Functional imaging of retinal photoreceptors

项目摘要：这是一个R 01更新，旨在开发功能性内在光信号（IOS）成像， 视网膜光感受器的生理学评估。视网膜光感受器是已知的主要目标， 年龄相关性黄斑变性（AMD）和色素性视网膜炎（RP）。及早发现眼疾 客观评估治疗效果是预防视力丧失和失明的重要步骤。 仅结构性生物标志物不能提供足够的信息用于评估视网膜的生理状况。 光感受器和组合功能测试经常需要用于疾病检测和治疗 考核然而，将结构和功能分开进行， 测量.功能性IOS成像，也称为视视网膜成像术（ORG）或视生理学，是基于 视网膜中刺激诱发的生理活动的近红外（NIR）光映射。因为IOS映像 基于视网膜图像的动态处理，它可以自然地提供结构信息， 传统眼底照相。在第一个赠款期间，我们已经证明了刺激诱发的IOS 视网膜光感受器外节的反应。快速光感受器-IOS发生后立即 视网膜刺激的开始，将其自身与内层视网膜处的及时延迟的IOS变化区分开。的 快速光感受器-IOS为光感受器生理学的客观ORG提供了独特的标记，而没有信号 后感光层的污染。我们建议在这里描述快速的生物物理机制 photoreceptor-IOS（aim 1）;并验证快速photoreceptor-IOS成像用于感光细胞的客观ORG 在人类受试者中的功能（目标2）。第一个目的是使用动物模型来验证快速的相关性。 光感受器-IOS到光转导的激活阶段。定制设计的混合共焦OCT 检眼镜将用于WT和rd 10小鼠中快速光感受器-IOS的体内表征。体外 将进行延时光学显微镜检查，以表征个体的瞬时外节反应。 光感受器比较电子显微镜的黑暗和光适应视网膜组织将实施 以验证在子盘级的光驱动外部段收缩。第二个目的是验证的可行性， 使用快速光感受器-IOS成像用于人光感受器的体内ORG的临床转化。我们有 最近展示了基于虚拟结构化检测（VSD）的单个杆的超分辨率成像， 在清醒的人身上。在本项目中，基于VSD的超分辨率检眼镜将得到改进， 实现μm级空间分辨率和ms级时间分辨率，用于成像快速感光器-IOS变化 在人类的光感受器中。这项研究的成功将为寻求临床应用铺平道路。 视网膜光感受器的客观ORG，使早期疾病诊断和及时治疗评估， AMD、RP和其他可能导致感光功能障碍的眼部问题。

Project summary: This is a R01 renewal to develop functional intrinsic optical signal (IOS) imaging for physiological assessment of retinal photoreceptors. Retinal photoreceptors are known as the primary target of both age-related macular degeneration (AMD) and retinitis pigmentosa (RP). Early detection of eye diseases and objective assessment of therapeutic outcomes are essential steps to prevent vision loss and blindness. Structural only biomarkers cannot provide enough information for evaluating physiological condition of retinal photoreceptors, and combined functional test is frequently required for disease detection and treatment assessment. However, it is time-consuming and costly inefficient to conduct separate structural and functional measurements. Functional IOS imaging, also termed as optoretinography (ORG) or optophysiology, is based on near infrared (NIR) light mapping of stimulus-evoked physiological activities in the retina. Because IOS imaging is based on dynamic processing of retinal images, it can naturally provide structural information offered in traditional fundus photography. During the first grant period, we have demonstrated stimulus evoked IOS response at the outer segment of retinal photoreceptors. The fast photoreceptor-IOS occurs immediately after the onset of the retinal stimulation, differentiating itself from timely delayed IOS changes at the inner retina. The fast photoreceptor-IOS provides a unique marker for objective ORG of photoreceptor physiology, without signal contamination of post-photoreceptor layers. We propose here to characterize biophysical mechanism of the fast photoreceptor-IOS (aim 1); and validate fast photoreceptor-IOS imaging for objective ORG of photoreceptor function in human subjects (aim 2). The first aim is to use animal models to verify the correlation of the fast photoreceptor-IOS to the activation phase of phototransduction. A custom-designed hybrid confocal-OCT ophthalmoscope will be used for in vivo characterization of fast photoreceptor-IOS in WT and rd10 mice. In vitro time-lapse light microscopy will be conducted to characterize transient outer segment response in individual photoreceptors. Comparative electron microscopy of dark- and light-adapted retinal tissues will be implemented to verify light-driven outer segment shrinkage at sub-disc level. The second aim is to verify the feasibility of clinical translation of using fast photoreceptor-IOS imaging for in vivo ORG of human photoreceptors. We have recently demonstrated virtually structured detection (VSD) based super-resolution imaging of individual rods and cones in awake human. During this project, the VSD based super-resolution ophthalmoscopy will be refined to achieve µm level spatial-resolution and ms level temporal-resolution for imaging fast photoreceptor-IOS changes in human photoreceptors. Success of this study will pave the way towards pursuing clinical application of objective ORG of retinal photoreceptors, enabling early disease diagnosis and prompt treatment assessment of AMD, RP and other eye problems which can cause photoreceptor dysfunctions.