[Stem cells after myocardial infarction].

Loss of contractile myocardial tissue after myocardial infarction is followed by a remodeling of the left ventricle and clinical manifestation of heart failure, associated with a reduced life expectancy. One possibility to counteract the remodeling process would be to regenerate cardiomyocytes and to improve neovascularization in the infarct area. Indeed, experimental studies demonstrate that transplantation of adult stem or progenitor cells such as circulating, endothelial progenitor cells (CPCs) or progenitor cells derived from the bone marrow, is a therapeutic strategy to improve neovascularization and left ventricular (LV) function after myocardial infarction. First clinical trials in patients after an acute myocardial infarction indicate that intracoronary transplantation of adult progenitor cells is feasible and safe. Furthermore, patients treated with progenitor cells experienced an unexpectedly large improvement of LV function and geometry as well as vascularization, indicating a beneficial effect of the progenitor cell treatment on the postinfarction course. Randomized trials have obtained mixed results with respect to improvement of LV function after intracoronary infusion of progenitor cells, which may be due to methodological differences. However, in the largest trial, REPAIR-AMI, LV function significantly improved in progenitor cell-treated patients compared to a double-blind, randomized placebo-control group. Of note, that trial used a previously validated processing of progenitor cells with respect to in vitro and in vivo progenitor capacity of the cells. The data available, therefore, encourage assessing the efficacy of intracoronary infusion of progenitor cells-established to be efficient in previous trials-after acute myocardial infarction in larger, randomized controlled trials in order to assess the effect on mortality and morbidity.