Aims Bacterial infection activates neutrophils to release neutrophil extracellular traps (NETs) in bacterial biofilms of periprosthetic joint infections (PJIs). The aim of this study was to evaluate the increase in NET activation and release (NETosis) and haemostasis markers in the plasma of patients with PJI, to evaluate whether such plasma induces the activation of neutrophils, to ascertain whether increased NETosis is also mediated by reduced DNaseI activity, to explore novel therapeutic interventions for NETosis in PJI in vitro, and to evaluate the potential diagnostic use of these markers. Methods We prospectively recruited 107 patients in the preoperative period of prosthetic surgery, 71 with a suspicion of PJI and 36 who underwent arthroplasty for non-septic indications as controls, and obtained citrated plasma. PJI was confirmed in 50 patients. We measured NET markers, inflammation markers, DNaseI activity, haemostatic markers, and the thrombin generation test (TGT). We analyzed the ability of plasma from confirmed PJI and controls to induce NETosis and to degrade in vitro-generated NETs, and explored the therapeutic restoration of the impairment to degrade NETs of PJI plasma with recombinant human DNaseI. Finally, we assessed the contribution of these markers to the diagnosis of PJI. Results Patients with confirmed PJI had significantly increased levels of NET markers (cfDNA (p < 0.001), calprotectin (p < 0.001), and neutrophil elastase (p = 0.022)) and inflammation markers (IL-6; p < 0.001) in plasma. Moreover, the plasma of patients with PJI induced significantly more neutrophil activation than the plasma of the controls (p < 0.001) independently of tumour necrosis factor alpha. Patients with PJI also had a reduced DNaseI activity in plasma (p < 0.001), leading to a significantly impaired degradation of NETs (p < 0.001). This could be therapeutically restored with recombinant human DNaseI to the level in the controls. We developed a model to improve the diagnosis of PJI with cfDNA, calprotectin, and the start tail of TGT as predictors, though cfDNA alone achieved a good prediction and is simpler to measure. Conclusion We confirmed that patients with PJI have an increased level of NETosis in plasma. Their plasma both induced NET release and had an impaired ability to degrade NETs mediated by a reduced DNaseI activity. This can be therapeutically restored in vitro with the approved Dornase alfa, Pulmozyme, which may allow novel methods of treatment. A combination of NETs and haemostatic biomarkers could improve the diagnosis of PJI, especially those patients in whom this diagnosis is uncertain.

中文翻译：

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失调的中性粒细胞胞外陷阱和止血生物标志物作为假体周围感染的诊断工具和治疗靶点。


目的 细菌感染激活中性粒细胞，在假体周围关节感染 (PJI) 的细菌生物膜中释放中性粒细胞胞外陷阱 (NET)。本研究的目的是评估 PJI 患者血浆中 NET 激活和释放 (NETosis) 和止血标志物的增加，评估此类血浆是否诱导中性粒细胞活化，以确定 NETosis 增加是否也由 NETosis 减少介导。 DNaseI 活性，探索体外 PJI NETosis 的新治疗干预措施，并评估这些标记物的潜在诊断用途。方法前瞻性招募107例假体手术术前患者，其中71例疑似PJI，36例因非脓毒症接受关节置换术的患者作为对照，并获得柠檬酸血浆。 PJI 在 50 名患者中得到证实。我们测量了 NET 标记物、炎症标记物、DNaseI 活性、止血标记物和凝血酶生成测试 (TGT)。我们分析了来自确诊 PJI 和对照的血浆诱导 NETosis 和降解体外产生的 NET 的能力，并探索了用重组人 DNaseI 修复 PJI 血浆降解 NET 损伤的治疗方法。最后，我们评估了这些标志物对 PJI 诊断的贡献。结果 确诊 PJI 的患者的 NET 标记物（cfDNA (p < 0.001)、钙卫蛋白 (p < 0.001) 和中性粒细胞弹性蛋白酶 (p = 0.022)）和炎症标记物（IL-6；p < 0.001）水平显着升高）在血浆中。此外，PJI 患者的血浆比对照组的血浆诱导显着更多的中性粒细胞活化 (p < 0.001)，与肿瘤坏死因子 α 无关。 PJI 患者血浆中 DNaseI 活性也降低 (p < 0.001），导致 NET 的降解显着受损（p < 0.001）。这可以通过重组人 DNaseI 治疗恢复到对照水平。我们开发了一个模型，以 cfDNA、钙卫蛋白和 TGT 起始尾作为预测因子来改进 PJI 的诊断，尽管单独使用 cfDNA 即可实现良好的预测并且更易于测量。结论 我们证实 PJI 患者血浆中 NETosis 水平升高。他们的血浆既诱导 NET 释放，又因 DNaseI 活性降低而导致降解 NET 的能力受损。这种情况可以通过已批准的 Dornase alfa Pulmozyme 在体外进行治疗性恢复，这可能会带来新的治疗方法。 NET 和止血生物标志物的结合可以改善 PJI 的诊断，特别是那些诊断不确定的患者。