Features of intestinal microbiota taxonomic composition and their relation with hormonal and immune status assessed in women with external genital endometriosis

Abstract

Aim: systemically assessed characteristics of intestinal microbiota taxonomic composition in relation to parameters of hormonal and immune status in patients with external genital endometriosis (EGE).Materials and Methods. The controlled cross-sectional study included 33 patients with EGE comprising main group, and 30 healthy women enrolled to control group. All women underwent assessment of hormonal status and cytokine expression levels in peripheral blood. Level of blood hormones estradiol (E2), follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL) was carried out using enzyme-linked immunosorbent and chemiluminescent assays. Expression levels of cytokines such as interleukin (IL) IL-6, IL-8, tumor necrosis factor alpha (TNF-α) were analyzed by an enzyme-linked immunosorbent assay. Taxonomic composition of intestinal microbiota at the level of phyla and genera was carried out by 16S ribosomal RNA gene sequencing. Microbial community a-diversity, the Chao1, ACE, and Sobs indices were used.Results. The concentration of blood E2 in main group was significantly higher compared to control group. Also, women with EGE had higher plasma concentrations for IL-6, IL-8, IL-17 and TNF-a compared to those in control group (p < 0.001). While analyzing bacterial community a-diversity in main group, Chao1 index was found to be significantly decreased. At the phylum level, the Firmicutes/Bacteroidetes ratio was increased in patients with EGE compared with that in control group. Among the 20 largest genera in patients with EGE, significant abundance was observed for Lachnospira, Blautia, Dorea, Streptococcus, Eubacterium hallii_group paralleled with significant decline in Bifidobacterium and Eubacterium eligens_group. A positive correlation was obtained between estrogen levels and the number of representatives from the genera Eubacterium hallii_group and Streptococcus, IL-8 and Streptococcus, TNF-α and Streptococcus and Lachnospira, as well as a negative correlation between TNF-α and Bifidobacterium.Conclusion. A relation between dysbiotic intestinal alterations and developing endometriosis was found. The identified correlations between altered taxonomic composition of the intestinal microflora and parameters of hormonal and immune status in patients with EGE suggest that intestinal microbiota is involved in pathophysiology of endometriosis.