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Pilutin A, Misiakiewicz-Has K, Kolasa-Wołosiuk A, Trybek G, Urban F, Marchlewicz M, Leszczyński B, Wróbel A, Wiszniewska B. Morphology and serum and bone tissue calcium and magnesium concentrations in the bones of male rats chronically treated with letrozole, a nonsteroidal cytochrome P450 aromatase inhibitor. Connect Tissue Res 2021; 62:454-463. [PMID: 32419518 DOI: 10.1080/03008207.2020.1771329] [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] [Indexed: 02/03/2023]
Abstract
Purpose/Aim of the study: The role of estrogen (E) in the regulation of bone turnover in women is well established, though the contributions of E versus testosterone (T) in the control of bone turnover in men are poorly understood. The aim of this study was to examine the association between chronic treatment with letrozole, a nonsteroidal inhibitor blocking the aromatase activity and thus the conversion of androgens into estrogens, and cortical bone morphology in the femur and humerus of male adult rats.Materials and Methods: Adult male rats were treated with letrozole for 6 months and the body and femur weight, morphology, collagen structure, blood serum, and bone tissue concentrations of calcium and magnesium were examined.Results: Long-term aromatase inhibition resulted in a decrease in femur mass, a wavelike arrangement of bone and lamellae with an altered organization of collagen in compact bone, a increased concentration of calcium in blood serum, and no change in calcium bone tissue concentration, magnesium serum, or bone tissue concentration. MicroCT study of the humerus revealed significant decreases of whole bone tissue volume, cortical bone thickness, cortical bone volume, and external cortical bone thickness with letrozole treatment.Conclusion: Chronic treatment with letrozole affected cortical bone structure and produced histomorphological changes in male rat bone similar to that observed in the aging processes.
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Affiliation(s)
- Anna Pilutin
- Department of Histology and Embryology, Pomeranian Medical University, Szczecin, Poland
| | | | | | - Grzegorz Trybek
- Department of Dental Surgery, Pomeranian Medical University, Szczecin, Poland
| | - Fabian Urban
- Department of Histology and Embryology, Pomeranian Medical University, Szczecin, Poland
| | - Mariola Marchlewicz
- Department of Aesthetic Dermatology, Pomeranian Medical University, Szczecin, Poland
| | - Bartosz Leszczyński
- M. Smoluchowski Institute of Physics, Jagiellonian University, Krakow, Poland
| | - Andrzej Wróbel
- M. Smoluchowski Institute of Physics, Jagiellonian University, Krakow, Poland
| | - Barbara Wiszniewska
- Department of Histology and Embryology, Pomeranian Medical University, Szczecin, Poland
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2
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Choy MHV, Wong RMY, Li MC, Wang BY, Liu XD, Lee W, Cheng JCY, Chow SKH, Cheung WH. Can we enhance osteoporotic metaphyseal fracture healing through enhancing ultrastructural and functional changes of osteocytes in cortical bone with low-magnitude high-frequency vibration? FASEB J 2020; 34:4234-4252. [PMID: 31961009 DOI: 10.1096/fj.201901595r] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 12/31/2019] [Accepted: 01/07/2020] [Indexed: 01/04/2023]
Abstract
Fragility fractures are related to the loss of bone integrity and deteriorated morphology of osteocytes. Our previous studies have reported that low-magnitude high-frequency vibration (LMHFV) promoted osteoporotic fracture healing. As osteocytes are known for mechanosensing and initiating bone repair, we hypothesized that LMHFV could enhance osteoporotic fracture healing through enhancing morphological changes in the osteocyte lacuna-canalicular network (LCN) and mineralization. A metaphyseal fracture model was established in female Sprague-Dawley rats to investigate changes in osteocytes and healing outcomes from early to late phase post-fracture. Our results showed that the LCN exhibited an exuberant outgrowth of canaliculi in the osteoporotic fractured bone at day 14 after LMHFV. LMHFV upregulated the E11, dentin matrix protein 1 (DMP1), and fibroblast growth factor 23 (FGF23), but downregulated sclerostin (Sost) in osteocytes. Moreover, LMHFV promoted mineralization with significant enhancements of Ca/P ratio, mineral apposition rate (MAR), mineralizing surface (MS/BS), and bone mineral density (BMD) in the osteoporotic group. Consistently, better healing was confirmed by microarchitecture and mechanical properties, whereas the enhancement in osteoporotic group was comparable or even greater than the normal group. This is the first report to reveal the enhancement effect of LMHFV on the osteocytes' morphology and functions in osteoporotic fracture healing.
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Affiliation(s)
- Man-Huen Victoria Choy
- Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Ronald Man-Yeung Wong
- Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Meng-Chen Li
- Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Bai Yan Wang
- School of Biomedical Science, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Xiao Dong Liu
- Department of Anaesthesia and Intensive Care, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Wayne Lee
- Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Jack Chun-Yiu Cheng
- Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong SAR, China.,The CUHK-ACC Space Medicine Centre on Health Maintenance of Musculoskeletal System, The Chinese University of Hong Kong Shenzhen Research Institute, Shenzhen, PR China
| | - Simon Kwoon-Ho Chow
- Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong SAR, China.,The CUHK-ACC Space Medicine Centre on Health Maintenance of Musculoskeletal System, The Chinese University of Hong Kong Shenzhen Research Institute, Shenzhen, PR China
| | - Wing-Hoi Cheung
- Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong SAR, China.,The CUHK-ACC Space Medicine Centre on Health Maintenance of Musculoskeletal System, The Chinese University of Hong Kong Shenzhen Research Institute, Shenzhen, PR China
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3
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Glenske K, Schuler G, Arnhold S, Elashry MI, Wagner AS, Barbeck M, Neumann E, Müller-Ladner U, Schnettler R, Wenisch S. Effects of testosterone and 17β-estradiol on osteogenic and adipogenic differentiation capacity of human bone-derived mesenchymal stromal cells of postmenopausal women. Bone Rep 2019; 11:100226. [PMID: 31709277 PMCID: PMC6833309 DOI: 10.1016/j.bonr.2019.100226] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 09/11/2019] [Accepted: 10/02/2019] [Indexed: 12/31/2022] Open
Abstract
Progressive bone loss is a predominant symptom of aging and osteoporosis. Therefore, the effects of sex steroids (i.e. testosterone and 17β-estradiol) on the differentiation capacity of human bone-derived mesenchymal stromal cells (hMSCs), as progenitors of osteoblasts and adipocytes, are of particular interest. The objectives of the present study were, thus, to elucidate whether bone-derived hMSCs of postmenopausal women produce aromatase (CYP19A1) and, whether they modulate their differentiation behaviour in response to testosterone and 17β-estradiol (E2), in relation to their steroid receptor expression. Supplementation of testosterone resulted in a considerable formation of E2 under osteogenic and adipogenic culture conditions, whereas E2 synthesis remained minimal in the cells cultured in basal medium. Concomitant with high aromatase expression and 17β-estradiol formation of the cells cultured in osteogenic medium supplemented with testosterone, a distinct promotion of late-stage osteogenesis was found, as shown by significant matrix mineralization and a notable increase in osteogenic markers. These effects were abrogated by the aromatase inhibitor anastrozole. Under adipogenic conditions, testosterone reduced the occurrence of lipid droplets and led to a decrease in PPARγ and AR expression, independent of anastrozole. Regardless of the culture conditions, ERα was detectable whilst ERβ was not. In conclusion, aromatase activity is limited to differentiated hMSCs and the resulting 17β-estradiol enhances late osteogenic differentiation stages via ERα. Adipogenic differentiation, on the other hand, is reduced by both sex steroids: testosterone via AR and 17β-estradiol.
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Affiliation(s)
- Kristina Glenske
- Clinic of Small Animals, c/o Institute of Veterinary Anatomy, Histology and Embryology, Justus-Liebig-University of Giessen, Giessen, 35392, Germany
| | - Gerhard Schuler
- Veterinary Clinic of Obstetrics, Gynecology and Andrology, Justus-Liebig-University of Giessen, Giessen, 35392, Germany
| | - Stefan Arnhold
- Institute of Veterinary Anatomy, Histology and Embryology, Justus-Liebig-University of Giessen, Giessen, 35392, Germany
| | - Mohamed I Elashry
- Institute of Veterinary Anatomy, Histology and Embryology, Justus-Liebig-University of Giessen, Giessen, 35392, Germany.,Anatomy and Embryology Department, Faculty of Veterinary Medicine, University of Mansoura, 35516, Egypt
| | - Alena-Svenja Wagner
- Clinic of Small Animals, c/o Institute of Veterinary Anatomy, Histology and Embryology, Justus-Liebig-University of Giessen, Giessen, 35392, Germany
| | - Mike Barbeck
- Department of Oral and Maxillofacial Surgery, Division for Regenerative Orofacial Medicine University Hospital Hamburg-Eppendorf, Hamburg, 20246, Germany
| | - Elena Neumann
- Department of Internal Medicine and Rheumatology, Justus-Liebig-University Giessen, Kerckhoff-Klinik, Bad Nauheim, 61231, Germany
| | - Ulf Müller-Ladner
- Department of Internal Medicine and Rheumatology, Justus-Liebig-University Giessen, Kerckhoff-Klinik, Bad Nauheim, 61231, Germany
| | - Reinhard Schnettler
- Department of Oral and Maxillofacial Surgery, Division for Regenerative Orofacial Medicine University Hospital Hamburg-Eppendorf, Hamburg, 20246, Germany
| | - Sabine Wenisch
- Clinic of Small Animals, c/o Institute of Veterinary Anatomy, Histology and Embryology, Justus-Liebig-University of Giessen, Giessen, 35392, Germany
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4
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Saki F, Kasaee SR, Sadeghian F, Talezadeh P, Ranjbar Omrani GH. The effect of testosterone itself and in combination with letrozole on bone mineral density in male rats. J Bone Miner Metab 2019; 37:668-675. [PMID: 30392074 DOI: 10.1007/s00774-018-0972-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Accepted: 10/16/2018] [Indexed: 01/24/2023]
Abstract
Testosterone is an essential hormone to maintain bone integrity; however, the effect of aromatase enzyme in androgen-induced bone maintenance remains somewhat unclear. The present study evaluated the effect of testosterone itself and combined with letrozole, an aromatase inhibitor, on bone mineral density of male rats. Total of 48 male rats were divided into 4 equal groups (n = 12/group); sham group, O: orchiectomy, O + T: orchiectomized rats treated with testosterone, O + T + L: orchiectomized rats treated with combination of testosterone and letrozole. Bone density (BMD), bone markers, and vitamin D metabolism parameters were checked in all groups before and after the study. There was no significant difference in baseline values of these parameters, but at the end of the study there was a significant decrease in delta BMD at both lumbar and femor in orchiectomized rats in comparison with the sham group (p < 0.001, p < 0.001, respectively). Both testosterone and its combination with letrozole increased lumbar and femoral BMD of orchiectomized rats, with a higher increase in lumbar BMD in O + T group. CTX were higher in O group rats. The present study showed a major role for testosterone on BMD maintenance in male rats. However, testosterone has a potent effect on lumbar BMD, by the aromatization to estradiol.
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Affiliation(s)
- Forough Saki
- Shiraz Endocrinology and Metabolism Research Center, Shiraz University of Medical Sciences, P.O. Box: 71345-1744, Shiraz, Iran
| | - Seyed Reza Kasaee
- Shiraz Endocrinology and Metabolism Research Center, Shiraz University of Medical Sciences, P.O. Box: 71345-1744, Shiraz, Iran
| | - Faezeh Sadeghian
- Shiraz Endocrinology and Metabolism Research Center, Shiraz University of Medical Sciences, P.O. Box: 71345-1744, Shiraz, Iran
| | - Pedram Talezadeh
- Shiraz Endocrinology and Metabolism Research Center, Shiraz University of Medical Sciences, P.O. Box: 71345-1744, Shiraz, Iran
| | - Gholam Hossein Ranjbar Omrani
- Shiraz Endocrinology and Metabolism Research Center, Shiraz University of Medical Sciences, P.O. Box: 71345-1744, Shiraz, Iran.
