Development of a BBB model to study transendothelial cell migration

描述（由申请人提供）：体外再现脑血管节段的生理特征是一个关键问题。脑血管系统的充分建模可以显著地帮助理解机制和改善疾病的药理学，其中白细胞在脑血管系统中的迁移作用被证明。由于之前的支持（第一阶段），我们能够原型和测试驱动一个新的动态血脑屏障（DIV-血脑屏障）允许白细胞外渗的体外模型。我们最初的努力旨在以可重复的方式刺穿中空纤维；研究结果最近发表。我们发现，人工穿孔的中空纤维允许白细胞通过血脑屏障，以响应促炎刺激和血流动力学变化。我们还能够通过改变系统的流变参数（例如，改变剪切应力）来产生毛细血管-小静脉段。此外，我们最近开发了一种系统，可以机械地“拉伸”中空纤维，将孔隙大小增加到生理相关的~5¿m。控制牵引力作用于纤维的末端，扫描电镜显示拉伸纤维内的孔隙扩大。为了进一步利用这种新的血脑屏障模型提供的商业机会，我们提出以下II期具体目标：优化允许白细胞外渗的动态体外脑-脑血管毛细血管模型的性能。确定由具有不同跨壁渗透性的纤维组成的正常和病变毛细血管-小静脉段的白细胞外渗模式（来自目的1）。将这些DIV-血脑屏障模型与其他先进的体外血脑屏障模型的结果进行比较。我们将首先为多发性硬化症和癫痫的研究和药物开发量身定制DIV毛细血管-小静脉系统的使用。我们组建了一个多学科的研究人员和专家团队，研究白细胞在脑血管系统中的迁移。商业化计划中详细说明了其他临床相关场所。鉴于我们的初步结果和本申请中详细描述的验证性进展报告，同时考虑到新药的开发仍然是神经系统疾病治疗的主要问题，我们认为，旨在改善药物开发的强大成就记录和合理的实验设计的结合是该2期提案的基本方面。

DESCRIPTION (provided by applicant): Reproducing in vitro the physiological characteristics of brain vascular segments represents a critical issue. Adequate modeling of the cerebrovasculature could significantly help understand the mechanisms and improve the pharmacology of disease where a role for leukocytes migrating across the cerebrovasculature is demonstrated. Thanks to the previous support (Phase I) we were able to prototype and test drive a new dynamic in vitro model of the BBB (DIV- BBB) permissive for leukocyte extravasation. Our initial effort aimed at piercing hollow fibers in a reproducible manner; the results were recently published. We found that manually perforated hollow fibers allow leukocytes passage across the BBB in response to pro-inflammatory stimuli and hemodynamic changes. We were also able to produce a capillary-venule segment by varying the rheological parameters (e.g., changing the shear stress) of the system. In addition we recently developed a system to mechanically "stretch" the hollow fibers increasing the pore size up to the physiologically relevant size of ~5 ¿m. Controlled traction was applied to the end of the fibers and scanning electron microscopy showed enlarged pores within the stretched fiber. To further the commercial opportunity afforded by this new BBB model, we propose the following Phase II Specific Aims: To optimize the performance of a dynamic in vitro capillary-venules model of the brain cerebrovasculature permissive for leukocyte extravasation. To determine the pattern of leukocytes extravasation in control and diseased capillary-venules segments composed of fibers with different transmural permeability properties (from Aim 1). To compare the results obtained using these DIV- BBB models to other state-of-art in vitro BBB models. We will initially tailor the use of the DIV capillary-venules system to multiple sclerosis and epilepsy research and drug development. We have assembled a multi-disciplinary team of investigators and experts in the field of leukocyte migration across the cerebrovasculature. Additional clinically relevant venues are detailed in the Commercialization Plan. Given our preliminary results and the confirmatory progress report described in detail in this application, and given the fact that i the meantime development of new drugs has remained a major issue in the treatment of neurological diseases, we believe that the combination of a strong record of accomplishment and sound experimental design aimed at improving drug development are fundamental aspects of this Phase 2 proposal.