Role of serum soluble Fas/soluble Fas ligand and TNF-alpha on response to interferon-alpha therapy in chronic hepatitis C

Inflammatory and cardiovascular diseases biomarkers in chronic hepatitis C virus infection: A review

Hepatitis C virus (HCV) infects 180 million people worldwide and over 4 million people in the United States. HCV infection is a major cause of chronic liver disease and is recognized as a risk factor for clinical cardiovascular disease (CVD). Many studies have shown increased prevalence of cardiac and inflammatory biomarkers in patients with chronic HCV infection (CHC), and though these markers may be used to risk stratify people for cardiac disease in the general population their role in the HCV population is unknown. Patients with CHC have elevated cardiac and inflammatory biomarkers compared to noninfected controls which may play a role in CVD risk stratification. We undertook a systematic review of inflammatory and cardiac biomarkers in people with HCV infection with a focus on the effect of CHC on serum levels of these markers and their utility as predictors of CVD in this population. Medline, EMBASE, and Cochrane databases were searched for relevant articles until June 2019. A total of 2430 results were reviewed with 115 studies included. Our review revealed that HCV infection significantly alters serum levels of markers of inflammation, endothelial function, and cardiac dysfunction prior to HCV treatment, and some of which may change in response to HCV therapy. Current risk stratification tools for development of CVD in the general population may not account for the increased inflammatory markers that appear to be elevated among HCV‐infected patients contributing to increased CVD risk.

Differential Serum Cytokine Profiles in Patients with Chronic Hepatitis B, C, and Hepatocellular Carcinoma

Cytokines play an important role in the pathogenesis of cirrhosis and hepatocellular carcinoma (HCC), most cases of which are related to either hepatitis B virus (HBV) or hepatitis C virus (HCV). Prior studies have examined differences in individual cytokine levels in patients with chronic liver disease, but comprehensive cytokine profiling data across different clinical characteristics are lacking. We examined serum cytokine profiles of 411 patients with HCC (n = 102: 32% HBV, 54% HCV, 14% non-viral) and without HCC (n = 309: 39% HBV, 39% HCV, 22% non-viral). Multiplex analysis (Luminex 200 IS) was used to measure serum levels of 51 common cytokines. Random forest machine learning was used to obtain receiver operator characteristic curves and to determine individual cytokine importance using Z scores of mean fluorescence intensity for individual cytokines. Among HCC and non-HCC patients, cytokine profiles differed between HBV and HCV patients (area under curve (AUC) 0.82 for HCC, 0.90 for non-HCC). Cytokine profiles did not distinguish cirrhotic HBV patients with and without HCC (AUC 0.503) or HCV patients with and without HCC (AUC 0.63). In conclusion, patients with HBV or HCV infection, with or without HCC, have distinctly different cytokine profiles, suggesting potential differences in disease pathogenesis and/or disease characteristics.

Correlation between vitamin D levels and apoptosis in geriatric patients infected with hepatitis C virus genotype 4

Background

Vitamin D levels play a pivotal role in most biological processes and differ according to age. A deficiency of vitamin D in chronic hepatitis C (CHC) patients has been shown to be linked with the severity of liver fibrosis, but little is known about the mechanism of this association.

Objective

In this study, we evaluate the potential interrelation between vitamin D levels, oxidative stress, and apoptosis, based on liver fibrosis in geriatric patients infected with hepatitis C virus (HCV) genotype 4.

Subjects and methods

A total of 120 adult individuals aged 30–68 years were recruited in this study. Of these, 20 healthy subjects (15 men and five women) with a mean age of 48.3±6.1 years were selected as controls, and 100 patients with a mean age of 47.8±4.9 years with chronic HCV (CHC) who had undergone liver biopsy (80 men and 20 women) were included in this study. Based on liver radiographic (computed tomography, magnetic resonance imaging) and histological Metavir system analyses, the CHC patients were classified into three groups: asymptomatic CHC carriers (n=30), fibrosis (n=25), and cirrhosis (n=45). HCV RNA, HCV genotypes, inflammatory cytokines AFP and TNFα, 25-hydroxyvitamin D (25[OH]D) levels, apoptotic markers single-stranded DNA (ssDNA) and soluble Fas (sFas), and oxidative stress markers nitric oxide (NO) and total antioxidant capacity (TAC) were estimated by using molecular, immunoassay, and colorimetric techniques.

