Sun_2012_Diab.Vasc.Dis.Res_9_301

The present study was designed to identify the changes in microvesicle-dipeptidyl peptidase-IV DPP IV levels in human urine and serum and to determine whether there were correlations with the severity of diabetic kidney disease DKD A total of 127 patients with type 2 diabetes mellitus T2DM were divided into three groups according to the urinary albumin creatinine ratio UACR microalbuminuria group n 50 macroalbuminuria group n 34 and normoalbuminuria group n 43 and 34 age and sex-matched non-diabetic healthy subjects were selected as controls Microvesicle-bound DPP IV and free urinary DPP IV were separated by a filtra-centrifugation method The total microvesicles were captured by a specific monoclonal antibody AD-1 DPP IV activity was determined by measuring the cleavage of chromogenic free 4-nitroaniline from Gly-Pro-p-nitroanilide at 405 nm with an ELISA plate reader DPP IV protein levels were determined by ELISA and Western blot Our results showed that the microvesicle-bound type was the major form of DPP IV in urine the urinary microvesicle-DPP IV excretion of each T2DM group was significantly higher compared with controls The urinary microvesicle-DPP IV level was positively correlated with UACR in patients with T2DM These findings suggest that the urinary level of microvesicle-bound DPP IV is associated with the severity of DKD.