Therapeutic modalities in hepatitis C: challenges and development

Redox cell signaling and hepatic progenitor cells

Hepatic diseases are widespread in the world and organ transplantation is currently the only treatment for liver failure. New cell-based approaches have been considered, since stem cells may represent a possible source to treat liver diseases. Acute and chronic liver diseases are characterized by high production of reactive oxygen and nitrogen species, with consequent oxidative modifications of cellular macromolecules and alteration of signaling pathways, metabolism and cell cycle. Although considered harmful molecules, reactive species are involved in cell growth and differentiation processes, modulating the activity of transcription factors, which take part in stemness/proliferation. It is conceivable that redox balance may regulate the development of hepatic progenitor cells, function and survival in synchrony with metabolism during chronic liver diseases. This review aims to summarize diverse redox-sensitive signaling pathways involved in stem cell fate, highlighting the important role of hepatic progenitor cells as a possible source to treat end-stage liver disease for organ regeneration.

Type I interferons in viral control and immune regulation

•

IFN-I signaling has recently been shown to contribute to viral immune pathologies.

•

Elevated IFN-I signatures are found in persistent virus infections in multiple species.

•

Blocking IFN-I signaling reduces immune system activation, regulatory molecule expression.

•

Inhibiting IFN-I signaling promotes hastened control of persistent LCMV infection.

•

Targeting IFN-I signaling during viral infection may treat a range of viral diseases.

Type 1 interferons (IFN-I) exert pleiotropic biological effects during viral infections, all which contribute to balancing virus control and immune pathology. Despite extensive antiviral functions that subdue virus replication, recent studies demonstrate pathogenic and pro-viral roles for IFN-I signaling during acute and persistent virus infection. IFN-I signaling can promote morbidity and mortality through induction of aberrant inflammatory responses during acute viral infection. In contrast, IFN-I signaling during persistent viral infection supports immune suppression, lymphoid tissue disorganization and CD4 T cell dysfunction. Systematic characterization of the cellular populations and intricacies of IFN-I signaling that promote pathology or immune suppression during acute and persistent viral infections, respectively, should inform the development of treatments and modalities to control viral associated pathologies.

Pleiotropic Roles of Type 1 Interferons in Antiviral Immune Responses

Since Isaac's and Lindenmann's seminal experiments over 50 years ago demonstrating a soluble factor generated from heat killed virus-stimulated chicken embryos could inhibit live influenza virus replication, the term interferon has been synonymous with inhibition of virus replication. While the antiviral properties of type 1 interferon (IFN-I) are undeniable, recent studies have reported expanding and somewhat unexpected roles of IFN-I signaling during both acute and persistent viral infections. IFN-I signaling can promote morbidity and mortality through induction of aberrant inflammatory responses and recruitment of inflammatory innate immune cell populations during acute respiratory viral infections. During persistent viral infection, IFN-I signaling promotes containment of early viral replication/dissemination, however, also initiates and maintains immune suppression, lymphoid tissue disorganization, and CD4 T cell dysfunction through modulation of multiple immune cell populations. Finally, new data are emerging illuminating how specific IFN-I species regulate immune pathology and suppression during acute and persistent viral infections, respectively. Systematic characterization of the cellular populations that produce IFN-I, how the timing of IFN-I induction and intricacies of subtype specific IFN-I signaling promote pathology or immune suppression during acute and persistent viral infections should inform the development of treatments and modalities to control viral associated pathologies.

Dual inhibition of HCV and HIV by ring-expanded nucleosides containing the 5:7-fused imidazo[4,5-e][1,3]diazepine ring system. In vitro results and implications

Examples of ring-expanded nucleosides (RENs), represented by general structures 1 and 2, exhibited dual anti-HCV and anti-HIV activities in both cell culture systems and the respective target enzyme assays, including HCV NTPase/helicase and human RNA helicase DDX3. Since HCV is a leading co-infection in late stage HIV AIDS patients, often leading to liver cirrhosis and death, the observed dual inhibition of HCV and HIV by the target nucleoside analogues has potentially beneficial implications in treating HIV patients infected with HCV.

