Background. MicroRNAs play a key role in regulating various functions of both healthy and damaged cells; however, their role in the development of cardiovascular diseases and bone mineral disorders in the population of dialysis patients remains poorly understood. There are also no studies comparing the profile of various miRNAs in patients on hemodialysis and peritoneal dialysis.
Objective. Evaluation of the associations between the blood serum miRNA-21, miRNA-126 and miRNA-210 levels and the adequacy of dialysis, left ventricular myocardium contractility (ejection fraction), and lipid metabolism in patients on renal replacement therapy (RRT) with hemodialysis and peritoneal dialysis.
Materials and methods. The study included 40 patients, of whom 18 received programmed hemodialysis (PHD) therapy, 28 - peritoneal dialysis (PD). The control group consisted of 28 healthy volunteers. In addition to routine examination methods, assessment of the adequacy of dialysis by Kt/V and echocardiography, all patients underwent the determination of the miRNA-21, miRNA-126 and miRNA-210 expression levels by the real-time polymerase chain reaction.
Results. A highly significant negative correlation between the miRNA-126 expression level and the dialysis adequacy indicator by Kt/V was revealed (rs = -0.687; P = 0.002). Both miRNA-21 and miRNA-126 had negative correlation with serum total cholesterol levels (rs = -0.409; P = 0.009 and rs = -0.414; P = 0.008, respectively). Low microRNA-21 levels were associated with higher low-density lipoprotein level (rs = -0.4; P = 0.01), while microRNA-126 negatively correlated with the high-density lipoprotein level (rs = -0.36; P = 0.024). An increase in the miRNA-21 and miRNA-126 expression levels was observed in patients with atrial fibrillation (P= 0.003). The miRNA-210 expression level negatively correlated with the value of the left ventricular ejection fraction (LVEF) measured by Simpson method according to echocardiography data (rs = -0.5; P = 0.01).
Conclusion. A negative association between the miRNA-126 expression level and indicators of dialysis adequacy in dialysis patients was found. Indicators of microRNA expression also reflect the state of lipid metabolism in dialysis patients. In particular, low microRNA-21 levels were associated with increased proatherogenic low-density lipoprotein levels. MicroRNA-21 and microRNA-126 directly correlated with the prevalence of atrial fibrillation, and microRNA-210 negatively correlated with the LVEF measured according to Simpson method.

Keywords: microRNA, chronic kidney disease, dialysis, bone mineral metabolism, cardiovascular complications