The natural history of hepatitis C virus (HCV) infection

Epidemiology of hepatitis virus B and C

Hepatitis B and C virus infections constitute a significant health problem in Latin America. Approximately 400,000 new cases of hepatitis B per year and 10 million people infected with hepatitis C are estimated to occur. HBV and HCV genotype distribution may reflect the different patterns of migration to the Americas: Genotype F and H of HBV correspond to the Amerindian genotype. Overall, Genotype 1 is the most prevalent HCV genotype in the Caribbean and in South and Central America. Hepatitis B and C epidemiology needs to be considered in the context of dissimilar social and economic aspects among the countries of the region. Behaviors, cultural and ethical aspects, as well as environmental and organizational processes affect directly the way these diseases are approached in their diagnosis, treatment and prevention.

In vitro infection of immortalized primary hepatocytes by HCV genotype 4a and inhibition of virus replication by cyclosporin

Hepatitis C virus (HCV) is a major cause of liver cirrhosis and hepatocellular carcinoma worldwide. We previously reported that cyclosporin A (CsA) inhibits HCV-1b replication. However, its inhibition of JFH-1 (HCV-2a) was much less. Since HCV genotype clearly affects the in vitro and in vivo response to anti-viral therapy, we wished to examine the effect of CsA and its non-immunosuppressive derivative NIM811 on HCV genotype 4a replication. We first established an in vitro system supporting HCV-4a infection and replication using immortalized human hepatocytes, HuS-E7/DN24 (HuS) cells, and these cells were infected with sera obtained from Egyptian patients with chronic HCV-4a infection. HuS cells supported more robust HCV-4a replication than both HuH-7.5 and PH5CH8 cells, and HCV-4a infection and replication were completely inhibited by 3 mug/ml CsA and 0.5 mug/ml NIM811. Thus, HuS cells are a good model system supporting the infection and high-level replication of HCV-4a, and both CsA and NIM811 effectively inhibit HCV-4a replication in this system.

From the bench to the clinic and back again: translational biomarker discovery using in silico mining of pharmacogenomic data

To improve drug efficacy and safety and advance medical intervention in diseases, new biomarkers are urgently needed. Pharmacogenomics can provide a tool to discover and begin to qualify biomarkers useful for these indications and is readily applicable to multiple species. One can begin and end with genes or focus on tissue-derived expression analysis of those genes that encode secreted proteins to discover potential biomarkers that can be monitored in body fluids. The paper will discuss issues surrounding such investigations, show examples of translational biomarkers and end with a summary of the US FDA’s work in this field over the last 6 years.

Ultracentrifugation of serum samples allows detection of hepatitis C virus RNA in patients with occult hepatitis C

Occult hepatitis C virus (HCV) infection of patients with abnormal liver function tests of unknown origin who are anti-HCV and serum HCV RNA negative but who have HCV RNA in the liver has been described. As HCV replicates in the liver cells of these patients, it could be that the amount of circulating viral particles is under the detection limit of the most sensitive techniques. To prove this hypothesis, serum samples from 106 patients with occult HCV infection were analyzed. Two milliliters of serum was ultracentrifuged over a 10% sucrose cushion for 17 h at 100,000 x g(av), where av means average, and HCV RNA detection was performed by strand-specific real-time PCR. Out of the 106 patients, 62 (58.5%) had detectable serum HCV RNA levels after ultracentrifugation, with a median load of 70.5 copies/ml (range, 18 to 192). Iodixanol density gradient studies revealed that HCV RNA was positive at densities of 1.03 to 1.04 and from 1.08 to 1.19 g/ml, which were very similar to those found in the sera of patients with classical chronic HCV infection. Antigenomic HCV RNA was found in the livers of 56 of 62 (90.3%) patients with detectable serum HCV RNA levels after ultracentrifugation, compared to 27 of 44 (61.4%) negative patients (P < 0.001). No differences in the median loads of antigenomic HCV RNA between patients with an those without serum HCV RNA (4.5 x 10(4) [range, 7.9 x 10(2) to 1.0 x 10(6)] versus 2.3 x 10(4) [range, 4.0 x 10(2) to 2.2 x 10(5)]) were found. Alanine aminotransferase and gamma-glutamyl transpeptidase levels, liver necroinflammatory activity, and fibrosis did not differ between both groups. In conclusion, HCV RNA can be detected in the sera of patients with occult HCV infection after circulating viral particles are concentrated by ultracentrifugation.

