PLASMA FIBRONECTIN AND LUNG VASCULAR PERMEABILITY

血浆纤连蛋白和肺血管通透性

• 批准号: 2734370
• 负责人: THOMAS G SABA
• 金额: $ 22.81万
• 依托单位: ALBANY MEDICAL COLLEGE
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-07-01 至 2001-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2734370
• 关键词: bacterial disease; biological signal transduction; extracellular matrix; fibronectins; gene expression; integrins; lung; postoperative complications; pulmonary edema; sheep; tumor necrosis factor alpha; vascular endothelium permeability

Plasma fibronectin deficiency often exists in septic surgical, trauma and burn patients with altered lung vascular permeability. This plasma fibronectin (Fn) deficiency may contribute to the etiology of decreased endothelial integrity and pulmonary edema. Plasma Fn incorporates into the extracellular matrix (ECM) of the lung where it influences cell-matrix interactions and endothelial protein permeability, in part, by its interaction with endothelial cell surface integrins. The investigators have demonstrated that infusion of purified human plasma Fn into sheep followed by its incorporation into the lung ECM prior to post- operative gram negative i.v. bacterial challenge will prevent the increase in lung protein permeability. The is vivo observation could also be "modeled" in vitro using confluent lung endothelial cell monolayers treated with TNF, which results in an increase in protein permeability and a disruption of the Fn containing matrix. Addition of purified human Fn to the medium could also prevent the TNF-alpha induced increase in endothelial monolayer permeability similar to the in vivo response, if the added plasma Fn incorporates into the subendothelial matrix. The investigators hypothesize that the TNF- alpha induced increase in lung permeability is mediated by either decreased expression of a5b1 Fn integrins on endothelial cells an/or disruption of the Fn matrix due to protease release from endothelial cells. It is also hypothesized that the protective and potentially therapeutic effects of Fn on lung endothelial permeability is due to its rapid incorporation into the ECM where it provides additional RGD cell attachment sites, improves endothelial adhesion, and influences endothelial cell spreading via an integrin-mediated signal transduction process. It is proposed to use the lung lymph fistula model in sheep to determine if the increase in lung endothelial permeability caused by post-operative bacteremia can be reversed by infusion of purified PFN; and the in vitro bovine lung endothelial cell monolayer model to define the mechanism of the TNF-alpha induced increase in protein permeability. The investigators will also determine if reversal of the increased permeability accomplished by the ECM incorporation of human plasma Fn requires an integrin mediated signal transduction event triggered by a reestablished association of a5b1 integrins with human Fn incorporated into the matrix. Determining the mechanism by which plasma Fn incorporation into the lung matrix influences its vascular integrity offers a basis for developing a novel approach to treat lung vascular failure and pulmonary edema in septic surgical and trauma patients.

血浆纤连蛋白缺乏通常存在于化脓性手术、创伤和 烧伤患者肺血管通透性改变。 这种等离子体 纤连蛋白（Fn）缺乏可能是导致纤维连接蛋白（Fn）减少的原因 内皮完整性和肺水肿。 血浆 Fn 包含 进入肺部的细胞外基质（ECM）并对其产生影响 细胞-基质相互作用和内皮蛋白通透性部分通过 它与内皮细胞表面整合素的相互作用。 调查人员 已经证明将纯化的人血浆 Fn 输注到 羊，然后将其纳入肺 ECM 之前，后 手术革兰氏阴性静脉注射细菌挑战将阻止 肺蛋白通透性增加。 体内观察可以 也可以使用汇合的肺内皮细胞进行体外“建模” 用 TNF 处理的单层细胞，导致蛋白质含量增加 渗透性和含 Fn 基质的破坏。 添加 将纯化的人 Fn 添加到培养基中也可以预防 TNF-α 诱导内皮单层通透性增加，类似于 体内反应，如果添加的血浆 Fn 融入 内皮下基质。 研究人员推测 TNF- α 诱导的肺通透性增加是由以下任一介导的 内皮细胞上 a5b1 Fn 整合素的表达减少和/或 由于内皮细胞释放蛋白酶而破坏 Fn 基质 细胞。 还假设保护性和潜在的 Fn 对肺内皮通透性的治疗作用是由于其 快速融入 ECM，提供额外的 RGD 细胞附着位点，改善内皮粘附，并影响 内皮细胞通过整合素介导的信号转导进行扩散 过程。 拟采用绵羊肺淋巴瘘模型 确定肺内皮细胞通透性增加是否由以下原因引起 术后菌血症可以通过输注纯化的 PFN 来逆转； 以及体外牛肺内皮细胞单层模型 定义 TNF-α 诱导蛋白质增加的机制 渗透性。 调查人员还将确定是否逆转 通过 ECM 掺入实现增加渗透性 人血浆 Fn 需要整合素介导的信号转导 由 a5b1 整合素重建关联触发的事件 人Fn并入基质中。 确定机制 血浆 Fn 掺入肺基质影响其 血管完整性为开发新方法奠定了基础 治疗脓毒症手术中的肺血管衰竭和肺水肿 外伤患者。