Effect of combined cell transplantation of cardiomyocyte-like cells and endothelial progenitor cells on ventricular remodeling after acute myocardial infarction in rabbits

AIM: To compare the effect of combined cell transplantation of cardiomyocyte-like cells and endothelial progenitor cells with that of single-cell transplantation on the ventricular remodeling of rabbit acute myocardial infarction model. METHODS: Isolated mesenchymal stem cells (MSC) from the bone marrow of 24 rabbits were differentiated into cardiomyocyte-like cells and endothelial progenitor cells. Cell transplantation was performed 2 weeks after the establishment of acute myocardial infarction models. Rabbits were divided into control group, cardiomyocyte-like cell transplantation group, endothelial progenitor cell transplantation group and combined cell transplantation group. One hundred μl DMEM or cell suspension was injected into the border area of the myocardial infarction. Heart functions were assessed by transthoracic echocardiograph (TTC) before and 4 weeks after cell transplantation. Areas of infarction and constitution hydroxyproline were examined by TTC and chloraseptine oxidation method. RESULTS: MSCs induced by 5-AZA (5-azacytidine, 5-aza) and endothelial cell growth supplement (ECGS) from bovine pituitary were characterized by cardiomyocyte-like cells and endothelial progenitor cells. RT-PCR showed that the differentiated cells expressed atrial natriuretic polypeptide, phospholamban and myosin heavy chain mRNA. Endothelial progenitor cells showed a cobblestone shape when observed with phase-contrast microscope. CD133 significantly expressed and gradually descended in endothelial progenitor cells. Compared with control group, both combined cell transplantation and single cell transplantation ameliorated cardiac function and decreased the areas of infarction, plasma hydroxyproline or constitution hydroxyproline and MMP-9 (all P<0.05), but combined cell transplantation achieved better results than single cell transplantation. CONCLUSION: Our results show that MSCs can be differentiated into cardiomyocyte cells and endothelial progenitor cells in vitro. The effect of combined cell transplantation on ventricular remodeling of rabbit acute myocardial infarction model is superior to that of single cell transplantation.