline phosphatase expression and mineralization suggesting reduced differentiation potential. Gene expression of osteoblast differentiation markers like collagen type-I, alkaline phosphatase and osteocalcin are decreased in osteoblast cultures from Sh3bp2KI/KI mice. Conclusions These data suggest that Sh3bp2 function regulates bone homeostasis not only through osteoclast-specific effects but also through effects on osteoblast differentiation and function. PMID:20691350

  15. Follistatin-like 3 is a mediator of exercise-driven bone formation and strengthening.

    PubMed

    Nam, J; Perera, P; Gordon, R; Jeong, Y H; Blazek, A D; Kim, D G; Tee, B C; Sun, Z; Eubank, T D; Zhao, Y; Lablebecioglu, B; Liu, S; Litsky, A; Weisleder, N L; Lee, B S; Butterfield, T; Schneyer, A L; Agarwal, S

    2015-09-01

    Exercise is vital for maintaining bone strength and architecture. Follistatin-like 3 (FSTL3), a member of follistatin family, is a mechanosensitive protein upregulated in response to exercise and is involved in regulating musculoskeletal health. Here, we investigated the potential role of FSTL3 in exercise-driven bone remodeling. Exercise-dependent regulation of bone structure and functions was compared in mice with global Fstl3 gene deletion (Fstl3-/-) and their age-matched Fstl3+/+ littermates. Mice were exercised by low-intensity treadmill walking. The mechanical properties and mineralization were determined by μCT, three-point bending test and sequential incorporation of calcein and alizarin complexone. ELISA, Western-blot analysis and qRT-PCR were used to analyze the regulation of FSTL3 and associated molecules in the serum specimens and tissues. Daily exercise significantly increased circulating FSTL3 levels in mice, rats and humans. Compared to age-matched littermates, Fstl3-/- mice exhibited significantly lower fracture tolerance, having greater stiffness, but lower strain at fracture and yield energy. Furthermore, increased levels of circulating FSTL3 in young mice paralleled greater strain at fracture compared to the lower levels of FSTL3 in older mice. More significantly, Fstl3-/- mice exhibited loss of mechanosensitivity and irresponsiveness to exercise-dependent bone formation as compared to their Fstl3+/+ littermates. In addition, FSTL3 gene deletion resulted in loss of exercise-dependent sclerostin regulation in osteocytes and osteoblasts, as compared to Fstl3+/+ osteocytes and osteoblasts, in vivo and in vitro. The data identify FSTL3 as a critical mediator of exercise-dependent bone formation and strengthening and point to its potential role in bone health and in musculoskeletal diseases.

  16. Follistatin-like 3 is a mediator of exercise-driven bone formation and strengthening

    PubMed Central

    Nam, J; Perera, P; Gordon, R; Jeong, Y; Blazek, AD; Kim, DG; Tee, BC; Sun, Z; Eubank, TD; Zhao, Y; Lablebecioglu, B; Liu, S; Litsky, A; Weisleder, NL; Lee, BS; Butterfield, T; Schneyer, AL; Agarwal, S

    2015-01-01

    Exercise is vital for maintaining bone strength and architecture. Follistatin like 3 (FSTL3), a member of Follistatin family, is a mechanosensitive protein upregulated in response to exercise and is involved in regulating musculoskeletal health, we investigated the potential role of FSTL3 in exercise-driven bone remodeling. Exercise-dependent regulation of bone structure and functions was compared in mice with global Fstl3 gene deletion (Fstl3−/−) and their age-matched Fstl3+/+ littermates. Mice were exercised by low-intensity treadmill walking. The mechanical properties and mineralization were determined by μCT, three-point bending test and sequential incorporation of calcein and alizarin complexone. ELISA, Western-blot analysis and qRT-PCR were used to analyze the regulation of FSTL3 and associated molecules in the serum specimens and tissues. Daily exercise significantly increased circulating FSTL3 levels in mice, rats and humans. Compared to age-matched littermates, Fstl3−/− mice exhibited significantly lower fracture tolerance, having greater stiffness, but lower strain at fracture and yield energy. Furthermore, increased levels of circulating FSTL3 in young mice paralleled greater strain at fracture compared to the lower levels of FSTL3 in older mice. More significantly, Fstl3−/− mice exhibited loss of mechanosensitivity and irresponsiveness to exercise-dependent bone formation as compared to their Fstl3+/+ littermates. In addition, FSTL3 gene deletion resulted in loss of exercise-dependent sclerostin regulation in osteocytes and osteoblasts, as compared to Fstl3+/+ osteocytes and osteoblasts, in vivo and in vitro. The data identifies FSTL3 as a critical mediator of exercise-dependent bone formation and strengthening and point to its potential role in bone health and in musculoskeletal diseases. PMID:25937185

  17. Deficiency of AXL in Bone Marrow-Derived Cells Does Not Affect Advanced Atherosclerotic Lesion Progression.

    PubMed

    Subramanian, Manikandan; Proto, Jonathan D; Matsushima, Glenn K; Tabas, Ira

    2016-12-13

    AXL, a member of the TAM (Tyro3, Axl, MerTK) family of receptors, plays important roles in cell survival, clearance of dead cells (efferocytosis), and suppression of inflammation, which are processes that critically influence atherosclerosis progression. Whereas MerTK deficiency promotes defective efferocytosis, inflammation, and plaque necrosis in advanced murine atherosclerosis, the role of Axl in advanced atherosclerosis progression is not known. Towards this end, bone marrow cells from Axl(-/-) or wild-type mice were transplanted into lethally irradiated Ldlr(-/-) mice. These chimeric mice were then fed the Western-type diet (WD) for 17 weeks. We demonstrate that lesional macrophages in WT mice express Axl but that Axl deficiency in bone marrow-derived cells does not affect lesion size, cellularity, necrosis, or inflammatory parameters in advanced atherosclerotic plaques. Moreover, apoptosis of lesional cells was unaffected, and we found no evidence of defective lesional efferocytosis. In contrast to previously reported findings with MerTK deficiency, hematopoietic cell-Axl deficiency in WD-fed Ldlr(-/-) mice does not affect the progression of advanced atherosclerosis or lesional processes associated with TAM receptor signaling. These findings suggest a heretofore unappreciated TAM receptor hierarchy in advanced atherosclerosis.

  18. Deficiency of AXL in Bone Marrow-Derived Cells Does Not Affect Advanced Atherosclerotic Lesion Progression

    PubMed Central

    Subramanian, Manikandan; Proto, Jonathan D.; Matsushima, Glenn K.; Tabas, Ira

    2016-01-01

    AXL, a member of the TAM (Tyro3, Axl, MerTK) family of receptors, plays important roles in cell survival, clearance of dead cells (efferocytosis), and suppression of inflammation, which are processes that critically influence atherosclerosis progression. Whereas MerTK deficiency promotes defective efferocytosis, inflammation, and plaque necrosis in advanced murine atherosclerosis, the role of Axl in advanced atherosclerosis progression is not known. Towards this end, bone marrow cells from Axl−/− or wild-type mice were transplanted into lethally irradiated Ldlr−/− mice. These chimeric mice were then fed the Western-type diet (WD) for 17 weeks. We demonstrate that lesional macrophages in WT mice express Axl but that Axl deficiency in bone marrow-derived cells does not affect lesion size, cellularity, necrosis, or inflammatory parameters in advanced atherosclerotic plaques. Moreover, apoptosis of lesional cells was unaffected, and we found no evidence of defective lesional efferocytosis. In contrast to previously reported findings with MerTK deficiency, hematopoietic cell-Axl deficiency in WD-fed Ldlr−/− mice does not affect the progression of advanced atherosclerosis or lesional processes associated with TAM receptor signaling. These findings suggest a heretofore unappreciated TAM receptor hierarchy in advanced atherosclerosis. PMID:27958361

  19. Metastasin S100A4 is a mediator of sex hormone-dependent formation of the cortical bone.

    PubMed

    Erlandsson, Malin C; Bian, Li; Jonsson, Ing-Marie; Andersson, Karin M; Bokarewa, Maria I

    2013-08-01

    S100A4 is a Ca-binding protein participating in regulation of cell growth, survival, and motility. Here we studied the role of S100A4 protein in sex hormone-regulated bone formation. Bone mineral density in the trabecular and cortical compartments was evaluated in female S100A4 knockout (KO), in matched wild-type (WT) counterparts, and in WT mice treated with lentiviral small hairpin RNA construct inhibiting the S100A4 gene transcription or with a nontargeting construct, by peripheral quantitative computed tomography. The effect of sex hormones on bone was measured 5 weeks after ovariectomy (OVX) and/or dehydroepiadrosterone treatment. S100A4KO had an excessive trabecular and cortical bone formation compared with the age- and sex-matched WT mice. S100A4KO had an increased periosteal circumference (P = .001), cortical thickness (P = .056), and cortical area (P = .003), which predicted 20% higher bone strength in S100A4KO (P = .013). WT mice treated with small hairpin RNA-S100A4 showed an increase of the cortical bone parameters in a fashion identical with S100A4KO mice, indicating the key role of S100A4 in the changed bone formation. S100A4KO mice had higher serum levels of osteocalcin and a higher number of osteocalcin-positive osteoblasts under the periosteum. OVX-S100A4 resulted in the loss of the cortical bone supported by high CTX-I levels, whereas no such changes were observed in OVX-WT mice. S100A4KO mice resisted the dehydroepiadrosterone -induced bone formation observed in the WT counterparts. Our study indicates that S100A4 is a regulator of bone formation, which inhibits bone excess in the estrogen-sufficient mice and prevents the cortical bone loss in the estrogen-deprived mice.

  20. Activation of the Hh pathway in periosteum-derived mesenchymal stem cells induces bone formation in vivo: implication for postnatal bone repair.

    PubMed

    Wang, Qun; Huang, Chunlan; Zeng, Fanjie; Xue, Ming; Zhang, Xinping

    2010-12-01

    While the essential role of periosteum in cortical bone repair and regeneration is well established, the molecular pathways that control the early osteogenic and chondrogenic differentiation of periosteal stem/progenitor cells during repair processes are unclear. Using a murine segmental bone graft transplantation model, we isolated a population of early periosteum-callus-derived mesenchymal stem cells (PCDSCs) from the healing autograft periosteum. These cells express typical mesenchymal stem cell markers and are capable of differentiating into osteoblasts, adipocytes, and chondrocytes. Characterization of these cells demonstrated that activation of the hedgehog (Hh) pathway effectively promoted osteogenic and chondrogenic differentiation of PCDSCs in vitro and induced bone formation in vivo. To determine the role of the Hh pathway in adult bone repair, we deleted Smoothened (Smo), the receptor that transduces all Hh signals at the onset of bone autograft repair via a tamoxifen-inducible RosaCreER mouse model. We found that deletion of Smo markedly reduced osteogenic differentiation of isolated PCDSCs and further resulted in a near 50% reduction in periosteal bone callus formation at the cortical bone junction as determined by MicroCT and histomorphometric analyses. These data strongly suggest that the Hh pathway plays an important role in adult bone repair via enhancing differentiation of periosteal progenitors and that activation of the Hh pathway at the onset of healing could be beneficial for repair and regeneration.

  1. Insight into characteristic features of cartilage growth plate as a physiological template for bone formation.

    PubMed

    Jaroszewicz, Jakub; Kosowska, Anna; Hutmacher, Dietmar; Swieszkowski, Wojciech; Moskalewski, Stanisław

    2016-02-01

    Cartilage growth plate is a natural template from both a biochemical and structural point of view and allows osteoblasts migration, proliferation, differentiation, and ultimately, bone formation. It is evolutionary adjusted to support bone formation within strictly defined spatial framework serving as an interesting model for studying more mechanistically aspects which might be important for specific scaffold-based bone tissue engineering strategies. Surprisingly little is known about the geometric features of this physiological template. To this purpose we analyzed cartilage growth plate from rat, mouse, and human costochondral junction and tibia. High-resolution X-ray tomography showed that pore size in the zone of provisional calcification was within 20 to 30 µm range and in the metaphysis in 35 to 50 µm range. The thickness of calcified longitudinal septa in zone of provisional calcification was 3 to 5 µm and in metaphysis 7 to 12 µm. The porosity varied from 84 to 88%. We observed that numerical values characteristic for cartilage growth plate were not significantly influenced by the species of origin, by the type of bone, or by age. In addition, electron microscopy of calcified fragments of longitudinal septa showed that the calcium aggregates were globular, connected with each other, and formed a shell covering cartilage matrix located within longitudinal septa.

  2. Vascular endothelial growth factor expression and bone formation in posterior glenoid fossa during stepwise mandibular advancement.

    PubMed

    Shum, Lily; Rabie, A B M; Hägg, Urban

    2004-02-01

    This study assessed the amount of vascular endothelial growth factor (VEGF) expression and related the findings to new bone formation in the posterior glenoid fossa during stepwise mandibular advancement. A total of 250 female Sprague-Dawley rats, 35 days old, were randomly divided into 10 groups, each including 5 control and 20 experimental rats. Within each group, 10 experimental rats were fitted with functional appliances with a 1-step advancement of 3.5 mm. Another 10 were fitted with stepwise appliances with an initial advancement of 2 mm and a subsequent increase to 3.5 mm on day 30. The rats in the experimental groups were killed on days 3, 7, 14, 21, 30, 33, 37, 44, 51, and 60, respectively. The matched controls were killed on the same time points. Sections (7 microm) were cut through the glenoid fossa sagittally and stained with anti-VEGF antibody. VEGF expression in the posterior glenoid fossa was evaluated with a computer-assisted image-analyzing system. Both VEGF expression and new bone formation were greater in the experimental rats than in the controls. During stepwise advancement, initial VEGF expression was less than that of 1-step advancement, but the second advancement elicited another peak on day 44. New bone formation was also less than that of 1-step advancement during early stages of stepwise advancement but then began to increase from day 37 onward. The maximum increase was observed on day 60. Stepwise advancement of the mandible delivers mechanical stimuli that produce a series of tissue responses that lead to increased vascularization and bone formation.

  3. Sequential Treatment with SDF-1 and BMP-2 Potentiates Bone Formation in Calvarial Defects.

    PubMed

    Hwang, Hee-Don; Lee, Jung-Tae; Koh, Jeong-Tae; Jung, Hong-Moon; Lee, Heon-Jin; Kwon, Tae-Geon

    2015-07-01

    Stromal cell-derived factor-1 (SDF-1) protein and its receptor, CXCR-4, play an important role in tissue repair and regeneration in various organs, including the bone. SDF-1 is indispensable for bone morphogenetic protein-2 (BMP-2)-induced osteogenic differentiation. However, SDF-1 is not needed after the osteogenic induction has been activated. Since the precise condition for the additive effects of combined DF-1 and BMP-2 in bone healing had not been fully investigated, we aimed to determine the optimal conditions for SDF-1- and BMP-2-mediated bone regeneration. We examined the in vitro osteoblastic differentiation and cell migration after sequential treatments with SDF-1 and BMP-2. Based on the in vitro additive effects of SDF-1 and BMP-2, the critical size defects of mice calvaria were treated with these cytokines in various sequences. Phosphate buffered saline (PBS)-, SDF-1-, or BMP-2-soaked collagen scaffolds were implanted into the calvarial defects (n=36). Periodic percutaneous injections of PBS or the cytokine SDF-1 and BMP-2 into the implanted scaffolds were performed on days 3 and 6, postoperatively. Six experimental groups were used according to the types and sequences of the cytokine treatments. After 28 days, the mice were euthanized and bone formation was evaluated with microcomputed tomography and histology. The molecular mechanism of the additive effect of SDF-1 and BMP-2 was evaluated by analyzing intracellular signal transduction through Smad and Erk phosphorylation. The in vitro experiments revealed that, among all the treatments, the treatment with BMP-2 after SDF-1 showed the strongest osteoblastic differentiation and enhanced cell migration. Similarly, in the animal model, the treatment with SDF-1 followed by BMP-2 treatment showed the highest degree of new bone regeneration than any other groups, including the one with continuous BMP-2 treatment. This new bone formation can be partially explained by the activation of Smad and Erk pathways

  4. Hydroxyapatite bioactivated bacterial cellulose promotes osteoblast growth and the formation of bone nodules

    PubMed Central

    2012-01-01

    The goal of this study was to investigate the feasibility of bacterial cellulose (BC) scaffold to support osteoblast growth and bone formation. BC was produced by culturing Acetobacter xylinum supplemented with hydroxyapatite (HA) to form BC membranes (without HA) and BC/HA membranes. Membranes were subjected to X-ray photoelectron spectroscopy (XPS) analysis to determine surface element composition. The membranes were further used to evaluate osteoblast growth, alkaline phosphatase activity and bone nodule formation. BC was free of calcium and phosphate. However, XPS analysis revealed the presence of both calcium (10%) and phosphate (10%) at the surface of the BC/HA membrane. Osteoblast culture showed that BC alone was non-toxic and could sustain osteoblast adhesion. Furthermore, osteoblast adhesion and growth were significantly (p ≤0.05) increased on BC/HA membranes as compared to BC alone. Both BC and BC/HA membranes improved osteoconductivity, as confirmed by the level of alkaline phosphatase (ALP) activity that increased from 2.5 mM with BC alone to 5.3 mM with BC/HA. BC/HA membranes also showed greater nodule formation and mineralization than the BC membrane alone. This was confirmed by Alizarin red staining (ARS) and energy dispersive X-ray spectroscopy (EDX). This work demonstrates that both BC and BC/HA may be useful in bone tissue engineering. PMID:23174338

  5. Short-term aluminum administration in the rat. Effects on bone formation and relationship to renal osteomalacia.

    PubMed Central

    Goodman, W G; Gilligan, J; Horst, R

    1984-01-01

    Aluminum may be pathogenic in the osteomalacia observed in some patients receiving hemodialysis. To study the early effects of Al on bone growth, bone formation, mineralization, and resorption were measured during short-term Al exposure in the tibial cortex of pair-fed control (C, n = 10), aluminum-treated (AL, n = 9), subtotally nephrectomized control (NX-C, n = 7), and subtotally nephrectomized aluminum-treated (NX-AL, n = 8) rats using double tetracycline labeling of bone. Animals received 2 mg/d of elemental Al intraperitoneally for 5 d/wk over 4 wk. Total bone and matrix (osteoid) formation, periosteal bone and matrix formation, and periosteal bone and matrix apposition fell by 20% in AL from C, P less than 0.05 for all values, and by 40% in NX-AL from NX-C, P less than 0.01 for all values. Moreover, each measurement was significantly less in NX-AL than in AL, P less than 0.05 for all values. Osteoid width did not increase following aluminum administration in either AL or NX-AL. Resorption surface increased from control values in both AL and NX-AL; also, resorptive activity at the endosteum was greater in NX-AL than in NX-C, P less than 0.05. Thus, aluminum impairs new bone and matrix formation but does not cause classic osteomalacia in the cortical bone of rats whether renal function is normal or reduced. These findings may represent either a different response to aluminum administration in cortical bone as contrasted to trabecular bone or an early phase in the development of osteomalacia. Aluminum may increase bone resorption and contribute to osteopenia in clinical states associated with aluminum accumulation in bone. PMID:6690476

  6. The C-terminal fragment of parathyroid hormone-related peptide promotes bone formation in diabetic mice with low-turnover osteopaenia

    PubMed Central

    Lozano, D; Fernández-de-Castro, L; Portal-Núñez, S; López-Herradón, A; Dapía, S; Gómez-Barrena, E; Esbrit, P

    2011-01-01

    BACKGROUND AND PURPOSE Current data suggest that parathyroid hormone (PTH)-related peptide (PTHrP) domains other than the N-terminal PTH-like domain contribute to its role as an endogenous bone anabolic factor. PTHrP-107-139 inhibits bone resorption, a fact which has precluded an unequivocal demonstration of its possible anabolic action in vivo. We thus sought to characterize the osteogenic effects of this peptide using a mouse model of diabetic low-turnover osteopaenia. EXPERIMENTAL APPROACH PTHrP-107-139 was administered to streptozotocin-induced diabetic mice, with or without bone marrow ablation, for 13 days. Osteopaenia was confirmed by dual-energy X-ray absorptiometry and microcomputed tomography analysis. Histological analysis was performed on paraffin-embedded bone tissue sections by haematoxylin/eosin and Masson's staining, and tartrate-resistent acid phosphatase immunohistochemistry. Mouse bone marrow stromal cells and osteoblastic MC3T3-E1 cells were cultured in normal and/or high glucose (HG) medium. Osteogenic and adipogenic markers were assessed by real-time PCR, and PTHrP and the PTH1 receptor protein expression by Western blot analysis. KEY RESULTS PTHrP-107-139 reversed the alterations in bone structure and osteoblast function, and also promoted bone healing after marrow ablation without affecting the number of osteoclast-like cells in diabetic mice. This peptide also reversed the high-glucose-induced changes in osteogenic differentiation in both bone marrow stromal cells and the more differentiated MC3T3-E1 cells. CONCLUSIONS AND IMPLICATIONS These findings demonstrate that PTHrP-107-139 promotes bone formation in diabetic mice. This mouse model and in vitro cell cultures allowed us to identify various anabolic effects of this peptide in this scenario. PMID:21175568

  7. Enhancing in vivo vascularized bone formation by cobalt chloride-treated bone marrow stromal cells in a tissue engineered periosteum model.

