Birth and Death of Choriocapillaris.

脉络膜毛细血管的出生和死亡。

• 批准号: 8290655
• 负责人: Gerard Anthony Lutty
• 金额: $ 48.84万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-01 至 2017-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8290655
• 关键词: Affect; Age; Albumins; Architecture; Birth; Blood Vessels; Blood capillaries; Bruch' s basal membrane structure; Cause of Death; Caveolae; Cell Death; Cessation of life; Charge; Choroid; Chronology; Collection; Defect; Deposition; Development; Drusen; Endothelial Cells; Epithelial; Excision; Exudative age-related macular degeneration; Eye; Functional disorder; Gold; Grant; Human; In Vitro; Knock-out; Knowledge; Label; Lipids; Lipoproteins; Lobular; Manuscripts; Membrane; Mus; Nonexudative age-related macular degeneration; Nutrient; Oxygen; Photoreceptors; Positioning Attribute; Property; Proteins; Publishing; Respiratory Diaphragm; Retina; Retinal; Retinal Degeneration; Serum; Serum Proteins; Side; Specimen; Structure of retinal pigment epithelium; System; Therapeutic; Third Pregnancy Trimester; Tight Junctions; Time; Toxic effect; Transmission Electron Microscopy; Transport Process; Up-Regulation; Vascular Endothelial Growth Factors; aged; alpha 2-Glucoproteins; capillary; caveolin 1; coated pit; cohort; crosslink; cytotoxic; glycation; in vivo; macromolecule; monolayer; nanoparticle; neovascular; prevent; vasculogenesis; wasting

DESCRIPTION (provided by applicant): The choriocapillaris (CC) is a lobular, fenestrated vasculature that provides all of the oxygen and serum nutrients to the RPE and photoreceptors. We have elaborated the birth of human CC by hemo-vasculogenesis and the death of CC in wet and dry AMD in the last grant period. In dry AMD, CC cell death is related to loss of adjacent RPE. In wet AMD, loss of CC occurs in advance of choroidal neovascular membrane (CNV) formation, which is unexplained to date. We have observed high concentrations of serum proteins around CC in dry and wet AMD. The reason for this accumulation and influence of these proteins on CC is unknown. Although it is assumed that CC provides the nutrients for RPE and photoreceptors and removes waste, the exact mechanisms of transport are unknown. The proposed studies will characterize CC's normal transport mechanisms via fenestrations, caveolae, and coated pits. These mechanisms will be evaluated using gold nanoparticles of defined sizes, tagged serum proteins, and tagged serum lipids. We will determine if dysregulation in CC transport affects protein accumulation by using mice lacking caveolae (knock out cav-1, the major component in the caveolae system), or fenestrations (RPE-produced VEGF knocked out or neutralized), or mice with RPE over expressing VEGF, or producing basal laminar deposits. The proposed studies will determine the effects of Bruchs membrane deposits on CC transport and the effects of CC transport defects on deposit formation. We hypothesize that dysfunction in CC transport results in the serum protein accumulation in choroid we observe, which is toxic to CC and may be the reason that CC die in AMD. We will evaluate the toxicity of serum proteins (albumin, CRP, and alpha-2 macroglobulin with and without glycation) on choroidal endothelial cells (CEC) in vitro and determine if those serum proteins cause loss of tight junctions, changes in numbers of caveolae or fenestrations in CEC. It is also assumed that CC dysfunction is involved in AMD. Our preliminary studies demonstrated that loss in fenestrations is associated with Bruchs membrane deposits and RPE loss. In a large collection of AMD eyes that Greg Hageman has prepared for TEM, we will determine if CC fenestrations, caveolae, coated pits and/or tight junctions change in human AMD and the association of basal deposits, drusen, and RPE loss with these changes. In conclusion, this proposal will define the normal transport processes used by CC to supply nutrients to retina. We will also determine if these transport processes are altered in AMD. We will determine if serum proteins that accumulate with age in choroid contribute to dysfunction in CC transport and the death of CC we have observed in AMD. We will investigate how reduced or elevated VEGF changes CC transport. This new knowledge of CC transport and how it changes in AMD will be invaluable in developing new systemic therapeutic nanoparticles for preventing retinal degeneration and CNV that occurs in AMD. PUBLIC HEALTH RELEVANCE: This study will determine how the choriocapillaris (CC) transports nutrients to retinal pigment epithelium (RPE) and photoreceptors and if the CC transport systems are dysregulated in the presence of too little or too much VEGF. This will be accomplished in mice using uniform size and charge gold nanoparticles, and labeled albumin and lipoprotein to evaluate caveolae, fenestrations, coated pits, and tight junction. CC transport will also be evaluated in mice lacking fenestrations and caveolae, or with deposits on Bruch's membrane. These results will be compared to transmission electron microscopy of a well-characterized cohort of AMD and aged subjects. These studies will determine mechanisms of CC transport and how they are affected in AMD, both of which are unknown.

