Oxidative stress markers in young hemodialysis patients - a pilot study

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.

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.

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.

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.