Treatment options in HBV

Engineered zinc-finger transcription factors inhibit the replication and transcription of HBV in vitro and in vivo

In the present study, an artificial zinc-finger transcription factor eukaryotic expression vector specifically recognizing and binding to the hepatitis B virus (HBV) enhancer (Enh) was constructed, which inhibited the replication and expression of HBV DNA. The HBV EnhI‑specific pcDNA3.1‑artificial transcription factor (ATF) vector was successfully constructed, and then transformed or injected into HepG2.2.15 cells and HBV transgenic mice, respectively. The results demonstrated that the HBV EnhI (1,070‑1,234 bp)‑specific ATF significantly inhibited the replication and transcription of HBV DNA in vivo and in vitro. The HBV EnhI‑specific ATF may be a meritorious component of progressive combination therapies for eliminating HBV DNA in infected patients. A radical cure for chronic HBV infection may become feasible by using this bioengineering technology.

[Functional MR imaging of the liver]

The diagnostics of diffuse liver disease traditionally rely on liver biopsies and histopathological analysis of tissue specimens. However, a liver biopsy is invasive and carries some non-negligible risks, especially for patients with decreased liver function and those requiring repeated follow-up examinations. Over the last decades, magnetic resonance imaging (MRI) has developed into a valuable tool for the non-invasive characterization of focal liver lesions and diseases of the bile ducts. Recently, several MRI methods have been developed and clinically evaluated that also allow the diagnostics and staging of diffuse liver diseases, e.g. non-alcoholic fatty liver disease, hepatitis, hepatic fibrosis, liver cirrhosis, hemochromatosis and hemosiderosis. The sequelae of diffuse liver diseases, such as a decreased liver functional reserve or portal hypertension, can also be detected and quantified by modern MRI methods. This article provides the reader with the basic principles of functional MRI of the liver and discusses the importance in a clinical context.

Magnetic resonance elastography of liver: technique, analysis, and clinical applications

Many pathological processes cause marked changes in the mechanical properties of tissue. MR elastography (MRE) is a noninvasive MRI based technique for quantitatively assessing the mechanical properties of tissues in vivo. MRE is performed by using a vibration source to generate low frequency mechanical waves in tissue, imaging the propagating waves using a phase contrast MRI technique, and then processing the wave information to generate quantitative images showing mechanical properties such as tissue stiffness. Since its first description in 1995, published studies have explored many potential clinical applications including brain, thyroid, lung, heart, breast, and skeletal muscle imaging. However, the best-documented application to emerge has been the use of MRE to assess liver disease. Multiple studies have demonstrated that there is a strong correlation between MRE-measured hepatic stiffness and the stage of fibrosis at histology. The emerging literature indicates that MRE can serve as a safer, less expensive, and potentially more accurate alternative to invasive liver biopsy which is currently the gold standard for diagnosis and staging of liver fibrosis. This review describes the basic principles, technique of performing a liver MRE, analysis and calculation of stiffness, clinical applications, limitations, and potential future applications.

Inhibition of hepatitis B Virus replication by hepatocyte nuclear factor 4-alpha specific short hairpin RNA

BACKGROUND

Previous studies showed that hepatocyte nuclear factor 4α (HNF4α) may play a critical role in hepatitis B virus (HBV) replication.

AIMS

This study aimed to investigate the effect of knocking down of HNF4α with RNA interference technique on HBV replication in a HBV replication mouse model.

METHODS

Four HNF4α, specific short hairpin RNA (shRNA)-producing plasmids were constructed. HBV mRNA and DNA replication intermediates were analysed using Northern and Southern blot respectively. The expression of HNF4α and HBV core antigen (HBcAg) was detected using immunohistochemistry technique.

RESULTS

One of the HNF4α shRNAs, HNF4α shRNA1, efficiently inhibited the expression of HNF4α in HepG2 cells and mice liver. HBV RNA transcripts and DNA replication intermediates in HNF4α shRNA1 group were decreased 67.3 and 76%, respectively, in HepG2 cells, and 68.1 and 70.6% in mice liver respectively. The expression level of HBcAg in the liver was also decreased with the inhibition of HNF4α expression.

