Prevention of obesity-induced renal injury in male mice by DPP4 inhibition.

Therapies to prevent renal injury in obese hypertensive individuals are being actively sought due to the obesity epidemic arising from the Western diet (WD), which is high in fructose and fat. Recently, activation of the immune system and hyperuricemia, observed with high fructose intake, have been linked to the pathophysiology of hypertension and renal injury. Because dipeptidyl peptidase 4 (DPP4) is a driver of maladaptive T-cell/macrophage responses, renal-protective benefits of DPP4 inhibition in the WD-fed mice were examined. Mice fed a WD for 16 weeks were given the DPP4 inhibitor MK0626 in their diet beginning at 4 weeks of age. WD-fed mice were obese, hypertensive, and insulin-resistant and manifested proteinuria and increased plasma DPP4 activity and uric acid levels. WD-fed mice also had elevated kidney DPP4 activity and monocyte chemoattractant protein-1 and IL-12 levels and suppressed IL-10 levels in the kidney, suggesting macrophage-driven inflammation, glomerular and tubulointerstitial injury. WD-induced increases in DPP4 activation in the plasma and kidney and proteinuria in WD mice were abrogated by MK0626, although blood pressure and systemic insulin sensitivity were not improved. Contemporaneously, MK0626 reduced serum uric acid levels, renal oxidative stress, and IL-12 levels and increased IL-10 levels, suggesting that suppression of DPP4 activity leads to suppression of renal immune/inflammatory injury responses to a WD. Taken together, these results demonstrate that DPP4 inhibition prevents high-fructose/high-fat diet-induced glomerular and tubular injury independent of blood pressure/insulin sensitivity and offers a potentially novel therapy for diabetic and obesity-related kidney disease.