Circulatory microRNA 23a and microRNA 23b and polycystic ovary syndrome (PCOS): the effects of body mass index and sex hormones in an Eastern Han Chinese population

Background: MicroRNAs (miRNAs) regulate the expression of genes involved in various cellular functions related to metabolism, inflammation, and reproduction. This study evaluated the effects of sex hormones and obesity on the expression of circulating miR-23a and miR-23b in women with polycystic ovary syndrome (PCOS) and healthy women. Methods: Serum sex hormones concentrations and body mass index (BMI) were measured in 18 women with PCOS and in 30 healthy women from the East China area and these measurements were correlated with serum miR-23a/b levels. The effect of miR-23a and miR-23b risk factors on occurrence of PCOS and predisposing factors of PCOS on these miRNA expressions were evaluated. Results: The expressions of miR-23a/b were significantly lower in the women with PCOS than the normal women, and the expression levels of miR-23a/b were positively correlated with each other in the normal women (p = 0.001) but not in the women with PCOS (p > 0.05). In the women with PCOS, miR-23a was positively correlated with BMI (p = 0.03). However, no correlations were found between the levels of miR-23a/b and the sex hormones in the normal and PCOS women. On the other hand, without considering the presence or absence of PCOS, increase in BMI had a positive effect on the levels of circulating miR-23b; while testosterone had negative effects on the levels of circulating miR-23a. Furthermore, the likelihood of women with PCOS decreased by 0.01-fold for every 1 fold increase of miR-23a expression. Conclusions: Both reduced levels and discordance between the expressions of miR-23a/b were observed in the women with PCOS and miR-23a/b were affected from testosterone and BMI, reversely. Therefore, miR-23a alteration in contrast with miR-23b is a better indicator for evaluation of PCOS than the miR-23b.