Thyroid disease in chronic hepatitis C infection treated with combination interferon-α and ribavirin: management strategies and future perspective

OBJECTIVE

Hepatitis C virus (HCV) infection is one of the major epidemics afflicting young people in both developed and developing countries. The most common endocrine disorder associated with this infection, especially in conjunction with interferon-α (IFN-α)-based therapy, is thyroid disease (TD). This review examines the development of TD before, during, and after the completion of treatment with combination IFN-α and ribavirin (RBV) for chronic HCV infection. We also summarize the current understanding of the natural history of the condition and propose management and follow-up guidelines.

METHODS

PubMed was searched up to June 30, 2011 for English-language publications that contained the search terms "hepatitis C virus," "chronic hepatitis C," "HCV," "thyroid disease," "thyroiditis," "autoimmunity," "interferon-alpha," and "ribavirin." Additional publications were identified from the reference lists of identified papers. The included studies were original research publications and included combination IFN-α and RBV use in patients that developed TD.

RESULTS

The prevalence of TD before combination IFN-α and RBV therapy ranges from 4.6 to 21.3%; during therapy, 1.1 to 21.3%; and after therapy, 6.7 to 21.3%. The most common TD is thyroiditis. Thyroid function testing (TFT) frequency and diagnostic criteria for various thyroid conditions are not standardized, and many of the existing studies are retrospective.

CONCLUSION

Patients undergoing this therapy should be assessed with a standardized protocol to appropriately detect and manage developed TD. Based on the currently available literature, we recommend that patients receiving combination interferon-α and RBV therapy undergo monthly thyrotropin (TSH) level testing.

Gene expression patterns in livers of Hispanic patients infected with hepatitis C virus

We report a gene expression study aimed at the identification of genes differentially expressed in the livers of Hispanic patients infected with hepatitis C virus (HCV). Six uninfected controls were compared with 14 HCV(+) patients in which the liver biopsies were obtained at the time of diagnosis. Among the latter, five patients were also analyzed 4 weeks after the onset of standard anti-HCV therapy (pegylated interferon-α + ribavirin). We identified many genes up- or down-regulated by the infection with HCV in the human livers. When these genes were subjected to pathway analysis, several prominent pathways were revealed including many interferon (IFN)-inducible pathways as well as immune cell trafficking, inflammation, anti-microbial responses, and even cancer. We detected expression of many genes that have previously been associated with HCV infection, as well as several novel genes including CD47. The genes induced by HCV infection showed large expression changes, whereas the genes induced by the IFN-α combination therapy were relatively few (including MX2, ORMDL3, GPAM, KOPX18, TMEM56, and HBP1) and they reflected relatively small expression changes. This is the first study to identify changes in gene expression in livers of HCV(+) Hispanic patients and the first to identify genes induced by anti-HCV combination therapy in the human liver.

Quasispecies of genotype 4 of hepatitis C virus genomes in Saudi patients managed with interferon alfa and ribavirin therapy

BACKGROUND AND OBJECTIVES

Many patients with hepatitis C virus (HCV) infection do not respond to antiviral treatment, possibly due to viral quasispecies. We aimed to investigate whether the quasispecies population could be used as a predictor of response to therapy in our patients.

METHODS

The quasispecies of HCV genotype 4 (HCV-4) were studied in 25 naïve Saudi patients at zero, three, and six months following interferon alfa and ribavirin combination therapy. Hypervariable region 1 within the E2/NS1 gene of the virus was analyzed by the single-strand conformation polymorphism (SSCP) technique after amplification.

RESULTS

Pretreatment DNA bands by SSCP (2-7 bands) were detected in all patients. In those who achieved a complete virological response within six months (viral load P=.53). Two of the four patients with pretreatment high viral load and the same or decreased composition of quasispecies bands responded to the therapy.

