Photodynamic effect using amphiphilic photosensitizer ATX–S10(Na) on experimental choroidal neovascularization in monkeys.

Abstract

Abstract: : Purpose: To evaluate the photodynamic effect of our new amphiphilic photosensitizer, ATX–S10 (Na), on experimental choroidal neovascularization (CNV) in monkey eyes. We examined the parameters of settings in which ATX–S10(Na) can be safety utilized clinically, particularly the dose range at which effects on chorio–retinal tissue are minimal. Methods: Experimental CNVs were induced by intense photocoagulation with a krypton laser in the monkey retina. Ten to fourteen days after intense photocoagulation, fluorescein angiography (FA) was performed to confirm the presence of CNVs. CNV lesions were irradiated with a diode laser (wavelength = 670 nm) (Hamamatsu Photonics) at a dose of 30–60 J/cm², 5 to 36 minutes, with a 600mW/ cm² spot size after intravenous injection of 2.5mg/Kg body weight of ATX–S10 (Na). Vascular occlusions were evaluated by FA and histopathological analysis, one to seven days after irradiation. Results: Within 23–36 minutes after ATX–S10 (Na) injection and irradiation with 50–60 J/cm², FA showed no fluorescein dye leakage from CNVs. These findings were obtained one day to seven days after photodynamic therapy(PDT). Retinal and choroidal vessels showed perfusion on FA. No apparent changes were seen in the inner layer of the retina on histological analysis. Conclusions:PDT using a clinically administrable dose of ATX–S10(Na) induces selective occlusion of CNVs in non–human primate eyes without damaging the retina.

Keywords: photodynamic therapy • choroid: neovascularization • pathology: experimental