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5
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Kushwaha P, Ahmad N, Dhar YV, Verma A, Haldar S, Mulani FA, Trivedi PK, Mishra PR, Thulasiram HV, Trivedi R. Estrogen receptor activation in response to Azadirachtin A stimulates osteoblast differentiation and bone formation in mice. J Cell Physiol 2019; 234:23719-23735. [DOI: 10.1002/jcp.28940] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Revised: 05/15/2019] [Accepted: 05/22/2019] [Indexed: 12/23/2022]
Affiliation(s)
| | - Naseer Ahmad
- Endocrinology CSIR‐Central Drug Research Institute Lucknow India
| | - Yogeshwar V. Dhar
- Molecular Biology and Biotechnology CSIR‐National Botanical Research Institute Lucknow India
| | - Ashwni Verma
- Pharmaceutics Division CSIR‐Central Drug Research Institute Lucknow India
| | - Saikat Haldar
- Organic Chemistry Division CSIR‐National Chemical Laboratory Pune India
| | - Fayaj A. Mulani
- Organic Chemistry Division CSIR‐National Chemical Laboratory Pune India
| | - Prabodh K. Trivedi
- Molecular Biology and Biotechnology CSIR‐National Botanical Research Institute Lucknow India
| | - Prabhat R. Mishra
- Pharmaceutics Division CSIR‐Central Drug Research Institute Lucknow India
| | | | - Ritu Trivedi
- Endocrinology CSIR‐Central Drug Research Institute Lucknow India
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6
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Wong SK, Mohamad NV, Jayusman PA, Shuid AN, Ima-Nirwana S, Chin KY. The use of selective estrogen receptor modulators on bone health in men. Aging Male 2019; 22:89-101. [PMID: 29508640 DOI: 10.1080/13685538.2018.1448058] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Selective estrogen receptor modulators (SERMs) represent a class of drugs that act as agonist or antagonist for estrogen receptor in a tissue-specific manner. The SERMs drugs are initially used for the prevention and treatment of osteoporosis in postmenopausal women. Bone health in prostate cancer patients has become a significant concern, whereby patients undergo androgen deprivation therapy is often associated with deleterious effects on bone. Previous preclinical and epidemiological findings showed that estrogens play a dominant role in improving bone health as compared to testosterone in men. Therefore, this evidence-based review aims to assess the available evidence derived from animal and human studies on the effects of SERMs on the male skeletal system. The effects of SERMs on bone mineral density (BMD)/content (BMC), bone histomorphometry, bone turnover, bone strength and fracture risk have been summarized in this review.
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Affiliation(s)
- Sok Kuan Wong
- a Department of Pharmacology, Faculty of Medicine , Universiti Kebangsaan Malaysia , Cheras , Kuala Lumpur , Malaysia
| | - Nur-Vaizura Mohamad
- a Department of Pharmacology, Faculty of Medicine , Universiti Kebangsaan Malaysia , Cheras , Kuala Lumpur , Malaysia
| | - Putri Ayu Jayusman
- a Department of Pharmacology, Faculty of Medicine , Universiti Kebangsaan Malaysia , Cheras , Kuala Lumpur , Malaysia
| | - Ahmad Nazrun Shuid
- a Department of Pharmacology, Faculty of Medicine , Universiti Kebangsaan Malaysia , Cheras , Kuala Lumpur , Malaysia
| | - Soelaiman Ima-Nirwana
- a Department of Pharmacology, Faculty of Medicine , Universiti Kebangsaan Malaysia , Cheras , Kuala Lumpur , Malaysia
| | - Kok-Yong Chin
- a Department of Pharmacology, Faculty of Medicine , Universiti Kebangsaan Malaysia , Cheras , Kuala Lumpur , Malaysia
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7
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Lang-Muritano M, Sproll P, Wyss S, Kolly A, Hürlimann R, Konrad D, Biason-Lauber A. Early-Onset Complete Ovarian Failure and Lack of Puberty in a Woman With Mutated Estrogen Receptor β (ESR2). J Clin Endocrinol Metab 2018; 103:3748-3756. [PMID: 30113650 DOI: 10.1210/jc.2018-00769] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 07/27/2018] [Indexed: 02/04/2023]
Abstract
CONTEXT Estrogen resistance due to mutations in the estrogen receptor α gene (ESR1) has been described in men and women and is characterized by osteoporosis, delayed bone age and continuous growth in adulthood, and delayed puberty and multiple ovarian cysts in women. Although mutations in the estrogen receptor β gene ESR2 were found in 46, XY patients with differences of sex development, no genetic variants of ESR2 were linked to gonadal defects in women. SETTINGS AND PATIENT Here we describe a 16-year-old female patient who came to our tertiary care hospital with complete lack of estrogen action, as demonstrated by absent breast development, primary amenorrhea, and osteoporosis, resembling patients with ESR1 mutation. However, her gonads were clearly abnormal (streak), a finding not observed in ESR1-deficient patients. DESIGN To gain insights into the molecular consequences of the ESR2 defect, whole exome sequencing and extensive functional transactivation studies in ovarian, bone, and breast cells were conducted, with or without the natural activator of estrogen receptors, 17β-estradiol. RESULTS We identified a loss-of-function heterozygous mutation of a highly conserved residue in ESR2 that disrupts estradiol-dependent signaling and has a dominant negative effect, most likely due to failure to interact with its coactivator, nuclear coactivator 1. CONCLUSIONS This is a report of a loss-of-function mutation in the estrogen receptor β in a young woman with complete ovarian failure, suggesting that ESR2 is necessary for human ovarian determination and/or maintenance and that ESR1 is not sufficient to sustain ovarian function in humans.
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Affiliation(s)
- Mariarosaria Lang-Muritano
- Division of Pediatric Endocrinology and Diabetology, University Children's Hospital, Zurich, Switzerland
- Children's Research Center, University Children's Hospital, Zurich, Switzerland
| | - Patrick Sproll
- Division of Endocrinology, University of Fribourg, Fribourg, Switzerland
| | - Sascha Wyss
- Division of Endocrinology, University of Fribourg, Fribourg, Switzerland
| | - Anne Kolly
- Division of Endocrinology, University of Fribourg, Fribourg, Switzerland
| | - Renate Hürlimann
- Division of Pediatric Endocrinology and Diabetology, University Children's Hospital, Zurich, Switzerland
| | - Daniel Konrad
- Division of Pediatric Endocrinology and Diabetology, University Children's Hospital, Zurich, Switzerland
- Children's Research Center, University Children's Hospital, Zurich, Switzerland
| | - Anna Biason-Lauber
- Division of Endocrinology, University of Fribourg, Fribourg, Switzerland
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8
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Kamiński A, Bogacz A, Czerny B. The rs1256044 polymorphism in the ESR2 gene and the risk for osteoporosis in Polish postmenopausal women. Gynecol Endocrinol 2018; 34:579-583. [PMID: 29320918 DOI: 10.1080/09513590.2017.1423465] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
Population association studies have demonstrated a strong association between ESR2 SNPs and BMD, indicating that ESR2 may influence attainment of bone mass. The aim of the study was to investigate the ESR2 gene, located on chromosome 14q linked with BMD, which demonstrates a correlation with changes in bone mass in healthy Caucasian women. The study included 675 unrelated Polish postmenopausal women, including 109 with osteopenia, 333 with osteoporosis and 233 healthy women. The women were classified into the following groups: osteopenia, osteoporosis and normal T-score. Analysis of genotype frequency for the ESR2 rs1256044 polymorphism revealed no statistically significant differences. No statistically significant differences were noted for the allele frequency. However, it is noticeable that the CT genotype occurred more often in women with osteopenia (50.4%, OR = 1.14) and osteoporosis (54.7%, OR = 1.33) than controls (47.7%). There were statistically significant differences between the clinical parameters and distribution of genotypes in patients with osteopenia but not osteoporosis. ESR2 polymorphisms demonstrate minimal influence on BMD changes in women. Identification of various genes with little impact on BMD, such as ESR2, might help design a screening panel for osteoporosis risk assessment in healthy subjects.
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Affiliation(s)
- Adam Kamiński
- a Department of Orthopaedics and Traumatology , Independent Public Clinical Hospital No. 1, Pomeranian Medical University in Szczecin , Szczecin , Poland
| | - Anna Bogacz
- b Department of Stem Cells and Regenerative Medicine , Institute of Natural Fibres and Medicinal Plants , Plewiska , Poland
- c Department of Histocompatibility with Laboratory of Genetic Diagnostics , Regional Blood Center , Poznan , Poland
| | - Bogusław Czerny
- b Department of Stem Cells and Regenerative Medicine , Institute of Natural Fibres and Medicinal Plants , Plewiska , Poland
- d Department of Pharmacology and Pharmacoeconomics , Pomeranian Medical University in Szczecin , Szczecin , Poland
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9
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Koenig A, Buskiewicz I, Huber SA. Age-Associated Changes in Estrogen Receptor Ratios Correlate with Increased Female Susceptibility to Coxsackievirus B3-Induced Myocarditis. Front Immunol 2017; 8:1585. [PMID: 29201031 PMCID: PMC5696718 DOI: 10.3389/fimmu.2017.01585] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 11/03/2017] [Indexed: 01/01/2023] Open
Abstract
Sexual bias is a hallmark in various diseases. This review evaluates sexual dimorphism in clinical and experimental coxsackievirus B3 (CVB3) myocarditis, and how sex bias in the experimental disease changes with increased age. Coxsackieviruses are major causes of viral myocarditis, an inflammation of the heart muscle, which is more frequent and severe in men than women. Young male mice infected with CVB3 develop heart-specific autoimmunity and severe myocarditis. Females infected during estrus (high estradiol) develop T-regulatory cells and when infected during diestrus (low estradiol) develop autoimmunity similar to males. During estrus, protection depends on estrogen receptor alpha (ERα), which promotes type I interferon, activation of natural killer/natural killer T cells and suppressor cell responses. Estrogen receptor beta has opposing effects to ERα and supports pro-inflammatory immunity. However, the sexual dimorphism of the disease is significantly ameliorated in aged animals when old females become as susceptible as males. This correlates to a selective loss of the ERα that is required for immunosuppression. Therefore, sex-associated hormones control susceptibility in the virus-mediated disease, but their impact can alter with the age and physiological stage of the individual.
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Affiliation(s)
- Andreas Koenig
- Department of Pathology, University of Vermont, Burlington, VT, United States
| | - Iwona Buskiewicz
- Department of Pathology, University of Vermont, Burlington, VT, United States
| | - Sally A Huber
- Department of Pathology, University of Vermont, Burlington, VT, United States
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10
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Miki Y, Hata S, Ono K, Suzuki T, Ito K, Kumamoto H, Sasano H. Roles of Aryl Hydrocarbon Receptor in Aromatase-Dependent Cell Proliferation in Human Osteoblasts. Int J Mol Sci 2017; 18:ijms18102159. [PMID: 29039776 PMCID: PMC5666840 DOI: 10.3390/ijms18102159] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 10/13/2017] [Accepted: 10/13/2017] [Indexed: 11/16/2022] Open
Abstract
Aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor and its expression is influenced by environmental compounds, such as 3-methylcholanthrene (3-MC) and β-naphthoflavone (β-NF). AhR and its downstream genes, such as CYP1A1, are considered to play a pivotal role in xenobiotic responses. AhR signaling has also been proposed to mediate osteogenesis in experimental animals, but its details have remained unclear. Therefore, in this study, we examined the possible roles of AhR in human bone. Immunohistochemical analysis revealed that AhR was detected in both osteoblasts and osteoclasts. We then screened AhR-target genes using a microarray analysis in human osteoblastic hFOB cells. Results of microarray and subsequent PCR analysis did reveal that estrogen metabolizing and synthesizing enzymes, such as CYP1B1 and aromatase, were increased by 3-MC in hFOB and osteosarcoma cell line, MG-63. The subsequent antibody cytokine analysis also demonstrated that interleukin-1β and -6 expression was increased by 3-MC and β-NF in hFOB cells and these interleukins were well known to induce aromatase. We then examined the cell proliferation rate of hFOB and MG-63 cells co-treated with 3-MC and testosterone as an aromatase substrate. The status of cell proliferation in both hFOB and MG-63 cells was stimulated by 3-MC and testosterone treatment, which was also inhibited by an estrogen blocker, aromatase inhibitor, or AhR antagonist. These findings indicated that AhR could regulate estrogen synthesis and metabolism in bone tissues through cytokine/aromatase signaling.
