Therapy of hepatitis C: from empiricism to eradication

Ubiquitin-protein ligase E3A (UBE3A) mediation of viral infection and human diseases

The Ubiquitin-protein ligase E3A, UBE3A, also known as E6-associated protein (E6-AP), is known to play an essential role in regulating the degradation of various proteins by transferring Ub from E2 Ub conjugating enzymes to the substrate proteins. Several studies indicate that UBE3A regulates the stabilities of key viral proteins in the virus-infected cells and, thereby, the infected virus-mediated diseases, even if it were reported that UBE3A participates in non-viral-related human diseases. Furthermore, mutations such as deletions and duplications in the maternally inherited gene in the brain cause human neurodevelopmental disorders such as Angelman syndrome (AS) and autism. It is also known that UBE3A functions as a transcriptional coactivator for the expression of steroid hormone receptors. These reports establish that UBE3A is distinguished by its multitudinous functions that are paramount to viral pathology and human diseases. This review is focused on molecular mechanisms for such intensive participation of UBE3A in disease formation and virus regulation.

Performance Evaluation of In Vitro Screening and Diagnostic Kits for Hepatitis C Virus Infection

Aim

A reliable kit with high sensitivity and specificity is indispensable for diagnosing hepatitis C virus (HCV) infection. Detection kits for anti-HCV antibodies (anti-HCV) are used for screening, and quantification kits for HCV RNA and HCV antigen (Ag) are used for the definite diagnosis of HCV infection or the evaluation of the pathological condition of and therapeutic effects in patients with chronic hepatitis C. Several kits are currently available for these purposes and are provided for clinical use in Japan. In this study, we aimed to evaluate the performance of these kits.

Methods

We used International Standards for HCV RNA and HCV Ag and a regional reference panel to evaluate the performance of thirteen anti-HCV, five HCV RNA, and two HCV Ag kits.

Results

All specimens in the regional reference panel were diagnosed correctly by all anti-HCV kits, although the distributions of the quantified values varied, and the ratios of titer classification were not identical across kits. All HCV RNA kits quantified the International Standard with minimum deviation and diagnosed the specimens of the reference panel correctly. The quantified values of the International Standard by two HCV Ag kits were inconsistent. HCV Ag titers of some specimens were underestimated owing to the amino acid polymorphisms in comparison with HCV RNA titers.

Conclusions

The evaluation with International Standards and the regional reference panel was useful for assessing the quality of screening and diagnostic kits for HCV infection, and such quality control is essential for the clinical usage of these kits.

Inhibition of hepatitis C virus by vitamin D

Until the development of direct-acting antivirals (DAAs), interferon (IFN)-based therapy had been the primary treatment strategy for patients with chronic hepatitis C, even though this therapy has a therapeutic limitations and considerable side effects. Therefore, many efforts have been made to improve the efficacy of treatment. Several clinical studies have clearly shown that supplementation with vitamin D of IFN-based therapy improves treatment efficacy. To clarify the molecular mechanisms of the effect of vitamin D on IFN-based therapy, several researchers have performed basic research with cell culture models of hepatitis C virus (HCV). Consequently, two vitamin D₃ metabolites, 25-hydroxyvitamin D₃ (25-(OH)D₃) and 1α,25-dihydroxyvitamin D₃ (1α,25-(OH)₂D₃), have been suggested to have anti-HCV effects. 25-(OH)D₃ inhibits HCV production by suppressing infectious virus assembly through reducing apolipoprotein expression, while 1α,25-(OH)₂D₃ inhibits HCV production by modulating IFN signaling and/or inducing various host factors associated with the inhibition of viral genome replication. In addition, an antimicrobial peptide, LL-37, which is known to be partly regulated by vitamin D, was also reported to exhibit an anti-HCV effect by disrupting infectious viral particles directly. In conclusion, vitamin D₃ supplementation improves the response rate of IFN-based therapy via the direct and/or indirect anti-HCV effects of vitamin D₃ metabolites.

Liver Abnormalities after Elimination of HCV Infection: Persistent Epigenetic and Immunological Perturbations Post-Cure

Chronic hepatitis C (CHC) is a major cause of hepatocellular carcinoma (HCC) worldwide. While directly acting antiviral (DAA) drugs are now able to cure virtually all hepatitis C virus (HCV) infections, even in subjects with advanced liver disease, what happens to the liver and progression of the disease after DAA-induced cure of viremia is only beginning to emerge. Several large-scale clinical studies in different patient populations have shown that patients with advanced liver disease maintain a risk for developing HCC even when the original instigator, the virus, is eliminated by DAAs. Here we review emerging studies derived from multiple, complementary experimental systems involving patient liver tissues, human liver cell cultures, human liver slice cultures, and animal models, showing that HCV infection induces epigenetic, signaling, and gene expression changes in the liver associated with altered hepatic innate immunity and liver cancer risk. Of critical importance is the fact that these virus-induced abnormalities persist after DAA cure of HCV. These nascent findings portend the discovery of pathways involved in post-HCV immunopathogenesis, which may be clinically actionable targets for more comprehensive care of DAA-cured individuals.

Management of Hepatitis C in Children and Adolescents

The management of hepatitis C virus (HCV) infections has changed dramatically in recent years with the use of direct antiviral agents (AADs). New AADs have excellent safety profile and demonstrated to be highly effective. Interferon free regimens are now recommended for children and adolescents but significant barriers for treatment exist. Overcoming those barriers will facilitate HCV elimination. This review covers varied topics to familiarize providers with the current status of pediatric HCV management in light of newly available DAAs medications.

Short article: Hepatitis C and G virus coinfection in Punjab, Pakistan: incidence and its correlation analysis with clinical data

INTRODUCTION

Hepatitis G virus (HGV) infection appears to be common in patients with chronic hepatitis C virus (HCV) infection. The aim of this study was to investigate the prevalence of HCV/HGV in patients with chronic hepatitis C (CHC) in Pakistan and to look for possible associations with various clinical and histopathological changes in HCV/HGV coinfection and HCV infection.

PATIENTS AND METHODS

The present study included 136 patients. Clinical, biochemical, virological and histological findings were compared between patients coinfected with HCV/HGV and patients with HCV alone.

RESULTS

Of the 136 patients with CHC, 16 (11.76%) were coinfected with HCV/HGV. The mean age of coinfected patients was lower than in patients with HCV alone. HCV/HGV coinfected patients did not show significant differences in sex, clinical presentation, biochemical markers, and liver fibrosis as compared to those with HCV infection. Only the mean values of platelets count, mean corpuscular hemoglobin (MCH), and MCH concentration markers were significantly different in HCV/HGV coinfected patients as compare to patients with HCV alone.

CONCLUSION

It was found that 11.76% of patients with CHC in Pakistan were associated with HCV/HGV coinfection. No significant differences were observed in clinical and histological features except for platelets count, MCH, and MCH concentration markers between HCV and HGV coinfected patients in comparison with HCV-infected patients.

A review on HCV inhibitors: Significance of non-structural polyproteins

Hepatitis C virus (HCV) mortality and morbidity is a world health misery with an approximate 130–150 million chronically HCV tainted and suffering individuals and it initiate critical liver malfunction like cirrhosis, hepatocellular carcinoma or liver HCV cancer. HCV NS5B protein one of the best studied therapeutic target for the identification of new drug candidates to be added to the combination or multiple combination medication recently approved. During the past few years, NS5B has thus been an important object of attractive medicinal chemistry endeavors, which induced to the surfacing of betrothal preclinical drug molecules. In this scenario, the current review set limit to discuss research published on NS5B and few other therapeutic functional inhibitors concentrating on hit investigation, hit to lead optimization, ADME parameters evaluation, and the SAR data which was out for each compound type and similarity taken into consideration. The discussion outlined in this specific review will surly helpful and vital tool for those medicinal chemists investigators working with HCV research programs mainly pointing on NS5B and set broad spectrum identification of creative anti HCV compounds. This mini review also tells each and every individual compound ability related how much they are active against NS5B and few other targets.

