title: The determination of AGE-peptides by flow injection assay, a practical marker of diabetic nephropathy.
abstract: BACKGROUND
  Increasing evidence has suggested that advanced glycation end products (AGEs) might play a central role in the pathogenesis of diabetic complications. Serum AGEs concentration may serve as a useful marker for monitoring pathological processes and progression of diabetic complications.
  
  
  METHODS
  A flow injection assay (FIA) system was developed using high performance liquid chromatography (HPLC) to detect low molecular mass AGEs (AGE-peptides, AGE-P). Serum from diabetic patients (n=126), normal controls (n=54) and diabetic mice (n=20) and matched controls (n=20) were collected.
  
  
  RESULTS
  The coefficient of variance for intra-assay and inter-assay were 1.2% and 6.3%, respectively. The range of recoveries was 94.9-101.9%. The serum AGE-P concentration was significantly increased both in diabetic patients (2.976+/-0.247 vs. 1.385+/-0.131 U/ml, P<0.0001) and mice (6.71+/-0.50 vs. 2.49+/-0.10 U/ml, P<0.0001) than their respective controls. Concentration of AGE-P was positively correlated with serum creatinine (Scr) (r=0.7133, P<0.0001), 24-h urinary protein (24-h UPro) (r=0.8704, P<0.0001) and urinary albumin excretion (UAE) (r=0.5989, P<0.0001).
  
  
  CONCLUSIONS
  The present study suggested that FIA might be a reliable method for measuring the serum AGE-P. Furthermore, our results supported the notion that AGE-P might be a valuable marker for predicting the severity of diabetic nephropathy (DN).
authors.affiliation: Division of Endocrinology, ZhongDa Hospital, Southeast University, 210009, Nanjing, China. szl@public1.ptt.js.cn
authors.forename: S
authors.initials: S
authors.lastname: Zilin
authors.forename: L
authors.initials: L
authors.lastname: Naifeng
authors.forename: L
authors.initials: L
authors.lastname: Bicheng
authors.forename: W
authors.initials: W
authors.lastname: Jiping
mesh_terms: D000818:Animals; D015415:Biomarkers; D002138:Calibration; D016022:Case-Control Studies; D002851:Chromatography, High Pressure Liquid; D003401:Creatine / Q000097:blood; D003928:Diabetic Nephropathies / Q000175:diagnosis*; D017022:Flow Injection Analysis / Q000379:methods*; D017127:Glycation End Products, Advanced / Q000097:blood / Q000737:chemistry*; D006801:Humans; D051379:Mice; D008875:Middle Aged; D010455:Peptides / Q000097:blood*; D015203:Reproducibility of Results; D013050:Spectrometry, Fluorescence
chemical_list: D015415:Biomarkers; D017127:Glycation End Products, Advanced; D010455:Peptides; D003401:Creatine