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Affiliation(s)
- Yasuhiro Miki
- Department of Disaster Obstetrics and Gynecology, International Research Institute of Disaster Science (IRIDeS), Tohoku University, Sendai, Miyagi 980-8575, Japan.
- Department of Anatomic Pathology, Tohoku University Graduate School of Medicine, Sendai, Miyagi 980-8575, Japan.
- Department of Oral Pathology, Tohoku University Graduate School of Dentistry, Sendai, Miyagi 980-8575, Japan.
| | - Shuko Hata
- Department of Anatomic Pathology, Tohoku University Graduate School of Medicine, Sendai, Miyagi 980-8575, Japan.
| | - Katsuhiko Ono
- Department of Anatomic Pathology, Tohoku University Graduate School of Medicine, Sendai, Miyagi 980-8575, Japan.
| | - Takashi Suzuki
- Department of Pathology and Histotechnology, Tohoku University Graduate School of Medicine, Sendai, Miyagi 980-8575, Japan.
| | - Kiyoshi Ito
- Department of Disaster Obstetrics and Gynecology, International Research Institute of Disaster Science (IRIDeS), Tohoku University, Sendai, Miyagi 980-8575, Japan.
| | - Hiroyuki Kumamoto
- Department of Oral Pathology, Tohoku University Graduate School of Dentistry, Sendai, Miyagi 980-8575, Japan.
| | - Hironobu Sasano
- Department of Anatomic Pathology, Tohoku University Graduate School of Medicine, Sendai, Miyagi 980-8575, Japan.
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11
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Bado I, Gugala Z, Fuqua SAW, Zhang XHF. Estrogen receptors in breast and bone: from virtue of remodeling to vileness of metastasis. Oncogene 2017; 36:4527-4537. [PMID: 28368409 PMCID: PMC5552443 DOI: 10.1038/onc.2017.94] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 02/28/2017] [Accepted: 02/28/2017] [Indexed: 12/11/2022]
Abstract
Bone metastasis is a prominent cause of morbidity and mortality in cancer. High rates of bone colonization in breast cancer, especially in the subtype expressing estrogen receptors (ERs), suggest tissue-specific proclivities for metastatic tumor formation. The mechanisms behind this subtype-specific organ-tropism remains largely elusive. Interestingly, as the major driver of ER+ breast cancer, ERs also have important roles in bone development and homeostasis. Thus, any agents targeting ER will also inevitably affect the microenvironment, which involves the osteoblasts and osteoclasts. Yet, how such microenvironmental effects are integrated with direct therapeutic responses of cancer cells remain poorly understood. Recent findings on ER mutations, especially their enrichment in bone metastasis, raised even more provocative questions on the role of ER in cancer-bone interaction. In this review, we evaluate the importance of ERs in bone metastasis and discuss new avenues of investigation for bone metastasis treatment based on current knowledge.
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Affiliation(s)
- Igor Bado
- Lester and Sue Smith Breast Center, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030
- Dan L. Duncan Cancer Center, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030
- Department of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030
| | - Zbigniew Gugala
- Department of Orthopaedic Surgery and Rehabilitation, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555
| | - Suzanne A. W. Fuqua
- Lester and Sue Smith Breast Center, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030
- Dan L. Duncan Cancer Center, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030
| | - Xiang H.-F. Zhang
- Lester and Sue Smith Breast Center, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030
- Dan L. Duncan Cancer Center, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030
- Department of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030
- McNair Medical Institute, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030
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12
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Abstract
As the world population rises, osteoporotic fracture is an emerging global threat to the well-being of elderly patients. The process of fracture healing by intramembranous ossification or/and endochondral ossification involve many well-orchestrated events including the signaling, recruitment and differentiation of mesenchymal stem cells (MSCs) during the early phase; formation of a hard callus and extracellular matrix, angiogenesis and revascularization during the mid-phase; and finally callus remodeling at the late phase of fracture healing. Through clinical and animal research, many of these factors are shown to be impaired in osteoporotic bone. Animal studies related to post-menopausal estrogen deficient osteoporosis (type I) have shown healing to be prolonged with decreased levels of MSCs and decreased levels of angiogenesis. Moreover, the expression of estrogen receptor (ER) was shown to be delayed in ovariectomy-induced osteoporotic fracture. This might be related to the observed difference in mechanical sensitivity between normal and osteoporotic bones, which requires further experiments to elucidate. In mice fracture models related to senile osteoporosis (type II), it was observed that chondrocyte and osteoblast differentiation were impaired; and that transplantation of juvenile bone marrow would result in enhanced callus formation. Other factors related to angiogenesis and vasculogenesis have also been noted to be impaired in aged models, affecting the degradation of cartilaginous matrixes and vascular invasion; the result is changes in matrix composition and growth factors concentrations that ultimately impairs healing during age-related osteoporosis. Most osteoporotic related fractures occur at metaphyseal sites clinically, and reports have indicated that differences exist between diaphyseal and metaphyseal fractures. An animal model that satisfies three main criteria (metaphyseal region, plate fixation, osteoporosis) is suggested for future research for more comprehensive understanding of the impairment in osteoporotic fractures. Therefore, a metaphyseal fracture or osteotomy that achieves complete discontinuity fixed with metal implants is suggested on ovariectomized aged rodent models.
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Affiliation(s)
- Wing Hoi Cheung
- Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China.
| | - Theodore Miclau
- Department of Orthopaedic Surgery, University of California, San Francisco, Orthopaedic Trauma Institute, University of California, San Francisco/San Francisco General Hospital, San Francisco, CA94110, United States
| | - Simon Kwoon-Ho Chow
- Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Frank F Yang
- Department of Orthopaedic Surgery, University of California, San Francisco, Orthopaedic Trauma Institute, University of California, San Francisco/San Francisco General Hospital, San Francisco, CA94110, United States
| | - Volker Alt
- Department of Trauma Surgery, Giessen University Hospital, Giessen-Marburg, Germany
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Mafi Golchin M, Heidari L, Ghaderian SMH, Akhavan-Niaki H. Osteoporosis: A Silent Disease with Complex Genetic Contribution. J Genet Genomics 2016; 43:49-61. [PMID: 26924688 DOI: 10.1016/j.jgg.2015.12.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 10/30/2015] [Accepted: 12/26/2015] [Indexed: 12/17/2022]
Abstract
Osteoporosis is the most common multifactorial metabolic bone disorder worldwide with a strong genetic component. In this review, the evidence for a genetic contribution to osteoporosis and related phenotypes is summarized alongside with methods used to identify osteoporosis susceptibility genes. The key biological pathways involved in the skeleton and bone development are discussed with a particular focus on master genes clustered in these pathways and their mode of action. Furthermore, the most studied single nucleotide polymorphisms (SNPs) analyzed for their importance as genetic markers of the disease are presented. New data generated by next-generation sequencing in conjunction with extensive meta-analyses should contribute to a better understanding of the genetic basis of osteoporosis and related phenotype variability. These data could be ultimately used for identifying at-risk patients for disease prevention by both controlling environmental factors and providing possible therapeutic targets.
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Affiliation(s)
- Maryam Mafi Golchin
- Department of Genetics, Faculty of Medicine, Babol University of Medical Sciences, Babol 4717647745, Iran
| | - Laleh Heidari
- Department of Medical Genetics, Faculty of Medicine, Shahid Beheshti University of Medical Sciences & Health Services, Tehran 1985717443, Iran
| | - Seyyed Mohammad Hossein Ghaderian
- Department of Medical Genetics, Faculty of Medicine, Shahid Beheshti University of Medical Sciences & Health Services, Tehran 1985717443, Iran
| | - Haleh Akhavan-Niaki
- Department of Genetics, Faculty of Medicine, Babol University of Medical Sciences, Babol 4717647745, Iran.
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14
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Abstract
Osteoporotic fracture is known to have impaired healing capacity and therefore takes longer time to heal, as compared with younger one. The mechanism of impaired osteoporotic fracture healing is multifactorial, where lower responsiveness to mechanical loading is generally believed to be one factor, yet not absolutely confirmed. In recent years, low intensity pulsed ultrasound (LIPUS) is demonstrated to have good efficacy in treating normal fracture healing, as proven by many randomized controlled trials, as well as in vitro and animal evidences. The effects of LIPUS on osteoporotic fracture healing was also validated in an animal study, which revealed that osteoporotic fractured bone of SD rats showed radiologically and biomechanically comparable responses to LIPUS as age-matched normal fracture healing, in terms of callus width, bridging rate, bone volume fraction, and stiffness etc. Gene expression profiling also confirmed that osteoporotic fractured bone responded to LIPUS very well by upregulating Col1 and BMP2 (osteogenesis) at early phase, VEGF (angiogenesis) at middle phase and RANKL (remodeling) at late phase. These confirm that osteoporotic bones respond well to LIPUS as good as normal bone. These findings may be associated with estrogen receptors (ERs), as estrogen depletion is sensed and relayed by ERs and ERs also function as mechano-sensors. A previous study observed a delayed ERs expression pattern in fracture callus of OVX rats, as compared with SHAM rats, which correlated well with the expression pattern of BMP-2 (callus formation-related gene). Hence, the responses of osteoporotic fractured bone to LIPUS may be related to the local ERs expression at fracture callus that needs further experiments to validate.
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15
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Khan K, Pal S, Yadav M, Maurya R, Trivedi AK, Sanyal S, Chattopadhyay N. Prunetin signals via G-protein-coupled receptor, GPR30(GPER1): Stimulation of adenylyl cyclase and cAMP-mediated activation of MAPK signaling induces Runx2 expression in osteoblasts to promote bone regeneration. J Nutr Biochem 2015; 26:1491-501. [PMID: 26345541 DOI: 10.1016/j.jnutbio.2015.07.021] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 07/13/2015] [Accepted: 07/20/2015] [Indexed: 01/26/2023]
Abstract
Prunetin is found in red clover and fruit of Prunus avium (red cherry). The effect of prunetin on osteoblast function, its mode of action and bone regeneration in vivo were investigated. Cultures of primary osteoblasts, osteoblastic cell line and HEK293T cells were used for various in vitro studies. Adult female rats received drill-hole injury at the femur diaphysis to assess the bone regenerative effect of prunetin. Prunetin at 10nM significantly (a) increased proliferation and differentiation of primary cultures of osteoblasts harvested from rats and (b) promoted formation of mineralized nodules by bone marrow stromal/osteoprogenitor cells. At this concentration, prunetin did not activate any of the two nuclear estrogen receptors (α and β). However, prunetin triggered signaling via a G-protein-coupled receptor, GPR30/GPER1, and enhanced cAMP levels in osteoblasts. G15, a selective GPR30 antagonist, abolished prunetin-induced increases in osteoblast proliferation, differentiation and intracellular cAMP. In osteoblasts, prunetin up-regulated runt-related transcription factor 2 (Runx2) protein through cAMP-dependent Erk/MAP kinase activation that ultimately resulted in the up-regulation of GPR30. Administration of prunetin at 0.25mg/kg given to rats stimulated bone regeneration at the site of drill hole and up-regulated Runx2 expression in the fractured callus and the effect was comparable to human parathyroid hormone, the only clinically used osteogenic therapy. We conclude that prunetin promotes osteoinduction in vivo and the mechanism is defined by signaling through GPR30 resulting in the up-regulation of the key osteogenic gene Runx2 that in turn up-regulates GPR30.
