The role of serum levels of microRNA-21 and matrix metalloproteinase-9 in patients with acute coronary syndrome

Acute coronary syndrome (ACS) is one of the leading causes of cardiovascular death. It seems that microRNA-21 and matrix metalloproteinase-9 implicated in the pathogenesis of cardiovascular diseases. The aim of this study was to investigate the role of circulating miR-21 and MMP-9 as biomarkers for ACS. Based on coronary angiography and electrocardiography results, 50 patients with ACS and 50 patients with stable coronary artery disease (stable CAD) were enrolled in this study. Samples were collected from patients and stored at −80 °C. Serum miR-21 gene expression was measured by quantitative real-time PCR method. Serum total MMP-9 was measured by enzyme-linked immunosorbent assay kit. Also, the activity of MMP-9 was measured by gelatin zymography. Patients with ACS had a significantly higher miR-21 level compared to the stable CAD (log2-ΔCt\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\log \, 2^{{ - \Delta C_{\text{t}} }}$$\end{document} = 0.88 ± 0.06 and 0.31 ± 0.08 respectively, P < 0.001). At the same time, the serum levels and activity of MMP-9 were significantly higher in ACS patients compared to those with stable CAD (324.01 ± 17.57 and 204.6 ± 12.39 ng/mL, P < 0.001, and 2524.5 ± 131.3 and 1280.8 ± 19.6 units, P < 0.001, respectively). miR-21 expression levels were correlated positively with MMP-9, hs-CRP, and age and negatively with HDL-cholesterol (r = 0.33, P < 0.001, r = 0.22, P < 0.031, r = 0.26, P < 0.008, r = −0.32, P < 0.001, respectively). We concluded that increased serum expression of miR-21 and higher serum activity of MMP-9 may be useful indicators for ACS. However, we suggest further studies to be performed.