Project description:Background/Aims: Ribavirin improves treatment response to pegylated-interferon (PEG-IFN) in chronic hepatitis C but the mechanism remains controversial. We studied correlates of response and mechanism of action of ribavirin in treatment of hepatitis C. Methods: 70 treatment-naïve patients were randomized to 4 weeks of ribavirin (1000-1200 mg/d) or none, followed by PEG-IFN alfa-2a and ribavirin at standard doses and durations. Patients were randomized to undergo a liver biopsy either 24 hours before, or 6 hours after starting PEG-IFN. Hepatic gene expression was assessed by microarray and interferon-stimulated gene (ISG) expression quantified by the nCounter platform. Temporal changes in ISG expression were assessed by qPCR in peripheral-blood mononuclear cells (PBMC) and by serum levels of IP-10. Results: After four weeks of ribavirin monotherapy, HCV levels decreased by 0.5±0.5 log10 (p=0.009 vs. controls) and ALT by 33% (p<0.001). Ribavirin pretreatment, while modestly augmenting the induction of ISGs by PEG-IFN, did not modify the virological response to subsequent PEG-IFN and ribavirin treatment. However, biochemical, but not virological response to ribavirin monotherapy predicted response to subsequent combination treatment (rapid virological response, 71% in biochemical responders vs. 22% non-responders, p=0.01; early virological response, 100% vs. 68%, p=0.03, sustained virological response 83% vs. 41%, p=0.053). Ribavirin monotherapy lowered serum IP-10 levels but had no effect on ISG expression in PBMC. Conclusion: Ribavirin is a weak antiviral but its clinical effect in combination with PEG-IFN seems to be mediated by a separate, indirect mechanism, which may act to reset the interferon responsiveness in HCV-infected liver. Ribavirin pretreatment does not alter the clinical outcome of subsequent combination therapy. Analysis of liver biopsy samples from 52 patients under 4 different treatment conditions.
Project description:Background/Aims: Ribavirin improves treatment response to pegylated-interferon (PEG-IFN) in chronic hepatitis C but the mechanism remains controversial. We studied correlates of response and mechanism of action of ribavirin in treatment of hepatitis C. Methods: 70 treatment-naïve patients were randomized to 4 weeks of ribavirin (1000-1200 mg/d) or none, followed by PEG-IFN alfa-2a and ribavirin at standard doses and durations. Patients were randomized to undergo a liver biopsy either 24 hours before, or 6 hours after starting PEG-IFN. Hepatic gene expression was assessed by microarray and interferon-stimulated gene (ISG) expression quantified by the nCounter platform. Temporal changes in ISG expression were assessed by qPCR in peripheral-blood mononuclear cells (PBMC) and by serum levels of IP-10. Results: After four weeks of ribavirin monotherapy, HCV levels decreased by 0.5±0.5 log10 (p=0.009 vs. controls) and ALT by 33% (p<0.001). Ribavirin pretreatment, while modestly augmenting the induction of ISGs by PEG-IFN, did not modify the virological response to subsequent PEG-IFN and ribavirin treatment. However, biochemical, but not virological response to ribavirin monotherapy predicted response to subsequent combination treatment (rapid virological response, 71% in biochemical responders vs. 22% non-responders, p=0.01; early virological response, 100% vs. 68%, p=0.03, sustained virological response 83% vs. 41%, p=0.053). Ribavirin monotherapy lowered serum IP-10 levels but had no effect on ISG expression in PBMC. Conclusion: Ribavirin is a weak antiviral but its clinical effect in combination with PEG-IFN seems to be mediated by a separate, indirect mechanism, which may act to reset the interferon responsiveness in HCV-infected liver. Ribavirin pretreatment does not alter the clinical outcome of subsequent combination therapy.
