Advances and challenges in studying hepatitis C virus in its native environment
Center for the Study of Hepatitis C, The Rockefeller University, 1230 York Avenue, Box 64, New York, NY 10065, USA. Expert review of gastroenterology & hepatology
(Impact Factor: 2.42).
10/2010; 4(5):541-50. DOI: 10.1586/egh.10.53
Approximately 2% of the worldwide population is infected with hepatitis C virus (HCV), the major causative agent of non-A, non-B hepatitis. Although substantial progress has been made in developing tools to dissect the viral life cycle, most in vitro studies rely on hepatoma cell lines, which are functionally disparate from the natural in vivo target of the virus – hepatocytes. To gain insights into virus–host interactions, there is a need for HCV-model systems that more closely mimic the physiological environment of the liver. Here, we discuss recent advances in culture and detection systems that facilitate the study of HCV in primary cells. Use of these new models may help bridge the gap between in vitro studies and clinical research.
Available from: Koen Vercauteren
- "Consequently, studies on virus–host interactions have been hampered by limited in vivo and ex vivo models that more closely mimic the natural infection and environment of the liver. Primary HCV isolates show no, or only poor ability to replicate in tissue culture and the use of primary hepatocytes in culture is complicated by rapid loss of differentiation , low-level viral replication and poor reproducibility  . Some advances have been made in this area by the use of primary human hepatocytes in combination with a highly replicative JFH1-variant , fluorescence-based reporter systems in co-cultures of primary human hepatocytes with supportive stroma , primary human foetal liver cultures  , a human liver slice model  and more recently with induced pluripotent stem cell derived hepatocyte-like cells   . "
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ABSTRACT: The development and evaluation of effective therapies and vaccines for the hepatitis C virus (HCV) and the study of its interactions with the mammalian host have been hindered for a long time by the absence of suitable small animal models. Due to the narrow host tropism of HCV, the development of mice that can be robustly engrafted with human hepatocytes was a major breakthrough since they recapitulate the complete HCV life cycle. This model has been useful to investigate many aspects of the HCV life cycle, including antiviral interventions. However, studies of cellular immunity, immunopathogenesis and resulting liver diseases have been hampered by the lack of a small animal model with a functional immune system. In this review, we summarize the evolution of in vivo models for the study of HCV.
Available from: Rafael Aldabe
- "Experiments involving human hepatocytes are essential for the development of new drugs and for unraveling fundamental biological mechanisms underlying metabolic and viral diseases . In vitro cultures of primary cells are not suitable for metabolic or virological studies as human hepatocytes rapidly dedifferentiate losing the mature metabolic phenotype and the ability to support replication of hepatotropic viruses such as HCV and HBV [2,3]. Several studies have documented that transplanted human hepatocytes can integrate into the murine liver parenchyma and that this chimeric organ may serve as a valuable tool for biological, virological and pharmacological studies requiring the use of human hepatic cells [4-6]. "
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ABSTRACT: It has been shown that the liver of immunodeficient mice can be efficiently repopulated with human hepatocytes when subjected to chronic hepatocellular damage. Mice with such chimeric livers represent useful reagents for medical and clinical studies. However all previously reported models of humanized livers are difficult to implement as they involve cross-breeding of immunodeficient mice with mice exhibiting genetic alterations causing sustained hepatic injury. In this paper we attempted to create chimeric livers by inducing persistent hepatocellular damage in immunodeficient Rag2(-/-) γc(-/-) mice using an adenovirus encoding herpes virus thymidine kinase (AdTk) and two consecutive doses of ganciclovir (GCV). We found that this treatment resulted in hepatocellular damage persisting for at least 10 weeks and enabled efficient engraftment and proliferation within the liver of either human or allogenic hepatocytes. Interestingly, while the nodules generated from the transplanted mouse hepatocytes were well vascularized, the human hepatocytes experienced progressive depolarization and exhibited reduced numbers of murine endothelial cells inside the nodules. In conclusion, AdTk/GCV-induced liver damage licenses the liver of immunodeficient mice for allogenic and xenogenic hepatocyte repopulation. This approach represents a simple alternative strategy for chimeric liver generation using immunodeficient mice without additional genetic manipulation of the germ line.
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ABSTRACT: Hepatocellular carcinoma cell lines supporting HCV replication in culture produce infectious particles (cell culture-derived HCV) for only a limited number of strains. Mutations in the viral genome resulting from the combined effects of the error-prone HCV RNA polymerase coupled with selection of the best-adapted viral variants generate a drift in cell culture-derived HCV properties, which can result in a total loss of in vivo infectivity in the chimpanzee model. Other systems for producing HCV or HCV-related particles, some of which bypass HCV RNA replication, have been developed to study the biology of this virus, with limitations of their own. This review briefly analyzes the pros and cons of these in vitro models, focusing on recent advances.
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