transforming-growth-factor-beta and Osteoporosis--Postmenopausal

The primary goal of treatment for postmenopausal osteoporosis is the reduction in fracture risk. Bisphosphonates have long been established as first-line therapy for osteoporosis and several of these drugs significantly reduce osteoporotic fracture risk. Alendronate, risedronate, ibandronate and zoledronic acid all provide fracture protection for patients with postmenopausal osteoporosis. All four agents have demonstrated efficacy in preventing vertebral fractures, but only zoledronic acid and risedronate significantly reduce non-vertebral fracture risk in pivotal trials. Moreover, reduction in hip fracture risk has been established for alendronate, risedronate and zoledronic acid. Ibandronate and zoledronic acid have the most persistent antifracture effect. Bisphosphonates have been associated with a number of side effects, with a well-documented association between gastrointestinal adverse events and oral administration, and between acute phase reactions and intravenous administration.

Topics: Bisphosphonate-Associated Osteonecrosis of the Jaw; Diphosphonates; Female; Fractures, Spontaneous; Humans; Osteoporosis, Postmenopausal; Transforming Growth Factor beta

Recent studies have suggested a possible role of T-cells and tumor necrosis factor-alpha (TNF-alpha) in the pathogenesis of bone loss which occurs in systemic inflammatory diseases. The relevance of T-cells activity in bone loss due to estrogen deficiency has been investigated in recent years by Dr. Pacifici's group. They have shown that the increased presence of TNF-alpha producing T-cells is essential for the changes in bone metabolism during estrogen deficiency. Lack of estrogen increases interferon-y (INF-y) production by helper T-cells, which through complex class II an increased expression of major histocompatibility complex class II (MCHII) on antigen presenting cells, enhances the activation and proliferation of TNF-alpha producing T-cells. The protective role of estrogen on bone loss is mediated by type beta transforming growth factor (TGF-beta), which blocks T-cell activation and T-cell TNF-alpha production by repressing antigen presentation.

Topics: Aged; Aged, 80 and over; Animals; Autoimmune Diseases; Bone and Bones; Disease Models, Animal; Estrogens; Female; Histocompatibility Antigens Class II; Humans; Lymphocyte Activation; Major Histocompatibility Complex; Middle Aged; Osteoporosis, Postmenopausal; T-Lymphocytes; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha

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

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-beta 1 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 here review the association of transforming growth factor-beta 1 gene polymorphisms with genetic susceptibility to osteoporosis, which has provided insight into the function of transforming growth factor-beta 1 as well as into the role of genetic factors in the development of osteoporosis.

Topics: Adolescent; Aged; Bone Density; Bone Remodeling; Female; Genetic Predisposition to Disease; Genotype; Humans; Osteoporosis, Postmenopausal; Polymorphism, Genetic; Transforming Growth Factor beta; Transforming Growth Factor beta1; Vitamin D

Topics: Bone Remodeling; Cell Differentiation; Cytokines; Estrogens; Female; Humans; Middle Aged; Osteoblasts; Osteoporosis, Postmenopausal; Risk Factors; Transforming Growth Factor beta

Topics: Animals; Bone Resorption; Estrogens; Humans; Insulin-Like Growth Factor I; Interleukin-1; Osteoporosis, Postmenopausal; Transforming Growth Factor beta

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

Over the last few years, conclusive evidence of the involvement of the immune system in the regulation of bone metabolism has been identified. Consequently, one question that should be formulated concerns the possible effects of antiresorptive therapies on the immune system. Therefore, the purpose of the present work was to evaluate both the functionality of the immune system and bone turnover in women receiving antiresorptive therapies, such as hormone therapy (HT; n = 33) and raloxifene (RLX; n = 66), acting through estrogen receptors.. To that end, this study analyzed bone turnover markers in a population of postmenopausal women before and after beginning therapy and compared these with data of women not treated (NT; n = 102). In a subgroup of participants (NT = 33, RLX = 24, and HT = 26), we analyzed the effects of treatments on immune system parameters such as serum levels of interleukin (IL)-6, tumor necrosis factor α, and IL-1β; lymphocyte subpopulations; cell proliferation by peripheral blood mononuclear cells (PBMCs); in vitro production of IL-1β by PBMCs; and the expression of receptor activator of nuclear factor-κB ligand, transforming growth factor β, and IL-4 genes by PBMCs.. The results showed that bone resorption was inhibited strongly in women in the RLX and HT groups when compared with women in the NT group. Interestingly, the administration of RLX inhibited the production of the Wnt/β-catenin signaling pathway inhibitor Dickkopf Homolog-1 (P < 0.05) and tended to increase the levels of the osteoclastogenesis inhibitor osteoprotegerin at month 6 (P = 0.059). With regard to the immune system, the different treatments did not markedly perturb the parameters analyzed, with the exception of the increase in serum IL-1β detected in the HT group at month 6 (P < 0.05).. The main conclusions of the present work were that HT or RLX do not disturb the immune system and that both treatments have a similar antiresorptive power.

Topics: Bone Density Conservation Agents; Bone Remodeling; Cell Proliferation; Cells, Cultured; Female; Humans; Intercellular Signaling Peptides and Proteins; Interleukin-1beta; Interleukin-4; Interleukin-6; Leukocytes, Mononuclear; Lymphocyte Subsets; Middle Aged; Osteoporosis, Postmenopausal; Osteoprotegerin; Raloxifene Hydrochloride; Receptor Activator of Nuclear Factor-kappa B; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha

