In the trial, participants' cardiac tissue will be harvested, the stem cells isolated and then expanded in vitro from about 500 cells to 1 million cells over several weeks, Bolli explained. Several months after the patient has undergone bypass surgery, the stem cells will be re-injected.
Researchers believe the stem cells can differentiate into new heart muscle and blood vessel cells. In addition, the stem cells release cytokines, substances that stimulate the heart's internal repair system, Bolli said.
The clinical trial is still enrolling participants, and it's too soon to tell how patients who have had the procedure are faring, Bolli said.
For cancer patients, doxorubicin and other medications in the class of chemotherapy drugs called anthracyclines, can be potent tumor fighters. However, oncologists often must limit doses because of the risks to the heart, Anversa said.
If future research shows the stem cell procedure is safe and effective in people, it could one day mean doctors could give higher doses of chemotherapy drugs, knowing that if stem cells are harvested, there is the ability to repair damage to the heart down the line.
"For people, this could potentially be a very important development," Bolli said. "Doxorubicin is a very effective anti-cancer drug, but the use is limited by the toxicity. If this issue can be overcome, it would be a major leap forward for anti-cancer therapy."
The National Cancer Institute has more on doxorubicin and heart risks.
SOURCES: Piero Anversa, M.D., director, Center for Regenerative Medicine, Departments of Anesthesia and Medicine and Cardiovascular Division, Brigham and Women's Hospital, Boston; Roberto Bolli, M.D., chi
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