Heartbroken embryos heal

Abstract

An area of injured heart in zebrafish embryos repairs itself using cells from neighbouring areas. The regenerating cells seem to originate from an intermediate progenitor-cell population. See Letter p.497 Obstacles to the use of stem-cell therapy in heart failure patients include the difficulty of ensuring the differentiation of cardiac progenitor cells into functional ventricular cardiomyocytes, and the delivery and integration of differentiated cells into the patient's ventricular myocardium. Neil Chi and colleagues studied the ability of specific cardiac muscle cell types to differentiate into closely related but distinct cell types in embryonic zebrafish hearts. They find that differentiated atrial cardiomyocytes can transform into ventricular cardiomyocytes when the heart is injured and that the Notch signalling pathway induces the regeneration. This work identifies an endogenous population of cardiac cells as a potential source for cardiac ventricular regeneration.