The relationship between transforming growth factor β superfamily members (GDF11 and BMP4) and bone metabolism remains controversial. The aim of this study was to investigate the association between serum GDF11 and BMP4 levels and lumbar spine bone mineral density (LBMD) in a cohort of postmenopausal Chinese women.. This was a non-prospective cross-sectional study of 350 postmenopausal women with a mean age of 63.13 ± 8.66 years who came from Shenyang, China. LBMD was measured using dual-energy X-ray absorptiometry. Serum GDF11 and BMP4 concentrations were detected using a sandwich enzyme immunoassay kit. Pearson's correlation analysis and regression analyses were carried out to investigate the relationships between LBMD and serum GDF11 and BMP4 levels.. A linear association between LBMD and serum LgGDF11 concentration was observed after adjusting for numerous confounders (P = 0.018). In addition, the osteoporosis (OP) was inversely related to LgGDF11 and the odds ratios for postmenopausal women with lumbar OP in LgGDF11 quartile group 2, group 3, and group 4 were 0.46 (95% CI 0.23-0.90, P < 0.05), 0.41 (95% CI 0.20-0.84, P < 0.05), and 0.30 (95% CI 0.14-0.63, P < 0.01), respectively (P = 0.001 for the trend), when compared to the highest quartile of LgGDF11 after adjustments for many confounding variables in this study.. This study showed that serum GDF11 levels were linearly related to LBMD, and it was also revealed that serum GDF11 levels were significantly associated with lumbar OP in postmenopausal women. However, serum BMP4 levels were not associated with LBMD and lumbar OP.

Topics: Absorptiometry, Photon; Aged; Bone Density; Bone Morphogenetic Protein 4; Bone Morphogenetic Proteins; Cross-Sectional Studies; Female; Growth Differentiation Factors; Humans; Lumbar Vertebrae; Middle Aged; Osteoporosis, Postmenopausal; Postmenopause; Transforming Growth Factor beta

Teriparatide is a bone anabolic treatment for osteoporosis, modeled in animals by intermittent PTH (iPTH) administration, but the cellular and molecular mechanisms of action of iPTH are largely unknown. Here, we show that Teriparatide and iPTH cause a ~two-threefold increase in the number of regulatory T cells (Tregs) in humans and mice. Attesting

Topics: Aged; Animals; Biomarkers; Bone Density Conservation Agents; Calcium; Calcium-Regulating Hormones and Agents; Collagen Type I; Core Binding Factor Alpha 1 Subunit; Disease Models, Animal; Female; Gene Expression; Humans; Integrin-Binding Sialoprotein; Lymphocyte Count; Mice; Osteocalcin; Osteoporosis, Postmenopausal; Ovariectomy; Sp7 Transcription Factor; T-Lymphocytes, Regulatory; Teriparatide; Transforming Growth Factor beta; Treatment Outcome; Vitamin D

Postmenopausal osteoporosis (OPM) is a common type of osteoporosis in females. It is a systemic, chronic bone disease that presents as microstructure degradation of osseous tissue, decreased bone mineral density and increased osteopsathyrosis caused by hypoovarianism and reduced estrogen levels in the body following menopause. In the present study, the role of microRNA (miR)‑214‑5p in the regulation of the expression of bone marrow stem cells (BMSCs) was investigated, and its molecular mechanism of osteogenic induction in vitro was assessed. When dexamethasone‑induced adipogenic differentiation was performed, miR‑214‑5p expression was increased compared with the control group, as determined by RT‑qPCR. Furthermore, oil red O staining, RT‑qPCR and western blot analysis demonstrated that overexpression of miR‑214‑5p promoted adipogenic differentiation, inhibited alkaline phosphatase (ALP), runt‑related transcription factor 2 (Runx2), osteocalcin (OC) and collagen α‑1 (I) chain (COL1A1) mRNA expression, and suppressed transforming growth factor (TGF)‑β, phosphorylated (p)‑Smad2 and collagen type IV α1 chain (COL4A1) protein expression in BMSCs. Additionally, downregulation of miR‑214‑5p increased the ALP, Runx2, OC and COL1 mRNA expression and increased TGF‑β, Smad2 and COL4A1 protein expression in BMSCs. Furthermore, a TGF‑β inhibitor was employed to inhibit TGF‑β expression in BMSCs following miR‑214‑5p downregulation, which led to reduced Smad2, TGF‑β and COL4A1 protein expression, and ALP, Runx2, OC and COL1 mRNA expression was also reduced, compared with the miR‑214‑5p downregulation only group. It was demonstrated that miR‑214‑5p may weaken osteogenic differentiation of BMSCs through regulating COL4A1. In conclusion, the results of the present study indicated that miR‑214‑5p may promote the adipogenic differentiation of BMSCs through regulation of the TGF‑β/Smad2/COL4A1 signaling pathway, and potentially may be used to develop a novel drug for postmenopausal osteoporosis.

Topics: Adipogenesis; Cell Differentiation; Cell Line; Female; Humans; MicroRNAs; Osteoporosis, Postmenopausal; Signal Transduction; Smad2 Protein; Stem Cells; Transforming Growth Factor beta

Postmenopausal osteoporosis (PMO) is the most common metabolic bone disease in women after menopausal. Recent works focused on cross—talk between immune regulation and bone metabolism pathways and suggested Treg cells suppressed bone resorption and osteoclasts (OC) differentiation in bone marrow via cell—cell contact interaction and/or secreting of IL—10 and TGF—beta. In this study, we investigated the impact of estrogen on regulatory T cells (Treg cells) trafficking and staying in bone marrow and we found that a significant reduction of Treg cell population in bone marrow in estrogen deficiency ovariectomied (OVX) mice. We then studied the expressions of chemokines CXCL12/CXCR4 axes, which were critical to Treg cells migration and our data show the expression of CXCR4 on Treg cells was relative with oestrogen in vivo, however, the expression of CXCL12 was not. Furthermore, the loss of trafficking ability of Treg cells in OVX mice was recoverable in our system. These findings may mechanistically explain why Treg cells lose their suppressive functions on the regulation of OC cells and demonstrate a previously unappreciated role for estrogen, which may be critical to the novel therapy in clinical practice of PMO patients.

