转化生长因子β与肝纤维化的研究

肝纤维化是慢性肝病的共同病理基础,可进一步发展为肝硬化、肝衰竭和门脉高压,其本质为肝星状细胞（HSC）的活化和细胞外基质（ECM）的过度沉积。目前认为肝纤维化的形成是由于多种损肝因子,启动炎性细胞,导致HSC激活,活化的HSC事实上是ECM的重要组成成分,     

肝纤维化的靶向治疗

肝纤维化是各种致病因子造成肝细胞损伤,激活库普弗细胞并使之分泌多种细胞因子,随同血小板、炎性细胞等分泌的多种细胞因子共同作用于HSC,使之转化为肌成纤维细胞；细胞因子同时激活纤维母细胞,合成并分泌大量的ECM沉积在肝Disse间隙内,抑制肝细胞生长因子及胶原酶的合成和分泌,导致肝纤维化形成,Ⅰ、Ⅲ型胶原是ECM的主要成分。[第一段]     

肝纤维化进程中细胞外基质对肝星状细胞的作用及机制研究进展*

肝纤维化是一种肝内弥漫性细胞外基质（ECM）过度沉积的病理过程,且肝星状细胞（HSC）的激活是肝纤维化发生发展的中心环节。本文主要介绍了在肝纤维化进程中ECM各种成分比例、分子结构的改变及其ECM分子空间结构改变对HSC的激活、增殖和凋亡的作用和机制。     

bFGF在肝纤维化中的研究进展

肝纤维化是慢性肝病共有的病理改变,肝星状细胞(HSC)激活分泌大量的细胞外基质(ECM)沉积在肝内引起肝纤维化.碱性成纤维细胞生长因子(bFGF)是从牛脑垂体中分离纯化而来,能促进多种细胞产生ECM,导致肝纤维化形成.     

抗肝纤维化治疗研究进展

肝纤维化是各种慢性肝病发展至肝硬化的必经阶段,是由于各种致病因子（常见病因为病毒性肝炎、慢性酒精中毒、遗传和代谢疾病、化学毒物或药物、肝脏淤血、寄生虫、脂肪肝等）引起肝脏损伤和炎症,导致细胞外基质（ECM）在肝脏过度沉积。其中肝星状细胞（HSC）的活化是纤维化的中心事件。随着肝纤维化发生机制进一步阐明,防治策略也进行了相应调整,抑制HSC活化和抑制ECM合成,促进降解,成为当今抗肝纤维化的关键措施。     

肝星状细胞的移行机制及药物干预研究

肝纤维化是各种慢性肝病向肝硬化发展的必经阶段。其关键环节是肝星状细胞（hepatic stellate cell,HSC）的激活。HSC的活化是导致细胞外基质（extracellular matrix,ECM）过度沉积,最终形成肝纤维化的主要原因。经典干预手段通过抑制HSC活化和促进HSC凋亡来逆转肝纤维化的进程,但也有部分学者认为HSC移行也是肝纤维化形成的重要机制之一。     

肝细胞凋亡在肝纤维化中的作用

肝纤维化系肝组织内细胞外基质(ECM)过度增生与异常沉积,导致肝脏结构和/或功能异常改变的病理变化。过去20年,对肝纤维化的病理机制研究取得了长足进步,如明确了肝纤维化的细胞学基础在于肝星状细胞(HSC)活化,生化学基础在于ECM代谢紊乱,尤其是近年来基本明确了转化生长因子β(TGF-β)等促纤维化细胞因子刺激HSC活化。但是治疗学进展缓慢,治疗策略主要针对HSC活化与ECM代谢降解等,而这些方法尚未取得理想的临床疗效。肝细胞约占肝脏细胞总量的80%,数量最多,功能重要。肝细胞损伤尤其是肝细胞凋亡、细胞支架结构完整性在肝纤维化中…     