Results

Approximately 30% of the study population (n=30) were diagnosed as asymptomatic CHC carriers, and 70% of the study population (n=70) had severe fibrosis; these were classified into fibrosis and cirrhosis. There was a significant reduction in 25(OH)D levels and TAC activity, along with an increase in levels of NO, AFP, TNFα, ssDNA, and sFas in fibrosis and cirrhosis subjects compared with those of asymptomatic CHC carriers and health controls. The deficiency in 25(OH)D levels correlated positively with sFas, ssDNA, AFP, TNFα, NO, and TAC, and negatively with age, sex, liver function, body mass index, homeostatic model assessment – insulin resistance, HCV RNA, and viral load. Significant intercorrelation was reported between serum 25(OH)D concentrations and apoptotic and oxidative markers, which suggested progression of liver pathogenesis and fibrogenesis via oxidative and apoptotic mechanisms.

Conclusion

The data showed that vitamin D status was significantly correlated with pathogenesis and fibrogenesis of the liver in geriatric patients infected with HCV genotype 4. The deficiency in 25(OH)D levels was shown to have a pivotal role in the pathogenesis of liver via apoptotic, oxidative stress, and inflammatory mechanistic pathways. The data point to adequate vitamin D levels being recommended for a good response to treatment strategies, especially in older CHC patients.

Hepatic apoptotic markers are not predictors for the virological response to interferon-based therapy in chronic hepatitis C patients

INTRODUCTION

Chronic hepatitis C virus (HCV) infection is a major health problem worldwide. The majority of cases involving HCV infection develop into chronic hepatitis because of a failure to develop an effective immune response. Apoptosis of the hepatocytes plays a significant role in the pathogenesis of HCV infection: the interaction between the Fas antigen on hepatocytes and the Fas ligand on T cells corresponds to the main mechanism for hepatocyte damage. Interferon (IFN)-α has antiviral, immunoregulatory, and antiproliferative properties, and apoptosis seems to be a critical event in the action mechanisms of both IFNs. In this study, we aimed to detect any relationship between apoptotic markers in the liver and the response to the treatment.

MATERIALS AND METHODS

The study included 180 chronic HCV patients treated with IFN and ribavirin in four centers. Apoptotic markers (Fas, Fas ligand, Fas-associated death domain, caspases 3, 8, and 9, and in-situ apoptosis) were studied in the liver. The age, sex of the patients, response to therapy, ALT level, viral load, and genotype were recorded.

RESULTS

The results of the study showed that the histological activity index and fibrosis correlated with CD95 staining density, caspase-8 intensiveness, and portal and parenchymal Fas ligand scores. The apoptotic parameters of the responsive cases were not significantly different from those of the unresponsive cases.

CONCLUSION

The apoptotic parameters studied in liver tissue are associated with inflammation and fibrosis; however, these parameters may not predict response to treatment.

HCV NS3 protease enhances liver fibrosis via binding to and activating TGF-β type I receptor

Viruses sometimes mimic host proteins and hijack the host cell machinery. Hepatitis C virus (HCV) causes liver fibrosis, a process largely mediated by the overexpression of transforming growth factor (TGF)-β and collagen, although the precise underlying mechanism is unknown. Here, we report that HCV non-structural protein 3 (NS3) protease affects the antigenicity and bioactivity of TGF-β2 in (CAGA)₉-Luc CCL64 cells and in human hepatic cell lines via binding to TGF-β type I receptor (TβRI). Tumor necrosis factor (TNF)-α facilitates this mechanism by increasing the colocalization of TβRI with NS3 protease on the surface of HCV-infected cells. An anti-NS3 antibody against computationally predicted binding sites for TβRI blocked the TGF-β mimetic activities of NS3 in vitro and attenuated liver fibrosis in HCV-infected chimeric mice. These data suggest that HCV NS3 protease mimics TGF-β2 and functions, at least in part, via directly binding to and activating TβRI, thereby enhancing liver fibrosis.

Serum apoptosis markers related to liver damage in chronic hepatitis C: sFas as a marker of advanced fibrosis in children and adults while M30 of severe steatosis only in children

Background

Liver biopsy represents the gold standard for evaluating damage and progression in patients with chronic hepatitis C (CHC); however, developing noninvasive tests that can predict liver injury represents a growing medical need. Considering that hepatocyte apoptosis plays a role in CHC pathogenesis; the aim of our study was to evaluate the presence of different apoptosis markers that correlate with liver injury in a cohort of pediatric and adult patients with CHC.

