Helping to change scientists' thinking about how the heart is formed, researchers at Children's Hospital Boston have identified a type of stem cell that is the precursor to at least two main cell types that form the heart. This single cardiac progenitor cell gives rise to both myocardial cells, which form the beating muscle and electrically conductive tissue of the heart, and to the vascular smooth muscle cells that line the heart's blood vessels. This cell is responsible for the formation of the left-sided chambers of the heart, the first chambers to form in the embryo.
Working in parallel, a separate team at Massachusetts General Hospital discovered a related progenitor cell that gives rise to the right-sided heart chambers, forming myocardial cells, smooth muscle cells, and endothelial cells.
Since these different cell types were thought to have separate ancestors, the studies offer a new understanding of the development of the mammalian heart the earliest organ to develop, and the one most susceptible to congenital defects. They also bring researchers a step closer to being able to regenerate tissues to repair congenital heart defects in children and damage caused by heart attacks in adults.
The two laboratories are now trying to determine the relationship between the two types of progenitor cells discovered. Both papers will appear in the December 15 issue of the journal Cell, which was published online November 22.
The Children's team, led by senior investigator Stuart H. Orkin, MD, a Howard Hughes Medical Institute investigator, and Sean Wu, MD, PhD, the study's first author, first worked with mouse embryonic stem cells in culture. They allowed the cells to differentiate in a Petri dish, then isolated a relatively rare subtype of cell (just 1 percent of the cells in the dish) that were poised to begin developing along a cardiac pathway. The presence of these cardiac progenitors was indicated by a green fluorescent pr
Contact: Alissa Rooney
Children's Hospital Boston