Androgens and bone

Considerations, possible contraindications, and potential mechanisms for deleterious effect in recreational and athletic use of selective androgen receptor modulators (SARMs) in lieu of anabolic androgenic steroids: A narrative review

Anabolic androgenic steroids (AAS) are testosterone and testosterone-derivative compounds sporadically employed by athletes and increasingly used recreationally to acquire a competitive edge or improve body composition. Nevertheless, users are subject to undesired side effects majorly associated with tissue-specific androgen receptor (AR) binding-mediated actions. More recently, selective AR modulators (SARMs) have gained popularity towards delivering androgen-associated anabolic actions with hopes of minimal androgenic effects. While several SARMs are in preclinical and clinical phases intended for demographics subject to hypogonadism, muscle wasting, and osteoporosis, several athletic organizations and drug testing affiliates have realized the increasingly widespread use of SARMs amongst competitors and have subsequently banned their use. Furthermore, recreational users are haphazardly acquiring these compounds from the internet and consuming doses several times greater than empirically reported. Unfortunately, online sources are rife with potential contamination, despite a prevailing public opinion suggesting SARMs are innocuous AAS alternatives. Considering each agent has a broad range of supporting evidence in both human and non-human models, it is important to comprehensively evaluate the current literature on commercially available SARMs to gain better understanding of their efficacy and if they can truly be considered a safer AAS alternative. Therefore, the purpose of this review is to discuss the current evidence regarding AAS and SARM mechanisms of action, demonstrate the efficacy of several prominent SARMs in a variety of scientific trials, and theorize on the wide-ranging contraindications and potential deleterious effects, as well as potential future directions regarding acute and chronic SARM use across a broad range of demographics.

Effects of androgen excess and glucocorticoid exposure on bone health in adult patients with 21-hydroxylase deficiency

CONTEXT

This study aimed to determine the role of modifiable predictors on bone health in congenital adrenal hyperplasia (CAH).

DESIGN

Cross-sectional, single center study, including 97 patients (N = 42 men) with classic CAH due to 21-hydroxylase deficiency (N = 65 salt wasting, N = 32 simple virilizing).

MAIN OUTCOME MEASURES

Treatment-related predictors of bone health.

RESULTS

Average T scores (-0.9 ± 1.4 vs. -0.4 ± 1.4; p = 0.036) as well as Z scores (-1.0 ± 1.3 vs. -0.1 ± 1.4; p = 0.012) at the spine in patients with CAH were significantly lower in men than women. While osteoporosis was rare in women, it was documented in 9.1% of men with CAH. There was a significant positive correlation of Z scores at the spine with advancing age in women with CAH (R² = 0.178; p = 0.003). In multivariate analysis, the intake of conventional hydrocortisone (HC) instead of synthetic glucocorticoids was independently associated with a higher bone mineral density (BMD) at the hip region in both sexes. In women, there was a positive association with vitamin D concentrations. Interestingly, higher sodium levels were associated with a lower BMD independent of renin levels and fludrocortisone dosage. Neither in men nor in women, markers of androgen control were predictive for BMD at any site. Markers of bone turnover indicated low bone turnover. No pathological fractures were documented.

CONCLUSIONS

Men with CAH are particularly prone to low bone density, while women seem to be relatively protected by androgen excess compared to the general female population. The use of HC instead of synthetic GCs for hormone replacement may translate into better bone health.

Vitamin D, Calcium, Parathyroid Hormone, and Sex Steroids in Bone Health and Effects of Aging

Bone health of the elderly is a major global health concern, since about 1 in 3 women and 1 in 5 men suffer from bone loss and fractures, often called osteoporosis, in old age. Bone health is a complex issue affected by multiple hormones and minerals. Among all the hormones involved in bone health, calcitriol (also vitamin D), parathyroid, and sex hormones (especially estrogen) have been discussed in this review paper. We have discussed the metabolism of these hormones and their effects on bone health. Vitamin D can be obtained from diet or formed from 7-dehydrocholesterol found under the skin in the presence of sunlight. The active form, calcitriol, causes dimerization of vitamin D receptor and acts on the bones, intestine, and kidney to regulate the level of calcium in blood. Similarly, parathyroid hormone is secreted when the serum level of calcium is low. It helps regulate the level of blood calcium through calcitriol. Sex hormones regulate bone modeling at an early age and remodeling later in life. Loss of ovarian function and a decrement in the level of production of estrogen are marked by bone loss in elderly women. In the elderly, various changes in the calcium and vitamin D metabolism, such as decrease in the production of vitamin D, decrease in dietary vitamin D, decreased renal production, increased production of excretory products, decrease in the level of VDR, and decreased calcium absorption by the intestines, can lead to bone loss. When the elderly are diagnosed with osteoporosis, medications that directly target bone such as bisphosphonates, RANK ligand inhibitors, estrogen and estrogen analogues, estrogen receptor modulators, and parathyroid hormone receptor agonists are used. Additionally, calcium and vitamin D supplements are prescribed.

Late-onset Hypogonadism: Bone health

BACKGROUND

Bone health is underdiagnosed and undermanaged in men. Bone loss occurs in men with hypogonadism and in aging men. Thus, patients with a diagnosis of late-onset hypogonadism (LOH) are at risk of osteoporosis and osteoporotic fractures.

OBJECTIVES

To provide an update on research data and clinical implications regarding bone health in men with LOH by reviewing literature articles on this issue.

MATERIALS AND METHODS

A thorough search of listed publications in PubMed on bone health in older men with hypogonadism was performed, and other articles derived from these publications were further identified.

RESULTS

Late-onset Hypogonadism may be associated with reduced bone mineral density (BMD). In a pathophysiological perspective, the detrimental effects of testosterone (T) deficiency on BMD are partly ascribed to relative estrogen deficiency and both serum T and serum estradiol (E2) need to be above 200 ng/dL and 20 pg/mL to prevent bone loss. The effects of exogenous T on BMD are controversial, but most of the studies confirm that testosterone replacement therapy (TRT) increases BMD and prevents further bone loss in men with hypogonadism. No data are available on TRT and the prevention of fractures.

DISCUSSION AND CONCLUSION

In men with documented LOH, a specific clinical workup should be addressed to the diagnosis of osteoporosis in order to program subsequent follow-up and consider specific bone active therapy. TRT should be started according to guidelines of male hypogonadism while keeping in mind that it may also have positive effects also on bone health in men with LOH.

Heme Oxygenase-1 Is a Pivotal Modulator of Bone Turnover and Remodeling: Molecular Implications for Prostate Cancer Bone Metastasis

Aims: Bone is the most frequent site of prostate cancer (PCa) metastasis. Tumor cells interact with the bone microenvironment interrupting tissue balance. Heme oxygenase-1 (HO-1; encoded by Hmox1) appears as a potential target in PCa maintaining the cellular homeostasis. Our hypothesis is that HO-1 is implicated in bone physiology and modulates the communication with PCa cells. Here we aimed at (i) assessing the physiological impact of Hmox1 gene knockout (KO) on bone metabolism in vivo and (ii) determining the alterations of the transcriptional landscape associated with tumorigenesis and bone remodeling in cells growing in coculture (PCa cells with primary mouse osteoblasts [PMOs] from BALB/c Hmox1+/+, Hmox1+/-, and Hmox1-/- mice). Results: Histomorphometric analysis of Hmox1-/- mice bones exhibited significantly decreased bone density with reduced remodeling parameters. A positive correlation between Hmox1 expression and Runx2, Col1a1, Csf1, and Opg genes was observed in PMOs. Flow cytometry studies revealed two populations of PMOs with different reactive oxygen species (ROS) levels. The high ROS population was increased in PMOs Hmox1+/- compared with Hmox1+/+, but was significantly reduced in PMOs Hmox1-/-, suggesting restrained ROS tolerance in KO cells. Gene expression was altered in PMOs upon coculture with PCa cells, showing a pro-osteoclastic profile. Moreover, HO-1 induction in PCa cells growing in coculture with PMOs resulted in a significant modulation of key bone markers such as PTHrP and OPG. Innovation and Conclusion: We here demonstrate the direct implications of HO-1 expression in bone remodeling and how it participates in the alterations in the communication between bone and prostate tumor cells.

