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German scientists have promising results from an experimental treatment to mend a broken heart. The treatment involves taking a heart attack patient's bone marrow cells and then injecting those cells into the arteries of the patient's heart.
NPR's Joe Palca has the story.
JOE PALCA: The job of cells in the bone marrow is primarily to make new blood cells. But if you inject bone marrow cells into a heart that isn't beating so well, something in the bone marrow seems to make the heart beat better.
At least that's what happened in animals. Andreas Zeiher and his colleagues at the University of Frankfurt wanted to see if the same thing would happen in humans. Small studies suggested it would, so he set up a larger study. Two hundred heart attack patients were divided into two groups. One group got their own bone marrow cells injected into their heart blood vessels. The others got an injection, but it contained no cells. Zeiher then measured how well the heart pumped four months after the injections.
Dr. ANDREAS ZEIHER (University of Frankfurt): In the control group receiving placebos or no cells, there was a minor improvement by roughly 3 percent in absolute percentage points. And in the cell-treated patients, the improvement was absolute 5.5 percent.
PALCA: That's a pretty modest improvement. But as he reports in tomorrow's New England Journal of Medicine, it's not just that their hearts pump better. Zeiher says after one year, the patients getting bone marrow cells had fewer heart problems.
Dr. ZEIHER: Suggesting that this minor improvement in functional recovery of pump function actually might indeed translate into a better clinical outcome.
PALCA: At Johns Hopkins Medical School, Joshua Hare is also working on a therapy that would use bone marrow cells to treat heart patients. Hare says others besides Zeiher have shown that bone marrow cells can improved a damaged heart's pumping ability.
Dr. JOSHUA HARE (Johns Hopkins Medical School): The next step in the development of a therapy is to show that something actually makes people feel better or live longer, and that is what he showed in the study.
PALCA: Zeiher is about to launch a study of 1,200 patients to confirm these results. But Ketil Lunde and his colleagues at the National Hospital of Norway have results that are not as encouraging. Lunde also has a report on bone marrow cells in this week's New England Journal of Medicine. Like Zeiher, he had two groups, one that received cells and one that didn't. And like Zeiher, Lunde looked for a change in the heart's ability to pump.
Dr. KETIL LUNDE (National Hospital of Norway): We found no difference between the groups.
PALCA: Lunde says the German group may have seen an improvement because they studied more patients.
Dr. LUNDE: I think that stem cell therapy will be useful for patients, but we think the technique needs to be further developed.
PALCA: Lunde says that development should take place in the lab, not the clinic. And besides, scientists can't really explain why bone marrow cells should help the heart function at all. But if they do, who cares how?
Dr. DOUGLAS LASORDO(ph) (Tufts University): You can't wait for the full, complete knowledge. I still don't know how aspirin works, but I prescribe it every day.
PALCA: Douglas Lasordo of Tufts University is also testing a bone marrow based therapy for the heart. Lasordo says if the Norwegian and German studies had both been negative, he'd be more pessimistic.
Dr. LASORDO: But the fact that well executed, controlled clinical trials show positive results in these patients, it's a reason to go forward.
PALCA: Lasordo says the German scientists are right to go forward and he hopes others will as well.
Joe Palca, NPR News, Washington.
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