MicroRNAs: pleiotropic players in congenital heart disease and regeneration.

Congenital heart disease (CHD) is the leading cause of infant death, affecting approximately 4-14 live births per 1,000. Although surgical techniques and interventions have improved significantly, a large number of infants still face poor clinical outcomes. MicroRNAs (miRs) are known to coordinately regulate cardiac development and stimulate pathological processes in the heart, including fibrosis or hypertrophy and impair angiogenesis. Dysregulation of these regulators could therefore contribute (I) to the initial development of CHD and (II) at least partially to the observed clinical outcomes of many CHD patients by stimulating the aforementioned pathways. Thus, miRs may exhibit great potential as therapeutic targets in regenerative medicine. In this review we provide an overview of miR function and elucidate their role in selected CHDs, including hypoplastic left heart syndrome (HLHS), tetralogy of Fallot (TOF), ventricular septal defects (VSDs) and Holt-Oram syndrome (HOS). We then bridge this knowledge to the potential usefulness of miRs and/or their targets in therapeutic strategies for regenerative purposes in CHDs.