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Abstract
Traditional textbook physiology has ascribed unitary functions to hormones from the anterior and posterior pituitary gland, mainly in the regulation of effector hormone secretion from endocrine organs. However, the evolutionary biology of pituitary hormones and their receptors provides evidence for a broad range of functions in vertebrate physiology. Over the past decade, we and others have discovered that thyroid-stimulating hormone, follicle-stimulating hormone, adrenocorticotropic hormone, prolactin, oxytocin and arginine vasopressin act directly on somatic organs, including bone, adipose tissue and liver. New evidence also indicates that pituitary hormone receptors are expressed in brain regions, nuclei and subnuclei. These studies have prompted us to attribute the pathophysiology of certain human diseases, including osteoporosis, obesity and neurodegeneration, at least in part, to changes in pituitary hormone levels. This new information has identified actionable therapeutic targets for drug discovery.
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Affiliation(s)
- Mone Zaidi
- Center for Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
- Departments of Medicine and Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Tony Yuen
- Center for Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Departments of Medicine and Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Se-Min Kim
- Center for Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Departments of Medicine and Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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Liu Z, Tong H, Su B, Yu M, Chen Y. The non-linear associations of serum follicle-stimulating hormone levels with bone mineral density and the risk of osteoporosis during menopausal transition: an analysis of National Health and Nutrition Examination Survey data. Endocrine 2023; 80:212-220. [PMID: 36477941 DOI: 10.1007/s12020-022-03278-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 11/28/2022] [Indexed: 12/12/2022]
Abstract
PURPOSE To explore the non-linear associations of serum FSH levels with BMD and the risk of osteoporosis in pre- and postmenopausal women. METHODS Data analyzed in this study were derived from the National Health and Nutrition Examination Survey (NHANES) III and the NHANES from 1999 to 2002. Women aged from 35 to 60 years with complete data of serum FSH levels and BMD were eligible. Serum FSH levels were assayed using the Microparticle Enzyme Immunoassay technology. Lumbar spine and femur neck BMD were measured using a dual energy X-ray absorptiometry. Osteoporosis was assessed according to BMD of lumbar spine, total femur, and femur neck. RESULTS This study included 3743 women. A significant non-linear association of serum FSH levels with lumbar spine BMD was observed only in postmenopausal women (P for non-linear association = 0.013) but not in premenopausal women (P for non-linear association = 0.092). The results of femur neck BMD were comparable with those of lumbar spine BMD. Meanwhile, there was significant non-linear association of serum FSH levels with the risk of osteoporosis only in postmenopausal women (P for non-linear association = 0.050). CONCLUSION Non-linear associations of serum FSH levels with BMD at lumbar spine and femur neck were observed only in postmenopausal women. Meanwhile, serum FSH levels were non-linearly associated with the risk of osteoporosis in postmenopausal women.
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Affiliation(s)
- Zhize Liu
- Department of Orthopaedics, Affiliated Dalian Municipal Central Hospital of Dalian Medical University, Dalian, 116021, China
| | - Huixin Tong
- Department of Endocrinology, General Hospital of Northern Theater Command, Shenyang, 110016, China
| | - Bo Su
- Department of Orthopedics, The Second Affiliated Hospital of Harbin Medical University, Harbin, 150081, China
| | - Meixue Yu
- Health Management Center, Affiliated Dalian Municipal Central Hospital of Dalian Medical University, Dalian, 116021, China
| | - Yongjie Chen
- Department of Epidemiology and Statistics, School of Public Health, Tianjin Medical University, Tianjin, 300070, China.
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Kim SM, Sultana F, Korkmaz F, Lizneva D, Yuen T, Zaidi M. Independent Skeletal Actions of Pituitary Hormones. Endocrinol Metab (Seoul) 2022; 37:719-731. [PMID: 36168775 PMCID: PMC9633224 DOI: 10.3803/enm.2022.1573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 09/02/2022] [Indexed: 12/30/2022] Open
Abstract
Over the past years, pituitary hormones and their receptors have been shown to have non-traditional actions that allow them to bypass the hypothalamus-pituitary-effector glands axis. Bone cells-osteoblasts and osteoclasts-express receptors for growth hormone, follicle stimulating hormone (FSH), thyroid stimulating hormone (TSH), adrenocorticotrophic hormone (ACTH), prolactin, oxytocin, and vasopressin. Independent skeletal actions of pituitary hormones on bone have been studied using genetically modified mice with haploinsufficiency and by activating or inactivating the receptors pharmacologically, without altering systemic effector hormone levels. On another front, the discovery of a TSH variant (TSH-βv) in immune cells in the bone marrow and skeletal action of FSHβ through tumor necrosis factor α provides new insights underscoring the integrated physiology of bone-immune-endocrine axis. Here we discuss the interaction of each pituitary hormone with bone and the potential it holds in understanding bone physiology and as a therapeutic target.
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Affiliation(s)
- Se-Min Kim
- The Mount Sinai Bone Program, Departments of Pharmacological Sciences and Medicine, and Center of Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Corresponding authors: Se-Min Kim. The Mount Sinai Bone Program, Departments of Pharmacological Sciences and Medicine, and Center of Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, PO Box 1055, New York, NY 10029, USA Tel: +1-212-241-8797, Fax: +1-212-426-8312 E-mail:
| | - Farhath Sultana
- The Mount Sinai Bone Program, Departments of Pharmacological Sciences and Medicine, and Center of Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Funda Korkmaz
- The Mount Sinai Bone Program, Departments of Pharmacological Sciences and Medicine, and Center of Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Daria Lizneva
- The Mount Sinai Bone Program, Departments of Pharmacological Sciences and Medicine, and Center of Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Tony Yuen
- The Mount Sinai Bone Program, Departments of Pharmacological Sciences and Medicine, and Center of Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Mone Zaidi
- The Mount Sinai Bone Program, Departments of Pharmacological Sciences and Medicine, and Center of Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Mone Zaidi. The Mount Sinai Bone Program, Departments of Pharmacological Sciences and Medicine, and Center of Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, PO Box 1055, New York, NY 10029, USA Tel: +1-212-241-8797, Fax: +1-212-426-8312, E-mail:
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Mills EG, Yang L, Nielsen MF, Kassem M, Dhillo WS, Comninos AN. The Relationship Between Bone and Reproductive Hormones Beyond Estrogens and Androgens. Endocr Rev 2021; 42:691-719. [PMID: 33901271 PMCID: PMC8599211 DOI: 10.1210/endrev/bnab015] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Indexed: 12/20/2022]
Abstract
Reproductive hormones play a crucial role in the growth and maintenance of the mammalian skeleton. Indeed, the biological significance for this hormonal regulation of skeletal homeostasis is best illustrated by common clinical reproductive disorders, such as primary ovarian insufficiency, hypothalamic amenorrhea, congenital hypogonadotropic hypogonadism, and early menopause, which contribute to the clinical burden of low bone mineral density and increased risk for fragility fracture. Emerging evidence relating to traditional reproductive hormones and the recent discovery of newer reproductive neuropeptides and hormones has deepened our understanding of the interaction between bone and the reproductive system. In this review, we provide a contemporary summary of the literature examining the relationship between bone biology and reproductive signals that extend beyond estrogens and androgens, and include kisspeptin, gonadotropin-releasing hormone, follicle-stimulating hormone, luteinizing hormone, prolactin, progesterone, inhibin, activin, and relaxin. A comprehensive and up-to-date review of the recent basic and clinical research advances is essential given the prevalence of clinical reproductive disorders, the emerging roles of upstream reproductive hormones in bone physiology, as well as the urgent need to develop novel safe and effective therapies for bone fragility in a rapidly aging population.
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Affiliation(s)
- Edouard G Mills
- Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | - Lisa Yang
- Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | - Morten F Nielsen
- Department of Endocrinology, University Hospital of Odense & institute of Clinical Research, University of Southern Denmark, 5000 Odense C, Denmark
| | - Moustapha Kassem
- Department of Endocrinology, University Hospital of Odense & institute of Clinical Research, University of Southern Denmark, 5000 Odense C, Denmark.,Faculty of Health and Medical Sciences, Department of Cellular and Molecular Medicine, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Waljit S Dhillo
- Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK.,Department of Endocrinology, Imperial College Healthcare NHS Trust, London, UK
| | - Alexander N Comninos
- Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK.,Department of Endocrinology, Imperial College Healthcare NHS Trust, London, UK.,Endocrine Bone Unit, Imperial College Healthcare NHS Trust, London, UK
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5
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Wu KC, Ewing SK, Li X, Sigurðsson S, Guðnason V, Kado DM, Hue TF, Woods GN, Veldhuis-Vlug AG, Vittinghoff E, Zaidi M, Rosen CJ, Lang T, Kim TY, Schwartz AV, Schafer AL. FSH Level and Changes in Bone Mass and Body Composition in Older Women and Men. J Clin Endocrinol Metab 2021; 106:2876-2889. [PMID: 34212197 PMCID: PMC8475206 DOI: 10.1210/clinem/dgab481] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Indexed: 01/02/2023]
Abstract
CONTEXT FSH may have independent actions on bone remodeling and body fat regulation. Cross-sectionally, we have shown that serum FSH is associated with bone mineral density (BMD) and body fat in older postmenopausal women, but it remains unknown whether FSH predicts bone and fat changes. OBJECTIVE We examined whether baseline FSH level is associated with subsequent bone loss or body composition changes in older adults. SETTING, DESIGN, PARTICIPANTS We studied 162 women and 158 men (mean age 82 ± 4 years) from the Age, Gene/Environment Susceptibility (AGES)-Bone Marrow Adiposity cohort, a substudy of the AGES-Reykjavik Study of community-dwelling older adults. Skeletal health and body composition were characterized at baseline and 3 years later. MAIN OUTCOMES Annualized change in BMD and body composition by dual-energy X-ray absorptiometry (DXA) and quantitative computed tomography (QCT). Models were adjusted for serum estradiol and testosterone levels. RESULTS There was no evidence for an association between baseline FSH level and change in BMD or body composition by DXA or QCT. For femoral neck areal BMD, adjusted mean difference (95% CI) per SD increase in FSH was 1.3 (-0.7 to 3.3) mg/cm2/y in women, and -0.2 (-2.6 to 2.2) mg/cm2/y in men. For visceral fat, adjusted mean difference (95% CI) per SD increase in FSH was 1.80 (-0.03 to 3.62) cm2/y in women, and -0.33 (-3.73 to 3.06) cm2/y in men. CONCLUSIONS Although cross-sectional studies and studies in perimenopausal women have demonstrated associations between FSH and BMD and body composition, in older adults, FSH level is not associated with bone mass or body composition changes.