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Affiliation(s)
- Kainat Khan
- Division of Endocrinology and Center for Research in Anabolic Skeletal Targets in Health and Illness, Central Drug Research Institute, Council of Scientific and Industrial Research, Lucknow 226021, India
| | - Subhashis Pal
- Division of Endocrinology and Center for Research in Anabolic Skeletal Targets in Health and Illness, Central Drug Research Institute, Council of Scientific and Industrial Research, Lucknow 226021, India
| | - Manisha Yadav
- Division of Biochemistry, Central Drug Research Institute, Council of Scientific and Industrial Research, Lucknow 226021, India
| | - Rakesh Maurya
- Division of Medicinal and Process Chemistry, Central Drug Research Institute, Council of Scientific and Industrial Research, Lucknow 226021, India
| | - Arun Kumar Trivedi
- Division of Biochemistry, Central Drug Research Institute, Council of Scientific and Industrial Research, Lucknow 226021, India
| | - Sabyasachi Sanyal
- Division of Biochemistry, Central Drug Research Institute, Council of Scientific and Industrial Research, Lucknow 226021, India
| | - Naibedya Chattopadhyay
- Division of Endocrinology and Center for Research in Anabolic Skeletal Targets in Health and Illness, Central Drug Research Institute, Council of Scientific and Industrial Research, Lucknow 226021, India.
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16
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El Maataoui A, El Maghraoui A, Biaz A, Elmachtani SI, Dami A, Bouhsain S, Mounach A, Chabraoui L, Ouzzif Z. Relationships between vertebral fractures, sex hormones and vitamin D in Moroccan postmenopausal women: a cross sectional study. BMC WOMENS HEALTH 2015; 15:41. [PMID: 25968889 PMCID: PMC4435629 DOI: 10.1186/s12905-015-0199-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Accepted: 05/05/2015] [Indexed: 11/21/2022]
Abstract
Background Vertebral Fractures (VFs) are associated with bone loss that occurs before menopause but is accelerated at menopause as a result of sex hormone deficiency. To determine the association of sex hormones, bone remodeling markers and vitamin D levels with bone mineral density (BMD) and asymptomatic VFs prevalence using vertebral fracture assessment (VFA) in a cohort of Moroccan menopausal women. Methods This was a cross-sectional study conducted from October 2012 to April 2013 with menopausal women aged 50 years old and over. A total of 207 women who had no previous diagnosis of osteoporosis were enrolled in this cross-sectional study. Women were recruited prospectively from our laboratory department. VFA images and scans of the lumbar spine and proximal femur were obtained using a GE Healthcare Lunar Prodigy densitometer. VFs were defined using a combination of Genant semiquantitative approach and morphometry. Serum levels of estradiol, dehydroepiandrosterone sulfate, Sex hormone binding globulin, vitamin D, Osteocalcin, Crosslaps, intact parathormone were measured by Electrochemiluminescent immunoassay technique. Results Among the 207 women, 18.3 % (n = 38) had densitometric osteoporosis. On VFA, VFs were detected in 134 (62.3 %), including 96 (44.6 %) grade 1 and 38 (17.6 %) grade 2/3. There was no difference in the plasma levels of sex steroids, bone remodeling markers and vitamin D in the group of women with VFs (grade 1 and grade 2/3) and without VFs. The combination of variables that best predicted grade 2/3 VFs included the number of years since menopause and the lumbar spine T-score. Conclusion These data confirm the importance of postmenopausal estrogen and SHBG concentrations in the bone loss and the pathogenesis of osteoporosis in elderly women, but not in the occurrence of the VFs.
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Affiliation(s)
- Aissam El Maataoui
- University Mohamed V Souissi, Faculty of Medicine and Pharmacy, Av. Mohamed Belarbi El Alaoui Rabat Institut, University Mohamed V Souissi, BP 6203, Rabat, Morocco. .,Biochemsitry Department, Military Hospital, Rabat, Morocco.
| | - Abdellah El Maghraoui
- University Mohamed V Souissi, Faculty of Medicine and Pharmacy, Av. Mohamed Belarbi El Alaoui Rabat Institut, University Mohamed V Souissi, BP 6203, Rabat, Morocco. .,Rheumatology Department, Military Hospital, Rabat, Morocco.
| | - Asmae Biaz
- Biochemsitry Department, Military Hospital, Rabat, Morocco.
| | - Samira Idrissi Elmachtani
- University Mohamed V Souissi, Faculty of Medicine and Pharmacy, Av. Mohamed Belarbi El Alaoui Rabat Institut, University Mohamed V Souissi, BP 6203, Rabat, Morocco. .,Biochemsitry Department, Military Hospital, Rabat, Morocco.
| | - Abdellah Dami
- University Mohamed V Souissi, Faculty of Medicine and Pharmacy, Av. Mohamed Belarbi El Alaoui Rabat Institut, University Mohamed V Souissi, BP 6203, Rabat, Morocco. .,Biochemsitry Department, Military Hospital, Rabat, Morocco.
| | - Sanae Bouhsain
- University Mohamed V Souissi, Faculty of Medicine and Pharmacy, Av. Mohamed Belarbi El Alaoui Rabat Institut, University Mohamed V Souissi, BP 6203, Rabat, Morocco. .,Biochemsitry Department, Military Hospital, Rabat, Morocco.
| | - Aziza Mounach
- University Mohamed V Souissi, Faculty of Medicine and Pharmacy, Av. Mohamed Belarbi El Alaoui Rabat Institut, University Mohamed V Souissi, BP 6203, Rabat, Morocco. .,Rheumatology Department, Military Hospital, Rabat, Morocco.
| | - Layachi Chabraoui
- University Mohamed V Souissi, Faculty of Medicine and Pharmacy, Av. Mohamed Belarbi El Alaoui Rabat Institut, University Mohamed V Souissi, BP 6203, Rabat, Morocco. .,Biochemistry Department, Ibn Sina Hospital, Rabat, Morocco.
| | - Zohra Ouzzif
- University Mohamed V Souissi, Faculty of Medicine and Pharmacy, Av. Mohamed Belarbi El Alaoui Rabat Institut, University Mohamed V Souissi, BP 6203, Rabat, Morocco. .,Biochemsitry Department, Military Hospital, Rabat, Morocco.
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Callus formation is related to the expression ratios of estrogen receptors-alpha and -beta in ovariectomy-induced osteoporotic fracture healing. Arch Orthop Trauma Surg 2014; 134:1405-16. [PMID: 25085540 DOI: 10.1007/s00402-014-2070-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2014] [Indexed: 02/09/2023]
Abstract
INTRODUCTION This study characterizes ovariectomized (OVX)-induced osteoporotic fracture healing with focus on estrogen receptors (ERs). Callus formation plays a critical role in fracture healing, and ERs are well-known mechanosensors in osteogenic pathways. It was hypothesized that callus formation was related to and partially determined by the difference in expression patterns of ERs in both normal and OVX-induced osteoporotic fractures. METHODS Closed femoral fracture in SHAM and ovariectomized rats were used in this study. Weekly callus width (CW) and area (CA), endpoint mechanical properties, gene expressions of Col-1, BMP-2, ER-α, ER-β and ER-α:ER-β ratios (ER-ratios), and correlations were assessed at 2, 4 and 8 weeks post-fracture. RESULTS CW and CA results confirmed that OVX-induced osteoporotic fracture was delayed at 2-4 weeks with impaired endpoint mechanical properties. Gene expressions of ER-α and ER-β were higher in the SHAM group at week 2 (p < 0.05) and later lowered at week 8; whereas the OVX group showed an opposing trend. Moderate correlation existed between ER-α and BMP-2 (0.545, p = 0.003), and ER-ratio and BMP-2 (0.601, p = 0.001), and BMP-2 to CW and CA (r = 0.709, p = 0.000 and r = 0.588, p = 0.001, respectively). ER-α and ER-β proteins expressions were confirmed by immunohistochemistry at the fracture callus in reparative progenitor cells, osteoblasts- and osteoclasts-like cells. CONCLUSION We conclude that the delayed healing rate and impaired callus quality in OVX-induced osteoporotic fracture is related to the delayed expression of ERs. A high ER-α:ER-β ratio favors callus formation.
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Sapir-Koren R, Livshits G. Is interaction between age-dependent decline in mechanical stimulation and osteocyte-estrogen receptor levels the culprit for postmenopausal-impaired bone formation? Osteoporos Int 2013; 24:1771-89. [PMID: 23229466 DOI: 10.1007/s00198-012-2208-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Accepted: 10/02/2012] [Indexed: 12/19/2022]
Abstract
Declining estrogen levels during menopause are widely considered to be a major cause of age-dependent bone loss, which is primarily manifested by increased bone resorption by osteoclasts. We present accumulating evidence supporting another aspect of metabolic bone loss, suggesting that the combined interaction between age-dependent factors, namely, estrogen deficiency and reduced day-by-day activity/mechanical stimulation, directly leads to a reduction in anabolic processes. Such decreased bone formation results in diminished bone strength and failure to maintain the load-bearing competence of a healthy skeleton and to postmenopausal osteoporosis disorder. Estrogen receptors (ERs), as mediators of estrogenic actions, are essential components of bone osteocyte and osteoblast mechano-adaptive responses. ER expression appears to be upregulated by adequate circulating estrogen levels. ERα signaling pathways participate in the mechanotransduction response through obligatory "non-genomic" actions that occur independently of estrogen binding to ER and by a potentially "genomic", estrogen-dependent mode. The experimental data indicate that cross talk between the ERα-"non-genomic" and Wnt/β-catenin signaling pathways constitutes the major regulatory mechanism. This interaction uses mechanically and ER-induced prostaglandin E2 as a mediator for the downregulation of osteocyte production of sclerostin. Sclerostin suppression, in turn, is a central prerequisite for load-induced formation and mineralization of the bone matrix. It is therefore plausible that future strategies for preventing and treating postmenopausal osteoporosis may use estrogenic compounds (such as selective estrogen receptor modulators or phytoestrogens) with physical activity, to complement antiresorptive therapy, aimed at stopping further bone loss and possibly even reversing it by stimulation of bone gain.
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Affiliation(s)
- R Sapir-Koren
- Human Population Biology Research Unit, Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv 69978, Israel
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Hiyama S, Sugiyama T, Kusuhara S, Uchida T. Evidence for estrogen receptor expression during medullary bone formation and resorption in estrogen-treated male Japanese quails (Coturnix coturnix japonica). J Vet Sci 2013; 13:223-7. [PMID: 23000578 PMCID: PMC3467396 DOI: 10.4142/jvs.2012.13.3.223] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The temporal expression of estrogen receptor (ER)-α and ER-β mRNA was examined in male Japanese quails. Femurs of quails receiving 17β-estradiol underwent RT-PCR and histochemical analysis 1 to 15 days after treatment. Untreated quails were used as controls (day 0). Between days 0 and 5, cells lining the bone endosteal surface differentiated into osteoblasts, which in turn formed medullary bone. Expression of ER-α was already observed on day 0 and increased slightly during bone formation whereas ER-β was hardly detected throughout this process. After osteoclasts appeared on the medullary bone surface, this type of bone disappeared from the bone marrow cavity (days 7˜15). ER-α expression simultaneously decreased slightly and ER-β levels remained very low. These results suggest that estrogen activity mediated by ER-α not only affects medullary bone formation but also bone resorption.
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Affiliation(s)
- Shinji Hiyama
- Department of Oral Biology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima 734-8553, Japan.
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20
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Lim V, Li J, Gong Y, Yuan JM, Wu TS, Hammond G, Jin A, Koh WP, Yong E. Serum free estradiol and estrogen receptor-α mediated activity are related to decreased incident hip fractures in older women. Bone 2012; 50:1311-6. [PMID: 22445734 PMCID: PMC3353105 DOI: 10.1016/j.bone.2012.03.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Revised: 03/01/2012] [Accepted: 03/07/2012] [Indexed: 10/28/2022]
Abstract
There is paucity of data from Asian women on the association between serum estrogens and osteoporotic hip fracture risk. We conducted a case-control study nested within a population-based prospective cohort, The Singapore Chinese Health Study, to evaluate serum estrogens levels, ERα-mediated estrogenic activity and hip fracture risk in postmenopausal Asian women. Among 35,298 women who were recruited between 1993 and 1998, 15,410 women donated blood for research between 1999 and 2004. From this subcohort, we identified 140 cases who subsequently suffered hip fracture after blood donation, and 278 age-matched controls. Serum levels of total estrone, estradiol and sex hormone binding globulin levels were measured in a blinded fashion among cases and controls. ERα-mediated estrogenic activity of serum samples was quantified using a sensitive ERα-driven cell bioassay. Women with hip fracture had lower serum estrogens than control women. Compared to the lowest quintile, women in the highest quintile of free estradiol exhibited a statistically significant 57% reduction in risk of hip fracture (95% confidence interval (CI), 6-80%), with a dose-dependent relationship (p for trend=0.021). High levels of ERα-mediated estrogenic activity were also associated with decreased risk of hip fracture (p for trend=0.048). Overall, women with relatively high levels of both free estradiol and ERα-mediated estrogenic activity had a 55% reduction in hip fracture risk (95% CI, 17-76%) compared to women with low levels of both. High levels of free estradiol and ERα-mediated estrogen activity in sera were associated with reduced hip fracture risk in Chinese postmenopausal women.
