Beneficial and adverse effects of testosterone on the cardiovascular system in men

Cardiovascular safety of testosterone replacement therapy in men: an updated systematic review and meta-analysis

INTRODUCTION

The cardiovascular (CV) safety of testosterone (T) replacement therapy (TRT) is still conflicting. Recent data suggested a TRT-related increased risk of atrial fibrillation (AF). The aim of this study was to systematic review and meta-analyze CV risk related to TRT as derived from placebo controlled randomized trials (RCTs).

AREAS COVERED

An extensive Medline, Embase, and Cochrane search was performed. All placebo-controlled RCTs reporting data on TRT-related CV safety were considered. To better analyze the role of T on AF, population-based studies investigating the relationship between endogenous circulating T levels and AF incidence were also included and analyzed.

EXPERT OPINION

Out of 3.615, 106 studies were considered, including 8.126 subjects treated with TRT and 7.310 patients allocated to placebo. No difference between TRT and placebo was observed when major adverse CV events were considered. Whereas the incidence of non-fatal arrhythmias and AF was increased in the only trial considering CV safety as the primary endpoint, this was not confirmed when all other studies were considered (MH-OR 1.61[0.84;3.08] and 1.44[0.46;4.46]). Similarly, no relationship between endogenous T levels and AF incidence was observed after the adjustment for confounders Available data confirm that TRT is safe and it is not related to an increased CV risk.

The relationship between serum sex hormone and cardiac echocardiographic findings in healthy men

Serum sex hormones are known to be associated with cardiovascular disease (CVD), but effects in healthy men on cardiac function have not been well quantified. The authors sought to evaluate an association of sex hormones with cardiac structure and function. Study participants were 857 Korean men without significant cardiovascular diseases participating in the Healthy Twin Study. We estimated the associations of total testosterone (TT) and sex hormone-binding globulin (SHBG) with cardiac structure and function measured by echocardiography using a linear mixed regression model with consideration of random and fixed effects of covariates. The ratio of peak early diastolic velocity of mitral inflow over peak early diastolic mitral annular velocity (E/e') and left atrial volume index (LAVI), functional parameters reflecting left ventricle (LV) filling pressure, were inversely associated with TT even after further cross-adjustment for SHBG level. There was a positive association between LAVI and SHBG, regardless of TT adjustment. These findings suggest that serum testosterone level is positively associated with LV diastolic function independent of SHBG level.

A unique case of tachycardia-mediated cardiomyopathy in a patient misusing anabolic steroids

A 54-year-old male patient with history of anabolic androgenic steroid (AAS) misuse presented to the emergency department with new-onset atrial fibrillation and severely reduced ejection fraction. Cardiac catheterization revealed normal coronaries. He underwent cryo-balloon ablation with subsequent conversion to sinus rhythm. After appropriate guideline-directed medical management, ejection fraction improved on follow-up.

Risk for Venous Thromboembolism in Transgender Patients Undergoing Cross-Sex Hormone Treatment: A Systematic Review

BACKGROUND

Feminizing and masculinizing hormone treatments are established components of management in transgender patients. Exogenous hormones have been associated with hemostatic effects, which are well-studied in cis-gender individuals on hormone replacement therapy (HRT). Unfortunately, comprehensive understanding of their effects on venous thromboembolism (VTE) risk in the transgender population is lacking.

AIM

This manuscript aims to identify the risk of VTE among transgender individuals undergoing cross-sex hormone therapy.

METHODS

A Systematic review of the literature was performed in March 2020 for studies reporting VTE rates in transgender patients undergoing hormone treatment and rates in cis-gender patients on HRT. Data regarding demographics, hormone therapy, and VTE incidence were collected and pooled for analysis.

OUTCOME

The primary outcome of interest was the development of a VTE event in association with concurrent hormone administration.

RESULTS

Overall, 22 studies were included with 11 reporting VTE rates among transgender patients, 6 in cis-female patients, and 5 in cis-male patients. Data from 9,180 transgender patients (6,068 assigned male at birth [AMAB] and 3,112 assigned female at birth [AFAB]) undergoing hormone treatment and 103,713 cis-gender patients (18,748 female and 84,965 male) undergoing HRT were pooled. The incidence of VTE was higher in AMAB patients compared to AFAB patients (42.8 vs 10.8 VTE per 10,000 patient years; P = .02). The rate of VTE incidences in AMAB patients appears similar or higher than the rate demonstrated in cis-females on HRT. VTE incidence in AFAB patients, however, is similar to the published rates in cis-males on HRT.

CLINICAL IMPLICATIONS

AMAB patients on hormone therapy have higher VTE rates than AFAB patients. AMAB and AFAB patients may have similar VTE incidence to cis-female and cis-male patients on hormone replacement therapy, respectively.

STRENGTHS & LIMITATIONS

This is the first study to aggregate and quantify the development of VTE events in association with hormone therapy in transgender patients. It places these values in the context of rates published in more widely studied populations. It is limited by its retrospective data and heterogenic data.

CONCLUSION

Surgical planning regarding perioperative and postoperative VTE prophylaxis or cessation of hormone therapy should take into account each patient's Caprini risk assessment and the nature of each intervention. Kotamarti VS, Greige N, Heiman AJ, et al. Risk for Venous Thromboembolism in Transgender Patients Undergoing Cross-Sex Hormone Treatment: A Systematic Review. J Sex Med 2021;18:1280-1291.

Vasomotor action of androgens in the mesenteric artery of hypertensive rats. Role of perivascular innervation

Androgens may exert cardiovascular protective actions by regulating the release and function of different vascular factors. In addition, testosterone (TES) and its 5-reduced metabolites, 5α- and 5β-dihydrotestosterone (5α- and 5β-DHT) induce vasorelaxant and hypotensive effects. Furthermore, hypertension has been reported to alter the release and function of the neurotransmitters nitric oxide (NO), calcitonin gene-related peptide (CGRP) and noradrenaline (NA). Since the mesenteric arteries possess a dense perivascular innervation and significantly regulate total peripheral vascular resistance, the objective of this study was to analyze the effect of TES, 5α- and 5β-DHT on the neurogenic release and vasomotor function of NO, CGRP and NA. For this purpose, the superior mesenteric artery from male spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto (WKY) rats was used to analyze: (i) the effect of androgens (10 nM, incubated for 30 min) on the neurogenic release of NO, CGRP and NA and (ii) the vasoconstrictor-response to NA and the vasodilator responses to the NO donor, sodium nitroprusside (SNP) and exogenous CGRP. The results showed that TES, 5α- or 5β-DHT did not modify the release of NO, CGRP or NA induced by electrical field stimulation (EFS) in the arteries of SHR; however, in the arteries of WKY rats androgens only caused an increase in EFS-induced NO release. Moreover, TES, and especially 5β-DHT, increased the vasodilator response induced by SNP and CGRP in the arteries of SHR. These findings could be contributing to the hypotensive/antihypertensive efficacy of 5β-DHT previously described in conscious SHR and WKY rats, pointing to 5β- DHT as a potential drug for the treatment of hypertension.

