Sex, Microbes, and Polycystic Ovary Syndrome

Recent studies have shown that sex and sex steroids influence the composition of the gut microbiome. These studies also indicate that steroid regulation of the gut microbiome may play a role in pathological situations of hormonal excess, such as PCOS. Indeed, studies demonstrated that PCOS is associated with decreased alpha diversity and changes in specific Bacteroidetes and Firmicutes, previously associated with metabolic dysregulation. These studies suggest that androgens may regulate the gut microbiome in females and that hyperandrogenism may be linked with a gut ‘dysbiosis’ in PCOS. Future mechanistic studies will be required to elucidate how sex steroids regulate the composition and function of the gut microbial community and what the consequences of this regulation are for the host. 16S rRNA gene sequencing studies revealed that sex influences the taxonomic composition of gut bacteria in humans and rodents. The idea that sex-dependent differences in gut microbes are driven by sex steroid levels is supported by studies demonstrating that the gut microbiome diverges after puberty and that gonadectomy results in an altered gut microbiome. Recent studies demonstrated that changes in the gut microbiome are linked with androgen excess in women with PCOS and in female rodent models of the disorder. Studies reported that PCOS was associated with decreased alpha diversity and changes in the relative abundance of specific bacteria from the Bacteroidaceae, Clostridiaceae, Erysipelotrichidae, Lachnospiraceae, Lactobacillaceae, Porphyromonadaceae, Prevotellaceae, Ruminococcaceae, and S24-7 families previously linked with metabolic dysregulation.