Genetic Architecture Associated With Familial Short Stature

CONTEXT

Human height is an inheritable, polygenic trait under complex and multilocus genetic regulation. Familial short stature (FSS; also called genetic short stature) is the most common type of short stature and is insufficiently known.

OBJECTIVE

To investigate the FSS genetic profile and develop a polygenic risk predisposition score for FSS risk prediction.

DESIGN AND SETTING

The FSS participant group of Han Chinese ancestry was diagnosed by pediatric endocrinologists in Taiwan.

PATIENTS AND INTERVENTIONS

The genetic profiles of 1163 participants with FSS were identified by using a bootstrapping subsampling and genome-wide association studies (GWAS) method.

MAIN OUTCOME MEASURES

Genetic profile, polygenic risk predisposition score for risk prediction.

RESULTS

Ten novel genetic single nucleotide polymorphisms (SNPs) and 9 reported GWAS human height-related SNPs were identified for FSS risk. These 10 novel SNPs served as a polygenic risk predisposition score for FSS risk prediction (area under the curve: 0.940 in the testing group). This FSS polygenic risk predisposition score was also associated with the height reduction regression tendency in the general population.

CONCLUSION

A polygenic risk predisposition score composed of 10 genetic SNPs is useful for FSS risk prediction and the height reduction tendency. Thus, it might contribute to FSS risk in the Han Chinese population from Taiwan.

Ovariectomy Activates Chronic Low-Grade Inflammation Mediated by Memory T Cells, Which Promotes Osteoporosis in Mice

The loss of estrogen (E₂ ) initiates a rapid phase of bone loss leading to osteoporosis in one-half of postmenopausal women, but the mechanism is not fully understood. Here, we show for the first time how loss of E₂ activates low-grade inflammation to promote the acute phase of bone catabolic activity in ovariectomized (OVX) mice. E₂ regulates the abundance of dendritic cells (DCs) that express IL-7 and IL-15 by inducing the Fas ligand (FasL) and apoptosis of the DC. In the absence of E₂ , DCs become long-lived, leading to increased IL-7 and IL-15. We find that IL-7 and IL-15 together, but not alone, induced antigen-independent production of IL-17A and TNFα in a subset of memory T cells (T_MEM ). OVX of mice with T-cell-specific ablation of IL15RA showed no IL-17A and TNFα expression, and no increase in bone resorption or bone loss, confirming the role of IL-15 in activating the T_MEM and the need for inflammation. Our results provide a new mechanism by which E₂ regulates the immune system, and how menopause leads to osteoporosis. The low-grade inflammation is likely to cause or contribute to other comorbidities observed postmenopause. © 2020 American Society for Bone and Mineral Research.

The effects of estradiol are modulated in a tissue-specific manner in mice with inducible inactivation of ERα after sexual maturation

Mouse models with lifelong inactivation of estrogen receptor-α (ERα) show that ERα is the main mediator of estrogenic effects in bone, thymus, uterus, and fat. However, ERα inactivation early in life may cause developmental effects that confound the adult phenotypes. To address the specific role of adult ERα expression for estrogenic effects in bone and other nonskeletal tissues, we established a tamoxifen-inducible ERα-inactivated model by crossing CAGG-Cre-ER and ERα^flox/flox mice. Tamoxifen-induced ERα inactivation after sexual maturation substantially reduced ERα mRNA levels in cortical bone, trabecular bone, thymus, uterus, gonadal fat, and hypothalamus, in CAGG-Cre-ERα^flox/flox (inducible ERα^KO) compared with ERα^flox/flox (control) mice. 17β-estradiol (E2) treatment increased trabecular bone volume fraction (BV/TV), cortical bone area, and uterine weight, while it reduced thymus weight and fat mass in ovariectomized control mice. The estrogenic responses were substantially reduced in inducible ERα^KO mice compared with control mice on BV/TV (-67%), uterine weight (-94%), thymus weight (-70%), and gonadal fat mass (-94%). In contrast, the estrogenic response on cortical bone area was unaffected in inducible ERα^KO compared with control mice. In conclusion, using an inducible ERα^KO model, not confounded by lack of ERα during development, we demonstrate that ERα expression in sexually mature female mice is required for normal E2 responses in most, but not all, tissues. The finding that cortical, but not trabecular bone, responds normally to E2 treatment in inducible ERα^KO mice strengthens the idea of cortical and trabecular bone being regulated by estrogen via different mechanisms.

Autophagy: A Promising Target for Age-related Osteoporosis

Autophagy is a process the primary role of which is to clear up damaged cellular components such as long-lived proteins and organelles, thus participating in the conservation of different cells. Osteoporosis associated with aging is characterized by consistent changes in bone metabolism with suppression of bone formation as well as increased bone resorption. In advanced age, not only bone mass but also bone strength decrease in both sexes, resulting in an increased incidence of fractures. Clinical and animal experiments reveal that age-related bone loss is associated with many factors such as accumulation of autophagy, increased levels of reactive oxygen species, sex hormone deficiency, and high levels of endogenous glucocorticoids. Available basic and clinical studies indicate that age-associated factors can regulate autophagy. Those factors play important roles in bone remodeling and contribute to decreased bone mass and bone strength with aging. In this review, we summarize the mechanisms involved in bone metabolism related to aging and autophagy, supplying a theory for therapeutic targets to rescue bone mass and bone strength in older people.

Risk factors for heterotopic ossification in operatively treated proximal humeral fractures

AIMS

Heterotopic ossification (HO) is a potentially devastating complication of the surgical treatment of a proximal humeral fracture. The literature on the rate and risk factors for the development of HO under these circumstances is lacking. The aim of this study was to determine the incidence and risk factors for the development of HO in these patients.

METHODS

A retrospective analysis of 170 patients who underwent operative treatment for a proximal humeral fracture between 2005 and 2016, in a single institution, was undertaken. The mean follow-up was 18.2 months (1.5 to 140). The presence of HO was identified on follow-up radiographs.

RESULTS

The incidence of HO was 15% (n = 26). Our multivariate model revealed that male sex (odds ratio (OR) 3.57, 95% confidence interval (CI) 1.30 to 9.80 compared to female) and dislocation as the initial injury (OR 5.01, 95% CI 1.31 to 19.22) were significantly associated with the formation of HO (p < 0.05) while no significant associations were seen for the age of the patient, the characteristics of the injury, or the type of operative treatment.

CONCLUSION

This retrospective radiological study is the first to investigate the association between the method of surgical treatment for a proximal humeral fracture and the formation of HO postoperatively. We found that male sex and dislocation as the initial injury were risk factors for HO formation, whereas the method of surgical treatment, the age of the patient, and the pattern of the fracture were not predictive of HO formation. While additional studies are needed, these findings can help to identify those at an increased risk for HO formation under these circumstances. Cite this article: Bone Joint J 2020;102-B(4):539-544.