CARDIOVASCULAR HEALTH MAINTENANCE IN AGING INDIVIDUALS: THE IMPLICATIONS FOR TRANSGENDER MEN AND WOMEN ON HORMONE THERAPY

OBJECTIVE

To review screening guidelines for cardiometabolic disease in aging patients and review literature describing the effect of hormone therapy (HT) on several key cardiometabolic processes to inform providers caring for older transgender individuals.

METHODS

A traditional literature review was performed using PubMed and Google Scholar databases.

RESULTS

The risk of cardiovascular disease increases with age. Exogenous sex hormones may interact with hormone-dependent metabolic pathways and affect some biochemical assays, but they do not necessarily impact clinical outcomes. While long-term HT is associated with an increased risk of some adverse cardiovascular outcomes, modern treatment regimens minimize this risk.

CONCLUSION

Screening for cardiometabolic derangements and risk reduction are important for all aging individuals. Currently, there is insufficient evidence to propose separate screening recommendations for transgender individuals on long-term HT. Aging transgender men and women should be monitored for cardiovascular disease in much the same way as their cisgender counterparts.

Effect of education about andropause health on level of the knowledge and attitude of men referring to the education and training retirement center of Shiraz

Introduction and objective: With the world's older population continuing to grow, andropause (male menopause or late-onset hypogonadism) is considered as one of the most important issues of this era. In this study, we aimed to assess the effect of andropause health education on the level of knowledge and attitude of retired men.Methods: This controlled trial was conducted on 80 retired men (40 in intervention group, 40 in control group), who had been employed by the Department of Education, Shiraz, Iran. Data collection tool was a 38-item questionnaire, designed by the researcher, on participants' knowledge and attitude about andropause. Data were analyzed using SPSS software, version 22 and statistical tests such as independent and paired t tests were used.Findings: There was no significant difference between the intervention and control groups before the intervention. There was a significant difference in knowledge and attitude scores in each group immediately and 1 month after the intervention. The mean score of knowledge in the intervention group increased from 2.92 ± 1.68 before to 16.22 ± 1.34 after the intervention, and the attitude score increased from 14.9 ± 1.08 to 28.52 ± 1.44. Comparison of the two groups and repeated score analysis showed that there was a significant difference between the two groups over the time (p < .001).Conclusion: Educational intervention improved the knowledge and attitude of retired men toward andropause, which can have a positive impact on the timely recognition and proper treatment of the complications of andropause.

Klinefelter syndrome and testosterone treatment: a national cohort study on thrombosis risk

OBJECTIVES

Klinefelter syndrome (KS), 47,XXY, can be viewed as a disease model for investigating the risk of thrombosis in male hypogonadism and the subsequent risk related to testosterone treatment. We describe rates of thrombotic risk factors, thrombosis and thrombosis mortality in KS and the association with testosterone treatment.

METHODS

National registry-based matched cohort study with follow-up from 1995 to 2016 set in Denmark. For the study, 1155 men with KS were each matched by year and month of birth to 100 men from the background population. First thrombotic events and thrombosis mortality was evaluated by event rates and hazard ratios (HRs) and by applying testosterone treatment as a time-dependent covariate.

RESULTS

The KS cohort had higher incidence of venous thromboembolism relative to the comparison cohort (HR, 3.95; 95% CI, 2.83-5.52). Total thrombotic deaths were increased in KS (HR, 1.76; 95% CI, 1.18-2.62), and all-cause mortality was increased in KS following arterial thrombosis (HR 1.73; 95% CI 1.22-2.47). Only 48.7% of men with KS redeemed prescriptions for testosterone. Untreated men with KS were on average born 12 years before those treated, and the majority of untreated men with KS with available biochemistry were hypogonadal. Testosterone treatment in KS was associated with a non-significant decrease in venous thromboembolism and thrombotic deaths.

CONCLUSION

Thrombosis and thrombotic deaths are increased in KS. Only half of the men with KS ever received testosterone treatment, despite overt hypogonadism in the non-treated. Testosterone treatment in Klinefelter syndrome was insignificantly associated with lower incidence rates of venous thrombosis and thrombotic deaths.

Resting heart rate is associated with metabolic syndrome and predicted 10-year risk of cardiovascular disease: a cross-sectional study

BACKGROUND

This study examined whether resting heart rate (RHR) was associated with metabolic syndrome (MetS) and the 10-year predicted risk of cardiovascular disease in a Chinese population.

METHODS

The associations of RHR with MetS and 10-year risk of atherosclerotic cardiovascular diseases (ASCVD) was examined in a cross-sectional study conducted in Shanghai, China (n = 9486).

RESULTS

Compared with individuals in the lowest RHR quintile (≤71 b.p.m.), those in the highest quintile (≥91 b.p.m.) had a higher prevalence of MetS (21.2% vs 32.6%, respectively; P < 0.001). Logistic regression analyses showed that the multivariate-adjusted odds ratio (OR) and 95% confidence interval (CI) for MetS was 1.13 (1.08-1.18) for each 10-b.p.m. increment of RHR (P < 0.0001). Furthermore, RHR was strongly associated with the prevalence of hypertension, high blood glucose, and dyslipidemia, but not with central obesity. A stronger association of RHR with MetS was observed among individuals aged <65 years, male, with a body mass index <24 kg/m² , without diabetes, hypertension, abnormal lipids, and insulin resistance than among their counterparts (P < 0.05 for all). A significantly higher 10-year risk for ASCVD was observed with each 10-b.p.m. increment in RHR in both men and women (ORs [95% CIs] 1.20 [1.07-1.33] and 1.28 [1.17-1.39], respectively; P_trend  = 0.002 and < 0.0001, respectively).

CONCLUSIONS

In this study, RHR was associated with a higher prevalence of MetS and elevated 10-year predicted risk of ASCVD in both Chinese men and women. Whether RHR may serve as an indicator for MetS among relatively healthy individuals requires further investigation.

TESTOSTERONE SUPPLEMENTATION AND RETINAL VASCULAR DISEASE

PURPOSE

To determine whether testosterone supplementation is associated with retinal artery occlusion (RAO) or retinal vein occlusion (RVO).

METHODS

Retrospective matched cohort study using data from a large national U.S. insurance database. The testosterone cohort consisted of all male patients who filled a prescription for testosterone from 2000 to 2013. Five controls were matched on age (±3 years), sex, race, and similar time in plan (±3 months) for every exposed patient. Exclusion occurred for <2 years in the plan, <1 eye care visit, medications known to affect androgen levels, and systemic diseases associated with occlusions or increased testosterone. Cox proportional hazard regression assessed the hazard of a new diagnosis of RAO or RVO while controlling for age, race, diabetes mellitus, and hypertension.

