The Influence Of Cardiac Differentiation And Enrichment On Tumorigenesis Of Embryonic Stem Cells Transplantation In Infarcted Heart

objective:The therapeutic potential of embryonic stem cells(ESCs) in ischemic heart disease has been widely recognized. However, teratoma formation after ESCs transplantation interferes the clinical application of ESCs. This study analyzed the influence of cardiac differentiation and enrichment on the tumor formation of mouse ESCs(mESCs) after tran- splantation into infarcted hearts of rats.Methods:Undifferentiated mESCs were expanded in the presence of leukemia inhibitory factor(LIF). mESCs were cultured in a slow turning lateral vessel(STLV) for mass production of embryoid bodies(EBs). The EBs were induced to differentiate into cardiomyocytes(ES-CMs) with ascorbic acid. Cardiomyocytes derived from ESCs were then enriched by Percoll density gradient centrifugation(ES-CM-PDGC). RT-PCR for Oct-4 were used to detect undifferentiated ESCs. There were three groups according to the differentiation and enrichment of ESCs: undifferentiated ESCs, ES-CMs, ES-CM-PDGC. Every group included 15 rats. Abuout 5×10~6 cells were transplantated into the infarcted hearts of immunosuppressive rats. Eight weeks after transplantation, hearts were extracted for teratoma detection. Statistics analysis used to compare the tumor incidence and volume in different groups.Results: Undifferented ESCs were detected in ES-CMs, but they were not detected in ES-CM-PDGC. Teratoma was observed in both mESCs and ES-CMs groups. However, no teratoma was detected in ES-CM-PDGC group. The incidence of teratoma were about 80%(12+/3-) and 33.33%(5+/10-) in mESCs group and ES-CMs group respectively. The average of the tumor volume in mESCs group and ES-CMs group were about 82.72mm~3 and 50.50mm~3 respectively. Statistics analysis showed that the tumor incidence and tumor volume of ES-CMs group was significantly lower than those of the mESCs group, and that the tumor incidence in ES-CM-PDGC group was significantly lower than that of the ES-CMs group.Conlusion:The tumorigenicity of mESCs decreased after cardiac defferentiation. Enriched cardiomyocytes derived from mESCs don't form teratoma in infarcted hearts.