The Role of MicroRNA in the Pathophysiology and Diagnosis of Viral Myocarditis.

Myocarditis is a non-ischemic condition with a heterogeneous etiology, clinical course and prognosis. The most common etiology of myocarditis are viral infections, whereas the most severe complications are acute and chronic heart failure and sudden cardiac death. The heterogeneous clinical course of the disease, as well as the availability and costs of diagnostic tools such as cardiac magnetic resonance and endomyocardial biopsy, hinder the diagnosis of myocarditis and its underlying cause. Non-coding RNAs such as micro-RNAs (miRNAs; miR) have been shown to be involved in the disease's pathophysiology; however, their potential in disease diagnosis and treatment should also be considered. Non-coding RNAs are RNAs that are not translated into proteins, and they have the ability to regulate several intracellular pathways. MiRNAs regulate gene expression by binding with their targets and inhibiting protein synthesis by interfering with the translation of coding genes or causing the degradation of messenger RNA. Several miRNAs, such as miR-1, -133, -21, -15, -98, -126, -155, -148, -203, -208, -221, -222, -203 and -590, have been shown to be involved in the pathophysiology of viral myocarditis (VMC), and some of them have been shown to have diagnostic abilities. This article summarizes the available data on miRNAs and their associations with VMC.