Background: Left ventricular reverse remodeling (LVRR) determines clinical status and outcomes in dilated cardiomyopathy (DCM). The extent of myocardial fibrosis is connected to the systolic function of the heart. The recent discovery of the contribution of microRNAs (miRs) to the regulation of cardiac remodeling, LVRR and fibrosis warrants exploration.
Objectives: The aim of the study was to examine the predictive value of circulating and myocardial miR expression for LVRR in DCM.
Material and methods: Seventy consecutive DCM patients (age 48 ±12.1 years, 90% male, ejection fraction (EF) 24.4% ±7.4%) were included in the study. At baseline, all patients underwent clinical assessment, echocardiography, venous blood sampling, and right ventricular endomyocardial biopsy. Circulating and myocardial miRs (miR-21, -26, -29, -30, -133a, and -423) were measured with quantitative real-time polymerase chain reaction (qRT-PCR). LVRR was defined as an increase in EF ≥ 10%, accompanied by a decrease in left ventricle end-diastolic diameter (LVEDd) ≥10% or LVEDd ≤ 33 mm/m2 between baseline and 3-month follow-up.
Results: At the 3-month follow-up, 4 patients had died and 3 patients had incomplete data. The remaining patients were divided according to the presence of LVRR into LVRR-present (n = 32, 51%) and LVRR-absent (n = 31, 49%) groups. Out of all the circulating and tissue miRs under study, only myocardial expression of miR-133a significantly differed between the LVRR-present and LVRR-absent group (1.22 (0.47-1.90) vs 0.61 (0.25-0.99) ΔCq, respectively, p < 0.01). miR-133a was found to be a significant LVRR predictor in unadjusted (odds ratio (OR) = 2.81 (1.23-6.40), p < 0.05) and adjusted for duration of disease, left ventricle end-diastolic (LVED) volume (LVEDvol), hs-troponin-T, and NT-proBNP (OR = 5.20 (1.13-24.050, p < 0.05) models.
Conclusions: From all of the circulating and tissue miRs, only myocardial miR-133a showed increased expression in LVRR-present patients and was found an independent LVRR predictor. This indicates a link between miR-133 and cardiac remodeling in DCM.
Keywords: dilated cardiomyopathy; left ventricle reverse remodeling; microRNA.