However, another study presented at the meeting found that waiting 10 to 20 days after a heart attack to infuse bone marrow stem cells may be too long. The findings will also appear in the Nov. 14 online edition of the Journal of the American Medical Association.
The study involved 87 patients who had undergone angioplasty and/or placement of an artery-opening stent after heart attack. The researchers injected stem cells into the patients' hearts about two to three weeks after a heart attack -- only to find that therapy did not improve heart function after six months.
"When you have such a brand new treatment, negative data can be just as helpful as positive data," said Hare, who also wrote a JAMA editorial that accompanied the study . The take-home message, according to Hare: "This is too late to give the cells to the heart."
Study co-author Dr. Robert Simari, a cardiologist at the Mayo Clinic in Rochester, Minn., agreed. "We are modifying our prior enthusiasm for bone marrow stem cells and developing some framework for their use," he explained.
Stem cells sourced from bone marrow are not the only type being studied in this way, however. A third study looked at the use of stem cells originating from the patient's own heart.
The results of a phase 1 (early) clinical trial presented at the AHA meeting, published simultaneously in The Lancet, found real benefit from cardiac stem cell infusions for heart failure patients who had suffered a heart attack. This is the first time this approach has been tested in humans, the team said.
In the Stem Cell Infusion in Patients with Ischemic Cardiomyopathy (SCIPIO) study, researchers retrieved cardiac cells from individ
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