Androgens and bone

Restrictive Eating Disorders and Skeletal Health in Adolescent Girls and Young Women

This article reviews the effects of restrictive eating disorders on bone health. The relationship between eating disorders and amenorrhea is discussed in detail. The pathologic impact of malnutrition on bone is explored by examining the results of studies using various available imaging techniques. The multiple hormonal alterations seen in adolescents and young women with anorexia nervosa are reviewed, as well as how these alterations may influence bone turnover, density, structure, and strength. The diagnostic clinical evaluation for adolescents and young women with these disorders is also outlined. Available treatment options, including those that hold promise for efficacy, as well as those we deemed to be ineffective, are considered from both the clinical and mechanistic standpoints. Finally, future research opportunities are offered, including intriguing work in the area of fat and bone interactions.

Osteoblast-derived FGF9 regulates skeletal homeostasis

FGF9 has complex and important roles in skeletal development and repair. We have previously observed that Fgf9 expression in osteoblasts (OBs) is regulated by G protein signaling and therefore the present study was done to determine whether OB-derived FGF9 was important in skeletal homeostasis. To directly test this idea, we deleted functional expression of Fgf9 gene in OBs using a 2.3kb collagen type I promoter-driven Cre transgenic mouse line (Fgf9^OB-/-). Both Fgf9 knockout (Fgf9^OB-/-) and the Fgf9 floxed littermates (Fgf9^fl/fl) mice were fully backcrossed and maintained in an FBV/N background. Three month old Fgf9^OB-/- mice displayed a significant decrease in cancellous bone and bone formation in the distal femur and a significant decrease in cortical thickness at the TFJ. Strikingly, female Fgf9^OB-/- mice did not display altered bone mass. Continuous treatment of mouse BMSCs with exogenous FGF9 inhibited mouse BMSC mineralization while acute treatment increased the proliferation of progenitors, an effect requiring the activation of Akt1. Our results suggest that mature OBs are an important source of FGF9, positively regulating skeletal homeostasis in male mice. Osteoblast-derived FGF9 may serve a paracrine role to maintain the osteogenic progenitor cell population through activation of Akt signaling.

Aromatase: Contributions to Physiology and Disease in Women and Men

Aromatase (estrogen synthetase; EC 1.14.14.1) catalyzes the demethylation of androgens' carbon 19, producing phenolic 18-carbon estrogens. Aromatase is most widely known for its roles in reproduction and reproductive system diseases, and as a target for inhibitor therapy in estrogen-sensitive diseases including cancer, endometriosis, and leiomyoma (141, 143). However, all tissues contain estrogen receptor-expressing cells, the majority of genes have a complete or partial estrogen response element that regulates their expression (61), and there are plentiful nonreceptor effects of estrogens (79); therefore, the effect of aromatase through the provision of estrogen is almost universal in terms of health and disease. This review will provide a brief but comprehensive overview of the enzyme, its role in steroidogenesis, the problems that arise with its functional mutations and mishaps, the roles in human physiology of aromatase and its product estrogens, its current clinical roles, and the effects of aromatase inhibitors. While much of the story is that of the consequences of the formation of its product estrogens, we also will address alternative enzymatic roles of aromatase as a demethylase or nonenzymatic actions of this versatile molecule. Although this short review is meant to be thorough, it is by no means exhaustive; rather, it is meant to reflect the cutting-edge, exciting properties and possibilities of this ancient enzyme and its products.

A case series of the safety and efficacy of testosterone replacement therapy in renal failure and kidney transplant patients

Background

Hypogonadism is common in patients with renal dysfunction and does not always correct following transplantation. Recent studies show increased mortality for dialysis and transplant patients with low testosterone (T). These patients are often not treated due to concerns over efficacy and complications (both real and imagined). There is surprisingly scant literature supporting the use of T therapy in these patients. We wished to examine the results of T therapy in our patients with renal failure or following transplant.

Methods

We identified 15 men in our Men’s Health Registry treated with T who either were on dialysis or had a functioning transplant at time of therapy. Demographic, laboratory and clinical outcome data were collected from the electronic medical record.

Results

There were 3 men on dialysis and 12 with a functioning transplant. Mean age was 53.7 years (range, 39–71 years) and mean total serum T was 207.9 ng/mL (range, 45–330 ng/mL). All had bothersome symptoms including fatigue (15/15) and erectile dysfunction (ED) (14/15). Mean hematocrit was 35.8% and 9/15 were anemic. Therapy included patches in 1, topical gels in 6 and testopel pellets in 8. With a mean follow-up of 22.7 months (range, 11–58 months), mean T post therapy was 528 (range, 226–869). Mean hematocrit improved to 42.6% and 7/9 anemic patients improved out of the anemic range. There were no cardiovascular or infectious complications.

Conclusions

Symptomatic hypogonadism is common in dialysis and transplant patients and T replacement therapy can be safely given with improvement in T values and symptoms in most patients. Anemia is usually improved. Testopel pellets can be used in immunosuppressed transplant recipients without infectious complications.

Eurycoma longifolia as a potential alternative to testosterone for the treatment of osteoporosis: Exploring time-mannered proliferative, differentiative and morphogenic modulation in osteoblasts

ETHNOPHARMACOLOGICAL RELEVANCE

Eurycoma longifolia (EL) has been well-studied traditionally as a chief ingredient of many polyherbal formulations for the management of male osteoporosis. It has also been well-recognised to protect against bone calcium loss in orchidectomised rats.

AIM OF THE STUDY

To evaluate the effects of EL on the time-mannered sequential proliferative, differentiative, and morphogenic modulation in osteoblasts compared with testosterone.

MATERIALS AND METHODS

Cell proliferation was analysed using MTS assay and phase contrast microscopy. Osteogenic differentiation of MC3T3-E1 cells was assessed through a series of characteristic assays which include crystal violet staining, alkaline phosphatase (ALP) activity and Van Gieson staining. Taken together, the bone mineralization of extra cellular matrix (ECM) was estimated using alizarin red s (ARS) staining, von kossa staining, scanning electron microscopic (SEM) and energy dispersive x-ray (EDX) analysis.

RESULTS

The cell proliferation data clearly revealed the efficiency of EL particularly at a dose of 25µg/mL, in improving the growth of MC3T3-E1 cells compared with the untreated cells. Data also showed the prominence of EL in significantly promoting ALP activity throughout the entire duration of treatment compared with the testosterone-treated cells. The osteogenic differentiation potential of EL was further explored by analysing mineralization data which revealed that the calcified nodule formation (calcium deposition) and phosphate deposition was more pronounced in cells treated with 25µg/mL concentration of EL at various time points compared with the untreated and testosterone treated cells. The scanning electron microscopic (SEM) analysis also revealed highest globular masses of mineral deposits (identified as white colour crystals) in the ECM of cultured cells treated with 25µg/mL concentration of EL.

CONCLUSION

Compared to testosterone, greater potential of EL in promoting the proliferation and osteogenic differentiation of MC3T3-E1 cells provides an in vitro basis for the prevention of male osteoporosis. Thus, we anticipate that EL can be considered as an alternative approach to testosterone replacement therapy (TRT) for the treatment of male osteoporosis.

