Background

Neutrophil extracellular traps (NETs) facilitate bacterial clearance but also promote thrombosis and organ injury in sepsis. We quantified ex vivo NET induction in septic humans and murine models of sepsis to identify signalling pathways that may be modulated to improve outcome in human sepsis.

Methods

NET formation in human donor neutrophils was quantified after incubation with plasma obtained from patients with sepsis or systemic inflammation (double-blinded assessment of extracellular DNA using immunofluorescence microscopy). NET formation (% neutrophils forming NETs) was correlated with plasma cytokine levels (MultiPlex assay). Experimental sepsis (caecal ligation and puncture or intraperitoneal injection of Escherichia coli) was assessed in C57/BL6 male mice. The effect of pharmacological inhibition of CXCR1/2 signalling (reparixin) on NET formation, organ injury (hepatic, renal, and cardiac biomarkers), and survival in septic mice was examined.

Results

NET formation was higher after incubation with plasma from septic patients (median NETs=25% [10.5–46.5%]), compared with plasma obtained from patients with systemic inflammation (14% [4.0–23.3%]; P=0.02). Similar results were observed after incubation of plasma from mice with neutrophils from septic non-septic mice. Circulating CXCR1/2 ligands correlated with NETosis in patients (interleukin-8; r=0.643) and mice (macrophage inflammatory protein-2; r=0.902). In experimental sepsis, NETs were primarily observed in the lungs, correlating with fibrin deposition (r=0.702) and lung injury (r=0.692). Inhibition of CXCR1/2 using reparixin in septic mice reduced NET formation, multi-organ injury, and mortality, without impairing bacterial clearance.

Conclusion

CXCR1/2 signalling-induced NET formation is a therapeutic target in sepsis, which may be guided by ex vivo NET assays.

中文翻译：

---

通过靶向 CXCR1/2 减少 NETosis 可减少实验性人和小鼠败血症的血栓形成、肺损伤和死亡率

背景

中性粒细胞胞外陷阱 (NETs) 有助于细菌清除，但也会促进脓毒症中的血栓形成和器官损伤。我们量化了脓毒症人类和鼠类脓毒症模型中的离体NET 诱导，以确定可以调节以改善人类脓毒症结果的信号通路。

方法

与从脓毒症或全身炎症患者获得的血浆孵育后，对人类供体中性粒细胞中的 NET 形成进行量化（使用免疫荧光显微镜对细胞外 DNA 进行双盲评估）。NET 形成（形成 NETs 的中性粒细胞百分比）与血浆细胞因子水平（MultiPlex 测定）相关。在 C57/BL6 雄性小鼠中评估了实验性败血症（盲肠结扎和穿刺或腹膜内注射大肠杆菌）。研究了 CXCR1/2 信号（瑞帕利辛）对 NET 形成、器官损伤（肝、肾和心脏生物标志物）和脓毒症小鼠存活率的药理学抑制作用。

结果

与来自全身炎症患者的血浆（14% [4.0-23.3%]； P = 0.02）相比，脓毒症患者血浆孵育后 NET 形成更高（中位数 NETs=25% [10.5-46.5%] ）。将来自小鼠的血浆与来自脓毒症非脓毒症小鼠的嗜中性粒细胞一起温育后观察到类似的结果。循环 CXCR1/2 配体与患者（白细胞介素 8；r =0.643）和小鼠（巨噬细胞炎症蛋白 2；r =0.902）的 NETosis 相关。在实验性脓毒症中，NETs 主要在肺中观察到，与纤维蛋白沉积 ( r =0.702) 和肺损伤 ( r=0.692）。在脓毒症小鼠中使用瑞帕辛抑制 CXCR1/2 可减少 NET 形成、多器官损伤和死亡率，而不会影响细菌清除。

结论

CXCR1/2 信号诱导的 NET 形成是脓毒症的治疗靶点，可以通过体外NET 检测来指导。