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Affiliation(s)
- Karin C Wu
- Department of Medicine, University of California San Francisco, San Francisco, CA 94143, USA
- Endocrine Research Unit, San Francisco Veterans Affairs Health Care System, San Francisco, CA 94121, USA
- Correspondence: Karin C. Wu, MD, 1700 Owens St., RM 349, San Francisco, CA 94158, USA.
| | - Susan K Ewing
- Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA 94143, USA
| | - Xiaojuan Li
- Program of Advanced Musculoskeletal Imaging, Cleveland Clinic, Cleveland, OH 44195, USA
| | | | - Vilmundur Guðnason
- Icelandic Heart Association Research Institute, 201 Kópavogur, Iceland
- Faculty of Medicine, University of Iceland, Reykjavik, Iceland
| | - Deborah M Kado
- Department of Medicine, Stanford University, Stanford, CA 94305, USA
- Geriatric Research Education and Clinical Center, Veterans Affairs Health Care System, Palo Alto, CA 94304, USA
| | - Trisha F Hue
- Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA 94143, USA
| | - Gina N Woods
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
- Veterans Affairs San Diego Healthcare System, San Diego, CA 92161, USA
| | - Annegreet G Veldhuis-Vlug
- Center for Clinical and Translational Research, Maine Medical Center Research Institute, Scarborough, ME 04074, USA
- Center for Bone Quality, Department of Endocrinology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
| | - Eric Vittinghoff
- Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA 94143, USA
| | - Mone Zaidi
- The Mount Sinai Bone Program and Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Clifford J Rosen
- Center for Clinical and Translational Research, Maine Medical Center Research Institute, Scarborough, ME 04074, USA
| | - Thomas Lang
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA 94143, USA
| | - Tiffany Y Kim
- Department of Medicine, University of California San Francisco, San Francisco, CA 94143, USA
- Endocrine Research Unit, San Francisco Veterans Affairs Health Care System, San Francisco, CA 94121, USA
| | - Ann V Schwartz
- Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA 94143, USA
| | - Anne L Schafer
- Department of Medicine, University of California San Francisco, San Francisco, CA 94143, USA
- Endocrine Research Unit, San Francisco Veterans Affairs Health Care System, San Francisco, CA 94121, USA
- Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA 94143, USA
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Tantikanlayaporn D, Wichit P, Suksen K, Suksamrarn A, Piyachaturawat P. Andrographolide modulates OPG/RANKL axis to promote osteoblastic differentiation in MC3T3-E1 cells and protects bone loss during estrogen deficiency in rats. Biomed Pharmacother 2020; 131:110763. [DOI: 10.1016/j.biopha.2020.110763] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 09/13/2020] [Accepted: 09/16/2020] [Indexed: 11/26/2022] Open
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Khosla S. Estrogen Versus FSH Effects on Bone Metabolism: Evidence From Interventional Human Studies. Endocrinology 2020; 161:5865207. [PMID: 32602895 PMCID: PMC7371389 DOI: 10.1210/endocr/bqaa111] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 06/26/2020] [Indexed: 12/13/2022]
Abstract
Provocative mouse studies and observational human data have generated considerable enthusiasm for modulating follicle-stimulating hormone (FSH) action in humans to prevent bone loss and, in addition, to treat obesity. This perspective summarizes the strengths and potential weaknesses of the mouse studies examining the skeletal phenotype of FSHβ or FSH receptor null mice, as well as more recent studies using FSH neutralizing antibodies. Although human observational studies do demonstrate correlation of serum FSH levels with postmenopausal bone loss, these studies cannot distinguish whether serum FSH is simply a better biomarker than estradiol or causally related to the bone loss. Establishing causality requires direct interventional studies either suppressing or infusing FSH in humans and to date, such studies have uniformly failed to demonstrate an effect of FSH on bone turnover independent of changes in sex steroid levels. In addition, suppression of FSH is unable to prevent increases in body fat following the induction of sex steroid deficiency, at least in men. Thus, although the preclinical mouse and human observational data are intriguing, there is currently no direct evidence from interventional studies that FSH regulates bone or fat metabolism in vivo in humans.
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Affiliation(s)
- Sundeep Khosla
- Robert and Arlene Kogod Center on Aging and Endocrine Research Unit, Mayo Clinic College of Medicine, Rochester, Minnesota
- Correspondence: Sundeep Khosla, M.D., College of Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905; Tel: 507-255-6663;
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Antonio L, Priskorn L, Olesen IA, Petersen JH, Vanderschueren D, Jørgensen N. High serum FSH is not a risk factor for low bone mineral density in infertile men. Bone 2020; 136:115366. [PMID: 32304878 DOI: 10.1016/j.bone.2020.115366] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 04/13/2020] [Accepted: 04/14/2020] [Indexed: 12/21/2022]
Abstract
BACKGROUND Male infertility is associated with a higher long-term morbidity and mortality risk. However, it is not clear which diseases are contributing to this risk. Osteoporosis is a possible factor, as it is a frequent disease and sex steroids regulate both fertility and bone health. Furthermore, there are data indicating that high FSH levels in women are related to low bone mineral density (BMD), independent of estradiol levels. As infertile men often have increased FSH, already from a young age, this could be a risk factor for impaired bone health in later life. METHODS One hundred and thirty-seven men with a history of male factor infertility due to spermatogenic failure (SgF men) as well as a control group of 70 men from couples treated with IVF for female factor infertility (non-SgF men) were included in a long-term follow-up study. Men with explained infertility, including testosterone deficiency, were not included. Data from baseline fertility investigations were retrieved from the patient files of the SgF men. At follow-up hormonal and semen analysis were performed and axial, femoral and total body BMD was measured by dual X-ray absorptiometry in all men. Multiple linear regression was used to assess differences between SgF and non-SgF men and to study associations between FSH levels and BMD. RESULTS Median follow-up time was 14.8 years (5th-95th percentile 11.3-18.2) after fertility assessment for SgF men and 15.6 years (12.1-18.5) for non-SgF men (p = 0.033). When comparing the two groups, no significant differences in total T, free T or E2 levels were apparent at follow-up. As expected, LH and FSH were higher in SgF men ((median (5th-95th percentile)) for LH (IU/L): 4.3 (2.2-13.6) for SgF men and 3.0 (1.4-5.8) for non-SgF men (p < 0.001); FSH (IU/L): 9.8 (2.8-35.5) versus 3.7 (1.6-8.7); p < 0.001), and inhibin B and semen parameters were lower in SgF men. There were no differences in BMD between the two groups at follow-up. Furthermore, both groups had median Z-scores close to zero at all sites, indicating that BMD is not different when compared to age-matched healthy men. In SgF men, neither baseline FSH, nor FSH at follow-up, was associated with BMD at the different sites at follow-up. CONCLUSION Men with spermatogenic failure are not at increased risk for impaired bone health when middle aged. Furthermore, infertile men with high FSH levels do not have lower BMD.
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Affiliation(s)
- Leen Antonio
- Department of Chronic Diseases, Metabolism and Ageing (CHROMETA), Laboratory of Clinical and Experimental Endocrinology, KU Leuven, Herestraat 49, B-3000 Leuven, Belgium; Department of Endocrinology, University Hospitals Leuven, Herestraat 49, B-3000 Leuven, Belgium
| | - Lærke Priskorn
- University Department of Growth and Reproduction, Rigshospitalet, Blegdamsvej 9, DK-2100 Copenhagen, Denmark; International Center for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health (EDMaRC), Rigshospitalet, Copenhagen University Hospital, Blegdamsvej 9, DK-2100 Copenhagen, Denmark
| | - Inge A Olesen
- University Department of Growth and Reproduction, Rigshospitalet, Blegdamsvej 9, DK-2100 Copenhagen, Denmark; International Center for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health (EDMaRC), Rigshospitalet, Copenhagen University Hospital, Blegdamsvej 9, DK-2100 Copenhagen, Denmark
| | - Jørgen H Petersen
- University Department of Growth and Reproduction, Rigshospitalet, Blegdamsvej 9, DK-2100 Copenhagen, Denmark; International Center for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health (EDMaRC), Rigshospitalet, Copenhagen University Hospital, Blegdamsvej 9, DK-2100 Copenhagen, Denmark; Department of Biostatistics, Institute of Public Health, University of Copenhagen, Øster Farimagsgade 5, DK-1014 Copenhagen, Denmark
| | - Dirk Vanderschueren
- Department of Chronic Diseases, Metabolism and Ageing (CHROMETA), Laboratory of Clinical and Experimental Endocrinology, KU Leuven, Herestraat 49, B-3000 Leuven, Belgium; Department of Endocrinology, University Hospitals Leuven, Herestraat 49, B-3000 Leuven, Belgium
| | - Niels Jørgensen
- University Department of Growth and Reproduction, Rigshospitalet, Blegdamsvej 9, DK-2100 Copenhagen, Denmark; International Center for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health (EDMaRC), Rigshospitalet, Copenhagen University Hospital, Blegdamsvej 9, DK-2100 Copenhagen, Denmark.
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BK ablation attenuates osteoblast bone formation via integrin pathway. Cell Death Dis 2019; 10:738. [PMID: 31570694 PMCID: PMC6769012 DOI: 10.1038/s41419-019-1972-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 09/04/2019] [Accepted: 09/05/2019] [Indexed: 11/09/2022]
Abstract
Impaired bone formation is one of the major causes of low bone mass and skeletal fragility that occurs in osteoporosis. However, the mechanisms underlying the defects in bone formation are not well understood. Here, we report that big conductance calcium-activated potassium channels (BKs) are required for bone formation and osteoblast function both in vivo and in vitro. By 15 weeks of age, BK knockout (BKO) mice exhibited a decline in bone mineral density and trabecular bone volume of the tibiae and lumbar vertebrae, which were associated with impaired bone formation and osteoblast activity. Mechanistically, BK ablation in bone and bone marrow mesenchymal stem cells (BMSCs) of BKO mice inhibited integrin signaling. Furthermore, the binding of α subunit of BK with integrin β1 protein in osteoblasts was confirmed, and FAK-ERK1/2 signaling was proved to be involved by genetic modification of KCNMA1 (which encodes the α subunit of BK) in ROS17/2.8 osteoblast cells. These findings indicated that BK regulates bone formation by promoting osteoblast differentiation via integrin pathway, which provided novel insight into ion transporter crosstalk with the extracellular matrix in osteoblast regulation and revealed a new potential strategy for intervention in correcting bone formation defects.