    PubMed

    Fan, Wei; Crawford, Ross; Xiao, Yin

    2010-05-01

    The periosteum plays an indispensable role in both bone formation and bone defect healing. In this study we constructed an artificial in vitro periosteum by incorporating osteogenic differentiated bone marrow stromal cells (BMSCs) and cobalt chloride (CoCl(2))-treated BMSCs. The engineered periostea were implanted both subcutaneously and into skull bone defects in SCID mice to investigate ectopic and orthotopic osteogenesis and vascularization. After two weeks in subcutaneous and four weeks in bone defect areas, the implanted constructs were assessed for ectopic and orthotopic osteogenesis and vascularization by micro-CT, histomorphometrical and immunohistochemical methods. The results showed that CoCl(2) pre-treated BMSCs induced higher degree of vascularization and enhanced osteogenesis within the implants in both ectopic and orthotopic areas. This study provided a novel approach using BMSCs sourced from the same patient for both osteogenic and pro-angiogenic purposes in constructing tissue engineered periosteum to enhance vascularized osteogenesis.

  8. AGE-RELATED FACTORS AFFECTING THE POST-YIELD ENERGY DISSIPATION OF HUMAN CORTICAL BONE

    PubMed Central

    Nyman, Jeffry S.; Roy, Anuradha; Tyler, Jerrod H.; Acuna, Rae L.; Gayle, Heather J.; Wang, Xiaodu

    2007-01-01

    The risk of bone fracture depends in part on the quality of the tissue, not just the size and mass. This study assessed the post-yield energy dissipation of cortical bone in tension as a function of age and composition. Tensile specimens were prepared from tibiae of human cadavers in which male and female donors were divided into two age groups: middle aged (51 to 56 years old, n = 9) and elderly (72 to 90 years old, n = 8). By loading, unloading, and reloading a specimen with rest period inserted in between, tensile properties at incremental strain levels were assessed. In addition, the post-yield toughness was estimated and partitioned as follows: plastic strain energy related to permanent deformation, released elastic strain energy related to stiffness loss, and hysteresis energy related to viscous behavior. Porosity, mineral and collagen content, and collagen crosslinks of each specimen were also measured to determine the micro and ultrastructural properties of the tissue. It was found that age affected all the energy terms plus strength but not elastic stiffness. The post-yield energy terms were correlated with porosity, pentosidine (a marker of non-enzymatic crosslinks), and collagen content, all of which significantly varied with age. General linear models with the highest possible R2 value suggested that the pentosidine concentration and collagen content provided the best explanation of the age-related decrease in the post-yield energy dissipation of bone. Among them, pentosidine concentration had the greatest contribution to plastic strain energy and was the best explanatory variable of damage accumulation. PMID:17266142

  9. 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.

  10. Effects of calcium phosphate/chitosan composite on bone healing in rats: calcium phosphate induces osteon formation.

    PubMed

    Fernández, Tulio; Olave, Gilberto; Valencia, Carlos H; Arce, Sandra; Quinn, Julian M W; Thouas, George A; Chen, Qi-Zhi

    2014-07-01

    Vascularization of an artificial graft represents one of the most significant challenges facing the field of bone tissue engineering. Over the past decade, strategies to vascularize artificial scaffolds have been intensively evaluated using osteoinductive calcium phosphate (CaP) biomaterials in animal models. In this work, we observed that CaP-based biomaterials implanted into rat calvarial defects showed remarkably accelerated formation and mineralization of new woven bone in defects in the initial stages, at a rate of ∼60 μm/day (0.8 mg/day), which was considerably higher than normal bone growth rates (several μm/day, 0.1 mg/day) in implant-free controls of the same age. Surprisingly, we also observed histological evidence of primary osteon formation, indicated by blood vessels in early-region fibrous tissue, which was encapsulated by lamellar osteocyte structures. These were later fully replaced by compact bone, indicating complete regeneration of calvarial bone. Thus, the CaP biomaterial used here is not only osteoinductive, but vasculogenic, and it may have contributed to the bone regeneration, despite an absence of osteons in normal rat calvaria. Further investigation will involve how this strategy can regulate formation of vascularized cortical bone such as by control of degradation rate, and use of models of long, dense bones, to more closely approximate repair of human cortical bone.

  11. Exploring How Giant Planet Formation Affected the Asteroid Belt

    NASA Astrophysics Data System (ADS)

    Kretke, Katherine A.; Levison, Harold F.; Bottke, William

    2016-10-01

    The asteroid belt is observed to be a mixture of objects with different compositions, with volatile-poor asteroids (mostly S-complex) dominant in the inner asteroid belt while volatile-rich (mostly C-complex) asteroids dominate the outer asteroid belt. While this general compositional stratification was originally thought to be an indicator of the primordial temperature gradient in the protoplanetary disk, the very distinct properties of these populations suggest that they must represent two completely decoupled reservoirs, not a simple gradient (e.g., Warren 2011). It is possible to create this general stratification (as well as the observed mixing) as the implantation of outer Solar System material into the asteroid belt by the early migration of the giant planets (e.g. the Grand Tack, Walsh et al. 2011). However, this presupposes that the inner and outer Solar System materials were still sorted in their primordial locations prior to any migration of the planets. The lack of a fully dynamically self-consistent model of giant planet core formation has prevented the study of how the core formation process itself may result in dynamical mixing in the early Solar System's history. Recently, pebble accretion, the process by which planetesimals can grow to giant planet cores via the accretion of small, rapidly drifting sub-meter-sized bodies known as ``pebbles,'' (Lambrechts & Johansen 2012, Levison, Kretke & Duncan 2015) finally offers such a model. Here we show how the process of giant planet formation will impact the surrounding planetesimal population, possibly resulting in the observed compositional mixture of the asteroid belt, without requiring a dramatic migration of the giant planets. For example, preliminary runs suggest planetesimals from the Jupiter-formation zone can be implanted in the outer main belt via interactions with scattered Jupiter-zone protoplanets. This could potentially provide an alternative non-Grand Tack solution to the origin of many C

  12. Changes in markers of bone formation and resorption in a bed rest model of weightlessness

    NASA Technical Reports Server (NTRS)

    Lueken, S. A.; Arnaud, S. B.; Taylor, A. K.; Baylink, D. J.

    1993-01-01

    To study the mechanism of bone loss in physical unloading, we examined indices of bone formation and bone resorption in the serum and urine of eight healthy men during a 7 day -6 degrees head-down tilt bed rest. Prompt increases in markers of resorption--pyridinoline (PD), deoxypyridinoline (DPD), and hydroxyproline (Hyp)/g creatinine--during the first few days of inactivity were paralleled by tartrate-resistant acid phosphatase (TRAP) with significant increases in all these markers by day 4 of bed rest. An index of formation, skeletal alkaline phosphatase (SALP), did not change during bed rest and showed a moderate 15% increase 1 week after reambulation. In contrast to SALP, serum osteocalcin (OC) began increasing the day preceding the increase in Hyp, remained elevated for the duration of the bed rest, and returned to pre-bed rest values within 5 days of reambulation. Similarly, DPD increased significantly at the onset of bed rest, remained elevated for the duration of bed rest, and returned to pre-bed rest levels upon reambulation. On the other hand, the other three indices of resorption, Hyp, PD, and TRAP, remained elevated for 2 weeks after reambulation. The most sensitive indices of the levels of physical activity proved to be the noncollagenous protein, OC, and the collagen crosslinker, DPD. The bed rest values of both these markers were significantly elevated compared to both the pre-bed rest values and the post-bed rest values. The sequence of changes in the circulating markers of bone metabolism indicated that increases in serum OC are the earliest responses of bone to head-down tilt bed rest.

  13. Glycation of Human Cortical and Cancellous Bone Captures Differences in the Formation of Maillard Reaction Products between Glucose and Ribose

    PubMed Central

    Sroga, Grażyna E.; Siddula, Alankrita; Vashishth, Deepak

    2015-01-01

    To better understand some aspects of bone matrix glycation, we used an in vitro glycation approach. Within two weeks, our glycation procedures led to the formation of advanced glycation end products (AGEs) at the levels that corresponded to approx. 25–30 years of the natural in vivo glycation. Cortical and cancellous bones from human tibias were glycated in vitro using either glucose (glucosylation) or ribose (ribosylation). Both glucosylation and ribosylation led to the formation of higher levels of AGEs and pentosidine (PEN) in cancellous than cortical bone dissected from all tested donors (young, middle-age and elderly men and women). More efficient glycation of bone matrix proteins in cancellous bone most likely depended on the higher porosity of this tissue, which facilitated better accessibility of the sugars to the matrix proteins. Notably, glycation of cortical bone from older donors led to much higher AGEs levels as compared to young donors. Such efficient in vitro glycation of older cortical bone could result from aging-related increase in porosity caused by the loss of mineral content. In addition, more pronounced glycation in vivo would be driven by elevated oxidation processes. Interestingly, the levels of PEN formation differed pronouncedly between glucosylation and ribosylation. Ribosylation generated very high levels of PEN (approx. 6- vs. 2.5-fold higher PEN level than in glucosylated samples). Kinetic studies of AGEs and PEN formation in human cortical and cancellous bone matrix confirmed higher accumulation of fluorescent crosslinks for ribosylation. Our results suggest that in vitro glycation of bone using glucose leads to the formation of lower levels of AGEs including PEN, whereas ribosylation appears to support a pathway toward PEN formation. Our studies may help to understand differences in the progression of bone pathologies related to protein glycation by different sugars, and raise awareness for excessive sugar supplementation in food

  14. Influence of Interleukin-1 Beta on Platelet-Poor Plasma Clot Formation: A Potential Impact on Early Bone Healing

    PubMed Central

    Masci, Paul P.; Crawford, Ross; Xiao, Yin

    2016-01-01

    Objectives Hematoma quality (especially the fibrin matrix) plays an important role in the bone healing process. Here, we investigated the effect of interleukin-1 beta (IL-1β) on fibrin clot formation from platelet-poor plasma (PPP). Methods Five-milliliter of rat whole-blood samples were collected from the hepatic portal vein. All blood samples were firstly standardized via a thrombelastograph (TEG), blood cell count, and the measurement of fibrinogen concentration. PPP was prepared by collecting the top two-fifths of the plasma after centrifugation under 400 × g for 10 min at 20°C. The effects of IL-1β cytokines on artificial fibrin clot formation from PPP solutions were determined by scanning electronic microscopy (SEM), confocal microscopy (CM), turbidity, and clot lysis assays. Results The lag time for protofibril formation was markedly shortened in the IL-1β treatment groups (243.8 ± 76.85 in the 50 pg/mL of IL-1β and 97.5 ± 19.36 in the 500 pg/mL of IL-1β) compared to the control group without IL-1β (543.8 ± 205.8). Maximal turbidity was observed in the control group. IL-1β (500 pg/mL) treatment significantly decreased fiber diameters resulting in smaller pore sizes and increased density of the fibrin clot structure formed from PPP (P < 0.05). The clot lysis assay revealed that 500 pg/mL IL-1β induced a lower susceptibility to dissolution due to the formation of thinner and denser fibers. Conclusion IL-1β can significantly influence PPP fibrin clot structure, which may affect the early bone healing process. PMID:26909757

  15. EPO Promotes Bone Repair through Enhanced Cartilaginous Callus Formation and Angiogenesis

    PubMed Central

    Wan, Lin; Zhang, Fengjie; He, Qiling; Tsang, Wing Pui; Lu, Li; Li, Qingnan; Wu, Zhihong; Qiu, Guixing; Zhou, Guangqian; Wan, Chao

    2014-01-01

    Erythropoietin (EPO)/erythropoietin receptor (EPOR) signaling is involved in the development and regeneration of several non-hematopoietic tissues including the skeleton. EPO is identified as a downstream target of the hypoxia inducible factor-α (HIF-α) pathway. It is shown that EPO exerts a positive role in bone repair, however, the underlying cellular and molecular mechanisms remain unclear. In the present study we show that EPO and EPOR are expressed in the proliferating, pre-hypertrophic and hypertrophic zone of the developing mouse growth plates as well as in the cartilaginous callus of the healing bone. The proliferation rate of chondrocytes is increased under EPO treatment, while this effect is decreased following siRNA mediated knockdown of EPOR in chondrocytes. EPO treatment increases biosynthesis of proteoglycan, accompanied by up-regulation of chondrogenic marker genes including SOX9, SOX5, SOX6, collagen type 2, and aggrecan. The effects are inhibited by knockdown of EPOR. Blockage of the endogenous EPO in chondrocytes also impaired the chondrogenic differentiation. In addition, EPO promotes metatarsal endothelial sprouting in vitro. This coincides with the in vivo data that local delivery of EPO increases vascularity at the mid-stage of bone healing (day 14). In a mouse femoral fracture model, EPO promotes cartilaginous callus formation at days 7 and 14, and enhances bone healing at day 28 indexed by improved X-ray score and micro-CT analysis of microstructure of new bone regenerates, which results in improved biomechanical properties. Our results indicate that EPO enhances chondrogenic and angiogenic responses during bone repair. EPO's function on chondrocyte proliferation and differentiation is at least partially mediated by its receptor EPOR. EPO may serve as a therapeutic agent to facilitate skeletal regeneration. PMID:25003898

  16. EPO promotes bone repair through enhanced cartilaginous callus formation and angiogenesis.

    PubMed

    Wan, Lin; Zhang, Fengjie; He, Qiling; Tsang, Wing Pui; Lu, Li; Li, Qingnan; Wu, Zhihong; Qiu, Guixing; Zhou, Guangqian; Wan, Chao

    2014-01-01

    Erythropoietin (EPO)/erythropoietin receptor (EPOR) signaling is involved in the development and regeneration of several non-hematopoietic tissues including the skeleton. EPO is identified as a downstream target of the hypoxia inducible factor-α (HIF-α) pathway. It is shown that EPO exerts a positive role in bone repair, however, the underlying cellular and molecular mechanisms remain unclear. In the present study we show that EPO and EPOR are expressed in the proliferating, pre-hypertrophic and hypertrophic zone of the developing mouse growth plates as well as in the cartilaginous callus of the healing bone. The proliferation rate of chondrocytes is increased under EPO treatment, while this effect is decreased following siRNA mediated knockdown of EPOR in chondrocytes. EPO treatment increases biosynthesis of proteoglycan, accompanied by up-regulation of chondrogenic marker genes including SOX9, SOX5, SOX6, collagen type 2, and aggrecan. The effects are inhibited by knockdown of EPOR. Blockage of the endogenous EPO in chondrocytes also impaired the chondrogenic differentiation. In addition, EPO promotes metatarsal endothelial sprouting in vitro. This coincides with the in vivo data that local delivery of EPO increases vascularity at the mid-stage of bone healing (day 14). In a mouse femoral fracture model, EPO promotes cartilaginous callus formation at days 7 and 14, and enhances bone healing at day 28 indexed by improved X-ray score and micro-CT analysis of microstructure of new bone regenerates, which results in improved biomechanical properties. Our results indicate that EPO enhances chondrogenic and angiogenic responses during bone repair. EPO's function on chondrocyte proliferation and differentiation is at least partially mediated by its receptor EPOR. EPO may serve as a therapeutic agent to facilitate skeletal regeneration.

  17. Ultrasound mimics the effect of mechanical loading on bone formation in vivo on rat ulnae.

    PubMed

    Perry, Mark J; Parry, Laura K; Burton, Victoria J; Gheduzzi, Sabina; Beresford, Jon N; Humphrey, Victor F; Skerry, Tim M

    2009-01-01

    While the effect of ultrasound as an extreme example of low-magnitude high-frequency stimulation has been explored in the response of bone to injury, little is known about its effect on normal bone. This experiment was designed to test the hypothesis that ultrasound exerts a similar influence on bone as mechanical stimulation at a physiological level. Three groups of female Wistar rats were anaesthetised (6 per group). In one group, the left ulna was loaded cyclically in vivo 40 times, repeated on a further 5 occasions on alternate days. In a second group, transcutaneous low-intensity pulsed ultrasound stimulation was applied to the left ulnae for the same duration as the period of loading. In a third group, loading and ultrasound stimulation were applied concurrently. The right ulna served as non-loaded control in each animal. At the end of the experiment after 14 days, both ulnae were removed. Induced bone formation was assessed by measuring the proportion of medial periosteal bone surface with double label (dLS/BS, %) and by calculation of mineral apposition rate (MAR) from the inter-label distance. All three treatments induced a significant periosteal response, increasing dLS/BS values from <10% in control limbs to >80% in treated limbs. Increases in MAR of experimental ulnae versus contralateral control ulnae were 2.9 (+/-0.9), 8.6 (+/-2.4) and 8.7 microm (+/-3.2) for the ultrasound only, ultrasound and load, and load only groups, respectively. The effects of loading plus ultrasound were not significantly different from ultrasound alone. These data suggest that ultrasound is able to induce changes in bone that share at least some features with mechanical loading.

  18. Effects of Recombinant Human Bone Morphogenetic Protein-2 Dose and Ceramic Composition on New Bone Formation and Space Maintenance in a Canine Mandibular Ridge Saddle Defect Model

    PubMed Central

    Talley, Anne D.; Kalpakci, Kerem N.; Shimko, Daniel A.; Zienkiewicz, Katarzyna J.; Cochran, David L.

