Comparison of multiple reduced-dose and standard light application in photodynamic therapy in an animal model of choroidal neovascularization.
نویسندگان
چکیده
BACKGROUND Current photodynamic therapy (PDT) for choroidal neovascularization (CNV) uses a standard radiant exposure of 50 J/cm2 at an irradiance of 600 mW/cm2. However, low-intensity PDT with verteporfin for neovascular tissue has been shown to be more effective than regular high-intensity PDT in an animal model of healthy choroids and corneal neovascularization. Low-intensity PDT also supposedly induces less retinal damage. In this study, we compared the effect of reduced-dose and standard light application PDT in an animal model of CNV. METHODS A laser injury model was used to induce CNV 3 weeks prior to PDT in brown Norway rats. The CNV lesions were then treated with verteporfin PDT with a dose of verteporfin 6.0 mg/m2 and 5 activating doses of light energy (43, 53, 63, 73 and 83 seconds). Closure of CNV was assessed by fundus fluorescein angiography (FAG). Histopathologic study was done after the last FAG. RESULTS PDT with verteporfin significantly reduced the CNV area compared with control non-treated groups 1 week after PDT (p < 0.05). Only those lesions treated for 63 seconds or longer retained their significantly attenuating effect on CNV up to 3 weeks after PDT. There was no significant difference between the inhibition effects induced by reduced-intensity light application for 63 or 73 seconds compared to the standard radiant exposure (83 seconds). Histopathologic study showed that eyes treated with PDT showed significantly less extent and vascularity of CNV lesion than control lesions. CONCLUSION Reduced-intensity PDT with 63-second duration seemed to be as effective as standard dose for CNV suppression. Considering the possible retinal damage following standard PDT, the PDT dose might be adjusted to reduce side effects. Further preclinical study will provide more data on what constitutes appropriate dosimetry for effective and safe PDT in CNV.
منابع مشابه
Factor VII-verteporfin for targeted photodynamic therapy in a rat model of choroidal neovascularization.
PURPOSE To study the efficacy and safety of factor VII (fVII)-verteporfin for targeted photodynamic therapy (TPT) compared with nontargeted photodynamic therapy (PDT) in a rat model of choroidal neovascularization (CNV). fVII-verteporfin binds tightly and specifically to tissue factor, which is expressed on endothelial cells of CNV but not normal vasculature. METHODS Multiple CNV lesions were...
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Verteporfin photodynamic therapy in the rat model of choroidal neovascularization: angiographic and histologic characterization.
PURPOSE To develop a model of verteporfin photodynamic therapy (PDT) for experimental choroidal neovascularization CNV in the rat. METHODS A laser injury model was used to induce experimental CNV in rats. The transit and accumulation of the photosensitizer verteporfin was assessed angiographically in CNV lesions, to determine the optimal time for delivery of light energy. The CNV lesions were...
متن کاملSelective photodynamic therapy by targeted verteporfin delivery to experimental choroidal neovascularization mediated by a homing peptide to vascular endothelial growth factor receptor-2.
OBJECTIVE To evaluate the feasibility, efficacy, and selectivity of photodynamic therapy (PDT) using targeted delivery of verteporfin to choroidal neovascularization (CNV) in the rat laser-injury model of CNV. METHODS We performed PDT in rat eyes on experimental CNV and normal retina and choroid using verteporfin conjugates. A targeted verteporfin conjugate was made by conjugating verteporfin...
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Objective(s) Although photodynamic therapy is considered as a noninvasive method, most photosensitizers are susceptible to ultrasound. Therefore, it is expected that the combination of two activation methods might have a synergistic effect. This probable effect has been investigated in this study. Materials and Methods This study was conducted on colon carcinoma ...
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ورودعنوان ژورنال:
- Journal of the Chinese Medical Association : JCMA
دوره 71 3 شماره
صفحات -
تاریخ انتشار 2008