Viral hepatitis and liver transplantation
ABSTRACT Hepatitis C is the one of the most common indications for liver transplantation. Infection of the allograft after transplantation is universal, and recurrent hepatitis C progresses at an accelerated rate. Antiviral therapy in selected patients on the transplant waiting list may reduce the rate of hepatitis C virus reinfection. Preemptive antiviral therapy after transplantation has been disappointing. However, treatment of established histological disease with a combination of pegylated interferon and ribavirin is associated with sustained virologic response rates of 25 to 40%. Significant advances have been made in the prevention of hepatitis B reinfection after transplantation. Results are now excellent, with graft infection rates less than 10%. The challenges for the future include designing strategies to optimize the use of antiviral agents to prevent the need for transplantation and to avoid antiviral resistance and to determine the dose and duration of hepatitis B immunoglobulin needed in the era of multiple nucleoside analogs.
SourceAvailable from: PubMed Central01/2013; 6(1):1-5.
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ABSTRACT: Introduction Pegylated interferon and ribavirin (PEG-IFN/RBV) therapy for recurrent hepatitis C after liver transplantation (LT) is associated with a lower sustained virological response (SVR) rate as well as more frequent side effects compared to non-transplant patients. We aimed to determine the incidence and clinical characteristics of LT recipients with recurrent hepatitis C who developed immunological dysfunction (ID) during or after PEG-IFN/RBV therapy and to assess its impact on patient and graft survival. Methods Seventy-four deceased donor LT recipients with histological recurrence of hepatitis C were treated with PEG-IFN/RBV from 1/00 to 12/08. ID was defined as biopsy-proven rejection or moderate plasma cell hepatitis. Patients were followed up until death, re-LT or 30 September 2011. Results Twelve patients (16 %) had ID, 8 (10.7 %) had cholestasis without ID, while 54 had no ID/cholestasis during or after discontinuation of PEG-IFN/RBV therapy. Biopsy-proven acute cellular rejection prior to (hazard ratio = 4.87, p = 0.009) and type of immunosuppression at the time of initiation of PEG-IFN/RBV were the only independent predictors of ID. Patients who were on tacrolimus at the time of initiation of PEG-IFN/RBV had a significantly lower risk of ID compared to those who were on cyclosporine (HR 0.254, p = 0.023). Patients with ID had a trend toward a lower SVR rate (25 vs. 54 %, p = 0.18) and a significantly higher rate of graft failure (33 vs. 4 %, p = 0.004) compared to patients with no ID/cholestasis. Conclusions ID is common during or after PEG-IFN/RBV therapy for recurrent hepatitis C and frequently associated with decreased graft survival, trending toward low rates of SVR. Careful monitoring of liver biochemistries during or after PEG-IFN/RBV therapy with a low threshold to biopsy patients and particularly those receiving cyclosporine-based immunosuppression may improve outcomes in these patients.Hepatology International 10/2013; 7(4). DOI:10.1007/s12072-013-9436-1 · 2.47 Impact Factor
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ABSTRACT: Ribavirin (RBV), a broad-spectrum antiviral agent, is a standard medication against hepatitis C virus (HCV). However, despite the decades of clinical success, the mechanism of action of this drug against HCV remains a subject of debate. Furthermore, the appeal of this therapeutic agent is considerably lessened by unfavorable pharmacokinetics. This interdisciplinary study contributes to the understanding of intracellular effects exerted by RBV and presents a successful design of macromolecular prodrugs of RBV to achieve a safer treatment. Specifically, we demonstrate that RBV exhibits a pronounced anti-inflammatory activity in cultured macrophages as is evidenced by a 2-fold decrease in the levels of produced nitric oxide achieved using a clinically relevant concentration of this drug. However, this effect was characterized by a rather narrow therapeutic window with experimental values of EC50 and IC50 being 7 and 19 μM, respectively. Macromolecular prodrugs were obtained using an acrylate derivative of RBV, RAFT polymerization technique, and N-vinyl pyrrolidone as a partner monomer. The synthesized polymers were characterized with uniform molecular weights, relatively narrow polydispersities, and gradually increasing content of RBV. The resulting polymer therapeutics were effective in delivering their payload to the cultured macrophages and afforded a significantly wider therapeutic window, as much as >1000 μM (18-fold in relative values). Taken together, this work contributes significantly to the development of safer methods for delivery of RBV, as well as understanding the mechanism of action and origins of the side effects of this broad-spectrum antiviral agent.Biomacromolecules 10/2013; 14(11). DOI:10.1021/bm401048s · 5.79 Impact Factor