Testosterone therapy and cardiovascular events among men: a systematic review and meta-analysis of placebo-controlled randomized trials

Role of sex hormones in modulating myocardial perfusion and coronary flow reserve

Background

A growing body of evidence highlights sex differences in the diagnostic accuracy of cardiovascular imaging modalities. Nonetheless, the role of sex hormones in modulating myocardial perfusion and coronary flow reserve (CFR) is currently unclear. The aim of our study was to assess the impact of female and male sex hormones on myocardial perfusion and CFR.

Methods

Rest and stress myocardial perfusion imaging (MPI) was conducted by small animal positron emission tomography (PET) with [¹⁸F]flurpiridaz in a total of 56 mice (7–8 months old) including gonadectomized (Gx) and sham-operated males and females, respectively. Myocardial [¹⁸F]flurpiridaz uptake (% injected dose per mL, % ID/mL) was used as a surrogate for myocardial perfusion at rest and following intravenous regadenoson injection, as previously reported. Apparent coronary flow reserve (CFR_App) was calculated as the ratio of stress and rest myocardial perfusion. Left ventricular (LV) morphology and function were assessed by cardiac magnetic resonance (CMR) imaging.

Results

Orchiectomy resulted in a significant decrease of resting myocardial perfusion (Gx vs. sham, 19.4 ± 1.0 vs. 22.2 ± 0.7 % ID/mL, p = 0.034), while myocardial perfusion at stress remained unchanged (Gx vs. sham, 27.5 ± 1.2 vs. 27.3 ± 1.2 % ID/mL, p = 0.896). Accordingly, CFR_App was substantially higher in orchiectomized males (Gx vs. sham, 1.43 ± 0.04 vs. 1.23 ± 0.05, p = 0.004), and low serum testosterone levels were linked to a blunted resting myocardial perfusion (r = 0.438, p = 0.020) as well as an enhanced CFR_App (r = −0.500, p = 0.007). In contrast, oophorectomy did not affect myocardial perfusion in females. Of note, orchiectomized males showed a reduced LV mass, stroke volume, and left ventricular ejection fraction (LVEF) on CMR, while no such effects were observed in oophorectomized females.

Conclusion

Our experimental data in mice indicate that sex differences in myocardial perfusion are primarily driven by testosterone. Given the diagnostic importance of PET-MPI in clinical routine, further studies are warranted to determine whether testosterone levels affect the interpretation of myocardial perfusion findings in patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00259-022-05675-2.

Trends in testosterone prescription amongst medical specialties: a 5-year CMS data analysis

Testosterone Therapy (TTh) trends have changed as a result of clinical research and market forces over the past several years. Understanding the trends or preferences regarding testosterone prescriptions remains unknown. Our objective was to assess both regional and national trends in TTh prescriptions amongst medical specialties within the United States between 2013 and 2017. Publicly available data from the Center for Medicare and Medicaid Services (CMS) Part D Prescriber database with regards to TTh prescriptions across a 5-year span (January 1, 2013-December 31, 2017) were analyzed. TTh therapies were consolidated into four categories: Topical, Oral, Injection and Pellet. Statistical analysis utilizing R 4.0.2 was performed on the resulting data. Trends in prescription modality claim count and cost were plotted over the study period while statistical analysis evaluated associations between TTh modality and medical specialist. We found that Endocrinologists and Urologists prescribed topical testosterone more than all other specialties (60.4% and 53.5%, respectively), while Family and Internal medicine physicians were more likely to prescribe injections (59.82% and 50.69%, respectively). Oral and pellet testosterone were rarely prescribed across all specialties. In conclusion, the wide variation in modalities of testosterone prescriptions illustrates an opportunity for treatment guidelines to be streamlined across all specialists to improve patient outcomes.

Obesity, Body Composition, and Sex Hormones: Implications for Cardiovascular Risk

Cardiovascular disease (CVD) continues to be the leading cause of death in adults, highlighting the need to develop novel strategies to mitigate cardiovascular risk. The advancing obesity epidemic is now threatening the gains in CVD risk reduction brought about by contemporary pharmaceutical and surgical interventions. There are sex differences in the development and outcomes of CVD; premenopausal women have significantly lower CVD risk than men of the same age, but women lose this advantage as they transition to menopause, an observation suggesting potential role of sex hormones in determining CVD risk. Clear differences in obesity and regional fat distribution among men and women also exist. While men have relatively high fat in the abdominal area, women tend to distribute a larger proportion of their fat in the lower body. Considering that regional body fat distribution is an important CVD risk factor, differences in how men and women store their body fat may partly contribute to sex-based alterations in CVD risk as well. This article presents findings related to the role of obesity and sex hormones in determining CVD risk. Evidence for the role of sex hormones in determining body composition in men and women is also presented. Lastly, the clinical potential for using sex hormones to alter body composition and reduce CVD risk is outlined. © 2022 American Physiological Society. Compr Physiol 12:1-45, 2022.

Genetically predicted sex hormone binding globulin and ischemic heart disease in men and women: a univariable and multivariable Mendelian randomization study

Men are more vulnerable to ischemic heart disease (IHD) than women, possibly due to testosterone. Correspondingly, sex hormone binding globulin (SHBG) which lowers circulating testosterone might protect men against IHD. SHBG may also affect IHD independent of testosterone, which has not previously been examined. To assess the sex-specific role of SHBG in IHD, in univariable Mendelian randomization (MR), we used sex-specific, genome-wide significant genetic variants to predict SHBG, and examined their association with IHD in the UK Biobank. We also replicated using genetic instruments from Japanese men and applied to Biobank Japan. To assess the role of SHGB independent of testosterone in men, we used multivariable MR controlling for testosterone. Genetically predicted SHBG was associated with lower IHD risk in men [odds ratio (OR) 0.78 per standard deviation, 95% confidence interval (CI) 0.70 to 0.87], and the association was less clear in women. The estimates were similar in Japanese. The inverse association remained after controlling for testosterone in men (OR 0.79, 95% CI 0.71 to 0.88). SHBG might lower the risk of IHD in men, with a role independent of testosterone. Exploring intervention strategies that increase SHBG is important for targeting IHD treatments.

Serum testosterone levels and testosterone supplementation in cirrhosis: A systematic review

BACKGROUND & AIMS

Cirrhosis disrupts the hypothalamic-pituitary-gonadal axis causing low testosterone. Testosterone deficiency is associated with sarcopenia and osteopenia, leading to a state of frailty and worse clinical outcomes, morbidity and mortality. We aimed to conduct a systematic review on the relationship between serum testosterone and laboratory, anthropometric and clinical outcomes in observational and interventional studies in cirrhosis.

METHODS

PubMed and EMBASE were searched from inception through 27 August 2020 and reviewed independently by two investigators; a third reviewer solved disagreement. A qualitative summary of relevant findings was done. Methodological quality was assessed using the Newcastle Ottawa Scale for non-interventional studies and the Cochrane Risk of Bias for interventional studies.

RESULTS

Out of 3569 articles, 15 met inclusion criteria with six observational studies of 1267 patients and nine interventional studies of 580 patients. In observational studies, low serum testosterone level was associated with sarcopenia, shorter median time to hepatic decompensation, transplant requirement, higher model for end-stage liver disease (MELD) scores, and death in cirrhotic patients. Nine interventional studies (361 treated with testosterone vs 219 placebo, 1-36 months) showed that testosterone supplementation improved serum testosterone, appendicular mass and bone mineral density. However, no trial reported improvement in liver-related scores, complications, readmission rates or death.

CONCLUSIONS

Low serum testosterone is associated with increased morbidity and mortality in cirrhosis patients. Testosterone supplementation improved intermediate endpoints, but there was no conclusive data on clinical outcomes. Testosterone supplementation may be a promising strategy to improve frailty and decrease significant clinical complications in cirrhosis.

Association Between Testosterone Treatment and Risk of Incident Cardiovascular Events Among US Male Veterans With Low Testosterone Levels and Multiple Medical Comorbidities

Background

Testosterone treatment is common in men, although risks for major cardiovascular events are unclear.

