Sex hormones and bone health in males

The importance of association between sexsteroids deficiency, reduction of bone mineral density and falling risk in men with implications in medical rehabilitation

Introduction. Endocrino-metabolic rehabilitation represent one of the most complex sector in clinical medicine, regarding functional rehabilitation. Sex hormones deficiency plays an important role in the etiology of osteoporosis in men. At the same time, with age, the trophic role of androgens on muscle decreases and determines an increased frequency of falls. The objective of our study is to determine the association between sexsteroids deficiency, reduction of bone mineral density (BMD) and falling risk in men. Methods. Our retrospective cross-sectional study included 146 men aged between 65–85 years with low BMD (study group) and 121 men with normal BMD (control group). The measurement of Total testosterone (Tt), free testosterone (Tf) and estradiol (E2) serum levels was performed using the immunoassay or the immunoenzymatic methods. Femoral neck and lumbar spine BMD was determined using Dual-energy X-ray absorptiometry (DEXA). The risk of falls was assessed by Tandem Standing, Up & Go, Chair – Rising and walking speed tests. Results. We found a significantly association between Tf and E2 deficiency and low BMD (p=0.007). Also, in men with reduced BMD (study group) we observed significant lower levels of Tf (p<0.001) and E2 (p=0.003) compared to control group. E2 deficiency was associated significantly with low BMD and increased fall risk (p=0.001). At the same time the results highlighted significant lower levels of Tf in patients with BMD reduction and increased risk of falls (p=0.002). Tt deficiency was not associated with BMD reduction (p=0.088) or increased risk of falling (p=0.277). Conclusions. This research revealed a significant association between male sexsteroids deficiency, low BMD and increase of falling risk, with implications in rehabilitation program. The risk of ostoporosis and for falling in man can be estimated by determining serum Tf and E2 levels. Keywords: sexsteroids deficiency; bone mineral density; falling risk,

Morphology and serum and bone tissue calcium and magnesium concentrations in the bones of male rats chronically treated with letrozole, a nonsteroidal cytochrome P450 aromatase inhibitor

Purpose/Aim of the study: The role of estrogen (E) in the regulation of bone turnover in women is well established, though the contributions of E versus testosterone (T) in the control of bone turnover in men are poorly understood. The aim of this study was to examine the association between chronic treatment with letrozole, a nonsteroidal inhibitor blocking the aromatase activity and thus the conversion of androgens into estrogens, and cortical bone morphology in the femur and humerus of male adult rats.Materials and Methods: Adult male rats were treated with letrozole for 6 months and the body and femur weight, morphology, collagen structure, blood serum, and bone tissue concentrations of calcium and magnesium were examined.Results: Long-term aromatase inhibition resulted in a decrease in femur mass, a wavelike arrangement of bone and lamellae with an altered organization of collagen in compact bone, a increased concentration of calcium in blood serum, and no change in calcium bone tissue concentration, magnesium serum, or bone tissue concentration. MicroCT study of the humerus revealed significant decreases of whole bone tissue volume, cortical bone thickness, cortical bone volume, and external cortical bone thickness with letrozole treatment.Conclusion: Chronic treatment with letrozole affected cortical bone structure and produced histomorphological changes in male rat bone similar to that observed in the aging processes.

Bone Health in Aging Men: Does Zinc and Cuprum Level Matter?

The aim of this study was to assess the associations of serum and bone zinc (Zn) and cuprum (Cu) with bone mineral density (BMD) and content (BMC), markers of bone turnover, and sex hormones. The study group comprised 144 men treated with total hip replacement due to hip osteoarthritis. We measured total, free, and bioavailable testosterone, estradiol, and sex-hormone-binding globulin (sex hormones), as well as parathyroid hormone, osteocalcin, carboxy terminal collagen crosslinks, and N-terminal propeptide of type I procollagen (markers of bone turnover). Total body BMD, BMC, total and visceral fat, and appendicular skeletal mass (ASM) were measured using dual-energy X-ray absorptiometry. ASM index, and total and visceral fat were positively correlated with BMD. Bone Zn correlated neither with sex hormones nor with bone turnover markers; however, it was positively associated both with BMD and with BMC, while bone Cu (as opposed to serum Cu) was not. In multiple regression, the ASM index, Zn/Cu ratio (in both the serum and the bone), and serum Cu concentration were significantly associated with BMD and BMC after adjustment for age and body mass index (BMI). Our results suggest that the Zn/Cu ratio in both the serum and the bone may exert a significant positive effect on total BMD and BMC.

