Inhibition of dipeptidyl peptidase IV protects tacrolimus-induced kidney injury

Accumulating evidence shows that a gut-released hormone, the glucagon-like peptide-1 (GLP-1), has not only a glucose-lowering effect but also a renoprotective effect against kidney injury. In this study, we investigated whether a dipeptidyl peptidase (DPP) IV inhibitor has a protective effect against tacrolimus-induced renal injury. Rats were treated with tacrolimus (1.5 mg/kg, subcutaneously) and the DPP IV inhibitor MK0626 (10 or 20 mg/kg, oral gavage) for 4 weeks. MK0626 treatment attenuated tacrolimus-induced renal dysfunction, tubulointerstitial fibrosis, and arteriolopathy. Moreover, these improvements were accompanied by a reduction in oxidative stress and apoptosis. MK0626 treatment increased the blood level of GLP-1 and the level of its receptor in tissue sections but did not alter the levels of other DPP IV substrates, such as neuropeptide Y and the stromal cell-derived factor-1. These data suggest that DPP IV inhibition has an important role in the renoprotection against tacrolimus-induced nephrotoxicity via antioxidative and antiapoptotic effects and preservation of the GLP-1 system.