Selective photodynamic effects of the new photosensitizer ATX-S10(Na) on choroidal neovascularization in monkeys.
OBJECTIVE
To determine the optimal treatment variables for photodynamic therapy (PDT) with new photosensitizer ATX-S10(Na) (13,17-bis[1-carboxypropionyl] carbamoylethyl-8-etheny-2-hydroxy-3-hydroxyiminoethyliden e-2,7,12,18-tetranethyl 6 porphyrin sodium) to induce selective occlusion of choroidal neovascularization (CNV) in nonhuman primate eyes.


METHODS
Experimental CNV was induced in monkey eyes by laser photocoagulation, and PDT was performed in neovascularized and healthy eyes with different treatment variables. At 0 to 150 minutes after 4-, 8-, and 12-mg/kg of body weight intravenous injections of ATX-S10(Na), a diode laser was irradiated at the dose of 1 to 127 J/cm2 (wavelength, 670 nm). Vascular occlusion induced by PDT was evaluated using fluorescein angiography, indocyanine green angiography, and histological examination at 1 day to 4 weeks after irradiation.


RESULTS
Selective occlusion of CNV without damage to healthy retinal and choroidal capillaries was achieved in the following conditions: 30 to 74 J/cm2 irradiation at 30 to 74 minutes after the 8-mg/kg injection, and 1 to 29 J/cm2 irradiation at 30 to 74 minutes or 30 to 74 J/cm2 irradiation at 75 to 150 minutes after the 12-mg/kg dye injection. Regrowth of CNV often occurred when the retina was heavily injured by excessive PDT.


CONCLUSIONS
By using optimal treatment variables, PDT using ATX-S10(Na) induces selective occlusion of CNV in nonhuman primate eyes, providing the possibility of therapeutic application to the clinical practice.


CONCLUSIONS
Occlusion of CNV without direct damage to the sensory retina is useful to preserve visual acuity in patients with exudative age-related macular degeneration. A clinical trial of PDT using ATX-S10(Na) is desirable.
Obana
A
A
Department of Ophthalmology, Osaka City University Medical School, Japan. akira-kun@med.osaka-cu.ac.jp
Gohto
Y
Y
Kanai
M
M
Nakajima
S
S
Kaneda
K
K
Miki
T
T
D000818:Animals; D002829:Choroid / Q000098:blood supply / Q000601:surgery; D020256:Choroidal Neovascularization / Q000188:drug therapy* / Q000209:etiology / Q000473:pathology; D004195:Disease Models, Animal; D005451:Fluorescein Angiography; D007208:Indocyanine Green; D017075:Laser Coagulation; D008252:Macaca fascicularis; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D011166:Porphyrins / Q000627:therapeutic use*
C117772:ATX S10Na(II); D017319:Photosensitizing Agents; D011166:Porphyrins; D007208:Indocyanine Green