Endocrine Abstracts

Introduction: Polycystic ovary syndrome (PCOS) is associated with an increased risk of insulin resistance. The involvement of microRNAs, small, non-coding molecules, in regulation of metabolic processes has been investigated. The role of miR-27a and miR-320 in regulation of glucose metabolism is documented. The aim of the study was to assess the level of circulating miR-27a and miR-320 in PCOS patients and to investigate its relationship with glucose metabolism.

Materials and methods: The studied group comprised 100 PCOS patients diagnosed with the Rotterdam criteria (age 24.3 ± 3.7 years, BMI 25.2 ± 5.3 kg/m²), divided into phenotypes (I–33 patients; II–24 patients; III–21 patients; IV–12 patients), and 88 healthy women as a control group (age 25.4 ± 4.3 years, BMI 23.4 ± 3.3 kg/m²). Anthropometric measurements, transvaginal ultrasound, assessment of sex hormones concentrations and oral glucose tolerance test (OGTT) were performed. Serum miR-27a and miR-320 levels were assessed with real-time polymerase chain reaction.

Results: The studied groups were similar in terms of age and BMI. Patients with PCOS presented higher glucose concentrations at 30 and 60 minutes of OGTT (P = 0.042; P = 0.023), higher insulin concentrations at 30, 60 and 120 minutes of OGTT (P = 0.049; P < 0.001; P = 0.013) and lower Matsuda index (P = 0.001) vs controls. Level of miR-27a was higher (P < 0.001) and miR-320 was lower (P < 0.001) in PCOS vs controls. Level of miR-27a was higher in phenotype I than in phenotype III (P = 0.021).

Fasting glucose concentration correlated with miR-27a (R = 0.32, P = 0.001) and miR-320 level (R = −0.28, P = 0.006) only in PCOS. In phenotype I, miR-27a level correlated with glucose at 0 and 120 minutes of OGTT (R = 0.45, P = 0.009; R = 0.36, P = 0.043), fasting insulin concentration (R = 0.44, P = 0.011), and Matsuda index (R = −0.40, P = 0.021). In phenotype II, miR-320 correlated with glucose at 0 and 60 minutes of OGTT (R = −0.41, P = 0.044; R = −0.47, P = 0.020). In phenotype III, miR-27a correlated with glucose concentration at 60 minutes of OGTT (R = 0.45, P = 0.038). In the subgroup of women with PCOS and impaired fasting glucose (IFG)/impaired glucose tolerance (IGT), we observed higher miR-27a and lower miR-320 level, comparing to PCOS patients with normal glucose tolerance (P = 0.003; P = 0.030). In patients with PCOS and IFG/IGT, miR-27a level correlated with fasting insulin concentration (R = 0.50, P = 0.029).

Conclusions: Serum levels of miR-27a and miR-320 are altered in PCOS patients and may be linked with impaired glucose metabolism. The association of miR-27a and miR-320 with insulin sensitivity seems to be more pronounced in phenotype I. Circulating miR-27a and miR-320 could serve as potential biomarkers of glucose metabolism disturbances in PCOS.