Osteoporosis in older men: recent advances in pathophysiology and treatment

Sex differences in systemic bone and muscle loss following femur fracture in mice

Fracture induces systemic bone loss in mice and humans, and a first (index) fracture increases the risk of future fracture at any skeletal site more in men than women. The etiology of this sex difference is unknown, but fracture may induces a greater systemic bone loss response in men. Also sex differences in systemic muscle loss after fracture have not been examined. We investigated sex differences in systemic bone and muscle loss after transverse femur fracture in 3-month-old male and female C57BL/6 J mice. Whole-body and regional bone mineral content and density (BMC and BMD), trabecular and cortical bone microstructure, muscle contractile force, muscle mass, and muscle fiber size were quantified at multiple time points postfracture. Serum concentrations of inflammatory cytokines (IL-1β, IL-6, and TNF-α) were measured 1-day postfracture. One day postfracture, IL-6 and Il-1B were elevated in fracture mice of both sexes, but TNF-α was only elevated in male fracture mice. Fracture reduced BMC, BMD, and trabecular bone microstructural properties in both sexes 2 weeks postfracture, but declines were greater in males. Muscle contractile force, mass, and fiber size decreased primarily in the fractured limb at 2 weeks postfracture and females showed a trend toward greater muscle loss. Bone and muscle properties recovered by 6 weeks postfracture. Overall, postfracture systemic bone loss is greater in men, which may contribute to sex differences in subsequent fracture risk. In both sexes, muscle loss is primarily confined to the injured limb and fracture may induce greater inflammation in males.

Osteoporosis: A Step-by-Step Case-Based Study

Osteoporosis is a common disease that affects our elderly population. This disease usually gets undiagnosed for an extended period. Osteoporosis increases the risk of fracture in our elderly population and increases morbidity. The cost associated with osteoporosis does carry a substantial burden in our society. Here, we present a case of osteoporosis with a fracture diagnosed in clinical settings. We discuss different etiology, pathophysiology, and treatment options available to treat this medical condition.

Androgen Misuse and Abuse

Androgens are potent drugs requiring prescription for valid medical indications but are misused for invalid, unproven, or off-label reasons as well as being abused without prescription for illicit nonmedical application for performance or image enhancement. Following discovery and first clinical application of testosterone in the 1930s, commercialization of testosterone and synthetic androgens proliferated in the decades after World War II. It remains among the oldest marketed drugs in therapeutic use, yet after 8 decades of clinical use, the sole unequivocal indication for testosterone remains in replacement therapy for pathological hypogonadism, organic disorders of the male reproductive system. Nevertheless, wider claims assert unproven, unsafe, or implausible benefits for testosterone, mostly representing wishful thinking about rejuvenation. Over recent decades, this created an epidemic of testosterone misuse involving prescription as a revitalizing tonic for anti-aging, sexual dysfunction and/or obesity, where efficacy and safety remains unproven and doubtful. Androgen abuse originated during the Cold War as an epidemic of androgen doping among elite athletes for performance enhancement before the 1980s when it crossed over into the general community to become an endemic variant of drug abuse in sufficiently affluent communities that support an illicit drug industry geared to bodybuilding and aiming to create a hypermasculine body physique and image. This review focuses on the misuse of testosterone, defined as prescribing without valid clinical indications, and abuse of testosterone or synthetic androgens (androgen abuse), defined as the illicit use of androgens without prescription or valid indications, typically by athletes, bodybuilders and others for image-oriented, cosmetic, or occupational reasons.

MiR-133a delivery to osteoblasts ameliorates mechanical unloading-triggered osteopenia progression in vitro and in vivo

Mechanical unloading-induced bone loss is a clinical challenge, and deep understanding for this disease is necessary for developing novel and effective therapies. MicroRNAs (miRNAs) are small non-coding RNAs, and involved in bone remodeling. In the study, we attempted to explore the potential of miR-133a in regulating osteoblast activation and its anti-osteopenia function both in vitro and in vivo. Our in vitro studies at first showed that miR-133a could significantly promote the expression of osteocalcin (OCN), Collagen I, alkaline phosphatase (ALP), runt-related transcription factor 2 (Runx2) and osterix (Osx), promoting the activation and mineralization of osteoblasts. Then, hindlimb unloading (HU)-challenged mice were established with or without intravenous injection of agomir-miR-133a using an osteoblast-targeting delivery system. We found that miR-133a in osteoblasts significantly alleviated the bone loss, microstructural, and biomechanical property in mice with mechanical unloading, contributing to osteopenia alleviation. Furthermore, both in vitro and in vivo experiments showed that miR-133a could restrain osteoclastogenesis via tartrate-resistant acid phosphatase (TRAP) staining. In conclusion, our results suggested that miR-133a may be a promising factor in mediating the occurrence and progression of osteopenia caused by mechanical unloading, and thus targeting miR-133a could be considered as an effective therapeutic strategy for the suppression of pathological osteopenia.

