Effect of verteporfin photodynamic therapy on endostatin and angiogenesis in human choroidal neovascular membranes

Aim: To evaluate the effect of verteporfin photodynamic therapy (PDT) on endostatin with regard to expression of vascular endothelial growth factor (VEGF) in human choroidal neovascular membranes (CNVs) secondary to age-related macular degeneration. Methods: A retrospective review of an interventional case series of 68 patients who underwent removal of CNV. 29 patients were treated with PDT 3-655 days before surgery. 39 CNVs without previous treatment were used as controls. CNVs were stained for CD34, CD105, Ki-67, cytokeratin 18, endostatin, E-selectin and VEGF. "Predominance score of VEGF over endostatin" (mean) was defined as the difference between VEGF and endostatin staining scores. Results: In four CNVs treated by PDT 3 days previously, PS was significantly higher in the retinal pigment epithelium (mean = 2.5, p = 0.006) and stroma (mean = 2, p = 0.015) than in the control group (mean = 0). At longer post-PDT intervals, PS was significantly decreased in the retinal pigment epithelium (mean = 0, p = 0.019) and stroma (mean = 0, p = 0.015). Proliferative activity was high (p = 0.023), but mostly related to inflammatory cells. PDT did not influence E-selectin expression significantly. Conclusions: VEGF predominance over endostatin early after PDT might contribute to enhanced angiogenic activity associated with recurrences. Strategies upregulating or replacing endostatin early after PDT might increase the effectiveness of PDT.