Methods and Results

A study was conducted in US male veterans, aged ≥40 years, with low serum testosterone and multiple medical comorbidities and without history of myocardial infarction, stroke, venous thromboembolism, prostate cancer, or testosterone treatment in the prior year. For the primary outcome, we examined if testosterone treatment was associated with a composite cardiovascular outcome (incident myocardial infarction, ischemic stroke, or venous thromboembolism). Testosterone use was modeled as intramuscular or transdermal and as current use, former use, and no use. Current testosterone users were compared with former users to reduce confounding by indication. The cohort consisted of 204 857 men with a mean (SD) age of 60.9 (9.9) years and 4.7 (3.5) chronic medical conditions. During follow‐up of 4.3 (2.8) years, 12 645 composite cardiovascular events occurred. In adjusted Cox regression analyses, current use of transdermal testosterone was not associated with risk for the composite cardiovascular outcome (hazard ratio [HR], 0.89; 95% CI, 0.76–1.05) in those without prevalent cardiovascular disease, and in those with prevalent cardiovascular disease was associated with lower risk (HR, 0.80; 95% CI, 0.70–0.91). In similar analyses, current use of intramuscular testosterone was not associated with risk for the composite cardiovascular outcome in men without or with prevalent cardiovascular disease (HR, 0.91; 95% CI, 0.80–1.04; HR, 0.98; 95% CI, 0.89–1.09, respectively).

Conclusions

In a large cohort of men without a history of myocardial infarction, stroke, or venous thromboembolism, testosterone treatment was not associated with increased risk for incident composite cardiovascular events.

Anabolic-Androgenic Steroid Use in Sports, Health, and Society

This consensus statement is an update of the 1987 American College of Sports Medicine (ACSM) position stand on the use of anabolic-androgenic steroids (AAS). Substantial data have been collected since the previous position stand, and AAS use patterns have changed significantly. The ACSM acknowledges that lawful and ethical therapeutic use of AAS is now an accepted mainstream treatment for several clinical disorders; however, there is increased recognition that AAS are commonly used illicitly to enhance performance and appearance in several segments of the population, including competitive athletes. The illicit use of AAS by competitive athletes is contrary to the rules and ethics of many sport governing bodies. Thus, the ACSM deplores the illicit use of AAS for athletic and recreational purposes. This consensus statement provides a brief history of AAS use, an update on the science of how we now understand AAS to be working metabolically/biochemically, potential side effects, the prevalence of use among athletes, and the use of AAS in clinical scenarios.

How Would You Manage This Male Patient With Hypogonadism? : Grand Rounds Discussion From Beth Israel Deaconess Medical Center

Male hypogonadism is defined as an abnormally low serum testosterone concentration or sperm count. As men age, often in the context of obesity and other comorbid conditions, serum testosterone levels may decrease. Normalizing serum testosterone levels in male adults with hypogonadism may improve symptoms related to androgen deficiency, but controversies exist regarding the long-term benefits and risks of hormone supplementation in this setting. In 2020, the American College of Physicians published a clinical guideline for the use of testosterone supplementation in adult men based on a systematic review of available evidence. Among their recommendations were that clinicians discuss whether to initiate testosterone treatment in men with age-related low testosterone with sexual dysfunction who want to improve sexual function and not initiate testosterone treatment in men with age-related low testosterone to improve energy, vitality, physical function, or cognition. Here, two clinicians with expertise in this area, one a generalist and the other an endocrinologist, debate the management of a patient with sexual symptoms and a low serum testosterone level. They discuss the diagnosis of male hypogonadism, the indications for testosterone therapy, its potential benefits and risks, how it should be monitored, and how long it should be continued.

Energy Metabolism Focused Analysis of Sexual Dimorphism in Biological Aging and Hypothesized Sex-specificity in Sirtuin Dependency

The process of biological aging or senescence refers to the gradual loss of homeostasis and subsequent loss of function - leading to higher chances of mortality. Many mechanisms and driving forces have been suggested to facilitate the evolution of a molecular circuit acting as a trade-off between survival and proliferation, resulting in senescence. A major observation on biological aging and longevity in humans and model organisms is the prevalence of significant sexual divergence in the onset, mechanisms and effects of aging associated processes. In the current account, we describe possible mechanisms by which aging, sex and reproduction are evolutionarily intertwined in order to maintain systemic energy homeostasis. We also interrogate existing literature on the sexual dimorphism of genetic, cellular, metabolic, endocrine and epigenetic processes driving cellular and systemic aging. Subsequently, based on available evidence, we propose a hypothetic model of sex-limited decoupling of female longevity from sirtuins, a major family of regulator proteins of the survival-proliferation trade-off. We also provide necessary considerations to be made in order to test the hypothesis and explore the physiological and therapeutic implications of this decoupling event in male and female longevity after reaching reproductive maturity. HYPOTHESIS STATEMENT: Sirtuins provide survival benefits in a sex-nonspecific manner but the dependency on sirtuins in driving metabolic networks after reaching reproductive maturity is evolutionarily decoupled from female longevity.

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.

A Novel Liver-targeted Testosterone Therapy for Sarcopenia in Androgen Deprived Men With Prostate Cancer

Objective

Androgen deprivation therapy (ADT) reduces muscle and bone mass, increasing frailty in men with prostate cancer. The liver mediates the whole body anabolic effects of testosterone. Based on first-pass metabolism, liver-targeted testosterone treatment (LTTT) entails oral delivery of a small dose of testosterone that does not raise peripheral blood testosterone levels. LTTT reduces blood urea and stimulates protein anabolism in hypogonadal men and postmenopausal women. We investigated whether LTTT prevents loss of lean and bone mass during ADT.

Method

A 6-month, double-blind, placebo-controlled study of testosterone 40 mg/day in 50 men. Primary outcome measures were lean mass and bone mineral content (BMC). Testosterone, urea and prostate-specific antigen (PSA) were monitored. Patients were withdrawn if PSA exceeded 4 ng/mL.

Results

42 patients completed the study. Mean (95% CI) testosterone rose during LTTT but not placebo treatment [∆ 2.2 (1.3-3.0) vs -0.7 (-1.5 to 0.2) nmol/L; P < 0.01]. Mean PSA level did not change significantly during either treatment. Blood urea fell [∆ -0.4 (-0.9 to -0.1) mmol/L] during LTTT but not placebo [∆ 0.05 (-0.8 to 0.9) mmol/L]. BMC [∆ 49 (5 to 93) g; P < 0.02] and lean mass [∆ 0.8 (-0.1 to 1.7) kg; P = 0.04) increased compared to placebo. Five patients on LTTT withdrew from increased PSA levels, all returning to baseline levels.

Conclusion

LTTT shows promise as a simple therapy for preventing sarcopenia and bone loss during ADT. LTTT may induce reversible PSA rise in some patients. Further studies are required to optimize LTTT dose in ADT. LTTT has potential application in other catabolic states in men and women.

The impact of rosuvastatin on hypothalamic-pituitary-testicular axis activity in metformin-treated and metformin-naïve men with low testosterone levels: a pilot study

Background

Intense statin therapy was found to impair testosterone production in men. Metformin administered to subjects with hypergonadotropic hypogonadism decreased gonadotropin production. The current study was aimed at investigating whether metformin treatment modulates the impact of high-dose rosuvastatin therapy on hypothalamic–pituitary–testicular axis activity in men.

Methods

The study included 43 very high cardiovascular risk men with late-onset hypogonadism, 20 of whom had been treated with metformin (1.7–3 g daily) for at least 6 months. In all subjects, unsuccessful initial statin treatment was replaced with rosuvastatin (20–40 mg daily). Plasma lipid levels, glucose homeostasis markers, as well as circulating levels of gonadotropins, testosterone, bioavailable testosterone, dehydroepiandrosterone-sulfate, prolactin, estradiol and creatinine were measured at the beginning of the study and 4 months later in 28 individuals in whom rosuvastatin reduced LDL cholesterol levels to below 70 mg/dL.

