Imaging retinal astrocytes, ganglion cells and axonal transport in vivo

体内视网膜星形胶质细胞、神经节细胞和轴突运输成像

基本信息

批准号：
8114960
负责人：
BRAD FORTUNE
金额：
$ 19.13万
依托单位：
LEGACY EMANUEL HOSPITAL AND HEALTH CENTER
依托单位国家：
美国
项目类别：
财政年份：
2011
资助国家：
美国
起止时间：
2011-08-01 至 2013-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8114960
关键词：
Acute Animals Astrocytes Axon Axonal Transport Axotomy Bilateral Biological Assay Blindness Blood Blood Vessels Blood flow Cell Count Cells Chronic Chronic Disease Clinical Colchicine Data Diagnostic Procedure Disease Disease model Electroretinography Elements Evaluation Event Experimental Models Eye Functional disorder Future Glaucoma Gliosis Goals Homeostasis Human Image Imagery Imaging Techniques Individual Injection of therapeutic agent Injury Ischemia Laboratories Lasers Life Longitudinal Studies Maintenance Measurement Measures Methodology Methods Microtubules Modeling Nerve Crush Nerve Degeneration Neuroglia Nocodazole Ophthalmoscopy Optic Nerve Optical Coherence Tomography Outcome Patients Perfusion Physiologic Intraocular Pressure Physiological Play Primates Process Protocols documentation Rattus Research Research Personnel Retina Retinal Retinal Ganglion Cells Rodent Role Scanning Staging Structure System Techniques Thick Tissue Sample Tissues Toxic effect Tracer Translating United States Variant Vision axonal degeneration cell injury follow-up ganglion cell imaging modality in vivo nonhuman primate novel pressure prospective response response to injury retinal nerve fiber layer uptake

项目摘要

DESCRIPTION (provided by applicant): Astrocytes are a major class of glia in the vertebrate retina. They are located primarily within the innermost retinal layers; their processes surround retinal ganglion cell (RGC) axons and axon bundles as well as all blood vessels. Because of this anatomical relationship, and a variety of physiological evidence, astrocytes are thought to have a major role in the mechanisms of retinal blood flow autoregulation, i.e. the maintenance of nearly constant blood flow in response to variations of ocular perfusion pressure. Astrocytes are also thought to play an important role in the pathophysiology of many ocular diseases by responding to a variety of insults such as ischemia, increased intraocular pressure and neuronal degeneration in a manner that has been characterized as gliosis. Hence, the ability to image astrocytes in vivo could help to elucidate aspects of disease pathophysiology. Similarly, there is evidence to suggest that RGC axonal cytoskeletal components, specifically microtubules, are disrupted during the earliest stages of response to experimental injuries such as axotomy and experimental glaucoma. This disruption is significant because microtubules are the "tracks" upon which axonal transport is driven. Thus, if microtubule abnormalities develop early in response to injury, the resultant axonal transport disruption could exacerbate the injury and inhibit protective or rescue responses from achieving full potential. The overall goal of this R21 project is to develop the methods for imaging retinal astrocytes, RGCs, their axons and axonal transport in vivo. The specific objectives are as follows: Specific Aim 1: To establish methodologies for in vivo visualization of retinal astrocytes, RGCs, their axons and active axonal transport in the rat eye. To evaluate the optimal concentration, follow-up duration and persistence of in vivo markers as well as perform histopathological studies to corroborate in vivo observations. Specific Aim 2: To evaluate potential toxicity of in vivo astrocyte markers and axonal transport tracers using sensitive measures of retinal function (electroretinography, ERG) and retinal structure (spectral domain optical coherence tomography, SDOCT), so as to assess potential for use in primate experimental models. Specific Aim 3: To evaluate the sensitivity of our newly developed methods by comparing the impact of four unilateral experimental injury models (intravitreal injection of nocodazole/colchicine to disrupt axonal microtubules and inhibit active axonal transport; acute elevation of intraocular pressure; chronic elevation of intraocular pressure; and optic nerve crush) with results obtained in bilateral control eyes. The novel methods developed in this proposal will make possible in future proposals, studies about the onset of astrocyte abnormalities and RGC axonal transport abnormalities and comparisons of those phenomena to the course of RGC and axonal degeneration in experimental models of RGC injury. PUBLIC HEALTH RELEVANCE: Glaucoma is one of the most common causes of blindness in the United States and around the world. It is a chronic disease with no known cure. Though prospective longitudinal trials have found that treatment to lower intraocular pressure decreases the rate of progressive vision loss, some individuals continue to lose vision despite successful therapy to lower their intraocular pressure. Thus, a more thorough understanding of the events leading to damage and vision loss in glaucoma is required. The goal of this project is to develop methods for evaluating two groups of cells and aspects of their function in the living eye using specialized imaging techniques.

描述（由申请人提供）：星形胶质细胞是脊椎动物视网膜中的一类主要的神经胶质细胞。它们主要位于视网膜最内层；它们的突起围绕视网膜神经节细胞 (RGC) 轴突和轴突束以及所有血管。由于这种解剖关系以及各种生理学证据，星形胶质细胞被认为在视网膜血流自动调节机制中发挥着重要作用，即根据眼灌注压的变化维持几乎恒定的血流。星形胶质细胞还被认为在许多眼部疾病的病理生理学中发挥着重要作用，其以神经胶质增生的方式对多种损伤做出反应，例如缺血、眼内压升高和神经元变性。因此，体内星形胶质细胞成像的能力有助于阐明疾病病理生理学的各个方面。同样，有证据表明，RGC 轴突细胞骨架成分，特别是微管，在对实验性损伤（如轴索切除术和实验性青光眼）反应的最早阶段被破坏。这种破坏非常重要，因为微管是驱动轴突运输的“轨道”。因此，如果微管异常在损伤反应早期出现，由此产生的轴突运输中断可能会加剧损伤并抑制保护或救援反应充分发挥潜力。 R21 项目的总体目标是开发对视网膜星形胶质细胞、RGC、其轴突和体内轴突运输进行成像的方法。具体目标如下：具体目标1：建立大鼠眼中视网膜星形胶质细胞、RGC、其轴突和主动轴突运输的体内可视化方法。评估体内标记物的最佳浓度、随访持续时间和持久性，并进行组织病理学研究以证实体内观察结果。具体目标2：使用视网膜功能（视网膜电图，ERG）和视网膜结构（谱域光学相干断层扫描，SDOCT）的灵敏测量来评估体内星形胶质细胞标记物和轴突转运示踪剂的潜在毒性，从而评估在灵长类动物中使用的潜力实验模型。具体目标 3：通过比较四种单侧实验损伤模型（玻璃体内注射诺考达唑/秋水仙碱破坏轴突微管并抑制主动轴突运输；眼内压急性升高；眼内压慢性升高）的影响来评估我们新开发的方法的敏感性。压力；和视神经挤压），并在双侧对照眼中获得结果。本提案中开发的新方法将使未来的提案成为可能，研究星形胶质细胞异常和 RGC 轴突运输异常的发生，以及将这些现象与 RGC 损伤实验模型中的 RGC 和轴突变性过程进行比较。公共卫生相关性：青光眼是美国和世界各地最常见的失明原因之一。这是一种慢性疾病，目前尚无治愈方法。尽管前瞻性纵向试验发现，降低眼压的治疗可以降低进行性视力丧失的发生率，但尽管降低眼压的治疗取得了成功，一些人的视力仍继续丧失。因此，需要更彻底地了解导致青光眼损伤和视力丧失的事件。该项目的目标是开发使用专门的成像技术评估活体眼睛中两组细胞及其功能的方法。