Differences in mineral composition and morphology between men and women in aortic valve calcification

Aortic valve calcification leads to the deposition of calcium phosphate minerals in the extracellular matrix of the aortic valve leaflets. The mineral deposits can severely narrow the opening of the aortic valve, leading to aortic stenosis. There are no therapies to halt or slow down disease progression and the mechanisms governing aortic valve calcification are still poorly understood. Recently, several studies have shown that for the same aortic stenosis severity, women present significantly lower calcification loads than men. The cause of this sex-related difference is unknown. To understand this difference, we analyzed mineral deposits from surgically excised calcified human aortic valves with different material characterization techniques. We find profound differences in mineral composition and morphology between sexes, which strongly suggest that minerals form slower in women than in men and follow a different mineralization pathway. This finding paves the way for new approaches specifically geared towards men or women in the diagnosis and treatment of aortic valve calcification. STATEMENT OF SIGNIFICANCE: Aortic valve calcification is a health disorder with increasing prevalence and high morbidity and mortality. Currently there is no approved effective treatment; the only available therapeutic option is invasive valve replacement, to which not all patients are suited. The main reason for such lack of treatment options is our lack of understanding of the calcification mechanism. In this study, we show profound differences in mineral composition and morphology between sexes, suggesting that aortic valve calcification follows different mineralization pathways in men and women. These findings pave the way for new approaches specifically geared towards men or women in the diagnosis and treatment of aortic valve calcification.

Revisiting the Population Genetics of Human Height

CONTEXT

Recent advances in genetics and genomics present unique opportunities for enhancing knowledge of human physiology and disease susceptibility. An outstanding example of these new insights may be seen in the study of human height, of which it has been estimated that approximately 80% is genetically determined. Over the past decade, large-scale population analyses have led to the identification of novel variation in genes and loci individually associated with changes in adult height of as much as 2 cm.

OBJECTIVE

To assess these same variants in the genomes of 213 158 individuals compiled by the Genome Aggregation Database (GnomAD) consortium, representing different population groups from around the world.

RESULTS

The majority of these height-changing alleles are substantially less prevalent in GnomAD than found previously in other cohorts, with 4 of 5 amino acid substitution variants with the largest impact on adult height being more frequent in the European population than in other groups.

CONCLUSIONS

A larger-scale analysis of individuals from diverse backgrounds will be necessary to ensure a full and accurate understanding of the genetic underpinnings of human height throughout the world, and additional studies will be needed to discern the biochemical and molecular mechanisms governing the physiological processes that explain how these variant proteins might selectively impact the biology of the growth plate. Broader understanding of the genetics of height also should set the stage for more comprehensive investigation into the causes of prevalent polygenic human diseases.

Aortic Valve Stenosis: From Basic Mechanisms to Novel Therapeutic Targets

Aortic valve stenosis is the most prevalent heart valve disease worldwide. Although interventional treatment options have rapidly improved in recent years, symptomatic aortic valve stenosis is still associated with high morbidity and mortality. Calcific aortic valve stenosis is characterized by a progressive fibro-calcific remodeling and thickening of the aortic valve cusps, which subsequently leads to valve obstruction. The underlying pathophysiology is complex and involves endothelial dysfunction, immune cell infiltration, myofibroblastic and osteoblastic differentiation, and, subsequently, calcification. To date, no pharmacotherapy has been established to prevent aortic valve calcification. However, novel promising therapeutic targets have been recently identified. This review summarizes the current knowledge of pathomechanisms involved in aortic valve calcification and points out novel treatment strategies.

Exploratory Evidence of Sex-Dimorphic Associations of the Ulna-to-Fibula Ratio, a Potential Marker of Pubertal Sex Steroid Exposure, with the Implicit Need for Power

Objectives

We propose a novel marker of pubertal organizing hormone effects on the brain, long bone length, and assess its relationships to implicit motives, especially the implicit need for power (nPower).

Methods

In a partly exploratory approach, we tested 126 participants (after exclusions; 53 men, 73 women), in a cross-sectional design using the Picture-Story Exercise (nPower, activity inhibition), standard anthropometric measurements (BMI, height), and calipers to assess bone length of the ulna and fibula.

Results

Results indicated that a sex-dimorphic (d = 0.55) Ulna-to-Fibula Ratio (UFR), which is independent of body height, best captures the variance in our data. While we did not find bivariate relationships between long bone length and nPower, a sex-dimorphic interaction of nPower and activity inhibition on UFR-asymmetry (UFRr-l; right versus left UFR) emerged. High UFRr-l scores were related to the inhibited power motive (high nPower, high activity inhibition) in men, while for women the pattern was (non-significantly) reversed. In addition, UFR was predicted by a sex-dimorphic effect of nPower, with low UFR scores being associated with a higher nPower in men and a tendency for high UFR scores being related to lower nPower in women.

Conclusions

We discuss our results regarding UFR’s potential as a sex-dimorphic marker of the organizing effects of pubertal steroid hormones on the motivational brain beyond hand and face parameters routinely used in current research. Finally, we examine how our findings fit recent results obtained for the relationship between 2D:4D digit ratio or facial width-to-height ratio and nPower.

Hypogonadism, Type-2 Diabetes Mellitus, and Bone Health: A Narrative Review

One of the complications from chronic hyperglycemia and insulin resistance due to type 2 diabetes mellitus (T2DM) on the hypothalamic-pituitary-gonadal axis in men is the high prevalence of hypogonadotropic hypogonadism (HH). Both T2DM and hypogonadism are associated with impaired bone health and increased fracture risk but whether the combination results in even worse bone disease than either one alone is not well-studied. It is possible that having both conditions predisposes men to an even greater risk for fracture than either one alone. Given the common occurrence of HH or hypogonadism in general in T2DM, a significant number of men could be at risk. To date, there is very little information on the bone health men with both hypogonadism and T2DM. Insulin resistance, which is the primary defect in T2DM, is associated with low testosterone (T) levels in men and may play a role in the bidirectional relationship between these two conditions, which together may portend a worse outcome for bone. The present manuscript aims to review the available evidences on the effect of the combination of hypogonadism and T2DM on bone health and metabolic profile, highlights the possible metabolic role of the skeleton, and examines the pathways involved in the interplay between bone, insulin resistance, and gonadal steroids.

Hormesis in Health and Chronic Diseases

'What doesn't kill you makes you stronger'. Hormesis, the paradoxical beneficial effects of low-dose stressors, can be better defined as the biphasic dose-effect or time-effect relationship for any substance. Here we review hormesis-like phenomena in the context of chronic diseases for many substances, including lifestyle factors and endocrine factors. Intermittent or pulsatile exposure can generate opposite effects compared with continuous exposure. An initial exposure can elicit an adaptive stress response with long-lasting protection against subsequent exposures. Early-life stress can increase resilience in later life and lack of stress can lead to vulnerability. Many stressors are naturally occurring and are required for healthy growth or homeostasis, which exemplifies how 'illness is the doorway to health'.

Androgens and Androgen Receptor Actions on Bone Health and Disease: From Androgen Deficiency to Androgen Therapy

Androgens are not only essential for bone development but for the maintenance of bone mass. Therefore, conditions with androgen deficiency, such as male hypogonadism, androgen-insensitive syndromes, and prostate cancer with androgen deprivation therapy are strongly associated with bone loss and increased fracture risk. Here we summarize the skeletal effects of androgens—androgen receptors (AR) actions based on in vitro and in vivo studies from animals and humans, and discuss bone loss due to androgens/AR deficiency to clarify the molecular basis for the anabolic action of androgens and AR in bone homeostasis and unravel the functions of androgen/AR signaling in healthy and disease states. Moreover, we provide evidence for the skeletal benefits of androgen therapy and elucidate why androgens are more beneficial than male sexual hormones, highlighting their therapeutic potential as osteoanabolic steroids in improving bone fracture repair. Finally, the application of selective androgen receptor modulators may provide new approaches for the treatment of osteoporosis and fractures as well as building stronger bones in diseases dependent on androgens/AR status.

