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Rathod B, Desai S, Samvelyan HJ, Bock L, Wu J, Ohlsson C, Palmquist A, Alm JJ, Newton PT, Andersson G, Windahl SH. Tartrate-resistant acid phosphatase (TRAP/ACP5) promotes bone length, regulates cortical and trabecular bone mass, and maintains growth plate architecture and width in a sex- and site-specific manner in mice. Bone 2024; 188:117223. [PMID: 39111379 DOI: 10.1016/j.bone.2024.117223] [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: 06/03/2024] [Revised: 08/01/2024] [Accepted: 08/02/2024] [Indexed: 09/09/2024]
Abstract
Tartrate-resistant acid phosphatase (TRAP) serum levels reflect osteoclast number, bone remodeling activity, and fracture risk. Deletion or loss of function of TRAP results in short stature in mice and man. Yet, the impact and mechanisms of TRAP for the site- and sex-specific development of bone and cartilage is not well understood. Here, we use a global TRAP knockout (TRAPKO) and wildtype littermate control (WT) mice of both sexes to investigate TRAP as a possible sex- and site-specific regulator of bone and growth plate development. TRAPKO mice of both sexes weighed less and had shorter tibial length than their WT, features that were more accentuated in male than female TRAPKO mice. These changes were not associated with a general reduction in growth as not all organs displayed a proportionally lower mass, and serum IGF-1 was unchanged. Using μCT and site-specificity analysis of the cortical bone revealed wider proximal tibia, a higher trabecular thickness, and lower trabecular separation in male TRAPKO compared to WT mice, an effect not seen in female mice. Histomorphometric analysis revealed that the growth plate height as well as height of terminal hypertrophic chondrocytes were markedly increased, and the number of columns was decreased in TRAPKO mice of both sexes. These effects were more accentuated in female mice. Proliferation and differentiation of bone marrow derived macrophages into osteoclasts, as well as C-terminal cross links were normal in TRAPKO mice of both sexes. Collectively, our results show that TRAP regulates bone and cartilage development in a sex-and site-specific manner in mice.
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Affiliation(s)
- Bhavik Rathod
- Karolinska Institutet, Department of Laboratory Medicine, Division of Pathology, Huddinge, Sweden; Karolinska Institutet, Department of Microbiology, Tumor and Cell Biology, and National Pandemic Center, Solna, Stockholm, Sweden
| | - Suchita Desai
- Karolinska Institutet, Department of Laboratory Medicine, Division of Pathology, Huddinge, Sweden
| | - Hasmik Jasmine Samvelyan
- School of Medicine, The Faculty of Health, Education, Medicine and Social Care, Anglia Ruskin University, Chelmsford, United Kingdom
| | - Laura Bock
- Karolinska Institutet, Department of Laboratory Medicine, Division of Pathology, Huddinge, Sweden
| | - Jianyao Wu
- Sahlgrenska Academy at The University of Gothenburg, Centre for Bone and Arthritis Research, Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, Gothenburg, Sweden
| | - Claes Ohlsson
- Sahlgrenska Academy at The University of Gothenburg, Centre for Bone and Arthritis Research, Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, Gothenburg, Sweden
| | - Anders Palmquist
- Sahlgrenska Academy at The University of Gothenburg, Department of Biomaterials, Gothenburg, Sweden
| | - Jessica J Alm
- Karolinska Institutet, Department of Microbiology, Tumor and Cell Biology, and National Pandemic Center, Solna, Stockholm, Sweden
| | - Phillip T Newton
- Karolinska Institutet, Department of Women's and Children's Health, Solna, Stockholm, Sweden; Astrid Lindgren Children's Hospital, Stockholm, Sweden
| | - Göran Andersson
- Karolinska Institutet, Department of Laboratory Medicine, Division of Pathology, Huddinge, Sweden
| | - Sara H Windahl
- Karolinska Institutet, Department of Laboratory Medicine, Division of Pathology, Huddinge, Sweden.
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Ruiz-Lozano R, Calvo-Gallego JL, Pivonka P, McDonald MM, Martínez-Reina J. An in silico approach to elucidate the pathways leading to primary osteoporosis: age-related vs. postmenopausal. Biomech Model Mechanobiol 2024; 23:1393-1409. [PMID: 38700787 DOI: 10.1007/s10237-024-01846-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 03/29/2024] [Indexed: 08/24/2024]
Abstract
Numerical models of bone remodelling have traditionally been used to perform in silico tests of bone loss in postmenopausal women and also to simulate the response to different drug treatments. These models simulate the menopausal oestrogen decline by altering certain signalling pathways. However, they do not consider the simultaneous effect that ageing can have on cell function and bone remodelling, and thus on bone loss. Considering ageing and oestrogen decline together is important for designing osteoporosis treatments that can selectively counteract one or the other disease mechanism. A previously developed bone cell population model was adapted to consider the effect of ageing through: (1) the decrease of TGF- β contained in the bone matrix and (2) an increased production of sclerostin by non-skeletal cells. Oestrogen deficiency is simulated in three different ways: (a) an increase in RANKL expression, (b) a decrease in OPG production, and (c) an increase in the responsiveness of osteoclasts to RANKL. The effect of ageing was validated using the cross-sectional study of (Riggs et al. in J Bone Miner Res 19: 1945-1954, 2004) on BMD of trabecular bone of the vertebral body of men. The joint effect of ageing and oestrogen deficiency was validated using these same clinical results but in women. In ageing, the effect of the increasing production of sclerostin is more important than the decrease of TGF- β , while the three mechanisms used to simulate the effect of oestrogen deficiency produce almost identical responses. The results show that an early menopause leads to a lower average density in the fifth decade, but after the sixth decade the average density is independent of the age at menopause. Treatment of osteoporosis with denosumab was also simulated to conclude that the drug is not very effective if started before 10 years after menopause or before age 60.
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Affiliation(s)
- Rocío Ruiz-Lozano
- Departmento de Ingeniería Mecánica y Fabricación, Universidad de Sevilla, 41092, Seville, Spain
| | - José Luis Calvo-Gallego
- Departmento de Ingeniería Mecánica y Fabricación, Universidad de Sevilla, 41092, Seville, Spain
| | - Peter Pivonka
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, QLD, 4000, Australia
| | - Michelle M McDonald
- Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Javier Martínez-Reina
- Departmento de Ingeniería Mecánica y Fabricación, Universidad de Sevilla, 41092, Seville, Spain.
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Bobba R, Kalra P, Dharmalingam M. Study of Effects of Gender-Affirming Hormone Therapy on Bone Mineral Density in Individuals with Gender Dysphoria. Indian J Endocrinol Metab 2023; 27:486-491. [PMID: 38371188 PMCID: PMC10871006 DOI: 10.4103/ijem.ijem_265_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Accepted: 09/24/2023] [Indexed: 02/20/2024] Open
Abstract
Introduction Gender affirming hormone therapy (GAHT) is the mainstay treatment in transitioning individuals and has positive physical and psychological effects. Among the things to monitor in transgender patients on long-term hormones, bone health is an essential consideration. As the calcium intake in the Indian population is less, and many gender-incongruent individuals may not take adequate calcium in their diet, we needed data on the bone health of Indians with gender dysphoria as the information available globally may not apply to our population. Materials and Methods The study was performed to assess bone mineral density in individuals with gender dysphoria who were on gender-affirming hormonal therapy for at least 6 months. It was a hospital-based cross-sectional study of bone mineral density measured at two sites - hip and spine in individuals with gender dysphoria on GAHT for at least six months. Results A total of 30 individuals were included in this study. The mean age of individuals with Gender dysphoria was found to be 28.17 ± 6.15 years, and the age range was 19-42 years. Out of the 30 individuals, 14 were transgender males, and the remaining 16 were transgender females. Bone mineral density at the hip and spine in transgender males was 1.047 ± 0.124 g/cm2 and 1.065 ± 0.115 g/cm2, which was better compared to transgender females in whom the bone mineral density at hip and spine was 0.899 ± 0.873 g/cm2 and 0.854 ± 0.099 g/cm2 (P = 0.001 for hip; P = 0.000 for spine). The Z score at hip and spine were better in transgender males as compared to transgender females (P < 0.001 for hip; P < 0.001 for spine) when compared to genetic sex and at the spine (P = 0.001) when compared to affirmed sex. In this study, we observed that the transgender females who underwent orchidectomy had a lower mean Z score at spine compared to individuals who did not undergo the procedure. Conclusions The current study results indicate that GAHT does have positive effects on bone health in transmen.
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Affiliation(s)
- Rakesh Bobba
- Department of Endocrinology, M S Ramaiah Medical College, Bengaluru, Karnataka, India
| | - Pramila Kalra
- Department of Endocrinology, M S Ramaiah Medical College, Bengaluru, Karnataka, India
| | - Mala Dharmalingam
- Department of Endocrinology, M S Ramaiah Medical College, Bengaluru, Karnataka, India
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Testosterone Deficiency as One of the Major Endocrine Disorders in Chronic Kidney Disease. Nutrients 2022; 14:nu14163438. [PMID: 36014945 PMCID: PMC9415930 DOI: 10.3390/nu14163438] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 08/11/2022] [Accepted: 08/19/2022] [Indexed: 11/28/2022] Open
Abstract
Reduced testosterone concentration is nowadays thought to be one of the main endocrine disorders in chronic kidney disease (CKD). It is caused by the dysfunction of the hypothalamic-pituitary-gonadal axis. The role of testosterone is multifactorial. Testosterone is responsible not only for reproductive processes, but it is a hormone which increases bone and muscle mass, improves lipid profile, insulin sensitivity, erythropoiesis, reduces blood pressure, and ameliorates mood and perception. The implications of hypogonadism in CKD are infertility and loss of libido, reduction of muscle mass and strength, disorders in bone mineralization, the development of sarcopenia and protein energy wasting (PEW), progression of atherosclerosis, increased visceral adiposity, insulin resistance, and anaemia. Reduced testosterone serum concentrations in CKD are associated with increased mortality rate. Testosterone supplementation improves sexual functions, reduces the level of inflammatory markers and blood pressure, stimulates muscle protein synthesis, improves insulin sensitivity and lipid profile, and increases muscle mass, bone mineral density, and haemoglobin concentration. It positively affects mood and well-being. The modes of testosterone supplementation are intramuscular injections, subcutaneous pellets, and percutaneous methods—patches and gels. Successful kidney transplantation may improve gonadal function and testosterone production, however, half of men with low testosterone concentrations before kidney transplantation do not restore hormonal function.
