Altered microRNA dynamics in acute coronary syndrome

INTRODUCTION: In the course of acute myocardial infarction (AMI) cardiomyocyte injury, activation and destruction of endothelial cells together with inflammation lead to miRNA expression alterations. AIM: To assess levels of circulating cardiac-specific (miR-1) and endothelial-specific (miR-126) miRNAs in the acute phase of AMI and after a follow-up period. MATERIAL AND METHODS: Seventeen AMI patients (mean age: 64.24 ±13.83 years, mean left ventricle ejection fraction (LVEF): 42.6 ±9.65%), treated with primary percutaneous coronary intervention within the first 12 h, had plasma miRNAs isolated (quantitative real-time PCR, Exiqon) on admission and after 19.2 ±5.9 weeks. Measurements were also performed in a control group of healthy volunteers matched for age and sex. RESULTS: Concentrations of both miRNAs were significantly higher in AMI patients as compared to healthy controls: miR-1: 5.93 (3.15–14.92) vs. 1.46 (0.06–2.96), p = 0.04; miR-126: 4.5 (3.11–7.64) vs. 0.54 (0.36–0.99), p = 0.00003, respectively. Levels of both miRNAs significantly decreased after the follow-up period: miR-1: 5.93 (3.15–14.92) vs. 1.34 (0.04–2.34), p = 0.002; miR-126: 4.5 (3.11–7.64) vs. 1.18 (0.49–1.68), p = 0.0005). Moreover, miR-1 correlated positively with maximal troponin I concentration (r = 0.59, p = 0.02) and negatively with LVEF (r = –0.76, p = 0.0004). CONCLUSIONS: In our study, miR-1 emerged as a marker of cardiomyocyte injury and loss of myocardial contractility, whereas dynamics of miR-126 concentration may reflect endothelial activation and damage in the most extreme stage of atherosclerosis, followed by angiogenesis in ischemic myocardium. However, to fully elucidate the role of miR-1 and miR-126 as biomarkers of AMI and future therapeutic targets, further research is required.