MicroRNAs as Diagnostic, Prognostic and Predictive Biomarkers of Cardiac Disease

Cardiac disease is a leading cause of morbidity and mortality worldwide and is likely to remain a major challenge into the 21st century because of population aging and global epidemic of obesity. Primary prevention is the most effective way to reduce the disease burden but has produced limited success due to challenges in its societal implementation and individual compliance. The alternative, complementary approach could be secondary prevention to slow the progress of disease in its earliest stages, and biomarkers can contribute to the success by improving risk stratification and also providing surrogate endpoints to enable more rapid performance of clinical studies to develop tailored treatment. MicroRNAs (miRs) are small, non-coding RNA molecules that play important regulatory roles in gene expression. MiRs are generally considered to act as intracellular mediators essential for normal cardiac function and their deregulated expression profiles have often been associated with cardiovascular diseases. Recent discoveries demonstrated that miRs circulate in a stable form through many body fluids including blood, opening the possibility that circulating miRs can serve as diagnostic, prognostic or predictive markers for a variety of cardiovascular diseases including acute myocardial infarction and heart failure. Given that each specified miR has its unique sets of target genes, development of miR biomarkers together with identification of the target mRNAs may have utility for pharmacological intervention. This review summarizes the literature on miRs as cardiac biomarkers, followed by a summary of recent patents that utilize miRs as diagnostic markers of heart disease.