Markers of inflammation and oxidative stress in peritoneal dialysis: a comparison between high and low peritoneal transporters

Introduction: High transport status is reported to be associated with increased mortality in peritoneal dialysis (PD). It has been hypothesized that this might be a result of a state of chronic inflammation and increased oxidative stress. We performed this pilot study to explore this hypothesis. Methods: Based on the standard peritoneal equilibration test, PD patients were divided in two transporter groups: LOW (Low + Low average) and HIGH (High + High Average). Markers of inflammation and oxidative stress were compared between the two groups, including C-reactive protein (CRP), plasma apoptogenic potential, monocyte HLA DR expression, Advanced Oxidative Protein Products (AOPP) and reactive carbonyl residues (RCO). Results: Of 42 patients (34 male/8 female) studied, 8 patients were LOW and 34 were HIGH transporters. Median values of CRP (1.39 vs. 0.62 mg/L), plasma apoptogenic potential (15 vs. 14.5%), AOPP (118.36 vs. 113.86 mu mol/L) and RCO (1.72 vs. 1.13 nmol/mg protein) were similar among LOW and HIGH transporters. However HIGH transporters had significantly lower monocyte HLA DR expression (mean fluorescent intensity (MFI) -197.89 vs. 124.98 units, p=0.02) compared with LOW transporters. Conclusions: Stable chronic PD patients with high peritoneal transport status have reduced monocyte HLA-DR expression, a biomarker of increased risk for infections. This could potentially contribute to a higher risk of mortality in this group.