Master stem cell capable of producing new heart tissue

Researchers in the United States believe they have discovered a "master" embryonic cardiac stem cell.

A team from the Massachusetts General Hospital (MGH) Cardiovascular Research Center say the stem cell is capable of producing all three types of cardiac tissue.

The researchers led by Dr. Kenneth R. Chien, Professor of Basic Science at Harvard Medical School, identified these progenitor cells in mice and by cloning single cells from embryonic stem cells, have shown that the cloned cells can differentiate into cardiac muscle, smooth muscle or endothelial or "pacemaker" cells.

Dr. Chien says these cells offer new prospects for drug discovery and genetically based models of human disease and also offer a new development for cardiac research.

The researchers say the cardiac stem cells that are responsible for forming the diverse cell types of the heart, could be good candidates for cardiac muscle regeneration studies, without the risk attached to using other cell types.

Experts say the stem cells have the potential to repair hearts by growing new cardiac tissue from them.

The human heart is composed of a variety of cell types, but Dr. Chien says until now it was not clear whether the different types of cells were due to the presence of a master cell which decided what it would be.

Chien's team found that there is a common origin for the three major cell types in the heart and each single cell is able to make that decision, but can also be cloned to develop into the three different cell types.

Dr. Chien says the discovery may be the first step in using embryonic stem cells for generating specific tissues.

Chien says embryonic stem cells offer this potential because the cells used are the ones that actually form the heart, as opposed to adult stem cells.

Experts say however that such applications in human patients are still a long way off, however.

The findings are published online Nov. 22 in the journal Cell.