β-榄香烯对肝星状细胞周期及凋亡的影响

肝纤维化是肝脏细胞外基质（EcM）异常生成和积累的结果，肝星状细胞（hepatic stellate cells，HSC）为肝纤维化形成的关键细胞。HSC在诸多因素（如细胞因子、生长因子、肝细胞、Kupffer细胞、内皮细胞等）的调控下，HSC持续激活导致胶原生成细胞增多，并最终引起ECM的大量沉积，同时在肝纤维化的逆转过程中，HSC的减少主要通过凋亡机制。因此HSC的激活增殖是各种原因引起肝纤维化形成的中心环节，阻抑激活的HSC增殖和诱导其凋亡是治疗慢性肝损伤和肝纤维化的重要策略。莪术为临床抗肝纤维化治疗的常用中药，不少研究显示该药具有抗肝纤维化、抑制ECM生成的作用。榄香烯为其有效成分，具有抗血栓形成、抑制肿瘤细胞增殖、诱导肿瘤细胞凋亡的作用。榄香烯是否为莪术抗肝纤维化的有效成分尚少见报道，本实验采用传代的HSC系HSC-T6初步探讨β-榄香烯对HSC凋亡、增殖的影响。     

肝星状细胞激活的研究进展

肝纤维化(HF)是各种慢性肝病共有的病理改变,其特点是以胶原为主的细胞外基质(ECM)在肝内过度沉积。肝星状细胞(HSC)激活、增殖、迁移、合成和分泌大量ECM是HF形成和发展的中心环节与细胞学基础。在此过程中,许多细胞因子(CK)、氧化应激产物、ECM组构的广泛改变、化学分子、细胞周期调控因子以及核转录因子(NF)参与HSC的激活。     

肝星状细胞与肝纤维化

肝纤维化是各种慢性肝病损伤修复过程的共同结果,由于肝内纤维生成和降解失衡,导致过多的胶原在肝内沉积,常伴有炎症、缺血缺氧,最终可发展为肝硬化。目前认为,细胞外基质（ECM）过多产生和沉积是肝纤维化的核心表现,活化的肝星状细胞（HSC）仍是细胞外基质的主要细胞来源。因此,肝星状细胞的活化是肝纤维化发生的中心环节。     

诱导活化肝星状细胞凋亡主要信号通路的研究进展

肝纤维化是各种病因引起的肝脏慢性进行性的病理过程,肝纤维化时细胞外基质(ECM)合成大于降解导致ECM在肝内大量沉积。肝星状细胞(HSC)的激活、转化并产生分泌大量ECM是肝纤维化形成的关键环节。而通过诱导活化的HSC发生凋亡是逆转肝纤维化的重要手段之一。就主要的凋亡信号通路:死亡受体通路、线粒体通路、内质网通路、神经生长因子通路进行一一阐述。指出了对活化HSC的凋亡途径进行选择性的药物干预有望发挥抗肝纤维化的作用。     

Hepatic fibrogenesis]

In acute injury, liver recovers completely without any scarring change or complication. However, large portion of liver is changed into fibrotic state by excessive production of extracellular matrix (ECM) under chronic injury. Excessive production of ECM results in hepatic fibrosis and repeated process of hepatic fibrosis progress into liver cirrhosis. Liver cirrhosis is an irreversible and terminal state of chronic liver disease and one of the major causes of death in Korea. To block the progression to liver cirrhosis, various studies in the field of virology and immunology have been proceeded. Recently, studies on the hepatic fibrogenesis have progressed with the development of molecular biology. Hepatic stellate cells (HSC) play a key role in the pathogenesis of hepatic fibrosis by producing ECM. The degree of hepatic fibrosis depends on the proliferation and activation of HSC and increased net production of collagen. Therefore, inhibition of HSC activation is one of the main ways to block the progression of hepatic fibrosis. Many kinds of factors such as oxidative stress, acetaldehyde, ascorbic acid, transforming growth factor-beta (TGF-beta) and carbon tetrachloride (CCl4) have been reported to activate HSC and stimulate collagen gene expression. Although there are no definite and effective antifibrogenic agents, possible candidates are antioxidants, interferon, retinoids such as beta-carotene, flavonoids, renin-angiotensin system inhibitors and peroxisome proliferator activated receptor-gamma (PPAR-gamma) agonists. We tried to evaluate the charateristics of HSC in order to develop agents that inhibit hepatic fibrogenesis.     