Estrogens and Androgens in Skeletal Physiology and Pathophysiology

Estrogens and androgens influence the growth and maintenance of the mammalian skeleton and are responsible for its sexual dimorphism. Estrogen deficiency at menopause or loss of both estrogens and androgens in elderly men contribute to the development of osteoporosis, one of the most common and impactful metabolic diseases of old age. In the last 20 years, basic and clinical research advances, genetic insights from humans and rodents, and newer imaging technologies have changed considerably the landscape of our understanding of bone biology as well as the relationship between sex steroids and the physiology and pathophysiology of bone metabolism. Together with the appreciation of the side effects of estrogen-related therapies on breast cancer and cardiovascular diseases, these advances have also drastically altered the treatment of osteoporosis. In this article, we provide a comprehensive review of the molecular and cellular mechanisms of action of estrogens and androgens on bone, their influences on skeletal homeostasis during growth and adulthood, the pathogenetic mechanisms of the adverse effects of their deficiency on the female and male skeleton, as well as the role of natural and synthetic estrogenic or androgenic compounds in the pharmacotherapy of osteoporosis. We highlight latest advances on the crosstalk between hormonal and mechanical signals, the relevance of the antioxidant properties of estrogens and androgens, the difference of their cellular targets in different bone envelopes, the role of estrogen deficiency in male osteoporosis, and the contribution of estrogen or androgen deficiency to the monomorphic effects of aging on skeletal involution.

Exploratory analysis of the potential relationship between urinary molybdenum and bone mineral density among adult men and women from NHANES 2007-2010

Human exposure to molybdenum (Mo) may play a role in reducing bone mineral density (BMD) by interfering with steroid sex hormone levels. To begin to address gaps in the literature on this topic, the potential relationship between urinary Mo (U-Mo) and BMD at the femoral neck (FN-BMD) and lumbar spine (LS-BMD) was explored in a sample of 1496 adults participating in the 2007-2010 cycles of the National Health and Nutrition Examination Survey. Associations were assessed using multiple linear regression models stratified on sex and age. In adjusted models for 50-80+ year-old women, there was a statistically significant inverse relationship between natural log-U-Mo and LS-BMD (p-value: 0.002), and a statistically significant dose-dependent decrease in LS-BMD with increasing U-Mo quartiles (trend p-value: 0.002). A suggestive (trend p-value: 0.08), dose-dependent decrease in FN-BMD with increasing U-Mo quartiles was noted in this group of women as well. All other adjusted models revealed no statistically significant or suggestive relationships between U-Mo and FN-BMD or LS-BMD. Bone health is important for overall human health and well-being and, given the exploratory nature of this work, additional studies are needed to confirm the results in other populations, and clarify the potential underlying mechanisms of Mo on BMD.

Sex-Related Discordance Between Aortic Valve Calcification and Hemodynamic Severity of Aortic Stenosis: Is Valvular Fibrosis the Explanation?

RATIONALE

Calcific aortic stenosis (AS) is characterized by calcium deposition in valve leaflets. However, women present lower aortic valve calcification loads than men for the same AS hemodynamic severity.

OBJECTIVE

We, thus, aimed to assess sex differences in aortic valve fibrocalcific remodeling.

METHODS AND RESULTS

One hundred and twenty-five patients underwent Doppler echocardiography and multidetector computed tomography within 3 months before aortic valve replacement. Explanted stenotic tricuspid aortic valves were weighed, and fibrosis degree was determined. Sixty-four men and 39 women were frequency matched for age, body mass index, hypertension, renal disease, diabetes mellitus, and AS severity. Mean age (75±9 years), mean gradient (41±18 mm Hg), and indexed aortic valve area (0.41±0.12 cm²/m²) were similar between men and women (all P≥0.18). Median aortic valve calcification (1973 [1124-3490] Agatston units) and mean valve weight (2.36±0.99 g) were lower in women compared with men (both P<0.0001). Aortic valve calcification density correlated better with valve weight in men (r²=0.57; P<0.0001) than in women (r²=0.26; P=0.0008). After adjustment for age, body mass index, aortic valve calcification density, and aortic annulus diameter, female sex was an independent risk factor for higher fibrosis score in AS valves (P=0.003). Picrosirius red staining of explanted valves showed greater amount of collagen fibers (P=0.01), and Masson trichrome staining revealed a greater proportion of dense connective tissue (P=0.02) in women compared with men.

CONCLUSIONS

In this series of patients with tricuspid aortic valve and similar AS severity, women have less valvular calcification but more fibrosis compared with men. These findings suggest that the pathophysiology of AS and thus potential targets for drug development may be different according to sex.

Birth Weight Could Influence Bone Mineral Contents of 10- to 18-Year-Old Korean Adolescents: Results from the Korea National Health and Nutrition Examination Survey (KNHANES) 2010

BACKGROUND

We investigate the relationship between birth weight (BW) and bone mineral content (BMC) in Korean adolescents.

METHODS

Data were obtained from the Korea National Health and Nutrition Examination Survey conducted in 2010. Baseline characteristics were compared according to age- and sex-specific BMC quartiles of total body less head (TBLH), lumbar spine (LS) and femur neck (FN) in 10- to 18-year-old adolescents (male = 474, female = 394).

RESULTS

BW showed a positive correlation with current weight-SDS (p = 0.006 in males, p = 0.008 in females). BW according to TBLH-BMC quartile groups (p for trend <0.003 in males, <0.0001 in females), LS-BMC quartile groups (p for trend <0.034 in males) and FN-BMC quartile groups (p for trend <0.008 in males, <0.020 in females) showed significant differences. The odds ratio (OR) of being in the highest BMC quartile, per 1-kg increase in BW, was significantly increased in TBLH-BMC (OR = 2.14 in males, OR = 3.26 in >16-year-old adolescents) and FN-BMC (OR = 2.62 in males, OR = 3.06 in >16-year-old adolescents) after adjusting for age, height, smoking, drinking, metabolic equivalent of task, and gestational age.

CONCLUSION

BW might be one of the determinant factors of BMC in Korean adolescents.

A concise review of testosterone and bone health

Osteoporosis is a condition causing significant morbidity and mortality in the elderly population worldwide. Age-related testosterone deficiency is the most important factor of bone loss in elderly men. Androgen can influence bone health by binding to androgen receptors directly or to estrogen receptors (ERs) indirectly via aromatization to estrogen. This review summarized the direct and indirect effects of androgens on bone derived from in vitro, in vivo, and human studies. Cellular studies showed that androgen stimulated the proliferation of preosteoblasts and differentiation of osteoblasts. The converted estrogen suppressed osteoclast formation and resorption activity by blocking the receptor activator of nuclear factor k-B ligand pathway. In animal studies, activation of androgen and ERα, but not ERβ, was shown to be important in acquisition and maintenance of bone mass. Human epidemiological studies demonstrated a significant relationship between estrogen and testosterone in bone mineral density and fracture risk, but the relative significance between the two remained debatable. Human experimental studies showed that estrogen was needed in suppressing bone resorption, but both androgen and estrogen were indispensable for bone formation. As a conclusion, maintaining optimal level of androgen is essential in preventing osteoporosis and its complications in elderly men.

"Low Testosterone Levels in Body Fluids Are Associated With Chronic Periodontitis"

There is a debate over the association between low testosterone levels in body fluids and the occurrence of chronic periodontitis (CP). The aim of the present systematic review was to assess whether low testosterone levels in body fluids reflect CP. In order to identify studies relevant to the focus question: “Is there a relationship between low testosterone levels in body fluids and CP?” an electronic search without time or language restrictions was conducted up to June 2016 in indexed databases using different keywords: periodontitis, chronic periodontitis, periodontal diseases, testosterone, and gonadal steroid hormones. A total of eight studies were included in the present systematic review. The number of study participants ranged from 24 to 1,838 male individuals with ages ranging from 15 to 95 years. Seven studies measured testosterone levels in serum, two studies in saliva, and one study in gingiva. Four studies reported a negative association between serum testosterone levels and CP. Two studies reported a positive association between decreased testosterone levels in serum and CP. Increased levels of salivary testosterone among patients with CP were reported in one study; whereas one study reported no significant difference in the concentration of salivary testosterone between patients with and without CP. One study identified significant increase in the metabolism of testosterone in the gingiva of patients with CP. Within the limits of the evidence available, the relationship between low testosterone levels and CP remains debatable and further longitudinal studies and control trials are needed.