Alcohol and the liver

PURPOSE OF REVIEW

This review aims to acquaint the reader with advances in 2006 in the epidemiology, genetics, detection, pathogenesis and treatment of alcoholic liver disease.

RECENT FINDINGS

Important discoveries have been made in pathogenesis and mechanism of disease, with great emphasis on the many pathways leading to oxidative stress, and the novel mechanism of endoplasmic reticulum stress that is proving to be important in the pathogenesis of many liver diseases. The reliability of ethyl glucuronide and other biomarkers for the detection of alcohol abuse is being better established. There have been no treatment advances for alcoholic liver disease but, on balance, steroids are still favored for carefully selected patients with alcoholic hepatitis. Many compounds tested in rodents may now be available for consideration for clinical trials. Criteria for patient selection and refusal for liver transplantation are being established but the 6 months abstinence rule still holds.

SUMMARY

Insights are being made into the pathogenesis of alcoholic liver disease but safe and effective therapies for both alcoholic hepatitis and alcoholic cirrhosis have yet to be discovered.

Mapping of the interacting domains of hepatitis C virus core protein and the double-stranded RNA-activated protein kinase PKR

Hepatitis C virus (HCV) core protein has been shown to exhibit several biological properties which suggest an important role in liver pathogenesis and carcinogenesis. During a previous study, we showed that core mutants, isolated from tumour, could directly interact with PKR and maintain it in an activated form. In the present report, we have further investigated this interaction and mapped the core and PKR domains involved. Using glutathion S-transferase fusion protein harbouring the different domains of core or PKR, we determined that the N-terminal 1-58 amino acid (aa) of core protein and the N-terminal 1-180 aa of PKR are responsible for this direct interaction. Using this system we also confirmed that the core-PKR interaction induced PKR autophosphorylation. Furthermore, we found that core protein co-localized and co-immunoprecipitated with PKR in cells expressing a full-length HCV replicon, thus confirming that this interaction occurs when all HCV proteins are expressed. Considering that the activation of PKR has been observed in some cancer cell lines and tissues, it suggests that, depending on the cellular context, PKR may stimulate or inhibit cell proliferation. The precise mapping of core-PKR interaction provides new data to study the molecular mechanism underlying HCV pathogenesis.

Targets of emerging therapies for viral hepatitis B and C

Viral hepatitis B and C, structurally two completely different viruses, commonly infect human hepatocytes and cause similar clinical manifestations. Since their discovery, IFN has been a pillar in the treatment. However, because of the different natures of the viruses, therapeutic approaches diverge and new treatment targets are tailored specifically for each virus. Herein, the authors analyse therapeutic approaches for hepatitis B virus (HBV) and hepatitis C virus (HCV) and focus on emerging concepts that are under clinical evaluation. In particular, promising viral inhibitors for HBV and HCV are reviewed and the current status of research for gene therapy for HCV is described. Immune therapy is a fast-moving field with fascinating results which include therapeutic vaccines and toll-like receptor agonists that could improve tomorrow's treatment approaches.

Alcohol and hepatitis C mortality among males and females in the United States: a life table analysis

OBJECTIVE

Evidence from previous studies suggests that heavy alcohol use (HAU) exacerbates the rate of fibrosis progression in the liver and results in increased probability for premature death among patients with hepatitis C virus (HCV) infection. The current study uses population-based mortality data to investigate whether heavy drinking affects the age of death among individuals with HCV and, if so, whether this effect differs between men and women.

METHODS

A total of 7,263,163 death records in the United States between 2000 and 2002 were drawn from the Multiple Cause of Death (MCD) public-use data files compiled by the National Center for Health Statistics (NCHS). International Classification of Diseases, Tenth Revision (ICD-10) codes were used to identify the presence of HCV (B17.1 and B18.2) and HAU (as indicated by alcohol-induced medical conditions, F10 and K70) either as the underlying cause or as one of the contributing causes of death. The deaths were divided into 4 distinctive cause-of-death categories: HCV without HAU, HAU without HCV, HCV plus HAU, and all others. The mean ages of death and the cumulative probabilities of death derived from multiple-cause life table were compared across these categories.

