Apoptosis Detection in Human Choroidal Neovascular Membranes Treated With Photodynamic Therapy

Abstract

Abstract: : Purpose: Photodynamic therapy (PDT) has been found to be effective in patients with choroidal neovascularization (CNV) associated with age–related macular degeneration (AMD). We studied the presence of apoptosis in surgically excised CNV of patients with AMD who had PDT treatment or no prior PDT. Methods: Immunohistochemical analysis to detect the presence of apoptotic cells using TUNEL assays with Propidium Iodine counterstaining and M30 staining (specific for epithelial cells) was performed on surgically excised CNV from nine patients with AMD. Six patients had previous treatment with PDT and three patients did not have any previous laser treatment (PDT or thermal lasers) and served as controls. Results:TUNEL positive cells and M30 positive cells were identified in all surgically excised membranes. An increased number of apoptotic cells were found in the PDT treated lesions and were seen throughout the membrane; an increased number of positive cells around the edges of the membranes was observed and in some of the treated membranes there was an increased number of apoptotic cells around the vessels. Propidium iodine staining combine with the TUNEL assay was helpful in identifying true TUNEL–positive cells. RPE cells stained positive for apoptosis in both treated eyes and controls. Conclusions: TUNEL positive and M30 positive cells were found on surgically excised subretinal CNV associated with AMD. PDT treatment may increase apoptosis and play an important role in the mechanism of action of PDT.

Keywords: age-related macular degeneration • cell death/apoptosis • photodynamic therapy