Glucocorticoid-Induced Osteoporosis

Glucocorticoids are widely used to treat several diseases; however, one of their major consequences is a deleterious effect on bone that may lead to glucocorticoid-induced osteoporosis. Fractures may begin to occur within 3 months of commencing oral glucocorticoid therapy, and may even occur in patients receiving low doses. The good news is that with effective management, bone loss and fractures can be prevented or greatly reduced in patients receiving glucocorticoids. Despite clear practice guidelines, glucocorticoid-induced osteoporosis often goes undiagnosed and untreated in many patients. In this article, a current overview of glucocorticoid-induced osteoporosis is provided, including how to recognize, prevent and treat osteoporosis in pre- and postmenopausal women receiving glucocorticoid therapy.

Female Mice Lacking Estrogen Receptor-α in Hypothalamic Proopiomelanocortin (POMC) Neurons Display Enhanced Estrogenic Response on Cortical Bone Mass

Estrogens are important regulators of bone mass and their effects are mainly mediated via estrogen receptor (ER)α. Central ERα exerts an inhibitory role on bone mass. ERα is highly expressed in the arcuate (ARC) and the ventromedial (VMN) nuclei in the hypothalamus. To test whether ERα in proopiomelanocortin (POMC) neurons, located in ARC, is involved in the regulation of bone mass, we used mice lacking ERα expression specifically in POMC neurons (POMC-ERα(-/-)). Female POMC-ERα(-/-) and control mice were ovariectomized (OVX) and treated with vehicle or estradiol (0.5 μg/d) for 6 weeks. As expected, estradiol treatment increased the cortical bone thickness in femur, the cortical bone mechanical strength in tibia and the trabecular bone volume fraction in both femur and vertebrae in OVX control mice. Importantly, the estrogenic responses were substantially increased in OVX POMC-ERα(-/-) mice compared with the estrogenic responses in OVX control mice for cortical bone thickness (+126 ± 34%, P < .01) and mechanical strength (+193 ± 38%, P < .01). To test whether ERα in VMN is involved in the regulation of bone mass, ERα was silenced using an adeno-associated viral vector. Silencing of ERα in hypothalamic VMN resulted in unchanged bone mass. In conclusion, mice lacking ERα in POMC neurons display enhanced estrogenic response on cortical bone mass and mechanical strength. We propose that the balance between inhibitory effects of central ERα activity in hypothalamic POMC neurons in ARC and stimulatory peripheral ERα-mediated effects in bone determines cortical bone mass in female mice.

The Current Understanding of Sarcopenia: Emerging Tools and Interventional Possibilities

The purpose of this review is to provide health practitioners and physicians the most current state of the research on sarcopenia, its consequences, and to offer a summary of consensus guidelines for identification based on the most recent and compelling investigations and analyses. To accomplish this, the causes and consequences of sarcopenia will be described, and definitions and screening methods are updated. Importantly, interventional recommendations for sarcopenia will be discussed with a special emphasis on the effects of resistance training on sarcopenia-related outcomes. Furthermore, due to the increasing usage of hormone treatment as a strategy to combat sarcopenia, special consideration on the effects of hormone changes with aging and as interventions will be briefly reviewed.

Ablation of the androgen receptor from vascular smooth muscle cells demonstrates a role for testosterone in vascular calcification

Vascular calcification powerfully predicts mortality and morbidity from cardiovascular disease. Men have a greater risk of cardiovascular disease, compared to women of a similar age. These gender disparities suggest an influence of sex hormones. Testosterone is the primary and most well-recognised androgen in men. Therefore, we addressed the hypothesis that exogenous androgen treatment induces vascular calcification. Immunohistochemical analysis revealed expression of androgen receptor (AR) in the calcified media of human femoral artery tissue and calcified human valves. Furthermore, in vitro studies revealed increased phosphate (Pi)-induced mouse vascular smooth muscle cell (VSMC) calcification following either testosterone or dihydrotestosterone (DHT) treatment for 9 days. Testosterone and DHT treatment increased tissue non-specific alkaline phosphatase (Alpl) mRNA expression. Testosterone-induced calcification was blunted in VSMC-specific AR-ablated (SM-ARKO) VSMCs compared to WT. Consistent with these data, SM-ARKO VSMCs showed a reduction in Osterix mRNA expression. However, intriguingly, a counter-intuitive increase in Alpl was observed. These novel data demonstrate that androgens play a role in inducing vascular calcification through the AR. Androgen signalling may represent a novel potential therapeutic target for clinical intervention.

Low serum testosterone level was associated with extensive coronary artery calcification in elderly male patients with stable coronary artery disease

BACKGROUND

Coronary artery calcification (CAC) is a pandemic condition in elderly patients with coronary artery disease (CAD) and associated with a worse prognosis. Although available data have shown an association between testosterone levels in men and CAD, the association between testosterone and CAC in elderly male patients with CAD remains unknown.

METHODS

A total of 211 consecutive male patients (age ≥ 65 years) who underwent first multidetector computed tomography and following angiography were enrolled from our institution between March 2009 and September 2014. CAD was angiographically documented as significant stenoses (reduction ≥ 50% of the lumen diameter) on any major coronary vessel. The standard Agatston calcium score was calculated. The relationship of serum testosterone level with the CAC score measured by multidetector computed tomography in elderly male patients with stable CAD was evaluated. For data analyses, the CAC score was divided into four categories: ≤ 10, 11-99, 100-399, and ≥ 400, corresponding to minimal, moderate, increased, and extensive calcification.

RESULTS

Patients with higher CAC scores had significantly lower testosterone levels than patients with lower CAC scores (P = 0.048). In logistic regression analysis, testosterone level remained an independent predictor of extensive CAC (odds ratio 0.997, 95% confidence interval 0.994-0.999, P = 0.043).

CONCLUSION

Our findings indicate an inverse association between testosterone level and the susceptibility to extensive CAC in elderly men with stable CAD.

Associations of anthropometric measures on breast cancer risk in pre- and postmenopausal women--a case-control study

Background

The type of silhouette and quantity of fat tissue are correlated with hormonal imbalance which plays a substantial role in breast carcinogenesis. The goal of the study was to investigate the association between various anthropometric characteristics and breast cancer risk.

Methods

Detailed anthropometric assessment was conducted on 487 women of whom 193 had diagnosed breast cancer and were consecutive patients in the Oncology Center, Cracow, Poland between 2002 and 2004. Measurements were divided into four categories: overall body size (body mass index [BMI], waist circumference [WC], waist-hip ratio [WHR]), regional body sizes (skinfold thicknesses, circumferences), thickness of the skeleton (widths, chest diameters), and body proportions. Additionally, results were analyzed in regard to menopausal status. Differences between groups were assessed using Student’s t test and Mann-Whitney’s test. Models of logistic regression for selected data were built to estimate the odds ratio. Results were considered statistically significant when the P value was less than 0.05.

Results

The BMI in both groups was negatively associated with the risk of cancer. Among premenopausal women, WHR increased the risk of breast cancer (WHR > 0.83, OR, 2.72; 95 % CI, 1.01–7.27). Anthropometric indices of hip-to-shoulder ratio in postmenopausal (≥84.2 mm, OR, 0.02; 95 % CI, 0.01–0.11) and trunk-to-height ratio in both premenopausal women (≥32.76, OR, 0.09; 95 % CI, 0.03–0.28) and postmenopausal women (≥32.76, OR, 0.13; 95 % CI, 0.05–0.33) were strongly related to a decreased risk of breast cancer. Thicknesses of the triceps and subscapular skinfolds increased the risk of breast cancer.

