Oxidative stress markers in young hemodialysis patients - a pilot study.

ABSTRACT

AIMS: Studies in young hemodialysis patients without significant comorbidities might increase the understanding of incipient vascular pathology in uremia. We investigated whether a specific pattern of oxidative stress markers with potential prognostic significance could be identified in this population. MATERIAL AND METHODS: We performed a cross-sectional matched case control study of 25 young hemodialysis patients (age 18 - 40 years) without known comorbidity factors. Patients were matched pairwise to healthy controls, and markers of oxidative stress were analyzed for associations with surrogate parameters of vascular structure and function. RESULTS: Oxidized low-density lipoproteins (OxLDL) were similar in patients and controls whereas conjugated dienes were increased in the very low-density lipoproteins (VLDL) fraction (20 +/- 6 vs. 12 +/- 5 micromol/l, p < 0.0001), but not in the low-density lipoproteins (LDL) fraction (16 +/- 6 vs. 18 +/- 6 micromol/l). Superoxide dismutase (SOD) activity was diminished in patients (1,117 +/- 151 vs. 1,299 +/- 88 U/g Hb, p < 0.0001), but there was no difference in glutathione peroxidase (GPx) activity. Oxidative stress expressed as the ratio of oxidized and reduced glutathione (GSSG/GSH) was increased in patients (0.25 +/- 0.18 vs. 0.13 +/- 0.04, p = 0.0048). Intima-media thickness (IMT) of the common carotid artery (0.70 +/- 0.12 vs. 0.62 +/- 0.08 mm, p = 0.0007) was significantly increased, and postischemic peak flow (PIPF) by venous occlusion plethysmography was severely diminished in patients (632 +/- 319 vs. 1,057 +/- 543% of basal flow, p < 0.0001). None of the markers of oxidative stress was independently associated with IMT or PIPF or a significant discriminator between patients and controls by multivariate regression. CONCLUSIONS: In this pilot study of exclusively young patients on hemodialysis, oxidative stress markers were of limited clinical value in identifying young patients at risk for vascular complications.