Complex pleural space infections often require treatment with multiple doses of intrapleural tissue plasminogen activator (tPA) and deoxyribonuclease, with treatment failure frequently necessitating surgery. Pleural infections are rich in neutrophils, and neutrophil elastase degrades plasminogen, the target substrate of tPA, that is required to generate fibrinolysis. We hypothesized that pleural fluid from patients with pleural space infection would show high elastase activity, evidence of inflammatory plasminogen degradation, and low fibrinolytic potential in response to tPA that could be rescued with plasminogen supplementation. Does neutrophil elastase degradation of plasminogen contribute to intrapleural fibrinolytic failure? We obtained infected pleural fluid and circulating plasma from hospitalized adults (n = 10) with institutional review board approval from a randomized trial evaluating intrapleural fibrinolytics vs surgery for initial management of pleural space infection. Samples were collected before the intervention and on days 1, 2, and 3 after the intervention. Activity assays, enzyme-linked immunosorbent assays, and Western blot analysis were performed, and turbidimetric measurements of fibrinolysis were obtained from pleural fluid with and without exogenous plasminogen supplementation. Results are reported as median (interquartile range) or number (percentage) as appropriate, with an α value of .05. Pleural fluid elastase activity was more than fourfold higher ( = .02) and plasminogen antigen levels were more than threefold lower ( = .04) than their corresponding plasma values. Pleural fluid Western blot analysis demonstrated abundant plasminogen degradation fragments consistent with elastase degradation patterns. We found that plasminogen activator inhibitor 1 (PAI-1), the native tPA inhibitor, showed high antigen levels before the intervention, but the overwhelming majority of this PAI-1 (82%) was not active ( = .003), and all PAI-1 activity was lost by day 2 after the intervention in patients receiving intrapleural tPA and deoxyribonuclease. Finally, using turbidity clot lysis assays, we found that the pleural fluid of 9 of 10 patients was unable to generate a significant fibrinolytic response when challenged with tPA and that plasminogen supplementation rescued fibrinolysis in all patients. Our findings suggest that inflammatory plasminogen deficiency, not high PAI-1 activity, is a significant contributor to intrapleural fibrinolytic failure. ; No.: NCT03583931; URL:

中文翻译：

---

中性粒细胞介导的炎性纤溶酶原降解，而不是高纤溶酶原激活物抑制剂-1，可能是胸膜内纤维蛋白溶解失败和效率低下的原因


复杂的胸膜腔感染通常需要使用多剂量的胸膜内组织纤溶酶原激活剂 （tPA） 和脱氧核糖核酸酶进行治疗，治疗失败通常需要手术。胸膜感染富含中性粒细胞，中性粒细胞弹性蛋白酶降解纤溶酶原，纤溶酶原是 tPA 的靶底物，是产生纤维蛋白溶解所必需的。我们假设胸膜腔感染患者的胸腔积液会表现出高弹性蛋白酶活性、炎性纤溶酶原降解的证据以及响应 tPA 的低纤溶电位，这可以通过补充纤溶酶原来挽救。纤溶酶原的中性粒细胞弹性蛋白酶降解是否会导致胸膜内纤溶衰竭？我们从住院成人 （n = 10） 那里获得了感染的胸腔积液和循环血浆，并获得了机构审查委员会的批准，该随机试验评估了胸膜腔内纤溶药物与手术对胸膜腔感染初始管理的影响。在干预前和干预后第 1 天、第 2 天和第 3 天收集样本。进行活性测定、酶联免疫吸附测定和 Western blot 分析，从补充和不补充外源性纤溶酶原的胸腔液中获得纤维蛋白溶解的比浊测量。结果酌情以中位数（四分位距）或数字（百分比）报告，α值为 .05。胸腔积液弹性蛋白酶活性比其相应的血浆值高四倍以上 （ = .02），纤溶酶原抗原水平低三倍以上 （ = .04）。胸腔积液 Western 印迹分析显示丰富的纤溶酶原降解片段与弹性蛋白酶降解模式一致。 我们发现纤溶酶原激活物抑制剂 1 （PAI-1），天然 tPA 抑制剂，在干预前表现出高抗原水平，但该 PAI-1 中的绝大多数 （82%） 没有活性 （ = .003），并且在干预后第 2 天，所有 PAI-1 活性都丢失了接受胸膜内 tPA 和脱氧核糖核酸酶的患者。最后，使用浊度凝块溶解测定，我们发现 10 名患者中有 9 名的胸腔积液在接受 tPA 攻击时无法产生显着的纤维蛋白溶解反应，并且补充纤溶酶原挽救了所有患者的纤维蛋白溶解。我们的研究结果表明，炎性纤溶酶原缺乏症，而不是高 PAI-1 活性，是导致胸膜内纤溶失败的重要因素。;不。： NCT03583931;网址：