Objective: Emerging evidence has linked the gut microbiota with human metabolic diseases. This study is aimed at investigating the role of gut microbiota and the potential effect of gut microbiota modulation in polycystic ovary syndrome (PCOS).

Methods: We performed an observational study in a cohort of reproductive women with and without PCOS. Subjects with previous history of gastrointestinal surgery or diseases (such as inflammatory bowel disease), taking antibiotics within 3 months prior to the study were excluded. Diagnosis of PCOS was done according to Rotterdam criteria. A total of 78 women were finally included, information regarding their clinical history, symptoms, anthropometric measurements and laboratory data were collected. Fecal bacteria profiling was conducted using 16S rRNA sequencing method. Individuals with PCOS were then randomized to metformin or probiotics (containing Lactobacillus and Bifidobacterium) treatment for 3 months.

Results: We identified that women with PCOS had lower fecal bacteria gene counts, lower bacterial diversity and higher β diversity, indicating lower gene richness and a more heterogeneous gut microbiota community structure. In addition, serum lipid profiles (including total cholesterol, HDL-cholesterol), androgen levels and indexes of insulin resistance (HOMA-IR, Matsuda insulin sensitivity index) were closely correlated with Prevotellaceae, Ruminococcaceae and Lachnospiraceae, which are dominant bacteria in energy metabolism. Furthermore, treating PCOS patients with metformin or probiotics both improved their menstruation cycles, decreased androgen levels and alleviated insulin resistance. Meanwhile, there were significant correlations between changes in metabolic parameters and shifted bacterial populations.

Conclusion: Our findings identify the gut microbiota dysbiosis in PCOS and suggest that it may be possible to intervene in PCOS by targeting the gut microbiota.


B. Zhang: None. S. Shen: None. Y. Bi: None. D. Zhu: None.

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