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Wang X, Jiang J, Guan W, Yu W, Xu T, Li M, Zhang J. The risk factors for developing clustered vertebral compression fractures: a single center study. Endocr Pract 2021; 28:243-249. [PMID: 34952220 DOI: 10.1016/j.eprac.2021.12.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 11/14/2021] [Accepted: 12/15/2021] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Vertebral compression fractures (VCFs) are common among elderly individuals, but clustered VCFs (C-VCFs) are rare and more severe. The risk factors for C-VCFs remain unclear. Thus, we investigated the clinical characteristics of C-VCFs to identify the imminent fracture risk and to improve the treatment for such patients. METHODS We reviewed records of VCF patients at a single medical center between January 2011 and September 2020. Patients who had four or more VCFs within one year were categorized into the C-VCF group, and the remaining patients were paired into the control group at a ratio of 2:1. We collected demographic, clinical, laboratory, and radiological information regarding these patients. Univariate analyses, stratified analyses, and multivariate logistic regression were performed to identify the risk factors for C-VCFs. RESULTS A total of 156 patients were enrolled, of whom 52 were C-VCF patients. C-VCF patients had more severe fractures and pain, with fractures occurring at uncommon sites of the spine. The independent risk factors for C-VCFs included glucocorticoid treatment (P<0.001, HR: 12.7), recent fracture history (P=0.021, HR: 5.5), and lower trabecular bone score (TBS, P=0.044, HR: 1.6). TBS and bone mineral density had greater predictive values in patients without glucocorticoid treatment (P<0.001). Sex, age, and bone turnover biomarkers were not independent risk factors for C-VCFs. CONCLUSION C-VCFs are rare adverse consequences of severe osteoporosis, for which glucocorticoid treatment, recent fracture history, and lower TBS are unique risk factors that are valuable for the early identification and prevention of C-VCFs.
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Affiliation(s)
- Xianze Wang
- Department of Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Science & Peking Union Medical College, Beijing, China
| | - Jialin Jiang
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Science & Peking Union Medical College, Beijing, China
| | - Wenmin Guan
- Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Wei Yu
- Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Tao Xu
- Department of Epidemiology and Biostatistics, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & School of Basic Medicine, Peking Union Medical College, Beijing, China
| | - Mei Li
- Department of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.
| | - Jia Zhang
- Department of Orthopedics, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.
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Formenti AM, Dalla Volta A, di Filippo L, Berruti A, Giustina A. Effects of Medical Treatment of Prostate Cancer on Bone Health. Trends Endocrinol Metab 2021; 32:135-158. [PMID: 33509658 DOI: 10.1016/j.tem.2020.12.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 12/21/2020] [Accepted: 12/21/2020] [Indexed: 01/13/2023]
Abstract
Medical treatment of prostate cancer (PC) is multidisciplinary, resulting in prolonged survival. Androgen-deprivation therapy (ADT) can have negative effects on skeletal metabolism, particularly if combined with glucocorticoids. We discuss the pathophysiology and effects of ADT and glucocorticoids on skeletal endpoints, as well as the awareness and management of bone fragility. Coadministration of glucocorticoids is necessary with abiraterone because this causes a novel acquired form of 17-hydroxylase deficiency and synergistically increases the risk of fracture by affecting bone quality. Bone antiresorptive agents [selective estrogen receptor modulators (SERMS), bisphosphonates, and denosumab] increase bone mineral density (BMD) and in some instances reduce fracture risk in PC patients on ADT. Awareness and management of bone health in PC can be improved by integrating endocrinologists into the multidisciplinary PC team.
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Affiliation(s)
- Anna Maria Formenti
- Institute of Endocrine and Metabolic Sciences, San Raffaele Vita Salute University, Istituto Di Ricovero e Cura a Carattere Scientifico (IRCCS), San Raffaele Hospital, Milan, Italy
| | - Alberto Dalla Volta
- Medical Oncology, Department of Medical and Surgical Specialties, Radiological Sciences, and Public Health, University of Brescia, Azienda Socio Sanitaria Territoriale (ASST) Spedali Civili, Brescia, Italy
| | - Luigi di Filippo
- Institute of Endocrine and Metabolic Sciences, San Raffaele Vita Salute University, Istituto Di Ricovero e Cura a Carattere Scientifico (IRCCS), San Raffaele Hospital, Milan, Italy
| | - Alfredo Berruti
- Medical Oncology, Department of Medical and Surgical Specialties, Radiological Sciences, and Public Health, University of Brescia, Azienda Socio Sanitaria Territoriale (ASST) Spedali Civili, Brescia, Italy
| | - Andrea Giustina
- Institute of Endocrine and Metabolic Sciences, San Raffaele Vita Salute University, Istituto Di Ricovero e Cura a Carattere Scientifico (IRCCS), San Raffaele Hospital, Milan, Italy.
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La Vignera S, Aversa A, Cannarella R, Condorelli RA, Duca Y, Russo GI, Calogero AE. Pharmacological treatment of lower urinary tract symptoms in benign prostatic hyperplasia: consequences on sexual function and possible endocrine effects. Expert Opin Pharmacother 2020; 22:179-189. [DOI: 10.1080/14656566.2020.1817382] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Sandro La Vignera
- Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Antonio Aversa
- Department of Experimental and Clinical Medicine, “Magna Graecia” University, Catanzaro, Italy
| | - Rossella Cannarella
- Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Rosita A. Condorelli
- Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Ylenia Duca
- Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Giorgio I. Russo
- Department of Experimental and Clinical Medicine, “Magna Graecia” University, Catanzaro, Italy
| | - Aldo E. Calogero
- Department of Surgery, Urology Section, University of Catania, Catania, Italy
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Antoniou T, Macdonald EM, Yao Z, Gomes T, Tadrous M, Ho JMW, Mamdani MM, Juurlink DN. A population-based study of the risk of osteoporosis and fracture with dutasteride and finasteride. BMC Musculoskelet Disord 2018; 19:160. [PMID: 29789004 PMCID: PMC5964967 DOI: 10.1186/s12891-018-2076-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 05/07/2018] [Indexed: 01/22/2023] Open
Abstract
Background Dutasteride is a potent inhibitor of 5-alpha reductase enzymes that reduces concentrations of dihydrotestosterone to a greater extent than finasteride. Whether this has adverse implications for bone health is unknown. We compared the risk of osteoporosis and fractures in older men treated with dutasteride or finasteride. Methods We conducted a population-based retrospective cohort study with high-dimensional propensity score matching of Ontario men aged 66 years or older who started treatment with dutasteride or finasteride between January 1, 2006 and December 31, 2012. The primary outcome was a diagnosis of osteoporosis within 2 years of treatment initiation. A secondary outcome was osteoporotic or fragility fractures. Results We studied 31,615 men treated with dutasteride and an equal number of men treated with finasteride. Dutasteride-treated patients had a lower incidence of osteoporosis than those receiving finasteride [2.2 versus 2.6 per 100 person years; hazard ratio (HR) 0.82; 95% confidence interval (CI) 0.72 to 0.93]. This effect was no longer statistically significant following adjustment for specialty of prescribing physician (HR 0.90; 95% CI 0.78 to 1.02)]. There was no differential risk of fractures with dutasteride (HR 1.04; 95% 0.86 to 1.25). Conclusions Despite differential effects on 5-alpha reductase, dutasteride is not associated with an increased risk of osteoporosis or fractures in older men relative to finasteride. These findings suggest that dutasteride does not adversely affect bone health. Electronic supplementary material The online version of this article (10.1186/s12891-018-2076-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Tony Antoniou
- Department of Family and Community Medicine, St. Michael's Hospital, 410 Sherbourne Street, 4th Floor, Toronto, ON, M4X 1K2, Canada. .,Li Ka Shing Knowledge Institute, St. Michael's Hospital, 410 Sherbourne Street, 4th Floor, Toronto, ON, M4X 1K2, Canada. .,University of Toronto, 410 Sherbourne Street, 4th Floor, Toronto, ON, M4X 1K2, Canada. .,Institute for Clinical Evaluative Sciences, 410 Sherbourne Street, 4th Floor, Toronto, ON, M4X 1K2, Canada.
| | - Erin M Macdonald
- Institute for Clinical Evaluative Sciences, 410 Sherbourne Street, 4th Floor, Toronto, ON, M4X 1K2, Canada
| | - Zhan Yao
- Institute for Clinical Evaluative Sciences, 410 Sherbourne Street, 4th Floor, Toronto, ON, M4X 1K2, Canada
| | - Tara Gomes
- Li Ka Shing Knowledge Institute, St. Michael's Hospital, 410 Sherbourne Street, 4th Floor, Toronto, ON, M4X 1K2, Canada.,University of Toronto, 410 Sherbourne Street, 4th Floor, Toronto, ON, M4X 1K2, Canada.,Institute for Clinical Evaluative Sciences, 410 Sherbourne Street, 4th Floor, Toronto, ON, M4X 1K2, Canada
| | - Mina Tadrous
- University of Toronto, 410 Sherbourne Street, 4th Floor, Toronto, ON, M4X 1K2, Canada.,Institute for Clinical Evaluative Sciences, 410 Sherbourne Street, 4th Floor, Toronto, ON, M4X 1K2, Canada.,Applied Health Research Centre, St. Michael's Hospital, Toronto, ON, Canada
| | - Joanne M-W Ho
- Department of Medicine, McMaster University, Hamilton, ON, Canada.,Schlegel Research Institute for Aging, Waterloo, ON, Canada
| | - Muhammad M Mamdani
- Li Ka Shing Knowledge Institute, St. Michael's Hospital, 410 Sherbourne Street, 4th Floor, Toronto, ON, M4X 1K2, Canada.,University of Toronto, 410 Sherbourne Street, 4th Floor, Toronto, ON, M4X 1K2, Canada.,Institute for Clinical Evaluative Sciences, 410 Sherbourne Street, 4th Floor, Toronto, ON, M4X 1K2, Canada.,Applied Health Research Centre, St. Michael's Hospital, Toronto, ON, Canada.,King Saud University, Riyadh, Saudi Arabia
| | - David N Juurlink
- University of Toronto, 410 Sherbourne Street, 4th Floor, Toronto, ON, M4X 1K2, Canada.,Institute for Clinical Evaluative Sciences, 410 Sherbourne Street, 4th Floor, Toronto, ON, M4X 1K2, Canada.,Sunnybrook Research Institute, Toronto, ON, Canada
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Almeida M, Laurent MR, Dubois V, Claessens F, O'Brien CA, Bouillon R, Vanderschueren D, Manolagas SC. Estrogens and Androgens in Skeletal Physiology and Pathophysiology. Physiol Rev 2017; 97:135-187. [PMID: 27807202 PMCID: PMC5539371 DOI: 10.1152/physrev.00033.2015] [Citation(s) in RCA: 466] [Impact Index Per Article: 66.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Estrogens and androgens influence the growth and maintenance of the mammalian skeleton and are responsible for its sexual dimorphism. Estrogen deficiency at menopause or loss of both estrogens and androgens in elderly men contribute to the development of osteoporosis, one of the most common and impactful metabolic diseases of old age. In the last 20 years, basic and clinical research advances, genetic insights from humans and rodents, and newer imaging technologies have changed considerably the landscape of our understanding of bone biology as well as the relationship between sex steroids and the physiology and pathophysiology of bone metabolism. Together with the appreciation of the side effects of estrogen-related therapies on breast cancer and cardiovascular diseases, these advances have also drastically altered the treatment of osteoporosis. In this article, we provide a comprehensive review of the molecular and cellular mechanisms of action of estrogens and androgens on bone, their influences on skeletal homeostasis during growth and adulthood, the pathogenetic mechanisms of the adverse effects of their deficiency on the female and male skeleton, as well as the role of natural and synthetic estrogenic or androgenic compounds in the pharmacotherapy of osteoporosis. We highlight latest advances on the crosstalk between hormonal and mechanical signals, the relevance of the antioxidant properties of estrogens and androgens, the difference of their cellular targets in different bone envelopes, the role of estrogen deficiency in male osteoporosis, and the contribution of estrogen or androgen deficiency to the monomorphic effects of aging on skeletal involution.