    2016-01-01

    Treatment of mandibular osseous defects is a significant clinical challenge. Maintenance of the height and width of the mandibular ridge is essential for placement of dental implants and restoration of normal dentition. While guided bone regeneration using protective membranes is an effective strategy for maintaining the anatomic contour of the ridge and promoting new bone formation, complications have been reported, including wound failure, seroma, and graft exposure leading to infection. In this study, we investigated injectable low-viscosity (LV) polyurethane/ceramic composites augmented with 100 μg/mL (low) or 400 μg/mL (high) recombinant human bone morphogenetic protein-2 (rhBMP-2) as space-maintaining bone grafts in a canine mandibular ridge saddle defect model. LV grafts were injected as a reactive paste that set in 5–10 min to form a solid porous composite with bulk modulus exceeding 1 MPa. We hypothesized that compression-resistant LV grafts would enhance new bone formation and maintain the anatomic contour of the mandibular ridge without the use of protective membranes. At the rhBMP-2 dose recommended for the absorbable collagen sponge carrier in dogs (400 μg/mL), LV grafts maintained the width and height of the host mandibular ridge and supported new bone formation, while at suboptimal (100 μg/mL) doses, the anatomic contour of the ridge was not maintained. These findings indicate that compression-resistant bone grafts with bulk moduli exceeding 1 MPa and rhBMP-2 doses comparable to that recommended for the collagen sponge carrier support new bone formation and maintain ridge height and width in mandibular ridge defects without protective membranes. PMID:26800574

  19. Extractable bone morphogenetic protein and correlation with induced new bone formation in an in vivo assay in the athymic mouse model.

    PubMed

    Honsawek, Sittisak; Powers, Ralph M; Wolfinbarger, Lloyd

    2005-01-01

    A correlation between extractable bone morphogenetic proteins (BMPs) in demineralized bone matrix (DBM) and osteoinduction has been suggested. Extractable BMP-4 and osteoinductivity of DBM from 40 donors were assessed using enzyme-linked immunosorbent assay (ELISA) and in vivo athymic mouse assay, respectively. Extractable BMP-4 level averaged 3.7 +/- 0.21 ng/g of DBM and correlated with osteoinductivity of the DBM in an in vivo assessment of induced newbone formation.

  20. Bone morphogenetic protein-2 gene controls tooth root development in coordination with formation of the periodontium

    PubMed Central

    Rakian, Audrey; Yang, Wu-Chen; Gluhak-Heinrich, Jelica; Cui, Yong; Harris, Marie A; Villarreal, Demitri; Feng, Jerry Q; MacDougall, Mary; Harris, Stephen E

    2013-01-01

    Formation of the periodontium begins following onset of tooth-root formation in a coordinated manner after birth. Dental follicle progenitor cells are thought to form the cementum, alveolar bone and Sharpey's fibers of the periodontal ligament (PDL). However, little is known about the regulatory morphogens that control differentiation and function of these progenitor cells, as well as the progenitor cells involved in crown and root formation. We investigated the role of bone morphogenetic protein-2 (Bmp2) in these processes by the conditional removal of the Bmp2 gene using the Sp7-Cre-EGFP mouse model. Sp7-Cre-EGFP first becomes active at E18 in the first molar, with robust Cre activity at postnatal day 0 (P0), followed by Cre activity in the second molar, which occurs after P0. There is robust Cre activity in the periodontium and third molars by 2 weeks of age. When the Bmp2 gene is removed from Sp7+ (Osterix+) cells, major defects are noted in root, cellular cementum and periodontium formation. First, there are major cell autonomous defects in root-odontoblast terminal differentiation. Second, there are major alterations in formation of the PDLs and cellular cementum, correlated with decreased nuclear factor IC (Nfic), periostin and α-SMA+ cells. Third, there is a failure to produce vascular endothelial growth factor A (VEGF-A) in the periodontium and the pulp leading to decreased formation of the microvascular and associated candidate stem cells in the Bmp2-cKOSp7-Cre-EGFP. Fourth, ameloblast function and enamel formation are indirectly altered in the Bmp2-cKOSp7-Cre-EGFP. These data demonstrate that the Bmp2 gene has complex roles in postnatal tooth development and periodontium formation. PMID:23807640

  1. Efficiently engineered cell sheet using a complex of polyethylenimine–alginate nanocomposites plus bone morphogenetic protein 2 gene to promote new bone formation

    PubMed Central

    Jin, Han; Zhang, Kai; Qiao, Chunyan; Yuan, Anliang; Li, Daowei; Zhao, Liang; Shi, Ce; Xu, Xiaowei; Ni, Shilei; Zheng, Changyu; Liu, Xiaohua; Yang, Bai; Sun, Hongchen

    2014-01-01

    Regeneration of large bone defects is a common clinical problem. Recently, stem cell sheet has been an emerging strategy in bone tissue engineering. To enhance the osteogenic potential of stem cell sheet, we fabricated bone morphogenetic protein 2 (BMP-2) gene-engineered cell sheet using a complex of polyethylenimine–alginate (PEI–al) nanocomposites plus human BMP-2 complementary(c)DNA plasmid, and studied its osteogenesis in vitro and in vivo. PEI–al nanocomposites carrying BMP-2 gene could efficiently transfect bone marrow mesenchymal stem cells. The cell sheet was made by culturing the cells in medium containing vitamin C for 10 days. Assays on the cell culture showed that the genetically engineered cells released the BMP-2 for at least 14 days. The expression of osteogenesis-related gene was increased, which demonstrated that released BMP-2 could effectively induce the cell sheet osteogenic differentiation in vitro. To further test the osteogenic potential of the cell sheet in vivo, enhanced green fluorescent protein or BMP-2-producing cell sheets were treated on the cranial bone defects. The results indicated that the BMP-2-producing cell sheet group was more efficient than other groups in promoting bone formation in the defect area. Our results suggested that PEI–al nanocomposites efficiently deliver the BMP-2 gene to bone marrow mesenchymal stem cells and that BMP-2 gene-engineered cell sheet is an effective way for promoting bone regeneration. PMID:24855355

  2. Parameters affecting the formation of perfluoroalkyl acids during wastewater treatment.

    PubMed

    Guerra, P; Kim, M; Kinsman, L; Ng, T; Alaee, M; Smyth, S A

    2014-05-15

    This study examined the fate and behaviour of perfluoroalkyl acids (PFAAs) in liquid and solid samples from five different wastewater treatment types: facultative and aerated lagoons, chemically assisted primary treatment, secondary aerobic biological treatment, and advanced biological nutrient removal treatment. To the best of our knowledge, this is the largest data set from a single study available in the literature to date for PFAAs monitoring study in wastewater treatment. Perfluorooctanoic acid (PFOA) was the predominant PFAA in wastewater with levels from 2.2 to 150ng/L (influent) and 1.9 to 140ng/L (effluent). Perfluorooctanesulfonic acid (PFOS) was the predominant compound in primary sludge, waste biological sludge, and treated biosolids with concentrations from 6.4 to 2900ng/g dry weight (dw), 9.7 to 8200ng/gdw, and 2.1 to 17,000ng/gdw, respectively. PFAAs were formed during wastewater treatment and it was dependant on both process temperature and treatment type; with higher rates of formation in biological wastewater treatment plants (WWTPs) operating at longer hydraulic retention times and higher temperatures. PFAA removal by sorption was influenced by different sorption tendencies; median log values of the solid-liquid distribution coefficient estimated from wastewater biological sludge and final effluent were: PFOS (3.73)>PFDA (3.68)>PFNA (3.25)>PFOA (2.49)>PFHxA (1.93). Mass balances confirmed the formation of PFAAs, low PFAA removal by sorption, and high PFAA levels in effluents.

  3. Staphylococcal biofilm formation as affected by type acidulant.

    PubMed

    Nostro, Antonia; Cellini, Luigina; Ginestra, Giovanna; D'Arrigo, Manuela; di Giulio, Mara; Marino, Andreana; Blanco, Anna Rita; Favaloro, Angelo; Bisignano, Giuseppe

    2014-07-01

    Staphylococcal growth and biofilm formation in culture medium where pH was lowered with weak organic (acetic and lactic) or strong inorganic (hydrochloric) acids were studied. The effects were evaluated by biomass measurements, cell-surface hydrophobicity, scanning electron microscopy (SEM), and confocal laser scanning microscopy (CLSM). The results demonstrated that the inhibition was related to type of acidulant and pH value. At pH 5.0, the antibacterial effect was more pronounced in the presence of acetic acid (58-60% growth reduction) compared with that in the presence of lactic (7-16% growth reduction) and hydrochloric acids (23-24% reduction). The biofilm biomass of Staphylococcus aureus and Staphylococcus epidermidis was reduced by 92, 85, 63, and 93, 87, 81% after exposition to acetic, lactic, and hydrochloric acids, respectively. Increasing the pH from 5.0 to 6.0 resulted in a noticeable reduction in the effectiveness of acids. A minor cells hydrophobic character was also documented. The SEM and CLSM revealed a poorly structured and thinner biofilm compared with the dense and multilayered control. Acidic environment could have important implications for food-processing system to prevent bacterial colonization and control biofilm formation. The findings of this study lead to consider the rational use of the type of acid to achieve acidic environments.

  4. Intermittent PTH stimulates periosteal bone formation by actions on post-mitotic preosteoblasts.

    PubMed

    Jilka, Robert L; O'Brien, Charles A; Ali, A Afshan; Roberson, Paula K; Weinstein, Robert S; Manolagas, Stavros C

    2009-02-01

    Intermittent administration of parathyroid hormone (PTH) stimulates bone formation on the surface of cancellous and periosteal bone by increasing the number of osteoblasts. Previous studies of ours in mice demonstrated that intermittent PTH increases cancellous osteoblast number at least in part by attenuating osteoblast apoptosis, but the mechanism responsible for the anabolic effect of the hormone on periosteal bone is unknown. We report that daily injections of 100 ng/g of PTH(1-34) to 4-6 month old mice increased the number of osteoblasts on the periosteum of lumbar vertebrae by 2-3 fold as early as after 2 days. However, the prevalence of apoptotic periosteal osteoblasts was only 0.2% in vehicle treated animals, which is approximately 20-fold lower than is the case for cancellous osteoblasts. Moreover, PTH did not have a discernable effect on periosteal osteoblast apoptosis. Administration of BrdU for 4 days failed to label periosteal osteoblasts under either basal conditions or following administration of PTH. Cancellous osteoblasts, on the other hand, were labeled under basal conditions, but PTH did not increase the percentage of BrdU-positive cells. Thus, intermittent PTH does not increase cancellous or periosteal osteoblast number by stimulating the proliferation of osteoblast progenitors. Consistent with high turnover of cancellous osteoblasts as compared to that of periosteal osteoblasts, ganciclovir-induced ablation of replicating osteoblast progenitors in mice expressing thymidine kinase under the control of the 3.6 kb rat Col1A1 promoter resulted in disappearance of osteoblasts from cancellous bone over a 7-14 day period, whereas periosteal osteoblasts were unaffected. However, 14 days of pre-treatment with ganciclovir prevented PTH anabolism on periosteal bone. We conclude that in cancellous bone, attenuation of osteoblast apoptosis by PTH increases osteoblast number because their rate of apoptosis is high, making this effect of the hormone profound

  5. Differential regulation of blood vessel formation between standard and delayed bone healing.

    PubMed

    Lienau, Jasmin; Schmidt-Bleek, Katharina; Peters, Anja; Haschke, Franek; Duda, Georg N; Perka, Carsten; Bail, Hermann J; Schütze, Norbert; Jakob, Franz; Schell, Hanna

    2009-09-01

    Blood vessel formation is a prerequisite for bone healing. In this study, we tested the hypothesis that a delay in bone healing is associated with an altered regulation of blood vessel formation. A tibial osteotomy was performed in two groups of sheep and stabilized with either a rigid external fixator leading to standard healing or with a highly rotationally unstable one leading to delayed healing. At days 4, 7, 9, 11, 14, 21, and 42 after surgery, total RNA was extracted from the callus. Gene expressions of vWF, an endothelial cell marker, and of several molecules related to blood vessel formation were studied by qPCR. Furthermore, histology was performed on fracture hematoma and callus sections. Histologically, the first blood vessels were detected at day 7 in both groups. mRNA expression levels of vWF, Ang1, Ang2, VEGF, CYR61, FGF2, MMP2, and TIMP1 were distinctly lower in the delayed compared to the standard healing group at several time points. Based on differential expression patterns, days 7 and 21 postoperatively were revealed to be essential time points for vascularization of the ovine fracture callus. This work demonstrates for the first time a differential regulation of blood vessel formation between standard and mechanically induced delayed healing in a sheep osteotomy model.

  6. Surface micromorphology of cross-linked tetrafunctional polylactide scaffolds inducing vessel growth and bone formation.

    PubMed

    Kuznetsova, Daria; Ageykin, Aleksey; Koroleva, Anastasia; Deiwick, Andrea; Shpichka, Anastasia; Solovieva, Anna; Kostjuk, Sergey; Meleshina, Aleksandra; Rodimova, Svetlana; Akovanceva, Anastasia; Butnaru, Denis; Frolova, Anastasia; Zagaynova, Elena; Chichkov, Boris; Bagratashvili, Victor; Timashev, Peter

    2017-03-16

    In the presented study, we have developed a synthetic strategy allowing a gradual variation of a polylactide arms' length, which later influences the micromorphology of the scaffold surface, formed by a two-photon polymerization technique. It has been demonstrated that the highest number of cells is present on the scaffolds with the roughest surface made of the polylactide with longer arms (PLA760), and osteogenic differentiation of mesenchymal stem cells is most pronounced on such scaffolds. According to the results of biological testing, the PLA760 scaffolds were implanted into a created cranial defect in a mouse for an in vivo assessment of the bone tissue formation. The in vivo experiments have shown that, by week 10, deposition of calcium phosphate particles occurs in the scaffold at the defect site, as well as, the formation of a new bone and ingrowth of blood vessels from the surrounding tissues. These results demonstrate that the cross-linked microstructured tetrafunctional polylactide scaffolds are promising microstructures for bone regeneration in tissue engineering.

  7. Antheraea pernyi silk sericin mediating biomimetic nucleation and growth of hydroxylapatite crystals promoting bone matrix formation.

    PubMed

    Jiayao, Zhuang; Guanshan, Zhou; Jinchi, Zhang; Yuyin, Chen; Yongqiang, Zhu

    2017-03-01

    Bone biomineralization is well-regulated processes mediated by extracellular matrix proteins. The materials that can direct nucleation of hydroxylapatite (HAp) crystals and assembly of well-structured material-minerals complex are the key to mimicking the natural mineralization. This study used sericin from Antheraea pernyi (A.pernyi), non-mulberry silkworm cocoon as template to mediate nucleation of HAp crystals. Here we find out that AS (Antheraea pernyi sericin) can nucleate the formation HAp crystals in simulated body fluid verified by XRD and FTIR observations. The HAp crystals are organized into nano-rods oriented with c-axis preferentially parallel to the long axis of AS due to hydrogen bonds and electrostatic interaction and finally aggregated into HAp globule. The cell culture of human bone marrow-derived mesenchymal stem cells (BMSCs) showed that the HAp crystals mediated by AS not only stimulate cell adhesion and proliferation but also promote 0f osteogenic differentiation, suggesting that the resultant mineralized AS biomaterial has potential in promoting bone formation. Thus our work will provide significant implication on biomineralization of A. pernyi silk sericin as a potential scaffold for tissue engineering.

  8. Stimulatory effect of menaquinone-7 (vitamin K2) on osteoblastic bone formation in vitro.

    PubMed

    Yamaguchi, M; Sugimoto, E; Hachiya, S

    2001-07-01

    Menaquinone-7, which is vitamin K2 (menatetrenone) with seven isoprene units, is highly contained in the fermented soybean. The effect of menaquinone-7 (MK-7) on osteoblastic bone formation was investigated. Femoral-diaphyseal and metaphyseal tissues of young male rats (4 weeks old) were cultured for 48 h in a medium containing either vehicle or MK-7 (10(-7)-10(-5) M). Calcium content, alkaline phosphatase activity, and deoxyribonuclic acid (DNA) content in the diaphyseal and metaphyseal tissues was significantly increased in the presence of MK-7 (10(-6) and 10(-5) M). The effect of MK-7 in increasing the diaphyseal and metaphyseal calcium content and alkaline phosphatase activity was completely prevented in the presence of cycloheximide (10(-6) M), an inhibitor of protein synthesis. Moreover, osteoblastic MC3T3-E1 cells after subculture were cultured for 24 h in a serum-free medium containing MK-7 (10(-7)-10(-5) M). Protein content, alkaline phophatase activity, osteocalcin and DNA content in the cells was significantly increased in the presence of MK-7 (10(-6) and 10(-5) M). The effect of MK-7 in increasing protein content, alkaline phosphatase activity, and osteocalcin production in the cells was completely blocked by cycloheximide. This study demonstrates that MK-7 has an anabolic effect on bone tissue and osteoblastic MC3T3-E1 cells in vitro, suggesting that the compound can stimulate osteoblastic bone formation.

  9. Altitude, pasture type, and sheep breed affect bone metabolism and serum 25-hydroxyvitamin D in grazing lambs.

    PubMed

    Willems, Helen; Leiber, Florian; Kohler, Martina; Kreuzer, Michael; Liesegang, Annette

    2013-05-15

    This study aimed to investigate the bone development of two mountain sheep breeds during natural summer grazing either in the lowlands or on different characteristic alpine pastures. Pasture types differed in topographic slope, plant species composition, general nutritional feeding value, Ca and P content, and Ca:P ratio of herbage. Twenty-seven Engadine sheep (ES) lambs and 27 Valaisian Black Nose sheep (VS) lambs were divided into four groups of 6 to 7 animals per breed and allocated to three contrasting alpine pasture types and one lowland pasture type. The lambs were slaughtered after 9 wk of experimental grazing. The steep alpine pastures in combination with a high (4.8) to very high (13.6) Ca:P ratio in the forage decreased total bone mineral content as measured in the middle of the left metatarsus of the lambs from both breeds, and cortical bone mineral content and cortical bone mineral density of ES lambs. Breed × pasture type interactions occurred in the development of total and cortical bone mineral content, and in cortical thickness, indicating that bone metabolism of different genotypes obviously profited differently from the varying conditions. An altitude effect occurred for 25-hydroxyvitamin D with notably higher serum concentrations on the three alpine sites, and a breed effect led to higher concentrations for ES than VS. Despite a high variance, there were pasture-type effects on serum markers of bone formation and resorption.

  10. New Bone Formation after Ligation of the External Carotid Artery and Resection of a Large Aneurysmal Bone Cyst of the Mandible with Reconstruction: A Case Report

    PubMed Central

    Perumal, Colin; Mohamed, Ashraf; Singh, Avin

    2011-01-01

    The aneurysmal bone cyst (ABC) is a benign cystic and expanding osteolytic lesion consisting of bone-filled spaces of variable size, separated by connective tissue containing trabeculae of bone or osteoid tissue and osteoclast giant cells. Radiographic findings may vary from unicystic or moth-eaten radiolucencies to extensive multilocular lesions with bilateral expansion and destruction of mandibular cortices. Treatment modalities include curettage (with reported recurrences) and resection with immediate reconstruction. The main arterial and feeder vessels may be embolized to prevent profuse intraoperative blood loss and achieve a bloodless surgical field. Failed embolization may necessitate ligation of the external carotid artery of the affected side. PMID:23450035

  11. Antiosteoporotic Activity of Dioscorea alata L. cv. Phyto through Driving Mesenchymal Stem Cells Differentiation for Bone Formation

    PubMed Central

    Peng, Kang-Yung; Horng, Lin-Yea; Sung, Hui-Ching; Huang, Hui-Chuan; Wu, Rong-Tsun

    2011-01-01

    The aim of this study was to evaluate the effect of an ethanol extract of the rhizomes of Dioscorea alata L. cv. Phyto, Dispo85E, on bone formation and to investigate the mechanisms involved. Our results showed that Dispo85E increased the activity of alkaline phosphatase (ALP) and bone nodule formation in primary bone marrow cultures. In addition, Dispo85E stimulated pluripotent C3H10T1/2 stem cells to differentiate into osteoblasts rather than adipocytes. Our in vivo data indicated that Dispo85E promotes osteoblastogenesis by increasing ALP activity and bone nodule formation in both intact and ovariectomized (OVX) mice. Microcomputed tomography (μCT) analysis also showed that Dispo85E ameliorates the deterioration of trabecular bone mineral density (tBMD), trabecular bone volume/total volume (BV/TV), and trabecular bone number (Tb.N) in OVX mice. Our results suggested that Dispo85E is a botanical drug with a novel mechanism that drives the lineage-specific differentiation of bone marrow stromal cells and is a candidate drug for osteoporosis therapy. PMID:21760825

  12. Effect of estrogen/gestagen and 24R,25-dihydroxyvitamin D3 therapy on bone formation in postmenopausal women

    SciTech Connect

    Thomsen, K.; Riis, B.; Christiansen, C.

