Fast volumetric imaging of oxygen delivery in the mouse brain at single red blood cell resolution

以单红细胞分辨率对小鼠大脑中的氧气输送进行快速体积成像

• 批准号: 10525881
• 负责人: Dan Fu
• 金额: $ 42.02万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-06-01 至 2024-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10525881
• 关键词: 3-Dimensional; Address; Aging; Alzheimer' s Disease; Area; Astrocytes; Biological Process; Blood Circulation; Blood Vessels; Blood capillaries; Blood flow; Body Weight; Brain; Brain Diseases; Brain imaging; Brain region; Caliber; Cells; Cerebrovascular Circulation; Collaborations; Complex; Consumption; Development; Dyes; Erythrocytes; Event; Fluorescence Microscopy; Fluorescent Dyes; Functional Magnetic Resonance Imaging; Functional disorder; Glucose; Goals; Hemoglobin; Human; Hyperemia; Image; Imaging Device; Imaging Techniques; Imaging technology; In Vitro; Individual; Ischemic Stroke; Lasers; Link; Malignant Neoplasms; Measurement; Measures; Metabolic; Methods; Microscope; Microscopy; Microvascular Dysfunction; Monitor; Mus; Nerve Degeneration; Neurodegenerative Disorders; Neurons; Optical Coherence Tomography; Optics; Oxygen; Oxyhemoglobin; Pathologic; Penetration; Pericytes; Physiology; Play; Process; Pulse Oximetry; Pump; Regulation; Resolution; Rest; Role; Scanning; Source; Speed; Surface; Techniques; Technology; Time; Traumatic Brain Injury; Vascular blood supply; absorption; brain cell; brain health; cerebral microinfarct; cerebral microvasculature; cerebral oxygenation; deoxyhemoglobin; hemodynamics; improved; in vivo; in vivo imaging; microscopic imaging; multiparametric imaging; neurovascular; neurovascular coupling; novel; optical imaging; prevent; public health relevance; ratiometric; relating to nervous system; response; submicron; temporal measurement; tool; two-photon

PROJECT SUMMARY/ABSTRACT The human brain represents 2% of the weight of the body, but consumes ~20% of the total energy at rest. All that energy – mostly in the form of glucose and oxygen - has to be delivered to the brain cells through an intricate network of microvessels, the majority of which are capillaries. Although it is well-known that increased neuronal activity in a region of the brain is associated with an increase in cerebral blood flow (functional hyperemia), the role of capillaries in blood flow regulation and oxygen delivery remains controversial. Nevertheless, capillary dysfunction has been suggested to play a crucial role in a wide variety of brain diseases and conditions, especially Alzheimer’s disease. To better understand capillary function and how it meets the widely varying energy demand of neurons, it is crucial to be able to measure oxygen delivery at high spatial and temporal resolution. Unfortunately, current technologies for imaging oxygen delivery, including intrinsic optical imaging, optical coherence tomography, and photoacoustic microscopy, have either limited spatial resolution or are incompatible with existing neuronal activity imaging. These limitations prevent a detailed understanding of the interaction between capillaries and neurons and how capillary dysfunction impacts brain function. To address this critical technological gap, we aim to develop a novel transient absorption microscopy technique that is capable of oxygen saturation (sO2) imaging at single red blood cell (RBC) resolution using intrinsic hemoglobin contrasts. This technique exploits a fundamentally different contrast mechanism from other optical approaches. It uses the transient absorption of endogenous hemoglobin molecules to image RBCs, and replies on excited- state dynamics difference between oxyhemoglobin and deoxyhemoglobin to determine sO2. Compared to the existing two-photon oxygen probe, our new technique potentially offers 3-4 orders of magnitude improvement in sO2 imaging speed. More importantly, it can be readily integrated with other high-throughput microvessel and neuron measurements. In Aim 1, we will develop and validate a high sensitivity transient absorption microscope for in vivo sO2 imaging of the brain cortex. A new dual-wavelength laser will be used to maximize sO2 sensitivity and imaging depth. Accuracy of sO2 imaging will be determined by comparison with an improved phosphorescent oxygen probe Oxyphor2. In Aim 2, we will create a high-throughput volumetric imaging microscope by combining TAM imaging with Bessel beam excitation and a novel interlaced scanning method. The new microscope will be optimized for simultaneous volumetric imaging of capillary sO2, vessel diameter, blood flow, flux, and neuronal activity. This breakthrough capability will enable real-time assessment of oxygen delivery through each capillary in the microvessel network at an unprecedented spatial and temporal resolution. We anticipate broad applications of this technology in studying neurovascular coupling, microvascular diseases, aging, and neurodegeneration.

项目概要/摘要 人脑占身体重量的 2%，但在休息时消耗约 20% 的总能量。 所有这些能量——主要以葡萄糖和氧气的形式——必须通过 复杂的微血管网络，其中大部分是毛细血管。尽管众所周知，增加 大脑某个区域的神经元活动与脑血流量（功能性血流量）的增加有关。 充血），毛细血管在血流调节和氧气输送中的作用仍然存在争议。 然而，毛细血管功能障碍被认为在多种脑部疾病中发挥着至关重要的作用 和病症，尤其是阿尔茨海默病。为了更好地了解毛细血管功能及其如何满足 神经元的能量需求差异很大，因此能够测量高空间和高空间的氧气输送至关重要 时间分辨率。不幸的是，当前用于成像氧气输送的技术，包括内在光学 成像、光学相干断层扫描和光声显微镜的空间分辨率有限或 与现有的神经元活动成像不兼容。这些限制阻碍了对 毛细血管和神经元之间的相互作用以及毛细血管功能障碍如何影响大脑功能。致地址 这一关键的技术差距，我们的目标是开发一种新颖的瞬态吸收显微镜技术 能够使用内在血红蛋白以单个红细胞 (RBC) 分辨率进行氧饱和度 (SO2) 成像 对比。该技术利用了与其他光学方法根本不同的对比度机制。 它利用内源性血红蛋白分子的瞬时吸收对红细胞进行成像，并响应激发的 氧合血红蛋白和脱氧血红蛋白之间的状态动力学差异来确定 sO2。相比于 与现有的双光子氧探针相比，我们的新技术可能将 SO2 成像速度。更重要的是，它可以很容易地与其他高通量微血管集成 神经元测量。在目标 1 中，我们将开发并验证高灵敏度瞬态吸收显微镜 用于大脑皮层的体内 sO2 成像。将使用新型双波长激光器来最大限度地提高 sO2 灵敏度 和成像深度。 sO2 成像的准确性将通过与改进的磷光成像进行比较来确定 氧气探头 Oxyphor2。在目标 2 中，我们将通过结合创建高通量体积成像显微镜 采用贝塞尔光束激励和新颖的隔行扫描方法进行 TAM 成像。新的显微镜将 针对毛细血管 sO2、血管直径、血流量、通量和神经元的同步体积成像进行了优化 活动。这一突破性的能力将能够实时评估通过每个毛细血管的氧气输送 以前所未有的空间和时间分辨率在微血管网络中。我们预计广泛 该技术在研究神经血管耦合、微血管疾病、衰老和 神经变性。