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.