    1986-12-01

    The effect of two different estrogen/gestagen regimens and 24R,25-(OH)2-cholecalciferol on bone formation was studied in a randomized trial with 144 healthy postmenopausal women. Urinary excretion (UE) of /sup 99m/technetium-diphosphonate and serum alkaline phosphatase (AP) was determined before and then once a year for 2 years of treatment. Both estimates of bone formation showed highly significant decreases (p less than .001) to normal premenopausal levels in women receiving unopposed 17 beta-estradiol or in a sequential combination with progestagen, whereas unchanged high values were found in the groups receiving 24R,25-(OH)2D3 and placebo. The data show that bone turnover increases in early postmenopausal women concomitantly with the loss of bone mass, and that hormonal substitutional therapy normalizes the total skeletal turnover as well as preventing bone loss.

  13. Osteoclasts on bone and dentin in vitro: mechanism of trail formation and comparison of resorption behavior.

    PubMed

    Rumpler, M; Würger, T; Roschger, P; Zwettler, E; Sturmlechner, I; Altmann, P; Fratzl, P; Rogers, M J; Klaushofer, K

    2013-12-01

    The main function of osteoclasts in vivo is the resorption of bone matrix, leaving behind typical resorption traces consisting of pits and trails. The mechanism of pit formation is well described, but less is known about trail formation. Pit-forming osteoclasts possess round actin rings. In this study we show that trail-forming osteoclasts have crescent-shaped actin rings and provide a model that describes the detailed mechanism. To generate a trail, the actin ring of the resorption organelle attaches with one side outside the existing trail margin. The other side of the ring attaches to the wall inside the trail, thus sealing that narrow part to be resorbed next (3–21 lm). This 3D configuration allows vertical resorption layer-by-layer from the surface to a depth in combination with horizontal cell movement. Thus, trails are not just traces of a horizontal translation of osteoclasts during resorption. Additionally, we compared osteoclastic resorption on bone and dentin since the latter is the most frequently used in vitro model and data are extrapolated to bone. Histomorphometric analyses revealed a material-dependent effect reflected by an 11-fold higher resorption area and a sevenfold higher number of pits per square centimeter on dentin compared to bone. An important material-independent aspect was reflected by comparable mean pit area (μm²) and podosome patterns. Hence, dentin promotes the generation of resorbing osteoclasts, but once resorption has started, it proceeds independently of material properties. Thus, dentin is a suitable model substrate for data acquisition as long as osteoclast generation is not part of the analyses.

  14. Clonal distribution of osteoprogenitor cells in cultured chick periostea: Functional relationship to bone formation

    SciTech Connect

    McCulloch, C.A.; Fair, C.A.; Tenenbaum, H.C.; Limeback, H.; Homareau, R. )

    1990-08-01

    Folded explants of periosteum from embryonic chick calvaria form bone-like tissue when grown in the presence of ascorbic acid, organic phosphate, and dexamethasone. All osteoblast-like cells in these cultures arise de novo by differentiation of osteoprogenitor cells present in the periosteum. To study the spatial and functional relationships between bone formation and osteoprogenitor cells, cultures were continuously labeled with (3H)thymidine for periods of 1-5 days. Radioautographs of serial 2-microns plastic sections stained for alkaline phosphatase (AP) showed maximal labeling of 30% of fibroblastic (AP-negative) cells by 3 days while osteogenic cells (AP-positive) exhibited over 95% labeling by 5 days. No differential shifts in labeling indices, grain count histograms of fibroblastic and osteogenic cells or numbers of AP-positive cells were observed, indicating no significant recruitment of cells from the fibroblastic to the osteogenic compartment. Despite the continuous presence of (3H)thymidine, less than 35% of both osteoblasts and osteocytes were labeled at 5 days, indicating that only one-third of the osteoprogenitor cells had cycled prior to differentiation. Spatial clustering of (3H)thymidine-labeled cells was measured by computer-assisted morphometry and application of the Poisson distribution to assess contagion. Cluster size and number of labeled cells per cluster did not vary between 1-3 days, but the number of clusters increased 20-fold between Day 1 and Day 3. Three-dimensional reconstruction from serial sections showed that clusters formed long, tubular arrays of osteogenic cells up to eight cells in length and located within 2-3 cell layers from the bone surface. Selective killing of S-phase cells with two pulse labels of high specific activity (3H)thymidine at 1 and 2 days of culture completely blocked bone formation.

  15. A nutrient combination that can affect synapse formation.

    PubMed

    Wurtman, Richard J

    2014-04-23

    Brain neurons form synapses throughout the life span. This process is initiated by neuronal depolarization, however the numbers of synapses thus formed depend on brain levels of three key nutrients-uridine, the omega-3 fatty acid DHA, and choline. Given together, these nutrients accelerate formation of synaptic membrane, the major component of synapses. In infants, when synaptogenesis is maximal, relatively large amounts of all three nutrients are provided in bioavailable forms (e.g., uridine in the UMP of mothers' milk and infant formulas). However, in adults the uridine in foods, mostly present at RNA, is not bioavailable, and no food has ever been compelling demonstrated to elevate plasma uridine levels. Moreover, the quantities of DHA and choline in regular foods can be insufficient for raising their blood levels enough to promote optimal synaptogenesis. In Alzheimer's disease (AD) the need for extra quantities of the three nutrients is enhanced, both because their basal plasma levels may be subnormal (reflecting impaired hepatic synthesis), and because especially high brain levels are needed for correcting the disease-related deficiencies in synaptic membrane and synapses.

  16. Cancer Cell Expression of Autotaxin Controls Bone Metastasis Formation in Mouse through Lysophosphatidic Acid-Dependent Activation of Osteoclasts

    PubMed Central

    David, Marion; Wannecq, Estelle; Descotes, Françoise; Jansen, Silvia; Deux, Blandine; Ribeiro, Johnny; Serre, Claire-Marie; Grès, Sandra; Bendriss-Vermare, Nathalie; Bollen, Mathieu; Saez, Simone; Aoki, Junken; Saulnier-Blache, Jean-Sébastien; Clézardin, Philippe; Peyruchaud, Olivier

    2010-01-01

    Background Bone metastases are highly frequent complications of breast cancers. Current bone metastasis treatments using powerful anti-resorbtive agents are only palliative indicating that factors independent of bone resorption control bone metastasis progression. Autotaxin (ATX/NPP2) is a secreted protein with both oncogenic and pro-metastatic properties. Through its lysosphospholipase D (lysoPLD) activity, ATX controls the level of lysophosphatidic acid (LPA) in the blood. Platelet-derived LPA promotes the progression of osteolytic bone metastases of breast cancer cells. We asked whether ATX was involved in the bone metastasis process. We characterized the role of ATX in osteolytic bone metastasis formation by using genetically modified breast cancer cells exploited on different osteolytic bone metastasis mouse models. Methodology/Principal Findings Intravenous injection of human breast cancer MDA-B02 cells with forced expression of ATX (MDA-B02/ATX) to inmmunodeficiency BALB/C nude mice enhanced osteolytic bone metastasis formation, as judged by increased bone loss, tumor burden, and a higher number of active osteoclasts at the metastatic site. Mouse breast cancer 4T1 cells induced the formation of osteolytic bone metastases after intracardiac injection in immunocompetent BALB/C mice. These cells expressed active ATX and silencing ATX expression inhibited the extent of osteolytic bone lesions and decreased the number of active osteoclasts at the bone metastatic site. In vitro, osteoclast differentiation was enhanced in presence of MDA-B02/ATX cell conditioned media or recombinant autotaxin that was blocked by the autotaxin inhibitor vpc8a202. In vitro, addition of LPA to active charcoal-treated serum restored the capacity of the serum to support RANK-L/MCSF-induced osteoclastogenesis. Conclusion/Significance Expression of autotaxin by cancer cells controls osteolytic bone metastasis formation. This work demonstrates a new role for LPA as a factor that stimulates

  17. Behaviour of water bound in bone marrow cells affected by organic solvents of different polarity.

    PubMed

    Turov, Vladimir V; Kerus, Sergey V; Gun'ko, Vladimir M

    2009-08-01

    The behaviour of intracellular water affected by organic solvents of different polarity in partially dehydrated marrow cells obtained from tubular bones of broiler chickens was studied using (1)H NMR spectroscopy at 210-290K. The (1)H NMR spectra of intracellular water include two signals which can be assigned to strongly (SAW, chemical shift of the proton resonance delta(H)=4-5ppm) and weakly (WAW, delta(H)=1.2-1.7ppm) associated waters which can be also divided into weakly (WBW, frozen at 250-0.8kJ/mol) and strongly (SBW, unfrozen at T<250K, DeltaG<-0.8kJ/mol) bound intracellular waters. Solvents of different polarity such as dimethylsulfoxide-d(6) (Me(2)SO-d(6)), acetonitrile-d(3), and chloroform-d differently affect structure, Gibbs free energy, and molecular mobility of intracellular water. A maximal fraction of SBW in WAW and a minimal fraction of SBW in SAW are observed on absorption of acetonitrile (0.8g/g) by cells. The opposite results are on addition of Me(2)SO (0.8g/g) which strongly changes organisation of intracellular water and enhances the freezing point depression of SBW.

  18. TIMESCALES ON WHICH STAR FORMATION AFFECTS THE NEUTRAL INTERSTELLAR MEDIUM

    SciTech Connect

    Stilp, Adrienne M.; Dalcanton, Julianne J.; Weisz, Daniel R.; Williams, Benjamin F.; Warren, Steven R.; Skillman, Evan; Ott, Juergen; Dolphin, Andrew E.

    2013-08-01

    Turbulent neutral hydrogen (H I) line widths are often thought to be driven primarily by star formation (SF), but the timescale for converting SF energy to H I kinetic energy is unclear. As a complication, studies on the connection between H I line widths and SF in external galaxies often use broadband tracers for the SF rate, which must implicitly assume that SF histories (SFHs) have been constant over the timescale of the tracer. In this paper, we compare measures of H I energy to time-resolved SFHs in a number of nearby dwarf galaxies. We find that H I energy surface density is strongly correlated only with SF that occurred 30-40 Myr ago. This timescale corresponds to the approximate lifetime of the lowest mass supernova progenitors ({approx}8 M{sub Sun }). This analysis suggests that the coupling between SF and the neutral interstellar medium is strongest on this timescale, due either to an intrinsic delay between the release of the peak energy from SF or to the coherent effects of many supernova explosions during this interval. At {Sigma}{sub SFR} > 10{sup -3} M{sub Sun} yr{sup -1} kpc{sup -2}, we find a mean coupling efficiency between SF energy and H I energy of {epsilon} = 0.11 {+-} 0.04 using the 30-40 Myr timescale. However, unphysical efficiencies are required in lower {Sigma}{sub SFR} systems, implying that SF is not the primary driver of H I kinematics at {Sigma}{sub SFR} < 10{sup -3} M{sub Sun} yr{sup -1} kpc{sup -2}.

  19. Eldecalcitol improves mechanical strength of cortical bones by stimulating the periosteal bone formation in the senescence-accelerated SAM/P6 mice - a comparison with alfacalcidol.

    PubMed

    Shiraishi, Ayako; Sakai, Sadaoki; Saito, Hitoshi; Takahashi, Fumiaki

    2014-10-01

    Eldecalcitol (ELD), a 2β-hydroxypropyloxy derivative of 1α,25(OH)2D3, is a potent inhibitor of bone resorption that has demonstrated a greater effect at reducing the risk of fracture in osteoporotic patients than alfacalcidol (ALF). In the present study, we used the senescence-accelerated mouse strain P6 (SAM/P6), which has low bone mass caused by osteoblast dysfunction, to evaluate the effect of ELD on cortical bone in comparison with ALF. Four-month-old SAM/P6 mice were given either ELD (0.025 or 0.05μg/kg) or ALF (0.2 or 0.4μg/kg) by oral gavage 5 times/week for 6 weeks. Both ELD and ALF increased serum calcium (Ca) in a dose-dependent manner. Serum Ca levels in the ELD 0.05μg/kg group were comparable to those of the ALF 0.2μg/kg group. ELD 0.05μg/kg significantly improved the bone biomechanical properties of the femur compared with the vehicle control group (p<0.001) and the ALF 0.2μg/kg group (p<0.05) evaluated by 3-point bending test. The cortical area of the mid-femur in the ELD 0.05μg/kg group but not the ALF 0.2μg/kg group was significantly higher than those of the vehicle control group (p<0.001). Bone histomorphometry revealed that in the femoral endocortical surface, the suppression of bone resorption parameters (N.Oc/BS) and bone formation parameters (MS/BS) by ELD (0.05μg/kg) was greater than that by ALF (0.2μg/kg). In contrast, in the femoral periosteal surface, ELD 0.05μg/kg significantly increased bone formation parameters (BFR/BS, MS/BS) compared with the vehicle control group (p<0.05, p<0.01, respectively), whereas ALF 0.2μg/kg did not alter these parameters. These results indicate that ELD improved the biomechanical properties of femoral cortical bone not only by inhibiting endocortical bone resorption but also by stimulating the periosteal bone formation in SAM/P6 mice. This article is part of a Special Issue entitled '16th Vitamin D Workshop'.

  20. Textural and rheological properties of Pacific whiting surimi as affected by nano-scaled fish bone and heating rates.

    PubMed

    Yin, Tao; Park, Jae W

    2015-08-01

    Textural and rheological properties of Pacific whiting (PW) surimi were investigated at various heating rates with the use of nano-scaled fish bone (NFB) and calcium chloride. Addition of NFB and slow heating improved gel strength significantly. Activity of endogenous transglutaminase (ETGase) from PW surimi was markedly induced by both NFB calcium and calcium chloride, showing an optimal temperature at 30°C. Initial storage modulus increased as NFB calcium concentration increased and the same trend was maintained throughout the temperature sweep. Rheograms with temperature sweep at slow heating rate (1°C/min) exhibited two peaks at ∼ 35°C and ∼ 70°C. However, no peak was observed during temperature sweep from 20 to 90°C at fast heating rate (20°C/min). Protein patterns of surimi gels were affected by both heating rate and NFB calcium concentration. Under slow heating, myosin heavy chain intensity decreased with NFB calcium concentration, indicating formation of ε-(γ-glutamyl) lysine cross-links by ETGase and NFB calcium ion.

  1. A novel therapeutic approach with Caviunin-based isoflavonoid that en routes bone marrow cells to bone formation via BMP2/Wnt-β-catenin signaling.

    PubMed

    Kushwaha, P; Khedgikar, V; Gautam, J; Dixit, P; Chillara, R; Verma, A; Thakur, R; Mishra, D P; Singh, D; Maurya, R; Chattopadhyay, N; Mishra, P R; Trivedi, R

    2014-09-18

    Recently, we reported that extract of Dalbergia sissoo made from leaves and pods have antiresorptive and bone-forming effects. The positive skeletal effect attributed because of active molecules present in the extract of Dalbergia sissoo. Caviunin 7-O-[β-D-apiofuranosyl-(1-6)-β-D-glucopyranoside] (CAFG), a novel isoflavonoid show higher percentage present in the extract. Here, we show the osteogenic potential of CAFG as an alternative for anabolic therapy for the treatment of osteoporosis by stimulating bone morphogenetic protein 2 (BMP2) and Wnt/β-catenin mechanism. CAFG supplementation improved trabecular micro-architecture of the long bones, increased biomechanical strength parameters of the vertebra and femur and decreased bone turnover markers better than genistein. Oral administration of CAFG to osteopenic ovariectomized mice increased osteoprogenitor cells in the bone marrow and increased the expression of osteogenic genes in femur and show new bone formation without uterine hyperplasia. CAFG increased mRNA expression of osteoprotegerin in bone and inhibited osteoclast activation by inhibiting the expression of skeletal osteoclastogenic genes. CAFG is also an effective accelerant for chondrogenesis and has stimulatory effect on the repair of cortical bone after drill-hole injury at the tissue, cell and gene level in mouse femur. At cellular levels, CAFG stimulated osteoblast proliferation, survival and differentiation. Signal transduction inhibitors in osteoblast demonstrated involvement of p-38 mitogen-activated protein kinase pathway stimulated by BMP2 to initiate Wnt/β-catenin signaling to reduce phosphorylation of GSK3-β and subsequent nuclear accumulation of β-catenin. Osteogenic effects were abrogated by Dkk1, Wnt-receptor blocker and FH535, inhibitor of TCF-complex by reduction in β-catenin levels. CAFG modulated MSC responsiveness to BMP2, which promoted osteoblast differentiation via Wnt/β-catenin mechanism. CAFG at 1 mg/kg(/)day dose in

  2. Redundancy and Molecular Evolution: The Rapid Induction of Bone Formation by the Mammalian Transforming Growth Factor-β3 Isoform.

    PubMed

    Ripamonti, Ugo; Duarte, Raquel; Parak, Ruqayya; Dickens, Caroline; Dix-Peek, Therese; Klar, Roland M

    2016-01-01

    The soluble osteogenic molecular signals of the transforming growth factor-β (TGF-β) supergene family are the molecular bases of the induction of bone formation and postnatal bone tissue morphogenesis with translation into clinical contexts. The mammalian TGF-β3 isoform, a pleiotropic member of the family, controls a vast array of biological processes including the induction of bone formation. Recombinant hTGF-β3 induces substantial bone formation when implanted with either collagenous bone matrices or coral-derived macroporous bioreactors in the rectus abdominis muscle of the non-human primate Papio ursinus. In marked contrast, the three mammalian TGF-βs do not initiate the induction of bone formation in rodents and lagomorphs. The induction of bone by hTGF-β3/preloaded bioreactors is orchestrated by inducing fibrin-fibronectin rings that structurally organize tissue patterning and morphogenesis within the macroporous spaces. Induced advancing extracellular matrix rings provide the structural anchorage for hyper chromatic cells, interpreted as differentiating osteoblasts re-programmed by hTGF-β3 from invading myoblastic and/or pericytic differentiated cells. Runx2 and Osteocalcin expression are significantly up-regulated correlating to multiple invading cells differentiating into the osteoblastic phenotype. Bioreactors pre-loaded with recombinant human Noggin (hNoggin), a BMPs antagonist, show down-regulation of BMP-2 and other profiled osteogenic proteins' genes resulting in minimal bone formation. Coral-derived macroporous constructs preloaded with binary applications of hTGF-β3 and hNoggin also show down-regulation of BMP-2 with the induction of limited bone formation. The induction of bone formation by hTGF-β3 is via the BMPs pathway and it is thus blocked by hNoggin. Our systematic studies in P. ursinus with translational hTGF-β3 in large cranio-mandibulo-facial defects in humans are now requesting the re-evaluation of "Bone: formation by

  3. Redundancy and Molecular Evolution: The Rapid Induction of Bone Formation by the Mammalian Transforming Growth Factor-β3 Isoform

    PubMed Central

    Ripamonti, Ugo; Duarte, Raquel; Parak, Ruqayya; Dickens, Caroline; Dix-Peek, Therese; Klar, Roland M.