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Affiliation(s)
- Vanessa Lim
- Department of Obstetrics & Gynecology, Yong Loo Lin School of Medicine, National University of Singapore
| | - Jun Li
- Department of Obstetrics & Gynecology, Yong Loo Lin School of Medicine, National University of Singapore
| | - Yinhan Gong
- Department of Obstetrics & Gynecology, Yong Loo Lin School of Medicine, National University of Singapore
| | - Jian-Min Yuan
- Division of Cancer Control and Population Sciences, University of Pittsburgh Cancer Institute, and Department of Epidemiology, University of Pittsburgh Graduate School of Public Health, Pittsburgh, Pennsylvania, USA
| | - Tsung Sheng Wu
- Department of Obstetrics & Gynecology, University of British Columbia, Vancouver, Canada
| | - Geoffrey Hammond
- Department of Obstetrics & Gynecology, University of British Columbia, Vancouver, Canada
| | - Aizhen Jin
- National Registry of Diseases Office, Ministry of Health, Singapore
| | - Woon-Puay Koh
- Saw Swee Hock School of Public Health, National University of Singapore
| | - E.L. Yong
- Department of Obstetrics & Gynecology, Yong Loo Lin School of Medicine, National University of Singapore
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21
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Foryst-Ludwig A, Kintscher U. Metabolic impact of estrogen signalling through ERalpha and ERbeta. J Steroid Biochem Mol Biol 2010; 122:74-81. [PMID: 20599505 DOI: 10.1016/j.jsbmb.2010.06.012] [Citation(s) in RCA: 118] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2009] [Revised: 06/16/2010] [Accepted: 06/21/2010] [Indexed: 02/07/2023]
Abstract
Estrogens, acting on both estrogen receptors alpha (ERalpha) and beta (ERbeta) are recognized as important regulators of glucose homeostasis and lipid metabolism. ERs belong to the family of nuclear hormone receptors which mainly act as ligand activated transcription factors. Both ERs are expressed in metabolic tissue such as adipose tissue, skeletal muscle, liver and pancreas, as well as in the central nervous system. Expression pattern of both ERs differ between species, sexes, and specific tissues. The present review will focus on the key effects of ERs on glucose- and lipid metabolism. It appears that ERalpha mainly mediates beneficial metabolic effects of estrogens such as anti-lipogenesis, improvement of insulin sensitivity and glucose tolerance, and reduction of body weight/fat mass. In contrast, ERbeta activation seems to be detrimental for the maintenance of regular glucose and lipid homeostasis. Metabolic actions of both receptors in relevant tissues will be discussed.
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Affiliation(s)
- Anna Foryst-Ludwig
- Center for Cardiovascular Research (CCR), Institute of Pharmacology, Charité-Universitätsmedizin Berlin, Hessische Str. 3-4, 10115 Berlin, Germany
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Imai Y, Youn MY, Kondoh S, Nakamura T, Kouzmenko A, Matsumoto T, Takada I, Takaoka K, Kato S. Estrogens maintain bone mass by regulating expression of genes controlling function and life span in mature osteoclasts. Ann N Y Acad Sci 2009; 1173 Suppl 1:E31-9. [PMID: 19751412 DOI: 10.1111/j.1749-6632.2009.04954.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Estrogens play a key role in regulation of bone mass and strength by controlling activity of bone-forming osteoblasts and bone-resorbing osteoclasts. Cellular effects of estrogens are mediated predominantly by the action of estrogen receptor alpha (ERalpha). In earlier studies, ablation of the ERalpha gene in mice did not result in osteoporotic phenotypes due to systemic endocrine disturbance and compensatory effects of elevated levels of testosterone. Despite the relatively well-established effects in osteoblasts, little is known about the direct action of estrogen in osteoclasts. Development in the last decade of more sophisticated genetic manipulation approaches opened new possibilities to explore cell-specific roles of nuclear receptors in bone tissue. Recently, we have generated osteoclast-specific ERalpha gene knockout mice and shown that in vivo estrogens directly regulate the life span of mature osteoclasts by inducing the expression of pro-apoptotic Fas ligand (FasL). Inhibitory effects of estrogens on osteoclast function were further studied in vitro. We observed sufficiently detectable ERalpha expression in osteoclasts differentiating from primary bone marrow cells or RAW264 cells, although levels of ERalpha were decreasing during progression of the differentiation into mature osteoclasts. Treatment with estrogens led to reduction in expression of osteoclast-specific genes controlling bone resorption activity. However, estrogens did not affect the size of multinucleated osteoclasts or number of nuclei in a mature osteoclast. In conclusion, in osteoclasts, estrogens function to inhibit bone resorption activity and vitality rather than differentiation.
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Affiliation(s)
- Yuuki Imai
- Department of Orthopedic Surgery, Osaka City University Graduate School of Medicine, Osaka, Japan
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Imai Y, Nakamura T, Matsumoto T, Takaoka K, Kato S. Molecular mechanisms underlying the effects of sex steroids on bone and mineral metabolism. J Bone Miner Metab 2009; 27:127-30. [PMID: 19183837 DOI: 10.1007/s00774-008-0021-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2008] [Accepted: 05/12/2008] [Indexed: 11/28/2022]
Abstract
The multifarious functions of sex steroid receptors include a role as regulatory factors for bone and mineral metabolism in vivo. These functions are more complex than originally assumed. The finding of nuclear receptors in osseous tissue alludes to the existence of novel indirect and direct functions of bone tissue beyond skeletal support, hematopoiesis, and calcium homeostasis. Cell-specific gene targeting approaches are an extremely important technology for future studies that will need to be conducted to fully understand the molecular mechanisms underlying bone formation and metabolism.
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Affiliation(s)
- Yuuki Imai
- Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abenoku, Osaka, Osaka 545-8585, Japan.
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Nott SL, Huang Y, Fluharty BR, Sokolov AM, Huang M, Cox C, Muyan M. Do Estrogen Receptor beta Polymorphisms Play A Role in the Pharmacogenetics of Estrogen Signaling? ACTA ACUST UNITED AC 2008; 6:239-259. [PMID: 19337586 DOI: 10.2174/187569208786733820] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Estrogen hormones play critical roles in the regulation of many tissue functions. The effects of estrogens are primarily mediated by the estrogen receptors (ER) alpha and beta. ERs are ligand-activated transcription factors that regulate a complex array of genomic events that orchestrate cellular growth, differentiation and death. Although many factors contribute to their etiology, estrogens are thought to be the primary agents for the development and/or progression of target tissue malignancies. Many of the current modalities for the treatment of estrogen target tissue malignancies are based on agents with diverse pharmacology that alter or prevent ER functions by acting as estrogen competitors. Although these compounds have been successfully used in clinical settings, the efficacy of treatment shows variability. An increasing body of evidence implicates ERalpha polymorphisms as one of the contributory factors for differential responses to estrogen competitors. This review aims to highlight the recent findings on polymorphisms of the lately identified ERbeta in order to provide a functional perspective with potential pharmacogenomic implications.
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Affiliation(s)
- Stephanie L Nott
- Department of Biochemistry & Biophysics, University of Rochester Medical School, Rochester, NY, 14642, USA
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Wang JT, Guo Y, Yang TL, Xu XH, Dong SS, Li M, Li TQ, Chen Y, Deng HW. Polymorphisms in the estrogen receptor genes are associated with hip fractures in Chinese. Bone 2008; 43:910-4. [PMID: 18678289 DOI: 10.1016/j.bone.2008.07.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2008] [Revised: 07/01/2008] [Accepted: 07/02/2008] [Indexed: 11/21/2022]
Abstract
INTRODUCTION Hip fractures (HF) are a major cause of public health burden with strong genetic determination. However, the true causal genes remain largely unknown. MATERIALS AND METHODS Based on the important biological role of estrogens in bone homeostasis, this study aimed to investigate whether the estrogen receptor genes, ESR1 and ESR2, affect the onset of HF in 700 elderly Chinese subjects (350 with osteoporotic HF and 350 healthy controls). We genotyped 32 SNPs in total and examined their associations both by the single-SNP and haplotype tests. RESULTS We identified two novel SNPs of ESR1, rs3020314 and rs1884051, were significantly associated with HF (rs3020314: P=0.0004, OR=1.66, 95%CI: 1.25-2.18; rs1884051: P=0.0004, OR=1.46, 95%CI: 1.19-1.81). We firstly detected significant association of ESR2 with HF (rs960070: P=0.0070, OR=1.43, 95%CI: 1.10-1.86). Haplotype analyses corroborated our single-SNP results. CONCLUSION Our findings have important implications for understanding the pathology of osteoporotic fractures. Independent replication studies are needed to validate our results and explore the most possible functional variants for molecular studies.
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Affiliation(s)
- Jin-Tang Wang
- Department of Orthopaedics, the First Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an 710061, PR China
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Evidence for the expression of estrogen receptors in osteogenic cells isolated from hen medullary bone. Acta Histochem 2008; 111:501-7. [PMID: 18835015 DOI: 10.1016/j.acthis.2008.06.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2007] [Revised: 06/18/2008] [Accepted: 06/30/2008] [Indexed: 12/30/2022]
Abstract
Medullary bone is a unique tissue in female birds and forms in the cavity of long bones. This bone displays rapid remodeling in response to circulating estrogen levels, suggesting that the osteoblasts in this bone are highly sensitive to estrogen. The present study examined expression of two estrogen receptor (ER) mRNAs in osteogenic cells of medullary bone of white Leghorn hens in vitro. At day 3, isolated cells from the hen medullary bone expressed alkaline phosphatase activity. Using immunocytochemistry, ER protein was demonstrated in the nuclei of these cells. RT-PCR analysis revealed that ER-alpha mRNA was constantly expressed from day 3 to day 15 of culture, while ER-beta mRNA was not detected throughout the culture period. These results indicate that estrogen may act via ER-alpha, but not ER-beta, on osteogenic cells of the avian medullary bone.
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Wiik A, Ekman M, Johansson O, Jansson E, Esbjörnsson M. Expression of both oestrogen receptor alpha and beta in human skeletal muscle tissue. Histochem Cell Biol 2008; 131:181-9. [DOI: 10.1007/s00418-008-0512-x] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/09/2008] [Indexed: 02/06/2023]
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Abstract
Due to their ability to mimic the actions of mammalian estrogens, soy phytoestrogens have been proposed as potential therapeutic agents to aid in preventing postmenopausal bone loss. In vitro, phytoestrogens promote osteoblastogenesis and inhibit osteoclastogenesis. Although a relatively large number of intervention studies have been undertaken in animals and humans, the efficacy of phytoestrogens as bone-protective agents in vivo remains unclear. Differences in the bioactivities of individual phytoestrogens, differences in phytoestrogen metabolism and bioavailability within different study populations, and imprecise reporting of the dose of phytoestrogens administered in intervention studies may have contributed to the disparity in study findings.
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Affiliation(s)
- Raewyn C Poulsen
- Institute of Food Nutrition and Human Health, Massey University, Palmerston North, New Zealand
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Abstract
Longitudinal growth, which is primarily due to chondrocytic activity at the level of the epiphyseal growth plate, is influenced by many hormones and growth factors in an endocrine and paracrine manner. Their influence is even more complex during the accelerated growth period of puberty that accounts for about 20% of final adult height. Although abnormalities of growth during puberty are very common, the underlying mechanisms that govern the beginning and cessation of pubertal growth at the level of the growth plate are poorly understood. Sex steroids play a crucial role in pubertal growth both at the systemic level via the GH/IGF-1 axis and at the local level of the epiphyseal growth plate. In both sexes it is now accepted that oestrogen is the critical hormone in controlling growth plate acceleration and fusion. This paper reviews the mechanisms that influence pubertal growth and the problems that are associated with disorders of gonadal function.
