transforming-growth-factor-beta and Osteoporosis

Bone material strength is determined by several factors, such as bone mass, matrix composition, mineralization, architecture and shape. From a clinical perspective, bone fragility is classified as primary (i.e., genetic and rare) or secondary (i.e., acquired and common) osteoporosis. Understanding the mechanism of rare genetic bone fragility disorders not only advances medical knowledge on rare diseases, it may open doors for drug development for more common disorders (i.e., postmenopausal osteoporosis). In this review, we highlight the main disease mechanisms underlying the development of human bone fragility associated with low bone mass known to date. The pathways we focus on are type I collagen processing, WNT-signaling, TGF-ß signaling, the RANKL-RANK system and the osteocyte mechanosensing pathway. We demonstrate how the discovery of most of these pathways has led to targeted, pathway-specific treatments.

Topics: Collagen Type I; Humans; Osteogenesis Imperfecta; Osteoporosis; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Transforming Growth Factor beta; Wnt Signaling Pathway

There have been a number of reports that chronic antiepileptic drug (AEDs) therapy is associated with abnormal bone and calcium metabolism, osteoporosis/osteomalacia, and increased risk of fractures. Bony adverse effects of long term antiepileptic drug therapy have been reported for more than four decades but the exact molecular mechanism is still lacking. Several mechanisms have been proposed regarding AEDs induced bone loss; Hypovitaminosis D, hyperparathyroidism, estrogen deficiency, calcitonin deficiency. Transforming growth factor-β (TGF- β) is abundant in bone matrix and has been shown to regulate the activity of osteoblasts and osteoclasts in vitro. All isoforms of TGF- β are expressed in bone and intricately play role in bone homeostasis by modulating estrogen level. Ovariectomised animal have shown down regulation of TGF- β in bone that could also be a probable target of AEDs therapy associated bone loss. One of the widely accepted hypotheses regarding the conventional drugs induced bone loss is hypovitaminosis D which is by virtue of their microsomal enzyme inducing effect. However, despite of the lack of enzyme inducing effect of certain newer antiepileptic drugs, reduced bone mineral density with these drugs have also been reported. Thus an understanding of bone biology, pathophysiology of AEDs induced bone loss at molecular level can aid in the better management of bone loss in patients on chronic AEDs therapy. This review focuses mainly on certain new molecular targets of AEDs induced bone loss.

Topics: Anticonvulsants; Bone Density; Bone Diseases, Metabolic; Osteoporosis; Transforming Growth Factor beta

Bone mineral density, a bone matrix parameter frequently used to predict fracture risk, is not the only one to affect bone fragility. Other factors, including the extracellular matrix (ECM) composition and microarchitecture, are of paramount relevance in this process. The bone ECM is a noncellular three-dimensional structure secreted by cells into the extracellular space, which comprises inorganic and organic compounds. The main inorganic components of the ECM are calcium-deficient apatite and trace elements, while the organic ECM consists of collagen type I and noncollagenous proteins. Bone ECM dynamically interacts with osteoblasts and osteoclasts to regulate the formation of new bone during regeneration. Thus, the composition and structure of inorganic and organic bone matrix may directly affect bone quality. Moreover, proteins that compose ECM, beyond their structural role have other crucial biological functions, thanks to their ability to bind multiple interacting partners like other ECM proteins, growth factors, signal receptors and adhesion molecules. Thus, ECM proteins provide a complex network of biochemical and physiological signals. Herein, we summarize different ECM factors that are essential to bone strength besides, discussing how these parameters are altered in pathological conditions related with bone fragility.

Topics: Animals; Bone and Bones; Bone Density; Bone Matrix; Collagen; Extracellular Matrix; Extracellular Matrix Proteins; Fractures, Bone; Homeostasis; Humans; Integrins; Matrix Metalloproteinases; Osteoblasts; Osteoclasts; Osteogenesis Imperfecta; Osteoporosis; Signal Transduction; Transforming Growth Factor beta; Wnt Proteins

Osteoblasts are terminally differentiated cells with mesenchymal origins, known to possess pivotal roles in sustaining bone microstructure and homeostasis. These cells are implicated in the pathophysiology of various bone disorders, especially osteoporosis. Over the last few decades, strategies to impede bone resorption, principally by bisphosphonates, have been mainstay of treatment of osteoporosis; however, in recent years more attention has been drawn on bone-forming approaches for managing osteoporosis. MicroRNAs (miRNAs) are a broad category of noncoding short sequence RNA fragments that posttranscriptionally regulate the expression of diverse functional and structural genes in a negative manner. An accumulating body of evidence signifies that miRNAs direct mesenchymal stem cells toward osteoblast differentiation and bone formation through bone morphogenic protein, transforming growth factor-β, and Wnt signaling pathways. MiRNAs are regarded as excellent future therapeutic candidates because of their small size and ease of delivery into the cells. Considering their novel therapeutic significance, this review discusses the main miRNAs contributing to the anabolic aspects of bone formation and illustrates their interactions with corresponding signaling pathways involved in osteoblastic differentiation.

Topics: Bone Morphogenetic Proteins; Cell Differentiation; Humans; Mesenchymal Stem Cells; MicroRNAs; Osteoblasts; Osteogenesis; Osteoporosis; Signal Transduction; Transforming Growth Factor beta; Wnt Proteins

Numerous forms of osteoporosis in childhood are characterized by low bone turnover (for example, osteoporosis due to neuromuscular disorders and glucocorticoid exposure). Anti-resorptive therapy, traditionally used to treat osteoporosis in the young, is associated with further reductions in bone turnover, raising concerns about the long-term safety and efficacy of such therapy. These observations have led to increasing interest in the role of anabolic therapy to treat pediatric osteoporosis.. While growth hormone and androgens appears to be relatively weak anabolic modulators of bone mass, emerging therapies targeting bone formation pathways (anti-transforming growth factor beta antibody and anti-sclerostin antibody) hold considerable promise. Teriparatide remains an attractive option that merits formal study for patients post-epiphyseal fusion, although it must be considered that adult studies have shown its effect is blunted when administered following bisphosphonate therapy. Mechanical stimulation of bone through whole body vibration therapy appears to be much less effective than bisphosphonate therapy for treating osteoporosis in children. New anabolic therapies which target important pathways in skeletal metabolism merit further study in children, including their effects on fracture risk reduction and after treatment discontinuation.

Topics: Adaptor Proteins, Signal Transducing; Anabolic Agents; Androgens; Antibodies; Bone Density Conservation Agents; Bone Morphogenetic Proteins; Child; Genetic Markers; Human Growth Hormone; Humans; Osteoporosis; Teriparatide; Testosterone; Transforming Growth Factor beta; Vibration

In this review, we present the role of regulatory T (Treg) cells in bone remodelling and bone-related disease such as osteoporosis or inflammatory bone loss. We also discuss the cellular and molecular mechanism how Treg cells regulate osteoclastogenesis.. Treg cells could regulate osteoclastogenesis by secreting TGF-β and IL-10 as well as IL-4 cytokines. Moreover, Treg cells can additionally regulate osteoclast differentiation, in a cell-to-cell contact via the cytotoxic T lymphocyte antigen (CTLA-4). The latter induces the apoptosis of osteoclasts dependent on CD80/86 in vitro and in vivo. Treg cells mediate immunosuppressive function that controls undesired immune reactions, such as autoimmunity. Recently, Treg cells have been shown to influence non-immunological processes, such as bone homeostasis. Accumulated evidences have demonstrated that Treg cells can suppress osteoclast differentiation in vitro and in vivo.

Topics: Apoptosis; Bone Remodeling; CTLA-4 Antigen; Humans; Interleukin-10; Interleukin-4; Osteoclasts; Osteogenesis; Osteoporosis; T-Lymphocytes, Regulatory; Transforming Growth Factor beta

Secreted phosphoprotein 24 kD (Spp24) is a bone matrix protein that appears to be derived primarily from the liver and delivered to other tissues in a protective complex. A significant role in bone growth and turnover is suggested by genetic studies that associate the gene locus (SPP2) with bone mineral density and bone quality. The function of this protein in the normal bone environment is unknown but clues are given by the fact that Spp24, or proteolytic products of Spp24, bind cytokines of the TGF-β superfamily and also activate intracellular signaling pathways. Several potential biotherapeutics have been engineered from this protein including materials that enhance BMP-induced bone healing and, on the other hand, materials that inhibit BMPs in clinical situations where this is called for such as reducing BMP-induced inflammation and inhibiting tumors dependent on BMP autocrine systems. As understanding of the structure and function of this protein increases, more opportunities for rationally developed therapeutics will become apparent.

Topics: Animals; Bone and Bones; Bone Density; Bone Matrix; Bone Morphogenetic Proteins; Cattle; Chick Embryo; Cytokines; HEK293 Cells; Humans; Inflammation; Mice; Osteoporosis; Phosphoproteins; Signal Transduction; Transforming Growth Factor beta

Healing fractures resulting from osteoporosis or cancer remains a significant clinical challenge. In these populations, healing is often impaired not only due to age and disease, but also by other therapeutic interventions such as radiation, steroids, and chemotherapy. Despite substantial improvements in the treatment of osteoporosis over the last few decades, osteoporotic fractures are still a major clinical challenge in the elderly population due to impaired healing. Similar fractures with impaired healing are also prevalent in cancer patients, especially those with tumor growing in bone. Treatment options for cancer patients are further complicated by the fact that bone anabolic therapies are contraindicated in patients with tumors. Therefore, many patients undergo surgery to repair the fracture, and bone grafts are often used to stabilize orthopedic implants and provide a scaffold for ingrowth of new bone. Both synthetic and naturally occurring biomaterials have been investigated as bone grafts for repair of osteoporotic fractures, including calcium phosphate bone cements, resorbable polymers, and allograft or autograft bone. In order to re-establish normal bone repair, bone grafts have been augmented with anabolic agents, such as mesenchymal stem cells or recombinant human bone morphogenetic protein-2. These developing approaches to bone grafting are anticipated to improve the clinical management of osteoporotic and cancer-induced fractures.

Topics: Biocompatible Materials; Bone Morphogenetic Protein 2; Bone Neoplasms; Bone Transplantation; Fracture Fixation; Fractures, Spontaneous; Humans; Orthopedic Fixation Devices; Osteoporosis; Osteoporotic Fractures; Parathyroid Hormone; Recombinant Proteins; Tissue Scaffolds; Transforming Growth Factor beta

The class of small leucine-rich proteoglycans (SLRPs) is a family of homologous proteoglycans harboring relatively small (36-42 kDa) protein cores compared with the larger cartilage and mesenchymal proteoglycans. SLRPs have been localized to most skeletal regions, with specific roles designated during all phases of bone formation, including periods relating to cell proliferation, organic matrix deposition, remodeling, and mineral deposition. This is mediated by key signaling pathways regulating the osteogenic program, including the activities of TGF-β, bone morphogenetic protein, Wnt, and NF-κB, which influence both the number of available osteogenic precursors and their subsequent development, differentiation, and function. On the other hand, SLRP depletion is correlated with degenerative diseases such as osteoporosis and ectopic bone formation. This minireview will focus on the SLRP roles in bone physiology and pathology.

Topics: Animals; Bone Morphogenetic Proteins; Bone Remodeling; Calcification, Physiologic; Extracellular Matrix Proteins; Humans; NF-kappa B; Osteogenesis; Osteoporosis; Proteoglycans; Transforming Growth Factor beta; Wnt Signaling Pathway

Follistatin is a monomeric glycoprotein, distributed in a wide range of tissues. Recent work has demonstrated that this protein is a pluripotential molecule that has no structural similarity but is functionally associated with members of the transforming growth factor (TGF)-β superfamily, which indicates its wide range of action. Members of the TGF-β superfamily, especially activins and bone morphogenetic proteins are involved in bone metabolism. They play an important role in bone physiology, influencing bone growth, turnover, bone formation and cartilage induction. As follistatin is considered to be the antagonist of the TGF-β superfamily members, it plays an important role in bone metabolism and development.

Topics: Bone and Bones; Bone Neoplasms; Follistatin; Humans; Osteoporosis; Transforming Growth Factor beta

Topics: Biocompatible Materials; Bone Density; Durapatite; Humans; Osteoporosis; Somatomedins; Transforming Growth Factor beta

It was previously believed that obesity and osteoporosis were two unrelated diseases, but recent studies have shown that both diseases share several common genetic and environmental factors. Body fat mass, a component of body weight, is one of the most important indices of obesity, and a substantial body of evidence indicates that fat mass may have beneficial effects on bone. Contrasting studies, however, suggest that excessive fat mass may not protect against osteoporosis or osteoporotic fracture. Differences in experimental design, sample structure, and even the selection of covariates may account for some of these inconsistent or contradictory results. Despite the lack of a clear consensus regarding the impact of effects of fat on bone, a number of mechanistic explanations have been proposed to support the observed epidemiologic and physiologic associations between fat and bone. The common precursor stem cell that leads to the differentiation of both adipocytes and osteoblasts, as well the secretion of adipocyte-derived hormones that affect bone development, may partially explain these associations. Based on our current state of knowledge, it is unclear whether fat has beneficial effects on bone. We anticipate that this will be an active and fruitful focus of research in the coming years.

Topics: 11-beta-Hydroxysteroid Dehydrogenases; Adipocytes; Adiponectin; Adipose Tissue; Amyloid; Aromatase; Bone Density; Cell Differentiation; Female; Humans; Insulin; Insulin-Like Growth Factor II; Interleukin-6; Islet Amyloid Polypeptide; Leptin; Male; Obesity; Osteoblasts; Osteoporosis; Peptide Fragments; PPAR gamma; Resistin; Transforming Growth Factor beta; Wnt Proteins

Bone mass declines progressively with age in both men and women from the age of approximately 30 y. Increased longevity will inevitability be associated with an increase in the incidence of osteoporosis, its associated complications, and incurred health care costs. Current pharmacologic approaches focus on inhibiting bone resorption in those with osteoporosis but do little to improve bone mass. Increased understanding of the cellular events responsible for normal bone formation has led to multiple pathways that can be targeted to positively influence bone mass. Bone morphogenetic proteins (BMPs) have been shown to stimulate bone formation, and the BMP2 gene was recently linked to osteoporosis. BMP-2 therefore represents one potential molecular target to identify new agents to simulate bone formation. Research is accumulating on the positive effects of dietary sources that stimulate the BMP2 promoter and their effects on bone formation. Flavonoids and statins occur naturally in food products and have been shown to promote bone formation. It may be possible to influence peak bone mass by dietary means and to decrease the risk of osteoporosis in later life. To ease the future burden of osteoporosis, focusing on prevention will be key, and this could include dietary interventions to stimulate bone formation.

Topics: Aged; Aging; Bone and Bones; Bone Density; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Bone Remodeling; Diet; Dietary Supplements; Humans; Osteoporosis; Transforming Growth Factor beta

3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) are potent inhibitors of cholesterol biosynthesis. Cholesterol-lowering therapy using statins significantly reduces the risk of coronary heart disease. However, extensive use of statins leads to increases of other undesirable as well as beneficial effects, so-called pleiotropic effects. With respect to these effects, statins augment the expression of bone morphogenetic protein-2, a potent simulator of osteoblast differentiation and its activity, and promote mineralization by cultured osteoblasts, indicating that statins have an anabolic effect on bone. Chronic administration of statins in ovariectomized (OVX) rats modestly increases bone mineral density (BMD) of cancellous bone but not of compact bone. In clinical studies, there are conflicting results regarding the clinical benefits of this therapy for the treatment of osteoporosis. Observational studies suggest an association between statin use and reduction in fracture risk. Clinical trials reported no effect of statin treatment on BMD in hip and spine, and on bone turnover. Statins also may influence oral osseous tissues. Administration of statins in combination with osteoporosis therapy appears to improve alveolar bone architecture in the mandibles of OVX rats with maxillary molar extraction. Statins continue to be considered as potential therapeutic agents for patients with osteoporosis and possibly with periodontal disease. Development of new statins that are more specific and potent for bone metabolism will greatly increase the usefulness of these drugs for the treatment of bone diseases.

Topics: Alveolar Process; Animals; Anticholesteremic Agents; Bone and Bones; Bone Density; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Cell Differentiation; Fractures, Bone; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Osteoblasts; Osteoporosis; Transforming Growth Factor beta

Total joint arthroplasty is very effective for improving the quality of life of patients with end-stage arthritis. Despite advances in materials, surgical technique, and rehabilitation regimens, joint replacements are still fraught with complications leading to their premature failure. Aseptic loosening and osteolysis are the primary causes of implant failure. Other reasons include early migration of components leading to instability, lack of ingrowth into implant porosities, and bone loss caused by stress shielding. Pharmaceutical agents used for preventing and managing postmenopausal osteoporosis (eg, bisphosphonates) may in the future play an important role in improving the long-term duration of joint arthroplasties. Early findings indicate that bisphosphonates upregulate bone morphogenetic protein-2 production and stimulate new bone formation. Because of their anabolic effect on osteoblasts, bisphosphonates have the potential to enhance bone ingrowth into implant porosities, prevent bone resorption under adverse conditions, and dramatically extend the long-term durability of joint arthroplasties. The long-term effects of bisphosphonate use on the mechanical properties of bone have not been adequately investigated. Along with improvements in implant design and material properties, bisphosphonates and other pharmaceutical agents may, in the near future, be part of the growing armamentarium that provides more durable joint arthroplasties.

Topics: Arthroplasty, Replacement, Knee; Bed Rest; Bone Density Conservation Agents; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Bone Resorption; Diphosphonates; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Osseointegration; Osteogenesis; Osteoporosis; Prosthesis Failure; Transforming Growth Factor beta

Osteoporosis is a common disease with a strong genetic component characterized by reduced bone mass and increased risk of fragility fractures. Twin and family studies have shown that the heritability of bone mineral density (BMD) and other determinants of fracture risk-such as ultrasound properties of bone, skeletal geometry, and bone turnover-is high, although heritability of fracture is modest. Many different genetic variants of modest effect size are likely to contribute to the regulation of these phenotypes by interacting with environmental factors such as diet and exercise. Linkage studies in rare Mendelian bone diseases have identified several previously unknown genes that play key roles in regulating bone mass and bone turnover. In many instances, subtle polymorphisms in these genes have also been found to regulate BMD in the general population. Although there has been extensive progress in identifying the genetic variants that regulate susceptibility to osteoporosis, most of the genes and genetic variants that regulate bone mass and susceptibility to osteoporosis remain to be discovered.

Topics: Animals; Bone Density; Bone Morphogenetic Proteins; Calcium; Collagen Type I; Collagen Type I, alpha 1 Chain; Core Binding Factor Alpha 1 Subunit; Disease Models, Animal; Estrogen Receptor alpha; Female; Genetic Linkage; Humans; LDL-Receptor Related Proteins; Low Density Lipoprotein Receptor-Related Protein-5; Male; Models, Biological; Osteoporosis; Signal Transduction; Transforming Growth Factor beta; Transforming Growth Factor beta1

Over the past 10 years, many advances have been made in understanding the mechanisms by which genetic factors regulate susceptibility to osteoporosis. It has become clear from studies in man and experimental animals that different genes regulate BMD at different skeletal sites and in men and women. Linkage studies have identified several chromosomal regions that regulate BMD, but only a few causative genes have been discovered so far using this approach. In contrast, significant advances have been made in identifying the genes that cause monogenic bone diseases, and polymorphic variation is some of these genes has been found to contribute to the genetic regulation of BMD in the normal population. Other genes that have been investigated as possible candidates for susceptibility to osteoporosis because of their role in bone biology, such as vitamin D, have yielded mixed results. Many candidate gene association studies have been underpowered, and meta-analysis has been used to try to confirm or refute potential associations and gain a better estimate of their true effect size in the population. Most of the genetic variants that confer susceptibility to osteoporosis remain to be discovered. It is likely that new techniques such as whole-genome association will provide new insights into the genetic determinants of osteoporosis and will help to identify genes of modest effect size. From a clinical standpoint, genetic variants that are found to predispose to osteoporosis will advance our understanding of the pathophysiology of the disease. They could be developed as diagnostic genetic tests or form molecular targets for design of new drugs for the prevention and treatment of osteoporosis and other bone diseases.

Topics: Animals; Core Binding Factor Alpha 1 Subunit; Estrogen Receptor alpha; Humans; LDL-Receptor Related Proteins; Low Density Lipoprotein Receptor-Related Protein-5; Osteoporosis; Receptors, Calcitriol; Transforming Growth Factor beta

Topics: Animals; Bone and Bones; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Bone Remodeling; Drug Design; Gene Expression Regulation, Developmental; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Osteoporosis; Transforming Growth Factor beta

Topics: Animals; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Clinical Trials as Topic; Drug Design; Fractures, Bone; Gene Expression Regulation, Developmental; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Intracellular Signaling Peptides and Proteins; Oligopeptides; Osteoblasts; Osteogenesis; Osteoporosis; Proteasome Inhibitors; Protein Serine-Threonine Kinases; rho GTP-Binding Proteins; rho-Associated Kinases; Transforming Growth Factor beta

Topics: Animals; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Bone Regeneration; Bone Transplantation; Collagen Type I; Drug Carriers; Drug Design; Humans; Osteogenesis; Osteoporosis; Transforming Growth Factor beta

Topics: Animals; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Bone Resorption; Cell Division; Clinical Trials as Topic; Fractures, Bone; Gene Expression; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Hypolipidemic Agents; Osteoblasts; Osteogenesis; Osteoporosis; Stimulation, Chemical; Transforming Growth Factor beta

Topics: Acyl Coenzyme A; Animals; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Bone Resorption; Cell Differentiation; Diphosphonates; Fractures, Bone; GTP-Binding Proteins; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Mevalonic Acid; Osteoblasts; Osteoclasts; Osteogenesis; Osteoporosis; Polyisoprenyl Phosphates; Protein Prenylation; Sesquiterpenes; Signal Transduction; Transforming Growth Factor beta

Osteoporosis is characterised by excess bone fragility resulting from bone loss and altered bone microarchitecture. Bone loss occurring during aging and after menopause in women is known to result from an imbalance between bone formation and resorption. Bone formation is dependent on the commitment of osteoprogenitor cells, the proliferation of pre-osteoblasts, their differentiation into mature osteoblasts synthesising bone matrix and the life-span of mature osteoblasts. Transforming Growth Factor beta (TGFbeta) and Fibroblast Growth Factors (FGFs) are important factors that promote osteoprogenitor cell proliferation and osteogenesis. Reduced expression of TGFbeta in bone was found in several animal models of osteopenia. In addition, both FGF and TGFbeta were found to exert anabolic effects on bone formation in intact animals and to reduce bone loss in experimental models of osteoporosis. Both genetic manipulation of FGF and TGFbeta or their receptors in mice and bone phenotype associated with FGF receptors and TGFbeta mutations or polymorphism suggest that TGFbeta and FGF signalling may contribute to the control of osteogenesis and bone mass in vivo. The determination of molecular mechanisms involved in the anabolic actions of FGF and TGFbeta in cells of the osteoblastic lineage may lead in the future to the development of new therapeutic strategies aimed at improving bone formation in osteoporotic patients.

Topics: Animals; Bone Development; Fibroblast Growth Factors; Growth Substances; Humans; Osteoporosis; Transforming Growth Factor beta

Major advances in our knowledge about the genetic determinants of osteoporosis have been made in recent years. They include the discovery of genes responsible for monogenic bone diseases associated with abnormal bone mass; the identification of quantitative trait loci for bone mass in the general population and in mice; and the characterisation of several candidate genes for osteoporosis. Information from these studies is being used to design new drugs for osteoporosis and to develop genetic markers for fracture risk assessment.