TMPRSS2-ERG fusions confer efficacy of enzalutamide in an in vivo bone tumor growth model

BACKGROUND

Castrate Resistant Prostate Cancer (CRPC) is an advanced disease resistant to systemic traditional medical or surgical castration, and resistance is primarily attributed to reactivation of AR through multiple mechanisms. TMPRSS2-ERG fusions have been shown to regulate AR signaling, interfere with pro-differentiation functions, and mediate oncogenic signaling. We have recently shown that ERG regulates intra-tumoral androgen synthesis and thereby facilitates AR function in prostate cancer cells. We hypothesize that enzalutamide treatment will be more effective in cells/tumors with TMPRSS2-ERG translocations because these tumors have increased AR signaling.

METHODS

ERG knockdown was performed with VCaP cells using lentiviral infections to generate VCaP ERGshRNA cells and control VCaP scr cells with scrambled shRNA. Cell-growth analysis was performed to determine the effect of enzalutamide. Reverse transcription, quantitative real-time PCR (RT-qPCR) was used to determine the expression of AR responsive genes. Luciferase tagged VCaP scr and shRNA infected cells were used in an intra-tibial animal model for bone tumor growth analysis and enzalutamide treatment used to inhibit AR signaling in bone tumors. Western blotting analyzed VCaP bone tumor samples for ERG, AR, AKR1C3 and HSD3B1 and HSD3B2 expression.

RESULTS

Enzalutamide inhibited the growth of VCaP scr cells more effectively than shERG cells. Analysis of AR responsive genes shows that Enzalutamide treatment at 5 micromolar concentration inhibited by 85-90% in VCaP Scr cells whereas these genes were inhibited to a lesser extent in VCaP shERG cells. Enzalutamide treatment resulted in severe growth inhibition in VCaP scr shRNA cells compared to VCaP shERG cells. In bone tumor growth experiment, VCaP ERG shRNA cells grew at slower than VCaP scr shRNA cells. Androgen biosynthetic enzyme expression is lower VCaP shERG bone tumors compared to VCaP scr shRNA bone tumors and enzalutamide inhibited the enzyme expression in both types of tumors.

CONCLUSIONS

These data suggest that ERG transcription factor regulates androgen biosynthetic enzyme expression that enzalutamide treatment is more effective against VCaP bone tumors with an intact ERG expression, and that knocking down ERG in VCaP cells leads to a lesser response to enzalutamide therapy. Thus, ERG expression status in tumors could help stratify patients for enzalutamide therapy.

Design, Synthesis, and Biological Characterization of Orally Active 17β-Hydroxysteroid Dehydrogenase Type 2 Inhibitors Targeting the Prevention of Osteoporosis

Osteoporosis is predominantly treated with drugs that inhibit further bone resorption due to estrogen deficiency. Yet, osteoporosis drugs that not only inhibit bone resorption but also stimulate bone formation, such as potentially inhibitors of 17β-hydroxysteroid dehydrogenase type 2 (17β-HSD2), may be more efficacious in the treatment of osteoporosis. Blockade of 17β-HSD2 is thought to increase intracellular estradiol and testosterone in bone, thereby inhibiting bone resorption by osteoclasts and stimulating bone formation by osteoblasts, respectively. We here describe the design, synthesis, and biological characterization of a novel bicyclic-substituted hydroxyphenylmethanone 17β-HSD2 inhibitor (compound 24). Compound 24 is a nanomolar potent inhibitor of human 17β-HSD2 (IC₅₀ of 6.1 nM) and rodent 17β-HSD2 with low in vitro cellular toxicity, devoid of detectable estrogen receptor α affinity, displays high aqueous solubility and in vitro metabolic stability, and has an excellent oral pharmacokinetic profile for testing in a rat osteoporosis model. Administration of 24 in a rat osteoporosis model demonstrates its bone-sparing efficacy.

Morphometric signals of population decline in diademed sifakas occupying degraded rainforest habitat in Madagascar

Anthropogenic habitat change can have varied impacts on primates, including both negative and positive outcomes. Even when behavioural shifts are seen, they may reflect decreased health, or simply behavioural flexibility; understanding this distinction is important for conservation efforts. This study examines habitat-related variation in adult and immature morphometrics among diademed sifakas (Propithecus diadema). We collected morphometric data from sifakas at Tsinjoarivo, Madagascar (19 years, 188 captures, 113 individuals). Captures spanned 12 groups, five within continuous forest ("CONT"), and seven in degraded fragments ("FRAG") where sifakas have lower nutritional intakes. Few consistent differences were found between CONT and FRAG groups. However, using home range quality as a covariate rather than a CONT/FRAG dichotomy revealed a threshold: the two FRAG groups in the lowest-quality habitat showed low adult mass and condition (wasting), and low immature mass and length (stunting). Though less-disturbed fragments apparently provide viable habitat, we suggest the sifakas in the most challenging habitats cannot evolve fast enough to keep up with such rapid habitat change. We suggest other long-lived organisms will show similar morphometric "warning signs" (wasting in adults, stunting in immatures); selected morphometric variables can thus be useful at gauging vulnerability of populations in the face of anthropogenic change.

Gender-Affirming Hormone Therapy for Transgender Men

There are an estimated 1.4 million transgender adults in the United States, and lack of providers knowledgeable in transgender care is a barrier to health care. Obstetricians and Gynecologists can help increase access in part by becoming competent in gender-affirming hormone therapy. For transgender men, testosterone protocols can be extrapolated from those used for hypogonadal cisgender men. Unfortunately, there are not any high-quality, long-term prospective studies on the effectiveness and safety of different testosterone regimens specifically in transgender men, but the available data suggest that gender-affirming testosterone therapy is safe and effective with proper screening and monitoring.

Impact of estrogens in males and androgens in females

Androgens and estrogens are known to be critical regulators of mammalian physiology and development. While these two classes of steroids share similar structures (in general, estrogens are derived from androgens via the enzyme aromatase), they subserve markedly different functions via their specific receptors. In the past, estrogens such as estradiol were thought to be most important in the regulation of female biology, while androgens such as testosterone and dihydrotestosterone were believed to primarily modulate development and physiology in males. However, the emergence of patients with deficiencies in androgen or estrogen hormone synthesis or actions, as well as the development of animal models that specifically target androgen- or estrogen-mediated signaling pathways, have revealed that estrogens and androgens regulate critical biological and pathological processes in both males and females. In fact, the concept of "male" and "female" hormones is an oversimplification of a complex developmental and biological network of steroid actions that directly impacts many organs. In this Review, we will discuss important roles of estrogens in males and androgens in females.

Canadian newcomer children's bone health and vitamin D status

Adequate calcium intake and supply of vitamin D during childhood play important roles in ensuring adequate bone mass gain to achieve optimal peak bone mass. The Healthy Immigrant Children study employed a mixed-method cross-sectional study design to characterize the health and nutritional status of 300 immigrant and refugee children aged 3-13 years who had been in Canada for less than 5 years. This paper presents bone mineral content and vitamin D status data along with qualitative data that deepen the understanding of newcomer bone health status. A significantly higher percentage of refugee children (72.3%) had insufficient (<50 nmol/L) or deficient (<30 nmol/L) serum vitamin D compared with immigrants (53.2%). Vitamin D deficiency was most common among ethnic minority girls. Newcomer children with higher intakes of vitamin D, younger newcomer children, and those from western Europe or the United States had higher serum vitamin D levels. Immigrants had significantly higher mean total body bone mineral content compared with refugees. Total body fat, serum vitamin D, calcium intake, height, height by calcium intake, total body fat by calcium intake, and total body fat by height predicted total body bone mineral content levels. Vitamin D deficiency among newcomer children may be related to lack of knowledge regarding children's vitamin D requirements in the Canadian environment, dietary habits established in country of origin, low income that limits healthy dietary choices, and lifestyle habits that limit exposure to sunlight. Results suggest a need to screen newcomer children and pregnant women for vitamin D deficiency and support early intervention.