Conclusions

Women with breast cancer present with an obese type of silhouette with a specific concentration of fat tissue in the central and upper parts of the body.

Transgender Surgery in Denmark From 1994 to 2015: 20-Year Follow-Up Study

INTRODUCTION

Gender dysphoria is a mismatch between a person's biological sex and gender identity. The best treatment is believed to be hormonal therapy and gender-confirming surgery that will transition the individual toward the desired gender. Treatment in Denmark is covered by public health care, and gender-confirming surgery in Denmark is centralized at a single-center with few specialized plastic surgeons conducting top surgery (mastectomy or breast augmentation) and bottom surgery (vaginoplasty or phalloplasty and metoidioplasty).

AIMS

To report the first nationwide single-center review on transsexual patients in Denmark undergoing gender-confirming surgery performed by a single surgical team and to assess whether age at time of gender-confirming surgery decreased during a 20-year period.

METHODS

Electronic patient databases were used to identify patients diagnosed with gender identity disorders from January 1994 through March 2015. Patients were excluded from the study if they were pseudohermaphrodites or if their gender was not reported.

MAIN OUTCOME MEASURES

Gender distribution, age trends, and surgeries performed for Danish patients who underwent gender-confirming surgery.

RESULTS

One hundred fifty-eight patients referred for gender-confirming surgery were included. Fifty-five cases (35%) were male-to-female (MtF) and 103 (65%) were female-to-male (FtM). In total, 126 gender-confirming surgeries were performed. For FtM cases, top surgery (mastectomy) was conducted in 62 patients and bottom surgery (phalloplasty and metoidioplasty) was conducted in 17 patients. For MtF cases, 45 underwent bottom surgery (vaginoplasty), 2 of whom received breast augmentation. The FtM:MtF ratio of the referred patients was 1.9:1. The median age at the time of surgery decreased from 40 to 27 years during the 20-year period.

CONCLUSION

Gender-confirming surgery was performed on 65 FtM and 40 MtF cases at our hospital, and 21 transsexuals underwent surgery abroad. Mastectomy was performed in 62 FtM and bottom surgery in 17 FtM cases. Vaginoplasty was performed in 45 MtF and breast augmentation in 2 MtF cases. There was a significant decrease in age at the time of gender-confirming surgery during the course of the study period.

Influence of oestrogen deficiency on the development of apical periodontitis

AIM

To evaluate the effects of a long period of oestrogen deficiency on the development of apical periodontitis in rats.

METHODOLOGY

Wistar rats (n = 24), 3 months old, evaluated by vaginal cytology, were included in the study. Twelve animals were ovariectomized (OVX group) and the other 12 were sham operated (control group). One hundred and twenty days after castration, the pulps of the left mandibular first molars were exposed to induce the development of apical periodontitis. Body mass was verified on a weekly basis. Following 21 and 40 days of lesion induction, the animals were sacrificed. Blood was collected for biochemical analysis, and mandibles were removed for radiographic analysis. Comparative analysis of the data was performed by the nonparametric Kruskal-Wallis and Dunn's multiple-comparisons tests. The t-test was applied to compare the oestrogen levels between control and OVX groups.

RESULTS

Radiographs revealed that apical periodontitis lesions were significantly larger in the 40-day OVX group when compared with both 40-day (P < 0.05) and 21-day (P < 0.001) control groups. Serum oestrogen levels were significantly lower in the OVX group (P < 0.01), confirming the efficacy of castration. Oestrogen deficiency resulted in significantly greater body mass gain (P < 0.01) in 40-day OVX group when compared with 40-day control group. Serum concentrations of calcium were similar between groups (P > 0.05). Alkaline phosphatase levels, although higher in the OVX groups (21 and 40 days), were not significantly different.

CONCLUSIONS

Ovariectomized rats had significantly larger apical periodontitis lesions after 40 days of pulp exposure when compared with controls. These findings suggest that bone alterations as a result of long periods of oestrogen deficiency can influence the progression of apical periodontitis.

Osteoblasts promote castration-resistant prostate cancer by altering intratumoral steroidogenesis

The skeleton is the preferred site for prostate cancer (PC) metastasis leading to incurable castration-resistant disease. The increased expression of genes encoding steroidogenic enzymes found in bone metastatic tissue from patients suggests that up-regulated steroidogenesis might contribute to tumor growth at the metastatic site. Because of the overall sclerotic phenotype, we hypothesize that osteoblasts regulate the intratumoral steroidogenesis of castration resistant prostate cancer (CRPC) in bone. We here show that osteoblasts alter the steroidogenic transcription program in CRPC cells, closely mimicking the gene expression pattern described in CRPC. Osteoblast-stimulated LNCaP-19 cells displayed an increased expression of genes encoding for steroidogenic enzymes (CYP11A1, HSD3B1, and AKR1C3), estrogen signaling-related genes (CYP19A1, and ESR2), and genes for DHT-inactivating enzymes (UGT2B7, UGT2B15, and UGT2B17). The observed osteoblast-induced effect was exclusive to osteogenic CRPC cells (LNCaP-19) in contrast to osteolytic PC-3 and androgen-dependent LNCaP cells. The altered steroid enzymatic pattern was specific for the intratibial tumors and verified by immunohistochemistry in tissue specimens from LNCaP-19 xenograft tumors. Additionally, the overall steroidogenic effect was reflected by corresponding levels of progesterone and testosterone in serum from castrated mice with intratibial xenografts. A bi-directional interplay was demonstrated since both proliferation and Esr2 expression of osteoblasts were induced by CRPC cells in steroid-depleted conditions. Together, our results demonstrate that osteoblasts are important mediators of the intratumoral steroidogenesis of CRPC and for castration-resistant growth in bone. Targeting osteoblasts may therefore be important in the development of new therapeutic approaches.

Synthetic androgens as designer supplements

Anabolic androgenic steroids (AAS) are some of the most common performance enhancing drugs (PED) among society. Despite the broad spectrum of adverse effects and legal consequences, AAS are illicitly marketed and distributed in many countries. To circumvent existing laws, the chemical structure of AAS is modified and these designer steroids are sold as nutritional supplements mainly over the Internet. Several side effects are linked with AAS abuse. Only little is known about the pharmacological effects and metabolism of unapproved steroids due to the absence of clinical studies. The large number of designer steroid findings in dietary supplements and the detection of new compounds combined with legal loopholes for their distribution in many countries show that stricter regulations and better information policy are needed.

Effects of hyperprolactinemia on the tibial epiphyseal plate of mice treated with sex hormones

The aim of this study was to evaluate the effects of metoclopramide-induced hyperprolactinemia on the tibial epiphyseal plate of hormone-treated oophorectomized mice. For this purpose, 18 animals with intact ovaries were allocated to two groups, M (metoclopramide) and V (vehicle). One hundred and eight oophorectomized animals were allocated to 12 subgroups: Oophx/V (vehicle); Ooph/M (metoclopramide); Oophx/V + E (vehicle + estradiol); Oophx/M + E (metoclopramide + estradiol); Oophx/V + P (vehicle + progesterone); Oophx/M + P (metoclopramide + progesterone); Oophx/V + T (vehicle + testosterone); Oophx/M + T (metoclopramide + testosterone); Oophx/V + E + P (Vehicle + estradiol + progesterone); Oophx/M + E + P (metoclopramide + estradiol + progesterone); Oophx/V + E + P + T (vehicle + estradiol + progesterone + testosterone); Oophx/M + E + P + T (metoclopramide + estradiol + progesterone + testosterone). After a 50-day treatment was performed histomorphometric and immunohistochemical cell death analysis. In the epiphyseal plate of the hyperprolactinemic and/or oophorectomized animals, cell proliferation and bone formation decreased, inducing intensified cell death. In the sex steroid-treated animals, estrogen boosted cell proliferation; progesterone, bone formation and testosterone, both cell proliferation and bone formation. These findings suggest that oophorectomy and hyperprolactinemia changed epiphyseal plate morphology causing cartilage degeneration. Treatment with combined sex steroids may diminish such deleterious effects.

