Adult stem cell studies abound for heart, diabetes, MS; far ahead of embryonic resear

[Jeannine]

Adult stem cell studies abound for heart, diabetes, MS; far ahead of embryonic research

In June, for example, researchers reported they had restored vision to people whose eyes were damaged from caustic chemicals. Stem cells from each patient's healthy eye were grown and multiplied in the lab and transplanted into the damaged eye, where they grew into healthy corneal tissue.

A couple of months earlier, the Vatican announced it was funding adult stem cell research on the intestine at the University of Maryland. And on Friday, Italian doctors said they'd transplanted two windpipes injected with the recipients' own stem cells.

But these developments only hint at what's being explored in experiments across the United States.

Much of the work is early, and even as experts speak of its promise, they ask for patience and warn against clinics that aggressively market stem-cell cures without scientific backing.

Some of the new approaches, like the long-proven treatments, are based on the idea that stem cells can turn into other cells. Einhorn said the ankle-repair technique, for example, apparently works because of cells that turn into bone and blood vessels. But for other uses, scientists say they're harnessing the apparent abilities of adult stem cells to stimulate tissue repair, or to suppress the immune system.

"That gives adult stem cells really a very interesting and potent quality that embryonic stem cells don't have," says Rocky Tuan of the University of Pittsburgh.

One major focus of adult stem cell work for about a decade has been the ailing heart. While researchers remain committed, much of the early enthusiasm from patients, doctors and investors has slacked off because results so far haven't matched expectations, says Dr. Warren Sherman of Columbia University.

"Everyone, including myself, is impatient and would like to see positive results appear quickly," said Sherman, who hosts an annual international meeting of researchers. But he called for patience.

In treating heart attack, for example, studies show stem cell injections help the heart pump blood a bit better, Sherman said. But the research has not yet established whether injections cut the risk of death, more heart attacks or future hospitalizations, he said.

Sherman said he hopes a large study of those patient outcomes can be done in the next couple of years, and is "very optimistic that patients will benefit."

Similarly, in heart failure, research indicates stem cells can ease symptoms but larger studies are still needed to show how much good the treatments provide, he said. He noted that current studies are testing stem cells taken not only from bone marrow and leg muscle, but also from fat.

Another heart-related condition under study is critical limb ischemia, where blood flow to the leg is so restricted by artery blockage it causes pain and may require amputation. The goal here is to encourage growth of new blood vessels by injecting stem cells into the leg.

Sherman said limb ischemia research is moving fast and the results "are very, very encouraging."

The injected cells may serve as building blocks while also stimulating local tissue to grow the vessels, said Dr. Douglas Losordo of Northwestern University. His own preliminary work suggests such a treatment can reduce amputation rates.

Dr. Gabriel Lasala of TCA Cellular Therapy also has reported positive preliminary results. One success is Rodney Schoenhardt of Metairie, La.

Schoenhardt had already had surgery on both legs for the disease, and his surgeon was talking about amputating his left leg. Schoenhardt suffered so much pain in his left leg while standing that he used a wheelchair instead.

For Lasala's research, Schoenhardt got 40 shots in each leg about 18 months ago, with stem cells going into his left calf and a placebo dose into the other. Soon, he said, the pain in his left leg was gone.

Schoenhardt, 58, now mows his lawn, and he remodeled his living room to fix damage from Hurricane Katrina. "My wheelchair is in my garage, collecting dust," he said.

"I'm even thinking about taking up a little tennis again."

With all the heart-related stem cell studies, the former president of American Heart Association says, "We should be enthusiastic, but cautiously so." Beyond the promising indications of early studies, researchers need definitive evidence that the treatments not only make patients better but also don't cause unintended harm, says Dr. Clyde Yancy.

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