Results

There were no differences between treatment-induced changes in plasma lipids. In both study groups, rosuvastatin reduced total and bioavailable testosterone levels. However, only in metformin-naïve men, rosuvastatin increased LH and FSH levels and slightly impaired insulin sensitivity. The impact on gonadotropin concentrations correlated with treatment-induced decrease in testosterone levels. There were no significant differences between baseline and posttreatment values of dehydroepiandrosterone-sulfate, prolactin, estradiol and the glomerular filtration rate.

Conclusion

The obtained results suggest that metformin prevents the compensatory increase in gonadotrope function induced by intense statin therapy.

Cardiovascular risk and testosterone - from subclinical atherosclerosis to lipoprotein function to heart failure

The cardiovascular (CV) benefit and safety of treating low testosterone conditions is a matter of debate. Although testosterone deficiency has been linked to a rise in major adverse CV events, most of the studies on testosterone replacement therapy were not designed to assess CV risk and thus excluded men with advanced heart failure or recent history of myocardial infarction or stroke. Besides considering observational, interventional and prospective studies, this review article evaluates the impact of testosterone on atherosclerosis process, including lipoprotein functionality, progression of carotid intima media thickness, inflammation, coagulation and thromboembolism, quantification of plaque volume and vascular calcification. Until adequately powered studies evaluating testosterone effects in hypogonadal men at increased CV risk are available (TRAVERSE trial), clinicians should ponder the use of testosterone in men with atherosclerotic cardiovascular disease and discuss benefit and harms with the patients.

Late-onset hypogonadism: Clinical evidence, biological aspects and evolutionary considerations

The growing life expectancy in modern societies has raised scientific interest in identifying medical interventions to alleviate age-associated pathologies such as vascular calcification, cognitive decline, sarcopenia, osteoporosis and sexual dysfunction. Although no such single treatment has thus far been established in humans, some clinicians and patients have set their hopes on testosterone replacement therapy (TRT) as a potential "fountain of youth" for aging men. While TRT has proven effective in ameliorating distinct symptoms of late-onset hypogonadism (LOH), its safety remains to be demonstrated. Besides humans, multiple other species exhibit age-related reductions in circulating testosterone levels, raising the question whether such changes are an inherent, pathological feature of growing organismal age or rather reflect an adaptive response. In this manuscript, we apply key principles of evolutionary medicine to testosterone biology and LOH to provide a novel perspective on these two fields. Additionally, we discuss insightful data derived from the animal kingdom to illustrate the plasticity of individual testosterone trajectories across the lifespan, outline cost-benefit-considerations of TRT in LOH and highlight potential caveats of such therapies.

Diagnosis and Management of Testosterone Deficiency in men: A review of the European and American Urology Associations

Ambiguous data on both terminology, diagnostics, and treatment of testosterone deficiency in men prompted us to attempt a critical analysis of existing knowledge on this subject. Current guidelines of both American and European Association of Urology (AUA, EUA) define testosterone therapy as effective and safe. However, media reports and some scientific reports indicating negative effects of the abovementioned therapy arouse aversion to its use by doctors and potential patients for fear of developing prostate cancer or cardiovascular incidents. The peak of scepticism about testosterone therapy was observed after the publication in 2013 and 2014, respectively, two retrospective data analysis on this topic, which resulted in the discontinuation of therapy in many patients with long histories of benefits from testosterone therapy. In addition, in many men with indications for testosterone therapy, this treatment was not used for fear of patient safety. However, the latest data on these concerns do not confirm any negative effects. More than 100 recently published scientific studies have shown the beneficial effects of testosterone therapy on many aspects of health. The American Society of Clinical Endocrinologists (AACE) and the American College of Endocrinology (ACE) have jointly developed their own literature assessment, stating that there is no convincing evidence that testosterone therapy increases the risk of cardiovascular incidents. The same conclusions can be drawn from the current EAU and AUA guidelines.

Serum free testosterone level in coronary artery disease in candidates for coronary artery bypass graft surgery: A cross-sectional study

Background

Due to the controversy over the effect of serum testosterone levels on coronary artery diseases, this survey explores the serum levels of free testosterone, luteinizing hormone, and follicle-stimulating hormone in candidates for coronary artery bypass graft compared with an age-matched control group and evaluates the associated factors in these participants.

Objective

To determine the testosterone level in elective coronary artery bypass grafting participants.

Materials and Methods

In this cross-sectional study, all male patients aged > 40 yr as candidates for elective coronary artery bypass grafting, who were referred to the Afshar Hospital, Yazd, Iran, from March 2018 to March 2019, were included. In total, 100 men were enrolled (50 cases and 50 controls). Their serum levels of free and total testosterone, luteinizing hormone, and follicle-stimulating hormone were measured and the results were compared.

Results

The findings indicated a significant difference between the two groups in total and free testosterone (both p < 0.001); they were lower in the case group. There was also a significant difference in the total testosterone of the participants with diabetes mellitus compared with no-diabetic individuals (p = 0.007). Free testosterone of diabetic subjects taking insulin was lower compared with those taking no insulin (p = 0.04). There was also an association between the body mass index and free testosterone, left ventricular ejection fraction and total testosterone, and a significant and negative relation between the duration of hospital admissions and free testosterone (p < 0.05).

Conclusion

This study illustrates that participants with coronary artery disease bear a significantly low testosterone level in comparison with the healthy control group.

Cardiovascular health after menopause transition, pregnancy disorders, and other gynaecologic conditions: a consensus document from European cardiologists, gynaecologists, and endocrinologists

Women undergo important changes in sex hormones throughout their lifetime that can impact cardiovascular disease risk. Whereas the traditional cardiovascular risk factors dominate in older age, there are several female-specific risk factors and inflammatory risk variables that influence a woman's risk at younger and middle age. Hypertensive pregnancy disorders and gestational diabetes are associated with a higher risk in younger women. Menopause transition has an additional adverse effect to ageing that may demand specific attention to ensure optimal cardiovascular risk profile and quality of life. In this position paper, we provide an update of gynaecological and obstetric conditions that interact with cardiovascular risk in women. Practice points for clinical use are given according to the latest standards from various related disciplines (Figure 1).

Leydig cell aging: Molecular mechanisms and treatments

Late-onset hypogonadism, resulting from deficiency in serum testosterone (T), affects the health and quality of life of millions of aging men. T is synthesized by Leydig cells (LCs) in response to luteinizing hormone (LH). LH binds LC plasma membrane receptors, inducing the formation of a supramolecular complex of cytosolic and mitochondrial proteins, the Steroidogenic InteracTomE (SITE). SITE proteins are involved in targeting cholesterol to CYP11A1 in the mitochondria, the first enzyme of the steroidogenic cascade. Cholesterol translocation is the rate-determining step in T formation. With aging, LC defects occur that include changes in SITE, an increasingly oxidative intracellular environment, and reduced androgen formation and serum T levels. T replacement therapy (TRT) will restore T levels, but reported side effects make it desirable to develop additional strategies for increasing T. One approach is to target LC protein-protein interactions and thus increase T production by the hypofunctional Leydig cells themselves.

Testosterone replacement therapy and the risk of venous thromboembolism: A systematic review and meta-analysis of randomized controlled trials

INTRODUCTION

The cardiovascular safety of testosterone replacement therapy (TRT) is controversial. While several studies have investigated the association between TRT and the risk of arterial thrombosis, limited information is available regarding its risk of venous thromboembolism (VTE). We aimed to compare the risk of VTE in men randomized to TRT versus placebo or active-comparator in a systematic review.

METHODS

We searched Medline, EMBASE, CINAHL, CENTRAL, and clinical trial registries to identify randomized controlled trials (RCTs) comparing TRT to placebo in men aged ≥18 years. We assessed study quality using the Cochrane Risk of Bias assessment tool and the overall quality of evidence using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) criteria. Data were pooled across RCTs using random-effects models.