RESULTS

Hepatitis C virus deaths showed an excessive prevalence of HAU when compared with non-HCV deaths. Compared with deaths of HCV without HAU, the mean age of death was shortened for deaths of HCV plus HAU (from 55.1 to 50.0 years among males, and from 61.0 to 49.1 years among females). The cumulative probability of death before age 65 was much higher for the latter than the former group (0.91 vs 0.68 among males, and 0.88 vs 0.47 among females). While HCV alone showed a disproportionate effect on premature death in males, HAU presented a stronger effect in females, resulting in a "catching-up" effect that diminished the gender difference in age of HCV death.

CONCLUSIONS

This study provides mortality-based evidence to further establish heavy alcohol consumption as one of the key risk factors contributing to premature deaths from HCV in the United States. More importantly, this study, for the first time, presents empirical evidence that alcohol consumption affects men and women differently in HCV mortality.

Improving access to HCV treatment: external jugular venepuncture can overcome problems with difficult venous access

Many patients requiring antiviral treatment of chronic hepatitis C (HCV) have a background of significant injection drug use (IDU). In a proportion of patients, IDU results in difficulty with blood collection from conventional sites. We audited patients from the Liver Clinics and Drug Health Pharmacotherapy Service of The Royal Prince Alfred Hospital (RPAH) to determine the incidence of difficulty with blood collection. This survey identified the need for an innovative venous access strategy to better manage this group of patients. An external jugular venepuncture (EJV) protocol and education package was developed in collaboration with the Department of Anaesthetics, Gastroenterology and Liver Centre and HCV clinical nurse consultants (CNC). RPAH policy and procedure committee approved the protocol and patient information sheet. Patients with a history of difficulty with blood collection were eligible for the protocol. Patient satisfaction surveys were conducted. The initial survey of patients from the liver clinics and pharmacotherapy service identified that 48 percent had difficulty with blood collection from conventional sites. In the period October 2002 to July 2006, 29 patients (89 percent with history of IDU) were referred for EJV assessment. Major indications for EJV were for blood testing for initiation and monitoring of antiviral therapy and ongoing assessment of HCV infected patients. No adverse events resulted from the procedure. All patients surveyed report high levels of satisfaction with the technique compared to previous venous access attempts. EJV improves access to antiviral therapy and is a safe and effective technique for patients with difficult venous access (DVA). In addition, we have utilised EJV for post-transplant care of patients and used external jugular vein cannulation as vascular access for contrast imaging in hepatocellular carcinoma (HCC) assessment.

Mannan binding lectin and viral hepatitis

Mannan binding lectin (MBL) is a pattern recognition molecule of the innate immune system that binds to sugars on the surface of invading micro-organisms. Target binding, complement activation and other functions of MBL are dependent on the presence of multiple carbohydrate recognition domains. Several polymorphisms in the promoter and structural regions of MBL2 adversely affect the plasma concentration and oligomeric state of MBL. The possession of mutant alleles has been linked to disease outcome for a variety of bacterial and viral infections. Viral hepatitis is caused by unrelated viruses referred to as hepatitis virus A-E. The disease usually has both acute and chronic phases, the latter leading to cirrhosis and hepatocellular carcinoma. Hepatitis viruses B and C (HBV and HCV, respectively) are a significant cause of morbidity worldwide. HBV encodes envelope glycoproteins termed large, middle, and small that may exist in glycosylated or unglycosylated forms on the virion. An interaction between HBV glycoproteins and MBL has been demonstrated in vitro. Significant associations between MBL levels, determined by MBL2 haplotypes, and HBV persistence and disease progression have been described. HCV encodes two highly glycosylated envelope proteins, E1 and E2, which are potential targets for interaction with MBL. Mutant MBL2 haplotypes have been linked to disease progression and response to therapy in HCV infection. Here we summarise the effect of MBL2 polymorphisms on MBL function and how this may relate to disease outcome in HBV and HCV infection.

