Introduction: MicroRNA (miRNAs) are noncoding RNAs involved in the regulation of gene expression. Certain miRNAs, especially miRNA-21 (miR-21), may be involved in lipid metabolism.
Objectives: The aim of the study was to evaluate the association between plasma free circulating miR-21 levels and lipid fractions: total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), non-HDL-C, and triglycerides (TG), as well as their atherogenic profile expressed as the ratio of individual lipid fractions (TC:LDL-C, TC:non-HDL-C, TG:HDL-C, and HDL-C:LDL-C) in patients with acute coronary syndromes without persistent ST -segment elevation (NSTE ACS).
Patients and methods: The study group consisted of 34 patients diagnosed with NSTE ACS on admission to the emergency department. Plasma miRNA levels were determined by real-time polymerase chain reaction and the ΔΔCt method. Serum lipid fractions were assessed after a minimum of 12-hour fasting during the first day of hospitalization.
Results: MiR-21 levels showed a significant inverse correlation with TC (r = -0.5; P = 0.002), LDLC (r = -0.5; P = 0.001), and non-HDL-C (r = -0.6; P <0.001) levels. Moreover, they were inversely correlated with TC:HDL-Cratio (r = -0.6; P <0.001), LDL-C:HDL-Cratio (r = -0.6; P <0.001), TG:HDL-Cratio (r = -0.4; P = 0.037), and TC:non-HDLratio (r = 0.6; P <0.001). In a multivariate analysis, miR-21 levels (β = -0.41; P = 0.018) and the need for revascularization (β = 0.35; P = 0.027) were independent predictors of non-HDL-C levels.
Conclusions: Free circulating miR-21 levels inversely correlate with TC, LDL-C, and non-HDL-C and are an independent predictor of non-HDL-C levels in patients with NSTE ACS. Thus, the overexpression of miR-21 is associated with a less atherogenic lipid profile.