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Affiliation(s)
- Maria Almeida
- Division of Endocrinology and Metabolism, Center for Osteoporosis and Metabolic Bone Diseases, University of Arkansas for Medical Sciences and the Central Arkansas Veterans Healthcare System, Little Rock, Arkansas; Departments of Cellular and Molecular Medicine and Clinical and Experimental Medicine, KU Leuven, Leuven, Belgium; Center for Metabolic Bone Diseases, University Hospitals Leuven, Leuven, Belgium; and Institut National de la Santé et de la Recherche Médicale UMR1011, University of Lille and Institut Pasteur de Lille, Lille, France
| | - Michaël R Laurent
- Division of Endocrinology and Metabolism, Center for Osteoporosis and Metabolic Bone Diseases, University of Arkansas for Medical Sciences and the Central Arkansas Veterans Healthcare System, Little Rock, Arkansas; Departments of Cellular and Molecular Medicine and Clinical and Experimental Medicine, KU Leuven, Leuven, Belgium; Center for Metabolic Bone Diseases, University Hospitals Leuven, Leuven, Belgium; and Institut National de la Santé et de la Recherche Médicale UMR1011, University of Lille and Institut Pasteur de Lille, Lille, France
| | - Vanessa Dubois
- Division of Endocrinology and Metabolism, Center for Osteoporosis and Metabolic Bone Diseases, University of Arkansas for Medical Sciences and the Central Arkansas Veterans Healthcare System, Little Rock, Arkansas; Departments of Cellular and Molecular Medicine and Clinical and Experimental Medicine, KU Leuven, Leuven, Belgium; Center for Metabolic Bone Diseases, University Hospitals Leuven, Leuven, Belgium; and Institut National de la Santé et de la Recherche Médicale UMR1011, University of Lille and Institut Pasteur de Lille, Lille, France
| | - Frank Claessens
- Division of Endocrinology and Metabolism, Center for Osteoporosis and Metabolic Bone Diseases, University of Arkansas for Medical Sciences and the Central Arkansas Veterans Healthcare System, Little Rock, Arkansas; Departments of Cellular and Molecular Medicine and Clinical and Experimental Medicine, KU Leuven, Leuven, Belgium; Center for Metabolic Bone Diseases, University Hospitals Leuven, Leuven, Belgium; and Institut National de la Santé et de la Recherche Médicale UMR1011, University of Lille and Institut Pasteur de Lille, Lille, France
| | - Charles A O'Brien
- Division of Endocrinology and Metabolism, Center for Osteoporosis and Metabolic Bone Diseases, University of Arkansas for Medical Sciences and the Central Arkansas Veterans Healthcare System, Little Rock, Arkansas; Departments of Cellular and Molecular Medicine and Clinical and Experimental Medicine, KU Leuven, Leuven, Belgium; Center for Metabolic Bone Diseases, University Hospitals Leuven, Leuven, Belgium; and Institut National de la Santé et de la Recherche Médicale UMR1011, University of Lille and Institut Pasteur de Lille, Lille, France
| | - Roger Bouillon
- Division of Endocrinology and Metabolism, Center for Osteoporosis and Metabolic Bone Diseases, University of Arkansas for Medical Sciences and the Central Arkansas Veterans Healthcare System, Little Rock, Arkansas; Departments of Cellular and Molecular Medicine and Clinical and Experimental Medicine, KU Leuven, Leuven, Belgium; Center for Metabolic Bone Diseases, University Hospitals Leuven, Leuven, Belgium; and Institut National de la Santé et de la Recherche Médicale UMR1011, University of Lille and Institut Pasteur de Lille, Lille, France
| | - Dirk Vanderschueren
- Division of Endocrinology and Metabolism, Center for Osteoporosis and Metabolic Bone Diseases, University of Arkansas for Medical Sciences and the Central Arkansas Veterans Healthcare System, Little Rock, Arkansas; Departments of Cellular and Molecular Medicine and Clinical and Experimental Medicine, KU Leuven, Leuven, Belgium; Center for Metabolic Bone Diseases, University Hospitals Leuven, Leuven, Belgium; and Institut National de la Santé et de la Recherche Médicale UMR1011, University of Lille and Institut Pasteur de Lille, Lille, France
| | - Stavros C Manolagas
- Division of Endocrinology and Metabolism, Center for Osteoporosis and Metabolic Bone Diseases, University of Arkansas for Medical Sciences and the Central Arkansas Veterans Healthcare System, Little Rock, Arkansas; Departments of Cellular and Molecular Medicine and Clinical and Experimental Medicine, KU Leuven, Leuven, Belgium; Center for Metabolic Bone Diseases, University Hospitals Leuven, Leuven, Belgium; and Institut National de la Santé et de la Recherche Médicale UMR1011, University of Lille and Institut Pasteur de Lille, Lille, France
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10
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Abstract
Osteoporosis is a condition causing significant morbidity and mortality in the elderly population worldwide. Age-related testosterone deficiency is the most important factor of bone loss in elderly men. Androgen can influence bone health by binding to androgen receptors directly or to estrogen receptors (ERs) indirectly via aromatization to estrogen. This review summarized the direct and indirect effects of androgens on bone derived from in vitro, in vivo, and human studies. Cellular studies showed that androgen stimulated the proliferation of preosteoblasts and differentiation of osteoblasts. The converted estrogen suppressed osteoclast formation and resorption activity by blocking the receptor activator of nuclear factor k-B ligand pathway. In animal studies, activation of androgen and ERα, but not ERβ, was shown to be important in acquisition and maintenance of bone mass. Human epidemiological studies demonstrated a significant relationship between estrogen and testosterone in bone mineral density and fracture risk, but the relative significance between the two remained debatable. Human experimental studies showed that estrogen was needed in suppressing bone resorption, but both androgen and estrogen were indispensable for bone formation. As a conclusion, maintaining optimal level of androgen is essential in preventing osteoporosis and its complications in elderly men.
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Affiliation(s)
- Nur-Vaizura Mohamad
- Department of Pharmacology, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lampur, Malaysia
| | - Ima-Nirwana Soelaiman
- Department of Pharmacology, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lampur, Malaysia
| | - Kok-Yong Chin
- Department of Pharmacology, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lampur, Malaysia
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Potikanond S, Rattanachote P, Pintana H, Suntornsaratoon P, Charoenphandhu N, Chattipakorn N, Chattipakorn S. Obesity does not aggravate osteoporosis or osteoblastic insulin resistance in orchiectomized rats. J Endocrinol 2016; 228:85-95. [PMID: 26675491 DOI: 10.1530/joe-15-0333] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/13/2015] [Indexed: 01/03/2023]
Abstract
The present study aimed to test the hypothesis that testosterone deprivation impairs osteoblastic insulin signaling, decreases osteoblast survival, reduces bone density, and that obesity aggravates those deleterious effects in testosterone-deprived rats. Twenty four male Wistar rats underwent either a bilateral orchiectomy (O, n=12) or a sham operation (S, n=12). Then the rats in each group were further divided into two subgroups fed with either a normal diet (ND) or a high-fat diet (HF) for 12 weeks. At the end of the protocol, blood samples were collected to determine metabolic parameters and osteocalcin ratios. The tibiae were collected to determine bone mass using microcomputed tomography and for osteoblast isolation. The results showed that rats fed with HF (sham-operated HF-fed rats (HFS) and ORX HF-fed rats (HFO)) developed peripheral insulin resistance and had decreased trabecular bone density. In ND-fed rats, only the ORX ND-fed rats (NDO) group had decreased trabecular bone density. In addition, osteoblastic insulin resistance, as indicated by a decrease in tyrosine phosphorylation of the insulin receptor and Akt, were observed in all groups except the sham-operated ND-fed rats (NDS) rats. Those groups, again with the exception of the NDS rats, also had decreased osteoblastic survival. No differences in the levels of osteoblastic insulin resistance and osteoblastic survival were found among the NDO, HFS, and HFO groups. These findings suggest that either testosterone deprivation or obesity alone can impair osteoblastic insulin signaling and decrease osteoblastic survival leading to the development of osteoporosis. However, obesity does not aggravate those deleterious effects in the bone of testosterone-deprived rats.
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Affiliation(s)
- Saranyapin Potikanond
- Department of PharmacologyFaculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Pinyada Rattanachote
- Neurophysiology Unit, Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Hiranya Pintana
- Center of Calcium and Bone Research (COCAB)Faculty of Science, Mahidol University, Bangkok, Thailand
| | | | - Narattaphol Charoenphandhu
- Cardiac Electrophysiology Unit Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Nipon Chattipakorn
- Center of Excellence in Cardiac Electrophysiology ResearchChiang Mai University, Chiang Mai, Thailand
| | - Siriporn Chattipakorn
- Department of Oral Biology and Diagnostic SciencesFaculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand
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12
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Greco EA, Lenzi A, Migliaccio S. The pathophysiological basis of bone tissue alterations associated with eating disorders. Horm Mol Biol Clin Investig 2016; 28:121-132. [DOI: 10.1515/hmbci-2016-0006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 02/09/2016] [Indexed: 12/13/2022]
Abstract
AbstractAnorexia nervosa (AN) and obesity are two major eating disorders present nowadays in Western countries. They are both characterized by striking body composition variations and hormonal alterations, which impact on skeletal metabolism, inducing bone tissue modifications and, thus, often cause an increased risk for fractures. AN and obesity are characterized by a severe reduction in fat mass and a high expression of it, respectively, and in both conditions hormones secreted or modulated by body fat content are important determinants of low bone density, impaired bone structure and reduced bone strength. In addition, in both AN and obesity, increased marrow adiposity, which correlates with low bone density, has been observed. This review will discuss the pathophysiological basis of bone alterations associated with AN and obesity, conditions of extreme energy deficiency and excess, respectively.
