Treatment of recurrent hepatitis C in liver transplant is controversial. The aim of our study was to evaluate the clinical and histological efficacy of pegylated interferon alpha 2b (PEG-IFN) and ribavirin therapy of recurrent hepatitis C after liver transplantation (LT). We prospectively included 47 liver transplant patients with: 1) a positive test for hepatitis C virus (HCV)-ribonucleic acid (RNA) in serum; 2) alanine aminotransferase (ALT) Ͼ45 IU/L; and 3) a liver biopsy showing chronic hepatitis without rejection in the previous 2 months. Patients received PEG-IFN (1.5 g/kg/week) and ribavirin (800-1,000 mg/day) for 12 months. Follow-up was based on biochemical (ALT), virological (RNA-HCV), and histological (liver biopsy) examinations. Follow-up lasted a minimum of 6 months after the end of antiviral therapy. Sustained virological response (SVR) was achieved in 23% of the patients. A total of 33 (70%) patients had normalized ALT levels at the end of therapy. Inflammatory portal and lobular score declined significantly in patients with SVR (P Ͻ 0.05) but not in nonresponder patients. Fibrosis did not change significantly in either group. SVR was significantly associated with low ␥-glutamyltransferase GGT (P ϭ 0.04) and HCV-RNA levels (P ϭ 0.03), a virological response at 12 weeks (P ϭ 0.002) and patient's compliance (P ϭ 0.04). Ten (21%) patients were withdrawn prematurely due to adverse effects. In conclusion, Therapy with PEG-IFN and ribavirin achieved SVR and a significant histological improvement in 23% of liver transplant recipients with chronic hepatitis C. Toxicity is an important drawback of this therapy.

The mechanism of tumor necrosis factor ␣ (TNF␣)-induced cytotoxicity in metabolically inhibited cells is unclear, although some studies have suggested that mitochondrial dysfunction and generation of reactive oxygen species may be involved. Here we studied the effect of TNF␣ on the redox state of mitochondrial cytochromes and its involvement in the generation of reactive oxygen species in metabolically inhibited L929 cells. Treatment with TNF␣ and cycloheximide (TNF␣/CHX) induced mitochondrial cytochrome c release, increased the steady-state reduction of cytochrome b, and decreased the steady-state reduction of cytochromes cc 1 and aa 3 . TNF␣/CHX treatment also induced lipid peroxidation, intracellular generation of reactive oxygen species, and cell death. Furthermore, as the cells died mitochondrial morphology changed from an orthodox to a hyperdense and condensed and finally to a swollen conformation. Antimycin A, a mitochondrial respiratory chain complex III inhibitor that binds to cytochrome b, blocked the formation of reactive oxygen species, suggesting that the free radicals are generated at the level of cytochrome b. Moreover, antimycin A, when added after 3 h of TNF␣/CHX treatment, arrested the further release of cytochrome c and the cytotoxic response. We propose that the reduced cytochrome b promotes the formation of reactive oxygen species, lipid peroxidation of the cell membrane, and cell death. Tumor necrosis factor ␣ (TNF␣)1 is a cytokine that is cytotoxic against certain tumor cells (1), and this effect is enhanced by cycloheximide (CHX) (2). In the presence of CHX not only is less TNF␣ required, but also cell death occurs in a shorter period of time (3). Although these effects have been described extensively, the molecular mechanisms of action are not well understood (4, 5). The reported ability of antioxidants to protect cells against TNF␣-induced cytotoxicity suggests that mitochondrial dysfunction and generation of reactive oxygen species (ROS) in the mitochondria may play an essential role (6 -11). Oxidative stress can result in severe metabolic dysfunction, including the peroxidation of lipid membranes (12), an increase in cytosolic Ca 2ϩ (13), induction of the mitochondrial permeability transition (14), and DNA damage (reviewed in Refs. 15 and 16).Previous investigations have shown contradictory results regarding whether TNF␣ induces cytotoxicity through necrosis or apoptosis (17). Recent results indicate that TNF␣ induces necrosis in L929 cells, although apoptosis-like features have also been observed (18,19). Regardless of the mode of cell death, however, it has been shown that TNF␣-induced cytotoxicity of L929 cells is mediated by mitochondrial formation of ROS (20,21). In intact mitochondria, three components of the respiratory chain have been found to be involved in the generation of ROS (22, 23); one is located in complex I, and the other two are ubisemiquinone (24) and reduced cytochrome b (25, 26), which are both located in complex III. Furthermore, substantial evidence in other sy...

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The role of IL-6 in collagen production and tissue remodeling is controversial. In Rat-1 fibroblasts, we measured the effect of IL-6 on matrix metalloproteinase-13 (MMP-13), c-jun, junB, and c-fos gene expression, binding of activator protein 1 (AP1) to DNA, amount of AP1 proteins, immunoreactive MMP-13 and TIMP-1 proteins, and Jun N-terminal kinase activity. We show that IL-6 increased MMP-13-mRNA and MMP-13 protein. These effects were exerted by acting on the AP1-binding site of the MMP-13 promoter, as shown by transfecting cells with reporter plasmids containing mutations in this element. Mobility shift assays demonstrated that IL-6 induced the DNA binding activity of AP1. This effect was accompanied by a marked increase in c-Jun, JunB, and c-Fos mRNA, as well as in c-Jun protein and its phosphorylated form. The latter is not due to increased Jun N-terminal kinase activity but to a decreased serine/ threonine phosphatase activity. We conclude that IL-6 increases interstitial MMP-13 gene expression at the promoter level. This effect seems to be mediated by the induction of c-jun, junB, and c-fos gene expression, by the binding of AP1 to DNA, by increasing phosphorylated c-Jun, and by the inhibition of serine/threonine phosphatase activity. These effects of IL-6 might contribute to remodeling connective tissue.

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