Methods

Liver biopsies and concomitant serum samples from 22 pediatric and 22 adult patients with CHC were analyzed. Histological parameters were evaluated. In serum samples soluble Fas (sFas), caspase activity and caspase-generated neoepitope of the CK-18 proteolytic fragment (M30) were measured.

Results

sFas was associated with fibrosis severity in pediatric (significant fibrosis p = 0.03, advanced fibrosis p = 0.01) and adult patients (advanced fibrosis p = 0.02). M30 levels were elevated in pediatric patients with severe steatosis (p = 0.01) while in adults no relation with any histological variable was observed. Caspase activity levels were higher in pediatric samples with significant fibrosis (p = 0.03) and they were associated with hepatitis severity (p = 0.04) in adult patients. The diagnostic accuracy evaluation demonstrated only a good performance for sFas to evaluate advanced fibrosis both in children (AUROC: 0.812) and adults (AUROC: 0.800) as well as for M30 to determine steatosis severity in children (AUROC: 0.833).

Conclusions

Serum sFas could be considered a possible marker of advanced fibrosis both in pediatric and adult patient with CHC as well as M30 might be a good predictor of steatosis severity in children.

Modulation of DNA damage and alteration of gene expression during aflatoxicosis via dietary supplementation of Spirulina (Arthrospira) and Whey protein concentrate

Spirulina (SPN) and Whey protein (WPC) are being touted as functional foods with a number of health benefits. SPN is blue green algae while WPC is a protein complex derived from milk and both have strong antioxidant activity and provoke a free radical scavenging enzyme system. The aim of the present study was to evaluate the antioxidant potentials of SPN and WPC to regulate the alteration of genes' expression and counteract oxidative stress in rats during aflatoxecosis. Eighty male Sprague-Dawley rats were divided into eight groups, which included the control group, the group fed with aflatoxins (AFs)-contaminated diet (2.5 mg/kg diet) for 30 day, the group treated orally with WPC (300 mg/kg b.w.), the group treated orally with SPN (50 mg/kg b.w), the group treated orally with WPC plus SPN and the groups fed with AFs-contaminated diet and treated orally with WPC, SPN and/or WPC. Oxidative stress markers and gene expression were assayed in liver and testis and the damage of DNA was evaluated by DNA fragmentation and micronucleus tests. The results demonstrated that supplementation of SPN and/or WPC reduced the oxidative stress induced by AFs as indicated by decreased lipid peroxidation level, increased glutathione content and up-regulated PHGPx gene expression. Both agents succeed to inhibit DNA damage as indicated by the down-regulation of Fas gene expression, and decreased the percentage of DNA fragmentation and micronucleated erythrocytes. Moreover, WPC was found to be effective than SPN and the combined treatment was more effective than the single treatment. It could be concluded that both SPN and WPC induced a protective action and regulated the alteration of genes expression induced by AFs; however, the combined treatment may be useful than the single treatment.

Apelin serum level in Egyptian patients with chronic hepatitis C

OBJECTIVE

Highlighting the apelin system would present a new therapeutic target for liver disease. Apelin; endogenous ligand for the orphan receptor APJ, was recently suggested to be associated with fibrosis progression and cirrhosis in addition to insulin resistance (IR) and inflammation. The present study was conducted to evaluate blood apelin level changes among 73 chronic hepatitis C (CHC) Egyptian patients and if associated with body mass index (BMI), IR, and tumor necrosis factor-alpha (TNF-α). Serum apelin levels were significantly higher in patients with CHC with median value (3.25) when compared with controls (1.11), at P < 0.0001, with significant apelin variations among asymptomatic carriers (ASC), fibrosis, and cirrhosis patients, and also among obese and nonobese patients. Multiple regression analysis depicted that BMI, triglycerides, and total cholesterol were independent correlation factors to apelin levels, whereas TNF-α was found to be significantly negatively correlated to adjusted apelin in CHC patients (r = -0.5944, P < 0.0001). IR was positively correlated to adjusted apelin in CHC patients (r = 0.2663, P < 0.05).

