NSAIDs inhibit neovascularization of choroid through HO-1-dependent pathway.

Intraocular neovascularization is the leading cause of severe visual loss and anti-vascular endothelial growth factor (VEGF) therapy is currently performed for choroidal neovascularization (CNV). Despite its potent anti-angiogenic effect, there are concerns about its long-term safety. Non-steroidal anti-inflammatory drugs (NSAIDs) are common therapeutic agents used for treating inflammatory diseases, and their anti-stress effects are attracting attention now. We studied the effects of topical NSAIDs on CNV, focusing on anti-stress proteins. Cultured retinal pigment epithelium (RPE) cells were treated with NSAIDs: bromfenac, indomethacin, or vehicle control. Transcription factor NF-E2-related factor 2 (Nrf2) and its downstream anti-oxidant protein heme oxygenase (HO)-1 were assessed using western blot and immunohistochemistry. As a result, NSAIDs induced translocation of Nrf2 into the nucleus and the robust expression of HO-1 in a dose- and time-dependent manner. Flow cytometric analysis revealed that bromfenac inhibited H(2)O(2)-induced apoptosis in cultured RPE cells. Next, we studied the effects of topical bromfenac on laser-induced CNV model in rat. The expressions of Nrf2 and HO-1, infiltrations of ED-1-positive macrophages at CNV lesions and size were analyzed. VEGF in the ocular fluid of these rats was also measured using enzyme-linked immunosorbent assay. Rats administered an inhibitor of HO-1 stannic mesoporphyrin (SnMP) were also studied. The results showed that topical bromfenac led to translocation of Nrf2 and induction of HO-1 in CNV lesions and that the number of infiltrating macrophages at the CNV lesion decreased. The sizes of CNV lesions were significantly smaller in bromfenac-treated rats than control CNV, and the effects were diminished by SnMP. VEGF increased in the ocular fluid after laser treatment and was inhibited by bromfenac and SnMP canceling these effects. NSAIDs inhibit CNV through the novel anti-stress protein HO-1-dependent pathway, indicating its potential therapeutic value for various intraocular angiogenic diseases including CNV.