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Hepatitis C infection causes severe liver cirrhosis and carcinoma.

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The new acute HCV infections are raising every year and mortality rate become serious concern.

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The plausible list of anti-HCV drugs and clinical agents were listed in this review.

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The divergent medicinal scaffolds as anti-HCV agents were presented as per their targets.

Vitamin D derivatives inhibit hepatitis C virus production through the suppression of apolipoprotein

Supplementation with vitamin D (VD) has been reported to improve the efficacy of interferon-based therapy for chronic hepatitis C. We found that 25-hydroxyvitamin D₃ (25-(OH)D₃), one of the metabolites of VD, has antiviral effects by inhibiting the infectious virus production of the hepatitis C virus (HCV). In this study, to clarify the underlying mechanisms of the anti-HCV effects, we searched VD derivatives that have anti-HCV effects and identified the common target molecule in the HCV life cycle by using an HCV cell culture system. After infection of Huh-7.5.1 cells with cell culture-generated HCV, VD derivatives were added to culture media, and the propagation of HCV was assessed by measuring the HCV core antigen levels in culture media and cell lysates. To determine the step in the HCV life cycle affected by these compounds, the single-cycle virus production assay was used with a CD81-negative cell line. Of the 14 structural derivatives of VD, an anti-HCV effect was detected in 9 compounds. Cell viability was not affected by these effective compounds. The 2 representative VD derivatives inhibited the infectious virus production in the single-cycle virus production assay. Treatment with these compounds and 25-(OH)D₃ suppressed the expression of apolipoprotein A1 and C3, which are known to be involved in infectious virus production of HCV, and the knockdown of these apolipoproteins reduced infectious virus production. In conclusion, we identified several compounds with anti-HCV activity by screening VD derivatives. These compounds reduce the infectious virus production of HCV by suppressing the expression of apolipoproteins in host cells.

Induction of humoural and cellular immunity by immunisation with HCV particle vaccine in a non-human primate model

OBJECTIVE

Although HCV is a major cause of chronic liver disease worldwide, there is currently no prophylactic vaccine for this virus. Thus, the development of an HCV vaccine that can induce both humoural and cellular immunity is urgently needed. To create an effective HCV vaccine, we evaluated neutralising antibody induction and cellular immune responses following the immunisation of a non-human primate model with cell culture-generated HCV (HCVcc).

DESIGN

To accomplish this, 10 common marmosets were immunised with purified, inactivated HCVcc in combination with two different adjuvants: the classically used aluminum hydroxide (Alum) and the recently established adjuvant: CpG oligodeoxynucleotide (ODN) wrapped by schizophyllan (K3-SPG).

RESULTS

The coadministration of HCVcc with K3-SPG efficiently induced immune responses against HCV, as demonstrated by the production of antibodies with specific neutralising activity against chimaeric HCVcc with structural proteins from multiple HCV genotypes (1a, 1b, 2a and 3a). The induction of cellular immunity was also demonstrated by the production of interferon-γ mRNA in spleen cells following stimulation with the HCV core protein. These changes were not observed following immunisation with HCVcc/Alum preparation. No vaccination-related abnormalities were detected in any of the immunised animals.

CONCLUSIONS

The current preclinical study demonstrated that a vaccine included both HCVcc and K3-SPG induced humoural and cellular immunity in marmosets. Vaccination with this combination resulted in the production of antibodies exhibiting cross-neutralising activity against multiple HCV genotypes. Based on these findings, the vaccine created in this study represents a promising, potent and safe prophylactic option against HCV.

Establishment of a platform for molecular and immunological characterization of the RNA-dependent-RNA-polymerase NS5B of an Egyptian HCV isolate

The present work aimed at establishing a platform to enable frequent characterization of the HCV RNA-dependent-RNA-polymerase from Egyptian clinical isolates. Subjecting amplified HCV-NS5B coding gene from Egyptian patient's serum to sequencing, multiple alignment, and phylogenetic analysis confirmed its subtype 4a origin. Nucleotide sequence analysis revealed presence of an additional start codon at the beginning of the NS5B gene. Peptide sequence alignment demonstrated presence of unique amino acid residues in our 4a-NS5B sequence distinct from the JFH-1-NS5B sequence as well as unique amino acids compared to other genotypes. The distinct molecular structure of the herein characterized 4a-NS5B from the 2a-JFH-1-NS5B was further demonstrated both in the built 3D models and the Ramachandran plots corresponding to each structure. Both the unique amino acid residues and 3D structure of the 4a-NS5B may influence both genotype 4a replication rate and response to therapy in comparison to other genotypes. Many resistance mutations to polymerase inhibitors were found both in ours and other genotypes' sequences. The presence of the required amino acid motifs for the RNA dependent RNA polymerase activity encouraged to clone the NS5B570-encoding sequence downstream CMV promotor in a mammalian expression vector. Such construct was used for both prokaryotic expression in bacteria and for DNA immunization. Successful mammalian expression and induction of specific immune response were demonstrated by ELISA and Western blotting. The potential of both the raised antibodies and the expressed NS5B to differentiate between HCV-infected and control human sera were demonstrated which reflect their diagnostic value.

Pharmacist engagement within a hepatitis C ambulatory care clinic in the era of a treatment revolution

OBJECTIVES

To describe an innovative hepatitis C virus (HCV) care program and treatment outcomes resulting from pharmacist services.

SETTING

Adult ambulatory care HCV clinic within the Miami Veteran Affairs Healthcare System.

PRACTICE DESCRIPTION

Pharmacists with limited prescriptive authority are integrated into a medical hepatology care team.

PRACTICE INNOVATION

Pharmacists screen patients with HCV infection for treatment eligibility, counsel patients upon treatment initiation, assess ongoing treatment success and toxicity through patient appointments, telephone calls, and the ordering of pertinent laboratory data, and provide oversight of all patients on HCV therapies. Treatment outcomes are reported to the institutional Antimicrobial Stewardship Program.

EVALUATION

Data produced from a continuous quality assurance initiative were utilized. Descriptive statistics were used to present data.

RESULTS

From January 2014 through September 2015 there were 1619 pharmacist encounters for 532 unique patients and 597 screenings (including 578 approvals) were completed by a pharmacist. During this time 555 patients were initiated on at least 1 HCV treatment course, with 565 total treatment courses initiated. As new agents became available for use, fluctuation in regimen selection was seen. The most commonly prescribed medications were sofosbuvir (46%), ledipasvir/sofosbuvir (37%), and simeprevir (33%). Of the 565 HCV treatment courses initiated, 360 were completed, 29 were stopped early during treatment, and 176 were ongoing. Of the 360 completed courses, 249 had sustained virologic response at week 12 results available, of which 225 (90%) achieved treatment success and 24 (10%) relapsed. Of the 29 courses stopped early, 11 were due to poor medication adherence and 8 were due to adverse drug reaction.

CONCLUSION

Through a structured process employing a scope of practice, pharmacists can extend the capacity of medical hepatology providers and provide pharmacotherapy services to enhance care. Information provided here may serve beneficial to others looking to initiate or expand existing HCV pharmacist services.

Antimicrobial peptide LL-37 attenuates infection of hepatitis C virus

AIM

Although recent studies indicate that supplementation with vitamin D (VD) potentiates a sustained viral response by interferon-based therapy to chronic hepatitis C, detailed mechanisms are not fully defined. The production of cathelicidin, an antimicrobial peptide, has been demonstrated to be part of the VD-dependent antimicrobial pathway in innate immunity. Cathelicidin is known to directly kill or inhibit the growth of microbial pathogens including mycobacteria and viruses.

METHODS

We used a hepatitis C virus (HCV) cell culture system to clarify the anti-HCV effects of the human cathelicidin, LL-37. HuH-7 cells were administrated with LL-37 and infected with cell culture-generated HCV (HCVcc). HCV propagation was estimated by measuring the level of HCV core antigen (Ag).

