Impact of cardiac stem cell sheet transplantation on myocardial infarction

Myocardial infarction (MI) remains a major cause of mortality because of the limited regenerative capacity of the myocardium. Transplantation of somatic tissue-derived cells into the heart has been shown to enhance the endogenous healing process, but the magnitude of its therapeutic effects is dependent upon the cell-source or cell-delivery method. We investigated the therapeutic effects of C-Kit positive cardiac cell (CSC) cell-sheet transplantation therapy in a rat model of MI. CSCs of human origin were sorted and cultured to generate scaffold-free CSC cell-sheets. One-layered or 3-layered cell-sheets were transplanted into nude rats 1 h after left coronary artery ligation. We observed a significant increase in the left ventricular ejection fraction and a significant decrease in left ventricular systolic dimension at 2 and 4 weeks in the 3-layer group, but not in the 1-layer or sham groups. Consistently, there was less accumulation of interstitial fibrosis in the 3-layer group than in the 1-layer or sham groups. Moreover, capillary density was significantly greater in the 3-layer group than in the 1-layer or sham groups. The 3-layered cell-sheet improved cardiac function associated with angiogenic and anti-fibrotic effects. Thus, CSC is a promising cell-source to use with the cell-sheet method for the treatment of cardiac failure, as long as a sufficient number of cells are delivered.