Generation of TNFα and interleukin-6 by peritoneal macrophages after overnight dwells with bicarbonate- or lactate-buffered dialysis fluid

Abstract

Objective: In order to evaluate the biocompatibility profile of a newly designed peritoneal dialysis fluid (PDF), we evaluated peritoneal leukocyte (PMΦ) cytokine release following overnight in vivo dwells using standard, lactate-buffered, single-chamber bag PDF (Lac-PDF) and purely bicarbonate-buffered, double-chamber bag PDF containing 34 (Bic-PDF) or 39 (Bic Hi-PDF) mmol/L bicarbonate. Design: A randomized, open, crossover clinical trial with single weekly test dwells was performed in stable, long-term continuous ambulatory PD patients (n = 8). During 8-hour overnight dwells, PMΦ were exposed to different PDF containing 1.5% glucose. After drainage, peritoneal cells were isolated and incubated with RPMI 1640 medium for 2 or 3 hours, with and without stimulation by lipopolysaccharide (LPS). Ex vivo release of tumor necrosis factor (TNF)-α and interleukin (IL)-6 was measured by specific ELISA technique. Results: After pre-exposure to Lac-PDF, PMΦ generated 242 ± 279 pg TNFα/106 cells and 157 ± 105 pg IL-6/106 cells. When pre-exposed to Bic-PDF and Bic Hi-PDF, TNFα and IL-6 production of PMΦ was not significantly different from Lac-PDF. After LPS stimulation (100 ng/mL), PMΦ secretion of TNFα and IL-6 pre-exposed to three PDF revealed no significant differences between groups: TNFα was 2864 ± 1216, 2910 ± 1202, and 3291 ± 558 pg/106 cells after overnight dwells with Lac-PDF, Bic-PDF, and Bic Hi-PDF, respectively. Comparably, LPS-stimulated (100 pg/mL) PMΦ showed IL-6 secretion of 891 ± 335, 1380 ± 1149, and 1442 ± 966 pg/106 cells for Lac-PDF, Bic-PDF, and Bic Hi-PDF. Conclusion: After long-term overnight dwells, initial pH, the different buffers, and varying glucose degradation product levels of PDF do not strongly affect PMΦ function with respect to cytokine release. The lack of significant differences between fluids may result from the complete dialysate equilibration achieved during the overnight intraperitoneal dwell.