Prognostic performance of Predictive Index for Osteoporosis and Osteoporosis Self-Assessment Tool for Asians in the identification of individuals high-risk for osteoporosis

Objectives

To compare Predictive Index for Osteoporosis (PIO) with Osteoporosis Self-Assessment Tool for Asians (OSTA) as a clinical tool for identifying the risk of osteoporosis in Filipino men 50–69 and Filipino women 50–65 years of age.

Methods

This was an analytic study that employed a cross sectional approach that included Filipino men and women seen at the Outpatient Charity Department or at the private clinics and who underwent dual energy X-ray absorptiometry. All subjects completed a structured questionnaire and their weight and height were obtained, from which their PIO and OSTA scores were computed.

Results

A total of 81 patients were included in the study. OSTA has an area under the curve of 0.712 which turns out to be significant (P = 0.0004), with a calculated likelihood ratio of 1.64. The receiver operating characteristic (ROC) curve of PIO showed that the optimal cut off is > 0.962 and the calculated likelihood ratio that this patient may have osteoporosis is 1.38. Comparing the sensitivity and specificity, the resulting P value of 0.2728 denotes that the area under the curve of the 2 tools is not significantly different.

Conclusions

The optimal cut-off point of OSTA and PIO to discriminate high-risk and low-risk patients for osteoporosis were 0.712 and 0.686, respectively, based on ROC analysis. The performance measures of OSTA and PIO did not vary significantly in predicting the risk for osteoporosis in Filipino adults.

Activation of FoxO1/SIRT1/RANKL/OPG pathway may underlie the therapeutic effects of resveratrol on aging-dependent male osteoporosis

Background

Age-dependent male osteoporosis remains a poorly studied medical problem despite its significance. It is estimated that at least 1 of 5 men will suffer from osteoporotic consequences. Given that multiple mechanisms are involved in the process of senescence, much attention has been given to compounds with polymodal actions. To challenge such a health problem, we tested here the therapeutic potential of resveratrol in male osteoporosis. We also studied the possible molecular mechanisms that may underlie resveratrol effects.

Methods

Thirty male Wistar albino rats were used in the present study. Rats were divided (10/group) into: control (3–4 months old weighing 150–200 g receiving vehicle), aged (18–20 months old, weighing 350–400 g and receiving vehicle), and resveratrol treated aged (18–20 months old, weighing 350–400 g and receiving resveratrol 20 mg/kg/day for 6 weeks) groups. Assessment of serum calcium, phosphate, bone specific alkaline phosphatase, inflammatory cytokines, oxidative stress markers, and rat femur gene expression of FoxO1, SIRT1, RANKL and OPG proteins was carried out. Histopathological assessment of different levels of rat femur was also performed.

Results

Age-dependent osteoporosis resulted in significant increase in serum levels of phosphate, bone specific alkaline phosphatase, hsCRP, IL-1β, IL-6, TNF-α, MDA, NO, and RANKL gene expression. However, there was significant decrease in serum level of GSH, and gene expression of FoxO1, SIRT1 and OPG. Osteoporotic changes were seen in femur epiphysis, metaphysis and diaphysis. Resveratrol restored significantly age-dependent osteoporotic changes.

Conclusion

We concluded that resveratrol can play an important role in the prevention of male osteoporosis. Resveratrol can counter the molecular changes in male osteoporosis via anti-inflammatory, anti-oxidant and gene modifying effects.

Abaloparatide improves cortical geometry and trabecular microarchitecture and increases vertebral and femoral neck strength in a rat model of male osteoporosis

Androgen deficiency is a leading cause of male osteoporosis, with bone loss driven by an inadequate level of bone formation relative to the extent of bone resorption. Abaloparatide, an osteoanabolic PTH receptor agonist used to treat women with postmenopausal osteoporosis at high risk for fracture, increases bone formation and bone strength in estrogen-deficient animals without increasing bone resorption. This study examined the effects of abaloparatide on bone formation, bone mass, and bone strength in androgen-deficient orchiectomized (ORX) rats, a male osteoporosis model. Four-month-old Sprague-Dawley rats underwent ORX or sham surgery. Eight weeks later, sham-operated rats received vehicle (saline; n = 10) while ORX rats (n = 10/group) received vehicle (Veh) or abaloparatide at 5 or 25 μg/kg (ABL5 or ABL25) by daily s.c. injection for 8 weeks, followed by sacrifice. Dynamic bone histomorphometry indicated that the tibial diaphysis of one or both abaloparatide groups had higher periosteal mineralizing surface, intracortical bone formation rate (BFR), endocortical BFR, and cortical thickness vs Veh controls. Vertebral trabecular BFR was also higher in both abaloparatide groups vs Veh, and the ABL25 group had higher trabecular osteoblast surface without increased osteoclast surface. By micro-CT, the vertebra and distal femur of both abaloparatide-groups had improved trabecular bone volume and micro-architecture, and the femur diaphysis of the ABL25 group had greater cortical thickness with no increase in porosity vs Veh. Biomechanical testing indicated that both abaloparatide-groups had stronger vertebrae and femoral necks vs Veh controls. These findings provide preclinical support for evaluating abaloparatide as an investigational treatment for male osteoporosis.

