EFFECTS OF PERITONEAL-DIALYSIS SOLUTIONS ON HEPATOCYTE METABOLISM

Peritoneal dialysis fluids (PDF) have toxic effects on cellular system s in vitro due to high concentrations of glucose and/or lactate. Mesot helial cells as well as cells of the host defence art-strongly suppres sed by low pH of PDE Liver cells are the most important system in regu lating metabolism. A great extent of PDF pass through the Liver. There fore, the aims of this study are to investigate the effects of differe nt glucose concentrations, of bicarbonate vs lactate as buffer substan ces and of pH on liver cell function. Cell integrity (LDH release) and metabolic activity Ch TIT) of HepG2 cells are determined. Incubation is performed between 24 and 48 hours at 37 degrees C with different PD F. Metabolites of intermediary metabolism are measured after 30 min in cubation with freshly isolated rat hepatocytes. The investigated PDF a re divided into three groups: Lactate-buffered low pH (A, B), bicarbon ate-buffered physiological pH (C, D) and lactate-buffered equalized wi th additional bicarbonate (E, F). 48-h incubation with pH neutralized solutions (E, F, C, D) reveal positive effects compared with acidic PD F (A, B respectively): LDH: E 16%, C 18% vs A 34%, B 33%. MTT: E 33%, C 26 vs A 3%, B 3%, data represent means, p <0.01. These effects are a lso seen in intermediary metabolism. Acidic PDF stimulate ketone body synthesis and shift redox equation to the reduction side. Already 24-h incubation shows significant lower metabolic activity by high glucose concentration (MTT: B 5% rig A 14%, P < 0.05). In contrast, effects w ith pH neutralized PDF are seen not till 48 hours (MTT: F 6% vs E 33%, p < 0.001). In conclusion data of in vitro investigation show positiv e effects of bicarbonate PDF on liver cells. Cell integrity and metabo lic activity are enhanced compared to cells incubated with acidic, lac tate-buffered solutions. High glucose concentrations diminish metaboli c activity.