Sex hormone levels as determinants of bone mineral density and osteoporosis in Vietnamese women and men

This study sought to investigate the prevalence of osteoporosis and the role of sex hormone levels in the determination of bone mineral density (BMD) and osteoporosis in a Vietnamese population of women and men. The cross-sectional study involved 269 women and 222 men aged 13-83 years, who were randomly selected from urban and rural areas in northern Vietnam. Serum concentrations of estradiol and testosterone were analyzed, and BMD was measured by dual X-ray absorptiometry. We found that the prevalence of osteoporosis in postmenopausal women was 18, 17, and 37 % for the femoral neck, total hip, and lumbar spine, respectively. For men aged 50 years or older, the corresponding values were 8, 7, and 12 %. In men, the most important predictors of BMD for the femoral neck and total hip were age, body mass index, and serum levels of estradiol. For the BMD of the lumbar spine, testosterone also had a significant influence. Determinants of osteoporosis in men for the total hip and lumbar spine were age, weight, and serum concentrations of estradiol and testosterone. In postmenopausal women, age, weight, and residence (urban vs rural) were the most important predictors of BMD and osteoporosis. For all women (including those of reproductive age), serum levels of estradiol were also significant. These data suggest that the prevalence of osteoporosis in the Vietnamese population is high also in men, and that estradiol levels are essential for bone mass in both men and women. The results should have clinical implications and increase awareness of an important health issue within Vietnamese society.

Influence of sex steroids on inflammation and bone metabolism

Sex steroids are central to sexual development and reproduction, exerting pleiotropic effects on multiple tissues and organs throughout the lifespan of humans. Sex steroids are fundamental to skeletal development, bone homeostasis and immune function. The composite effect of sex-specific genetic architecture and circulating levels of sex-steroid hormones closely parallels differences in the immune response and may account for corresponding sex-related differences in risk for chronic periodontitis, with men exhibiting greater susceptibility than women. Age-associated reductions in sex steroids also provide insight into apparent temporal increases in susceptibility to periodontitis and alveolar bone loss, particularly among women. Chronic infection and inflammatory conditions, such as periodontal disease, provide a unique platform for exploring the interface of sex steroids, immunity and bone metabolism.

Bone involvement in males with Kallmann disease

BACKGROUND

Kallmann syndrome (KS) is a rare genetic condition characterized by congenital early-onset hypogonadotropic hypogonadism and anosmia or hyposmia. Male subjects are more frequently affected and present absent/delayed puberty, low testosterone levels with higher risk for osteoporosis. Therefore, to maintain normal levels of sex steroids and prevent bone loss, male KS needs life-long hormonal replacement therapy (HRT).

AIMS

The objective of our study is to assess bone involvement in subjects with KS currently treated with HRT.

METHODS

In our retrospective study, we analyzed data from medical records of patients with KS treated with HRT (either gonadotropins or testosterone preparations), including clinical history, biochemical parameters, and the following outcome measures: the bone mineral density (BMD) at the lumbar spine (LS), femoral neck (FN), and total body less head (TBLH); and the Vertebral Fracture Assessment (VFA) by Dual Energy X-ray Absorptiometry (DXA).

RESULTS

Clinical and instrumental data of 32 patients with KS were evaluated; their mean age was 30.32 (± 10.09) years, their mean body mass index (BMI) was 25.71 (± 3.23) kg/m(2). Four patients (12.5%) had a LS BMD Z score below the expected range for age. Five patients had vertebral deformities observed at VFA. Duration of HRT was related to bone health parameters: BMD at all measured sites were higher in patients receiving adequate HRT for more than 2 years compared with the patients treated for less than 6 months. A deficient vitamin D status was found in 43% of cases and it was prevalent in patients with shorter HRT.

DISCUSSION AND CONCLUSION

Early starting and adequate duration of HRT are related to bone health parameters in patients with congenital hypogonadotropic hypogonadism due to KS. Restoring vitamin D sufficiency might also be advisable in this condition.

Doping with anabolic androgenic steroids (AAS): Adverse effects on non-reproductive organs and functions

Since the 1970s anabolic androgenic steroids (AAS) have been abused at ever increasing rates in competitive athletics, in recreational sports and in bodybuilding. Exceedingly high doses are often consumed over long periods, in particular by bodybuilders, causing acute or chronic adverse side effects frequently complicated by additional polypharmacy. This review summarizes side effects on non-reproductive organs and functions; effects on male and female reproduction have been recently reviewed in a parallel paper. Among the most striking AAS side effects are increases in haematocrit and coagulation causing thromboembolism, intracardiac thrombosis and stroke as well as other cardiac disturbances including arrhythmias, cardiomyopathies and possibly sudden death. 17α-alkylated AAS are liver toxic leading to cholestasis, peliosis, adenomas and carcinomas. Hyperbilirubinaemia can cause cholemic nephrosis and kidney failure. AAS abuse may induce exaggerated self-confidence, reckless behavior, aggressiveness and psychotic symptoms. AAS withdrawal may be accompanied by depression and suicidal intentions. Since AAS abuse is not or only reluctantly admitted physicians should be aware of the multitude of serious side effects when confronted with unclear symptoms.

Role of gender in burn-induced heterotopic ossification and mesenchymal cell osteogenic differentiation

BACKGROUND

Heterotopic ossification most commonly occurs after burn injury, joint arthroplasty, and trauma. Male gender has been identified as a risk factor for the development of heterotopic ossification. It remains unclear why adult male patients are more predisposed to this pathologic condition than adult female patients. In this study, the authors use their validated tenotomy/burn model to explore differences in heterotopic ossification between male and female mice.

METHODS

The authors used their Achilles tenotomy and burn model to evaluate the osteogenic potential of mesenchymal stem cells of male and female injured and noninjured mice. Groups consisted of injured male (n = 3), injured female (n = 3), noninjured male (n = 3), and noninjured female (n = 3) mice. The osteogenic potential of cells harvested from each group was assessed through RNA and protein levels and quantified using micro-computed tomographic scan. Histomorphometry was used to verify micro-computed tomographic findings, and immunohistochemistry was used to assess osteogenic signaling at the site of heterotopic ossification.

RESULTS

Mesenchymal stem cells of male mice demonstrated greater osteogenic gene and protein expression than those of female mice (p < 0.05). Male mice in the burn group formed 35 percent more bone than female mice in the burn group. This bone formation correlated with increased pSmad and insulin-like growth factor 1 signaling at the heterotopic ossification site in male mice.

CONCLUSIONS

The authors demonstrate that male mice form quantitatively more bone compared with female mice using their burn/tenotomy model. These findings can be explained at least in part by differences in bone morphogenetic protein and insulin-like growth factor 1 signaling.

