During birth, new blood vessels form around the heart to support its future growth. These new blood vessels were assumed to originate from ventricular endocardial cells. Now, a study by  Bin Zhou, M.D., Ph.D., and colleagues, published online on September 8 in Nature Cell Biology, has identified coronary endothelial cells as the true source of the new vessels.

The researchers used a special technique to generate two mouse models in which ventricular endocardial cells and coronary endothelial cells can be visualized separately as heart blood vessels form around the time of birth. The researchers found that cells of the embryonic coronary plexus (a pre-existing branching network of blood vessels) produce the angiogenic signaling factors VEGFR3 and DLL4, which in turn generate new coronary vessels in newborns. The same plexus cells and signaling factors were also found to promote the revascularization of the injured newborn heart, suggesting cell-based therapies could potentially treat heart attacks.

Dr. Zhou is professor of genetics, of pediatrics, and of medicine at Einstein.