Is the beneficial effect of sulfasalazine due to inhibition of synovial neovascularization?

Angiogenesis is fundamental to support the continued synovial proliferation observed in rheumatoid arthritis. We investigated the effects of sulfasalazine and its metabolites on endothelial cell proliferation, a prerequisite to angiogenesis. At concentrations achieved in vivo sulfapyridine inhibited basal and endothelial cell growth factor stimulated endothelial cell proliferation. Sulfasalazine and 5 amino salicylic acid had no effect.