Dipeptidyl Peptidase IV Inhibition With MK0431 Improves Islet Graft Survival in Diabetic NOD Mice Partially via T-Cell Modulation

Abstract

OBJECTIVE—The endopeptidase dipeptidyl peptidase-IV (DPP-IV) has been shown to NH2-terminally truncate incretin hormones, glucose-dependent insulinotropic polypeptide, and glucagon-like peptide-1, thus ablating their ability to potentiate glucose-stimulated insulin secretion. Increasing the circulating levels of incretins through administration of DPP-IV inhibitors has therefore been introduced as a therapeutic approach for the treatment of type 2 diabetes. DPP-IV inhibitor treatment has also been shown to preserve islet mass in rodent models of type 1 diabetes. The current study was initiated to define the effects of the DPP-IV inhibitor sitagliptin (MK0431) on transplanted islet survival in nonobese diabetic (NOD) mice, an autoimmune type 1 diabetes model