Structural and functional profiles of the gut microbial community in polycystic ovary syndrome with insulin resistance (IR-PCOS): a pilot study

Polycystic ovary syndrome (PCOS) is a complex endocrine and metabolic disorder that affects 9–21% of reproductive-aged women. Affected women frequently display obesity, insulin resistance, and inflammation. Altered gut microbial community has been reported in PCOS and obese PCOS patients. However, the profile of the gut microbial community in insulin resistant PCOS (IR-PCOS) patients still remains unknown. In this study, next-generation sequencing based on the 16S rRNA gene was used to compare the gut microbial composition of women with IR-PCOS (n = 9, PCOS with insulin resistance), NIR-PCOS (n = 8, PCOS alone) and healthy controls (n = 8, HC). We assessed that the composition of the gut microbial communities in NIR-PCOS and IR-PCOS patients were significantly altered. The family Bacteroidaceae was prolific in the NIR-PCOS group and reached its highest level in the IR-PCOS group, while the Prevotellaceae dramatically decreased in PCOS patients, especially in the IR-PCOS group. Subsequent correlation analysis revealed that the increased clinical parameter levels, including insulin resistance, sex-hormones and inflammation, were positively associated with the abundance of Bacteroidaceae, but negatively associated with that of Prevotellaceae. In addition, IR-PCOS patients also displayed a significant difference in their amounts of Ruminococcaceae and Lachnospiraceae when compared to the NIR-PCOS group. Moreover, the functional prediction from PICRUSt revealed that 73 pathways are significantly changed in the gut microbial communities of PCOS patients. Specifically, 21 metabolism-associated pathways, including the steroid hormone biosynthesis and lipopolysaccharide biosynthesis pathways, are obviously changed in IR-PCOS when compared to NIR-PCOS and HC groups. Taking this into consideration, our present study suggests that the dysbiosis of gut microbial communities occurred most notably in IR-PCOS patients, and the difference in gut dysbiosis profile between the IR-PCOS and NIR-PCOS should be considered in clinical treatment for PCOS patients and future drugs development.