Abstract：
In decompensated cirrhosis, the severity of portal hypertension (PHT) is associated with increased hepatic endothelial nitric oxide synthase (eNOS) trafficking inducer (Nostrin), but the mechanism remains unclear. AIM: To investigate: (1) Whether in cirrhosis-PHT models, ± superimposed inflammation to mimic acute-on-chronic liver failure (ACLF) modulates hepatic nitric oxide synthase trafficking inducer (NOSTRIN) expression, nitric oxide (NO) synthesis, and/or endothelial dysfunction (ED); and (2) Whether the \"angiotensin II type 1 receptor blocker\" candesartan cilexetil (CC) affects this pathway. CD-1 mice received intraperitoneal carbon tetrachloride injections (CCl4 15% v/v in corn oil, 0.5 mL/kg) twice weekly for 12 wk to induce cirrhosis. After 12 wk, mice were randomized to receive 2-wk oral administration of CC (8 mg/kg) ± LPS. At sacrifice, plasma (biochemical indicators, cytokines, and angiotensin II) and liver tissues (histopathology, Sirius-red stains, and molecular studies) were analysed. Moreover, Nostrin gene knockdown was tested in human umbilical vein endothelial cells (HUVECs). When compared to naïve animals, CCl4-treated animals showed markedly elevated hepatic Nostrin expression (P < 0.0001), while hepatic peNOS expression (measure of eNOS activity) was significantly reduced (P < 0.05). LPS challenge further increased Nostrin and reduced peNOS expression (P < 0.05 for both) in cirrhotic animals. Portal pressure and subsequent hepatic vascular resistance were also increased in all cirrhotic animals following LPS challenge. In CCl4 ± LPS-treated animals, CC treatment significantly reduced Nostrin (P < 0.05) and increased hepatic cGMP (P < 0.01). NOSIP, caveolin-1, NFκB, and iNOS protein expression were significantly increased in CCl4-treated animals (P < 0.05 for all). CC treatment non-significantly lowered NOSIP and caveolin-1 expression while iNOS and NFκB expression was significantly reduced in CCl4 + LPS-treated animals (P < 0.05 for both). Furthermore, Nostrin knockdown significantly improved peNOS expression and associated NO synthesis and reduced inflammation in HUVECs. This study is the first to indicate a potential mechanistic role for the Nostrin-eNOS-NO pathway in cirrhosis and ACLF development. Moreover, this pathway provides a potential therapeutic target given the ameliorative response to Candesartan treatment.
摘要：
在失代偿期肝硬化中，门静脉高压症（PHT）的严重程度与肝内皮一氧化氮合酶（eNOS）运输诱导剂（Nostrin）增加有关，但机制尚不清楚。目的:探讨:(1)在肝硬化-PHT模型中,模拟慢性急性肝衰竭（ACLF）的±叠加炎症调节肝一氧化氮合酶运输诱导剂（NOSTRIN）表达，一氧化氮(NO)合成,和/或内皮功能障碍（ED）；（2）“血管紧张素II1型受体阻滞剂”坎地沙坦西酯（CC）是否影响该途径。CD-1小鼠接受腹膜内四氯化碳注射（CCl4在玉米油中15％v/v，0.5mL/kg），每周两次，持续12周，以诱导肝硬化。12周后,小鼠随机接受2周口服CC(8mg/kg)±LPS。在牺牲时，血浆(生化指标，细胞因子,和血管紧张素II）和肝脏组织（组织病理学，天狼星红色污渍，和分子研究)进行了分析。此外，在人脐静脉内皮细胞（HUVEC）中测试了Nostrin基因敲低。与天真的动物相比，CCl4处理的动物显示出肝Nostrin表达显着升高（P<0.0001），而肝脏peNOS表达（eNOS活性的测量）显着降低（P<0.05）。LPS攻击在肝硬化动物中进一步增加Nostrin和减少peNOS表达(两者P<0.05)。LPS攻击后，所有肝硬化动物的门静脉压力和随后的肝血管阻力也增加。在CCl4±LPS处理的动物中，CC治疗显着降低了Nostrin（P<0.05），增加了肝脏cGMP（P<0.01）。NOSIP,caveolin-1,NFkB,在CCl4处理的动物中,iNOS蛋白表达显著增加(均P<0.05)。在CCl4+LPS处理的动物中,CC处理不显著降低NOSIP和小窝蛋白-1表达,而iNOS和NFkB表达显著降低(两者P<0.05)。此外，Nostrin敲低显著改善了HUVECs中的peNOS表达和相关的NO合成并减少了炎症。这项研究首次表明了Nostrin-eNOS-NO途径在肝硬化和ACLF发展中的潜在机制作用。此外，考虑到坎地沙坦治疗的改善反应,该途径提供了一个潜在的治疗靶点.
