Chronic renal failure (CRF) is often treated with peritoneal dialysis, although increased oxidative stress has been reported in such patients. The purpose of the current study was to analyze and compare oxidative stress and other compositional parameters in the saliva, serum and peritoneal dialytic fluid (PDF) of patients with chronic kidney disease (CKD), including predialysis CKD patients and end-stage renal disease (ESRD) patients treated with peritoneal dialysis. Twenty-three consenting patients participated in the current study. Saliva and serum samples collected from both groups and PDF from the dialysis patients were all examined for uric acid (UA), total antioxidant status, total protein and total albumin. The antioxidant enzyme peroxidase was examined both in saliva and serum, while the antioxidant enzyme superoxide dismutase (SOD) was examined solely in saliva. Various electrolytes were examined. Discrepancies were found between saliva and serum antioxidant status following peritoneal dialysis in ESRD patients. Oxidative stress was enhanced in the saliva but reduced in the serum. Significant changes in both oxidative-related and non-related parameters were demonstrated in saliva, serum and PDF. Salivary lactate dehydrogenase was substantially lower in the dialysis patients (by 92%, P = 0.02), as was the salivary UA concentration (by 22%, P = 0.05) and serum UA concentration (by 20%, P = 0.03). In contrast, salivary peroxidase and SOD were higher by 15% and 35%, respectively (P = 0.01), in these patients. We suggest monitoring salivary UA for assessing the baseline oral oxidative status of CRF and dialyzed patients.

Aim: To analyze various oxidative stress parameters in the saliva and serum of patients with chronic renal failure (CRF) and/or diabetes mellitus (DM), and to compare them in dialytic vs. pre-dialytic patients. Method: 50 consenting patients were divided into five subgroups of patients: severe CRF (dialytic) without DM, severe CRF (dialytic) with DM, mild CRF (pre-dialytic) without DM, mild CRF (pre-dialytic) with DM, and with DM but without CRF (controls). Uric acid (UA), peroxidase and total antioxidant status (TAS) were studied in both saliva and serum; superoxide dismutase (SOD) was evaluated only in saliva. Both saliva collection and serum harvesting were done simultaneously. Results: In severe-CRF patients without DM, median TAS, UA and SOD levels decreased following dialysis (54, 85, 48%, respectively), and peroxidase levels increased slightly (9%). In severe-CRF patients with DM, median TAS and SOD levels increased following dialysis (33 and 54%, respectively) while median UA and peroxidase levels decreased (68 and 10%, respectively). Conclusions: DM, CRF and hemodialysis were found to increase the oxidative stress burden in both serum and saliva. Therefore, antioxidant assessment may be used to monitor baseline oxidative status in these situations though larger randomized studies are in order.