Right ventricular morphology and function is not related with microRNAs and fibrosis markers in dilated cardiomyopathy.

Background: The relationship between right ventricle (RV), extracellular matrix (ECM) fibrosis and fibrosis-linked, circulating microRNAs in dilated cardiomyopathy (DCM) is unknown. Aim: The aim of the study was to uncover the associations between serum markers of ECM metabolism and circulating microRNAs with RV morphological and functional parameters. Methods: The study population consisted of 70 consecutive DCM patients (ejection fraction 24.4 +/- +/- 7.4%). Based on detailed echocardiographic assessment - 15 patients had normal RV, whereas 55 patients had RV dilatation (RVD) and/or RV systolic dysfunction (RVSD). Procollagens type I and III carboxy- and amino-terminal peptides, osteopontin (OPN), TGF1-beta 1, connective tissue growth factor (CTGF), MMP-2, MMP-9 and TIMP-1 were measured in serum as well as expression of miR-21, miR-26, miR-29, miR-30 and miR-133a. All patients underwent endomyocardial biopsy. Results: Biopsy-proven fibrosis was evenly distributed in two groups. Serum levels of fibrosis markers did not differ between groups. OPN, CTGE MMP-2, and TIMP-1 correlated with RV parameters. Only miR-133 a was differently expressed in both groups. MIR-21, miR-26, miR-30, and miR-133a correlated with RV morphological but without functional parameters. Not a single marker of fibrosis was independently associated with RV. MIR-30 was associated with RV impairment in the logistic regression model adjusted for age, sex, body mass index, and disease duration; however, lost its significance in the more comprehensive model. Conclusions: Right ventricle structural and functional abnormalities are common in DCM. ECM fibrosis and serum markers are not associated with RV impairment. The prognostic value of studied rnicroRNAs on RV is limited in DCM.