Stem cells in pediatric cardiology.

The ability to reprogram virtually any cell of human origin to behave like embryonic or pluripotent stem cells is a major breakthrough in stem cell biology. Human induced pluripotent stem cells (iPSC) provide a unique opportunity to study "disease in a dish" within a defined genetic and environmental background. Patient-derived iPSCs have been successfully used to model cardiomyopathies, rhythm disorders and vascular disorders. They also provide an exciting opportunity for drug discovery and drug repurposing for disorders with a known molecular basis including childhood onset heart disease, particularly cardiac genetic disorders. The review will discuss their use in drug discovery, efficacy and toxicity studies with emphasis on challenges in pediatric-focused drug discovery. Issues that will need to be addressed in the coming years include development of maturation protocols for iPSC-derived cardiac lineages, use of iPSCs to study not just cardiac but extra-cardiac phenotypes in the same patient, scaling up of stem cell platforms for high-throughput drug screens, translating drug testing results to clinical applications in the paradigm of personalized medicine, and improving both the efficiency and the safety of iPSC-derived lineages for future stem cell therapies.