Expanded CD[133.sup.+] Cells from Human Umbilical Cord Blood Improved Heart Function in Rats after Severe Myocardial Infarction

Pharmacological approaches are partially effective in limiting infarct size. Cell therapies using a cell population enriched with endothelial progenitor cells (EPCs) CD[133.sup.+] have opened new perspectives for the treatment of ischemic areas after infarction. This preclinical study evaluated the effect of intramyocardial transplantation of purified or expanded human umbilical cord blood-derived CD[133.sup.+] cells on the recovery of rats following acute myocardial infarction (AMI). Histology studies, electrocardiogram, and fluorescence in situ hybridization (FISH) were used to evaluate heart recovery. Purified CD[133.sup.+] cells, enriched in endothelial progenitor cells, when expanded in vitro acquired an endothelial-like cell phenotype expressing CD31 and von Willebrand factor (vWF). The group of infarcted rats that received expanded CD[133.sup.+] cells had a more significant recovery of contraction performance and less heart remodeling than the group that received purified CD[133.sup.+] cells. Either purified or expanded CD[133.sup.+] cells were able to induce neovascularization in the infarcted myocardium in an equivalent manner. Few human cells were detected in the infarcted myocardium of the rats 28 days after transplantation suggesting that the effects observed might be related primarily to paracrine activity. Although both cell populations ameliorated the infarcted heart and are suitable for regeneration of the vascular system, expanded CD[133.sup.+] cells are more beneficial and promising candidates for vascular regeneration.