Systemic and intraperitoneal proinflammatory cytokine profiles in patients on continuous ambulatory peritoneal dialysis.

Our cross-sectional study included 44 patients (27 men, 17 women; mean age: 57.12 +/- 16.66 years; mean dialysis treatment period: 3.59 +/- 2.67 years) on continuous ambulatory peritoneal dialysis (CAPD). Of the 44 patients, 21 were using standard solutions (Stay*Safe, ANDY-disc: Fresenius Medical Care, Bad Homburg, Germany), and 23 were using biocompatible solutions (Gambrosol Trio: Gambro Lundia AB, Lund, Sweden; Stay*Safe Balance: Fresenius Medical Care). In all CAPD patients dialyzed longer than 6 months, we analyzed levels of interleukin 1beta (IL-1beta), tumor necrosis factor alpha (TNFalpha), and interleukin 6 (IL-6) in serum and dialysis effluent when patients were free of acute infection-related (CAPD peritonitis, exit-site infection, other acute infections) complications. In a control group of 20 patients with chronic renal failure [CRF (stages IV and V)], we also determined serum levels of the same cytokines. Levels of the inflammatory cytokines were measured using specific commercial ELISA kits (BioSource, Camarillo, CA, U.S.A.). Statistical analysis of the results was performed using commercial statistics software for the PC (Statistica for Windows, rev. 4.5: StatSoft, Tulsa, OK, U.S.A.). Serum levels of LL-1beta and IL-6 were not statistically significantly different between the patients on CAPD, regardless of the type of dialysis the used, and between the patients and the control group with CRF. Serum levels of TNFalpha, unlike those for IL-1beta and IL-6, were statistically significantly higher in patients on CAPD than in the control group with CRF (13.20 +/- 3.23 pg/mL vs. 5.59 +/- 4.54 pg/mL, p < 0.001, Mann-Whitney test). Serum and effluent IL-1beta levels in patients on CAPD for less than 1 year and more than 1 year did not significantly differ, but effluent IL-6 levels were significantly higher than serum IL-6 levels in both groups of patients, and effluent IL-6 levels were significantly higher in CAPD patients dialyzed for more than 1 year than in patients dialyzed for less than 1 year. Serum and intraperitoneal (IP) levels of the examined cytokines did not significantly differ in patients on standard and biocompatible solutions, but a trend toward lower IP levels of IL-6 was seen in patients on biocompatible solutions. Residual renal function and number of episodes of CAPD peritonitis had no important effect on serum and IP levels of the examined cytokines. Elevated serum levels of TNFalpha and significant local IL-6 production in our CAPD patients indirectly confirmed the importance of peritoneal dialysis (PD) in amplifying the chronic inflammation that substantially depends on duration of dialysis treatment.