Abaloparatide, a novel osteoanabolic PTHrP analog, increases cortical and trabecular bone mass and architecture in orchiectomized rats by increasing bone formation without increasing bone resorption

Male osteoporosis can occur with advanced age and with hypogonadism, with increased bone resorption and/or inadequate bone formation contributing to reduced bone mass and increased fracture risk. Abaloparatide is a selective PTH receptor agonist that increases bone formation and bone mass in postmenopausal women with osteoporosis and in estrogen-deficient animals. The current study evaluated the effects of abaloparatide in orchiectomized (ORX) rats, a model of male osteoporosis. Four-month-old Sprague-Dawley rats underwent ORX or sham surgery; 8 weeks later the ORX groups exhibited relative osteopenia vs sham controls, based on dual X-ray absorptiometry (DXA) and/or peripheral quantitative computed tomography (pQCT) assessments at the total body, lumbar spine, femur, and tibia. ORX rats (n = 10/group) were then injected daily (s.c.) for 8 weeks with vehicle or abaloparatide at 5 (ABL5) or 25 μg/kg/d (ABL25). Sham controls (n = 10) received s.c. vehicle. DXA and pQCT showed that one or both abaloparatide groups gained more areal and volumetric BMD at all sites analyzed compared with vehicle controls, leading to substantial or complete reversal of ORX-induced BMD deficits. pQCT also indicated greater gains in tibial cortical thickness in both abaloparatide groups versus vehicle controls. Tibial bone histomorphometry showed greater trabecular bone formation and bone volume and improved micro-architecture with abaloparatide, with no increase in osteoclasts. Abaloparatide also led to significant improvements in the balance of biochemical bone formation markers versus bone resorption markers, which correlated with BMD changes. These findings suggest that abaloparatide may have therapeutic benefits in men with osteoporosis.

Osteoblast-targeted delivery of miR-33-5p attenuates osteopenia development induced by mechanical unloading in mice

A growing body of evidence has revealed that microRNAs (miRNAs) play crucial roles in regulating osteoblasts and bone metabolism. However, the effects of miRNAs in osteoblast mechanotransduction remain to be defined. In this study, we investigated the regulatory effect of miR-33-5p in osteoblasts and tested its anti-osteopenia effect when delivered by an osteoblast-targeting delivery system in vivo. First, we demonstrated that miR-33-5p could promote the activity and mineralization of osteoblasts without influencing their proliferation in vitro. Then our data showed that supplementing miR-33-5p in osteoblasts by a targeted delivery system partially recovered the osteopenia induced by mechanical unloading at the biochemical, microstructural, and biomechanical levels. In summary, our findings demonstrate that miR-33-5p is a key factor in the occurrence and development of the osteopenia induced by mechanical unloading. In addition, targeted delivery of the mimics of miR-33-5p is a promising new strategy for the treatment of pathological osteopenia.

Serum Osteocalcin and Testosterone Concentrations in Adult Males with or without Primary Osteoporosis: A Meta-Analysis

Osteocalcin (Ocn) and testosterone play important roles in male skeleton. However, the concentrations of serum osteocalcin and testosterone have never been systematically compared between populations with and without primary male osteoporosis, a common skeletal disorder in adult males. We searched the PubMed, Embase, and Cochrane Library for relevant studies. A meta-analysis was performed to compare the serum osteocalcin and testosterone concentrations between primary osteoporotic males and age-matched nonosteoporotic (non-OP) males. Five case-control studies with 300 adult males were included. We found no significant difference between cases and controls in serum total osteocalcin (TOcn) [95% confidence interval (CI): −1.25, 1.31; p = 0.96] and total testosterone (TT) concentrations [95% CI: −0.88, 4.22; p = 0.20]. The level of evidence of this carefully performed meta-analysis is 3a according to Oxford (UK) CEBM Levels of Evidence. Future well-designed studies with larger sample size and better standardization of Ocn assay are awaited to confirm and update our current findings.