Biology of Bone Tissue: Structure, Function, and Factors That Influence Bone Cells

Bone tissue is continuously remodeled through the concerted actions of bone cells, which include bone resorption by osteoclasts and bone formation by osteoblasts, whereas osteocytes act as mechanosensors and orchestrators of the bone remodeling process. This process is under the control of local (e.g., growth factors and cytokines) and systemic (e.g., calcitonin and estrogens) factors that all together contribute for bone homeostasis. An imbalance between bone resorption and formation can result in bone diseases including osteoporosis. Recently, it has been recognized that, during bone remodeling, there are an intricate communication among bone cells. For instance, the coupling from bone resorption to bone formation is achieved by interaction between osteoclasts and osteoblasts. Moreover, osteocytes produce factors that influence osteoblast and osteoclast activities, whereas osteocyte apoptosis is followed by osteoclastic bone resorption. The increasing knowledge about the structure and functions of bone cells contributed to a better understanding of bone biology. It has been suggested that there is a complex communication between bone cells and other organs, indicating the dynamic nature of bone tissue. In this review, we discuss the current data about the structure and functions of bone cells and the factors that influence bone remodeling.

Searching for additional endocrine functions of the skeleton: genetic approaches and implications for therapeutics

Our knowledge of whole organism physiology has greatly advanced in the past decades through mouse genetics. In particular, genetic studies have revealed that most organs interact with one another through hormones in order to maintain normal physiological functions and the homeostasis of the entire organism. Remarkably, through these studies many unexpected novel endocrine means to regulate physiological functions have been uncovered. The skeletal system is one example. In this article, we review a series of studies that over the years have identified bone as an endocrine organ. The mechanism of action, pathological relevance, and therapeutic implications of the functions of the bone-derived hormone osteocalcin are discussed. In the last part of this review we discuss the possibility that additional endocrine functions of the skeleton may exist.

Equol, a Metabolite of Daidzein, Is More Efficient than Daidzein for Bone Formation in Growing Female Rats

Few studies have examined the effects of isoflavones and particularly equol, a metabolite of the isoflavone daidzein, on bone formation during the growth period in animals. The present study investigated the effects of orally administered daidzein or equol on bone formation and bone mineral density in growing female rats. Female Sprague-Dawley rats, aged 3 weeks, were divided into four groups (n = 8 per group) as follows: rats were orally administered a corn oil, 8 mg/day of daidzein, 4 mg/day of equol or 8 mg/day of equol in corn oil for 4 weeks. Daidzein and equol increased the bone mineral density of growing female rats by stimulating bone formation without exhibiting a substantial effect on the weight of their reproductive organs. Bone growth caused by increased bone mineralizing surface and bone formation rate in rats administered with equol was approximately twice that of rats administered with daidzein. These results suggest that equol might be more efficient than daidzein for bone formation in growing female rats. Copyright © 2015 John Wiley & Sons, Ltd.

Importance of bone assessment and prevention of osteoporotic fracture in patients with prostate cancer in the gonadotropic hormone analogues use

The antiandrogenic therapy (ADT) for prostate cancer represents an additional risk factor for the development of osteoporosis and fragility fractures. Still, bone health of patients on ADT is often not evaluated. After literature research we found that simple preventive measures can prevent bone loss in these patients, resulting in more cost-effective solutions to the public health system and family when compared to the treatment of fractures.

Osteocalcin and the pituitary-gonadal axis in older men: a population-based study

OBJECTIVE

Osteocalcin is a well-known marker of bone formation. Recently, mice lacking osteocalcin or its receptor were reported to be subfertile with low testosterone and high luteinizing hormone concentrations. In parallel, in humans, a loss-of-function mutation of the osteocalcin receptor was associated with hypergonadotropic hypogonadism. This suggests that osteocalcin is necessary for normal pituitary-gonadal axis function. Our objective was to determine the association between physiological variations in osteocalcin and the pituitary-gonadal axis in older men.

DESIGN AND PATIENTS

Data were used from the Longitudinal Aging Study Amsterdam (LASA), an ongoing cohort study in a representative sample of the older Dutch population (65-88 years).

MEASUREMENTS

Serum levels of total (T), free (FT) and bioavailable (bioT) testosterone, luteinizing hormone (LH) and osteocalcin were determined. Data were analysed using linear regression analyses and adjusted for age, BMI, 25-hydroxyvitamin D, parathyroid hormone and vitamin K antagonist use.

RESULTS

A total of 614 men participated in the study. The median age was 75·4 (69·8-81·2) years, and the median osteocalcin level was 1·8 (1·3-2·4) nmol/l. Serum osteocalcin was inversely associated with FT (adjusted B = -0·22 ± 0·09 ng/dl, P = 0·012) and bioT (adjusted B = -0·26 ± 0·08 nmol/l, P < 0·01), but not with total T. Furthermore, osteocalcin was positively associated with LH (adjusted B = 0·09 ± 0·03 U/l, P < 0·01).

CONCLUSIONS

Serum osteocalcin was negatively associated with free and bioavailable testosterone and positively with luteinizing hormone levels.

Androgen receptor action in osteoblasts in male mice is dependent on their stage of maturation

Androgen action via the androgen receptor (AR) is essential for normal skeletal growth and bone maintenance post-puberty in males; however, the molecular and cellular mechanisms by which androgens exert their actions in osteoblasts remains relatively unexplored in vivo. To identify autonomous AR actions in osteoblasts independent of AR signaling in other tissues, we compared the extent to which the bone phenotype of the Global-ARKO mouse was restored by replacing the AR in osteoblasts commencing at either the (1) proliferative or (2) mineralization stage of their maturation. In trabecular bone, androgens stimulated trabecular bone accrual during growth via the AR in proliferating osteoblasts and maintained trabecular bone post-puberty via the AR in mineralizing osteoblasts, with its predominant action being to inhibit bone resorption by decreasing the ratio of receptor activator of NF-κB ligand (RANKL) to osteoprotegerin (OPG) gene expression. During growth, replacement of the AR in proliferating but not mineralizing osteoblasts of Global-ARKOs was able to partially restore periosteal circumference, supporting the concept that androgen action in cortical bone to increase bone size during growth is mediated via the AR in proliferating osteoblasts. This study provides further significant insight into the mechanism of androgen action via the AR in osteoblasts, demonstrating that it is dependent on the stage of osteoblast maturation.

Alcohol abuse: critical pathophysiological processes and contribution to disease burden

Alcohol abuse; the most common and costly form of drug abuse, is a major contributing factor to many disease categories. The alcohol-attributable disease burden is closely related to the average volume of alcohol consumption, with dose-dependent relationships between amount and duration of alcohol consumption and the incidence of diabetes mellitus, hypertension, cardiovascular disease, stroke, and pneumonia. The frequent occurrence of alcohol use disorders in the adult population and the significant and widespread detrimental organ system effects highlight the importance of recognizing and further investigating the pathophysiological mechanisms underlying alcohol-induced tissue and organ injury.

Effect of a single injection of testosterone enanthate on 17β estradiol and bone turnover markers in hypogonadal male patients

PURPOSE

Several clinical studies testify the critical role played by estrogens in male bone metabolism. The aim of our study is to assess the effect of a single injection of testosterone enanthate in a group of hypogonadal men on 17β estradiol serum levels and some bone metabolic parameters.

METHOD

Twenty-one hypogonadal males were given one testosterone enanthate injection (250 mg). Blood samples were drawn before the injection and after 1, 2 and 3 weeks. The following variables were measured: Total testosterone (TT), 17β estradiol (17β E2), Sex hormone binding globulin, total alkaline phosphatase, osteocalcin, and C-telopeptide of type I collagen (CTx).

