Systemic and intraperitoneal proinflammatory cytokines profiles in patients on chronic peritoneal dialysis

Cytokines are essential mediators of immune response and inflammatory reactions. Patients with chronic renal failure and on Continuous Ambulatory Peritoneal Dialysis commonly present abnormalities of immune function related to impaired kidney function, accumulation of uremic toxins and bioincompatibility of peritoneal dialysis solutions. Aim of this study was to examine effects of the CAPD solutions (standard v.s. biocompatible), as well as dialysis duration upon the local and systemic profile of the pro-inflammatory cytokines (IL-1, TNF and IL-6) in patients on CAPD. The cross-sectional study included 44 CAPD patients (27 M and 17 F, average mean age 57.12+/-16.66), of whom 21 patients were on the standard solutions (A.N.D.Y.Disc) for peritoneal dialysis and 23 on the biocompatible solutions (Gambrosol bio trio, Stay Safe balance). The average dialysis treatment period was 3.59+/-2.67 years. In all CAPD patients dialysed longer than 6 months, levels of IL-1. TNF and IL-6 in the serum and dialysis effluent were analysed in the phase without acute infection-related complications (CAPD peritonitis, infection of the catheter exit-site, other acute infections). The control group included 20 patients with the CRF (stage IV and V) whose serum levels of the examined cytokines were also determined. Levels of the inflammatory cytokines were measured by commercial specific ELISA kits (BioSource, Camarillo, California, USA). Statistical analysis of the obtained results was performed by commercial statistics PC software (Stat for Windows, R.4.5. SAD). The serum IL-1 and IL-6 levels were not statistically significantly different in patients on CAPD, irrespective of the type of the used dialysis solutions and in the control group of patients with CRF. The serum TNF levels, unlike IL-1 and IL-6, were statistically significantly higher in patients on CAPD in comparison with the control group of patients (13.203.23 v.s. 5.594.54, p< 0.001, Mann Whitney test). The serum and effluent IL-1 levels in patients on CAPD within one and longer than one year of dialysation did not significantly differ, but the effluent IL-6 levels were significantly higher than in the serum of both groups of patients, that is, effluent IL-6 levels in CAPD patients dialysed more than one year was significantly higher in comparison with those in patients dialysed within a year. Both serum and intraperitoneal levels of the examined cytokines did not significantly differ in patients on the standard and biocompatible solutions, regardless of the present trend toward decrease of intraperitoneal IL-6 levels in patients on biocompatible solutions. Residual renal funcion and number of CAPD peritonitis did not have any important impact upon the serum and IP levels of the examined ctokynes. Elevated serum TNF levels and significant local IL-6 production in our CAPD patients indirectly confirm importance of peritoneal dialysis in amplification of the chronic inflammation substantially depend on the duration of dialysis treatment.