Association between Serum Testosterone Levels and Body Composition among Men 20-59 Years of Age

INTRODUCTION

Sex hormones play an important role in the development and maintenance of bone and muscle mass. However, studies regarding serum testosterone levels, osteoporosis, and sarcopenia in men are relatively sparse and have led to contradictory conclusions. Therefore, this study aimed to investigate the association between serum testosterone levels and body composition, including bone mineral density (BMD), appendicular lean mass index (ALMI), and appendicular fat mass index (AFMI), among men 20-59 years of age through a cross-sectional analysis of the National Health and Nutrition Examination Survey.

MATERIALS AND METHODS

Our analysis was based on the data for 3,875 men, 20-59 years of age. Weighted multiple regression analyses were used to estimate the independent association between serum testosterone levels and body composition. Weighted generalized additive models and smooth curve fittings were used to characterize the nonlinear associations between them.

RESULTS

The association between the serum testosterone level and lumbar BMD was positive in each multivariable linear regression model. In the model adjusted for age and race, the serum testosterone level was negatively associated with ALMI. However, in the models adjusted for body mass index, this association became positive. In addition, the association between the serum testosterone level and AFMI was negative in each multivariable linear regression model.

CONCLUSION

Our study demonstrated a positive association of serum testosterone level with lumbar BMD and ALMI, and a negative association with AFMI, among men 20-59 years of age, suggesting that increasing testosterone levels may be beneficial to skeletal health in young and middle-aged men with low testosterone levels.

Association of Serum Testosterone at 12 Years with a Subsequent Increase in Bone Mineral Apparent Density at 18 Years: A Longitudinal Study of Boys in Puberty

BACKGROUND

Cross-sectional studies have associated serum testosterone with bone mineral density (BMD). However, there is a shortage of prospective longitudinal studies in this domain, leaving it unclear whether changes in testosterone level precede changes in BMD.

OBJECTIVES

To examine the association between serum testosterone concentration at the age of 12 years and a subsequent increase in BMD by the age of 18 years.

METHODS

Eighty-eight boys with a mean age of 12.1 ± 0.7 (time point 1 [T1]) and 18.0 ± 0.7 (T2) were investigated. For both time points, serum testosterone was measured from venous blood samples. Total body (TB) and lumbar spine (LS) BMD and bone mineral apparent density (BMAD) were measured. As different brands of DEXA machines were used at T1 and T2, we calculated SD scores (SDS) from samples at T1 and T2 and their change (Δ). As covariates, bone age at T1 and physical activity (PA) by accelerometer at T1 and T2 were measured.

RESULTS

Serum testosterone at T1 was positively correlated with TB BMD at T2 (r = 0.28; p < 0.01), Δ TB BMAD SDS (r = 0.47; p < 0.0001) and Δ LS BMAD SDS (r = 0.23; p < 0.05). When additionally controlling for bone age and total PA at T1, the correlation between testosterone at T1 and Δ TB BMAD SDS remained significant (r = 0.32; p < 0.05).

CONCLUSIONS

Serum testosterone concentration at the age of 12 years is associated with a subsequent increase in TB BMAD by the age of 18 years. This supports the inference that testosterone levels in early puberty may influence subsequent bone mineral accrual.