CONCLUSION

Apelin level varies among stages of CHC, which may contribute to fibrosis progression. In addition, obesity and IR could act as comorbid factors affecting apelin level in patients with CHC.

Evidence of a significant role for Fas-mediated apoptosis in HCV clearance during pegylated interferon plus ribavirin combination therapy

BACKGROUND

The role of apoptosis in treatment-induced HCV clearance is controversial. We sought to assess the kinetics of serum apoptosis-related cytokines during pegylated interferon-α2a or -α2b plus weight-based ribavirin therapy for genotype 1 chronic HCV infection.

METHODS

Serum levels of soluble Fas (sFas), soluble Fas ligand (sFasL) and soluble tumour necrosis factor receptor I (sTNF-RI) were measured at baseline, week 12 and 24 weeks after the end of therapy.

RESULTS

Sustained virological response (SVR) was achieved in 46% of the 164 included patients, 29% had a non-response (NR) and 25% had relapse (RR). NR patients presented with higher levels of sFasL at baseline and lower levels of sTNF-RI at week 12 as compared to RR and SVR patients. Lower concentrations of sFas were observed in SVR patients 24 weeks after treatment as compared to RR and NR patients. An increase in sFas at week 12 followed by a significant drop 24 weeks after therapy was observed among SVR patients. An increase in sFasL during and after treatment was observed in RR and SVR patients. NR patients exhibited an earlier drop in sTNF-RI levels as compared to RR and SVR patients.

CONCLUSIONS

Virological response during HCV therapy was associated with an increase of sFas and sFasL, and maintenance of increased concentrations of sTNF-RI.

Hepatocyte growth factor protects against Fas-mediated liver apoptosis in transgenic mice

BACKGROUND

Apoptosis via the Fas/Fas ligand signalling system plays an important role in the development of various liver diseases. The administration of an agonistic anti-Fas antibody to mice causes massive hepatic apoptosis and fulminant hepatic failure. Several growth factors including hepatocyte growth factor (HGF) have been found to prevent apoptosis.

METHODS

In this study, we demonstrated the overexpression of HGF to have a protective effect on Fas-mediated hepatic apoptosis using a transgenic mice (Tg mice) model.

RESULTS

In HGF Tg mice, the elevation of alanine aminotransferase was dramatically inhibited at 12 and 24 h after the administration of 0.15 mg/kg anti-Fas antibody. HGF Tg mice showed a significantly lower number of apoptotic hepatocytes at 12 h compared with wild-type (WT) mice. Furthermore, 85% (six of seven) HGF Tg mice were able to survive after the administration of 0.3 mg/kg anti-Fas antibody, while none of the WT mice survived. The Bcl-xL expression was increased in HGF Tg mice, while there was no difference in the expression of Bax, Bid, Mcl-1 and bcl-2 between WT mice and HGF Tg mice. In addition, the HGF Tg mice showed more Akt phosphorylation than the WT mice both before and after the anti-Fas antibody injection.

CONCLUSIONS

Taken together, our findings suggest that HGF protects against Fas-mediated liver apoptosis in vivo, and the upregulation of Bcl-xL via Akt activation may also play a role in the protective effects of HGF.

Expression of pro- and anti-inflammatory cytokines in relation to apoptotic genes in Egyptian liver disease patients associated with HCV-genotype-4

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common tumors worldwide strongly linked to hepatitis C virus (HCV) infection. However, the exact pathogenetic mechanisms are still unclear.

METHODS

We assessed the expression of apoptosis genes (GSK3-B, AKT-1, Bcl-2), inflammatory cytokines (TNFalpha, TNF-RI, TNF-RII, IL-6, IL-6R), anti-inflammatory IL-10, CRP and alphaFP by reverse transcription-polymerase chain reaction (RT-PCR) in 33 HCC, 25 chronic hepatitis and 16 asymptomatic HCV carrier positive for HCV subjects. Also, pooled normal liver tissues and HepG2 cells were used as controls.

