Two-photon Imaging of Oxygen and Blood Flow in Retinal and Cerebral Vasculature

项目摘要/摘要 高分辨率成像技术对于研究肿瘤的发病机制和发展具有重要意义。 脑部小血管疾病(SVD)的治疗和筛查策略，包括阿尔茨海默病(AD) 和AD相关的痴呆症。以前的研究已经证明视网膜和大脑之间存在联系 微血管改变。此外，视网膜组织的可访问性为非侵入性成像提供了 在识别SVD所致微血管功能障碍方面的优势。然而，在我们的国家中仍然存在着一个重大差距 了解皮层和视网膜毛细血管网络在两种情况下是如何相互映射的 老龄化和SVD进展。填补这一空白需要创新技术来测量绝对微血管 视网膜和皮质毛细血管下尺度的氧合、灌流和形态，应用于动物模型 它概括了微血管病变的临床和组织病理学特征。 我们建议开发新的方法来研究视网膜氧气的输送和消耗，这是前所未有的 空间分辨率并关联在视网膜和皮质微血管系统中平行发生的变化 正常衰老和AD。AIM 1将开发并验证一种多模式双光子荧光成像方法 用于联合测量主要视网膜血管的绝对氧分压(PO2)和血流量，并推导出 氧气代谢率的全球测量。然后，我们将研究正常衰老对微血管的影响 皮质和视网膜组织的结构和功能。AIM 2将开发和验证自适应光学双光子 视网膜毛细血管中PO2的显微成像方法，结合毛细血管红细胞成像 (RBC)通量使用先前建立的RBC传代方法。高分辨率视网膜组织氧分压成像 还将开发PO2在血管系统和组织中的深度差像差成像。目标3 将检验微血管血流动力学和组织代谢变化在早期阶段的假说 AD在视网膜和大脑皮层平行发生。我们将比较视网膜和皮质微血管的氧合作用， 实验性阿尔茨海默病模型小鼠的血流量和氧代谢率。 研究视网膜氧气输送和消耗的新方法的发展将促进我们对 在正常衰老和SVD进展期间，皮质和视网膜同时存在微血管功能障碍， 在评估眼部疾病动物模型的视网膜微血管域方面提供了广泛的实用性，并增强了 对进行性神经退行性变和认知障碍血管机制的共同认识 在阿尔茨海默病和相关痴呆症中，SVD的形式也是如此。

PROJECT SUMMARY/ABSTRACT High-resolution imaging techniques are essential for investigation of the pathogenesis and development of therapeutic and screening strategies for cerebral small vessel disease (SVD), including Alzheimer Disease (AD) and AD-related dementias. Previous studies have demonstrated a link between retinal and cerebral microvascular changes. Moreover, the accessibility of the retinal tissue for noninvasive imaging offers an advantage for identifying microvascular dysfunction due to SVD. However, a significant gap remains in our understanding how changes in the capillary networks in cortex and retina mirror each other during both normal ageing and SVD progression. Filling the gap requires innovative technologies to measure absolute microvascular oxygenation, perfusion, and morphology at subcapillary scale in both retina and cortex, applied to animal models that recapitulate the clinical and histopathological features of microvasculopathy. We propose to develop novel methods to investigate retinal O2 delivery and consumption with unprecedented spatial resolution and to correlate changes that occur in parallel in retinal and cortical microvasculature during normal ageing and AD. Aim 1 will develop and validate a multimodal two-photon fluorescence imaging method for combined measurements of absolute oxygen tension (pO2) and blood flow in major retinal vessels and derive global measurements of O2 metabolic rate. We will then investigate how normal aging affects microvascular structure and function in cortical and retinal tissue. Aim 2 will develop and validate an adaptive optics two-photon microscopy imaging method for pO2 in the retinal capillaries, coupled with imaging of capillary red blood cell (RBC) flux using the previously established RBC passage method. High-resolution retinal tissue pO2 imaging will also be developed, as well as a deep Differential Aberration imaging of pO2 in vasculature and tissue. Aim 3 will test the hypothesis that microvascular hemodynamic and tissue metabolic changes during early stages of AD occur in parallel in retina and cerebral cortex. We will compare retinal and cortical microvascular oxygenation, blood flow, and O2 metabolic rate in experimental mouse model of AD. Development of novel methods to investigate retinal O2 delivery and consumption will advance our understanding of the concurrent microvascular dysfunction in cortex and retina during both normal ageing and SVD progression, provide broad utility in assessing retinal microvascular domains in animal models of eye disorders, and augment knowledge of vascular mechanisms of progressive neurodegeneration and cognitive impairment in common forms of SVD as well as in AD and related dementias.