RESULTS

A total of 13 RCTs (n = 5050) were included in our meta-analysis. In all, 2636 men were randomized to testosterone, and 2414 men to placebo. Sample sizes ranged from 101 to 790 men, and TRT duration from 3 to 36 months. Five studies had a high risk of bias, largely driven by unclear randomization and outcome assessment. When data were pooled across RCTs, testosterone therapy was not associated with VTE compared with placebo (RR: 1.03, 95% CI: 0.49-2.14; I²: 0%; low-quality evidence). Similar estimates were obtained for deep vein thrombosis and pulmonary embolism outcomes.

CONCLUSIONS

Our systematic review suggests that TRT is not associated with an increased risk of VTE. However, estimates were accompanied by a wide 95% CIs, and a clinically important increased risk cannot be ruled out.

Effects of Exogenous Androgens on Platelet Activity and Their Thrombogenic Potential in Supraphysiological Administration: A Literature Review

Anabolic androgenic steroids (AAS), simply called “androgens”, represent the most widespread drugs used to enhance performance and appearance in a sporting environment. High-dosage and/or long-term AAS administration has been associated frequently with significant alterations in the cardiovascular system, some of these with severe endpoints. The induction of a prothrombotic state is probably the most life-threatening consequence, suggested by numerous case reports in AAS-abusing athletes, and by a considerable number of human and animal studies assessing the influence of exogenous androgens on hemostasis. Despite over fifty years of research, data regarding the thrombogenic potential of exogenous androgens are still scarce. The main reason is the limited possibility of conducting human prospective studies. However, human observational studies conducted in athletes or patients, in vitro human studies, and animal experiments have pointed out that androgens in supraphysiological doses induce enhanced platelet activity and thrombopoiesis, leading to increased platelet aggregation. If this tendency overlaps previously existing coagulation and/or fibrinolysis dysfunctions, it may lead to a thrombotic diathesis, which could explain the multitude of thromboembolic events reported in the AAS-abusing population. The influence of androgen excess on the platelet activity and fluid–coagulant balance remains a subject of debate, urging for supplementary studies in order to clarify the effects on hemostasis, and to provide new compelling evidence for their claimed thrombogenic potential.

Testosterone Therapy and Cardiovascular Risk: A Critical Analysis of Studies Reporting Increased Risk

BACKGROUND

Treatment of "adult-onset hypogonadism" (AOH) with exogenous testosterone therapy (TTh) to raise serum testosterone (T) levels may influence cardiovascular (CV) risk factors in patients with AOH, whereas low endogenous T levels are associated with an increased CV risk and mortality.

AIM

To critically evaluate studies reporting increased CV risk associated with TTh and to provide an overview of the risks and benefits of restoring T levels through exogenous TTh.

METHODS

A review of publications focusing on the association between TTh and increased CV risk was conducted, and the study methodologies and conclusions of each were critically evaluated. Further, recent clinical and epidemiological studies associating AOH or TTh with a change in CV risk, and pertinent hematologic and vascular effects noted in animal studies and in vitro, as well as in clinical practice were also reviewed.

OUTCOMES

A review of the literature shows that untreated testosterone deficiency and/or low T is associated with an increase in CV risk and adverse outcomes, with numerous studies and meta-analyses to support a positive association between exogenous TTh and an improvement in CV risk factors in men with AOH.

RESULTS

Numerous studies in the literature demonstrate the positive benefits of using TTh; however, since 2013, some publications have suggested a link to increased CV risk associated with TTh. A number of these studies retrospectively analyzed insurance claims databases using diagnosis codes, procedures codes, and prescription information. Many reviews published since have pointed out the methodological flaws and debatable conclusions of these studies.

CLINICAL IMPLICATIONS

A careful assessment of the patient's current health status and CV risk factors should be weighed against the benefits and possible risks resulting from TTh, and consideration should be given to deferring treatment pending resolution or stabilization of CV disease or risk factors.

STRENGTHS & LIMITATIONS

In this review, we provide an in-depth analysis of studies reporting increased CV risk with TTh. Many of the studies were not well-designed, randomized, double-blind, prospective clinical trials but rather post hoc analyses of cohort data. These studies may reflect bias in how treatment and nontreatment decisions are made or reflect conclusions based on widely cited methodological flaws.

CONCLUSION

Appropriate patient selection supported by low pre-treatment T levels and monitoring T levels during treatment with the goal of achieving and maintaining physiologic levels all contribute to the safe and effective use of TTh in men with AOH. Khera M, Miner M, Jaffe J, et al. Testosterone Therapy and Cardiovascular Risk: A Critical Analysis of Studies Reporting Increased Risk. J Sex med 2021;18:83-98.

Suppression of myofilament cross-bridge kinetic in the heart of orchidectomized rats

AIMS

The increased incidence of heart failure with reduced ejection fraction in men compared with women suggests that male sex hormones significantly impact myocardial contractile activation. This study aims to examine associations among molecular alterations, cellular modulations and in vivo cardiac contractile function upon deprivation of testicular hormones.

MAIN METHODS

Myocardial structure and functions were compared among sham-operated control and twelve-week orchidectomized (ORX) male rats with and without testosterone supplementation.

KEY FINDINGS

Echocardiography and pressure-volume relationships demonstrated a decreased left ventricular ejection fraction compared with sham-operated controls. The percentage of contractility reduction was generally similar to the decrease in tension development detected in both right ventricular trabeculae and skinned isolated left ventricular cardiomyocytes of ORX rats. Reductions in tension cost and the rate constant of tension redevelopment (k_tr) in ORX samples suggested a decrease in the rate of cross-bridge formation, reflecting a reduced number of cross-bridges. Slow cross-bridge detachment in ORX rat hearts could result from a shift of myosin heavy chain isoforms towards a slower ATPase activity β-isoform and reductions in the phosphorylation levels of cardiac troponin I and myosin binding protein-C. All the changes in the ORX rat heart, including ejection fractions and myofilament protein expression and phosphorylation, were completed attenuated by a physiological dose of testosterone.

SIGNIFICANCE

Testosterone plays a critical role in regulating the mechanical and contractile dynamics of the heart. Deprivation of male sex hormones cause the loss of normal preserved cardiac contractile function leading to a high risk of severe cardiomyopathy progression.

Reflections on the T Trials

BACKGROUND

This manuscript is a review and discussion of the published results of the T Trials.

OBJECTIVE

To re-examine the efficacy of testosterone replacement of hypogonadal men >65 years of age in the T Trials.

MATERIALS AND METHODS

The T Trials were a complex collection of seven double blind, placebo-controlled trials of the efficacy of testosterone as replacement therapy for older men with unequivocal hypogonadism. There were three main trials (sexual function; physical function; vitality) and four sub-trials (cognition; bone; anemia; and cardiovascular). All subjects participated in the main trials while more selective inclusion/exclusion criteria existed for the sub-trials. Subjects were excluded for perceived higher risk of prostate cancer and recent myocardial or cerebral vascular events.

RESULTS

The previously published results are reviewed here as seen in the context of this special issue on late-onset hypogonadism. In the T Trials, positive benefits were seen in the sexual function, bone, and anemia trials with small but significant benefits in the vitality trial. No benefit was seen in the cognition trial, partial benefit in physical function, and a negative benefit outcome seen in the cardiovascular trial. The later trial was underpowered and the results were described as exploratory. Adverse events were relatively uncommon in the 12-month treatment phase and additional 12-month post-treatment phase. The most frequent adverse effect ascribed to testosterone was erythrocytosis.

CONCLUSIONS

The T Trials studied the efficacy of testosterone replacement therapy on 788 men with low testosterone and symptoms of hypogonadism. The studies demonstrated benefits in four trials (sexual function, vitality, bone, and anemia); partial benefit in the physical function trial; no effect in the cognition trial; and a negative effect in the exploratory cardiovascular trial. The T Trials were not designed to assess long-term risks of testosterone in men.

Primary human testicular PDGFRα+ cells are multipotent and can be differentiated into cells with Leydig cell characteristics in vitro

STUDY QUESTION

Is it possible to differentiate primary human testicular platelet-derived growth factor receptor alpha positive (PDGFRα⁺) cells into functional Leydig cells?