RESULTS

Treatment with LL-37 resulted in decreased intra- and extracellular levels of HCV core Ag, suggesting inhibition of HCV propagation. To assess the effects of LL-37 on HCV replication, JFH-1 subgenomic replicon RNA-transfected cells were treated with LL-37. However, inhibition of HCV replication was not detected by this assay. To clarify the effects on HCV infection, we treated HCVcc with LL-37 and removed the antimicrobial peptide prior to use of the virus in infection. This exposure of HCVcc to LL-37 diminished the infectivity titers in a dose-dependent fashion. Iodixanol density gradient analysis revealed that the peak fraction of infectivity titer was eliminated by LL-37 treatment.

CONCLUSION

The VD-associated antimicrobial peptide LL-37 attenuated the infectivity of HCV. This anti-HCV effect of LL-37 may explain the contribution of VD to the improved efficacy of interferon-based therapy.

Completion of the Entire Hepatitis C Virus Life Cycle in Vero Cells Derived from Monkey Kidney

A hepatitis C virus (HCV) cell culture system incorporating the JFH-1 strain and the human hepatoma cell line HuH-7 enabled the production of infectious HCV particles. Several host factors were identified as essential for HCV replication. Supplementation of these factors in nonhepatic human cell lines enabled HCV replication and particle production. Vero cells established from monkey kidney are commonly used for the production of vaccines against a variety of viruses. In this study, we aimed to establish a novel Vero cell line to reconstruct the HCV life cycle. Unmodified Vero cells did not allow HCV infection or replication. The expression of microRNA 122 (miR-122), an essential factor for HCV replication, is notably low in Vero cells. Therefore, we supplemented Vero cells with miR-122 and found that HCV replication was enhanced. However, Vero cells that expressed miR-122 still did not allow HCV infection. We supplemented HCV receptor molecules and found that scavenger receptor class B type I (SRBI) was essential for HCV infection in Vero cells. The supplementation of apolipoprotein E (ApoE), a host factor important for virus production, enabled the production of infectious virus in Vero cells. Finally, we created a Vero cell line that expressed the essential factors miR-122, SRBI, and ApoE; the entire HCV life cycle, including infection, replication, and infectious virus production, was completed in these cells. In conclusion, we demonstrated that miR-122, SRBI, and ApoE were necessary and sufficient for the completion of the entire HCV life cycle in nonhuman, nonhepatic Vero cells.

HCV is a major cause of chronic liver diseases worldwide, and an effective prophylactic HCV vaccine is needed. For safety reasons, the current HCV cell culture system using HuH-7 cells, which was established from a hepatocellular carcinoma, is not suitable for the production of a vaccine against HCV. A robust HCV production system using non-cancer-derived cells is indispensable for this purpose. In this study, we wanted to establish a novel HCV cell culture system using Vero cells, which are widely used in the production of vaccines against different viruses. We identified the minimum essential host factors for the completion of the entire HCV life cycle in Vero cells to develop a novel HCV cell culture system. A cell culture system that uses Vero cells will be useful not only for HCV vaccine production but also for the further elucidation of the mechanisms of various HCV-host interactions.

Systematic review of the in vitro effects of statins on oral and perioral microorganisms

Statins are medications administered orally and are widely used for lowering the blood cholesterol level. The aim of this study was to investigate the effects of orally administered statins on microorganisms infecting oral and perioral tissues. We performed a systematic review of published studies of the in vitro antimicrobial effects of statins on bacteria, viruses, and fungi, and searched PubMed, Web of Science, Cochrane Central, and Google scholar. Studies show that most statins exhibit antimicrobial effects against various oral microorganisms. Simvastatin is most effective against the periodontal pathogens Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis, and against most dental plaque bacteria, including Streptococcus mutans. Statins also exhibit antiviral properties against human cytomegalovirus, hepatitis B virus, and hepatitis C virus, and have antifungal properties against Candida albicans, Aspergillus fumigatus, and Zygomycetes spp. There were notable differences in the minimum inhibitory concentrations (MICs) between different studies, which may be attributed to differences in study design. Further studies are warranted to ascertain if statins can be solubilized so that patients, who have been prescribed statins for cardiovascular diseases, can use the medication as a swish and swallow, giving patients the added benefit of the antimicrobial action topically in the mouth against infectious oral diseases.

A New Twist to a Chronic HCV Infection: Occult Hepatitis C

Background. The prevalence of occult hepatitis C infection (OCI) in the population of HCV-RNA negative but anti-HCV positive individuals is presently unknown. OCI may be responsible for clinically overt recurrent disease following an apparent sustained viral response (SVR) weeks to years later. Purpose. To review the available current literature regarding OCI, prevalence, pathogenic mechanisms, clinical characteristics, and future directions. Data Sources. Searching MEDLINE, article references, and national and international meeting abstracts for the diagnosis of OCI (1990-2014). Data Synthesis. The long-term followup of individuals with an OCI suggests that the infection can be transient with the loss of detectable HCV-RNA in PPBMCs after 12-18 months or alternatively exist intermittently and potentially long term. The ultimate outcome of HCV infection is decided by interplay between host immune responses, antiviral therapies, and the various well-identified viral evasion mechanisms as well as the presence of HCV infection within extrahepatic tissues. Conclusion. The currently widely held assumption of a HCV-cure in individuals having had "SVR" after 8-12 weeks of a course of DAA therapy as recently defined may not be entirely valid. Careful longitudinal followup utilizing highly sensitive assays and unique approaches to viral isolation are needed.

Mitochondrial DNAs decreased and correlated with clinical features in HCV patients from Yunnan, China

Hepatitis C was the most popular chronic infectious liver disease worldwide. It was identified that Hepatitis C virus (HCV) infection could lead to mitochondrial dysfunction, though the mechanism was not fully understood. To investigate whether mtDNA copy number could be affected by HCV infection and be associated with clinical features of HCV patients, mtDNA copy numbers were analyzed in 242 patients with HCV infection and 226 matched control samples. The results suggested that mtDNA copy numbers significantly decreased in HCV patients (68.80 ± 3.33) than in control samples (81.54 ± 4.50) (p = 0.022). When males/females were separated from total patients to compare mtDNA copy numbers with gender matched controls, mtDNA copy numbers still significantly decreased in male HCV patients (p = 0.002). Further analysis indicated that level of high-density lipoprotein cholesterol (HDL-C) was negatively correlated with mtDNA copy numbers in total HCV patients (r = -0.128, p = 0.047), and this correlation was more significant in male HCV patients (r = -0.266, p = 0.030). Intriguingly, aspartate amino-transferase (AST) showed positive correlation with mtDNA copy numbers (r = 0.260, p = 0.034) in male HCV patients. Our results indicated that mtDNA copy numbers depleted and correlated with clinical features in male HCV patients.

Effect of vitamin D therapy on interleukin-6, visfatin, and hyaluronic acid levels in chronic hepatitis C Egyptian patients

Objectives

We aimed to compare serum levels of interleukin-6, visfatin, and hyaluronic acid in chronic hepatitis C Egyptian patients who received standard of care (SOC) therapy for chronic hepatitis C virus (HCV) consisting of pegylated interferon (PEG-IFN) and ribavirin (RBV) and in those who received SOC with vitamin D (vit D) for 48 weeks in HCV genotype 4a subjects.

Design and methods

One hundred chronic HCV patients were classified into two groups: study 50 patients received SOC therapy PEG-IFN/RBV + vit D and control 50 patients received SOC PEG-IFN/RBV without vit D. Both groups were followed up at 12 weeks, 24 weeks, and 48 weeks of treatment.

Results

Results showed a significant elevation in vit D levels in the group treated with SOC and vit D compared to SOC group and a reduction in HCV RNA from the 12th week to reach zero level in the 24th week. Interleukin-6, visfatin, and hyaluronic acid levels were also reduced significantly. Alanine transaminase and aspartate transaminase biomarkers were significantly reduced, indicating decreased liver injury.

Conclusion

SOC PEG-IFN/RBV + vit D therapy for chronic HCV led to reduced interleukin-6, visfatin, and hyaluronic acid levels and follow up liver biochemical biomarkers as aspartate transaminase and alanine transaminase indicates proper liver healing and monitoring.

