Background Burn shock caused by vascular leakage is one of the main causes of high mortality in severe burn injury. However, the pathophysiological mechanism of vascular leakage is still unclear. The purpose of this study was to explore the molecular mechanism of vascular leakage in the early stage of severe burn and provide a new target for the treatment of severe burns. Methods Neutrophils were isolated from human peripheral blood by magnetic beads sorting. ELISA was used to detect neutrophil-derived granule proteins and glycocalyx injury products in plasma. The vascular leakage and neutrophil movement were assessed by in vivo laser confocal imaging in mice, and high-quality video were provided. Adhesion-related molecules were investigated by qRT-PCR. The damage to glycocalyx of mice vascular endothelial cells was observed by transmission electron microscope and scanning electron microscope. Proteomic analysis, flow cytometry and immunofluorescence were used to further study the relationship between human peripheral blood neutrophil-derived hypochlorite (HOCl) and CD44 of human vascular endothelial cells. Results In this study, we found that rapidly increasing activated neutrophils secrete heparin binding protein (HBP) and myeloperoxidase (MPO) after severe burn injury. Increased HBP triggers vascular leakage with synergy of MPO, results in systemic edema and burn shock. Furthermore, we found that the MPO catalytic product HOCl but not MPO triggers CD44 extracellular domain shedding from vascular endothelial cells to damage the glycocalyx. Damage to the glycocalyx results in firm adhesion of neutrophils and increases vascular leakage. However, MPO inhibitors partially protect the glycocalyx of vascular endothelial cells. The combination of HBP and MPO inhibitors markedly reduces vascular leakage and systemic edema in the early stage of severe burns. Conclusions Taken together, these data reveal that neutrophil-derived HBP and MPO play an important synergies role in triggering vascular leakage at the early stage of severe burns. Targeted intervention in these two biomolecules may introduce new strategies for helping to reduce large amount of fluid loss and subsequent burn shock.

中文翻译：

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中性粒细胞衍生的肝素结合蛋白在严重烧伤早期触发血管渗漏并与髓过氧化物酶协同作用（附视频）

背景血管渗漏引起的烧伤休克是严重烧伤致死率高的主要原因之一。然而，血管渗漏的病理生理机制仍不清楚。本研究旨在探讨重度烧伤早期血管渗漏的分子机制，为重度烧伤的治疗提供新的靶点。方法采用磁珠分选法从人外周血中分离中性粒细胞。ELISA用于检测血浆中中性粒细胞衍生的颗粒蛋白和糖萼损伤产物。通过小鼠体内激光共聚焦成像评估血管渗漏和中性粒细胞运动，并提供高质量视频。通过qRT-PCR研究粘附相关分子。透射电镜和扫描电镜观察小鼠血管内皮细胞糖萼的损伤情况。采用蛋白质组学分析、流式细胞术和免疫荧光技术进一步研究人外周血中性粒细胞衍生次氯酸盐（HOCl）与人血管内皮细胞CD44的关系。结果在这项研究中，我们发现在严重烧伤后迅速增加的活化中性粒细胞分泌肝素结合蛋白 (HBP) 和髓过氧化物酶 (MPO)。增加的 HBP 与 MPO 的协同作用触发血管渗漏，导致全身水肿和烧伤休克。此外，我们发现 MPO 催化产物 HOCl 而不是 MPO 会触发 CD44 胞外结构域从血管内皮细胞脱落以破坏糖萼。糖萼的损伤导致中性粒细胞牢固粘附并增加血管渗漏。然而，MPO 抑制剂部分保护血管内皮细胞的糖萼。HBP 和 MPO 抑制剂的组合显着减少了严重烧伤早期的血管渗漏和全身水肿。结论 综上所述，这些数据表明，中性粒细胞衍生的 HBP 和 MPO 在重度烧伤早期触发血管渗漏中起重要的协同作用。对这两种生物分子的靶向干预可能会引入新的策略来帮助减少大量体液流失和随后的烧伤休克。HBP 和 MPO 抑制剂的组合显着减少了严重烧伤早期的血管渗漏和全身水肿。结论 综上所述，这些数据表明，中性粒细胞衍生的 HBP 和 MPO 在重度烧伤早期触发血管渗漏中起重要的协同作用。对这两种生物分子的靶向干预可能会引入新的策略来帮助减少大量体液流失和随后的烧伤休克。HBP 和 MPO 抑制剂的组合显着减少了严重烧伤早期的血管渗漏和全身水肿。结论 综上所述，这些数据表明，中性粒细胞衍生的 HBP 和 MPO 在重度烧伤早期触发血管渗漏中起重要的协同作用。对这两种生物分子的靶向干预可能会引入新的策略来帮助减少大量体液流失和随后的烧伤休克。