February 1, 2013

Cell source of heart’s blood vessels

An unexpected group of cells generates the coronary arteries and may be useful for regeneration therapies following injury to the heart.

(Wellcome Images)

Understanding the origins and development of coronary arteries – the blood vessels that supply the heart with oxygen – could point to new strategies for treating coronary artery disease.

H. Scott Baldwin, M.D., Katrina Overall McDonald Chair in Pediatrics, Bin Zhou, M.D., Ph.D., and colleagues have discovered that endocardial cells that line the developing ventricles in the heart generate the endothelium (the inner layer) of coronary arteries. The studies disprove the current dogma that coronary arteries are derived from the epicardium (the heart’s outer layer) or from endothelial cells outside the heart.

The investigators used cell fate mapping, dye tracking, live imaging and tissue transplantation to demonstrate that ventricular endocardial cells can form new blood vessels. They showed that this process depends on signaling by VEGF (vascular endothelial growth factor) from the myocardium – the central heart layer where the coronary vessels form – to the endocardial cells. Endocardial cells did not generate coronary veins.

The studies, reported in the journal Cell, indicate that coronary arteries and veins have distinct origins and are formed by different mechanisms. The findings suggest that the endocardium might provide a resident population of cells that can be used in regeneration therapies to provide new coronary arteries, following injury to the heart.

This research was supported by grants from the National Institutes of Health (HL078881, HL100398, HL085345) and from the American Heart Association, and by a Turner-Hazinski Research Award.