RESULTS

A total of 35,784 incident testosterone users were compared with 178,860 matched controls. Ninety-three (0.3%) RAOs and 50 (0.1%) RVOs were found in the testosterone cohort and contrasted with 316 (0.2%) RAOs and 232 (0.1%) RVOs in the control group. After multivariate analysis, testosterone supplementation significantly increased the hazard of RAO (hazard ratio: 1.43, 95% confidence interval: 1.12-1.81, P = 0.004), but not of RVO (hazard ratio: 1.03, 95% confidence interval: 0.74-1.42, P = 0.86).

CONCLUSION

Although the incidence of RAO and RVO is low in users of testosterone, supplementation therapy is associated with an increased hazard of RAO, but apparently not of RVO.

Aging and the Male Reproductive System

This narrative review presents an overview of current knowledge on fertility and reproductive hormone changes in aging men, the factors driving and modulating these changes, their clinical consequences, and the benefits and risks of testosterone (T) therapy. Aging is accompanied by moderate decline of gamete quality and fertility. Population mean levels show a mild total T decline, an SHBG increase, a steeper free T decline, and a moderate LH increase with important contribution of comorbidities (e.g., obesity) to these changes. Sexual symptoms and lower hematocrit are associated with low T and are partly responsive to T therapy. The relationship of serum T with body composition and metabolic health is bidirectional; limited beneficial effects of T therapy on body composition have only marginal effects on metabolic health and physical function. Skeletal changes are associated primarily with estradiol and SHBG. Cognitive decline is not consistently linked to low T and is not improved by T therapy. Although limited evidence links moderate androgen decline with depressive symptoms, T therapy has small beneficial effects on mood, depressive symptoms, and vitality in elderly patients with low T. Suboptimal T (and/or DHT) has been associated with increased risk of stroke, but not of ischemic heart disease, whereas an association with mortality probably reflects that low T is a marker of poor health. Globally, neither severity of clinical consequences attributable to low T nor the nature and magnitude of beneficial treatment effects justify the concept of some broadly applied "T replacement therapy" in older men with low T. Moreover, long-term safety of T therapy is not established.

African star apple fruit pulp-supplemented diet modulates fertility-related biomolecules in the testis and epididymis of high-fat diet/streptozotocin-induced diabetic rats

This study evaluated the modulatory effect of African star apple fruit (ASAF) pulp inclusive diet on biomolecules associated with reproductive function in the testis and epididymis of high-fat diet/streptozotocin-induced diabetic male rats. The rats were divided into seven groups: control, diabetic control, diabetic rats treated with metformin, diabetic rats served with diet having 5 and 10% ASAF, respectively, and control rats served with diet containing 5%, and 10% ASAF respectively for 14 days. There were noticeable decrease in sperm parameters, reproductive hormone, glycogen, nitric oxide, total thiol, nonprotein thiol levels, and testicular 3β- and 17β-hydroxysteroid dehydrogenase activities and concomitant increase in cholesterol, reactive oxygen species, malondialdehyde levels, and arginase activity compared to the control. Nevertheless, ASAFs reversed all these parameters toward the control levels. Therefore, these findings suggest that ASAF pulp-supplemented diet might be an active approach in controlling male reproductive dysfunction induced by diabetes. PRACTICAL APPLICATIONS: The results suggest that ASAF pulp-supplemented diet might be an active approach in controlling male reproductive dysfunction induced by diabetes through alterations in the levels of blood glucose, glycogen, cholesterol, nitric oxide, reproductive hormones, activities of steroidogenic enzymes, arginase, and sperm characteristics as well as the antioxidant status in the testes and epididymis.

Testosterone deficiency reduces the effects of late cardiac remodeling after acute myocardial infarction in rats

Testosterone is associated with an increased risk of coronary heart disease. This study evaluated cardiac remodeling 60 days after myocardial infarction (MI) in rats with testosterone deficiency. One week after castration, the animals underwent myocardial infarction. Rats were divided into four groups: orchidectomized (OCT); orchidectomized and infarcted (OCT+MI), MI and control (Sham). The myocyte cross-sectional area and the papillary muscle contractility were evaluated 8 weeks after MI. The coronary bed was perfused with Biodur E20 resin to evaluate the neovascularization after MI. Data were expressed as mean ± SEM followed by ANOVA. Castration reduced myocyte hypertrophy when compared to Sham and myocardial infarction alone as well as preserved the contraction force and activation time after myocardial infarction. After beta-adrenergic stimulation, activation and relaxation kinetics were less impaired in the OCT+MI group than in the MI group. Contraction force was preserved in the OCT+MI group after beta-adrenergic stimulation. Multiple scanning electronic microscope images were obtained to characterize changes in the coronary arteries. Capillary density index was increased in the MI and OCT+MI groups compared with control. The MI and OCT+MI groups were characterized by irregular vessel arrangements with distorted shape, abrupt changes in vessel direction, as well as abrupt changes in diameter after bifurcations when compared to Sham and OCT. The results indicated that testosterone deficiency attenuates adverse cardiac remodeling after MI. Novel findings in this study were that testosterone deficiency in rats, induced by castration, changes the later remodeling after MI, when compared with non castrated rats. The absence of this androgenous hormone seems to be benefic against pathological hypertrophy.

Testosterone, myocardial function, and mortality

The cardiovascular system is particularly sensitive to androgens, but some controversies exist regarding the effect of testosterone on the heart. While among anabolic abusers, cases of sudden cardiac death have been described, recently it was reported that low serum level of testosterone was correlated with increased risk of cardiovascular diseases (CVD) and mortality rate. This review aims to evaluate the effect of testosterone on myocardial tissue function, coronary artery disease (CAD), and death. Low testosterone level is associated with increased incidence of CAD and mortality. Testosterone administration in hypogonadal elderly men and women has a positive effect on cardiovascular function and improved clinical outcomes and survival time. Although at supraphysiologic doses, androgen may have a toxic effect, and at physiological levels, testosterone is safe and exerts a beneficial effect on myocardial function including mechanisms at cellular and mitochondrial level. The interaction with free testosterone and estradiol should be considered. Further studies are necessary to better understand the interaction mechanisms for an optimal androgen therapy in CVD.

Testosterone Therapy and Risk of Acute Myocardial Infarction in Hypogonadal Men: An Administrative Health Care Claims Study

BACKGROUND

There are some ongoing debates on the potential link between testosterone therapy (TT) and risk of acute myocardial infarction (MI).

AIM

To investigate the association between acute MI and TT use compared with non-use in men having documented hypogonadism (diagnostic International Classification of Diseases, Ninth Revision codes 257.2, 257.8, 257.9, 758.7) in patient claims records.