CONCLUSIONS

These results suggested that decreasing of HNF4α expression was associated with the reduced level of HBV replication in HepG2 cells and mice liver. These data indicated that HNF4α played a critical role in HBV replication in vivo, and HNF4α shRNA could inhibit HBV replication in vivo.

Enterovirus 71 disrupts interferon signaling by reducing the level of interferon receptor 1

The recent outbreak of enterovirus 71 (EV71) infected millions of children and caused over 1,000 deaths. To date, neither an effective vaccine nor antiviral treatment is available for EV71 infection. Interferons (IFNs) have been successfully applied to treat patients with hepatitis B and C viral infections for decades but have failed to treat EV71 infections. Here, we provide the evidence that EV71 antagonizes type I IFN signaling by reducing the level of interferon receptor 1 (IFNAR1). We show that the host cells could sense EV71 infection and stimulate IFN-β production. However, the induction of downstream IFN-stimulated genes is inhibited by EV71. Also, only a slight interferon response and antiviral effects could be detected in cells treated with recombinant type I IFNs after EV71 infection. Further studies reveal that EV71 blocks the IFN-mediated phosphorylation of STAT1, STAT2, Jak1, and Tyk2 by reducing IFNAR1. Finally, we identified the 2A protease encoded by EV71 as an antagonist of IFNs and show that the protease activity is required for reducing IFNAR1 levels. Taken together, our study for the first time uncovers a mechanism used by EV71 to antagonize type I IFN signaling and provides new targets for future antiviral strategies.

Engineering virus-specific T cells that target HBV infected hepatocytes and hepatocellular carcinoma cell lines

BACKGROUND & AIMS

Virus-specific T cells capable of controlling HBV and eliminating hepatocellular carcinoma (HCC) expressing HBV antigens are deleted or dysfunctional in patients with chronic HBV or HBV-related HCC. The goal of this study was to determine if T cell receptor (TCR) gene transfer can reconstitute HBV-specific T cell immunity in lymphocytes of chronic HBV patients and investigate whether HCC cells with natural HBV-DNA integration can be recognized by genetically modified T cells.

METHODS

We used vector-mediated gene transfer to introduce HLA-A2-restricted, HBV-specific TCRs into T cells of chronic HBV as well as HBV-related HCC patients.

RESULTS

The introduced TCRs were expressed on the cell surface, evidenced by Vβ and pentamer staining. TCR transduced T cells produced IFN-γ, TNF-α, IL-2, and lysed HBV infected hepatocyte-like cell lines. Furthermore, HCC cell lines with natural HBV-DNA integration could be recognized by HBV-specific TCR-re-directed T cells.

CONCLUSIONS

TCR re-directed HBV-specific T cells generated from PBMC of chronic HBV and HBV-related HCC patients were multifunctional and capable of recognizing HBV-infected cells and HCC tumor cells expressing viral antigens from naturally integrated HBV DNA. These genetically modified T cells could be used to reconstitute virus-specific T cell immunity in chronic HBV patients and target tumors in HBV-related HCC.

Synthesis of lamivudine stearate and antiviral activity of stearic acid-g-chitosan oligosaccharide polymeric micelles delivery system