Different Clinical Presentations and Management in Complete Androgen Insensitivity Syndrome (CAIS)

Complete androgen insensitivity syndrome (CAIS) is an X-linked recessive genetic disorder resulting from maternally inherited or de novo mutations involving the androgen receptor gene, situated in the Xq11-q12 region. The diagnosis is based on the presence of female external genitalia in a 46, XY human individual, with normally developed but undescended testes and complete unresponsiveness of target tissues to androgens. Subsequently, pelvic ultrasound or magnetic resonance imaging (MRI) could be helpful in confirming the absence of Mullerian structures, revealing the presence of a blind-ending vagina and identifying testes. CAIS management still represents a unique challenge throughout childhood and adolescence, particularly regarding timing of gonadectomy, type of hormonal therapy, and psychological concerns. Indeed this condition is associated with an increased risk of testicular germ cell tumour (TGCT), although TGCT results less frequently than in other disorders of sex development (DSD). Furthermore, the majority of detected tumoral lesions are non-invasive and with a low probability of progression into aggressive forms. Therefore, histological, epidemiological, and prognostic features of testicular cancer in CAIS allow postponing of the gonadectomy until after pubertal age in order to guarantee the initial spontaneous pubertal development and avoid the necessity of hormonal replacement therapy (HRT) induction. However, HRT is necessary after gonadectomy in order to prevent symptoms of hypoestrogenism and to maintain secondary sexual features. This article presents differential clinical presentations and management in patients with CAIS to emphasize the continued importance of standardizing the clinical and surgical approach to this disorder.

Clinical Management of Congenital Hypogonadotropic Hypogonadism

The initiation and maintenance of reproductive capacity in humans is dependent on pulsatile secretion of the hypothalamic hormone GnRH. Congenital hypogonadotropic hypogonadism (CHH) is a rare disorder that results from the failure of the normal episodic GnRH secretion, leading to delayed puberty and infertility. CHH can be associated with an absent sense of smell, also termed Kallmann syndrome, or with other anomalies. CHH is characterized by rich genetic heterogeneity, with mutations in >30 genes identified to date acting either alone or in combination. CHH can be challenging to diagnose, particularly in early adolescence where the clinical picture mirrors that of constitutional delay of growth and puberty. Timely diagnosis and treatment will induce puberty, leading to improved sexual, bone, metabolic, and psychological health. In most cases, patients require lifelong treatment, yet a notable portion of male patients (∼10% to 20%) exhibit a spontaneous recovery of their reproductive function. Finally, fertility can be induced with pulsatile GnRH treatment or gonadotropin regimens in most patients. In summary, this review is a comprehensive synthesis of the current literature available regarding the diagnosis, patient management, and genetic foundations of CHH relative to normal reproductive development.

Targeted Endocrine Therapy: Design, Synthesis, and Proof-of-Principle of 17β-Hydroxysteroid Dehydrogenase Type 2 Inhibitors in Bone Fracture Healing

Current therapies of steroid hormone-dependent diseases predominantly alter steroid hormone concentrations (or their actions) in plasma, in target and nontarget tissues alike, rather than in target organs only. Targeted therapy through the inhibition of steroidogenic enzymes may pose an attractive alternative with much less side effects. Here, we describe the design of a nanomolar potent 17β-hydroxysteroid dehydrogenase type 2 (17β-HSD2) inhibitor (compound 15) and successful targeted intracrine therapy in a mouse bone fracture model. Blockade of 17β-HSD2 in bone is thought to increase intracellular estradiol (E2) and testosterone (T), which thereby inhibits bone resorption by osteoclasts and stimulates bone formation by osteoblasts, respectively. Administration of compound 15 in the mouse fracture model strongly increases the mechanical stability of the healing fractured bone because of a larger periosteal callus with newly formed bone without changing the plasma E2 and T concentrations. Steroidogenic 17β-HSD2 inhibition thus enables targeted intracrine therapy.

Gonadal Hormones and Bone

In both sexes, estrogen is one of the most essential hormones for maintaining bone integrity. Also, especially in men, androgen has beneficial effects on bone independent of estrogen. However, estrogen replacement therapy for postmenopausal women increases the risk of developing breast cancer and endometrial cancer, and androgen replacement therapy for partial androgen deficiency of the aging male increases the risk of developing prostate cancer. Various mechanisms have been proposed on the effects of gonadal hormones on bone, such as effects through cytokines including IL-6 and effects on the OPG/RANKL ratio. In addition, large amounts of new information deriving from high-throughput gene expression analysis raise the possibility of multiple other effects on bone cells. Both estrogen and androgen exert their effects via the estrogen receptor (ER) or the androgen receptor (AR), which belongs to the nuclear receptor superfamily. Compounds such as selective estrogen receptor modulators (SERMs) and selective androgen receptor modulators (SARMs) also bind ER and AR, respectively. However, SERMs and SARMs alter the ER or AR structure differently from estrogen or androgen, resulting in other downstream gene responses. As a result they can exert favorable effects on bone while suppressing the undesirable actions of estrogen and androgen. Elucidation of ER and AR ligand-specific and tissue-specific gene regulation mechanisms will also provide information on the signal transduction mechanisms of other nuclear receptors and will be valuable for the development of new therapeutic agents.

Effects of Osteocalcin on Synthesis of Testosterone and INSL3 during Adult Leydig Cell Differentiation

Proliferation and differentiation of adult Leydig cells are mainly completed in puberty. In many studies, apart from normal postnatal development process, it is widely indicated that, through administrating EDS, Leydig cell population is eliminated and regenerated. It is believed that osteocalcin released from osteoblasts, which is responsible for modulating bone metabolism, induces testosterone production in Leydig cells, independent of the HPG axis. In addition, INSL3 produced by Leydig cells, such as testosterone, plays a critical role in bone metabolism and is known to reflect the development process and functional capacities of Leydig cells. This study is aimed at investigating OC-mediated testosterone regulation and INSL3 synthesis during differentiation of adult Leydig cells that are independent of LH. For this purpose, male rats were divided into 2 groups: prepubertal normal rats and adult EDS-injected rats. Each group was divided into 4 subgroups in which GnRH antagonist or OC was applied. After adult Leydig cells completed their development, testicular tissue samples obtained from the sacrificed rats were examined by light-electron microscopic, immunohistochemical, and biochemical methods. Slight upregulation in 3βHSD, INSL3, and GPRC6A expressions along with the increase in serum testosterone levels was observed in groups treated with osteocalcin against GnRH antagonist. In addition, biochemical and microscopic findings in osteocalcin treated groups were similar to those in control groups. While there was no significant difference in the number of Leydig cells reported, the presence of a significant upregulation in INSL3 and GPRC6A expressions and the increase in serum testosterone and ucOC levels were observed. After evaluation of findings altogether, it is put forward that, for the first time in this study, although osteocalcin treatment made no significant difference in the number of Leydig cells, it increased the level of testosterone through improving the function of existing adult Leydig cells during normal postnatal development process and post-EDS regeneration. This positive correlation between osteocalcin-testosterone and osteocalcin-INSL3 is concluded to be independent of LH at in vivo conditions.

Stanozolol promotes osteogenic gene expression and apposition of bone mineral in vitro

Stanozolol (ST) is a synthetic androgen with high anabolic potential. Although it is known that androgens play a positive role in bone metabolism, ST action on bone cells has not been sufficiently tested to support its clinical use for bone augmentation procedures. Objective: This study aimed to assess the effects of ST on osteogenic activity and gene expression in SaOS-2 cells. Material and Methods: SaOS-2 deposition of mineralizing matrix in response to increasing doses of ST (0-1000 nM) was evaluated through Alizarin Red S and Calcein Green staining techniques at 6, 12 and 24 days. Gene expression of runt-related transcription factor 2 (RUNX2), vitamin D receptor (VDR), osteopontin (SPP1) and osteonectin (ON) was analyzed by RT-PCR. Results: ST significantly influenced SaOS-2 osteogenic activity: stainings showed the presence of rounded calcified nodules, which increased both in number and in size over time and depending on ST dose. RT-PCR highlighted ST modulation of genes related to osteogenic differentiation. Conclusions: This study provided encouraging results, showing ST promoted the osteogenic commitment of SaOS-2 cells. Further studies are required to validate these data in primary osteoblasts and to investigate ST molecular pathway of action.