Topics: Animals; Bone Density; Collagen Type I; Estrogens; Genetic Predisposition to Disease; Genetic Therapy; Humans; Interleukin-6; Mice; Osteoporosis; Quantitative Trait Loci; Transforming Growth Factor beta; Vitamin D

Osteoporosis is characterized by a decrease in bone mass as well as a deterioration of the bone architecture resulting in an increased risk of fracture. The disease is multifactorial, and it depends on environmental and genetic factors. Twin studies have shown that genetic factors account for 60-80% of the variance in bone mineral density, the best predictor of the risk of osteoporosis. There are different approaches to identify these genetic factors. Linkage studies in human and experimental animals have defined multiple loci that regulate bone mass but most of the genes responsible for this effect remain to be defined. The 11q12-13 locus was the first that was linked to bone mineral density of the young female and special bone diseases like high bone mass syndrome and osteoporosis-pseudoglioma syndrome. Both diseases appear to be in association with LDL receptor-related protein 5 gene mutation. The effect of LDL receptor-related protein 5 on bone metabolism had not been known only genetic methods suggested it. The effect of LRP5 in osteoporosis pathogenesis requires more investigation. Association and linkage studies have been performed in order to identify candidate genes in the pathogenesis of osteoporosis. Vitamin D receptor gene was the first candidate, however its effect is controversial. Other candidates, such as insulin like growth factor, interleukin-6, estrogen receptor alpha, transforming growth factor beta show no or small effect on bone mineral density or fracture frequency. To date only Sp1 polymorphism of collagen gene seems to have a consistent effect on bone fragility. The improved understanding of osteoporosis genetics should lead to better diagnosis of this disease and new treatment and prevention strategies.

Topics: Animals; Bone Density; Bone Diseases; Collagen Type I; Disease Models, Animal; Estrogen Receptor alpha; Female; Genetic Linkage; Humans; LDL-Receptor Related Proteins; Low Density Lipoprotein Receptor-Related Protein-5; Mice; Mice, Transgenic; Osteoporosis; Osteoporosis, Postmenopausal; Receptors, Calcitriol; Receptors, Estrogen; Receptors, LDL; Transforming Growth Factor beta

Mesenchymal stem cells possess the ability to differentiate into osteoblasts, chondroblasts, lipoblasts, myoblasts and so on, which can be used in the formation of hematopoietic microenvironment, tissue repairing and gene therapy. Growth factors such as TGF-beta, IGF-I, BMP and FGF can influence on the differentiation of MSC and they cooperate with each other. MSCs support hematopoiesis by secreting cytokines including G-CSF, SCF, LIF, M-CSF, IL-6, IL-11 and are related to some diseases. MSC would demonstrate important effect on gene engineering.

Topics: Animals; Bone Morphogenetic Proteins; Cytokines; Fibroblast Growth Factors; Genetic Engineering; Humans; Mesoderm; Multiple Sclerosis; Osteoporosis; Stem Cells; Transforming Growth Factor beta

Topics: Animals; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Fatty Acids, Monounsaturated; Fluvastatin; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Hypolipidemic Agents; Indoles; Lovastatin; Mevalonic Acid; Osteogenesis; Osteoporosis; Stimulation, Chemical; Transforming Growth Factor beta

The statins may not only lower cholesterol, they may stimulate bone formation, as suggested by a number of observational studies and animal research. Whether these drugs will be of benefit in treating osteoporosis awaits further clinical trials.

Topics: Animals; Bone Density; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Female; Fractures, Bone; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Mevalonic Acid; Osteogenesis; Osteoporosis; Transforming Growth Factor beta

Inhibitors of the 3-hydroxy-3-methylglutaryl coenzyme A reductase enzyme have recently been shown to stimulate bone formation in rodents both in vitro and in vivo. In bone cells, these inhibitors increase the gene expression of bone morphogenetic protein-2, which is an autocrine-paracrine factor for osteoblast differentiation. The findings that statins increase bone formation and bone mass in rodents suggest a potential new action for these compounds, which may be beneficial in patients with established osteoporosis where marked bone loss has occurred. Recent clinical data suggest that they may reduce the risk of fracture in patients taking these drugs.

Topics: Animals; Animals, Newborn; Bone and Bones; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Female; Fractures, Spontaneous; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; In Vitro Techniques; Mice; Osteoblasts; Osteogenesis; Osteoporosis; Rats; RNA, Messenger; Transforming Growth Factor beta

Vitamin D is the major regulator of calcium homeostasis and protects the organism from calcium deficiency via effects on the intestine, kidney, parathyroid gland, and bone. Disturbances in the vitamin D endocrine system (e.g., vitamin D-dependent rickets type I and type II), result in profound effects on the mineralization of bone. Recent studies with vitamin D receptor knockout mice also show effects on bone. It is questioned whether vitamin D has a direct effect on bone formation and mineralization. In rickets and particular vitamin D receptor knockout mice, calcium supplementation restores bone mineralization. However, the vitamin D receptor is present in osteoblasts, and vitamin D affects the expression of various genes in osteoblasts. This review focuses on the role of vitamin D in the control of osteoblast function and discusses the current knowledge of the direct effects of vitamin D on mineralization. Moreover, the role of vitamin D metabolism and the mechanism of action of vitamin D and interaction with other hormones and factors are discussed.

Topics: Alkaline Phosphatase; Animals; Apoptosis; Bone Morphogenetic Proteins; Calcifediol; Calcification, Physiologic; Calcitriol; Calcium-Binding Proteins; Cell Division; Cell Line; Cytochrome P-450 Enzyme System; Extracellular Matrix; Extracellular Matrix Proteins; Gene Expression Regulation; Humans; Insulin-Like Growth Factor I; Integrin-Binding Sialoprotein; Matrix Gla Protein; Mice; Mice, Knockout; Minerals; Osteoblasts; Osteocalcin; Osteoclasts; Osteonectin; Osteopontin; Osteoporosis; Plasminogen; Prostaglandins; Rats; Receptors, Calcitriol; Rickets; Sialoglycoproteins; Steroid Hydroxylases; Transforming Growth Factor beta; Vitamin D; Vitamin D Deficiency; Vitamin D3 24-Hydroxylase

Osteoporosis exhibits a substantial genetic component. Although polymorphisms of a variety of genes have been associated with bone mineral density and genetic susceptibility to osteoporosis, the genes responsible for these traits have not been definitively identified. We have shown that a T869-->C polymorphism of the transforming growth factor-beta1 gene, which results in a Leu-->Pro substitution at amino acid 10, is associated with bone mineral density in Japanese adolescents and postmenopausal women, with genetic susceptibility to both osteoporosis and vertebral fracture, and with the outcome of treatment for osteoporosis with active vitamin D. We have also shown that a C-509-->T polymorphism in the promoter region of this gene is associated with both bone mineral density and the prevalence of osteoporosis in postmenopausal women. In addition, analysis of combined genotypes for both the C-509-->T and T869-->C polymorphisms revealed that bone mineral density decreases and the susceptibility to osteoporosis increases with the number of T alleles. Thus, combined genotyping of the C-509-->T and T869-->C polymorphisms may prove beneficial in the prevention of osteoporosis in postmenopausal Japanese women. I review here the association of transforming growth factor-beta1 gene polymorphisms with genetic susceptibility to osteoporosis, which has provided insight into the function of transforming growth factor-beta1 as well as into the role of genetic factors in the development of osteoporosis.

Topics: Adolescent; Aged; Bone Density; Female; Genetic Predisposition to Disease; Humans; Japan; Male; Osteoporosis; Polymorphism, Single Nucleotide; Radiography; Radius; Spinal Injuries; Transforming Growth Factor beta; Transforming Growth Factor beta1; Treatment Outcome; Vitamin D

Transforming growth factor beta (TGF beta) is unique among growth factors in its potent and widespread actions. Almost every cell in the body has been shown to make some form of TGF beta, and almost every cell has receptors for TGF beta. Therefore, it becomes apparent that this growth factor must be tightly regulated to prevent disease. The mechanisms of regulation of TGF beta are extensive and complex. One set of mechanisms centers around the fact that TGF beta is produced in a latent form that must be activated to produce biologically active TGF beta. These mechanisms include the latency of the molecule, the production of various latent forms, its targeting to cells for activation or to matrix for storage, and the means of activation of the latent forms. The TGF beta isoforms and the types, affinity, and signaling functions of its receptors also add complexity to the regulation of the effects of TGF beta. Active TGF beta regulates numerous processes in the body. TGF beta has three major biological effects: growth inhibition, stimulation of extracellular matrix formation, and immunosuppression. The means by which TGF beta regulates the expression of the numerous genes on which it has effects are complex and more information is needed. The means by which TGF beta regulates gene expression and the means by which the actions of TGF beta are regulated are addressed in this review.

Topics: Animals; Cell Division; Extracellular Matrix; Gene Expression Regulation; Gene Targeting; Immunosuppression Therapy; Osteoporosis; Protein Isoforms; Receptors, Transforming Growth Factor beta; Signal Transduction; Transforming Growth Factor beta

Family and twin studies have established a genetic contribution to the etiology of osteoporosis. The genes and allelic variants conferring osteoporotic risk are largely undefined, but the number of candidates has increased steadily in recent years (Table I). Osteoporosis is a complex disease, and allelic variation in many other candidate-genes including those that encode growth factors, cytokines, calciotropic hormones, and bone matrix proteins are likely to also play a role and warrant systematic investigation. Most family and association studies to date have focused on the genetic contributions to bone density, a major determinant of bone strength and fracture risk. Bone density is not the only determinant of skeletal fragility, however, and genetic influences on fracture risk are independent of bone density [Cummings et al., 1995]. The microarchitectural properties and overall size and geometry of bone also influence skeletal strength [Bouxsein et al., 1996], and the genetic influences on these phenotypes should be investigated more rigorously. Even fewer studies have assessed the association between candidate-gene variation and the risk of fracture, the most important clinical outcome of osteoporosis. Large-scale molecular epidemiologic studies will be increasingly necessary in the future to quantify the relative, absolute and attributable risks of fracture associated with specific genetic variants. Osteoporosis is a complex, multifactorial disease, and most candidate-gene association studies have had limited statistical power to assess gene-gene and gene-environment interaction. Although gender plays an important role in the development of osteoporosis, genetic studies have almost exclusively focused on women, and have not tested whether gender modifies the association between genetic variation and osteoporotic risk. Therefore, future genetic studies will need to recruit larger samples of individuals including men. Rapid additional progress in our understanding of the molecular basis of osteoporosis can be expected in the near future as ongoing genome-wide linkage [Spotila et al., 1996] and candidate-gene association analyses are completed. Linkage analyses in families at high-risk for rare metabolic bone diseases should also yield important clues to the pathogenesis of osteoporosis. Recent examples are the mapping of loci for both high [Johnson et al., 1997] and low [Gong et al., 1996] bone mass to chromosome 11q and osteopetrosis to chromosome 1p [

Topics: Animals; Apolipoproteins E; Bone Density; Chromosome Mapping; Collagen; Female; Fractures, Bone; Genetic Predisposition to Disease; Humans; Interleukin-6; Male; Mice; Osteoporosis; Receptors, Calcitriol; Receptors, Estrogen; Risk Factors; Transforming Growth Factor beta

Topics: Animals; Bone and Bones; Bone Resorption; Cell Differentiation; Cytokines; Estrogen Receptor alpha; Estrogen Receptor beta; Estrogens; Female; Glycoproteins; Growth Substances; Humans; Insulin-Like Growth Factor I; Male; Osteoblasts; Osteoporosis; Osteoprotegerin; Receptors, Cytoplasmic and Nuclear; Receptors, Estrogen; Receptors, Tumor Necrosis Factor; Steroids; Transforming Growth Factor beta

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

Topics: Animals; Bone and Bones; Bone Demineralization, Pathologic; Calcium; Hindlimb Suspension; Humans; Insulin-Like Growth Factor I; Osteoblasts; Osteoporosis; Rats; Space Flight; Transforming Growth Factor beta; Weightlessness

The cellular mechanisms involved in osteoblast function and bone formation alterations in osteoporosis have been partly elucidated. Recent studies have shown that bone formation abnormalities in various forms of osteopenia result mainly from defective recruitment of osteoblastic cells. These abnormalities in osteoblast function and bone formation are associated with alterations in the expression or production of several growth factors, such as IGFs and TGF-beta, which modulate the proliferation and activity of bone-forming cells. Bone loss related to aging or unloading is characterized by diminished osteoblast proliferation and reduced local concentrations of IGFs and TGF beta. In contrast, estrogen deficiency increases osteoblast proliferation and IGF-I production. These data suggest that alterations in the production of and/or in cell responsiveness to local growth factors may contribute to the bone formation abnormalities seen in these osteopenic disorders. This suggests that preventive or curative treatment with growth factors may be beneficial in osteopenia due predominantly to decreased bone formation. Low doses of IGF-I or TGF-beta have been reported to increase osteoblast recruitment and differentiation, leading to enhanced trabecular bone formation and decreased bone loss in models of osteopenia induced by aging, estrogen deficiency and unloading. A few clinical trials also suggest that low doses of growth factors may stimulate bone formation. Although these findings open up new prospects for the prevention and treatment of osteopenic disorders, progress in this direction awaits the development of factors or analogs that are capable of locally and specifically increasing osteoblast recruitment and differentiation without including side-effects.

Topics: Aged; Aging; Animals; Clinical Trials as Topic; Estrogens; Female; Humans; Insulin-Like Growth Factor I; Male; Osteoblasts; Osteoporosis; Osteoporosis, Postmenopausal; Prognosis; Stress, Mechanical; Transforming Growth Factor beta

Both insulin-like growth factor-I (IGF-I) and transforming growth factor beta (TGF beta) have powerful modulatory effects in a variety of tissues. A major target of action is the skeletal system, where they enhance bone formation and decrease matrix degradation, thus playing a part in the maintenance of bone mass. Because of the potent mitogenic effect of these agents on osteoblasts, recombinant IGF-I (rhIGF-I) and recombinant TGF beta (rhTGF beta) have potential as drugs to stimulate bone formation in the prevention and treatment of osteoporosis. Using biochemical markers, subcutaneous rhIGF-I therapy has been shown to increase bone turnover and bone formation in nonosteoporotic older people. However, a corresponding increase in bone mass has not yet been documented nor have there been reports yet on the effects of systemically administered rhTGF beta in humans. Further investigation is required to define the clinical potential of rhIGF-I and rhTGF beta as therapeutic agents in age-related osteoporosis.

Topics: Age Factors; Humans; Insulin-Like Growth Factor I; Osteoporosis; Recombinant Proteins; Transforming Growth Factor beta

An ideal therapeutic agent for osteoporosis-one that both inhibits osteoclastic bone resorption and stimulates new bone formation-is not currently available. Currently available resorption inhibitors (estrogen, bisphosphonates, and calcitonin) prevent further bone loss and stabilize bone mass. However, they have a negligible to very modest effect on bone formation over prolonged periods, and do not cause prolonged increases in bone mass. A universally acceptable bone formation stimulator is not currently available. Future research is likely to focus on the use of peptide growth factors to stimulate appositional bone growth, or on the use of low molecular weight compounds that may selectively stimulate bone cells to produce these factors in the local bone remodeling microenvironment.

Topics: Bone Development; Bone Morphogenetic Proteins; Bone Resorption; Fluorides; Forecasting; Humans; Osteoporosis; Proteins; Research; Somatomedins; Transforming Growth Factor beta

Human bone contains an abundance of polypeptide growth factors. These growth factors stimulate the proliferation and activity of bone cells and can stimulate bone formation. Data from this laboratory and others suggest that bone growth factors may act to couple bone formation to resorption to maintain bone mass during remodeling. Research is underway to study these growth factors in bones and teeth, and their possible roles in both the pathogenesis and the treatments of osteoporosis and dental diseases.

Topics: Animals; Bone and Bones; Bone Remodeling; Dentin; Estrogens; Growth Disorders; Growth Substances; Humans; Odontoblasts; Odontogenesis; Osteoarthritis; Osteogenesis; Osteoporosis; Periodontal Diseases; Somatomedins; Tooth; Transforming Growth Factor beta; Vitamin D Deficiency

Glucocorticoid-induced osteoporosis is the third epidemic osteoporosis following postmenopausal and senileosteoporosis. According to one study, salidroside made ovariectomized rats' bones strong. Salidroside's potential for treating glucocorticoid-induced osteoporosis remains unproven. This study aimed to investigate the protective effect and mechanism of salidroside on dexamethasone-induced osteogenic differentiation and bone formation in MC3T3-E1 cells and zebrafish. The study proved that salindroside had no harmful impact on MC3T3E1 cells. Salidroside significantly relieved dexamethasone-induced inhibition of ALP (alkaline phosphatase) activity and mineralization in MC3T3-E1 cells, and promoted osteogenic differentiation of cells. Salidroside increased the expression of osteopontin (OPN), runt-related transcription factor 2 (Runx2), osterix (Osx), transforming growth factor-beta (TGF-β) proteins and promoted the phosphorylation of Smad2/3 in MC3T3-E1 cells treated with dexamethasone. In addition, the effect of salidroside in relieving dexamethasone-induced inhibition of osteogenic differentiation in MC3T3-E1 cells can be blocked by TGF-β receptor type I/II inhibitor (LY2109761). At the same time, we found that salidroside significantly alleviated the inhibition of dexamethasone-induced bone formation in zebrafish and promoted the mineralization of zebrafish skulls. LY2109761 reversed the protective impact of salidroside on dexamethasone-mediated bone impairment in zebrafish. These findings suggested that salidroside alleviated dexamethasone-induced inhibition of osteogenic differentiation and bone formation via TGF-β/Smad2/3 signaling pathway.

Topics: Animals; Dexamethasone; Glucocorticoids; Osteoblasts; Osteogenesis; Osteoporosis; Rats; Signal Transduction; Smad2 Protein; Transforming Growth Factor beta; Transforming Growth Factors; Zebrafish; Zebrafish Proteins

TGFβ1 induces age-related bone loss by promoting degradation of TNF receptor-associated factor 3 (TRAF3), levels of which decrease in murine and human bone during aging. We report that a subset of neutrophils (TGFβ1

Topics: Animals; Bone Marrow; Male; Maraviroc; Mice; Neutrophils; Osteoporosis; Receptors, CCR5; TNF Receptor-Associated Factor 3; Transforming Growth Factor beta

Bone loss is one of the most common complications of immobilization after spinal cord injury (SCI). Whether transforming growth factor (TGF)-β signaling plays a role in SCI-induced disuse bone loss has not been determined. Thus, 16-week-old male mice underwent sham or spinal cord contusion injury to cause complete hindlimb paralysis. Five days later, 10 mg/kg/day control (IgG) or anti-TGF-β1,2,3 neutralizing antibody (1D11) was administered twice weekly for 4 weeks. Femurs were examined by micro-computed tomography (micro-CT) scanning and histology. Bone marrow (BM) supernatants were analyzed by enzyme-linked immunosorbent assay for levels of procollagen type 1 intact N-terminal propeptide (P1NP), tartrate-resistant acid phosphatase (TRAcP-5b), receptor activator of nuclear factor-kappa B ligand (RANKL), osteoprotegerin (OPG), and prostaglandin E2 (PGE2). Distal femoral micro-CT analysis showed that SCI-1D11 mice had significantly (P < .05) attenuated loss of trabecular fractional bone volume (123% SCI-1D11 vs 69% SCI-IgG), thickness (98% vs 81%), and connectivity (112% vs 69%) and improved the structure model index (2.1 vs 2.7). Histomorphometry analysis revealed that osteoclast numbers were lower in the SCI-IgG mice than in sham-IgG control. Biochemically, SCI-IgG mice had higher levels of P1NP and PGE2 but similar TRAcP-5b and RANKL/OPG ratio to the sham-IgG group. The SCI-1D11 group exhibited higher levels of P1NP but similar TRAcP-5b, RANKL/OPG ratio, and PGE2 to the sham-1D11 group. Furthermore, 1D11 treatment prevented SCI-induced hyperphosphorylation of tau protein in osteocytes, an event that destabilizes the cytoskeleton. Together, inhibition of TGF-β signaling after SCI protects trabecular bone integrity, likely by balancing bone remodeling, inhibiting PGE2 elevation, and preserving the osteocyte cytoskeleton.

Topics: Animals; Antibodies, Neutralizing; Bone and Bones; Bone Diseases, Metabolic; Bone Marrow; Bone Remodeling; Bone Resorption; Cancellous Bone; Cytoskeleton; Dinoprostone; Disease Models, Animal; Homeostasis; Male; Mice; Mice, Inbred C57BL; Osteocytes; Osteoporosis; Osteoprotegerin; Peptides; Phosphorylation; RANK Ligand; Signal Transduction; Smad2 Protein; Spinal Cord Injuries; Transforming Growth Factor beta; X-Ray Microtomography

Osteoporosis is a bone‑related disease that results from impaired bone formation and excessive bone resorption. The potential value of adipokines has been investigated previously, due to their influence on osteogenesis. However, the osteogenic effects induced by omentin‑1 remain unclear. The aim of the present study was to determine the regulatory effects of omentin‑1 on osteoblast viability and differentiation, as well as to explore the underlying molecular mechanism. The present study investigated the effects of omentin‑1 on the viability and differentiation of mouse pre‑osteoblast cells (MC3T3‑E1) using quantitative and qualitative measures. A Cell Counting Kit‑8 assay was used to assess the viability of MC3T3‑E1 cells following treatment with different doses of omentin‑1. Omentin‑1 and bone morphogenetic protein (BMP) inhibitor were added to osteogenic induction mediums in different ways to assess their effect. The alkaline phosphatase (ALP) activity and Alizarin Red S (ARS) staining of MC3T3‑E1 cells treated with omentin‑1 and/or BMP inhibitor were used to examine the effects of omentin‑1 on differentiation and mineralization. Western blotting was used to further explore its potential mechanism, and to study the role of omentin‑1 on the viability and differentiation of osteoblasts. The results showed that omentin‑1 altered the viability of MC3T3‑E1 cells in a dose‑dependent manner. Omentin‑1 treatment significantly increased the expression of members of the TGF‑β/Smad signaling pathway. In the omentin‑1 group, the ALP activity of the MC3T3‑E1 cells was increased, and the ARS staining area was also increased. The mRNA and protein expression levels of BMP2, Runt‑related transcription factor 2, collagen1, osteopontin, osteocalcin and osterix in the omentin‑1 group were also significantly upregulated. All these effects were reversed following treatment with SIS3 HCl. These results demonstrated that omentin‑1 can significantly promote osteoblast viability and differentiation via the TGF‑β/Smad signaling pathway, thereby promoting bone formation and preventing osteoporosis.

Topics: Animals; Bone Morphogenetic Protein 2; Cell Differentiation; Mice; Osteoblasts; Osteogenesis; Osteoporosis; Signal Transduction; Transforming Growth Factor beta

We hypothesis that Rho kinase inhibitor fasudil ameliorates osteoporosis following myocardial infarction (MI) by regulating cardiac calcitonin secretion. A mice model of MI and cultured neonatal cardiomyocytes exposed to hypoxia and serum deprivation (H/SD), and fibroblasts exposed to TGF-β were used, respectively. Cardiac function in vivo was assessed with echocardiography. Osteoporosis in vivo was assessed with X-ray and micro-CT. In vivo and in vitro studies used histological and immunohistochemical techniques, along with western blots. In mice post-MI, fasudil ameliorates the microstructure and bone metabolism of the lumbar, improved cardiac function, and attenuated myocardial fibrosis. In vitro, fasudil or αCGRP could effectively inhibit the proliferation of primary fibroblasts treated with TGF-β. Moreover, fasudil ameliorates the cardiac calcitonin secretion induced by MI in vivo or by H/SD in vitro. Our findings suggest that fasudil improved MI-induced osteoporosis by promoting cardiac secreting calcitonin.