To increase lipophilicity of water-soluble antiviral drug, the prodrug of Lamivudine (LA), Lamivudine stearate (LAS) was synthesized via ester linkage between LA and stearic acid. After the esterification, the octanol-water partition coefficient (logP) of LA increased from -0.95 to 1.82. Stearic acid-g-chitosan oligosaccharide (CSO-SA) micelles have demonstrated fast internalization and accumulation ability to tumor cells. Herein, the CSO-SA with 3.79% amino substitution degree (SD) was prepared for loading LAS. The critical micelle concentration (CMC) of CSO-SA was about 0.032mg/ml. The micelles with 1mg/ml CSO-SA concentration had 460.8nm average diameters with a narrow size distribution and 29.7mV surface zeta potential. After LAS was incorporated, the micellar size decreased and the zeta potential increased. The LAS loaded CSO-SA micelles (CSO-SA/LAS) possessed high entrapment efficiency and drug loading. LA release from CSO-SA/LAS showed a pH-dependent behavior. The release rate of LA from CSO-SA/LAS increased significantly as the pH of release medium reduced from 7.4 to 6.2. CSO-SA/LAS presented a low cytotoxicity and high cellular uptake percentage of LAS against HBV transfected tumor cells (HepG2.2.15). In vitro anti-HBV activities of CSO-SA/LAS presented more conspicuous inhibitory effects on antigen expression and DNA replication compared with LA and LAS.

How can we enhance the performance of liver stiffness measurement using FibroScan in diagnosing liver cirrhosis in patients with chronic hepatitis B?

GOAL

This study aimed to enhance the diagnostic accuracy by defining different cutoff liver stiffness measurement (LSM) values according to alanine aminotransferase (ALT) level and combining LSM with noninvasive models in patients with chronic hepatitis B (CHB).

BACKGROUND

Several studies have indicated that ALT influences LSM using FibroScan.

STUDY

The study prospectively enrolled 200 patients (143 men, mean age 45.4 y) between June 2007 and November 2008 who had been diagnosed with CHB and underwent both liver biopsy and LSM on the same day.

RESULTS

The area under the receiver operating characteristic curves (AUROC) of LSM for predicting cirrhosis in patients with ALT < or = upper limit of normal (ULN) was higher than that of all patients or those with ALT >ULN and < or = 2x ULN (AUROC=0.884 vs. 0.849 and 0.867). The cutoff LSM values for > or = F2, > or = F3, and F4 were 6.0, 7.5, and 10.1 kPa, respectively, in patients with ALT < or = ULN, whereas they were 8.9, 11.0, and 15.5 kPa, respectively, in those with ALT >ULN and < or = 2x ULN. The combination of LSM and the age-spleen-platelet ratio index performed the best at predicting cirrhosis, regardless of ALT level (AUROC=0.917 in patients with ALT < or = ULN, 0.909 in those with ALT < or = 2x ULN, and 0.894 in all patients).

CONCLUSIONS

Different cutoff LSM values according to ALT level and combination with age-spleen-platelet ratio index can enhance the performance of LSM in CHB, regardless of ALT level.

Treatment of hepatitis B virus-infected patients: utility of therapeutic recommendations in developing countries

BACKGROUND

The treatment of individuals infected with hepatitis B virus (HBV) is a complex issue in practical settings, despite the explosion of new and effective antiviral agents.

OBJECTIVE

To assess the scope and limitations of ongoing treatment guidelines against HBV from a global perspective.

METHODS

Present therapeutic guidelines against HBV have been discussed with emphasis on their value in developing countries that harbor about 90% of the total number of global patients who are infected with HBV.

RESULTS/CONCLUSION

Treatment of HBV-infected patients should be appropriately followed up and healthcare delivery systems should be able to combat treatment-induced adverse side effects. Current therapeutic guidelines should be optimized based on the socio-economic conditions of developing countries.

Usefulness of FibroScan for detection of early compensated liver cirrhosis in chronic hepatitis B

BACKGROUND

It is difficult to differentiate early compensated cirrhosis from chronic hepatitis solely by clinical features. The aim of this study was to assess the usefulness of liver stiffness measurement (LSM) for detection of early compensated liver cirrhosis in chronic hepatitis B (CHB).

METHODS

Ninety-one consecutive CHB patients who underwent liver biopsy (LB) and LSM were recruited. All patients did not fulfill the clinical criteria for cirrhosis. The cutoff of LSM for cirrhosis was 10.3 kPa.

