Heart Repair Boosted by Stem Cell Injections
By Steve Sternberg, USA Today, November 8, 2007
In an effort that has generated more debate than breakthroughs, researchers at the University of California, San Diego Medical Center reported small successes Wednesday in using stem cells to patch ailing hearts.
Embryonic stem cell are considered to be capable of differentiating into any tissue in the body, but are controversial due to the fact a human embryo must be destroyed to obtain them. Embryonic stem cells have also been a failure in treatment thus far. On the other hand, adult stem cells have treated many conditions successfully, and some sources show the potential to differentiate exactly like embryonic stem cells.
Researchers showed that the hearts pumping power can be increased by injecting muscle stem cells into heart attack patients. The California and Finish studies open yet another window into the future of heart attack care. The preliminary results are the most recent of several other heart related studies.
"If we can do this, we are going to see a complete revolution in medicine, how we treat heart disease and heart attacks," says Nabil Dib of the University of California, San Diego Medical Center.
However, the revolution is still years away. Doctors want to replace non-functioning heart tissue by implanting stem cells that will grow and replace the damaged areas, but they are still trying to determine how to do this. With tireless cells, a blood supply, and it's very own electrical system, the heart is a complex biological machine.
Over the past few years, modest, yet positive results have been observed in about two dozen trials. Researchers took stem cells from adult tissues and injected them into patients' hearts.
Joseph Wu of Stanford University says there are many questions that must be answered before research accelerates its pace. Key questions include, but are not limited to, "can stem cells be modified to become heart cells," and "how long can the cells survive after they have been injected."
Last year, three major studies showed mixed results. "One was positive, one was negative, and one was equivocal," Wu says. "Now we're back to the drawing board."
Scientific issues aren't the only obstacles.
"The added burden we have in the U.S. is that regulatory issues make it difficult to get anything off the ground," says Mariell Jessup of the University of Pennsylvania.
In the studies reported at a meeting of the American Heart Association:
•By taking hundreds of thousands of custom-cultured cells from a patient's thigh muscle, doctors concluded that it was safe and feasible to replace scarring from decade-old heart attacks. Some scientists question it, but the cells appeared to take root and grow. Jonathan Dinsmore of Mytogen, Incorporated, the company that cultures the cells, said that the treatment would likely exceed $100,000.
•A boost in pumping power compared to patients who did not get treatment was observed by doctors at two hospitals in Finland. Within a week of experiencing a heart attack, special bone marrow cells were injected into 39 patients.
"There clearly is a signal that cell therapy can contribute to recovery in acute (heart attacks)," says Andreas Zeiher of the University of Frankfurt, lead investigator of a larger study released last year that yielded similar findings.