MONDAY, Oct. 13, 2003 (HealthDayNews) -- Infusing a patient's own stem cells into a heart artery several days after a heart attack improves the heart's pumping power and speeds the healing process, German cardiologists report.
The stem cell infusions increased the amount of blood ejected by the left ventricle, the heart's main pumping center, by nearly 20 percent and decreased tissue damage by 20 percent, the study says.
The findings, by researchers at the University of Frankfurt, appear in the Oct. 14 issue of Circulation.
The study included only 28 patients, and the journal report covers just the first four months of treatment. But encouraging longer-term results have prompted the start of a larger trial, says study author Dr. Andreas M. Zeiher, chairman of the university's department of medicine.
"We now have a 12-month follow-up, and the improvement is preserved over this time," Zeiher says. "Not a single patient in the trial developed heart failure."
Heart failure, a progressive loss of ability to pump blood, often occurs after a heart attack. The American Heart Association estimates that more than 51,500 Americans will die of heart failure this year.
The stem cell treatment used by the Frankfurt scientists avoids the ethical issues of fetal stem therapy because it uses adult stem cells -- Zeiher prefers the term "progenitor cells." These cells are more limited than fetal stem cells, but they are still valuable for their ability to transform themselves into a variety of cells, including heart muscle cells.
Some patients in the trial got adult stem cells derived from bone marrow, while others get heart-derived cells. Both were equally effective, Zeiher says.
The trial now starting in Frankfurt will include 60 patients. Half will get stem cells, the other half inactive cells. This "randomized, double-blind" experiment -- meaning neither patients nor doctors know which patients are getting the treatment -- is essential for verifying that the therapy works, Zeiher says.
Several cardiology teams in the United States are eager to start similar trials, but are waiting for approval by the U.S. Food and Drug Administration (FDA), says Dr. William O'Neill, director of cardiology at William Beaumont Hospital in Detroit.
"Basically, all of these groundbreaking trials will be done in Europe," says O'Neill, who has submitted an application for FDA approval.
In the German trial, the heart attack survivors first had angioplasty, in which a balloon was inserted to reopen a blocked artery that caused the heart attack. A metal-meshed tube called a stent was then inserted to keep the artery open. The stem cells were inserted into the stented portion of the artery an average of 4.7 days after the heart attack.
The effect of the treatment on the heart muscle was assessed by using a technique called dye-enhanced magnetic resonance imaging. It showed the average amount of blood ejected by the left ventricle increased from 44.1 percent to 48.9 percent; an undamaged ventricle ejects about 60 percent of its blood with each beat.
Zeiher and his colleagues clearly are leading the stem cell therapy effort, O'Neill says. The human trial was done after a number of studies in laboratory dishes and animals.
"He is really the pioneer," O'Neill says.
An important part of the pending human trial will be to show that infused stem cells can migrate from an artery into the heart muscle and form new, healthy tissue, O'Neill says. "The more likely they are to migrate, the more likely they are to home in on damaged areas and improve heart function," he says.