Transplantation of human umbilical cord mesenchymal stem cells derived at different gestational weeks improves heart function in myocardial infarction models / 中国组织工程研究

ABSTRACT

BACKGROUND:Stem cels have multi-directional differentiation and self-replication abilities, under certain conditions, which can differentiate into myocardial cels to repair the damaged myocardium. OBJECTIVE: To investigate the effects of transplantation of umbilical cord mesenchymal stem cels derived at different gestational weeks on infarct size and angiogenesis in the infarct region of experimental rabbits with myocardial infarction. METHODS: Ten ful-term umbilical cord samples and 10 umbilical cord samples of aborted fetuses at 10-12 gestation weeks were selected to in vitro isolate umbilical cord mesenchymal stem cels that were subjected to BrdU labeling. HLA-G expression was detected in the cels. Thirty white rabbits were selected to make myocardial infarction models, and 2 weeks after modeling, the model rabbits were randomized into aborted cel transplantation group, ful-term cel transplantation group and control group (n=10 per group). Then, BrdU-labeled cels were injected correspondingly into the infarct region of rabbits in the two cel transplantation groups. Rabbits in the control group were subjected to an equal volume of serum-free. Four weeks after transplantation, heart function of rabbits was monitored using electrocardiogram, and myocardial tissues were taken to measure infarct size and blood capilary density. RESULTS AND CONCLUSION: HLA-G expression was different in different sources of umbilical cord mesenchymal stem cels high HLA-G expression was found in the aborted umbilical cord mesenchymal stem cels, and meanwhile, low HLA-G expression was found in the ful-term umbilical cord mesenchymal stem cels. Compared with the control group, the left ventricular end-diastolic volume and left ventricular ejection fraction of aborted and ful-term cel transplantation groups were significantly improved, especialy in the aborted cel transplantation group (P < 0.05). BrdU-positive cels were found in the infarct site in both transplantation groups. Compared with the control group, the infarct size and capilary density were improved most significantly in the aborted cel transplantation group folowed by the ful-term cel transplantation group (P < 0.05). Electrocardiogram findings showed significant improvement in both cel transplantation groups compared with the control group (P < 0.05), especialy in the aborted cel transplantation group. These findings indicate that umbilical cord mesenchymal stem cels derived at low gestational weeks improve the heart function more significantly than the ful-term umbilical cord mesenchymal stem cels, which have the potential to become a better source of cardiomyocytes for transplantation.