Discovered! - Stem Cells In Heart’s Surface: New Vistas For Regenerative Surgery

In a research finding which might move on to become one of the breakthrough discoveries in heart tissue regenerative surgeries, researchers have found stem cells located in the heart’s surface, which are actually responsible for the development of cardiomyocytes – the heart muscle cells.

Researchers at Children's Hospital Boston are very excited about their find, as this particular type of previously unnoticed stem cells, is expected to pave the way for better treating patients of heart failures.

"There's a lot of interest in finding places to obtain new cardiomyocytes, because in heart failure, you lose cardiomyocytes, so the only way to reverse heart failure is to make more of these cells," said William Pu, M.D., a pediatric cardiologist at Children's Hospital and the study's senior investigator.

The researchers earlier found that stem cells marked by the expression of the gene Nkx2-5, helps form the heart muscle cells, the vasculardefine smooth muscle cells and the endothelial cells lining the blood vessels in the left sided chambers of the heart.

They then further discovered that a related type of stem cells marked by the expression of the gene IsI1 produce the same kind of cells in the right sided chambers of the heart.

Finally, quite to their surprise they discovered that besides the above two, heart muscle cells could also develop from a third type of cardiacdefine stem cells, marked by the expression of the gene Wt1. these cells were located within the epicardiumdefine.

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.

Bin Zhou, the study's first author “could not believe it” initially, that the stem cells found on the heart’s surface, called the epicardial cells, which have been known as ones that make the smooth muscle and endothelial cells during coronary vessel formation, are actually capable of developing into cardiomyocytes also.

Pu and Zhou discovered this fact when they tagged the Wt-1 expressing epicardial cells with a fluorescent red protein. They then allowed cell differentiation. The result showed cardiomyocytes carrying the same red marker along with another cell having different origins. Hence, proving the researchers’ findings to be correct.

Similar independent research was later done by researchers from the University of California, San Diego. They used a different genetic marker, Tbx18 and obtained the same results proving that cardiomyocytes can be derived from the epicardium.