Role of Branched-Chain Amino Acids in Metabolic Changes of Polycystic Ovary Syndrome

ABSTRACT Importance Polycystic ovary syndrome (PCOS) is a common endocrine syndrome with multiple causes and polymorphic clinical manifestations, which is one of the important causes of menstrual disorders in women of childbearing age. It has been found that branched-chain amino acids (BCAAs), a class of essential amino acids that cannot be synthesized by the human body, play a significant role in the metabolic changes of PCOS, which may be involved in the pathogenesis of PCOS. Objective The purpose of this review is to summarize the relevance between BCAAs and metabolic abnormalities in PCOS and to explore their possible mechanisms. Evidence Acquisition The evidence is mainly obtained by reviewing the literature on PubMed related to PCOS, BCAAs, and related metabolic abnormalities and conducting summary analysis. Results The metabolism of BCAAs can affect the homeostasis of glucose metabolism, possibly by disrupting the balance of gut microbiota, activating mTORC1 targets, producing mitochondrial toxic metabolites, and increasing the expression of proinflammatory genes. The correlation between obesity and BCAAs in PCOS patients may be related to the gene expression of BCAA metabolism–related enzymes in adipose tissue. The association between BCAA metabolic changes and nonalcoholic fatty liver disease in PCOS patients has not been fully clarified, which may be related to the lipid accumulation caused by BCAAs. At present, it is believed that hyperandrogenism in patients with PCOS is not related to BCAAs. However, through the study of changes in BCAA metabolism in prostate cancer caused by hyperandrogenism, we speculate that the relationship between BCAAs and hyperandrogenism may be mediated by mTORC1 and amino acid transporters. Conclusions and Relevance Review of prior articles reveals that BCAAs may be related to insulin resistance, obesity, nonalcoholic fatty liver, and hyperandrogenism in PCOS patients, and its mechanisms are complex, diverse, and interrelated. This review also discussed the mechanism of BCAAs and these metabolic disorders in non-PCOS patients, which may provide some help for future research. Target Audience Obstetricians and gynecologists, family physicians Learning Objectives After completing this activity, the learner will be better able to discuss the relationship between BCAAs and different metabolic characteristics of PCOS and its possible mechanism; describe the close relationship between BCCAs and insulin resistance in patients with PCOS and explore various possible mechanisms between them; and explain the relationship between obesity and BCAAs and the correlation between BCCAs and nonalcoholic fatty liver disease and hyperandrogenism in patients with PCOS.