METHODS

This retrospective cohort study used a real-world US-based administrative health care claims database (MarketScan 2004-2013; Truven Health Analytics, Ann Arbor, MI, USA) to compare MI rates between TT-treated men and a cohort of untreated hypogonadal men matched by a calendar time-specific propensity score. Subgroup analyses were performed by route of administration, age, and prior cardiovascular disease (CVD).

OUTCOMES

Incidence rates of MI (per 1,000 person-years) and hazard ratio.

RESULTS

After 1:1 calendar time-specific propensity score matching, 207,176 TT-treated men and 207,176 untreated hypogonadal men were included in the analysis (mean age = 51.8 years). Incidence rates of MI were 4.20 (95% CI = 3.87-4.52) in the TT-treated cohort and 4.67 (95% CI = 4.43-4.90) in the untreated hypogonadal cohort. Cox regression model showed no significant association between TT use and MI when comparing TT-treated with untreated hypogonadal men overall (hazard ratio = 0.99, 95% CI = 0.89-1.09), by age, or by prior CVD. A significant association was observed when comparing a subgroup of injectable (short- and long-acting combined) TT users with untreated hypogonadal men (hazard ratio = 1.55, 95% CI = 1.24-1.93).

CLINICAL IMPLICATION

In this study, there was no association between TT (overall) and risk of acute MI.

STRENGTHS AND LIMITATIONS

Strengths included the use of a comprehensive real-world database, sophisticated matching based on calendar blocks of 6 months to decrease potential bias in this observational study, carefully chosen index dates for the untreated cohort to avoid immortal time bias, and implemented sensitivity analysis to further investigate the findings (stratification by administration route, age, and prior CVD). Key limitations included no information about adherence, hypogonadism condition based solely on diagnosis (no information on clinical symptoms or testosterone levels), lack of information on disease severity, inability to capture diagnoses, medical procedures, and medicine dispensing if corresponding billing codes were not generated and findings could contain biases or fail to generalize well to other populations.

CONCLUSION

This large, retrospective, real-world observational study showed no significant association between TT use and acute MI when comparing TT-treated with untreated hypogonadal men overall, by age, or by prior CVD; the suggested association between injectable TT and acute MI deserves further investigation. Li H, Mitchell L, Zhang X, et al. Testosterone Therapy and Risk of Acute Myocardial Infarction in Hypogonadal Men: An Administrative Health Care Claims Study. J Sex Med 2017;14:1307-1317.

Testosterone and androstanediol glucuronide among men in NHANES III

Background

Most of the androgen replacement therapies were based on serum testosterone and without measurements of total androgen activities. Whether those with low testosterone also have low levels of androgen activity is largely unknown. We hence examined the association between testosterone and androstanediol glucuronide (AG), a reliable measure of androgen activity, in a nationally representative sample of US men.

Methods

Cross-sectional analysis was based on 1493 men from the Third National Health and Nutrition examination Survey (NHANES III) conducted from 1988 to 1991. Serum testosterone and AG were measured by immunoassay. Kernel density was used to estimate the average density of serum AG concentrations by quartiles of testosterone.

Results

Testosterone was weakly and positively correlated with AG (correlation coefficient = 0.18). The kernel density estimates show that the distributions are quite similar between the quartiles of testosterone. After adjustment for age, the distributions of AG in quartiles of testosterone did not change. The correlation between testosterone and AG was stronger in men with younger age, lower body mass index, non-smoking and good self-rated health and health status.

Conclusions

Serum testosterone is weakly correlated with total androgen activities, and the correlation is even weaker for those with poor self-rated health. Our results suggest that measurement of total androgen activity in addition to testosterone is necessary in clinical practice, especially before administration of androgen replacement therapy.

Thromboembolism peaking 3 months after starting testosterone therapy: testosterone–thrombophilia interactions

We assessed time of thrombotic events (venous thromboembolism (VTE)) after starting testosterone therapy (TT) in 21 men who sustained 23 VTE. The density of thrombotic events was greatest at 3 months after starting TT, with a rapid decline in events by 10 months. The 21 cases with VTE on TT differed from 110 patient controls with unprovoked VTE, not taking TT (VTE-no TT) for Factor V Leiden heterozygosity (FVL) (33 per cent vs 13 per cent, P=0.037), for high lipoprotein (a) (Lp(a)) (55 per cent vs 17 per cent, P=0.012), and for the lupus anticoagulant (33 per cent vs 4 per cent, P=0.003). These differences between cases and VTE-no TT controls were independent of age and gender. TT can interact with underlying thrombophilia–hypofibrinolysis promoting VTE. We suggest that TT should not be started in subjects with known thrombophilia. Coagulation screening, particularly for the FVL , Lp(a), and the lupus anticoagulant should be considered before starting TT, to identify men at high VTE risk who have an adverse risk/benefit ratio for TT.

Walnut leaf extract acts as a fertility agent in male Wistar albino rats - A search for herbal male fertility enhancer

Background Walnut leaf is one of the many medicinal plants used in folklore as male fertility enhancers. The present work was therefore undertaken with an aim to scientifically validate this claim. As such, we evaluated the effect of the aqueous extract from walnut leaves on biomolecules related to fertility in adult male rats and its mode of action as fertility-enhancing agent. Methods Twenty-five rats were randomly divided into five groups of five animals each; Group 1 served as control and received normal (0.9%) saline only; Groups II, III, IV received 50, 500, 1,000 mg/kg body weight (BW) of T. conophorum leaf extract orally, while Group V served as standard and was given suspension of clomiphene citrate orally at the dose of 1.04 mg/kg/ml BW. The extract and drug were given daily and the experiment lasted for 21 consecutive days. Results The testicular biochemical parameters in treated groups showed significant (p<0.05) increase in lactate dehydrogenase activity activity, Glucose-6-phosphate dehydrogenase (G-6PDH) activity, glycogen content, 3β and 17β hydroxysteroid dehydrogenase activities and testicular and epididymal Zn and Se contents with a significant decrease in cholesterol content. A significant increase in testis weight and epididymis weight were also observed. Also, a significant (p<0.05) increase in the level of serum testosterone, luteinizing hormone (LH), follicle-stimulating hormone, sperm count, motility, viability and a decrease in sperm abnormality were observed in the various treated groups when compared with the control group. This increment was concentration dependent, while the extract at the highest concentration showed a more pronounced effect than the standard drug. Also, no sperm DNA fragmentation index was found in all the treatment groups. Photomicrographs from light and scanning electron microscopy showed large fenestrae of interstitial tissue, large fluid space and intact seminiferous epithelium layers fully packed with spermatogenic cells in treated groups than the control group. Conclusions The present study has demonstrated that Tetracarpidium conophorum leaf possesses fertility-enhancing property and have useful effects on spermatogenesis and sperm parameters in rats.