RESULTS

Hepatocellular carcinoma and liver disease (LD) showed reduced expression of GSK-3beta, TNFalpha, TNF-R I, TNF-RII, IL-10 and overexpression of IL-6R and CRP with no significant difference between the two groups. AFP was expressed in HCC only (33%). AKT, BCL2 and IL-6 showed normal, reduced and overexpression in studied patients with a significant difference between AFP, AKT overexpression (67% and 30%), BCL2 overexpression (49% and 10%) and reduced IL-6 in between HCC and LD. The morphologically normal tissues adjacent to tumors showed aberrant expression of AKT, IL-6, CRP, TNFalpha and TNFRI. A significant relation was observed between cirrhosis and GSK-3beta, AKT and IL-6 (P = 0.0018, P = 0.018, P = 0.0001; respectively).

CONCLUSIONS

Aberrant expressions of AKT, GSK3-B, and BCL2 are common events in HCV-associated LD and HCC. AKT, GSK3-B and IL-6 are significantly associated with cirrhosis and could be used as biomarkers for both early detection and molecular target therapy for the prevention of HCC development. TNFRII, GSK3-B and s-AFP could be used as prognostic factors that can predict the clinical outcome of HCC patients.

Hepatitis C virus infection and apoptosis

Apoptosis is central for the control and elimination of viral infections. In chronic hepatitis C virus (HCV) infection, enhanced hepatocyte apoptosis and upregulation of the death inducing ligands CD95/Fas, TRAIL and TNFα occur. Nevertheless, HCV infection persists in the majority of patients. The impact of apoptosis in chronic HCV infection is not well understood. It may be harmful by triggering liver fibrosis, or essential in interferon (IFN) induced HCV elimination. For virtually all HCV proteins, pro- and anti-apoptotic effects have been described, especially for the core and NS5A protein. To date, it is not known which HCV protein affects apoptosis in vivo and whether the infectious virions act pro- or anti-apoptotic. With the availability of an infectious tissue culture system, we now can address pathophysiologically relevant issues. This review focuses on the effect of HCV infection and different HCV proteins on apoptosis and of the corresponding signaling cascades.

Immunomodulators, sFas and Fas-L as potential noninvasive predictors of IFN treatment in patients with HCV genotype-4

Recent studies have indicated that cytokines can be used as markers for disease progression in hepatitis C virus (HCV)-infected patients, therefore this study was conducted to determine the influence of pegylated IFN vs standard IFN on interleukin-2 receptor (IL-2R), IL-6R, IL-8, TNFR-I, TNFR-II, sFas, and sFas-L in Egyptian patients with chronic hepatitis C genotype 4, as no previous studies have been performed on this genotype. We also aim at establishing a possible relationship between these cytokines and the response to INF to determine whether they can be used as noninvasive markers for the response to INF therapy and as monitors for the outcome of treatment. Thirty-eight patients with chronic HCV hepatitis were investigated for the serum levels of the previously mentioned cytokines in a randomized opened controlled trial (22 patients treated with pegylated IFN and 16 patients treated with standard IFN). Cytokine levels were measured by ELISA at 0, 1 and 12 months of IFN therapy. There was marked increase in the serum levels of IL-2R and IL-6R in nonresponders to pegylated interferon, IL-8, TNFR-I and II were significantly higher in nonresponders to standard interferon but were also high in responders of pegylated interferon. sFas and sFas-L showed high levels among responders to pegylated interferon but the standard interferon was again less effective in this regard. Serum levels of TNFR-II, sFas and sFas-L have the potential to be used as serological markers for response to pegylated IFN therapy, and IL-8 is a predictor for nonresponse. Moreover, TNFR-I and II have the potential to be used as markers of response to standard IFN treatment. The persistent correlation between sFas and TNFR-II may elaborate the possible role of pegylated IFN in the induction of apoptosis as a possible new mechanism of viral clearance during treatment with pegylated interferon treatment.

Hepatitis C virus: virology and experimental systems

Over the past several years, significant progress has been made toward the understanding of hepatitis C virus, especially the development of in vitro cell culture models. The scientific community now has the tools to gain a better understanding of the virus, which should translate into better clinical therapeutic modalities. Many new drugs are currently being evaluated, and a few are already undergoing clinica trials. This article focuses on the current advances in hepatitis C virus virology.

Cytokine profile in Egyptian hepatitis C virus genotype-4 in relation to liver disease progression

AIM: To observe the imbalance between T helper cell Th1 and Th2 cytokines in several chronic hepatitis disease at different stages of disease progression.