The effect of testosterone itself and in combination with letrozole on bone mineral density in male rats

Testosterone is an essential hormone to maintain bone integrity; however, the effect of aromatase enzyme in androgen-induced bone maintenance remains somewhat unclear. The present study evaluated the effect of testosterone itself and combined with letrozole, an aromatase inhibitor, on bone mineral density of male rats. Total of 48 male rats were divided into 4 equal groups (n = 12/group); sham group, O: orchiectomy, O + T: orchiectomized rats treated with testosterone, O + T + L: orchiectomized rats treated with combination of testosterone and letrozole. Bone density (BMD), bone markers, and vitamin D metabolism parameters were checked in all groups before and after the study. There was no significant difference in baseline values of these parameters, but at the end of the study there was a significant decrease in delta BMD at both lumbar and femor in orchiectomized rats in comparison with the sham group (p < 0.001, p < 0.001, respectively). Both testosterone and its combination with letrozole increased lumbar and femoral BMD of orchiectomized rats, with a higher increase in lumbar BMD in O + T group. CTX were higher in O group rats. The present study showed a major role for testosterone on BMD maintenance in male rats. However, testosterone has a potent effect on lumbar BMD, by the aromatization to estradiol.

Cancer Treatment and Bone Health

Considerable advances in oncology over recent decades have led to improved survival, while raising concerns about long-term consequences of anticancer treatments. In patients with breast or prostate malignancies, bone health is a major issue due to the high risk of bone metastases and the frequent prolonged use of hormone therapies that alter physiological bone turnover, leading to increased fracture risk. Thus, the onset of cancer treatment-induced bone loss (CTIBL) should be considered by clinicians and recent guidelines should be routinely applied to these patients. In particular, baseline and periodic follow-up evaluations of bone health parameters enable the identification of patients at high risk of osteoporosis and fractures, which can be prevented by the use of bone-targeting agents (BTAs), calcium and vitamin D supplementation and modifications of lifestyle. This review will focus upon the pathophysiology of breast and prostate cancer treatment-induced bone loss and the most recent evidence about effective preventive and therapeutic strategies.

Effect of risedronate in osteoporotic HIV males, according to gonadal status: a pilot study

The aim of the study was to evaluate the effect of risedronate on bone mineral density (BMD) and bone turnover markers in HIV-infected osteoporotic males, according to their gonadal status. HIV patients were followed up for 24 months and divided into two groups: patients with osteoporosis or osteopenia with fractures (group A, n = 20) and those without (group B, n = 21). Group A and B were further divided according to the presence of reduced androgenizations. Both groups were treated with cholecalciferol 800 I.U. and calcium (Ca) 1,000 mg orally every day for the first 12 months. Risedronate 75 mg for two consecutive days a month orally was then added in group A, for another 12 months. Group B continued treatment with Ca and vitamin D. Every 6 months each patient underwent biochemical evaluation, and BMD measurement. A significant increase in lumbar BMD was observed in HIV males with adequate androgenization after 12 months of risedronate treatment in group A together with a reduction of bone turnover markers. BMD remained stable with a concomitant significant slight reduction of bone turnover markers in group B. Risedronate increased BMD and reduced bone turnover markers to a greater extent in patients with adequate androgenization compared to osteoporotic HIV males with symptomatic hypoandrogenization.

Effects of testosterone replacement therapy on bone metabolism in male post-surgical hypogonadotropic hypogonadism: focus on the role of androgen receptor CAG polymorphism

INTRODUCTION AND AIM

The relationship between androgen receptor (AR) CAG polymorphism and bone metabolism is highly controversial. We, therefore, aimed to evaluate the independent role of AR CAG repeat polymorphism on bone metabolism improvement induced by testosterone replacement therapy (TRT) in male post-surgical hypogonadotropic hypogonadism, a condition frequently associated with hypopituitarism and in which the effects of TRT have to be distinguished from those resulting from concomitant administration of pituitary function replacing hormones.

METHODS

12 men affected by post-surgical hypogonadotropic hypogonadism [mean duration of hypogonadism 8.3 ± 2.05 (SD) months] were retrospectively assessed before and after TRT (from 74 to 84 weeks after the beginning of therapy). The following measures were studied: parameters of bone metabolism [serum markers and bone mineral density (BMD)], pituitary dependent hormones and genetic analysis (AR CAG repeat number).

