Human umbilical cord blood cell transplantation improves cardiac function in a myoardial infarction rat model but induces intestinal graft versus host disease.

Human umbilical cord blood cell (HUCBC) has low immunity. In the present study we investigated intestinal graft-versus-host disease (GVHD) induced by HUCBC transplantation in a myocardial infarction (MI) rat model. MI was established by using left anterior descending coronary artery (LAD) ligation. HUCBCs were injected into the animals 5 days post MI. Four weeks after the HUCBC transplantation, histology changes in small intestine were observed under an optical microscope. In addition, cardiac functions were tested. Further, factor VIII, vascular endothelial growth factor (VEGF) in the myocardium and small intestine were assayed. The HUCBC transplantation significantly induced intestinal GVHD in the MI rats. The HUCBC implantation remarkably improved ejection fraction (EF), fractional shortening (FS), and dp/dtmax in the MI rats (P<0.05). In the myocardium, the capillary density was larger in the small intestine of the HUCBC-transplanted rats compared to the controls. Real-time PCR and western blotting revealed that VEGF mRNA and protein levels in the myocardium and the small intestine dramatically significantly upregulated in the HUCBC-transplanted rats (P<0.05). The HUCBC transplantation significantly improves aggravated cardiac function of MI rats, but it induces intestinal GVHD.