Venular leukocyte adhesion, impaired arteriolar vasoreactivity, and intestinal IR

小静脉白细胞粘附、小动脉血管反应性受损和肠道 IR

• 批准号: 7569377
• 负责人: RONALD JOHN KORTHUIS
• 金额: $ 37.04万
• 依托单位: UNIVERSITY OF MISSOURI-COLUMBIA
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-12-22 至 2010-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7569377
• 关键词: Accounting; Acetylcholine; Address; Adherence; Adhesions; Adhesives; Angiotensin II; Animal Model; Animals; Antioxidants; Arteries; Biological Availability; Blood Vessels; Blood flow; Cell Adhesion Molecules; Cell Degranulation; Chymase; Coupling; Data; Development; Emigrations; Endothelial Cells; Endothelium; Endothelium-Dependent Relaxing Factors; Event; Exhibits; Extravasation; Functional disorder; Gelatinase B; Genes; Infiltration; Intercellular adhesion molecule 1; Intestines; Ischemia; Ischemic Bowel Disease; Laboratories; Leukocyte Rolling; Leukocytes; Link; Mediating; Mesentery; Microscopic; Modeling; Mus; Nitric Oxide; Organ; Oxidases; P-Selectin; Pathogenesis; Pathology; Peptide Hydrolases; Permeability; Play; Reaction; Reactive Oxygen Species; Reagent; Relaxation; Reperfusion Therapy; Role; Shock; Signal Transduction; Small Intestines; Stimulus; Superoxide Dismutase; Superoxides; Testing; Tissues; Vasodilation; Work; arteriole; knockout animal; mast cell; novel; postcapillary venule; prevent; response

DESCRIPTION (provided by applicant): One of the earliest events in the pathogenesis of intestinal ischemia/reperfusion (I/R) is microvascular dysfunction that is characterized by leukocyte/endothelial cell adhesive interactions (LECA) in postcapillary venules and impaired endothelium-dependent, NO-mediated vasodilatory responses (EDO) in upstream arteries and arterioles. Even though leukocytes do not roll along, adhere to, or emigrate across arteriolar endothelium in postischemic intestine, recent work indicates that I/R- induced LECA in postcapillary venules is causally linked to EDO dysfunction in arterioles. However, the mechanisms coupling l/R-induced LECA in postcapillary venules and postischemic EDO dysfunction in upstream arterioles are unknown. Our overall hypothesis is that l/R-induced EDO dysfunction in arterioles occurs by a mechanism that is triggered by LECA in postcapillary venules and involves the formation of signals in the interstitium elicited by the proteolytic activity of emigrated leukocytes that induce mast cell-dependent formation of angiotensin II. Subsequent activation of NAD(P)H oxidase in the vascular wall leads to the formation of reactive oxygen species which inactivates NO, thereby impairing EDO in arterioles. We will test this hypothesis by determining: 1) whether LECA in postcapillary venules play an obligatory role in the development of EDO in upstream arterioles; 2) the contribution of leukocyte-derived proteases (eg, matrix metalloproteinase-9 (MMP-9)) to EDO in arterioles; and 3) whether EDO dysfunction in arterioles is due to mast cell-derived chymase-dependent formation of All. Intravital microscopic approaches will be used to examine arteriolar EDO, venular LECA, and mast cell responses to I/R. A number of gene knockout animal models (P-selectin-/-, CD11/CD18-/-, ICAM-1-/-, MMP-9-/-, mast cell-deficient mice) will be used to further explore the mechanisms of impaired EDO arterioles isolated from postischemic intestine. Collectively, these aims address a novel mechanism to explain the profound disturbance in, arteriolar vasoregulatory function in tissues subjected to I/R. This work will identify new links between LECA in postcapillary venules, signals generated in the interstitium by emigrated leukocytes, and EDO dysfunction in arterioles. Given the importance of the endothelium in regulating vascular tone, these fundamentally important findings have enormous implications for our understanding of blood flow dysregulation in conditions characterized by I/R.

描述（由申请人提供）：肠缺血/再灌注（I/R）发病机制中最早的事件之一是微血管功能障碍，其特征是毛细血管后微静脉中的白细胞/内皮细胞粘附相互作用（LECA）和内皮依赖性受损，上游动脉和小动脉中 NO 介导的血管舒张反应 (EDO)。尽管白细胞在缺血后肠道中不会沿着小动脉内皮滚动、粘附或迁移，但最近的研究表明，毛细血管后微静脉中 I/R 诱导的 LECA 与小动脉中的 EDO 功能障碍有因果关系。然而，毛细血管后微静脉中 L/R 诱导的 LECA 与上游小动脉缺血后 EDO 功能障碍的耦合机制尚不清楚。我们的总体假设是，L/R 诱导的小动脉 EDO 功能障碍是由毛细血管后微静脉中 LECA 触发的机制发生的，涉及由迁移白细胞的蛋白水解活性引起的间质中信号的形成，从而诱导肥大细胞依赖性形成血管紧张素II。随后血管壁中 NAD(P)H 氧化酶的激活导致活性氧的形成，从而使 NO 失活，从而损害小动脉中的 EDO。我们将通过确定以下内容来检验这一假设：1）毛细血管后微静脉中的 LECA 是否在上游小动脉中 EDO 的发育中发挥必然作用； 2)白细胞来源的蛋白酶(例如基质金属蛋白酶-9(MMP-9))对小动脉中EDO的贡献； 3)小动脉中的EDO功能障碍是否是由于肥大细胞衍生的糜酶依赖性All的形成所致。活体显微镜方法将用于检查小动脉 EDO、小静脉 LECA 和肥大细胞对 I/R 的反应。多个基因敲除动物模型（P-选择素-/-、CD11/CD18-/-、ICAM-1-/-、MMP-9-/-、肥大细胞缺陷小鼠）将用于进一步探讨其机制从缺血后肠道中分离出受损的 EDO 小动脉。总的来说，这些目标提出了一种新机制来解释 I/R 组织中小动脉血管调节功能的严重紊乱。这项工作将确定毛细血管后微静脉中的 LECA、迁移的白细胞在间质中产生的信号以及小动脉中的 EDO 功能障碍之间的新联系。鉴于内皮细胞在调节血管张力方面的重要性，这些具有根本意义的重要发现对于我们理解以缺血再灌注为特征的情况下的血流失调具有巨大的意义。