Topics: Animals; Bone and Bones; Bone Marrow; Bone Marrow Cells; Bone Resorption; Cell Differentiation; Cells, Cultured; Chemokine CXCL12; Down-Regulation; Estrogens; Humans; Interleukin-10; Mice; Osteoclasts; Osteoporosis, Postmenopausal; Ovariectomy; Receptors, CXCR4; T-Lymphocytes, Regulatory; Transforming Growth Factor beta

Qing'e formula (QEF), prepared from an ancient Chinese recipe, was previously suggested to regulate bone metabolism and improve bone mineral density in patients with osteoporosis. To study the effects of medicated serum containing QEF on the in vitro differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) isolated from the proximal femurs of postmenopausal osteoporosis (PMOP) mice.. Using an established mouse model of PMOP, mononuclear cells were isolated from the bone marrow present in the proximal femurs and cultured. PMOP mice were also randomly divided into four groups: the untreated group (Group A) and the groups treated with respectively low (Group B), medium (Group C), and high (Group D) concentrations of QEF. Serum was isolated from each and used to treat the cultured BMSCs in conjunction with recombinant human bone morphogenetic protein-2 (rhBMP-2). Cell morphology, proliferation rates, intracellular alkaline phosphatase (ALP) activity, and transforming growth factor-beta 1 (TGF-β1) mRNA expression were evaluated.. QEF-treated serum, particularly that containing moderate and high concentrations, appears to enhance the rhBMP-2-mediated changes in cell morphology, proliferation, and differentiation (determined via the expression of TGF-β1 mRNA and ALP activity) observed in the BMSCs isolated from PMOP mice.. QEF may play a role in the prevention and treatment of PMOP by enhancing the activity of rhBMP-2.

Topics: Alkaline Phosphatase; Animals; Bone Marrow; Bone Marrow Cells; Bone Morphogenetic Protein 2; Cell Differentiation; Cell Proliferation; Cells, Cultured; Drugs, Chinese Herbal; Female; Femur; Humans; Mesenchymal Stem Cells; Mice; Mice, Inbred C57BL; Osteoporosis, Postmenopausal; Recombinant Proteins; Transforming Growth Factor beta; Transforming Growth Factor beta1

To observe the effect of Modified Zuoguiwan (MZ) on the balance between helper T cell subsets 17 (Th17) and regulatory T cell subsets (Treg) in estrogen deficiency induced bone loss mice and to explore its mechanism.. Totally 50 BALB/c mice were divided into the sham-operation group, the ovariectomy model group, the low dose MZ group, the middle dose MZ group, and the high dose MZ group by random digit table, 10 in each group. Mice in the low, middle, and high dose MZ groups were respectively administered with MZ at the daily dose of 7.25, 14.50, and 29.00 g/kg by gastrogavage, 0.5 mL each time for 12 successive weeks. Meanwhile, mice in the sham-operation group and the ovariectomy model group were administered with equal volume by gastrogavage, 0.50 mL each time. The serum estradiol (E2) level was assessed by enzyme linked immunosorbent assay (ELISA). Bone mineral density (BMD) of thigh bone was measured with dual energy X ray absorptiometry. In addition, the population of Th17/Treg subsets in spleen mononuclear cells was analyzed by extracellular and intracellular staining method using flow cytometry. Moreover, the mRNA expression of IL-17A and TGF-β in the spleen mononuclear cells was detected by reverse transcription polymerase chain reaction (RT-PCR).. Compared with the sham-operation group, both E2 and BMD significantly decreased, the percentage of Th17 subset and Th17/Treg ratio both increased, the percentage of Treg subset obviously decreased, the expression of IL-17A mRNA significantly increased, and the expression of TGF-β mRNA significantly decreased in the ovariectomy model group (all P < 0.05). Compared with the model group, BMD obviously increased, the percentage of Th17 subset and Th17/Treg ratio both decreased, the percentage of Treg subset obviously increased, the expression of IL-17A mRNA significantly decreased, and the expression of TGF-β mRNA significantly increased in the middle dose MZ group and the high dose MZ group (all P < 0. 05). Correlation analyses showed that BMD was positively related to both the serum E2 level and the percentage of Treg subset (P < 0.05), but negatively related to the percentage of Th17 subset (P < 0.05). In addition, the serum E2 level was positively related to the percentage of Treg subset, but obviously negatively related to that of Th17 subset (P < 0.05).. There was correlation between Th17/Treg imbalance and E2 deficient bone loss. MZ could decrease the proportion of Th17 subset, but elevate the proportion of Treg subset in E2 deficient bone loss mice. It could achieve therapeutic effect through adjusting the balance of Th17/Treg in E2 deficient bone loss mice.

Topics: Animals; Drugs, Chinese Herbal; Estrogens; Female; Flow Cytometry; Humans; Interleukin-17; Mice; Mice, Inbred BALB C; Osteoporosis, Postmenopausal; RNA, Messenger; Spleen; T-Lymphocyte Subsets; T-Lymphocytes, Helper-Inducer; T-Lymphocytes, Regulatory; Th17 Cells; Transforming Growth Factor beta

Osteoporosis is a multifactorial disease in which genetic determinants are modulated by hormonal, environmental and nutritional factors. The balance between bone resorption and bone formation seems to be regulated by a variety of growth factors and cytokines. An important clinical risk factor in the pathogenesis of osteoporosis is the presence of genetic polymorphisms in susceptibility genes. In this study, we investigated the association between osteoporosis and interleukin 10 (IL-10) -597 C > A and transforming growth factor β1 (TGF-β1) T869C (also named Leu10 > Pro) polymorphisms in Turkish postmenopausal women. Genomic DNA obtained from 255 individuals (152 osteoporotic and 103 healthy controls). The DNA sample was isolated from peripheral bloods by salting-out method and analyzed by the techniques of PCR-RFLP. Genotype and allele frequencies were calculated and data were analyzed using the χ(2) test. We found a statistically significant difference between the groups with respect to IL-10 genotype distribution (p = 0.001) and allele frequencies (p < 0.0002). However, we did not found any difference between the groups with regarding TGF-β1 genotype distribution and allele frequencies (p > 0.05). In the combined genotype analysis, IL-10/TGF-β1 CCCC combine genotype was also estimated risk factor for osteoporosis in Turkish postmenopausal women (p = 0.026). To our knowledge, this is the first report to examine IL-10 gene -597 C > A polymorphism and osteoporosis in Turkish population.

