Department of Hepatobiliary Pancreatic and Transplant SurgeryMie University Graduate School of MedicineTsu cityMieJapan.
Liver Transpl. 2021 Feb;27(3):363-384. doi: 10.1002/lt.25929. Epub 2020 Dec 9.
Thrombin is a key player in the coagulation cascade, and it is attracting much attention as a promotor of cellular injured signaling. In ischemia/reperfusion injury (IRI), which is a severe complication of liver transplantation, thrombin may also promote tissue damage. The aim of this study is to reveal whether dabigatran, a direct thrombin inhibitor, can attenuate hepatic IRI with focusing on a protection of sinusoidal endothelial cells (SECs). Both clinical patients who underwent hepatectomy and in vivo mice model of 60-minute hepatic partial-warm IRII, thrombin generation was evaluated before and after IRI. In next study, IRI mice were treated with or without dabigatran. In addition, hepatic SECs and hepatocytes pretreated with or without dabigatran were incubated in hypoxia/reoxygenation (H-R) environment in vitro. Thrombin generation evaluated by thrombin-antithrombin complex (TAT) was significantly enhanced after IRI in the clinical study and in vivo study. Thrombin exacerbated lactate dehydrogenase cytotoxicity levels in a dose-dependent manner in vitro. In an IRI model of mice, dabigatran treatment significantly improved liver histological damage, induced sinusoidal protection, and provided both antiapoptotic and anti-inflammatory effects. Furthermore, dabigatran not only enhanced endogenous thrombomodulin (TM) but also reduced excessive serum high-mobility group box-1 (HMGB-1). In H-R models of SECs, not hepatocytes, pretreatment with dabigatran markedly attenuated H-R damage, enhanced TM expression in cell lysate, and decreased extracellular HMGB-1. The supernatant of SECs pretreated with dabigatran protected hepatocytes from H-R damage and cellular death. Thrombin exacerbated hepatic IRI, and excessive extracellular HMGB-1 caused severe inflammation-induced and apoptosis-induced liver damage. In this situation, dabigatran treatment improved vascular integrity via sinusoidal protection and degraded HMGB-1 by endogenous TM enhancement on SECs, greatly ameliorating hepatic IRI.
凝血酶是凝血级联反应中的关键因子，作为细胞损伤信号的促进剂，它受到了广泛关注。在肝移植的严重并发症缺血/再灌注损伤（IRI）中，凝血酶也可能促进组织损伤。本研究旨在揭示直接凝血酶抑制剂达比加群是否可以通过保护肝窦内皮细胞（SECs）来减轻肝 IRI。我们评估了临床行肝切除术的患者和体内 60 分钟肝脏部分热缺血再灌注损伤模型中，IRI 前后的凝血酶生成情况。接下来，IRI 小鼠用或不用达比加群处理，此外，体外用或不用达比加群预处理肝 SECs 和肝细胞，然后在缺氧/复氧（H-R）环境中孵育。临床研究和体内研究均显示，IRI 后凝血酶-抗凝血酶复合物（TAT）的凝血酶生成显著增加。凝血酶在体外以剂量依赖性方式加剧乳酸脱氢酶细胞毒性水平。在小鼠 IRI 模型中，达比加群治疗可显著改善肝组织损伤，诱导窦保护，并提供抗凋亡和抗炎作用。此外，达比加群不仅增强了内源性血栓调节蛋白（TM），还降低了过量的血清高迁移率族蛋白 B1（HMGB-1）。在 SECs 的 H-R 模型中，而非肝细胞，达比加群预处理可显著减轻 H-R 损伤，增加细胞裂解物中的 TM 表达，并减少细胞外 HMGB-1。用达比加群预处理的 SECs 上清液可保护肝细胞免受 H-R 损伤和细胞死亡。凝血酶加重肝 IRI，过量的细胞外 HMGB-1 导致严重的炎症诱导和凋亡诱导的肝损伤。在这种情况下，达比加群通过窦保护改善血管完整性，并通过内源性 TM 增强降解 HMGB-1，大大改善肝 IRI。
