LEUKOCYTE KINETICS IN THE MICROCIRCULATION

微循环中的白细胞动力学

• 批准号: 3736782
• 负责人: GEERT W SCHMID-SCHONBEIN
• 金额: --
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3736782
• 关键词: cell adhesion; cell death; cell migration; cellular pathology; electron microscopy; endotoxins; hemorrhagic shock; interleukin 1; laboratory rat; leukocyte activation /transformation; leukocytes; microcirculation; toxic shock syndrome; vascular endothelium; video recording system

The attachment of leukocytes to microvascular endothelium and migration into the interstitium is the hallmark of the inflammatory reaction that is especially deleterious in sepsis, shock, and episodes of ischemia/reperfusion. We have been able to demonstrate in previous studies that leukocyte entrapment in the microcirculation in the form of capillary plugging and post-capillary attachment to the endothelium constitutes a key facet of the disruption of tissue homeostasis. Our past studies, which were focused largely on intravascular events, will be expanded to explore the role of different leukocytes in tissue breakdown during the period of cell migration across the wall of microvessels and during amoeboid migration within the interstitium. Our proposed studies are designed to provide details of the key events during leukocyte mediated tissue injury, utilizing a newly developed digital fluorescent intravital microscopy approach in selected tissues of the rat. Our hypothesis proposes that activated leukocytes migrating in the tissue and activated endothelial cells serve as sources for free radical mediated tissue injury after stimulation. Fluorescent markers for peroxide formation, mitochondrial function and cell death will be utilized in conjunction with time-lapse microphotography to record sequential details of the events associated with leukocyte migration in the tissue. The membrane adhesion mechanisms (integrins and selectins) that are involved in interstitial migration will be investigated in the presence of selected stimulators. The mechanisms responsible for the production of oxygen free radicals and their consequences for parenchymal cell death will be quantified the first time in vivo at high optical resolution and identified. During the intravascular interaction between neutrophils and endothelial cells, peroxidation by iron catalyzed hydroxyl radical formation takes place in the region of close contact between the two cellular membranes. This mechanism will be explored in vivo under conditions where leukocytes are migrating into the interstitium in response to different proinflammatory stimulators. One observes regularly during migration of leukocytes across the microvascular wall, the development of micro-hemorrhagic erythrocyte diathesis and formation of interstitial pools of red cells. This phenomenon has been observed in many clinical situations but its underlying cellular and molecular mechanisms are unexplored. It is our hypothesis that formation of micro- hemorrhages requires an initial adhesion and diapedesis of leukocytes, and that red cell escape into the interstitium is associated with iron catalyzed hydroxyl radical formation and in turn enhanced parenchymal peroxidation and cell death. The mechanisms by which leukocytes in diapedesis form pores large enough for red cell escape will be investigated using intravital and electron microscopy in combination with modeling. The production of peroxides, cell death in the interstitium in the presence of micro-hemorrhages, and degeneration of connective tissue cells will be investigated utilizing digital fluorescent microscopy in vivo. A systematic program along these lines will serve to identify key mechanisms that lead to tissue damage in the presence of activated leukocytes and endothelial cells.

白细胞附着在微血管内皮和迁移 进入间质是炎症反应的标志 败血症，震惊和情节特别有害 缺血/再灌注。 我们已经能够在以前证明 研究白细胞在微循环中以 毛细管塞和毛细血管后的附件 构成组织稳态破坏的关键方面。 我们的过去 研究主要集中于血管内事件的研究将是 扩展以探索不同白细胞在组织分解中的作用 在细胞迁移的期间，微血管的壁和 在间质中的变形虫迁移期间。 我们提出的研究 旨在提供白细胞期间关键事件的详细信息 介导的组织损伤，利用新开发的数字荧光 大鼠选定组织中的静脉显微镜方法。 我们的 假设提出激活的白细胞在组织中迁移的白细胞和 活化的内皮细胞充当自由基介导的来源 刺激后的组织损伤。 过氧化荧光标记 形成，线粒体功能和细胞死亡将用于 与延时显微照片的结合以记录顺序细节 与白细胞迁移有关的事件。 这 涉及的膜粘附机制（整合素和选择蛋白） 在某些存在的情况下，将研究间隙迁移 刺激器。 负责生产无氧的机制 自由基及其对实质细胞死亡的后果将是 在高光学分辨率和 确定。 在中性粒细胞之间的血管内相互作用和 内皮细胞，铁催化的羟基过氧化 地层发生在两者之间的紧密接触区域 细胞膜。 该机制将在体内探索 白细胞迁移到间质中的条件 对不同促炎刺激剂的反应。 一个人定期观察 在白细胞迁移到微血管壁的过程中 微渗出型红细胞核心的发展和形成 红细胞的间质池。 在 许多临床情况，但其潜在的细胞和分子 机制是未开发的。 我们的假设是微观形成 出血需要白细胞的初始粘附和二子，并且 红细胞逃脱到间质中与铁有关 催化的羟基自由基形成和实质增强 过氧化和细胞死亡。 白细胞中的机制 二卵形形成足够大的毛孔，以进行红细胞逃生 使用插入和电子显微镜与 造型。 过氧化物的产生，细胞死亡中的间质死亡 微毛病的存在和结缔组织的变性 将使用数字荧光显微镜研究细胞 体内。 沿着这些行的系统程序将有助于识别密钥 在激活的情况下导致组织损伤的机制 白细胞和内皮细胞。