Effects of water-based exercise on bone health of middle-aged and older adults: a systematic review and meta-analysis

BACKGROUND

Age-related bone loss is a major health concern. Only exercises associated with high-impact and mechanical loading have been linked to a positive effect on bone turnover; however, these types of exercises may not always be appropriate for middle-aged and older adults due to physical decline or chronic disorders such as osteoarthritis. Water-based exercise (WBE) has been shown to affect different components of physical fitness, has lower risks of traumatic fracture, and applies less stress to joints. However, the effects of WBE on bone health are unclear.

OBJECTIVE

This study aimed to explore whether WBE is effective in preventing age-related bone deterioration in middle-aged and older adults.

METHODS

A search of relevant databases and the references of identified studies was performed. Critical narrative synthesis and meta-analyses were conducted.

RESULTS

Eleven studies, involving 629 participants, met all inclusion criteria. All participants were postmenopausal women. Eight studies compared WBE to a sedentary control group, and four studies had land-based exercise (LBE) participants as a comparison group. Meta-analyses revealed significant differences between WBE and control group in favor of WBE for changes in bone mineral density (BMD) at the lumbar spine (mean difference [MD] 0.03 g/cm²; 95% confidence interval [CI]: 0.01 to 0.05) and femoral neck (MD 0.04 g/cm²; 95% CI: 0.02 to 0.07). Significant differences were also revealed between WBE and LBE in favor of LBE for changes in lumbar spine BMD (MD -0.04 g/cm²; 95% CI: -0.06 to -0.02). However, there was no significant difference between WBE and LBE for changes in femoral neck BMD (MD -0.03 g/cm²; 95% CI: -0.08 to 0.01).

CONCLUSION

WBE may have benefits with respect to maintaining or improving bone health in postmenopausal women but less benefit when compared to LBE. Further research is required on this topic.

Medication use and risk of falls among nursing home residents: a retrospective cohort study

Background Geriatric falls are leading causes of hospital trauma admissions and injury-related deaths. Medication use is a crucial element among extrinsic risk factors for falls. To reduce fall risk and the prevalence of adverse drug reactions, potentially inappropriate medication (PIM) lists are widely used. Objective Our aim was to investigate the possible predictors of geriatric falls annualized over a 5-year-long period, as well as to evaluate the medication use of nursing home residents. Setting Nursing home residents were recruited from the same institution between 2010 and 2015 in Szeged, Hungary. Method A retrospective epidemiological study was performed. Patient data were analysed for the first 12 months of residency. Chi-squared test and Fisher's-test were applied to compare the categorical variables, Student's t test to compare the continuous variables between groups. Binary logistic regression analysis was carried out to determine the association of falls with other variables found significant in univariate analysis. Microsoft Excel, IBM SPSS Statistics (version 23) and R (3.2.2) programs were used for data analysis. Main outcome measure Falls affected by age, gender, number of chronic medications, polypharmacy, PIM meds. Results A total of 197 nursing home residents were included, 150 (76.2%) women and 47 (23.8%) men, 55 fallers (annual fall prevalence rate was 27.9%) and 142 non-fallers. Gender was not a predisposing factor for falls (prevalence in males: 23.4 vs 29.3% in females, p > 0.05). Fallers were older (mean years ± SD; 84.0 ± 7.0) than non-fallers (80.1 ± 9.3, p < 0.01). The age ≥80 years was a significant risk factor for falls (p < 0.001). The number of chronic medications was higher in male fallers (12.4 ± 4.0) than in non-fallers (6.9 ± 4.2, p < 0.001). Polypharmacy (taking four or more chronic medications) was a significant risk factor of falls (p < 0.01). Those PIMs carrying fall risk were taken by 70.9% of fallers and 75.3% of non-fallers (p > 0.05). Taking pantoprazole, vinpocetine or trimetazidine was a significant risk factor for falls. Conclusion Older age, polypharmacy and the independent use of pantoprazole, vinpocetine, and trimetazidine were found to be major risk factors for falls. Further real-life epidemiological studies are necessary to confirm the role of particular active agents, and to help professionals prescribe, evaluate and review geriatric medication use.

New horizons in treatment of osteoporosis

BACKGROUND

Prevalence of osteoporosis is increasing both in developed and developing countries. Due to rapid growth in the burden and cost of osteoporosis, worldwide, it seems reasonable to focus on the reduction of fractures as the main goal of treatment. Although, efficient pharmacological agents are available for the treatment of osteoporosis, there still remains a need to more specific drugs with less adverse effects.

MAIN BODY

This review article provides a brief update on the pathogenesis, presenting current pharmacological products approved by the US Food and Drug Administration (FDA) or Europe, and also newer therapeutic agents to treat osteoporosis according to the clinical trial data available at PubMed, UpToDate, International Osteoporosis Foundation (IOF), and clinical practice guidelines. As well, the effect of combination therapy and recommendations for future research will be further discussed.

