Blood-Brain Barrier in Cerebral Ischemia

脑缺血中的血脑屏障

基本信息

批准号：
6630370
负责人：
Martha E O'Donnell
金额：
$ 28.22万
依托单位：
UNIVERSITY OF CALIFORNIA AT DAVIS
依托单位国家：
美国
项目类别：
财政年份：
2002
资助国家：
美国
起止时间：
2002-08-01 至 2006-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/6630370
关键词：
apical membrane blood brain barrier brain circulation brain edema cerebral ischemia /hypoxia chloride ion hypoxia immunoelectron microscopy ion transport laboratory rat microcirculation neurophysiology nuclear magnetic resonance spectroscopy sodium ion sodium potassium exchanging ATPase tissue /cell culture vasopressins

项目摘要

DESCRIPTION (provided by applicant): The long term goal of this project is to identify blood-brain barrier (BBB) ion transporters that mediate ischemia induced brain edema, a major cause of brain damage in stroke. During the early hours of cerebral ischemia, brain edema formation occurs in the presence of an intact BBB. In this process, BBB endothelial cells transport Na and Cl from blood into brain interstitium, with osmotically obliged water following. The specific ion transporters responsible are unknown, however BBB luminal Na and Cl transporters appear to play a key role. Much evidence indicates that hypoxia, which rapidly develops during ischemia, aglycemia occurring as glucose is depleted, and also centrally-released vasopressin are mediators of ischemia-induced brain edema formation. A novel aspect of this proposed project is the preliminary finding that a Na-K-Cl cotransporter appears to be localized in the luminal membrane of brain microvessel endothelial cells and that vasopressin, hypoxia and aglycemia stimulate activity of the cotransporter. This has led to the central hypothesis that a Na-K-Cl cotransporter, located at the luminal membrane of the BBB, is stimulated during ischemia to increase transport of Na and Cl with osmotically obliged water from blood to brain, causing edema formation. The present project has three specific aims. The first aim is to test the hypothesis that Na-K-Cl cotransport is present in luminal membranes of cerebral microvascular endothelial cells (CMEC). These studies will evaluate bovine brain microvessel luminal and abluminal membrane preparations for cotransport activity by radioisotopic flux analyses. Also, the in situ distribution of the cotransporter will be examined by immunoelectron microscopy of brain sections. The second aim is to test the hypothesis that Na-K-CI cotransport of BBB endothelial cells is stimulated by agents that mediate ischemia-induced cerebral edema. Here, the effects of hypoxia, aglycemia and vasopressin on cotransport activity will be examined in cultured human and bovine CMEC and freshly isolated bovine cerebral microvessels. The third aim is to test the hypothesis that inhibition of Na-K-Cl cotransport activity attenuates ischemia-induced brain edema. To do this, the effect of inhibiting the cotransporter on ischemia-induced changes in rat brain Na and water will be examined by nuclear magnetic resonance methods, which allow in vivo changes in brain Na and water to be followed in real time. The proposed studies should reveal whether therapeutic approaches aimed at blocking BBB Na-K-Cl cotransporter activity may be of value for attenuating ischemia-induced brain edema.

描述（由申请人提供）：该项目的长期目标是识别介导缺血引起的脑水肿的血脑屏障（BBB）离子转运蛋白，这是中风中脑损伤的主要原因。在脑缺血的凌晨，在完整的BBB存在下发生了脑水肿的形成。在此过程中，BBB内皮细胞将Na和Cl从血液转移到脑间质中，随后具有渗透性的水。负责的特定离子转运蛋白未知，但是BBB腔内NA和CL转运蛋白似乎起着关键作用。大量证据表明，缺血在缺血期间迅速发展，随着葡萄糖的耗尽而发生的ag糖症，并且中央发出的加压素是缺血诱导的脑水肿形成的介体。该提出的项目的一个新方面是初步发现，即Na-k-Cl共转运蛋白似乎位于脑微血管内皮细胞的腔膜中，而加压素，缺氧和高糖症刺激了Cotransporter的活性。这导致了一个中心假设：在缺血期间，位于BBB腔膜的Na-k-CL共转移蛋白被刺激以增加Na和Cl的转运，并用渗透义务从血液到脑的水从血液到脑，从而导致水肿形成。本项目具有三个具体目标。第一个目的是检验以下假设：脑微血管内皮细胞（CMEC）的腔膜中存在Na-k-Cl共同运动。这些研究将通过放射性药物通量分析评估牛脑微血管腔和空白膜制剂，以进行共同运动活性。同样，将通过脑切片的免疫电子显微镜检查共转运蛋白的原位分布。第二个目的是检验以下假设：BBB内皮细胞的Na-k-CI共同运动受到介导缺血诱导的脑水肿的刺激的刺激。在这里，将在培养的人和牛CMEC以及新鲜分离的牛脑微血管中检查缺氧，高血糖素和加压素对共转运活性的影响。第三个目的是检验抑制Na-K-CL共转运活性减弱缺血诱导的脑水肿的假设。为此，将通过核磁共振方法研究抑制局部孢子虫诱导的大鼠脑Na和水变化的影响，从而可以实时遵循脑Na和水的体内变化。拟议的研究应揭示旨在阻止BBB Na-K-CL共转运蛋白活性的治疗方法对于减弱缺血诱导的脑水肿可能是有价值的。