    2016-01-01

    The soluble osteogenic molecular signals of the transforming growth factor-β (TGF-β) supergene family are the molecular bases of the induction of bone formation and postnatal bone tissue morphogenesis with translation into clinical contexts. The mammalian TGF-β3 isoform, a pleiotropic member of the family, controls a vast array of biological processes including the induction of bone formation. Recombinant hTGF-β3 induces substantial bone formation when implanted with either collagenous bone matrices or coral-derived macroporous bioreactors in the rectus abdominis muscle of the non-human primate Papio ursinus. In marked contrast, the three mammalian TGF-βs do not initiate the induction of bone formation in rodents and lagomorphs. The induction of bone by hTGF-β3/preloaded bioreactors is orchestrated by inducing fibrin-fibronectin rings that structurally organize tissue patterning and morphogenesis within the macroporous spaces. Induced advancing extracellular matrix rings provide the structural anchorage for hyper chromatic cells, interpreted as differentiating osteoblasts re-programmed by hTGF-β3 from invading myoblastic and/or pericytic differentiated cells. Runx2 and Osteocalcin expression are significantly up-regulated correlating to multiple invading cells differentiating into the osteoblastic phenotype. Bioreactors pre-loaded with recombinant human Noggin (hNoggin), a BMPs antagonist, show down-regulation of BMP-2 and other profiled osteogenic proteins' genes resulting in minimal bone formation. Coral-derived macroporous constructs preloaded with binary applications of hTGF-β3 and hNoggin also show down-regulation of BMP-2 with the induction of limited bone formation. The induction of bone formation by hTGF-β3 is via the BMPs pathway and it is thus blocked by hNoggin. Our systematic studies in P. ursinus with translational hTGF-β3 in large cranio-mandibulo-facial defects in humans are now requesting the re-evaluation of “Bone: formation by

  4. The effects of 3D bioactive glass scaffolds and BMP-2 on bone formation in rat femoral critical size defects and adjacent bones.

    PubMed

    Liu, Wai-Ching; Robu, Irina S; Patel, Rikin; Leu, Ming C; Velez, Mariano; Chu, Tien-Min Gabriel

    2014-08-01

    Reconstruction of critical size defects in the load-bearing area has long been a challenge in orthopaedics. In the past, we have demonstrated the feasibility of using a biodegradable load-sharing scaffold fabricated from poly(propylene fumarate)/tricalcium phosphate (PPF/TCP) loaded with bone morphogenetic protein-2 (BMP-2) to successfully induce healing in those defects. However, there is limited osteoconduction observed with the PPF/TCP scaffold itself. For this reason, 13-93 bioactive glass scaffolds with local BMP-2 delivery were investigated in this study for inducing segmental defect repairs in a load-bearing region. Furthermore, a recent review on BMP-2 revealed greater risks in radiculitis, ectopic bone formation, osteolysis and poor global outcome in association with the use of BMP-2 for spinal fusion. We also evaluated the potential side effects of locally delivered BMP-2 on the structures of adjacent bones. Therefore, cylindrical 13-93 glass scaffolds were fabricated by indirect selective laser sintering with side holes on the cylinder filled with dicalcium phosphate dehydrate as a BMP-2 carrier. The scaffolds were implanted into critical size defects created in rat femurs with and without 10 μg of BMP-2. The x-ray and micro-CT results showed that a bridging callus was found as soon as three weeks and progressed gradually in the BMP group while minimal bone formation was observed in the control group. Degradation of the scaffolds was noted in both groups. Stiffness, peak load and energy to break of the BMP group were all higher than the control group. There was no statistical difference in bone mineral density, bone area and bone mineral content in the tibiae and contralateral femurs of the control and BMP groups. In conclusion, a 13-93 bioactive glass scaffold with local BMP-2 delivery has been demonstrated for its potential application in treating large bone defects.

  5. Experiment K305: Quantitative analysis of selected bone parameters

    NASA Technical Reports Server (NTRS)

    Wrongski, T. J.; Morey-Holton, E.; Cann, C. E.; Arnaud, C. D.; Baylink, D. J.; Turner, R. T.; Jee, W. S. S.

    1981-01-01

    The skeletal alterations induced by space flight were determined to be a reduced rate of periosteal bone formation in tibial and humeral diaphyses, a decreased trabecular bone volume, and an increased fat content of the bone marrow in the proximal tibial metaphysis. An increased incidence of arrest lines in flight animals suggested that periosteal bone formation may have ceased during space flight. Endosteal bone resorption was not affected markedly.

  6. Natural products for treatment of osteoporosis: The effects and mechanisms on promoting osteoblast-mediated bone formation.

    PubMed

    An, Jing; Yang, Hao; Zhang, Qian; Liu, Cuicui; Zhao, Jingjing; Zhang, Lingling; Chen, Bo

    2016-02-15

    Osteoporosis is a systemic metabolic bone disease characterized by a reduction in bone mass, bone quality, and microarchitectural deterioration. An imbalance in bone remodeling that is caused by more osteoclast-mediated bone resorption than osteoblast-mediated bone formation results in such pathologic bone disorder. Traditional Chinese medicines (TCM) have long been used to prevent and treat osteoporosis and have received extensive attentions and researches at home and abroad, because they have fewer adverse reactions and are more suitable for long-term use compared with chemically synthesized medicines. Here, we put the emphasis on osteoblasts, summarized the detailed research progress on the active compounds derived from TCM with potential anti-osteoporosis effects and their molecular mechanisms on promoting osteoblast-mediated bone formation. It could be concluded that TCM with kidney-tonifying, spleen-tonifying, and stasis-removing effects all have the potential effects on treating osteoporosis. The active ingredients derived from TCM that possess effects on promoting osteoblasts proliferation and differentiation include flavonoids, glycosides, coumarins, terpenoids (sesquiterpenoids, monoterpenoids, diterpenoids), phenolic acids, phenols and others (tetrameric stilbene, anthraquinones, diarylheptanoids). And it was confirmed that the bone formation effect induced by the above natural products was regulated by the expressions of bone specific matrix proteins (ALP, BSP, OCN, OPN, COL I), transcription factor (Runx2, Cbfa1, Osx), signal pathways (MAPK, BMP), local factors (ROS, NO), OPG/RANKL system of osteoblasts and estrogen-like biological activities. All the studies provided theoretical basis for clinical application, as well as new drug research and development on treating osteoporosis.

  7. Differentiation of osteoblast‑like cells and ectopic bone formation induced by bone marrow stem cells transfected with chitosan nanoparticles containing plasmid‑BMP2 sequences.

    PubMed

    Hong, Zhang Qing; Tao, Liu Meng; Bin, Zhang Xiao

    2017-03-01

    The present study investigated the efficiency of the use of chitosan nanoparticles containing plasmid‑bone morphogenetic protein 2 (pBMP2) sequences (CNPBs) to induce the differentiation of bone marrow stem cells (BMSCs) into osteoblast‑like cells that may be able to promote ectopic bone formation. pBMP2s were constructed, and chitosan nanoparticles were incubated with 50, 100 or 200 µg/ml pBMP2. BMSCs were collected from the tibiae and femurs of 6‑week old rats, cultured and treated with the CNPBs or 200 µg/ml pBMP2 as a positive control. Transfection efficiency was confirmed using the green fluorescent protein assay. Histological staining methods, including alkaline phosphatase, Wright's and von Kasso staining, were used to identify features of osteoblast‑like cells differentiated from BMSCs. Expression levels of the markers of osteoblasts, such as alkaline phosphatase, osteoprotegerin, osteocalcin and osteopontin, were determined to verify the differentiation of BMSCs into osteoblast‑like cells. Ectopic bone formation was observed following the integration of polyglycolic acid (PGA) scaffolds with CNPBs and BMSCs, which were implanted into the dorsal muscles of Sprague‑Dawley rats. Exposure to CNPBs led to the transfection of BMSCs with BMP2. The transfected BMSCs possessed the characteristic phenotypes of osteoblasts. The expression levels of alkaline phosphatase, osteoprotegerin, osteocalcin and osteopontin were significantly higher in the transfected cells compared with the control group, particularly the CBP200 group. PGA scaffolds integrated with BMSCs and CNPBs induced ectopic bone formation, as changes in the morphology of cells were observed using histological staining. Therefore, CNPBs may be a promising method of promoting the formation of novel bone tissue.

  8. Bone formation in calvarial defects of Sprague-Dawley rats by transplantation of calcium phosphate glass.

    PubMed

    Moon, Hyun-Ju; Kim, Kyoung-Nam; Kim, Kwang-Mahn; Choi, Seong-Ho; Kim, Chong-Kwan; Kim, Kee-Deog; LeGeros, Racquel Z; Lee, Yong-Keun

    2005-09-01

    The purpose of this study was to investigate the bone-regenerative effect of calcium phosphate glass in vivo. We prepared amorphous calcium phosphate glass powder having a mean particle size of 400 microm in the system CaO-CaF2-P2O5-MgO-ZnO. Calvarial critical-sized defects (8 mm) were created in 60 male Sprague-Dawley rats. The animals were divided into an experimental group and control group of 30 animals each. Each defect was filled with a constant weight of 0.5 g calcium phosphate glass powder mixed with saline. As a control, the defect was left empty. The rats were sacrificed 2, 4, or 8 weeks postsurgery, and the results evaluated using radiodensitometric and histological studies; they were also examined histomorphometrically. When the calcium phosphate glass powders with 400-microm particles were grafted, the defects were nearly completely filled with new-formed bone in a clean healing condition after 8 weeks. It was observed that the prepared calcium phosphate glass enhanced new bone formation in the calvarial defect of Sprague-Dawley rats and could be expected to have potential for use as a hard tissue regeneration material.

  9. MEKK2 mediates an alternative β-catenin pathway that promotes bone formation

    PubMed Central

    Greenblatt, Matthew Blake; Shin, Dong Yeon; Oh, Hwanhee; Lee, Ki-Young; Zhai, Bo; Gygi, Steven P.; Lotinun, Sutada; Baron, Roland; Liu, Dou; Su, Bing; Glimcher, Laurie H.; Shim, Jae-Hyuck

    2016-01-01

    Proper tuning of β-catenin activity in osteoblasts is required for bone homeostasis, because both increased and decreased β-catenin activity have pathologic consequences. In the classical pathway for β-catenin activation, stimulation with WNT ligands suppresses constitutive phosphorylation of β-catenin by glycogen synthase kinase 3β, preventing β-catenin ubiquitination and proteasomal degradation. Here, we have found that mitogen-activated protein kinase kinase kinase 2 (MAP3K2 or MEKK2) mediates an alternative pathway for β-catenin activation in osteoblasts that is distinct from the canonical WNT pathway. FGF2 activates MEKK2 to phosphorylate β-catenin at serine 675, promoting recruitment of the deubiquitinating enzyme, ubiquitin-specific peptidase 15 (USP15). USP15 in turn prevents the basal turnover of β-catenin by inhibiting its ubiquitin-dependent proteasomal degradation, thereby enhancing WNT signaling. Analysis of MEKK2-deficient mice and genetic interaction studies between Mekk2- and β-catenin–null alleles confirm that this pathway is an important physiologic regulator of bone mass in vivo. Thus, an FGF2/MEKK2 pathway mediates an alternative nonclassical pathway for β-catenin activation, and this pathway is a key regulator of bone formation by osteoblasts. PMID:26884171

  10. Cytokines and growth factors which regulate bone cell function

    NASA Astrophysics Data System (ADS)

    Seino, Yoshiki

    Everybody knows that growth factors are most important in making bone. Hormones enhance bone formation from a long distance. Growth factors promote bone formation as an autocrine or paracrine factor in nearby bone. BMP-2 through BMP-8 are in the TGF-β family. BMP makes bone by enchondral ossification. In bone, IGF-II is most abundant, second, TGF-β, and third IGF-I. TGF-β enhances bone formation mainly by intramembranous ossification in vivo. TGF-β affects both cell proliferation and differentiation, however, TGF-β mainly enhances bone formation by intramembranous ossification. Interestingly, TGF-β is increased by estrogen(E 2), androgen, vitamin D, TGF-β and FGF. IGF-I and IGF-II also enhance bone formation. At present it remains unclear why IGF-I is more active in bone formation than IGF-II, although IGF-II is more abundant in bone compared to IGF-I. However, if only type I receptor signal transduction promotes bone formation, the strong activity of IGF-I in bone formation is understandable. GH, PTH and E 2 promotes IGF-I production. Recent data suggest that hormones containing vitamin D or E 2 enhance bone formation through growth factors. Therefore, growth factors are the key to clarifying the mechanism of bone formation.

  11. Silorane resin supports proliferation, differentiation, and mineralization of MLO-A5 bone cells in vitro and bone formation in vivo

    PubMed Central

    Eick, J. David; Barragan-Adjemian, Cielo; Rosser, Jennifer; Melander, Jennifer R.; Dusevich, Vladimir; Weiler, Rachel A.; Miller, Bradley D.; Kilway, Kathleen V.; Dallas, Mark R.; Bi, Lianxing; Nalvarte, Elisabet L.; Bonewald, Lynda F.

    2015-01-01

    Methyl methacrylate used in bone cements has drawbacks of toxicity, high exotherm, and considerable shrinkage. A new resin, based on silorane/oxirane chemistry, has been shown to have little toxicity, low exotherm, and low shrinkage. We hypothesized that silorane-based resins may also be useful as components of bone cements as well as other bone applications and began testing on bone cell function in vitro and in vivo. MLO-A5, late osteoblast cells, were exposed to polymerized silorane (SilMix) resin (and a standard polymerized bisGMA/TEGDMA methacrylate (BT) resin and compared to culture wells without resins as control. A significant cytotoxic effect was observed with the BT resin resulting in no cell growth, whereas in contrast, SilMix resin had no toxic effects on MLO-A5 cell proliferation, differentiation, nor mineralization. The cells cultured with SilMix produced increasing amounts of alkaline phosphatase (1.8-fold) compared to control cultures. Compared to control cultures, an actual enhancement of mineralization was observed in the silorane resin-containing cultures at days 10 and 11 as determined by von Kossa (1.8–2.0 fold increase) and Alizarin red staining (1.8-fold increase). A normal bone calcium/phosphate atomic ratio was observed by elemental analysis along with normal collagen formation. When used in vivo to stabilize osteotomies, no inflammatory response was observed, and the bone continued to heal. In conclusion, the silorane resin, SilMix, was shown to not only be non cytototoxic, but actually supported bone cell function. Therefore, this resin has significant potential for the development of a nontoxic bone cement or bone stabilizer. PMID:22278990

  12. Metformin revisited: Does this regulator of AMP-activated protein kinase secondarily affect bone metabolism and prevent diabetic osteopathy

    PubMed Central

    McCarthy, Antonio Desmond; Cortizo, Ana María; Sedlinsky, Claudia

    2016-01-01

    Patients with long-term type 1 and type 2 diabetes mellitus (DM) can develop skeletal complications or “diabetic osteopathy”. These include osteopenia, osteoporosis and an increased incidence of low-stress fractures. In this context, it is important to evaluate whether current anti-diabetic treatments can secondarily affect bone metabolism. Adenosine monophosphate-activated protein kinase (AMPK) modulates multiple metabolic pathways and acts as a sensor of the cellular energy status; recent evidence suggests a critical role for AMPK in bone homeostasis. In addition, AMPK activation is believed to mediate most clinical effects of the insulin-sensitizer metformin. Over the past decade, several research groups have investigated the effects of metformin on bone, providing a considerable body of pre-clinical (in vitro, ex vivo and in vivo) as well as clinical evidence for an anabolic action of metformin on bone. However, two caveats should be kept in mind when considering metformin treatment for a patient with type 2 DM at risk for diabetic osteopathy. In the first place, metformin should probably not be considered an anti-osteoporotic drug; it is an insulin sensitizer with proven macrovascular benefits that can secondarily improve bone metabolism in the context of DM. Secondly, we are still awaiting the results of randomized placebo-controlled studies in humans that evaluate the effects of metformin on bone metabolism as a primary endpoint. PMID:27022443

  13. The role of 1,25-dihydroxyvitamin D in the inhibition of bone formation induced by skeletal unloading

    NASA Technical Reports Server (NTRS)

    Halloran, B. P.; Bikle, D. D.; Wronski, T. J.; GLOBUS. R.; Levens, M. J.; Morey-Holton, E.

    1983-01-01

    Skeletal unloading results in osteopenia. To examine the involvement of vitamin D in this process, the rear limbs of growing rats were unloaded and alterations in bone calcium and bone histology were related to changes in serum calcium (Ca), inorganic phosphorus (P sub i), 25-hydroxyvitamin D (25-OH-D), 24,25-dihydroxyvitamin D (24,25(OH)2D and 1,25-dihydroxyvitamin D (1,25(OH)2D. Acute skeletal unloading induced a transitory inhibition of Ca accumulation in unloaded bones. This was accompanied by a transitory rise in serum Ca, a 21% decrease in longitudinal bone growth (P 0.01), a 32% decrease in bone surface lined with osteoblasts (P .05), no change in bone surface lined with osteoclasts and a decrease in circulating (1,25(OH)2D. No significant changes in the serum concentrations of P sub i, 25-OH-D or 24,25(OH)2D were observed. After 2 weeks of unloading, bone Ca stabilized at approximately 70% of control and serum Ca and 1,25(OH)2D returned to control values. Maintenance of a constant serum 1,25(OH)2D concentration by chronic infusion of 1,25(OH)2D (Alza osmotic minipump) throughout the study period did not prevent the bone changes induced by acute unloading. These results suggest that acute skeletal unloading in the growing rat produces a transitory inhibition of bone formation which in turn produces a transitory hypercalcemia.

  14. Dietary supplements and physical exercise affecting bone and body composition in frail elderly persons.

    PubMed Central

    de Jong, N; Chin A Paw, M J; de Groot, L C; Hiddink, G J; van Staveren, W A

    2000-01-01

    OBJECTIVES: This study determined the effect of enriched foods and all-around physical exercise on bone and body composition in frail elderly persons. METHODS: A 17-week randomized, controlled intervention trial, following a 2 x 2 factorial design--(1) enriched foods, (2) exercise, (3) both, or (4) neither--was performed in 143 frail elderly persons (aged 78.6 +/- 5.6 years). Foods were enriched with multiple micronutrients; exercises focused on skill training, including strength, endurance, coordination, and flexibility. Main outcome parameters were bone and body composition. RESULTS: Exercise preserved lean mass (mean difference between exercisers and non-exercisers: 0.5 kg +/- 1.2 kg; P < .02). Groups receiving enriched food had slightly increased bone mineral density (+0.4%), bone mass (+0.6%), and bone calcium (+0.6%) compared with groups receiving non-enriched foods, in whom small decreases of 0.1%, 0.2%, and 0.4%, respectively, were found. These groups differed in bone mineral density (0.006 +/- 0.020 g/cm2; P = .08), total bone mass (19 +/- g; P = .04), and bone calcium (8 +/- 21 g; P = .03). CONCLUSIONS: Foods containing a physiologic dose of micronutrients slightly increased bone density, mass, and calcium, whereas moderately intense exercise preserved lean body mass in frail elderly persons. PMID:10846514

  15. Sustained Modeling-Based Bone Formation During Adulthood in Cynomolgus Monkeys May Contribute to Continuous BMD Gains With Denosumab.

