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A NON-INVASIVE TEST FOR HEPATIC FIBROSIS AND SCREEN FOR ANTIFIBROTIC DRUGS
TC Peterson1,2, KM Peltekian1, MR Peterson1, F Khan2
Division of Gastroenterology, 1Departments of Medicine, and 2Pharmacology, Dalhousie University, Halifax, Nova Scotia
INTRODUCTION: Hepatic stellate cell (HSC) proliferation is one of the hallmarks of hepatic fibrosis. Phosphorylation of c-Jun immediate early gene is essential for transcription of genes for growth and proliferation and may play a role in HSC proliferation in hepatic fibrosis. The FSI is a non-invasive test developed here and it allows the screening on potential antifibrotic drugs.
HYPOTHESES: Sera samples obtained from patients will stimulate proliferation of HSCs. Ribavirin and interferon will inhibit the proliferation of HSCs (stimulated to proliferate with HCV patient sera). Phosphorylation of c-Jun may be involved in the proliferation of HSCs and interferon (IFN alpha) and/or Ribavirin may work via inhibit of the phosphorylation of c-Jun.
DESIGN AND METHODS: Sera samples were obtained from patients with HCV. FSI was determined as an index from data obtained from thymidine incorporation assays using HSCs as the target cell. Immunocytochemistry (ICC) and western analysis was done on HSCs using a specific antibody to phosphorylated c-Jun.
RESULTS: HCV patient sera (PS) significantly stimulated (* =p<0.05) HSC proliferation. Ribavirin (Rib) alone or in combination with interferon alpha (IFN) significantly (**=p<0.05) inhibited HCV sera (PS) stimulated HSC proliferation. Nuclear staining of phosphorylated c-Jun was evident in HSCs stimulated with HCV patient sera as shown by ICC. Western analysis showed that ribavirin and pentoxifylline (PTX) significantly decreased the phosphorylated c-Jun in HSCs that were treated with HCV sera; while IFN had no effect.
CONCLUSIONS: FSI is an effective way to screen potential antifibrotic drugs. HCV patient sera stimulated HSC proliferation and phosphorylated c-Jun in HSCs. Ribavirin (but not interferon) inhibited phosphorylation of HSC c-Jun, thus blocking activation of c-Jun and effectively blocking the PDGF-mediated pathway that usually leads to increased HSC proliferation and increased collagen synthesis in HSCs, the two hallmarks of hepatic fibrosis. (supported by CIHR, Innovacorp and ACOA).