Skeletal myoblast transplantation: No MAGIC bullet for ischemic cardiomyopathy

Therapies for end-stage heart failure are limited by the donor shortage for heart transplantation and the shortcomings of left ventricular assist devices for destination therapy. Treatments that use stem cells to 'rebuild' the myocardium are, therefore, desirable. Such therapies use either stem cells derived from bone marrow or skeletal myoblasts. In clinical trials, however, neither method of administration has demonstrated an improvement in ventricular function. The MAGIC trial was a randomized, placebo-controlled study of high and low doses of skeletal myoblasts injected into the myocardium of patients with MI undergoing CABG surgery. No difference in left ventricular ejection fraction was noted in the cell-treated groups when compared with controls, although patients who received the high dose of myoblasts had a decrease in ventricular dimensions, raising the possibility of an antiremodeling effect. A higher incidence of ventricular arrhythmias was observed in the myoblast groups than in control patients.