Topics: Animals; Calcitonin; Fibrosis; Mice; Myocardial Infarction; Myocardium; Myocytes, Cardiac; Osteoporosis; Transforming Growth Factor beta

Bone homeostasis is the equilibrium between organic and inorganic components of the extracellular matrix (ECM) and cells. Alteration of this balance has consequences on bone mass and architecture, resulting in conditions such as osteoporosis (OP). Given ECM protein mutual regulation and their effects on bone structure and mineralization, further insight into their expression is crucial to understanding bone biology under normal and pathological conditions. This study focused on Type I Collagen, which is mainly responsible for structural properties and mineralization of bone, and selected proteins implicated in matrix composition, mineral deposition, and cell-matrix interaction such as Decorin, Osteocalcin, Osteopontin, Bone Sialoprotein 2, Osteonectin and Transforming Growth Factor beta. We developed a novel multidisciplinary approach in order to assess bone matrix in healthy and OP conditions more comprehensively by exploiting the Fourier Transform Infrared Imaging (FTIRI) technique combined with histomorphometry, Sirius Red staining, immunohistochemistry, and Western Blotting. This innovatory procedure allowed for the analysis of superimposed tissue sections and revealed that the alterations in OP bone tissue architecture were associated with warped Type I Collagen structure and deposition but not with changes in the total protein amount. The detected changes in the expression and/or cooperative or antagonist role of Decorin, Osteocalcin, Osteopontin, and Bone Sialoprotein-2 indicate the deep impact of these NCPs on collagen features of OP bone. Overall, our strategy may represent a starting point for designing targeted clinical strategies aimed at bone mass preservation and sustain the FTIRI translational capability as upcoming support for traditional diagnostic methods.

Topics: Collagen; Collagen Type I; Decorin; Femur Head; Fourier Analysis; Humans; Integrin-Binding Sialoprotein; Osteocalcin; Osteonectin; Osteopontin; Osteoporosis; Transforming Growth Factor beta

NADPH oxidase 4 (Nox4) is the main source of reactive oxygen species, which promote osteoclast formation and lead to bone loss, thereby causing osteoporosis. However, the role of Nox4 in osteoblasts during early development remains unclear. We used zebrafish to study the effect of Nox4 deletion on bone mineralization in early development. nox4

Topics: Animals; Humans; NADPH Oxidase 4; Osteoblasts; Osteoporosis; Signal Transduction; Transforming Growth Factor beta; Zebrafish

TGF-β superfamily signaling is indispensable for bone homeostasis. However, the global expression profiles of all the genes that make up this signaling module in bone and bone-related diseases have not yet been well characterized.. Transcriptomic datasets from human bone marrows, bone marrow-derived mesenchymal stem cells (MSCs) and MSCs of primary osteoporotic patients were used for expression profile analyses. Protein treatments, gene quantification, reporter assay and signaling dissection in MSC lines were used to clarify the interactive regulations and feedback mechanisms between TGF-β superfamily ligands and antagonists. Ingenuity Pathway Analysis was used for network construction.. We identified TGFB1 in the ligand group that carries out SMAD2/3 signaling and BMP8A, BMP8B and BMP2 in the ligand group that conducts SMAD1/5/8 signaling have relatively high expression levels in normal bone marrows and MSCs. Among 16 antagonist genes, the dominantly expressed TGF-β superfamily ligands induced only NOG, GREM1 and GREM2 via different SMAD pathways in MSCs. These induced antagonist proteins further showed distinct antagonisms to the treated ligands and thus would make up complicated negative feedback networks in bone. We further identified TGF-β superfamily signaling is enriched in MSCs of primary osteoporosis. Enhanced expression of the genes mediating TGF-β-mediated SMAD3 signaling and the genes encoding TGF-β superfamily antagonists served as significant features to osteoporosis.. Our data for the first time unveiled the transcription landscape of all the genes that make up TGF-β superfamily signaling module in bone. The feedback mechanisms and regulatory network prediction of antagonists provided novel hints to treat osteoporosis. Video Abstract.

Topics: Bone and Bones; Feedback; Humans; Ligands; Osteoporosis; Transcriptome; Transforming Growth Factor beta

Osteoporosis is characterized by increased bone fragility, and the drugs used at present to treat osteoporosis can cause adverse reactions. Gentiopicroside (GEN), a class of natural compounds with numerous biological activities such as anti-resorptive properties and protective effects against bone loss. Therefore, the aim of this work was to explore the effect of GEN on bone mesenchymal stem cells (BMSCs) osteogenesis for a potential osteoporosis therapy. In vitro, BMSCs were exposed to GEN at different doses for 2 weeks, whereas in vivo, ovariectomized osteoporosis was established in mice and the therapeutic effect of GEN was evaluated for 3 months. Our results in vitro showed that GEN promoted the activity of alkaline phosphatase, increased the calcified nodules in BMSCs and up-regulated the osteogenic factors (Runx2, OSX, OCN, OPN and BMP2). In vivo, GEN promoted the expression of Runx2, OCN and BMP2, increased the level of osteogenic parameters, and accelerated the osteogenesis of BMSCs by activating the BMP pathway and Wnt/β-catenin pathway, effect that was inhibited using the BMP inhibitor Noggin and Wnt/β-catenin inhibitor DKK1. Silencing the β-catenin gene and BMP2 gene blocked the osteogenic differentiation induced by GEN in BMSCs. This block was also observed when only β-catenin was silenced, although the knockout of BMP2 did not affect β-catenin expression induced by GEN. Therefore, GEN promotes BMSC osteogenesis by regulating β-catenin-BMP signalling, providing a novel strategy in the treatment of osteoporosis.

Topics: Animals; beta Catenin; Bone and Bones; Bone Morphogenetic Protein 2; Cell Differentiation; Cells, Cultured; Female; Iridoid Glucosides; Mesenchymal Stem Cells; Mice; Mice, Inbred C57BL; Osteogenesis; Osteoporosis; Recombinant Proteins; Signal Transduction; Transforming Growth Factor beta; Up-Regulation; Wnt Signaling Pathway

Hip fractures are among the most common types of fracture risks in old age osteoporotic patients that often end up with immobile disabilities. Weak bones due to loss of mineral content along with an increase in the porosity of the femur neck canal in osteoporosis reduce the mechanical properties of the bone and predispose the patients to fractures. In this study, we have used calcium sulfate/nanohydroxyapatite based nanocement (NC) as carrier of recombinant human bone morphogenetic protein-2 (BMP-2), zoledronate (ZA), and bone marrow mesenchymal stromal cells (MSCs) derived exosomes (EXO) to enhance bone formation and defect healing in a femur neck canal defect model in osteoporotic rats. A cylindrical defect in the femur neck canal with dimensions of 1 mm (diameter) × 8 mm (length) starting from the lateral cortex toward the apex of the femur head was developed. The defect was impacted using NC alone or functionalized as (a) NC + ZA (systemic), (b) NC + ZA (local), (c) NC + EXO + ZA, and (d) NC + BMP + ZA to evaluate bone formation by ex vivo micro-computed tomography (micro-CT) and histological analysis 16 weeks postsurgery. Moreover, the femurs (both defect and contralateral leg) were subjected to biomechanical analysis to assess the effect of treatments on compressive mechanical properties of the bones. The treatment groups (NC + ZA (L), NC + BMP + ZA, and NC + EXO + ZA) showed enhanced bone formation with complete healing of the defect. No differences in the mechanical properties of both the defect and contralateral across the leg were observed among the groups. However, a trend was observed where NC + BMP + ZA showed enhanced biomechanical strength in the defect leg. This suggests that NC could act as a potent carrier of bioactive molecules to reduce the risks of hip fractures in osteoporotic animals. This type of treatment can be given to patients who are at higher risk of osteoporosis mediated femur neck fracture as a preventive measure or for enhanced healing in already compromised situations. Moreover, this study provided a proof of concept regarding the use of exosomes in bone regeneration therapy, which might be used as a booster dose that will eventually reduce the dosage of BMP and hence circumvent the limitations associated with the use of BMP.

Topics: Animals; Bone Density Conservation Agents; Bone Morphogenetic Protein 2; Bone Regeneration; Bone Resorption; Calcium Sulfate; Drug Carriers; Exosomes; Female; Femur Neck; Hip Fractures; Hydroxyapatites; Nanostructures; Osteogenesis; Osteoporosis; Rats, Sprague-Dawley; Recombinant Proteins; Transforming Growth Factor beta; X-Ray Microtomography; Zoledronic Acid

In a rapidly aging society, the number of people suffering from osteoporosis keeps increasing. However, effective prevention strategies for osteoporosis are not yet currently available.. In this study, we examined the ameliorative effects of tranexamic acid on osteoporosis in 24-month-old mice.. During the study period, mice were orally administered tranexamic acid 3 times per week.. Bone mineral density, which is a parameter of osteoporosis, was improved following tranexamic acid administration. In addition, female mice evidenced a stronger phenotypic improvement than male mice. In female mice treated with tranexamic acid, ovary abnormalities were reduced. Furthermore, the levels of transforming growth factor-β, hyaluronic acid, CD44, reactive oxygen species, and apoptosis, as well as the number of infiltrated neutrophils and macrophages in the ovary were lower than those in the control or solvent-administered mice. In addition, 17β-estradiol levels in blood increased when compared with the control or solvent-treated mice. In addition, administration of tranexamic acid to 24-month-old male mice decreased the level of apoptosis in the testis. However, the levels of 17β-estradiol and testosterone in blood increased compared with the control or solvent-administered mice.. The use of tranexamic acid had an ameliorative effect on osteoporosis, possibly by protecting ovaries and testes.

Topics: Administration, Oral; Aging; Animals; Apoptosis; Bone Density; Estradiol; Female; Hyaluronic Acid; Male; Mice; Mice, Inbred ICR; Osteoporosis; Ovariectomy; Ovary; Protective Agents; Reactive Oxygen Species; Testis; Testosterone; Tranexamic Acid; Transforming Growth Factor beta

Osteoporosis (OP) has a high incidence and can be found in multiple age groups. The bone marrow mesenchymal stem cells (BMSCs) have the potential for self-renewal and multi-directional differentiation, which are often used for investigating the differentiation function of osteoporosis bone marrow mesenchymal stem cells. γ-glutamyl carboxylase (GGCX) is a carboxylase-related carboxylase and was observed to be abnormally expressed in osteoarthritis. However, the role and related mechanisms of GGCX in OP have not been fully elucidated. This work aimed to evaluate the effect of GGCX on the differentiation function of BMSCs.. Sprague-Dawley rats were randomly divided into the OP group prepared by ovariectomy and sham group. GGCX expression was tested by enzyme-linked immunosorbent assay (ELISA). BMSCs were isolated from OP rats and transfected with pcDNA-GGCX plasmids. BMSC proliferation was detected by tetrazolium salt colorimetry (MTT) assay. The osteogenic and adipogenic differentiation of BMSCs was analyzed by alizarin red staining and oil red O staining. The ALP activity was determined by alkaline phosphatase (ALP) activity colorimetric assay. Real time-PCR was used to test the expressions of osteogenesis-related genes RUNX2 and OPN mRNA. Western blot was adopted to assess the TGFβ/smad signaling pathway activity.. GGCX expression was significantly decreased in the serum of OP rats compared with the sham group (p < 0.05). The transfection of pcDNA-GGCX plasmid significantly promoted BMSC cell proliferation, increased calcified nodule formation, inhibited adipogenic differentiation, enhanced ALP activity, elevated RUNX2, and OPN mRNA expressions, and upregulated TGFβ1, Smad2, and Smad7 expressions (p < 0.05).. GGCX secretion is reduced in osteoporosis. GGCX can regulate osteoporosis via promoting the TGFβ/smad signaling pathway, facilitating BMSCs osteogenic differentiation, and inhibiting BMSCs adipogenic differentiation.

Topics: Animals; Carbon-Carbon Ligases; Carboxy-Lyases; Cell Differentiation; Cell Proliferation; Cells, Cultured; Disease Models, Animal; Down-Regulation; Female; Mesenchymal Stem Cells; Osteoporosis; Rats; Rats, Sprague-Dawley; Signal Transduction; Smad Proteins; Transforming Growth Factor beta

The aim of this study is to investigate the effects of recombinant human bone morphogenetic protein-2 (rhBMP-2) on bone-implant osteointegration in osteoporotic rats.. Thirty-six female Wistar rats were randomly divided into 3 groups: sham-operation (SHAM), ovariectomized (OVX), and ovariectomized with rhBMP-2 (OVX + rhBMP-2). The bone density of right tibia was observed with x-ray and the serum alkaline phosphatase (ALP) activity was measured preovariectomy and postovariectomy using an ALP-kit. In OVX + rhBMP-2 group, rhBMP-2 was embedded in the peri-implant area, while SHAM and OVX groups did not contain rhBMP-2. Four and eight weeks after implantation, the rats were killed and the right tibia with implants was taken by x-ray. Histologic changes were investigated by hematoxylin and eosin staining, scanning electron microscope (SEM), and energy dispersive spectrometer examinations.. The serum ALP level was significantly higher in ovariectomized rats compared with that before ovariectomy (P < 0.05), while no difference was found in SHAM rats. At 12 weeks after ovariectomy, radiographic and histologic findings showed significant osteoporotic changes in proximal tibial metaphyses of OVX rats, including reduced cortical bone density and enlargement of bone marrow cavity compared with SHAM ones. The results of implantation verified new bone formation around implants in OVX + rhBMP-2 and SHAM groups, indicating favorable bone healing and osseointegration. No bone resorption was found in OVX + rhBMP-2 group, while some soft tissue was observed in bone-implant interface in SHAM group. In OVX group, there was no effective bone-implant osseointegration and mature bone formed around implants, and some implants were even lost due to chronic inflammation. The percentage of calcium and phosphorous atoms was significantly higher and the percentage of sulfur element was significantly lower in peri-implant area in OVX + rhBMP-2 and SHAM groups than that in OVX group.. rhBMP-2 could enhance the osseous healing and restore bone-implant osseointegration in osteoporotic rats.

Topics: Animals; Bone Density; Bone Density Conservation Agents; Bone Morphogenetic Protein 2; Bone-Anchored Prosthesis; Bone-Implant Interface; Disease Models, Animal; Female; Osseointegration; Osteoporosis; Ovariectomy; Rats; Rats, Wistar; Recombinant Proteins; Tibia; Titanium; Transforming Growth Factor beta

To investigate whether MOTS-c can regulate the synthesis of type I collagen in osteoblasts by regulating TGF-β/SMAD pathway, thereby improving osteoporosis.. Viability of hFOB1.19 cells treated with MOTS-c was detected by CCK-8 assay. The mRNA and protein levels of TGF-β, SMAD7, COL1A1 and COL1A2 in hFOB1.19 cells were detected by quantitative Real-time polymerase chain reaction (qRT-PCR) and Western blot, respectively. We then changed expressions of TGF-β and SMAD7 by plasmids transfection to detect levels of COL1A1 and COL1A2 in hFOB1.19 cells by qRT-PCR and Western blot, respectively.. Cell viability was significantly increased after treatment of 1.0 μM MOTS-c for 24 h or 0.5 μM MOTS-c for 48 h in a time-dependent manner. The mRNA and protein expressions of TGF-β, SMAD7, COL1A1 and COL1A2 in hFOB1.19 cells were dependent on the concentration of MOTS-c. In addition, MOTS-c increased the expressions of COL1A1 and COL1A2, which were partially reversed by knockdown of TGF-β or SMAD7.. MOTS-c could promote osteoblasts to synthesize type I collagen via TGF-β/SMAD pathway.

Topics: Cell Line; Collagen Type I; Humans; Mitochondrial Proteins; Osteoblasts; Osteoporosis; Signal Transduction; Smad Proteins; Transcription, Genetic; Transforming Growth Factor beta

Inflammaging induces osteoporosis by promoting bone destruction and inhibiting bone formation. TRAF3 limits bone destruction by inhibiting RANKL-induced NF-κB signaling in osteoclast precursors. However, the role of TRAF3 in mesenchymal progenitor cells (MPCs) is unknown. Mice with TRAF3 deleted in MPCs develop early onset osteoporosis due to reduced bone formation and enhanced bone destruction. In young mice TRAF3 prevents β-catenin degradation in MPCs and maintains osteoblast formation. However, TRAF3 protein levels decrease in murine and human bone samples during aging when TGFβ1 is released from resorbing bone. TGFβ1 induces degradation of TRAF3 in murine MPCs and inhibits osteoblast formation through GSK-3β-mediated degradation of β-catenin. Thus, TRAF3 positively regulates MPC differentiation into osteoblasts. TRAF3 deletion in MPCs activated NF-κB RelA and RelB to promote RANKL expression and enhance bone destruction. We conclude that pharmacologic stabilization of TRAF3 during aging could treat/prevent age-related osteoporosis by inhibiting bone destruction and promoting bone formation.

Topics: Aging; Animals; Cell Differentiation; Female; Male; Mesenchymal Stem Cells; Mice; Mice, Inbred C57BL; Mice, Knockout; Osteoblasts; Osteoporosis; TNF Receptor-Associated Factor 3; Transforming Growth Factor beta

The current study was to evaluate the protective effects of Chinese medicine prescription Zuogui Pill (ZGP) on osteoporosis (OP) in zebrafish larvae induced by dexamethasone. Alizarin Red staining, calcium and phosphorus determination were performed to evaluate the effect of ZGP on bone mineralization. Hydroxyproline (HP), Alkaline phosphatase (ALP), and tartrate resistant acid phosphatase (TRAP) were also measured by commercial kits. We found that ZGP had positive effects in increasing bone mineral content (BMC), strengthening bone biomechanical, promoting bone formation, inhibiting bone resorption, and mediating protein levels of TGF-β1/Smads signaling pathway. The findings demonstrated that ZGP treatments inhibited the phosphorylation of TGF-β and p-Smad 3 as well as the expressions of collagen I and collagen II by western blot. Taken together, we demonstrated that ZGP may prevent osteoporosis via reversing the imbalance of bone fomation/bone resorption and activating the TGF-β-Smad signal.

Topics: Animals; Blotting, Western; Bone Density; Calcification, Physiologic; Collagen Type I; Collagen Type II; Dexamethasone; Disease Progression; Drugs, Chinese Herbal; Larva; Osteoporosis; Phosphorylation; Signal Transduction; Smad Proteins; Transforming Growth Factor beta; Transforming Growth Factor beta1; Zebrafish

Osteoporosis (OP) is a serious metabolic disease that, due to the increased number or function of osteoclasts, results in increased bone brittleness and, therefore, fragile fracture. Some recent studies report the importance of the transforming growth factor β (TGFβ) pathway in bone homeostasis. RepSox is a small molecule inhibitor of TGFβRI that has a wide range of potential application in clinical medicine, except OP. The aim of our study is to evaluate the effects of RepSox on the differentiation and bone resorption of osteoclasts in vitro and in vivo in an ovariectomy (OVX)-induced OP model. An initial analysis showed TGFβRI messenger RNA expression in both bone samples and bone cells. In the in vitro study, RepSox inhibited the receptor activator of nuclear factor κB ligand (RANKL)-induced osteoclast differentiation and bone resorption activity. Real-time polymerase chain reaction (PCR) analysis showed that RepSox suppressed osteoclastic marker gene expression in both dose-dependent and time-dependent manners. In addition, RepSox did not affect osteoblast differentiation, migration or osteoblastic-specific gene expression in vitro. Furthermore, western blot analysis indicated the underlying mechanisms of the RepSox suppression of osteoclastogenesis via the Smad3 and c-Jun N-terminal kinase/activator protein-1 (JNK/AP-1) signaling pathways. Finally, our animal experiments revealed that RepSox prevented OVX-induced bone loss in vivo. Together, our data suggest that RepSox regulates osteoclast differentiation, bone resorption, and OVX-induced OP via the suppression of the Smad3 and JNK/AP-1 pathways.

Topics: Animals; Bone Resorption; Cell Differentiation; Humans; JNK Mitogen-Activated Protein Kinases; Mice; Osteoclasts; Osteoporosis; Ovariectomy; Pyrazoles; Pyridines; RANK Ligand; Smad3 Protein; Small Molecule Libraries; Transcription Factor AP-1; Transforming Growth Factor beta

To explore whether MOTS-c could improve osteoporosis by promoting osteogenic differentiation of rat bone mesenchymal stem cells (BMSCs) via transforming growth factor-β (TGF-β)/Smad pathway.. Rat BMSCs were isolated and cultured, followed by osteogenic and lipid differentiation. CCK-8 (cell counting kit-8) assay was performed to detect the highest treatment dose of MOTS-c that did not affect cell proliferation. Expressions of osteogenesis-related genes (ALP, Bglap, and Runx2) were detected by qRT-PCR (quantitative Real-Time Polymerase Chain Reaction) and Western blot, respectively. Alizarin red staining and alkaline phosphatase (ALP) cytochemical staining were carried out to evaluate the effect of MOTS-c on BMSCs osteogenesis. TGF-β/Smad pathway-related genes (TGF-β1, TGF-β2, and Smad7) in BMSCs treated with MOTS-c were detected. Finally, TGF-β1 was knocked down to investigate the regulatory effect of MOTS-c on BMSCs osteogenesis.. BMSCs exhibited an elongated morphology and was identified with a high purity by flow cytometry. After osteogenic differentiation, alizarin red staining and ALP staining were all positive. MOTS-c treatment could remarkably stimulate the formation of calcified nodules in BMSCs. Besides, TGF-β/Smad pathway-related genes were significantly upregulated after BMSCs were treated with MOTS-c. Promoted osteogenesis by MOTS-c treatment was reversed by the TGF-β1 knockdown.. MOTS-c promotes cell differentiation of BMSCs to osteoblasts via TGF-β/Smad pathway.

Topics: Animals; Bone Marrow Cells; Cell Differentiation; Cell Proliferation; Cells, Cultured; Mesenchymal Stem Cells; Mitochondrial Proteins; Osteoblasts; Osteogenesis; Osteoporosis; Rats; Rats, Sprague-Dawley; Transforming Growth Factor beta; Transforming Growth Factor beta1

The canine mandible is useful for studying bone regeneration after dental implant placement. However, it is limited in investigations of peri-implant osteogenesis under osteoporotic conditions due to the insignificant osteoporotic effect of ovariectomy. This study aimed at establishing a local osteoporotic model without ovariectomy by using receptor activator of nuclear factor kappa-B ligand (RANKL) in a canine mandible model. This new model was used to evaluate the effects of injectable β-tricalcium phosphate (TCP) microsphere bone grafts on peri-implant bone regeneration under osteoporotic conditions with combinations of recombinant human bone morphogenetic protein-2 (rhBMP-2). A local osteoporotic canine mandible model was designed by creating a hole in the mandibular alveolar bone, then implanting a collagen sponge soaked with 20, 40, or 60 μg RANKL into the hole, and leaving it for 2 weeks. After the establishment of the dose for maximum osteoporotic bone loss at 40 μg of RANKL, the main surgery was performed. RANKL-soaked collagen sponges were removed, and dental implants were placed with bone grafts in five groups: implant only, TCP, and TCP + rhBMP-2 at 5, 15, and 45 μg. Peri-implant bone generation was determined by radiologic and histologic evaluations at 6 weeks after dental implant placement. On performing micro-computed tomography analysis, the group with TCP + 5 μg rhBMP-2 showed the highest bone volume than the other groups and a 22% increase (p < 0.05) compared with the implant-only group. In the histologic analysis, the TCP-only and TCP + 5 μg BMP-2 groups showed higher bone areas (14% and 16% increase, respectively) and bone-implant contact (12% and 7% increase, respectively) compared with the implant-only group, but there was no significant difference among the groups. In this study, the RANKL-induced local osteoporotic canine mandible model was useful for peri-implant bone regeneration under osteoporotic conditions such as those found in geriatric patients. The injectable β-TCP bone grafts used in this study were effective in peri-implant bone generation under osteoporotic conditions, and their efficiency was enhanced at 5 μg BMP-2 compared with higher concentrations of BMP-2.