A higher score on the Aging Males' Symptoms scale is associated with insulin resistance in middle-aged men

An age-associated androgen decrease and its pathological conditions are defined as late-onset hypogonadism (LOH). Among the various symptoms associated with LOH, a visceral fat increase is strongly associated with relatively low levels of testosterone. However, few studies have investigated the relationship between the Aging Males' Symptoms (AMS) scores and metabolic abnormalities. Thus, we aimed to clarify this relationship by investigating the relationship between AMS scores and various markers in blood. During routine health examinations in 241 middle-aged males (52.7±7.5 years of age, mean±SD), 150 males (62.2%) displayed higher AMS values than normal. No statistical association was observed between total AMS scores and any testosterone value. All mental, physical and sexual AMS subscales were significantly positively correlated with insulin levels and HOMA-IR. Only sexual subscale scores were significantly inversely associated with free or bioavailable testosterone level. Males with insulin resistance (HOMA-IR≥2.5) demonstrated significantly higher AMS scores than those with normal insulin sensitivity (HOMA-IR<2.5). AMS values were positively correlated with fasting blood glucose, insulin and HOMA-IR values. Interestingly, univariate and multivariate analyses revealed that HOMA-IR≥2.5 was a significant predictor for detection of moderately severe AMS values (AMS≥37), whereas AMS≥37 was not a predictor of metabolic syndrome by International Diabetes Federation (IDF) criterion. In conclusion, almost 60% of healthy male subjects displayed abnormal AMS scores. AMS values were not associated with testosterone values but rather were related to insulin resistance, particularly in subjects with moderately severe AMS values. Insulin resistance-related general unwellness might be reflected by AMS values.

Effects of Saikokaryukotsuboreito on Spermatogenesis and Fertility in Aging Male Mice

Background:

Aspermia caused by exogenous testosterone limit its usage in late-onset hypogonadism (LOH) patients desiring fertility. Saikokaryukotsuboreito (SKRBT) is reported to improve serum testosterone and relieve LOH-related symptoms. However, it is unclear whether SKRBT affects fertility. We aimed to examine the effects of SKRBT on spermatogenesis and fertility in aging male mice.

Methods:

Thirty aging male mice were randomly assigned to three groups. Mice were orally administered with phosphate-buffer solution or SKRBT (300 mg/kg, daily) or received testosterone by subcutaneous injections (10 mg/kg, every 3 days). Thirty days later, each male mouse was mated with two female mice. All animals were sacrificed at the end of 90 days. Intratesticular testosterone (ITT) levels, quality of sperm, expression of synaptonemal complex protein 3 (SYCP3), and fertility were assayed.

Results:

In the SKRBT-treated group, ITT, quality of sperm, and expression of SYCP3 were all improved compared with the control group (ITT: 85.50 ± 12.31 ng/g vs. 74.10 ± 11.45 ng/g, P = 0.027; sperm number: [14.94 ± 4.63] × 10⁶ cells/ml vs. [8.79 ± 4.38] × 10⁶ cells/ml, P = 0.002; sperm motility: 43.16 ± 9.93% vs. 33.51 ± 6.98%, P = 0.015; the number of SYCP3-positive cells/tubule: 77.50 ± 11.01 ng/ml vs. 49.30 ± 8.73 ng/ml, P < 0.001; the expression of SYCP3 protein: 1.23 ± 0.09 vs. 0.84 ± 0.10, P < 0.001), but fertility was not significantly changed (P > 0.05, respectively). In the testosterone-treated group, ITT, quality of sperm, and expression of SYCP3 were markedly lower than the control group (ITT: 59.00 ± 8.67, P = 0.005; sperm number: [4.34 ± 2.45] × 10⁶ cells/ml, P = 0.018; sperm motility: 19.53 ± 7.69%, P = 0.001; the number of SYCP3-positive cells/tubule: 30.00 ± 11.28, P < 0.001; the percentage of SYCP3-positive tubules/section 71.98 ± 8.88%, P = 0.001; the expression of SYCP3 protein: 0.71 ± 0.09, P < 0.001), and fertility was also suppressed (P < 0.05, respectively).

Conclusion:

SKRBT had no adverse effect on fertility potential in aging male mice.

Testosterone replacement therapy and the heart: friend, foe or bystander?

The role of testosterone therapy (TTh) in cardiovascular disease (CVD) outcomes is still controversial, and it seems will remain inconclusive for the moment. An extensive body of literature has investigated the association of endogenous testosterone and use of TTh with CVD events including several meta-analyses. In some instances, a number of studies reported beneficial effects of TTh on CVD events and in other instances the body of literature reported detrimental effects or no effects at all. Yet, no review article has scrutinized this body of literature using the magnitude of associations and statistical significance reported from this relationship. We critically reviewed the previous and emerging body of literature that investigated the association of endogenous testosterone and use of TTh with CVD events (only fatal and nonfatal). These studies were divided into three groups, “beneficial (friendly use)”, “detrimental (foe)” and “no effects at all (bystander)”, based on their magnitude of associations and statistical significance from original research studies and meta-analyses of epidemiological studies and of randomized controlled trials (RCT’s). In this review article, the studies reporting a significant association of high levels of testosterone with a reduced risk of CVD events in original prospective studies and meta-analyses of cross-sectional and prospective studies seems to be more consistent. However, the number of meta-analyses of RCT’s does not provide a clear picture after we divided it into the beneficial, detrimental or no effects all groups using their magnitudes of association and statistical significance. From this review, we suggest that we need a study or number of studies that have the adequate power, epidemiological, and clinical data to provide a definitive conclusion on whether the effect of TTh on the natural history of CVD is real or not.

Testosterone treatment and risk of venous thromboembolism: population based case-control study

OBJECTIVE

 To determine the risk of venous thromboembolism associated with use of testosterone treatment in men, focusing particularly on the timing of the risk.

DESIGN

 Population based case-control study SETTING:  370 general practices in UK primary care with linked hospital discharge diagnoses and in-hospital procedures and information on all cause mortality.

PARTICIPANTS

 19 215 patients with confirmed venous thromboembolism (comprising deep venous thrombosis and pulmonary embolism) and 909 530 age matched controls from source population including more than 2.22 million men between January 2001 and May 2013.

EXPOSURE OF INTEREST

 Three mutually exclusive testosterone exposure groups were identified: current treatment, recent (but not current) treatment, and no treatment in the previous two years. Current treatment was subdivided into duration of more or less than six months.

MAIN OUTCOME MEASURE

 Rate ratios of venous thromboembolism in association with current testosterone treatment compared with no treatment were estimated using conditional logistic regression and adjusted for comorbidities and all matching factors.

RESULTS

 The adjusted rate ratio of venous thromboembolism was 1.25 (95% confidence interval 0.94 to 1.66) for current versus no testosterone treatment. In the first six months of testosterone treatment, the rate ratio of venous thromboembolism was 1.63 (1.12 to 2.37), corresponding to 10.0 (1.9 to 21.6) additional venous thromboembolisms above the base rate of 15.8 per 10 000 person years. The rate ratio after more than six months' treatment was 1.00 (0.68 to 1.47), and after treatment cessation it was 0.68 (0.43 to 1.07). Increased rate ratios within the first six months of treatment were observed in all strata: the rate ratio was 1.52 (0.94 to 2.46) for patients with pathological hypogonadism and 1.88 (1.02 to 3.45) for those without it, and 1.41 (0.82 to 2.41) for those with a known risk factor for venous thromboembolism and 1.91 (1.13 to 3.23) for those without one.

