title: The use of SDS-PAGE scanning of spent dialysate to assess uraemic toxin removal by dialysis.
abstract: BACKGROUND
  Uraemic toxins in the 8 to 60 kDa molecular weight range have been attracting increasing attention in dialysis therapy. However, there are no available standardized methods to evaluate their removal. Using new filtering membranes, we evaluated SDS-PAGE of spent dialysate to assess cut-off ranges and removal capacities into dialysate, while also measuring classical markers of dialyser function.
  
  
  METHODS
  Eighteen dialysis patients were washed out for 2 weeks with FX 100 (Helixone(®)), followed by randomization to Xevonta Hi 23 (Amembris(®)) or FX dialysers for 2 weeks, then crossed over for an additional 2 weeks, and finally placed on Xenium 210 (Purema(®)) for 2 weeks. SDS-PAGE scanning of the removed proteins contained in the spent dialysate was performed during all dialysis sessions. Total mass of urea, creatinine, total proteins, beta 2 microglobulin (β2m), retinol-binding protein (RBP) and albumin were measured. The reduction rates of serum urea, creatinine, β2m, leptin, RBP, alpha 1-antitrypsin, albumin and total proteins were also determined.
  
  
  RESULTS
  SDS-PAGE scanning identified four major protein peaks (10-18, 20-22.5, 23-30 and 60-80 kDa molecular weight) and showed clear differences in the amounts of removed proteins between the dialysers, particularly in the 20-22.5, 23-30 and 60-80 kDa ranges. Total mass of removed β2m, RBP and albumin were in agreement with SDS-PAGE, while serum assays showed differing results.
  
  
  CONCLUSIONS
  SDS-PAGE scanning provided a good characterization of protein patterns in the spent dialysate; it extended and agreed with protein determinations and allowed a better assessment of dialyser performance in removing 10 to 80 kDa molecular weight substances. It also identified differences between the three mainly filtrating polysulfone dialysers that were not detected with blood measurements.
authors.affiliation: Division of Nephrology and Dialysis, Department of Medicine III, Medical University of Vienna, Vienna, Austria.
authors.forename: Alain
authors.initials: A
authors.lastname: Ficheux
authors.forename: Nathalie
authors.initials: N
authors.lastname: Gayrard
authors.forename: Ilan
authors.initials: I
authors.lastname: Szwarc
authors.forename: Daniel
authors.initials: D
authors.lastname: Andress
authors.forename: Stéphan
authors.initials: S
authors.lastname: Soullier
authors.forename: Yohan
authors.initials: Y
authors.lastname: Duny
authors.forename: Gilles
authors.initials: G
authors.lastname: Goubert
authors.forename: Marie
authors.initials: M
authors.lastname: Thomas
authors.forename: Johanna
authors.initials: J
authors.lastname: Bismuth-Mondolfo
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Daurès
authors.forename: Philippe
authors.initials: P
authors.lastname: Brunet
authors.forename: Marie-Françoise
authors.initials: MF
authors.lastname: Servel
authors.forename: Angel
authors.initials: A
authors.lastname: Argilés
mesh_terms: D000418:Albumins / Q000378:metabolism; D015314:Dialysis Solutions; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000628:therapy; D008970:Molecular Weight; D011485:Protein Binding; D011506:Proteins / Q000378:metabolism; D006435:Renal Dialysis; D012177:Retinol-Binding Proteins / Q000378:metabolism; D014118:Toxins, Biological / Q000378:metabolism*; D014511:Uremia / Q000097:blood; D001613:beta 2-Microglobulin / Q000097:blood
chemical_list: D000418:Albumins; D015314:Dialysis Solutions; D011506:Proteins; D012177:Retinol-Binding Proteins; D014118:Toxins, Biological; D001613:beta 2-Microglobulin