Selective occlusion of choroidal neovascularization by photodynamic therapy with a water-soluble photosensitizer, ATX-S10.
OBJECTIVE
To determine the optimal treatment parameters for selective occlusion of choroidal neovascularization (CNV) by photodynamic therapy (PDT) by using the photosensitizer ATX-S10 and a diode laser (wavelength = 670 nm).


METHODS
Experimental CNV was induced in rat fundi by argon laser photocoagulation. The distribution of ATX-S10 in the chorioretina was analyzed by fluorescence microscopy, and the optimal treatment parameters for selective occlusion of CNV were investigated by changing the dosage and timing of laser irradiation. CNV closure and resulting damage of the surrounding tissue were documented by fluorescein angiography and light and electron microscopies.


RESULTS
Fluorescence of ATX-S10 was observed to be localized in the vascular lumen of the retina and choroid within 5 min after dye injection and increased in intensity in CNV up to 2-6 h and decreased rapidly in normal tissue. Laser irradiation with radiant exposures of 7.4 J/cm2 applied immediately after dye injection or with 22.0 J/cm2 at 2-4 h later effectively occluded the induced CNV without causing significant damage to normal retinal capillaries and large choroidal vessels.


CONCLUSIONS
PDT using ATX-S10 can selectively occlude CNV. ATX-S10 is a potentially useful photosensitizer for the treatment of CNV.
Obana
A
A
Department of Ophthalmology, Osaka City, University Medical School, Osaka, Japan.
Gohto
Y
Y
Kaneda
K
K
Nakajima
S
S
Takemura
T
T
Miki
T
T
D000818:Animals; D002829:Choroid / Q000648:ultrastructure; D020256:Choroidal Neovascularization / Q000175:diagnosis / Q000188:drug therapy* / Q000601:surgery; D004195:Disease Models, Animal; D005451:Fluorescein Angiography; D005654:Fundus Oculi; D007275:Injections, Intravenous; D017075:Laser Coagulation; D008856:Microscopy, Fluorescence; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D011166:Porphyrins / Q000008:administration & dosage / Q000627:therapeutic use*; D051381:Rats; D020318:Rats, Long-Evans; D012160:Retina / Q000648:ultrastructure; D016896:Treatment Outcome
C117772:ATX S10Na(II); D017319:Photosensitizing Agents; D011166:Porphyrins