CONCLUSIONS

 Starting testosterone treatment was associated with an increased risk of venous thromboembolism, which peaked within six months and declined thereafter.

Neutral associations of testosterone, dihydrotestosterone and estradiol with fatal and non-fatal cardiovascular events, and mortality in men aged 17-97 years

CONTEXT

Lower testosterone (T) is associated with poorer health outcomes in older men, however, the relationship between T, dihydrotestosterone (DHT) and estradiol (E2) with cardiovascular disease (CVD) in younger to middle-aged men remains unclear.

OBJECTIVES

We assessed associations between endogenous sex hormones with mortality (all-cause and CVD) and CVD events, in a cohort of men aged 17-97 years.

PARTICIPANTS AND METHODS

Sex hormones were assayed using mass spectrometry in 2143 men from the 1994/5 Busselton Health Survey. Outcomes to December 2010 were analysed.

RESULTS

Of the 1804 men included in the analysis, mean age was 50·3 ± 16·8 years and 68·9% of men were aged <60. Mean follow-up period was 14·9 years. There were 319 deaths, 141 CVD deaths and 399 CVD events. Compared to the full cohort, men who died had lower baseline T (12·0 ± 4·4 vs 13·6 ± 4·9 nmol/l), free T (181·9 ± 52·9 vs 218·3 ± 63·8 pmol/l) and DHT (1·65 ± 0·64 vs 1·70 ± 0·72 nmol/l), but higher E2 (64·0 ± 32 vs 60·1 ± 30·2 pmol/l). After adjustment for risk factors, T was not associated with mortality (adjusted HR = 0·90, 95% CI 0·79-1·04; P = 0·164 for every increase in 1 SD of T), CVD deaths (adjusted HR = 1·04, 95% CI 0·84-1·29; P = 0·708) or CVD events (adjusted HR = 1·03, 95% CI 0·92-1·15, P = 0·661). No associations were found for free T, DHT or E2. Results were similar for men older and younger than 60 years.

CONCLUSIONS

In predominantly middle-aged men, T, DHT and E2 do not influence mortality or CVD outcomes. This neutral association of hormones with CVD contrasts with prior studies of older men.

Sex steroids in relation to cardiac structure and function in men

The prevalence of testosterone substitution as well as of androgen deprivation therapy in men is increasing. This review aims to summarise available knowledge of the effects of sex steroids on cardiac structure and function in men. MEDLINE was searched through PubMed. Original studies, systematic reviews and meta-analyses, and relevant citations were screened. A short-term hormonal intervention study in healthy young men with respect to echocardiographic parameters of structure and function was performed. Preclinical research provides sufficient evidence for the heart as a substrate for sex hormones. In animals, administration of oestradiol appears to have beneficial effects on cardiac structure and function, whereas administration of testosterone to noncastrated animals adversely affects cardiac function. However, the effects of sex steroids on cardiac function and structure appear more heterogeneous in human observational studies while comparative, prospective studies in humans are lacking. It is concluded that although effects of testosterone substitution as well as of androgen deprivation on cardiac structure and function can be expected based on pre-clinical research, there exists an important knowledge gap of the effects of hormonal intervention in men. As such, there is a need to address this question in future prospective intervention trials.

Single-nucleotide polymorphism in the 5-α-reductase gene (SRD5A2) is associated with increased prevalence of metabolic syndrome in chemotherapy-treated testicular cancer survivors

PURPOSE

Chemotherapy-treated testicular cancer survivors are at risk for development of the metabolic syndrome, especially in case of decreased androgen levels. Polymorphisms in the gene encoding steroid 5-α-reductase type II (SRD5A2) are involved in altered androgen metabolism. We investigated whether single-nucleotide polymorphisms (SNPs) rs523349 (V89L) and rs9282858 (A49T) in SRD5A2 are associated with cardiometabolic status in testicular cancer survivors.

METHODS

In 173 chemotherapy-treated testicular cancer survivors, hormone levels and cardiometabolic status were evaluated cross-sectionally (median 5 years [range 3-20] after chemotherapy) and correlated with SNPs in SRD5A2.

RESULTS

The metabolic syndrome was more prevalent in survivors who were homozygous or heterozygous variant for SRD5A2 rs523349 compared to wild type (33% versus 19%, P = 0.032). In particular, patients with lower testosterone levels (<15 nmol/l) and a variant genotype showed a high prevalence of the metabolic syndrome (66.7%). Mean intima-media thickness of the carotid artery and urinary albumin excretion, both markers of vascular damage, were higher in the group of survivors homozygous or heterozygous variant for rs523349 (0.62 versus 0.57 mm, P = 0.026; 5.6 versus 3.1 mg/24 h, P = 0.017, respectively). No association was found between cardiometabolic status and SNP rs9282858 in SRD5A2.

CONCLUSION

Metabolic syndrome develops more frequently in testicular cancer survivors homozygous or heterozygous variant for SNP rs523349 in SRD5A2. Altered androgen sensitivity appears to be involved in the development of adverse metabolic and vascular changes in testicular cancer survivors and is a target for intervention.

Effect of testosterone treatment on cardiac biomarkers in a randomized controlled trial of men with type 2 diabetes

OBJECTIVE

To assess the effect of testosterone treatment on cardiac biomarkers in men with type 2 diabetes (T2D).

DESIGN

Randomized double-blind, parallel, placebo-controlled trial.

PATIENTS

Men aged 35-70 years with T2D and a total testosterone level ≤12·0 nmol/l (346 ng/dl) at high risk of cardiovascular events, median 10-year United Kingdom Prospective Diabetes Study (UKPDS) coronary heart disease (CHD) risk 21% (IQR 16%, 27%). Eighty-eight participants were randomly assigned to 40 weeks of intramuscular testosterone undecanoate (n = 45) or matching placebo (n = 43).

MAIN OUTCOME MEASURES

N-terminal pro B-type natriuretic peptide (NT-proBNP) and high-sensitivity cardiac troponin T (hs-cTnT).

RESULT

Testosterone treatment reduced NT-proBNP (mean adjusted difference (MAD) in change over 40 weeks across the testosterone and placebo groups, -17·9 ng/l [95% CI -32·4, -3·5], P = 0·047), but did not change hs-cTnT (MAD, 0·41 ng/l (95% CI -0·56, 1·39), P = 0·62). Six men, three in each group experienced an adverse cardiac event, displaying already higher baseline NT-proBNP (P < 0·01) and hs-cTnT levels (P = 0·01). At baseline, 10-year UKPDS CHD risk was associated positively with NT-proBNP (τ = 0·21, P = 0·004) and hs-cTnT (τ = 0·23, P = 0·003) and inversely with testosterone (total testosterone τ = -0·18, P = 0·02, calculated free testosterone τ = -0·19, P = 0·01), but there was no significant association between testosterone and cardiac biomarkers (P > 0·05).