CONCLUSION

Quasispecies in our studied patients cannot be used to predict responsiveness to treatment, but may offer an explanation for failure of most HCV-4 patients to respond to interferon alfa and ribavirin therapy.

In vivo study of HCV in mice with chimeric human livers

Estimates of hepatitis C virus infection include 170 million people worldwide, who face increased risk of development of cirrhosis, liver failure, and hepatocellular carcinoma. Standard of care therapy with pegylated interferon and ribavirin is effective in just half of patients, is challenged by substantial treatment-related morbidity, and is prohibitively expensive in most parts of the world. New therapeutics for treatment and prevention are clearly needed. Development of effective therapies has been significantly hampered by difficulties in establishing in vitro and in vivo models of viral replication. This chapter reviews development, validation, and early application of a mouse model with a chimeric human liver.

Interferon-beta treatment for relapsing multiple sclerosis

BACKGROUND

Recombinant forms of IFN-beta were the first therapeutic intervention found to be effective at interfering with the course of multiple sclerosis (MS), a chronic and debilitating disease affecting the CNS in young adults.

OBJECTIVE/METHODS

To examine the application of IFN-beta to MS treatment by a review of relevant literature.

RESULTS

The different IFN-beta products available are similar in their clinical effects. However, the response to IFN-beta therapy is only partial and the most efficient individual-specific dose, route and frequency of administration are not elucidated fully. The mechanism of action of IFN-beta in MS is also not understood fully but its immunomodulatory effects are probably more important than its anti-proliferative and antiviral activities.

CONCLUSIONS

Although new therapeutic approaches are being sought to better treat MS, IFN-beta remains one of the most recognized and approved worldwide therapeutic options for this disease.

Predictive graphical model, network-based medical tool for the prognosis of chronic hepatitis C patients treated with peg-interferon plus ribavirin

BACKGROUND

There are few model networks to predict treatment outcome in viral hepatitis.

AIM

To develop an easy bioinformatics platform based on algorithm decisions (Bayesian network) for a more efficient prediction of treatment response.

METHODS

Totally 385 consecutive chronic hepatitis C (CHC) treated patients were included. More than 40 variables were analysed. Data from 308 patients were used to build the variable model network using DLIFE platform based on predictive graphical models. The prediction accuracy of the bioinformatics network was compared with the true data collected in a retrospective study. The model was then validated twice with external data from CHC patients treated in other hospitals.

RESULTS

The accuracy of this bioinformatics network for treatment response in our 308 patients was 83.3%, which is higher than the accuracy obtained by physicians on the basis of study of clinical data and their own experience (50-65%). The receiver operator characteristic curve areas after validation with another cohort of patients were: 0.91 for sustained virological response, one for nonresponse, and 0.81 for relapse. DLIFE offered a diagnostic accuracy of 81.3%, which is a clear improvement compared with unassisted prognosis (50-65%).

CONCLUSIONS

This bioinformatics platform (DLIFE) accurately predicts the outcome of CHC combination therapy, improving treatment decisions and reducing costs. This bioinformatics platform allows integrating widespread data sources and permits predicting the clinical outcome of a particular patient using a general predictive graphical model.

Second hepatic resection for recurrent hepatocellular carcinoma in patients with chronic hepatitis C

BACKGROUND

Although a second hepatic resection (SHR) for recurrent hepatocellular carcinoma (HCC) is widely accepted, the indications for SHR have not been established. The risk factors for HCC recurrence after SHR were evaluated to investigate the indications for SHR.

METHODS

Subjects included 51 patients who underwent a second hepatic resection for recurrence of HCV-related HCC. Sixteen patients received interferon therapy before or after the first operation. Six patients attained a sustained viral response (SVR) that was defined as return of the alanine aminotransferase (ALT) activity to within the reference range and no detectable serum HCV RNA for at least 1 year after interferon therapy. A biochemical response (BR), defined as a normalized ALT activity for at least 1 year after interferon therapy with or without the transient disappearance of serum HCV RNA, was attained in three patients. The other seven patients were defined as the nonresponse (NR) group.

