Retinal blood barrier permeability using optical tracers

微血管内皮的一个关键功能是维持液体和溶质转运的屏障。视网膜血管系统的破坏是包括糖尿病视网膜病变和年龄相关性黄斑变性在内的一些重要眼部疾病的定义特征。我们建议开发双示踪荧光血管造影作为一种新的定量工具，评估视网膜血管通透性。这项生物工程研究资助提案的设计确定了这项新技术的具体特点，以供进一步开发和测试。这种双示踪剂荧光血管造影技术通过大小荧光示踪剂的差异转运来量化视网膜血管的渗透性。我们已经在大鼠中使用示踪剂对荧光素钠（376D）和德克萨斯红葡聚糖（70kD）以及在较少的动物中使用试卤灵（235D）和FITC葡聚糖（2，000kD）实施了这种视网膜成像技术。我们已经获得了初步诱导甘露醇输注5分钟。提出了三个进一步研究的目标。首先，我们计划确定最好的囊内和经血管示踪剂的视网膜微循环的渗透性在体内测量。其次，我们建议开发光学仪器和图像分析技术，用于同时测量视网膜血管中的两种荧光示踪剂。第三，我们计划开发数学模型，用于从视网膜循环入口和出口处的荧光示踪剂的动力学识别视网膜微循环通透性特征。我们将使用简化的物理模型，数学模型，主要是体内大鼠研究来实现这些目标。我们的总体目标是开发这种方法作为测量视网膜渗透性的工具，其可以应用于诊断和跟踪这种重要的临床视网膜病理学的治疗效果，这是许多眼部疾病的特征。

A key function of the microvascular endothelium is maintenance of barrier against fluid and solute transport. Breakdown of the retinal vasculature is a defining feature of some significant ocular diseases including diabetic retinopathy and age related macular degeneration. We propose to develop dual tracer fluorescence angiography as a novel quantitative tool for assessing retinal vascular permeability. The design of this Bioengineering Research Grant proposal identify specific features of this new technique for further development and testing. This dual tracer fluorescence angiography technique quantifies the permeability of the retinal vasculature by differential transport of small and large fluorescent tracers. We have implemented this retinal imaging technique in rats using the tracer pairs sodium fluorescein (376D) & Texas Red dextran (70kD) and, in fewer animals, using resorufin (235D) & FITC dextran (2,000kD). We have obtained preliminary induced by 5 minutes of mannitol infusion. Three aims for further studies are proposed. First, we plan to identify the best intravesicular and transvascular tracers for in vivo measurement of the permeability of the retinal microcirculation. Secondly, we propose to develop optical instrumentation and image analysis techniques for the simultaneous measurement of two fluorescent tracers in retinal vessels. And thirdly, we plan to develop mathematical models for the identification of retinal microcirculatory permeability characteristics from the dynamics of fluorescent tracers at the inlet and outlet of the retinal circulation. We will use simplified physical models, mathematical models, and principally, in vivo rat studies to carry out these aims. Our overall goal is to develop this methodology as a tool to measure retinal permeability which can be applied to diagnose and track the efficacy of treatments of this significant clinical retinal pathology which is a characteristic feature of many ocular diseases.