Researchers in the United States have discovered a new group of stem cells that can give rise to heart muscle cells, known as cardiomyocytes, according to a study published Sunday.
The stem cells are located in the outermost layer of the heart and could one day play a critical role in regenerating injured heart tissue, the researchers say."In heart failure, you lose cardiomyocytes, so the only way to reverse heart failure is to make more of these cells," said William Pu, the study's lead researcher and a pediatric cardiologist at Children's Hospital in Boston, Massachusetts.
The new findings come on the heels of two earlier breakthroughs.
In 2006 scientists identified another cardiac stem cell -- marked by the expression of a gene called Nkx2-5 -- with the potential to become either heart muscle or cells lining blood vessels in the organ's left-sided chambers.
Gene expression is the process by which information encoded in the DNA of a particular gene is transformed into a protein or RNA, which plays a key role in protein synthesis.
In parallel, other US researchers discovered a related progenitor heart cell -- so-called because of its capacity to generate different types of tissue -- that produces the same cell types in the right-sided heart chambers.
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The results were independently verified by another team of scientists at the University of California in San Diego, whose research was published in the same issue of Nature.
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"If you are going to regenerate tissue, you need to regenerate the whole tissue, not just the cardiomyocytes," Pu said in a statement.
The discovery of the new stem cells was an accident. In order to study the role a different gene in the epicardium, the researchers labeled cells in live mouse embryos with red fluorescent protein.
"Unexpectedly, we saw that these epicardial cells were becoming cardiomycytes -- it was a lucky observation," said Pu.
The next challenge, he added, is trying to figure out how a progenitor stem cell decides to become a certain type of functioning cell within the heart, and then how to develop methods to trick the stem cells into transforming into the desired tissue.
"We still don't know how we can manipulate these progenitors," he said.
Source-AFP
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