RESULTS

By univariate analysis, NR and lack of interferon therapy, high indocyanine green retention rate at 15 min (ICGR15), high aspartate aminotransferase activity, high ALT activity, large tumor, and multiple tumors were risk factors for HCC recurrence after SHR. By multivariate analysis, NR and lack of interferon therapy, high ICGR15, large tumor, and multiple tumors were independent risk factors.

CONCLUSIONS

Patients in whom active hepatitis has been controlled by interferon therapy are the best candidates for SHR. Interferon therapy should be recommended in patients undergoing resection of an HCV-related HCC because SHR can prolong life in SVR and BR patients.

Desperately seeking hepatitis C virus

Spanish investigators described recently the so-called occult hepatitis C virus (HCV) infection, emphasizing the detection of genomic and antigenomic HCV RNA strands in liver and peripheral blood mononuclear cells. Therefore, the persistence of viral replication in occult HCV infection should be considered as a putative source of infection among family members and patients undergoing invasive procedures, transfusion or transplantation. Additionally, the most worrisome finding is that an occult HCV infection may persist in patients with sustained virological response.

Vasculite cutânea crioglobulinêmica induzida por infecção crônica pelo vírus da hepatite C

As vasculites cutâneas podem representar grande desafio clínico, mesmo após exame dermatológico cuidadoso e realização de exames complementares. Os autores apresentam caso de vasculite crioglobulinêmica cutânea associada à infecção crônica pelo vírus da hepatite C, salientando a importância do exame dermatológico na investigação diagnóstica. Discutem ainda a importância da busca da etiologia e da correta classificação no prognóstico e terapêutica das vasculites cutâneas.

[Treatment options for chronic hepatitis C virus infection]

INTRODUCTION

The incidence of chronic hepatitis C virus (HCV) infection is rather high. Its most frequent consequences are chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma.

TREATMENT OF CHRONIC HCV INFECTION

In treatment of chronic HCV infection, interferons have antiviral, anriproliferative, and immunoregulatory action. Within the cell, they induce protein synthesis, inhibiting viral replication. The most important among them are RNA dependent protein kinase, and eukaryotic initiation factor. However, viral proteins prevent their phosphorylation and activation. In order to overcome this problem, treatment is prolonged, higher doses of lFN are used, as well as induction therapy. The optimal period for viral response is 52 weeks, while induction therapy has shown controversial results.

Evaluation of a pharmacist-managed hepatitis C care clinic

PURPOSE

A description of an effort to create a more time, labor, and cost-efficient method for the management of patients with hepatitis C virus (HCV) infection in Department of Veterans Affairs (VA) hospitals is provided; this pilot study also revealed the outcomes of a pharmacist-managed clinic for these patients in comparison to established standards of care.

METHODS

A retrospective analysis was performed on data obtained from patients who were referred to the clinic between October 2002 and March 2004 and who had a clinical pharmacist as their primary treatment provider. The patients' medical records were searched for demographic information, disease characteristics, treatment information, treatment and safety information, and virological response.

RESULTS

Thirty-one patients were evaluated, and 27 were offered antiviral therapy in the hepatitis C care clinic between October 2002 and March 2004. Of the 27 patients who had sufficient data for analysis, there was a sustained response rate of 63% (17 of 27) overall after treatment with peginterferon and ribavirin combination therapy. Only 3 patients (11%) stopped therapy early secondary to adverse effects, whereas 8 (30%) were managed with growth factors.

CONCLUSION

VA patients managed by a clinical pharmacist for the treatment of chronic HCV infection demonstrated similar treatment outcomes compared with the results from earlier studies with VA patients managed with traditional care. Further studies are warranted to investigate the role of the pharmacist in the management of patients with HCV infection.