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Affiliation(s)
- R J Perry
- Bone & Endocrine Research Group, Royal Hospital for Sick Children, Glasgow, UK.
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Ozono S, Fujita T, Matsuo M, Todoki K, Ohtomo T, Negishi H, Kawase T. Co-treatment with Basic Fibroblast Growth Factor and 17.BETA.-estradiol in the Presence of Dexamethasone Accelerates Bone Formation by Rat Bone Marrow Stromal Cell Culture. ACTA ACUST UNITED AC 2008; 52:366-74. [DOI: 10.2186/jjps.52.366] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Abstract
In general terms, the recognized alterations in circulating humoral factors (hormones, cytokines, growth factors) that occur in ageing, coupled with innate cellular senescence exaggerated by the slow turnover of many connective tissue cell populations and the age-associated alterations in matrix molecule cross-linking, predispose the elderly to altered connective tissue biology. These changes can be profound, leading to poor mobility, altered ability to withstand cold, weakness and an increased risk of falls, fractures and age-associated 'degenerative' diseases, such as osteoarthritis and osteoporosis. As understanding of the causes of altered connective tissue function with age increases, it is becoming clearer that many of the predisposing factors (growth hormone, cytokines, load/life style) are potential targets for improving quality of life in the elderly.
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Affiliation(s)
- A J Freemont
- Division of Regenerative Medicine, The Medical School, The University of Manchester, Oxford Road, Manchester M13 9PT, UK.
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Association of CA Repeat Polymorphism in Estrogen Receptor β Gene with Postmenopausal Osteoporosis in Chinese. J Genet Genomics 2007; 34:868-76. [DOI: 10.1016/s1673-8527(07)60098-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2007] [Accepted: 06/05/2007] [Indexed: 01/16/2023]
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Armstrong VJ, Muzylak M, Sunters A, Zaman G, Saxon LK, Price JS, Lanyon LE. Wnt/beta-catenin signaling is a component of osteoblastic bone cell early responses to load-bearing and requires estrogen receptor alpha. J Biol Chem 2007; 282:20715-27. [PMID: 17491024 DOI: 10.1074/jbc.m703224200] [Citation(s) in RCA: 220] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The Wnt/beta-catenin pathway has been implicated in bone cell response to their mechanical environment. This response is the origin of the mechanism by which bone cells adjust bone architecture to maintain bone strength. Osteoporosis is the most widespread failure of this mechanism. The degree of osteoporotic bone loss in men and women is related to bio-available estrogen. Here we report that in osteoblastic ROS 17/2.8 cells and primary osteoblast cultures, a single short period of dynamic mechanical strain, as well as the glycogen synthase kinase-3beta (GSK-3beta) inhibitor LiCl, increased nuclear accumulation of activated beta-catenin and stimulated TCF/LEF reporter activity. This effect was blocked by the estrogen receptor (ER) modulators ICI 182,780 and tamoxifen and was absent in primary osteoblast cultures from mice lacking ERalpha. Microarray expression data for 25,000 genes from total RNA extracted from tibiae of wild-type mice within 24 h of being loaded in vivo showed differential gene regulation between loaded and contralateral non-loaded bones of 10 genes established to be involved in the Wnt pathway. Only 2 genes were involved in loaded tibiae from mice lacking ERalpha (ERalpha(-/-)). Together these data suggest that Wnt/beta-catenin signaling contributes to bone cell early responses to mechanical strain and that its effectiveness requires ERalpha. Reduced effectiveness of bone cell responses to bone loading, associated with estrogen-related decline in ERalpha, may contribute to the failure to maintain structurally appropriate bone mass in osteoporosis in both men and women.
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Affiliation(s)
- Victoria J Armstrong
- Department of Veterinary Basic Sciences, The Royal Veterinary College, Royal College Street, London, United Kingdom
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Gennari L, De Paola V, Merlotti D, Martini G, Nuti R. Steroid hormone receptor gene polymorphisms and osteoporosis: a pharmacogenomic review. Expert Opin Pharmacother 2007; 8:537-53. [PMID: 17376011 DOI: 10.1517/14656566.8.5.537] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Osteoporosis is a common skeletal disorder with a strong genetic component. In recent years, significant progress has been made in understanding the genetic basis of osteoporosis. Given the biological significance of signalling through steroid hormone receptors, bone biology and calcium homeostasis, alleles of steroid hormone receptor genes have been postulated to contribute to the well-documented genetic predisposition to osteoporosis; and in different studies, these alleles have been associated with variation in bone mass and fracture risk. Even though results are still conflicting and the molecular mechanisms by which these polymorphisms influence receptor activity remain, in part, to be investigated, an additional important issue is represented by potential pharmacogenomic (the investigation of variations of DNA or RNA characteristics as related to drug response) or pharmacogenetic (the influence of variations of DNA sequence on drug response) implications. In fact, steroid hormone receptors actually mediate the action of several compounds known to positively or negatively affect bone homeostasis, such as vitamin D, estrogen and glucocorticoids. This review analyses major pharmacogenetic studies of polymorphisms in steroid hormone receptor genes.
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Affiliation(s)
- Luigi Gennari
- Department of Internal Medicine, Endocrine-Metabolic Sciences and Biochemistry, University of Siena, Viale Bracci 1, 53100 Siena, Italy.
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Wilkinson FL, Liu Y, Rucka AK, Jeziorska M, Hoyland JA, Heagerty AM, Canfield AE, Alexander MY. Contribution of VCAF-positive cells to neovascularization and calcification in atherosclerotic plaque development. J Pathol 2007; 211:362-9. [PMID: 17154367 PMCID: PMC1868967 DOI: 10.1002/path.2114] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Calcification of the vessel wall is a regulated process with many similarities to osteogenesis. Progenitor cells may play a role in this process. Previously, we identified a novel gene, Vascular Calcification Associated Factor (VCAF), which was shown to be important in pericyte osteogenic differentiation. The aim of this study was to determine the localization and expression pattern of VCAF in human cells and tissues. Immunohistochemical analysis of seven atherosclerotic arteries confirmed VCAF protein expression within calcified lesions. In addition, individual VCAF-positive cells were detected within the intima and adventitia in areas where sporadic 3G5-positive pericytes were localized. Furthermore, VCAF-positive cells were identified in newly formed microvessels in association with CD34-positive/CD146-positive/c-kit-positive cells as well as in intact CD31-positive endothelium in internal mammary arteries. Western blot analysis confirmed the presence of VCAF (18 kD) in protein lysates extracted from human smooth muscle cells, endothelial cells, macrophages, and osteoblasts. In fracture callus samples from three patients, VCAF was detected in osteoblasts and microvessels. This study demonstrates the presence of VCAF in neovessels and raises the possibility that VCAF could be a new marker for vascular progenitor cells involved in a number of differentiation pathways. These data may have implications for the prevention or treatment of vascular disease.
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Affiliation(s)
- FL Wilkinson
- Cardiovascular Research Group, Division of Cardiovascular and Endocrine Sciences, University of Manchester, Manchester, UK
| | - Y Liu
- Cardiovascular Research Group, Division of Cardiovascular and Endocrine Sciences, University of Manchester, Manchester, UK
| | - AK Rucka
- Wellcome Trust Centre for Cell-Matrix Research, University of Manchester, Manchester, UK
| | - M Jeziorska
- Division of Laboratory and Regenerative Medicine, University of Manchester, Manchester, UK
| | - JA Hoyland
- Division of Laboratory and Regenerative Medicine, University of Manchester, Manchester, UK
| | - AM Heagerty
- Cardiovascular Research Group, Division of Cardiovascular and Endocrine Sciences, University of Manchester, Manchester, UK
| | - AE Canfield
- Cardiovascular Research Group, Division of Cardiovascular and Endocrine Sciences, University of Manchester, Manchester, UK
- Wellcome Trust Centre for Cell-Matrix Research, University of Manchester, Manchester, UK
| | - MY Alexander
- Cardiovascular Research Group, Division of Cardiovascular and Endocrine Sciences, University of Manchester, Manchester, UK
- Correspondence to: Dr MY Alexander, University of Manchester, Cardiovascular Research Group, 3.30 Core Technology Facility, 46 Grafton St, Manchester M13 9NT, UK. E-mail:
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Ascenzi P, Bocedi A, Marino M. Structure-function relationship of estrogen receptor alpha and beta: impact on human health. Mol Aspects Med 2006; 27:299-402. [PMID: 16914190 DOI: 10.1016/j.mam.2006.07.001] [Citation(s) in RCA: 361] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
17Beta-estradiol (E2) controls many aspects of human physiology, including development, reproduction and homeostasis, through regulation of the transcriptional activity of its cognate receptors (ERs). The crystal structures of ERs with agonists and antagonists and the use of transgenic animals have revealed much about how hormone binding influences ER conformation(s) and how this conformation(s), in turn, influences the interaction of ERs with co-activators or co-repressors and hence determines ER binding to DNA and cellular outcomes. This information has helped to shed light on the connection between E2 and the development or progression of numerous diseases. Current therapeutic strategy in the treatment of E2-related pathologies relies on the modulation of ER trancriptional activity by anti-estrogens; however, data accumulated during the last five years reveal that ER activities are not only restricted to the nucleus. ERs are very mobile proteins continuously shuttling between protein targets located within various cellular compartments (e.g., membrane, nucleus). This allows E2 to generate different and synergic signal transduction pathways (i.e., non-genomic and genomic) which provide plasticity for cell response to E2. Understanding the structural basis and the molecular mechanisms by which ER transduce E2 signals in target cells will allow to create new pharmacologic therapies aimed at the treatment of a variety of human diseases affecting the cardiovascular system, the reproductive system, the skeletal system, the nervous system, the mammary gland, and many others.
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Affiliation(s)
- Paolo Ascenzi
- Department of Biology, University Roma Tre, Viale Guglielmo Marconi 446, I-00146 Roma, Italy
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Zaman G, Jessop HL, Muzylak M, De Souza RL, Pitsillides AA, Price JS, Lanyon LL. Osteocytes use estrogen receptor alpha to respond to strain but their ERalpha content is regulated by estrogen. J Bone Miner Res 2006; 21:1297-306. [PMID: 16869728 DOI: 10.1359/jbmr.060504] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
UNLABELLED The role of mechanical strain and estrogen status in regulating ERalpha levels in bone cells was studied in female rats. OVX is associated with decreased ERalpha protein expression/osteocyte, whereas habitual strain and artificial loading has only a small but positive effect, except on the ulna's medial surface, where artificial loading stimulates reversal of resorption to formation. INTRODUCTION Osteoporosis is the most widespread failure of bones' ability to match their architectural strength to their habitual load bearing. In men and women, the severity of bone loss is associated with bioavailability of estrogen. This association could result from the estrogen receptor (ER) involvement in bone cells' adaptive response to loading. MATERIALS AND METHODS In vivo semiquantitative analysis of the amount of ERalpha protein per osteocyte was performed in immuno-cytochemically stained sections from control and loaded rat ulna, as well as tibias of ovariectomy (OVX) and sham-operated female rats. In vitro, the effect of exogenous estrogen (10(-8) M) and mechanical strain (3400 microepsilon, 1 Hz, 600 cycles) on the expression of ERalpha mRNA levels was assessed in ROS 17/2.8 cells in monolayers using real-time PCR and ER promoter activity. ERalpha translocation in response to exogenous estrogen and mechanical strain was assessed in both ROS 17/2.8 and MLO-Y4 cells. RESULTS More than 90 percent of tibial osteocytes express ERalpha, the level/osteocyte being higher in cortical than cancellous bone. OVX is associated with decreased ERalpha protein expression/osteocyte, whereas in the ulna habitual strain and that caused by artificial loading had only a small but positive effect, except on the medial surface, where loading stimulates reversal of resorption to formation. In unstimulated osteocytes and osteoblasts in situ, and osteocyte-like and osteoblast-like cells in vitro, ERalpha is predominantly cytoplasmic. In vitro, both strain and estrogen stimulate transient ERalpha translocation to the nucleus and transient changes in ERalpha mRNA. Strain but not estrogen also induces discrete membrane localization of ERalpha. CONCLUSIONS Bone cells' responses to both strain and estrogen involve ERalpha, but only estrogen regulates its cellular concentration. This is consistent with the hypothesis that bone loss associated with estrogen deficiency is a consequence of reduction in ERalpha number/activity associated with lower estrogen concentration reducing the effectiveness of bone cells' anabolic response to strain.
