Background: Cell transplantation offers the promise in the restoration of cardiac function after myocardial infarction. We investigate the therapeutic potential of human umbilical cord derived stem (UCDS) cells in a rat myocardial infarction model.
Methods: Two weeks after induction of myocardial infarction, the surviving rats with left ventricular ejection fraction less than 60% were randomly divided into a phosphate-buffered saline control group and a UCDS cell treated group. Cardiac function was assessed by echocardiography 2 weeks and 4 weeks after cell transplantation. Histologic study and immunofluorescence were performed to investigate differentiation of transplanted cells, capillary and arteriole density, secretion of cytokines, and cardiomyocytes apoptosis.
Results: A statistically significant improvement of cardiac function was observed in the experimental group of rats compared with the control group. Four weeks after transplantation, histologic examination revealed that some of the transplanted UCDS cells survived in the infarcted myocardium and accumulated around arterioles and scattered in capillary networks. We observed some of the cells expressed cardiac troponin-T, von Willebrand factor, and smooth muscle actin, indicating regeneration of damaged myocardium by cardiomyocytic, endothelial, and smooth muscle differentiation of UCDS cells in the infarcted myocardium. The capillary and arteriole density were also markedly increased in the UCDS-cell-treated group. In addition, the apoptotic cells were decreased significantly compared with the phosphate-buffered saline controls.
Conclusions: Our findings demonstrate that transplanted UCDS cells provide benefit in cardiac function recovery after acute myocardial infarction in rats, suggesting UCDS cells represent a promising cell source for future routine cell therapy applications.