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.