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13
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Muriel J, Pérez-Rodríguez L, Puerta M, Gil D. Diverse dose-response effects of yolk androgens on embryo development and nestling growth in a wild passerine. ACTA ACUST UNITED AC 2015; 218:2241-9. [PMID: 25987739 DOI: 10.1242/jeb.118257] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 05/06/2015] [Indexed: 11/20/2022]
Abstract
Avian egg yolks contain various amounts of maternally derived androgens that can modify offspring phenotype and adjust their development to the post-hatching environment. Seemingly adaptive variation in yolk androgen levels with respect to breeding density conditions or male attractiveness has been found in numerous studies. One important consideration that has been overlooked in previous research is the likely non-linear nature of hormone effects. To examine possible complex dose-response effects of maternal androgens on chick development, we experimentally administered three different androgen doses of the naturally occurring mixture of yolk testosterone and androstenedione to spotless starling eggs (Sturnus unicolor). We found that yolk androgens induce a non-linear dose-response pattern in several traits. Androgens had a stimulatory effect on hatchling body mass and nestling skeletal growth, but maximum values were found at intermediate doses, whereas our highest dose resulted in a decrease. However, the opposite U-shaped effect was found on nestling body mass. We also detected linear negative and positive effects on embryonic development period and nestling gape width, respectively. Our results suggest differential tissue responsiveness to yolk androgens, which may result in compromises in maternal allocation to produce adapted phenotypes. Because of the non-linear dose-response pattern, future investigations should carefully consider a wide range of concentrations, as the balance of costs and benefits may strongly differ depending on concentration.
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Affiliation(s)
- Jaime Muriel
- Departamento de Ecología Evolutiva, Museo Nacional de Ciencias Naturales (MNCN-CSIC), José Gutiérrez Abascal 2, Madrid E-28006, Spain
| | - Lorenzo Pérez-Rodríguez
- Departamento de Ecología Evolutiva, Museo Nacional de Ciencias Naturales (MNCN-CSIC), José Gutiérrez Abascal 2, Madrid E-28006, Spain Departamento de Ecología Evolutiva, Estación Biológica de Doñana (EBD-CSIC), Avda. Américo Vespucio, s/n, Isla de la Cartuja, Sevilla 41092, Spain
| | - Marisa Puerta
- Departamento de Fisiología Animal II, Facultad de Ciencias Biológicas, Universidad Complutense, José Antonio Novais, 2 Ciudad Universitaria, Madrid 28040, Spain
| | - Diego Gil
- Departamento de Ecología Evolutiva, Museo Nacional de Ciencias Naturales (MNCN-CSIC), José Gutiérrez Abascal 2, Madrid E-28006, Spain
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14
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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: 185] [Impact Index Per Article: 18.5] [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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Abstract
Anorexia nervosa is a serious psychiatric disorder accompanied by high morbidity and mortality. It is characterized by emaciation due to self-starvation and displays a unique hormonal profile. Alterations in gonadal axis, growth hormone resistance with low insulin-like growth factor I levels, hypercortisolemia and low triiodothyronine levels are almost universally present and constitute an adaptive response to malnutrition. Bone metabolism is likewise affected resulting in low bone mineral density, reduced bone accrual and increased fracture risk. Skeletal deficits often persist even after recovery from the disease with serious implications for future skeletal health. The pathogenetic mechanisms underlying bone disease are quite complicated and treatment is a particularly challenging task.
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Affiliation(s)
- Anastasia D Dede
- Department of Endocrinology and Metabolism, Hippokrateion General Hospital, Athens, Greece
| | | | - Symeon Tournis
- Laboratory for Research of Musculoskeletal System "Theodoros Garofalidis", University of Athens, KAT Hospital; Athens, Greece
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16
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Inaba T, Kobayashi T, Tsutsui TW, Ogawa M, Uchida M, Tsutsui T. Expression status of mRNA for sex hormone receptors in human dental pulp cells and the response to sex hormones in the cells. Arch Oral Biol 2013; 58:943-50. [DOI: 10.1016/j.archoralbio.2013.02.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 12/11/2012] [Accepted: 02/02/2013] [Indexed: 01/09/2023]
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17
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Montalvo C, Villar AV, Merino D, García R, Ares M, Llano M, Cobo M, Hurlé MA, Nistal JF. Androgens contribute to sex differences in myocardial remodeling under pressure overload by a mechanism involving TGF-β. PLoS One 2012; 7:e35635. [PMID: 22558184 PMCID: PMC3338422 DOI: 10.1371/journal.pone.0035635] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2011] [Accepted: 03/19/2012] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND In clinical studies, myocardial remodeling in aortic valve stenosis appears to be more favorable in women than in men, even after menopause. In the present study, we assessed whether circulating androgens contribute to a less favorable myocardial remodeling under pressure overload in males. We examined sex-related differences in one-year-old male and female mice. Whereas male mice at this age exhibited circulating androgen levels within the normal range for young adults, the circulating estrogens in females were reduced. The contribution of gonadal androgens to cardiac remodeling was analyzed in a group of same-age castrated mice. METHODOLOGY/PRINCIPAL FINDINGS Animals were subjected to transverse aortic constriction (TAC). Echocardiography was performed 2 weeks after TAC and myocardial mRNA levels of TGF-βs, Smads 2 and 3, collagens, fibronectin, β-myosin heavy chain and α-myosin heavy chain were determined by q-PCR. Protein detection of p-SMAD2/3 was performed by Western Blot. Histological staining of fibrosis was performed with picrosirius red and Masson's trichrome. Compared with females, males developed more severe tissue fibrosis, LV dilation and hemodynamic dysfunction. TAC-males showed higher myocardial expression levels of TGF-βs and the treatment with a neutralizing antibody to TGF-β prevented myocardial fibrosis development. Orchiectomy diminished TAC-induced up-regulation of TGF-βs and TGF-β target genes, and it also reduced fibrosis and hemodynamic dysfunction. The capability of androgens to induce TGF-β expression was confirmed in NIH-3T3 fibroblasts and H9C2 cardiomyocytes exposed to dihydrotestosterone. CONCLUSIONS/SIGNIFICANCE Our results indicate that circulating androgens are responsible for the detrimental effects in the myocardium of older male mice subjected to pressure overload through a mechanism involving TGF-βs.
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Affiliation(s)
- Cecilia Montalvo
- Departamento de Fisiología y Farmacología, Facultad de Medicina, Universidad de Cantabria, Santander, Spain
- Instituto de Formación e Investigación Marqués de Valdecilla (IFIMAV), Santander, Spain
| | - Ana V. Villar
- Departamento de Fisiología y Farmacología, Facultad de Medicina, Universidad de Cantabria, Santander, Spain
- Instituto de Formación e Investigación Marqués de Valdecilla (IFIMAV), Santander, Spain
| | - David Merino
- Departamento de Fisiología y Farmacología, Facultad de Medicina, Universidad de Cantabria, Santander, Spain
- Instituto de Formación e Investigación Marqués de Valdecilla (IFIMAV), Santander, Spain
| | - Raquel García
- Servicio de Cirugía Cardiovascular, Hospital Universitario Marqués de Valdecilla, Santander, Spain
- Instituto de Formación e Investigación Marqués de Valdecilla (IFIMAV), Santander, Spain
| | - Miguel Ares
- Hospital Comarcal de Laredo, Cantabria, Spain
- Instituto de Formación e Investigación Marqués de Valdecilla (IFIMAV), Santander, Spain
| | - Miguel Llano
- Servicio de Cardiología, Hospital Universitario Marqués de Valdecilla, Santander, Spain
- Instituto de Formación e Investigación Marqués de Valdecilla (IFIMAV), Santander, Spain
| | - Manuel Cobo
- Servicio de Cardiología, Hospital Universitario Marqués de Valdecilla, Santander, Spain
- Instituto de Formación e Investigación Marqués de Valdecilla (IFIMAV), Santander, Spain
| | - María A. Hurlé
- Departamento de Fisiología y Farmacología, Facultad de Medicina, Universidad de Cantabria, Santander, Spain
- Instituto de Formación e Investigación Marqués de Valdecilla (IFIMAV), Santander, Spain
- * E-mail:
| | - J. Francisco Nistal
- Servicio de Cirugía Cardiovascular, Hospital Universitario Marqués de Valdecilla, Santander, Spain
- Instituto de Formación e Investigación Marqués de Valdecilla (IFIMAV), Santander, Spain
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18
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Chen P, Wang SJ, Wang HB, Ren P, Wang XQ, Liu WG, Gu WL, Li DQ, Zhang TG, Zhou CJ. The distribution of IGF2 and IMP3 in osteosarcoma and its relationship with angiogenesis. J Mol Histol 2011; 43:63-70. [DOI: 10.1007/s10735-011-9370-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Accepted: 10/16/2011] [Indexed: 01/16/2023]
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Abstract
The sex steroid hormones, androgens and estrogens, via their respective nuclear receptors, regulate bone mineral density in humans and mice. Very little is known about the direct targets of the androgen and estrogen receptors in bone cells. First, models of hormone and receptor deficiency in mouse and human bone are discussed. This review then focuses on the direct targets of the receptors in osteoblasts and osteoclasts. A direct target of a NR is defined here as a gene that is regulated by NR binding to the DNA (either through DNA binding or association with a DNA binding protein) at an enhancer or promoter of that gene. The experimental evidence that illustrates androgen and estrogen gene regulation in osteoblasts and osteoclasts will be summarized and compared with the phenotype of the hormones in vivo.
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Affiliation(s)
- Susan A Krum
- Department of Orthopaedic Surgery, UCLA Orthopaedic Hospital, David Geffen School of Medicine at UCLA, Los Angeles, California 90095, USA.
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20
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Kasperk C. Das Osteoporoserisiko der antiandrogenen Therapie des Mannes. FORENSISCHE PSYCHIATRIE PSYCHOLOGIE KRIMINOLOGIE 2010. [DOI: 10.1007/s11757-010-0053-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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21
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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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22
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Ilangovan R, Sittadjody S, Balaganesh M, Sivakumar R, Ravi Sankar B, Balasubramanian K, Srinivasan S, Subramanian C, Thompson DM, Queimado L, Srinivasan N. Dihydrotestosterone is a determinant of calcaneal bone mineral density in men. J Steroid Biochem Mol Biol 2009; 117:132-8. [PMID: 19732831 DOI: 10.1016/j.jsbmb.2009.08.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2009] [Revised: 08/24/2009] [Accepted: 08/25/2009] [Indexed: 12/14/2022]
Abstract
Male osteoporosis is an increasingly important health problem worldwide. Though androgen deficiency leads to bone loss in men, information on the relative contribution of aromatizable and non-aromatizable androgens in maintaining bone mineral density (BMD) and the mechanisms involved are unclear. This cross-sectional study was designed to explore the same. Hundred osteoporotic men with age matched normal were studied for serum levels of sex steroids, PTH, IGF system components, cytokines and bone turnover markers. Our findings show that serum DHT, IGF-I, IGF-II and IGFBP-3 levels were significantly decreased while IL-1beta and bone turnover markers were significantly increased in osteoporotic men compared to normal. Pearson correlation analysis revealed that serum DHT, IGF-I, IGF-II and IGFBP-3 levels were positively and strongly correlated with BMD, while serum IL-1beta levels were negatively correlated with BMD. Serum PTH, testosterone, estradiol, IGFBP-4, TNF-alpha, IL-4 and IFN-gamma levels were similar between the two groups. We observed that DHT levels significantly declined with age. However, the significant difference in DHT between the osteoporotic and normal groups is the same regardless of age. A multiple regression model adjusted for age demonstrated that DHT/BMD association is fairly stronger among those with osteoporosis than the normal. Our findings for the first time point out that DHT is an important determinant of BMD in men. Most importantly, the strong positive correlation of serum DHT with BMD offers new perspectives in understanding the role of non-aromatizable androgen in regulating bone metabolism in men, and might serve as a potential clinical marker in the diagnosis of male osteoporosis.