SHORT CONCLUSION

The use of current antiresorptive and anabolic agents alone or in combinations for the treatment of osteoporosis entails several limitations. Mainly, their efficacy on non-vertebral fracture reduction is lower than that observed on vertebral fracture. In addition, they have potential adverse events on long time usage. Development of newer agents such as cathepsin k inhibitor and strontium ranelate not only have increased the available options for treating osteoporosis, but also have opened doors of opportunity to improvements in the effective treatment. However, the high cost of new agents have restricted their usage in selective patients who are at high risk of fracture or whom failed response to first line treatment options. Thus, personalized medicine should be considered for future evaluation of genetic risk score and also for environmental exposure assessment. In addition to permanent attention to early diagnosis of osteoporosis and understanding of the pathophysiology of osteoporosis for novel approach in drug discovery, there seems a need to more well-designed clinical trials with larger sample sizes and longer duration on current as well as on newer agents. Also, continuous research on plant-derived components as the source of discovering new agents, and conducting more clinical trials with combination of two or more synthetic drugs, plants, or drug-plant for the treatment of osteoporosis are recommended. Summary of treatment modalities for osteoporosis.

The Association between Bone Quality and Atherosclerosis: Results from Two Large Population-Based Studies

OBJECTIVE

It is highly debated whether associations between osteoporosis and atherosclerosis are independent of cardiovascular risk factors. We aimed to explore the associations between quantitative ultrasound (QUS) parameters at the heel with the carotid artery intima-media thickness (IMT), the presence of carotid artery plaques, and the ankle-brachial index (ABI).

METHODS

The study population comprised 5680 men and women aged 20-93 years from two population-based cohort studies: Study of Health in Pomerania (SHIP) and SHIP-Trend. QUS measurements were performed at the heel. The extracranial carotid arteries were examined with B-mode ultrasonography. ABI was measured in a subgroup of 3853 participants. Analyses of variance and linear and logistic regression models were calculated and adjusted for major cardiovascular risk factors.

RESULTS

Men but not women had significantly increased odds for carotid artery plaques with decreasing QUS parameters independent of diabetes mellitus, dyslipidemia, and hypertension. Beyond this, the QUS parameters were not significantly associated with IMT or ABI in fully adjusted models.

CONCLUSIONS

Our data argue against an independent role of bone metabolism in atherosclerotic changes in women. Yet, in men, associations with advanced atherosclerosis, exist. Thus, men presenting with clinical signs of osteoporosis may be at increased risk for atherosclerotic disease.

Estrogens and Androgens in Skeletal Physiology and Pathophysiology

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

Osteoporosis and Prevalent Fractures among Adult Filipino Men Screened for Bone Mineral Density in a Tertiary Hospital

BACKGROUND

Osteoporosis in men is markedly underdiagnosed and undertreated despite higher morbidity and mortality associated with fractures. This study aimed to characterize adult Filipino men with osteopenia, osteoporosis and prevalent fractures.

METHODS

A cross-sectional study of 184 Filipino men ≥50 years screened for bone mineral density was performed. Age, weight, body mass index (BMI), Osteoporosis Self-Assessment Tool for Asians (OSTA) score, smoking status, family history of fracture, diabetes mellitus, physical inactivity, and T-score were considered.

RESULTS

Of the 184 patients, 40.2% and 29.9% have osteopenia and osteoporosis. Sixteen (21.6%) and 18 (32.1%) osteopenic and osteoporotic men have fragility hip, spine, or forearm fractures. Men aged 50 to 69 years have the same risk of osteoporosis and fractures as those ≥70 years. While hip fractures are higher in osteoporotic men, vertebral fractures are increased in both osteopenic and osteoporotic men. Mere osteopenia predicts the presence of prevalent fractures. A high risk OSTA score can predict fracture. A BMI <21 kg/m² (P<0.05) and current smoking are associated with osteoporosis.

CONCLUSION

A significant fraction of Filipino men with osteopenia and osteoporosis have prevalent fractures. Our data suggest that fractures occur in men <70 years even before osteoporosis sets in. Low BMI, high OSTA score, and smoking are significant risk factors of osteoporosis.