Topics: Aged; Female; Gene Frequency; Genetic Association Studies; Genetic Predisposition to Disease; Genotype; Humans; Interleukin-10; Middle Aged; Osteoporosis, Postmenopausal; Polymorphism, Genetic; Surveys and Questionnaires; Transforming Growth Factor beta; Turkey

Bone morphogenetic proteins (BMPs) enhance bone formation. Numerous animal studies have established that BMPs can augment spinal fusion. However, there is a lack of data on the effect of BMP-2 on spinal fusion in the osteoporotic spine.. To investigate whether recombinant human BMP-2 (rhBMP-2) enhances spine fusion in an ovariectomized rat model.. In vivo animal study.. Female Sprague-Dawley rats (n=60) were ovariectomized or sham operated and randomized into three groups: Sham (sham operated+fusion), ovariectomy (OVX) (OVX+fusion), and BMP (OVX+fusion+BMP-2). Six weeks after ovariectomy, unilateral lumbar spine fusion was performed using autologous iliac bone with/without rhBMP-2 delivered on a collagen matrix. For each group, gene expression and histology were evaluated at 3 and 6 weeks after fusion, and bone parameters were measured by microcomputed tomography at 3, 6, 9, and 12 weeks.. Real-time reverse-transcription polymerase chain reaction at 3 weeks showed markedly increased expression of osteoblast-related markers (namely alkaline phosphatase, osteocalcin, Runx2, Smad1, and Smad5) in the BMP group compared with the other groups (p=.0005, .0005, .003, .009 and .012, respectively). Although the Sham and OVX groups showed both sparse and compacted bones between transverse processes at 6 weeks, the BMP group had a significantly larger bone mass within the fusion bed at 3 weeks and later. All rats in the BMP group had bridging bone at 3 weeks; at 12 weeks, bridging bones in the Sham and OVX groups were about 50% and 25%, respectively, of that in the BMP group.. Recombinant human BMP-2 enhances spinal fusion in OVX rats and acts during early bone formation. Therapeutic BMP-2 may therefore improve the outcome of spinal fusion in the osteoporotic patient.

Topics: Animals; Bone Morphogenetic Protein 2; Disease Models, Animal; Female; Humans; Osteogenesis; Osteoporosis, Postmenopausal; Ovariectomy; Rats; Rats, Sprague-Dawley; Real-Time Polymerase Chain Reaction; Recombinant Proteins; Reverse Transcriptase Polymerase Chain Reaction; Spinal Fusion; Transforming Growth Factor beta

To identify genes that are differently expressed in osteoporotic and non-osteoporotic human bone and to describe the relationships between these genes using multivariate data analysis.. Seven bone tissue samples from postmenopausal osteoporotic patients and 10 bone tissue samples from postmenopausal non-osteoporotic women were examined in our study. Messenger RNA was prepared from each sample and reverse transcribed to cDNA. The expression differences of 87 selected genes were analyzed in a Taqman probe-based quantitative real-time RT-PCR system.. A Mann-Whitney U-test indicated significant differences in the expression of nine genes (p < or = 0.05). Seven of these nine genes-ALPL, COL1A1, MMP2, MMP13, MMP9, PDGFA, NFKB1-were significantly downregulated in the bone tissue of osteoporotic women, while CD36 and TWIST2 were significantly upregulated in osteoporotic patients. Principal components analysis was used to evaluate data structure and the relationship between osteoporotic and non-osteoporotic phenotypes based on the multiple mRNA expression profiles of 78 genes. Canonical variates analysis demonstrated further that osteoporotic and non-osteoporotic tissues can be distinguished by expression analysis of genes coding growth factors/non-collagen matrix molecules, and genes belonging to the canonical TGFB pathway.. Significant differences observed in gene expression profiles of osteoporotic and non-osteoporotic human bone tissues provide further insight into the pathogenesis of this disease. Characterization of the differences between osteoporotic and non-osteoporotic bones by expression profiling will contribute to the development of diagnostic tools in the future.

Topics: Aged; Aging; Bone and Bones; Down-Regulation; Female; Gene Expression Profiling; Gene Expression Regulation; Genetic Variation; Humans; Intercellular Signaling Peptides and Proteins; Middle Aged; Multivariate Analysis; Osteoporosis, Postmenopausal; Principal Component Analysis; Proteins; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Transforming Growth Factor beta; Up-Regulation

Posterolateral intertransverse process spinal fusion (PLF) was performed in ovariectomized female rats using recombinant human BMP-7 (OP-1) delivered on a composite carrier.. To investigate whether BMP-7 collagen on a composite carrier in a higher dose will enhance posterolateral spinal fusion in an estrogen deficiency rat model.. Osteoporosis is a systemic disease characterized by bone remodeling skewed in favor of excess bone resorption. This makes new bone formation and fixation of metallic implants difficult. Thus, treating osteoporotic patients who require posterior spinal fusion is challenging. Ovariectomized rats have been used as an osteoporotic model for posterolateral intertransverse process fusion. We have demonstrated in the past that endochondral bone formation in osteoporotic rats is delayed when compared with rats without osteoporosis. We have also shown that OP-1 Putty (BMP-7, collagen, and carboxy-methyl-cellulose) can overcome the effects of osteoporosis in a rat fracture model. However, it has not yet been demonstrated whether BMP-7 collagen composite carrier (Calstrux) can achieve a fusion in a process spinal fusion model in osteoporotic bone.. A total of 42 ovariectomized Sprague-Dawley female rats were randomly assigned to 4 control and 2 experimental groups: (1) no Calstrux, no BMP; (2) 400 mg Calstrux alone; (3) 30 microg lactose + 400 mg Calstrux; (4) 90 microg lactose + 400 mg Calstrux; (5) 30 microg rhBMP-7 + 400 mg Calstrux; and (6) 90 microg rhBMP-7 + 400 mg Calstrux. Spinal fusion was evaluated by manual motion testing, microradiographs, computed tomographic scans, DEXA scans, and histology.. Ovariectomized rats receiving Calstrux alone or either dose of lactose and Calstrux did not show spinal fusion. Ovariectomized rats receiving 90 microg BMP-7 + 400 mg Calstrux showed significantly higher fusion rates than these control animals. (P < 0.0001). The rats receiving 30 microg BMP-7 + 400 mg Calstrux exhibited only partial fusion.. BMP-7, delivered on a composite carrier, is able to overcome the detrimental effects of estrogen deficiency on posterolateral spinal fusion and generate a relatively robust fusion. The effect seems to be dose dependent.