Effect of the infectious dose and the presence of hepatitis C virus core gene on mouse intrahepatic CD8 T cells

AIM

Chronic hepatitis C viral (HCV) infections often result in ineffective CD8 T-cell responses due to functional exhaustion of HCV-specific T cells. However, how persisting HCV impacts CD8 T-cell effector functions remains largely unknown. The aim of this study is to examine the effect of the infectious dose and the presence of HCV core gene.

METHODS

We compared responses of intrahepatic CD8 T cells during infection of wild-type or HCV core transgenic (Tg) mice with various infectious doses of HCV-NS3-expressing recombinant adenovirus (Ad-HCV-NS3).

RESULTS

Using major histocompatibility complex class I tetramer and intracellular interferon (IFN)-γ staining method to track HCV-NS3-specific CD8 T cells, we found that a significant expansion of HCV-NS3-specific CD8 T cells was restricted to a very narrow dosage range. IFN-γ production by intrahepatic CD8 T cells in HCV core Tg mice was suppressed as compared with wild-type mice. Higher levels of expression of regulatory molecules, Tim-3 and PD-1, by intrahepatic CD8 T cells and PD-L1 by intrahepatic antigen-presenting cells were observed in HCV core Tg mice following Ad-HCV-NS3 infection, and the expression increased dependent on infectious dose. Furthermore, we found a significant inverse correlation between the percentages of IFN-γ-producing cells and expression of regulatory molecules in antigen-specific intrahepatic CD8 T cells.

CONCLUSION

High infectious dose and the presence of HCV core gene were strongly involved in ineffective CD8 T-cell responses. We consider that HCV core Tg mouse infected with high infectious dose of Ad-HCV-NS3 is useful as a chronic infection model in the development of immunotherapy for chronic hepatitis C.

Occurrence of genetic modifications in core, 5'UTR and NS5b of HCV associated with viral response to treatment

Background

It is becoming progressively more understandable that genetic variability of viruses is a major challenge in translating the laboratory findings to clinic. Genetic variability is the underlying cause of variant viral proteins which are not targetable by host immunological machinery.

Methods

500 patients were enrolled in study and amongst them, 451 patients were followed and categorized into two groups on the basis of their treatment response. Group 1 consisting of the 376 patients exhibited SVR while group 2 comprised 75 patients who were non-responders on the basis of viral load as evidenced by Real-Time PCR. Comparative sequence analysis was done between 75 non-responders and 75 responders (randomly picked from 376) by targeting three genomic regions, 5′UTR, core and NS5B and amplified products were directly sequenced and obtained sequences were cleaned, aligned and submitted to GenBank. Maximum Parsimony (MP) method was used for phylogenetic analysis and dendrograms were dragged using MEGA 5. Heterogeneity at nucleotide and amino acid level was determined using software BioEdit and DNAman while phosphorylation and N-linked glycosylation sites were determined using NetPhos 2.0 and SignalP-NN.

Results

Genotype 3 was prevalent in group 1 whereas non-responders indicated rare genotypes of Pakistan i.e. 4 and 5, genotype 6q and 6v were reported first time from Pakistan in this study. At nucleotide and amino acid level, the genetic distance and mutation, number of predicted N-phosphorylation and N-glycosylation sites was higher in group 2 as compared to group 1. Difference in percentage composition of individual amino acids was noted to be different between the two groups.

Conclusions

It can be concluded that heterogeneity both at nucleotide and amino acid level contributed in developing drug resistant phenotype. Moreover, occurrence of rare genotypes might hurdle the way to positive response of conventional treatment. Furthermore, prediction of phosphorylation and glycosylation sites could help in targeting the proper sites for drug designing.

Protective role of amantadine in mitochondrial dysfunction and oxidative stress mediated by hepatitis C virus protein expression

Amantadine is an antiviral and antiparkinsonian drug that has been evaluated in combination therapies against hepatitis C virus (HCV) infection. Controversial results have been reported concerning its efficacy, and its mechanism of action remains unclear. Data obtained in vitro suggested a role of amantadine in inhibiting HCV p7-mediated cation conductance. In keeping with the fact that mitochondria are responsible to ionic fluxes and that HCV infection impairs mitochondrial function, we investigated a potential role of amantadine in modulating mitochondrial function. Using a well-characterized inducible cell line expressing the full-length HCV polyprotein, we found that amantadine not only prevented but also rescued HCV protein-mediated mitochondrial dysfunction. Specifically, amantadine corrected (i) overload of mitochondrial Ca²⁺; (ii) inhibition of respiratory chain activity and oxidative phosphorylation; (iii) reduction of membrane potential; and (iv) overproduction of reactive oxygen species. The effects of amantadine were observed within 15 min following drug administration and confirmed in Huh-7.5 cells transfected with an infectious HCV genome. These effects were also observed in cells expressing subgenomic HCV constructs, indicating that they are not mediated or only in part mediated by p7. Single organelle analyzes carried out on isolated mouse liver mitochondria demonstrated that amantadine induces hyperpolarization of the membrane potential. Moreover, amantadine treatment increased the calcium threshold required to trigger mitochondrial permeability transition opening. In conclusion, these results support a role of amantadine in preserving cellular bioenergetics and redox homeostasis in HCV-infected cells and unveil an effect of the drug which might be exploited for a broader therapeutic utilization.

Regulation of gene expression by microRNA in HCV infection and HCV-mediated hepatocellular carcinoma

MicroRNA (miRNA) exert a profound effect on Hepatitis C virus (HCV) replication and on the manifestation of HCV-associated hepatocellular carcinoma (HCC). miR-122 in particular, is highly enriched in liver and has been shown to interact with HCV, suggesting this virus has evolved to subvert and manipulate the host gene silencing machinery in order to support its life cycle. It is therefore likely that miR-122 and other miRNAs play an important role in the pathophysiology of HCV infection. The changes in post-transcriptional gene regulation by the miRNAs may play a key role in the manifestation of chronic liver disease and hepatocellular carcinoma. Understanding of HCV-host miRNA interactions will ultimately lead to the design of therapeutic modalities against HCV infection and HCV-mediated HCC and may also provide important biomarkers that direct treatment options. Here, we review the current knowledge on the role of miRNA and gene expression on HCV infection and hepatocellular carcinoma, in addition to the possible role of miRNA as future therapeutic targets.

Whey-hydrolyzed peptide-enriched immunomodulating diet prevents progression of liver cirrhosis in rats

OBJECTIVE

Liver fibrosis and subsequent cirrhosis is a major cause of death worldwide, but few effective antifibrotic therapies are reported. Whey-hydrolyzed peptide (WHP), a major peptide component of bovine milk, exerts anti-inflammatory effects in experimental models. A WHP-enriched diet is widely used for immunomodulating diets (IMD) in clinical fields. However, the effects of WHP on liver fibrosis remain unknown. The aim of this study was to investigate the antifibrotic effects of WHP in a rat cirrhosis model.

METHODS

Progressive liver fibrosis was induced by repeated intraperitoneal administration of dimethylnitrosamine (DMN) for 3 wk. Rats were fed either a WHP-enriched IMD (WHP group) or a control enteral diet (control group). The degree of liver fibrosis was compared between groups. Hepatocyte-protective effects were examined using hepatocytes isolated from rats fed a WHP diet. Reactive oxygen species and glutathione in liver tissue were investigated in the DMN cirrhosis model.

RESULTS

Macroscopic and microscopic progression of liver fibrosis was remarkably suppressed in the WHP group. Elevated serum levels of liver enzymes and hyaluronic acid, and liver tissue hydroxyproline content were significantly attenuated in the WHP group. Necrotic hepatocyte rates with DMN challenge, isolated from rats fed a WHP-enriched IMD, were significantly lower. In the DMN cirrhosis model, reactive oxygen species were significantly lower, and glutathione was significantly higher in the WHP group's whole liver tissue.

CONCLUSION

A WHP-enriched IMD effectively prevented progression of DMN-induced liver fibrosis in rats via a direct hepatocyte-protective effect and an antioxidant effect through glutathione synthesis.

