Comparison of Peritoneal Low-Molecular-Weight-Protein-Removal in CCPD and CAPD Patients Based on C-Terminal Agrin Fragment Clearance

Abstract Background/Aims: 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