Bicarbonate-buffered CAPD solutions preserve granulocyte function.

The currently available lactate-based dialysate solutions (LBDS) have an unphysiological composition and are known for their poor biocompatibility. This review summarizes recent data about the effect of bicarbonate-buffered CAPD solutions (BEDS) on granulocyte function. LBDS produces a severe and long-lasting intracellular acidosis that is not readily reversible with elevation of extracellular pH. Intracellular calcium release, chemotaxis, phagocytosis, and superoxide production are nullified by acidic LBDS, while actin polymerisation is markedly blunted. In contrast, BEDS at low glucose concentrations (1,5%) elicits physiological cell responses comparable to Hank's buffer for intracellular pH, actin polymerisation, calcium release, superoxide production and phagocytosis. Chemotaxis is reduced to 60% of control. If an acidic pH with it's marked toxicity is avoided, it becomes obvious that increasing glucose concentrations inhibit cell functions in a dose-dependent manner. Compared with lactate-based CAPD solutions, bicarbonate-buffered dialysate was shown to improve every neutrophil function parameter tested. In addition, bicarbonate was superior to lactate-based solutions even if their pH was neutralized or if spent dialysate was added to fresh dialysate, simulating intraabdominal pooling of spent fluid.