Researchers at Children's Hospital Boston say they have pinpointed a new, previously unrecognized group of stem cells that give rise to cardiomyocytes; heart muscle cells. These stem cells, located in the surface of the heart, or epicardium, advance the hope of being able to regenerate injured heart tissue.
Previously, the Children's team found that a specific stem cell or progenitor, marked by expression of a gene called Nkx2-5, forms many components of the heart: heart muscle cells, vascular smooth muscle cells, and the endothelial cells lining blood vessels in the heart's left-sided chambers. The team at MGH found a related progenitor, marked by expression of the Isl1 gene, that produces these same cell-types in the right-sided heart chambers.
Now, researchers have shown that heart muscle cells can also be derived from a third type of cardiac progenitor, located within the epicardium and identifiable through its expression of a gene called Wt1.