For the first time, stem cells from patients' own hearts have been shown to battle heart failure.
In a small study of 16 patients, cardiac stem cells improved heart function and reduced the amount of tissue damage in patients with heart failure -- a disabling and lethal condition caused by the death of heart muscle tissue.
"If this is confirmed in further studies, it could offer an entirely new option and a potential cure for patients who are now dying from heart failure," said Dr. Roberto Bolli, director of cardiology at University of Louisville and lead author of the study published today in The Lancet.
Cardiac stem cells have the potential to divide and develop into cardiomyocytes -- the muscle cells that make the heart contract and pump blood.
Among 14 patients who responded to the stem cell treatment, the heart's blood-pumping efficiency increased from 30.3 percent before the treatment to 38.5 percent after. And in seven patients who underwent magnetic resonance imaging, the amount of dead heart muscle tissue decreased by 24 percent over four months and 30 percent over a year.
Seven control patients who did not receive the stem cell treatment showed no improvement.
"What is really exciting about the use of cardiac stem cells is we think we're attacking the fundamental problem: replacing dead tissue with new cardiac muscle," said Bolli. "Again, if these results are confirmed, this would be a true revolution in medicine; one of the biggest advances in cardiology in my lifetime."
Stem cell-treated patients also reported feeling better and more capable of doing daily activities.
Mike Jones, the very first patient to receive the treatment in July 2009, said it not only gave him more years to live, but a better quality of life during those years.
"Now I can do more with my grandkids," said Jones, 68, who lives in Louisville. "I pitched softballs with my granddaughter for probably 15 minutes today. I got a little bit winded at the end, but that's something that before the stem cells would have been just impossible."
Jones suffered a massive heart attack in 2004. And in the years that followed, even a short browse through the local Home Depot became too taxing for his ticker.
"Sometimes I'd have to take two [nitroglycerin] tablets for chest pain; sometimes I'd have to go sit down for a few minutes," said Jones, who owned a painting and remodeling business before retiring in December 2010. "But that doesn't happen at all anymore."
The study is the first in humans to use cardiac stem cells, which were collected from patients' hearts during coronary artery bypass surgery. The cells were then purified and prepared for infusion back into the damaged tissue -- a process that takes up to six weeks.
Other studies have examined the potential of stem cells from patients' bone marrow to reverse the damage caused by heart attacks, with mixed results. Bone marrow stem cells are capable of becoming a variety of cell types -- from blood cells to bone cells -- whereas cardiac stem cells are more specialized, and further along to road to becoming heart cells.
"This group has shown that you can prepare cardiac-specific stem cells and these cells are much more potent at cardiac repair than bone marrow cells," said Dr. Joshua Hare, professor of cardiology and director of the Interdisciplinary Stem Cell Institute at University of Miami.
But bone marrow stem cells are much easier to extract and prepare.
"From a convenience standpoint, it's obviously much easier to get the bone marrow," said Hare, explaining that bone marrow can be drawn from patients' bone and quickly turned around for reinjection into the heart. "The downside is they're not as effective. Clearly cardiac stem cells work so much better."
Another study published today in JAMA, the Journal of the American Medical Association, found no benefit of injecting bone marrow stem cells into damaged heart tissue two-to-three weeks after a heart attack. But researchers are still investigating whether earlier delivery -- within a week after a heart attack -- is effective.