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Cauley JA, Ruppert K, Lian Y, Finkelstein JS, Karvonen-Gutierrez CA, Harlow SD, Lo JC, Burnett-Bowie SAM, Karlamangla A, Greendale GA. Serum Sex Hormones and the Risk of Fracture Across the Menopausal Transition: Study of Women's Health Across the Nation. J Clin Endocrinol Metab 2019; 104:2412-2418. [PMID: 30690517 PMCID: PMC6505454 DOI: 10.1210/jc.2018-02047] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 01/18/2019] [Indexed: 11/19/2022]
Abstract
CONTEXT Sex steroid hormones have been linked to fractures in older women. OBJECTIVE To test the hypothesis that hormones measured over the menopausal transition predict fractures. SETTING Seven US clinical centers. SUBJECTS AND MEASUREMENTS Two thousand nine hundred sixty women (average age, 46.4 ± 2.7 years) who had at least two repeat hormone measures and prospective information on fractures. Fasting serum was collected annually for hormone assays. Estradiol (E2) was measured with a modified direct immunoassay. FSH and SHBG were measured with two-site chemiluminescence immunoassays. Hormones were lagged (visit year -1) and transformed using log base 2. Incident fractures were ascertained at each annual visit. All medications including hormone therapy were time varying covariates. Discrete survival methods were used. RESULTS Five hundred eight (17.2%) women experienced an incident fracture over an average follow up of 8.8 ± 4.4 years. Women who experienced an incident fracture were more likely to be white, report high alcohol intake and diabetes, and less likely to report premenopausal status at baseline. A woman whose log E2 was twice that of another had a 10% lower risk of fracture independent of covariates, relative risk (95% CI) = 0.90 (0.82, 0.98). Neither FSH nor SHBG were associated with fractures. CONCLUSIONS Serum E2 levels may help to identify women at higher risk of fractures over the menopausal transition. However, hormone assays must be standardized across laboratories for clinical implementation and further work is needed to define E2 thresholds.
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Affiliation(s)
- Jane A Cauley
- Department of Epidemiology, University of Pittsburgh, Pittsburgh, Pennsylvania
- Correspondence and Reprint Requests: Jane A. Cauley, PhD, Department of Epidemiology, Graduate School of Public Health, 130 DeSoto Street, Pittsburgh, Pennsylvania 15261. E-mail:
| | - Kristine Ruppert
- Department of Epidemiology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Yinjuan Lian
- Department of Epidemiology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | | | | | | | - Joan C Lo
- Kaiser Permanente Northern California Division of Research, Oakland, California
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Chrusciel M, Ponikwicka-Tyszko D, Wolczynski S, Huhtaniemi I, Rahman NA. Extragonadal FSHR Expression and Function-Is It Real? Front Endocrinol (Lausanne) 2019; 10:32. [PMID: 30778333 PMCID: PMC6369633 DOI: 10.3389/fendo.2019.00032] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 01/16/2019] [Indexed: 12/26/2022] Open
Abstract
Expression of the follicle-stimulating hormone receptor (FSHR), besides gonadal tissues, has recently been detected in several extragonadal normal and tumorous tissues, including different types of primary and metastatic cancer and tumor vessel endothelial cells (TVEC). The suggested FSH actions in extragonadal tissues include promotion of angiogenesis, myometrial contractility, skeletal integrity, and adipose tissue accumulation. Non-malignant cells within cancer tissue have been shown to be devoid of FSHR expression, which implies a potential role of FSHR as a diagnostic, prognostic, or even a therapeutic tool. There are shared issues between several of the published reports questioning the validity of some of the conclusion. Firstly, protein expression of FSHR was performed solely with immunohistochemistry (IHC) using either an unavailable "in house" FSHR323 monoclonal antibody or poorly validated polyclonal antibodies, usually without additional methodological quality control and confirmations. Secondly, there is discrepancy between the hardly traceable or absent FSHR gene amplification/transcript data and non-reciprocal strong FSHR protein immunoreactivity. Thirdly, the pharmacological high doses of recombinant FSH used in in vitro studies also jeopardizes the physiological or pathophysiological meaning of the findings. We performed in this review a critical analysis of the results presenting extragonadal expression of FSHR and FSH action, and provide a rationale for the validation of the reported results using additional more accurate and sensitive supplemental methods, including in vivo models and proper positive and negative controls.
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Affiliation(s)
- Marcin Chrusciel
- Institute of Biomedicine, Research Centre for Integrative Physiology and Pharmacology, University of Turku, Turku, Finland
| | | | - Slawomir Wolczynski
- Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Olsztyn, Poland
- Department of Reproduction and Gynecological Endocrinology, Medical University of Bialystok, Bialystok, Poland
| | - Ilpo Huhtaniemi
- Institute of Biomedicine, Research Centre for Integrative Physiology and Pharmacology, University of Turku, Turku, Finland
- Institute of Reproductive and Developmental Biology, Imperial College London, London, United Kingdom
| | - Nafis A. Rahman
- Institute of Biomedicine, Research Centre for Integrative Physiology and Pharmacology, University of Turku, Turku, Finland
- Department of Reproduction and Gynecological Endocrinology, Medical University of Bialystok, Bialystok, Poland
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Kumar TR. Extragonadal Actions of FSH: A Critical Need for Novel Genetic Models. Endocrinology 2018; 159:2-8. [PMID: 29236987 PMCID: PMC5761596 DOI: 10.1210/en.2017-03118] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 11/14/2017] [Indexed: 12/11/2022]
Abstract
Follicle-stimulating hormone (FSH) is critical for ovarian folliculogenesis and essential for female fertility. FSH binds to FSH receptors (FSHRs) and regulates estrogen production in ovarian granulosa cells to orchestrate female reproductive physiology. Ovarian senescence that occurs as a function of aging results in loss of estrogen production, and this is believed to be the major reason for bone loss in postmenopausal women. Although conflicting, studies in rodents and humans during the last decade have provided genetic, pharmacological, and physiological evidence that elevated FSH levels that occur in the face of normal or declining estrogen levels directly regulate bone mass and adiposity. Recently, an efficacious blocking polyclonal FSHβ antibody was developed that inhibited ovariectomy-induced bone loss and triggered white-to-brown fat conversion accompanied by mitochondrial biogenesis in mice. Moreover, additional nongonadal targets of FSH action have been identified, and these include the female reproductive tract (endometrium and myometrium), the placenta, hepatocytes, and blood vessels. In this mini-review, I summarize these studies in mice and humans and discuss critical gaps in our knowledge, yet unanswered questions, and the rationale for developing novel genetic models to unambiguously address the extragonadal actions of FSH.
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Affiliation(s)
- T. Rajendra Kumar
- Division of Reproductive Sciences and Division of Reproductive Endocrinology & Infertility, Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045
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Bousfield GR, May JV, Davis JS, Dias JA, Kumar TR. In Vivo and In Vitro Impact of Carbohydrate Variation on Human Follicle-Stimulating Hormone Function. Front Endocrinol (Lausanne) 2018; 9:216. [PMID: 29867757 PMCID: PMC5960776 DOI: 10.3389/fendo.2018.00216] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 04/17/2018] [Indexed: 12/11/2022] Open
Abstract
Human follicle-stimulating hormone (FSH) exhibits both macro- and microheterogeneity in its carbohydrate moieties. Macroheterogeneity results in three physiologically relevant FSHβ subunit variants, two that possess a single N-linked glycan at either one of the two βL1 loop glycosylation sites or one with both glycans. Microheterogeneity is characterized by 80 to over 100 unique oligosaccharide structures attached to each of the 3 to 4 occupied N-glycosylation sites. With respect to its receptor, partially glycosylated (hypo-glycosylated) FSH variants exhibit higher association rates, greater apparent affinity, and greater occupancy than fully glycosylated FSH. Higher receptor binding-activity is reflected by greater in vitro bioactivity and, in some cases, greater in vivo bioactivity. Partially glycosylated pituitary FSH shows an age-related decline in abundance that may be associated with decreased fertility. In this review, we describe an integrated approach involving genetic models, in vitro signaling studies, FSH biochemistry, relevance of physiological changes in FSH glycoform abundance, and characterize the impact of FSH macroheterogeneity on fertility and reproductive aging. We will also address the controversy with regard to claims of a direct action of FSH in mediating bone loss especially at the peri- and postmenopausal stages.
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Affiliation(s)
- George R. Bousfield
- Department of Biological Sciences, Wichita State University, Wichita, KS, United States
- *Correspondence: George R. Bousfield,
| | - Jeffrey V. May
- Department of Biological Sciences, Wichita State University, Wichita, KS, United States
| | - John S. Davis
- Department of Obstetrics and Gynecology, University of Nebraska Medical Center, Omaha, NE, United States
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, United States
- Nebraska-Western Iowa Health Care System, Omaha, NE, United States
| | - James A. Dias
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, NY, United States
| | - T. Rajendra Kumar
- Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
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Chin KY. The Relationship between Follicle-stimulating Hormone and Bone Health: Alternative Explanation for Bone Loss beyond Oestrogen? Int J Med Sci 2018; 15:1373-1383. [PMID: 30275766 PMCID: PMC6158655 DOI: 10.7150/ijms.26571] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Accepted: 08/27/2018] [Indexed: 11/05/2022] Open
Abstract
Bone loss in women commences before the onset of menopause and oestrogen deficiency. The increase of follicle-stimulating hormone (FSH) precedes oestrogen decline and may be a cause for bone loss before menopause. This review summarizes the current evidence on the relationship between FSH and bone derived from cellular, animal and human studies. Cellular studies found that FSH receptor (FSHR) was present on osteoclasts, osteoclast precursors and mesenchymal stem cells but not osteoblasts. FSH promoted osteoclast differentiation, activity and survival but exerted negligible effects on osteoblasts. Transgenic FSHR or FSH knockout rodents showed heterogenous skeletal phenotypes. Supplementation of FSH enhanced bone deterioration and blocking of FSH action protected bone of rodents. Human epidemiological studies revealed a negative relationship between FSH and bone health in perimenopausal women and elderly men but the association was attenuated in postmenopausal women. In conclusion, FSH may have a direct action on bone health independent of oestrogen by enhancing bone resorption. Its effects may be attenuated in the presence of overt sex hormone deficiency. More longitudinal studies pertaining to the effects of FSH on bone health, especially on fracture risk, should be conducted to validate this speculation.
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Affiliation(s)
- Kok-Yong Chin
- Department of Pharmacology, Faculty of Medicine, Universiti Kebangsaan Malaysia Medical Centre, Malaysia
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15
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Guo C, Li C, Yang K, Kang H, Xu X, Xu X, Deng L. Increased EZH2 and decreased osteoblastogenesis during local irradiation-induced bone loss in rats. Sci Rep 2016; 6:31318. [PMID: 27499068 PMCID: PMC4976370 DOI: 10.1038/srep31318] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 07/05/2016] [Indexed: 01/06/2023] Open
Abstract
Radiation therapy is commonly used to treat cancer patients but exhibits adverse effects, including insufficiency fractures and bone loss. Epigenetic regulation plays an important role in osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). Here, we reported local bone changes after single-dose exposure to 137CS irradiation in rats. Femur bone mineral density (BMD) and trabecular bone volume in the tibia were significantly decreased at 12 weeks after irradiation. Micro-CT results showed that tBMD, Tb.h and Tb.N were also significantly reduced at 12 weeks after irradiation exposure. ALP-positive OB.S/BS was decreased by 42.3% at 2 weeks after irradiation and was decreased by 50.8% at 12 weeks after exposure. In contrast to the decreased expression of Runx2 and BMP2, we found EZH2 expression was significantly increased at 2 weeks after single-dose 137CS irradiation in BMSCs. Together, our results demonstrated that single-dose 137CS irradiation induces BMD loss and the deterioration of bone microarchitecture in the rat skeleton. Furthermore, EZH2 expression increased and osteoblastogenesis decreased after irradiation. The underlying mechanisms warrant further investigation.
