Functional imaging of retinal photoreceptors

描述(申请人提供)：许多眼科疾病，如老年性黄斑变性(AMD)、糖尿病视网膜病变(DR)和青光眼，都涉及视网膜光感受器和/或视网膜内神经元的病理变化。众所周知，不同的疾病可以针对不同的细胞类型。原则上，生理修饰必须发生在患病的细胞中， 在可检测到视网膜形态异常之前。因此，视网膜生理功能评估对于早期发现疾病和可靠的治疗管理具有重要意义。在阿拉巴马大学伯明翰分校(UAB)，我们开发了几种光学方法，包括功能光学相干断层扫描(OCT)和行扫描共焦显微镜，利用与视网膜刺激相关的瞬时内在光信号(IOS)变化来进行生理活动的光生理监测。我们建议在这里验证高分辨率(&lt；50m)的光感受器生理学的功能IOS图。该项目的成功可以更好地研究和诊断与眼部疾病相关的光感受器功能障碍，包括AMD，这是导致严重视力丧失和法定失明的主要原因。我们的初步研究发现，在一个遗传性光感受器退化的小鼠模型中，iOS异常，并证明了在体内共聚焦-IOS观察到单个青蛙的光感受器。快速共聚焦iOS成像为光感受器生理的功能检查提供了一种高分辨率的方法，同时提供了视网膜形态的信息。然而，在功能性IOS成像在临床应用之前，存在几个障碍：1)视网膜内的IOS机制尚不清楚；2)视杆系统和视锥系统的IOS成像方案尚未制定；3)IOS修饰与视网膜疾病之间的临床相关性尚未建立。这些问题将在我们这个项目的三个具体目标中得到解决。第一个目标是调查IOS的生理来源。混合共聚焦OCT显微镜将被用来在亚细胞分辨率下解剖光感受器和视网膜内细胞的IOS。对正常和天冬氨酸处理的视网膜的比较测量将被用来测试IOS的生理通路。第二个目标是开发用于视网膜光感受器功能IOS标测的刺激方案。我们预计，通过对视网膜适应和刺激的定量控制，可以实现局部(例如，50米)视杆和视锥功能的选择性标测，而不需要分辨单个的光感受器。第三个目标是建立功能性IOS成像的临床潜力。遗传性光感受器变性模型RD10，即C57BL/6J-Pde6brd10，将用于比较IOS、电生理和组织学研究。这项研究的成功标准是证明iOS成像可以在不晚于视网膜可检测到的结构变化的时间点及早检测到光感受器功能障碍。到了最后 在这个项目中，临床应用的最终成像模式(即共焦或OCT)将是 根据共焦和OCT-iOS图像的定量比较确定。

DESCRIPTION (provided by applicant): Many eye diseases, such as age-related macular degeneration (AMD), diabetic retinopathy (DR) and glaucoma, involve pathological changes in retinal photoreceptors and/or inner retinal neurons. It is well known that different diseases can target different cell types. In principle, physiological modification must occur in diseased cells, before detectable abnormality of retinal morphology. Therefore, functional evaluation of retinal physiology is important for early disease detection and reliable treatment management. At University of Alabama at Birmingham (UAB), we have developed several optical approaches, including functional optical coherence tomography (OCT) and line-scan confocal microscopy, to pursue optophysiological monitoring of physiological activities using transient intrinsic optical signal (IOS) changes correlated with retinal stimulation. We propose here to validate functional IOS mapping of photoreceptor physiology at high resolution (< 50 m). Success of this project can lead to better study and diagnosis of photoreceptor dysfunction associated with eye diseases, including AMD which is the leading cause of severe vision loss and legal blindness. Our preliminary study has revealed IOS abnormalities in one mouse model with inherited photoreceptor degeneration, and in vivo confocal-IOS observation of individual frog photoreceptors have been demonstrated. Fast confocal-IOS imaging promises a high-resolution method for functional examination of photoreceptor physiology, while simultaneously providing information of retinal morphology. However, before clinical deployments of the functional IOS imaging, there are several obstacles: 1) IOS mechanism in the retina is not clear; 2) IOS imaging protocol of rod and cone systems is not developed; 3) clinical relevance between IOS modification and retinal disease is not established. These problems will be tackled in our three specific aims of this project. The first aim is to investigate physiological sources of the IOS. A hybrid confocal-OCT microscope will be employed to dissect the IOS in the photoreceptor and inner retinal cells at sub-cellular resolution. Comparative measurement of normal and aspartate-treated retinas will be used to test physiological pathways of the IOS. The second aim is to develop stimulation protocol for functional IOS mapping of retinal photoreceptors. We anticipate that selective mapping of localized (e.g., 50 m) rod and cone functions can be achieved through quantitative controls of retinal adaptation and stimulation, without the requirement of resolving individual photoreceptors. The third aim is to establish clinical potential of functional IOS imaging. One inherited photoreceptor degeneration model rd10, i.e., C57BL/6J-Pde6brd10, will be used for comparative IOS, electrophysiological, and histological study. Success criterion of this study is to demonstrate that the IOS imaging allows early detection of photoreceptor dysfunction at the time point no later than detectable structural changes in the retina. By the end of this project, ultimate imaging modality (i.e., confocal or OCT) for clinical application will be identified based on quantitative comparison of confocal- and OCT-IOS images.