OBJECTIVETo study the expression difference in MicroRNA-21 (miRNA-21) levels of the plasma between the patients with coronary heart disease and the subjects without coronary artery lesions, and its clinical significance.

METHODSPlasma was obtained from the patients with coronary heart disease(trial group,56 cases) and the subjects without coronary artery lesions(control group, 10 cases), patients with coronary disease were divided into angina(AP, 39 cases) and acute myocardial infarction(AMI, 17 cases)subgroup, the contents of miRNA-21 were detected using qRT-PCR method, and the differential expression of miRNA-21 in each group was analyzed. The levels of creatine kinase isoenzyme (CK-MB), high sensitive troponin I(cTnI), B type natriuretic peptide urea (BNP), Gensini, left ventricular ejection fraction (LVEF), integral value of coronary left ventricular end diastole diameter (LV) and homocysteine (HCY) were determined and the correlation between miRNA-21 and these clinical indexes was analyzed.

RESULTSCompared with control group, there was a significant difference in expression of miRNA-21 in patients with angina and AMI (P < 0.05), and miRNA-21 expression in AMI group was much higher than that in AP group. There was statistical significance in CK, CK-MB, cTnI, Genisis integral comparison between AMI group and control group (P < 0.05). The correlation analysis showed that there was a positive correlation between expression of CK, CK-MB, cTnI and the level of circulating miRNA-21 in patients with acute myocardial infarction. And there was a negative correlation between BNP, Gensini integral, LVEF value of coronary artery, LV and circulating miRNA-21.

CONCLUSIONmiRNA-21 was significantly elevated in acute myocardial infarction subgroup than the control group. The level of miRNA-21 associates with the degree of coronary artery stenosis, and might be a potential marker for the diagnosis of acute myocardial infarction. miRNA-21 may play an important role in protecting myocardium from ischemia/reperfusion injury.