Micro-RNAs as promising biomarkers in cardiac diseases

miRNAs are endogenous, small (21-22 nucleotides), single-stranded, non-coding RNAs recently discovered (1). miRNAs complexed with Ago proteins (RISC complex) regulate gene expression by binding to reverse complementary sequences in their target mRNAs leading to mRNA degradation and/or repression of protein translation (2). Circulating miRNAs can be detected in serum or plasma and have been proposed as potential biomarkers for cardiovascular diseases, with high sensitivity (3).