University of Florida doctors on Wednesday (Oct. 3) treated their first patient enrolled in a new study designed to test whether injecting stem cells into the heart helps restore blood flow to the organ by prompting new blood vessels to grow.
UF researchers plan to test the experimental therapy in people with severe coronary artery disease and daily chest pain who have not responded to traditional medications or surgical procedures designed to restore blood flow, such as angioplasty or bypass surgery.
“The general idea is that by providing these cells of blood vessel origin, we hope to either generate new blood vessels from the growth of these implanted cells or stimulate the heart to regenerate new blood vessels from the cells that reside in it,” said study investigator Carl J. Pepine, M.D., chief of cardiovascular medicine at UF's College of Medicine. “It's not completely clear whether it's the actual cell itself that would do this or whether it's just the milieu and the chemical signals that occur from the cells that would result in this.”
Each year, nearly half a million Americans with heart disease experience severe chest pain because coronary arteries and the smaller vessels that supply oxygen-rich blood to the heart muscle become narrowed or blocked by plaque deposits or clots. These blockages can trigger mini-heart attacks that, while too small to be noticed as they occur, over time irreversibly damage the heart — leading to disability, progressive heart failure or even death.
In the prospective, double-blind, placebo-controlled study, known as the Autologous Cellular Therapy CD34-Chronic Myocardial Ischemia Trial, or ACT34-CMI, UF researchers will study 15 Shands at UF medical center patients to determine whether a person's own stem cells can be used to effectively and safely treat chronic reductions in blood flow to the heart, improving symptoms and long-term outcomes. They also will evaluate whether participants report improved quality of life and exercise tolerance, and whether the heart functions better.
Participants will undergo screening tests and then receive a series of injections of a protein that releases stem cells from the bone marrow into the bloodstream. The cells, known as CD34+ stem cells, help spur blood vessel growth and are harvested from the patient during a procedure called apheresis, said Chris Cogle, an assistant professor of medicine at the UF's College of Medicine Program in Stem Cell Biology and Regenerative Medicine.
Participants will then be randomly assigned to receive one of two dosing levels of the cells, or a placebo.
“Physicians will use a catheter-based electrical mapping system to find muscle they think is still viable but not functioning,” said R. David Anderson, an associate professor of medicine at UF and director of interventional cardiology. “The cells are injected into viable sites in the heart, which have poor blood flow, in the cardiac catheterization laboratory at Shands at UF medical center.”
Patients will be periodically evaluated by echocardiography and magnetic resonance imaging over the course of a year after the procedure. Although to date study subjects have tolerated this procedure well, potential risks include infection, allergic reactions, bleeding, blood clots and damage to the heart or its vessels.