    PubMed

    Ominsky, Michael S; Libanati, Cesar; Niu, Qing-Tian; Boyce, Rogely W; Kostenuik, Paul J; Wagman, Rachel B; Baron, Roland; Dempster, David W

    2015-07-01

    Denosumab (DMAb) administration to postmenopausal women with osteoporosis is associated with continued bone mineral density (BMD) increases and low fracture incidence through 8 years, despite persistently reduced bone turnover markers and limited fluorochrome labeling in iliac crest bone biopsies. BMD increases were hypothesized to result from additional accrual of bone matrix via modeling-based bone formation-a hypothesis that was tested by examining fluorochrome labeling patterns in sections from ovariectomized (OVX) cynomolgus monkeys (cynos) treated with DMAb for 16 months. Mature OVX or Sham cynos were treated monthly with vehicle for 16 months, whereas other OVX cynos received monthly 25 or 50 mg/kg DMAb. DMAb groups exhibited very low serum bone resorption and formation biomarkers and near-absent fluorochrome labeling in proximal femur cancellous bone. Despite these reductions, femoral neck dual-energy X-ray absorptiometry (DXA) BMD continued to rise in DMAb-treated cynos, from a 4.6% increase at month 6 to 9.8% above baseline at month 16. Further examination of cortical bone in the proximal femur demonstrated consistent and prominent labeling on the superior endocortex and the inferior periosteal surface, typically containing multiple superimposed labels from month 6 to 16 over smooth cement lines, consistent with continuous modeling-based bone formation. These findings were evident in all groups. Quantitative analysis at another modeling site, the ninth rib, demonstrated that DMAb did not alter the surface extent of modeling-based labels, or the cortical area bound by them, relative to OVX controls, while significantly reducing remodeling-based bone formation and eroded surface. This conservation of modeling-based formation occurred concomitantly with increased femoral neck strength and, when coupled with a reduction in remodeling-based bone loss, is likely to contribute to increases in bone mass with DMAb treatment. Thus, this study provides preclinical

  16. The Autophagic Process Occurs in Human Bone Metastasis and Implicates Molecular Mechanisms Differently Affected by Rab5a in the Early and Late Stages

    PubMed Central

    Maroni, Paola; Bendinelli, Paola; Resnati, Massimo; Matteucci, Emanuela; Milan, Enrico; Desiderio, Maria Alfonsina

    2016-01-01

    Autophagy favours metastatic growth through fuelling energy and nutrients and resistance to anoikis, typical of disseminated-tumour cells. The autophagic process, mediated by a unique organelle, the autophagosome, which fuses with lysosomes, is divided into three steps. Several stages, especially early omegasome formation and isolation-membrane initiation, remain controversial; molecular mechanisms involve the small-GTPase Rab5a, which regulates vesicle traffic for autophagosome formation. We examined Rab5a involvement in the function of key members of ubiquitin-conjugation systems, Atg7 and LC3-lipidated, interacting with the scaffold-protein p62. Immunohistochemistry of Rab5a was performed in human specimens of bone metastasis and pair-matched breast carcinoma; the autophagic-molecular mechanisms affected by Rab5a were evaluated in human 1833 bone metastatic cells, derived from breast-carcinoma MDA-MB231 cells. To clarify the role of Rab5a, 1833 cells were transfected transiently with Rab5a-dominant negative, and/or stably with the short-hairpin RNA Atg7, were exposed to two inhibitors of autolysosome function, and LC3II and p62 expression was measured. We showed basal autophagy in bone-metastatic cells and the pivotal role of Rab5a together with Beclin 1 between the early stages, elongation of isolation membrane/closed autophagosome mediated by Atg7, and the late-degradative stages. This regulatory network might occur in bone-metastasis and in high-grade dysplastic lesions, preceding invasive-breast carcinoma and conferring phenotypic characteristics for dissemination. PMID:27023526

  17. Epigenetic regulation of Tbx18 gene expression during endochondral bone formation.

    PubMed

    Haraguchi, Ryuma; Kitazawa, Riko; Kitazawa, Sohei

    2015-02-01

    Endochondral bone formation is tightly regulated by the spatial and sequential expression of a series of transcription factors. To disclose the roles of TBX18, a member of the T-box transcription factor family, during endochondral bone formation, its spatial and temporal expression patterns were characterized in the limb skeletal region of the developing mouse together with those of established osteochondrogenic markers Sox9, Col2a1, and Runx2. TBX18 expression first appeared in condensed mesenchymal cells (chondro-progenitors) in embryonic-day-10.5 (E10.5) limb bud and was co-localized with Sox9 expression, whereas at E11.5 and E12.5, it became undetectable in mesenchymal cells committed to the chondrocyte lineage. From E13.5 to E18.5, TBX18 expression reappeared in chondrocytes, correlating strongly with Col2a1 expression; furthermore, low level TBX18 expression was found in the Runx2-positive perichondral osteoblastic cell lineage. At the postnatal stage, TBX18 expression was observed in epiphyseal chondrocytes and osteocytes within the lacunae of mature trabecular bone. On the assumption that such characteristic Tbx18 gene expression is epigenetically regulated during mouse limb development, we examined the methylation status of the CpG-island in the mouse Tbx18 gene by methylation-specific polymerase chain reaction. Hypermethylation of the Tbx18 gene promoter became evident at an early embryonic stage in TBX18-negative cells and then disappeared at a late embryonic stage in TBX18-positive cells. Therefore, the temporal suppression of Tbx18 gene expression by the hypermethylation of its promoter seems to trigger the differentiation of mesenchymal cells into hypertrophic chondrocytes in the early stages of endochondral ossification.

  18. Reduction of protein phosphatase 2A Cα enhances bone formation and osteoblast differentiation through the expression of bone-specific transcription factor Osterix.

    PubMed

    Okamura, Hirohiko; Yoshida, Kaya; Ochiai, Kazuhiko; Haneji, Tatsuji

    2011-09-01

    The serine/threonine protein phosphatase 2A (PP2A) participates in regulating many important physiological processes such as control of cell cycle, growth, and division. On the other hand, Osterix is a zinc-finger-containing transcription factor that is essential for the differentiation of osteoblasts and regulation of many bone-related genes. Here we examined the effect of okadaic acid (OA), a specific inhibitor of PP2A, on bone formation in vivo and the molecular mechanism regulated by PP2A Cα in osteoblast differentiation. Administration of 1nM OA to the calvarial region in mice increased bone mineral density, as shown by μCT, while histomorphological analysis showed an increase in mineral apposition and bone thickness in the same region. In addition, treatment with 1nM OA stimulated osteoblast differentiation and the expression of Osterix, bone sialoprotein (Bsp), and osteocalcin (OCN) in mouse osteoblastic MC3T3-E1 cells. Moreover, the expression and phosphatase activity of PP2A Cα was decreased in the initial step of osteoblast differentiation, which was in parallel with an increase in Osterix expression. To further clarify the role of PP2A Cα in osteoblast differentiation, we constructed PP2A knock-down cells by infecting MC3T3-E1 cells with a lentivirus expressing shRNA specific for the PP2A Cα. Accordingly, the silencing of PP2A Cα in MC3T3-E1 cells dramatically increased osteoblast differentiation and mineralization, which were accompanied with expressions of Osterix, Bsp, and OCN. Our data indicate that PP2A Cα plays an important role in the regulation of bone formation and osteoblast differentiation through the bone-related genes.

  19. Using poly(lactic-co-glycolic acid) microspheres to encapsulate plasmid of bone morphogenetic protein 2/polyethylenimine nanoparticles to promote bone formation in vitro and in vivo.

    PubMed

    Qiao, Chunyan; Zhang, Kai; Jin, Han; Miao, Leiying; Shi, Ce; Liu, Xia; Yuan, Anliang; Liu, Jinzhong; Li, Daowei; Zheng, Changyu; Zhang, Guirong; Li, Xiangwei; Yang, Bai; Sun, Hongchen

    2013-01-01

    Repair of large bone defects is a major challenge, requiring sustained stimulation to continually promote bone formation locally. Bone morphogenetic protein 2 (BMP-2) plays an important role in bone development. In an attempt to overcome this difficulty of bone repair, we created a delivery system to slowly release human BMP-2 cDNA plasmid locally, efficiently transfecting local target cells and secreting functional human BMP-2 protein. For transfection, we used polyethylenimine (PEI) to create pBMP-2/PEI nanoparticles, and to ensure slow release we used poly(lactic-co-glycolic acid) (PLGA) to create microsphere encapsulated pBMP-2/PEI nanoparticles, PLGA@pBMP-2/PEI. We demonstrated that pBMP-2/PEI nanoparticles could slowly release from the PLGA@pBMP-2/PEI microspheres for a long period of time. The 3-15 μm diameter of the PLGA@pBMP-2/PEI further supported this slow release ability of the PLGA@pBMP-2/PEI. In vitro transfection assays demonstrated that pBMP-2/PEI released from PLGA@pBMP-2/PEI could efficiently transfect MC3T3-E1 cells, causing MC3T3-E1 cells to secrete human BMP-2 protein, increase calcium deposition and gene expressions of alkaline phosphatase (ALP), runt-related transcription factor 2 (RUNX2), SP7 and I type collagen (COLL I), and finally induce MC3T3-E1 cell differentiation. Importantly, in vivo data from micro-computed tomography (micro-CT) and histological staining demonstrated that the human BMP-2 released from PLGA@pBMP-2/PEI had a long-term effect locally and efficiently promoted bone formation in the bone defect area compared to control animals. All our data suggest that our PLGA-nanoparticle delivery system efficiently and functionally delivers the human BMP-2 cDNA and has potential clinical application in the future after further modification.

  20. Green tea polyphenols improve bone microarchitecture in high-fat-diet-induced obese female rats through suppressing bone formation and erosion.

    PubMed

    Shen, Chwan-Li; Chyu, Ming-Chien; Cao, Jay J; Yeh, James K

    2013-05-01

    This study evaluates the effects of green tea polyphenols (GTPs) on bone microarchitecture in high-fat-diet (HFD)-induced obese female rats. Thirty-six 3-month-old female rats were fed either a control diet or a HFD for 4 months. Animals in the control group continued on the control diet for another 4 months. Animals in the HFD group were divided into two groups, with 0.5 g/100 mL GTP (the HFD+GTP group) or without GTP (the HFD group) in drinking water, in addition to the HFD for another 4 months. Compared to the control group, the HFD group increased bone formation and erosion rates at the tibia, decreased trabecular volume and thickness, but had no impact on bone mineral density (BMD), trabecular number (Tb.N), and separation. Compared to the control group, the HFD+GTP group demonstrates a greater Tb.N at the proximal tibia, and a greater trabecular thickness at the femur and the lumbar vertebrae, but a smaller trabecular separation (Tb.Sp) and mineralizing surface at the proximal tibia, and a reduced endocortical mineral apposition rate (MAR) at the tibia shaft. Relative to the HFD group, the HFD+GTP group demonstrates (1) a higher BMD at the femur, a greater trabecular volume, thickness, and number at the proximal tibia, a larger cortical area and thickness at the tibial shaft, and a greater trabecular volume and thickness at the femur and the lumbar vertebrae, (2) a smaller Tb.Sp, MAR, bone formation rate, and eroded surface at the tibia. We concluded that GTP supplementation in drinking water improves bone microarchitecture in the HFD-induced obese female rats, possibly through suppressing bone turnover, resulting in a larger net bone volume.

  1. Biofilm formation and antibiotic resistance in Salmonella Typhimurium are affected by different ribonucleases.

    PubMed

    Saramago, Margarida; Domingues, Susana; Viegas, Sandra Cristina; Arraiano, Cecília Maria

    2014-01-01

    Biofilm formation and antibiotic resistance are important determinants for bacterial pathogenicity. Ribonucleases control RNA degradation and there is increasing evidence that they have an important role in virulence mechanisms. In this report, we show that ribonucleases affect susceptibility against ribosome-targeting antibiotics and biofilm formation in Salmonella.

  2. In Vitro Biocompability/Osteogenesis and In Vivo Bone Formation Evalution of Peptide-Decorated Apatite Nanocomposites Assisted via Polydopamine.

    PubMed

    Deng, Yi; Sun, Yuhua; Bai, Yanjie; Gao, Xiang; Zhang, Huan; Xu, Anxiu; Huang, Enyi; Deng, Feng; Wei, Shicheng

    2016-04-01

    Enhancing the biocompatibility and osteogenic activity of nano-apatite for applications in bone graft substitutes and bone tissue engineering have been the current challenge in regeneration of lost bone. Inspired by mussels, here we have developed facile biomimetic approaches for preparation of two types of peptide-conjugated apatite nanocompsoties assisted by polydopamine (pDA). We exploited polydopamine chemistry for the modification of nano-apatite crystals: polydopamine coated apatite (HA-c-pDA) and polydopamine template-mediated apatite (HA-t-pDA), on which bone forming peptide was subsequently immobilized under weakly basic conditions to obtain peptide-conjugated apatite nanocomposites (HA-c-pep and HA-t-pep, respectively). TEM images revealed that HA-c-pDA displayed typically rod-like morphology, while HA-t-pDA was sponge-like structure where pDA sheets were decorated by needle-like apatite crystals with low degree of crystallinity. In the cell culture experiments, HA-t-pep nanocomposite exhibited higher cell proliferation, spreading, and alkaline phosphatase activity as well as calcium nodule-formation, compared with pristine nano-HA and HA-c-pep nanocomposite. We then implanted the peptide-decorated apatite into rabbit calvarial defects and analyzed bone formation after 2 months. The data revealed that HA-t-pep group exhibited remarkably enhanced bioactivity and bone formation in vivo. Based on these results, our biomimetic approach could be a promising tool to develop peptide-conjugated apatites for bone regeneration. Meanwhile, the excellent biocompatibility and high osteogenesis of the peptide-conjugated apatite nanocomposite might confer its great potentials in bone repair, bone augmentation, as well as coating of biomedical implants.

  3. A novel method for lateral callus distraction and its importance for the mechano-biology of bone formation.

    PubMed

    Claes, L; Veeser, A; Göckelmann, M; Horvath, D; Dürselen, L; Ignatius, A

    2010-10-01

    We introduce a novel method of lateral callus distraction for bone formation, which avoids the conventional splitting and weakening of bones. At the medial aspect of the sheep tibia the periosteum was resected and small holes were drilled into the cortex to connect the bone surface with the marrow. A distraction device with a hydroxyapatite-coated titanium plate was fixed over the drilled area. After 10 days latency the plate was distracted perpendicular to the bone's long axis twice a day by 0.27 mm for 10 days. The newly formed tissue was then allowed 50 days of maturation. In a control group the plate was fixed 5.4mm distant from the bone surface. After 70 days all sheep were sacrificed and investigated histo-morphologically and with pQCT. Significantly more bone had developed between the lateral bone surface and the plate in the distraction group compared to the control group. There was exclusively intra-membranous bone formation with trabeculae oriented in the direction of the applied distraction. The main calcification occurred weeks after the last distraction. In conventional callus distraction the tissue strain caused by distraction is superimposed by the tissue deformation due to the deformation of the fixation device. In contrast, in the newly introduced lateral callus distraction method pure uniaxial strain occurs. From a mechano-biological point of view these results suggest that pure uniaxial strain induces exclusively intra-membranous bone formation. Furthermore, it shows that the anabolic effect of tissue strain is present even 50 days after the last stimulation by distraction.

  4. The remodeling pattern of human mandibular alveolar bone during prenatal formation from 19 to 270mm CRL.

    PubMed

    Radlanski, Ralf J; Renz, Herbert; Tsengelsaikhan, Nyamdorj; Schuster, Felix; Zimmermann, Camilla A

    2016-05-01

    The underlying mechanisms of human bone morphogenesis leading to a topologically specific shape remain unknown, despite increasing knowledge of the basic molecular aspects of bone formation and its regulation. The formation of the alveolar bone, which houses the dental primordia, and later the dental roots, may serve as a model to approach general questions of bone formation. Twenty-five heads of human embryos and fetuses (Radlanski-Collection, Berlin) ranging from 19mm to 270mm (crown-rump-length) CRL were prepared as histological serial sections. For each stage, virtual 3D-reconstructions were made in order to study the morphogenesis of the mandibular molar primordia with their surrounding bone. Special focus was given to recording the bone-remodeling pattern, as diagnosed from the histological sections. In early stages (19-31mm CRL) developing bone was characterized by appositional only. At 41, in the canine region, mm CRL bony extensions were found forming on the bottom of the trough. Besides general apposition, regions with resting surfaces were also found. At a fetal size of 53mm CRL, septa have developed and led to a compartment for canine development. Furthermore, one shared compartment for the incisor primordia and another shared compartment for the molars also developed. Moreover, the inner surfaces of the dental crypts showed resorption of bone. From this stage on, a general pattern became established such that the compartmentalizing ridges and septa between all of the dental primordia and the brims of the crypts were noted, and were due to appositional growth of bone, while the crypts enlarged on their inner surfaces by resorption. By 160mm CRL, the dental primordia were larger, and all of the bony septa had become reduced in size. The primordia for the permanent teeth became visible at 225mm CRL and shared the crypts of their corresponding deciduous primordia.

  5. Efficacy of a small cell-binding peptide coated hydroxyapatite substitute on bone formation and implant fixation in sheep.

    PubMed

    Ding, Ming; Andreasen, Christina M; Dencker, Mads L; Jensen, Anders E; Theilgaard, Naseem; Overgaard, Søren

    2015-04-01

    Cylindrical critical size defects were created at the distal femoral condyles bilaterally of eight female adult sheep. Titanium implants with 2-mm concentric gaps were inserted and the gaps were filled with one of the four materials: allograft; a synthetic 15-amino acid cell-binding peptide coated hydroxyapatite (ABM/P-15); hydroxyapatite + βtricalciumphosphate+ Poly-Lactic-Acid (HA/βTCP-PDLLA); or ABM/P-15+HA/βTCP-PDLLA. After nine weeks, bone-implant blocks were harvested and sectioned for micro-CT scanning, push-out test, and histomorphometry. Significant bone formation and implant fixation could be observed in all four groups. Interestingly, the microarchitecture of the ABM/P-15 group was significantly different from the control group. Tissue volume fraction and thickness were significantly greater in the ABM/P-15 group than in the allograft group. Bone formation and bone ingrowth to porous titanium implant were not significantly different among the four groups. The ABM/P-15 group had similar shear mechanical properties on implant fixation as the allograft group. Adding HA/βTCP-PDLLA to ABM/P-15 did not significantly change these parameters. This study revealed that ABM/P-15 had significantly bone formation in concentric gap, and its enhancements on bone formation and implant fixation were at least as good as allograft. It is suggested that ABM/P-15 might be a good alternative biomaterial for bone implant fixation in this well-validated critical-size defect gap model in sheep. Nevertheless, future clinical researches should focus on prospective, randomized, controlled trials in order to fully elucidate whether ABM/P-15 could be a feasible candidate for bone substitute material in orthopedic practices.

