Hammer Martin, Königsdörffer Ekkehart, Liebermann Christiane, Framme Carsten, Schuch Günter, Schweitzer Dietrich, Strobel Jürgen
Department of Ophthalmoloy, University of Jena, Bachstr. 18, 07740, Jena, Germany.
Graefes Arch Clin Exp Ophthalmol. 2008 Jan;246(1):105-14. doi: 10.1007/s00417-007-0639-9. Epub 2007 Jul 26.
Post-translational protein modification by lipid peroxidation products or glycation is a feature of aging as well as pathologic processes in postmitotic cells at the ocular fundus exposed to an oxidative environment. The accumulation of modified proteins such as those found in lipofuscin and advanced glycation end products (AGEs) contribute greatly to the fundus auto-fluorescence. The distinct fluorescence spectra of lipofuscin and AGE enable their differentiation in multispectral fundus fluorescence imaging.
A dual-centre consecutive case series of 78 pseudo-phacic patients is reported. Digital colour fundus photographs as well as auto-fluorescence images were taken from 33 patients with age related macular degeneration (AMD), 13 patients with diabetic retinopathy (RD), or from 32 cases without pathologic findings (controls). Fluorescence was excited at 475-515 nm or 476-604 nm and recorded in the emission bands 530-675 nm or 675-715 nm, respectively. Fluorescence images excited at 475-515 nm were taken by a colour CCD-camera (colour-fluorescence imaging) enabling the separate recording of green and red fluorescence. The ratio of green versus red fluorescence was calculated within a representative region of each image.
The 530-675 nm auto-fluorescence in AMD patients was dominated by the red emission (green vs. red ratio, g/r = 0.861). In comparison, the fluorescence of the diabetics was green-shifted (g/r = 0.946; controls: g/r = 0.869). Atrophic areas (geographic atrophy, laser scars) showed massive hypo-fluorescence in both emission bands. Hyper-fluorescent drusen and exudates, unobtrusive in the colour fundus images as well as in the fluorescence images with emission >667 nm, showed an impressive green-shift in the colour-fluorescence image.
Lipofuscin is the dominant fluorophore at long wavelengths (>675 nm or red channel of the colour fluorescence image). In the green spectral region, we found an additional emission of collagen and elastin (optic disc, sclera) as well as deposits in drusen and exudates. The green shift of the auto-fluorescence in RD may be a hint of increased AGE concentrations.
脂质过氧化产物或糖基化作用引起的蛋白质翻译后修饰是衰老的一个特征，也是暴露于氧化环境的眼后极部有丝分裂后细胞病理过程的一个特征。修饰蛋白的积累，如脂褐素和晚期糖基化终产物（AGEs）中的蛋白，对眼底自发荧光有很大影响。脂褐素和AGEs独特的荧光光谱使得它们在多光谱眼底荧光成像中得以区分。
报告了一个双中心连续病例系列，共78例拟晶状体患者。对33例年龄相关性黄斑变性（AMD）患者、13例糖尿病视网膜病变（RD）患者或32例无病理发现的患者（对照组）拍摄了数字彩色眼底照片和自发荧光图像。荧光分别在475 - 515 nm或476 - 604 nm激发，并分别在530 - 675 nm或675 - 715 nm发射波段记录。在475 - 515 nm激发的荧光图像由彩色CCD相机拍摄（彩色荧光成像），能够分别记录绿色和红色荧光。在每个图像的代表性区域内计算绿色与红色荧光的比率。
AMD患者530 - 675 nm的自发荧光以红色发射为主（绿色与红色比率，g/r = 0.861）。相比之下，糖尿病患者的荧光向绿色偏移（g/r = 0.946；对照组：g/r = 0.869）。萎缩区域（地图样萎缩、激光瘢痕）在两个发射波段均显示大量低荧光。高荧光的玻璃膜疣和渗出物在彩色眼底图像以及发射>667 nm的荧光图像中不明显，但在彩色荧光图像中显示出明显的绿色偏移。
脂褐素是长波长（>675 nm或彩色荧光图像的红色通道）的主要荧光团。在绿色光谱区域，我们发现胶原蛋白和弹性蛋白（视盘、巩膜）以及玻璃膜疣和渗出物中的沉积物有额外发射。RD患者自发荧光的绿色偏移可能提示AGE浓度增加。