SUMMARY ANSWER

Although human testicular PDGFRα⁺ cells are multipotent and are capable of differentiating into steroidogenic cells with Leydig cell characteristics, they are not able to produce testosterone after differentiation.

WHAT IS KNOWN ALREADY

In rodents, stem Leydig cells (SLCs) that have been identified and isolated using the marker PDGFRα can give rise to adult testosterone-producing Leydig cells after appropriate differentiation in vitro. Although PDGFRα⁺ cells have also been identified in human testicular tissue, so far there is no evidence that these cells are true human SLCs that can differentiate into functional Leydig cells in vitro or in vivo.

STUDY DESIGN, SIZE, DURATION

We isolated testicular cells enriched for interstitial cells from frozen–thawed fragments of testicular tissue from four human donors. Depending on the obtained cell number, PDGFRα⁺-sorted cells of three to four donors were exposed to differentiation conditions in vitro to stimulate development into adipocytes, osteocytes, chondrocytes or into Leydig cells. We compared their cell characteristics with cells directly after sorting and cells in propagation conditions. To investigate their differentiation potential in vivo, PDGFRα⁺-sorted cells were transplanted in the testis of 12 luteinizing hormone receptor-knockout (LuRKO) mice of which 6 mice received immunosuppression treatment. An additional six mice did not receive cell transplantation and were used as a control.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Human testicular interstitial cells were cultured to Passage 3 and FACS sorted for HLA-A,B,C⁺/CD34⁻/PDGFRα⁺. We examined their mesenchymal stromal cell (MSC) membrane protein expression by FACS analyses. Furthermore, we investigated lineage-specific staining and gene expression after MSC trilineage differentiation. For the differentiation into Leydig cells, PDGFRα⁺-sorted cells were cultured in either proliferation or differentiation medium for 28 days, after which they were stimulated either with or without hCG, forskolin or dbcAMP for 24 h to examine the increase in gene expression of steroidogenic enzymes using qPCR. In addition, testosterone, androstenedione and progesterone levels were measured in the culture medium. We also transplanted human PDGFRα⁺-sorted testicular interstitial cells into the testis of LuRKO mice. Serum was collected at several time points after transplantation, and testosterone was measured. Twenty weeks after transplantation testes were collected for histological examination.

MAIN RESULTS AND THE ROLE OF CHANCE

From primary cultured human testicular interstitial cells at Passage 3, we could obtain a population of HLA-A,B,C⁺/CD34⁻/PDGFRα⁺ cells by FACS. The sorted cells showed characteristics of MSC and were able to differentiate into adipocytes, chondrocytes and osteocytes. Upon directed differentiation into Leydig cells in vitro, we observed a significant increase in the expression of HSD3B2 and INSL3. After 24 h stimulation with forskolin or dbcAMP, a significantly increased expression of STAR and CYP11A1 was observed. The cells already expressed HSD17B3 and CYP17A1 before differentiation but the expression of these genes were not significantly increased after differentiation and stimulation. Testosterone levels could not be detected in the medium in any of the stimulation conditions, but after stimulation with forskolin or dbcAMP, androstenedione and progesterone were detected in culture medium. After transplantation of the human cells into the testes of LuRKO mice, no significant increase in serum testosterone levels was found compared to the controls. Also, no human cells were identified in the interstitium of mice testes 20 weeks after transplantation.

LARGE SCALE DATA

N/A

LIMITATIONS, REASONS FOR CAUTION

This study was performed using tissue from only four donors because of limitations in donor material. Because of the need of sufficient cell numbers, we first propagated cells to passage 3 before FACS of the desired cell population was performed. We cannot rule out this propagation of the cells resulted in loss of stem cell properties.

WIDER IMPLICATIONS OF THE FINDINGS

A lot of information on Leydig cell development is obtained from rodent studies, while the knowledge on human Leydig cell development is very limited. Our study shows that human testicular interstitial PDGFRα⁺ cells have different characteristics compared to rodent testicular PDGFRα⁺ cells in gene expression levels of steroidogenic enzymes and potential to differentiate in adult Leydig cells under comparable culture conditions. This emphasizes the need for confirming results from rodent studies in the human situation to be able to translate this knowledge to the human conditions, to eventually contribute to improvements of testosterone replacement therapies or establishing alternative cell therapies in the future, potentially based on SLCs.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by Amsterdam UMC, location AMC, Amsterdam, the Netherlands. All authors declare no competing interests.

Testosterone therapy in hypogonadal patients and the associated risks of cardiovascular events

Since the male secondary sex characters, libido and fertility are attributed to their major androgen hormone testosterone, the sub-optimum levels of testosterone in young adults may cause infertility and irregularities in their sexual behaviour. Such deficiency is often secondary to maladies involving testes, pituitary or hypothalamus that could be treated with an administration of exogenous testosterone. In the last few decades, the number of testosterone prescriptions has markedly increased to treat sub-optimal serum levels even though its administration in such conditions is not yet approved. On account of its associated cardiovascular hazards, the food and drug authority in the United States has issued safety alerts on testosterone replacement therapy (TRT). Owing to a great degree of conflict among their findings, the published clinical trials seem struggling in presenting a decisive opinion on the matter. Hence, the clinicians remain uncertain about the possible cardiovascular adversities while prescribing TRT in hypogonadal men. The uncertainty escalates even further while prescribing such therapy in older men with a previous history of cardiovascular ailments. In the current review, we analysed the pre-clinical and clinical studies to evaluate the physiological impact of testosterone on cardiovascular and related parameters. We have enlisted studies on the association of cardiovascular health and endogenous testosterone levels with a comprehensive analysis of epidemiological studies, clinical trials, and meta-analyses on the cardiovascular risk of TRT. The review is aimed to assist clinicians in making smart decisions regarding TRT in their patients.

Hypogonadism management and cardiovascular health

In the early days of its use, testosterone therapy faced skepticism regarding its safety and efficacy. After a converging consensus that testosterone therapy was safe and effective for the treatment of hypogonadism, several recent studies showed adverse cardiovascular outcomes associated with testosterone treatment, ultimately resulting in a mandated FDA label warning about the unknown safety of testosterone therapy. Given the clear efficacy of testosterone therapy in the treatment of hypogonadism, establishing the safety of this therapeutic tool is essential. This article summarizes the current evidence regarding the cardiovascular safety of testosterone therapy for the management of hypogonadism, as well as the proposed mechanisms that may explain testosterone's underlying effects.

Retinoic acid receptor antagonists for male contraception: current status†

Retinoic acid receptor alpha (RARA), a nuclear receptor protein, has been validated as a target for male contraception by gene knockout studies and also pharmacologically using a pan-retinoic acid receptor antagonist. Retinoic acid receptor alpha activity is indispensable for the spermatogenic process, and therefore its antagonists have potential as male contraceptive agents. This review discusses the effects of systematic dosing regimen modifications of the orally bioavailable and reversible pan-antagonist BMS-189453 as well as studies with the alpha-selective antagonists BMS-189532 and BMS-189614 in a murine model. We also provide an overview of structure-activity studies of retinoic acid receptor alpha antagonists that provide insight for the design of novel alpha-selective ligands.

In Experimental Dilated Cardiomyopathy Heart Failure and Survival Are Adversely Affected by a Lack of Sexual Interactions

Nearly one in three people in the U.S. will develop heart failure (HF), characterized by fluid retention (edema) in the lungs and elsewhere. This leads to difficult breathing, deterioration of physical capacity, restriction of normal activities and death. There is little data about the safety and effects of sexual interactions in patients with HF. We tested whether a lack of sexual interactions affected pathophysiological outcomes in a pre-clinical mouse model of dilated cardiomyopathy that recapitulates the progressive stages of human HF. Male mice were randomly given access to, or deprived from, sexual interactions with female mice, which were confirmed by videography and generation of offspring. Cohousing with access to sexual interactions markedly prolonged survival, while cohousing without access to sexual activity did not. Sexual interactions improved systolic function, reduced HF-associated edema, altered transcription of heart contractile protein genes and decreased plasma testosterone levels. To determine whether testosterone levels contributed to survival, testosterone levels were experimentally reduced. Reduction of testosterone levels significantly prolonged survival. Taken together, in mice with dilated cardiomyopathy, sexual activity altered cardiac contractile gene transcription, improved systolic function, reduced edema and prolonged survival which may be in part due to lower testosterone levels.