The long-term effects of splenectomy and subsequent interferon therapy in patients with HCV-related liver cirrhosis

Partial splenic embolization (PSE) or splenectomy is widely performed to increase platelet counts for interferon (IFN) therapy. The aim of the present study was to evaluate the long-term effects of splenectomy and subsequent IFN therapy in patients with hepatitis C virus (HCV)-related liver cirrhosis (LC). The present study included 19 patients with HCV-related LC who underwent splenectomy for thrombo-cytopenia caused by hypersplenism. IFN therapy was performed in all 19 patients. The effects of splenectomy and subsequent IFN therapy on peripheral blood counts, liver function, carcinogenesis and survival rates were evaluated. Splenectomy was safely performed in all patients without major complications with the exception of portal thrombosis, which, however, it did not affect liver function when treated appropriately. Thrombocytopenia improved and IFN therapy could be performed in all the patients. A sustained virological response (SVR) was not observed in patients with genotype 1 although it was observed in 75% of patients with genotype 2. Due to severe side effects, five patients did not undergo scheduled IFN therapy. Over 5 years, the mean platelet number increased from 5.2 x 10(4) to 16.8 x 10(4)/mm3 (P<0.01) and liver function improved following splenectomy (albumin, Alb: 3.5‑3.8 g/dl; total bilirubin, T-Bil: 1.0‑0.7 mg/dl; prothrombin time, PT: 74.1‑97.7%; total cholesterol; T-cho: 140‑168 mg/dl; P<0.05). Hepatocellular carcinoma (HCC) occurred in only one patient during long‑term observation and follow‑up of the patients not presenting with HCC at entry. The results of the present study demonstrate that splenectomy followed by interferon therapy could be beneficial in patients with HCV-related LC.

Therapeutic DNA vaccination using in vivo electroporation followed by standard of care therapy in patients with genotype 1 chronic hepatitis C

Clearance of infections caused by the hepatitis C virus (HCV) correlates with HCV-specific T cell function. We therefore evaluated therapeutic vaccination in 12 patients with chronic HCV infection. Eight patients also underwent a subsequent standard-of-care (SOC) therapy with pegylated interferon (IFN) and ribavirin. The phase I/IIa clinical trial was performed in treatment naive HCV genotype 1 patients, receiving four monthly vaccinations in the deltoid muscles with 167, 500, or 1,500 μg codon-optimized HCV nonstructural (NS) 3/4A-expressing DNA vaccine delivered by in vivo electroporation (EP). Enrollment was done with 2 weeks interval between patients for safety reasons. Treatment was safe and well tolerated. The vaccinations significantly improved IFN-γ-producing responses to HCV NS3 during the first 6 weeks of therapy. Five patients experienced 2-10 weeks 0.6-2.4 log10 reduction in serum HCV RNA. Six out of eight patients starting SOC therapy within 1-30 months after the last vaccine dose were cured. This first-in-man therapeutic HCV DNA vaccine study with the vaccine delivered by in vivo EP shows transient effects in patients with chronic HCV genotype 1 infection. The interesting result noted after SOC therapy suggests that therapeutic vaccination can be explored in a combination with SOC treatment.

Advanced fibrosis is not a negative pretreatment predictive factor for genotype 2 or 3 chronic hepatitis C patients

Background/Aims

Chronic hepatitis C patients with advanced fibrosis have unsatisfactory sustained virological response (SVR) rates. Few data demonstrating the efficacy of combination therapy in chronic hepatitis C patients with advanced fibrosis in South Korea are available. The purpose of this study was to assess whether the stage of fibrosis impacts the efficacy of combination therapy for chronic hepatitis C.

Methods

We retrospectively reviewed data for a total of 109 patients with chronic hepatitis C, treated with peginterferon alfa and ribavirin. SVR according to the stage of liver fibrosis assessed by pretreatment liver biopsy and genotype results were analyzed.

Results

Data from 66 genotype 1 patients (60.6%) and 43 genotype 2 or 3 patients (39.4%) among the 109 patients were analyzed. SVR rates for the genotype 1 patients were significantly lower for the stage 3-4 group (32.1%) than the stage 0-2 group (78.9%; P<0.001). SVR rates (92.0% for stage 0-2, 77.8% for stage 3-4, P=0.184) of genotype 2 or 3 patients were not significantly different according to fibrosis stage. Likewise, the frequency of adverse events was not significantly different according to fibrosis stage.

Conclusions

Compared to patients without advanced fibrosis, we can anticipate good SVR rates for genotype 2 or 3 patients with advanced fibrosis and they did not show an inferior tolerability for peginterferon and ribavirin combination therpy. Our results suggest that active treatment is needed for genotype 2 or 3 patients with advanced fibrosis.

Xanthohumol, a main prenylated chalcone from hops, reduces liver damage and modulates oxidative reaction and apoptosis in hepatitis C virus infected Tupaia belangeri

Hepatitis C virus (HCV) infection in Tupaia belangeri (Tupaia) represents an important model of HCV infection. Xanthohumol (XN), a major prenylated chalcone from hops, has various biological activities including hepatopreventive and anti-viral activities. In this study, Tupaias infected with HCV RNA positive serum were used to evaluate the effects of XN on liver damage, oxidative reaction, apoptosis and viral protein expression in liver tissues. The Tupaias inoculated with HCV positive serum had elevated serum aminotransferase levels and inflammation, especially hepatic steatosis, and HCV core protein expression in liver tissue. In the animals inoculated with HCV positive serum, XN significantly decreased aminotransferase levels, histological activity index, hepatic steatosis score and transforming growth factor β1 expression in liver tissue compared with the animals without XN intervention. XN reduced HCV core protein expression in liver tissue compared with those without XN intervention but the difference was not significant. XN significantly decreased malondialdehyde, potentiated superoxide dismutase and glutathione peroxidase, reduced Bax expression, promoted Bcl-xL and inhibited caspase 3 activity in liver tissues compared with the animals without XN intervention. These results indicate that XN may effectively improve hepatic inflammation, steatosis and fibrosis induced by HCV in Tupaias primarily through inhibition of oxidative reaction and regulation of apoptosis and possible suppression of hepatic stellate cell activation. The anti-HCV potential of XN needs further investigation.

Enantioselective synthesis of derivatives and structure-activity relationship study in the development of NA255 as a novel host-targeting anti-HCV agent

Hepatitis C virus (HCV) infection represents a serious health-care problem. Previously we reported the identification of NA255 from our natural products library using a HCV sub-genomic replicon cell culture system. Herein, we report how the absolute stereochemistry of NA255 was determined and an enantioselective synthetic method for NA255 derivatives was developed. The structure-activity relationship of the NA255 derivatives and rat pharmacokinetic profiles of the representative compounds are disclosed.

Coupling to the surface of liposomes alters the immunogenicity of hepatitis C virus-derived peptides and confers sterile immunity

We have previously demonstrated that antigens chemically coupled to the surface of liposomes consisting of unsaturated fatty acids were cross-presented by antigen presenting cells to cytotoxic T lymphocytes (CTLs). Liposomal form of immunodominant CTL epitope peptides derived from lymphocytic choriomeningitis virus exhibited highly efficient antiviral CTL responses in immunized mice. In this study, we coupled 15 highly conserved immunodominant CTL epitope peptides derived from hepatitis C virus (HCV) to the surface of liposomes. We also emulsified the peptides in incomplete Freund’s adjuvant, and compared the immune responses of the two methods of presenting the peptides by cytotoxicity induction and interferon-gamma (IFN-γ) production by CD8⁺ T cells of the immunized mice. We noticed significant variations of the immunogenicity of each peptide between the two antigen delivery systems. In addition, the immunogenicity profiles of the peptides were also different from those observed in the mice infected with recombinant adenoviruses expressing HCV proteins as previously reported. Induction of anti-viral immunity by liposomal peptides was tested by the challenge experiments using recombinant vaccinia viruses expressing corresponding HCV epitopes. One D^b-restricted and three HLA-A^*0201-restricted HCV CTL epitope peptides on the surface of liposomes were found to confer complete protection to immunized mice with establishment of long-term memory. Interestingly, their protective efficacy seemed to correlate with the induction of IFN-γ producing cells rather than the cytotoxicity induction suggesting that the immunized mice were protected through non-cytolytic mechanisms. Thus, these liposomal peptides might be useful as HCV vaccines not only for prevention but also for therapeutic use.

