Bicarbonate/lactate dialysis solution improves in vivo function of peritoneal host defense in rats.
OBJECTIVE
To assess the in vivo peritoneal inflammatory reaction in rats dialyzed with neutral, bicarbonate-lactate-buffered dialysis fluid.


METHODS
Chronic peritoneal dialysis was performed for 4 weeks in Wistar rats with two solutions: (1) 40 mmol/L lactate-buffered fluid, pH 5.2, with a glucose concentration of 2.27 g/dL (Lac); and, (2) 15 mmol/L lactate and 25 mmol/L bicarbonate-buffered fluid, pH 7.0-7.5, with a glucose concentration of 2.27 g/dL (Bic-Lac). After 4 weeks, two peritoneal equilibration tests (PET 1 and PET 2) were performed in all animals with each respective solution. PET 1 was done with test solutions alone, whereas, on a subsequent day, PET 2 was performed with test solutions supplemented with endotoxin [lipopolysaccharide (LPS)] to induce peritonitis.


RESULTS
During PET 1 no consistent differences were detected in peritoneal permeability between the Lac and Bic-Lac groups. Total dialysate cell count in the Bic-Lac animals was lower than in rats treated with Lac fluid: that is, at 8 hours, the respective counts were 1858+/-524 cells/microL versus 2785+/-1162 cells/microL (p < 0.01). Dialysate from animals dialyzed with Bic-Lac contained more macrophages (at 4 hours: 53.6%+/-35.8% versus 35.8%+/-8.8%, p < 0.001) and fewer neutrophils (at 4 hours: 3.6%+/-1.8% versus 15.4%+/-6.1%, p < 0.001) as compared to those dialyzed with the Lac solution. Concentration of nitrites in 8-hour dwell dialysate samples from Bic-Lac rats was lower than that in the Lac group (0.98+/-0.28 micromol/mL versus 2.32+/-0.87 micromol/mL, p < 0.002), but cytokine levels in the dialysates were comparable. During PET 2, the increase in peritoneal permeability resulting from the LPS-induced inflammatory response was similar for both test solutions. Dialysate cell count was higher in the Lac group versus the Bic-Lac group (at 8 hours: 8789+/-4862 cells/microL versus 3961+/-581 cells/microL, p < 0.001), contained more neutrophils (at 8 hours: 80.0%+/-11.3% versus 54.8%+/-4.4%, p < 0.001) and fewer macrophages (at 8 hours: 6.8%+/-5.6% versus 21.2%+/-3.3%, p < 0.05). During peritonitis, we found a higher overall dialysate concentration of both tumor necrosis factor (TNFalpha: +53%, p < 0.05) and of interferon gamma (IFN-gamma: +303%, p < 0.02), in the Bic-Lac group than in the Lac group.


CONCLUSIONS
A lower dialysate cell count, higher percentage of macrophages, and lower percentage of neutrophils in dialysate suggest that Bic-Lac fluid induces a diminished nonspecific inflammatory response of the peritoneal cavity during dialysis. However, after in vivo stimulation, peritoneal cells from animals dialyzed with Bic-Lac solution possess an augmented ability to produce inflammatory cytokines.
Pawlaczyk
K
K
Department of Pathophysiology, Poznan Medical School, Poland.
Kuzlan-Pawlaczyk
M
M
Wieczorowska-Tobis
K
K
Polubinska
A
A
Wisniewska
J
J
Faict
D
D
Holmes
C J
CJ
Breborowicz
A
A
D000818:Animals; D001639:Bicarbonates / Q000494:pharmacology*; D002452:Cell Count; D003404:Creatinine / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism; D015314:Dialysis Solutions / Q000737:chemistry* / Q000494:pharmacology*; D005947:Glucose / Q000378:metabolism; D018836:Inflammation Mediators / Q000378:metabolism; D019344:Lactic Acid / Q000494:pharmacology*; D008070:Lipopolysaccharides; D008264:Macrophages / Q000166:cytology; D008297:Male; D009504:Neutrophils / Q000166:cytology; D009573:Nitrites / Q000378:metabolism; D010530:Peritoneal Dialysis; D010537:Peritoneum / Q000166:cytology / Q000378:metabolism*; D010538:Peritonitis / Q000209:etiology / Q000378:metabolism*; D010539:Permeability; D011506:Proteins / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
D001639:Bicarbonates; D016207:Cytokines; D015314:Dialysis Solutions; D018836:Inflammation Mediators; D008070:Lipopolysaccharides; D009573:Nitrites; D011506:Proteins; D019344:Lactic Acid; D003404:Creatinine; D005947:Glucose