Enhanced oxidant stress in synovial vessels of patients on hemodialysis

Objective To test the hypothesis that the susceptibility of synovial vessel s to redox uncoupling which could result in oxidative damage capable of pro moting beta(2)-microglobulin (beta(2)m) deposition. Methods The expression of oxidative markers by microvascular endothelial ce lls in hemodialysis (HD) patients, non-uremic patients and normal subjects was determined using immunostaining and Northern blotting. Results Synovial vascular endothelial cells of HD patients exhibited eviden ce of oxidant stress: induction of malondialdehyde (MDA) epitopes and heme oxygenase. These oxidative markers were not detectable in microvascular end othelial cells of other tissues from HD patients, as well as in the synovia l vessels of non-uremic or normal controls. Higher levels of heme oxygenase mRNA in synovia were seen in patients with beta(2)m deposition compared wi th patients without beta(2)m deposition. Conclusions Oxidative damage of the synovial microvasculature in uremic pat ients may be one of the factors which can promote deposition of beta(2)m in osteoarticular tissue.