Liver is not essential for solute transport during peritoneal dialysis

Abstract

Based on theoretical calculations on solute exchange capacities of various peritoneal tissues, the liver has been predicted to account for up to 43% of the permeability-surface area product (PS) of the entire peritoneal 'membrane' for a small solute (sucrose) during peritoneal dialysis (PD). In these calculations, the abdominal wall and the diaphragm were found to contribute only -10% to 15% of the total PS. However, evisceration has in previous studies been shown to affect the PS characteristics during PD only marginally (10 to 30%). In such evisceration experiments the liver was usually not removed, and therefore it has been suggested that an intact liver might have significantly contributed to the solute exchange under these premises. We assessed the peritoneal PS of 51Cr-EDTA (constantly infused intravenously) and the plasma-to-peritoneal clearance (Cl(B-P)) of 125I- human serum albumin (RISA) (given as an i.v. bolus) in Wistar rats during acute PD. In one group of rats the liver surface was sealed off using Histoacrylate glue (N = 6) and in another group a 90% hepatectomy was performed, the remaining portion of the liver, usually the right lower lobe, being sealed off by glue (N = 6). A third group was sham operated to serve as control (N = 12). The PS for 51Cr-EDTA was 0.32 ± 0.03 (± SE) ml · min-1 (N = 12) during control, 0.32 ± 0.04 ml · min-1 after 'sealing' of the liver surface (N = 6, P > 0.01) and 0.40 ± 0.03 after hepatectomy (N = 6, P > 0.1), that is, remained unchanged after experimental intervention. The Cl(B-P) of RISA control was 5.88 ± 1.0 μl · min-1 (N = 10), and was not altered after hepatectomy, 6.17 ± 0.48 μl · min-1 (N = 5, P > 0.1), but slightly increased after liver surface sealing (9.69 ± 1.09 μl · min-1, N = 5, P < 0.05). In conclusion, the present experiments indicate that the liver does not play and essential role in the overall solute exchange between the plasma and the peritoneal cavity (PC) during PD.