Project description:The combination of peginterferon and ribavirin is the standard treatment for chronic hepatitis C. Our recent clinical study suggests that ribavirin augments the induction of interferon stimulated genes (ISGs) in patients treated for HCV infection [1]. In order to further characterize the mechanisms of action of ribavirin, we examined the effect of ribavirin treatment on ISG induction in cell culture. In addition, the effect of ribavirin on infectious HCV cell culture systems was also studied. Similar to interferon-alpha, ribavirin potently inhibits JFH-1 infection of Huh7.5.1 cells in a dose-dependent manner, which spans the physiological concentration of ribavirin in vivo. Microarray analysis and subsequent quantitative PCR assays demonstrated that ribavirin treatment resulted in the induction of a distinct set of ISGs. These ISGs, including IRF7 and IRF9 are known to play an important role in anti-HCV responses. When ribavirin is used in conjunction with interferon, induction of specific ISGs is synergistic when compared to either drug applied separately. Direct up-regulation of these antiviral genes by ribavirin is mediated by a novel mechanism different from those associated with interferon signaling and intracellular double stranded RNA sensing pathways such as RIG-I and MDA5. RNA interference studies excluded the activation of the Toll-like receptor and NF-KappaB pathways in the action of ribavirin. In conclusion, our study suggests that ribavirin, acting via a novel innate mechanism, potentiates the anti-HCV effect of interferon. Understanding the mechanism of action of ribavirin would be valuable in identifying novel antivirals. RNA from three samples were treated with Ribavirin and compared to three PBS treated samples
Project description:The combination of peginterferon and ribavirin is the standard treatment for chronic hepatitis C. Our recent clinical study suggests that ribavirin augments the induction of interferon stimulated genes (ISGs) in patients treated for HCV infection [1]. In order to further characterize the mechanisms of action of ribavirin, we examined the effect of ribavirin treatment on ISG induction in cell culture. In addition, the effect of ribavirin on infectious HCV cell culture systems was also studied. Similar to interferon-alpha, ribavirin potently inhibits JFH-1 infection of Huh7.5.1 cells in a dose-dependent manner, which spans the physiological concentration of ribavirin in vivo. Microarray analysis and subsequent quantitative PCR assays demonstrated that ribavirin treatment resulted in the induction of a distinct set of ISGs. These ISGs, including IRF7 and IRF9 are known to play an important role in anti-HCV responses. When ribavirin is used in conjunction with interferon, induction of specific ISGs is synergistic when compared to either drug applied separately. Direct up-regulation of these antiviral genes by ribavirin is mediated by a novel mechanism different from those associated with interferon signaling and intracellular double stranded RNA sensing pathways such as RIG-I and MDA5. RNA interference studies excluded the activation of the Toll-like receptor and NF-KappaB pathways in the action of ribavirin. In conclusion, our study suggests that ribavirin, acting via a novel innate mechanism, potentiates the anti-HCV effect of interferon. Understanding the mechanism of action of ribavirin would be valuable in identifying novel antivirals.
Project description:In this study we aimed to identify a baseline intrahepatic transcriptional signature associated with response in chronic hepatitis B patients treated with peginterferon-alfa-2a (peg-IFN) and adefovir. Liver gene expression values of patients with combined response (responders; n=9) and non-response (n=6) were compared for 21,462 annotated gene transcripts. We identified 182 genes which differed on average more than 1.5-fold, of which 53 were relatively upregulated in non-responders and 129 in responders. 15 liver biopsies of chronic hepatitis B patients were selected for RNA extraction and hybridization on Affymetrix microarrays. Expression values in 9 biopsies of patients with a combined response to therapy were compared with 6 biopsies of non-responders. Differentially expressed genes between responders and non-responders were determined using filtering on minimal average expression, fold change (1.5 fold) and p-values from 2-sided t-tests (0 permutations) in GenePattern. This dataset is part of the TransQST collection.
Project description:In this study we aimed to identify a baseline intrahepatic transcriptional signature associated with response in chronic hepatitis B patients treated with peginterferon-alfa-2a (peg-IFN) and adefovir. Liver gene expression values of patients with combined response (responders; n=9) and non-response (n=6) were compared for 21,462 annotated gene transcripts. We identified 182 genes which differed on average more than 1.5-fold, of which 53 were relatively upregulated in non-responders and 129 in responders.
Project description:With 350 million carriers worldwide who may suffer from serious sequelae, including hepatocellular carcinoma, chronic hepatitis B virus (CHB) infection remains an important health issue. Current antiviral therapies hardly eradicate the virus. Therefore, there are still imperative need to develop new therapeutic strategies and predictors for treatment response to cure the disease and avoid futile treatment. By taking the advantage of having the paired liver biopsy samples of IFNalpha responders before/after treatment and pretreatment samples from responders and non-responders, we could characterize the intrahepatic expression profiles associated with necroinflammatory activity and the profiles/signature potentially predictive of response to IFNalpha therapy for CHB in this study. RNA was extracted from pairedliver tissues for gene expression analysis. The gene expression profiles of seven paired liver biopsy samples of IFNalpha responders before/after treatment and other 3 pre- treatment samples were obtained by Affymatrix U133plus2 microarray. We also pooled samples of 11 responders and 11 non-responders to perform affymatrix EXON ST 1.0 array. This dataset is part of the TransQST collection.