Resistance Training Is Associated With Higher Bone Mineral Density Among Young Adult Male Distance Runners Independent of Physiological Factors

Duplanty, AA, Levitt, DE, Hill, DW, McFarlin, BK, DiMarco, NM, and Vingren, JL. Resistance training is associated with higher bone mineral density among young adult male distance runners independent of physiological factors. J Strength Cond Res 32(6): 1594-1600, 2018-Low bone mineral density (BMD) in male distance runners is common and could be modulated by a host of biomarkers involved in the dynamic balance of bone tissue. In contrast, resistance training can increase BMD; however, the efficacy of resistance training in protecting BMD in distance runners has not been elucidated. The aim of this study was to investigate the relationship between resistance training, testosterone and bone metabolism biomarker concentrations, and BMD in young adult male distance runners. Twenty-five apparently healthy men (23-32 years; mean ± SD: 25.9 ± 2.9 years; 1.77 ± 0.04 m; 75.4 ± 8.5 kg) were categorized into 1 of 3 groups: untrained control participants (CON; n = 8); nonresistance-trained runners (NRT; n = 8); or resistance-trained runners (RT; n = 9). Blood was collected and analyzed for concentrations of free and total testosterone and 14 bone metabolism biomarkers. Bone mineral density was assessed using dual-energy X-ray absorptiometry. At all measured sites, BMD was greater (p ≤ 0.05) for RT compared with NRT and CON. Vitamin D concentration was greater (p ≤ 0.05) in RT and NRT compared with CON. Concentrations of testosterone and remaining bone biomarkers did not differ between groups (p > 0.05). Resistance-trained runners had greater BMD than nonresistance-trained runners and untrained peers. This difference did not seem to be modulated by biomarkers that contribute to bone formation or resorption, indicating that differences in BMD are associated with habitual load-bearing exercise using external resistance. Runners should perform resistance exercise at least once per week because this is associated with greater BMD.

Pituitary Diseases and Bone

Neuroendocrinology of bone is a new area of research based on the evidence that pituitary hormones may directly modulate bone remodeling and metabolism. Skeletal fragility associated with high risk of fractures is a common complication of several pituitary diseases such as hypopituitarism, Cushing disease, acromegaly, and hyperprolactinemia. As in other forms of secondary osteoporosis, pituitary diseases generally affect bone quality more than bone quantity, and fractures may occur even in the presence of normal or low-normal bone mineral density as measured by dual-energy X-ray absorptiometry, making difficult the prediction of fractures in these clinical settings. Treatment of pituitary hormone excess and deficiency generally improves skeletal health, although some patients remain at high risk of fractures, and treatment with bone-active drugs may become mandatory. The aim of this review is to discuss the physiological, pathophysiological, and clinical insights of bone involvement in pituitary diseases.

Phenotypic plasticity in genitalia: baculum shape responds to sperm competition risk in house mice

Males are known to adjust their expenditure on testes growth and sperm production in response to sperm competition risk. Genital morphology can also contribute to competitive fertilization success but whether male genital morphology can respond plastically to the sperm competition environment has received little attention. Here, we exposed male house mice to two different sperm competition environments during their sexual development and quantified phenotypic plasticity in baculum morphology. The sperm competition environment generated plasticity in body growth. Males maturing under sperm competition risk were larger and heavier than males maturing under no sperm competition risk. We used a landmark-based geometric morphometric approach to measure baculum size and shape. Independent of variation in body size, males maintained under risk of sperm competition had a relatively thicker and more distally extended baculum bulb compared with males maintained under no sperm competition risk. Plasticity in baculum shape paralleled evolutionary responses to selection from sperm competition reported in previous studies of house mice. Our findings provide experimental evidence of socially mediated phenotypic plasticity in male genitalia.

The Effects of Chemical Castration with Degarelix on Bone Turnover: Densitometric and Biomechanics Bone Properties of Male Rats

BACKGROUND

Gonadotropin releasing hormone (GnRH) antagonists may cause chemical castration in males by suppressing the pituitary-gonadal axis, hence reducing testosterone level. There are limited data on the effects of degarelix, a newer series of potent and long acting GnRH antagonist on bone.

OBJECTIVES

The current study aimed at determining the effects of degarelix on bone turnover, bone densitometry, and bone mechanical strength in male rats.

METHODS

Eighteen male Sprague-Dawley rats were randomly divided into sham (SHAM), orchidectomized (ORX), and degarelix-induced (DGX) groups. Chemical castration was performed by subcutaneous degarelix injection (2 mg/kg) at the scapular region. The rats were scanned for baseline bone mineral area (BMA), bone mineral content (BMC), and bone mineral density (BMD) using dual-energy x-ray absorptiometry (DXA). Following six weeks of experimental period, BMA, BMC, and BMD were measured again with DXA and blood was collected for testosterone and bone biomarkers (osteocalcin and C-terminal of type I collagen crosslink (CTX-1)) measurements. The rats were euthanized and femora were dissected for bone biomechanical strength analysis.

RESULTS

Bilateral orchidectomy and degarelix administration significantly lowered serum testosterone level, decreased whole body BMC, femoral BMA, femoral BMC, and femoral BMD (P < 0.05) compared with the SHAM group. However, no significant changes were observed in bone biochemical markers and bone mechanical strength in all experimental groups.

CONCLUSIONS

In conclusion, degarelix administration had comparable effects on bone as bilateral orchidectomy. Administration of degarelix provides an alternative method of inducing testosterone deficient-osteopenia in male rats without need for removing the testes.

Proandrogenic and Antiandrogenic Progestins in Transgender Youth: Differential Effects on Body Composition and Bone Metabolism

CONTEXT

Progestins can be used to attenuate endogenous hormonal effects in late-pubertal transgender (trans) adolescents (Tanner stage B4/5 and G4/5). Currently, no data are available on the effects of progestins on the development of bone mass or body composition in trans youth.

OBJECTIVE

To study prospectively the evolution of body composition and bone mass in late-pubertal trans adolescents using the proandrogenic or antiandrogenic progestins lynestrenol (L) and cyproterone acetate (CA), respectively.

DESIGN AND OUTCOME MEASUREMENTS

Forty-four trans boys (Tanner B4/5) and 21 trans girls (Tanner G4/5) were treated with L or CA for 11.6 (4 to 40) and 10.6 (5 to 31) months, respectively. Anthropometry, grip strength, body composition, and bone mass, size, and density were determined by dual-energy X-ray absorptiometry and peripheral quantitative computed tomography before the start of progestin and before addition of cross-sex hormones.

RESULTS

Using L, lean mass [+3.2 kg (8.6%)] and grip strength [+3 kg (10.6%)] significantly increased, which coincided with a more masculine body shape in trans boys. Trans girls showed loss of lean mass [-2.2 kg (4.7%)], gain of fat mass [+1.5 kg (9.4%)], and decreased grip strength Z scores. CA limited normal bone expansion and impeded pubertal bone mass accrual, mostly at the lumbar spine [Z score: -0.765 to -1.145 (P = 0.002)]. L did not affect physiological bone development.

CONCLUSION

Proandrogenic and antiandrogenic progestins induce body composition changes in line with the desired appearance within 1 year of treatment. Bone health, especially at the lumbar spine, is of concern in trans girls, as bone mass accrual is severely affected by androgen suppressive therapy.