Hepatic stellate cells: a target for the treatment of liver fibrosis

Hepatic fibrosis is a wound-healing process that occurs when the liver is injured chronically. Hepatic stellate cells (HSC) are responsible for the excess production of extracellular matrix (ECM) components. The activation of HSC, a key issue in the pathogenesis of hepatic fibrosis, is mediated by various cytokines and reactive oxygen species released from the damaged hepatocytes and activated Kupffer cells. Therefore, inhibition of HSC activation and its related subsequent events, such as increased production of ECM components and enhanced proliferation, are crucial goals for intervention in the hepatic fibrogenesis cascade. This is especially true when the etiology is unknown or there is no established therapy for the cause of the chronic injury. This review explores the rationale for choosing HSC as a target for the pharmacological, molecular, and other novel therapeutics for hepatic fibrosis. One focus of this review is the inhibition of two cytokines, transforming growth factor-β and platelet-derived growth factor, which are important in hepatic fibrogenesis. A number of new agents, such as Chinese herbal recipes and herbal extracts, silymarin, S-adenosyl-l-methionine, polyenylphosphatidylcholine, and pentoxifylline are also discussed. Received: April 3, 2000 / Accepted: April 28, 2000     

肌细胞增强因子2A与肝星状细胞活化关系的体内实验研究

背景：转录调控在肝星状细胞（HSC）活化过程中起重要作用,研究显示转录因子肌细胞增强因子2（MEF2）参与了HSC的活化过程。目的：探讨肝纤维化形成过程中MEF2家族成员MEF2A与HSC活化的关系。方法：实验开始时处死6只大鼠作为0周对照组,64只大鼠随机分为正常对照组和肝纤维化模型组。模型组大鼠皮下注射60％CCL（0．3ml／100g,每周2次）复制肝纤维化模型;正常对照组大鼠与模型组于相同条件下饲养,不予任何处理。造模开始后3、6、9、12周分批处死大鼠,取肝组织,实时荧光定量聚合酶链反应（PCR）检测MEF2AmRNA表达．蛋白质印迹法检测MEF2A蛋白和HSC活化标记物α-平滑肌肌动蛋白（α-SMA）表达,VanGieson染色定量分析肝内胶原含量。结果：正常肝组织中仅有少量MEF2AmRNA和蛋白表达;随着肝纤维化的形成,肝组织MEF2AmRNA和蛋白表达量逐渐增加（P〈0．05）,MEF2A与Q—SMA蛋白表达呈正相关（r=0．88,P〈0．05）。肝内胶原含量随肝纤维化的形成呈递增趋势（P〈0．01）。结论：MEF2A参与了CCl4。诱导的大鼠肝纤维化形成过程中HSC的活化和增殖。     

转化生长因子-β信号通路与肝纤维化分子治疗研究进展

肝星状细胞（HSC）是肝纤维化发生的关键细胞，转化生长因子-β（TGF-β）在肝纤维化发生、发展过程中具有活化HSC、促进细胞外基质（ECM）合成和沉积等作用。TGF-β-Smad信号通路是TGF-β发挥生物学效应的主要通路，其分子组成和分子调节复杂，与其他信号通路存在广泛交互影响。深入研究TGF-β-Smad信号通路可进一步阐述肝纤维化的发病机制，为肝纤维化的防治提供新的有效途径。     

肝细胞生长因子与肝纤维化的研究进展

肝细胞生长因子是一种具有多种生物活性的细胞因子,其在促进肝细胞增殖、抑制肝星状细胞活化等方面有重要作用.肝纤维化进展过程中,各种因素引起肝细胞持续损伤,使损伤部位肝细胞再生,肝星状细胞激活,细胞外基质大量沉积,从而导致肝纤维化形成.此文就肝细胞生长因子的生物学特性及其在肝纤维化中发挥的作用作一综述.     