RESULTS

Total testosterone, estradiol, free T4 (FT4) and insulin-like growth factor-1 (IGF-1) increased between the two phases, while follicle stimulating hormone (FSH) decreased. While serum markers did not vary significantly between the two phases, BMD improved slightly but significantly in all the studied sites. The number of CAG triplets correlated negatively and significantly with all the variations (Δ-) of BMDs. Conversely, Δ-testosterone correlated positively and significantly with all studied Δ-BMDs, while Δ-FSH, Δ-estradiol, Δ-FT4, and Δ-IGF-1 did not correlate significantly with any of the Δ-BMDs. Multiple linear regression analysis, after correction for Δ-testosterone, showed that CAG repeat length was negatively and significantly associated with ∆-BMD of all measured sites.

CONCLUSIONS

Our data suggest that, in post-surgical male hypogonadotropic hypogonadism, shorter AR CAG tract is independently associated with greater TRT-induced improvement of BMD.

Bone and mineral metabolism in patients undergoing Roux-en-Y gastric bypass

Despite effective weight reduction, the impact of bariatric surgery on bone is a major concern. Mechanisms include decreased mechanical loading, calcium and vitamin D malabsorption, deficiency in other nutrients, and alterations in fat- and gut-derived hormones. The evidence to support clinical care pathways to prevent bone loss and fractures is at this point weak.

INTRODUCTION

There is a growing concern regarding the potential deleterious impact of bariatric surgery on bone metabolism. This comprehensive review addresses this controversial topic.

METHODS

We reviewed and analyzed articles evaluating bone metabolism and mechanisms for the ensuing putative bone loss in adult patients exclusively undergoing Roux-en-Y gastric bypass (RYGB) surgery, for the period spanning 1942 till September 2012.

RESULTS

Mechanisms identified to contribute to alterations in bone metabolism after bypass surgery include: decreased mechanical loading, calcium and vitamin D malabsorption with secondary hyperparathyroidism, deficiency in other nutrients, in addition to alterations in adipokines, gonadal steroids, and gut-derived hormones favoring bone loss, with the exception of serotonin and glucagon-like peptide-1. The relative contribution of each of these hormones to changes in bone homeostasis after bypass surgery remains undefined. Bone loss reflected by a decline in bone mineral density (BMD) and an increase in bone turnover markers have been reported in many studies, limited for the most part by the exclusive use of dual energy X-ray absorptiometry. Well-designed long-term prospective trials with fractures as an outcome, and studies investigating the magnitude, reversibility, and impact of the observed metabolic changes on fracture outcomes are lacking.

CONCLUSION

Robust conclusions regarding bone loss and fracture outcome after RYGB surgery cannot be drawn at this time. Although not evidence based, baseline evaluation and sequential monitoring with measurement of BMD and calciotropic hormones seem appropriate, with adequate calcium and vitamin D replacement. Beneficial interventions remain unclear.

Control of voice gender in pre-pubertal children

Adult listeners are capable of identifying the gender of speakers as young as 4 years old from their voice. In the absence of a clear anatomical dimorphism in the dimensions of pre-pubertal boys' and girls' vocal apparatus, the observed gender differences may reflect children's regulation of their vocal behaviour. A detailed acoustic analysis was conducted of the utterances of 34 6- to 9-year-old children, in their normal voices and also when asked explicitly to speak like a boy or a girl. Results showed statistically significant shifts in fundamental and formant frequency values towards those expected from the sex dimorphism in adult voices. Directions for future research on the role of vocal behaviours in pre-pubertal children's expression of gender are considered.

