Review in Translational Cardiology: MicroRNAs and Myocardial Fibrosis in Aortic Valve Stenosis, a Deep Insight on Left Ventricular Remodeling

MicroRNAs (miRNAs) are a huge class of noncoding RNAs that regulate protein-encoding genes (degradation/inhibition of translation). miRNAs are nowadays recognized as regulators of biological processes underneath cardiovascular disorders including hypertrophy, ischemia, arrhythmias, and valvular disease. In particular, circulating miRNAs are promising biomarkers of pathology. This review gives an overview of studies in aortic valve stenosis (AS), exclusively considering myocardial remodeling processes. We searched through literature (till September 2016), all studies and reviews involving miRNAs and AS (myocardial compartment). Although at the beginning of a new era, clear evidences exist on the potential diagnostic and prognostic implementation of miRNAs in the clinical setting. In particular, for AS, miRNAs are modulators of myocardial remodeling and hypertrophy. In our experience, here presented in summary, the principal findings of our research were a confirm of the pathophysiological role in AS of miRNA-21, in particular, the interdependence between textural miRNA-21 and fibrogenic stimulus induced by an abnormal left ventricular pressure overload. Moreover, circulating miRNA-21 (biomarker) levels are able to reflect the presence of significant myocardial fibrosis (MF). Thus, the combined evaluation of miRNA-21, a marker of MF, and hypertrophy, together with advanced echocardiographic imaging (two-dimensional speckle tracking), could fulfill many existing gaps, renewing older guidelines paradigms, also allowing a better risk prognostic and diagnostic strategies.