CONCLUSIONS

In this trial of men with T2D and high cardiovascular risk, testosterone treatment reduced NT-proBNP and did not change hs-cTnT. Further studies should determine whether men with increased cardiac biomarkers prior to testosterone therapy are at higher risk of testosterone treatment-associated adverse cardiac events.

Testosterone: a hormone preventing cardiovascular disease or a therapy increasing cardiovascular events?

Decreasing testosterone levels with ageing is a well-known condition in older men named 'low T', 'manopause', or hypogonadism. Observational studies suggested an association between low endogenous testosterone levels and a high cardio-metabolic profile (increased blood pressure, dyslipidaemia, insulin resistance, atherosclerosis, thrombosis), as well as a modest increase in total and cardiovascular (CV) mortality. Controversies persist regarding the need for screening 'low T' in older men, as well as what precisely should be the indication(s) for testosterone replacement therapy. So far, no data have shown that normalization of testosterone levels reduce CV events. Although testosterone replacement therapy seems to have beneficial effects on male quality of life or physical condition, some data suggest serious adverse events, such as CV events. In addition, there is a lack of consensus on the threshold for treatment indication in men with non-specific symptoms or borderline levels of testosterone. Available data from clinical practice setting suggest an increase in testosterone prescription over time and possible overtreatment. In recent years, pharmaceutical companies have promoted 'low T' as a treatable disease, suggesting that testosterone replacement may help restore energy, positive mood and sexuality, and despite ageing. Currently, well-designed, adequately powered randomized controlled trials are needed to assess the impact of testosterone replacement therapy on CV clinically relevant CV outcomes within age-specific ranges to strengthen the evidence for clinical practice guidelines.

Testosterone and cardiovascular disease risk

PURPOSE OF REVIEW

Ageing is accompanied by a reduction in circulating testosterone and progressive accumulation of medical morbidities. There is an intense debate whether low testosterone contributes to ill-health as opposed to being a biomarker for its presence. Prescriptions for testosterone are rising on a background of concern over potential adverse effects. This review examines evidence relating androgens to cardiovascular risk in older men.

RECENT FINDINGS

Observational studies show lower risk of cardiovascular events in older men with higher testosterone, and lower mortality from ischaemic heart disease in men with higher concentrations of its more potent androgenic metabolite dihydrotestosterone. However, randomized controlled trials of testosterone supplementation have been underpowered for the outcome of cardiovascular events. Recent meta-analyses have reached contrasting conclusions regarding cardiovascular adverse events associated with testosterone therapy. Retrospective studies of prescription databases have produced controversial and conflicting results.

SUMMARY

Additional randomized controlled trials are required to clarify the role of testosterone supplementation in older men in the absence of pituitary or gonadal disease. Pending such studies, testosterone therapy should be considered in androgen-deficient men, with evaluation of potential benefits and risks.

Roles of Testosterone Replacement in Cardiac Ischemia-Reperfusion Injury

Testosterone is an anabolic steroid hormone, which is the major circulating androgen hormone in males. Testosterone levels decreasing below the normal physiological levels lead to a status known as androgen deficiency. Androgen deficiency has been shown to be a major risk factor in the development of several disorders, including obesity, metabolic syndrome, and ischemic heart disease. In the past decades, although several studies from animal models as well as clinical studies demonstrated that testosterone exerted cardioprotection, particularly during ischemia-reperfusion (I/R) injury, other preclinical and clinical studies have shown an inverse relationship between testosterone levels and cardioprotective effects. As a result, the effects of testosterone replacement on the heart remain controversial. In this review, reports regarding the roles of testosterone replacement in the heart following I/R injury are comprehensively summarized and discussed. At present, it may be concluded that chronic testosterone replacement at a physiological dose demonstrated cardioprotective effects, whereas acute testosterone replacement can cause adverse effects in the I/R heart.

Low Serum Testosterone Levels Are Associated with Elevated Urinary Mandelic Acid, and Strontium Levels in Adult Men According to the US 2011-2012 National Health and Nutrition Examination Survey

BACKGROUND

Little is known regarding the effects of environmental exposure of chemicals on androgenic system in the general population. We studied 5,107 subjects included in the National Health and Nutrition Examination Survey (2011-2012).

METHODS

Urinary, serum, and blood levels of 15 subclasses comprising 110 individual chemicals were analyzed for their association with serum testosterone levels. The subjects were divided into high and low testosterone groups according to the median testosterone concentration (374.51 ng/dL). Odds ratios (ORs) of individual chemicals in association with testosterone were estimated using logistic regression after adjusting for age, ethnicity, cotinine, body mass index, creatinine, alcohol, and the poverty income ratio.

RESULTS

Adjusted ORs for the highest versus lowest quartiles of exposure were 2.12 (95% CI: 1.07, 4.21; Ptrend = 0.044), 1.84 (95% CI: 1.02, 3.34; Ptrend = 0.018) for the association between urinary mandelic acid, and strontium quartiles with low testosterone concentrations in adult men, respectively. However, no association was observed for the remaining chemicals with testosterone.

CONCLUSIONS

The National Health and Nutrition Examination Survey data suggest that elevations in urinary mandelic acid, and strontium levels are negatively related to low serum testosterone levels in adult men.

Endogenous testosterone and its relationship to preclinical and clinical measures of cardiovascular disease in the atherosclerosis risk in communities study

CONTEXT

Epidemiologic studies suggest that endogenous testosterone (T) levels in males may be implicated in cardiovascular disease (CVD), however further clarification is needed.

OBJECTIVE

We assessed the cross-sectional relationship between endogenous plasma T and mean carotid intima media thickness (cIMT), and the longitudinal relationship with incident clinical CVD events, cardiac mortality, and all-cause mortality using male participants in the Atherosclerosis Risk in Communities (ARIC) study.

DESIGN

This study involved a subset of men from visit 4 of the ARIC study.

SETTING

The study was conducted in a community based cohort.

PARTICIPANTS

Males who provided a morning blood sample excluding those taking androgen therapy, with prevalent coronary heart disease (CHD), stroke, or heart failure (HF) (n = 1558).

INTERVENTION

None.

MAIN OUTCOME MEASURES

Plasma T by liquid chromatography mass spectrometry and carotid IMT using high resolution B-mode ultrasound were obtained at visit 4. Incident CHD, HF, cardiac mortality, and all-cause mortality were identified by surveillance through 2010 (median 12.8 years).

