Chronic subdural hematoma (CSDH) development involves inflammatory, angiogenetic, and fibrinolytic mechanisms, several components of which are now unraveled through intensive research. The urokinase plasminogen activator receptor (uPAR) is part of the plasminogen activator system and possesses inflammatory, angiogenetic, and fibrinolytic capabilities. As a first, this study aims to identify uPAR in the hematoma fluid, hematoma membrane, dura mater, and systemic blood from patients with CSDH and, if present, to investigate if the uPAR level at the time of surgery may be a predictor for later developing recurrent CSDH. uPAR expression in the hematoma membrane and dura mater was analyzed using immunohistochemistry and presented as the H-score of the positive immunostaining. The uPAR levels in the hematoma fluid and systemic blood were determined using a multiplex antibody bead kit (Luminex). Samples were collected at the time of the first CSDH surgery, and in the case of recurrent CSDH within 90 days, the samples were again collected at reoperation. A comparison of uPAR expression between the hematoma membrane and dura mater, as well as uPAR levels in systemic blood and hematoma fluid, was performed using the Wilcoxon rank sum test. We included 112 patients, 26 of whom had recurrent CSDH. The median hematoma uPAR level was 22,125 (14,845–33,237) and significantly higher than the median systemic blood level of 789 pg/L (465–2,088) (p < 0.001). Similarly, the uPAR level of the hematoma membrane was 14.3 (7.54–44.8) and significantly higher than the dural uPAR level of 0.81 (0.3–1.98) (p < 0.001). For the first time, we identified uPAR in the subdural fluid, hematoma membrane, dura mater, and systemic blood from patients with CSDH. The high expression of uPAR in the subdural fluid and hematoma membrane indicates that the mechanisms of CSDH are predominantly in the subdural fluid collection and surrounding hematoma membrane.

慢性硬膜下血肿 (CSDH) 的发展涉及炎症、血管生成和纤溶机制，其中的几个组成部分现已通过深入研究得以阐明。尿激酶纤溶酶原激活剂受体 (uPAR) 是纤溶酶原激活剂系统的一部分，具有炎症、血管生成和纤溶功能。首先，本研究旨在鉴定 CSDH 患者血肿液、血肿膜、硬脑膜和全身血液中的 uPAR，如果存在，则研究手术时的 uPAR 水平是否可以作为术后的预测因子。发展为复发性 CSDH。使用免疫组织化学分析血肿膜和硬脑膜中的 uPAR 表达，并以阳性免疫染色的 H 分数表示。使用多重抗体珠试剂盒（Luminex）测定血肿液和全身血液中的uPAR水平。在第一次CSDH手术时采集样本，如果90天内复发CSDH，则在再次手术时再次采集样本。使用 Wilcoxon 秩和检验比较血肿膜和硬脑膜之间的 uPAR 表达以及全身血液和血肿液中的 uPAR 水平。我们纳入了 112 名患者，其中 26 名患有复发性 CSDH。血肿 uPAR 中位水平为 22,125 (14,845–33,237)，显着高于全身血液中位水平 789 pg/L (465–2,088) ( p  < 0.001)。同样，血肿膜的 uPAR 水平为 14.3 (7.54–44.8)，显着高于硬脑膜 uPAR 水平 0.81 (0.3–1.98) ( p  < 0.001)。我们首次在 CSDH 患者的硬膜下液、血肿膜、硬脑膜和全身血液中鉴定出 uPAR。uPAR在硬膜下液和血肿膜中的高表达表明CSDH的机制主要在于硬膜下液聚集和周围血肿膜。