In vivo exposure to bicarbonate/lactate- and bicarbonate-buffered peritoneal dialysis fluids improves ex vivo peritoneal macrophage function

Abstract The impact on peritoneal macrophage (PMO) function of acidic lactate-buffered (Lac-PDF [PD4]; 40 mmol/L of lactate; pH 5.2) and neutral-pH, bicarbonate-buffered (TB; 38 mmol/L of bicarbonate; pH 7.3) and bicarbonate/lactate-buffered (TBL; 25 mmol/L of bicarbonate/15 mmol/L of lactate; pH 7.3) peritoneal dialysis fluids (PDFs) was compared during a study of continuous therapy with PD4, TB, or TBL. During a run-in phase of 6 weeks when all patients (n = 15) were treated with their regular dialysis regimen with Lac-PDF, median PMO tumor necrosis factor α (TNFα) release values were 203.6, 89.9, and 115.5 pg TNFα/10 6 PMO in the patients subsequently randomized to the PD4, TB, and TBL treatment groups, respectively. Median stimulated TNFα values (serum-treated zymosan [STZ], 10 μg/mL) were 1,894.6, 567.3, and 554.5 pg TNFα/10 6 PMO in the same groups, respectively. During the trial phase of 12 weeks, when the three groups of patients (n = 5 per group) were randomized to continuous treatment with PD4, TB, or TBL, median constitutive TNFα release values were 204.7, 131.4, and 155.4 pg TNFα/10 6 PMO, respectively. Stimulated TNFα values (STZ, 10 μg/mL) were 1,911, 1,832, and 1,378 pg TNFα/10 6 PMO in the same groups, respectively. Repeated-measures analysis of variance comparing the run-in phase with the trial phase showed that PMO TNFα release was significantly elevated in patients treated with both TB ( P = 0.040) and TBL ( P = 0.014) but not in patients treated with Lac-PDF ( P = 0.795). These data suggest that patients continuously exposed to bicarbonate- and bicarbonate/lactate-buffered PDFs might have better preserved PMO function and thus improved host defense status.