Pharmacology
Endothelial progenitor cells come as a new hope for patients with Peripheral Vascular Disease (PVD)
By Akanksha,Pharmacology Correspondent
Jan 24, 2005, 18:51

Patients with PVD have decreased blood flow to the muscles of the legs, especially during exercise, which causes pain, aching, cramping or fatigue in the muscles of their legs when they walk,a condition known as "intermittent claudication."

Physicians at Emory University School of Medicine are conducting a clinical trial using stem cells generated within the bone marrow to grow new blood vessels that could improve circulation in these patients.

Decreased blood flow in the legs is caused by the blockage or narrowing of the arteries due to build-up of cholesterol. Normally, with exercise, the blood vessels dilate (get bigger), but clogged blood vessels constrict during exercise. In some individuals the vascular system corrects the problem on its own either by forming new blood vessels, called "collaterals," that bypass the blockages, or by repairing the diseased blood vessels. This repair process results in improved circulation even during exercise. Some people are not able to repair their own vessels, however, and physicians don't completely understand the reasons why.

This research team, led by cardiologist Arshed A. Quyyumi, MD, and cardiology fellow Veerappan Subramaniyam, MD, is using colony stimulating factors (growth factors), to prod the bone marrow to release a type of stem cells called endothelial progenitor cells, which are used by the body to form new blood vessels or to repair damaged ones.

Studies have shown that when muscles do not receive enough blood, the body makes growth factors that stimulate the bone marrow to release stem cells that "home" to the muscle that is not getting enough blood. These stem cells include endothelial progenitor cells (EPCs), which is the type of cell needed to make new blood vessels and to repair damaged ones.

Patients in the clinical trial will be given an injection of either a growth factor called GM-CSF (granulocyte-macrophage colony stimulating factor) or placebo (sterile salt water) three times a week for two weeks. The level of EPCs in the volunteers' blood will be measured before, during and after administration of the drug or placebo. The study is randomized and blinded, which means that volunteers will not know whether they are receiving the study drug or the placebo.

The goal of the study is to determine if and how much GM-CSF will increase the number of circulating EPCs in patients with peripheral vascular disease. Another goal is to find out whether or not increasing the number of circulating EPCs results in improved blood flow to the leg, improved blood vessel function and improvement of patients' symptoms.

FDA has already approved GM-CSF for several uses, including in cancer patients to increase the number of white blood cells to fight infection after chemotherapy; in healthy individuals serving as bone marrow donors to stimulate the bone marrow to release stem cells; and in patients who have had a bone marrow transplant to increase the number of white blood cells.

It is still considered experimental, however, for use to increase the level of EPCs in patients with peripheral vascular disease.

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The Robert W. Woodruff Health Sciences Center is an academic health sciences center committed to providing the best care for patients, educating health professionals and leaders, pursuing discovery research in all of its forms, and serving the community.
The Woodruff Health Sciences Center includes:
Emory Healthcare,Emory University School of Medicine,Nell Hodgson Woodruff School of Nursing,Rollins School of Public Health,Winship Cancer Institute,Yerkes National Primate Research Center and a wide array of other nationally known research centers.

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