RESULTS

All patients were divided into either group A (cirrhosis) or group B (CHB) according to LB result. The median LSM values of groups A and B were 11.8 and 7.6 kPa, respectively (P < 0.001). The sensitivity, specificity, positive predictive value, and negative predictive value of LSM in predicting cirrhosis were 0.59, 0.78, 0.68, and 0.72, respectively. The area under the receiver operating characteristics curve (AUROC) of LSM was 0.803, whereas the AUROCs of aspartate to alanine aminotransferase ratio (AAR) and aspartate aminotransferase to platelet ratio index (APRI) were 0.488 and 0.723, respectively.

CONCLUSIONS

LSM showed an acceptable diagnostic accuracy for detecting early compensated cirrhosis in CHB.

Liver stiffness measurement in combination with noninvasive markers for the improved diagnosis of B-viral liver cirrhosis

GOAL

To investigate the performance of liver stiffness measurement (LSM) in combination with available noninvasive markers in hepatitis B virus-related chronic liver disease.

BACKGROUND

Few noninvasive methods are available for predicting liver cirrhosis in chronic hepatitis B (CHB).

STUDY

Between January 2006 and June 2007, we studied 130 consecutive treatment-naive CHB patients who underwent liver biopsy (LB) and LSM. The aspartate to alanine aminotransferase ratio, age-platelet index (API), aspartate aminotransferase to platelet ratio index (APRI), LSM, and their combinations were compared with liver histology.

RESULTS

The API, APRI, and LSM, but not the aspartate to alanine aminotransferase ratio, correlated significantly with liver cirrhosis (all P<0.001). The diagnostic accuracy of LSM and API exceed that of the other diagnostic methods for predicting liver cirrhosis (area under the receiver operating characteristic curve=0.840 and 0.818). When LSM was combined with API and APRI, the diagnostic accuracy was improved markedly (area under the receiver operating characteristic curve =0.871, and 0.846). When both LSM and API results were in agreement, LB confirmed them in 89.1% (41/46) of cases for liver cirrhosis. LB could have been avoided in 41 (31.5%) of the 130 patients who were examined for the potential diagnosis of liver cirrhosis.

CONCLUSIONS

The combination of LSM and API can avoid unnecessary invasive LB procedures in CHB patients.

Inhibition of HBV gene expression and replication by stably expressed interferon-alpha1 via adeno-associated viral vectors

Background

Interferon‐α2 (IFNα2) is routinely used for anti‐hepatitis B virus (HBV) treatment. However, the therapeutic efficiency is unsatisfactory, particularly in East Asia. Such inefficiency might be a result of the short half‐life, relatively low local concentration and strong side‐effects of interferons. Frequent and repeated injection is also a big burden for patients. In the present study, a single dose of vector‐delivered IFNα1 was tested for its anti‐HBV effects.

Methods

Adeno‐associated viral vector (AAV‐IFNα1) was generated to deliver the IFNα1 gene into hepatocytes. IFNα1, hepatitis B surface (HBsAg) and e (HBeAg) antigens were measured by enzyme‐linked immunosorbent assay and/or western blotting. The level of viral DNA was measured by quantitative real‐time polymerase chain reaction.

Results

AAV‐IFNα1 effectively transduced HBV‐producing cells (HepAD38) and mouse hepatocytes, where IFNα1 was expressed in a stable manner. Both intracellular and extracellular HBsAg and HBeAg were significantly reduced in vitro. In the HBV‐producing mice, the concentration of IFNα1 in the liver was eight‐fold higher than that in plasma. Compared with control groups, HBeAg/HBsAg antigen levels were reduced by more than ten‐fold from day 1–5, and dropped to an undetectable level on day 9 in the AAV‐IFNα1 group. Concurrently, the level of viral DNA decreased over 30‐fold for several weeks.

Conclusions

A single dose administration of AAV‐IFNα1 viral vector displayed prolonged transgene expression and superior antiviral effects both in vitro and in vivo. Therefore, the use of AAV‐IFNα1 might be a potential alternative strategy for anti‐HBV therapy. Copyright © 2008 John Wiley & Sons, Ltd.