Expression of the aryl hydrocarbon receptor pathway and cyclooxygenase-2 in dog tumors

In humans, the aryl hydrocarbon receptor (AHR) gene battery constitutes a set of contaminant-responsive genes, which have been recently shown to be involved in the regulation of several patho-physiological conditions, including tumorigenesis. As the domestic dog represents a valuable animal model in comparative oncology, mRNA levels of cytochromes P450 1A1, 1A2 and 1B1 (CYP1A1, 1A2 and 1B1), AHR, AHR nuclear translocator (ARNT), AHR repressor (AHRR, whose partial sequence was here obtained) and cyclooxygenase-2 (COX2) were measured in dog control tissues (liver, skin, mammary gland and bone), in 47 mast cell tumors (MCTs), 32 mammary tumors (MTs), 5 osteosarcoma (OSA) and related surgical margins. Target genes were constitutively expressed in the dog, confirming the available human data. Furthermore, their pattern of expression in tumor biopsies was comparable to that already described in a variety of human cancers; in particular, both AHR and COX2 genes were up-regulated and positively correlated, while CYP1A1 and CYP1A2 mRNAs were generally poorly expressed. This work demonstrated for the first time that target mRNAs are expressed in neoplastic tissues of dogs, thereby increasing the knowledge about dog cancer biology and confirming this species as an useful animal model for comparative studies on human oncology.

Recent developments in antiandrogens and selective androgen receptor modulators

The androgens testosterone and dihydrotestosterone play an essential role in the development and maintenance of primary and secondary male characteristics. Androgens bind to a specific androgen receptor (AR), a ligand-dependent transcription factor which controls the expression of a large number of downstream target genes. The AR is an essential player in early and late prostate cancer, and may also be involved in some forms of breast cancer. It also represents a drug target for the treatment of hypogonadism. Recent studies furthermore indicate that targeting the AR in pathologies such as frailty syndrome, cachexia or polycystic ovary syndrome may have clinical benefit. Numerous AR ligands with very different pharmacological properties have been identified in the last 40 years and helped to treat several of these diseases. However, progress still needs to be made in order to find compounds with an improved profile with regard to efficacy, differentiation and side-effects. This will only be achieved through a better understanding of the mechanisms involved in normal and aberrant AR signaling.

The relationship between sex steroids, bone turnover and vertebral fracture prevalence in asymptomatic men

OBJECTIVE

To examine the association between oestradiol (E2), testosterone (T), SHBG levels and vertebral fractures' (VFs) prevalence in asymptomatic men.

METHODS

The study cohort consists of a population of 112 consecutive men (mean±SD (range) age, weight and BMI were 62.9±9.2 (41-84) years, 75.0±13.8 (45-120) kgs and 26.4±4.7 (18.0-39.6) kg/m(2), respectively). Lateral vertebral fracture assessment (VFA) images and scans of the lumbar spine and proximal femur were obtained using a GE Healthcare Lunar Prodigy densitometer. VFs were defined using a combination of Genant semiquantitative approach and morphometry. Serum levels of T, E2, CTx and osteocalcine were measured. Free androgen index (FAI) and free estradiol index (FEI) were calculated respectively from the ratio of serum T and E2 to SHBG.

RESULTS

Among the 112 men, 38 (33.9%) had densitometric osteoporosis, and on VFA, VFs were identified in 60 (53.5%): 24 men had grade 1 and 36 had grade 2 or 3 VFs (32.1%). Men with VFs weighted less and had a statistically significant lower lumbar spine and total hip BMD and T-scores than those without a VFA-identified vertebral fracture. Levels of osteocalcine, CTx, and SHBG were statistically higher in men with grades 2 and 3 VFs than men with grade 1 VFs and those without VFs whereas FAI and FEI levels were significantly lower. Comparison of patients according to quartiles of SHBG levels showed that men in the highest quartile were older, had a lower lumbar spine and total hip BMD and a higher prevalence of osteoporosis and VFs. They had also higher levels of CTx. Stepwise regression analysis showed that the osteoporotic status and SHBG was independently associated to the presence of VFs.

CONCLUSION

Men with asymptomatic densitometric VFs have lower BMD than subjects without VFs. They have evidence of higher SHBG levels and hence lower free sex steroids as well as increased bone resorption. This study confirms that BMD and CTx are the most important determinant of asymptomatic VFs, and that SHBG is an independent risk factor that must be taken into account.

