Studies On Stem Cell Therapy After Heart Attack Show Mixed Results

April Flowers for redOrbit.com Your Universe Online

Conflicting studies were highlighted at this years American Heart Association Scientific Sessions meeting concerning stem cell therapy for heart attack patients.

The first study, from the University of Louisville and Brigham and Womens Hospital, reported holy grail results for a Phase I clinical trial: marked sustained improvement in all patients with zero adverse effects.

Roberto Bolli, M.D., of the University of Louisville and Piero Anversa, M.D., of Brigham and Womens Hospital presented data from their groundbreaking research in the use of autologous adult stem cells with patients who had previous heart attacks in a Late-Breaking Clinical Trial session.

The researchers report that all patients receiving the stem cell therapy showed improved heart function after two years, with an overall 12.9 absolute unit increase in left ventricular ejection fraction (LVEF). LVEF is a standard measure of heart function that shows the amount of blood ejected from the left ventricle during a heartbeat. They saw no adverse effects from the therapy. In fact, nine patients showed evidence of myocardial regeneration new tissue replacing formerly dead tissue killed by heart attack in MRI scans.

The trial shows the feasibility of isolating and expanding autologous stem cells from virtually every patient, said Bolli, who is the Jewish Hospital Heart and Lung Institute Distinguished Chair in Cardiology and director of the Institute for Molecular Cardiology in the Department of Medicine at UofL. The results suggest that this therapy has a potent, beneficial effect on cardiac function that warrants further study.

In all patients, cells with high regenerative reserve were obtained and employed therapeutically, said Anversa, professor of Anesthesia and Medicine at Brigham and Womens Hospital and Harvard Medical School. Our efforts to carefully characterize the phenotype and growth properties of the cardiac stem cells may have contributed to these initial positive results.

The Stem Cell Infusion in Patients with Ischemic CardiOmyopathy, or SCIPIO, trial was a randomized open-label trial of cardiac stem cells (CSCs) in patients who were diagnosed with heart failure following a myocardial infarction and had a LVEF of 40 percent or lower. A normal LVEF reading is 50 percent or higher.

The CSCs, referred to as c-kit positive cells because they express the c-kit protein on their surface, were harvested from 33 patients during coronary artery bypass surgery. The stem cells were then purified and processed so that they could multiply, and once an adequate number was produced about one million for each patient they were reintroduced into the region of the patients heart that suffered scarring during the heart attack.

At four months after infusion, the researchers report that LVEF increased from 29 percent to 36 percent for 200 patients. On average, the 13 control patients who did not receive a CSC infusion showed any improvement.

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Studies On Stem Cell Therapy After Heart Attack Show Mixed Results