Supplementary Material for: Time-course Changes in Biomarker Levels Observed in Effluent of Patients Administered Bicarbonate/Lactate-Buffered Neutral-pH Peritoneal Dialysis Fluid

Abstract Introduction: Biomarker levels in peritoneal dialysis (PD) effluent can predict the risks of inflammation, wasting, atherosclerosis, encapsulating peritoneal sclerosis, and mortality. However, assessments of biomarker variations associated with different dwell times and buffered solutions have yielded inconsistent results. Methods: This prospective crossover study examined 10 patients on PD to investigate changes in effluent biomarkers during a retention period of 8 hours. Biomarker concentrations in bicarbonate lactate-buffered neutral-pH PD fluid (Bic/Lac PDF) effluent and those in lactate-buffered neutral-pH PD fluid (Lac PDF) effluent were compared. Results: Concentrations of urea nitrogen, creatinine, β2-microglobulin, and α1-microglobulin associated with Bic/Lac PDF and Lac PDF did not differ (analysis of variance [ANOVA]: p=0.62, 0.25, 0.73, and 0.95, respectively). Differences in cancer antigen 125, interleukin-6, fibrin degradation products (FDP), vascular endothelial growth factor (VEGF), and tumor necrosis factor-α (TNF-α) were not observed (ANOVA: p=0.81, 0.72, 0.66, 0.87, and 0.94, respectively). Additionally, concentrations of these biomarkers gradually increased over time from the start of PDF infusion until 8 hours later; however, in some cases, FDP, VEGF, and TNF-α concentrations in effluent were below detection limits at 2, 4, 6, and 8 hours. Conclusion: A protective effect of Bic/Lac PDF on the peritoneal membrane was not observed. Biomarker concentrations in PD effluent gradually increased over time; however, some were below the detection limits during 8 hours of retention. Assessments of biomarkers in effluent should be performed after an extended dwell time.