Liu Lu, Shao Yiming, Zhang Yixuan, Yang Yunxi, Huang Jiamin, Li Linbin, Sun Ran, Zhou Yuying, Su Yicheng, Sun Bingwei
School of Medicine, Jiangsu University, Zhenjiang 212001, Jiangsu Province, China.
Department of Burns and Plastic Surgery, Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou 215002, Jiangsu Province, China.
Burns Trauma. 2021 Sep 17;9:tkab030. doi: 10.1093/burnst/tkab030. eCollection 2021.
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.
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 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.
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.
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.
血管渗漏引起的烧伤休克是严重烧伤患者高死亡率的主要原因之一。然而，血管渗漏的病理生理机制仍不清楚。本研究的目的是探讨严重烧伤早期血管渗漏的分子机制，并为严重烧伤的治疗提供新靶点。
通过磁珠分选从人外周血中分离中性粒细胞。采用酶联免疫吸附测定（ELISA）检测血浆中中性粒细胞衍生的颗粒蛋白和糖萼损伤产物。通过激光共聚焦成像评估小鼠的血管渗漏和中性粒细胞运动，并提供高质量视频。采用实时定量聚合酶链反应（qRT-PCR）研究黏附相关分子。通过透射电子显微镜和扫描电子显微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进一步研究人外周血中性粒细胞衍生的次氯酸（HOCl）与人血管内皮细胞CD44之间的关系。
在本研究中，我们发现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）。HBP增加并与MPO协同作用引发血管渗漏，导致全身水肿和烧伤休克。此外，我们发现MPO催化产物HOCl而非MPO触发血管内皮细胞CD44胞外域脱落，从而损伤糖萼。糖萼损伤导致中性粒细胞牢固黏附并增加血管渗漏。然而，MPO抑制剂可部分保护血管内皮细胞的糖萼。HBP与MPO抑制剂联合使用可显著减少严重烧伤早期的血管渗漏和全身水肿。
综上所述，这些数据表明中性粒细胞衍生的HBP和MPO在严重烧伤早期引发血管渗漏中起重要协同作用。针对这两种生物分子的靶向干预可能为减少大量液体流失及后续烧伤休克引入新的策略。
