Would male hormonal contraceptives affect cardiovascular risk?

A global grounded theory exploration of investigators' perspectives on male hormonal contraceptive development and acceptability

While best practices have been proposed on how to engage men in family planning (FP), the limited options of male hormonal contraceptives (MHC) are a barrier to reaching men as clients of FP programs. The lack of alternative MHC is preventing the global health community from providing holistic reproductive healthcare. A qualitative grounded theory study was conducted in 2020 to explore MHC experts' perceptions around the development and theoretical acceptability of MHCs. Individual in-depth interviews were conducted with 15 key informants. The informants cited evidence that there is a demand for MHC. The inability to access this data by the pharmaceutical industry was acknowledged. Many informants expressed concern of the possibility for MHC to increase male power in a predominantly patriarchal world. To most informants, at least for the initial introduction of MHC, fertility sharing is something that will largely happen among couples alone rather than individually. There is proven demand among women and men for MHC, however industries may still be reluctant to invest. Effort is needed by the sexual and reproductive health and rights community to include male engagement in FP and to advocate for the development and use of MHC as a tool for women's empowerment.

Sex Differences in Adiposity and Cardiovascular Diseases

Body fat distribution is a well-established predictor of adverse medical outcomes, independent of overall adiposity. Studying body fat distribution sheds insights into the causes of obesity and provides valuable information about the development of various comorbidities. Compared to total adiposity, body fat distribution is more closely associated with risks of cardiovascular diseases. The present review specifically focuses on the sexual dimorphism in body fat distribution, the biological clues, as well as the genetic traits that are distinct from overall obesity. Understanding the sex determinations on body fat distribution and adiposity will aid in the improvement of the prevention and treatment of cardiovascular diseases (CVD).

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.

Comparison of metabolic effects of the progestational androgens dimethandrolone undecanoate and 11β-MNTDC in healthy men

BACKGROUND

Dimethandrolone (DMA) and 11β-methyl-19-nortestosterone (11β-MNT) are two novel compounds with both androgenic and progestational activity that are under investigation as potential male hormonal contraceptives. Their metabolic effects have never been compared in men.

OBJECTIVE

Assess for changes in insulin sensitivity and adiponectin and compare the metabolic effects of these two novel androgens.

MATERIALS/METHODS

In two clinical trials of DMA undecanoate (DMAU) and 11β-MNT dodecylcarbonate (11β-MNTDC), oral prodrugs of DMA and 11β-MNT, healthy men received drug, or placebo for 28 days. Insulin and adiponectin assays were performed on stored samples. Mixed model analyses were performed to compare the effects of the two drugs. Student's t test, or the non-parametric Kruskal-Wallis test as appropriate, was used to evaluate for an effect of active drug versus placebo.

RESULTS

Class effects were seen, with decrease in HDL-C and SHBG, and increase in weight and hematocrit, with no statistically significant differences between the two compounds. No changes in fasting glucose, fasting insulin, or HOMA-IR were seen with either compound. There was a slight decrease in adiponectin with DMAU that was not seen with 11β-MNTDC. An increase in LDL-C was seen with 11β-MNTDC but not with DMAU.

DISCUSSION

There were no significant changes in insulin resistance after 28 days of oral administration of these novel androgens despite a mild increase in weight. There may be subtle differences in their metabolic impacts that should be explored in future studies.

CONCLUSION

Changes in metabolic parameters should be carefully monitored when investigating androgenic compounds.

Conclusions about testosterone therapy and cardiovascular risk

In this issue of Asian Journal of Andrology (AJA), several experts have reviewed the latest data on the potential and known effects of endogenous and exogenous testosterone (T) on cardiovascular risk. In the review by Meyer and Wittert, low endogenous serum T appears to be associated with higher risk of cardiovascular disease and overall mortality in certain populations such as Klinefelter syndrome and older men, but not in men with congenital hypogonadotropic hypogonadism.1 Whether this association is causal or whether low serum testosterone is a marker of other risk factors for cardiovascular disease such as obesity, diabetes mellitus, or other systemic disease is unknown. In Yeap's review of the relationship between circulating endogenous testosterone and its major metabolites, dihydrotestosterone, and estradiol, he raises the provocative hypotheses that there might be differential effects on cardiovascular and cerebrovascular risk related to endogenous testosterone and dihydrotestosterone concentrations.2 Based on the same epidemiological studies, Yeap postulates that there might be a U-shaped curve for circulating endogenous androgen concentrations such that lower and higher concentrations might confer greater risk of cardiovascular events and all-cause mortality than midrange concentrations. Shores demonstrates in a carefully done review of studies of large prescription databases (including >200 000 men) that testosterone therapy is not associated with overall mortality, myocardial infarction, stroke, or deep venous thrombosis events.3

The future of male contraception: a fertile ground

The continued and rapid expansion of the Earth’s population mandates the need for safe and effective measures of contraception. While a plethora of options exist for women, methods of contraception for the male partner are limited to condoms and vasectomy. The sequela of this discrepancy has led to the family planning burden falling disproportionately on the female partner. For the past several decades, extensive research has been undertaken exploring the feasibility of hormonal male contraception. This proposed method of contraception has focused on suppressing spermatogenesis by exploiting the hypothalamic-pituitary-gonadal (HPG) axis. Beginning with proof of concept studies in the early nineties, administration of testosterone in healthy male subjects has been shown to be an efficacious method of inducing sterility. Owing to ethnic differences in spermatogenesis suppression and the comparatively low rate of azoospermia in Caucasian men with androgen-only regimens, investigators have explored the addition of progestins to further enhance the efficacy of hormonal contraception. Though studies have revealed promise with androgen-progestin regimens, the lack of long-term studies has precluded the development of a marketable product. Recently, more research has been directed towards identifying non-hormonal alternatives to male contraception. These non-hormonal options have ranged from the development of devices facilitating reversible occlusion of the vas deferens lumen to medications disrupting various pathways in the process of spermatogenesis. Underlying the development of hormonal and non-hormonal strategies is the shared enthusiasm men and women have towards these male directed methods. The willingness of couples to pursue these alternatives combined with the global need to reduce the psychological and socioeconomic implications of unintended pregnancy ensures that research will continue to bring this goal to fruition.