Endothelial glycocalyx reconstitution during sepsis

描述（由申请人提供）：自希波克拉底最初描述“腐败”以来，脓毒症已被认为是人类痛苦和死亡的主要原因。尽管在了解感染的全身炎症反应方面取得了重大进展，但脓毒症治疗的临床试验一再令人失望。这些失败强调了需要新的，多学科的观点到脓毒性器官损伤的发病，进展和解决。 内皮糖萼是衬在血管表面的一层糖胺聚糖和相关的蛋白聚糖。在体内，糖萼形成实质性的内皮表面层（ESL），其影响炎症、内皮渗透性和与脓毒症病理生理学高度相关的血管张力生物学过程。我们最近发现，肺ESL，通过调节内皮细胞表面粘附分子的暴露，起到控制中性粒细胞进入肺的守门功能。响应感染刺激，活化的内皮细胞切割肺ESL，允许中性粒细胞粘附和随后的外渗。从目的上讲，这种守门功能还需要对ESL重建进行精确的细胞控制，从而限制肺部炎症的程度。尽管与脓毒症患者的治疗相关，但这些ESL修复过程尚未探索。 我们假设，降解的肺ESL在其他健康小鼠中迅速重建，从而维持肺血管稳态。在脓毒症期间，ESL重建延迟，导致脓毒症肺损伤的过度肺部炎症和水肿特征。使用最先进的肺活体显微镜（E。施密特，肺/重症监护，科罗拉多大学）和糖（R。Linhardt，Chemistry，Rensselaer Polytechnic Institute）方法，我们建议（1）确定肺部ESL重建的潜在机制，（2）确定这些机制在脓毒症期间如何受到抑制，以及（3）治疗性地操纵这些机制以加速ESL重建并减轻脓毒症肺损伤。这些多学科的研究，代表了脓毒症领域内的一个高度新颖的合作，将通过脓毒症肺损伤的动物模型以及从严重脓毒症患者中获得的生物样本的分析来补充。 总之，这项提案提供了一个新的，多学科的观点败血症：ESL的完整性是一个关键的决定因素的发病和发展的败血症器官损伤。因此，研究ESL重建的过程可能会在危重疾病中发现新的治疗靶点，尽管经过数千年的研究，仍然缺乏临床有效的病理生理靶向治疗。

DESCRIPTION (provided by applicant): Since the original descriptions of "putrefaction" by Hippocrates, sepsis has been recognized as a major cause of human suffering and mortality. Despite major advances made in understanding the systemic inflammatory response to infection, clinical trials of sepsis therapeutics have been repeatedly disappointing. These failure highlight the need for new, multidisciplinary perspectives into the onset, progression, and resolution of septic organ injury. The endothelial glycocalyx is a layer of glycosaminoglycans and associated proteoglycans lining the vascular surface. In vivo, the glycocalyx forms a substantial endothelial surface layer (ESL) that influences inflammation, endothelial permeability, and vascular tone-biologic processes highly relevant to sepsis pathophysiology. We have recently identified that the pulmonary ESL, by regulating exposure of endothelial surface adhesion molecules, serves a gatekeeping function controlling neutrophil transit into the lung. In response to an infectious stimulus, activated endothelial cells cleave the pulmonary ESL, allowing neutrophil adhesion and subsequent extravasation. Teleologically, this gatekeeping function would additionally require precise cellular control of ESL reconstitution, thereby limiting the magnitude of pulmonary inflammation. These processes of ESL repair, despite therapeutic relevance to patients with sepsis, have been unexplored. We hypothesize that a degraded pulmonary ESL is rapidly reconstituted in otherwise-healthy mice, allowing for maintenance of pulmonary vascular homeostasis. During sepsis, ESL reconstitution is delayed, contributing to the excessive pulmonary inflammation and edema characteristic of septic lung injury. Using state-of-the-art pulmonary intravital microscopy (E. Schmidt, Pulmonary/Critical Care, University of Colorado) and glycomic (R. Linhardt, Chemistry, Rensselaer Polytechnic Institute) approaches, we propose to (1) determine the mechanisms underlying pulmonary ESL reconstitution, (2) identify how these mechanisms are suppressed during sepsis, and (3) therapeutically manipulate these mechanisms to accelerate ESL reconstitution and attenuate septic lung injury. These multidisciplinary investigations, representing a highly novel collaboration within the field of sepsis, will be complemented by animal models of septic lung injury as well as analyses of biologic samples obtained from humans with severe sepsis. In summary, this proposal offers a new, multidisciplinary perspective on sepsis: that ESL integrity is a critical determinant of the onset and progression of septic organ injury. Investigating processes of ESL reconstitution may therefore identify novel therapeutic targets in a critical illness that, despite millennia of study, still lacks a clinically-efficacious, pathophysiology-targeted treatment.