Effectiveness of testosterone therapy in hypogonadal patients and its controversial adverse impact on the cardiovascular system

Testosterone is the major male hormone produced by testicles which are directly associated with man's appearance and secondary sexual developments. Androgen deficiency starts when the male hormonal level falls from its normal range though, in youngsters, the deficiency occurs due to disruption of the normal functioning of pituitary, hypothalamus glands, and testes. Thus, testosterone replacement therapy was already known for the treatment of androgen deficiency with lesser risks of producing cardiovascular problems. Since from previous years, the treatment threshold in the form of testosterone replacement therapy has effectively increased to that extent that it was prescribed for those conditions which it was considered as inappropriate. However, there are some research studies and clinical trials available that proposed the higher risk of inducing cardiovascular disease with the use of testosterone replacement therapy. Thus under the light of these results, the FDA has published the report of the increased risk of cardiovascular disease with the increased use of testosterone replacement therapy. Nevertheless, there is not a single trial available or designed that could evaluate the risk of cardiovascular events with the use of testosterone replacement therapy. As a result, the use of testosterone still questioned the cardiovascular safety of this replacement therapy. Thus, this literature outlines the distribution pattern of disease by investigating the data and link between serum testosterone level and the cardiovascular disease, also the prescription data of testosterone replacement therapy patients and their tendency of inducing cardiovascular disease, meta-analysis and the trials regarding testosterone replacement therapy and its connection with the risks of causing cardiovascular disease and lastly, the possible effects of testosterone replacement therapy on the cardiovascular system. This study aims to evaluate the available evidence regarding the use of testosterone replacement therapy when choosing it as a treatment plan for their patients.

BMI1 promotes steroidogenesis through maintaining redox homeostasis in mouse MLTC-1 and primary Leydig cells

In males, aging is accompanied by decline in serum testosterone levels due to impairment of testicular Leydig cells. The polycomb protein BMI1 has recently been identified as an anti-aging factor. In our previous study, BMI1 null mice showed decreased serum testosterone and Leydig cell population, excessive oxidative stress and p16/p19 signaling activation. However, a cause-and-effect relationship between phenotypes and pathways was not investigated. Here, we used the rescue approach to study the role of oxidative stress or p16/p19 in BMI1-mediated steroidogenesis. Our results revealed that treatment with antioxidant NAC, but not down-regulation of p16/p19, largely rescued cell senescence, DNA damage and steroidogenesis in BMI1-deficient mouse MLTC-1 and primary Leydig cells. Collectively, our study demonstrates that BMI1 orchestrates steroidogenesis mainly through maintaining redox homeostasis, and thus, BMI1 may be a novel and potential therapeutic target for treatment of hypogonadism.

Understanding Erectile Dysfunction in Hypertensive Patients: The Need for Good Patient Management

Erectile dysfunction (ED) is defined as a man’s consistent or recurrent inability to attain and/or maintain penile erection enough for successful vaginal intercourse. ED affects a large part of the population, increasing its incidence with age and comorbidities. It is estimated by the year 2025, 322 million men will suffer from ED. Incidence of ED has been related not only to chronic diseases such as diabetes mellitus, metabolic syndrome, hyperlipidemia, psychiatric diseases or urinary tract diseases, but also to hypertension and especially to antihypertensive treatments. This review summarizes current knowledge about the management of ED in hypertensive men and its role as cardiovascular disease predictor.

A comparative analysis of human adult testicular cells expressing stem Leydig cell markers in the interstitium, vasculature, and peritubular layer

Background

Origin of human adult Leydig cells (ALCs) is not well understood. This might be partly due to limited data available on the identification and location of human precursor and stem Leydig cells (SLCs) which hampers the study on the development of ALCs.

Objectives

The aim of the present study was to investigate whether described human (PDGFRα, NGFR) and rodent (NES, PDGFRα, THY1, NR2F2) SLC markers are expressed by a common cell population within human adult testicular interstitial cells in vivo and before and after in vitro propagation.

Materials and methods

Immunohistochemical analyses were used to identify localization of human adult testicular interstitial cells expressing described SLC markers. Next, interstitial cells were isolated and cultured. The percentage of cells expressing one or more SLC markers was determined before and after culture using flow cytometry.

Results

NR2F2 and PDGFRα were present in peritubular, perivascular, and Leydig cells, while THY1 was expressed in peritubular and perivascular cells. Although NES and NGFR were expressed in endothelial cells, co‐localization with PDGFRα was found for both in vitro, although for NGFR only after culture. All marker positive cells were able to undergo propagation in vitro.

Discussion

The partly overlap in localization and overlap in expression in human testicular cells indicate that PDGFRα, NR2F2, and THY1 are expressed within the same ALC developmental lineage from SLCs. Based on the in vitro results, this is also true for NES and after in vitro propagation for NGFR.

Conclusion

Our results that earlier described SLC markers are expressed in overlapping human interstitial cell population opens up further research strategies aiming for a better insight in the Leydig cell lineage and will be helpful for development of strategies to cure ALC dysfunction.

Testosterone concentrations and risk of cardiovascular events in androgen-deficient men with atherosclerotic cardiovascular disease

BACKGROUND

Whether androgen deficiency among men increases the risk of cardiovascular (CV) events or is merely a disease marker remains a subject of intense scientific interest.

OBJECTIVES

Among male subjects in the AIM-HIGH Trial with metabolic syndrome and low baseline levels of high-density lipoprotein (HDL)-cholesterol who were randomized to niacin or placebo plus simvastatin, we examined the relationship between low baseline testosterone (T) concentrations and subsequent CV outcomes during a mean 3-year follow-up.

METHODS

In this post hoc analysis of men with available baseline plasma T concentrations, we examined the relationship between clinical/demographic characteristics and T concentrations both as a continuous and dichotomous variable (<300 ng/dL ["low T"] vs. ≥300 ng/dL ["normal T"]) on rates of pre-specified CV outcomes, using Cox proportional hazards models.

RESULTS

Among 2118 male participants in whom T concentrations were measured, 643 (30%) had low T and 1475 had normal T concentrations at baseline. The low T group had higher rates of diabetes mellitus, hypertension, elevated body mass index, metabolic syndrome, higher blood glucose, hemoglobin A1c, and triglyceride levels, but lower levels of both low-density lipoprotein and HDL-cholesterol, and a lower rate of prior myocardial infarction (MI). Men with low T had a higher risk of the primary composite outcome of coronary heart disease (CHD) death, MI, stroke, hospitalization for acute coronary syndrome, or coronary or cerebral revascularization (20.1%) compared with the normal T group (15.2%); final adjusted HR 1.23, P = .07, and a higher risk of the CHD death, MI, and stroke composite endpoint (11.8% vs. 8.2%; final adjusted HR 1.37, P = .04), respectively.

CONCLUSIONS

In this post hoc analysis, there was an association between low baseline testosterone concentrations and increased risk of subsequent CV events in androgen-deficient men with established CV disease and metabolic syndrome, particularly for the composite secondary endpoint of CHD death, MI, and stroke.

CONDENSED ABSTRACT

In this AIM-HIGH Trial post hoc analysis of 2118 men with metabolic syndrome and low HDL-cholesterol with available baseline plasma testosterone (T) samples, 643 males (30%) had low T (mean: 229 ng/dL) and 1475 (70%) had normal T (mean: 444 ng/dL) concentrations. The "low T" group had a 24% higher risk of the primary 5-component endpoint (20.1%) compared with the normal T group (15.2%); final adjusted HR 1.23, P = .07). There was also a 31% higher risk of the secondary composite endpoint: coronary heart disease death, myocardial infarction, and stroke (11.8% vs. 8.2%, final adjusted HR 1.37, P = .04) in the low vs. normal T group, respectively.

