Intravitreal ECE-1 siRNA Treatment for Retinal Dysfunction during Early Diabetes

玻璃体内 ECE-1 siRNA 治疗早期糖尿病视网膜功能障碍

• 批准号: 8821045
• 负责人: TRAVIS W HEIN
• 金额: $ 21.98万
• 依托单位: TEXAS A&M UNIVERSITY HEALTH SCIENCE CTR
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8821045
• 关键词: Address; Advanced Development; American; Animal Model; Animals; Big Endothelin; Blindness; Blood Glucose; Blood Vessels; Blood flow; Cells; Clinical; Complications of Diabetes Mellitus; Cultured Cells; Data; Development; Diabetes Mellitus; Diabetic Retinopathy; Disease; Early treatment; Electroretinography; Endothelin-1; Endothelin-converting enzyme 1; Endothelium; Event; Eye; Eye diseases; Family suidae; Functional disorder; Goals; Human; Impairment; Insulin-Dependent Diabetes Mellitus; Ischemia; Mediating; Microcirculation; Modality; Modeling; Molecular; Molecular Target; Neural Retina; Neurons; Neurophysiology - biologic function; Nitric Oxide; Nutrient; Nutritional; Oxygen; Pathogenesis; Pathology; Physiological; Process; Production; Proteins; Regulation; Reporting; Resistance; Retina; Retinal; Retinal Diseases; Role; Site; Small Interfering RNA; Smooth Muscle; Staging; Streptozocin; System; Testing; Time; Treatment Protocols; United States; Vasoconstrictor Agents; Vasodilator Agents; Vasomotor; Vision; Visual impairment; animal model development; arteriole; constriction; diabetic; early onset; effective therapy; improved; in vivo; innovation; intravitreal injection; public health relevance; receptor; relating to nervous system; response; retinal damage; retinal ischemia; success; vasoconstriction

DESCRIPTION (provided by applicant): Retinopathy is a major complication of diabetes mellitus and a leading cause of blindness in the United States. Treatment modalities for restoring retinal function are relatively ineffective. Although alterations of both neural and vascular retina have been reported, the temporal relationship between neural retina damage and vasomotor dysfunction of resistance arterioles, the major site for blood flow regulation to the inner retina, remains unclear. This is important since reduced retinal blood flow occurs during early diabetes, which suggests that dysfunction of arterioles leading to ischemia may contribute to neural retina damage. However, mechanisms contributing to retinal vasomotor dysfunction in diabetes that are amenable to treatment prior to establishment of overt pathology remain unclear. Furthermore, development of an animal model of diabetes relevant to the human retinal microcirculation and its pathophysiology is lacking. To address these clinically important issues, we have developed a streptozocin-induced type 1 diabetes model in the pig, which we have shown resembles human in retinal vasomotor regulation/dysregulation. Our preliminary data show that within 2 wk of diabetes, endothelium-dependent nitric oxide (NO)-mediated dilation of retinal arterioles is impaired and constriction to big endothelin-1, the endothelin-1 (ET-1) precursor substrate for endothelin-converting enzyme- 1 (ECE-1), is enhanced without altering constriction to ET-1 per se. Although the smooth muscle response to ET-1 is unaltered, the ability to synthesize ET-1 is increased due to elevated ECE-1 expression. A potential harmful role for increased ET-1, besides its potent vasoconstrictor action, is its ability to inhibit NO production; however, whether ET-1 synthesis blockade can improve dilation during diabetes is unknown. Since retinal lactate level is increased within 2-wk diabetes and scotopic b-wave amplitude is reduced during 6-wk but not 2- wk diabetes, it appears vasomotor dysfunction promoting ischemia precedes inner neural retina damage. We recently detected ECE-1 in retinal arterioles but not neural retina, so ECE-1 may provide a specific vascular target for improving retinal arteriolar function, along with secondary amelioration of neural retina function, during early diabetes. Thus, the goal of this study is to understand the role of the ET-1 system in initiating retinal dysfunction by optimizing delivery of small interfering RNA (siRNA) via intravitreal injection to restore retinal arteriolar function. We will test the hypothesis that eary diabetes augments ECE-1 activity and ET-1 production leading to impairment of endothelium-dependent NO-mediated dilation of retinal arterioles prior to alteration of the neural retina function. To support the hypothesis and to test the feasibility of siRNA treatment, we will pursue the following specific aim: Determine whether molecular knockdown of ECE-1 in retinal arterioles improves diabetes-induced dysfunction of endothelium and neural retina. This innovative study will provide the first longitudinal assessment of both vascular and neural function in the retina from the same animal during diabetes, which will help in our understanding of retinal pathogenesis and development of new therapies for early treatment.

描述(申请人提供)：视网膜病变是糖尿病的主要并发症，也是美国致盲的主要原因。恢复视网膜功能的治疗方式相对无效。虽然已经报道了神经和血管视网膜的改变，但神经视网膜损伤和阻力小动脉血管运动障碍之间的时间关系是血流调节的主要部位。 内部视网膜，目前仍不清楚。这一点很重要，因为视网膜血流量减少发生在早期糖尿病期间，这表明导致缺血的小动脉功能障碍可能导致视网膜神经损伤。然而，导致糖尿病视网膜血管运动功能障碍的机制尚不清楚，这些机制可以在明确的病理建立之前进行治疗。此外，还缺乏与人类视网膜微循环及其病理生理学相关的糖尿病动物模型的开发。为了解决这些临床上的重要问题，我们建立了链脲佐菌素诱导的猪1型糖尿病模型，我们已经证明这种模型在视网膜血管运动调节/调节失调方面与人类相似。我们的初步数据显示，在糖尿病2周内，内皮依赖的一氧化氮(NO)介导的视网膜小动脉的扩张受到损害，对内皮素-1(ET-1)的前体底物--内皮素-1(ET-1)的收缩增强，而对ET-1本身的收缩没有改变。尽管血管对ET-1的反应没有改变，但合成ET-1的能力由于ECE1的表达增加而增加。增加ET-1的潜在有害作用，除了其强大的血管收缩作用外，还在于其抑制NO产生的能力；然而，ET-1合成阻断是否能改善糖尿病期间的扩张尚不清楚。由于糖尿病2周内视网膜乳酸水平升高，暗视b波波幅在6周糖尿病期间降低，但2周糖尿病未见明显变化，提示血管运动障碍促进缺血先于视网膜内神经损伤。我们最近在视网膜小动脉中检测到ECE1，但在神经视网膜中未检测到，因此ECE1可能为糖尿病早期改善视网膜小动脉功能以及神经视网膜功能的继发性改善提供一个特异的血管靶点。因此，本研究的目的是通过优化玻璃体内注射小干扰RNA(SiRNA)来恢复视网膜小动脉功能，了解ET-1系统在启动视网膜功能障碍中的作用。我们将验证这一假说，即早期糖尿病增加了ECE1的活性和ET-1的产生，导致内皮依赖的NO介导的视网膜小动脉在神经视网膜功能改变之前的扩张功能受损。为了支持这一假说并测试siRNA治疗的可行性，我们将追求以下特定目标：确定视网膜小动脉中ECE1的分子敲除是否改善了糖尿病引起的内皮和神经视网膜功能障碍。这项创新性的研究将首次对糖尿病期间同一动物视网膜的血管和神经功能进行纵向评估，这将有助于我们了解视网膜的发病机制，并为早期治疗开发新的治疗方法。