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Affiliation(s)
- Changjun Guo
- Shanghai Key Laboratory for the Prevention and Treatment of Bone and Joint Diseases with Integrated Chinese-Western Medicine, Shanghai Institute of Traumatology and Orthopedics, Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine. Address: No. 197, Rui Jin Er Road, Shanghai 200025 China
| | - Changwei Li
- Shanghai Key Laboratory for the Prevention and Treatment of Bone and Joint Diseases with Integrated Chinese-Western Medicine, Shanghai Institute of Traumatology and Orthopedics, Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine. Address: No. 197, Rui Jin Er Road, Shanghai 200025 China
| | - Kai Yang
- Shanghai Key Laboratory for the Prevention and Treatment of Bone and Joint Diseases with Integrated Chinese-Western Medicine, Shanghai Institute of Traumatology and Orthopedics, Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine. Address: No. 197, Rui Jin Er Road, Shanghai 200025 China
| | - Hui Kang
- Shanghai Key Laboratory for the Prevention and Treatment of Bone and Joint Diseases with Integrated Chinese-Western Medicine, Shanghai Institute of Traumatology and Orthopedics, Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine. Address: No. 197, Rui Jin Er Road, Shanghai 200025 China
| | - Xiaoya Xu
- Department of Bone Metabolism, Institute of Radiation Medicine, Fudan University, Shanghai 200032, China. Address: No. 2094, Xietu Road, Shanghai 200032 China
| | - Xiangyang Xu
- Department of Orthopedics, Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine. Address: No. 197, Rui Jin Er Road, Shanghai 200025 China
| | - Lianfu Deng
- Shanghai Key Laboratory for the Prevention and Treatment of Bone and Joint Diseases with Integrated Chinese-Western Medicine, Shanghai Institute of Traumatology and Orthopedics, Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine. Address: No. 197, Rui Jin Er Road, Shanghai 200025 China
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Ulloa-Aguirre A, Zariñán T. The Follitropin Receptor: Matching Structure and Function. Mol Pharmacol 2016; 90:596-608. [DOI: 10.1124/mol.116.104398] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 06/28/2016] [Indexed: 12/19/2022] Open
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Vanderschueren D, Laurent MR, Claessens F, Gielen E, Lagerquist MK, Vandenput L, Börjesson AE, Ohlsson C. Sex steroid actions in male bone. Endocr Rev 2014; 35:906-60. [PMID: 25202834 PMCID: PMC4234776 DOI: 10.1210/er.2014-1024] [Citation(s) in RCA: 184] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Sex steroids are chief regulators of gender differences in the skeleton, and male gender is one of the strongest protective factors against osteoporotic fractures. This advantage in bone strength relies mainly on greater cortical bone expansion during pubertal peak bone mass acquisition and superior skeletal maintenance during aging. During both these phases, estrogens acting via estrogen receptor-α in osteoblast lineage cells are crucial for male cortical and trabecular bone, as evident from conditional genetic mouse models, epidemiological studies, rare genetic conditions, genome-wide meta-analyses, and recent interventional trials. Genetic mouse models have also demonstrated a direct role for androgens independent of aromatization on trabecular bone via the androgen receptor in osteoblasts and osteocytes, although the target cell for their key effects on periosteal bone formation remains elusive. Low serum estradiol predicts incident fractures, but the highest risk occurs in men with additionally low T and high SHBG. Still, the possible clinical utility of serum sex steroids for fracture prediction is unknown. It is likely that sex steroid actions on male bone metabolism rely also on extraskeletal mechanisms and cross talk with other signaling pathways. We propose that estrogens influence fracture risk in aging men via direct effects on bone, whereas androgens exert an additional antifracture effect mainly via extraskeletal parameters such as muscle mass and propensity to fall. Given the demographic trends of increased longevity and consequent rise of osteoporosis, an increased understanding of how sex steroids influence male bone health remains a high research priority.
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Affiliation(s)
- Dirk Vanderschueren
- Clinical and Experimental Endocrinology (D.V.) and Gerontology and Geriatrics (M.R.L., E.G.), Department of Clinical and Experimental Medicine; Laboratory of Molecular Endocrinology, Department of Cellular and Molecular Medicine (M.R.L., F.C.); and Centre for Metabolic Bone Diseases (D.V., M.R.L., E.G.), KU Leuven, B-3000 Leuven, Belgium; and Center for Bone and Arthritis Research (M.K.L., L.V., A.E.B., C.O.), Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, 413 45 Gothenburg, Sweden
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18
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Central genes, pathways and modules that regulate bone mass. Arch Biochem Biophys 2014; 561:130-6. [DOI: 10.1016/j.abb.2014.06.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 06/02/2014] [Accepted: 06/05/2014] [Indexed: 01/07/2023]
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Abstract
Bones are structures in vertebrates that provide support to organs, protect soft organs, and give them shape and defined features, functions that are essential for their survival. To perform these functions, bones are constantly renewed throughout life. The process through which bones are renewed is known as bone remodeling, an energy demanding process sensitive to changes in energy homeostasis of the organism. A close interplay takes place between the diversity of nutritional cues and metabolic signals with different elements of the hypothalamic circuits to co-ordinate energy metabolism with the regulation of bone mass. In this review, we focus on how mouse and human genetics have elucidated the roles of hormonal signals and neural circuits that originate in, or impinge on, the hypothalamus in the regulation of bone mass. This will help to understand the mechanisms whereby regulation of bone is gated and dynamically regulated by the hypothalamus.
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Affiliation(s)
- Kunal Sharan
- Systems Biology of Bone Laboratory, Department of Mouse and Zebrafish Genetics, The Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom
| | - Vijay K Yadav
- Systems Biology of Bone Laboratory, Department of Mouse and Zebrafish Genetics, The Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom; Sanger Mouse Genetics Project, Department of Mouse and Zebrafish Genetics, The Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom.
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Uihlein AV, Finkelstein JS, Lee H, Leder BZ. FSH suppression does not affect bone turnover in eugonadal men. J Clin Endocrinol Metab 2014; 99:2510-5. [PMID: 24646101 PMCID: PMC4079307 DOI: 10.1210/jc.2013-3246] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT In vitro and animal studies have reported conflicting results regarding an independent role for FSH in the regulation of bone turnover. OBJECTIVE Our objective was to test the hypothesis that suppressing serum FSH while holding serum gonadal steroid levels stable in the eugonadal range will affect biochemical markers of bone metabolism in healthy men. PARTICIPANTS, DESIGN, AND SETTING Eugonadal men aged 20 to 50 years participated in this randomized controlled trial at a tertiary care academic teaching hospital. INTERVENTIONS Participants received monthly GnRH analog injections to suppress FSH secretion plus daily topical testosterone gel in prespecified doses (intervention group). Controls received matching placebos (control group). Subjects in the intervention group were individually matched with subjects in the control group to ensure that the mean testosterone and estradiol levels (measured every 4 weeks during the 16-week study period) in the 2 groups were similar. MAIN OUTCOME MEASURES Biochemical markers of bone resorption (serum N-terminal telopeptide and C-terminal telopeptide), bone formation (serum osteocalcin), and FSH were measured at baseline and after 16 weeks of treatment. RESULTS Serum FSH declined by 2% in the control group and by 60% in the intervention group (P < .0001 for the between-group difference). Despite the substantial suppression of serum FSH in the intervention group, serum N-terminal telopeptide, C-terminal telopeptide, and osteocalcin did not change in the intervention group, nor were any between-group differences observed. CONCLUSION When gonadal steroid levels are held constant, short-to midterm suppression of FSH does not affect bone turnover in men. FSH does not appear to be a significant regulator of bone metabolism in eugonadal men.
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Affiliation(s)
- Alexander V Uihlein
- Endocrine Unit (A.V.U., J.S.F., B.Z.L.) and Biostatistics Center (H.L.), Massachusetts General Hospital, Boston, Massachusetts 02114
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Methanol Extract of Euchelus asper Prevents Bone Resorption in Ovariectomised Mice Model. J Osteoporos 2014; 2014:348189. [PMID: 24995144 PMCID: PMC4068096 DOI: 10.1155/2014/348189] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 05/10/2014] [Accepted: 05/19/2014] [Indexed: 12/12/2022] Open
Abstract
Marine molluscs are widely distributed throughout the world and many bioactive compounds exhibiting antiviral, antitumor, antileukemic, and antibacterial activity have been reported worldwide. The present study was designed to investigate the beneficial effect of methanol extract of Euchelus asper (EAME) on estrogen deficiency induced osteoporosis in ovariectomised mice model. Forty-two female Swiss albino mice were randomly assigned into Sham operated (Sham) group and six ovariectomised (OVX) subgroups such as OVX with vehicle (OVX); OVX with estradiol (2 mg/kg/day); OVX with EAME of graded doses (25, 50, 100, and 200 mg/kg/day). Bone turnover markers like serum alkaline phosphatase (ALP), serum acid phosphatase (ACP), serum calcium, and histological investigations of tibia and uterus were analysed. Metaphyseal DNA content of the femur bone was also studied. Antiosteoclastogenic activity of EAME was examined. Administration of EAME was able to reduce the increased bone turnover markers in the ovariectomised mice. Histomorphometric analysis revealed an increase in bone trabeculation and restoration of trabecular separation by EAME treatment. Metaphyseal DNA content of the femur of the OVX mice was increased by EAME administration. EAME also showed a potent antiosteoclastogenic behaviour. Thus, the present study reveals that EAME was able to successfully reduce the estrogen deficiency induced bone loss.
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FSH and TSH in the regulation of bone mass: the pituitary/immune/bone axis. Clin Dev Immunol 2013; 2013:382698. [PMID: 23818914 PMCID: PMC3683445 DOI: 10.1155/2013/382698] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 05/17/2013] [Accepted: 05/17/2013] [Indexed: 11/21/2022]
Abstract
Recent evidences have highlighted that the pituitary hormones have profound effects on bone, so that the pituitary-bone axis is now becoming an important issue in the skeletal biology. Here, we discuss the topical evidence about the dysfunction of the pituitary-bone axis that leads to osteoporotic bone loss. We will explore the context of FSH and TSH hormones arguing their direct or indirect role in bone loss. In addition, we will focus on the knowledge that both FSH and TSH have influence on proinflammatory and proosteoclastogenic cytokine expression, such as TNFα and IL-1, underlining the correlation of pituitary-bone axis to the immune system.
