The following is a summary of “Sex Hormones, the Stool Microbiome, and Subclinical Atherosclerosis in Women With and Without HIV,” published in the February 2024 issue of Endocrinology by Peters, et al.

The cardioprotective effects of endogenous estrogens are of particular importance in women with HIV, who often experience reduced estrogen exposure and heightened cardiovascular disease risk. Although the gut microbiome is known to interact metabolically with sex hormones, its potential impact on cardiovascular risk remains poorly understood. For a study, researchers sought to investigate the possible interplay between sex hormones and the gut microbiome about cardiovascular risk. 

They assessed 197 postmenopausal women enrolled in the Women’s Interagency HIV Study. Serum levels of 15 sex hormones were measured, and the composition of the gut microbiome was assessed using stool samples. Additionally, carotid artery plaque presence was determined using B-mode ultrasound in a subset of participants (n = 134). Associations were examined between sex hormones and stool microbiome, sex hormones and plaque, and sex hormone-related stool microbiota and plaque while adjusting for potential confounding factors.

The median age of participants was 58 years, with the majority living with HIV (81%). They found that sex hormones, including estrogens, androgens, and adrenal precursors, were associated with the diversity and specific species of the stool microbiome, with similar patterns observed in women with and without HIV. Specifically, higher estrogen levels were linked to greater microbiome diversity and increased abundance of species from Alistipes, Collinsella, Erysipelotrichia, and Clostridia, as well as higher levels of microbial β-glucuronidase and aryl-sulfatase orthologs, which are involved in hormone metabolism. Moreover, several hormones were associated with reduced odds of carotid artery plaque, including dihydrotestosterone, 3α-diol-17G, estradiol, and estrone. Exploratory mediation analysis suggested that species related to estrone, particularly those from the Collinsella genus, may mediate the protective association of estrone with plaque formation.

In conclusion, serum sex hormones significantly predict stool microbiome diversity and composition. Furthermore, the findings suggested a potential role of the gut microbiome in mediating estrogen-related cardiovascular protection.

Reference: academic.oup.com/jcem/article-abstract/109/2/483/7255286