Schmidt-Erfurth U, Hasan T, Gragoudas E, Birngruber R
Medizinisches Laserzentrum und Augenklinik, Medizinischen Universität zu Lübeck.
Ophthalmologe. 1994 Dec;91(6):789-95.
Conventional photocoagulation of subretinal membranes induces a non-selective thermal necrosis of retinal and choroidal layers with extensive collateral damage. Hence, this modality is of limited value for the treatment of lesions close to or underneath the fovea. Photodynamic therapy uses systemic administration of a primarily non-toxic photosensitizer with localized light activation of the dye by subthermal light intensities. It provides intraluminal vascular occlusion by means of localized endothelial damage. Enhanced selectivity for neovascularization is achieved by the use of carrier molecules with increased receptor density on proliferating endothelial cells, e.g. low-density lipoproteins (LDL). Benzoporphyrin derivative (BPD), currently in phase I clinical trials, was complexed with LDL. BPD-LDL was used for photodynamic occlusion of the choriocapillary layer in the rabbit model. Subretinal photothrombosis and collateral damage to neural retina, retinal pigment epithelium, Bruch's membrane and large choroidal vessels were documented by ophthalmoscopy, angiography and light and electron microscopic histology. Homogenous vascular occlusion without retinal destruction was induced with light doses as low as 10 J/cm2. Selective neovascular occlusion by photodynamic therapy may allow occlusion of subretinal membranes while preserving retinal integrity and visual function.
视网膜下膜的传统光凝会导致视网膜和脉络膜层的非选择性热坏死，并伴有广泛的间接损伤。因此，这种方法对于治疗靠近黄斑中心凹或其下方的病变价值有限。光动力疗法通过全身给药一种基本无毒的光敏剂，并利用亚热光强度对染料进行局部光激活。它通过局部内皮损伤实现管腔内血管闭塞。通过使用在增殖内皮细胞上具有增加受体密度的载体分子，例如低密度脂蛋白（LDL），可提高对新生血管形成的选择性。目前处于I期临床试验的苯并卟啉衍生物（BPD）与LDL复合。BPD-LDL用于兔模型中脉络膜毛细血管层的光动力闭塞。通过检眼镜检查、血管造影以及光镜和电镜组织学记录了视网膜下光血栓形成以及对神经视网膜、视网膜色素上皮、布鲁赫膜和大脉络膜血管的间接损伤。低至10 J/cm2的光剂量即可诱导均匀的血管闭塞而不破坏视网膜。光动力疗法选择性新生血管闭塞可能允许在保留视网膜完整性和视觉功能的同时闭塞视网膜下膜。
