QUANTITATIVE ANAYLSIS OF AGING RETINA

老年性黄斑病变(ARM)是发达国家老年人无法治愈的视力丧失的主要原因，改善治疗方法取决于对早期ARM的更好了解。根据我们的初步数据，我们假设早期老年性黄斑病变是动脉粥样硬化的一种眼部形式。根据这一假说，ARM的病理生理学涉及两个类似于大动脉内壁衰老和动脉粥样硬化的机制：大动脉内壁：与年龄相关的血清脂蛋白衍生的酯化胆固醇和非酯化胆固醇(EC和UC)与细胞外基质蛋白相关的沉积；以及与疾病相关的富含UC的物质的沉积，局部细胞的参与。利用人类供体眼的独特资源和建立的实验性动脉粥样硬化动物模型，我们提出了三个目标来检验这一假说的几个预测。1)在人眼中，我们将使用菲立磷脂荧光和数字显微镜来确定Bruch膜的EC和UC含量如何随年龄和视网膜位置的变化而变化。我们将通过确定溶剂如何影响菲立磷脂的荧光和超微结构来鉴定布鲁赫膜中富含EC的颗粒。我们将使用酶分析和气相色谱-质谱法对分离的Bruchs膜的脂质组成进行表征。2)在人眼中，我们将确定周边视网膜中出现的膜性碎片的形态。我们将使用纤维蛋白荧光、数字显微镜和超微结构体视学来确定膜碎片和光感受器外节的UC含量。3)在兔眼中，我们将使用放射自显影技术在组织切片中定位系统注射的酪胺-纤维二糖-低密度脂蛋白，以确定长期补充胆固醇是否会导致EC沉积在Bruchs膜EC中。这些目标的结果将在评估ARM和动脉粥样硬化在细胞外胆固醇积累和来源方面共享致病机制的程度上具有价值。这一信息是必需的，以确定是否应该考虑将有效的动脉粥样硬化治疗用于早期ARM的治疗。

Improved treatments for age-related maculopathy (ARM), the leading cause of untreatable vision loss among the elderly in the developed world, lie in better understanding of early ARM. On the basis of our preliminary data, we hypothesize that early age-related maculopathy is an ocular form of atherosclerosis. According to this hypothesis, the pathophysiology of ARM involves two mechanisms similar to those that occur during aging and atherosclerosis in the inner wall of the large arteries: According to this hypothesis, the inner wall of the large arteries: an age-related deposition of serum-lipoprotein-derived esterified cholesterol and unesterified cholesterol (EC and UC) in association with extracellular matrix proteins; and a disease-related deposition of a UC-rich material with the participation of local cells. Using a unique resource for human donor eyes and a well-established animal model for experimental atherosclerosis, we propose three aims to test several predictions of this hypothesis. 1) In human eyes, we will determine how the EC and UC content of Bruch's membrane varies with age and retinal location, using filipin fluorescence and digital microscopy. We will identify EC-rich particles in Bruch's membrane by determining how solvents affect filipin fluorescence and ultra-structure. We will characterize the lipid composition of isolated Bruch's membrane using an enzymatic assay and gas-chromatography-mass spectrometry. 2) In human eyes, we will determine the morphology of membranous debris occurs in peripheral retina. We will determine the UC content of membranous debris and photoreceptor outer segments using filipin fluorescence, digital microscopy, and ultrastructural stereology. 3) In rabbit eyes, we will determine if an extended diet of cholesterol supplementation results in deposition of EC in Bruch's membrane EC, using autoradiography to localized systemically injected radiolabeled tyramine-cellubiose-low density lipoprotein in tissue sections. Results from these aims will be valuable in assessing the extent to which ARM and atherosclerosis share pathogenetic mechanisms with regard to the accumulation and source of extracellular cholesterol. This information is required in order to determine if effective treatments for atherosclerosis should be considered for the treatment of early ARM.