Topics: Absorptiometry, Photon; Animals; Bone Morphogenetic Protein 7; Bone Morphogenetic Proteins; Collagen; Combined Modality Therapy; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Delivery Systems; Female; Humans; Movement; Osteoporosis, Postmenopausal; Ovariectomy; Rats; Rats, Sprague-Dawley; Spinal Fusion; Tomography, X-Ray Computed; Transforming Growth Factor beta

Osteoporosis is a major public health problem and the most obvious preventive strategy, hormone replacement therapy, has lost favor due to recent findings of the Women's Health Initiative regarding increased risks of breast cancer and cardiovascular disease. Resveratrol, a naturally occurring compound possessing estrogenic activity, is thought to have considerable potential for therapy of osteoporosis. In the present study, resveratrol was found to exhibit bone-protective effects equivalent to those exerted by hormone replacement therapy and decrease the risk of breast cancer in the in vivo and in vitro models. Forkhead proteins were found to be essential for both effects of resveratrol. The bone-protective effect was attributable to induction of bone morphogenetic protein-2 through Src kinase-dependent estrogen receptor activation and FOXA1 is required for resveratrol-induced estrogen receptor-dependent bone morphogenetic protein-2 expression. The tumor-suppressive effects of resveratrol were the consequence of Akt inactivation-mediated FOXO3a nuclear accumulation and activation. Resveratrol is therefore anticipated to be highly effective in management of postmenopausal osteoporosis without an increased risk of breast cancer.

Topics: Animals; Antineoplastic Agents, Phytogenic; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Breast Neoplasms; Cell Line, Tumor; Estrogen Replacement Therapy; Estrogens; Female; Forkhead Transcription Factors; Gene Expression Regulation, Enzymologic; Humans; Mice; Osteoporosis, Postmenopausal; Proto-Oncogene Proteins c-akt; Receptors, Estrogen; Resveratrol; Risk Factors; src-Family Kinases; Stilbenes; Transforming Growth Factor beta

The aim of this study was to examine whether the 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 (COL1A-1; 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 control group of postmenopausal females in the same age range (mean age 59.1 years) with normal BMD.. We have not found any statistically significant differences in the frequency of the individual genotypes or alleles of analyzed variants between the groups of osteoporotic patients (OP), population group (PG) and control group (CG). The frequencies of the individual genotypes in the analyzed groups were 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 64.9%, "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 COL1A-1 (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; Czech Republic; Female; Genetic Predisposition to Disease; Humans; Middle Aged; Osteoporosis, Postmenopausal; Plasminogen Activator Inhibitor 1; Polymorphism, Genetic; Reference Values; Transforming Growth Factor beta; White People

Genetic contributions play an important role in determining bone mineral density (BMD) and bone turnover. Transforming growth factor-beta (TGF-beta) is abundant in bone and has been implicated as an important regulator of both bone formation and resorption. Several polymorphisms of the TGF-beta1 gene have recently been suggested to be associated with BMD and susceptibility to osteoporotic spine fractures. To determine the relationship between TGF-beta1 polymorphisms and BMD in southern Chinese women, three SNPs at C(-1348) -T, T29 -C, and T(861-20) -C of TGF-beta1 gene were analyzed in 237 postmenopausal southern Chinese women by RFLP and direct sequencing. BMD at the lumbar spine and hip region, biochemical markers of bone turnover, as well as serum levels of TGF-beta1 were measured. Only the T29 -C polymorphism of TGF-beta1 gene was associated with BMD and fracture risk. The prevalence of fragility fractures was significantly higher in individuals with TC genotype (P < 0.05). Serum alkaline phosphatase and osteocalcin levels as well as urinary N-telopeptide excretion were significantly higher in women with TC than with TT or CC genotypes, and the difference remained significant after adjusting for age and BMI (all P < 0.05). Women with TC genotype had lower BMD at the trochanteric (P < 0.03) and total hip region (P = 0.05). No difference was observed in the serum TGF-beta1 levels among the three genotypes. In conclusion, an association between T29 -C polymorphisms of TGF-beta1 gene and BMD, bone turnover as well as fragility fractures were demonstrated in postmenopausal southern Chinese women.

Topics: Aged; Asian People; Biomarkers; Bone and Bones; Bone Density; Bone Remodeling; Female; Fractures, Bone; Hong Kong; Humans; Osteoporosis, Postmenopausal; Polymerase Chain Reaction; Polymorphism, Genetic; Polymorphism, Restriction Fragment Length; Risk; Transforming Growth Factor beta; Transforming Growth Factor beta1

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

The objective of this study was to evaluate the role of osteoclast activating cytokines, interleukin-11 (IL-11) and transforming growth factor-beta2 (TGF-beta2) in the assessment of bone turnover in postmenopausal osteoporosis (PO). Eighty postmenopausal osteoporotic women with lumbar spine bone mineral densities (BMD) as measured by DEXA that were more than 2.5 SD below the normal mean of healthy women (controls), participated in this study. Various therapeutic modalities (hormone replacement therapy, HRT, alendronate, calcitonin and 1alpha-hydroxyvitamin D (alfacalcidol) were administered for 12 months to 4 groups of postmenopausal osteoporotic patients. Fasting blood samples and two hour urine samples were collected from control subjects and from patients before and after treatment. Serum samples were assayed for IL-11, TGF-beta2, osteocalcin (OC) and bone alkaline phosphatase (B-ALP), whereas urine samples were assayed for N-telopeptide for type I collagen (NTX) and deoxypyridinoline (DPyr). The results demonstrated a significant increase of both IL-11 and TGF-beta2 in postmenopausal osteoporosis. Positive correlations exist between TGF-beta2 or IL-11 and markers of bone resorption (NTX and DPyr). Moreover, there was a significant positive correlation between TGF-beta2 and IL-11. Therapeutic modalities enhancing bone formation and/or with antiresorptive effect revealed a significant decrease in markers of bone resorption, formation and osteoclast activating cytokines, indicating a decrease in bone turnover. The decrease of IL-11 and TGF-beta2 may be attributed to a drug inhibitory effect of these cytokines on enhancing osteoblast mediated osteoid degradation. In conclusion, both serum IL-11 and TGF-beta2 determinations may be considered as biomarkers for the assessment of bone turnover and for monitoring antiresorptive therapy in postmenopausal osteoporosis.

