University of Louisville cardiologist Roberto Bolli, MD, led the stem cell study that tested using patients' own heart stem cells to help their hearts recover from heart failure. Though that trial was preliminary, the results look promising -- and may one day lead to a cure for heart failure.
Here, Bolli talks about what this work means and when it might become an option for patients.
How long until this becomes available?
"Realistically, this will not come... for another three or four years, at least," Bolli says. "It may be longer, depending on the results of the next trial, of course."
Larger studies are needed to confirm the procedure's safety and effectiveness. If those succeed, it could be "the biggest advance in cardiovascular medicine in my lifetime," Bolli says.
How are the other patients in the first trial doing?
A total of 20 patients took part in the initial study.
All of them experienced significant improvement in their heart failure and now function better in daily life, according to Bolli. "The patients can do more, there's more ability to exercise, and the quality of life improves markedly," Bolli says.
Bolli's team published its findings on how the patients were doing one year after stem cell treatment in November 2011 in the Lancet, a British medical journal.
Each patient was infused with about 1 million of his or her own cardiac stem cells, which could eventually produce an estimated 4 trillion new cardiac cells, Bolli says. His team plans to follow each patient for two years after their stem cell procedure.
Keep in mind that this was a phase I study. Those focus on safety more than effectiveness.
How does this compare to other stem cell trials?
The results were "much more striking" than past stem cell trials to heal the heart, Bolli says.
This trial was the first in the world to use stem cells derived from the heart. Earlier studies used stem cells gleaned from different bodily sources, including bone marrow, adipose (fat) tissue, and circulating blood. Those showed either no improvement or only modest gains in a patient's left ventricular ejection fraction, a measure of the heart's pumping ability.
In contrast, one year after being injected with their own heart stem cells, Bolli's patients gained an average increase of 10 percentage points in ejection fraction.
For example, a patient with a baseline ejection fraction of 30% would have increased to 40%, he says.
"That is huge when you consider that previous studies of stem cells in these kinds of patients -- patients with ischemic heart failure -- have reported improvements of three, four, five [percentage] points in ejection fraction," Bolli says.
Also, in Bolli's patients, cardiac tissue scarred by heart attack had shrunk by an average of 50% one year after the experimental procedure.
"This is amazing," Bolli says. "You are given one shot of stem cells and that scarring in the heart shrinks by half in one year. Correspondingly, there's an increase in viable tissue in the heart, which is strongly suggestive of regeneration."
In other words, the patients are making new heart tissue to replace the damaged tissue -- something no drug or surgery can do.
Two years after the procedure, partial results were available for eight patients who had gotten echocardiograms. On average, their ejection fraction had improved by 13 percentage points.
"At two years, we continue to see the improvement in ejection fraction," Bolli says. "It actually seems to be greater than it is at one year. So in other words, as time goes by, the effects of these cells becomes bigger, rather than smaller, which is really quite exciting."
What about cost?
Such a regenerative therapy would be less costly and burdensome than current options for heart failure, including a heart transplant or a mechanical pump called a ventricular assist device, Bolli says.
Also, Bolli hopes to make the heart stem cell procedure available to a much larger pool of heart failure patients. During the Phase I trial, all 20 patients had undergone heart bypass surgery, during which surgeons extracted heart tissue that contained stem cells.
Patients won't need to undergo bypass surgery for the next clinical trials.
"Now we can isolate the stem cells from a biopsy. We don't need a surgical specimen anymore," Bolli says.
To get those biopsies, the researchers will guide a catheter through the neck's jugular vein to the right side of the heart, where they'll take a tiny piece of tissue. It's an outpatient procedure that's already routinely done in patients being evaluated for heart transplants.
"It can be done very easily and not very expensively, and it makes every heart failure patient a potential candidate for these cells," Bolli says.