Sex Hormone Androgen Elevates Blood Pressure Through Gut Microbiota-TMAO Pathway

Hypertension is a leading risk factor for all-cause mortality worldwide, affecting ≈1.3 billion people. Imbalanced gut microbiota contributes to blood pressure elevation. We recently reported sex differences in the responses of gut microbiota to environmental stimuli, such as salt, with male gut microbiota being more vulnerable to induce high blood pressure than female microbiota. In this study, we investigated the mechanisms by which gut microbiota regulate blood pressure in a sex-dependent manner.

Antibiotic treatment, gonadectomy, sex hormone replenishment, and treatment with trimethylamine N-oxide or its blocker were performed in male and female spontaneously hypertensive rats.

We observed sex differences in gut microbiota composition and sex-specific blood pressure responses to antibiotic treatment in pubertal spontaneously hypertensive rats. In gonadectomized rats treated with sex hormones, we found that the male sex hormone dihydrotestosterone elevated blood pressure, reshaped gut microbiota, and increased levels of microbiota-derived metabolites, trimethylamine and trimethylamine N-oxide. The accumulation of trimethylamine N-oxide in plasma and the paraventricular nucleus of the hypothalamus was associated with inflammation and sympathetic activation.

These findings underscore the mechanistic role of dihydrotestosterone in gut microbiota-mediated sex-specific blood pressure regulation and suggest that targeting the gut microbiota-treatment with trimethylamine N-oxide pathway may provide new therapeutic strategies for male hypertension.