Sex-Related Differences in the Developmental Morphology of the Atlas: A Computed Tomography Study

STUDY DESIGN

A retrospective study.

OBJECTIVE

To elucidate sex-related differences in the age at synchondroses closure, the normative size of the atlas, and the ossification patterns of the atlas in Japanese children.

SUMMARY OF BACKGROUND DATA

The atlas develops from three ossification centers during childhood. The anterior and posterior synchondroses, which are separate ossification centers, mimic fracture lines on computed tomography (CT). Sex-related differences of age dependent morphological changes of the atlas in a large sample size have not been reported.

METHODS

This study analyzed data of 688 subjects (449 boys) between 0 and 18 years old who underwent CT examination of the head and/or neck between January 2010 and July 2016. The age at synchondroses closure, anteroposterior outer, inner, and spinal canal widths of the atlas, and variations of the ossification centers were examined.

RESULTS

Anterior synchondroses closed by 10 years in boys and by 7 years in girls. Significant earlier closure of anterior synchondroses was observed in girls than in boys (P < 0.05 at 4 and 5 years old). Posterior synchondrosis closed by 6 years in boys and by 5 years in girls. The outer, inner, and spinal canal widths increased up to 10 to 15 years in both sexes, although all three parameters in girls peaked 3 years earlier than those in boys. All parameters in boys were significantly larger than those in girls, except in the 10- to 12-year-old age category. Two or more ossification centers in the anterior arch were observed in 18.3% subjects, and 6% had midline ossification centers in the posterior arch of the atlas.

CONCLUSION

Distinct sex-related differences in the age at anterior synchondroses closure and the size of the atlas were observed in Japanese children. Knowledge of morphological features of the atlas could help distinguish fractures from synchondroses.

LEVEL OF EVIDENCE

3.

Birth size, body composition, and adrenal androgens as determinants of bone mineral density in mid-childhood

BackgroundBirth weight has an impact on adult bone mass. Higher birth weight is associated with greater bone mineral content (BMC) and children born small for gestational age (SGA) are at an increased risk for impaired accrual of bone mass. Our aim was to study whether the impact of birth size or early childhood growth on bone mass is visible already in mid-childhood.MethodsWe studied 49 children born large for gestational age (LGA), 56 children born appropriate for gestational age (AGA), and 23 children born SGA at 5.0-8.7 years of age. Body composition was assessed by whole-body dual-energy X-ray absorptiometry. Fasting blood samples and anthropometric data were collected.ResultsThe children born SGA had lower bone mineral density (BMD) Z-score (P<0.001) and age- and sex-adjusted BMD (P<0.005) than the LGA and AGA children. Adjusted BMC, muscle mass, and body fat percentage (%BF) did not differ between the study groups. Muscle mass, BMI SD score (SDS), %BF, and serum dehydroepiandrosterone sulfate (DHEAS) concentration were the strongest predictors of high BMD in mid-childhood.ConclusionSGA-born children had lower BMD in mid-childhood compared with AGA- and LGA-born ones. Muscle mass or BMI SDS, %BF, and DHEAS were significant predictors of childhood BMD.

Tissue control of androgen action: The ups and downs of androgen receptor expression

The hormone testosterone plays crucial roles during male development and puberty and throughout life, as an anabolic regulator of muscle and bone structure and function. The actions of testosterone are mediated, primarily, through the androgen receptor, a member of the nuclear receptor superfamily. The androgen receptor gene is located on the X-chromosome and receptor levels are tightly controlled both at the level of transcription of the gene and post-translationally at the protein level. Sp1 has emerged as the major driver of expression of the androgen receptor gene, while auto-regulation by androgens is associated with both positive and negative regulation in a possible cell-selective manner. Research into the networks of positive and negative regulators of the androgen receptor gene are vital in order to understand the temporal and spatial control of receptor levels and the consequences for healthy aging and disease. A clear understanding of the multiple transcription factors participating in regulation of the androgen receptor gene will likely aid in the development and application of hormone therapies to boast or curb receptor activity.

Androgen suppresses testicular cancer cell growth in vitro and in vivo

Silencing of androgen receptor (AR)-meditated androgen signaling is thought to be associated with the development of testicular germ cell tumors (TGCTs). However, the role of the androgen/AR signal in TGCT development has not been investigated. In this study, we show that the androgen/AR signal suppressed the cell growth of seminomas (SEs), a type of TGCT, in vitro and in vivo. Growth of SE cells was suppressed by DHT treatment and reduction of androgen levels by surgical castration promoted cancer cell growth in an in vivo xenograft model. Tryptophan hydroxylase 1 (TPH1), the rate limit enzyme in serotonin synthesis, was one of the genes which expression was reduced in DHT-treated SE cells. TPH1 was highly expressed in SE cancer tissues compared with adjacent normal tissues. Activation of androgen/AR signaling in SE cells reduced the expression of TPH1 in SE cells, followed by the reduction of serotonin secretion in cell culture supernatant. These results suggested that silencing of androgen/AR signaling may cause initiation and progression of SE through increase in TPH1 gene expression level.

A hypothetical pathogenesis model for androgenic alopecia: clarifying the dihydrotestosterone paradox and rate-limiting recovery factors

Androgenic alopecia, also known as pattern hair loss, is a chronic progressive condition that affects 80% of men and 50% of women throughout a lifetime. But despite its prevalence and extensive study, a coherent pathology model describing androgenic alopecia's precursors, biological step-processes, and physiological responses does not yet exist. While consensus is that androgenic alopecia is genetic and androgen-mediated by dihydrotestosterone, questions remain regarding dihydrotestosterone's exact role in androgenic alopecia onset. What causes dihydrotestosterone to increase in androgenic alopecia-prone tissues? By which mechanisms does dihydrotestosterone miniaturize androgenic alopecia-prone hair follicles? Why is dihydrotestosterone also associated with hair growth in secondary body and facial hair? Why does castration (which decreases androgen production by 95%) stop pattern hair loss, but not fully reverse it? Is there a relationship between dihydrotestosterone and tissue remodeling observed alongside androgenic alopecia onset? We review evidence supporting and challenging dihydrotestosterone's causal relationship with androgenic alopecia, then propose an evidence-based pathogenesis model that attempts to answer the above questions, account for additionally-suspected androgenic alopecia mediators, identify rate-limiting recovery factors, and elucidate better treatment targets. The hypothesis argues that: (1) chronic scalp tension transmitted from the galea aponeurotica induces an inflammatory response in androgenic alopecia-prone tissues; (2) dihydrotestosterone increases in androgenic alopecia-prone tissues as part of this inflammatory response; and (3) dihydrotestosterone does not directly miniaturize hair follicles. Rather, dihydrotestosterone is a co-mediator of tissue dermal sheath thickening, perifollicular fibrosis, and calcification - three chronic, progressive conditions concomitant with androgenic alopecia progression. These conditions remodel androgenic alopecia-prone tissues - restricting follicle growth space, oxygen, and nutrient supply - leading to the slow, persistent hair follicle miniaturization characterized in androgenic alopecia. If true, this hypothetical model explains the mechanisms by which dihydrotestosterone miniaturizes androgenic alopecia-prone hair follicles, describes a rationale for androgenic alopecia progression and patterning, makes sense of dihydrotestosterone's paradoxical role in hair loss and hair growth, and identifies targets to further improve androgenic alopecia recovery rates: fibrosis, calcification, and chronic scalp tension.

