Circulating microRNA-126 in patients with ischemic heart disease with type 2 diabetes mellitus and its relationship with glucometabolic disorders

The aim of the study was to investigate circulating microRNA-126-3p levels and its relationships with glucometabolic indices in patients with ischemic heart disease (IHD) and type 2 diabetes mellitus (Т2DM). Materials and methods. The study included 68 patients with stable coronary artery disease (CAD) and T2DM, 25 CAD patients without diabetes and 18 healthy individuals as a control. MiRNA126-3p was determined in blood plasma by real time polymerase chain reaction. Small nuclear RNA U6 was used as an endogenous control. Results. Circulating miRNA-126-3p levels in CAD patients both with T2DM (50.32 [19.54; 93.82]) and without diabetes (109.46 [49.52; 211.11]) were higher than in the controls (17.95 [13.74; 35.01]) (P = 0.018 and P < 0.001). But in patients with T2DM, miRNA126-3p level was decreased in comparison with patients without diabetes (P < 0.001). In patients with T2DM, miRNA-126-3p displayed a significant negative correlation with blood glucose level (R = -0.259, P = 0.037) and was correlated negatively with glycosylated hemoglobin (R = -0.246, Р = 0.056) and insulin resistance index HOMA-IR (R = -0.229, P = 0.082) reaching boundary level of statistical significance. In diabetic patients, lower miRNA-126-3p level (the 1st tertile) was associated with a significant increase in blood glucose level and HOMA-IR in comparison with the 3rd tertile (P = 0.011 and P = 0.041). According to the ROC-analysis, the decrease in miRNA-126-3p levels was significantly associated with the presence of T2DM in patients with САD: AUC was 0.734 (95 % CI: 0.631–0.822, P < 0.001). Conclusions. Circulating miRNA-126-3p levels in CAD patients both with and without T2DM were increased compared to the controls, possibly due to compensatory mechanisms. However, in patients with T2DM, miRNA-126-3p expression was significantly lower than in patients without T2DM. The lowest miRNA-126-3p level in CAD patients with T2DM was associated with the significant elevation of blood glucose level and the increase in insulin resistance. MiRNA-126-3p may serve as potential biomarker for predicting and early diagnosis of T2DM in patients with CAD.