25-Hydroxyvitamin D3 suppresses hepatitis C virus production

Because the current interferon (IFN)-based treatment for hepatitis C virus (HCV) infection has a therapeutic limitation and side effects, a more efficient therapeutic strategy is desired. Recent studies show that supplementation of vitamin D significantly improves sustained viral response via IFN-based therapy. However, mechanisms and an active molecular form of vitamin D for its anti-HCV effects have not been fully clarified. To address these questions, we infected HuH-7 cells with cell culture-generated HCV in the presence or absence of vitamin D(3) or its metabolites. To our surprise, 25-hydroxyvitamin D(3) [25(OH)D(3) ], but not vitamin D(3) or 1,25-dihydroxyvitamin D(3) , reduced the extra- and intracellular levels of HCV core antigen in a concentration-dependent manner. Single-cycle virus production assay with a CD81-negative cell line reveals that the inhibitory effect of 25(OH)D(3) is at the level of infectious virus assembly but not entry or replication. Long-term 25(OH)D(3) treatment generates a HCV mutant with acquired resistance to 25(OH)D(3) , and this mutation resulting in a N1279Y substitution in the nonstructural region 3 helicase domain is responsible for the resistance.

CONCLUSION

25(OH)D(3) is a novel anti-HCV agent that targets an infectious viral particle assembly step. This finding provides insight into the improved efficacy of anti-HCV treatment via the combination of vitamin D(3) and IFN. Our results also suggest that 25(OH)D(3) , not vitamin D(3) , is a better therapeutic option in patients with hepatic dysfunction and reduced enzymatic activity for generation of 25(OH)D(3) .

Boceprevir and personalized medicine in hepatitis C virus infection

Boceprevir was the first agent, along with telaprevir, of a novel class of direct-acting antivirals that entered clinical practice for the treatment of chronic hepatitis C. Boceprevir is an antiprotease that directly blocks hepatitis C virus (HCV) replication. Two studies in patients with HCV genotype 1 infection have shown that addition of boceprevir to the standard of care, ie, pegylated interferon-alfa (PEG-IFN-α) and ribavirin, markedly increased the rate of sustained virological response. A sustained virological response was obtained in about 70% of patients who had never been treated, as well as in 69%-75% and 40% of previous relapsers and nonresponders to PEG-IFN-α-ribavirin, respectively. Side effects were observed in almost all treated patients. Anemia, the most frequent adverse event related to administration of boceprevir, occurred in about 50% of patients. The decision to add boceprevir to the standard of care is made on an individual basis, and takes into account the prognosis of the liver disease, the efficacy of therapy, as it could be at best predicted, and the side effects that may arise, taking into account the comorbidities of the patient. Ultimately, the treatment must be accepted by the patient, who should fully understand the benefits and risks. Boceprevir trials were designed with the concept of individualized and response-guided therapy which establishes treatment decisions on how rapidly patients respond to treatment. Individualized therapy for chronic hepatitis C is based on patient and viral characteristics to make the best choice about whether a person will benefit from therapy and to evaluate on-treatment predictors of response to shorten therapy in patients with a rapid response as well as in patients who did not respond sufficiently to expect HCV eradication. This review focuses on the main results obtained so far, their impact on the treatment of patients with chronic hepatitis C, and potential therapeutic perspectives.

Risk score based PEG Interferon alpha 2b and Ribavirin treatment response estimation model for genotype 1 chronic hepatitis C patients

PURPOSE

Attempt to create simple practical algorithm for prospective assessment of PEG interferon/ribavirin related treatment response in individuals with chronic hepatitis C (CHC) basing on the risk factors defined prior to the treatment initiation.

MATERIAL/METHODS

Retrospective assessment of 45 female and 39 male previously untreated CHC patients aged 20 to 73 years, with genotype 1, undergoing standard treatment with PEG-IFNa2b+RBV was performed. For the final analysis 78 patients were included (38 effectively treated and 40 treatment failures). Thirty-six sustained virological response (SVR) related factors, which were routinely measured before treatment initiation were compared (including physical, biochemical, serologic and histopathologic). From this group the risk factors of the highest predictive value for treatment failure were selected. Cut-off values for statistical significance were defined for each parameter, with risk score (RS) calculated and compared in the group with and without SVR.

RESULTS

Seven factors related to treatment failure were identified: HCV>600000 IU/L, blood platelet count <150000/ul, GGTP>45 IU/ml, total serum protein<7.8 g/dl, glycaemia>105 mg/dl, detectable HBc IgG antibodies and cirrhosis. In the group with RS 1 the likelihood of SVR was 70% (p<0.028), while in patients with RS 3 the response was reduced to 23.8% (p<0.016), with no SVR achieved among patients with RS >3.

CONCLUSIONS

Low risk score (0-2) is associated with high probability of treatment success with scores >3 predictive for treatment failure. The presented model is a simple tool for prediction of treatment success for clinical use before PegIFN/RBV treatment initiation among genotype 1 CHC patients.

Comparison of current US risk strategy to screen for hepatitis C virus with a hypothetical targeted birth cohort strategy

OBJECTIVES

We compared the theoretical performance of a 1-time, birth cohort strategy with the currently recommended risk strategy for screening for hepatitis C virus (HCV) infection, which is undetected in an estimated 75% of 4 million affected people in the United States.

METHODS

We applied current American Association for the Study of Liver Disease risk screening guidelines and a targeted birth cohort strategy to National Health and Nutrition Examination Survey data from 2003 to 2006 to estimate their performance in identifying HCV cases.

RESULTS

Risk guidelines would recommend testing 25% of the US population aged 20 years or older and, if fully implemented, identify 82% of the projected HCV-exposed population. A targeted birth cohort (1946-1964) strategy would test 45% of the same population and identify 76% of the projected HCV population.

CONCLUSIONS

In this ideal-world simulation, birth year and risk screening had similar theoretical performances for predicting HCV infection. However, actual implementation of risk screening has not achieved its theoretical performance, and birth cohort screening might increase HCV testing rates.

Multiple effects of Honokiol on the life cycle of hepatitis C virus

BACKGROUND

Honokiol, a small active molecular compound extracted from magnolia, has recently been shown to inhibit hepatitis C virus (HCV) infection in vitro.

AIMS

This study further characterized aspects of the HCV lifecycle affected by the antiviral functions of honokiol.

METHODS

The influence of honokiol on HCV infection, entry, translation and replication was assessed in Huh-7.5.1 cells using cell culture-derived HCV (HCVcc), HCV pseudo-type (HCVpp) and sub-genomic replicons.

RESULTS

Honokiol had strong antiviral effect against HCVcc infection at non-toxic concentrations. Combined with interferon-α, its inhibitory effect on HCVcc was more profound than that of ribavirin. Honokiol inhibited the cell entry of lentiviral particles pseudo-typed with glycoproteins from HCV genotypes 1a, 1b, and 2a, but not of the vesicular stomatitis virus. It had inefficient activity on HCV internal ribosome entry site (IRES)-translation at concentrations with significant anti-HCVcc effects. The expression levels of components of replication complex, NS3, NS5A and NS5B, were down-regulated by honokiol in a dose-dependent manner. It also inhibited HCV replication dose dependently in both genotypes 1b and 2a sub-genomic replicons.

CONCLUSIONS

Honokiol inhibits HCV infection by targeting cell entry and replication and, only at a concentration >30 μM, IRES-mediated translation of HCV life cycle. Based on its high therapeutic index (LD(50) /EC(90)  = 5.4), honokiol may be a promising drug for the treatment of HCV infection.