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Affiliation(s)
- Ramachandran Ilangovan
- Department of Endocrinology, Dr. ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Tamil Nadu, India
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23
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Abstract
Testosterone is the major gonadal sex steroid produced by the testes in men. Testosterone is also produced in smaller amounts by the ovaries in women. The adrenal glands produce the weaker androgens dehydroepiandrosterone, dehydroepiandrosterone sulfate, and androstenedione. These androgens collectively affect skeletal homeostasis throughout life in both men and women, particularly at puberty and during adult life. Because testosterone can be metabolized to estradiol by the aromatase enzyme, there has been controversy as to which gonadal sex steroid has the greater skeletal effect. The current evidence suggests that estradiol plays a greater role in maintenance of skeletal health than testosterone, but that androgens also have direct beneficial effects on bone. Supraphysiological levels of testosterone likely have similar effects on bone as lower levels via direct interaction with androgen receptors, as well as effects mediated by estrogen receptors after aromatization to estradiol. Whether high doses of synthetic, non-aromatizable androgens may, in fact, be detrimental to bone due to suppression of endogenous testosterone (and estrogen) levels is a potential concern that warrants further study.
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Affiliation(s)
- Bart L Clarke
- Mayo Clinic W18-A, 200 1st Street SW, Rochester, MN 55905, USA.
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24
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Bergemann N, Parzer P, Mundt C, Auler B. High bone turnover but normal bone mineral density in women suffering from schizophrenia. Psychol Med 2008; 38:1195-1201. [PMID: 18366816 DOI: 10.1017/s003329170800319x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND A potential association between schizophrenia and osteoporosis or osteopenia has recently been reported. Various factors affect bone mineral density (BMD) such as polydipsia, nicotine, alcohol abuse, lack of physical activity, an unbalanced diet, a lack of ultraviolet exposure and/or vitamin D. In addition, decreased BMD in women with schizophrenia has been attributed to drug-induced hyperprolactinaemia and/or secondary hypogonadism. This study was undertaken because empirical evidence from larger patient cohorts is limited and the data are still controversial. METHOD Seventy-two premenopausal, regularly menstruating women suffering from schizophrenia and 71 age- and sex-matched healthy controls were included in the study. Biochemical markers of bone turnover (serum osteocalcin, urinary pyridinium crosslinks), parathyroid hormone and 25-hydroxyvitamin D were measured. BMD at the femoral neck and lumbar spine was determined by dual-energy X-ray absorptiometry in a subgroup of 59 patients. In addition, 17beta-oestradiol, prolactin, testosterone, gonadotrophins and dehydroepiandrosterone sulfate were measured. RESULTS Compared with healthy controls, both markers of formation and resorption were increased in women with schizophrenia. However, in the subgroup of 59 patients, BMD was within the normal range. In women suffering from schizophrenia, testosterone levels were higher than in controls, and serum oestradiol levels were lower compared with the normal range. CONCLUSION Despite significantly increased bone turnover, we conclude that premenopausal and regularly menstruating women suffering from schizophrenia have normal spine and hip BMD. This may be due to the opposite effects of the various parameters influencing bone metabolism, especially of the gonadal hormones, and due to an intact coupling mechanism.
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Affiliation(s)
- N Bergemann
- Department of General Psychiatry, University of Heidelberg, Heidelberg, Germany.
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25
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Navara KJ, Mendonça MT. Yolk androgens as pleiotropic mediators of physiological processes: A mechanistic review. Comp Biochem Physiol A Mol Integr Physiol 2008; 150:378-86. [DOI: 10.1016/j.cbpa.2008.05.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2007] [Revised: 05/01/2008] [Accepted: 05/02/2008] [Indexed: 01/01/2023]
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Abstract
Aromatase is a key enzyme of intratumoral production of estrogen in breast cancers. Aromatase inhibitors are commonly used as hormone therapy in postmenopausal estrogen sensitive breast cancer patients. Type I aromatase inhibitors such as exemestane are steroidal inhibitors, which have androstenedione like structure and bind to androgen receptor with low affinity. Type II aromatase inhibitors such as anastrozole and letrozole are known as non-steroidal inhibitors, which are non-competitive inhibitors of aromatase. Sex steroid hormones such as estrogen and androgen play important roles in the maintenances of female and male bone tissues. It is well known that adult women have less bone mass than men. Especially after menopause, adult women loss their bone mass more rapidly than men of comparable age do. Therefore, many clinical reports of breast cancer patients treated with aromatase inhibitors have emphasized potential bone loss caused by aromatase inhibition. Several basic researches using animal model or in vitro model demonstrated the different effects of steroid and non-steroid aromatase inhibitors on bone tissues and cells. In this review, we summarize the effects of AIs on bone tissues reported in clinical studies and animal/in vitro studies.
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Affiliation(s)
- Yasuhiro Miki
- Department of Pathology, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi 980 8575, Japan
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Miki Y, Suzuki T, Hatori M, Igarashi K, Aisaki KI, Kanno J, Nakamura Y, Uzuki M, Sawai T, Sasano H. Effects of aromatase inhibitors on human osteoblast and osteoblast-like cells: a possible androgenic bone protective effects induced by exemestane. Bone 2007; 40:876-87. [PMID: 17254854 DOI: 10.1016/j.bone.2006.11.029] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2006] [Revised: 11/06/2006] [Accepted: 11/14/2006] [Indexed: 10/01/2022]
Abstract
Effects of aromatase inhibitors (AIs) on the human skeletal system due to systemic estrogen depletion are becoming clinically important due to their increasing use as an adjuvant therapy in postmenopausal women with breast cancer. However, possible effects of AIs on human bone cells have remained largely unknown. We therefore studied effects of AIs including the steroidal AI, exemestane (EXE), and non-steroidal AIs, Aromatase Inhibitor I (AI-I) and aminoglutethimide (AGM), on a human osteoblast. We employed a human osteoblast cell line, hFOB, which maintains relatively physiological status of estrogen and androgen pathways of human osteoblasts, i.e., expression of aromatase, androgen receptor (AR), and estrogen receptor (ER) beta. We also employed osteoblast-like cell lines, Saos-2 and MG-63 which expressed aromatase, AR, and ERalpha/beta in order to further evaluate the mechanisms of effects of AIs on osteoblasts. There was a significant increment in the number of the cells following 72 h treatment with EXE in hFOB and Saos-2 but not in MG-63, in which the level of AR mRNA was lower than that in hFOB and Saos-2. Alkaline phosphatase activity was also increased by EXE treatment in hFOB and Saos-2. Pretreatment with the AR blocker, flutamide, partially inhibited the effect of EXE. AI-I exerted no effects on osteoblast cell proliferation and AGM diminished the number of the cells. hFOB converted androstenedione into E2 and testosterone (TST). Both EXE and AI-I decreased E2 level and increased TST level. In a microarray analysis, gene profile patterns following treatment with EXE demonstrated similar patterns as with DHT but not with E2 treatment. The genes induced by EXE treatment were related to cell proliferation, differentiation which includes genes encoding cytoskeleton proteins. We also examined the expression levels of these genes using quantitative RT-PCR in hFOB and Saos-2 treated with EXE and DHT and with/without flutamide. HOXD11 gene known as bone morphogenesis factor and osteoblast growth-related genes were induced by EXE treatment as well as DHT treatment in both hFOB and Saos-2. These results indicated that the steroidal aromatase inhibitor, EXE, stimulated hFOB cell proliferation via both AR dependent and independent pathways.
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Affiliation(s)
- Yasuhiro Miki
- Department of Pathology, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan
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Ogirima T, Tano K, Kanehara M, Gao M, Wang X, Guo Y, Zhang Y, Guo L, Ishida T. Sex difference of adenine effects in rats: renal function, bone mineral density and sex steroidogenesis. Endocr J 2006; 53:407-13. [PMID: 16723811 DOI: 10.1507/endocrj.k05-009] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Adenine is widely used in clinical field, however, an excess of adenine is harmful. It is known that the feeding of an adenine-rich diet induces renal failure and decreases bone mineral density (BMD) and the serum testosterone level in male rats. However, there is little information about the influence of adenine on female animals. We compared the effects of adenine treatment between male and female rats. Young male and female rats were administered adenine adjusted with distilled water (6 mg/ml, 50 mg/ml and 100 mg/ml) for 8 weeks (3 times/week, 8-16 week old). In male rats, renal failure was induced by 100 mg/ml adenine treatment and renal dysfunction was induced by 50 mg/ml adenine treatment. Bone loss and the reduction of the testosterone level were also caused by both concentrations of adenine. However, the serum testosterone level and BMD in male rats were decreased by 6 mg/ml adenine treatment by which renal dysfunction was not caused. It is suggested that adenine directly affected bone metabolism and sex steroidgenesis in male animals, not through altering renal dysfunction. In female rats, conversely, renal dysfunction was induced only in the 100 mg/ml group, which was somewhat different from the observation in male rats. The serum 17-beta estradiol level and the BMD in female rats were not affected by adenine treatment at all. In conclusion, there is a significant difference of the effects of adenine, which is commonly contained in medicine and general foods, on steroidgenesis and renal function between male and female rats.
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Affiliation(s)
- Takeshi Ogirima
- Graduate school of Health Science, Suzuka University of Medical Science, Suzuka, Mie, Japan
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29
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Navara KJ, Hill GE, Mendonca MT. Yolk Testosterone Stimulates Growth and Immunity in House Finch Chicks. Physiol Biochem Zool 2006; 79:550-5. [PMID: 16691520 DOI: 10.1086/501054] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/01/2005] [Indexed: 11/04/2022]
Abstract
Female birds deposit variable amounts of androgens, such as testosterone, into the yolks of their eggs. Evidence suggests that yolk androgens play an important role in the determination of offspring phenotype. While androgens are generally regarded as anabolic and immunosuppressive, studies of the behavioral and physiological effects of yolk androgens on offspring of several avian species have been conflicting, leaving the adaptive significance associated with deposition patterns of yolk androgens unclear. We injected either a physiological dose of testosterone or a control vehicle into house finch (Carpodacus mexicanus) eggs and examined the effects of these injections on offspring growth and immunity. Two days after hatching, nestlings from eggs treated with testosterone were significantly larger than nestlings from eggs treated with a control injection, suggesting a stimulatory effect of yolk androgens in early development. By 8 d after hatching, however, this effect disappeared, and chicks from the two treatment groups were similar in size. Nestlings in the testosterone treatment group showed a significantly larger swelling response to phytohemagglutinin than control nestlings 15 d after hatching, which is close to fledging. Overall, our observations show that when food resources are abundant, testosterone stimulates both early growth and immunity in developing house finches.