METHODS: We measured the cytokine levels of Th1 (IL-2 and IL-2R), Th2 (IL-10) and the pro-inflammatory cytokines (IL-6 and IL-6R and TNF and TNF-RI and II) by the ELISA technique in the sera of 33 hepatocellular carcinoma (HCC) patients and 20 chronic liver disease (CLD) patients. In addition, 20 asymptomatic hepatitis C virus carriers and 20 healthy subjects negative for hepatitis C virus(HCV) markers served as controls.

RESULTS: Anti-HCV antibodies were found to be positive in 94% of HCC cases and 75% of CLD cases. On the other hand, HCV viremia was detected using RT-PCR in 67% of HCC cases and 65% of CLD cases. HBsAg was positive in 9% of HCC cases and 30% of CLD cases. Also bilharzial-Ab was positive in 55% of HCC cases, 65% of CLD cases and in 70% of asymptomatic carriers (ASC). HCC patients had significantly higher values of IL-2R, TNF-RII (P<0.001), and TNF-RI (P>0.05), but lower TNFα (P<0.001) and IL-6 (P = 0.032) in comparison to ASC. But, in comparison to non-cancer controls, HCC patients had higher values of IL-2R, IL-6R, TNF-RI and TNF-RII, but lower TNF-α (P<0.001). CLD patients had higher IL-2R, TNF-RI, and TNF-RII (P<0.001) than ASC. But, in comparison to non-cancer controls, CLD patients had higher values of IL-2R, TNF-RI and TNF-RII, but lower TNF-α (P<0.001). IL-10 was higher (though not significantly) in HCC and CLD patients than in symptomatic carriers and non-cancer controls.

CONCLUSION: Liver disease progression from CLD to HCC due to HCV genotype-4 infection is associated with an imbalance between Th1 and Th2 cytokines. IL-2R, TNF-RI, and TNF-RII could be used as potential markers.

Biomedicines to reduce inflammation but not viral load in chronic HCV--what's the sense?

Although cytokines and cytotoxic T lymphocytes (CTL) are among the predominant mechanisms of host defense against viral pathogens, they can induce an inflammatory response that often leads to tissue injury. Hepatitis C virus (HCV) infection, a major cause of liver-related disease, results in the induction of proinflammatory cytokines, such as tumor necrosis factor-alpha (TNF-alpha), and CTL activity, followed by liver injury. Although inflammation facilitates the wound healing process, chronic persistence over several decades results in scar accumulation, fibrosis and often cirrhosis. This review summarizes biological data implicating a cause-and-effect relationship between TNF-alpha levels and the progression of fibrosis in chronic HCV infections, in contrast to the role of TNF-alpha in hepatitis B virus infections. Furthermore, an overview of therapeutic approaches to halting the inflammatory cascade in individuals with chronic HCV, including the use of agents to reduce the level of TNF-alpha, is presented.

Variations in the serum concentrations of soluble Fas and soluble Fas ligand in Vietnamese patients infected with hepatitis B virus

Earlier studies of both chronic hepatitis B and C virus (HBV and HCV) patients have shown a strong correlation between the soluble membrane Fas (sFas) and Fas protein expression on hepatocytes. The serum concentrations of sFas and soluble Fas ligand (sFasL) was examined in both healthy and HBV-infected Vietnamese patients to determine their relationship with the outcome of HBV infection. Patients with chronic rather than acute HBV had significantly higher amounts of sFas and sFasL, whilst the highest concentrations of both molecules were detected in those with malignant forms of HBV infection. sFas and sFasL concentrations tended to increase with a profile that paralleled the progression from asymptomatic to acute through chronic to malignant states, most markedly in the case of sFas. The sFas:sFasL ratio highlighted the relative predominance of sFas in those with acute and chronic HBV compared with asymptomatic or severe forms. In patients with hepatocellular carcinoma (HCC) a significant correlation was also observed between sFasL and alpha-feto protein (AFP) levels. The results indicate that sFas and to a lesser extent sFasL levels are to some degree associated with clinical progression in HBV infection.