Anti-hepatitis C virus activity of 3-hydroxy caruilignan C from Swietenia macrophylla stems

Chronic hepatitis C virus (HCV) infection ultimately leads to chronic hepatitis, hepatic cirrhosis and hepatocellular carcinoma (HCC). As the standard treatment is not completely efficacious, a safer and more effective agent against HCV infection needs to be developed. In this report, we demonstrated that 3-hydroxy caruilignan C (3-HCL-C) isolated from Swietenia macrophylla stems exhibited high anti-HCV activity at both protein and RNA levels at nontoxic concentrations, with an EC(50) value of 10.5 ± 1.2 μm. Combinations of 3-HCL-C and interferon-α (IFN-α), an HCV NS5B polymerase inhibitor (2'-C-methylcytidine; NM-107) or an HCV NS3/4A protease inhibitor (Telaprevir; VX-950) increased the suppression of HCV RNA replication. The results suggested that 3-HCL-C may be a potential anti-viral agent. We then demonstrated that 3-HCL-C interfered with HCV replication by inducing IFN-stimulated response element transcription and IFN-dependent anti-viral gene expression.

The cyclophilin inhibitor alisporivir prevents hepatitis C virus-mediated mitochondrial dysfunction

Alisporivir (Debio-025) is an analogue of cyclosporine A and represents the prototype of a new class of non-immunosuppressive cyclophilin inhibitors. In vitro and in vivo studies have shown that alisporivir inhibits hepatitis C virus (HCV) replication, and ongoing clinical trials are exploring its therapeutic potential in patients with chronic hepatitis C. Recent data suggest that the antiviral effect is mediated by inhibition of cyclophilin A, which is an essential host factor in the HCV life cycle. However, alisporivir also inhibits mitochondrial permeability transition by binding to cyclophilin D. Because HCV is known to affect mitochondrial function, we explored the effect of alisporivir on HCV protein-mediated mitochondrial dysfunction. Through the use of inducible cell lines, which allow to investigate the effects of HCV polyprotein expression independent from viral RNA replication and which recapitulate the major alterations of mitochondrial bioenergetics observed in infectious cell systems, we show that alisporivir prevents HCV protein-mediated decrease of cell respiration, collapse of mitochondrial membrane potential, overproduction of reactive oxygen species and mitochondrial calcium overload. Strikingly, some of the HCV-mediated mitochondrial dysfunctions could even be rescued by alisporivir.

CONCLUSION

These observations provide new insights into the pathogenesis of HCV-related liver disease and reveal an additional mechanism of action of alisporivir that is likely beneficial in the treatment of chronic hepatitis C.

New developments in small molecular compounds for anti-hepatitis C virus (HCV) therapy

Infection with hepatitis C virus (HCV) affects approximately 170 million people worldwide. However, no vaccine or immunoglobulin is currently available for the prevention of HCV infection. The standard of care (SOC) involving pegylated interferon-α (PEG-IFN α) plus ribavirin (RBV) for 48 weeks results in a sustained virologic response in less than 50% of patients with chronic hepatitis C genotype 1, the most prevalent type of HCV in North America and Europe. Recently, reliable in vitro culture systems have been developed for accelerating antiviral therapy research, and many new specifically targeted antiviral therapies for hepatitis C (STAT-C) and treatment strategies are being evaluated in clinical trials. These new antiviral agents are expected to improve present treatment significantly and may potentially shorten treatment duration. The aim of this review is to summarize the current developments in new anti-HCV drugs.

Hepatitis C virus-host interactions: Etiopathogenesis and therapeutic strategies

Hepatitis C virus (HCV) is a significant health problem facing the world. This virus infects more than 170 million people worldwide and is considered the major cause of both acute and chronic hepatitis. Persons become infected mainly through parenteral exposure to infected material by blood transfusions or injections with nonsterile needles. Although the sexual behavior is considered as a high risk factor for HCV infection, the transmission of HCV infection through sexual means, is less frequently. Currently, the available treatment for patients with chronic HCV infection is interferon based therapies alone or in combination with ribavirin and protease inhibitors. Although a sustained virological response of patients to the applied therapy, a great portion of patients did not show any response. HCV infection is mostly associated with progressive liver diseases including fibrosis, cirrhosis and hepatocellular carcinoma. Although the focus of many patients and clinicians is sometimes limited to that problem, the natural history of HCV infection (HCV) is also associated with the development of several extrahepatic manifestations including dermatologic, rheumatologic, neurologic, and nephrologic complications, diabetes, arterial hypertension, autoantibodies and cryglobulins. Despite the notion that HCV-mediated extrahepatic manifestations are credible, the mechanism of their modulation is not fully described in detail. Therefore, the understanding of the molecular mechanisms of HCV-induced alteration of intracellular signal transduction pathways, during the course of HCV infection, may offer novel therapeutic targets for HCV-associated both hepatic and extrahepatic manifestations. This review will elaborate the etiopathogenesis of HCV-host interactions and summarize the current knowledge of HCV-associated diseases and their possible therapeutic strategies.

Japanese reference panel of blood specimens for evaluation of hepatitis C virus RNA and core antigen quantitative assays

An accurate and reliable quantitative assay for hepatitis C virus (HCV) is essential for measuring viral propagation and the efficacy of antiviral therapy. There is a growing need for domestic reference panels for evaluation of clinical assay kits because the performance of these kits may vary with region-specific genotypes or polymorphisms. In this study, we established a reference panel by selecting 80 donated blood specimens in Japan that tested positive for HCV. Using this panel, we quantified HCV viral loads using two HCV RNA kits and five core antigen (Ag) kits currently available in Japan. The data from the two HCV RNA assay kits showed excellent correlation. All RNA titers were distributed evenly across a range from 3 to 7 log IU/ml. Although the data from the five core Ag kits also correlated with RNA titers, the sensitivities of individual kits were not sufficient to quantify viral load in all samples. As calculated by the correlation with RNA titers, the theoretical lower limits of detection by these core Ag assays were higher than those for the detection of RNA. Moreover, in several samples in our panel, core Ag levels were underestimated compared to RNA titers. Sequence analysis in the HCV core region suggested that polymorphisms at amino acids 47 to 49 of the core Ag were responsible for this underestimation. The panel established in this study will be useful for estimating the quality of currently available and upcoming HCV assay kits; such quality control is essential for clinical usage of these kits.

Discovery and development of telaprevir: an NS3-4A protease inhibitor for treating genotype 1 chronic hepatitis C virus

Infection with hepatitis C virus (HCV) is a major medical problem with over 170 million people infected worldwide. Substantial morbidity and mortality are associated with hepatic manifestations (cirrhosis and hepatocellular carcinoma), which develop with increasing frequency in people infected with HCV for more than 20 years. Less well known is the burden of HCV disease associated with extrahepatic manifestations (diabetes, B-cell proliferative disorders, depression, cognitive disorders, arthritis and Sjögren's syndrome). For patients infected with genotype 1 HCV, treatment with polyethylene glycol decorated interferon (peginterferon) α and ribavirin (PR) is associated with a low (40-50%) success rate, substantial treatment-limiting side effects and a long (48-week) duration of treatment. In the past 15 years, major scientific advances have enabled the development of new classes of HCV therapy, the direct-acting antiviral agents, also known as specifically targeted antiviral therapy for hepatitis C (STAT-C). In combination with PR, the HCV NS3-4A protease inhibitor telaprevir has recently been approved for treatment of genotype 1 chronic HCV in the United States, Canada, European Union and Japan. Compared with PR, telaprevir combination therapy offers significantly improved viral cure rates and the possibility of shortened treatment duration for diverse patient populations. Developers of innovative drugs have to blaze a new path with few validated sign posts to guide the way. Indeed, telaprevir's development was once put on hold because of its performance in a standard IC(50) assay. Data from new hypotheses and novel experiments were required to justify further investment and reduce risk that the drug might fail in the clinic. In addition, the poor drug-like properties of telaprevir were a formidable hurdle, which the manufacturing and formulation teams had to overcome to make the drug. Finally, novel clinical trial designs were developed to improve efficacy and shorten treatment in parallel instead of sequentially. Lessons learned from the development of telaprevir suggest that makers of innovative medicines cannot rely solely on traditional drug discovery metrics, but must develop innovative, scientifically guided pathways for success.

