The renoprotective effect of the dipeptidyl peptidase-4 inhibitor sitagliptin on adenine-induced kidney disease in rats.

We assessed the effect of treatment with the dipeptidyl peptidase-4 inhibitor, sitagliptin, on adenine-induced chronic kidney disease (CKD). Six equal groups of rats were given either normal food or food mixed with adenine (0.25% w/w for five weeks) to induce CKD. Some of these groups were also simultaneously treated with sitagliptin (2.5 and 10 mg/kg/day, by gavage). Rats given adenine showed elevation of blood pressure, decreased body weight and increased relative kidney weight. Adenine also significantly increased plasma urea, creatinine, cystatin C, liver-type fatty acid-binding protein concentrations and neutrophil gelatinase-associated lipocalin activity by 404%, 354%, 667%, 91% and 281% respectively and reduced plasma α-Klotho by 50%. In addition, adenine significantly increased albumin/creatinine ratio and N-acetyl-β-d-glucosaminidase activity by 3553% and 400% respectively and reduced creatinine clearance by 91%. Adenine feeding also significantly elevated the plasma concentration of inflammatory cytokines (plasma tumor necrosis factor-alpha, interleukin-1beta and transforming growth factor beta-1) and significantly reduced antioxidant indices (catalase, glutathione reductase and superoxide dismutase). Histopathologically, adenine caused renal fibrosis, inflammation and atrophy. When given concomitantly with adenine, sitagliptin ameliorated all the measured adenine-induced physiological and biochemical changes but not the histopathological changes. Sitagliptin (10 mg/kg/day) reduced plasma urea and creatinine by 32% and 25% respectively and increased creatinine clearance by 248%. These findings suggest a renoprotective action of sitagliptin on adenine-induced CKD.