Bone vs. fat: embryonic origin of progenitors determines response to androgen in adipocytes and osteoblasts

Although androgen is considered an anabolic hormone, the consequences of androgen receptor (AR) overexpression in skeletally-targeted AR-transgenic lines highlight the detrimental effect of enhanced androgen sensitivity on cortical bone quality. A compartment-specific anabolic response is observed only in male and not in female AR3.6-transgenic (tg) mice, with increased periosteal bone formation and calvarial thickening. To identify anabolic signaling cascades that have the potential to increase bone formation, qPCR array analysis was employed to define expression differences between AR3.6-tg and wild-type (WT) periosteal tissue. Notably, categories that were significantly different between the two genotypes included axonal guidance, CNS development and negative regulation of Wnt signaling with a node centered on stem cell pathways. Further, fine mapping of AR3.6-tg calvaria revealed that anabolic thickening in vivo is not uniform across the calvaria, occurring only in frontal and in not parietal bones. Multipotent fraction 1 progenitor populations from both genotypes were cultured separately as frontal bone neural crest stem-like cells (fNCSC) and parietal bone mesenchymal stem-like cells (pMSC). Both osteoblastic and adipogenic differentiation in these progenitor populations was influenced by embryonic lineage and by genotype. Adipogenesis was enhanced in WT fNCSC compared to pMSC, but transgenic cultures showed strong suppression of lipid accumulation only in fNCSC cells. Osteoblastogenesis was significantly increased in transgenic fNCSC cultures compared to WT, with elevated alkaline phosphatase (ALP) activity and induction of mineralization and nodule formation assessed by alizarin red and von Kossa staining. Osteocalcin (OC) and ALP mRNA levels were also increased in fNCSC cultures from AR3.6-tg vs. WT, but in pMSC cultures ALP mRNA levels, mineralization and nodule formation were decreased in AR3.6-tg cells. Expression differences identified by array in long bone periosteal tissue from AR3.6-tg vs. WT were recapitulated in the fNCSC samples while pMSC profiles reflected cortical expression. These observations reveal the opposing effects of androgen signaling on lineage commitment and osteoblast differentiation that is enhanced in cells derived from a neural crest origin but inhibited in cells derived from a mesodermal origin, consistent with in vivo compartment-specific responses to androgen. Combined, these results highlight the complex action of androgen in the body that is dependent on the embryonic lineage and developmental origin of the cell. Further, these data these data suggest that the periosteum surrounding long bone is derived from neural crest.

Secondary osteoporosis in men and women: clinical challenge of an unresolved issue

OBJECTIVE

To evaluate the clinical and etiological factors of osteoporosis. We also tested the FRAX algorithm to compare the assessment of fracture risk in patients with primary or secondary osteoporosis.

METHODS

A prospective study carried out in a large sample of 123 men and 246 women. All subjects had a biochemical, densitometric, and radiological examination of thoracic and lumbar spine.

RESULTS

The prevalence of primary (men 52.9% vs women 50%; p = nonsignificant) and secondary (men 21.1% vs women 17.5%; p = nonsignificant) osteoporosis did not differ between the sexes. In contrast, the prevalence of primary osteoporosis was significantly higher than secondary causes (p < 0.0001) in both men and women. While women came to our attention for prevention of osteoporosis, men sought help because of clinical symptoms or disease-related complications, such as fractures. As evaluated by the FRAX tool, patients with osteopenia do not need treatment, in agreement with Italian guidelines. The estimated risk of major osteoporotic and hip fractures was significantly higher in women with secondary osteoporosis compared to men and also compared to women with primary osteoporosis.

CONCLUSION

The prevalence of secondary osteoporosis in men is similar to that in women and it is less frequent than commonly reported. In patients with secondary osteoporosis, FRAX calculation may provide an estimate of a particularly high fracture risk in patients whose bone fragility is usually attributed to another disease.