Kinetics and dose response of the effects of heated glucose peritoneal dialysis fluids on the respiratory burst of rat peritoneal leukocytes

Heat sterilization of glucose containing peritoneal dialysis (PD) fluids induces the production of cytotoxic glucose degradation products (CDPs), some of which are still unidentified. The present study was performed to characterize the kinetics and the dose-response of the respiratory burst inhibition of CDPs and to compare different fluids in this respect. The zymosan-induced respiratory burst of rat peritoneal neutrophils and macrophages was measured by chemiluminescence (CL) after incubation in vitro for 1, 2, and 4 hours in different homemade and commercially available PD fluids, followed by one hour of recovery in Hanks' buffer. Heat sterilized fluids were compared with their filter sterilized equivalents at two different pH levels. The results revealed that the inhibitory effect of heat sterilized fluids on the respiratory burst of peritoneal neutrophils is additive to that of low pH, but more fast-acting and, in contrast to the pH effect, similar in magnitude to its in vivo equivalent. The effect developed within 1 hour and had a linear dose response. The low CDP fluid Gambrosol-Bio was less toxic than the conventional fluid Gambrosol, but the difference was smaller than expected in relation to measured concentrations of known GDPs. Macrophages were less sensitive than neutrophils to the CDP effect.