Trial to Treat Heart Attack Patients with Stem Cells
April 15, 2008 - Physician scientists at the Texas Heart Institute (THI) at St. Luke's Episcopal Hospital have begun the world's first clinical trial to treat heart attack patients with a special type of stem cell to promote better healing and to prevent congestive heart failure, which many patients develop following a heart attack.
Almost six million Americans have congestive heart failure, a progressive form of cardiovascular disease that inhibits the heart from pumping blood throughout the body, and 550,000 new cases are diagnosed each year. About half of these patients die within five years after receiving a diagnosis of severe heart failure.
Stem cell transplantation offers new hope for treating heart failure. Stem cells are "generic" cells that can regenerate themselves and develop into specialized cells, such as cardiac cells. In stem cell therapy, stem cells are typically removed from another part of the patient's body -- usually the bone marrow or the blood, both of which contain a variety of stem cell types. The cells are then transplanted into the heart, where they can lead to the growth of new heart muscle and blood vessels to replace damaged tissues.
The special stem cells used in this study, known as mesenchymal precursor stem cells, are allogenic, meaning that they have been taken from the bone marrow of a healthy donor and grown in cultures to provide a plentiful supply. These cells, which are injected directly into the heart with a special catheter, appear not to provoke rejection by the recipient or cause inflammation.
The first patient to receive the treatment is a 65-year-old man. The man's heart attack was treated with angioplasty to open the obstructed vessel, and he received a stent, a spring-like device, to keep the vessel open. He had the stem cell procedure in the catheterization laboratory ten days after having his heart attack, and he was discharged from the hospital two days after receiving this experimental treatment.
"Our pre-clinical trials have established that ten days after the heart attack is the optimal time to give this treatment. The heart is still inflamed in the days just after a heart attack. If we wait too late, the heart will have too much scar tissue and its ability to pump will already be compromised," said Emerson Perin, M.D., Ph.D. Dr. Perin is the director of the Texas Heart Institute's Stem Cell Center and he was recently appointed Director of Clinical Research for Cardiovascular Medicine at THI.
This randomized Phase I trial will include 25 patients in three phases in which the patient receives 25, 75 or 150 million stem cells. Physicians use a 3-D imaging technology which maps the electrical and mechanical function of the left ventricle, the main pumping chamber of the heart. The stem cells are injected into damaged but still viable areas of the heart muscle. The study is sponsored by Angioblast Systems, a company which provides the proprietary cells.
"This is a major milestone in the adult stem cell research we began eight years ago. Our challenge remains to identify the very best types of stem cells, refine our delivery techniques, and establish the most effective doses of stem cells. We also have much work to do in understanding the molecular mechanisms by which stem cells differentiate into specific organs and tissue," said James Willerson, M.D., president-elect and medical director of the Texas Heart Institute at St. Luke's. He is also President of The University of Texas Health Science Center at Houston.
Dr. Willerson made the point that every person is a product of two cells which develop into billions of stem cells that have the innate ability to form our bodies.
"All of us have stem cells in our bodies, just not in sufficient numbers to perform the healing we need. I believe we were meant to learn of the powerful potential of stem cells and build on it. In the coming years, this could be an accepted stem cell therapy at hospitals. Ultimately, stem cell research could give us the ability to regenerate whole hearts," said Dr. Willerson.
Drs. Perin and Willerson and their team have developed a network of several hospitals to identify patients who may fit the criteria to be enrolled in this trial.
"We're already seeing promising results from treating patients with severe heart failure with their own stem cells. With this study, we hope to find a way to help patients before they get so sick," said Dr. Perin.
For more information: www.texasheart.org