GSE172172
Endometrial Microbiota is More Diverse in Women with Endometriosis than Symptomatic Controls
Endometriosis is a chronic, estrogen-dependent gynecological condition that affects approximately 10% of women of reproductive age. The most widely accepted theory of the etiology of endometriosis includes the process of retrograde menstruation, where menstrual effluent travels up the Fallopian tubes, accesses the peritoneal cavity, and in some people is able to establish endometriotic lesions. Recent reports suggest the uterus is not devoid of bacteria, as was once believed. Thus, the refluxed menstrual effluent may also carry bacteria along with it, and this bacteria has been suggested to contribute to inflammation, and establishment and growth of endometriotic lesions. Here, we sought to compare and contrast the uterine bacteria (endometrial microbiota) in women with surgically confirmed presence or absence of endometriosis using next-generation 16S rRNA gene sequencing. We obtained an average of more than 9000 sequence reads per endometrial biopsy, and found that the endometrial microbiota of women with endometriosis was more diverse (greater Shannon Diversity Index and greater proportion of 'Other' taxa) than that of symptomatic controls (women with pelvic pain, but with surgically confirmed absence of endometriosis; diagnosed with other benign gynecological conditions at surgery). The difference in endometrial microbiotas was supported in unsupervised cluster analyses where some clustering of endometrial microbiota by disease status (endometriosis vs. controls) was observed. The bacterial taxa enriched in the endometrial microbiota of women with endometriosis belonged to the Actinobacteria phylum, Oxalobacteraceae and Streptococcaceae families, and Tepidimonas genus, while those enriched in the symptomatic controls (without endometriosis) belonged to the Burkholderiaceae family, and Ralstonia genus. Taken together, our findings suggest the endometrial microbiota is perturbed in people with endometriosis. Overall design: Endometrial bacterial profiles of people with and without endometriosis were generated by 16S rRNA gene sequencing using the Illumina MiSeq platform.