Model organisms at the heart of regeneration.

Heart failure is a major cause of death worldwide owing to the inability of the adult human heart to regenerate after a heart attack. However, many vertebrate species are capable of complete cardiac regeneration following injury. In this Review, we discuss the various model organisms of cardiac regeneration, and outline what they have taught us thus far about the cellular and molecular responses essential for optimal cardiac repair. We compare across different species, highlighting evolutionarily conserved mechanisms of regeneration and demonstrating the importance of developmental gene expression programmes, plasticity of the heart and the pathophysiological environment for the regenerative response. Additionally, we discuss how the findings from these studies have led to improvements in cardiac repair in preclinical models such as adult mice and pigs, and discuss the potential to translate these findings into therapeutic approaches for human patients following myocardial infarction.