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Crandall CJ, Tseng CH, Karlamangla AS, Finkelstein JS, Randolph JF, Thurston RC, Huang MH, Zheng H, Greendale GA. Serum sex steroid levels and longitudinal changes in bone density in relation to the final menstrual period. J Clin Endocrinol Metab 2013; 98:E654-63. [PMID: 23443812 PMCID: PMC3615209 DOI: 10.1210/jc.2012-3651] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Accepted: 01/29/2013] [Indexed: 01/23/2023]
Abstract
CONTEXT The associations of serum sex steroid and FSH levels with change of bone mineral density (BMD) across the complete menopausal transition are incompletely understood. OBJECTIVE The objective of the study was to examine the associations of annual serum levels of FSH, estradiol (E2), T, and SHBG with the rates of bone loss in 3 phases: pretransmenopausal [baseline to 1 year before the final menstrual period (FMP)], transmenopausal (1 year before to 2 years after the FMP), later postmenopausal (≥ 2 years after the FMP). DESIGN The design of the study was a repeated-measures, mixed-effects regression. SETTING This was a community-based observational study, with a 10-year follow-up. PARTICIPANTS A total of 720 participants of the Study of Women's Health Across the Nation Bone Study participated in the study. OUTCOME MEASURES Annualized lumbar spine (LS) and femoral neck (FN) BMD decline was measured. RESULTS The mean annual change in BMD was slowest in pretransmenopause (0.27%/year in FN) and fastest in transmenopause (2.16%/year in LS). In the pretransmenopausal phase, for every doubling of FSH level, LS BMD change was faster by -0.32%/year (P < .0001). In the transmenopausal phase, for every doubling of FSH level, LS BMD change was -0.35%/year faster (P < .0001); for every doubling of SHBG level, LS BMD change was -0.36%/year faster (P < .0001). In the later postmenopausal phase, for each doubling of the E2 level, the LS BMD change was slower by +0.26%/year (P = .049); for each SHBG doubling, the LS BMD change was 0.21%/year slower (P = .048). The FN associations were weaker and inconsistent. CONCLUSIONS Higher E2 levels and lower FSH levels were associated with lower rates of LS bone loss in some but not all menopausal transition phases.
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Affiliation(s)
- Carolyn J Crandall
- Divisions of General Internal Medicine, Department of Medicine, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90024, USA.
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Abstract
BACKGROUND Although data from rodent systems are extremely useful in providing insights into possible mechanisms of age-related bone loss, concepts evolving from animal models need to ultimately be tested in humans. METHODS This review provides an update on mechanisms of age-related bone loss in humans based on the author's knowledge of the field and focused literature reviews. RESULTS Novel imaging, experimental models, biomarkers, and analytic techniques applied directly to human studies are providing new insights into the patterns of bone mass acquisition and loss as well as the role of sex steroids, in particular estrogen, on bone metabolism and bone loss with aging in women and men. These studies have identified the onset of trabecular bone loss at multiple sites that begins in young adulthood and remains unexplained, at least based on current paradigms of the mechanisms of bone loss. In addition, estrogen appears to be a major regulator of bone metabolism not only in women but also in men. Studies assessing mechanisms of estrogen action on bone in humans have identified effects of estrogen on RANKL expression by several different cell types in the bone microenvironment, a role for TNF-α and IL-1β in mediating effects of estrogen deficiency on bone, and possible regulation of the Wnt inhibitor, sclerostin, by estrogen. CONCLUSIONS There have been considerable advances in our understanding of age-related bone loss in humans. However, there are also significant gaps in knowledge, particularly in defining cell autonomous changes in bone in human studies to test or validate concepts emerging from studies in rodents. Decision Editor: Luigi Ferrucci, MD, PhD.
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Affiliation(s)
- Sundeep Khosla
- Guggenheim 7 , College of Medicine, Mayo Clinic, 200 First Street SW, Rochester, Minnesota 55905.
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Bian C, Zhu K, Yang L, Lin S, Li S, Su B, Zhang J. Gonadectomy differentially regulates steroid receptor coactivator-1 and synaptic proteins in the hippocampus of adult female and male C57BL/6 mice. Synapse 2012; 66:849-57. [PMID: 22623226 DOI: 10.1002/syn.21574] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Accepted: 05/14/2012] [Indexed: 02/06/2023]
Abstract
Hippocampus is one of the most important structures that mediates learning and memory, cognition, and mental behaviors and profoundly regulated by sex hormones in a sex-specific manner, but the mechanism of underlying sex differences regulation is still unclear. We have previously reported that in the male and female mice, steroid receptor coactivator-1 (SRC-1) and some key synaptic proteins share similar developmental profile in the hippocampus, but how circulating sex hormones affect hippocampal SRC-1 as well as these synaptic proteins remain unclear. In this study, we examined how gonad sex hormones regulate hippocampal SRC-1, synaptophysin, PSD-95, and AMPA receptor subtype GluR1 by using immunohistochemistry and Western blot. The results showed that in the female mice, ovariectomy affected hippocampal SRC-1 and GluR1 were only detected at 2 weeks post operation, then it recovered to sham level; synaptophysin was unaffected at any timepoint examined; significant decrease of PSD-95 was only detected at 4 weeks post operation. However, in the male hippocampus, SRC-1 and PSD-95 were decreased from one week and lasted to 4 weeks after orchidectomy, GluR1 decreased from 2 weeks after orchidectomy, but synaptophysin remained unchanged as in the females. Correlation analysis showed the profiles of SRC-1 were positively correlated with GluR1 of the females, PSD-95 and GluR1 of the males, respectively. The above results suggested a distinct regulatory mode between female and male gonad hormones in the regulation of hippocampal SRC-1 and synaptic proteins, which may be one of the mechanisms contributing to the dimorphism of hippocampus during development and ageing.
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Affiliation(s)
- Chen Bian
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing 400038, China
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Smith ER, Yeasky T, Wei JQ, Miki RA, Cai KQ, Smedberg JL, Yang WL, Xu XX. White spotting variant mouse as an experimental model for ovarian aging and menopausal biology. Menopause 2012; 19:588-96. [PMID: 22228319 PMCID: PMC3326177 DOI: 10.1097/gme.0b013e318239cc53] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Menopause is a unique phenomenon in modern women, as most mammalian species possess a reproductive period comparable with their life span. Menopause is caused by the depletion of germ cell-containing ovarian follicles and in laboratory studies is usually modeled in animals in which the ovarian function is removed through ovariectomy or chemical poisoning of the germ cells. Our objective was to explore and characterize the white spotting variant (Wv) mice that have reduced ovarian germ cell abundance, a result of a point mutation in the c-kit gene that decreases kinase activity, as a genetic model for use in menopause studies. METHODS Physiological and morphological features associated with menopause were determined in female Wv/Wv mice compared with age-matched wildtype controls. Immunohistochemistry was used to evaluate the presence and number of follicles in paraffin-embedded ovaries. Bone density and body composition were evaluated using the PIXImus x-ray densitometer, and lipids, calcium, and hormone levels were determined in serum using antigen-specific enzyme immunoassays. Heart and body weight were measured, and cardiac function was evaluated using transthoracic echocardiography. RESULTS The ovaries of the Wv/Wv females have a greatly reduced number of normal germ cells at birth compared with wildtype mice. The remaining follicles are depleted by around 2 months, and the ovaries develop benign epithelial lesions that resemble morphological changes that occur during ovarian aging, whereas a normal mouse ovary has numerous follicles at all stages of development and retains some follicles even in advanced age. Wv mice have elevated plasma gonadotropins and reduced estrogen and progesterone levels, a significant reduction in bone mass density, and elevated serum cholesterol and lipoprotein levels. Moreover, the Wv female mice have enlarged hearts and reduced cardiac function. CONCLUSIONS The reduction of c-kit activity in Wv mice leads to a substantially diminished follicular endowment in newborn mice and premature depletion of follicles in young mice, although mutant females have a normal life span after cessation of ovarian function. The Wv female mice exhibit consistent physiological changes that resemble common features of postmenopausal women. These alterations include follicle depletion, morphological aging of the ovary, altered serum levels of cholesterol, gonadotropins and steroid hormones, decreased bone density, and reduced cardiac function. These changes were not observed in male mice, either age-matched male Wv/Wv or wildtype mice, and are improbably caused by global loss of c-kit function. The Wv mouse may be a genetic, intact-ovary model that mimics closely the phenotypes of human menopause to be used for further studies to understand the mechanisms of menopausal biology.
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Affiliation(s)
- Elizabeth R Smith
- Sylvester Comprehensive Cancer Center, Department ofMedicine, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
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Zhu LL, Tourkova I, Yuen T, Robinson LJ, Bian Z, Zaidi M, Blair HC. Blocking FSH action attenuates osteoclastogenesis. Biochem Biophys Res Commun 2012; 422:54-8. [PMID: 22561017 DOI: 10.1016/j.bbrc.2012.04.104] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Accepted: 04/20/2012] [Indexed: 12/24/2022]
Abstract
A direct effect of FSH on bone turnover via stimulation of osteoclast formation has been reported. Here we show that monoclonal or polyclonal antibodies to FSH inhibit osteoclast formation induced by FSH to an extent similar to that noted in FSH receptor (FSHR) knockout cells. Furthermore, we document the amplification of FSHR cDNA from well-characterized human CD14+ osteoclast precursors and osteoclasts, and the direct sequencing of the PCR products to definitively establish the expression of FSHRs. At these sites, the FSHR was expressed predominantly as an isoform that omits exon 9, a linker between the FSH-binding region and a long, invariant signaling domain of the receptor. These data provide compelling evidence for expression of a FSH receptor isoform in osteoclasts and their precursors.
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Affiliation(s)
- Ling-Ling Zhu
- School of Stomatology, Wuhan University, Wuhan, China
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Gourlay ML, Specker BL, Li C, Hammett-Stabler CA, Renner JB, Rubin JE. Follicle-stimulating hormone is independently associated with lean mass but not BMD in younger postmenopausal women. Bone 2012; 50:311-6. [PMID: 22086136 PMCID: PMC3246561 DOI: 10.1016/j.bone.2011.11.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Revised: 10/11/2011] [Accepted: 11/01/2011] [Indexed: 12/30/2022]
Abstract
PURPOSE Increased follicle-stimulating hormone (FSH) has been associated with lower bone mineral density (BMD) in animal models and longitudinal studies of women, but a direct effect has not been demonstrated. METHODS We tested associations between FSH, non-bone body composition measures and BMD in 94 younger (aged 50 to 64 years) postmenopausal women without current use of hormone therapy, adjusting for sex hormone concentrations and clinical risk factors for osteoporosis. Lean mass, fat mass and areal BMD (aBMD) at the spine, femoral neck and total hip were measured using dual energy X-ray absorptiometry (DXA). Volumetric BMD (vBMD) was measured at the distal radius using peripheral quantitative computed tomography (pQCT). RESULTS FSH was inversely correlated with lean and fat mass, bioavailable estradiol, spine and hip aBMD, and vBMD at the ultradistal radius. In the multivariable analysis, FSH was independently associated with lean mass (β=-0.099, p=0.005) after adjustment for age, race, years since menopause, bioavailable estradiol, bioavailable testosterone, LH, PTH, SHBG and urine N-telopeptide. FSH showed no statistically significant association with aBMD at any site or pQCT measures at the distal radius in adjusted models. Race was independently associated with aBMD, and race and urine N-telopeptide were independently associated with bone area and vBMD. CONCLUSIONS After adjustment for hormonal measures and osteoporosis risk factors, higher concentrations of FSH were independently associated with lower lean mass, but not with BMD. Previously reported correlations between FSH and BMD might have been due to indirect associations via lean mass or weight.