  6. Senescence: novel insight into DLX3 mutations leading to enhanced bone formation in Tricho-Dento-Osseous syndrome

    PubMed Central

    Zhao, Na; Han, Dong; Liu, Haochen; Li, Yue; Wong, Sing-Wai; Cao, Zhengyi; Xu, Jian; Zhang, Xiaowei; Cai, Tao; Wang, Yixiang; Feng, Hailan

    2016-01-01

    The homeodomain transcription factor distal-less homeobox 3 gene (DLX3) is required for hair, tooth and skeletal development. DLX3 mutations have been found to be responsible for Tricho-Dento-Osseous (TDO) syndrome, characterized by kinky hair, thin-pitted enamel and increased bone density. Here we show that the DLX3 mutation (c.533 A>G; Q178R) attenuates osteogenic potential and senescence of bone mesenchymal stem cells (BMSCs) isolated from a TDO patient, providing a molecular explanation for abnormal increased bone density. Both DLX3 mutations (c.533 A>G and c.571_574delGGGG) delayed cellular senescence when they were introduced into pre-osteoblastic cells MC3T3-E1. Furthermore, the attenuated skeletal aging and bone loss in DLX3 (Q178R) transgenic mice not only reconfirmed that DLX3 mutation (Q178R) delayed cellular senescence, but also prevented aging-mediated bone loss. Taken together, these results indicate that DLX3 mutations act as a loss of function in senescence. The delayed senescence of BMSCs leads to increased bone formation by compensating decreased osteogenic potentials with more generations and extended functional lifespan. Our findings in the rare human genetic disease unravel a novel mechanism of DLX3 involving the senescence regulation of bone formation. PMID:27924851

  7. Impaired bone formation in male idiopathic osteoporosis: further reduction in the presence of concomitant hypercalciuria

    NASA Technical Reports Server (NTRS)

    Zerwekh, J. E.; Sakhaee, K.; Breslau, N. A.; Gottschalk, F.; Pak, C. Y.

    1992-01-01

    We present iliac bone histomorphometric data and related biochemical data from 16 nonalcoholic men (50 +/- 11 (SD) years) referred for evaluation of spontaneous skeletal and/or appendicular fractures and reduced spinal bone density. All men were eugonadal and had no known underlying disorder associated with osteopenia. For the group, mean serum chemistry values were within normal limits including immunoreactive parathyroid hormone, osteocalcin and serum 1,25-dihydroxyvitamin D [1,25(OH)2D]. Nine men demonstrated hypercalciuria (greater than or equal to 0.1 mmol/kg per day) while on a constant metabolic diet of 20 mmol/day Ca. Their 24-hour urinary calcium was significantly greater than that for the remaining 7 men (7.4 +/- 1.6 vs. 5.0 +/- 0.8 mmol/day, p = 0.003), as was their calciuric response to a 1 g oral calcium load (0.23 +/- 0.06 vs. 0.15 +/- 0.05 Ca/creatinine, p = 0.042). Serum parameters (including parathyroid hormone and 1,25(OH)2D) of hypercalciuric and normocalciuric men were not significantly different. Histomorphometric indices for cancellous bone demonstrated significant differences between the entire group of osteoporotic men and age-adjusted normal values for bone volume (11.4 +/- 4.0% vs. 23.2 +/- 4.4%), osteoid surface (5.6 +/- 3.9% vs. 12.1 +/- 4.6%), osteoblastic surface (2.0 +/- 2.3% vs. 3.9 +/- 1.9%), and mineralizing surface (1.9 +/- 2.4% vs. 5.1 +/- 2.7%); there were also significant differences in bone formation rate (total surface referent) (0.004 +/- 0.001 vs. 0.011 +/- 0.006 mm3/mm2 per year). Compared with the normocalciuric group the 9 hypercalciuric men had significantly lower osteoblastic surfaces (1.6 +/- 1.9% vs. 2.5 +/- 2.6%) and mineralizing surfaces (1.4 +/- 1.5% vs. 2.7 +/- 3.2%).(ABSTRACT TRUNCATED AT 250 WORDS).

  8. Paget's Disease of Bone

    MedlinePlus

    ... page please turn Javascript on. Paget's Disease of Bone What is Paget's Disease of Bone? Click for more information Enlarged and Misshapen Bones Paget's disease of bone causes affected bones to ...

  9. Semen astragali complanati- and rhizoma cibotii-enhanced bone formation in osteoporosis rats

    PubMed Central

    2013-01-01

    Background Growing evidence shows that herb medicines have some anti-osteoporotic effects, the mechanism underlying is unknown. This study aims to investigate the therapeutic effect of Chinese herb supplements on rats that had osteoporosis-like symptom induced by ovariectomy (OVX). Methods OVX or sham operations were performed on virgin Wistar rats at three-month old, which were randomly divided into eight groups: sham (sham); OVX control group (OVX); OVX rats with treatments [either diethylstilbestrol (DES) or Semen Astragali Complanati decoction (SACD) or Rhizoma Cibotii decoction (RCD) or Herba Cistanches decoction (HCD) or Semen Allii Tuberosi decoction (SATD)]. Non-surgical rats were served as a normal control (NC). The treatments began 4 weeks after surgery, and lasted for 12 weeks. Bone mass and its turnover were analyzed by histomorphometry. Levels of protein and mRNA of osteoprotegerin (OPG) and receptor activator of nuclear factor κB ligand (RANKL) in osteoblasts (OB) and bone marrow stromal cells (bMSC) were evaluated by immunohistochemistry and in situ hybridization. Results Compared to OVX control, TBV% in both SACD and RCD groups was increased significantly, while TRS%, TFS%, MAR, and mAR were decreased remarkably in the SACD group, only TRS% decreased dramatically in the RCD group. No significant changes in bone formation were observed in either HCD or SATD groups. OPG levels in both protein and mRNA were reduced consistantly in OB and bMSC from OVX control rats, in contrast, RANKL levels in both protein and mRNA were increased significantly. These effects were substantially reversed by treatments with either DES or SACD or RCD. No significant changes in both OPG and RANKL expression were observed in OB and bMSC from OVX rats treated with SATD and HCD. Conclusions Our study showed that SACD and RCD increased bone formation by stimulating OPG expression and downregulating RANKL expression in OB and bMSC. This suggests that SACD and RCD may be

  10. Extracorporeal shock waves alone or combined with raloxifene promote bone formation and suppress resorption in ovariectomized rats

    PubMed Central

    Corrado, Bruno; Pirozzi, Claudio; Paciello, Orlando; Pagano, Teresa Bruna; Russo, Sergio; Calignano, Antonio; Mattace Raso, Giuseppina; Meli, Rosaria

    2017-01-01

    Osteoporosis is a metabolic skeletal disease characterized by an imbalance between osteoclast-mediated bone resorption and osteoblast-mediated bone formation. We examined the beneficial effect of shock waves (SW) alone or in combination with raloxifene (RAL) on bone loss in ovariectomized rats (OVX). Sixteen weeks after surgery, OVX were treated for five weeks with SW at the antero-lateral side of the right hind leg, one session weekly, at 3 Hz (EFD of 0.33 mJ/mm2), or with RAL (5 mg/kg/die, per os) or with SW+RAL. Sera, femurs, tibiae and vertebrae were sampled for following biochemical and histological analysis. SW, alone or combined with RAL, prevented femur weight reduction and the deterioration of trabecular microarchitecture both in femur and vertebrae. All treatments increased Speed of Sound (SoS) values, improving bone mineral density, altered by OVX. Serum parameters involved in bone remodeling (alkaline phosphatase, receptor activator of nuclear factor kappa-B ligand, osteoprotegerin) and osteoblast proliferation (PTH), altered by ovariectomy, were restored by SW and RAL alone or in combination. In tibiae, SW+RAL significantly reduced cathepsin k and TNF-α levels, indicating the inhibition of osteoclast activity, while all treatments significantly increased runt-related transcription factor 2 and bone morphogenetic-2 expression, suggesting an increase in osteoblastogenic activity. Finally, in bone marrow from tibiae, SW or RAL reduced PPARγ and adiponectin transcription, indicating a shift of mesenchymal cells toward osteoblastogenesis, without showing a synergistic effect. Our data indicate SW therapy, alone and in combination with raloxifene, as an innovative strategy to limit the hypoestrogenic bone loss, restoring the balance between bone formation and resorption. PMID:28158228

  11. OPG-Fc treatment in growing pigs leads to rapid reductions in bone resorption markers, serum calcium, and bone formation markers.

    PubMed

    Sipos, W; Zysset, P; Kostenuik, P; Mayrhofer, E; Bogdan, C; Rauner, M; Stolina, M; Dwyer, D; Sommerfeld-Stur, I; Pendl, G; Resch, H; Dall'Ara, E; Varga, P; Pietschmann, P

    2011-12-01

    Inhibition of the receptor activator of NF-κB ligand (RANKL) is a novel therapeutic option in the treatment of osteoporosis and related diseases. The aim of this study was to evaluate bone metabolism and structure in pigs after RANKL inhibition. 12 growing pigs were assigned to 2 groups with 6 animals each. The OPG group received recombinant human OPG-Fc (5 mg/kg IV) at day 0, the control group was given 0.9% NaCl solution. Serum levels of OPG-Fc, calcium (Ca), phosphorus (P), and bone turnover markers were evaluated every 5 days, and pigs were euthanized on day 20. Serum OPG-Fc concentration peaked at day 5 and coincided with significantly decreased Ca, P, and bone turnover markers. By day 15, measureable OPG-Fc serum levels could only be detected in 2/6 animals. With OPG-Fc clearance starting at day 10, serum Ca and P concentrations were not different between the 2 groups. TRACP5b, P1CP, and BAP levels significantly decreased by 40-70% relative to vehicle controls in the OPG-Fc group between days 5 and 10, indicating that pharmacologic concentration of OPG-Fc led to systemic concomitant inhibition of bone formation and resorption in young growing pigs. Dual X-ray absorptiometry data derived from the proximal femur did not differ between the 2 groups. μCT analysis of selected bone sites demonstrated an OPG-Fc-induced improvement of specific bone architectural indices and bone mineralization.

  12. Inhibition of BMP2-induced bone formation by the p65 subunit of NF-κB via an interaction with Smad4.

    PubMed

    Hirata-Tsuchiya, Shizu; Fukushima, Hidefumi; Katagiri, Takenobu; Ohte, Satoshi; Shin, Masashi; Nagano, Kenichi; Aoki, Kazuhiro; Morotomi, Takahiko; Sugiyama, Goro; Nakatomi, Chihiro; Kokabu, Shoichiro; Doi, Takahiro; Takeuchi, Hiroshi; Ohya, Keiichi; Terashita, Masamichi; Hirata, Masato; Kitamura, Chiaki; Jimi, Eijiro

    2014-09-01

    Bone morphogenic proteins (BMPs) stimulate bone formation in vivo and osteoblast differentiation in vitro via a Smad signaling pathway. Recent findings revealed that the activation of nuclear factor-κB (NF-κB) inhibits BMP-induced osteoblast differentiation. Here, we show that NF-κB inhibits BMP signaling by directly targeting the Smad pathway. A selective inhibitor of the classic NF-κB pathway, BAY11-770682, enhanced BMP2-induced ectopic bone formation in vivo. In mouse embryonic fibroblasts (MEFs) prepared from mice deficient in p65, the main subunit of NF-κB, BMP2, induced osteoblastic differentiation via the Smad complex to a greater extent than that in wild-type MEFs. In p65(-/-) MEFs, the BMP2-activated Smad complex bound much more stably to the target element than that in wild-type MEFs without affecting the phosphorylation levels of Smad1/5/8. Overexpression of p65 inhibited BMP2 activity by decreasing the DNA binding of the Smad complex. The C-terminal region, including the TA2 domain, of p65 was essential for inhibiting the BMP-Smad pathway. The C-terminal TA2 domain of p65 associated with the MH1 domain of Smad4 but not Smad1. Taken together, our results suggest that p65 inhibits BMP signaling by blocking the DNA binding of the Smad complex via an interaction with Smad4. Our study also suggests that targeting the association between p65 and Smad4 may help to promote bone regeneration in the treatment of bone diseases.

  13. Spectroscopic investigation on formation and growth of mineralized nanohydroxyapatite for bone tissue engineering applications

    NASA Astrophysics Data System (ADS)

    Gopi, D.; Nithiya, S.; Shinyjoy, E.; Kavitha, L.

    Synthetic calcium hydroxyapatite (HAP,Ca10(PO4)6(OH)2) is a well-known bioceramic material used in orthopaedic and dental applications because of its excellent biocompatibility and bone-bonding ability. Substitution of trace elements, such as Sr, Mg and Zn ions into the structure of calcium phosphates is the subject of widespread investigation. In this paper, we have reported the synthesis of Sr, Mg and Zn co-substituted nanohydroxyapatite by soft solution freezing method. The effect of pH on the morphology of bioceramic nanomaterial was also discussed. The in vitro bioactivity of the as-synthesized bioceramic nanomaterial was determined by soaking it in SBF for various days. The as-synthesized bioceramic nanomaterial was characterized by Fourier transform infrared spectroscopy, X- ray diffraction analysis, Scanning electron microscopy and Energy dispersive X-ray analysis and Transmission electron microscopic techniques respectively. The results obtained in our study have revealed that pH 10 was identified to induce the formation of mineralized nanohydroxyapatite. It is observed that the synthesis of bioceramic nanomaterial not only support the growth of apatite layer on its surface but also accelerate the growth which is evident from the in vitro studies. Therefore, mineralized nanohydroxyapatite is a potential candidate in bone tissue engineering.

  14. The Role of Affect in Attitude Formation toward New Technologies: The Case of Stratospheric Aerosol Injection.

    PubMed

    Merk, Christine; Pönitzsch, Gert

    2017-02-28

    This article analyzes determinants of technology acceptance and their interdependence. It highlights the role of affect in attitude formation toward new technologies and examines how it mediates the influence of stable psychological variables on the technology's acceptability. Based on theory and previous empirical evidence, we develop an analytical framework of attitude formation. We test this framework using survey data on attitudes toward stratospheric aerosol injection (SAI), a technology that could be used to counteract global warming. We show that affect is more important than risk and benefit perception in forming judgment about SAI. Negative and positive affect directly alter the perception of risks and benefits of SAI and its acceptability. Furthermore, affect is an important mediator between stable psychological variables-such as trust in governmental institutions, values, and attitudes-and acceptability. A person's affective response is thus guided by her general attitudes and values.

  15. A magnesium based phosphate binder reduces vascular calcification without affecting bone in chronic renal failure rats.

    PubMed

    Neven, Ellen; De Schutter, Tineke M; Dams, Geert; Gundlach, Kristina; Steppan, Sonja; Büchel, Janine; Passlick-Deetjen, Jutta; D'Haese, Patrick C; Behets, Geert J

    2014-01-01

    The alternative phosphate binder calcium acetate/magnesium carbonate (CaMg) effectively reduces hyperphosphatemia, the most important inducer of vascular calcification, in chronic renal failure (CRF). In this study, the effect of low dose CaMg on vascular calcification and possible effects of CaMg on bone turnover, a persistent clinical controversy, were evaluated in chronic renal failure rats. Adenine-induced CRF rats were treated daily with 185 mg/kg CaMg or vehicle for 5 weeks. The aortic calcium content and area% calcification were measured to evaluate the effect of CaMg. To study the effect of CaMg on bone remodeling, rats underwent 5/6th nephrectomy combined with either a normal phosphorus diet or a high phosphorus diet to differentiate between possible bone effects resulting from either CaMg-induced phosphate deficiency or a direct effect of Mg. Vehicle or CaMg was administered at doses of 185 and 375 mg/kg/day for 8 weeks. Bone histomorphometry was performed. Aortic calcium content was significantly reduced by 185 mg/kg/day CaMg. CaMg ameliorated features of hyperparathyroid bone disease. In CRF rats on a normal phosphorus diet, the highest CaMg dose caused an increase in osteoid area due to phosphate depletion. The high phosphorus diet combined with the highest CaMg dose prevented the phosphate depletion and thus the rise in osteoid area. CaMg had no effect on osteoblast/osteoclast or dynamic bone parameters, and did not alter bone Mg levels. CaMg at doses that reduce vascular calcification did not show any harmful effect on bone turnover.

  16. The synergistic induction of bone formation by the osteogenic proteins of the TGF-β supergene family.

    PubMed

    Ripamonti, Ugo; Parak, Ruqayya; Klar, Roland M; Dickens, Caroline; Dix-Peek, Thérèse; Duarte, Raquel

    2016-10-01

    The momentum to compose this Leading Opinion on the synergistic induction of bone formation suddenly arose when a simple question was formulated during a discussion session on how to boost the often limited induction of bone formation seen in clinical contexts. Re-examination of morphological and molecular data available on the rapid induction of bone formation by the recombinant human transforming growth factor-β3 (hTGF-β3) shows that hTGF-β3 replicates the synergistic induction of bone formation as invocated by binary applications of hOP-1:hTGF-β1 at 20:1 by weight when implanted in heterotopic sites of the rectus abdominis muscle of the Chacma baboon, Papio ursinus. The rapid induction of bone formation in primates by hTGF-β3 may stem from bursts of cladistic evolution, now redundant in lower animal species but still activated in primates by relatively high doses of hTGF-β3. Contrary to rodents, lagomorphs and canines, the three mammalian TGF-β isoforms induce rapid and substantial bone formation when implanted in heterotopic rectus abdominis muscle sites of P. ursinus, with unprecedented regeneration of full thickness mandibular defects with rapid mineralization and corticalization. Provocatively, thus providing potential molecular and biological rationales for the apparent redundancy of osteogenic molecular signals in primates, binary applications of recombinant human osteogenic protein-1 (hOP-1) with low doses of hTGF-β1 and -β3, synergize to induce massive ossicles in heterotopic rectus abdominis, orthotopic calvarial and mandibular sites of P. ursinus. The synergistic binary application of homologous but molecularly different soluble molecular signals has indicated that per force several secreted molecular signals are required singly, synchronously and synergistically to induce optimal osteogenesis. The morphological hallmark of the synergistic induction of bone formation is the rapid differentiation of large osteoid seams enveloping

  17. Bone formation within the vicinity of biodegradable magnesium alloy implant in a rat femur model

    NASA Astrophysics Data System (ADS)

    Han, Hyung-Seop; Kim, Young-Yul; Kim, Yu-Chan; Cho, Sung-Youn; Cha, Pil-Ryung; Seok, Hyun-Kwang; Yang, Seok-Jo

    2012-04-01

    The purposes of this preliminary study were to investigate the effect of increased Ca contents (5-10 wt% Ca) in Mg-Ca alloy on the mechanical properties and osseous healing rate in a standard rat defect model. Mechanical tests were performed using a compression system followed by qualitative histological analysis using the hemotoxylin and eosin (H&E) staining method and quantitative reverse transcriptase polymerase chain reaction (reverse transcriptase PCR). Mg-Ca alloy degraded fast in vivo while displaying a high level of the bone formation markersOC and ALP. Favorablemechanical strength properties were displayed as Ca content increased from 5 wt% to 10 wt% to show its potential to be considered as a load bearing implant material. The resultfrom this study suggests that the developed Mg-Ca alloy has the potential to serve as a biocompatible load bearing implant material that is degradable and possibly osteoconductive.

  18. Intermittent parathyroid hormone administration counteracts the adverse effects of glucocorticoids on osteoblast and osteocyte viability, bone formation, and strength in mice.

