University of Utah researchers are studying whether an individual's own stem cells can build new blood vessels and forestall the need for leg amputations.

The U. is one of 15 national sites in a clinical trial led by Northwestern University in Illinois, looking at whether stem cells can save those limbs in patients who have severe peripheral vascular disease.

That is atherosclerosis that affects the limbs, caused by the same processes that lead to heart attack and stroke, including such factors as diabetes, smoking, high blood pressure and high cholesterol, said Dr. Larry W. Kraiss, professor and chief of vascular surgery at the U. School of Medicine, who is co-principal investigator for the U. study.

Managing those risk factors is the most effective treatment, he said. When blockages do occur, balloon angioplasty, stents and bypass surgery may be treatment options, but for some, they don't work or aren't appropriate. Meanwhile, tissue that's not getting blood is in danger of dying, and amputation is the sole remaining traditional option.

Individuals ages 21 to 80 who are not currently sick or in kidney failure, but who have peripheral vascular disease that would require amputation, are being sought for the three-arm study: high-dose stem cells, low-dose stem cells or placebo.

Participants are given a daily shot for five days of medication to increase the number of white blood cells and move them into the bloodstream from the bone marrow. That's believed to be the riskiest part of the study, Kraiss said, and participants are being asked to stay close by in case of complication.

Next, the blood is taken out of the patient and run through a machine that pulls out the white blood cells, where the stem cells are. The CD-34 cells in the white cells are isolated from other cells and purified and concentrated at the U. cell therapy lab. They'll be injected into the leg near the blockage, where it's believed that the stem cells will note the need for more blood vessels and respond by making them.

It's a blinded, randomized study, so patients and doctors will not know who's getting the stem cells and who is receiving a saltwater placebo injection. The investigators will follow participants for a year and expect they'd see improvement within six weeks to three months, Kraiss said. Although this is the first study in humans, the process worked in lab mice. He said if results of the multicenter study are positive, a larger study will follow.

Kraiss says about 2,000 Utahns have critical limb ischemia. It's natural for the U. to participate in a study designed to try to save limbs, because it has long been a referral center for limb salvage.

Linda L. Kelley, Ph.D., associate professor of internal medicine and director of the U.'s cell therapy lab, is co-principal investigator. To learn more or enroll, call 801-585-3663 or 1-800-824-2073.


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