According to the Los Angeles County Department of Public Health, coronary heart disease is the leading cause of death in the county. For those individuals who survive their first heart attack, the risk of a second—and possibly fatal—heart attack is of significant concern. A new study by researchers at Cedars-Sinai Heart Institute in Los Angeles has reported that stem cells could potentially mend their broken hearts. The study was published online on February 13 in the journal Lancet.
The stem cells used in the study were not derived from human embryos; rather they were obtained from the patients’ heart cells. The study group was comprised of 25 patients (average age: 53) who had suffered heart attacks that left them with damaged heart muscle. Each patient underwent extensive imaging scans so that their physicians could pinpoint the exact location and severity of the scars, which appeared following the heart attack. The patients received their treatment at Cedars-Sinai Heart Institute and at Johns Hopkins Hospital in Baltimore.
"While the primary goal of our study was to verify safety, we also looked for evidence that the treatment might dissolve scar and regrow lost heart muscle," noted Eduardo Marbán, MD, PhD, the director of the Cedars-Sinai Heart Institute who invented the procedures and technology involved in the study. He added, “This has never been accomplished before, despite a decade of cell therapy trials for patients with heart attacks. Now we have done it. The effects are substantial, and surprisingly larger in humans than they were in animal tests.”
Eight patients served as controls; they received standard medical care for heart attack survivors, including prescription medicine, exercise recommendations, and dietary advice. The other 17 patients underwent a minimally invasive biopsy, under local anesthesia. Using a catheter inserted through a vein in the patient’s neck, the surgeons removed small portions of heart muscle, about half the size of a raisin. The biopsied heart tissue was then taken to Dr. Marbán’s specialized lab at Cedars-Sinai, using methods he invented to culture and multiply the cells. In the lab, the heart cells multiplied to between 12 and 25 million. They were then reintroduced into the patient’s coronary arteries via a catheter during a second, minimally invasive procedure.
The patients who received the infusion of cells experienced an average 50% reduction in their heart attack scars 12 months after infusion. In contrast, the control patients who received standard medical management did not experience any shrinkage of their scars.
While the procedure appears to be a revolutionary medical technique, Dr. Marban would like to investigate further a few perplexing aspects of the study. For example, while the patients grew new heart muscle and saw a dramatic reduction in scar tissue, the actual function of their hearts did not significantly improve. In addition, it appeared the stem cells themselves may not have turned into cardiac muscle, but rather they stimulated the heart to produce new muscle cells. Dr. Marban noted that because it was a “Phase 1” study, it was really meant to measure whether the procedure was safe. Of the 17 patients who were given the stem cell injections, six experienced “serious adverse events.” However, only one was regarded to be possibly related to the treatment.
The potential success of this research could hold significant promise for the millions of Americans who suffer from heart disease. If Dr. Marban’s future experiments yield the same results as this initial study, he believes he could be offering this therapy to patients within four years.
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