title: Comparison of Peritoneal Low-Molecular-Weight-Protein-Removal in CCPD and CAPD Patients Based on C-Terminal Agrin Fragment Clearance.
abstract: OBJECTIVE
  This study compares the peritoneal elimination of the low-molecular-weight-protein (LMWP) C-terminal agrin fragment (tCAF, size 22 kDa), a promising biomarker for kidney function, in continuous cycling peritoneal dialysis (CCPD) and continuous ambulatory peritoneal dialysis (CAPD).
  
  
  METHODS
  103 sets of serum, 24h-urine and dialysate samples were obtained in 15 CCPD (63 sets) and 11 CAPD (40 sets) patients. Total, renal and peritoneal substrate removals/clearances were measured/calculated for tCAF, creatinine, blood-urea-nitrogen (BUN), cystatin C and albumin and correlated with the peritoneal transport type.
  
  
  RESULTS
  Serum und urine concentrations of all biomarkers did not differ between both groups, urinary substrate removal was higher in CAPD patients for all biomarkers due to better residual renal function. Peritoneal substrate removal of tCAF and albumin were significantly higher in CAPD (tCAF: 35.3 vs. 19.3 µg/d, p<0.001; albumin: 4.3 vs. 3.7 g/d, p=0.001), whereas cystatin C and creatinine did not differ between CAPD and CCPD (cystatin: 7.7 vs. 6.1 mg/d, p=0.08, creatinine: 423.9 vs. 456.7 mg/d, p=0.241). BUN was better removed by CCPD (4846.6 vs. 3393.4 mg/d, p<0.001). CAPD patients with high-transporter characteristics had a higher peritoneal tCAF removal compared to high-average-transporters (49.8 vs. 28.4 µg/d, p<0.001), no differences could be detected in CCPD patients between these groups. CAPD patients using icodextrin twice/day had higher peritoneal clearance of tCAF compared to once daily (4.4 vs. 2.8 l/wk/1.73 m2 body-surface-area, p<0.001).
  
  
  CONCLUSIONS
  CAPD was superior to CCPD concerning peritoneal tCAF removal. This finding was pronounced in high-transporters and CAPD patients using icodextrin twice daily.
authors.affiliation: Abteilung fx00FC;r Nephrologie, Klinikum rechts der Isar, Mx00FC;nchen, Germany.
authors.forename: Dominik
authors.initials: D
authors.lastname: Steubl
authors.forename: Marcel
authors.initials: M
authors.lastname: Roos
authors.forename: Stefan
authors.initials: S
authors.lastname: Hettwer
authors.forename: Susanne
authors.initials: S
authors.lastname: Angermann
authors.forename: Ming
authors.initials: M
authors.lastname: Wen
authors.forename: Christoph
authors.initials: C
authors.lastname: Schmaderer
authors.forename: Peter
authors.initials: P
authors.lastname: Luppa
authors.forename: Uwe
authors.initials: U
authors.lastname: Heemann
authors.forename: Lutz
authors.initials: L
authors.lastname: Renders
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018171:Agrin / Q000097:blood* / Q000652:urine*; D005260:Female; D006801:Humans; D008297:Male; D008657:Metabolic Clearance Rate / Q000502:physiology*; D008875:Middle Aged; D010446:Peptide Fragments / Q000097:blood* / Q000652:urine*; D010531:Peritoneal Dialysis, Continuous Ambulatory / Q000379:methods*; D011446:Prospective Studies
chemical_list: D018171:Agrin; C000602450:C-terminal agrin fragment; D010446:Peptide Fragments