New Hope for Stem Cells Repairing Hearts
Rat study finds engineered ones restore function
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MONDAY, Aug. 11, 2003 (HealthDayNews) -- A new study indicates genetically engineered stem cells can repair damaged heart muscle and restore normal heart function after a heart attack.
"There has been a lot of interest in whether stem cells can be used as a way to repair the heart after a heart attack, and there is data that suggests that stem cells can work," says Dr. Victor Dzau, chief of medicine at Brigham and Women's Hospital in Boston.
However, many stem cells die after being transplanted into heart tissue and their potential benefit is lost. As a result, "there are not enough cells to do the regeneration and repair of heart tissue," Dzau says. So the technique has not proved as effective as researchers had hoped.
Dzau's team theorized that after a heart attack there is not enough blood flow to the damaged area of the heart to support the transplanted stem cells.
Working with rats, the researchers genetically modified adult stem cells taken from a rat's bone marrow. To these stem cells they added a single peptide called Akt1, which is known to prevent cell death.
When these modified stem cells were injected into the damaged portion of the rat's heart, Akt1 became active, letting the cells survive. "These modified cells survived longer and functioned better than unmodified stem cells," Dzau notes.
"Our data shows that in rats receiving the altered stem cells, the heart almost completely healed and cardiac function was completely restored," he says. Dzau's team also found that as they increased the number of modified stem cells, the therapy became more effective.
Their research appears in the September issue of Nature Medicine.
Dzau speculates this finding opens the door to genetic manipulation of adult stem cells that can be used in restoring many types of damaged tissue, including cardiac and brain and spinal cord tissue.
"There is hope that by using adult stem cells, rather than embryonic stem cells, we can repair damaged tissue. But since adult stem cells have limitations, genetic manipulation can increase their capacity, making them more robust and better able to do the job," Dzau says.
Dr. Charles Murry, an associate professor of pathology at the University of Washington, says the interesting aspect of this study is that Dzau's team tackled the problem of cell death.
By using a know pathway of cell survival and translating it to stem cells, these researchers have shown a significant improvement in the ability of stem cells to survive and effect cardiac repair, he says.
"Coupling gene therapy with stem cell therapy gives you so much more power to control cell behavior," Murry stresses. "This line of research must be pursued."