Treatment of chronic hepatitis B: recommendations from an Italian workshop

The changing scenario of hepatitis B virus therapy has encouraged the organisation of a workshop, endorsed by three Italian scientific societies, aimed at defining the current recommendations for hepatitis B virus treatment. Liver histology and stage of disease remain fundamental for treatment decisions; interferon and nucleoside/nucleotide analogues-based therapy represent different strategies for different phases of the hepatitis B virus disease. The recommendations defined: new and lower cut-off of hepatitis B virus-DNA for eligibility to therapy according to disease stage, how to optimise the use of nucleoside/nucleotide analogues and to individualise the monitoring of response and what to do with treatment failures. Specific recommendations have also been given for cirrhosis patients, those immune suppressed and co-infected with HIV and other hepatitis viruses.

Replication of clinical hepatitis B virus isolate and its application for selecting antiviral agents for chronic hepatitis B patients

AIM: To establish a cell model harboring replicative clinical hepatitis B virus (HBV) isolates and evaluate its application in individualized selection of anti-HBV agents for chronic hepatitis B (CHB) patients.

METHODS: The full-length HBV genomic DNA from 8 CHB patients was amplified by polymerase chain reaction (PCR). All the patients were treated with lamivudine for at least seven months and finally became resistant to lamivudine. The amplified HBV DNA fragments were inserted into pHY106 vectors by Sap I digestion. The recombinant plasmids containing 1.1 copies of HBV genome were transiently transfected into Huh7 cell line, and the levels of HBsAg, HBeAg and intercellular HBV replicative intermediates were determined by ELISA and Southern blot analysis, respectively, with or without lamivudine and adefovir treatment. The antiviral treatment with adefovir was administered to the patients and analyzed in parallel.

RESULTS: A total of 25 independent HBV isolates were obtained from the sera of 8 patients, each patient had at least two isolates. One isolate from each individual was selected and subcloned into pHY106 vector, including 5 isolates with YVDD mutation and 3 isolates with YIDD mutation. All recombinant plasmids harboring HBV isolates were transfected into Huh7 cells. The results indicated that HBV genome carried in HBV replicons of clinical HBV isolates could effectively replicate and express in Huh7 cells. Adefovir, but not lamivudine, inhibited HBV replication both in vitro and in vivo, and in vitro inhibition was dose-dependent.

CONCLUSION: The novel method described herein enables individualized selection of anti-HBV agents in clinic and is useful in future studies of antiviral therapy for CHB.

Lamivudine-resistant chronic hepatitis B: an observational study on adefovir in monotherapy or in combination with lamivudine

BACKGROUND/AIMS

In lamivudine-resistant patients with chronic hepatitis B (CHB), we compared efficacy, predictive response factors and changes in viral mutants in two antiviral approaches with adefovir.

METHODS

A prospective cohort study on therapy with adefovir alone (29 patients) or combined with ongoing lamivudine (23 patients) was performed.

RESULTS

A virological response was achieved in 55% of patients treated with adefovir and in 83% of those treated with the combination (p>0.05). This response was directly related to the basal viral load (p<0.0001) and obtained in 10 patients with basal HBV-DNA<17,200 IU/ml using both strategies. In patients with a higher basal viral load, the virological response was more frequent when treated with the combination (p<0.05). Mutation at locus rt181 predicted HBV-DNA persistence during therapy. A virological rebound was observed in 18% of non-responders while on adefovir monotherapy.

CONCLUSIONS

To achieve a complete virological response and reduce the risk of adefovir-resistant mutants in lamivudine-resistant patients, rescue therapy is preferable at early evidence of genotypic resistance. However, in subjects with a significant viral load, combination therapy is more effective. The presence of the rt181 mutation is associated with incomplete response.

Combination adefovir-lamivudine prevents emergence of adefovir resistance in lamivudine-resistant hepatitis B

BACKGROUND AND AIM

The outcomes of lamivudine-resistant chronic hepatitis B patients treated with long-term adefovir dipivoxil have not been well described. This study aims to characterize the virological and biochemical response and to determine factors that may influence the development of resistance to adefovir.