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Affiliation(s)
- Kristen J Navara
- Department of Biological Sciences, Auburn University, AL 36849, USA.
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30
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Mi LY, Basu M, Fritton SP, Cowin SC. Analysis of avian bone response to mechanical loading. Part two: Development of a computational connected cellular network to study bone intercellular communication. Biomech Model Mechanobiol 2005; 4:132-46. [PMID: 16365733 DOI: 10.1007/s10237-004-0066-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2004] [Accepted: 12/06/2004] [Indexed: 10/25/2022]
Abstract
Mechanical loading-induced signals are hypothesized to be transmitted and integrated by connected bone cells before reaching the bone surfaces where adaptation occurs. A computational connected cellular network (CCCN) model is developed to explore how bone cells perceive and transmit the signals through intercellular communication. This is part two of a two-part study in which a CCCN is developed to study the intercellular communication within a grid of bone cells. The excitation signal was computed as the loading-induced bone fluid shear stress in part one. Experimentally determined bone adaptation responses (Gross et al. in J Bone Miner Res 12:982-988, 1997 and Judex et al. in J Bone Miner Res 12:1737-1745, 1997) are correlated with the fluid shear stress by the CCCN, which adjusts cell sensitivities (loading and signal thresholds) and connection weights. Intercellular communication patterns extracted by the CCCN indicate the cell population responsible for perceiving the loading-induced signal, and loading threshold is shown to play an important role in regulating the bone response.
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Affiliation(s)
- Li Y Mi
- Department of Electrical Engineering, New York Center for Biomedical Engineering, The City College of New York/CUNY, 10031, New York, USA
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31
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Abstract
TGF-beta1 is a ubiquitous growth factor that is implicated in the control of proliferation, migration, differentiation, and survival of many different cell types. It influences such diverse processes as embryogenesis, angiogenesis, inflammation, and wound healing. In skeletal tissue, TGF-beta1 plays a major role in development and maintenance, affecting both cartilage and bone metabolism, the latter being the subject of this review. Because it affects both cells of the osteoblast and osteoclast lineage, TGF-beta1 is one of the most important factors in the bone environment, helping to retain the balance between the dynamic processes of bone resorption and bone formation. Many seemingly contradictory reports have been published on the exact functioning of TGF-beta1 in the bone milieu. This review provides an overall picture of the bone-specific actions of TGF-beta1 and reconciles experimental discrepancies that have been reported for this multifunctional cytokine.
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Affiliation(s)
- Katrien Janssens
- Department of Medical Genetics, University of Antwerp, Campus Drie Eiken, 2610 Antwerp, Belgium
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32
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Navara KJ, Hill GE, Mendonca MT. Variable Effects of Yolk Androgens on Growth, Survival, and Immunity in Eastern Bluebird Nestlings. Physiol Biochem Zool 2005; 78:570-8. [PMID: 15957111 DOI: 10.1086/430689] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/20/2004] [Indexed: 11/03/2022]
Abstract
Female birds allocate androgens differentially within and among clutches, and it has been suggested that this is a strategy to maximize reproductive success. Only a few studies, however, have examined the effects of yolk testosterone (T) on the growth and development of nestlings, and none have reported on the immunological effects of yolk T nor have they examined several different effects in the same nestlings. To examine the effects of yolk T on nestling eastern bluebirds, we administered two doses of exogenous T to bluebird eggs and measured the growth and immunological responsiveness in the resulting nestlings. We found that yolk T is detrimental to developing embryos, with hatching success decreasing with increasing doses of yolk T. Moderate doses of yolk T stimulated skeletal growth during the embryonic period, while high doses of yolk T resulted in nestlings that weighed more and were more mature at fledging but had a compromised T-cell immune response to phytohemagglutinin. These data suggest that the alteration of reproductive success through the allocation of yolk T is a complicated phenomenon that involves the integration of several physiological effects.
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Affiliation(s)
- Kristen J Navara
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA.
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33
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Choi BH, Zhu SJ, Kim BY, Huh JY, Lee SH, Jung JH. Effect of platelet-rich plasma (PRP) concentration on the viability and proliferation of alveolar bone cells: an in vitro study. Int J Oral Maxillofac Surg 2005; 34:420-4. [PMID: 16053853 DOI: 10.1016/j.ijom.2004.10.018] [Citation(s) in RCA: 166] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2004] [Revised: 06/15/2004] [Accepted: 10/25/2004] [Indexed: 02/06/2023]
Abstract
Previous studies have shown that a combination of platelet-rich plasma (PRP) and autogenous bone graft can increase the rate of osteogenesis and enhance bone formation qualitatively. However, contradictory results were reported in a recent animal study. In order to clarify this inconsistency, this study examined the influence of the PRP concentrations on the viability and proliferation of alveolar bone cells in vitro. Bone cells obtained from the alveolar bone chips were exposed to various PRP concentrations. After a culture period of 7 days, cellular viability and proliferation were evaluated by counting the number of cells and a MTT assay. The results showed that the viability and proliferation of alveolar bone cells were suppressed by high PRP concentrations, but were stimulated by low PRP concentrations (1-5%). These in vitro results support the view that variations in the PRP concentrations might influence the bone formation within the PRP-treated bone grafts.
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Affiliation(s)
- B-H Choi
- Department of Oral and Maxillofacial Surgery, College of Dentistry, Wonju Christian Hospital, Yonsei University (Brain Korea 21 Project for Medical Sciences), 162 Ilsan-Dong, Wonju, Kangwon-Do, Seoul, South Korea.
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34
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Abstract
Sex steroids play a major role in the regulation of bone turnover. Thus, gonadectomy in either sex is associated with an increase in bone remodeling, increased bone resorption, and a relative deficit in bone formation, resulting in accelerated bone loss. Recent physiological studies have established an important role for estrogen in regulating bone turnover not only in females, but also in males. Studies in mice with knock out of the estrogen receptor, aromatase, or androgen receptor have provided important insights into the in vivo mechanisms of sex steroid action on bone. The cellular and molecular mediators of sex steroid effects on the bone-forming osteoblasts and bone-resorbing osteoclasts are also being increasingly better defined. Estrogen inhibits bone remodeling by concurrently suppressing osteoblastogenesis and osteoclastogenesis from marrow precursors. Both estrogen and androgens inhibit bone resorption via effects on the receptor activator of NF-kappaB ligand (RANKL)/RANK/osteoprotegerin system, as well as by reducing the production of a number of pro-resorptive cytokines, along with direct effects on osteoclast activity and lifespan. Sex steroid effects on bone formation are also likely mediated by multiple mechanisms, including a prolongation of osteoblast lifespan via non-genotropic mechanisms, as well as effects on osteoblast differentiation and function. These pleiotropic actions of sex steroids on virtually all aspects of bone metabolism belie the importance of the skeleton not only in providing structural support for the body and in locomotion, but also as a dynamic tissue responsive, among other things, to the reproductive needs of the organism for calcium.
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Affiliation(s)
- Farhan Syed
- Mayo Clinic College of Medicine, Rochester, MN, USA
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35
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Cancer Treatment-Induced Bone Loss (CTIBL) in Prostate Cancer: Pathophysiology, Preclinical Findings, and Treatment with Zoledronic Acid. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.eursup.2004.08.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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36
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Abstract
Loss of estrogens or androgens increases the rate of bone remodeling by removing restraining effects on osteoblastogenesis and osteoclastogenesis, and also causes a focal imbalance between resorption and formation by prolonging the lifespan of osteoclasts and shortening the lifespan of osteoblasts. Conversely, androgens, as well as estrogens, maintain cancellous bone mass and integrity, regardless of age or sex. Although androgens, via the androgen receptor (AR), and estrogens, via the estrogen receptors (ERs), can exert these effects, their relative contribution remains uncertain. Recent studies suggest that androgen action on cancellous bone depends on (local) aromatization of androgens into estrogens. However, at least in rodents, androgen action on cancellous bone can be directly mediated via AR activation, even in the absence of ERs. Androgens also increase cortical bone size via stimulation of both longitudinal and radial growth. First, androgens, like estrogens, have a biphasic effect on endochondral bone formation: at the start of puberty, sex steroids stimulate endochondral bone formation, whereas they induce epiphyseal closure at the end of puberty. Androgen action on the growth plate is, however, clearly mediated via aromatization in estrogens and interaction with ERalpha. Androgens increase radial growth, whereas estrogens decrease periosteal bone formation. This effect of androgens may be important because bone strength in males seems to be determined by relatively higher periosteal bone formation and, therefore, greater bone dimensions, relative to muscle mass at older age. Experiments in mice again suggest that both the AR and ERalpha pathways are involved in androgen action on radial bone growth. ERbeta may mediate growth-limiting effects of estrogens in the female but does not seem to be involved in the regulation of bone size in males. In conclusion, androgens may protect men against osteoporosis via maintenance of cancellous bone mass and expansion of cortical bone. Such androgen action on bone is mediated by the AR and ERalpha.
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Affiliation(s)
- Dirk Vanderschueren
- Laboratory for Experimental Medicine and Endocrinology, Katholieke Universiteit Leuven, Leuven, Belgium
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37
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Inui A, Itamoto K, Takuma T, Tsutsumi H, Tanigawa M, Hayasaki M, Taura Y, Mamba K. Age-Related Changes of Bone Mineral Density and Microarchitecture in Miniature Pigs. J Vet Med Sci 2004; 66:599-609. [PMID: 15240933 DOI: 10.1292/jvms.66.599] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Bone mineral density (BMD), distribution of its density and bone histomorphometric parameters were evaluated in lumbar vertebra of normally growing miniature pigs. The fourth lumbar vertebra (L4) of the Göttingen miniature pig were used in this cross-sectional study in vitro. The BMD of the miniature pig was similar to that of humans in tendency of gender differences and some growth patterns during puberty. In these regards this animal appears useful as a model for human bone study. However, the trabecular and cortical BMDs of lumbar spine were extremely high value (399.43 +/- 26.36 mg/cm(3) in female trabeculae; 973.06 +/- 69.55 mg/cm(3) in female cortical bone; 419.04 +/- 34.84 mg/cm(3) in male trabeculae; 1038.81 +/- 125.72 mg/cm(3) in male cortical bone in pigs 30 months or more). Furthermore, histomorphometric analysis yielded values that were remarkably different from those found in humans. From these results, it was revealed that miniature pig had a higher bone mass and denser trabecular network than human, indicating that its bone is probably stronger. Therefore, care should be taken in choosing the miniature pig as a bone study model.
