DURHAM, N.C. Just a handful of cells in the embryo are all that's needed to form the outer layer of pumping heart muscle in an adult zebrafish.
Researchers at Duke University Medical Center used zebrafish embryos and careful employment of a new technique that allows for up to 90 color labels on different cells to track individual cells and cell lines as the heart formed.
The scientists were surprised by how few cells went into making a critical organ structure and they suspect that other organs may form in a similar fashion, said Kenneth Poss, Ph.D., professor in the Duke Department of Cell Biology and Howard Hughes Medical Institute.
The study appears online in Nature on April 25.
"The most surprising aspect of this work is that a very small number of cardiomyocytes (heart muscle cells) in the growing animal can give rise to the thousands of cardiomyocytes that form the wall of the cardiac ventricle," said Vikas Gupta, lead author, who is in the Duke Medical Scientist Training Program for M.D. and Ph.D. degrees.
Gupta found that about eight single cells contributed to forming the major type of heart muscle in the wall of the zebrafish heart -- and just one or two cells could create anywhere from 30 to 70 percent of the entire ventricular surface.
"Clonal dominance like this is a property of some types of stem cells, and it's a new concept in how to form an organ during development," Poss said.
Another surprise was the way the patches of cloned cells formed muscle.
"It was completely unexpected," Gupta said. "I thought the wall would simply thicken in place, but instead there was a network of cells that enveloped the ventricle in a wave. It was as if a cell at your shoulder grew a thin layer of new cells down your arm surface."
Gupta said this opens an area for investigation to see whether or not a process like this repeats in the hearts of mammals, and perhaps i
|Contact: Mary Jane Gore|
Duke University Medical Center