In vitro Culture of Hepatitis C Virus (HCV) Using Immortalized Hepatocyte / 대한소화기학회지

BACKGROUND/AIMS: It is essential to develop an in vitro culture model of primary hepatocytes for the study of hepatocellular function and the pathogenesis of hepatitis C virus (HCV) infection. In this study, we have established the immortalized primary human hepatocyte (IPHH) and performed in vitro culture of HCV derived from human patient. METHODS: Primary human hepatocytes were isolated from surgically resected liver tissue and then were immortalized by transfection with the SV40 large T antigen. The characterization of the IPHH during culture was analyzed by immunocytochemistry, RT-PCR, Western blot, ELISA, and soft agar assay. Next, sera and/or liver tissue homogenates from surgically resected liver tissues of patients with HCV infection were inoculated for the culture of HCV in IPHH. After HCV RNA extraction from IPHH and culture media, positive or negative stranded HCV RNA was examined by specific nest RT-PCR. RESULTS: IPHH expressed liver-associated proteins but did not express alpha-fetoprotein. Also IPHH showed ammonia removal activity. With regard to its malignant potential, colony formation in soft agar assay was not observed. Next, positive and negative stranded HCV RNAs in IPHH infected with patient's sera plus liver tissue homogenates were clearly detected whereas those in IPHH infected with only patient's sera were not detected. CONCLUSIONS: These results demonstrated the phenotypic characteristics of IPHH and the feasibility in vitro culture system of HCV infected human samples. This system might be useful for study of pathogenesis of HCV infection or hepatocyte-based applications.

HCV core protein promotes liver fibrogenesis via up-regulation of CTGF with TGF-beta1

Liver cirrhosis is one of the major complications of hepatitis C virus (HCV) infection, but the mechanisms underlying HCV-related fibrogenesis are still not clear. Although the roles of HCV core protein remain poorly understood, it is supposed to play an important role in the regulation of cellular growth and hepatocarcinogenesis. The aim of this study was to examine the role of HCV core protein on the hepatic fibrogenesis. We established an in vitro co-culture system with primary hepatic stellate cell (HSC) isolated from rats, and a stable HepG2-HCV core cell line which had been transfected with HCV core gene. The expressions of fibrosis-related molecules transforming growth factor beta1 (TGF-beta1), transforming growth factor b receptor II (TGF beta RII), alpha-smooth muscle actin (alpha-SMA) and connective tissue growth factor (CTGF) were analyzed via histological or molecular methods. In addition, the expression levels of matrix metaloprotinase-2 (MMP-2) and collagen type I (Col I) from the co-cultured media were measured by zymogram and ELISA, respectively. The expressions of alpha-SMA, TGF-beta1, Col I, TGF beta RII and MMP-2 were significantly increased in the co-culture of stable HepG2-HCV core with HSC. Moreover, the significant increases of CTGF and TGF-beta1 in the HCV core-expressing cells were observed by either Northern or Western blot analysis. These results suggest that HCV core protein may contribute to the hepatic fibrogenesis via up-regulation of CTGF and TGF-beta1.

Prediction of Hepatic Fibrosis Using Serum Hyaluronic Acid in Patients with Chronic Liver Disease / 대한소화기학회지

BACKGROUND/AIMS: The extent of hepatic fibrosis is important in chronic liver disease. Liver biopsy is essential for diagnosis of fibrosis. However, biopsy is invasive and may not represent the whole liver state. Serum hyaluronic acid (HA), a major component of connective tissues, was introduced as a useful non-invasive index of hepatic fibrosis. The aim of this study was to evaluate the relationship among HA, the degree of fibrosis, several hematologic and biochemical parameters in patients with chronic liver diseases or post state liver transplantation (PSLT). METHODS: Total 102 cases were divided into 4 groups: 57 chronic hepatitis (CH), 12 cirrhosis, 21 hepatocellular carcinoma (HCC), 12 PSLT. HA was measured by enzyme-linked binding protein assay and evaluated in relation the degree of fibrosis, several hematologic and biochemical parameters. RESULTS: Among four groups, HCC showed the highest HA and HA of HCC significantly higher than that of CH. The degree of fibrosis were correlated with HA. HA was correlated with age, platelet count and albumin but, not with ALT and PT. There is no significant relation between HA and the presence of acute rejection in liver transplantation. CONCLUSIONS: In chronic liver diseases, HA is a useful non-invasive index of hepatic fibrosis and disease severity.

The Role of Hepatitis C Virus Core Protein on Liver Fibrogenesis: A Study Using an In Vitro Co-culture System / 대한소화기학회지

BACKGROUND/AIMS: The study of liver fibrogenesis by hepatitis C virus (HCV) has been limited due to the lack of an efficiency in vitro culture systems. In the present study, we investigated whether or not HCV core protein is directly related to liver fibrogenesis through stimulation of hepatic stellate cells (HSC). METHODS: Human and rat HSC were isolated and we established an in vitro co-culture system of a stable HepG2-HCV core cell line which was transfected with HCV core gene and primary HSC. We performed immunocytochemical staining and Western and Northern blot analysis in the stimulated HSC by HCV ocre protein to identify the expression of transforming growth factor beta1 (TGF-beta1), transforming growth factor beta receptor II (TGFbeta R II), alpha-smooth muscle actin (alpha-SMA) and connective tissue growth factor (CTGF). The expression of matrix metaloprotinase-2 (MMP-2) and collagen type I (Col I) in the culture media were measured by zymogram and ELISA, respectively. RESULTS: The expression of TGF-beta1 and CTGF was significantly higher in the stable HepG2-HCV core cell line than in HepG2 cells. Furthermore, the makers related to fibrosis such as alpha-SMA, TGF-beta1, Col I, TGFRII and MMP-2 were highly experssed in the co-culture of stable HepG2-HCV core with HSC. CONCLUSIONS: HCV core protein may play a direct role in the fibrogenesis of chronic liver disease with HCV infection.