Interleukin-6 levels decrease in effluent from patients dialyzed with bicarbonate/lactate-based peritoneal dialysis solutions.

OBJECTIVE: Conventional lactate-buffered peritoneal dialysis (PD) solutions have several bioincompatible characteristics, including acidic pH, lactate buffer, and the presence of glucose degradation products (GDPs). These characteristics, along with inflammation, are believed to contribute to membrane dysfunction in peritoneal dialysis patients. A new PD solution containing a bicarbonate/lactate buffer system with physiologic pH and low GDPs has shown improved biocompatibility in both in vitro and ex vivo studies. In the present study, the concentrations of cytokines interleukin-6 (IL-6), tumor necrosis factor alpha (TNFalpha), and vascular endothelial growth factor (VEGF), were measured in timed overnight effluents from PD patients continuously dialyzed with either lactate-based control solution (C) or bicarbonate/lactate-based solution (B/L) for 6 months.

METHODS: Effluents from 92 continuous ambulatory peritoneal dialysis (CAPD) patients were collected when the patients were entered into the study (baseline, all patients on C for more than 3 months), and at 3 and 6 months following randomization to C (n = 31) or to B/L (n = 61). Effluent samples were filtered, stored frozen, and then assayed for IL-6, TNFalpha, and VEGF by ELISA.

RESULTS: A significant decrease in effluent IL-6 was seen at 3 months and at 6 months in the B/L-treated patients. Levels of VEGF were significantly reduced at 3 months. No changes in the levels of IL-6 or VEGF were seen in the C-treated patients, and no changes in TNFalpha were seen in either group over time.

CONCLUSIONS: Treatment with B/L is associated with decreased IL-6 synthesis and decreased VEGF secretion. The data suggest that the use of B/L solution is associated with reduced intraperitoneal inflammation and potential for angiogenesis. The use of B/L solution may, over time, help to restore peritoneal homeostasis and therefore preserve the function of the membrane in peritoneal dialysis.