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脂褐素在黄斑变性中的作用。在此过程中，我们开发了临床相关的方法来抑制脂褐素的形成（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。本应用的具体目的是：目的1)阐明脂褐素与视网膜健康的关系以及脂褐素形成的机制；a)确定减缓脂褐素的生物合成是否可以预防黄斑变性啮齿动物模型的眼老化和视力丧失；b)确定RPE中维生素A二聚体浓度的增加是否会导致脂褐素颗粒和赘肉的形成；c)确定快速增加脂褐素色素能否生成黄斑变性动物模型；2)阐明维生素A和维生素A二聚体在眼内的药代动力学：A)确定维生素A与d3 -维生素A在外节段交换所需的时间；b)建立维生素A二聚体的RPE半衰期；C)确定脂褐素色素的生物合成速率是否随着年龄的增长而增加，或者脂褐素色素本身是否随着年龄的增长而“积累”；d)比较维生素A与d3 -维生素A的视觉循环动力学。我们将通过使用我们实验室开发的新方法，减缓或加速动物体内脂褐素的形成，并将眼睛健康与脂褐素浓度联系起来，来实现这些特定的目标。为了评估脂褐素变化对眼睛健康的影响，我们采用标准方法，如组织组织学、眼底自身荧光、视网膜电图测量、炎症状态和维生素A二聚体的定量。为了阐明维生素A及其二聚体的眼药代动力学，我们使用氘或氚标记物种跟踪它们的命运和/或生物合成。我们打算证明维生素A二聚体（也称为脂褐素色素或A2E和atr二聚体）的生物合成是眼RPE细胞层中脂褐素颗粒（或沉积物）形成的早期和关键步骤；脂褐质颗粒会导致囊肿（或囊肿样物质）的形成，最终导致细胞死亡和视力受损。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，可以阻止脂褐素和drusen的形成，作为一种阻止最普遍形式的黄斑变性进展的方法。我们打算收集证据来表明，服用d3 -维生素A是一种安全、实用的方法，可以预防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.