BACKGROUND: The most common complication after allogenic islet transplantation is rejection. This study was to evaluate the effect of anti-rejection of glucocorticoid-free immunosuppressive regimen on allogenic islet transplantation.
METHODS: Tacrolimus (FK506) +mycophenolate mofetil (MMF) and FK506+MMF+prednisone (Pred) were administered respectively for 2 weeks to inhibit rejection after allogenic islet transplantation in rats, which were compared with the control group. The concentrations of blood glucose, insulin and C-peptide were determined dynamically in recipients and the sites of transplantation were observed morphologically.
RESULTS: As compared with the control group without immunosuppressive agents, FK506+MMF and FK506+MMF+Pred could prolong the survival time of grafts significantly. There were many morphologically intact islets in the liver of recipients 2 months after transplantation. Group FK506+MMF kept normal levels of blood glucose, insulin and C-peptide beyond 60 days after transplantation. In contrast, group FK506+MMF+Pred secreted less C-peptide (P<0.05) and maintained a higher level of blood glucose concentration (P<0.01) after the operation. There was no significant difference in insulin concentrations between the two groups. The level of blood glucose beyond the first 2 weeks after drug withdrawal in group FK506+MMF+Pred decreased obviously (P<0.05), and the secretion of insulin and C-peptide increased. These results were compared with those the first 2 weeks after transplantation and the first 2 weeks after drug withdrawal.
CONCLUSIONS: Both regimens of FK506+MMF and FK506+MMF+Pred could provide effective immunosuppression. Moreover the combined glucocorticoid-free immunosuppressive strategy of low-dose FK506 and MMF could protect islet grafts in islet transplantation without diabetogenic side-effects.