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Affiliation(s)
- Azusa Inui
- Department of Veterinary Hospital, Faculty of Agriculture, Yamaguchi University, Japan
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38
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Overstreet M, Floyd T, Polotsky A, Hungerford DS, Frondoza CG. Enhancement of osteoblast proliferative capacity by growth factor-like molecules in bear serum. In Vitro Cell Dev Biol Anim 2003; 39:4-7. [PMID: 12892520 DOI: 10.1290/1543-706x(2003)039<0004:eoopcb>2.0.co;2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The use of animal serum in cell culture is vital for providing the nutrient factors required to promote proliferation and function. Fetal calf serum has become the preferred choice because of its abundance, reasonable cost, and ability to sustain human cells in vitro. Although a wide variety of serum sources have been tested and used, little is known about the ability of serum obtained from the American black bear (Ursus americanus) to support human cell growth in culture. The American black bear, an animal comparable in size to humans, is unique in that it hibernates for mo at a time but does not experience extensive bone loss normally associated with extended immobility. The aim of this study was to analyze the effect of bear serum on human osteoblast cultures. We discovered that three of the eight bear serum samples induced significantly higher proliferation rates in osteoblasts than did fetal calf serum over a 24-h period. Osteoblasts incubated in bear serum displayed higher messenger ribonucleic acid levels for phenotype markers osteocalcin and type I collagen than did those incubated in fetal calf serum. The mitogenic activity of the bear serum was reduced when heated at 56 degrees C for 30 min before use in culture. The molecular weight of the mitogenic factors was found to be primarily greater than 50 kDa. The present work demonstrates the capability of serum from American black bears to support human osteoblast proliferation in vitro.
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Affiliation(s)
- Michael Overstreet
- Division of Arthritis Surgery, Department of Orthopaedic Surgery, The Good Samaritan Hospital, The Johns Hopkins University, Baltimore, Maryland 21239, USA
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39
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Abstract
Growth, adolescent sexual development and changes in body composition are described in male adolescents. The underlying changes in the hypothalamic-pituitary gonadal and the GH/IGF-I axes that underline the physical changes are then described. Finally, how high energy output, at a time of low energy input, using, as an example, scholastic male wrestlers, is described.
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Affiliation(s)
- Alan D Rogol
- University of Virginia, Department of Pediatrics, Box 800386, Charlottesville, VA 22908, USA.
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40
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Liegibel UM, Sommer U, Tomakidi P, Hilscher U, Van Den Heuvel L, Pirzer R, Hillmeier J, Nawroth P, Kasperk C. Concerted action of androgens and mechanical strain shifts bone metabolism from high turnover into an osteoanabolic mode. J Exp Med 2002; 196:1387-92. [PMID: 12438430 PMCID: PMC2193981 DOI: 10.1084/jem.20021017] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Adhesion of bone cells to the extracellular matrix is a crucial requirement for osteoblastic development and function. Adhesion receptors connect the extracellular matrix with the cyto-skeleton and convey matrix deformation into the cell. We tested the hypothesis that sex hormones modulate mechanoperception of human osteoblastic cells (HOB) by affecting expression of adhesion molecules like fibronectin and the fibronectin receptor. Only dihydrotestosterone (DHT), but not 17beta-estradiol, stimulated fibronectin (137%) and fibronectin receptor (252%) protein expression. The effects of deformation strain on HOB metabolism were investigated in a FlexerCell strain unit. Cyclically applied strain (2.5% elongation) increased DNA synthesis (125%) and interleukin-6 (IL-6) production (170%) without significantly affecting alkaline phosphatase (AP) activity, type I collagen (PICP), or osteoprotegerin (OPG) secretion. 10 nM DHT pretreatment abolished the mitogenic response of HOB to strain and increased AP activity (119%), PICP (163%), and OPG production (204%). In conclusion, mechanical strain stimulates bone remodeling by increasing HOB mitosis and IL-6 production. DHT enhances the osteoanabolic impact of deformation strain by increasing bone formation via increased AP activity and PICP production. At the same time, bone resorption is inhibited by decreased IL-6 and increased OPG secretion into the bone microenvironment.
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Affiliation(s)
- Ute M Liegibel
- Department of Medicine, Division of Osteology, Ruprecht-Karls-University, 69115 Heidelberg, Germany
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41
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Abstract
Here we review and extend a new unitary model for the pathophysiology of involutional osteoporosis that identifies estrogen (E) as the key hormone for maintaining bone mass and E deficiency as the major cause of age-related bone loss in both sexes. Also, both E and testosterone (T) are key regulators of skeletal growth and maturation, and E, together with GH and IGF-I, initiate a 3- to 4-yr pubertal growth spurt that doubles skeletal mass. Although E is required for the attainment of maximal peak bone mass in both sexes, the additional action of T on stimulating periosteal apposition accounts for the larger size and thicker cortices of the adult male skeleton. Aging women undergo two phases of bone loss, whereas aging men undergo only one. In women, the menopause initiates an accelerated phase of predominantly cancellous bone loss that declines rapidly over 4-8 yr to become asymptotic with a subsequent slow phase that continues indefinitely. The accelerated phase results from the loss of the direct restraining effects of E on bone turnover, an action mediated by E receptors in both osteoblasts and osteoclasts. In the ensuing slow phase, the rate of cancellous bone loss is reduced, but the rate of cortical bone loss is unchanged or increased. This phase is mediated largely by secondary hyperparathyroidism that results from the loss of E actions on extraskeletal calcium metabolism. The resultant external calcium losses increase the level of dietary calcium intake that is required to maintain bone balance. Impaired osteoblast function due to E deficiency, aging, or both also contributes to the slow phase of bone loss. Although both serum bioavailable (Bio) E and Bio T decline in aging men, Bio E is the major predictor of their bone loss. Thus, both sex steroids are important for developing peak bone mass, but E deficiency is the major determinant of age-related bone loss in both sexes.
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Affiliation(s)
- B Lawrence Riggs
- Division of Endocrinology and Metabolism, Department of Health Sciences Research, Mayo Clinic and Mayo Foundation, 200 First Street SW, Rochester, Minnesota 55905, USA.
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42
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Dale JB, Sarich SL, Bretz TM, Hatton JF, Zachow RJ. Hormonal regulation of androgen receptor messenger ribonucleic acid expression in human tooth pulp. J Dent Res 2002; 81:360-5. [PMID: 12097452 DOI: 10.1177/154405910208100514] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Tooth pulp contains steroid receptors and therefore is likely to respond to steroids. Steroids and cytokines together can alter steroid receptor content in many tissues; thus, similar mechanisms may exist in tooth pulp. In this study, reverse-transcription/polymerase chain-reaction was used to screen human pulp for the mRNAs encoding receptors for androgen (AR), estrogens (ERbeta), and hepatocyte growth factor (HGF: c-Met). AR mRNA content was greater in male pulp vs. female pulp in all age groups. In both genders, AR mRNA content diminished with age. In pulp cell cultures, androstenedione, estradiol-17beta, and HGF each stimulated AR mRNA accumulation. Testosterone inhibited, whereas 5alpha-dihydrotestosterone did not affect, AR mRNA content. ERbeta was not hormonally altered in pulp cell cultures. By showing steroid- and cytokine-orchestrated regulation of AR mRNA in vitro, it is possible that age- and/or pathogen-dependent changes in available steroids and cytokines can affect any androgen-responsiveness of pulp.
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Affiliation(s)
- J B Dale
- Department of Endodontics, St. Louis University Center for Advanced Dental Education, St. Louis, MO, USA
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43
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Abstract
Bone health and strength are dependent on the coupling of cone resorption and bone formation. This process is governed by the interaction of osteoclasts and osteoblasts plus the modulating influence of the bone mechanicosensory cells-the osteocytes. Both sex steroids-estrogen (E) and testosterone (T)- have receptors on all bone cells, with androgen dominance on osteoblasts and osteocytes. Specific receptors for the weaker androgens, such as DHEA have also been identified. The activity of the sex steroids, influenced by various enzymes found in bone, is reflective of the hormone ligand before its binding to the bone cells. As a result, T acts both directly and via its aromatization to estradiol. The activity of the androgens also varies with the bone surface; periosteal cells, for example, do not have 5alpha-reductase activity, indicating that T is the active metabolite at this clinically important site. Androgens influence bone cell function via local and systemic growth factors and cytokines. By enhancing osteoblast differentiation, androgens regulate bone matrix production, organization, and mineralization. Androgens also regulate osteoclast recruitment and activity. Endogenous androgens increase bone mineral density (BMD) in both adolescent and adult premenopausal women. Women with excess endogenous androgen-for example, those with hirsutism and polycystic ovary syndrome (PCOS)-have increased BMD compared with normal young women. E and androgen therapy increases BMD to a greater degree than does E therapy alone. This is true for both oral combinations of esterified E and methyltestosterone and for subcutaneous T implants. Androgenic progestins have an additive effect on BMD when combined with E therapy and have the further advantage of being protective to the endometrium in E-treated women. Androgens increase muscle mass and strength. The resulting improvement in physical activity leads to the activation of bone-forming sites and the stimulation of the bone formation-modulating cells, the osteocytes. Mechanical loading, when combined with hormone therapy, results in greater osteogenic response than does either alone.
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44
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Pepene CE, Kasperk CH, Pfeilschifter J, Börcsök I, Gozariu L, Ziegler R, Seck T. Effects of triiodothyronine on the insulin-like growth factor system in primary human osteoblastic cells in vitro. Bone 2001; 29:540-6. [PMID: 11728924 DOI: 10.1016/s8756-3282(01)00607-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Thyroid hormone plays a major role in the regulation of bone metabolism but the mechanism by which this is accomplished is not clear. Interactions of thyroid hormone with the growth hormone/insulin-like growth factors (IGFs) axis suggest an alternate pathway of action for triiodothyronine (T(3)) on bone formation, besides direct effects. The present study investigates the influence of T(3) on IGF-1, IGF-2, IGF-1 receptor (IGF-1R), and IGF binding protein (IGFBP) transcripts, and on IGF-1 action in human osteoblastic cells (hOB) under serum-free culture conditions. No influence of T(3) on IGF-1, IGF-2, IGFBP-3, or IGFBP-4 mRNA levels in hOB was observed. However, T(3) at concentrations of 10(-8) mol/L and 10(-7) mol/L increased IGF-1R mRNA levels in a dose-dependent manner (p < 0.01) and enhanced IGFBP-5 mRNA levels at a concentration of 10(-7) mol/L (p < 0.05), as assessed by reverse transcriptase-polymerase chain reaction. Correspondingly, Scatchard analysis of [(125)I]-IGF-1 binding revealed that T(3) at 10(-7) mol/L increased the number of IGF-1 binding sites in hOB, with small changes in receptor affinity. In addition, a synergistic effect of T(3) and IGF-1 on hOB proliferation was found (p < 0.05). We conclude that IGF-1R and IGFBP-5 are thyroid hormone target genes in human osteoblasts, whereas IGF-1 mRNA expression itself appears not to be regulated by T(3) in hOB. However, T(3) stimulates IGF-1R mRNA expression as well as IGF-1 binding and IGF-1 induced cell proliferation in osteoblasts, thus suggesting thyroid hormone may potentiate the effect of IGF-1 at the receptor level. This may contribute to the positive effects of thyroid hormone on bone formation, which, in addition, may be modulated by increased IGFBP-5 expression.