Topics: Adult; Amino Acids; Biomarkers; Bone Density; Bone Resorption; Collagen; Collagen Type I; Female; Humans; Interleukin-11; Middle Aged; Osteoporosis, Postmenopausal; Peptides; Transforming Growth Factor beta; Transforming Growth Factor beta2

TGF-beta1 is thought to play an important role in bone turnover. Thus, the gene encoding TGF-beta1 is a prime candidate for the genetic regulation of bone density. Recent studies have suggested that a T29 --> C polymorphism in the signal sequence region of the TGF-beta1 gene may be related to bone mineral density (BMD) and bone loss in postmenopausal Japanese women. In the present study, we examined the relationship between this polymorphism and BMD in a population-based sample of 102 estrogen-deficient postmenopausal women from the Heidelberg cohort of the European Vertebral Osteoporosis Study (EVOS). Average BMD in women with the TT genotype was approximately 10% higher at both the lumbar spine and the femoral neck compared with women with the CC genotype (spine: 980 vs. 887 mg/cm2, P = 0.05; femoral neck: 755 vs. 674 mg/cm2; P = 0.02). Women with the TT genotype also experienced less overall bone loss at the total hip, compared with women with the CC genotype. Serum levels of TGF-beta1 were higher in women with the TT genotype than in those with the CC genotype (46.5 ng/ml vs. 32.3 ng/ml, P = 0.001). These data are clearly in contrast to findings in postmenopausal Japanese women where the CC genotype was associated with higher BMD and decreased bone loss. Further studies are therefore necessary to clarify the relationship between this polymorphism and BMD.

Topics: Aged; Bone Density; Cohort Studies; DNA; Female; Femur Neck; Genetic Predisposition to Disease; Genotype; Germany; Humans; Lumbar Vertebrae; Middle Aged; Molecular Epidemiology; Osteoporosis, Postmenopausal; Polymerase Chain Reaction; Polymorphism, Genetic; Postmenopause; Transforming Growth Factor beta; Transforming Growth Factor beta1

Transforming growth factor beta (TGF-beta) is an important regulator of bone metabolism, its effects being intertwined with those of estrogen and vitamin D. A T-->C polymorphism in exon 1 of the TGF-beta1 gene, which results in the substitution of proline for leucine, is associated with bone mineral density (BMD). However, it is not known whether this polymorphism affects the response to treatment with active vitamin D or to hormone replacement therapy (HRT) in individuals with osteoporosis. Changes in BMD at the lumbar spine (L2-L4 BMD) were compared among TGF-beta1 genotypes in 363 postmenopausal Japanese women who were divided into three groups: an untreated, control group (n = 130), an active vitamin D treatment group (n = 117), and an HRT group (n = 116). TGF-beta1 genotype was determined with an allele-specific polymerase chain reaction assay. In the control group, the rate of bone loss decreased according to the rank order of genotypes TT (homozygous for the T allele) > TC (heterozygous) > CC (homozygous for the C allele), with a significant difference detected between the CC and TT genotypes. The positive response of L2-L4 BMD to HRT increased according to the rank order of genotypes TT < TC < CC, although the differences among genotypes were not statistically significant. Individuals with the CC genotype responded to active vitamin D treatment with an annual increase in L2-L4 BMD of 1.6%, whereas those with the TT or TC genotypes similarly treated lost bone to a similar extent as did untreated subjects of the corresponding genotype. These results suggest that TGF-beta1 genotype is associated with both the rate of bone loss and the response to active vitamin D treatment.

Topics: Aged; Amino Acid Substitution; Bone Density; Bone Resorption; Calcitriol; Estrogen Replacement Therapy; Estrogens, Conjugated (USP); Exons; Female; Gene Frequency; Genotype; Humans; Hydroxycholecalciferols; Japan; Medroxyprogesterone Acetate; Middle Aged; Osteoblasts; Osteoporosis, Postmenopausal; Ovariectomy; Point Mutation; Protein Sorting Signals; Transforming Growth Factor beta; Treatment Outcome

Transforming growth factor beta1 (TGF-beta1) is abundant in bone and is an important regulator of the osteoclastic-osteoblastic interaction (coupling). The sequence variation, 713-8delC in the TGF-beta1 gene has previously been found to be associated with very low bone mass in osteoporotic women and with increased bone turnover in both osteoporotic and normal women. The possible association of this polymorphism with bone mass and bone turnover has now been investigated in 256 postmenopausal Italian women. A significant association of TGF-beta1 with bone mass was detected in the populations. Subjects carrying the sequence variation 713-8delC (Tt) genotype showed a significantly lower bone mineral density (BMD) at the hip than those without sequence variation in the genotype (TT). Individuals carrying the tt genotype have a more severe osteoporosis (P=0.0001 vs. TT and Tt genotypes). The frequency of the fragility fractures was significantly lower in individuals with TT genotype than in those with the Tt and tt genotypes (X2=21.9; P=0.006). Furthermore a significant association was found between 713-8delC and bone turnover. The results suggest a strong evidence for an association among the 713-8delC allele of the TGF-beta1 gene and the femoral BMD, the prevalence of osteoporotic fractures, and finally a high bone turnover in a sample of Italian postmenopausal women.

