Circulating microRNA-126 &122 in patients with coronary artery disease: Correlation with small dense LDL

Background: Coronary artery disease (CAD) and stroke are major causes of cardiovascular diseases related deaths. Conventional risk factors cannot explain the changes in atherosclerosis. New and useful diagnostic markers are required. MicroRNAs are small, noncoding RNA that regulate the gene expression implicated in the pathogenesis of various cardiovascular diseases. Endothelial dysfunction is involved in the early event of the atherosclerosis process. Aims: The current study was designed to evaluate the vascular endothelium-enriched miRNAs would be altered in CAD patients. Methods: Circulating miR-126 & 122 levels were measured in serum from 78 CAD patients and 60 non CDA patients by qRT-PCR analysis. Results: MiR-122 was significantly down regulated in CAD patients (p = 0.001), however the level of miR-126 did not show any change (p = 0.507). Remarkably, the level of miR-126 was significantly decreased in patients with CAD and high small dense low density lipoprotein (sdLDL) level. The level of miR-126 was significantly increased when sdLDL was higher in patients with risk factors for CAD but did not have angiographically significant CAD. Conclusion:. In CAD patient's, miR-126 level was lowered compared to non CAD patients, however the difference was not significant (0.507). However we found a direct relationship between endothelium-enriched miR-126 and sdLDL in patients with or without CAD. Our finding suggests that miR-126 may have a potential role in sdLDL cholesterol metabolism. Mir-122 plays a role in cholesterol biosynthesis and deteriorates the cardiovascular system through the process of inflammation, apoptosis, oxidative stress and ECM deposition in a number of cardiovascular diseases.