Short-term effects of a new bicarbonate/lactate-buffered and conventional peritoneal dialysis fluid on peritoneal and systemic inflammation in CAPD patients: a randomized controlled study.

OBJECTIVES: This study was designed to compare the local peritoneal and systemic inflammatory effects of a conventional lactate-based (Lac) peritoneal dialysis (PD) solution and a new biocompatible bicarbonate/lactate-based (Bic/Lac) solution having low concentration of glucose degradation products.

METHODS: 26 stable, prevalent PD patients were enrolled in this prospective study. They sequentially underwent 3 months of therapy with the Lac solution and 3 months with the Bic/Lac solution in a randomized order. Flow cytometry was used to measure the expression of inflammatory molecules on peritoneal cells in overnight effluent collected at the end of each study period.

RESULTS: 21 patients successfully completed the study. Mean fluorescence intensity of human leukocyte antigen (HLA)-DR and CD14 expression by macrophages were not different between Lac and Bic/Lac. The peritoneal appearance rate of cancer antigen 125 (kU/minute) was 68 +/- 37 with Lac and 133 +/- 66 with Bic/Lac (p < 0.001), and of interleukin (IL)-6 (ng/minute), 0.28 +/- 0.2 with Lac and 0.18 +/- 0.16 with Bic/Lac (p = 0.014). HLA-DR macrophage expression and IL-6 peritoneal appearance rates did not correlate. Serum concentrations with Lac and Bic/Lac were, for IL-6, 3.49 +/- 2.28 and 3.72 +/- 2.46 ng/L (p = 0.17), and for high-sensitivity C-reactive protein, 2.31 +/- 2.98 and 2.71 +/- 3.31 mg/L (p = 0.32) respectively. The concentration of effluent macrophages (x10(6)/L) with Lac was 1.6 +/- 1.6 and with Bic/Lac 2.6 +/- 3.3 (p = 0.07).

CONCLUSIONS: We conclude that, although there was a significant reduction in peritoneal IL-6 in patients using Bic/Lac solution, systemic levels of inflammatory markers did not differ between the two solutions and no changes were present in macrophage surface activation markers, suggesting perhaps a less important role of peritoneal macrophages in the intraperitoneal chronic inflammatory process. The number of effluent macrophages tended to be higher in patients using the Bic/Lac solution, possibly contributing to improved intraperitoneal defense.