阿尔维林治疗门脉高压症的作用及机制研究

Portal hypertension is a very frequent and serious complication of chronic liver disease, which indicates a poor prognosis of patients with hepatic cirrhosis. Alverine is a synthetic derivative of papaverine and a selective smooth muscle relaxant used for functional gastrointestinal disorders. It was reported that alverine had a derect combination with the nuclear receptor transcription factor hepatic nuclear factor 4 alpha (HNF4α) and acted as HNF4α activator. Our previous study has showed that a decreased expression of HNF4α was found in the liver with fibrosis, and overexpression of HNF4α attenuated hepatic fibrosis in rats. In the preliminary experiment, we have found that alverine decreased the portal pressure of Thioacetamide (TAA) induced cirrhotic portal hypertensive rats, and had an equivalent efficacy to carvedilol in the treatment of portal hypertension in rats. These data indicate that alverine have a therapeutic effect on the portal hypertension. We also found that alverine inhibited the contraction of isolated portal vein in vitro, suggesting that portal vein could be one of the targets of alverine. In this study, we will further confirm this therapeutic effect using multiple animal models of cirrhotic portal hypertension. Moreover, we will clarify the role of HNF4α in the treatment of portal hypertension with alverine. Finally, the pathophysiological mechanisms of alverine on the lowering portal pressure will be further illustrated using in vitro and in vivo experiments. This study will provide a novel therapeutic strategy of portal hypertension and shed new light on the pathophysiological mechanism of portal hypertension development.

门脉高压症是慢性肝病进展至肝硬化后常见的并发症之一，严重影响肝硬化患者预后。阿尔维林为人工合成的罂粟碱衍生物，是一种选择性平滑肌松弛药，尚无文献报道其在肝纤维化、肝硬化门脉高压症中的作用。有研究指出，阿尔维林可以与HNF4α直接结合，是HNF4α的激活剂。我们既往研究表明，肝脏纤维化过程中HNF4α表达下调，上调HNF4α表达可抑制肝脏纤维化。前期工作中，我们发现阿尔维林可以治疗TAA诱导的大鼠肝硬化门脉高压症，其降压效果与卡维地洛相当。体外血管环实验发现阿尔维林可以明显抑制离体门静脉收缩，提示门脉血管可能是阿尔维林作用的靶器官之一。本课题将在前期研究基础上，进一步明确阿尔维林对多种肝硬化门脉高压症模型大鼠的治疗作用；探究HNF4α在阿尔维林治疗中的作用；寻找并阐明阿尔维林治疗肝硬化门脉高压症的作用机制，以揭示门脉高压症发生发展的病理生理机制，为临床治疗门脉高压症提供新的治疗策略和。

门脉高压症是慢性肝病进展至肝硬化后常见的并发症之一，其基本的病理生理特征是门静脉系统血流受阻和（或）血流量增加，可导致腹水形成、脾功能亢进、食管胃底静脉曲张破裂出血、肝性脑病、肝肾综合征等，严重影响肝硬化预后，但针对门脉高压的基础发病机制缺乏相应的治疗策略。阿尔维林为人工合成的罂粟碱衍生物，是一种选择性平滑肌松弛药。我们发现阿尔维林可以治疗CCl4、TAA、BDL诱导的肝硬化以及PPVL制备的非肝硬化大鼠门脉高压症，其降门脉压效果与临床治疗门脉高压一线药物卡维地洛相当；与卡维地洛可引起低血压、心动过缓等副作用不同，阿尔维林治疗门脉高压的同时对全身血流动力学无明显作用。此外，我们发现阿尔维林对肝纤维化无明显作用，其发挥降门脉压力作用主要通过抑制门静脉本身收缩。进一步研究发现，阿尔维林为五羟色胺受体1A（HTR1A）选择性拮抗剂。HTR1A在门脉高压症动物模型及患者门静脉组织中表达上调，选择性HTR1A激动剂可升高正常大鼠门静脉压力、加剧肝硬化大鼠门脉高压，选择性HTR1A拮抗剂或敲除Htr1a基因可显著肝硬化或非肝硬化大鼠门脉高压。机制研究表明，调控HTR1A活性可通过门静脉平滑肌细胞cAMP信号通路调控其收缩进而调节门脉压力。我们的研究表明门静脉HTR1A在门脉高压病理生理中的关键作用，利用阿尔维林或选择性HTR1A拮抗剂可能是门脉高压治疗的新策略。.在本课题研究中，我们还利用TAA和DDC制备小鼠肝纤维化模型，发现舒洛地特（伟素）可显著改善小鼠肝纤维化。进一步研究表明，舒洛地特治疗降低了纤维化小鼠肝脏中的纤维化相关基因和肝窦内皮细胞（LSECs）毛细血管化相关基因表达，并发现舒洛地特抑制了肝纤维化过程中LSECs的内皮-间充质转化过程。总之，我们的研究表明舒洛地特通过恢复分化的LSECs来减弱小鼠的肝纤维化，提示舒洛地特治疗可能是肝纤维化患者的一种潜在治疗方法。