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Affiliation(s)
- Margaret L Gourlay
- Department of Family Medicine, University of North Carolina, Chapel Hill, NC 27599-7595, USA.
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Casarini L, Pignatti E, Simoni M. Effects of polymorphisms in gonadotropin and gonadotropin receptor genes on reproductive function. Rev Endocr Metab Disord 2011; 12:303-21. [PMID: 21912887 DOI: 10.1007/s11154-011-9192-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Gonadotropins, the action of which is mediated at the level of their gonadal receptors, play a key role in sexual development, reproductive functions and in metabolism. The involvement of the gonadotropins and their receptor genotypes on reproductive function are widely studied. A large number of gonadotropins and their receptors gene polymorphisms are known, but the only one considerable as a clear, absolute genetic marker of reproductive features or disfunctions is the FSHR Asn680Ser polymorphism, since it modulates ovarian response to FSH. The aim of these studies would to be the prediction of the genetic causes of sex-related diseases to enable a customized clinical setting based on individual response of patients undergoing gonadotropin stimulation. In this review we discuss the latest information about the effects of polymorphisms of the gonadotropins and their receptor genes on reproductive functions of both male and female, and discuss their patho-physiological implications.
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Affiliation(s)
- Livio Casarini
- Department of Medicine, Endocrinology, Metabolism and Geriatrics, University of Modena and Reggio Emilia, via P. Giardini 1355, 41126 Modena, Italy
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Gourlay ML, Preisser JS, Hammett-Stabler CA, Renner JB, Rubin J. Follicle-stimulating hormone and bioavailable estradiol are less important than weight and race in determining bone density in younger postmenopausal women. Osteoporos Int 2011; 22:2699-708. [PMID: 21125395 PMCID: PMC3109215 DOI: 10.1007/s00198-010-1505-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Accepted: 11/15/2010] [Indexed: 10/18/2022]
Abstract
UNLABELLED The association between follicle-stimulating hormone (FSH) and bone density was tested in 111 postmenopausal women aged 50-64 years. In the multivariable analysis, weight and race were important determinants of bone mineral density. FSH, bioavailable estradiol, and other hormonal variables did not show statistically significant associations with bone density at any site. INTRODUCTION FSH has been associated with bone density loss in animal models and longitudinal studies of women. Most of these analyses have not considered the effect of weight or race. METHODS We tested the association between FSH and bone density in younger postmenopausal women, adjusting for patient-related factors. In 111 postmenopausal women aged 50-64 years, areal bone mineral density (BMD) was measured at the lumbar spine, femoral neck, total hip, and distal radius using dual-energy X-ray absorptiometry, and volumetric BMD was measured at the distal radius using peripheral quantitative computed tomography (pQCT). Height, weight, osteoporosis risk factors, and serum hormonal factors were assessed. RESULTS FSH inversely correlated with weight, bioavailable estradiol, areal BMD at the lumbar spine and hip, and volumetric BMD at the ultradistal radius. In the multivariable analysis, no hormonal variable showed a statistically significant association with areal BMD at any site. Weight was independently associated with BMD at all central sites (p < 0.001), but not with BMD or pQCT measures at the distal radius. Race was independently associated with areal BMD at all sites (p ≤ 0.008) and with cortical area at the 33% distal radius (p = 0.004). CONCLUSIONS Correlations between FSH and bioavailable estradiol and BMD did not persist after adjustment for weight and race in younger postmenopausal women. Weight and race were more important determinants of bone density and should be included in analyses of hormonal influences on bone.
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Affiliation(s)
- M L Gourlay
- Department of Family Medicine, University of North Carolina, Chapel Hill, NC 27599-7595, USA.
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Gaddy D, Fowler TW, Suva LJ. Hormonal causes of menopausal bone resorption. Curr Osteoporos Rep 2011; 9:43-5. [PMID: 21487955 DOI: 10.1007/s11914-011-0055-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Dana Gaddy
- Departments of Physiology & Biophysics, University of Arkansas for Medical Sciences, 4301 West Markham Street, Little Rock, AR 72205, USA.
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Khosla S, Melton LJ, Riggs BL. The unitary model for estrogen deficiency and the pathogenesis of osteoporosis: is a revision needed? J Bone Miner Res 2011; 26:441-51. [PMID: 20928874 PMCID: PMC3179298 DOI: 10.1002/jbmr.262] [Citation(s) in RCA: 233] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Over a decade ago, we proposed a "unitary" model for the pathogenesis of osteoporosis that identified estrogen deficiency as the predominant cause of both the early, accelerated, and late slow phases of bone loss in postmenopausal women and as a contributing cause of the continuous phase of bone loss in aging men. While this was a plausible model then, new data over the intervening years suggest a need to modify these concepts. Indeed, based largely on rodent studies, a "revisionist" view of the pathogenesis of osteoporosis has been proposed recently that attempts a paradigm shift from the estrogen-centric model to one in which bone loss is largely independent of estrogen deficiency and is driven instead by cell-autonomous age-related factors. However, detailed clinical investigative studies using quantitative computed tomography demonstrate that the onset of cortical bone loss in humans is closely tied to estrogen deficiency; thus the estrogen-centric view is likely correct for cortical bone, which comprises over 80% of the skeleton and is the major structural determinant of fracture risk at most skeletal sites. By contrast, these same studies also demonstrate that trabecular bone loss begins in sex hormone-replete young adults of both sexes. This suggests that a significant proportion of trabecular bone loss is either estrogen-independent or, as suggested by some studies, requires higher levels for its regulation. In this perspective, we critically review these and other findings, leading us to conclude that our original model requires modification but not revision.
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Affiliation(s)
- Sundeep Khosla
- Endocrine Research Unit, College of Medicine, Mayo Clinic, Rochester, MN 55905, USA.
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Rouach V, Katzburg S, Koch Y, Stern N, Somjen D. Bone loss in ovariectomized rats: Dominant role for estrogen but apparently not for FSH. J Cell Biochem 2011; 112:128-37. [DOI: 10.1002/jcb.22908] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Handelsman DJ. RFD Award Lecture 2010.Hormonal regulation of spermatogenesis: insights from constructing genetic models. Reprod Fertil Dev 2011; 23:507-19. [DOI: 10.1071/rd10308] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2010] [Accepted: 12/23/2010] [Indexed: 11/23/2022] Open
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Abstract
Elevated follicle-stimulating hormone (FSH) activity is proposed to directly cause bone loss independent of estradiol deficiency in aging women. Using transgenic female mice expressing human FSH (TgFSH), we now reveal that TgFSH dose-dependently increased bone mass, markedly elevating tibial and vertebral trabecular bone volume. Furthermore, TgFSH stimulated a striking accrual of bone mass in hypogonadal mice lacking endogenous FSH and luteinizing hormone (LH) function, showing that FSH-induced bone mass occurred independently of background LH or estradiol levels. Higher TgFSH levels increased osteoblast surfaces in trabecular bone and stimulated de novo bone formation, filling marrow spaces with woven rather than lamellar bone, reflective of a strong anabolic stimulus. Trabecular bone volume correlated positively with ovarian-derived serum inhibin A or testosterone levels in TgFSH mice, and ovariectomy abolished TgFSH-induced bone formation, proving that FSH effects on bone require an ovary-dependent pathway. No detectable FSH receptor mRNA in mouse bone or cultured osteoblasts or osteoclasts indicated that FSH did not directly stimulate bone. Therefore, contrary to proposed FSH-induced bone loss, our findings demonstrate that FSH has dose-dependent anabolic effects on bone via an ovary-dependent mechanism, which is independent of LH activity, and does not involve direct FSH actions on bone cells.
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Abstract
Osteoporosis, a global health problem, is now frequently recognized to be secondary to alterations in the pituitary-bone axis. This review examines the current evidence for how dysregulation of the pituitary-bone axis leads to osteoporotic bone loss. Specifically, perimenopausal bone loss in the context of follicle-stimulating hormone action, and hyperthyroid bone loss in the context of thyroid-stimulating hormone action are explored. From the reviewed scientific findings, recommendations for early diagnosis and better clinical management of bone loss are made.
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Affiliation(s)
- Manasi Agrawal
- Department of Medicine, Mount Sinai School of Medicine, New York, NY 10029, USA.
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Drake MT, McCready LK, Hoey KA, Atkinson EJ, Khosla S. Effects of suppression of follicle-stimulating hormone secretion on bone resorption markers in postmenopausal women. J Clin Endocrinol Metab 2010; 95:5063-8. [PMID: 20610587 PMCID: PMC2968737 DOI: 10.1210/jc.2010-1103] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT It has recently been proposed that the increase in bone resorption after the menopause may not be due principally to estrogen deficiency but rather to the concomitant increase in circulating FSH levels. OBJECTIVE The objective of the study was to test whether suppression of FSH secretion in postmenopausal women reduces levels of bone resorption markers. DESIGN This was a prospective study. SETTING The study was conducted at a clinical research unit. PARTICIPANTS AND INTERVENTIONS Postmenopausal women were treated with a GnRH agonist (leuprolide acetate, 7.5 mg im every 28 d; n = 21) or placebo injections (control; n = 20). Both groups received the aromatase inhibitor, letrozole, 2.5 mg/d, to eliminate variations in endogenous estrogen levels as a confounder. MAIN OUTCOME MEASURES Serum FSH and bone resorption markers [serum C-terminal telopeptide of type I collagen (CTX) and tartrate-resistant acid phosphatase 5b (TRAP5b)] at d 105 (3.5 months) of treatment as compared with baseline. RESULTS Compared with baseline, serum FSH levels did not change significantly in controls (+6%) but were reduced (-86%, into the premenopausal range) in the GnRH group. Due to the aromatase inhibitor-induced reduction in estrogen production, serum CTX and TRAP5b levels increased significantly in controls (+20 and +10%, respectively). In the GnRH group, suppression of FSH secretion did not reduce serum CTX or TRAP5b levels; rather, both markers also increased in these women (+34 and +15%, respectively; P = 0.161 and 0.266 for comparison of percent changes between groups). CONCLUSIONS This direct interventional study demonstrates that FSH does not regulate bone resorption in postmenopausal women.
