ALCOHOL-INDUCED LIVER FIBROSIS--AN IN VITRO MODEL

乙醇引起的肝硬化是世界范围内的主要死亡原因。 的 乙醇（ETOH）诱导肝纤维化的确切机制尚不清楚 但已经提出了几个假设：a）产品来自 ETOH代谢或受损细胞激活枯否细胞产生 诱导储脂细胞（FSC）增殖和过量的细胞因子 胶原蛋白生产。B）炎症细胞被驱动至肝脏， 趋化因子产生诱导纤维形成的细胞因子。c）产品 来源于ETOH代谢或受损细胞的纤维化和直接 诱导胶原基因表达。 各种机制可能会发生 然而，与此同时，它们对纤维形成的相对贡献是 未知 缺乏合适的模型来研究酒精性肝硬化， 阻碍了对ETOH诱导肝脏的基本机制的理解 纤维化 狒狒和大鼠模型是昂贵的，无法用于常规 问题研究 我们开发了一个共培养系统，其中包含两个 参与酒精性纤维化的重要细胞、肝细胞和FSC。 当前者将ETOH转化为乙醛（ACAL）时， 通过增加I型胶原基因的转录而转化为ACAL。 因此，我们认为， 该肝纤维化模型可用于探索 ETOH和其他肝毒素诱导肝细胞损伤和肝脏 纤维化 该模型简单，重现性好，可在 不存在或存在炎性成分。 我们的具体目标是 确定：a）肝细胞和FSC对胶原蛋白的相对贡献 和，B）在ETOH或ACAL施用后测定 分子水平，ETOH和/或ACAL诱导 I型胶原mRNA的表达。 我们将确定是否影响 通过TGF-β或其他细胞因子的产生来介导。 我们将 确定I型胶原启动子中的特定序列是否 ETOH或ACAL给药后胶原基因表达所需的， 我们将尝试研究特定的核蛋白是否 I型胶原基因的转录激活所需的。 我们 长期目标是了解肝脏诱导的机制 纤维化，并开发具有抗纤维化活性的药物， 预防或逆转纤维化。

Ethanol-induced liver cirrhosis is a major cause of death worldwide. The exact mechanism by which ethanol (ETOH) induces liver fibrosis is unknown but several hypothesis have been proposed: a) Products derived from either ETOH metabolism or injured cells activate Kupffer cells to produce cytokines that induce fat-storing cell (FSC) proliferation and excess collagen production. b) Inflammatory cells driven to the liver by chemoattactants produce cytokines that induce fibrogenesis. c) Products derived from ETOH metabolism or injured cells are fibrogenic and directly induce collagen gene expression. The various mechanisms may occur simultaneously,l however, their relative contribution to fibrogenesis is unknown. Lack of appropriate models to study alcohol-induced liver cirrhosis has hampered understanding of basic mechanisms by which ETOH induces liver fibrosis. Baboon and rat models are costly and unavailable for routine studies. We developed a co-culture, system that contains two of the important cells involved in alcoholic fibrosis, hepatocytes and FSCs. While the former transform ETOH to acetaldehyde (ACAL), the latter respond to ACAL by increasing transcription of type I collagen gene. Therefore, this model of liver fibrosis could be useful in exploring the mechanisms by which ETOH and other hepatotoxins induce hepatocyte damage and liver fibrosis. The model is simple, reproducible and can be analyzed in the absence or presence of inflammatory components. Our specific aims are to determine: a) the relative contribution of hepatocytes and FSC to collagen production after ETOH or ACAL administration and, b) to determine at the molecular level, possible mechanisms by which ETOH and/or ACAL induce the expression of type I collagen mRNA. We shall determine whether the effects are mediated 'via' the production of TGF-beta or other cytokines. We shall establish whether specific sequences in the promoter of type I collagen are required for collagen gene expression after ETOH or ACAL administration, and we shall attempt to study whether specific nuclear proteins are required for transcriptional activation of type I collagen gene. Our long-term goals are to understand the mechanisms of induction of liver fibrosis, and to develop drugs with antifibrogenic activity capable of preventing or reverting fibrosis.