Testosterone deficiency syndrome: Diagnosis and treatment

The testosterone deficiency syndrome (TDS) is a very common clinical and biochemical condition that affects approximately 2-5% men over the age of 40. From a clinical point of view, it is usually associated with decreased sexual desire and activity, erectile dysfunction, low energy and mood swings, along with T<8-12 nmol/l levels. Questionnaires are not useful in screening but may be useful for diagnosis and follow-up. Its diagnosis requires the presentation of multiple hypogonadism symptoms together with two morning T tests below the acceptable limits. LH and SHBG levels can be useful to determine the cause and the free T level, respectively. Contraindications for treatment are active prostate cancer, stage IV heart failure, breast cancer, desired fertility and hematocrit values over 54%. Treatment is based on the cause of TDS, if any, along with testosterone supplementation. The objective is to achieve normal testosterone levels. Follow-up includes clinical history, analysis (PSA, T+SHBG, hematocrit, glucose and lipid profile) and rectal examination, 3, 6 and 12 months after beginning treatment.

Acute effects of the translocator protein drug ligand FGIN-1-27 on serum testosterone and luteinizing hormone levels in male Sprague-Dawley rats†

We reported that FGIN-1-27 (N,N-dihexyl-2-(4-fluorophenyl)indole-3-acetamide, FGIN), a synthetic ligand for translocator protein (TSPO, 18 kDa), increased serum testosterone levels in young and aged Brown Norway rats after its administration daily for 10 days. It is not known, however, how soon after treatment with FGIN serum testosterone rises, how long levels remain elevated after cessation of treatment, or whether the drug acts solely through TSPO. Adult Sprague-Dawley male rats received a single ip dose of FGIN (1 mg/kg BW). Serial blood samples were collected, and serum testosterone and luteinizing hormone (LH) were assessed hourly throughout 24 h. Testosterone concentration was maximal by 3 h, remained significantly higher than the controls at 10 h, and returned to the control level by 24 h. Consistent with the in vivo study, culturing isolated Leydig cells with either FGIN (40 μM) or LH (0.1 ng/ml) resulted in significantly increased testosterone production by 30 min, and the stimulatory effects persisted through 48 h. At a very early (15 min) treatment time, however, FGIN significantly increased testosterone production but LH had not yet done so. Surprisingly, in vivo treatment with FGIN not only increased serum testosterone but also serum LH concentration, raising the possibility that FGIN may increase serum testosterone concentration by dual mechanisms.

Sarcopenia: A Contemporary Health Problem among Older Adult Populations

Sarcopenia, a geriatric disease characterized by a progressive loss of skeletal muscle mass and loss of muscle function, constitutes a rising, often undiagnosed health problem. Its prevalence in the elderly population is largely considered variable, as it ranges from 5% to 50% depending on gender, age, pathological conditions as well as diagnostic criteria. There is no one unified approach of treatment or assessment, which makes sarcopenia even harder to assess. There is a pressing need to provide better diagnosis, diagnostics, prevention, and individualized health care. Physical activity and nutrition are the main studied ways to prevent sarcopenia, and they also offer better outcomes. This review aims to report the prevalence of sarcopenia in older adults, its etiology, prevention, and treatment techniques.

The effects of testosterone on bone health in males with testosterone deficiency: a systematic review and meta-analysis

BACKGROUND

Testosterone deficiency (TD) may induce a series of clinical symptoms. Studies have shown that testosterone supplementation may prevent these unfavourable symptoms and improve patients' quality of life. Given the conflicting findings across studies, this systematic review aims to evaluate the effects and risks associated with testosterone supplementation in middle-aged or aging males with TD.

METHODS

Electronic databases (MEDLINE, EMBASE, PubMed, and Cochrane. Library were searched to December 2019. The risk of bias of individual included studies and the quality of the aggregate evidence were assessed using the GRADE approach. Our primary outcome was bone mineral density (BMD). Meta-analyses were performed. This systematic review was reported according to the PRISMA statement.

RESULTS

A total of 52 randomized controlled trials (RCTs) were included. When compared with placebo, testosterone supplementation did not increase total BMD (short-term: 1081 participants, MD - 0.01 g/cm², 95% CI - 0.02 g/cm² to 0.01 g/cm²; long-term: 156 participants, MD 0.04 g/cm², 95% CI - 0.07 g/cm² to 0.14 g/cm²), lumbar spine, hip, or femur neck BMD. Furthermore, testosterone supplementation did not decrease the risk of falling or fracture. Lastly, it was found that testosterone supplementation did not increase the risk of cardiovascular events (1374 participants, RR 1.28, 95% CI 0.62 to 2.64), all-cause mortality (729 participants, RR 0.55, 95% CI 0.29 to 1.04), or prostatic events. However, testosterone supplementation may improve sexual function and quality of life (1328 participants, MD -1.32, 95% CI - 2.11 to - 0.52).

CONCLUSIONS

The effect of testosterone supplementation on BMD and the risk of falls or fracture remains inconclusive. However, supplementation may benefit patients in the areas of sexual function and quality of life without increasing the risk of cardiovascular events, all-cause mortality, or prostatic events. RCTs with a longer follow-up period are still required.

TRIAL REGISTRATION

We registered our protocol in PROSPERO (CRD42018109738).

Cardiovascular risk with androgen deprivation therapy

BACKGROUND

From the primary care perspective, many urologists and oncologists appear to be ignoring an FDA warning to assess patients' cardiovascular (CV) risk before instituting androgen deprivation therapy (ADT) with gonadotropin-releasing hormone (GnRH) agonists. A growing body of data suggest an association between ADT and CV/cardiometabolic risk, particularly for GnRH agonists.

METHODOLOGY

The author examined available evidence regarding CV side effects with GnRH agonists and antagonists to determine what urologists, medical oncologists, primary care physicians (PCPs) and patients need to know about these risks.

RESULTS

Data are inconclusive and somewhat conflicting-for example, both low testosterone and testosterone replacement have been associated with elevated CV risk. But the distinction between GnRH agonists and antagonists is becoming clearer, as agonists appear to be more strongly linked with CV risk, perhaps due to the transient testosterone surge they cause upon administration. Moreover, adverse CV events associated with GnRH agonists can emerge relatively quickly, within weeks to months. Conversely, two studies show that GnRH antagonists may significantly reduce CV risk compared to GnRH agonists.

CONCLUSIONS

Both GnRH agonists and antagonists carry some degree of CV risk. Although the risk appears to be lower with GnRH antagonists, urologists and oncologists should communicate with PCPs to determine patients' baseline CV risk levels before implementing ADT with either type of agent.

No evidence found for an association between trial characteristics and treatment effects in randomized trials of testosterone therapy in men: a meta-epidemiological study

OBJECTIVE

The objective of this study was to identify potential trial characteristics associated with reported treatment effect estimates in randomized trials of testosterone therapy in adult men.

STUDY DESIGN AND SETTING

This is a meta-epidemiological study. MEDLINE was searched for meta-analyses of randomized trials of testosterone therapy in men published between 2008 and 2018. Data on trial characteristics were extracted independently by two reviewers. The impact of trial characteristics on reported treatment effects was investigated using a two-step meta-analytic approach.

RESULTS

We identified 132 randomized trials, included in 19 meta-analyses, comprising data from 10,725 participants. None of the investigated design characteristics, including year of publication, sample size, trial registration status, center status, regionality, funding source, and conflict of interest were statistically significantly associated with reported treatment effects of testosterone therapy in men. Although trials rated at high risk of bias overall reported treatment effects that were 21% larger compared with trials rated at low risk of bias overall, the 95% confidence interval included the null (ratio of odds ratio: 0.79, 95% confidence interval: 0.60 to 1.03).

