Dipeptidyl peptidase-IV is a potential molecular biomarker in diabetic kidney disease

• Published in: Diabetes & vascular disease research Vol. 9; no. 4; pp. 301 - 308
• Main Authors: Sun, Ai-li, Deng, Jing-ti, Guan, Guang-ju, Chen, Shi-hong, Liu, Yuan-tao, Cheng, Jing, Li, Zhen-wei, Zhuang, Xiang-hua, Sun, Fu-dun, Deng, Hao-ping
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01.10.2012
• Subjects: Aged; Albuminuria - diagnosis; Albuminuria - enzymology; Albuminuria - etiology; Albuminuria - urine; Biomarkers - blood; Biomarkers - urine; Blotting, Western; Case-Control Studies; Centrifugation; Creatinine - urine; Diabetes Mellitus, Type 2 - complications; Diabetic Nephropathies - blood; Diabetic Nephropathies - diagnosis; Diabetic Nephropathies - enzymology; Diabetic Nephropathies - etiology; Diabetic Nephropathies - urine; Dipeptidyl Peptidase 4 - blood; Dipeptidyl Peptidase 4 - urine; Enzyme-Linked Immunosorbent Assay; Exosomes - enzymology; Exosomes - ultrastructure; Female; Humans; Kidney Function Tests; Linear Models; Male; Microscopy, Electron; Middle Aged; Predictive Value of Tests; Severity of Illness Index; Urinalysis; Urine - chemistry; Urine - cytology; albuminuria; urinary microvesicles; dipeptidyl peptidase-IV; Diabetic kidney disease
• DOI: 10.1177/1479164111434318
• ISSN: 1479-1641; 1752-8984

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.