Topics: Animals; Bone Morphogenetic Protein 2; Bone Regeneration; Dental Implants; Disease Models, Animal; Dogs; Humans; Imaging, Three-Dimensional; Mandible; Osteoporosis; RANK Ligand; Recombinant Proteins; Transforming Growth Factor beta; X-Ray Microtomography

In postmenopausal women, a decrease in bone mineral density (BMD) at the hip and spine is associated with an increased risk of tooth loss, possibly caused by the loss of the alveolar bone. The present study explored the effect of the ovariectomy (OVX) of mice on the miRNA expression profile of their bones.. Micro-CT and histological analysis were performed on mice following OVX or sham-operation using the right mandibles. The left mandibles were used for microarray and quantitative RT-PCR to explore the change in their miRNA expression profile. The differentially expressed miRNAs (DEmiRs) of the OVX and sham-operated mice were analyzed by constructing the miRNA-mRNA-function complex network. We then also analyzed the different roles of the regulation of miRNAs in the mandible and femur by combining public data from GEO.. OVX could lead to a significant decrease in the BMD in the mandible. A total of 53 DEmiRs including, 18 up-regulated and 35 down-regulated miRNAs, were identified. The analysis of the miRNA-mRNA-pathway complex network suggested that miR-17-5p and miRNA-297a-5p were potential biomarkers in the development of mandibles of OVX mice. A comparison of the analysis data on the mandible and femur showed that the transforming growth factor-β signaling pathway was specifically regulated in the mandible, whereas the Wnt signaling pathway was specifically regulated in the femur. Moreover, miR-17-5p and miR-133a-3p showed different expression tendencies in the mandible and in the femur after OVX.. This study provides an integrated function analysis of miRNA in mandibles after OVX and of miR-17-5p and miR-133a-3p as potential biomarkers. Moreover, the mechanism in mandibles may not be comparable with that in femurs with estrogen deficiency.

Topics: Animals; Bone Density; Disease Models, Animal; Female; Mandible; Mice; Mice, Inbred C57BL; MicroRNAs; Osteoporosis; Ovariectomy; Real-Time Polymerase Chain Reaction; RNA, Messenger; Signal Transduction; Transcriptome; Transforming Growth Factor beta; X-Ray Microtomography

Patients suffering from osteoporosis show an increased number of adipocytes in their bone marrow, concomitant with a reduction in the pool of human mesenchymal stem cells (hMSCs) that are able to differentiate into osteoblasts, thus leading to suppressed osteogenesis.. In order to be able to interfere with this process, we have investigated in-vitro culture conditions whereby adipogenic differentiation of hMSCs is impaired and osteogenic differentiation is promoted. By means of gene expression microarray analysis, we have investigated genes which are potential targets for prevention of fat cell differentiation.. Our data show that BMP2 promotes both adipogenic and osteogenic differentiation of hMSCs, while transforming growth factor beta (TGFβ) inhibits differentiation into both lineages. However, when cells are cultured under adipogenic differentiation conditions, which contain cAMP-enhancing agents such as IBMX of PGE2, TGFβ promotes osteogenic differentiation, while at the same time inhibiting adipogenic differentiation. Gene expression and immunoblot analysis indicated that IBMX-induced suppression of HDAC5 levels plays an important role in the inhibitory effect of TGFβ on osteogenic differentiation. By means of gene expression microarray analysis, we have investigated genes which are downregulated by TGFβ under adipogenic differentiation conditions and may therefore be potential targets for prevention of fat cell differentiation. We thus identified nine genes for which FDA-approved drugs are available. Our results show that drugs directed against the nuclear hormone receptor PPARG, the metalloproteinase ADAMTS5, and the aldo-keto reductase AKR1B10 inhibit adipogenic differentiation in a dose-dependent manner, although in contrast to TGFβ they do not appear to promote osteogenic differentiation.. The approach chosen in this study has resulted in the identification of new targets for inhibition of fat cell differentiation, which may not only be relevant for prevention of osteoporosis, but also of obesity.

Topics: Adipocytes; Adipogenesis; Bone Marrow; Bone Marrow Cells; Cell Differentiation; Cell Lineage; Cells, Cultured; Dinoprostone; Gene Expression; Histone Deacetylases; Humans; Mesenchymal Stem Cells; Osteoblasts; Osteogenesis; Osteoporosis; Transforming Growth Factor beta

Recombinant human bone morphogenetic protein-2 (rhBMP-2) is particularly effective in improving osteogenesis in patients with diminished bone healing capabilities, such as individuals with type 1 diabetes mellitus (T1DM) who have impaired bone healing capabilities and increased risk of developing osteoporosis. This study measured the effects of rhBMP-2 treatment on osteogenesis by observing the dose-dependent effect of localized delivery of rhBMP-2 on biomechanical parameters of bone using a hydroxyapatite/tri-calcium phosphate (HA/TCP) carrier in a T1DM-related osteoporosis animal model.. Two different doses of rhBMP-2 (LD low dose, HD high dose) with a HA/TCP carrier were injected into the femoral intramedullary canal of rats with T1DM-related osteoporosis. Two more diabetic rat groups were injected with saline alone and with HA/TCP carrier alone. Radiographs and micro-computed tomography were utilized for qualitative assessment of bone mineral density (BMD). Biomechanical testing occurred at 4- and 8-week time points; parameters tested included torque to failure, torsional rigidity, shear stress, and shear modulus.. At the 4-week time point, the LD and HD groups both exhibited significantly higher BMD than controls; at the 8-week time point, the HD group exhibited significantly higher BMD than controls. Biomechanical testing revealed dose-dependent, higher trends in all parameters tested at the 4- and 8-week time points, with minimal significant differences.. Groups treated with rhBMP-2 demonstrated improved bone mineral density at both 4 and 8 weeks compared to control saline groups, in addition to strong trends towards improvement of intrinsic and extrinsic biomechanical properties when compared to control groups. Data revealed trends toward dose-dependent increases in peak torque, torsional rigidity, shear stress, and shear modulus 4 weeks after rhBMP-2 treatment.. Not applicable.

Topics: Animals; Biomechanical Phenomena; Bone Density; Bone Morphogenetic Protein 2; Calcium Phosphates; Diabetes Mellitus, Type 1; Disease Models, Animal; Durapatite; Femur; Male; Osteogenesis; Osteoporosis; Rats, Wistar; Recombinant Proteins; Transforming Growth Factor beta; X-Ray Microtomography

Imbalance of T-helper-cell (TH) subsets (TH1/TH2/TH17) and regulatory T cells (Tregs) is suggested to contribute to the pathogenesis of osteoporosis. Broken TH17/Treg balance has been reported contributing to several inflammatory diseases. Although bisphosphonates are well-recognized inhibitors of osteoclastic activity, there is no serious examination of their effect on T cell subset (TH1/TH2/TH17/Treg) balances. Patients were categorized into 20 osteopenic and 20 osteoporotic patients treated with bisphosphonates for 1 year. We studied plasma levels of interleukins 4 (IL-4), IL-6, IL-10, IL-12, IL-17, IL-23, and interferon-gamma (IFN-γ), and transforming growth factor-beta (TGF-β) and their interrelations and correlation with osteoporosis treatment were evaluated. Treated osteoporotic patients have a significant reduction of plasma IL-6 (p < 0.05), IL-17 (p < 0.05), IL-23 (p < 0.05), and IFN-γ (p < 0.05), a significant increase in IL-4 (p < 0.05), IL-10 (p < 0.05), and TGF-β (p < 0.001), and comparable IL-12 levels as compared to controls. In conclusion, the significant reduction of Th17 cell cytokine cascade (IL-6, IL-17, and IL-23) and elevation of Treg cytokine cascade (IL-10 and TGF-β) might be considered as a very important observation about the effect of bisphosphonates on TH17/Treg imbalance in osteoporosis.

Topics: Case-Control Studies; Diphosphonates; Female; Humans; Interferon-gamma; Interleukins; Middle Aged; Osteoporosis; T-Lymphocytes, Regulatory; Th17 Cells; Transforming Growth Factor beta

This study evaluated the effect of the combined treatment of intravenous zoledronic acid (ZA, 0.08 mg/kg) and rhBMP-2 (5 µg) on osteogenesis in a calvarial defect model of ovariectomized SD rats. New bone formation was evaluated 4 or 8 weeks after calvarial defect implantation using micro-CT and histology. Micro-CT results revealed that the rhBMP-2 group showed significantly higher calvarial defect coverage ratio compared with the ZA + rhBMP-2 group at 4 weeks. In addition, bone formation indices were significantly lower in ZA + rhBMP-2 group when compared with the rhBMP-2 group after 4 weeks, which indicates a negative effect of ZA on the initial bone formation and the bone quality. At 8 weeks, the negative effect induced by ZA treatment was alleviated as time passed. Histological examination showed similar results to the micro-CT measurements. In conclusion, although ZA treatment lowered the new bone formation induced by rhBMP-2 initially, as time passed, the negative effect was decreased.

Topics: Animals; Bone Density Conservation Agents; Bone Morphogenetic Protein 2; Bone Remodeling; Diphosphonates; Disease Models, Animal; Female; Humans; Imidazoles; Osteogenesis; Osteoporosis; Ovariectomy; Rats; Rats, Sprague-Dawley; Recombinant Proteins; Skull; Transforming Growth Factor beta; Wound Healing; X-Ray Microtomography; Zoledronic Acid

The aim of the present study was to test the biocompatibility and functionality of orthopaedic bone implants with immobilized oligonucleotides serving as anchor stands for rhBMP-2 and rhVEGF-A conjugated with complementary oligonucleotides in an osteoporotic rat model. Al2O3-blasted acid etched Ti6Al4V implants, carrying oligonucleotide anchor strands and hybridized with rhBMP-2 or rhVEGF-A through complementary 31-mer oligonucleotide stands were inserted into the proximal tibia of ovariectomized rats. At the time of surgery (15 weeks after ovariectomy) microCT analysis showed significantly lower bone mineral density compared to non-ovariectomized animals. Bone-implant contact (BIC) and pullout-force were not negatively affected by non-hybridized anchor strands. Twelve weeks after surgery, a significantly higher pullout force was found for BMP-2 hybridized to the anchor strands compared to non-hybridized anchor strands or native samples, and on histomorphometric analysis BIC was highest in the BMP group. Thus, we could show the biocompatibility and in vivo functionality of this modular, self-organizing system for immobilization and subsequent release of BMP-2 in vivo.

Topics: Alloys; Animals; Biomechanical Phenomena; Bone Density; Bone Morphogenetic Protein 2; Female; Humans; Immobilized Proteins; Implants, Experimental; Microscopy, Electron, Scanning; Oligonucleotides; Orthopedics; Osteoporosis; Rats; Rats, Wistar; Recombinant Proteins; Surface Properties; Tibia; Titanium; Transforming Growth Factor beta; X-Ray Microtomography

The failure of orthopedic implants in osteoporotic patients is attributed to the lack of sufficient bone stock and regenerative capacity but most treatments for osteoporosis fail to address this issue. rhBMP-2 is known to promote bone formation under normal conditions but has not been used clinically in the osteoporotic condition. Osteoporosis was induced in 19 ewes using ovariectomy, low calcium diet, and steroid injection. After induction, the steroid was withdrawn and pellets containing inert carrier with rhBMP-2 in either slow or fast-release formulation were implanted into the lumbar vertebrae of each animal. After 2, 3, and 6 months the spines were harvested and assessed for changes in BMD and histomorphometric indices. BMD did not change after cessation of steroid treatment. After 2 months BV/TV increased in the vicinity of the pellets containing the fast-release rhBMP-2 and was sustained for the duration of the study. Focal voids surrounding all implants, particularly the slow-release formulation, were observed initially but resolved with time. Increased BV/TV adjacent to rhBMP-2 pellets suggests it could be used for localized treatment of osteoporosis. Refinement of the delivery system and supplementary treatments may be necessary to overcome the initial catabolic effects of rhBMP-2.

Topics: Absorptiometry, Photon; Animals; Bone Density; Bone Morphogenetic Protein 2; Calcium; Calcium, Dietary; Delayed-Action Preparations; Disease Models, Animal; Female; Glucocorticoids; Humans; Lumbar Vertebrae; Osteogenesis; Osteoporosis; Ovariectomy; Recombinant Proteins; Sheep; Tomography, X-Ray Computed; Transforming Growth Factor beta

Bisphosphonates are a class of agents used for treating osteoporosis and malignant bone metastases treatment. Osteonecrosis of the jaws is the main complication in a subset of patients receiving these drugs. Based on a growing number of case reports and institutional reviews, bisphosphonate therapy can cause exposed and necrotic bone that is isolated to the jaw. This clinical investigation is aimed at analyzing the clinical effect of recombinant human bone morphogenetic protein type 2 (rhBMP-2) application in patients affected by bisphosphonates-related osteonecrosis of the jaws undergoing surgery for necrotic bone removal.A case review was made of 20 patients. The rhBMP-2 in all the cases reported here was used alone with the collagen carrier without concomitant bone materials. The cases involved osteonecrotic lesions of the upper and lower jaws. A total dose of 4 to 8 mg of rhBMP-2 was delivered to the surgical site in concentrations of 1.5 mg/mL (depending on the size of lesion). Patients were followed up over a period ranging 6 to 12 months.Patients had successful healing of the necrotic area. New bone formation in the surgical area could be clinically evaluated by palpation at the end of 3 to 4 months and confirmed by radiographic examination at the end of 12 months.This study indicated that the use of rhBMP-2 without concomitant bone grafting materials was useful in promoting healing of bisphosphonates-related osteonecrosis of the jaws. The use of growth factors, particularly rhBMP-2, should be considered a therapeutic choice in patients affected by osteonecrosis of the jaws related to bisphosphonate therapy.

Topics: Bone Morphogenetic Protein 2; Combined Modality Therapy; Diphosphonates; Humans; Jaw Diseases; Osteonecrosis; Osteoporosis; Pain Management; Postoperative Complications; Recombinant Proteins; Transforming Growth Factor beta; Treatment Outcome; Wound Healing

The effect of osthol on osteoblasts was investigated in primary osteoblastic cells isolated from newborn Wistar rats. Osthol was supplemented into cultured medium at 10⁻⁷, 10⁻⁶, 10⁻⁵ and 10⁻⁴ mol/l, respectively. No stimulating effect was found on cell proliferation, but 10⁻⁵ mol/l osthol caused a significant increase in alkaline phosphatase (ALP) activity. Osteogenic differentiation markers were examined over a period of time at this concentration, and compared with control cells that were not supplemented with osthol. The results showed that the ALP activity, osteocalcin secretion and calcium deposition level in cells treated with osthol were 1.52, 2.74 and 2.0 times higher, respectively, than in the control cells. Results of ALP histochemical staining and mineralized bone nodule assays both showed that the number and area achieved in osthol-treated cells were 1.53-fold higher than in control cells. The gene expression of the growth and transcription factors basic fibroblast growth factor, insulin-like growth factor I, bone morphogenetic protein 2 (BMP-2), runt-related gene 2 (Runx-2) and osterix, which are associated with bone development, were also investigated. The increase in mRNA expression was 1.94, 1.74, 1.68, 1.83 and 2.31 times, respectively, higher compared to the control. Furthermore, osthol increased the protein expression of p38 mitogen-activated protein kinase (MAPK) and type I collagen. p38MAPK protein and collagen in osthol-treated cells were 1.42 and 1.58 times higher in osthol-treated cells compared to the control. The results of these studies support the conclusion that osthol significantly enhances the osteogenic differentiation of cultured osteoblasts. The results also indicated that osthol could stimulate the osteoblastic differentiation of rat calvarial osteoblast cultures by the BMP-2/p38MAPK/Runx-2/osterix pathway and that osthol may be used as an important compound in the development of new antiosteoporosis drugs.

Topics: Alkaline Phosphatase; Animals; Bone Density Conservation Agents; Bone Morphogenetic Protein 2; Calcification, Physiologic; Calcium Channel Blockers; Cell Differentiation; Cell Proliferation; Cnidium; Collagen; Collagen Type I; Coumarins; Dose-Response Relationship, Drug; Drug Evaluation, Preclinical; Fibroblasts; Fruit; Insulin-Like Growth Factor I; Models, Animal; Osteoblasts; Osteocalcin; Osteoporosis; p38 Mitogen-Activated Protein Kinases; Phytotherapy; Plant Preparations; Rats; Rats, Wistar; Skull; Transforming Growth Factor beta

The central role of bone morphogenetic proteins (BMPs) in the remodelling process of the human skeleton has been identified in numerous experimental and clinical studies. BMPs appear to be key agents in the osteoblastic differentiation of mesenchymal stem cells, and more recent evidence implicates them with the cells of the osteoclastic lineage. BMP-2, BMP-4, BMP-6 and BMP-7 have been studied in the context of osteoporosis and have been associated with its pathophysiological pathways. The theoretical advantages of local or systemic treatment of osteoporotic fractures with BMPs include the potential of inducing a rapid increase in bone strength locally at the fractured area and systemically in the entire skeleton, as well as accelerating the bone-healing period. Animal models of osteoporotic fractures suggested that the induction of new bone by local or systemic use of BMP-7 should be investigated as potential bone augmentation therapy to improve bone quality in symptomatic spinal osteoporosis. As our knowledge expands, new innovations may provide clinicians with advanced biologically-based therapies for the successful treatment of osteoporotic fractures.

Topics: Age Factors; Animals; Bone Density; Bone Morphogenetic Protein 2; Bone Morphogenetic Protein 6; Bone Morphogenetic Proteins; Bone Remodeling; Disease Models, Animal; Female; Fracture Healing; Fractures, Spontaneous; Genetic Therapy; Humans; Male; Mesenchymal Stem Cells; Middle Aged; Osteoporosis; Recombinant Proteins; Transforming Growth Factor beta

The aim of this study was to develop a feasible approach to promote bone healing in osteoporotic rats using autogenous bone tissue-engineering and gene transfection of human bone morphogenetic protein 2 (hBMP-2).. Bone marrow stromal cells (BMSCs) from the left tibia of osteoporotic rats were transfected with the hBMP-2 gene in vitro which was confirmed by immunohistochemistry, in situ hybridization and Western blotting. Autogenous transfected or untransfected BMSCs were seeded on macroporous coral hydroxyapatite (CHA) scaffolds. Each cell-scaffold construct was implanted into a defect site which was created in the ramus of the mandible of osteoporotic rats. Four or eight weeks after implantation in situ hybridization was performed in BMSCs transfected with hBMP-2, X-ray examinations, histological and histomorphological analyses were used to evaluate the effect of tissue-engineered bone on osseous defect repair.. Newly formed bone was observed at the margin of the defect 4 weeks after implantation with BMSCs transfected with BMP-2. Mature bone was observed 8 weeks after treatment. In the control group there was considerably less new bone and some adipose tissue was observed at the defect margins 8 weeks after implantation.. Autogenous cells transfected with hBMP-2 promote bone formation in osteoporotic rats. BMSC-mediated BMP-2 gene therapy used in conjunction with bone tissue engineering may be used to successfully treat bone defects in osteoporotic rats. This method provides a powerful tool for bone regeneration and other tissue engineering.

Topics: Alkaline Phosphatase; Animals; Bone and Bones; Bone Marrow Cells; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Bone Regeneration; Combined Modality Therapy; Durapatite; Female; Gene Expression Regulation; Genetic Therapy; Humans; Implants, Experimental; Osteogenesis; Osteoporosis; Ovariectomy; Radiography; Rats; Rats, Sprague-Dawley; Stromal Cells; Tissue Engineering; Transfection; Transforming Growth Factor beta

To effectively treat osteoporosis and other bone-loss disorders, small compounds that potently induce bone formation are needed. The present study initially attempted to establish a monitoring system that could detect osteogenic differentiation easily, precisely, and noninvasively. For this purpose, we established pre-osteoblastic MC3T3E1 cells stably transfected with the GFP reporter gene driven by a 2.3 kb fragment of rat type I collagen promoter (Col1a1GFP-MC3T3E1). Among these cells, we selected a clone that fluoresced upon osteogenic stimulation by BMP2. The GFP fluorescence intensity corresponded well to the intensity of alkaline phosphatase (ALP) staining and to the level of osteocalcin (Oc) mRNA. Using this system, we screened natural and synthetic compound libraries and thus identified an isoflavone derivative, glabrisoflavone (GI). GI induced ALP staining and Oc mRNA in a dose-dependent manner. The Col1a1GFP-MC3T3E1 system may be useful for identifying novel osteogenic drugs.

Topics: Alkaline Phosphatase; Animals; Biosensing Techniques; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Cell Line; Collagen Type I; Drug Evaluation, Preclinical; Fluorescence; Genes, Reporter; Green Fluorescent Proteins; Isoflavones; Mice; Osteoblasts; Osteocalcin; Osteogenesis; Osteoporosis; Rats; Transforming Growth Factor beta

Myostatin is a recently described negative regulator of skeletal muscle mass. This paper hypothesizes a role for this system in cardiac cachexia and insulin resistance and osteoporosis associated with advanced heart failure.

Topics: Animals; Biomarkers; Body Mass Index; Cachexia; Cross-Sectional Studies; Disease Models, Animal; Heart Failure; Humans; Insulin Resistance; Mice; Myostatin; Osteoporosis; Sensitivity and Specificity; Severity of Illness Index; Transforming Growth Factor beta

Bone morphogenetic protein-2 (BMP2) plays a critical role in osteoblastogenesis and adipogenesis from osteoprogenitor cells. The balance between osteogenic and adipogenic effects is influenced by BMP2 concentration, transcription factors and age. BMP2 single nucleotide polymorphisms (SNPs) may contribute to osteoporosis risk, but the relationship between adiposity and body composition has not been explored. We investigated the relationship between BMP2 polymorphisms and body composition in young and elderly women.. Population-based association study.. Four BMP2 SNPs studied. Total body fat and lean mass measured by DEXA in two cohorts: 'PEAK-25' women aged 25 (+/-0.00) (n=993) and osteoporosis prospective risk assessment (OPRA) women aged 75 (+/-0.00) years (n=1001).. We found no association between BMP2 SNPs and fat or lean mass, however, we observed consistent although non-significant trends. Polymorphisms, rs235767 and Ser37Ala, exerted opposing effects on most parameters of soft tissue and bone mass in both cohorts. This relationship appeared to be age specific with large differences between alleles observed (fat mass; Ser37Ala: 14.3% (PEAK-25), -3.5% (OPRA)). These initial results appear to suggest that alleles exerting a beneficial effect in young women may subsequently contribute to phenotypes associated with osteoporosis risk in elderly women.. While further analyses in other comparative populations are necessary, in this study of almost 2000 women we observed interesting, although non-significant trends, regarding the effects of variation in the BMP2 gene on parameters of body mass. Although the exact nature of the relationship remains uncertain, we suggest that the mechanisms are influenced by age and environmental factors.

Topics: Adipose Tissue; Adult; Age Distribution; Aged; Body Composition; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Female; Genetic Predisposition to Disease; Genetic Variation; Humans; Osteoporosis; Overweight; Phenotype; Polymorphism, Single Nucleotide; Risk Factors; Transforming Growth Factor beta

Endogenous TNFalpha prevents the attainment of maximum achievable peak bone mass in vivo. In vitro, TNFalpha suppresses BMP-2- and TGFbeta-mediated Smad activation through induction of NF-kappaB. Consistently, pharmacological suppression of NF-kappaB augments osteoblast differentiation and mineralization in vitro.. Osteoporosis is a major health threat. Traditional therapeutic strategies have centered on anti-catabolic drugs that block bone resorption. Recently focus has shifted to anabolic agents that actively rebuild lost bone mass. Future strategies may involve elevating peak bone mass to delay osteoporosis development. Recent in vitro studies show that TNFalpha represses osteoblast differentiation and mineralization; however, the mechanisms are poorly understood and the impact of basal TNFalpha concentrations on the acquisition of peak bone mass in vivo is unknown.. We examined peak BMD, bone volume, and bone turnover makers in mice deficient in TNFalpha or its receptors. We further examined the effect of TNFalpha on Smad-induced signaling by TGFbeta and BMP-2 in vitro using a Smad responsive reporter. The effect of TNFalpha-induced NF-kappaB signaling on Smad signaling and on in vitro osteoblast mineralization was examined using specific NF-kappaB inhibitors and activators, and effects of TNFalpha-induced NF-kappaB signaling on BMP-2-induced Runx2 mRNA were examined using RT-PCR.. Mice null for TNFalpha or its p55 receptor had significantly increased peak bone mass, resulting exclusively from elevated bone formation. In vitro, TNFalpha potently suppressed Smad signaling induced by TGFbeta and BMP-2, downregulated BMP-2-mediated Runx2 expression, and inhibited mineralization of osteoblasts. These effects were mimicked by overexpression of NF-kappaB and prevented by pharmacological NF-kappaB suppression.. Our data suggest that TNFalpha and NF-kappaB antagonists may represent novel anabolic agents for the maximization of peak basal bone mass and/or the amelioration of pathological bone loss.

