hCSCs were injected into normal or infarcted hearts of nude rats. The injected cells were pooled from 2-3 different patient cultures. A magnetic-activated cell sorter with antibodies against human c-kit was used for cell culture enrichment prior to cell transplantation.
First, we injected 1x106 c-kit+ enriched cells into the myocardium of two non-infarcted athymic nude rats. After 1 week, the hearts were fixed, embedded. Sections were stained with an antibody to c-kit as well as human fetal cardiac α-actin to identify hCSCs and specifically human cardiac graft cells. Histological analysis revealed early sarcomere formation accompanied by the typical striation and positive staining for human fetal cardiac α-actin (green) (arrow) (b).
In the next experiment, 1x106 c-kit+ enriched cells were injected into the infarcted heart. Seven days after MI, animals were treated with a single injection of 1x106 c-kit+ enriched cells into the infarcted myocardium. One month after transplantation, a representative image shows a well organized, myocardial cell graft expressing human cardiac α-actin (white arrow) and connexin 43 (red, arrow) (a,). Nuclei are stained blue with DAPI.