Why is understanding the relationship of testosterone to cardiovascular risk so important? / 亚洲男科学杂志(英文版)

Epidemiological studies hint at a beneficial influence of endogenous circulating testosterone (T), or its metabolite dihydrotestosterone (DHT), such that men with lower concentrations of T or DHT appear to have poorer health outcomes including frailty, diabetes, cardiovascular disease, and mortality. Small interventional studies of T have shown favorable effects on surrogate outcome measures, but a large randomized controlled trial (RCT) with the prespecified outcome of cardiovascular events has not been performed and would be logistically demanding. In the absence of such a definitive RCT, there is a controversy about the cardiovascular risks of T-therapy fuelled by contradictory findings from retrospective analyses of insurance databases of men prescribed T. The US Testosterone Trials (T-Trials) are the largest published RCTs of T-therapy in older men with symptoms or signs of hypogonadism and circulating T <9.54 nmol l−1 at baseline. The T-Trials showed a modest benefit of T-therapy over a 12-month period on sexual function, a significant benefit in bone density and for anemia and neutral effect on cognition. The T-Trials cardiovascular sub-study was designed to determine the effects of T in these older men, and there was a statistically significant difference in the increase in noncalcified plaque volume in the T-treated group compared to placebo, but it is difficult to interpret these results due to differences in baseline coronary plaque burden (>50% difference) between the treatment and placebo arms of the subset involved. Therefore, there continues to be ongoing uncertainty over the effect of T-therapy on the cardiovascular system in men.

Endogenous testosterone and mortality risk / 亚洲男科学杂志(英文版)

In men, obesity and metabolic complications are associated with lower serum testosterone (T) and dihydrotestosterone (DHT) and an increased risk of, and mortality from, multiple chronic diseases in addition to cardiovascular disease (CVD). The causal interrelationships between these factors remain a matter of debate. In men with untreated congenital and lifelong forms of hypogonadotropic hypogonadism, there appears to be no increased risk. Men with Klinefelter's syndrome have an increased risk of various types of cancers, as well as CVD, which persist despite T therapy. In the absence of pathology of the hypothalamic-pituitary-gonadal axis, the effect of modest reductions in serum T in aging men is unclear. The prevalence of low serum T concentrations is high in men with cancer, renal disease, and respiratory disease and is likely to be an indicator of severity of systemic disease, not hypogonadism. Some population-based studies have found low serum T to be associated with a higher risk of deaths attributed to cancer, renal disease, and respiratory disease, while others have not. Although a meta-analysis of longitudinal studies has shown an association between low serum T and all-cause mortality, marked heterogeneity between studies limited a firm conclusion. Therefore, while a decrease in T particularly occurring later in life may be associated with an increase in all-cause and specific types of mortality in men, the differential effects, if any, of T and other sex steroids as compared to health and lifestyle factors are unknown at the current time.

Testosterone and its metabolites: differential associations with cardiovascular and cerebrovascular events in men / 亚洲男科学杂志(英文版)

As men grow older, circulating testosterone declines while the incidence of cardiovascular disease increases. Thus, the role of sex hormones as biomarkers, and possibly contributing factors to clinical manifestations of cardiovascular disease in the increasing demographic of aging men, has attracted considerable interest. This review focuses on observational studies of endogenous androgens, namely circulating testosterone and dihydrotestosterone, which have examined their associations with cardiovascular events such as myocardial infarction and stroke. Studies which have examined the associations of endogenous estrogens, namely circulating estradiol, with these outcomes are also discussed. In large prospective cohort studies of predominantly middle-aged and older men, lower circulating testosterone consistently predicts higher incidence of cardiovascular events. Of note, both lower circulating testosterone and lower dihydrotestosterone are associated with higher incidence of stroke. These associations are less apparent when myocardial infarction is considered as the outcome. Results for estradiol are inconsistent. Lower circulating testosterone has been shown to predict higher cardiovascular disease-related mortality, as has lower circulating dihydrotestosterone. It is possible that the relationship of circulating androgens to cardiovascular events or mortality outcomes may be U-shaped rather than linear, with an optimal range defining men at lowest risk. Epidemiological studies are observational in nature and do not prove causality. Associations observed in studies of endogenous androgens need not necessarily translate into similar effects of exogenous androgens. Rigorous randomized controlled trials are needed to clarify the effects of testosterone treatment on cardiovascular risk in men.

The association of 5-alpha reductase type 2 (SRD5A2) gene polymorphisms with prostate cancer in a Korean population

PURPOSE: Steroid 5-alpha reductase type 2 (SRD5A2) modifies testosterone to dihydrotestosterone (DHT) in the prostate. Single-nucleotide polymorphisms (SNPs) of the SRD5A2 gene might affect DHT. We sought to understand the relationship of SRD5A2 SNPs to prostate cancer in the Korean population. MATERIALS AND METHODS: Twenty-six common SNPs in the SRD5A2 gene were assessed in 272 prostate cancer cases and 173 controls. Single-locus analyses were conducted by using conditional logistic regression. Additionally, we performed a haplotype analysis for the SRD5A2 SNPs tested. RESULTS: Among the 20 SNPs and 4 haplotypes, there were no statistically significant results in the prostate cancer patients and the controls. In the logistic analysis of SRD5A2 polymorphisms with prostate-specific antigen (PSA) criteria, two SNPs (rs508562, rs11675297) and haplotype 1 displayed significant results (odds ratio [OR], 1.76; p=0.05; OR, 1.88-2.02; p=0.01-0.04; OR, 0.59; p=0.02, respectively). rs508562, rs11675297, rs2208532, and haplotype 1 (OR, 1.49; p=0.05; OR, 2.02; p=0.05; OR, 2.01; p=0.04; OR, 0.56-0.64, p=0.03-0.04, respectively) had significant associations with Gleason score. rs508562, rs11675297, and haplotype 1 (OR, 1.41-2.34; p=0.004-0.05; OR, 1.74-1.82; p=0.03-0.05; OR, 0.42-0.67; p=0.0005-0.03, respectively) were significantly associated with clinical stage. CONCLUSIONS: We conclude that there was no significant association between SRD5A2 SNPs and the risk of prostate cancer in the Korean population. However, we found that some SNPs and 1 haplotype influenced PSA level, Gleason score, and clinical stage.