Bone turnover marker determinants in young women: results from the Safe-D study

Background Bone turnover markers (BTMs) may provide insight into bone health in young women, but have been little studied in this demographic. We aimed to explore the association between body composition, hormonal contraception, bone mineral density and biochemical parameters and BTMs in young women. Methods Participants were community-dwelling females aged 16-25 years, living in Victoria, Australia. Carboxy-terminal cross-linking telopeptide of type 1 collagen (CTX) and total procollagen type 1 N-propeptide (P1NP) were analysed on the Roche Elecsys automated analyzer. A total of 305 were evaluated, after excluding participants with medical conditions or medications (except hormonal contraceptives), which may affect bone metabolism. Results Median (Q1, Q3) BTM values were 540 (410, 690) ng/L for CTX and 61.7 (46.2, 83.7) µg/L for P1NP. Serum CTX and P1NP were inversely associated with chronological age ( P < 0.001), transferrin ( P < 0.020) and serum dehydroepiandrosterone sulphate concentration ( P < 0.001). BTM values were up to 22% lower in combined oral contraceptive (COC) pill users ( P < 0.001). Serum CTX was inversely associated with per cent body fat ( P = 0.009) and tibial cortical volumetric bone mineral density (vBMD; P = 0.003). Serum P1NP concentrations were 23  µg/L higher in participants who reported using an osteopath in the previous year ( P = 0.007). Conclusions These data suggest that BTMs are influenced by age, COC use, body composition, iron status and hormonal profiles. Higher CTX values were associated with lower tibial cortical vBMD. Examining BTMs in relation to interventions aimed at improving bone health in young women is warranted.

Dihydrotestosterone, a robust promoter of osteoblastic proliferation and differentiation: understanding of time-mannered and dose-dependent control of bone forming cells

Objective(s):

The present study was aimed to evaluate the time-mannered and dose-dependent effects of 5α-dihydrotestosterone (5α-DHT) on the proliferation and differentiation of bone forming cells using MC3T3-E1 cells.

Materials and Methods:

Cell proliferation was analyzed using MTS and phase contrast microscopic assays. Osteogenic differentiation was assessed through a series of in vitro experiments including crystal violet staining, alkaline phosphatase (ALP) activity, and Van Gieson (VG) staining. Taken together, the efficiency of bone mineralization was examined by using alizarin red s (ARS) staining, Von Kossa staining, scanning electron microscopy (SEM) and energy dispersive x-ray (EDX) analysis.

Results:

The resulting data revealed that 5α-DHT exhibits promising potential particularly at a dose of 0.1 ng/ml, in promoting the growth of MC3T3-E1 cells compared to the control group (CN). Moreover, a significantly higher ALP activity was evident in the experimental group treated with 5α-DHT compared to the CN group at various time intervals. MC3T3-E1 cells treated with 5α-DHT also expressed a remarkably higher collagen deposition and mineralization (calcium and phosphate contents) compared to the CN group at various time intervals.

Conclusion:

Conclusively, we suggest that 5α-DHT exhibits outstanding potential of promoting proliferation and differentiation in osteoblasts which could be the in vitro basis for the efficacy of 5α-DHT in the treatment of androgen-deficient male osteoporosis.

An association between bone mineral density and anabolic hormones in middle-aged and elderly men with prediabetes

INTRODUCTION

Prediabetes (PD) leads to reduced testosterone (T) in males, but the association between the anabolic hormones and bone mineral density (BMD) remains unknown.

OBJECTIVES

We investigated an association between the anabolic hormones and BMD in middle-aged and elderly men with PD.

METHODS

We investigated 84 prediabetic and 56 control men. Total T (TT), calculated free T (cFT), and dehydroepiandrosterone sulfate (DHEAS) were measured, and BMD was assessed using DXA methods.

RESULTS

Patients with PD had lower TT (p < .001), cFT (p < .005), and DHEAS (p < .02) than control group. BMD values of the lower lumbar spine (p < .02) and total body (p < .05) in prediabetic men were lower than in control group. Lumbar spine BMD correlated with TT (r = 0.376), cFT (r = 0.235), and HbA1c (r = -0.368); femoral neck BMD correlated with TT (r = 0.412) and cFT (r = 0.421). The high lumbar spine and femur neck BMD was associated with high TT, cFT, and low HbA1c, while the high total body BMD with high TT, cFT, and low HbA1c.

CONCLUSION

The anabolic hormones significantly affect BMD in male with PD, and screening for low BMD is necessary in these patients.

Guidelines of the Brazilian Society of Rheumatology for the diagnosis and treatment of osteoporosis in men

Osteoporosis, a metabolic disease characterized by low bone mass, deterioration of the bone tissue microarchitecture and increased susceptibility to fractures, is commonly regarded as a women's health problem. This point of view is based on the fact that compared with men, women have lower bone mineral density and longer lifespans and lose bone mass faster, especially after menopause, due to a marked decrease in serum estrogen levels. However, in the last 20 years, osteoporosis in men has become recognized as a public health problem due to the occurrence of an increasingly higher number of fragility fractures. Approximately 30% of all hip fractures occur in men. Recent studies show that the probability of fracture due to hip, vertebral or wrist fragility in Caucasian men older than fifty years, for the rest of their lives, is approximately 13% versus a 40% probability of fragility fractures in women. Men show bone mass loss and fractures later than women. Although older men have a higher risk of fracture, approximately half of all hip fractures occur before the age of 80. Life expectancy is increasing for both sexes in Brazil and worldwide, albeit at a higher rate for men than for women. This Guideline was based on a systematic review of the literature on the prevalence, etiology, diagnosis and treatment of osteoporosis in men.

Androgen supplementation improves some but not all aspects of immune senescence in aged male macaques

Aging leads to a progressive decline in immune function commonly referred to as immune senescence, which results in increased incidence and severity of infection. In addition, older males experience a significant disruption in their levels of circulating androgens, notably testosterone and dehydroepiandrosterone (DHEA), which has been linked to sarcopenia, osteoporosis, cardiovascular disease, and diabetes. Since sex steroid levels modulate immune function, it is possible that the age-related decline in androgen levels can also affect immune senescence. Therefore, in this study, we evaluated the pleiotropic effects of physiological androgen supplementation in aged male rhesus macaques (n = 7/group) on immune cell subset frequency and response to vaccination. As expected, frequency of naïve CD4 and CD8 T cells declined in aged non-treated macaques, while that of memory T cells increased. In contrast, frequency of naïve and memory T cells remained stable in androgen-supplemented males. In addition, levels of inflammatory cytokines increased less steeply in supplemented aged males compared to the aged controls. Despite these changes, androgen-supplemented animals only showed modest improvement in antibody responses following vaccination compared to age non-treated controls. These data indicate that short-term physiological androgen supplementation can improve some but not all aspects of immune senescence.

Effects of Adrenal Androgen Levels on Bone Age Advancement in Prepubertal Children: Using the Ewha Birth and Growth Cohort Study

Bone age (BA) advancement in prepubertal children may be associated with earlier onset of puberty and obesity. This study aimed to define the effects of adrenal androgen levels on the advancement of BA in prepubertal children, independent of obesity. During July and August 2011, we examined BA in 200 prepubertal children aged 7-9 years who were part of the Ewha Birth & Growth Cohort Study. BA was assessed by the Greulich-Pyle method. An index of BA advancement was calculated as the ratio of BA to chronological age (CA) (BA/CA), and this ratio was classified into 3 tertiles. We analyzed the relationship between BA advancement and anthropometric characteristics and adrenal hormone levels. The number of overweight children increased from the first group to the third group (P(Trend) = 0.03). The levels of adrenal androgens showed a significant positive correlation with the tertile groups after adjusting for age and sex (testosterone: r = 0.26, P < 0.001; dehydroepiandrosterone: r = 0.21, P < 0.001; androstenedione: r = 0.20, P < 0.001). Further, after controlling for body mass index (BMI), sex, and age, the BA/CA was found to be positively correlated with androstenedione (β = 0.04, R² = 3.7%) and testosterone levels (β = 0.05, R² = 4.7%). Based on our results, it is suggested that adrenal androgen levels are associated with BA advancement independent of BMI.

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.