Illness-related stigma, mood and adjustment to illness in persons with hepatitis C

We examined stigma in persons with hepatitis C and its relationship with mood and adjustment to illness. We studied 87 persons awaiting interferon treatment for hepatitis C at St James's Hospital, Dublin. Stigma was assessed using Fife's Experience of Illness scale. A structured clinical interview was used to establish DSM-IV diagnosis. The Hospital Anxiety and Depression Scale (HADS) and Beck Depression Inventory (BDI) were also used as measures of mood. Factor analysis and clustering around latent variables analysis were used to assess scale structure and reliability. The stigma scale had an overall reliability of 0.94. A strong dimension of fear of disclosure emerged, from item analysis, together with dimensions of social isolation and social rejection. Stigma was higher in those in manual occupations and the unemployed than in those in non-manual occupation. There were high levels in those with disease associated with injecting drug use and iatrogenic disease caused by transfusion or anti-D blood products, and low levels in those who had been treated for haemophilia with contaminated products or whose hepatitis was of unknown origin. Adjusted for confounders, a 1-decile increase in stigma score had an odds ratio of 1.4 for DSM-IV depression and similar associations with depression on the HADS and BDI. Stigma was also associated with poorer work and social adjustment, lower acceptance of illness, higher subjective levels of symptoms and greater subjective impairment of memory and concentration. These associations were replicated in the non-depressed subsample. The results underline the strong link between stigma and well-being in hepatitis C. However, they also suggest that stigma is a complex construct that will require further research to elucidate.

Pathogenesis of hepatitis B virus infection

Hepatitis B virus (HBV) consists of a circular, partially double-stranded DNA molecule of 3.2 kb in length, which contains four overlapping reading frames that code for surface proteins (HBsAg), core proteins (HBcAg/HBeAg), the viral polymerase and the transcriptional transactivator X protein. HBV infection can lead to chronic carriage of the virus and progressive liver diseases, such as hepatitis, liver cirrhosis and hepatocellular carcinoma (HCC). HBV and hepatitis C virus or HIV coinfections can increase the HCC risk. A great amount of evidence demonstrates that HBV plays an important role in the development of liver diseases. Chronic hepatitis appears to be due to a suboptimal cellular immune response that destroys some of the infected hepatocytes and does not purge the virus from the remaining infected hepatocytes, thereby permitting the persisting virus to trigger a chronic indolent necroinflammatory liver disease that sets the stage for the development of HCC. However, the pathogenesis of HBV-related HCC is incompletely clarified. Hepatitis B virus X protein (HBx), an important transforming inducer, plays a crucial role in HCC occurrence, invasion and metastasis. Monitoring of the HBV genotypes and antibody to hepatitis B x antigen (anti-HBx) are significant for predicting the outcome of antiviral therapy or early diagnosis of liver cirrhosis and HCC. Some molecular approaches, such as antisense, oligonucleotides, ribozymes, RNA interference targeting HBV mRNA, are available in antiviral therapies. The intracellular antibody technique and immune therapy by dendritic cells could potentially be used in future antiviral therapies.

Arbidol: a broad-spectrum antiviral that inhibits acute and chronic HCV infection

Arbidol (ARB) is an antiviral compound that was originally proven effective for treatment of influenza and several other respiratory viral infections. The broad spectrum of ARB anti-viral activity led us to evaluate its effect on hepatitis C virus (HCV) infection and replication in cell culture. Long-term ARB treatment of Huh7 cells chronically replicating a genomic length genotype 1b replicon resulted in sustained reduction of viral RNA and protein expression, and eventually cured HCV infected cells. Pre-treatment of human hepatoma Huh7.5.1 cells with 15 μM ARB for 24 to 48 hours inhibited acute infection with JFH-1 virus by up to 1000-fold. The inhibitory effect of ARB on HCV was not due to generalized cytotoxicity, nor to augmentation of IFN antiviral signaling pathways, but involved impaired virus-mediated membrane fusion. ARB's affinity for membranes may inhibit several aspects of the HCV lifecycle that are membrane-dependent.