A role for cytokines as regulators of hepatic fibrogenesis

It is evident that hepatic fibrogenesis is a complex process involving a cascade of cytokines which interact to enhance the expression of ECM. Cytokines involved early in this cascade may serve as proinflammatory agents or as stimulators of macrophage and Ito cell activation and proliferation, while those cytokines involved later in this process may be directly fibrogenic. Furthermore, we speculate that a balance between profibrogenic and antifibrogenic cytokines normally exists but in the presence of hepatic insults, a relative superabundance of the fibrogenic factors promotes the development of liver fibrosis. To date, most of the evidence supporting a role for cytokines in liver fibrosis has been obtained inin vitro systems or in animal models. We now need to extend these findings to man in order to determine whether a similar cascade of cytokines is important in the development of this pathologic process in man. Further delineation of these cytokines (as well as other profibrogenic soluble factors), and the mechanisms by which they act, are critical to our development of more rational forms of therapy for liver fibrosis.     

干扰素治疗肝纤维化机制的研究进展

肝纤维化是多种病因导致慢性肝病共有的病理改变,肝纤维化为一动态过程,属可逆性病变,但若进一步发展至肝硬化阶段,则不可逆,因此阻断抑制或逆转肝纤维化是治疗慢性肝病的一个十分重要的目标.干扰素(interferon,IFN)具有广泛的抗病毒、抗肿瘤和免疫调节作用.目前有许多研究认为干扰素(IFN)具有抗肝纤维化作用,并已在临床应用中取得一定效果,但其抗肝纤维化的确切机制尚不明了,有学者认为可能与其抗病毒,抑制肝星状细胞的活化增殖,促进肝星状细胞的凋亡,抑制细胞外基质(ECM)合成,促进细胞外基质降解等作用有关.     

Bezafibrate prevents hepatic stellate cell activation and fibrogenesis in a murine steatohepatitis model,and suppresses fibrogenic response induced by transforming growth factor‐β1 in a cultured stellate cell line

Aim: The aim of this study was to investigate the preventive actions of bezafibrate against non‐alcoholic steatohepatitis (NASH), the activation of hepatic stellate cells (HSC), and fibrogenesis by using a model of NASH and an in vitro model. Methods: Male KK‐A^y/TaJcl (KK‐A^y) mice were fed a methionine and choline‐deficient (MCD) diet or a MCD diet containing bezafibrate or pioglitazone for 7 weeks, after which biochemical parameters, pathological changes, and hepatic mRNA levels were assessed. An in vitro HSC model was designed by using a previously described RI‐T cell line stimulated by transforming growth factor‐β1 (TGF‐β1). Results: MCD diet‐fed KK‐A^y mice developed hepatic steatosis, oxidative stress, inflammation, and hepatic fibrosis. Bezafibrate markedly decreased the hepatic content of triglyceride accumulation of fatty droplets within hepatocytes, and increased the expression of hepatic fatty acid β‐oxidative genes in MCD diet‐fed KK‐A^y mice. Bezafibrate markedly inhibited the increases in the plasma alanine aminotransferase level and hepatic content of thiobarbituric acid‐reactive substances in this model. Moreover, it dramatically reduced hepatic inflammatory changes and fibrosis concomitantly with marked reductions in the mRNA levels for inflammatory cytokine, chemokine, and profibrogenic genes. Importantly, both bezafibrate and pioglitazone markedly reduced the mRNA levels of profibrogenic and fibrogenic genes in TGF‐β1‐stimulated cells. Conclusion: Bezafibrate improved hepatic steatosis and potently prevented inflammation, oxidative stress, HSC activation, and fibrogenesis in the liver. Moreover, this study was the first to demonstrate that bezafibrate directly inhibits hepatic fibrogenic response induced by TGF‐β1 in vitro. Hence bezafibrate may be a new therapeutic strategy against NASH and hepatic fibrosis.