title: Short-term increase of glucose concentration in PDS results in extensive removal and high glycation level of vital proteins during continuous ambulatory peritoneal dialysis.
abstract: BACKGROUND
  The effect of clearance of so-called middle- and high-molecular weight proteins on clinical outcome of patients treated by peritoneal dialysis is still a matter of debate. In our present study, we investigated the impact of short-time alteration of the glucose concentration and the osmolarity of the peritoneal dialysis solution (PDS) on protein removal.
  
  
  METHODS
  Peritoneal dialysis liquids (PDL) were collected from 19 well-characterized continuous ambulatory peritoneal dialysis (CAPD) patients treated with two types of PDS: Baxter (n = 10) and Fresenius (n = 9). The patients were treated with two different glucose concentration of each PDS in 4-h cycles. The depletion of the six interfering high-abundant proteins from the PDL samples was performed with the Multiple Affinity Removal LC Column-Human 6. The resulting protein fractions were analysed by 2D gel electrophoresis, differential in gel electrophoresis, mass spectrometry and 2D western blot.
  
  
  RESULTS
  Proteomics investigation of the PDL fractions after depletion allowed the identification of 198 polypeptides of 424 excised spots. These polypeptides equates to 48 non-redundant proteins. Comparative analyses of 2D gel electrophoresis protein pattern revealed a clear correlation between protein removal and PDS glucose concentration and osmolarity. An increase for 4 h in the PDS osmolarity (with 43-51 mosmol/L) resulted qualitatively in 18-23% more protein removal in PDL. Moreover, 2D western blot analyses of the protein glycation pattern showed that the short-time increase in PDS glucose concentration (45-50 mM) resulted in significant alteration of the advanced glycosylation end products (AGEs) pattern.
  
  
  CONCLUSIONS
  The data presented in this study demonstrate a clear correlation between the short-time changes in glucose concentration and osmolarity of the PDS, and the augmentation of the protein removal and the appearance of AGEs during CAPD.
authors.affiliation: Department of Nephrology and Rheumatology, University Medical Centre, Georg-August-University Goettingen, Goettingen, Germany.
authors.forename: Ivana
authors.initials: I
authors.lastname: Pešić
authors.forename: Gry H
authors.initials: GH
authors.lastname: Dihazi
authors.forename: Gerhard A
authors.initials: GA
authors.lastname: Müller
authors.forename: Olaf
authors.initials: O
authors.lastname: Jahn
authors.forename: Moritz
authors.initials: M
authors.lastname: Hoffmann
authors.forename: Marwa
authors.initials: M
authors.lastname: Eltoweissy
authors.forename: Michael
authors.initials: M
authors.lastname: Koziolek
authors.forename: Hassan
authors.initials: H
authors.lastname: Dihazi
mesh_terms: D000328:Adult; D000368:Aged; D001692:Biological Transport; D015415:Biomarkers / Q000378:metabolism*; D015314:Dialysis Solutions / Q000737:chemistry*; D015180:Electrophoresis, Gel, Two-Dimensional; D005260:Female; D005500:Follow-Up Studies; D005947:Glucose / Q000378:metabolism*; D017127:Glycation End Products, Advanced / Q000378:metabolism*; D006031:Glycosylation; D006801:Humans; D007676:Kidney Failure, Chronic / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D009994:Osmolar Concentration; D010531:Peritoneal Dialysis, Continuous Ambulatory; D011379:Prognosis; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D015415:Biomarkers; D015314:Dialysis Solutions; D017127:Glycation End Products, Advanced; D005947:Glucose