An integrated transcriptomic and meta-analysis of hepatoma cells reveals factors that influence susceptibility to HCV infection

Hepatitis C virus (HCV) is a global problem. To better understand HCV infection researchers employ in vitro HCV cell-culture (HCVcc) systems that use Huh-7 derived hepatoma cells that are particularly permissive to HCV infection. A variety of hyper-permissive cells have been subcloned for this purpose. In addition, subclones of Huh-7 which have evolved resistance to HCV are available. However, the mechanisms of susceptibility or resistance to infection among these cells have not been fully determined. In order to elucidate mechanisms by which hepatoma cells are susceptible or resistant to HCV infection we performed genome-wide expression analyses of six Huh-7 derived cell cultures that have different levels of permissiveness to infection. A great number of genes, representing a wide spectrum of functions are differentially expressed between cells. To focus our investigation, we identify host proteins from HCV replicase complexes, perform gene expression analysis of three HCV infected cells and conduct a detailed analysis of differentially expressed host factors by integrating a variety of data sources. Our results demonstrate that changes relating to susceptibility to HCV infection in hepatoma cells are linked to the innate immune response, secreted signal peptides and host factors that have a role in virus entry and replication. This work identifies both known and novel host factors that may influence HCV infection. Our findings build upon current knowledge of the complex interplay between HCV and the host cell, which could aid development of new antiviral strategies.

Lipoprotein lipase inhibits hepatitis C virus (HCV) infection by blocking virus cell entry

A distinctive feature of HCV is that its life cycle depends on lipoprotein metabolism. Viral morphogenesis and secretion follow the very low-density lipoprotein (VLDL) biogenesis pathway and, consequently, infectious HCV in the serum is associated with triglyceride-rich lipoproteins (TRL). Lipoprotein lipase (LPL) hydrolyzes TRL within chylomicrons and VLDL but, independently of its catalytic activity, it has a bridging activity, mediating the hepatic uptake of chylomicrons and VLDL remnants. We previously showed that exogenously added LPL increases HCV binding to hepatoma cells by acting as a bridge between virus-associated lipoproteins and cell surface heparan sulfate, while simultaneously decreasing infection levels. We show here that LPL efficiently inhibits cell infection with two HCV strains produced in hepatoma cells or in primary human hepatocytes transplanted into uPA-SCID mice with fully functional human ApoB-lipoprotein profiles. Viruses produced in vitro or in vivo were separated on iodixanol gradients into low and higher density populations, and the infection of Huh 7.5 cells by both virus populations was inhibited by LPL. The effect of LPL depended on its enzymatic activity. However, the lipase inhibitor tetrahydrolipstatin restored only a minor part of HCV infectivity, suggesting an important role of the LPL bridging function in the inhibition of infection. We followed HCV cell entry by immunoelectron microscopy with anti-envelope and anti-core antibodies. These analyses demonstrated the internalization of virus particles into hepatoma cells and their presence in intracellular vesicles and associated with lipid droplets. In the presence of LPL, HCV was retained at the cell surface. We conclude that LPL efficiently inhibits HCV infection by acting on TRL associated with HCV particles through mechanisms involving its lipolytic function, but mostly its bridging function. These mechanisms lead to immobilization of the virus at the cell surface. HCV-associated lipoproteins may therefore be a promising target for the development of new therapeutic approaches.

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.

Ceestatin, a novel small molecule inhibitor of hepatitis C virus replication, inhibits 3-hydroxy-3-methylglutaryl-coenzyme A synthase

BACKGROUND

Hepatitis C virus (HCV) chronically infects >170 million persons worldwide and is a leading cause of cirrhosis and hepatocellular carcinoma. The identification of more effective and better-tolerated agents for treating HCV is a high priority. We have reported elsewhere the discovery of the anti-HCV compound ceestatin using a high-throughput screen of a small molecule library.

METHODS

To identify host or viral protein targets in an unbiased fashion, we performed affinity chromatography, using tandem liquid chromatography/mass spectrometry to identify specific potential targets. RESULTS. Ceestatin binds to 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) synthase and irreversibly inhibits HMG-CoA synthase in a dose-dependent manner. Ceestatin's anti-HCV effects are reversed by addition of HMG-CoA, mevalonic acid, or geranylgeraniol. Treatment with small interfering RNA against HMG-CoA synthase led to a substantial reduction in HCV replication, further validating HMG-CoA synthase as an enzyme essential for HCV replication.

CONCLUSIONS

Ceestatin therefore exerts its anti-HCV effects through inhibition of HMG-CoA synthase. It may prove useful as an antiviral agent, as a probe to study HCV replication, and as a cholesterol-lowering agent. The logical stepwise process employed to discover the mechanism of action of ceestatin can serve as a general experimental strategy to uncover the targets on which novel uncharacterized anti-HCV compounds act.

Treatment of severe acute hepatitis E by ribavirin

BACKGROUND

Acute hepatitis E is associated with a higher rate of mortality as compared to hepatitis A or B infections in some series. To date no treatment has been recommended for acute hepatitis E. However, ribavirin has been recently reported to be highly effective to treat solid-organ-transplant recipients chronically infected with hepatitis E virus (HEV).

OBJECTIVE AND STUDY DESIGN

We report here on the use of ribavirin to treat severe acute HEV infection in a non-immunocompromized patient. This 61-year-old-man presented with acute hepatitis with HEV genotype 3. Seven days after admission, prothrombin index was 38%, bilirubinaemia was 550 μmol/L and alanine aminotransferases level was still increasing, reaching 4565IU/L. No hepatic encephalopathy was noted. Ribavirin (1200 mg/day) was introduced.

RESULTS

Liver biological tests showed rapid improvement concurrently with a decrease in HEV RNA levels in serum samples. Therapy was interrupted after 21 days. At that time, ALT had normalized, bilirubinemia was 138 μmol/L, and HEV RNA was almost undetectable in the serum.

CONCLUSION

Ribavirin therapy could be an effective treatment of severe acute hepatitis E.

Prevalence and clinical significance of GB virus type C/hepatitis G virus coinfection in patients with chronic hepatitis C undergoing antiviral therapy

Coinfection with GBV-C/HGV in patients with chronic hepatitis C (CHC) may influence clinical course and response rates of antiviral therapy. Aim of the study was to investigate the prevalence of GBV-C/HGV/HCV coinfection and its influence on outcome of interferon/ribavirin combination therapy. Three hundred and four patients with CHC [m/f = 211/93, age: 42 (18-65)] were investigated. HGV RNA detection was performed by polymerase chain reaction prior to and 6 months after the end of antiviral therapy. HGV/HCV coinfection could be identified in 37/304 (12.2%) patients with intravenous drug abuse as the most common source of infection (N = 21, (56.8%)). The predominant HCV genotype in coinfected individuals was HCV-3a (HCV-3a: 51.4%, HCV-1: 37.8%, HCV-4: 10.8%). HGV coinfection was more prevalent in patients infected with HCV-3 compared to HCV-1 or HCV-4 [19/45 (42.2%) vs. 14/185 (7.6%) vs. 4/52 (7.7%), P < 0.01]. Patients with HGV/HCV coinfection were younger [35 (18-56) vs. 43 (19-65), years; P < 0.01], and advanced fibrosis (F3-F4) was less frequent (22.2% vs. 42.9%, P < 0.05). A sustained virological response was achieved more frequently in HGV/HCV coinfected patients [26/37 (70.3%)] than in monoinfected patients [120/267 (44.9%), P < 0.01]. HGV RNA was undetectable in 65.7% of the coinfected patients at the end of follow-up. Intravenous drug abuse seems to be a major risk factor for HGV coinfection in patients with chronic hepatitis C. Coinfection with HGV does not worsen the clinical course of chronic hepatitis C or diminish response of HCV to antiviral therapy. Interferon/ribavirin combination therapy also clears HGV infection in a high proportion of cases.