METHODS

A retrospective review was conducted on all patients with lamivudine-resistant chronic hepatitis B treated with adefovir for a minimum of 6 months at two tertiary referral centers.

RESULTS

Data on 161 patients were analyzed. Seventy-two percent achieved an initial virological response with eventual normalization of alanine aminotransferase in only 67% of patients. Seventeen patients developed adefovir resistance with cumulative resistance rates of 3.2%, 8.8%, and 18% at 12, 24, and 36 months, respectively. Twelve (71%) of these patients had a biochemical breakthrough, with one death from fulminant hepatic failure. The median duration of lamivudine crossover was 1 month in adefovir-resistant patients, compared with 12 months for the remainder of the cohort (P < 0.01). Longer crossover therapy reduced the adefovir resistance rate, but did not eliminate it. No adefovir resistance is reported in those who were continued on long-term combination lamivudine-adefovir without a period of adefovir monotherapy.

CONCLUSIONS

Combination lamivudine-adefovir therapy protected against the emergence of adefovir resistance.

Noninvasive models to predict liver cirrhosis in patients with chronic hepatitis B

OBJECTIVES

Few noninvasive models of chronic hepatitis B (CHB) to predict liver cirrhosis have been studied. The aim of the current study is to investigate the diagnostic accuracy of two simple novel models of spleen-platelet ratio index (SPRI) and age-spleen-platelet ratio index (ASPRI) in patients with CHB.

PATIENTS AND METHODS

A total of 346 consecutive treatment-naïve patients with CHB were retrospectively studied. The aspartate to alanine aminotransferase ratio (AAR), age-platelet index (API), aspartate aminotransferase to platelet ratio index (APRI), SPRI, and ASPRI were compared with liver histology.

RESULTS

AAR, APRI, SPRI, API, and ASPRI correlated significantly to fibrosis stage (all P<0.001). The diagnostic accuracy of ASPRI was the highest among five tests for prediction of cirrhosis (area under receiver operating characteristic curve, AUROC=0.893). Using a cutoff score of ASPRI>12, the presence of cirrhosis could be correctly identified with a high accuracy (96.3% positive predictive value) in 35 (10.1%) of 346 patients. Similarly, using a cutoff of <5, the presence of cirrhosis could be totally excluded with 100% of negative predictive value in 120 (34.7%) of 346 patients.

CONCLUSION

ASPRI was accurate in predicting cirrhosis and screening with ASPRI has the potential to reduce the number of liver biopsies in CHB patients.

Improving outcomes for patients with chronic hepatitis B

A focused meeting on hepatitis B virus (HBV) infection was held at the United States National Institutes of Health in Washington, DC, in April 2006. This meeting focused on new and historical data and served as a review for basic scientists and clinicians, as well as representatives from the pharmaceutical industry. Understanding HBV disease must include up-to-date information concerning virology, immunology, animal models, natural history, prevalence, and transmission risk, as well as an understanding of the evolving therapies for this life-threatening infection. Serious outcomes such as advanced fibrosis, cirrhosis, liver failure and hepatocellular carcinoma from hepatitis B infection appear to be closely tied to both historical and current serum levels of HBV DNA, and elevated serum levels of liver enzymes. Decreasing risk events and vaccinating susceptible individuals are key steps in managing this global scourge. New oral treatments for patients withchronic hepatitis B infection characterized by more potent antiviral effects, less toxicity, and minimal or no risk of resistance were reviewed and emphasized. Entecavir and pegylated interferons have recently been approved for treatment of chronic hepatitis B. Further expansion of our information about lamivudine and adefovir were highlighted. Several other new anti-HBV agents are also in phase II or III clinical trials or have been submitted for licensing including LdT (telbivudine). The NIH review meeting is summarized in this review and new and emerging areas of information are highlighted.

Targets of emerging therapies for viral hepatitis B and C

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