A physician from the Indiana University School of Medicine is using adult stem cells to treat peripheral artery disease, a painful circulatory problem in the legs believed to affect 10 million Americans. Dr. Martin Murphy, an assistant professor of surgery, has injected 15 PAD patients with stem cells taken from their own bone marrow as part of an early-phase clinical trial, according to IU. The treatment is based on a theory that some people get PAD because their bodies don't produce enough "progenitors," specialized cells that promote the growth of new blood vessels. Consequently, their bodies do a poor job of repairing damaged cells in the blood vessels, leading to diseased arteries. The usual treatment, surgical vein grafts, is unlikely to help them, and they wind up needing amputations. According to Murphy, the stem cell treatment appears to be safe as none of the 15 patients in the trial has required amputation. The next step will be to try the treatment in a much larger group of patients.