The Peripheral Blood Mononuclear Cell Count Is Associated With Bone Health in Elderly Men: A Cross-Sectional Population-Based Study

The peripheral blood mononuclear cell (PBMC) count is a routinely used and meaningful index for infection and blood diseases. PBMCs may be closely related to osteoclasts and include osteoclast precursors; we examined the association between the PBMC count and bone health. This research included 2806 community men aged ≥50 years who underwent full health examinations from October 2007 through December 2011 in four medical centers. The PBMC count was significantly high among subjects with "at least osteopenia" compared with controls. In analysis of covariance adjusted for potential confounders, the bone mineral density (BMD) value and T-score had a significant decreasing trend across the quartiles of PBMC count. In univariate analysis, the PBMC count had a strong association with "at least osteopenia" (odds ratio [OR] = 2.520, 95% confidence interval [CI]: 1.397-4.547). After adjustment for confounding factors (multivariate analysis) from Model 1 to 4, PBMC count remained as an independent risk factor for "at least osteopenia" (OR = 2.481, 95% CI: 1.176-5.236). Moreover, after adjusting for all confounding variables, participants had a significantly high OR in the body mass index (BMI) <25 group (OR = 2.798, CI: 1.122-6.973; P = 0.027) and systolic blood pressure (SBP) <140 group (OR = 2.519, CI: 1.059-5.993; P = 0.037). In conclusion, the PBMC count is significantly associated with bone loss in elderly men and the exact mechanism requires further clarification.

Tadalafil modulates aromatase activity and androgen receptor expression in a human osteoblastic cell in vitro model

PURPOSE

Phosphodiesterase type-5 inhibitor (PDE5i) tadalafil administration in men with erectile dysfunction is associated with increased testosterone/estradiol ratio, leading to hypothesize a potential increased effect of androgen action on target tissues. We aimed to characterize, in a cellular model system in vitro, the potential modulation of aromatase and sex steroid hormone receptors upon exposure to tadalafil (TAD).

METHODS

Human osteoblast-like cells SAOS-2 were chosen as an in vitro model system since osteoblasts are target of steroid hormones. Cells were tested for viability upon TAD exposure, which increased cell proliferation. Then, cells were treated with/without TAD for several times to evaluate potential modulation in PDE5, aromatase (ARO), androgen (AR) and estrogen (ER) receptor expression.

RESULTS

Osteoblasts express significant levels of both PDE5 mRNA and protein. Exposure of cells to increasing concentrations of TAD (10(-8)-10(-7) M) decreased PDE5 mRNA and protein expression. Also, TAD inhibited ARO mRNA and protein expression leading to an increase in testosterone levels in the supernatants. Interestingly, TAD increased total AR mRNA and protein expression and decreased ERα, with an increased ratio of AR/ER, suggesting preferential androgenic vs estrogenic pathway activation.

CONCLUSIONS

Our results demonstrate for the first time that TAD decreases ARO expression and increases AR protein expression in human SAOS-2, strongly suggesting a new control of steroid hormones pathway by PDE5i. These findings might represent the first evidence of translational actions of PDE5i on AR, which leads to hypothesize a growing relevance of this molecule in men with prostate cancer long-term treated with TAD for sexual rehabilitation.

An update on the role of testosterone replacement therapy in the management of hypogonadism

While US testosterone prescriptions have tripled in the last decade with lower trends in Europe, debate continues over the risks, benefits and appropriate use of testosterone replacement therapy (TRT). Some authors blame advertising and the availability of more convenient formulations whilst other have pointed out that the routine testing of men with erectile dysfunction (a significant marker of cardiovascular risk) and those with diabetes would inevitably increase the diagnosis of hypogonadism and lead to an increase in totally appropriate prescribing. They commented that this was merely an appropriate correction of previous underdiagnosis and undertreatment by adherence to evidence-based guidelines. Urologists and primary care physicians are the most frequent initiators of TRT, usually for erectile dysfunction. Benefits are clearly established for sexual function, increase in lean muscle mass and strength, mood and cognitive function, with possible reduction in frailty and osteoporosis. There remains no evidence that TRT is associated with increased risk of prostate cancer or symptomatic benign prostatic hyperplasia, yet the decision to initiate and continue therapy is often decided by urologists. The cardiovascular issues associated with TRT have been clarified by recent studies showing clearly that therapy associated with clear rise in testosterone levels are associated with reduced mortality. Studies reporting to show increased risk have been subject to flawed designs with inadequate baseline diagnosis and follow-up testing. Effectively they have compared nontreated patients with undertreated or on-compliant subjects involving a range of different therapy regimens. Recent evidence suggests long acting injections may be associated with decreased cardiovascular risk but the transdermal route may be associated with potentially relatively greater risk because of conversion to dihydrotestosterone by the effect of 5α reductase in skin. The multiple effects of TRT may add up to a considerable benefit to the patient that might be underestimated by the physician primarily concerned with his own specialty. This paper will attempt to identify who should be treated, and how they should be treated safely to achieve best outcomes, based on a comprehensive MEDLINE and EMBASE and Cochrane searches on hypogonadism, TRT and cardiovascular safety from May 2005 to May 2015. This revealed 1714 papers with 52 clinical trials and 32 placebo-controlled randomized, controlled trials.