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Affiliation(s)
- Gul Zaman
- Department of Basic Sciences, The Royal Veterinary College, University of London, London, United Kingdom.
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Sørensen MG, Henriksen K, Dziegiel MH, Tankó LB, Karsdal MA. Estrogen Directly Attenuates Human Osteoclastogenesis, But Has No Effect on Resorption by Mature Osteoclasts. DNA Cell Biol 2006; 25:475-83. [PMID: 16907645 DOI: 10.1089/dna.2006.25.475] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Estrogen deficiency arising with the menopause promotes marked acceleration of bone resorption, which can be restored by hormone replacement therapy. The inhibitory effects of estrogen seem to involve indirect cytokine- mediated effects via supporting bone marrow cells, but direct estrogen-receptor mediated effects on the bone-resorbing osteoclasts have also been proposed. Little information is available on whether estrogens modulate human osteoclastogenesis or merely inhibit the functional activity of osteoclasts. To clarify whether estrogens directly modulate osteoclastic activities human CD14+ monocytes were cultured in the presence of M-CSF and RANKL to induce osteoclast differentiation. Addition of 0.1-10 nM 17beta-estradiol to differentiating osteoclasts resulted in a dose-dependent reduction in tartrate resistant acid phosphatase (TRACP) activity reaching 60% at 0.1 nM. In addition, 17beta-estradiol inhibited bone resorption, as measured by the release of the C-terminal crosslinked telopeptide (CTX), by 60% at 0.1 nM, but had no effect on the overall cell viability. In contrast to the results obtained with differentiating osteoclasts, addition of 17beta-estradiol (0.001-10 nM) to mature osteoclasts did not affect bone resorption or TRACP activity. We investigated expression of the estrogen receptors, using immunocytochemistry and Western blotting. We found that ER-alpha is expressed in osteoclast precursors, whereas ER- beta is expressed at all stages, indicating that the inhibitory effect of estrogen on osteoclastogenesis is mediated by ER-alpha for the major part. In conclusion, these results suggest that the in vivo effects of estrogen are mediated by reduction of osteoclastogenesis rather than direct inhibition of the resorptive activity of mature osteoclasts.
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Abstract
Estrogens influence many physiological processes in mammals, including but not limited to reproduction, cardiovascular health, bone integrity, cognition, and behavior. Given this widespread role for estrogen in human physiology, it is not surprising that estrogen is also implicated in the development or progression of numerous diseases, which include but are not limited to various types of cancer (breast, ovarian, colorectal, prostate, endometrial), osteoporosis, neurodegenerative diseases, cardiovascular disease, insulin resistance, lupus erythematosus, endometriosis, and obesity. In many of these diseases, estrogen mediates its effects through the estrogen receptor (ER), which serves as the basis for many therapeutic interventions. This Review will describe diseases in which estrogen, through the ER, plays a role in the development or severity of disease.
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Affiliation(s)
- Bonnie J Deroo
- Receptor Biology Section, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, North Carolina 27709, USA
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McMillan J, Fatehi-Sedeh S, Sylvia VL, Bingham V, Zhong M, Boyan BD, Schwartz Z. Sex-specific regulation of growth plate chondrocytes by estrogen is via multiple MAP kinase signaling pathways. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2006; 1763:381-92. [PMID: 16713447 DOI: 10.1016/j.bbamcr.2006.02.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2005] [Revised: 02/07/2006] [Accepted: 02/27/2006] [Indexed: 10/24/2022]
Abstract
Both male and female rat growth plate cartilage cells possess estrogen receptors (ERs), but 17beta-estradiol (E(2)) activates protein kinase C (PKC) and PKC-dependent biological responses to E(2) only in cells from female animals. PKC signaling can elicit genomic responses via mitogen activated protein kinase (MAPK) and E(2) has been shown to activate ERK MAPK in many cells, suggesting that MAPK may play a role in growth plate chondrocytes as well. We tested if E(2) increases MAPK activity and if so, whether the response is limited to female cells, if it is PKC-dependent, and if the mechanism involves traditional ER pathways. We also determined the contribution of MAPK to the biological response of growth plate chondrocytes and assessed the relative contributions of ERK, p38 and JNK MAPKs. Female rat costochondral cartilage cells were treated with E(2) and MAPK-specific activity determined in cell layer lysates. The mechanism of MAPK activation was determined by treating the cells with E(2) conjugated to bovine serum albumin (E(2)-BSA) to assess if membrane receptors were involved; stereospecificity was determined using 17alpha-estradiol; PKC and phospholipase C (PLC) dependence was determined using specific inhibitors; and the ER agonist diethylstilbestrol, the ER antagonist ICI 182780, and tamoxifen were used to assess the role of traditional ER pathways. E(2) regulation of ERK1/2 MAPK was assessed and the relative roles of ERK1/2, p38 and JNK MAPKs determined using specific inhibitors. E(2) caused a rapid dose-dependent activation of MAPK that was greatest in cells treated for 9 min with 10(-9) M hormone; activity remained elevated for 3 h. E(2)'s effect on MAPK was stereospecific and comparable to that of E(2)-BSA. It was insensitive to DES and ICI 182780, dependent on PKC and PLC, blocked by tamoxifen and it did not require gene transcription or translation. E(2) had no effect on ERK1 or ERK2 mRNA or protein but it caused a rapid phosphorylation of ERK1/2 at 9 min. Inhibition of ERK1/2 and p38 MAPK reduced the stimulatory effects of E(2) on alkaline phosphatase activity and [(35)S]-sulfate incorporation. These results suggest that E(2) regulates MAPK through a sex-specific membrane-mediated mechanism that does not involve cytosolic ERs in a traditional sense and that ERK1/2 and p38 mediate the downstream biological effects of the hormone.
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Affiliation(s)
- J McMillan
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, 315 Ferst Drive NW, Atlanta, 30332, USA
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McCarty MF. Isoflavones made simple - genistein's agonist activity for the beta-type estrogen receptor mediates their health benefits. Med Hypotheses 2006; 66:1093-114. [PMID: 16513288 DOI: 10.1016/j.mehy.2004.11.046] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2004] [Accepted: 11/24/2004] [Indexed: 02/06/2023]
Abstract
Soy isoflavones, the focus of much research and controversy, are often referred to as "weak estrogens". In fact, genistein is a relatively potent agonist for the recently characterized beta isoform of the estrogen receptor (ERbeta). The low nanomolar serum concentrations of unconjugated free genistein achieved with high-nutritional intakes of soy isoflavones are near the binding affinity of genistein for this receptor, but are about an order of magnitude lower than genistein's affinity for the "classical" alpha isoform of the estrogen receptor (ERalpha). Moreover, these concentrations are far too low to inhibit tyrosine kinases or topoisomerase II, in vitro activities of genistein often cited as potential mediators of its physiological effects. The thesis that these physiological effects are in fact mediated by ERbeta activation provides a satisfying rationale for genistein's clinical activities. Hepatocytes do not express ERbeta; this explains why soy isoflavones, unlike oral estrogen, neither modify serum lipids nor provoke the prothrombotic effects associated with increased risk for thromboembolic disorders. The lack of uterotrophic activity of soy isoflavones reflects the fact that ERalpha is the exclusive mediator of estrogen's impact in this regard. Vascular endothelium expresses both ERalpha and ERbeta, each of which has the potential to induce and activate nitric oxide synthase; this may account for the favorable influence of soy isoflavones on endothelial function in postmenopausal women and ovariectomized rats. The ERbeta expressed in osteoblasts may mediate the reported beneficial impact of soy isoflavones on bone metabolism. Suggestive evidence that soy-rich diets decrease prostate cancer risk, accords well with the observation that ERbeta appears to play an antiproliferative role in healthy prostate. In the breast, ERalpha promotes epithelial proliferation, whereas ERbeta has a restraining influence in this regard - consistent with the emerging view that soy isoflavones do not increase breast cancer risk, and possibly may diminish it. Premenopausal women enjoy a relative protection from kidney failure; since ERbeta is an antagonist of TGF-beta signaling in mesangial cells, soy isoflavones may have nephroprotective potential. Estrogen also appears to protect women from left ventricular hypertrophy, and recent evidence suggests that this effect is mediated by ERbeta. In conjunction with reports that isoflavones may have a modestly beneficial impact on menopausal symptoms - perhaps reflecting the presence of ERbeta in the hypothalamus - these considerations suggest that soy isoflavone regimens of sufficient potency may represent a safe and moderately effective alternative to HRT in postmenopausal women. Further clinical research is required to characterize the impact of optimal genistein intakes on endothelial and bone function in men. Studies with ERbeta-knockout mice could be helpful for clarifying whether ERbeta does indeed mediate the chief physiological effects of low nanomolar genistein. S-equol, a bacterial metabolite of daidzein, has an affinity for ERbeta nearly as high as that of genistein; whether this compound contributes meaningfully to the physiological efficacy of soy isoflavones in some individuals is still unclear.
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Reinwald S, Weaver CM. Soy isoflavones and bone health: a double-edged sword? JOURNAL OF NATURAL PRODUCTS 2006; 69:450-9. [PMID: 16562857 DOI: 10.1021/np058104g] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Numerous publications and research studies on isoflavones have prompted a nationwide increase in the consumption of soy-based foods and supplements in the United States. Isoflavones are natural endocrine active compounds generally considered to promote health and prevent or slow the onset of certain chronic diseases such as osteoporosis. The beneficial effects of soy isoflavones on bone may, however, be life-stage specific and dependent on the estrogen receptor number and endogenous hormone milieu. Perimenopausal and early menopausal women may therefore be more receptive to the therapeutic effects of isoflavones on bone loss prior to the diminution of estrogen receptors that occurs in the postmenopausal years, whereas laboratory studies in developmental age range animals have demonstrated the potential for adverse effects following exposure to high levels of soy isoflavones. Clinical studies in developing humans that either support or refute findings in animal studies are lacking. The effects of chronic consumption of high levels of soy isoflavones at each life stage to assess risk-benefit ratios should be a high priority of research.
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Affiliation(s)
- Susan Reinwald
- Department of Food Science, Purdue University, West Lafayette, Indiana 47907-2009, USA
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Mullender MG, Tan SD, Vico L, Alexandre C, Klein-Nulend J. Differences in osteocyte density and bone histomorphometry between men and women and between healthy and osteoporotic subjects. Calcif Tissue Int 2005; 77:291-6. [PMID: 16307389 DOI: 10.1007/s00223-005-0043-6] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2005] [Accepted: 07/25/2005] [Indexed: 01/20/2023]
Abstract
Bone defects related to osteoporosis develop with increasing age and differ between males and females. It is currently thought that the bone remodeling process is supervised by osteocytes in a strain-dependent manner. We have shown an altered response of osteocytes from osteoporotic patients to mechanical loading, and osteocyte density is reduced in osteoporotic patients, which might relate to imperfect bone remodeling, leading to lack of bone mass and strength. Hence, information on osteocyte density will contribute to a better understanding of bone biology in males and females and to the assessment of osteoporosis. Osteocyte density as well as conventional histomorphometric parameters of trabecular bone were determined in cancellous iliac crest bone of healthy postmenopausal women and men and of osteoporotic women and men. Osteocyte density was higher in healthy females than in healthy males and lower in osteoporotic females than in healthy females. Bone mass was reduced in osteoporotic patients, both male and female. In females, trabecular number was reduced, whereas in males, trabecular thickness was reduced and eroded surface was increased. There were no correlations between the parameter groups bone architecture, bone formation, bone resorption, and osteocyte density. These results are consistent with impaired osteoblast function in osteoporotic patients and with a different mechanism of bone loss between men and women, in which osteocyte density might play a role. The reduced osteocyte numbers in female osteoporotic patients might relate to imperfect bone remodeling leading to lack of bone mass and strength.