CONCLUSION

The present study found no clear evidence that trial characteristics are associated with treatment effects in randomized trials of testosterone therapy in men. To establish stronger evidence about the treatment effects of testosterone therapy in men, future randomized trials should not only be adequately designed but also transparently reported.

STUDY REGISTRATION

osf.io/x9g6m.

Testosterone deficiency in men with Type 2 diabetes: pathophysiology and treatment

Epidemiological studies consistently demonstrate that lowered serum testosterone is not only common in men with established Type 2 diabetes, but also predicts future diabetic risks and increased mortality. Preclinical studies report plausible mechanisms by which low testosterone could mediate dysglycaemia. Exogenous testosterone treatment consistently reduces fat mass, increases muscle mass and improves insulin resistance in some studies, but the majority of currently available randomized controlled trials (RCTs) do not report a consistent glycaemic benefit. In men with diabetes, testosterone treatment effects on androgen deficiency-like clinical features are inconsistent, and effects on sexual dysfunction may be attenuated compared with men without diabetes. The long-term risks of testosterone treatment in older men without medical disease of the hypothalamic-pituitary-testicular axis are not known. Current RCTs are not definitive, owing to their small size, short duration and enrolment of men with mostly relatively good baseline glycaemic control not specifically selected for the presence of androgen deficiency symptoms. Although large, well-designed clinical trials are needed, given the benefit-risk ratio of testosterone treatment is not well understood, routine serum testosterone testing or testosterone treatment of asymptomatic men with Type 2 diabetes is currently not recommended. Carefully selected, symptomatic men with low testosterone who are informed of the lack of high-level evidence regarding the long-term benefits and risks of this approach may be offered a trial of testosterone treatment in combination with lifestyle measures, weight loss and optimization of comorbidities.

Efficacy and Safety of Testosterone Treatment in Men: An Evidence Report for a Clinical Practice Guideline by the American College of Physicians

BACKGROUND

Testosterone treatment rates in adult men have increased in the United States over the past 2 decades.

PURPOSE

To assess the benefits and harms of testosterone treatment for men without underlying organic causes of hypogonadism.

DATA SOURCES

English-language searches of multiple electronic databases (January 1980 to May 2019) and reference lists from systematic reviews.

STUDY SELECTION

38 randomized controlled trials (RCTs) of at least 6 months' duration that evaluated transdermal or intramuscular testosterone therapies versus placebo or no treatment and reported prespecified patient-centered outcomes, as well as 20 long-term observational studies, U.S. Food and Drug Administration review data, and product labels that reported harms information.

DATA EXTRACTION

Data extraction by a single investigator was confirmed by a second, 2 investigators assessed risk of bias, and evidence certainty was determined by consensus.

DATA SYNTHESIS

Studies enrolled mostly older men who varied in age, symptoms, and testosterone eligibility criteria. Testosterone therapy improved sexual functioning and quality of life in men with low testosterone levels, although effect sizes were small (low- to moderate-certainty evidence). Testosterone therapy had little to no effect on physical functioning, depressive symptoms, energy and vitality, or cognition. Harms evidence reported in trials was judged to be insufficient or of low certainty for most harm outcomes. No trials were powered to assess cardiovascular events or prostate cancer, and trials often excluded men at increased risk for these conditions. Observational studies were limited by confounding by indication and contraindication.

LIMITATION

Few trials exceeded a 1-year duration, minimum important outcome differences were often not established or reported, RCTs were not powered to assess important harms, few data were available in men aged 18 to 50 years, definitions of low testosterone varied, and study entry criteria varied.

CONCLUSION

In older men with low testosterone levels without well-established medical conditions known to cause hypogonadism, testosterone therapy may provide small improvements in sexual functioning and quality of life but little to no benefit for other common symptoms of aging. Long-term efficacy and safety are unknown.

PRIMARY FUNDING SOURCE

American College of Physicians. (PROSPERO: CRD42018096585).

Monitoring testosterone replacement therapy with transdermal gel: when and how?

PURPOSE

Testosterone replacement therapy (TRT) is recommended for the treatment of most cases of male hypogonadism. Transdermal testosterone (T) gels are commonly used in clinical practice; however, there is little evidence concerning how to monitor dosage to bring and maintain serum T levels in the normal physiologic range.

METHODS

We examined 30 hypogonadal patients undergoing treatment with 40 mg/day transdermal 2% testosterone gel. After a week from treatment onset, all patients underwent a total of four measurements to assess serum total T, bioavailable T and free T at + 2 h (samples A and A') and + 23 h (samples B and B').

RESULTS

No significant difference was found concerning total, free and bioavailable T between the two samples taken at the same time points (A vs A' and B vs B'). A repeated-measures mixed effects regression model showed significantly lower serum levels of total, free and bioavailable T at + 23 h compared to + 2 h (total T, β = - 3.050 ± 0.704, p < 0.001; free T, β = - 85.187 ± 22.746, p < 0.001; bioavailable T, β = - 1.519 ± 0.497, p = 0.003) without a significant between-sample variability. Serum T > 3.5 ng/ml at + 2 h was reached in 21/30 patients (70%), but only 11 (36.7%) still had adequate serum T at + 23 h.

CONCLUSION

Assessment of TRT with transdermal gels at its peak and at its minimum could be useful in providing a finely tailored treatment for hypogonadal men, both preventing supra-physiological levels and maintaining adequate concentrations through the day.

Testosterone, testosterone therapy and prostate cancer

With prostate cancer not observed in eunuchs and total androgen suppression by castration an effective first-line treatment for advanced prostate cancer, the dramatic regression seen in tumour symptoms after castration, lead to the theory that high levels of circulating androgens were a risk factor for prostate cancer. This theory however, ignored the effects testosterone variations within a physiologic range could have on early tumour events and since the early 2000s, clinical evidence discounting testosterone as a linear mechanistic cause of prostate cancer growth mounted, with alternative mechanistic hypotheses such as the saturation model being proposed. Together with a growing understanding of the negative health effects and decreased quality of life in men with testosterone deficiency or hypogonadism, a paradigm shift away from testosterone as a prostate cancer inducer occurred allowing clinicians to use testosterone therapy as potential treatment for men with difficult and symptomatic hypogonadism that had been previously treated for prostate cancer. In this review we contextualise the idea of testosterone as a risk factor for prostate cancer inducement and compile the most current literature with regards to the influence of testosterone and testosterone therapy in prostate cancer.

Late-onset hypogonadism: a concept comes of age

The term Late-onset hypogonadism (LOH) was coined in 2002 and defined as a disease entity in the ISA, ISSAM, EAU, EAA and ASA endorsed Recommendations for Investigation, Treatment and Monitoring of LOH (2005 and 2008) as 'a clinical and biochemical syndrome associated with advancing age, characterized by symptoms and a deficiency in serum testosterone (T)'. LOH was classified as a combined primary and secondary hypogonadism since the endocrine capacity of the testes and the pituitary are impaired. Symptoms of LOH include loss of libido, erectile dysfunction, loss of muscle mass, increased body fat, anemia, osteoporosis, depressed mood, decreased vitality, sweating, and hot flushes. Since these symptoms may also have origins other than LOH, exclusion of other disease entities and subnormal serum T levels are considered prerequisites for the diagnosis and possible treatment of LOH. However, during following years these guidelines were often neglected and, especially in the USA, indiscriminate prescribing of T was widely practised so that the US FDA warned against such irresponsible behavior. In Europe, T prescribing remained largely restricted to LOH as defined above. Nevertheless, a discussion started whether LOH really exists or is only a consequence of age-related comorbidities. Numerous studies have helped to clarify the situation, in particular, the European Male Aging Study (EMAS) and the US-initiated 7 T trials. Consequently, the newest US Endocrine Society Practice Guideline on T treatment (2018) includes advanced age as a cause of organic hypogonadism and recommends that 'in men >65 years who have symptoms or conditions suggestive of T deficiency … and consistently and unequivocally low morning T concentrations we suggest that clinicians offer T therapy on an individualised basis after explicit discussion of the potential risks and benefits'. Thus, the concept of LOH as conceived two decades ago has weathered criticism and survived the times.