Topics: Animals; Bone Density; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Cell Differentiation; Cell Line; Down-Regulation; Mice; Mice, Knockout; NF-kappa B; Osteoblasts; Osteogenesis; Osteoporosis; Receptors, Tumor Necrosis Factor, Type I; Signal Transduction; Smad Proteins; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha

The bone morphogenetic protein (BMP)2 gene has been genetically linked to osteoporosis and osteoarthritis. We have shown that the 3'-untranslated regions (UTR) of BMP2 genes from mammals to fishes are extraordinarily conserved. This indicates that the BMP2 3'-UTR is under stringent selective pressure. We present evidence that the conserved region is a strong posttranscriptional regulator of BMP2 expression. Polymorphisms in cis-regulatory elements have been proven to influence susceptibility to a growing number of diseases. A common single nucleotide polymorphism (SNP) disrupts a putative posttranscriptional regulatory motif, an AU-rich element, within the BMP2 3'-UTR. The affinity of specific proteins for the rs15705 SNP sequence differs from their affinity for the normal human sequence. More importantly, the in vitro decay rate of RNAs with the SNP is higher than that of RNAs with the normal sequence. Such changes in mRNA:protein interactions may influence the posttranscriptional mechanisms that control BMP2 gene expression. The consequent alterations in BMP2 protein levels may influence the development or physiology of bone or other BMP2-influenced tissues.

Topics: 3' Untranslated Regions; Animals; Animals, Newborn; Bone and Bones; Bone Development; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Conserved Sequence; Gene Expression Regulation; Genes, Reporter; Humans; Mice; Mice, Transgenic; Organ Specificity; Osteoporosis; Polymorphism, Single Nucleotide; Protein Binding; Receptors, Androgen; Regulatory Elements, Transcriptional; RNA; RNA Processing, Post-Transcriptional; RNA Stability; Tissue Distribution; Trans-Activators; Transforming Growth Factor beta; Transgenes; Up-Regulation

Core binding factor alpha1 (Cbfa1) is a member of the runt family of transcription factors, which appears to play a pivotal role in regulating the differentiation of osteoblastic precursors and the activity of mature osteoblasts. Total flavonoids of Herba epimedii (HEF) is a recognized bone anabolic agent, but there is lack of reports on the modulation of Cbfa1 expression by HEF. Here we investigated the effect of HEF on Cbfa1 expression in the bone of ovariectomized (OVX) rats. HEF could increase the expression of Cbfa1 mRNA in the bone of ovariectomized rats in a dose-dependent manner. Furthermore, the high dose HEF (160 mg/kg) administered for 12 weeks in vivo stimulated osteocalcin expression. These findings suggest that Cbfa1 is required for mediating the anabolic effects of HEF.

Topics: Animals; Bone Density; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Cell Differentiation; Core Binding Factor Alpha 1 Subunit; Dose-Response Relationship, Drug; Epimedium; Estradiol; Female; Flavonoids; Gene Expression Regulation; Osteoblasts; Osteocalcin; Osteoporosis; Ovariectomy; Rats; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Skull; Time Factors; Transforming Growth Factor beta

Osteoporosis, a major public health burden, is associated with increased fracture risk. Fracture healing in osteoporosis is delayed, with reduced callus formation and impaired biomechanical properties of newly formed bone leading to high risk of fixation failure. Adenoviral gene transfer of bone morphogenetic protein-2 (BMP-2) has been shown to enhance fracture healing. This study evaluated the ability of gene transfer to enhance bone healing in osteoporosis. An established sheep model of osteoporosis with well-characterized alterations in fracture healing was used. Osteotomies were created surgically in the tibias of adult female sheep and monitored for 8 weeks, using radiographic, biomechanical, and histological methods. For pilot experiments, primary ovine osteoblasts and mesenchymal stem cells were transduced with a recombinant adenovirus carrying BMP-2 cDNA (Ad.BMP-2). Large increases in alkaline phosphatase production and mineralization confirmed the ability of human BMP-2 to stimulate osteoblastic differentiation in sheep. In vivo bending stiffness measurements during fracture healing as well as ex vivo torsional stiffness measurements demonstrated stiffer callus tissue after treatment with Ad.BMP-2. The differences were found mainly in the early fracture-healing period. Computed tomography demonstrated that animals receiving the BMP-2 cDNA had larger cross-sectional callus area and higher callus density. Histological examination of the tibias confirmed enhanced callus formation. Direct, local adenoviral delivery of an osteogenic gene thus led to enhanced healing of fractures in an ovine model of osteoporosis. These promising data encourage the further development of genetic approaches to enhance bone healing in patients suffering osteoporosis-associated fractures.

Topics: Adenoviridae; Animals; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Bony Callus; Cell Differentiation; Cells, Cultured; Female; Fracture Healing; Genetic Therapy; Genetic Vectors; Humans; Osteoblasts; Osteoporosis; Pilot Projects; Pliability; Radiography; Sheep; Tibia; Transduction, Genetic; Transforming Growth Factor beta

After reported associations of variations in the BMP-2 gene with osteoporosis in small populations, we studied the association of the BMP-2 gene polymorphisms Ser37Ala and Arg190Ser with osteoporosis in 6353 men and women from the Rotterdam Study. We did not observe an association of these variants with BMD, bone loss, hip structural analysis parameters, and fracture risk.. Bone morphogenetic protein 2 (BMP-2) plays a role in osteoblast differentiation. BMP-2 gene variation has previously been associated with osteoporosis in various small populations, but current evidence remains inconclusive about the exact association with osteoporosis. Therefore, we studied the association of two polymorphisms located in the BMP-2 gene (Ser37Ala and Arg190Ser) and haplotypes defined by these polymorphisms with BMD, rates of bone loss, parameters of hip structural analysis (HSA), and fractures in the Rotterdam Study, a large prospective cohort study of diseases in the elderly.. Databases were searched for polymorphisms and haplotype blocks in the BMP-2 gene region. Allele frequencies for Ser37Ala and Arg190Ser were determined in 60 blacks and 110 Chinese from Coriell panels. Genotype data on Ser37Ala and Arg190Ser were available for 6353 individuals from the Rotterdam Study population. Haplotype alleles defined by Ser37Ala and Arg190Ser were inferred using PHASE software. Genotype and haplotype analyses for BMD (measured at the lumbar spine and femoral neck), bone loss per year (measured at the femoral neck), and HSA were performed using AN(C)OVA. Fractures were analyzed using a Cox proportional-hazards model and logistic regression. All outcomes were adjusted for age, height, and weight.. Allele frequencies were 2.5% for Ala37 and 40.2% for Ser190, whereas haplotype allele frequencies were 57.28% (Ser37Arg190), 40.19% (Ser37Ser190), 2.50% (Ala37Arg190), and 0.02% (Ala37Ser190). For BMD, bone loss, HSA outcomes, and (incident) fractures, no differences could be seen between genotype and haplotype groups.. In this large population-based cohort of Dutch whites, we conclude that the BMP-2 Ser37Ala and Arg190Ser polymorphisms or haplotypes thereof are not associated with parameters of osteoporosis.

Topics: Aged; Asian People; Black People; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Cohort Studies; Databases as Topic; Female; Gene Frequency; Genetic Variation; Genotype; Haplotypes; Humans; Male; Netherlands; Osteoporosis; Polymorphism, Single Nucleotide; Prospective Studies; Risk Factors; Transforming Growth Factor beta; White People

The aim of this study was to examine whether variants in genes for transforming growth factor beta1 (TGF-beta1; Leu10>Pro and Arg25>Pro), plasminogen activator inhibitor 1 (PAI-1; 4G>5G variant) and collagen 1 (COL1A1; Sp1 variant) may be useful in identifying individuals with increased susceptibility to early postmenopausal bone loss within the population of Czech women.. Polymorphisms were genotyped (by PCR and restriction analysis) in 1400 females representatively selected from the Czech population as well as in 218 postmenopausal osteoporotic women 40-70 years of age (mean age 58,7 years) and a 151 postmenopausal females within the same age range (mean age 59,1 years) with normal BMD.. We have not found any statistically significant differences in the frequency of individual genotypes or alleles of analyzed variants between the groups of osteoporotic patients (OP), population group (PG) and control group (CG). The frequency of the individual genotypes in the analyzed groups was as follows 1) TGF-beta1 gene: Leu10Leu10 OP 30.2 %, PG 35.6 %, CG 35.1 %; Leu10Pro10 OP 52.1 %, PG 47.1 %, CG 50.0 %; Pro10Pro10 OP 17.7 %, PG 17.3 %, CG 14.9 %; 2) TGF-beta1 gene Arg25 homozygotes OP 83.8 %, PG 86.1%, CG 89.3 %, Pro25 carriers OP 16.2 %, PG 13.9 %, CG 10.7 %, 3) PAI-1 gene: 4G4G OP 34.9 %, PG 31.8, CG 28.5 %, 5G4G OP 43.6 %, PG 46.7 %, CG 50.3 %, 5G5G OP 21.5 %, PG 21.5%, CG 21.2%, and 4) COL1A-1 ("SS" homozygotes, OP 63.0%, PG 63.7%, CG 64.6 %, "s" carriers OP 37.0 %, PG 36.3 %, CG 35.1 %).. Variants in genes for TGF-beta1 (Leu10>Pro and Arg25>Pro), PAI-1 (4G>5G) and COL1A1 (Sp1 variant) are not associated with low BMD in postmenopausal Czech Caucasian females.

Topics: Adult; Aged; Bone Density; Collagen Type I; Collagen Type I, alpha 1 Chain; Female; Fractures, Bone; Gene Frequency; Genetic Testing; Genotype; Humans; Middle Aged; Osteoporosis; Plasminogen Activator Inhibitor 1; Polymorphism, Genetic; Transforming Growth Factor beta; White People

We studied the healing process of mandibular closed fractures in osteoporotic rats using specific antibodies to bone morphogenetic protein-2 (BMP-2) and tumour necrosis factor-alpha (TNF-alpha). We confirmed the osteoporosis in rats after oophorectomy by micro-CT, and then caused unilateral closed fractures in the mandible and monitored the healing process after 7, 14, 21, and 28 days. Data were compared simultaneously with those from a group of rats that had a sham operation. During healing of the fracture in the osteoporotic group there was a prolonged phase of endochondral ossification, with an increased number of osteoclasts (p<0.01). Expressions of BMP-2 and TNFalpha were more pronounced in the osteoporotic group and there was an increase in the number of osteoblasts and TNFalpha(+) cells compared with the normal control (p<0.01). BMP-2 was related to the differentiation of osteoblasts and the higher values of TNFalpha were correlated with the up-regulation of osteoclasts during the prolonged phase of bone turnover. We conclude that the healing of fractures in osteoporotic bone is delayed about a week compared with controls. In the healing of fractures in osteoporotic bone, there were more osteoblasts and osteoclasts but there was a predominance of osteoclasts probably induced by TNFalpha. The prolonged phase of bone turnover with osteoclast predominance in the osteoporotic group is suggestive of the cause of delay in the healing of the fracture.

Topics: Animals; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Bony Callus; Female; Fracture Healing; Fractures, Closed; Immunohistochemistry; Mandibular Fractures; Osteoclasts; Osteoporosis; Ovariectomy; Rats; Rats, Wistar; Tomography, X-Ray Computed; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha

The survival of osteoblast cells is one of the determinants of the development of osteoporosis in patients. Osthole (7-methoxy-8-isopentenoxycoumarin) is a coumarin derivative present in many medicinal plants. By means of alkaline phosphatase (ALP) activity, osteocalcin, osteopontin, and type I collagen, enzyme-linked immunosorbent assay, we have shown that osthole exhibits a significant induction of differentiation in two human osteoblast-like cell lines, MG-63 and hFOB. Induction of differentiation by osthole was associated with increased bone morphogenetic protein (BMP)-2 production and the activations of SMAD1/5/8 and p38 and extracellular signal-regulated kinase (ERK) 1/2 kinases. Addition of purified BMP-2 protein did not increase the up-regulation of ALP activity and osteocalcin by osthole, whereas the BMP-2 antagonist noggin blocked both osthole and BMP-2-mediated ALP activity enhancement, indicating that BMP-2 production is required in osthole-mediated osteoblast maturation. Pretreatment of osteoblast cells with noggin abrogated p38 activation but only partially decreased ERK1/2 activation, suggesting that BMP-2 signaling is required in p38 activation and is partially involved in ERK1/2 activation in osthole-treated osteoblast cells. Cotreatment of p38 inhibitor SB203580 [4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)-1H-imidazole] or p38 small interfering RNA (siRNA) expression inhibited osthole-mediated activation of ALP but only slightly affected osteocalcin production. In contrast, the production of osteocalcin induced by osthole was inhibited by the mitogen-activated protein kinase kinase inhibitor PD98059 (2'-amino-3'-methoxyflavone) or by expression of an ERK2 siRNA. These data suggest that BMP-2/p38 pathway links to the early phase, whereas ERK1/2 pathway is associated with the later phase in osthole-mediated differentiation of osteoblast cells. In this study, we demonstrate that osthole is a promising agent for treating osteoporosis.

Topics: Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Cell Differentiation; Cell Proliferation; Cells, Cultured; Coumarins; DNA-Binding Proteins; Humans; MAP Kinase Signaling System; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Osteoblasts; Osteoporosis; p38 Mitogen-Activated Protein Kinases; RNA, Small Interfering; Smad Proteins; Smad1 Protein; Trans-Activators; Transforming Growth Factor beta

To investigate the effects of Benefiting-bone capsule (BBC) on the expression of transforming growth factor-beta1 mRNA in bone tissue of the ovariectomized rats to further explain the mechanism of BBC on preventing and treating osteopoprosis.. Twenty-four rats were randomly chosen from 72 female SD rats aged 10 months, which were classified into group A and B of sham operation dealing with normal physiological saline. The left 48 rats were randomly divided into 4 groups after ovariectomy: group A and B of osteoporotic animal model with normal physiological saline, prevented and treated groups of osteoporotic animal model with BBC. Each group included 12 rats. Ovariectomy was used to establish the osteoporotic animal model and the expression of TGF-beta1 mRNA on gene level in bone tissue was detected by real time fluorescence quantitative PCR (FQ-PCR) method.. The expression of TGF-beta1 mRNA on gene level in bone tissue of the groups of osteoporotic animal model with BBC were all higher than that of the groups of osteoporotic animal model, which were close to the groups of sham operation.. BBC can improve the expression of TGF-beta1 mRNA on gene level in bone tissue, which may be the mechanism of BBC on preventing and treating osteoporosis.

Topics: Animals; Bone and Bones; Capsules; Disease Models, Animal; Drug Combinations; Drugs, Chinese Herbal; Female; Osteoporosis; Ovariectomy; Plants, Medicinal; Polymerase Chain Reaction; Rats; Rats, Sprague-Dawley; RNA, Messenger; Transforming Growth Factor beta; Transforming Growth Factor beta1

Osteointegration of metal implants into aged organisms can be severely compromised due to reduced healing capacity of bone, lack of precursor cells for new bone formation, or osteoporosis. Here, we report on successful implant healing in a novel model of aged sheep in the presence of nonglycosylated bone morphogenetic protein 2 (BMP-2). Ewes of 8 to 12 years with significant radiologic and histologic signs of osteoporosis and adipocytic bone marrow received a cylindrical hydroxyapatite-titanium implant of 12 x 10 mm. BMP-2 has been produced as a bacterial recombinant fusion protein with maltose-binding protein and in vitro generation of mature BMP-2 by renaturation and proteolytic cleavage. A BMP-2 inhibition ELISA was developed to measure the in vitro release kinetics of bioactive human BMP-2 from immersed solid implant materials by using Escherichia coli expressed and biotinylated recombinant human BMP-2 receptor IA extracellular domain (ALK-3 ECD). The implants were placed laterally below both tibial plateaus, with the left leg implant carrying 380 microg BMP-2. Both implant types became integrated within the following 20 weeks. The control implant only integrated at the cortical bone, and little new bone formation was found within the pre-existing trabecular bone or the marrow cavity. Marrow fat tissue was partially replaced by unspecific connective tissue. In contrast, BMP-2-coated implants initiated significant new bone formation, initially in trabecular arrangements to be replaced by cortical-like bone after 20 weeks. The new bone was oriented towards the cylinder. Highly viable bone marrow appeared and filled the lacunar structures of the new bone. In mechanical tests, the BMP-2-coated implants displayed in average 50% higher stability. This animal model provided first evidence that application of nonglycosylated BMP-2 coated on solid implants may foster bone healing and regeneration even in aged-compromised individuals.

Topics: Aging; Animals; Biomechanical Phenomena; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Bone Regeneration; Bone Remodeling; Disease Models, Animal; Female; Glycosylation; Hydroxyapatites; Models, Biological; Osseointegration; Osteogenesis; Osteoporosis; Prostheses and Implants; Recombinant Fusion Proteins; Sheep; Tibia; Titanium; Transforming Growth Factor beta

Data from cell culture experiments suggest that local growth factors (GFs) may mediate the effects of estrogens, calcitonin or fluor ions on the skeleton. To assess the in vivo relevance of the in vitro reports, the effect of fluor salts, hormone replacement therapy (HRT) and calcitonin on the concentrations of IGF-I, IGF-II and transforming growth factor (TGF)-beta 1 in bone matrix extracts from osteoporotic patients was evaluated.. Iliac crest bone biopsies were obtained from 170 patients (76 men and 94 women) with primary osteoporosis aged 55.5+/-0.8 Years.. Bone matrix extraction was performed based on a guanidine-HCl/ethylendiamine-tetra-acetic acid method.. In comparison with age- and body mass index (BMI)-matched controls, no influence of long-term therapy with fluor ions (n=41) or calcitonin (n=16) on the bone matrix concentration of GFs was noticed. Postmenopausal women with osteoporosis on HRT (n=39) had lower skeletal IGF-I but not IGF-II levels as compared with age- and BMI-matched non-users. However, the lower rate of bone turnover in women with HRT may account for this difference, since the significance was lost after adjustment for alkaline phosphatase. Likewise, a tendency for lower TGF-beta 1 levels was observed in HRT users as compared with non-users but was lost after adjustment for bone turnover. None of the therapies influenced the serum levels of GFs when patients receiving continuous therapy for at least 1 Year before bone biopsy were considered.. Our data suggest no direct effect of fluor therapy on skeletal GFs levels. At the concentrations used, neither HRT nor calcitonin appeared to exert any significant influence on serum or bone matrix GF levels.

Topics: Biopsy; Bone Density; Calcitonin; Estrogen Replacement Therapy; Female; Growth Substances; Humans; Ilium; In Vitro Techniques; Insulin-Like Growth Factor I; Insulin-Like Growth Factor II; Male; Middle Aged; Osteoporosis; Sodium Fluoride; Transforming Growth Factor beta; Transforming Growth Factor beta1

Transforming growth factor-beta-1 (TGF-Beta(1)) has been implicated in bone mineral density (BMD) determination. We investigated the relationship between the TGF polymorphism, BMD, and vertebral fractures in 588 Chinese men and women. No association between TGF polymorphism and BMD was observed in postmenopausal women (aged 55-59 years), elderly men (aged 70-79 years), or elderly women (aged 70-79 years) at the hip, spine, or total body ( P >> 0.05 by two-way ANOVA). In all study groups, there was no effect of an interaction between TGF polymorphism and calcium intake on BMD ( P >> 0.05 for the interaction effects by two-way ANOVA). No statistical significant association was observed between TGF polymorphism and vertebral fracture in elderly men or women ( P >> 0.05 by the chi-square test), even though men of the TT and TC genotypes seem to have more vertebral fractures. Contrary to previous studies that found an association between BMD and TGF polymorphism in the Japanese, we found no association between TGF polymorphism and BMD of elderly Chinese men or women. This finding could result from different sampling methods between the previous and current studies and environmental factors and ethnic differences between the two populations.

Topics: Aged; Bone Density; Calcium, Dietary; China; Female; Genotype; Hip; Humans; Male; Middle Aged; Osteoporosis; Polymorphism, Genetic; Radiography; Spinal Fractures; Spine; Statistics as Topic; Transforming Growth Factor beta; Transforming Growth Factor beta1

The adequacy of association studies for complex diseases depends critically on the existence of linkage disequilibrium (LD) between functional alleles and surrounding SNP markers.. We examined the patterns of LD and haplotype distribution in eight candidate genes for osteoporosis and/or obesity using 31 SNPs in 1,873 subjects. These eight genes are apolipoprotein E (APOE), type I collagen alpha1 (COL1A1), estrogen receptor-alpha (ER-alpha), leptin receptor (LEPR), parathyroid hormone (PTH)/PTH-related peptide receptor type 1 (PTHR1), transforming growth factor-beta1 (TGF-beta1), uncoupling protein 3 (UCP3), and vitamin D (1,25-dihydroxyvitamin D3) receptor (VDR). Yin yang haplotypes, two high-frequency haplotypes composed of completely mismatching SNP alleles, were examined. To quantify LD patterns, two common measures of LD, D' and r2, were calculated for the SNPs within the genes. The haplotype distribution varied in the different genes. Yin yang haplotypes were observed only in PTHR1 and UCP3. D' ranged from 0.020 to 1.000 with the average of 0.475, whereas the average r2 was 0.158 (ranging from 0.000 to 0.883). A decay of LD was observed as the intermarker distance increased, however, there was a great difference in LD characteristics of different genes or even in different regions within gene.. The differences in haplotype distributions and LD patterns among the genes underscore the importance of characterizing genomic regions of interest prior to association studies.

Topics: Apolipoproteins E; Carrier Proteins; Collagen Type I; Collagen Type I, alpha 1 Chain; Estrogen Receptor alpha; Family Health; Female; Gene Frequency; Genetic Predisposition to Disease; Genotype; Haplotypes; Humans; Ion Channels; Linkage Disequilibrium; Male; Mitochondrial Proteins; Obesity; Osteoporosis; Polymorphism, Single Nucleotide; Receptor, Parathyroid Hormone, Type 1; Receptors, Calcitriol; Receptors, Cell Surface; Receptors, Estrogen; Receptors, Leptin; Statistics as Topic; Transforming Growth Factor beta; Transforming Growth Factor beta1; Uncoupling Protein 3

The aim of this study was to compare transcriptional regulation in vivo during anabolic bone formation induced by either estradiol (E2) treatment or intermittent parathyroid hormone[1-34] (PTH) therapy. We utilized an ovariectomized (OVX) mouse model of osteoporosis and transcriptional profiling to identify genes upregulated by either high-dose E2 or PTH. Five weeks post-OVX, the mice were administered either E2 and/or PTH, or vehicle for 4 weeks. Femoral bones were analyzed by microCT and histomorphometry to confirm the anabolic effect of each treatment. OVX vehicle-treated control mice lost metaphyseal trabecular bone, with significant decrease in trabecular number, thickness, and connectivity. Both E2 and PTH treatments increased trabecular and cortical bone indices above the level of the sham operated controls, fully restoring both bone volume and bone mineral density (BMD). Moreover, PTH/E2 combination treatment led to significantly greater increase in cancellous bone and BMD than would be expected from the additive effects of the separate treatments. To determine whether PTH and E2 treatments were stimulating similar bone anabolic mechanisms, or were activating distinct signaling pathways, we compared patterns of gene expression using transcriptional profiling after either E2 or PTH treatment. After 4, 11, and 24 days of treatment, total RNA was collected from both the distal femoral metaphysis and diaphysis. Transcriptional profiling was performed using Affymetrix GeneChip probe arrays, comprised of approximately 36,000 full-length mouse genes and EST clusters from the UniGene database. Several markers of osteoblast activity, including c-fos, RANKL, PHEX, and PTHR1, were consistently upregulated by PTH in both skeletal sites. PTH treatment also increased expression of Cathespin K, consistent with the predicted increase in osteoclast activity. E2 treatment upregulated a largely distinct set of genes, including TGFbeta3, and BMP1, as well as several genes critical for cell cycle control, including Cyclin D1 and CDK inhibitor 1A. Overall, comparison of transcriptional profiles suggest that anabolic responses in bone to PTH and high-dose E2 treatment after OVX-induced osteoporosis involve largely distinct patterns of gene regulation, each resulting in restoration of bone mass.

