Studies: Stem cells reverse heart damage
[...] Conventional wisdom took a hit Monday, as Bolli's group and a team from Cedars-Sinai each reported that stem cell therapies were able to reverse heart damage, without dangerous side effects, at least in a small group of patients.
In Bolli's study, published in The Lancet, 16 patients with severe heart failure received a purified batch of cardiac stem cells. Within a year, their heart function markedly improved. The heart's pumping ability can be quantified through the "Left Ventricle Ejection Fraction," a measure of how much blood the heart pumps with each contraction. A patient with an LVEF of less than 40% is considered to suffer severe heart failure. When the study began, Bolli's patients had an average LVEF of 30.3%. Four months after receiving stem cells, it was 38.5%. Among seven patients who were followed for a full year, it improved to an astounding 42.5%. A control group of seven patients, given nothing but standard maintenance medications, showed no improvement at all.
"We were surprised by the magnitude of improvement," says Bolli, who says traditional therapies, such as placing a stent to physically widen the patient's artery, typically make a smaller difference. Prior to treatment, Mike Jones couldn't walk to the restroom without stopping for breath, says Bolli. "Now he can drive a tractor on his farm, even play basketball with his grandchildren. His life was transformed."
"This is unprecedented, the first time anyone has grown living heart muscle," says Marban. "No one else has demonstrated that. It's very gratifying, especially when the conventional teaching has been that the damage is irreversible."
Perhaps even more important, no treated patient in either study suffered a significant health setback.
The twin findings are a boost to the notion that the heart contains the seeds of its own rebirth. For years, doctors believed that heart cells, once destroyed, were gone forever. But in a series of experiments, researchers including Bolli's collaborator, Dr. Piero Anversa, found that the heart contains a type of stem cell that can develop into either heart muscle or blood vessel components -- in essence, whatever the heart requires at a particular point in time. The problem for patients like Mike Jones or Ken Milles is that there simply aren't enough of these repair cells waiting around. The experimental treatments involve removing stem cells through a biopsy, and making millions of copies in a laboratory.
The Bolli/Anversa group and Marban's team both used cardiac stem cells, but Bolli and Anversa "purified" the CSCs, so that more than 90% of the infusion was actual stem cells. Marban, on the other hand, used a mixture of stem cells and other types of cells extracted from the patient's heart. "We've found that the mixture is more potent than any subtype we've been able to isolate," he says. He says the additional cells may help by providing a supportive environment for the stem cells to multiply.
Bolli says he'll have to temper his enthusiasm until he can duplicate the results in larger studies, definitive enough to get stem cell therapy approved as a standard treatment. "If a phase 3 study confirmed this, it would be the biggest advance in cardiology in my lifetime. We would possibly be curing heart failure. It would be a revolution."
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