Hypoxia-induced endogenous prostaglandin E2 negatively regulates hypoxia-enhanced aberrant overgrowth of rheumatoid synovial tissue.

Objective: During isometric exercise, the synovial joint tissue is prone to hypoxia, which is further enhanced in the presence of synovial inflammation. Hypoxia is also known to induce inflammatory cascades, suggesting that periodic hypoxia perpetuates synovitis in rheumatoid arthritis. We previously established an ex vivo cellular model of rheumatoid arthritis using the synovial tissue-derived inflammatory cells, which reproduced aberrant synovial overgrowth and pannus-like tissue development in vitro.