Relationship between the climbing up and climbing down stairs domain scores on the FES-DMD, the score on the Vignos Scale, age and timed performance of functional activities in boys with Duchenne muscular dystrophy / Relação entre escore FES-DMD-subir e descer escada com escore Escala Vignos, idade e tempo de realização das atividades em meninos com Distrofia Muscular de Duchenne

BACKGROUND: Knowing the potential for and limitations of information generated using different evaluation instruments favors the development of more accurate functional diagnoses and therapeutic decision-making. OBJECTIVE: To investigate the relationship between the number of compensatory movements when climbing up and going down stairs, age, functional classification and time taken to perform a tested activity (TA) of going up and down stairs in boys with Duchenne muscular dystrophy (DMD). METHOD: A bank of movies featuring 30 boys with DMD performing functional activities was evaluated. Compensatory movements were assessed using the climbing up and going down stairs domain of the Functional Evaluation Scale for Duchenne Muscular Dystrophy (FES-DMD); age in years; functional classification using the Vignos Scale (VS), and TA using a timer. Statistical analyses were performed using the Spearman correlation test. RESULTS: There is a moderate relationship between the climbing up stairs domain of the FES-DMD and age (r=0.53, p=0.004) and strong relationships with VS (r=0.72, p=0.001) and TA for this task (r=0.83, p<0.001). There were weak relationships between the going down stairs domain of the FES-DMD-going down stairs with age (r=0.40, p=0.032), VS (r=0.65, p=0.002) and TA for this task (r=0.40, p=0.034). CONCLUSION: These findings indicate that the evaluation of compensatory movements used when climbing up stairs can provide more relevant information about the evolution of the disease, although the activity of going down stairs should be investigated, with the aim of enriching guidance and strengthening accident prevention. Data from the FES-DMD, age, VS and TA can be used in a complementary way to formulate functional diagnoses. Longitudinal studies and with broader age groups may supplement this information. .

CONTEXTUALIZAÇÃO: Conhecer as potencialidades e limitações das informações geradas por diferentes instrumentos de avaliação favorece o desenvolvimento mais preciso do diagnóstico funcional e da tomada de decisão terapêutica. OBJETIVO : Investigar a relação entre o número de movimentos compensatórios ao subir e descer escadas, idade, classificação funcional e tempo de realização de atividade (TA) em meninos com Distrofia Muscular de Duchenne (DMD). MÉTODO : Foi utilizado banco de filmes de 30 meninos com DMD realizando atividades funcionais. Os movimentos compensatórios foram avaliados pela Escala de Avaliação Funcional para Distrofia Muscular de Duchenne (FES-DMD), domínio subir e descer escada; a idade, mensurada em anos; a classificação funcional foi pesquisada pela Escala de Vignos (EV), e o TA foi cronometrado. Foi utilizado o teste de correlação de Spearman. RESULTADOS : Existe moderada relação entre a FES-DMD-subir escada e a idade (r=0,53, p=0,004) e forte relação com a EV (r=0,72, p=0,001) e TA dessa tarefa (r=0,83, p<0,001). Houve fraca relação entre a FES-DMD-descer escada e a idade (r=0,40, p=0,032), EV (r=0,65, p=0,002) e o TA dessa tarefa (r=0,40, p=0,034). CONCLUSÃO : Esses achados indicam que a avaliação da tarefa de subir escada pode trazer informações mais relevantes sobre a evolução da doença, embora a atividade de descer escada deva ser pesquisada visando à orientação e prevenção de acidentes. A utilização conjunta de dados provenientes da FES-DMD, da idade e do TA pode se complementar para formulação do diagnóstico funcional. Estudos longitudinais e com outras faixas etárias mais amplas podem complementar tal informação. .

Male contraception: expanding reproductive choice.

The development of steroid-based oral contraceptives had revolutionized the availability of contraceptive choice for women. In order to expand the contraceptive options for couples by developing an acceptable, safe and effective male contraceptive, scientists have been experimenting with various steroidal/non-steroidal regimens to suppress testicular sperm production. The non-availability of a long-acting androgen was a limiting factor in the development of a male contraceptive regimen since all currently tested anti-spermatogenic agents also concurrently decrease circulating testosterone levels. A combination regimen of long-acting progestogen and androgen would have advantage over an androgen-alone modality since the dose of androgen required would be much smaller in the combination regimen, thereby decreasing the adverse effects of high steroid load. The progestogen in the combination regimen would act as the primary anti-spermatogenic agent. Currently, a number of combination regimens using progestogen or GnRH analogues combined with androgen are undergoing trials. The side effects of long-term use of androgens and progestogens have also undergone evaluation in primate models and the results of these studies need to be kept in view, while considering steroidal regimens for contraceptive use in men. Efforts are also being made to popularize non-scalpel vasectomy and to develop condoms of greater acceptability. The development of contraceptive vaccines for men, using sperm surface epitopes not expressed in female reproductive tract as source, still requires considerable research efforts.