Effects of systemic disease on corneal epithelial pathophysiology

 描述(申请人提供)：糖尿病引起的眼部并发症在美国是导致失明的主要原因。在接下来的几十年里，由2型糖尿病(T2 DM)引起的并发症的患病率预计将上升，增加该疾病的经济负担。这项建议的目标是：(1)确定导致疼痛和通常难治性糖尿病角膜病变的病理生理机制；(2)确定用于在高危患者发病之前检测到的生物标志物。 威胁视力的眼病。这一提议将检验三个新的假说：(1)IGF-1和胰岛素通过调节杂交-R、IGF-1R和INSR而在质膜和细胞核中介导不同的事件。(2)炎症和氧化应激水平的增加，以及角膜神经营养支持的丧失，导致了杂交-R的异常表达和功能。(3)除了调节杂交受体外，泪液中IGF相关蛋白含量的变化也是识别T2 DM眼部重大病变风险的潜在生物标志物。我们将在以下三个目标中检验这些假说：目标1：(A)评估控制角膜上皮细胞杂交-R形成、胰岛素敏感性和GSK3β活性的特定因素。(B)确定混合-R、IGF-1R和INSR的核目标。目的2：(A)检测IGF-1、IGF-II、胰岛素和IGFBP3对角膜上皮细胞的影响 在炎症介质和高血糖诱导的氧化应激存在的情况下神经纤维丢失。(B)研究T2 DM对杂交受体介导的基因调控的影响，以及与糖尿病相关的角膜原位基底神经丛和终末上皮神经改变的相关性。目的：应用新型微量生化分析、体内共聚焦显微镜(IVCM)和角膜视网膜病变的临床标志物，探讨人类2型糖尿病患者泪液中胰岛素样生长因子-1(IGF-1)、胰岛素和胰岛素样生长因子-3(IGFBP3)水平与角膜和视网膜病变的关系。这些目标将通过体外培养模型、原位人体组织分析和体内临床研究相结合来实现，以研究T2 DM的病理生理效应如何影响角膜神经的形态、泪膜的生理学和角膜上皮。这将是第一次研究混合受体在糖尿病角膜病变中的作用。这些研究还提出了角膜疾病中局部胰岛素信号受损的新的生物学机制。其他实验室专注于糖尿病伤口愈合受损的研究。我们的重点是识别导致角膜损伤的关键机制，以及表征和验证泪膜衍生的生物标记物，这些生物标记物将允许早期介入方法来预防糖尿病相关的视力丧失。

 DESCRIPTION (provided by applicant): Ocular complications from diabetes are a leading cause of blindness in the United States. Throughout the next few decades, the prevalence of complications stemming from Type 2 Diabetes Mellitus (T2DM) is expected to rise, increasing the economic burden of the disease. The goals of this proposal are: (1) to define the pathophysiological mechanisms that result in painful and often refractory diabetic corneal disease and; (2) to identify biomarkers for use in detecting at-risk patients prior to the onset of sight threatening ocular disease. This proposal will test three novel hypotheses: (1) That IGF-1 and insulin mediate distinct events at the plasma membrane and in the nucleus through regulation of Hybrid-R, IGF-1R and INSR. (2) That increasing levels of inflammation and oxidative stress, and a loss of trophic support from corneal nerves, results in aberrant Hybrid-R expression and function. (3) That, in addition to regulating Hybrid-R, changes in the amount of IGF-related proteins in tears represent potential biomarkers to identify patients at-risk for significant ocular pathology in T2DM. We will test these hypotheses in the following three aims: Aim 1: (A) Evaluate specific factors that control Hybrid-R formation, insulin sensitivity and GSK3 beta activity in corneal epithelial cells. (B) Identify nuclear targets for Hybrid-R, IGF-1R, and INSR. Aim 2: (A) Test the effects of IGF-1, IGF-II, insulin, and IGFBP3 on corneal epithelial cells and nerve fiber loss in the presence of inflammatory mediators and hyperglycemia-induced oxidative stress. (B) Characterize the effects of T2DM on Hybrid-R mediated gene regulation and correlate with diabetes-related changes in the corneal subbasal nerve plexus and terminal epithelial nerves in situ. Aim 3: Determine whether tear levels of IGF-1, insulin and IGFBP3 in human patients with T2DM correlate with corneal and retinal pathology, using new quantitative microvolume biochemical assays, in vivo confocal microscopy (IVCM), and clinical markers of corneal and retinal disease. These aims will be accomplished using a combination of in vitro culture models, in situ human tissue analysis, and in vivo clinical studies to investigate how the pathophysiological effects from T2DM impacts the morphology of corneal nerves, the physiology of the tear film, and the corneal epithelium. These will be the first studies to investigate a rolefor the Hybrid-R in mediating corneal disease in diabetes. These studies also propose a novel biological mechanism for impaired local insulin signaling in corneal disease. Other laboratories are focused on impaired wound healing in diabetes. Our focus is on identifying key mechanisms that contribute to corneal damage; and characterizing and validating tear-film derived biomarkers that will allow for early, interventional approaches to prevent diabetes-related vision loss.