Triamcinolone acetonide suppresses early proangiogenic response in retinal pigment epithelial cells after photodynamic therapy in vitro

Objective: To investigate the expression of proangiogenic and antiangiogenic factors, vascular endothelial growth factor ( VEGF) and pigment epithelium-derived factor ( PEDF) in retinal pigment epithelial ( RPE) cells after photodynamic therapy ( PDT), especially focusing on their change in the presence of triamcinolone acetonide. Methods: Firstly, the cellular uptake of verteporfin was quantified after confluent ARPE-19 ( human retinal pigment epithelial) cells were exposed to 5 mu g/ml verteporfin combined with or without 1 mu g/ml triamcinolone acetonide for 1 h. Secondly, ARPE-19 cells exposed to various doses of verteporfin were irradiated with 120 mJ/cm(2) light. After incubation with or without 1 mu g/ml triamcinolone acetonide for 2 days, cell viability and expressions of VEGF and PEDF were assessed. Results: Cellular uptake of verteporfin was not significantly changed by the presence of 1 mu g/ml triamcinolone acetonide. In addition, 0.01 - 0.1 mg/ml of verteporfin showed a dose-dependent toxicity on the ARPE-19 cells 2 days after the light exposure. The presence of verteporfin at a concentration of 0.01 mg/ml did not affect the cell viability but significantly increased VEGF ( p < 0.001) and reduced PEDF ( p = 0.03) expression. Administration of triamcinolone acetonide significantly suppressed both this increase in VEGF ( p < 0.001) and decrease in PEDF ( p = 0.001). Conclusions: VEGF was increased and PEDF reduced in cultured RPE cells shortly after PDT even at a sublethal dose. Triamcinolone acetonide suppressed this proangiogenic response.