Are Changes in Composition in Response to Treatment of a Mouse Model of Osteogenesis Imperfecta Sex-dependent?

BACKGROUND

Osteogenesis imperfecta (OI) is a genetic disease characterized by skeletal fragility and deformity. There is extensive debate regarding treatment options in adults with OI. Antiresorptive treatment reduces the number of fractures in growing oim/oim mice, an animal model that reproducibly mimics the moderate-to-severe form of OI in humans. Effects of long-term treatments with antiresorptive agents, considered for treatment of older patients with OI with similar presentation (moderate-to-severe OI) are, to date, unknown.

QUESTIONS/PURPOSES

Fourier transform infrared (FTIR) imaging, which produces a map of the spatial variation in chemical composition in thin sections of bone, was used to address the following questions: (1) do oim/oim mice show a sex dependence in compositional properties at 6.5 months of age; (2) is there a sex-dependent response to treatment with antiresorptive agents used in the treatment of OI in humans; and (3) are any compositional parameters in oim/oim mice corrected to wild-type (WT) values after treatment?

METHODS

FTIR imaging data were collected from femurs from four to five mice per sex per genotype per treatment. Treatments were 24 weeks of saline, alendronate, or RANK-Fc; and 12 weeks of saline+12 weeks RANK-Fc and 12 weeks of alendronate+RANK-Fc. FTIR imaging compositional parameters measured in cortical and cancellous bones were mineral-to-matrix ratio, carbonate-to-mineral ratio, crystal size/perfection, acid phosphate substitution, collagen maturity, and their respective distributions (heterogeneities). Because of the small sample size, nonparametric statistics (Mann-Whitney U- and Kruskal-Wallis tests with Bonferroni correction) were used to compare saline-treated male and female mice of different genotypes and treatment effects by sex and genotype, respectively. Statistical significance was defined as p<0.05.

RESULTS

At 6.5 months, saline-treated male cortical oim/oim bone had increased mineral-to-matrix ratio (p=0.016), increased acid phosphate substitution (p=0.032), and decreased carbonate-to-mineral ratio (p=0.016) relative to WT. Cancellous bone in male oim/oim also had increased mineral-to-matrix ratio (p=0.016) relative to male WT. Female oim/oim mouse bone composition for all cortical and cancellous bone parameters was comparable to WT (p>0.05). Only the female WT mice showed a response of mean compositional properties to treatment, increasing mineral-to-matrix after RANK-Fc treatment in cancellous bone (p=0.036) compared with saline-treated mice. Male oim/oim increased mineral-to-matrix cortical and cancellous bone heterogeneity in response to all long-term treatments except for saline+RANK-Fc (p<0.04); female oim/oim cortical mineral-to-matrix bone heterogeneity increased with ALN+RANK-Fc and all treatments increased cancellous female oim/oim bone acid phosphate substitution heterogeneity (p<0.04).

CONCLUSIONS

Both oim/oim and WT mice, which demonstrate sex-dependent differences in composition with saline treatment, showed few responses to long-term treatment with antiresorptive agents. Female WT mice appeared to be more responsive; male oim/oim mice showed more changes in compositional heterogeneity. Changes in bone composition caused by these agents may contribute to improved bone quality in oim/oim mice, because the treatments are known to reduce fracture incidence.

CLINICAL RELEVANCE

The optimal drug therapy for long-term treatment of patients with moderate-to-severe OI is unknown. Based on bone compositional changes in mice, antiresorptive treatments are useful for continued treatment in OI. There is a reported sexual dimorphism in fracture incidence in adults with OI, but to date, no one has reported differences in response to pharmaceutical intervention. This study suggests that such an investigation is warranted.

Targeting metabolic disorders by natural products

The most prevalent metabolic disorders are diabetes mellitus, obesity, dyslipidemia, osteoporosis and metabolic syndrome, which are developed when normal metabolic processes are disturbed. The most common pathophysiologies of the above disorders are oxidative stress, Nrf2 pathways, epigenetic, and change in miRNA expression. There is a challenge in the prevention and treatment of metabolic disorders due to severe adverse effects of some synthetic drugs, their high cost, lack of safety and poverty in some conditions, and insufficient accessibility for the general population in the world. With increasing interest in shifting from synthetic drugs to phytotherapy as an alternative treatment, there is still a gap in scientific evidences of plant-derived therapeutic benefits. One reason may be slow rate of translation of animal studies' findings into human clinical trials. Since metabolic disorders are multifactorial, it seems that poly-herbal medications, or drug-herbal combination are needed for their treatment. However, further researches to determine the most effective plant-derived metabolites, and their cellular mechanism in order to set priorities for well-designed animal and clinical trials, and also more studies with strong scientific evidences such as systematic review and meta-analysis of controlled studies are needed.

