A repair "kit" for the infarcted heart.

ABSTRACT

Transplanted, c-kit expressing marrow-derived progenitors can enhance the function of an infarcted heart, but the mechanism remains unclear. In this issue of Cell Stem Cell, Loffredo et al. (2011) provide evidence that hematopoietic precursors do not differentiate into new cardiomyocytes but, rather, stimulate production of new cardiomyocytes from endogenous progenitors.