Pegylated interferon-alpha2beta in combination with ribavirin does not aggravate thyroid dysfunction in comparison to regular interferon-alpha2beta in a hepatitis C population: meta-analysis

BACKGROUND

Interferon (IFN) has been well documented to cause thyroid dysfunction, especially in high risk patients and when combined with ribavirin (RBV). There is very sparse data to assess if pegylated IFN will further aggravate the thyroid disease risk in comparison to regular IFN. The purpose of this study was to assess the risk of developing thyroid disease with pegylated IFN (pIFN) versus regular IFN (rIFN) therapy (in combination with RBV). We also pooled our results with previous studies in a meta-analysis.

METHODS

An observational study was made retrospectively of 24 patients who underwent a combination of rIFN and RBV therapy for hepatitis C virus (HCV) infection. As these patients failed to obtain an initial satisfactory response, they were retreated using pIFN and RBV. Monthly thyrotropin (TSH) levels were assessed while undergoing both treatment regimens. A meta-analysis was performed using available published data in PubMed.

RESULTS

No difference in TSH levels was observed when comparing rIFN/RBV with pIFN/RBV. None of the patients developed hypo- or hyperthyroidism. TSH levels fluctuated during the treatment but did not extend outside the reference range. No further investigation was carried out in the absence of clinical and biochemical thyroid disease. The result of the meta-analysis failed to find any excess risk of thyroid dysfunction using pIFN above that of rIFN.

CONCLUSIONS

The pegylation of IFN, in combination with RBV, did not aggravate thyroid diseases in the hepatitis C population. This finding is reassuring and dictates that no deviation from current practice regarding thyroid surveillance is required whilst undergoing HCV treatment.

Therapeutic role of beta-interferons in multiple sclerosis

Multiple sclerosis (MS) is an inflammatory disease of the central nervous system (CNS). In the last 12 years, there has been a proliferation of studies elucidating the immune mechanisms that mediate tissue damage in MS. Interferons (IFNs) have an important role in regulating innate and adaptive immune responses. They decrease pro-inflammatory responses such as the autoimmunity in MS, but other autoimmune responses such as systemic lupus erythematosus (SLE) may be exacerbated. This review offers a general overview of the biological properties of IFNs, effects on immune cells, and clinical effectiveness in MS treatment. IFN signaling is complex, from receptor binding events to the generation of effector mechanisms that dampen inflammation. Immune cell function is altered in MS. IFN treatment of MS patients ameliorates immune dysfunction, but not completely. The incomplete resolution of immune dysfunction by IFNs partly explains their significant, but modest therapeutic effects. This observation also suggests that there are immune mechanisms in MS that are resistant to IFN therapy. In MS, abnormalities may exist at several points along the IFN signaling pathway, including molecular defects in the IFN second messenger system. Currently, several studies are ongoing evaluating ways of potentiating IFN effects. IFNs were the first agents to show clinical efficacy in treatment of MS. More than a decade of experience with IFNs has showed continued clinical efficacy over time. In the near future, IFNs will continue to play a major role in MS.

Synthesis and in vitro anti-hepatitis B and C virus activities of ring-expanded ('fat') nucleobase analogues containing the imidazo[4,5-e][1,3]diazepine-4,8-dione ring system

As part of our structure-activity relationship studies, we report here the synthesis and in vitro anti-HBV and anti-HCV activities of a number of ring-expanded ('fat') nucleobases containing the imidazo[4,5-e][1,3]diazepine-4,8-dione ring system. One of the compounds, ZP-88, exhibited a good activity/toxicity profile against HBV by inhibition of the synthesis of extracellular virion release (EC(50)=1.7microM, CC(50)=286microM, SI=168) and intracellular HBV replication intermediates (EC(50)=8.4microM, CC(50)=286microM, SI=34) in cultured human hepatoblastoma 2.2.15 cells. By contrast, most of the compounds tested against HCV had only marginal activity/toxicity profile, although that was still better than that of the reference compound ribavirin.