Topics: Aged; Bone Density; Female; Humans; Italy; Middle Aged; Osteoporosis, Postmenopausal; Polymorphism, Genetic; Postmenopause; Transforming Growth Factor beta

Mesenchymal stem cells (MSCs), precursor cells resident in the bone marrow, have the capacity to differentiate into bone, cartilage, fat, and connective tissue. We have recently reported that MSCs from "healthy" donors differ from cells obtained from osteoporotic postmenopausal women in their proliferation rate, mitogenic response to osteogenic growth factors, and potential to mineralize. The purpose of this study was to examine the factors that explain the differential capacity of MSCs derived from "healthy" control and osteoporotic postmenopausal women to support mineralization. In addition, we examined the factors that regulate the differentiation of osteoporotic cells into adipocytes. For this purpose, we isolated MSCs from bone marrow of donors and analyzed the synthesis and deposition of type I collagen, the main component of bone extracellular matrix, the time course of gelatinolytic activity expression, the deposition of transforming growth factor beta (TGF-beta), and the ability of cells to differentiate into adipocytes. Our results indicate that cells derived from osteoporotic donors synthesized 50% less type I collagen than normal cells and maintained higher levels of gelatinolytic activity under differentiation conditions (70% versus 15% after 14 days in culture). MSCs derived from osteoporotic women produced 60-65% less TGF-beta and expressed higher adipogenic capacity. We conclude that the capacity of MSCs derived from osteoporotic postmenopausal women to generate and maintain type I collagen-rich extracellular matrix is decreased, favoring their adipogenic differentiation. These observations may explain the decreased mineralization previously observed in these types of cells.

Topics: Adipocytes; Aged; Case-Control Studies; Cell Differentiation; Collagen; Extracellular Matrix; Female; Gelatinases; Hematopoietic Stem Cells; Humans; In Vitro Techniques; Osteoporosis, Postmenopausal; Transforming Growth Factor beta

Osteoporosis is a major public health problem characterized by low bone mineral density (BMD) that presently has no biochemical test useful for its diagnosis. The cytokine TGF-beta has been postulated to play a role in controlling bone density by regulating the fine balance between bone matrix deposition by osteoblasts and its resorption by osteoclasts. We explored whether measurement of serum levels of different TGF-beta isoforms could be useful as a clinical tool in osteoporosis. We measured the concentration of TGF-beta1 antigen using the BDA19 capture sandwich enzyme-linked immunosorbent assay (ELISA), TGF-beta2 antigen concentration using a Quantikine sandwich ELISA kit and TGF-beta3 antigen concentration using a modified version of the TGF-beta1 Quantikine sandwich ELISA kit. Subjects were 41 women with osteoporosis (with nontraumatic vertebral fracture or lumbar spine BMD Z-score <-1.5 SD) and a total of 199 control women from different sources. Serum concentrations of TGF-beta1 and TGF-beta2 were similar in all groups. However, detectable levels of TGF-beta3 (>0.2 ng/ml) were found in 35 of 41 patients with osteoporosis (median 7.2 (5.2-8.9) ng/ml) compared with 11 of 36 controls or 24 of 89 healthy women of unknown bone density. Differences among the groups could not be accounted for by age, weight, medications, use of hormone replacement therapy or the presence of osteoarthritis. Using the optimal cut-off of >/=2 ng/ml, the test was able to detect an individual with low spine BMD (Z-score <-1.5) with a sensitivity of 84% and a specificity of 53%, with similar results for the femoral neck. The odds ratio for osteoporosis associated with a positive test at this level was 5.93 (95% CI 2.41-11.59), and 4.1 (95% CI 1.66-10.11) using the WHO cut-off of T-score <-2.5. Serum TGF-beta3 concentration is raised in osteoporotic women and the test appears to have potential as a marker for osteoporosis. The underlying mechanisms and the relationships between TGF-beta3 and bone turnover and fractures remain to be explored.

Topics: Analysis of Variance; Biomarkers; Bone Density; Case-Control Studies; Enzyme-Linked Immunosorbent Assay; Female; Humans; Middle Aged; Odds Ratio; Osteoporosis, Postmenopausal; Protein Isoforms; ROC Curve; Sensitivity and Specificity; Transforming Growth Factor beta

Topics: Animals; Bone Resorption; Estradiol; Estrogen Antagonists; Estrogens; Female; Gene Expression Regulation; Humans; Mice; Osteoblasts; Osteoclasts; Osteoporosis, Postmenopausal; Piperidines; Raloxifene Hydrochloride; Tamoxifen; Transforming Growth Factor beta

Postmenopausal osteoporosis, the most common bone disease in the developed world, is associated with estrogen deficiency. This deficiency induces increased generation and activity of osteoclasts, which perforate bone trabeculae, thus reducing their strength and increasing fracture risk. Estrogen replacement prevents these effects, indicating that estrogen negatively regulates osteoclast formation and function, but how it does this is unclear. Because functional osteoclast life span and thus the amount of bone that osteoclasts resorb could also be enhanced following estrogen deficiency, and since sex steroids regulate apoptosis in other target tissues, we investigated whether estrogen may affect osteoclast function by promoting apoptosis. 17 beta-Estradiol promoted apoptosis of murine osteoclasts in vitro and in vivo by two- to threefold. Tamoxifen, which has estrogenic effects on bone resorption, and transforming growth factor-beta 1 (TGF-beta), whose production by osteoblasts is increased by estrogen, had similar effects in vitro. Anti-TGF-beta antibody inhibited TGF-beta-, estrogen- and tamoxifen-induced osteoclast apoptosis, indicating that TGF-beta might mediate this effect. These findings suggest that estrogen may prevent excessive bone loss before and after the menopause by limiting osteoclast life span through promotion of apoptosis. The development of analogues to promote this mechanism specifically could be a useful and novel therapeutic approach to prevent postmenopausal osteoporosis.