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Affiliation(s)
- C E Pepene
- Department of Internal Medicine I, University of Heidelberg, Heidelberg, Germany.
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45
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Antus B, Yao Y, Liu S, Song E, Lutz J, Heemann U. Contribution of androgens to chronic allograft nephropathy is mediated by dihydrotestosterone. Kidney Int 2001; 60:1955-63. [PMID: 11703615 DOI: 10.1046/j.1523-1755.2001.00007.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Donor and recipient gender influence long-term allograft outcome after kidney transplantation. Sex hormones are likely to contribute to these gender-related differences. The present study investigated the role of androgens and their inhibition on the development of chronic allograft nephropathy. METHODS Male or female Fisher (F344) kidneys were orthotopically transplanted into intact male Lewis recipients. Animals were treated either with testosterone, the antiandrogen flutamide, the 5alpha-reductase inhibitor finasteride, or vehicle. Twenty weeks after transplantation animals were harvested for histology, immunohistology, and molecular analysis. RESULTS Testosterone treatment resulted in an increased proteinuria as well as profound glomerulosclerosis, tubulointerstitial fibrosis, and mononuclear cell infiltration that paralleled enhanced intragraft mRNA levels of transforming growth factor-beta (TGF-beta) and platelet-derived growth factor-A and -B chain (PDGF-A and -B). In contrast, flutamide and finasteride reduced glomerulosclerosis as well as the inflammatory cell infiltration associated with decreased TGF-beta, PDGF-A, and -B chain mRNA expression. No gender-related donor differences were noted between the groups. CONCLUSIONS Our data suggest that dihydrotestosterone mediates the adverse effects of androgens on chronic allograft nephropathy. The inhibition of androgens improves long-term allograft outcome after kidney transplantation.
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Affiliation(s)
- B Antus
- Department of Nephrology, University Hospital Essen, D-45122 Essen, Germany
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46
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Onobrakpeya OA, Fall PM, Willard A, Chakravarthi P, Hansen A, Raisz LG. Effect of norethindrone acetate on hormone levels and markers of bone turnover in estrogen-treated postmenopausal women. Endocr Res 2001; 27:473-80. [PMID: 11794470 DOI: 10.1081/erc-100107870] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
There is controversy concerning the effects of progestins on bone. Norethindrone acetate (NETA) is synthetic progesterone that also has estrogenic and androgenic effects. We tested its effects on hormone levels, lipids and biochemical markers of bone turnover in postmenopausal women who were on estrogen replacement therapy. Women were treated with NETA, 5 mg/d for 9 weeks. Estrogenic effects included a marked lowering of follicle stimulating hormone and luteinizing hormone. Androgenic effects included a decrease in sex hormone binding globulin and HDL cholesterol. Bone turnover showed inconsistent responses. Among markers of bone formation, bone specific alkaline phosphatase decreased significantly by 23% while procollagen peptides and osteocalcin showed a non-significant increase. The marker of bone resorption, N-telopeptide crosslinks of collagen, decreased by 19% at 6 weeks. These results indicate that NETA does not have a potent short-term anabolic effect on bone but does have effects that are likely to be mediated through the estrogen and androgen receptors.
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Affiliation(s)
- O A Onobrakpeya
- Division of Endocrinology and Metabolism, Lowell P. Weicker, General Clinical Research Center, University of Connecticut Health Center, Farmington, USA
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47
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Wang C, Swerdloff RS, Iranmanesh A, Dobs A, Snyder PJ, Cunningham G, Matsumoto AM, Weber T, Berman N. Effects of transdermal testosterone gel on bone turnover markers and bone mineral density in hypogonadal men. Clin Endocrinol (Oxf) 2001; 54:739-50. [PMID: 11422108 DOI: 10.1046/j.1365-2265.2001.01271.x] [Citation(s) in RCA: 131] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE Androgen replacement has been reported to increase bone mineral density (BMD) in hypogonadal men. We studied the effects of 6 months of treatment with a new transdermal testosterone (T) gel preparation on bone turnover markers and BMD. DESIGN This was a prospective, randomized, multicentre, parallel clinical trial where 227 hypogonadal men, mean age 51 years (range: 19-68 years) were studied in 16 academic and research institutions in the USA. Subjects were randomized to apply 1% T gel containing 50 or 100 mg T (delivering approximately 5-10 mg T/day) or two T patches (delivering 5 mg T/day) transdermally for 90 days. At day 91, depending on the serum T concentration, the T gel dose was adjusted upward or downward to 75 mg T/day until day 180. No dose adjustment occurred in the T patch group. MEASUREMENTS Serum T, free T and oestradiol, bone turnover markers and BMD were measured on days 0, 30, 90 and 180 before and after treatment. RESULTS Application of T gel 100 mg/day resulted in serum T concentrations 1.4 and 1.9-fold higher than in the T gel 50 mg/day and the T patch groups, respectively. Proportional increases occurred in serum oestradiol. Urine N-telopeptide/creatinine ratio, a marker for bone resorption, decreased significantly (P = 0.0019) only in the T gel 100 mg/day group. Serum bone osteoblastic activity markers (osteocalcin, procollagen and skeletal alkaline phosphatase) increased significantly during the first 90 days of treatment without intergroup differences but declined to baseline thereafter. BMD increased significantly both in the hip (+1.1 +/- 0.3%) and spine (+2.2 +/- 0.5%) only in the T gel 100 mg/day group (P = 0.0001). CONCLUSIONS Transdermal testosterone gel application for 6 months decreased bone resorption markers and increased osteoblastic activity markers for a short period, which resulted in a small but significant increase in BMD. Ongoing long-term studies should answer whether the observed increases in BMD are sustained or continue to be dependent on the dose of testosterone administered.
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Affiliation(s)
- C Wang
- Divisions of Endocrinology, Department of Medicine, Harbor-UCLA Medical Center and Research and Education Institute, Torrance, CA, USA.
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Nnodim JO. Testosterone mediates satellite cell activation in denervated rat levator ani muscle. THE ANATOMICAL RECORD 2001; 263:19-24. [PMID: 11331967 DOI: 10.1002/ar.1072] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Denervation stimulates quiescent satellite cells in skeletal muscle to reenter the cell cycle. In the androgen-sensitive rat levator ani muscle (LA), this mitotic response to loss of neural input fails to occur in castrated animals. To elucidate the role of androgens in denervation-induced satellite cell proliferation, the denervated LA of castrated rats (Group A) was compared with that of animals infixed with testosterone implants after castration (Group B). Mean myofiber cross-sectional areas (Group A: 362.95 microm(2) +/- 27.74; Group B: 403.13 microm(2) +/- 53.87) and linear nuclear densities (Group A: 74.07 mm(-1) +/- 17.58; Group B: 104.13 mm(-1) +/- 4.06) were similar (P > 0.05) in both groups. The androgen-deprived myofibers of Group A, however, had a significantly lower nuclear content (271.0 +/- 74.91 vs. 1,285.80 +/- 81.74 in Group B; P < 0.05) on account of their considerably shorter mean length (3.44 mm +/- 0.29 vs. 12.31 mm +/- 0.92 in Group B; P < 0.05). The proportional representation of satellite cells in hormone-replaced, denervated muscle was more than twice that in the untreated group (Group B: 5.15 +/- 0.83% vs. Group A: 2.28 +/- 0.23%; P < 0.05). In absolute terms, the satellite cell number in Group B was approximately an order of magnitude greater than in Group A (408.4 x 10(3) vs. 38.08 x 10(3)). The results confirm the absence of testosterone as the factor responsible for the inability of satellite cells in the LA of castrated rats to respond mitotically to the withdrawal of neural input after denervation.
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Affiliation(s)
- J O Nnodim
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan 48109-2007, USA
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Fujita T, Kawata T, Tokimasa C, Tanne K. Influence of oestrogen and androgen on modelling of the mandibular condylar bone in ovariectomized and orchiectomized growing mice. Arch Oral Biol 2001; 46:57-65. [PMID: 11163596 DOI: 10.1016/s0003-9969(00)00094-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Oestrogen and androgen exert a substantial influence on bone metabolism, but any differences in their influence on modelling of the condyle, a mandibular growth site, have not been fully clarified. The purpose here was to examine histological and histochemical differences in the condyle of ovariectomized (OVX) or orchiectomized (ORX) mice given injections of oestrogen (E(2), 17 beta-oestradiol) or non-aromatizable androgen (DHT, 5 alpha-dihydrotestosterone). Eight-week-old C57BL/6J mice (n=170) were used: they were divided equally into six experimental groups (OVX, ORX, OVX+E(2), ORX+E(2), OVX+DHT, ORX+DHT), and non-treatment male and female control groups. In each experimental group, five mice were killed 2,4,8 and 12 weeks after OVX and ORX. Oestrogen or androgen were given daily after the surgery by subcutaneous injection of E(2) or DHT. Increases in the number of tartrate-resistant acid phosphatase-positive cells induced in the OVX and ORX mice from 4 to 12 weeks after surgery were obviously suppressed by E(2) and DHT. The trabecular bone volume in the OVX and ORX mice treated with DHT had only increased at 12 weeks after surgery, whereas the E(2) injected mice exhibited a substantial increase from 4 to 12 weeks after surgery. E(2) injected into the OVX and ORX mice increased the trabecular bone volume earlier than did DHT, and both E(2) and DHT suppressed osteoclast differentiation similarly during the same period. These results suggest that metabolic responses of osteoclasts and osteoblasts to E(2) and DHT may be different, producing somewhat different patterns of bone modelling in males and females.
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Affiliation(s)
- T Fujita
- Department of Orthodontics, Hiroshima University Faculty of Dentistry, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan.
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Abstract
Sex steroids are essential for skeletal development and the maintenance of bone health throughout adult life, and estrogen deficiency at menopause is a major pathogenetic factor in the development of osteoporosis in postmenopausal women. The mechanisms by which the skeletal effects of sex steroids are mediated remain incompletely understood, but in recent years there have been considerable advances in our knowledge of how estrogens and, to a lesser extent androgens, influence bone modeling and remodeling in health and disease. New insights into estrogen receptor structure and function, recent discoveries about the development and activity of osteoclasts, and lessons learned from human and animal genetic mutations have all contributed to increased understanding of the skeletal effects of estrogen, both in males and females. Studies of untreated and treated osteoporosis in postmenopausal women have also contributed to this knowledge and have provided unequivocal evidence for the potential of high-dose estrogen therapy to have anabolic skeletal effects. The development of selective estrogen receptor modulators has provided a new approach to the prevention of osteoporosis and other major diseases of menopause and has implications for the therapeutic use of other steroid hormones, including androgens. Further elucidation of the mechanisms by which sex steroids affect bone thus has the potential to improve the clinical management not only of osteoporosis, both in men and women, but also of a number of other diseases related to sex hormone status.
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Affiliation(s)
- J E Compston
- Department of Medicine, University of Cambridge School of Clinical Medicine, Cambridge, United Kingdom.
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