RESULTS

After testosterone injection, both TT and 17β E2 increased, peaking 1 week after the injection. Individual observation of the response of 17β E2 to testosterone showed that a subgroup (n = 9) failed to respond with any increase in 17β E2 at any of the weekly tests (group E2-), while the remainder (n = 12) showed a significant increase in 17β E2, which reached a mean value three times higher than at baseline (group E2+). The E2- patients reached a TT peak lower than that observed in the E+ group. CTx serum levels declined progressively in the E2+ group, reaching the significance (p = 0.03) at the end of the study, while it did not change in E- group.

CONCLUSION

This study suggests that a single injection of testosterone might have different effects on the production of endogenous estrogens, and a significant reduction of bone resorption parameters takes place only in the patients who show a significant increase of 17ß estradiol in response to testosterone administration.

Orchidectomy-induced alterations in volumetric bone density, cortical porosity and strength of femur are attenuated by dietary conjugated linoleic acid in aged guinea pigs

Age-related osteoporosis and sarcopenia are ascribed in part to reductions in anabolic hormones. Dietary conjugated linoleic acid (CLA) improves lean and bone mass, but its impact during androgen deficiency is not known. This study tested if CLA would attenuate the effects of orchidectomy (ORX)-induced losses of bone and lean tissue. Male guinea pigs (n=40; 70-72 weeks), were randomized into four groups: (1) SHAM+Control diet, (2) SHAM+CLA diet, (3) ORX+Control diet, (4) ORX+CLA diet. Baseline blood sampling and dual-energy X-ray absorptiometry (DXA) scans were conducted, followed by surgery 4 days later with the test diets started 7 days after baseline sampling. Serial blood sampling and DXA scans were repeated 2, 4, 8 and 16 weeks on the test diets. Body composition and areal BMD (aBMD) of whole body, lumbar spine, femur and tibia were measured using DXA. At week 16, muscle protein fractional synthesis rate (FSR), volumetric BMD (vBMD), microarchitecture and bone strength were assessed. Body weight declined after SHAM and ORX surgery, with slower recovery in the ORX group. Dietary CLA did not affect weight or lean mass, but attenuated gains in fat mass. Lean mass was stable in SHAM and reduced in ORX by 2 weeks with whole body and femur bone mineral content (BMC) reduced by 4 weeks; CLA did not alter BMC. By week 16 ORX groups had lower free testosterone and myofibrillar FSR, yet higher cortisol, osteocalcin and ionized calcium with no alterations due to CLA. ORX+Control had higher prostaglandin E2 (PGE2) and total alkaline phosphatase compared to SHAM+Control whereas ORX+CLA were not different from SHAM groups. Femur metaphyseal vBMD was reduced in ORX+CTRL with the reduction attenuated by CLA. Femur cortical thickness (Ct.Th.) and biomechanical strength were reduced and cortical porosity (Ct.Po.) elevated by ORX and attenuated by CLA. This androgen deficient model with a sarcopenic-osteoporotic phenotype similar to aging men responded to dietary CLA with significant benefits to femur density and strength.

The unsolved case of "bone-impairing analgesics": the endocrine effects of opioids on bone metabolism

The current literature describes the possible risks for bone fracture in chronic analgesics users. There are three main hypotheses that could explain the increased risk of fracture associated with central analgesics, such as opioids: 1) the increased risk of falls caused by central nervous system effects, including sedation and dizziness; 2) reduced bone mass density caused by the direct opioid effect on osteoblasts; and 3) chronic opioid-induced hypogonadism. The impact of opioids varies by sex and among the type of opioid used (less, for example, for tapentadol and buprenorphine). Opioid-associated androgen deficiency is correlated with an increased risk of osteoporosis; thus, despite that standards have not been established for monitoring and treating opioid-induced hypogonadism or hypoadrenalism, all patients chronically taking opioids (particularly at doses ≥100 mg morphine daily) should be monitored for the early detection of hormonal impairment and low bone mass density.

Participation of sex hormones in multifactorial pathogenesis of adolescent idiopathic scoliosis

PURPOSE

In order to verify the potential association between the aetiopathogenesis of adolescent idiopathic scoliosis (AIS) and the process of sexual maturation, we determined the concentrations of oestrogens in pre- and postmenarcheal girls affected by this condition. AIS, occurring mostly in pubescent girls, is one of the most frequent forms of faulty posture. Therefore, it was assumed that the multifactorial pathomechanism of AIS involves significant deficiency of oestrogens.

METHODS

The diagnosis of AIS was established on the basis of physical examination and analyses of radiograms. Concentrations of FSH, LH, oestrogens, progesterone, osteocalcin and RANKL were determined by ELISA. The activity of alkaline phosphatase (AP) was measured by kinetic method. The study included pre- and postmenarcheal girls with AIS and corresponding groups of scoliosis-free controls.

RESULTS

In premenarcheal scoliotic girls, the levels of FSH, LH and oestradiol were lower; the levels of progesterone, oestrone and oestriol were higher; and the concentrations of oestrone and oestriol were similar compared to premenarcheal controls. Higher levels of RANKL, osteocalcin and AP were observed in premenarcheal adolescents with AIS compared to controls. The concentrations of FSH, LH, oestradiol, and progesterone in postmenarcheal girls with scoliosis were lower, oestrone were slightly lower and oestriol did not differ compared with the control group. Significantly higher levels of RANKL, osteocalcin and AP were observed in postmenarcheal scoliotic adolescents compared with controls.

CONCLUSIONS

There is an interdependence between the concentration of oestradiol and development of scoliosis. Determination of estradiol may have diagnostic value in the screening of spinal pathologies associated with AIS.

Hyperandrogenism after menopause

Postmenopausal hyperandrogenism is a state of relative or absolute androgen excess originating from either the adrenals and/or the ovaries, clinically manifested as the appearance and/or increase in terminal hair growth or the development of symptoms/signs of virilization. In either settings, physicians need to evaluate such patients and exclude the presence of the relatively rare but potentially life-threatening underlying tumorous causes, particularly adrenal androgen-secreting tumors. It has been suggested that the rapidity of onset along with severity of symptom and the degree of androgen excess followed by relevant imaging studies may suffice to identify the source of excessive androgen secretion. However, up to date, there is no consensus regarding specific clinical and hormonal indices and/or imaging modalities required for diagnostic certainty. This is particularly relevant as the aging population is increasing and more cases of postmenopausal women with clinical/biochemical evidence of hyperandrogenism may become apparent. Furthermore, the long-term sequels of nontumorous hyperandrogenism in postmenopausal women in respect to cardiovascular morbidity and mortality still remain unsettled. This review delineates the etiology and pathophysiology of relative and absolute androgen excess in postmenopausal women. Also, it attempts to unravel distinctive clinical features along with specific hormonal cut-off levels and/or appropriate imaging modalities for the facilitation of the differential diagnosis and the identification of potential long-term sequels.

