Objective: To test the hypothesis that the susceptibility of synovial vessels to redox uncoupling which could result in oxidative damage capable of promoting beta 2-microglobulin (beta 2 m) deposition.
Methods: The expression of oxidative markers by microvascular endothelial cells 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 evidence of oxidant stress: induction of malondialdehyde (MDA) epitopes and heme oxygenase. These oxidative markers were not detectable in microvascular endothelial cells of other tissues from HD patients, as well as in the synovial 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 with patients without beta 2 m deposition.
Conclusions: Oxidative damage of the synovial microvasculature in uremic patients may be one of the factors which can promote deposition of beta 2 m in osteoarticular tissue.