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

Abstract

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. Firstly, the cellular uptake of verteporfin was quantified after confluent ARPE-19 (human retinal pigment epithelial) cells were exposed to 5 microg/ml verteporfin combined with or without 1 microg/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 microg/ml triamcinolone acetonide for 2 days, cell viability and expressions of VEGF and PEDF were assessed. Cellular uptake of verteporfin was not significantly changed by the presence of 1 microg/ml triamcinolone acetonide. In addition, 0.01-0.1 microg/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 microg/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). VEGF was increased and PEDF reduced in cultured RPE cells shortly after PDT even at a sublethal dose. Triamcinolone acetonide suppressed this proangiogenic response.