Early overexpression of miR-499 in non-ST elevation acute coronary syndromes predicts long-term risk of major adverse cardiac events
Abstract Background Some studies reported utility of microRNAs in myocardial infarction diagnostic process, whereas their prognostic remains unclear. Aim To evaluate the prognostic value of five circulating miRs (miR-1, miR-21, miR-133a, miR-208, miR-499) levels for predicting major adverse cardiac events (MACE), including death, nonfatal myocardial infarction (MI) or cardiovascular rehospitalization (reh.) in patients with NSTE-ACS. Material and methods In our prospective, single-center observational study we recruited patients (pts) with NSTE-ACS with symptoms onset <24 hours before the hospital admission and age, gender-matched patients with stable coronary artery disease (SCAD) as controls. Blood was sampled twice (at admission and 4h after in NSTE-ACS and once in SCAD). Relative expression of miRs were calculated using the ΔΔCt method after normalization to the cel-miR-39 spiked-in control. The mean value of miRs relative expression from two time samples in NSTE-ACS pts were used for further analysis. Subjects were categorized according to mean miRs expression at hospital admission into two group (≤ or > median level of miRs). Results 103 NSTE-ACS pts (median age 67 years, 68% male) were included in this study. During median 1569 (IQR 935–1842) days of follow-up the primary endpoint (MACE) occurred in 66 (64.1%) pts: 18 pts (18.7%) died, 30 pts (20%) presented with MI and 85 pts (56.7%) were readmitted. In a Cox proportional-hazards regression model miR-499 expression > median level (HR=1.82, 95% CI 1.07–3.09) and high-sensitivity troponin T level (HR=1.24, 95% CI 1.05–1.46) were independent predictors of MACE in long term observation, even after adjustment for other covariates (including other miRNAs). Incidence of MI [34% vs 10%, HR=4.1 (2.0–8.5)], rehospitalization for cardiovascular reasons [67% vs 49%, HR=2.1 (1.3–3.3)] and MACE [76% vs 55%, HR=2.2 (1.5–3.5)] was significantly higher in pts with elevated (> median) miR-499 levels at hospital admission. None of analyzed miRNAs was related to long-term mortality, whereas the left ventricular ejection fraction (EF) has been identified as the only one survival predictor (HR=0.95, 95% CI 0.92–0.98). Conclusions Elevated miR-499 levels independently of high sensitivity troponin T levels in early phase of NSTE-ACS are related to increased rate of MACE in 4-year follow-up. Figure 1. miR499 and MACE Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): This study was supported by the Polish Ministry of Science and Higher Education “Diamond Grant” program.