    PubMed

    Weinstein, Robert S; Jilka, Robert L; Almeida, Maria; Roberson, Paula K; Manolagas, Stavros C

    2010-06-01

    Glucocorticoids act directly on bone cells to decrease production of osteoblasts and osteoclasts, increase osteoblast and osteocyte apoptosis, and prolong osteoclast life span. Conversely, daily injections of PTH decrease osteoblast and osteocyte apoptosis and increase bone formation and strength. Using a mouse model, we investigated whether the recently demonstrated efficacy of PTH in glucocorticoid-induced bone disease results from the ability of this therapeutic modality to counteract at least some of the direct effects of glucocorticoids on bone cells. Glucocorticoid administration to 5- to 6-month-old Swiss-Webster mice for 28 d increased the prevalence of osteoblast and osteocyte apoptosis and decreased osteoblast number, activation frequency, and bone formation rate, resulting in reduced osteoid, wall and trabecular width, bone mineral density, and bone strength. In contrast, daily injections of PTH caused a decrease in osteoblast and osteocyte apoptosis and an increase in osteoblast number, activation frequency, bone formation rate, bone mineral density, and bone strength. The decreased osteocyte apoptosis was associated with increased bone strength. When the two agents were combined, all the adverse effects of glucocorticoid excess on bone were prevented. Likewise, in cultured osteoblastic cells, PTH attenuated the adverse effects of glucocorticoids on osteoblast survival and Wnt signaling via an Akt phosphorylation-dependent mechanism. We conclude that intermittent PTH administration directly counteracts the key pathogenetic mechanisms of glucocorticoid excess on bone, thus providing a mechanistic explanation of its efficacy against glucocorticoid-induced osteoporosis.

  19. Staphylococcal biofilm formation on the surface of three different calcium phosphate bone grafts: a qualitative and quantitative in vivo analysis.

    PubMed

    Furustrand Tafin, Ulrika; Betrisey, Bertrand; Bohner, Marc; Ilchmann, Thomas; Trampuz, Andrej; Clauss, Martin

    2015-03-01

    Differences in physico-chemical characteristics of bone grafts to fill bone defects have been demonstrated to influence in vitro bacterial biofilm formation. Aim of the study was to investigate in vivo staphylococcal biofilm formation on different calcium phosphate bone substitutes. A foreign-body guinea-pig infection model was used. Teflon cages prefilled with β-tricalcium phosphate, calcium-deficient hydroxyapatite, or dicalcium phosphate (DCP) scaffold were implanted subcutaneously. Scaffolds were infected with 2 × 10(3) colony-forming unit of Staphylococcus aureus (two strains) or S. epidermidis and explanted after 3, 24 or 72 h of biofilm formation. Quantitative and qualitative biofilm analysis was performed by sonication followed by viable counts, and microcalorimetry, respectively. Independently of the material, S. aureus formed increasing amounts of biofilm on the surface of all scaffolds over time as determined by both methods. For S. epidermidis, the biofilm amount decreased over time, and no biofilm was detected by microcalorimetry on the DCP scaffolds after 72 h of infection. However, when using a higher S. epidermidis inoculum, increasing amounts of biofilm were formed on all scaffolds as determined by microcalorimetry. No significant variation in staphylococcal in vivo biofilm formation was observed between the different materials tested. This study highlights the importance of in vivo studies, in addition to in vitro studies, when investigating biofilm formation of bone grafts.

  20. Ambient Fine Particulate Matter Suppresses In Vivo Proliferation of Bone Marrow Stem Cells through Reactive Oxygen Species Formation

    PubMed Central

    Cui, Yuqi; Jia, Fengpeng; He, Jianfeng; Xie, Xiaoyun; Li, Zhihong; Fu, Minghuan; Hao, Hong; Liu, Ying; Liu, Dylan Z.; Cowan, Peter J.; Zhu, Hua; Sun, Qinghua; Liu, Zhenguo

    2015-01-01

    Aims Some environmental insults, such as fine particulate matter (PM) exposure, significantly impair the function of stem cells. However, it is unknown if PM exposure could affect the population of bone marrow stem cells (BMSCs). The present study was to investigate the effects of PM on BMSCs population and related mechanism(s). Main Metheods PM was intranasally distilled into male C57BL/6 mice for one month. Flow cytometry with antibodies for BMSCs, Annexin V and BrdU ware used to determine the number of BMSCs and the levels of their apoptosis and proliferation in vivo. Phosphorylated Akt (P-Akt) level was determined in the BM cells with western blotting. Intracellular reactive oxygen species (ROS) formation was quantified using flow cytometry analysis. To determine the role of PM-induced ROS in BMSCs population, proliferation, and apotosis, experiments were repeated using N-acetylcysteine (NAC)-treated wild type mice or a triple transgenic mouse line with overexpression of antioxidant network (AON) composed of superoxide dismutase (SOD)1, SOD3, and glutathione peroxidase-1 with decreased in vivo ROS production. Key Findings PM treatment significantly reduced BMSCs population in association with increased ROS formation, decreased P-Akt level, and inhibition of proliferation of BMSCs without induction of apoptosis. NAC treatment or AON overexpression with reduced ROS formation effectively prevented PM-induced reduction of BMSCs population and proliferation with partial recovery of P-Akt level. Significance PM exposure significantly decreased the population of BMSCs due to diminished proliferation via ROS-mediated mechanism (could be partially via inhibition of Akt signaling). PMID:26058063

  1. Fluoride’s Effects on the Formation of Teeth and Bones, and the Influence of Genetics

    PubMed Central

    Everett, E.T.

    2011-01-01

    Fluorides are present in the environment. Excessive systemic exposure to fluorides can lead to disturbances of bone homeostasis (skeletal fluorosis) and enamel development (dental/enamel fluorosis). The severity of dental fluorosis is also dependent upon fluoride dose and the timing and duration of fluoride exposure. Fluoride’s actions on bone cells predominate as anabolic effects both in vitro and in vivo. More recently, fluoride has been shown to induce osteoclastogenesis in mice. Fluorides appear to mediate their actions through the MAPK signaling pathway and can lead to changes in gene expression, cell stress, and cell death. Different strains of inbred mice demonstrate differential physiological responses to ingested fluoride. Genetic studies in mice are capable of identifying and characterizing fluoride-responsive genetic variations. Ultimately, this can lead to the identification of at-risk human populations who are susceptible to the unwanted or potentially adverse effects of fluoride action and to the elucidation of fundamental mechanisms by which fluoride affects biomineralization. PMID:20929720

  2. A Novel Low-Molecular-Weight Compound Enhances Ectopic Bone Formation and Fracture Repair

    PubMed Central

    Wong, Eugene; Sangadala, Sreedhara; Boden, Scott D.; Yoshioka, Katsuhito; Hutton, William C.; Oliver, Colleen; Titus, Louisa

    2013-01-01

    Background: Use of recombinant human bone morphogenetic protein-2 (rhBMP-2) is expensive and may cause local side effects. A small synthetic molecule, SVAK-12, has recently been shown in vitro to potentiate rhBMP-2-induced transdifferentiation of myoblasts into the osteoblastic phenotype. The aims of this study were to test the ability of SVAK-12 to enhance bone formation in a rodent ectopic model and to test whether a single percutaneous injection of SVAK-12 can accelerate callus formation in a rodent femoral fracture model. Methods: Collagen disks with rhBMP-2 alone or with rhBMP-2 and SVAK-12 were implanted in a standard athymic rat chest ectopic model, and radiographic analysis was performed at four weeks. In a second set of rats (Sprague-Dawley), SVAK-12 was percutaneously injected into the site of a closed femoral fracture. The fractures were analyzed radiographically and biomechanically (with torsional testing) five weeks after surgery. Results: In the ectopic model, there was dose-dependent enhancement of rhBMP-2 activity with use of SVAK-12 at doses of 100 to 500 μg. In the fracture model, the SVAK-12-treated group had significantly higher radiographic healing scores than the untreated group (p = 0.028). Biomechanical testing revealed that the fractured femora in the 200 to 250-μg SVAK-12 group were 43% stronger (p = 0.008) and 93% stiffer (p = 0.014) than those in the control group. In summary, at five weeks the femoral fracture group injected with SVAK-12 showed significantly improved radiographic and biomechanical evidence of healing compared with the controls. Conclusions: A single local dose of a low-molecular-weight compound, SVAK-12, enhanced bone-healing in the presence of low-dose exogenous rhBMP-2 (in the ectopic model) and endogenous rhBMPs (in the femoral fracture model). Clinical Relevance: This study demonstrates that rhBMP-2 responsiveness can be enhanced by a novel small molecule, SVAK-12. Local application of anabolic small molecules has

  3. Platelet lysate coating on scaffolds directly and indirectly enhances cell migration, improving bone and blood vessel formation.

    PubMed

    Leotot, Julie; Coquelin, Laura; Bodivit, Gwellaouen; Bierling, Philippe; Hernigou, Philippe; Rouard, Helene; Chevallier, Nathalie

    2013-05-01

    Suitable colonization and vascularization of tissue-engineered constructs after transplantation represent critical steps for the success of bone repair. Human platelet lysate (hPL) is composed of numerous growth factors known for their proliferative, differentiative and chemo-attractant effects on various cells involved in wound healing and bone growth. The aim of this study was to determine whether the delivery of human mesenchymal stromal cells (hMSC) seeded on hPL-coated hydroxyapatite/β-tricalcium phosphate (HA/β-TCP) scaffolds could enhance vascularization and bone formation, as well as to investigate the mechanisms by which hMSC participate in tissue regeneration. Our study demonstrates that hPL can be coated on HA/β-TCP scaffolds, which play direct and indirect effects on implanted and/or resident stem cells. Effectively, we show that hPL coating directly increases chemo-attraction to and adhesion of hMSC and endothelial cells on the scaffold. Moreover, we show that hPL coating induces hMSC to produce and secrete pro-angiogenic proteins (placental growth factor and vascular endothelial growth factor) which allow the proliferation and specific chemo-attraction of endothelial cells in vitro, thus improving in vivo neovascularization and new bone formation. This study highlights the potential of functionalizing biomaterials with hPL and shows that this growth factor combination can have synergistic effects leading to enhanced bone and blood vessel formation.

  4. Bone quality is affected by food restriction and by nutrition-induced catch-up growth.

    PubMed

    Pando, Rakefet; Masarwi, Majdi; Shtaif, Biana; Idelevich, Anna; Monsonego-Ornan, Efrat; Shahar, Ron; Phillip, Moshe; Gat-Yablonski, Galia

    2014-12-01

    Growth stunting constitutes the most common effect of malnutrition. When the primary cause of malnutrition is resolved, catch-up (CU) growth usually occurs. In this study, we have explored the effect of food restriction (RES) and refeeding on bone structure and mechanical properties. Sprague-Dawley male rats aged 24 days were subjected to 10 days of 40% RES, followed by refeeding for 1 (CU) or 26 days long-term CU (LTCU). The rats fed ad libitum served as controls. The growth plates were measured, osteoclasts were identified using tartrate-resistant acid phosphatase staining, and micro-computed tomography (CT) scanning and mechanical testing were used to study structure and mechanical properties. Micro-CT analysis showed that RES led to a significant reduction in trabecular BV/TV and trabecular number (Tb.N), concomitant with an increase in trabecular separation (Tb.Sp). Trabecular BV/TV and Tb.N were significantly greater in the CU group than in the RES in both short- and long-term experiments. Mechanical testing showed that RES led to weaker and less compliant bones; interestingly, bones of the CU group were also more fragile after 1 day of CU. Longer term of refeeding enabled correction of the bone parameters; however, LTCU did not achieve full recovery. These results suggest that RES in young rats attenuated growth and reduced trabecular bone parameters. While nutrition-induced CU growth led to an immediate increase in epiphyseal growth plate height and active bone modeling, it was also associated with a transient reduction in bone quality. This should be taken into consideration when treating children undergoing CU growth.

  5. Soy protein supplementation increases serum insulin-like growth factor-I in young and old men but does not affect markers of bone metabolism.

    PubMed

    Khalil, Dania A; Lucas, Edralin A; Juma, Shanil; Smith, Brenda J; Payton, Mark E; Arjmandi, Bahram H

    2002-09-01

    Recent studies suggest that soy protein (SP) protects bone in women; however, its effects on bone metabolism in men have not been investigated. Healthy men (59.2 +/- 17.6 y) were assigned to consume 40 g of either SP or milk-based protein (MP) daily for 3 mo in a double-blind, randomized, controlled, parallel design. Serum insulin-like growth factor-I (IGF-I), which is associated with higher rates of bone formation, was greater (P < 0.01) in men supplemented with SP than in those consuming MP. Serum alkaline phosphatase and bone-specific alkaline phosphatase activities, markers of bone formation, and urinary deoxypyridinoline excretion, a specific marker of bone resorption, were not different between the SP and MP groups. Furthermore, because substantial reductions in bone density occur in men at approximately 65 y of age, data were analyzed separately for men >/=65 y and those <65 y of age. The response to protein supplementation was consistent in the two age groups. The effects of SP on serum IGF-I levels suggest that SP may positively influence bone in men. Longer-duration studies examining the effects of SP or its isoflavones on bone turnover and bone mineral density and content in men are warranted.

  6. Preservation and promotion of bone formation in the mandible as a response to a novel calcium-phosphate based biomaterial in mineral deficiency induced low bone mass male versus female rats

    PubMed Central

    Srinivasan, Kritika; Naula, Diana P.; Mijares, Dindo Q.; Janal, Malvin N.; LeGeros, Raquel Z.; Zhang, Yu

    2016-01-01

    Calcium and other trace mineral supplements have previously demonstrated to safely improve bone quality. We hypothesize that our novel calcium-phosphate based biomaterial (SBM) preserves and promotes mandibular bone formation in male and female rats on mineral deficient diet (MD). Sixty Sprague-Dawley rats were randomly assigned to receive one of three diets (n = 10): basic diet (BD), MD or mineral deficient diet with 2% SBM. Rats were sacrificed after 6 months. Micro-Computed Tomography (μCT) was used to evaluate bone volume and 3D-microarchitecture while microradiography (Faxitron) was used to measure bone mineral density from different sections of the mandible. Results showed that bone quality varied with region, gender and diet. MD reduced bone mineral density (BMD) and volume and increased porosity. SBM preserved BMD and bone mineral content (BMC) in the alveolar bone and condyle in both genders. In the alveolar crest and mandibular body, while preserving more bone in males, SBM also significantly supplemented female bone. Results indicate that mineral deficiency leads to low bone mass in skeletally immature rats, comparatively more in males. Furthermore, SBM administered as a dietary supplement was effective in preventing mandibular bone loss in all subjects. This study suggests that the SBM preparation has potential use in minimizing low peak bone mass induced by mineral deficiency and related bone loss irrespective of gender. PMID:26914814

  7. Urinary calcium and oxalate excretion in healthy adult cats are not affected by increasing dietary levels of bone meal in a canned diet.

    PubMed

    Passlack, Nadine; Zentek, Jürgen

    2013-01-01

    This study aimed to investigate the impact of dietary calcium (Ca) and phosphorus (P), derived from bone meal, on the feline urine composition and the urinary pH, allowing a risk assessment for the formation of calcium oxalate (CaOx) uroliths in cats. Eight healthy adult cats received 3 canned diets, containing 12.2 (A), 18.5 (B) and 27.0 g Ca/kg dry matter (C) and 16.1 (A), 17.6 (B) and 21.1 g P/kg dry matter (C). Each diet was fed over 17 days. After a 7 dayś adaptation period, urine and faeces were collected over 2×4 days (with a two-day rest between), and blood samples were taken. Urinary and faecal minerals, urinary oxalate (Ox), the urinary pH and the concentrations of serum Ca, phosphate and parathyroid hormone (PTH) were analyzed. Moreover, the urine was microscopically examined for CaOx uroliths. The results demonstrated that increasing levels of dietary Ca led to decreased serum PTH and Ca and increased faecal Ca and P concentrations, but did not affect the urinary Ca or Ox concentrations or the urinary fasting pH. The urinary postprandial pH slightly increased when the diet C was compared to the diet B. No CaOx crystals were detected in the urine of the cats. In conclusion, urinary Ca excretion in cats seems to be widely independent of the dietary Ca levels when Ca is added as bone meal to a typical canned diet, implicating that raw materials with higher contents of bones are of subordinate importance as risk factors for the formation of urinary CaOx crystals.

  8. Porous Surface Modified Bioactive Bone Cement for Enhanced Bone Bonding

    PubMed Central

    Huang, Li; Dong, Jingjing; Guo, Dagang; Mao, Mengmeng; Kong, Liang; Li, Yang; Wu, Zixiang; Lei, Wei

    2012-01-01

    Background Polymethylmethacrylate bone cement cannot provide an adhesive chemical bonding to form a stable cement-bone interface. Bioactive bone cements show bone bonding ability, but their clinical application is limited because bone resorption is observed after implantation. Porous polymethylmethacrylate can be achieved with the addition of carboxymethylcellulose, alginate and gelatin microparticles to promote bone ingrowth, but the mechanical properties are too low to be used in orthopedic applications. Bone ingrowth into cement could decrease the possibility of bone resorption and promote the formation of a stable interface. However, scarce literature is reported on bioactive bone cements that allow bone ingrowth. In this paper, we reported a porous surface modified bioactive bone cement with desired mechanical properties, which could allow for bone ingrowth. Materials and Methods The porous surface modified bioactive bone cement was evaluated to determine its handling characteristics, mechanical properties and behavior in a simulated body fluid. The in vitro cellular responses of the samples were also investigated in terms of cell attachment, proliferation, and osteoblastic differentiation. Furthermore, bone ingrowth was examined in a rabbit femoral condyle defect model by using micro-CT imaging and histological analysis. The strength of the implant–bone interface was also investigated by push-out tests. Results The modified bone cement with a low content of bioactive fillers resulted in proper handling characteristics and adequate mechanical properties, but slightly affected its bioactivity. Moreover, the degree of attachment, proliferation and osteogenic differentiation of preosteoblast cells was also increased. The results of the push-out test revealed that higher interfacial bonding strength was achieved with the modified bone cement because of the formation of the apatite layer and the osseointegration after implantation in the bony defect. Conclusions

  9. Effects of cigarette smoke inhalation and coffee consumption on bone formation and osseous integration of hydroxyapatite implant.

    PubMed

    Andrade, A R; Sant'Ana, D C M; Mendes, J A; Moreira, M; Pires, G C; Santos, M P; Fernandes, G J M; Nakagaki, W R; Garcia, J A D; Lima, C C; Soares, E A

    2013-02-01

    The present study aims to assess the effects of cigarette smoke inhalation and/or coffee consumption on bone formation and osseous integration of a dense hydroxyapatite (DHA) implant in rats. For this study, 20 male rats were divided into four groups (n = 5): CT (control) group, CE (coffee) group, CI (cigarette) group and CC (coffee + cigarette) group. During 16 weeks, animals in the CI group were exposed to cigarette smoke inhalation equivalent to 6 cigarettes per day; specimens in the CE group drank coffee as liquid diet; and rats in the CC group were submitted to both substances. In the 6th week a 5 mm slit in the parietal bone and a 4 mm slit in the tibia were performed on the left side: the former was left open while the latter received a DHA implant. As soon as surgeries were finished, the animals returned to their original protocols and after 10 weeks of exposure they were euthanised (ethically sacrificed) and the mentioned bones collected for histological processing. Data showed that exposure to cigarette smoke inhalation and coffee consumption did not interfere in weight gain and that solid and liquid diet consumption was satisfactory. Rats in the CC group showed a decrease in bone neoformation around the tibial DHA implant (31.8 ± 2.8) as we