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Affiliation(s)
- Matthew T Drake
- Division of Endocrinology and Metabolism, College of Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA
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Abstract
Hypothalamic gonadotropin-releasing hormone (GnRH) stimulates secretion of pituitary luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which directly regulate ovarian function. Pituitary FSH can modulate osteoclast development, and thereby influence bone turnover. Pituitary oxytocin and prolactin effects on the skeleton are not merely limited to pregnancy and lactation; oxytocin stimulates osteoblastogenesis and bone formation, whereas prolactin exerts skeletal effects in an age-dependent manner. Cyclic levels of inhibins and estrogen suppress FSH and LH, respectively, and also suppress bone turnover via their suppressive effects on osteoblast and osteoclast differentiation. However, continuous exposure to inhibins or estrogen/androgens is anabolic for the skeleton in intact animals and protects against gonadectomy-induced bone loss. Alterations of one hormone in the hypothalamic-pituitary-gonadal (HPG) axis influence other bone-active hormones in the entire feedback loop in the axis. Thus, we propose that the action of the HPG axis should be extended to include its combined effects on the skeleton, thus creating the HPG skeletal (HPGS) axis.
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Affiliation(s)
- Kristy M Nicks
- Departments of Physiology and Biophysics and Orthopaedic Surgery, University of Arkansas for Medical Sciences, 4301 West Markham, Slot 505, Little Rock, AR, 72205, USA.
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Abstract
OBJECTIVE To review new discoveries that revisit our current thinking on the genesis of osteoporosis using hypogonadal and thyrotoxic bone loss as examples. METHODS We focus on cell biologic, mouse genetic, and human studies that have established a direct action of the interior pituitary hormones follicle-stimulating hormone and thyrotropin on the skeleton and discuss emerging clinical evidence for a novel pituitary-bone axis in humans that bypasses master endocrine organs, namely the ovaries and thyroid gland. RESULTS The cataloguing of human mutations, the use of genetically modified mice that recapitulate human disease, and the rapid growth of genomic sciences have together had a profound impact on how basic research is translated into clinical practice. The skeleton has become a paradigm for the application of such advances to an extent that hitherto unrecognized physiologic and pathophysiologic findings have emerged. We propose that hypogonadal and thyrotoxic bone loss are not solely due to changes in the level of master hormones, but instead also arise from the direct action of anterior pituitary hormones on the skeleton. CONCLUSIONS We predict a pituitary-bone axis in which pituitary hormones bypass traditional endocrine targets to affect the skeleton directly with remarkable sensitivity. New therapeutic targets thus become a likely possibility.
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Affiliation(s)
- Mone Zaidi
- Mount Sinai Bone Program, Mount Sinai School of Medicine, New York, New York 10029 , USA.
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Tang WJ, Wang LF, Xu XY, Zhou Y, Jin WF, Wang HF, Gao J. Autocrine/paracrine action of vitamin D on FGF23 expression in cultured rat osteoblasts. Calcif Tissue Int 2010; 86:404-10. [PMID: 20354682 DOI: 10.1007/s00223-010-9355-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Accepted: 03/11/2010] [Indexed: 10/19/2022]
Abstract
To explore the local mechanisms of fibroblast growth factor (FGF) 23 regulations, we examined the FGF23 expression patterns in an osteoblast culture model. The characteristics of cultured rat calvaria osteoblasts in half-confluence, confluence, osteoid deposition, and osteoid mineralization stages might reflect the proliferation, differentiation, maturation, and matrix mineralization stages, respectively. Compared with proliferating cells in half-confluence, FGF23 expression was upregulated by 7.5-fold at the mRNA level and 126% at the protein level in confluent differentiated cells as determined by real-time RT-PCR and Western blot analysis. Interestingly, mRNA levels of CYP27B1 (the gene coding for 1alpha-hydroxylase enzyme which catalyses the conversion of 1alpha,25-dihydroxyvitamin D, 1alpha,25[OH]2D, from its inactive form, 25-hydroxycholecalciferol, 25[OH]D) and CYP24A (the gene coding for 24-hydroxylase, a target gene of 1alpha,25[OH]2D) were significantly increased by twofold and 34-fold, respectively, in differentiated osteoblasts compared with proliferating cells. We next examined if the local production of 1alpha,25(OH)2D might contribute to the FGF23 upregulation. We cultured osteoblasts in serum-free medium with or without 25-(OH)D (the substrate of 1alpha-hydroxylase). FGF23 mRNA levels were increased in proliferating cells (16-fold) and in differentiated cells (28-fold) by the physiological dose of 25-(OH)D3 treatment. CYP27B1 was slightly but significantly upregulated and CYP24A was increased by 1,700-fold and 800-fold, respectively, in transcriptional levels. Because FGF23 was upregulated in confluent osteoblasts regardless of the presence or absence of 25-(OH)D in serum-free medium, we further examined the possible impact of cell communication on FGF23 expression. We treated osteoblasts with carbenoxolone, a gap junction Cx43 blocker in serum-free medium. The FGF23 mRNA level was reduced by 50% in confluent differentiated cells and slightly but not significantly reduced in half-confluent cells by carbenoxolone treatments. The results suggested that upregulation of FGF23 in differentiated osteoblast appeared to be due to increased autocrine/paracrine action of osteoblast-derived 1alpha,25(OH)2D and increased cell communication, which were identified in cultured rat calvaria osteoblasts. These results indicate that FGF23 expression was stimulated not only by circulating calcitriol but also by locally produced 1alpha,25(OH)2D. The local mechanisms of FGF23 expression remain to be characterized.
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Affiliation(s)
- Wen-Jing Tang
- Department of Bone Metabolism, Institute of Radiation Medicine, Fudan University, No. 2094 Xie-tu Road, Building 1, Room 407, Shanghai, People's Republic of China.
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Abstract
As for most multifactorial disorders, the pathogenesis of osteoporosis is complex, and a different set of mechanisms may be operative in any given individual. However, there are certain common causes of bone loss and increased fracture risk with aging in most people. These include genetic factors contributing to the acquisition of peak bone mass, illnesses affecting skeletal growth and development, sex steroid deficiency following the menopause in women and with aging in men, and intrinsic, age-related changes in bone metabolism. Superimposed on these factors are specific secondary causes of bone loss, such as corticosteroid use or other illnesses affecting bone metabolism that may contribute to fracture risk in individuals exposed to these factors. The past decade has witnessed tremendous advances in our understanding of each of these various causes of bone loss, leading to the development of novel, mechanism-based therapeutic approaches to prevent and treat this important public health disorder.
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Affiliation(s)
- Sundeep Khosla
- Endocrine Research Unit, College of Medicine, Mayo Clinic, Rochester, MN
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Sun L, Zhang Z, Zhu LL, Peng Y, Liu X, Li J, Agrawal M, Robinson LJ, Iqbal J, Blair HC, Zaidi M. Further evidence for direct pro-resorptive actions of FSH. Biochem Biophys Res Commun 2010; 394:6-11. [PMID: 20171951 PMCID: PMC3144627 DOI: 10.1016/j.bbrc.2010.02.113] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Accepted: 02/17/2010] [Indexed: 11/15/2022]
Abstract
We confirm that FSH stimulates osteoclast formation, function and survival to enhance bone resorption. It does so via the activation of a pertussis toxin-sensitive G(i)-coupled FSH receptor that we and others have identified on murine and human osteoclast precursors and mature osteoclasts. FSH additionally enhances the production of several osteoclastogenic cytokines, importantly TNFalpha, likely within the bone marrow microenvironment, to augment its pro-resorptive action. FSH levels in humans rise before estrogen falls, and this hormonal change coincides with the most rapid rates of bone loss. On the basis of accumulating evidence, we reaffirm that FSH contributes to the rapid peri-menopausal and early post-menopausal bone loss, which might thus be amenable to FSH blockade.
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Affiliation(s)
- Li Sun
- Mount Sinai Bone Program, Mount Sinai School of Medicine, New York, NY 10029
| | - Zhiyuan Zhang
- Mount Sinai Bone Program, Mount Sinai School of Medicine, New York, NY 10029
| | - Ling-Ling Zhu
- Mount Sinai Bone Program, Mount Sinai School of Medicine, New York, NY 10029
| | - Yuanzhen Peng
- Mount Sinai Bone Program, Mount Sinai School of Medicine, New York, NY 10029
| | - Xuan Liu
- Mount Sinai Bone Program, Mount Sinai School of Medicine, New York, NY 10029
| | - Jianhua Li
- Mount Sinai Bone Program, Mount Sinai School of Medicine, New York, NY 10029
| | - Manasi Agrawal
- Mount Sinai Bone Program, Mount Sinai School of Medicine, New York, NY 10029
| | - Lisa J. Robinson
- Department of Pathology, University of Pittsburgh and Pittsburgh VA Medical Center, Pittsburgh PA 15243, USA
| | - Jameel Iqbal
- Mount Sinai Bone Program, Mount Sinai School of Medicine, New York, NY 10029
| | - Harry C. Blair
- Department of Pathology, University of Pittsburgh and Pittsburgh VA Medical Center, Pittsburgh PA 15243, USA
| | - Mone Zaidi
- Mount Sinai Bone Program, Mount Sinai School of Medicine, New York, NY 10029
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Imam A, Iqbal J, Blair HC, Davies TF, Huang CLH, Zallone A, Zaidi M, Sun L. Role of the pituitary-bone axis in skeletal pathophysiology. Curr Opin Endocrinol Diabetes Obes 2009; 16:423-9. [PMID: 19816170 DOI: 10.1097/med.0b013e3283328aee] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW Embedded within textbooks for decades is the hard fact that releasing hormones from the anterior pituitary, namely, follicle-stimulating hormone, thyroid-stimulating hormone and adrenocorticotropic hormone, stimulate master hormone secretion from target endocrine organs. We propose a paradigm shift in endocrine physiology, which is that these hormones act by design on bone directly, also now considered an endocrine organ. RECENT FINDINGS Complementary investigations using mouse genetic and cell biological approaches reveal that follicle-stimulating hormone and thyroid-stimulating hormone act on bone cells directly to regulate bone remodeling and bone mass. Thyroid-stimulating hormone inhibits bone remodeling, whereas follicle-stimulating hormone stimulates it. We also find that the posterior pituitary hormone oxytocin is anabolic to the skeleton. SUMMARY An ambitious extrapolation is that a plurality of pituitary hormones acts in concert as part of a 'pituitary-bone' axis to regulate skeletal integrity in health and disease. When dysregulated master hormone levels during hypogonadism and hyperthyroidism cause altered pituitary hormone secretion through hypothalamic feedback, the latter hormones contribute to the skeletal loss.