Testosterone dose dependently prevents bone and muscle loss in rodents after spinal cord injury

Androgen administration protects against musculoskeletal deficits in models of sex-steroid deficiency and injury/disuse. It remains unknown, however, whether testosterone prevents bone loss accompanying spinal cord injury (SCI), a condition that results in a near universal occurrence of osteoporosis. Our primary purpose was to determine whether testosterone-enanthate (TE) attenuates hindlimb bone loss in a rodent moderate/severe contusion SCI model. Forty (n=10/group), 14 week old male Sprague-Dawley rats were randomized to receive: (1) Sham surgery (T9 laminectomy), (2) moderate/severe (250 kdyne) SCI, (3) SCI+Low-dose TE (2.0 mg/week), or (4) SCI+High-dose TE (7.0 mg/week). Twenty-one days post-injury, SCI animals exhibited a 77-85% reduction in hindlimb cancellous bone volume at the distal femur (measured via μCT) and proximal tibia (measured via histomorphometry), characterized by a >70% reduction in trabecular number, 13-27% reduction in trabecular thickness, and increased trabecular separation. A 57% reduction in cancellous volumetric bone mineral density (vBMD) at the distal femur and a 20% reduction in vBMD at the femoral neck were also observed. TE dose dependently prevented hindlimb bone loss after SCI, with high-dose TE fully preserving cancellous bone structural characteristics and vBMD at all skeletal sites examined. Animals receiving SCI also exhibited a 35% reduction in hindlimb weight bearing (triceps surae) muscle mass and a 22% reduction in sublesional non-weight bearing (levator ani/bulbocavernosus [LABC]) muscle mass, and reduced prostate mass. Both TE doses fully preserved LABC mass, while only high-dose TE ameliorated hindlimb muscle losses. TE also dose dependently increased prostate mass. Our findings provide the first evidence indicating that high-dose TE fully prevents hindlimb cancellous bone loss and concomitantly ameliorates muscle loss after SCI, while low-dose TE produces much less profound musculoskeletal benefit. Testosterone-induced prostate enlargement, however, represents a potential barrier to the clinical implementation of high-dose TE as a means of preserving musculoskeletal tissue after SCI.

Current and future treatments of osteoporosis in men

One in three osteoporotic fractures occur in men and the consequences of a fracture in men tend to be more severe than in women. Still, only a small minority of men with high risk of fracture are detected and treated. Although there are gender differences in the pathophysiology of osteoporosis, such as in the pattern of bone loss, similarities predominate, which is also the case for clinical risk factors. It seems appropriate to consider treatment for men and women with a similar 10 year fracture risk. Drugs now approved for treatment of osteoporosis in men include the anti-resorptive bisphosphonates alendronate, residronate and zoledronic acid, the anti-resorptive drug denosumab, the bone-forming agent teriparatide, and (not in the US) strontium ranelate with mild opposite effects on resorption and formation. Although the evidence level for efficacy and safety of these drugs in men is still relatively limited, available data indicate that treatment effects in men are very similar to what has been observed in the treatment of postmenopausal osteoporosis. Denosumab is also approved for treatment in men receiving androgen deprivation therapy for non-metastatic prostate cancer; bisphosphonates and teriparatide are also available to clinicians for treatment of glucocorticoid-induced osteoporosis in men. Testosterone treatment may be indicated in men with documented symptomatic hypogonadism, but osteoporosis is neither a sufficient nor a specific indication for testosterone treatment. New compounds with well advanced clinical development include odanacatib, a selective inhibitor of the cysteine protease cathepsin-K, and romosozumab, a monoclonal antibody against sclerostin.

Bone mineral density in women with polycystic ovary syndrome

PURPOSE

PCOS is a complex disorder and various features of this disorder may have great importance for bone metabolism. The aim of the study was to determine the relationship between existing hormonal disorders, and bone mineral density (BMD) in young women with PCOS.

METHODS

69 reproductive-aged PCOS women and 30 age-matched healthy controls were enrolled to the study women. In each individual we assessed the body mass index (BMI). We evaluated the serum concentrations of: gonadotropins, prolactin (PRL), estradiol (E2), dehydroepiandrosterone sulfate (DHEAS), testosterone (T), thyroid stimulating hormone (TSH), free thyroxine (fT4). We used the Homeostatic Model Assessment-Insulin Resistance Index (HOMA-IR) to diagnose insulin resistance. Bone mineral density in the lumbar spine was measured by dual-energy X-ray absorptiometry (DXA).

RESULTS

The PCOS women had lower BMD values as compared to the controls (1.057 ± 0.1260 vs. 1.210 ± 0.1805 g/cm(2), p < 0.0002). In the analysis of PCOS patients according to BMI, only in the subgroup of the normal weight PCOS we find significantly lower BMD in comparison to controls (p = 0.0049). In patients with PCOS, BMD was positively correlated with insulin concentration and HOMA-IR. In the controls Z-score values were positively correlated with insulin concentration and HOMA-IR.

CONCLUSIONS

The deleterious effect of estrogen deficiency on bones in PCOS is not balanced by androgen overproduction. Women with PCOS had significantly lower BMD of the lumbar spine compared to controls. Insulin seems to be one of the most important positive bone growth stimulators.

Sex steroid actions in male bone

Sex steroids are chief regulators of gender differences in the skeleton, and male gender is one of the strongest protective factors against osteoporotic fractures. This advantage in bone strength relies mainly on greater cortical bone expansion during pubertal peak bone mass acquisition and superior skeletal maintenance during aging. During both these phases, estrogens acting via estrogen receptor-α in osteoblast lineage cells are crucial for male cortical and trabecular bone, as evident from conditional genetic mouse models, epidemiological studies, rare genetic conditions, genome-wide meta-analyses, and recent interventional trials. Genetic mouse models have also demonstrated a direct role for androgens independent of aromatization on trabecular bone via the androgen receptor in osteoblasts and osteocytes, although the target cell for their key effects on periosteal bone formation remains elusive. Low serum estradiol predicts incident fractures, but the highest risk occurs in men with additionally low T and high SHBG. Still, the possible clinical utility of serum sex steroids for fracture prediction is unknown. It is likely that sex steroid actions on male bone metabolism rely also on extraskeletal mechanisms and cross talk with other signaling pathways. We propose that estrogens influence fracture risk in aging men via direct effects on bone, whereas androgens exert an additional antifracture effect mainly via extraskeletal parameters such as muscle mass and propensity to fall. Given the demographic trends of increased longevity and consequent rise of osteoporosis, an increased understanding of how sex steroids influence male bone health remains a high research priority.

Androgens and estrogens in skeletal sexual dimorphism

Bone is an endocrine tissue expressing androgen and estrogen receptors as well as steroid metabolizing enzymes. The bioactivity of circulating sex steroids is modulated by sex hormone-binding globulin and local conversion in bone tissue, for example, from testosterone (T) to estradiol (E2) by aromatase, or to dihydrotestosterone by 5α-reductase enzymes. Our understanding of the structural basis for gender differences in bone strength has advanced considerably over recent years due to increasing use of (high resolution) peripheral computed tomography. These microarchitectural insights form the basis to understand sex steroid influences on male peak bone mass and turnover in cortical vs trabecular bone. Recent studies using Cre/LoxP technology have further refined our mechanistic insights from global knockout mice into the direct contributions of sex steroids and their respective nuclear receptors in osteoblasts, osteoclasts, osteocytes, and other cells to male osteoporosis. At the same time, these studies have reinforced the notion that androgen and estrogen deficiency have both direct and pleiotropic effects via interaction with, for example, insulin-like growth factor 1, inflammation, oxidative stress, central nervous system control of bone metabolism, adaptation to mechanical loading, etc., This review will summarize recent advances on these issues in the field of sex steroid actions in male bone homeostasis.

Human androgen deficiency: insights gained from androgen receptor knockout mouse models

The mechanism of androgen action is complex. Recently, significant advances have been made into our understanding of how androgens act via the androgen receptor (AR) through the use of genetically modified mouse models. A number of global and tissue-specific AR knockout (ARKO) models have been generated using the Cre-loxP system which allows tissue- and/or cell-specific deletion. These ARKO models have examined a number of sites of androgen action including the cardiovascular system, the immune and hemopoetic system, bone, muscle, adipose tissue, the prostate and the brain. This review focuses on the insights that have been gained into human androgen deficiency through the use of ARKO mouse models at each of these sites of action, and highlights the strengths and limitations of these Cre-loxP mouse models that should be considered to ensure accurate interpretation of the phenotype.