Topics: Absorptiometry, Photon; Animals; Bone and Bones; Bone Density; Bone Morphogenetic Protein 1; Bone Morphogenetic Proteins; Bone Resorption; Cathepsin K; Cathepsins; Estradiol; Female; Gene Expression Profiling; Gene Expression Regulation; Genes, cdc; Metalloendopeptidases; Mice; Osteoporosis; Ovariectomy; Parathyroid Hormone; Transforming Growth Factor beta; Transforming Growth Factor beta3

In a previous study (Jeong et al., 2003, Inhibition of Drynariae Rhizoma extracts on bone resorption mediated by processing of cathepsin K in cultured mouse osteoclasts. International Immunopharmacology 3, 1685-1697), treatment of osteoclasts-containing long bone cells with Drynariae Rhizoma (DR) extract prevented the intracellular maturation of cathepsin K and thus, it was considered that DR is a pro-drug of a potent bone resorption inhibitor. To further clarify the role of DR in ossification, we investigated the effects of DR on the proliferation and differentiation of osteoblastic cell lines in vitro. In this study, the bone effect of DR is studied. We assessed the effects of DR on osteoblastic differentiation in nontransformed osteoblastic cells (MC3T3-E1) and rat bone marrow cells. DR enhanced alkaline phosphatase (ALP) activity and mineralization in a dose- and time-dependent fashion. This stimulatory effect of the DR was observed at relatively low doses (significant at 50-150 microg/ml and maximal at 150 microg/ml). Northern blot analysis showed that the DR (100 microg/ml) increased in bone morphogenetic protein-2 as well as ALP mRNA concentrations in MC3T3-E1 cells. DR (60 microg/ml) slightly increased in type I collagen mRNA abundance throughout the culture period, whereas it markedly inhibited the gene expression of collagenase-1 between days 15 and 20 of culture. These results indicate that DR has anabolic effects on bone through the promotion of osteoblastic differentiation, suggesting that it could be used for the treatment of common metabolic bone diseases such as osteoporosis.

Topics: Alkaline Phosphatase; Animals; Bone Marrow Cells; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Cell Culture Techniques; Cell Differentiation; Collagen Type I; Collagenases; Dose-Response Relationship, Drug; Male; Mice; Osteoblasts; Osteogenesis; Osteoporosis; Plant Extracts; Polypodiaceae; Rats; Rats, Sprague-Dawley; RNA, Messenger; Transforming Growth Factor beta

We investigated the effects of 17betaestradiol and two selective estrogen receptor modulators, tamoxifen and raloxifene, on the expression and release of constitutive and interleukin-1-stimulated interleukin (IL)-6, transforming growth factor-beta1 (TGF-beta1) and insulin-like growth factor-1 by osteoblasts in primary culture from trabecular bone of healthy post-menopausal women. After 24 h incubation with 10(-8) M concentration of these compounds, there was no decrease in: a) the constitutive or IL-1beta-induced levels of IL-6 protein released to culture medium; b) the constitutive IL-6 mRNA expression after incubation of osteoblasts with 10(-8) M 17betaestradiol or 10(-8) M tamoxifen for 1, 3, 6, 24 or 30 h. Although a decrease after 30 h of treatment with 10(-8) M, raloxifene was found in mRNA IL-6 expression, and this fact was not reflected by a decrease in the release of IL-6 protein to the culture medium after 48 h of incubation with 10(-8) M or 10(-7) M raloxifene. Tumoral growth factorTGF-betal expression was not influenced by incubation with these compounds. Gene expression of IGF-I increased following 24 or 30 h incubation with 10(-8) M 17beta-estradiol and 30 h incubation with raloxifene. Tamoxifen did not affect IGF-I expression. In conclusion, the effects of estradiol or tamoxifen on bone metabolism do not appear to be mediated through the regulation of osteoblast IL-6 release or synthesis, but raloxifene produces a decrease in mRNA IL-6 expression. The actions of estradiol, tamoxifen and raloxifene do not appear to be mediated by tumoral growth factor TGF-beta1. On the other hand, an increase in IGF-I synthesis induced by raloxifene and estradiol could mediate, in part, the effects of these compounds on bone.

Topics: Aged; Antineoplastic Agents, Hormonal; Cell Culture Techniques; Estradiol; Estrogen Antagonists; Female; Humans; Insulin-Like Growth Factor I; Interleukin-6; Middle Aged; Osteoblasts; Osteoporosis; Postmenopause; Raloxifene Hydrochloride; RNA, Messenger; Tamoxifen; Transforming Growth Factor beta; Transforming Growth Factor beta1

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.

Topics: Alkaline Phosphatase; Bone and Bones; Bone Morphogenetic Protein 7; Bone Morphogenetic Proteins; Cell Communication; Cell Cycle; Cytoskeleton; Microscopy, Electron; Neuroprotective Agents; Osteoblasts; Osteocalcin; Osteogenesis; Osteoporosis; Procollagen; Space Flight; Transforming Growth Factor beta; Weight-Bearing; Weightlessness

Studies on polymorphisms of candidate genes and their association with bone mineral density (BMD) have been reported in many populations, but few have been reported in Chinese populations. We investigated polymorphisms of the following five commonly used markers of four prominent BMD candidate genes with the purpose of identifying useful genetic markers for osteoporosis genetic research in Chinese: the Sp1 and RsaI polymorphisms of the collagen type 1 alpha l (Col1a1) gene, the -174G/C promoter polymorphism of the interleukin 6 (IL-6) gene, the Asn363Ser polymorphism of the glucocorticoid receptor (GR) gene, and the T --> C polymorphism in intron 5 of the transforming growth factor beta(1) (TGF-beta(1)) gene. We evaluated these polymorphisms using PCR-RFLP in samples of at least 124 random individuals. We compared the polymorphisms of these five markers with other populations using the chi(2) test and Fisher's exact two-tailed test. For the RsaI polymorphism, only three heterozygotes but no variant homozygote were identified. For the -174G/C polymorphic site, only one GC heterozygote and no CC homozygote were found. Alleles s, Ser, and A(1) at the Sp1, Asn363Ser, and T --> C marker sites that have been found to be polymorphic in other populations were not found in Chinese. Significant differences of allele and genotype frequency distributions were observed at these polymorphisms ( P < 0.001) after comparing with other populations. Our results suggest that variant alleles of the five markers are absent or too rare to be useful genetic makers in Chinese, despite the fact that they have been commonly used as polymorphic markers in osteoporosis genetic research in other populations.

Topics: Base Sequence; Bone Density; China; Collagen Type I; DNA Primers; Ethnicity; Genetic Predisposition to Disease; Humans; Interleukin-6; Introns; Osteoporosis; Polymorphism, Genetic; Promoter Regions, Genetic; Receptors, Glucocorticoid; Transforming Growth Factor beta

Myelofibrosis and osteosclerosis are prominent features arising in mice overexpressing thrombopoietin (TPO). The pivotal role of transforming growth factor beta 1 (TGF-beta 1) in the pathogenesis of myelofibrosis has been documented, but the mechanisms mediating osteosclerosis remain unclear. Here, we used mice deficient in osteoprotegerin (OPG), a secreted inhibitor of bone resorption, to determine whether osteosclerosis occurs through a deregulation of osteoclastogenesis. Marrow cells from opg-deficient mice (opg(-/-)) or wild-type (WT) littermates were infected with a retrovirus encoding TPO and engrafted into an opg(-/-) or WT background for long-term reconstitution. The 4 combinations of graft/host (WT/WT, opg(-/-)/opg(-/-), opg(-/-)/WT, and WT/opg(-/-)) were studied. Elevation of TPO and TGF-beta 1 levels in plasma was similar in the 4 experimental groups and all the mice developed a similar myeloproliferative syndrome associated with severe myelofibrosis. Osteosclerosis developed in WT hosts engrafted with WT or opg(-/-) hematopoietic cells and was associated with increased OPG levels in plasma and decreased osteoclastogenesis. In contrast, opg(-/-) hosts exhibited an osteoporotic phenotype and a growth of bone trabeculae was rarely seen. These findings suggest that osteosclerosis in mice with TPO overexpression occurs predominantly via an up-regulation of OPG in host stromal cells leading to disruption of osteoclastogenesis.

Topics: Animals; Bone and Bones; Bone Marrow Transplantation; Cells, Cultured; Disease Models, Animal; Gene Expression Regulation; Genetic Vectors; Glycoproteins; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Myeloproliferative Disorders; Osteoclasts; Osteoporosis; Osteoprotegerin; Osteosclerosis; Primary Myelofibrosis; Radiation Chimera; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Recombinant Fusion Proteins; Retroviridae; Thrombopoietin; Transduction, Genetic; Transforming Growth Factor beta; Transforming Growth Factor beta1

Topics: Aged; Amino Acid Sequence; Bone Density; Cohort Studies; Female; Fractures, Bone; Genetic Predisposition to Disease; Genotype; Humans; Leucine; Multivariate Analysis; Osteoporosis; Polymorphism, Genetic; Proline; Proportional Hazards Models; Risk Factors; Transforming Growth Factor beta; Transforming Growth Factor beta1; United States; White People

Transforming growth factor (TGF)-beta1 is the most abundant growth factor in human bone. It is produced by osteoblasts and inhibits osteoclast proliferation and activity and stimulates proliferation and differentiation of preosteoblasts. Several polymorphisms have been described in the TGF-beta1 gene. Previously, we and others have found associations between some of these polymorphisms and bone mass. We therefore wanted to examine if these polymorphisms are also predictors of osteoporotic fractures. The polymorphisms G(-1639)-A, C(-1348)-T, C(-765)insC, T(29)-C, G(74)-C, 713-8delC, C(788)-T, and T(816-20)-C were examined using RFLP and sequencing in 296 osteoporotic patients with vertebral fractures and 330 normal individuals. Bone mineral density (BMD) was examined at the lumbar spine and at the femoral neck by DXA. Genotype distributions were in H-W equilibrium. Linkage disequilibrium was found between the polymorphisms. The T(816-20)-C genotypes were distributed differently among osteoporotic patients and normal controls. The TT genotype was less common in individuals with osteoporotic fractures (chi(2) = 6.02, P < 0.05). BMD was higher in individuals with the TT-genotype (T(816-20)-C) at the lumbar spine, 0.960 +/- 0.173 g/cm(2) compared with individuals with the TC or CC genotypes: 0.849 +/- 0.181 g/cm(2) and 0.876 +/- 0.179 g/cm(2), respectively (P < 0.001, ANOVA). Similar differences between genotypes were found at the different hip regions as well as at the total hip. Individuals with the TT-genotype (C(-1348)-T) had higher bone mass at the femoral neck: 0.743 +/- 0.134 g/cm(2) compared with 0.703 +/- 0.119 g/cm(2) in individuals with TC or CC genotypes (P < 0.05). Individuals with the CC-genotype (T(29)-C) had higher bone mass at the femoral neck, 0.735 +/- 0.128 g/cm(2) compared with 0.703 +/- 0.120 g/cm(2) in individuals with TC or TT genotypes (P < 0.05) and at the total hip: 0.852 +/- 0.166 g/cm(2) vs. 0.818 +/- 0.149 g/cm(2), respectively (P < 0.05). None of the other polymorphisms were distributed differently in patients and controls and did not affect BMD. In conclusion, The TT genotype of the T(816-20)-C polymorphism is less common in patients with osteoporotic fractures and is associated with higher bone mass both at the lumbar spine and at the hip. The C(-1348)-T and T(29)-C polymorphisms were distributed similarly in osteoporotic patients and normal controls, however, the rare genotypes were associated with higher bone mass at the hip.

Topics: Adult; Aged; Biomarkers; Bone Density; Exons; Female; Femur Neck; Genotype; Humans; Lumbar Vertebrae; Male; Middle Aged; Osteoporosis; Polymorphism, Genetic; Promoter Regions, Genetic; Transforming Growth Factor beta; Transforming Growth Factor beta1

GDF8 (myostatin), a member of the transforming growth factor (TGF)-beta superfamily of secreted growth and differentiation factors, is a negative regulator of skeletal muscle growth. GDF8 knockout mice have approximately twice the skeletal muscle mass of normal mice. The effects of increased muscle mass on bone modeling were investigated by examining bone mineral content (BMC) and bone mineral density (BMD) in the femora of female GDF8 knockout mice. Dual-energy X-ray absorptiometry (DEXA) densitometry was used to measure whole-femur BMC and BMD, and pQCT densitometry was used to calculate BMC and BMD from cross-sections taken at two different locations: the midshaft and the distal metaphysis. The DEXA results show that the knockout mice have significantly greater femoral BMD than normal mice. The peripheral quantitative computed tomography (pQCT) data indicate that the GDF8 knockout mice have approximately 10% greater cortical BMC (P =.01) at the midshaft and over 20% greater cortical BMC at the metaphysis (P <.001). Likewise, knockouts show approximately 10% greater cortical thickness (P <.001) and significantly greater cortical BMD (P <.001) at both locations. These results suggest that inhibitors of GDF8 function may be useful pharmacological agents for increasing both muscle mass and BMD.

Topics: Absorptiometry, Photon; Animals; Bone Density; Bone Remodeling; Feedback, Physiological; Female; Femur; Growth Inhibitors; Hypertrophy; Mice; Mice, Inbred C57BL; Mice, Knockout; Muscle, Skeletal; Myostatin; Osteoporosis; Transforming Growth Factor beta; Up-Regulation

A single nucleotide polymorphism (SNP) within the transforming growth factor-beta1 (TGF-beta1) gene was detected by hybridization-based method using bacterial magnetic particles (BMPs). TGF-beta1 is commonly associated with a single base change resulting in a Leu(10)-->Pro (T(869)-->C) polymorphism and is a genetic marker for susceptibility to osteoporosis. Short (9 bases) and specific probes were designed to detect SNP in TGF-beta1. Detection probes were immobilized on BMPs using cross-linking reagents. TGF-beta1 PCR products (139 bp) were labeled with the fluorescent dye coumarin and hybridized with detection probes on BMPs. Complementary hybridized targets gave over four times higher fluorescent intensities, compared with one base mismatched hybridizations. The SNP genotype was successfully discriminated using this technique.

Topics: Bacterial Proteins; Coated Materials, Biocompatible; Gene Expression Profiling; Humans; In Situ Hybridization, Fluorescence; Membrane Proteins; Osteoporosis; Polymorphism, Single Nucleotide; Spectrometry, Fluorescence; Temperature; Transforming Growth Factor beta; Transforming Growth Factor beta1

Osteogenic protein-1 (OP-1, BMP-7) induces bone formation and cartilage growth. Since OP-1 is an anabolic factor expressed by human articular chondrocytes, we examined the response of endogenous OP-1 to interleukin-1beta (IL-1beta) in human articular cartilage.. Normal adult human articular cartilage explants were cultured for twenty-five days in the presence of medium only or were treated with a low dose (0.1 ng/mL) or high dose (1.0 ng/mL) of IL-1beta for forty-eight or ninety-six hours. Alternately, cartilage explants were cultured forty-eight hours with IL-1beta, followed by forty-eight hours in standard medium (recovery). Tissue was analyzed for OP-1 message (by means of the reverse transcriptase-polymerase chain reaction), protein (by means of enzyme-linked immunosorbent assay and Western blot analysis) and proteoglycan content. Medium was analyzed for released proteoglycans and OP-1.. In the presence of medium, OP-1 maintained its steady state of mRNA and protein expression for as long as twenty-five days in culture. A low dose of IL-1beta led to some upregulation in message and a twofold (p < 0.02) increase in OP-1 protein characterized by enhanced processing and activation of OP-1. Removal of IL-1beta (recovery experiments) did not reverse its effect on OP-1 synthesis. A high dose of IL-1beta caused stronger upregulation of message and a twofold decrease in OP-1 protein content (p < 0.007) in the cartilage matrix. However, this decrease in the matrix was primarily due to a release of active OP-1 into the medium. After removal of the 1.0-ng/mL IL-1beta, the levels of OP-1 protein did not recover.. The results of the present study indicate that human adult chondrocytes have an ability to respond anabolically to initial or early catabolic events through an upregulation of endogenous OP-1.

Topics: Aged; Bone Morphogenetic Protein 7; Bone Morphogenetic Proteins; Cartilage, Articular; Cell Differentiation; Cells, Cultured; Female; Gene Expression Regulation; Humans; Interleukin-1; Male; Middle Aged; Osteoporosis; RNA, Messenger; Transforming Growth Factor beta; Up-Regulation

Topics: Aged; Aging; Animals; Estrogens; Female; Humans; Male; Osteoblasts; Osteoporosis; Osteoporosis, Postmenopausal; Transforming Growth Factor beta

Human transforming growth factor-beta1 (TGFB1) is a family of polypeptides that regulate cell growth, cell differentiation, and cell function as a multifunctional regulator of cellular activity. TGFB1 is produced by osteoblasts and stored in substantial amounts in the bone matrix, which is an important regulator of both skeletal development and homeostasis of bone metabolism. In the present study, we identified four new polymorphisms in TGFB1 and examined whether these polymorphisms are risk factors for osteoporosis. We have sequenced all exons including in the promoter region up to -1,800bp to identify additional genetic polymorphisms in TGFB1. Four novel polymorphisms were newly identified: one in 5' region (g.14129555_14129557dupAGG), one in promoter region (g.14128838C>T), and two in intron (g.14106505G>A and g.14106215G>A). Two known SNPs (g.14128554C>T and g.14127139T>C) were also confirmed. The frequencies of each SNP were 0.479 (g.14129555_14129557dupAGG), 0.007 (g.14128838C>T), 0.478 (g.14128554C>T), 0.476 (g.14127139T>C), 0.016 (g.14106505G>A), and 0.004 (g.14106215G>A) in the Korean population (n=1,885), respectively. Haplotypes and their frequencies were estimated by EM algorithm, and linkage disequilibrium coefficients (mid R:/D'/: and r2) between polymorphism pairs were calculated. We analyzed genetic associations of TGFB1 polymorphisms and haplotypes with spinal bone mineral density (BMD) value of 433 postmenopausal Korean women. By statistical analysis, we could not find any associations with spinal BMD. The information from this study of the critical TGFB1 would be useful for genetic studies of other diseases.

Topics: Asian People; Bone Density; Bone Diseases, Metabolic; Female; Genetic Variation; Humans; Osteoporosis; Osteoporosis, Postmenopausal; Postmenopause; Spine; Transforming Growth Factor beta; Transforming Growth Factor beta1

Long-term administration of glucocorticoids (GCs) causes osteoporosis with a rapid and severe bone loss and with a slow and prolonged bone disruption. Although the involvement of GCs in osteoblastic proliferation and differentiation has been studied extensively, their direct action on osteoclasts is still controversial and not conclusive. In this study, we investigated the direct participation of GCs in osteoclastogenesis. Dexamethasone (Dex) at <10(-8) M stimulated, but at >10(-7) M depressed, receptor activator of NF-kappaB ligand (RANKL)-induced osteoclast formation synergistically with transforming growth factor-beta. The stimulatory action of Dex was restricted to the early phase of osteoclast differentiation and enhanced the priming of osteoclast progenitors (bone marrow-derived monocytes/macrophages) toward differentiation into cells of the osteoclast lineage. The osteoclast differentiation depending on RANKL requires the activation of NF-kappaB and AP-1, and the DNA binding of these transcription factors to their respective consensus cis-elements was enhanced by Dex, consistent with the stimulation of osteoclastogenesis. However, Dex did not affect the RANKL-induced signaling pathways such as the activation of IkappaB kinase followed by NF-kappaB nuclear translocation or the activation of JNK. On the other hand, Dex significantly decreased the endogenous production of interferon-beta, and this cytokine depressed the RANKL-elicited DNA binding of NF-kappaB and AP-1, as well as osteoclast formation. Thus, the down-regulation of inhibitory cytokines such as interferon-beta by Dex may allow the osteoclast progenitors to be freed from the suppression of osteoclastogenesis, resulting in an increased number of osteoclasts, as is observed in the early phase of GC-induced osteoporosis.

Topics: Acid Phosphatase; Animals; Bone Marrow Cells; Carrier Proteins; Cell Differentiation; Dexamethasone; DNA; Drug Synergism; Glucocorticoids; Humans; Interferon-beta; Macrophage Colony-Stimulating Factor; Membrane Glycoproteins; Mice; Mice, Inbred ICR; NF-kappa B; Osteoclasts; Osteoporosis; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Recombinant Proteins; RNA, Messenger; Signal Transduction; Spectrometry, Fluorescence; Stem Cells; Transcription Factor AP-1; Transforming Growth Factor beta

Osteoporosis is a disease that is strongly genetically determined and polymorphisms present in a range of candidate genes may be involved. A number of previous studies have shown an association between the T869C functional polymorphism of the gene for transforming growth factor beta (TGF beta) and bone mineral density (BMD) and fracture, but these studies have been limited to relatively small studies of selected subjects. In a population-based study of 1337 white women over age 70 we examined the TGF beta T869 polymorphism in relation to BMD, calcaneal quantitative ultrasound (QUS), and prevalent and incident fracture. The TGF beta C allele was observed in 50% of the subjects and was associated with reduced hip BMD at all sites (2.8% total hip, 2.4% femoral neck, 2.6% intertrochanter, and 3.4% trochanter) compared to the TGF beta TT genotype. The TGF beta C allele was also associated with a reduction in the QUS parameters BUA, SOS, and stiffness of 0.87%, 0.26%, and 2.4%, respectively, compared to the TGF beta TT genotype. After adjustment for body mass index in an analysis of variance model, the effect of the TGF beta C allele remained significant at the total hip, the femoral neck, and the trochanter, and for the QUS SOS and stiffness parameters. The TGF beta C allele was associated with an increase in osteoporosis [T score < or =-2.5 SD; odds ratio (OR) 2.07; 95% confidence interval (CI) 1.19-3.60] and prevalent fracture (1.37; 95% CI 1.06-1.75). After adjustment for BMD and QUS stiffness, the association of the TGF beta C allele with prevalent fracture was still present (OR 1.40; 95% CI 1.04-1.89), suggesting that the effect of the C allele on fracture was independent of a reduction in BMD and QUS stiffness. Subjects with normal BMD and a TGF beta C allele had an increased risk of incident fracture over 3 years compared to subjects with normal BMD and a TGF beta TT genotype (relative risk 3.95; 95% CI 1.52-10.29). This association was not found in osteopenic or in osteoporotic subjects, indicating a BMD-TGF beta C allele interaction in relation to the association of the TGF beta C allele with fracture risk. These findings are of potential clinical usefulness, as the TGF beta T869C genotype could be used, in conjunction with other genetic and clinical information, to determine an individual's risk of osteoporosis.

Topics: Aged; Bone Density; Bone Diseases, Metabolic; Calcaneus; Female; Fractures, Bone; Gene Frequency; Genetic Predisposition to Disease; Humans; Incidence; Osteoporosis; Polymorphism, Genetic; Prevalence; Risk Factors; Transforming Growth Factor beta; Ultrasonography

Osteoporotic fractures are a major cause of morbidity and mortality in ageing populations. Osteoporosis, defined as low bone mineral density (BMD) and associated fractures, have significant genetic components that are largely unknown. Linkage analysis in a large number of extended osteoporosis families in Iceland, using a phenotype that combines osteoporotic fractures and BMD measurements, showed linkage to Chromosome 20p12.3 (multipoint allele-sharing LOD, 5.10; p value, 6.3 x 10(-7)), results that are statistically significant after adjusting for the number of phenotypes tested and the genome-wide search. A follow-up association analysis using closely spaced polymorphic markers was performed. Three variants in the bone morphogenetic protein 2 (BMP2) gene, a missense polymorphism and two anonymous single nucleotide polymorphism haplotypes, were determined to be associated with osteoporosis in the Icelandic patients. The association is seen with many definitions of an osteoporotic phenotype, including osteoporotic fractures as well as low BMD, both before and after menopause. A replication study with a Danish cohort of postmenopausal women was conducted to confirm the contribution of the three identified variants. In conclusion, we find that a region on the short arm of Chromosome 20 contains a gene or genes that appear to be a major risk factor for osteoporosis and osteoporotic fractures, and our evidence supports the view that BMP2 is at least one of these genes.

