Free choline and phospholipid-bound choline concentrations in serum and dialysate during peritoneal dialysis in children and adults

Objectives: This study tested whether continuous ambulatory peritoneal dialysis (CAPD) changes free or phospholipid-bound choline concentrations in serum or peritoneal dialysis fluid of patients with end stage renal disease (ESRD). Design and methods: Serum and dialysate choline and phospholipid-bound choline were measured before, during and after 6 h CAPD. Results: Serum choline concentrations were higher in patients with ESRD compared with age-matched controls. CAPD lowered serum choline concentrations significantly although it did not influence phospholipid-bound choline. Choline accumulated in the dialysate, reaching 28.4 ± 2.7 μM in children and 18.2 ± 1.4 μM in adults, during six hours CAPD; phospholipid-bound choline increased to 22.9 ± 2.5 μM and 10.8 ± 1.4 μM in children and adults, respectively. The total daily loss of choline into the dialysate was 181 ± 20 μmoles in children and 260 ± 18 μmoles in adults. Conclusion: CAPD causes a substantial loss of choline into peritoneal dialysates and reduces serum choline concentrations significantly.