IN-VITRO EFFECTS OF GLUCOSE POLYMER-CONTAINING PERITONEAL-DIALYSIS FLUIDS ON PHAGOCYTIC-ACTIVITY

Commercially available peritoneal dialysis fluids (PDFs) are known to impair peritoneal cellular defense mechanisms. We have investigated th e influence of glucose polymer-containing PDFs on phagocytic function in vitro. Polymorphonuclear neutrophils (PMNLs) and monocytes (MNs) fr om 10 continuous ambulatory peritoneal dialysis patients and 10 health y donors were incubated in PDFs containing either 7.5% icodextrin (glu cose polymer) or 1.5% glucose at original pH and pH 7.4. Chemiluminesc ence response and H2O2 production were measured following stimulation with preopsonized Staphylococcus epidermidis or phorbol myristate acet ate. Phagocytosis of radiolabeled bacteria and killing capacity of the cells were determined. A comparison of the impact of glucose polymer versus glucose-containing solutions at their original pH on the oxidat ive metabolism of the cells showed a highly significant difference (P < 0.0001) in favor of glucose polymers for H2O2 production of PMNLs (7 .78 +/- 4.5 nmol cytochrome C reduction/10(6) cells/min v 1.11 +/- 0.6 7 nmol cytochrome C reduction/10(6) cells/min) and MNs (7.66 +/- 3.6 n mol cytochrome C reduction/10(6) cells/min v 1.29 +/- 0.86 nmol cytoch rome C reduction/10(6) cells/min). Correspondingly, PMNLs and MNs incu bated in glucose polymers showed a significantly higher chemiluminesce nce response irrespective of the stimulant used (P < 0.0001). Applying the killing assay on PMNLs also revealed a significantly higher perce ntage of inactivated bacteria (45.5% +/- 11.0% v 29.2% +/- 15.5%; P < 0.05), After adjustment of pH to 7.4, a significant difference could o nly be found for H2O2 production of PMNLs in favor of glucose polymers (16.73 +/- 6.98 nmol cytochrome C reduction/10(6) cells/min v 11.65 /- 5.37 nmol cytochrome C reduction/10(6) cells/min; P < 0.05). In add ition, we compared the glucose-polymer solution to an otherwise equall y composed equiosmolar solution that contained 0.274% glucose instead of glucose polymers. No significant differences were detected with any of the tests applied. Our data suggest that glucose polymer solutions are comparatively less suppressive to phagocytic function than curren tly used glucose-containing PDFs. This effect may be attributed to the low osmolarity of these solutions. (C) 1997 by the National Kidney Fo undation, Inc.