Injection of testosterone may be safer and more effective than transdermal administration for combating loss of muscle and bone in older men

The value of testosterone replacement therapy (TRT) for older men is currently a topic of intense debate. While US testosterone prescriptions have tripled in the past decade (9), debate continues over the risks and benefits of TRT. TRT is currently prescribed for older men with either low serum testosterone (T) or low T plus accompanying symptoms of hypogonadism. The normal range for serum testosterone is 300 to 1,000 ng/dl. Serum T ≤ 300 ng/dl is considered to be low, and T ≤ 250 is considered to be frank hypogonadism. Most experts support TRT for older men with frank hypogonadism and symptoms. Treatment for men who simply have low T remains somewhat controversial. TRT is most frequently administered by intramuscular (im) injection of long-acting T esters or transdermally via patch or gel preparations and infrequently via oral administration. TRT produces a number of established benefits in hypogonadal men, including increased muscle mass and strength, decreased fat mass, increased bone mineral density, and improved sexual function, and in some cases those benefits are dose dependent. For example, doses of TRT administered by im injection are typically higher than those administered transdermally, which results in greater musculoskeletal benefits. TRT also produces known risks including development of polycythemia (Hct > 50) in 6% of those treated, decrease in HDL, breast tenderness and enlargement, prostate enlargement, increases in serum PSA, and prostate-related events and may cause suppression of the hypothalamic-pituitary-gonadal axis. Importantly, TRT does not increase the risk of prostate cancer. Putative risks include edema and worsening of sleep apnea. Several recent reports have also indicated that TRT may produce cardiovascular (CV) risks, while others report no risk or even benefit. To address the potential CV risks of TRT, we have recently reported via meta-analysis that oral TRT increases CV risk and suggested that the CV risk profile for im TRT may be better than that for oral or transdermal TRT.

Sex steroid actions in male bone

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

Androgens and estrogens in skeletal sexual dimorphism

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

Gender inequalities in the treatment of osteoporosis

INTRODUCTION

Our aim was to perform both gender- and age-specific analysis regarding the utilisation of anti-osteoporotic drugs in Hungary, between 2007 and 2011, and to compare our results with other European countries.

METHODS

The database of the Hungarian National Health Insurance Fund was screened for anti-osteoporotic medications, covering 100% of the Hungarian population (10 million people). ICD coding system (International Classification of Diseases) and WHO ATC/DDD methodology were used for medication screening and analysis.

RESULTS

In Hungary, the total bisphosphonate use was 6.66 DDD/TID (Defined Daily Dose/1000 inhabitants/day) in 2007, and 6.22 DDD/TID in 2011; the rate of bisphosphonate combinations slightly increased from 1.60 to 2.81 DDD/TID. The total vitamin D use almost doubled (13.73 DDD/TID in 2011), while the calcium supplementation tripled (4.47 DDD/TID in 2011), and so did the strontium ranelate utilisation (0.70 DDD/TID in 2011) within the investigated time period. Denosumab consumption was marginal. Male patients were disproportionately, 10-20 times undertreated in all age groups, and treatment choice was restricted among men. Several differences were seen in our results compared to those in Baltic countries, Finland and in Norway.

CONCLUSIONS

Men were significantly undertreated in all age groups, compared to women. The 10 to 20-fold difference calls attention to this unrecognised problem.

Progressive Improvement of T-Scores in Men with Osteoporosis and Subnormal Serum Testosterone Levels upon Treatment with Testosterone over Six Years

Testosterone deficiency leads to bone loss and testosterone treatment has a beneficial effect. This study investigated the effects of normalizing serum testosterone on bone mineral density in 45 men with osteoporosis, diagnosed with testosterone deficiency (serum testosterone levels <12.1 nmol/L, T-scores: (mean ± SD) -3.12 ± 0.45, minimum: -4.10, and maximum: -2.60). In a cumulative, prospective, registry study of hypogonadal men (mean age: 53 ± 7 years) they received parenteral testosterone undecanoate of 1000 mg/12 weeks for up to six years. After one year 44 men were included in the registry, after two years 36 men, after three years 32 men, after four years 25 men, after five years 10 men and after six years 4 men. The declining numbers do not reflect drop-out rates but are a result of the registry design. Over the 6 year period there was a significant and progressive improvement of the T-scores in these men. Normalizing of serum testosterone leads to an improvement of bone mineral density and this improvement was progressive with the time period of testosterone administration. In this study of 6-years many men with testosterone deficiency suffered from classical diagnoses (Klinefelter's syndrome and testicular pathology) hitherto undiagnosed.