RESULTS

Lower T was significantly associated with higher body mass index, greater waist circumference, diabetes, hypertension, lower HDL, and never smoking (P = 0.01). T was not associated with mean cIMT in unadjusted or adjusted analyses. Following multivariable adjustment, there was no association of quartile (Q) of T with incident CHD [hazard ratio (HR) = 0.87 (95% CI = 0.60-1.26) for Q1; 0.97 (95% CI = 0.69-1.38) for Q2; 0.97 (95% CI = 0.69-1.36) for Q3 compared to reference of Q4] or for incident HF [HR = 0.77 (95% CI = 0.46-1.29) for Q1; 0.72 (95% CI = 0.43-1.21) for Q2; 0.87 (95% CI = 0.53-1.42) for Q3 compared to reference of Q4]. Similarly there was no association of Q of T with mortality or cardiac-associated mortality.

CONCLUSIONS

Low male plasma T is cross-sectionally associated with key CVD risk factors, but after adjustment there was no association with mean cIMT, incident cardiac events, or mortality. Our results are reassuring that neither high nor low T levels directly predict atherosclerosis, but are a marker for other cardiovascular risk factors.

Andropause - state of the art 2015 and review of selected aspects

The term ‘male menopause’ was first used in 1944 to describe various complaints of ageing men which at least partially mirrored the climacteric symptoms in women. Continuous research resulted in the evolution of opinions about the nature of these complaints, from the clinical syndrome, diagnosed with the use of disease-targeted questionnaires, to a well-defined clinical and biochemical syndrome. The pathophysiological causes – gonad ageing (with a compensatory rise in luteinizing hormone), age-related increase in serum sex hormone-binding globulin (SHBG) levels, the role of visceral adipose tissue as a place for aromatization of androgen to estrogen, and lower sensitivity of testosterone receptors – have been described. However, no consensus was reached as far as the definition, incidence, treatment, and especially testosterone therapy, are concerned. Our review presents the current standpoints, indicating the predictive role of late-onset hypogonadism (LOH) in evaluating male health as well as the current literature reports on the risks and benefits of using testosterone therapy.

Effect of testosterone deficiency on cholesterol metabolism in pigs fed a high-fat and high-cholesterol diet

Background

Testosterone deficiency is associated with increased serum cholesterol levels. However, how testosterone deficiency precisely affects cholesterol metabolism remains unclear. Therefore, in the current study, we examined the effect of testosterone deficiency on cholesterol metabolism and liver gene expression in pigs fed a high-fat and high-cholesterol (HFC) diet.

Methods

Sexually mature male miniature pigs (6–7 months old) were randomly divided into 3 groups as follows: intact male pigs fed an HFC diet (IM + HFC), castrated male pigs fed an HFC diet (CM + HFC), and castrated pigs with testosterone replacement fed an HFC diet (CM + HFC + T). Serum testosterone levels and lipid profiles were measured, and gene expression levels associated with hepatic cholesterol metabolism were determined. Furthermore, total hepatic cholesterol contents and the activities of enzymes mediating hepatic cholesterol metabolism were measured.

Results

Serum testosterone levels were significantly decreased in CM + HFC pigs, and testosterone replacement attenuated castration-induced testosterone deficiency. Castration significantly increased the serum levels of total cholesterol, low-density lipoprotein cholesterol and triglycerides, as well as hepatic lipid contents in pigs fed an HFC diet. Compared with IM + HFC and CM + HFC + T pigs, low-density lipoprotein receptor (LDLR) mRNA expression and protein levels were significantly decreased in the livers of CM + HFC pigs. In contrast, we found that compared with IM + HFC pigs, hepatic proprotein convertase subtilisin/kexin type 9 (PCSK9) mRNA and serum PCSK9 protein levels were significantly increased in CM + HFC pigs. Moreover, testosterone treatment reversed the increase in PCSK9 expression in CM + HFC pigs. However, neither castration nor testosterone replacement affected the expression of the other hepatic genes that were tested.

Conclusions

This study demonstrated that castration-induced testosterone deficiency caused severe hypercholesterolemia in pigs fed an HFC diet; furthermore, these effects could be reversed by testosterone replacement therapy. Altered hepatic PCSK9 and LDLR expression, resulting in reduced LDL-cholesterol clearance, may contribute to the increased serum cholesterol levels induced by testosterone deficiency and an HFC diet. These results deepen our understanding of the underlying molecular mechanisms that mediate the effects of testosterone deficiency on cholesterol metabolism.

Testosterone, dihydrotestosterone and estradiol are differentially associated with carotid intima-media thickness and the presence of carotid plaque in men with and without coronary artery disease

Clarifying the relationship of sex hormones to preclinical atherosclerosis could illuminate pathways by which androgens are associated with cardiovascular events and mortality. Our aim was to determine hormone profiles associated with carotid intima-media thickness (CIMT) and carotid atheroma, in men with and without known coronary artery disease (CAD). We included 492 community-based men aged 20-70 years (Group A) and 426 men with angiographically proven CAD aged <60 years (Group B). Fasting early morning sera were assayed for testosterone (T), dihydrotestosterone (DHT) and estradiol (E2) using mass spectrometry. CIMT and carotid plaque were assessed ultrasonographically. Mean (±SD) age was Group A: 53.8±12.6 and Group B: 49.6±5.1 years. Higher T was associated with reduced CIMT (-0.011 mm per 1-SD increase, p=0.042) and lower prevalence of carotid plaque (odds ratio [OR] per 1-SD increase, 0.68, p=0.012) in Group A, but not B. E2 was associated with increased CIMT in Group A (0.013 mm, p=0.011) but not B. Higher DHT and E2 were associated with reduced carotid plaque in Group B (DHT: OR=0.77, p=0.024; E2: OR=0.75, p=0.008), but not A. In community-dwelling men, higher T is associated with favourable CIMT and lower prevalence of carotid plaque, while higher E2 is associated with worse CIMT. In men with CAD, higher DHT or E2 are associated with less carotid plaque. T, DHT and E2 are differentially associated with preclinical carotid atherosclerosis in a cardiovascular phenotype-specific manner. Interventional studies are needed to examine effects of exogenous T and its metabolites DHT and E2, on atherogenesis.

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.

Testosterone therapy and cardiovascular risk

Endogenous testosterone levels are inversely associated with cardiovascular risk in older men and men with cardiovascular disease. Current data on cardiovascular outcomes of testosterone therapy include only observational studies and adverse event monitoring in short-term trials that were not designed to measure cardiovascular outcomes. These studies have yielded conflicting results, and some have raised concerns that testosterone therapy may increase cardiovascular risk. A well-designed, adequately powered, prospective trial will ultimately be required to clarify whether testosterone therapy impacts cardiovascular outcomes. This review describes the findings and limitations of recent studies of cardiovascular risk in older men on testosterone therapy and discusses some of the mechanisms through which testosterone may modify cardiovascular risk.