Topics: Alleles; Bone Density; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Chromosome Mapping; Chromosomes, Human, Pair 20; Cohort Studies; Genetic Linkage; Genetic Variation; Genotype; Haplotypes; Humans; Iceland; Linkage Disequilibrium; Lod Score; Molecular Sequence Data; Mutation, Missense; Osteoporosis; Phenotype; Polymorphism, Genetic; Polymorphism, Single Nucleotide; Risk Factors; Transforming Growth Factor beta

Osteoporosis is a disease manifested in drastic bone loss resulting in osteopenia and high risk for fractures. This disease is generally divided into two subtypes. The first, post-menopausal (type I) osteoporosis, is primarily related to estrogen deficiency. The second, senile (type II) osteoporosis, is mostly related to aging. Decreased bone formation, as well as increased bone resorption and turnover, are thought to play roles in the pathophysiology of both types of osteoporosis. In this study, we demonstrate in murine models for both type I (estrogen deficiency) and type II (senile) osteopenia/osteoporosis that reduced bone formation is related to a decrease in adult mesenchymal stem cell (AMSC) number, osteogenic activity, and proliferation. Decreased proliferation is coupled with increased apoptosis in AMSC cultures obtained from osteopenic mice. Recombinant human bone morphogenetic protein (rhBMP-2) is a highly osteoinductive protein, promoting osteogenic differentiation of AMSCs. Systemic intra-peritoneal (i.p.) injections of rhBMP-2 into osteopenic mice were able to reverse this phenotype in the bones of these animals. Moreover, this change in bone mass was coupled to an increase in AMSCs numbers, osteogenic activity, and proliferation as well as a decrease in apoptosis. Bone formation activity was increased as well. However, the magnitude of this response to rhBMP-2 varied among different stains of mice. In old osteopenic BALB/c male mice (type II osteoporosis model), rhBMP-2 systemic treatment also restored both articular and epiphyseal cartilage width to the levels seen in young mice. In summary, our study shows that AMSCs are a good target for systemically active anabolic compounds like rhBMP-2.

Topics: Aging; Alkaline Phosphatase; Animals; Apoptosis; Bone and Bones; Bone Diseases, Metabolic; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Cartilage; Cells, Cultured; Dose-Response Relationship, Drug; Enzyme Activation; Female; Humans; Male; Mesoderm; Mice; Mice, Inbred BALB C; Mice, Inbred ICR; Osteogenesis; Osteoporosis; Ovariectomy; Recombinant Proteins; Stem Cells; Transforming Growth Factor beta

Biglycan (bgn) is an extracellular matrix proteoglycan that is enriched in bone and other skeletal connective tissues. Previously, we generated bgn-deficient mice and showed that they developed age-dependent osteopenia. To identify the cellular events that might contribute to this progressive osteoporosis, we measured the number of osteogenic precursors in the bone marrow of normal and mutant mice. The number of colonies, indicative of the colony-forming unit potential of fibroblasts (CFU-F), gradually decreased with age. By 24 weeks of age, colony formation in the bgn knockout (KO) mice was significantly more reduced than that in the wild type (wt) mice. This age-related reduction was consistent with the extensive osteopenia previously shown by X-ray analysis and histological examination of 24-week-old bgn KO mice. Because bgn has been shown previously to bind and regulate transforming growth factor beta (TGF-beta) activity, we also asked whether this growth factor would affect colony formation. TGF-beta treatment significantly increased the size of the wt colonies. In contrast, TGF-beta did not significantly influence the size of the bgn colonies. An increase in apoptosis in bgn-deficient bone marrow stromal cells (BMSCs) was observed also. The combination of decreased proliferation and increased apoptosis, if it occurred in vivo, would lead to a deficiency in the generation of mature osteoblasts and would be sufficient to account for the osteopenia developed in the bgn KO mice. The bgn KO mice also were defective in the synthesis of type I collagen messenger RNA (mRNA) and protein. This result supports the suggestion that the composition of the extracellular matrix may be regulated by specific matrix components including bgn.

Topics: Animals; Apoptosis; Biglycan; Bone Marrow; Collagen Type I; Colony-Forming Units Assay; Extracellular Matrix Proteins; Male; Mice; Mice, Inbred Strains; Mice, Mutant Strains; Osteoporosis; Proteoglycans; Stromal Cells; Transforming Growth Factor beta

The development of methods to culture bone cells has enhanced in vitro studies and allowed researchers to investigate bone cell metabolism in healthy tissue and in various different bone diseases. Greater knowledge of cultures of pathologic bone tissue-derived osteoblasts may be helpful in performing in vitro experiments that test biomaterials and therapies to be used in the orthopedic field, since this kind of approach better reflects the conditions of clinical relevance to many patients. In the present study primary cultures of human osteoblastic cells were isolated from donors with osteoporosis (HOB, Human Osteopenic Bone) and their respective controls (HNB, Human Normal Bone). They were then characterized in baseline conditions and after stimulation with 10(-9) M 1,25(OH2)D3. Specific biochemical markers of bone cells and cytokines involved in bone turnover were evaluated to assess cell metabolism and any possible differences between osteoblasts derived from healthy and osteopenic bone tissue. Under baseline conditions, HNB and HOB in vitro cultures showed some differences in proliferation (MTT test), PICP, OC and IL-6. The HNB response to 1,25-(OH2)D3 stimulation differed significantly from that of the HOB cultures but only with regard to the MTT test, and ALP and PICP levels; the other selected parameters showed a similar behavior for both cultures. The current findings should be taken into account when cultures derived from human bone are used for in vitro experiments.

Topics: Alkaline Phosphatase; Biomarkers; Calcitriol; Cells, Cultured; Cytokines; Humans; Interleukin-6; Osteoblasts; Osteocalcin; Osteoporosis; Peptide Fragments; Procollagen; Transforming Growth Factor beta; Transforming Growth Factor beta1

Transforming growth factor beta, TGF-beta, is expressed during tooth formation and can induce pre-odontoblast differentiation and formation of functional odontoblast-like cells in vitro. In addition, exogenous TGF-beta can increase reparative dentin formation, presumably by acting on odontoblasts. In this study, we examined the tooth phenotype of transgenic mice, in which TGF-beta 2 expression is directed by the osteocalcin promoter. Previous studies have shown that these mice have a bone phenotype that resembles that of human osteoporosis, including the existence of spontaneous fractures. Microhardness testing of the enamel and dentin showed no differences in the molars of these transgenic mice as compared with those of their wild-type littermates. Consistent with the increase in bone mineral apposition rate previously reported in these mice, the dentin apposition rate appeared to be increased in the TGF-beta 2-overexpressing mice. Thus, in teeth, as in bone, TGF-beta 2 appears to stimulate the synthesis and deposition of matrix. Further studies are needed to understand the effect of TGF-beta 2 on distinct mineralized tissues (bone, dentin, and cementum) and to determine whether exogenous TGF-beta 2 may be useful for tooth repair.

Topics: Animals; Calcification, Physiologic; Cell Differentiation; Cementogenesis; Dental Enamel; Dentin; Dentin, Secondary; Dentinogenesis; Disease Models, Animal; Hardness; Humans; Image Processing, Computer-Assisted; Male; Mice; Mice, Transgenic; Odontoblasts; Osteocalcin; Osteoporosis; Phenotype; Promoter Regions, Genetic; Tooth Calcification; Transforming Growth Factor beta; Transforming Growth Factor beta2

Bone mineral density (BMD) in later life is a major determinant of osteoporotic fracture risk and has been shown to be under strong genetic influence. Transforming growth factor beta 1 (TGF-beta 1) is an important regulatory cytokine, is found in high concentrations in the bone matrix, and is a plausible candidate for the genetic regulation of BMD.. This study investigated whether a novel polymorphism within the TGF-beta 1 gene is associated with BMD in a large normal female population of 1706 dizygotic (DZ) twins (age range 18-76 yr).. A C--->T [corrected] polymorphism was identified in intron 5, the T [corrected] allele having a frequency of 0.25. Subjects homozygous for the presence of the TGF-beta 1 T [corrected] allele had a 4% reduction in femoral neck BMD compared with the other two genotype groups (P<0.025). No effect was seen at the lumbar spine or ultradistal radius, or with calcaneal ultrasound measurements. Results were unaffected after adjustment for potential confounders. These findings were predominantly seen in pre-menopausal subjects, suggesting that this locus has an effect on the attainment of peak BMD. In pre-menopausal women, subjects who were homozygous for the T [corrected] allele had a 5-fold excess risk of having osteoporosis at the femoral neck compared with the other genotype groups. A within-pair analysis using the sibling transmission disequilibrium test confirmed these findings in pre-menopausal women and supported the candidacy of the TGF-beta 1 locus in the genetic regulation of hip BMD.. These results indicate that allelic variation at the TGF-beta 1 gene contributes to the development of osteoporosis at the hip. The study also highlights the power of candidate gene analysis in twins, in whom loci having modest effects on disease risk can be identified.

Topics: Adolescent; Adult; Aged; Bone Density; Female; Genetic Predisposition to Disease; Genetic Testing; Hip; Humans; Linkage Disequilibrium; Middle Aged; Osteoporosis; Premenopause; Transforming Growth Factor beta; Transforming Growth Factor beta1; Twin Studies as Topic

Topics: Adult; Aged; Bone Density; Cohort Studies; Female; Genotype; Humans; Male; Middle Aged; Osteoporosis; Polymorphism, Genetic; Risk Factors; Transforming Growth Factor beta; Transforming Growth Factor beta1

Transforming growth factor-beta1 is an important local regulator of bone metabolism, acting downstream of estrogen and cooperatively with vitamin D. The possible association of a C 509-->T polymorphism in the promoter region of the transforming growth factor-beta1 gene, alone or in combination with a T869-->C (Leu10-->Pro) polymorphism, with bone mineral density and genetic susceptibility to osteoporosis was investigated in 625 postmenopausal Japanese women. The frequencies of the CC, CT, and TT genotypes of the C-509-->T polymorphism in the study population were 24%, 49%, and 27%, respectively. A significant association of C-509-->T genotype with bone mineral density was detected: lumbar spine (L2-L4) and total body bone mineral density values were 7% and 5% lower, respectively, in individuals with the TT genotype than in those with the CT or CC genotype. The serum concentration of transforming growth factor-beta1 did not vary with C-509-->T genotype. Multivariable logistic regression analysis, with adjustment for age, height, body weight, time since menopause, smoking status, body fat mass, and lean mass, revealed a significantly higher frequency of the TT genotype of the C-509-->T polymorphism in 286 individuals with osteoporosis than in 170 normal controls. Analysis of combined C-509-->T and T869-->C genotypes showed that L2-L4 bone mineral density decreases and the prevalence of osteoporosis increases with the number of T alleles. These results suggest that the C-509-->T polymorphism, alone or in combination with the T869-->C polymorphism, of the transforming growth factor-beta1 gene is a genetic determinant of bone mass, and that the number of T alleles in the combined genotype is a risk factor for the genetic susceptibility to osteoporosis in postmenopausal Japanese women.

Topics: Aged; Bone Density; Female; Genetic Predisposition to Disease; Humans; Japan; Middle Aged; Osteoporosis; Polymorphism, Genetic; Transforming Growth Factor beta

In the mouse, ovariectomy (OVX) leads to significant reductions in cancellous bone volume while estrogen (17beta-estradiol, E2) replacement not only prevents bone loss but can increase bone formation. As the E2-dependent increase in bone formation would require the proliferation and differentiation of osteoblast precursors, we hypothesized that E2 regulates mesenchymal stem cells (MSCs) activity in mouse bone marrow. We therefore investigated proliferation, differentiation, apoptosis, and estrogen receptor (ER) alpha and beta expression of primary culture MSCs isolated from OVX and sham-operated mice. MSCs, treated in vitro with 10(-7) M E2, displayed a significant increase in ERalpha mRNA and protein expression as well as alkaline phosphatase (ALP) activity and proliferation rate. In contrast, E2 treatment resulted in a decrease in ERbeta mRNA and protein expression as well as apoptosis in both OVX and sham mice. E2 up-regulated the mRNA expression of osteogenic genes for ALP, collagen I, TGF-beta1, BMP-2, and cbfa1 in MSCs. In a comparison of the relative mRNA expression and protein levels for two ER isoforms, ERalpha was the predominant form expressed in MSCs obtained from both OVX and sham-operated mice. Cumulatively, these results indicate that estrogen in vitro directly augments the proliferation and differentiation, ERalpha expression, osteogenic gene expression and, inhibits apoptosis and ERbeta expression in MSCs obtained from OVX and sham-operated mice. Co-expression of ERalpha, but not ERbeta, and osteogenic differentiation markers might indicate that ERalpha function as an activator and ERbeta function as a repressor in the osteogenic differentiation in MSCs. These results suggest that mouse MSCs are anabolic targets of estrogen action, via ERalpha activation. J. Cell. Biochem. Suppl. 36: 144-155, 2001.

Topics: Alkaline Phosphatase; Animals; Apoptosis; Bone Marrow Cells; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Cell Differentiation; Cell Division; Cells, Cultured; Collagen; Collagen Type I; Collagen Type I, alpha 1 Chain; Core Binding Factor Alpha 1 Subunit; Estradiol; Estrogen Receptor alpha; Estrogen Receptor beta; Female; Immunohistochemistry; Mesoderm; Mice; Neoplasm Proteins; Osteogenesis; Osteoporosis; Ovariectomy; Receptors, Estrogen; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Stem Cells; Transcription Factors; Transforming Growth Factor beta; Transforming Growth Factor beta1

Osteoporosis is a disease affecting mainly women but also an increasing number of men. The destruction of the bone microarchitecture and the reduction of bone mass lead to increased fragility and pathologic bone fractures. Family studies and twin studies have shown that peak bone mass, mechanical strength, and physiological bone turnover are subject to genetic control. Vitamin D receptor polymorphisms were one of the first genetic factors suggested to influence bone phenotype, although their impact on bone metabolism was initially overestimated. Meanwhile, polymorphisms in numerous other genes such as collagen I alpha 1, estrogen receptor, transforming growth factor beta (TGF-beta), interleukin-1, interleukin-6, calcitonin, parathyroid hormone, and apolipoprotein E have been found to be associated with bone mineral density. In the interpretation of genetic findings, genetic differences between different ethnic groups, environmental factors such as calcium intake, vitamin D status, hormonal status, body size, and total body bone mineral density have to be considered. Understanding the molecular physiology of the genes described in this article and all genes influencing bone metabolism identified in the future will enable us to identify persons at risk for osteoporosis and to develop more specific therapies.

Topics: Apolipoproteins A; Bone and Bones; Bone Density; Calcitonin; Collagen; Diagnosis, Differential; Diseases in Twins; Female; Genotype; Humans; Interleukin-1; Interleukin-6; Male; Osteoporosis; Parathyroid Hormone; Phenotype; Polymorphism, Genetic; Receptors, Calcitriol; Receptors, Estrogen; Sex Factors; Transforming Growth Factor beta

Topics: Bone Density; Genetic Markers; Humans; Interleukin-6; Osteoporosis; Receptors, Calcitriol; Receptors, Estrogen; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha

In humans, low peak bone mass is a significant risk factor for osteoporosis. We report that LRP5, encoding the low-density lipoprotein receptor-related protein 5, affects bone mass accrual during growth. Mutations in LRP5 cause the autosomal recessive disorder osteoporosis-pseudoglioma syndrome (OPPG). We find that OPPG carriers have reduced bone mass when compared to age- and gender-matched controls. We demonstrate LRP5 expression by osteoblasts in situ and show that LRP5 can transduce Wnt signaling in vitro via the canonical pathway. We further show that a mutant-secreted form of LRP5 can reduce bone thickness in mouse calvarial explant cultures. These data indicate that Wnt-mediated signaling via LRP5 affects bone accrual during growth and is important for the establishment of peak bone mass.

Topics: Adaptor Proteins, Signal Transducing; Adult; Animals; Animals, Outbred Strains; Bone Density; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Child; Child, Preschool; Chlorocebus aethiops; Chromosomes, Human, Pair 11; COS Cells; Culture Media, Conditioned; Dishevelled Proteins; DNA, Complementary; Eye; Eye Abnormalities; Female; Genes, Recessive; Heterozygote; Humans; LDL-Receptor Related Proteins; Low Density Lipoprotein Receptor-Related Protein-5; Male; Mesoderm; Mice; Mice, Inbred C57BL; Organ Culture Techniques; Osteoblasts; Osteoporosis; Phosphoproteins; Proteins; Proto-Oncogene Proteins; Receptors, LDL; Recombinant Fusion Proteins; Recombinant Proteins; Signal Transduction; Skull; Species Specificity; Stromal Cells; Syndrome; Transfection; Transforming Growth Factor beta; Wnt Proteins; Wnt-5a Protein; Wnt2 Protein; Wnt3 Protein; Wnt4 Protein; Zebrafish Proteins

To investigate the status of apoptosis of osteoblast, osteoclast and the relative factors.. Apoptotic cells were examined using in situ end labeling technique. Expressions of bcl-2, Fas and transforming growth factor(TGF) beta1 were observed with immunohistochemical method.. Positive expression rate (40.5 +/- 5.2)% of apoptosis cells was significantly increased in the osteoblast, but the expression rate of apoptosis cells (8.4 +/- 1.2)% was significantly decreased in the osteoclast of the post-ovariectomy rats than in the sham-operated rats. The expression of Fas was decreased in osteoclast (20.0%) and increased in osteoblast (80.0%) of the post-ovariectomized rats. The expression of TGFbeta1 was significantly decreased in the osteoclast (0) and the osteoblast (20.0%) of the post-ovariectomized rats. The above-mentioned targets in post-ovariectomized rats treated with nylestriol/levonorgestrel were close to those sham-operated rats (P > 0.05).. Bone loss in the post-ovariectomized rats is attributable to the lower level of estrogen so that the apoptosis cells were decreased in osteoclast but were increased in osteoblast. As a result, the process of bone absorption prevails over that of bone formation. Expression of TGFbeta1 depends on stimulation of estrogen. TGFbeta1 may stimulate apoptosis of osteoclast and restrain apoptosis of osteoblast. Fas can induce the apoptosis of osteoclast.

Topics: Animals; Apoptosis; fas Receptor; Female; Immunohistochemistry; Osteoblasts; Osteoclasts; Osteoporosis; Ovariectomy; Rats; Rats, Sprague-Dawley; Transforming Growth Factor beta; Transforming Growth Factor beta1

Topics: Animals; Anticholesteremic Agents; Bone Diseases, Metabolic; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Bone Resorption; Female; Humans; Hypercholesterolemia; Male; Models, Biological; Osteoporosis; Transforming Growth Factor beta

To examine the possible relationship between a T-->C polymorphism at nucleotide position 29 of the transforming growth factor beta1 (TGFbeta1) gene and genetic susceptibility to radiographic spinal osteophytosis.. A total of 540 postmenopausal Japanese women were subjected to radiography of the spine and determination of bone mineral density (BMD) for the lumbar spine and total body. Changes in lumbar intervertebral discs were examined in 67 individuals with either osteoporosis or spinal osteophytosis by magnetic resonance imaging (MRI). TGFbeta1 genotype was determined with an allele-specific polymerase chain reaction assay. The serum concentration of TGFbeta1 was measured in 29 control subjects and in 36 patients with spinal osteophytosis.. Among all study subjects, the prevalence of radiographic spinal osteophytosis in individuals with the CC genotype was greater than that in those with the TC or TT genotype. Logistic regression analysis, adjusted for age, height, body weight, time since menopause, smoking status, body fat, lean mass, and either lumbar spine or total body BMD, demonstrated that the frequency of the C allele in subjects with spinal osteophytosis was significantly greater than that in those without this condition. Comparison among control, osteoporosis, and spinal osteophytosis groups also revealed that the C allele was more prevalent in subjects with osteophytosis than in controls, even after adjustment for BMD. In contrast, as previously shown, the frequency of the C allele was lower in osteoporosis patients than in controls. The intervertebral disc area and the ratio of disc area to vertebral body area, as determined by MRI, were also lowest in subjects with the CC genotype. The serum concentration of TGFbeta1 increased with the number of C alleles in both controls and patients with spinal osteophytosis.. The T29-->C polymorphism of the TGFbeta1 gene exhibited inverse patterns of association with genetic susceptibility to spinal osteophytosis and with osteoporosis. Although radiographic evaluation of osteophytes might not reflect the actual disease severity, the C allele, which protects against osteoporosis, may be a risk factor for genetic susceptibility to spinal osteophytosis.

Topics: Aged; Female; Genetic Predisposition to Disease; Genetic Testing; Genotype; Humans; Japan; Logistic Models; Middle Aged; Multivariate Analysis; Osteoporosis; Polymorphism, Genetic; Postmenopause; Radiography; Spinal Osteophytosis; Transforming Growth Factor beta

Bone morphogenetic protein (BMP)-2, a member of the BMP family, plays an important role in osteoblast differentiation and bone formation. To discover small molecules that induce BMP-2, a luciferase reporter vector containing the 5'-flanking promoter region of the human BMP-2 gene was constructed and transfected into human osteosarcoma (HOS) cells. By the screening of an in-house natural product library with stably transfected HOS cells, a fungal metabolite, compactin, known as an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, was isolated. The stimulation of the promoter activity by compactin seemed to be specific for BMP-2 gene in HOS cells, since it had little effect on BMP-4 or SV40 promoter activity and the stimulation was not observed in Chinese hamster ovary (CHO) cells. RT-PCR analysis and alkaline phosphatase assay revealed that compactin induced an increase in the expression of BMP-2 mRNA and protein. Like compactin, simvastatin also activated the BMP-2 promoter, whereas pravastatin did not. The statin-mediated activation of BMP-2 promoter was completely inhibited by the downstream metabolite of HMG-CoA reductase, mevalonate, indicating that the activation was a result of the inhibition of the enzyme. These results suggest that statins, if they are selectively targeted to bone, have beneficial effects in the treatment of osteoporosis or bone fracture.

Topics: Anti-Bacterial Agents; Bone Morphogenetic Protein 2; Bone Morphogenetic Protein 4; Bone Morphogenetic Proteins; Bone Neoplasms; Cloning, Molecular; Disulfides; Enzyme Inhibitors; Gene Expression Regulation, Neoplastic; Genes, Reporter; Humans; Indole Alkaloids; Lovastatin; Mevalonic Acid; Osteoporosis; Osteosarcoma; Pravastatin; Promoter Regions, Genetic; RNA, Messenger; Simvastatin; Transfection; Transforming Growth Factor beta; Tumor Cells, Cultured

Osteoporosis and osteoarthritis each exhibit a strong genetic component. Although polymorphisms of a variety of genes have been associated with bone mineral density and genetic susceptibility to osteoporosis or to osteoarthritis, the genes responsible for these conditions have not been definitively identified. We have shown that a T(869)-->C polymorphism of the transforming growth factor-beta1 (TGF-beta1) gene, which results in a Leu-->Pro substitution at amino acid 10, is associated with bone mineral density in Japanese adolescents and postmenopausal women, with genetic susceptibility to osteoporosis or spinal osteoarthritis, and with the outcome of treatment for osteoporosis with active vitamin D. I here review our recent studies, which have provided insight into the function of TGF-beta1 as well as into the role of genetic factors in the development of osteoporosis and osteoarthritis.

