Introduction: MicroRNAs (miRNA) are a novel class of small noncoding single-stranded RNA molecules 1824 nucleotides long that regulate gene expression at the post-transcriptional level. There is increasing evidence of their importance in polycystic ovary syndrome (PCOS), with their differential expression depending on obesity. There is recent evidence that miRNA-93 and mi-RNA-223 may have a role to play in the modulation of insulin resistance, through GLUT4 modulation in adipose tissue that is inherent in this condition.
Objective: To determine if miRNA-93 and miRNA-223 are differentially expressed in the circulation of women with PCOS compared to age matched women without PCOS and to correlate these miRNAs to the metabolic indices found in PCOS.
Design: A casecontrol study comparing women with PCOS (n=25) to age (32.8±7.7 years vs 32.1±9.0 years) and weight (76.0±18.8 kg vs 77.4±16.3 kg) matched controls (n=24) without PCOS. miRNA-93 and miRNA-223 were determined by total RNA RT.
Results: Women with PCOS had significantly higher insulin, HOMA-β and testosterone levels compared to control subjects. Both miRNA-93 and miRNA-223 were significantly increased relative to the control group (P<0.016 and P<0.019 respectively). In both the control group and the PCOS group there was no correlation of either miRNA-93 or miRNA-223 with any of the parameters including insulin, HOMA-IR, HOMA-β, or testosterone levels. The area under the receiver operator characteristic (ROC) curve (AUC) for miR-223 and miR-93 was 0.66 and 0.72 respectively, suggesting miR-93 is a more efficient biomarker than miR-223 for the diagnosis of PCOS. The combination of the two miRNAs together, tested using multiple logistic regression analysis, did not improve the diagnostic potential of miR-93 alone (AIC miR-93+miR-223, 64.868 and AIC miR-93, 63.51).
Conclusions: Circulating miRNA-93 and miRNA-223 were higher in women with PCOS compared to age and weight matched controls independent of insulin resistance and testosterone levels, and miR-93 may represent a novel diagnostic biomarker for PCOS.