title: Increased plasma dipeptidyl peptidase-4 activities are associated with high prevalence of diabetic nephropathy in Chinese patients with newly diagnosed type 2 diabetes: A cross-sectional study.
abstract: OBJECTIVE
  To investigate the association between plasma Dipeptidyl peptidase-4 (DPP4) activities and diabetic nephropathy in type 2 diabetes.
  
  
  METHODS
  A total of 1193 newly diagnosed type 2 diabetic subjects were studied. Plasma DPP4 activity, mannose 6-phosphate receptor, inflammatory markers and oxidative stress parameters were measured in all participants. Diabetic nephropathy was defined as the presence of albuminuria or an estimated glomerular filtration rate < 60 mL/min/1.73 m(2).
  
  
  RESULTS
  Participants in the highest quartile of DPP4 activity had higher HbA1c, homeostatic model assessment of insulin resistance, nitrotyrosine, 8-iso-PGF2a, interleukin-6, high-sensitivity C-reactive protein, mannose 6-phosphate receptor, urinary albumin-to-creatinine ratio and lower estimated glomerular filtration rate compared with participants in the lowest quartile (all p < 0.001). DPP4 activities were associated positively with HbA1c, homeostatic model assessment of insulin resistance, nitrotyrosine, 8-iso-PGF2a, interleukin-6, high-sensitivity C-reactive protein, mannose 6-phosphate receptor, urinary albumin-to-creatinine ratio and negatively with estimated glomerular filtration rate (all p < 0.001). In the highest DPP4 quartile, diabetic nephropathy risk was significantly higher (odds ratio: 3.77; 95% confidence interval: 2.34-6.07) than in the lowest quartile after adjustment for potential confounders. This association remained strong (2.85; 1.74-4.68) after further controlling for HbA1c, homeostatic model assessment of insulin resistance, nitrotyrosine and high-sensitivity C-reactive protein.
  
  
  CONCLUSIONS
  This study shows that increased DPP4 activities are strongly and independently associated with diabetic nephropathy in type 2 diabetes. The associations between DPP4 and diabetic nephropathy, although strong, do not imply causality. There are however plausible mechanisms which could explain such a link.
authors.affiliation: Department of Endocrinology and Metabolism, Affiliated Hospital of Guilin Medical University, Guilin, P.R. China Center of Diabetic Systems Medicine, Guilin Medical University, Guilin, P.R. China.
authors.forename: Tianpeng
authors.initials: T
authors.lastname: Zheng
authors.affiliation: Diabetic Centre of Control and Prevention, The People's Liberation Army 520 Hospital, Mianyang, P.R. China.
authors.forename: Yihong
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Medical Examination Center, Affiliated Hospital of Guilin Medical University, Guilin, P.R. China dcqinshenghua@126.com.
authors.forename: Shenghua
authors.initials: S
authors.lastname: Qin
authors.affiliation: Department of Laboratory Medicine, Affiliated Hospital of Guilin Medical University, Guilin, P.R. China.
authors.forename: Hongbo
authors.initials: H
authors.lastname: Liu
authors.affiliation: Center of Diabetic Systems Medicine, Guilin Medical University, Guilin, P.R. China.
authors.forename: Xiaoxi
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Center of Diabetic Systems Medicine, Guilin Medical University, Guilin, P.R. China.
authors.forename: Hailu
authors.initials: H
authors.lastname: Zhao
mesh_terms: D000328:Adult; D000368:Aged; D000419:Albuminuria / Q000175:diagnosis; D044466:Asian People; D015415:Biomarkers / Q000097:blood*; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000453:epidemiology*; D003928:Diabetic Nephropathies / Q000150:complications* / Q000453:epidemiology*; D018819:Dipeptidyl Peptidase 4 / Q000378:metabolism*; D005260:Female; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012307:Risk Factors
chemical_list: D015415:Biomarkers; C042807:DPP4 protein, human; D018819:Dipeptidyl Peptidase 4
keywords: DPP4 activity; diabetic nephropathy; inflammation; insulin resistance; oxidative stress