The role and mechanisms of lipofuscin formation in macular degeneration

描述（由申请人提供）：本研究的总体目标是更好地了解眼部脂褐素在黄斑变性中的作用。在这样做的过程中，我们开发了临床相关的方法来抑制脂褐素形成（作为黄斑变性的可能干预措施），并开发了脂褐素诱导的黄斑变性的动物模型。本申请的具体目的是：目的1）阐明脂褐素与视网膜健康之间的关系以及脂褐素形成的机制：a）确定在黄斑变性的啮齿动物模型中减缓脂褐素生物合成是否可以防止眼老化和视力丧失; B）确定增加RPE中维生素A二聚体的浓度是否导致脂褐素颗粒和玻璃疣的形成;和c）确定是否可以通过快速增加脂褐素色素产生黄斑变性的动物模型;和AIM 2）阐明维生素A和维生素A二聚体在眼睛中的药代动力学：a）确定在外节中将维生素A交换为D3-维生素A所需的时间; B）建立维生素A二聚体的RPE半衰期; c）确定脂褐质色素生物合成的速率是否随年龄增加或脂褐质色素本身是否随年龄“积累”，和d）比较维生素A与D3-维生素A的视觉周期动力学。我们将通过减缓或加速动物中脂褐素的形成来实现这些特定目标，使用我们实验室开发的新方法，并将眼睛健康与脂褐素浓度相关联。在评估眼健康的变化，在脂褐质，我们采用标准的方法，如组织组织学，眼底自发荧光，视网膜电图测量，炎症状态和定量的维生素A二聚体。为了阐明维生素A及其二聚体的眼部药代动力学，我们使用氘或氚标记的物质追踪它们的命运和/或生物合成。我们打算表明维生素A二聚体（也称为脂褐素色素或A2 E和ATR-二聚体）的生物合成是在眼睛的RPE细胞层中形成脂褐素颗粒（或沉积物）的早期和关键步骤;脂褐素颗粒导致玻璃疣（或玻璃疣样物质）的形成并最终导致细胞死亡和视力损害。我们打算表明，停止维生素A二聚体的生物合成是一种有效的临床策略，以阻止脂褐素和玻璃疣的形成，作为一种方法，以阻止黄斑变性的最普遍的形式的进展。我们打算收集证据，以证明D3-维生素A的管理是一个安全，实用的方法，以防止几种形式的黄斑变性的进展。

DESCRIPTION (provided by applicant): The overall goal of this research is to better understand the role of ocular lipofuscin in macular degeneration. In doing so we develop clinically relevant ways to inhibit lipofuscin formation (as possible interventions for macular degeneration) and develop animal models of lipofuscin-induced macular degeneration. The specific aims of this application are: AIM 1) elucidate the relationship between lipofuscin and retinal health and the mechanism of lipofuscin formation: a) determine whether slowing lipofuscin biosynthesis can prevent ocular aging and vision loss in rodent models of macular degeneration; b) determine whether increasing the concentration of vitamin A dimers in the RPE leads to the formation of lipofuscin granules and drusen; and c) determine whether animals models of macular degeneration can be generated by rapidly increasing lipofuscin pigments; and AIM 2) elucidate pharmacokinetics vitamin A and vitamin A dimers in the eye: a) determine the time it takes to swap vitamin A for D3-vitamin A in the outer segments; b) establish the RPE half life of vitamin A dimers; c) determine whether the rate of lipofuscin pigment biosynthesis increases with age or whether lipofuscin pigments themselves "accumulate" with age, and; d) compare visual cycle kinetics of vitamin A vs. D3-vitamin A. We will achieve these specific aims by slowing down or speeding up lipofuscin formation in animals, using novel methods developed in our lab, and correlating eye health to lipofuscin concentration. In evaluating eye health in response to changes in lipofuscin we employ standard methods such as, tissue histology, fundus autofluorescence, electroretinogram measurements, inflammatory status and quantification of vitamin A dimers. For the elucidation of the ocular pharmacokinetics of vitamin A and its dimers we track their fate and/or biosynthesis using deuterium or tritium labeled species. We intend to show that the biosynthesis of vitamin A dimers (also called or lipofuscin pigments or A2E and ATR-dimer) is an early and critical step in the formation of lipofuscin granules (or deposits) in the RPE cell layer of the eye; that lipofuscin granules lead to the formation of drusen (or drusen like material) and ultimately cell death and vision impairment. We intend to show that stopping the biosynthesis of vitamin A dimers is an effective clinical strategy to stopping the formation of lipofuscin and drusen, as a method to stop the progression of the most prevalent forms of macular degeneration. We intend to gather evidence to show that the administration of D3-vitamin A is a safe, practical, method to prevent the progression of several forms of macular degeneration.