ROYAL OAK, Mich. (AP) - Doctors said Wednesday they are attempting an experimental procedure to heal a teenage patient's heart by infusing it with the boy's own blood stem cells. It could take months to know whether it works, but doctors say they are already seeing encouraging results.
Doctors at William Beaumont Hospital said the procedure on 16-year-old Dmitri Bonnville is believed to be the first of its kind.
Animal studies have shown that stem cells - the body's building blocks for all types of tissue - can be injected to grow new muscle and blood vessels, and researchers have expressed hope that the research could eventually help repair human hearts and other tissue.
Dmitri was working on a house remodeling project Feb. 1 when a co-worker playing with a nail gun accidentally fired a 3-inch nail into his chest. Doctors removed the nail and patched the hole, but Dmitri soon suffered a heart attack that caused serious tissue death, severely reducing his heart's pumping efficiency.
On Feb. 17, doctors began giving Dmitri a drug to stimulate his bone marrow to make more blood stem cells - a type that does not carry the ethical questions raised regarding embryonic stem cells. A few days later, they harvested the cells and injected them into an artery that supplies blood to the heart.
The boy's heart's efficiency had increased within a few days, said Dr. Cindy Grines.
Stem cell researchers not involved in the experiment said they knew of no similar research in humans. There already is some evidence, however, that stimulating stem cell production alone can cause tissue regeneration, without having to inject cells into a particular area.
"I think it's extremely hopeful," said Dr. Neil D. Theise, a stem cell researcher at Beth Israel Medical Center in New York.
But even if Dmitri continues to improve, it may be hard to know whether the therapy worked, and if so, how it worked, said Dr. Sam Dudley, a cardiologist at Emory University in Atlanta also involved in stem cell research.
"I think this is a wonderful thing that they did," Dudley said. But he added that carefully conducted studies will be needed before stem cell therapy becomes standard.
"We have to go judiciously because we need to know a little bit more what we're doing," he said.
Beaumont doctors said they hope to proceed to clinical trials of their technique, which they said was the boy's only alternative to a heart transplant.
The heart should be able to continue repairing itself for about three months, said Dr. William O'Neill, Beaumont's chief of cardiology. By then, it should be clear how much good the treatment did.
