Glucose homeostasis changes and pancreatic β-cell proliferation after switching to cyclosporin in tacrolimus-induced diabetes mellitus.

BACKGROUND Switching to cyclosporine A may result in a reversion of tacrolimus-induced diabetes mellitus. However, mechanisms underlying such a reversion are still unknown. METHODS Obese Zucker rats were used as a model for tacrolimus-induced diabetes mellitus. A cohort of 44 obese Zucker rats received tacrolimus for 11 days (0.3mg/kg/day) until diabetes development; then: (a)22 rats were euthanized at day 12 and were used as a reference group (tacrolimus-day 12), and (b)22 rats on tacrolimus were shifted to cyclosporin (2.5mg/kg/day) for 5 days (tacrolimus-cyclosporin). An additional cohort of 22 obese Zucker rats received the vehicle for 17 days and were used as a control group. All animals underwent an intraperitoneal glucose tolerance test at the end of the study. RESULTS β-cell proliferation, apoptosis and Ins2 gene expression were evaluated. Compared to rats in tacrolimus-day 12 group, those in tacrolimus-cyclosporin group showed a significant improvement in blood glucose levels in all assessment points in intraperitoneal glucose tolerance test. Diabetes decreased from 100% in tacrolimus-day 12 group to 50% in tacrolimus-cyclosporin group. Compared to tacrolimus-day 12 group, rats in tacrolimus-cyclosporin group showed an increased β-cell proliferation, but such an increase was lower than in rats receiving the vehicle. Ins2 gene expressions in rats receiving tacrolimus-cyclosporin and rats receiving the vehicle were comparable. CONCLUSION An early switch from tacrolimus to cyclosporin in tacrolimus-induced diabetes mellitus resulted in an increased β-cell proliferation and reversion of diabetes in 50% of cases.