Cellular Physiology of the Aqueous Outflow Pathway

房水流出途径的细胞生理学

• 批准号: 9144399
• 负责人: HAIYAN GONG
• 金额: $ 40.93万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-30 至 2017-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9144399
• 关键词: Acute; Affect; Agonist; Anatomy; Animal Model; Antihypertensive Agents; Aqueous Humor; Area; Blindness; Cattle; Cell Line; Cell physiology; Characteristics; Chronic; Connective Tissue; Cytoskeleton; Development; Devices; Disease; Disease Progression; Drainage procedure; Elements; Endothelial Cells; Endothelium; Event; Exhibits; Extracellular Matrix; Eye; Filtration; Glaucoma; Goals; Human; Image; Imaging Techniques; Intercellular Junctions; Knowledge; Measures; Medical; Monkeys; Morphology; Mus; Nature; Ocular Hypertension; Operative Surgical Procedures; Outcome; Pathogenesis; Pathway interactions; Perfusion; Physiologic Intraocular Pressure; Physiological; Play; Primary Open Angle Glaucoma; Research; Resistance; Rho-associated kinase; Risk Factors; Role; Secondary to; Site; Structure; Structure of sinus venosus of sclera; Testing; Time; Trabecular meshwork structure; Vacuole; Visual impairment; anterior chamber; aqueous; density; fluorophore; high intraocular pressure; insight; kinase inhibitor; mouse model; novel; novel strategies; novel therapeutics; ocular hypotensive; three dimensional cell culture; time use

DESCRIPTION (provided by applicant): Glaucoma is a leading cause of blindness worldwide. A primary risk factor for the development and progression of primary open-angle glaucoma (POAG) is elevation of the intraocular pressure (IOP), resulting from a rise in aqueous humor outflow resistance. To date, the cause of this elevated resistance in POAG remains unknown. Previous studies have shown that the majority of aqueous outflow resistance is localized near the inner wall endothelium of Schlemm's canal (SC) and the juxtacanalicular connective tissue (JCT). Giant vacuoles and pores, which are characteristic features of the endothelial cells of SC, have long been suspected to play a role in regulating outflow resistance. A significant reduction in the number of giant vacuoles and pores was found in POAG eyes. Abnormal accumulations of extracellular matrix (ECM) within the JCT were also found contributing to resistance in POAG, but their contribution to total outflow resistance remains unknown. Our long-term goal is to determine the mechanisms that regulate outflow resistance in normal eyes and how this is increased in POAG. One obstacle in studying outflow resistance is finding a parameter that can be applied to various species regardless of their outflow anatomy. Our group has recently found, in mouse, bovine, monkey and human eyes, that only a fraction of outflow pathways actively contribute to drainage and termed those areas of outflow as the effective filtration area (EFA). We have demonstrated that EFA increases with higher outflow facility after use of a Rho-kinase inhibitor and decreases after acute and chronic elevation of IOP in bovine, monkey and human eyes. Moreover, we found an inverse relationship between IOP and EFA using a hypotensive mouse model. These results suggest that EFA serves as a valuable indicator across varied species for outflow resistance and IOP. We developed a novel fluorophore guided imaging technique to increase our chances of identifying important morphological and cellular differences between areas with high and low flow that contribute to increased outflow resistance and the pathogenesis of POAG. Additionally, we are now able to view giant vacuole formations of SC endothelial cells in real time using a novel three- dimensional cell culture device. With these two novel approaches, we will test our hypothesis that interactions between SC endothelial cells and their underlying ECM modulate giant vacuole and pore formations, thereby regulating EFA and outflow resistance. Our specific aims are too; 1) Evaluate the inverse relationship between the EFA and IOP in ocular hypertensive animal models; 2) Define the inverse relationship between the EFA and the outflow resistance in normal and POAG human eyes and determine the role of SC endothelial cells and their underlying ECM in regulating EFA; 3) Determine the mechanisms by which SC endothelial cells and their underlying ECM regulate the outflow using a novel three-dimensional cell culture device with real-time imaging. The results of this study will provide new insights for a novel therapeutic strategy to lower IOP by targeting the trabecular meshwork, where the initial problem resides.

描述（由申请人提供）：青光眼是全球失明的主要原因。原发性开角型青光眼（POAG）发生和发展的主要危险因素是眼内压（IOP）升高，由房水流出阻力升高引起。迄今为止，POAG耐药性升高的原因尚不清楚。先前的研究表明，大部分水流出阻力位于Schlemm管（SC）内壁内皮和导管旁结缔组织（JCT）附近。巨泡和巨孔是SC内皮细胞的特征，长期以来一直被怀疑在调节流出阻力中起作用。在POAG眼中发现巨大液泡和毛孔的数量显著减少。JCT内细胞外基质（ECM）的异常积累也被发现有助于POAG的阻力，但它们对总流出阻力的贡献尚不清楚。我们的长期目标是确定正常眼睛中调节流出阻力的机制，以及POAG如何增加流出阻力。研究流出阻力的一个障碍是寻找一个可以适用于各种物种的参数，而不考虑它们的流出解剖结构。我们的研究小组最近发现，在小鼠、牛、猴子和人类的眼睛中，只有一小部分流出通道积极地促进排水，并将这些流出区域称为有效过滤区域（EFA）。我们已经证明，在使用rho激酶抑制剂后，EFA随着流出设施的增加而增加，而在牛、猴和人眼的急性和慢性IOP升高后，EFA减少。此外，我们在低血压小鼠模型中发现IOP与EFA呈反比关系。这些结果表明，EFA可以作为不同物种流出阻力和IOP的有价值的指标。我们开发了一种新的荧光团引导成像技术，以增加我们识别高流量和低流量区域之间重要的形态学和细胞差异的机会，这些差异有助于增加流出阻力和POAG的发病机制。此外，我们现在能够使用一种新的三维细胞培养装置实时观察SC内皮细胞的巨液泡形成。通过这两种新方法，我们将验证我们的假设，即SC内皮细胞与其潜在的ECM之间的相互作用可以调节大液泡和孔的形成，从而调节EFA和流出阻力。我们的具体目标也是如此；1)评价高眼压动物模型EFA与IOP的负相关关系；2)明确正常和POAG人眼EFA与流出阻力的反比关系，确定SC内皮细胞及其底层ECM在调节EFA中的作用；3)利用具有实时成像功能的新型三维细胞培养装置，确定SC内皮细胞及其潜在的ECM调节流出的机制。这项研究的结果将为一种新的治疗策略提供新的见解，通过针对最初问题所在的小梁网来降低IOP。