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Affiliation(s)
- M G Mullender
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam, Universiteit van Amsterdam and Vrije Universiteit, Amsterdam, The Netherlands
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Ichikawa S, Koller DL, Peacock M, Johnson ML, Lai D, Hui SL, Johnston CC, Foroud TM, Econs MJ. Polymorphisms in the estrogen receptor beta (ESR2) gene are associated with bone mineral density in Caucasian men and women. J Clin Endocrinol Metab 2005; 90:5921-7. [PMID: 16118344 PMCID: PMC1948071 DOI: 10.1210/jc.2004-2253] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT A major determinant of osteoporotic fractures is peak bone mineral density (BMD), which is a highly heritable trait. Recently, we identified significant linkage for hip BMD in premenopausal sister pairs at chromosome 14q (LOD score = 3.5), where the estrogen receptor beta gene (ESR2) is located. OBJECTIVE The objective of the study was to determine whether ESR2 polymorphisms are associated with normal BMD variation. DESIGN This was a population-based genetic association study, using 11 single nucleotide polymorphisms (SNPs) distributed across the ESR2 gene. SETTING The study was conducted at an academic research laboratory and medical center. PATIENTS AND OTHER PARTICIPANTS A total of 411 healthy men (aged 18-61 yr) and 1291 healthy premenopausal women (aged 20-50 yr) living in Indiana participated in the study. INTERVENTION(S) There were no interventions. MAIN OUTCOME MEASURE(S) The main outcome measures were SNP genotype distributions and their association with BMD at the femoral neck and lumbar spine. RESULTS Significant association of spine BMD was found with three SNPs in men and one SNP in women (P < or = 0.05). The conditional linkage analysis using the ESR2 haplotypes showed that the ESR2 gene accounts for, at most, 18% of the original linkage. CONCLUSIONS ESR2 polymorphisms are significantly associated with bone mass in both men and women. However, the ESR2 gene is not entirely responsible for our original linkage, and an additional gene(s) in chromosome 14q contributes to the determination of BMD.
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Affiliation(s)
- Shoji Ichikawa
- Department of Medicine, Indiana University School of Medicine, 541 North Clinical Drive, Clinical Building 459, Indianapolis, Indiana 46202-5121, USA
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Hu S, Lu SF, Kaplan JR, Adams MR, Simon NG. ERbeta protein expression in female cynomolgus monkey and CF-1 mouse brain: Western analysis. ACTA ACUST UNITED AC 2005; 64:298-309. [PMID: 15898060 DOI: 10.1002/neu.20139] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In humans and rodents, multiple ERbeta variants with sizes ranging from 477-549 amino acids (aa) have been described. The identification of these variants in target tissues has important implications for estrogen signaling and cellular responsiveness. Western blot analysis using two anti-ERbeta antibodies specific for mammalian ERbeta sequences (PA1-310B and PA1-311) was employed to examine ERbeta protein expression in neural tissues from ovariectomized (OVX) cynomolgus macaques and CF-1 mice as well as to assess potential regulatory effects of acute and extended estradiol (E(2)) treatment. In hypothalamic extracts from both species, a single ERbeta immunoreactive (ERbeta-ir) band was detected at approximately 54 kDa, corresponding to the expected molecular weight for ERbeta477 and/or 485. In cynomolgus females, oral E(2) administration for 16 weeks had no apparent effect on hypothalamic ERbeta protein expression. In mouse, a single injection of E(2) did not change hypothalamic ERbeta protein levels 1.5, 4, 8, 16, or 24 h after injection. Extending the hormonal treatment to 4 or 21 days in OVX female mice also had no effect on the level of hypothalamic ERbeta protein. Additional regional analyses in female mouse brain with PA1-310B antibody showed that a second, 59 kDa ERbeta-ir band was present in cortex, striatum, hippocampus, and amygdala that could represent one or both of the larger ERbeta variants (530 and 549aa). The expression level of the second ERbeta isoform exhibited regional variation, with the strongest immunoreactivity detected in cortex and amygdala. Elucidating the functions of these ERbeta isoforms in the CNS will facilitate our understanding of the tissue- and promoter-specific actions of estrogen.
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Affiliation(s)
- Shan Hu
- Department of Biological Sciences, Lehigh University, Bethlehem, Pennsylvania 18015, USA
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Shearman AM, Karasik D, Gruenthal KM, Demissie S, Cupples LA, Housman DE, Kiel DP. Estrogen receptor beta polymorphisms are associated with bone mass in women and men: the Framingham Study. J Bone Miner Res 2004; 19:773-81. [PMID: 15068501 DOI: 10.1359/jbmr.0301258] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2003] [Revised: 12/17/2003] [Accepted: 12/19/2003] [Indexed: 11/18/2022]
Abstract
UNLABELLED ESR2 is expressed in bone cells, yet few studies have tested its variation for association with BMD, an important determinant of osteoporotic fractures. This was investigated in 723 men and 795 women from the Framingham study. Results show association of variation in this gene with BMD in both women and men. INTRODUCTION Osteoporotic fracture risk is highly dependent on bone density, a quantitative multifactorial trait with a substantial genetic component. In contrast to the growing body of evidence that estrogen receptor alpha (ESR1) plays a role in bone metabolism, few studies have examined the estrogen receptor beta (ESR2) gene for association with BMD. An ESR2 CA repeat polymorphism, D14S1026, was associated with BMD in two small studies, each with <200 women. MATERIALS AND METHODS The objective of this investigation was to assess whether D14S1026 or four other intronic polymorphisms were associated with BMD in 723 men and 795 women (mean age, 60 years) from the offspring cohort of the population-based Framingham Study. BMD was measured at the femur (neck, trochanter, and Ward's area) and the lumbar spine (L(2)-L(4)). RESULTS In both women and men, there was significant association of D14S1026 genotype with measures of femoral but not spinal BMD. In addition, genotypes of two common single nucleotide polymorphisms, rs1256031 and rs1256059, in strong linkage disequilibrium with one another but not with D14S1026, were associated with measures of femoral BMD in men. The rs1256031 genotypes had up to a 4.0% difference in mean femoral BMD. An inferred rs1256031-D14S1026-rs1256059 haplotype C-23CA-T was significantly associated with reduced femoral BMD in women (p = 0.03, 0.003, and 0.01 for neck, trochanter, and Ward's area, respectively). Haplotype-based BMD differences ranged from 3.0% to 4.3%. CONCLUSIONS We have observed significant association of common ESR2 variants with measures of femoral BMD in both men and women.
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Affiliation(s)
- Amanda M Shearman
- Center for Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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Jugdaohsingh R, Tucker KL, Qiao N, Cupples LA, Kiel DP, Powell JJ. Dietary silicon intake is positively associated with bone mineral density in men and premenopausal women of the Framingham Offspring cohort. J Bone Miner Res 2004; 19:297-307. [PMID: 14969400 DOI: 10.1359/jbmr.0301225] [Citation(s) in RCA: 185] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2003] [Revised: 08/11/2003] [Accepted: 09/10/2003] [Indexed: 11/18/2022]
Abstract
UNLABELLED The role of dietary silicon in bone health in humans is not known. In a cross-sectional, population-based study (2847 participants), associations between dietary silicon intake and BMD were investigated. Dietary silicon correlated positively and significantly with BMD at all hip sites in men and premenopausal women, but not in postmenopausal women, suggesting that increased silicon intake is associated with increased cortical BMD in these populations. INTRODUCTION Osteoporosis is a burgeoning health and economic issue. Agents that promote bone formation are widely sought. Animal and cellular data suggest that the orthosilicate anion (i.e., dietary silicon) is involved in bone formation. The intake of silicon (Si, approximately 30 mg/day) is among the highest for trace elements in humans, but its contribution to bone health is not known. MATERIALS AND METHODS In a cross-sectional, population-based study, we examined the association between silicon intake and bone mineral density (BMD) in 1251 men and 1596 pre- and postmenopausal women in the Framingham Offspring cohort (age, 30-87 years) at four hip sites and lumbar spine, adjusting for all potential confounding factors known to influence BMD and nutrient intake. RESULTS Silicon intake correlated positively with adjusted BMD at four hip sites in men and premenopausal women, but not in postmenopausal women. No significant association was observed at the lumbar spine in any group. Categorical analysis by Si intake, or energy-adjusted Si intake, supported these findings, and showed large differences in BMD (up to 10%) between the highest (> 40 mg Si/day) and lowest (< 14 mg Si/day) quintiles of silicon intake. A significant association at the lumbar spine in men was also observed. Further analyses indicated that some of the effects seen for moderate consumption of alcoholic beverages on BMD might be attributed to Si intake. CONCLUSIONS These findings suggest that higher dietary silicon intake in men and younger women may have salutary effects on skeletal health, especially cortical bone health, that has not been previously recognized. Confirmation of these results is being sought in a longitudinal study and by assessment of the influence of silicon intake on bone markers in this cohort.
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Affiliation(s)
- Ravin Jugdaohsingh
- Gastrointestinal Laboratory, The Rayne Institute, St Thomas' Hospital, London, United Kingdom.
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Abstract
The use of dietary phyto-oestrogens as a possible option for the prevention of osteoporosis has raised considerable interest because of the increased concern about the risks associated with the use of hormone-replacement therapy. However, the evidence in support of a bone-sparing effect in post-menopausal women is still not sufficiently convincing. Most studies have been performed on soyabean isoflavones (genistein and daidzein), either in the purified form or as a soyabean-based product or extract. In vitro studies using primary cell cultures or stabilised cell lines indicate that treatment with genistein may lead to a reduction in bone resorption, but effects on bone formation have also been shown. Investigations using animal models have provided convincing evidence of major improvements in bone mass or bone turnover following soyabean feeding. Cross-sectional observations in South-East Asian populations with moderately high intakes of soyabean isoflavones (50 mg/d) have shown that women in the high quartile of intake have higher bone mineral density (BMD) and reduced bone turnover, an effect that has not been shown in populations with low average intakes. Human trials have given an indication of a possible effect on lumbar spine BMD, although they have been either short term (<6 months) or methodologically weak. Unresolved issues are: the optimal dose compatible with safety; the individual differences in response that can be related to diet and genotypes; the duration of exposure. Furthermore, there needs to be an evaluation of the relative biological effects of phyto-oestrogens other than isoflavones (lignans, resorcylic acid lactones, flavanols, coumestans) that are also present in European diets.
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Affiliation(s)
- Francesco Branca
- Istituto Nazionale di Ricerca per gli Alimenti e la Nutrizione, Via Ardeatina 546, 00178 Rome, Italy.
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Abstract
Steroids significantly effect skeletal integrity. For example, bone mass decreases with glucocorticoid excess or with estrogen depletion after menopause. Glucocorticoid suppresses gene expression by an essential skeletal tissue transcription factor, Runx2, in rat osteoblasts. We now report that estrogen enhances Runx2 activity in dose- and estrogen receptor-dependent ways independently of changes in Runx2 levels or its DNA binding potential. Estrogen receptor and Runx2 can be collected by co-immunoprecipitation. By two-hybrid gene expression analysis, high affinity complex formation involves portions of Runx2 outside of its own DNA binding domain and the DNA binding domain of the estrogen receptor. Consistent with this interaction, the stimulatory effect of estrogen on Runx2 activity is lost when the DNA binding domain of the estrogen receptor is eliminated. Unlike the stimulatory effect of estrogen and the inhibitory effect of glucocorticoid, androgen fails to increase Runx2 activity, whereas Runx2 potently suppresses gene expression induced by all three steroids. Finally, estrogen increases gene transcription by the transforming growth factor-beta type I receptor gene promoter, which contains several Runx binding sequences, and enhances Smad dependent gene expression by transforming growth factor-beta in osteoblasts. These results reveal that Runx2 can integrate complex effects on gene transcription in hormone-, growth factor-, and tissue-restricted ways.
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Affiliation(s)
- Thomas L McCarthy
- Department of Surgery, Yale University School of Medicine, New Haven, Connecticut 06520-8041, USA.
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