Topics: Animals; Apoptosis; Bone and Bones; Bone Resorption; Cell Count; Cells, Cultured; Estradiol; Estrogen Antagonists; Female; Gene Expression Regulation; Humans; Mice; Mice, Inbred C57BL; Organ Size; Osteoblasts; Osteoclasts; Osteoporosis, Postmenopausal; Ovariectomy; Tamoxifen; Transforming Growth Factor beta; Uterus

Estrogen deficiency in rats is responsible for increased osteoclastic resorption and a subsequent rapid bone loss. TGF-beta, which is known to have acute effects on bone resorption in several in vitro models, has been shown to be secreted by osteoblastic cells in vitro in response to 17 beta-estradiol, but little is known about its in vivo effects on bone resorption. We therefore decided to investigate the short-term effect of TGF-beta 1 on bone resorption in ovariectomized rats. TGF-beta 1 (0.04-20 ng/injection), or vehicle, was injected daily directly into the bone marrow space, through a thin catheter implanted in the distal end of the right femur, during 4 consecutive days, starting 14 days after the ovariectomy. Bone histomorphometry was performed in the secondary spongiosa of the metaphysis of injected femurs and compared with vehicle-injected femurs of sham ovariectomized rats. Ovariectomy was associated with a marked increase in the resorption surface, a 2-fold increase in the number of osteoclasts, and no change in the number of TRAP-positive marrow cells distant from bone surfaces. Bone resorption was significantly lower in the TGF-beta 1-injected bones of ovariectomized rats, as compared with vehicle injected bones: the osteoclast surface and the number of osteoclasts were, respectively, 11.0 +/- 5.1% versus 20.8 +/- 1.3% and 287 +/- 41 versus 505 +/- 53, in bones injected with 0.2 ng of TGF-beta 1 as compared with vehicle-injected bones (mean +/- SE, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Analysis of Variance; Animals; Bone Development; Bone Marrow; Bone Resorption; Catheterization; Disease Models, Animal; Dose-Response Relationship, Drug; Estrogens; Female; Femur; Humans; Osteoclasts; Osteoporosis, Postmenopausal; Ovariectomy; Rats; Rats, Sprague-Dawley; Tetracycline; Transforming Growth Factor beta

In vitro studies indicate that transforming growth factor-beta (TGF-beta) has a role in the regulation of bone cell activities. However, little is known about the effects of TGF-beta on bone when it is administered systemically. This study was undertaken to evaluate the in vivo effects of TGF-beta 2 on bone and marrow cells in the ovariectomized rat bone loss model. Female Sprague-Dawley rats, aged 95 days, were divided into 4 groups. Group 1 was sham operated; groups 2-4 were ovariectomized. Groups 3 and 4 received daily injections of 10 micrograms and 50 micrograms of TGF-beta 2/kg body weight, respectively. Groups 1 and 2 received the solvent vehicle. All animals were sacrificed after 35 days. Ovariectomy caused a significant increase in, total mononuclear marrow cells, the number of TRAP positive multinucleated cells formed in culture of marrow cells, and the number of trabecular osteoclasts and osteoblasts. These increases were associated with loss of cancellous bone in the proximal tibia. TGF-beta 2 completely prevented the increase in the number of TRAP positive multinucleated cells, and caused a small but not statistically significant decrease in the number of trabecular osteoclasts. However, TGF-beta 2 had no significant effect on the number of total mononuclear marrow cells and on the loss of cancellous bone due to ovariectomy. We conclude that TGF-beta 2 probably plays a role in the regulation of the proliferation of osteoclast progenitors in bone marrow in vivo. Studies carried out over a longer period are required to determine whether it will modulate the increase in osteoclast and osteoblast numbers that occur in cancellous bone following ovariectomy.

Topics: Animals; Bone Density; Bone Marrow; Bone Marrow Cells; Cell Count; Disease Models, Animal; Female; Giant Cells; Humans; Osteoblasts; Osteoclasts; Osteoporosis, Postmenopausal; Ovariectomy; Rats; Rats, Sprague-Dawley; Transforming Growth Factor beta

Previous work showed that production of transforming growth factor beta (TGF-beta) by osteoblast-like rat UMR 106 cells was increased by 17 beta-estradiol at physiological concentrations. To determine whether ovariectomy alters the concentration of TGF-beta in rat long bones, female Sprague-Dawley rats were either sham-operated (n = 19) or ovariectomized (n = 19), pair-fed a semisynthetic diet for 6 weeks, and sacrificed. Tibial and femoral diaphyses were removed and extracted by demineralization. Ovariectomy lowered serum estrogen; did not alter body weight, serum magnesium, or serum 1,25-dihydroxyvitamin D; and produced only modest differences in serum calcium and phosphate concentrations. Hydroxyproline was higher and extractable protein was lower in bones from ovariectomized rats than in bones from sham-operated rats; calcium content did not differ between the two groups of animals. Ovariectomy lowered the concentration of TGF-beta in bone but did not change the concentration of insulin-like growth factors I or II compared with values in bone from control animals. The reduction of bone TGF-beta was evident 6 weeks after surgery but not at 3 weeks. Treatment of ovariectomized rats with estrogen eliminated the TGF-beta deficit. To determine whether 17 beta-estradiol increased TGF-beta production by normal bone cells, mouse osteoblasts were treated for 2 days with 17 beta-estradiol. The production of TGF-beta was increased almost 2-fold by 1 nM 17 beta-estradiol, and short-term treatment stimulated the intracellular accumulation of TGF-beta 1 mRNA. We conclude that ovariectomy reduces deposition of TGF-beta in rat bone and that diminished skeletal TGF-beta could play a role in the pathogenesis of bone loss, fractures, and microfractures that occur in estrogen-deficient states. Our results support the possibility that estrogen and bone TGF-beta may be necessary for normal maintenance of the skeleton in female rats.

Topics: Animals; Body Weight; Bone and Bones; Cells, Cultured; Estradiol; Female; Gene Expression; Humans; In Vitro Techniques; Insulin-Like Growth Factor I; Insulin-Like Growth Factor II; Mice; Osteoporosis, Postmenopausal; Ovariectomy; Rats; Rats, Sprague-Dawley; RNA, Messenger; Transforming Growth Factor beta