Although the genesis of the heart has been studied extensively in organisms including zebra fish, flies and mice, much less is known about what happens in the human heart, Chien said.
And while stem cells have been used to treat people after a heart attack, for instance, cells that are used are not from the heart and it's not yet clear how effective the approach really is.
Chien and his team used antibodies directed against islet progenitor cells in human fetal hearts to identify the presence of the cells. They then purified the cells, cloned them and tracked their journey from single stem cell to the three major lineages of heart cells -- smooth muscle, cardiomyocyte muscle and endothelial cells.
Chien said that he thought it would be "entirely unlikely" that scientists would be able to use these cells to "grow" a whole heart.
Instead, the key seems to be in identifying intermediary points and pathways by which the cells branch off into very specific types of cells and subsets of the major cells so they could be directed to these specific destinations.
"This sets up a system where we can now use scientific tools to rigorously identify the pathways that would drive the cell to become the cell of interest and not become the other cell of interest, and to test each rigorously in animal models as to which one would have a therapeutic effect," Chien said.
The researchers suspect that defects in the decisions of these stem cells could be responsible for various types of congenital heart disease.
But there is a danger in using embryonic stem cells in humans, according to Dr. Darwin J. Prockop, director of the Texas A&M Health Science Center College of Medicine Institute for Regenerative Medicine at Scott & White. And that is the potential for the cells to form tumors down the line.
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