Abstract
Abstract: :
Purpose:Photodynamic therapy (PDT) with intravenous verteporfin has been found to be effective in patients with choroidal neovascularization (CNV) associated with age–related macular degeneration (ARMD). We studied the expression of pigment epithelium–derived factor (PEDF), angiopoietin 1 (Ang–1), and vascular endothelial growth factor (VEGF) in surgically excised CNV of patients with ARMD who had and had not received prior PDT. Methods:Immunohistochemical analysis to detect the presence of PEDF, Ang–1, and VEGF was performed on surgically excised CNV from ten patients with AMD. Six patients had previous treatment with PDT and four patients did not have any previous laser treatment and were used as controls. Results:PEDF, Ang–1, and VEGF were expressed in all surgically excised membranes, regardless of the presence or absence of prior PDT treatment. VEGF and angiopoietin–1 immunostaining was positive around the RPE layer, RPE cells and perivascular cells. PEDF was positive within the RPE cells and RPE layer, and there was a slight increase in PEDF expression in the PDT treated membranes. VEGF expression was higher in membranes with active neovascularization. Regional variations in expression of all factors studied were also present due to growth of new vessels in the peripheral regions of the membranes. Conclusions:Surgically excised subretinal CNV associated with ARMD express PEDF, Ang–1 and VEGF, regardless of prior PDT treatment. We did not find any significant differences between the expression of these factors within PDT–treated human CNV and control membranes. This may be due to a negligible effect of PDT on RPE cells, the long duration (3 months) between PDT treatment and surgical excision of the CNV or a selection bias since all of the PDT treated membranes failed to respond to initial laser treatment.
Keywords: age–related macular degeneration • photodynamic therapy • immunohistochemistry