Review
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World J Hepatol. Apr 27, 2014; 6(4): 207-216
Published online Apr 27, 2014. doi: 10.4254/wjh.v6.i4.207
Mechanisms of fibrogenesis in liver cirrhosis: The molecular aspects of epithelial-mesenchymal transition
Sun-Jae Lee, Kyung-Hyun Kim, Kwan-Kyu Park
Sun-Jae Lee, Kyung-Hyun Kim, Kwan-Kyu Park, Department of Pathology, Catholic University of Daegu, College of Medicine, Daegu, 705-718, South Korea
Author contributions: Lee SJ and Park KK designed research; Lee SJ and Kim KH analyzed data; Lee SJ and Park KK wrote the paper; Lee SJ and Park KK contributed equally to this work.
Supported by The National Research Foundation of Korea Grant funded by the Korean Government, No. 2012R1A1A401015639
Correspondence to: Kwan-Kyu Park, MD, PhD, Department of Pathology, Catholic University of Daegu, College of Medicine, 3056-6 Daemyung 4-Dong, Nam-Gu, Daegu, 705-718, South Korea. kkpark@cu.ac.kr
Telephone: +82-53-6504149 Fax: +82-53-6504834
Received: October 28, 2013
Revised: January 9, 2014
Accepted: March 3, 2014
Published online: April 27, 2014
Processing time: 204 Days and 4.4 Hours
Abstract

Liver injuries are repaired by fibrosis and regeneration. The cause of fibrosis and diminished regeneration, especially in liver cirrhosis, is still unknown. Epithelial-mesenchymal transition (EMT) has been found to be associated with liver fibrosis. The possibility that EMT could contribute to hepatic fibrogenesis reinforced the concept that activated hepatic stellate cells are not the only key players in the hepatic fibrogenic process and that other cell types, either hepatic or bone marrow-derived cells could contribute to this process. Following an initial enthusiasm for the discovery of this novel pathway in fibrogenesis, more recent research has started to cast serious doubts upon the real relevance of this phenomenon in human fibrogenetic disorders. The debate on the authenticity of EMT or on its contribution to the fibrogenic process has become very animated. The overall result is a general confusion on the meaning and on the definition of several key aspects. The aim of this article is to describe how EMT participates to hepatic fibrosis and discuss the evidence of supporting this possibility in order to reach reasonable and useful conclusions.

Keywords: Epithelial-mesenchymal transition; Liver; Fibrosis; Transforming growth factor-beta1; Biological markers

Core tip: The cause of fibrosis and diminished regeneration, especially in liver cirrhosis, is still unknown. Epithelial-mesenchymal transition (EMT) has been found to be associated with liver fibrosis. The possibility that EMT could contribute to hepatic fibrogenesis reinforced the concept that activated hepatic stellate cells are not the only key players in the hepatic fibrogenic process. The aim of this article is to describe how EMT participates to hepatic fibrosis and discuss the evidence of supporting this possibility in order to reach reasonable and useful conclusions.