Topics: Animals; Bone Density; Disease Susceptibility; Genetic Predisposition to Disease; Genotype; Humans; Leucine; Osteoarthritis; Osteoporosis; Polymorphism, Genetic; Proline; Radius; Transforming Growth Factor beta; Transforming Growth Factor beta1; Treatment Outcome

Topics: Aged; Bone Density; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Confounding Factors, Epidemiologic; Female; Hip Fractures; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Osteoporosis; Transforming Growth Factor beta

Regular blood transfusions from infancy until adulthood in beta-thalassaemia major patients have substituted severe bone deformities with less marked skeletal lesions as osteoporosis. Osteoporosis is characterized by low bone mass and disruption of bone architecture, resulting in reduced bone strength and increased risk of fractures. Genetic factors have an important role in determining bone mineral density (BMD). We have investigated the possible association between BMD and two polymorphisms in 135 beta-thalassaemic patients: (i) a substitution G-->Tau in a regulatory region of the COLIA1 gene encoding for the major protein of bone (type 1 collagen), and (ii) a one-base deletion in intron 4 (713-8del C) of transforming growth factor beta 1 (TGF-beta1) gene. We have found a remarkable incidence (90%) of osteopenia and osteoporosis among regularly transfused patients. Bone mass was lower in men than in women (P = 0.0023), with a more prevalent osteopenia/osteoporosis of the spine in men than in women (P = 0. 001). The sample was stratified on the basis of BMD expressed as Z-score, i.e. normal, osteopenic and osteoporotic patients, and genotype frequencies of each group were evaluated. TGF-beta1 polymorphism failed to demonstrate a statistical difference in BMD groups. However, subjects with heterozygous or homozygous polymorphism of the COLIA1 gene showed a lower BMD than subjects without the sequence variation (P = 0.012). The differences among genotypes were still present when the BMD was analysed as adjusted Z-score and when men and women were analysed separately (P = 0.022 and 0.004 respectively), with men more severely affected. Analysis of COLIA1 polymorphism could help to identify those thalassaemic patients at risk of osteoporosis and fractures.

Topics: Adult; Analysis of Variance; beta-Thalassemia; Bone Density; Collagen; Female; Gene Deletion; Genotype; Humans; Male; Osteoporosis; Polymorphism, Genetic; Regression Analysis; Transforming Growth Factor beta; Transfusion Reaction

Bone morphogenetic proteins (BMPs) are capable of inducing endochondral bone formation when applied on biologic carriers in numerous mammalian in vivo assay systems. Bone morphogenetic protein gene therapy is also currently being developed to promote osteogenesis for clinical indications such as spinal fusions, craniofacial bone loss, and osteoporosis. In this study, critical-sized mandibular defects were treated with a control adenoviral vector (Ad-beta-gal), a BMP-2 adenoviral vector (Ad-BMP-2), or a BMP-9 adenoviral vector (Ad-BMP-9). Gross tissue examination, radiographic analysis, and histologic analysis demonstrated significant bony healing in the BMP treated groups compared to controls. Osteogenesis was limited to the bony defect, without extension into the surrounding soft tissues. The study suggests that with further development, BMP gene therapy may be potentially useful for repair of bony defects in the craniofacial region.

Topics: Animals; beta-Galactosidase; Bone Marrow; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Bone Regeneration; Cytomegalovirus; Follow-Up Studies; Genetic Therapy; Genetic Vectors; Growth Differentiation Factor 2; Image Processing, Computer-Assisted; Mandible; Mandibular Diseases; Osteogenesis; Osteoporosis; Rats; Rats, Nude; Spinal Fusion; Tomography, X-Ray Computed; Transforming Growth Factor beta; Wound Healing

Osteoporosis and other diseases of bone loss are a major public health problem. Here it is shown that the statins, drugs widely used for lowering serum cholesterol, also enhance new bone formation in vitro and in rodents. This effect was associated with increased expression of the bone morphogenetic protein-2 (BMP-2) gene in bone cells. Lovastatin and simvastatin increased bone formation when injected subcutaneously over the calvaria of mice and increased cancellous bone volume when orally administered to rats. Thus, in appropriate doses, statins may have therapeutic applications for the treatment of osteoporosis.

Topics: Animals; Bone Density; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Cell Line; Female; Fibroblast Growth Factor 1; Fibroblast Growth Factor 2; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Lovastatin; Male; Mice; Mice, Inbred ICR; Organ Culture Techniques; Osteoblasts; Osteoclasts; Osteogenesis; Osteoporosis; Ovariectomy; Promoter Regions, Genetic; Rats; Recombinant Proteins; Simvastatin; Skull; Transfection; Transforming Growth Factor beta

Topics: Animals; Anticholesteremic Agents; Bone Density; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Clinical Trials as Topic; Female; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Lovastatin; Mice; Osteogenesis; Osteoporosis; Rats; Simvastatin; Transforming Growth Factor beta

Currently, primary osteoporosis is the most frequent metabolic disease in women after menopause [1]. The resulting loss of bone mass is accompanied by an increased risk of skeletal fragility. One reason for the development of osteoporosis might be an impaired function of mature osteoblasts. To evaluate the involvement of specific growth factors in bone remodeling, cell cultures of osteoblastic cells derived from nonosteoporotic and osteoporotic postmenopausal women were established. The influences of TGF beta-1 and IGF-I on proliferation and mRNA expression of TGF beta-1 were investigated by [3H]-thymidine incorporation and competitive RT-PCR. We found IGF-I to have no significant effect on proliferation in cells of osteoporotic and nonosteoporotic patients. In contrast, differences were found in TGF beta-1 mRNA expression after application of IGF-I. Application of TGF beta-1 enhanced its own mRNA expression in both groups in a similar manner. Whereas the proliferation of cells of nonosteoporotic patients was inhibited by (10(-10) M) TGF beta-1, this treatment led to an increased proliferation of cells of osteoporotic patients.

Topics: Aged; Aged, 80 and over; Binding, Competitive; Cell Division; Cells, Cultured; Female; Femur; Humans; Insulin-Like Growth Factor I; Middle Aged; Osteoblasts; Osteoporosis; Polymerase Chain Reaction; RNA, Messenger; Transforming Growth Factor beta

Bone adapts to mechanical stress, and bone cell cultures from animal origin have been shown to be highly sensitive to mechanical stress in vitro. In this study, we tested whether bone cell cultures from human bone biopsies respond to stress in a similar manner as animal bone cells and whether bone cells from osteoporotic patients respond similarly to nonosteoporotic donors. Bone cell cultures were obtained as outgrowth from collagenase-stripped trabecular bone fragments from 17 nonosteoporotic donors between 7 and 77 yr of age and from 6 osteoporotic donors between 42 and 72 yr of age. After passage, the cells were mechanically stressed by treatment with pulsating fluid flow (PFF; 0.7 +/- 0.03 Pa at 5 Hz for 1 h) to mimic the stress-driven flow of interstitial fluid through the bone canaliculi, which is likely the stimulus for mechanosensation in bone in vivo. Similar to earlier studies in rodent and chicken bone cells, the bone cells from nonosteoporotic donors responded to PFF with enhanced release of prostaglandin E2 (PGE2) and nitric oxide as well as a reduced release of transforming growth factor-beta (TGF-beta). The upregulation of PGE2 but not the other responses continued for 24 h after 1 h of PFF treatment. The bone cells from osteoporotic donors responded in a similar manner as the nonosteoporotic donors except for the long-term PGE2 release. The PFF-mediated upregulation of PGE2 release during 24 h of postincubation after 1 h of PFF was significantly reduced in osteoporotic patients compared with six age-matched controls as well as with the whole nonosteoporotic group. These results indicate that enhanced release of PGE2 and nitric oxide, as well as reduced release of TGF-beta, is a characteristic response of human bone cells to fluid shear stress, similar to animal bone cells. The results also suggest that bone cells from osteoporotic patients may be impaired in their long-term response to mechanical stress.

Topics: Adolescent; Adult; Aged; Bone and Bones; Cells, Cultured; Child; Dinoprostone; Female; Humans; Male; Middle Aged; Nitric Oxide; Osteoporosis; Periodicity; Rheology; Stress, Mechanical; Transforming Growth Factor beta

Topics: Bone Density; Collagen; Female; Fractures, Spontaneous; Genetic Markers; Genotype; Humans; Interleukin-6; Male; Osteoporosis; Polymorphism, Genetic; Receptors, Calcitriol; Receptors, Estrogen; Risk Assessment; Transforming Growth Factor beta

Transforming growth factor-beta (TGF-beta) is both abundant in bone and an important regulator of bone metabolism. A T-->C transition at nucleotide 29 in the signal sequence region of the TGF-beta1 gene results in a Leu-->Pro substitution at amino acid position 10. The possible association of this polymorphism with bone mass and the prevalence of osteoporosis has now been investigated in a total of 287 postmenopausal women from two regions (Obu City, Aichi Prefecture, and Sanda City, Hyogo Prefecture) of Japan. A significant association of TGF-beta1 genotype with bone mass was detected in both populations; bone mineral density (BMD) at the lumbar spine was greater in individuals with the CC genotype than in those with the TT or TC genotype. The frequency of vertebral fractures was significantly lower in individuals with the CC genotype than in those with the TC or TT genotypes. For each region, multivariable logistic regression analysis revealed that the frequency of the T allele was significantly higher in subjects with osteoporosis than in controls. Also, the serum concentration of TGF-beta1 in individuals with the CC genotype was significantly higher than that in age-matched subjects with the TC or TT genotype in osteoporotic or osteopenic as well as healthy control groups. These results suggest that the T/C polymorphism of the TGF-beta1 gene is one of the genetic determinants of bone mass and that the T allele is an independent risk factor for the genetic susceptibility to osteoporosis in postmenopausal Japanese women. Thus, analysis of the TGF-beta1 genotype may be useful in the prevention and management of osteoporosis.

Topics: Adult; Aged; Amino Acid Substitution; Female; Genetic Predisposition to Disease; Genotype; Humans; Japan; Leucine; Middle Aged; Osteoporosis; Polymorphism, Genetic; Postmenopause; Proline; Protein Sorting Signals; Sequence Analysis, DNA; Transforming Growth Factor beta

Bone mass is partly genetically determined. The genes involved are, however, still largely unknown. Transforming growth factor-beta 1 (TGF-beta 1) is considered a putative regulator of osteoclastic-osteoblastic interaction (coupling). The aim of the present study was therefore to examine whether possible variants of the TGF-beta 1 gene are related to bone mass and osteoporosis. We examined 161 osteoporotic women (at least one low energy spinal fracture) and 131 normal women. We investigated sequence variations in the TGF-beta 1 gene using the single-stranded conformation polymorphism (SSCP) technique combined with DNA sequencing. Seven patients were heterozygous for a cytosine to thymidine base substitution at position 76 in exon 5 (C788-T) (corresponding to position 788 in the TGF-beta 1 cDNA), resulting in a threonine to isoleucine amino acid shift at position 263 in the TGF-beta 1 propeptide (Thr263-Ile). Ten other patients had a one base deletion in the intron sequence 8 bases prior to exon 5 (713-8delC), which could influence splicing. Five normal women exhibited the C788-T sequence variant, and two the 713-8delC. The prevalence of 713-8delC was significantly higher in the osteoporotic group (chi 2 = 4.02, p < 0.05). Osteoporotic patients with the 713-8delC variant had increased levels of bone alkaline phosphatase (p < 0.05). If the osteoporotic patients with a z score of the lumbar spine below -1 were examined separately, we found increased serum levels of bone alkaline phosphatase (p < 0.05), increased urinary excretion of hydroxyproline (p < 0.05), and reduced bone mass of the lumbar spine (p < 0.05) in patients with 713-8delC. No correlation to bone mass was demonstrated in the normal women, but 713-8delC was associated with increased serum levels of bone alkaline phosphatase (p < 0.05). The sequence variation, 713-8delC, in the TGF-beta 1 gene is more frequent in patients with osteoporosis compared to normal controls. The 713-8delC variant seems to be associated with very low bone mass in osteoporotic women with low bone mass and increased bone turnover in both osteoporotic and normal women.

Topics: Adult; Aged; Aged, 80 and over; Bone Density; DNA Primers; Exons; Female; Genetic Variation; Humans; Middle Aged; Osteoporosis; Polymerase Chain Reaction; Polymorphism, Genetic; Polymorphism, Single-Stranded Conformational; Sequence Analysis, DNA; Transforming Growth Factor beta

The development of the skeleton requires the coordinated activities of bone-forming osteoblasts and bone-resorbing osteoclasts. The activities of these two cell types are likely to be regulated by TGF-beta, which is abundant in bone matrix. We have used transgenic mice to evaluate the role of TGF-beta 2 in bone development and turnover. Osteoblast-specific overexpression of TGF-beta 2 from the osteocalcin promoter resulted in progressive bone loss associated with increases in osteoblastic matrix deposition and osteoclastic bone resorption. This phenotype closely resembles the bone abnormalities seen in human hyperparathyroidism and osteoporosis. Furthermore, a high level of TGF-beta 2 overexpression resulted in defective bone mineralization and severe hypoplasia of the clavicles, a hallmark of the developmental disease cleidocranial dysplasia. Our results suggest that TGF-beta 2 functions as a local positive regulator of bone remodeling and that alterations in TGF-beta 2 synthesis by bone cells, or in their responsiveness to TGF-beta 2, may contribute to the pathogenesis of metabolic bone disease.

Topics: Age Factors; Animals; Base Sequence; Bone and Bones; Bone Remodeling; Bone Resorption; Calcification, Physiologic; Clavicle; Immunohistochemistry; Mice; Mice, Inbred C57BL; Mice, Inbred DBA; Mice, Transgenic; Molecular Sequence Data; Osteoblasts; Osteocalcin; Osteoclasts; Osteoporosis; Phenotype; Promoter Regions, Genetic; Recombinant Fusion Proteins; Transforming Growth Factor beta

The osteopenia associated with advanced age appears to be a universal phenomenon in humans and animals, but the mechanisms by which it occurs are understood incompletely. However, the explanation must lie in an absolute or relative diminution in the level of osteoblastic bone-forming activity when compared with osteoclastic bone-resorbing activity. The authors postulated that with old age there would be a reduction in the number or function or both of osteoblastic stem cells that could account for part of the diminution in bone formation. They further postulated that there would be either no change or an increase in osteoclastic potential and bone resorption. To test these concepts, bone marrow cells were isolated from 4- to 6-month-old or 24-month-old mice and cultured in vitro under a variety of circumstances that permitted an assessment of the stromal osteogenic cells and marrow hemopoietic progenitor cells belonging to the monocyte and osteoclast series. These data show a marked reduction in the number and in vitro activity of stromal osteogenic cells from old animals. There is an increase in old mice in the number of marrow cells capable of forming osteoclasts in coculture and responsive to the growth factors believed operational in the monocyte and osteoclast series. The authors now are exploring the hypothesis that an age-related diminution in transforming growth factor-beta levels is responsible for these changes in progenitor cell levels in marrow and their functional status as expressed in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Aging; Animals; Bone Marrow; Cell Count; Cells, Cultured; Colony-Forming Units Assay; Hematopoietic Stem Cells; Male; Mice; Mice, Inbred BALB C; Osteoblasts; Osteoclasts; Osteoporosis; Stem Cells; Transforming Growth Factor beta

We previously reported that bone marrow stromal cells produce insulin-like growth factors (IGF-I and -II), and that medium conditioned by marrow stromal cells stimulates osteoblast proliferation in vitro. The present study employed the rat tail-suspension model to unload the hindlimbs. It was designed to test the hypothesis that the development of osteopenia or osteoporosis could be due to a deficit in the osteogenic function of marrow stromal cells. Although tail suspension suppressed body weight during the first 3 days of an 11-day pair-fed study, the overall weight gain recorded by these animals was normal. Nevertheless, bone growth was inhibited by suspension. Similarly, the total adherent marrow stromal cell population harvested from the femurs and tibias was decreased by tail suspension, and only half the normal number of fibroblastic stromal cell colonies grew when they were cultured. The proliferation of alkaline-phosphatase-positive cells in the stroma was also inhibited. Northern hybridization revealed that the messenger RNA level for transforming growth factor-beta 2 and IGF-II in stromal cell was reduced by tail suspension. The production of IGF-II by marrow stromal cells was also decreased. The steady-state level of five different transcript sizes of IGF-I mRNA was altered differentially by tail suspension. Osteopontin mRNA was also reduced in marrow stromal cells from tail-suspended rats compared with the normal rats. These data suggest that skeletal unloading not only alters the mRNA level for growth factors and peptide production, but also affects the proliferation and osteogenic differentiation of marrow stromal cells. These changes may be responsible for the reduced bone formation in osteopenia and osteoporosis.

Topics: Animals; Bone Diseases, Metabolic; Bone Marrow Cells; Cell Adhesion; Cell Differentiation; Cell Division; Cells, Cultured; Collagen; Femur; Gene Expression Regulation, Developmental; Male; Osteoblasts; Osteogenesis; Osteopontin; Osteoporosis; Random Allocation; Rats; Rats, Wistar; RNA, Messenger; Sialoglycoproteins; Somatomedins; Stromal Cells; Tail; Tibia; Transforming Growth Factor beta; Weight-Bearing

Mechanical stimulation of bone tissue by physical activity stimulates bone formation in normal bone and may attenuate bone loss of osteoporotic patients. However, altered responsiveness of osteoblasts in osteoporotic bone to mechanical stimuli may contribute to osteoporotic bone involution. The purpose of the present study was to investigate whether osteoblasts from osteoporotic patients and normal donors show differences in proliferation and TGF beta production in responses to cyclic strain. Human osteoblasts isolated from collagenase-treated bone explants of 10 osteoporotic patients (average age 70 +/- 6 yr) and 8 normal donors (average age 54 +/- 10 yr) were plated into elastic rectangular silicone dishes. Subconfluent cultures were stimulated by cyclic strain (1%, 1 Hz) in electromechanical cell stretching apparatus at three consecutive days for each 30 min. The cultures were assayed for proliferation, alkaline phosphatase activity and TGF beta release in each three parallel cultures. In all experiments, osteoblasts grown in the same elastic dishes but without mechanical stimulation served as controls. Significant differences between stimulated cultures and unstimulated controls were determined by a paired two-tailed Wilcoxon test. In comparison to the unstimulated controls, osteoblasts from normal donors significantly increased proliferation (p = 0.025) and TGF beta secretion (p = 0.009) into the conditioned culture medium. In contrast, osteoblasts from osteoporotic donors failed to increase both proliferation (p > 0.05) and TGF beta release (p > 0.05) in response to cyclic strain. Alkaline phosphatase activity was not significantly affected (p > 0.05) in normal as well as osteoporotic bone derived osteoblasts. These findings suggest a different responsiveness to 1% cyclic strain of osteoblasts isolated from normal and osteoporotic bone that could be influenced by both the disease of osteoporosis and the higher average age of the osteoporotic patient group. While osteoblasts from osteoporotic donors failed to increase proliferation and TGF beta release under the chosen mechanical strain regimen that stimulated both parameters in normal osteoblasts, it is possible that some other strain regimen would provide more effective stimulation of osteoporotic cells.

Topics: Age Factors; Aged; Aged, 80 and over; Alkaline Phosphatase; Biomechanical Phenomena; Cell Division; Cells, Cultured; Culture Media, Conditioned; Female; Humans; Male; Middle Aged; Osteoblasts; Osteoporosis; Stress, Mechanical; Transforming Growth Factor beta

Calvarial bone grafts may have greater survival as donor tissue than bone from other sites. Furthermore, calvarial bone is resistant to osteoporosis. Because bone contains growth factors that may play an important role in the regulation of bone repair, we proposed that bone from calvaria may be enriched in one or more growth factors. To test this hypothesis, samples of bone from 10 men 64 years of age or older that were obtained at autopsy from three skeletal sites (calvaria, iliac crest, and vertebral body) were cleaned, extracted by demineralization, and assayed for growth factors insulin-like growth factor I, insulin-like growth factor II, and transforming growth factor-beta. Insulin-like growth factor II and transforming growth factor-beta concentrations were significantly higher in calvaria than in iliac crest or vertebral body. We conclude that the increased concentrations of growth factors in calvarial bone may lead to a greater capacity for bone repair and graft retention.

Topics: Aged; Bone Transplantation; Cadaver; Graft Survival; Humans; Ilium; Insulin-Like Growth Factor I; Insulin-Like Growth Factor II; Male; Middle Aged; Osteoporosis; Skull; Spine; Transforming Growth Factor beta

We determined the skeletal content of insulin-like growth factor-I (IGF-I) and transforming growth factor-beta (TGF beta) in human bone as a function of age, using 66 samples of femoral cortical bone obtained from 46 men and 20 women between the ages of 20-64 yr. We found a linear decline in the skeletal content of IGF-I (nanograms per mg protein) with donor age (r = -0.43; P < 0.001) in the total population. The skeletal content of TGF beta also decreased with age (i.e. 1/TGF beta vs. age; r = 0.28; P < 0.02) for the total population. We did not observe any difference in the skeletal growth factor content between male and female donors. IGF-I content, when analyzed by decade divisions of age, showed a reduction between the 20- to 29-yr-old and the 50- to 59-yr-old subjects (P < 0.02). The loss rate of IGF-I was 1.56 ng/mg protein.yr, corresponding to a net loss of 60% of skeletal IGF-I between the ages of 20-60 yr. The loss rate of TGF beta was 0.03 ng/mg protein.yr, corresponding to a net loss of 25% of the skeletal TGF beta between the ages of 20-60 yr.

Topics: Adult; Aging; Female; Femur; Humans; Insulin-Like Growth Factor I; Male; Middle Aged; Osteoporosis; Transforming Growth Factor beta

To investigate whether growth factors stored in bone might explain the increased bone density and resistance to osteoporosis in generalized osteoarthritis.. Levels of insulin-like growth factor (IGF) types I and II and transforming growth factor beta (TGF beta) were measured in extracts of cortical bone from the iliac crest obtained at necropsy from subjects with or without osteoarthritis of the hands.. Concentrations of IGF-I, IGF-II, and TGF beta were significantly higher in extracts of bone powder from subjects in the osteoarthritis group than in extracts from subjects in the control group.. The results suggest that the increased bone density and resistance to osteoporosis in patients with osteoarthritis may be associated with increased skeletal concentrations of IGF-I, IGF-II, and TGF beta and may reflect a generally increased biosynthetic activity of osteoblasts in these patients.

Topics: Aged; Bone Density; Female; Hand; Humans; Ilium; Insulin-Like Growth Factor I; Insulin-Like Growth Factor II; Osteoarthritis; Osteoporosis; Radiography; Transforming Growth Factor beta

We have shown previously that the decreased trabecular bone formation in osteoporotic postmenopausal women results from a reduced ability of osteoblastic cells to proliferate. In this study we have tested the possibility that bone cells from osteoporotic women with low bone formation have an abnormal responsiveness to hormonal or local mitogenic factors. Primary cultures of bone cells with osteoblastic characteristics were obtained by migration from the trabecular bone surface in osteoporotic postmenopausal women with high (n = 7) or low (n = 7) bone formation as evaluated histomorphometrically by the extent of double tetracycline-labeled surface (DLS). Control bone cells were obtained under identical conditions from eight normal age-matched postmenopausal women. Parameters of osteoblastic differentiation (alkaline phosphatase activity and osteocalcin production) were found to be normal and similar in bone cells from osteoporotic women with low or high DLS. In contrast, cell replication as evaluated by [3H]thymidine into DNA was 3.4-fold lower in the low DLS group compared to the high DLS group, confirming our previous findings. Treatment of quiescent bone cells with TGF-beta (0.5-1 ng/ml) for 24 h significantly stimulated DNA synthesis in osteoblastic cells from normal women and in bone cells from osteoporotic patients with low or high DLS, indicating a normal responsiveness to TGF-beta in these patients. We have compared the effect of parathyroidhormone (PTH) on bone cells from normal and osteoporotic women. Basal cAMP levels and the cAMP accumulation in response to (1-34)-hPTH were similar in bone cells from patients with low or high DLS and were not different from normal values.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Aged; Bone and Bones; Cell Division; Cyclic AMP; Dinoprostone; DNA; Female; Humans; Middle Aged; Osteoblasts; Osteoporosis; Parathyroid Hormone; Transforming Growth Factor beta