描述（由申请人提供）：脉络膜毛细血管（CC）是一个小叶、有孔的血管系统，为RPE和光感受器提供所有氧气和血清营养。我们已经阐述了人类CC的诞生的血液血管生成和死亡的CC在湿性和干性AMD在最后一个赠款期。在干性AMD中，CC细胞死亡与邻近RPE的丧失有关。在湿性AMD中，CC的损失发生在脉络膜新生血管膜（CNV）形成之前，这是迄今为止无法解释的。我们已经观察到高浓度的血清蛋白周围CC在干性和湿性AMD。这种积累的原因和这些蛋白质对CC的影响尚不清楚。 虽然人们认为CC为RPE和光感受器提供营养并清除废物，但确切的运输机制尚不清楚。拟议的研究将通过开窗，小窝，和涂层坑CC的正常运输机制的特点。这些机制将使用确定尺寸的金纳米颗粒、标记的血清蛋白和标记的血清脂质进行评估。我们将通过使用缺乏caveolae（敲除cav-1，caveolae系统中的主要成分）或开窗（RPE产生的VEGF敲除或中和）的小鼠，或RPE过度表达VEGF或产生基底层沉积物的小鼠，确定CC转运的失调是否影响蛋白质蓄积。拟议的研究将确定布鲁赫膜沉积物对CC运输的影响和CC运输缺陷对存款形成的影响。 我们推测，CC转运功能障碍导致脉络膜中的血清蛋白积聚，这对CC具有毒性作用，可能是CC在AMD中死亡的原因。我们将在体外评价血清蛋白（白蛋白、CRP和α 2巨球蛋白（伴和不伴糖化））对脉络膜内皮细胞（CEC）的毒性，并确定这些血清蛋白是否导致CEC中紧密连接丧失、小窝或开窗数量变化。还假设CC功能障碍涉及AMD。我们的初步研究表明，开窗的损失与Bruchs膜沉积和RPE损失有关。在Greg Hageman为TEM准备的大量AMD眼睛中，我们将确定人类AMD中CC开窗、小窝、被膜凹陷和/或紧密连接是否发生变化，以及基底沉积物、玻璃疣和RPE损失与这些变化的相关性。 总之，该建议将定义CC用于向视网膜供应营养的正常运输过程。我们还将确定这些运输过程是否在AMD中改变。我们将确定随着年龄的增长，脉络膜中积累的血清蛋白质是否会导致我们在AMD中观察到的CC转运功能障碍和CC死亡。我们将研究如何减少或升高VEGF改变CC运输。这种关于CC转运及其在AMD中如何变化的新知识对于开发用于预防AMD中发生的视网膜变性和CNV的新的全身治疗性纳米颗粒将是非常宝贵的。 公共卫生关系：本研究将确定脉络膜毛细血管（CC）如何将营养物质转运到视网膜色素上皮（RPE）和光感受器，以及CC转运系统在VEGF过少或过多的情况下是否失调。这将在小鼠中使用均匀尺寸和电荷的金纳米颗粒以及标记的白蛋白和脂蛋白来完成，以评价小窝、开窗、包被的小窝和紧密连接。还将在缺乏开窗和小窝或Bruch膜上有沉积物的小鼠中评价CC转运。这些结果将与AMD和老年受试者的良好表征队列的透射电子显微镜进行比较。这些研究将确定CC转运的机制以及它们如何在AMD中受到影响，这两者都是未知的。