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Affiliation(s)
- Aliza Imam
- The Mount Sinai Bone Program, Mount Sinai School of Medicine, New York, New York, USA
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Nicks KM, Perrien DS, Akel NS, Suva LJ, Gaddy D. Regulation of osteoblastogenesis and osteoclastogenesis by the other reproductive hormones, Activin and Inhibin. Mol Cell Endocrinol 2009; 310:11-20. [PMID: 19615428 PMCID: PMC2951729 DOI: 10.1016/j.mce.2009.07.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2009] [Revised: 07/03/2009] [Accepted: 07/07/2009] [Indexed: 01/30/2023]
Abstract
There is both cellular and physiological evidence demonstrating that both Activins and Inhibins regulate osteoblastogenesis and osteoclastogenesis, and regulate bone mass in vivo. Although Activins and Inhibins were initially isolated from the gonad, Activins are also produced and stored in bone, whereas Inhibins exert their regulation on bone cell differentiation and metabolism via endocrine effects. The accumulating data provide evidence that reproductive hormones, distinct from classical sex steroids, are important regulators of bone mass and bone strength. Given the well described dominant antagonism of Inhibin over Activin, as well as over BMPs and TGFbeta, the gonadally derived Inhibins are important regulators of locally produced osteotrophic factors. Thus, the cycling Inhibins in females and diurnal changes in Inhibin B in males elicit temporal shifts in Inhibin levels (tone) that de-repress the pituitary. This fundamental action has the potential to de-repress locally stimulated changes in osteoblastogenesis and osteoclastogenesis, thereby altering bone metabolism.
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Affiliation(s)
- Kristy M. Nicks
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Daniel S. Perrien
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
- Center for Bone Biology and Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Nisreen S. Akel
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Larry J Suva
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
- Department of Orthopaedic Surgery, Center for Orthopaedic Research, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Dana Gaddy
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
- Department of Orthopaedic Surgery, Center for Orthopaedic Research, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
- Corresponding Author: Departments of Physiology and Biophysics and Orthopaedic Surgery, University of Arkansas for Medical Sciences, 4301 W. Markham St., Slot 505, Little Rock, AR 72205, 501-686-5918, 501-686-8167 FAX,
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New insights: elevated follicle-stimulating hormone and bone loss during the menopausal transition. Curr Rheumatol Rep 2009; 11:191-5. [PMID: 19604463 DOI: 10.1007/s11926-009-0026-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We hypothesize that a rising follicle-stimulating hormone (FSH) level during the menopausal transition, even in the face of a normal estrogen level, contributes to increased bone resorption and profound bone loss that is accompanied by trabecular perforation and diminished bone strength. FSH has been shown to directly stimulate osteoclast formation and bone resorption, and our murine genetic studies indicate that the absence of FSH can, in part, protect against hypogonadal hyperresorption that causes bone loss. Furthermore, carefully conducted human studies, such as the Study of Women Across Nations (SWAN), indicate strong correlations between serum FSH levels and bone loss. Potential therapeutic implications include the development of antagonists to circulating FSH and its osteoclastic receptor.
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Zaidi M, Iqbal J, Blair HC, Zallone A, Davies T, Sun L. Paradigm Shift in the Pathophysiology of Postmenopausal and Thyrotoxic Osteoporosis. ACTA ACUST UNITED AC 2009; 76:474-83. [DOI: 10.1002/msj.20136] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Abstract
PURPOSE OF REVIEW The present review will focus on the most important recent findings with respect to skeletal androgen action. Many studies have indicated that part of the androgen action may be related to the conversion of androgens into estrogens. Therefore, some of the most recent findings of skeletal estrogen action relevant for male skeletal physiology will also be discussed. RECENT FINDINGS Androgens and estrogens stimulate bone formation and inhibit bone resorption. Sex steroids may interact with different receptors, target cells and other bone anabolic pathways. Androgen receptor and estrogen receptor signalling appear to be important for male bone formation during growth. Sex steroid signalling may involve genomic and nongenomic pathways, interaction with mechanical loading, the growth hormone/insulin-like growth factor-I axis and/or other bone anabolic pathways. Estrogen receptor alpha in osteoclasts appears to regulate bone resorption in women but not men, whereas androgen receptor signalling in osteoblasts may only partly regulate bone resorption in males. SUMMARY The latest developments indicate that androgens and estrogens are important for male bone metabolism and homeostasis and therefore selective estrogen receptor alpha and androgen receptor signalling remain interesting drug targets for the stimulation of bone formation and male skeletal integrity.
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Affiliation(s)
- Dirk Vanderschueren
- Bone Research Unit, Laboratory for Experimental Medicine and Endocrinology, Department of Experimental Medicine, Katholieke Universiteit Leuven, Leuven, Belgium.
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Ritter V, Thuering B, Saint Mezard P, Luong-Nguyen NH, Seltenmeyer Y, Junker U, Fournier B, Susa M, Morvan F. Follicle-stimulating hormone does not impact male bone mass in vivo or human male osteoclasts in vitro. Calcif Tissue Int 2008; 82:383-91. [PMID: 18465073 DOI: 10.1007/s00223-008-9134-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Accepted: 04/15/2008] [Indexed: 11/25/2022]
Abstract
Bone loss in the elderly is mainly caused by osteoclast-induced bone resorption thought to be causally linked to the decline in estrogen and testosterone levels in females and males. Recently, involvement of follicle stimulating-hormone (FSH) in this process has been suggested to explain in part the etiology of the disease in females, whereas its role in males has never been examined. In this study, the direct impact of FSH on bone mass of 16-week-old C57BL/6J male mice by either daily intermittent application of 6 or 60 mug/kg of FSH or continuous delivery via miniosmotic pump of a dose of 6 mug/kg over the course of a month was assessed. Femoral peripheral quantitative computed tomographic and microcomputed tomographic analyses at 0, 2, and 4 weeks of FSH-treated mice did not reveal any differences in cancellous and cortical bone compared to sham-treated mice. FSH functionality was verified by demonstrating cAMP induction and activation of a cAMP-response element-containing reporter cell line by FSH. Furthermore, osteoclastogenesis from human mononuclear cell precursors and from RAW 264.7 cells was not affected by FSH (3, 10, 30 ng/mL) compared to control. No direct effect of FSH on gene regulation was observed by Affymetrix Gene Array on RAW 264.7 cells. Lastly, no expression of FSH receptor (FSHR) mRNA or FSHR was observed by quantitative polymerase chain reaction and Western blot in either human male osteoclasts or RAW 264.7 cells. These data show that FSH does not appear to modulate male bone mass regulation in vivo and does not act directly on osteoclastogenesis in vitro.
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Affiliation(s)
- Veronique Ritter
- Musculoskeletal Disease Area, Novartis Institutes for Biomedical Research, Basel, Switzerland
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Abstract
INTRODUCTION The mechanism(s) by which sex steroids regulate bone turnover in humans are unclear, and recent studies have suggested that follicle-stimulating hormone (FSH) may play an important role in regulating bone resorption. MATERIALS AND METHODS Fifty-nine men (median age, 69 yr) underwent suppression of sex steroids using a gonadotropin-releasing hormone (GnRH) agonist and aromatase blocker and were replaced with testosterone (T; 5 mg/d) and estradiol (E; 37.5 microg/d). After assessment of bone resorption markers (serum C-terminal telopeptide of type I collagen [CTX] and TRACP5b), they were randomized to sex steroid deficiency (-T, -E), E alone (-T, +E), T alone (+T, -E), or both (+T, +E) and restudied 3 wk later. Bone marrow aspirates were obtained to isolate osteoblastic, T, and monocytic cells using magnetic-activated cell sorting. RESULTS Serum CTX and TRACP5b increased significantly (by 71% and 15%, p < 0.01 and < 0.001, respectively) in the -T, -E group, and these increases occurred despite a 60% suppression of serum FSH levels (p < 0.001) caused by the GnRH agonist. There were significant E (but not T) effects on preventing increases in serum CTx and TRACP levels. There was a nonsignificant trend (p = 0.122) for E to suppress RANKL mRNA levels in bone marrow osteoblastic cells. Changes in mRNA levels for other cytokines (TNF-alpha, interleukin (IL)-1alpha, IL-1beta, IL-1ra, IFN-gamma) in bone marrow cells were not significant. CONCLUSIONS E has greater suppressive effects on bone resorption than T, and increased bone resorption after sex steroid deficiency can occur independently of changes in FSH secretion. E effects on bone resorption may be mediated by regulation of RANKL production by osteoblastic cells, although further studies using more highly purified cells may reduce the variability of the mRNA measurements and allow for clearer definition of the mediators of sex steroid action in vivo.
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A population-based assessment of rates of bone loss at multiple skeletal sites: evidence for substantial trabecular bone loss in young adult women and men. J Bone Miner Res 2008; 23:205-14. [PMID: 17937534 PMCID: PMC2665699 DOI: 10.1359/jbmr.071020] [Citation(s) in RCA: 340] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
UNLABELLED Using QCT, we made a longitudinal, population-based assessment of rates of bone loss over life at the distal radius, distal tibia, and lumbar spine. Cortical bone loss began in perimenopause in women and later in life in men. In contrast, trabecular bone loss began in young adulthood in both sexes. INTRODUCTION Although conventional wisdom holds that bone loss begins at menopause in women and later in life in men, this has not been examined longitudinally in population-based studies using precise technology capable of distinguishing cortical and trabecular bone. MATERIALS AND METHODS In an age- and sex-stratified population sample (n = 553), we measured volumetric BMD (vBMD) of trabecular and cortical bone by QCT annually for up to 3 yr at the distal radius (DR) and distal tibia (DT) (n = 552) and trabecular vBMD at baseline and 3 yr at the lumbar spine (LS) (n = 474). RESULTS Substantial cortical bone loss began in middle life in women but began mainly after age 75 in men. In contrast, substantial trabecular bone loss began in young adult women and men at all three skeletal sites and continued throughout life with acceleration during perimenopause in women. Women experienced 37% and men experienced 42% of their total lifetime trabecular bone loss before age 50 compared with 6% and 15%, respectively, for cortical bone. Median rates of change in trabecular bone (%/yr) were -0.40, -0.24, and -1.61 in young adult women and -0.38, -0.40, and -0.84 in young adult men at the DR, DT, and LS, respectively (all p < 0.001). The early trabecular bone loss did not consistently correlate with putative causal factors, except for a trend with IGF-related variables at DT in women. However, in postmenopausal women and, to a lesser extent, in older men, higher rates of cortical and trabecular bone loss were associated with lower levels of biologically-active sex steroids and with higher levels of follicle-stimulating hormone and bone turnover markers. CONCLUSIONS The late onset of cortical bone loss is temporally associated with sex steroid deficiency. However, the early-onset, substantial trabecular bone loss in both sexes during sex steroid sufficiency is unexplained and indicates that current paradigms on the pathogenesis of osteoporosis are incomplete.
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