Introduction to the series on microRNAs in the cardiovascular system.

Until recently, microRNAs (miRNAs) were considered to be relatively small players in biological systems by having a balancing function through moderate effects on gene expression levels. However, it has become appreciated that miRNAs are actually much more relevant during both development and disease, which is underscored by the attention they have been receiving. The goal of this thematic review series is to highlight current knowledge of miRNA function during cardiovascular development, their dysregulation under disease conditions and the disease modifying functions they have been shown to exert in the cardiovascular system. These reviews, in addition to discussing the recent advancements in using miRNAs as circulating biomarkers or therapeutic modalities, will hopefully be able to provide a strong basis for future research to further expand our insights into miRNA function in cardiovascular biology.