Kliffen M, de Jong P T, Luider T M
Institute of Ophthalmology, Erasmus University, Rotterdam-Dijkzigt, The Netherlands.
Lab Invest. 1995 Aug;73(2):267-72.
Age-related maculopathy (ARM) is the most common cause of blindness in the elderly in the western world. Its early stage is characterized by many histopathologic changes, including two extracellular deposits, basal laminar deposit (BLD) and drusen. The origin and chemical composition of BLD and drusen are unknown and are considered to be important in the development of ARM, so we analyzed proteins in human macular tissue associated with ARM.
Homogenized macular extracts of 15 human eyes with ARM and 10 age-matched control eyes were examined by two-dimensional electrophoresis. The proteins in the gels were silver-stained, and the obtained protein patterns were analyzed by a computer-imaging system.
Five glycoproteins were specifically present in human maculae with ARM (p = 0.0009). One of the spots was characterized by sequence analysis as haptoglobin beta-chain, and another had a high homology with a part of the interphotoreceptor retinoid-binding protein precursor. However, the 100% matching of the latter was not statistically significant because we could only sequence eight amino acids of this protein.
The known association between haptoglobin beta-chain and atherosclerosis and the increase of this glycoprotein in human maculae with ARM supports the recently described relationship between atherosclerosis and ARM found in an epidemiologic study. Furthermore, the neovascular growth-stimulating properties of haptoglobin warrant further research into haptoglobin as a possible inducing agent of late stages of ARM.
年龄相关性黄斑病变（ARM）是西方世界老年人失明的最常见原因。其早期阶段具有许多组织病理学变化，包括两种细胞外沉积物，即基底膜沉积物（BLD）和玻璃膜疣。BLD和玻璃膜疣的起源和化学成分尚不清楚，并且被认为在ARM的发展中很重要，因此我们分析了与ARM相关的人黄斑组织中的蛋白质。
通过二维电泳检查了15只患有ARM的人眼和10只年龄匹配的对照眼的匀浆黄斑提取物。对凝胶中的蛋白质进行银染，并通过计算机成像系统分析获得的蛋白质图谱。
五种糖蛋白在患有ARM的人黄斑中特异性存在（p = 0.0009）。其中一个斑点经序列分析鉴定为触珠蛋白β链，另一个与光感受器间类视黄醇结合蛋白前体的一部分具有高度同源性。然而，后者的100%匹配在统计学上并不显著，因为我们只能对该蛋白质的八个氨基酸进行测序。
触珠蛋白β链与动脉粥样硬化之间的已知关联以及该糖蛋白在患有ARM的人黄斑中的增加支持了一项流行病学研究中最近描述的动脉粥样硬化与ARM之间的关系。此外，触珠蛋白的促新生血管生长特性值得进一步研究将触珠蛋白作为ARM晚期可能的诱导剂。