Elevated serum soluble Fas levels in the various stages of hepatitis C virus-induced liver disease

We aimed to determine serum soluble Fas antigen (sFas) levels at various stages of hepatitis C virus (HCV)-induced liver disease, and investigate correlations between serum sFas levels and clinical, biochemical and pathologic features. Sixty-five patients were categorized into five groups: 1, chronic active hepatitis C, elevated alanine aminotransferase (ALT), HCV-polymerase chain reaction (PCR) positive; 2, responders to interferon + ribavirin therapy; 3, cirrhosis; 4, chronic hepatitis C, normal ALT, HVC-PCR positive; and 5, sustained responders. Group 6 comprised 15 control individuals. Serum sFas levels were measured by enzyme-linked immunosorbent assay. Significant differences in serum sFas levels were found between the following groups: 1 and 2; 1 and 3; 1 and 4; 1 and 6; and 3 and 6. Serum sFas levels did not correlate with ALT, histological activity or HCV-PCR positivity within group 1. Serum sFas levels appear to increase in advanced stages of HCV-induced liver disease, as a result of host-related immunological factors.

To interfere and to anti-interfere: the interplay between hepatitis C virus and interferon

As popular strategies used by numerous viruses, interception of interferon (IFN) signaling and inhibition of IFN-induced antiviral functions allow viruses to evade the host immune response and set up successful infections. Hepatitis C virus (HCV), the leading cause of chronic liver disease worldwide and a major public health hazard, causes persistent infection in the majority of infected individuals. IFN-based therapies, currently the only ones available for HCV infection, have been unable to eliminate viral infection in the majority of patients, and many studies suggest that HCV possesses mechanisms to antagonize the IFN-induced antiviral response. Multiple viral, host, and IFN-associated factors have been implicated in the interplay between HCV and IFN. Two viral proteins, NS5A and E2, became the focus of much attention and extensive study because of their abilities to inhibit IFN-induced, double-stranded RNA-activated protein kinase (PKR), a major mediator of the IFN-induced biologic response, and to perturb the IFN signaling pathway. In this review, we discuss the significance of the interferon sensitivity determining region (ISDR) within NS5A, which has been the subject of intense debates. In addition, we discuss the potential mechanisms by which NS5A interferes with IFN signaling and the current working models. Further understanding of the molecular mechanisms underlying the interaction between HCV and IFN will likely facilitate improvement of current IFN-based therapies and development of novel treatments for the HCV pandemic. Future HCV research will benefit from both the development of efficient, convenient model systems for viral propagation, and the utilization of high throughput, genomic-scale approaches.

Transforming growth factor alpha protects against Fas-mediated liver apoptosis in mice

The Fas/Fas ligand interaction plays a crucial role in various liver diseases, and administration of agonistic anti-Fas antibody to mice causes massive hepatic apoptosis and fulminant hepatic failure. Several growth factors have recently been found to function in preventing apoptosis. In this study, we demonstrated that overexpression of transforming growth factor alpha (TGFalpha) has a dramatic protective effect on Fas-mediated hepatic apoptosis at the biochemical and histological levels. Moreover, 85.7% (six out of seven) of TGFalpha transgenic mice survived the lethal liver damage, whereas all wild-type mice died. Expression of Bcl-xL, an anti-apoptotic protein, was greatly increased in the transgenic mice. Taken together, our findings suggest that TGFalpha protects against Fas-mediated liver apoptosis in vivo and up-regulation of Bcl-xL may participate in protective effect of TGFalpha.

Apoptosis mediated by the Fas system in the fulminant hepatitis by hepatitis B virus

The pathogenesis of the fulminant hepatitis B is poorly understood and both viral factors and the hosts immune response play a role. Previous studies in liver tissues of patients with chronic hepatitis B showed overexpression of Fas antigen and this was correlated with the activity of the hepatitis. The present study was done to determine the role of Fas in fulminant hepatitis B and the virological characteristics of hepatitis B infection. We studied three patients with fulminant hepatitis B. HBV-DNA was detected by dot-blot hybridization and polymerase chain reaction. The S and C gene were sequenced. Levels of serum soluble Fas antigen were detected by enzymoimmunoassays procedure. Apoptosis was determined by the TUNEL technique. Fas antigen expression was evaluated by a immunoperoxidase method. Ten healthy subjects acted as controls. The three patients showed a high expression of Fas antigen particularly among infiltrating lymphocytes; in these areas we also found many cells with in situ DNA nick labelling signals in the nuclei of most viable hepatocytes. Serum levels of soluble Fas antigen were higher in patients with fulminant hepatitis B than in controls. No specific genome mutations of hepatitis B virus were found. These data suggest that the Fas system involved in the liver injury of patients with fulminant hepatitis B.