title: Circulating levels and dietary intake of the advanced glycation end-product marker carboxymethyl lysine in chronic kidney disease patients on conservative predialysis therapy: a pilot study.
abstract: OBJECTIVE
  Advanced glycation end-products (AGEs) are proposed to influence inflammatory pathways and cardiovascular risk in chronic kidney disease (CKD). Dietary AGEs are believed to sustain circulating levels and toxicity in this condition.
  
  
  METHODS
  We investigated this aspect in a cross-sectional pilot study measuring levels of the AGE marker carboxymethyl lysine (CML) and fluorescent AGEs in the blood of pre-dialysis patients with CKD and hemodialysis (HD) patients (n = 10 each), and in a group of matched healthy controls (Ctr).
  
  
  METHODS
  Plasma CML was measured by immuno-dot blot and fluorescent AGEs were determined by high-performance liquid chromatography (HPLC) analysis measuring the fluorescence of the cross-link pentosidine. The dietary intake of CML was assessed by dietary recall to trace total AGE intake in patients with CKD and the Ctr group. All the subjects included in the study were assessed for dietary intake while maintaining their usual diet. Main exclusion criteria for patients with CKD and HD were severe protein-caloric malnutrition and inflammation (measured by high sensitivity C-reactive protein and interleukin-6 levels).
  
  
  RESULTS
  Plasma CML, as well as free and protein-bound fluorescent AGEs, significantly increased in CKD and even more in HD patients than that of the Ctr group. In patients with CKD, the average dietary intake of CML was less than half than that of the Ctr group (6 vs. 13 MU/day) and the lowered protein intake adopted spontaneously by these patients appear to explain this finding.
  
  
  CONCLUSIONS
  The results show that the intake of CML does not affect circulating levels of this as well as of other AGEs, in well nourished predialysis CKD patients.
authors.affiliation: Department of Internal Medicine, Laboratory of clinical biochemistry and nutrition, University of Perugia, Perugia, Italy.
authors.forename: Marta
authors.initials: M
authors.lastname: Piroddi
authors.forename: Ingrid
authors.initials: I
authors.lastname: Palazzetti
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Quintaliani
authors.forename: Francesca
authors.initials: F
authors.lastname: Pilolli
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Montaldi
authors.forename: Viola
authors.initials: V
authors.lastname: Valentina
authors.forename: Carmelo
authors.initials: C
authors.lastname: Libetta
authors.forename: Francesco
authors.initials: F
authors.lastname: Galli
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001120:Arginine / Q000031:analogs & derivatives / Q000097:blood; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000032:analysis / Q000378:metabolism; D016022:Case-Control Studies; D002851:Chromatography, High Pressure Liquid; D003430:Cross-Sectional Studies; D004032:Diet; D002149:Energy Intake; D005260:Female; D017127:Glycation End Products, Advanced / Q000008:administration & dosage / Q000097:blood / Q000378:metabolism*; D006801:Humans; D007249:Inflammation / Q000150:complications; D015850:Interleukin-6 / Q000097:blood; D007676:Kidney Failure, Chronic / Q000097:blood / Q000150:complications / Q000378:metabolism*; D008239:Lysine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood / Q000378:metabolism; D008297:Male; D044342:Malnutrition / Q000150:complications; D008875:Middle Aged; D015596:Nutrition Assessment; D010865:Pilot Projects; D012044:Regression Analysis; D006435:Renal Dialysis; D012307:Risk Factors
chemical_list: D015415:Biomarkers; D017127:Glycation End Products, Advanced; D015850:Interleukin-6; C048496:N(6)-carboxymethyllysine; D002097:C-Reactive Protein; D001120:Arginine; C062187:pentosidine; D008239:Lysine