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In hepatitis C virus (HCV)-positive liver transplant recipients, infection of the allograft and recurrent liver disease are important problems. Increased donor age has emerged as an important variable affecting patient and graft survival; however, specific age cutoffs and risk ratios for poor histologic outcomes and graft survival are not clear.

Chronic hepatitis C virus (HCV) infection leads to increased oxidative stress in the liver. Hepatic antioxidant enzymes provide an important line of defense against oxidative injury. To understand the antioxidant responses of hepatocytes to different HCV proteins, we compared changes in antioxidative enzymes in HCV‐core and HCV‐nonstructural protein expressing hepatocyte cell lines. We found that expression of HCV‐core protein in hepatocyte cell lines leads to increased oxidative stress as determined by increased in the oxidant‐sensitive probe 5‐(and‐6)‐chloromethyl‐2′,7′‐dichlorodihydrofluorescein diacetate (CM‐DCFH2) fluorescence, decreased reduced glutathione (GSH), and increased oxidation of thioredoxin (Trx). Although the expression of HCV‐nonstructural (HCV‐NS) proteins led to increased oxidative stress as well, the antioxidant enzymatic responses were different. Over‐expression of HCV‐NS proteins increased antioxidant enzymes (MnSOD and catalase), heme oxygenase‐1 (HO‐1), and GSH, indicating different mechanism(s) of prooxidative activity than HCV‐core protein. Our findings show that different HCV proteins induce different antioxidant defense responses in hepatocytes. These findings may facilitate understanding the interaction of different HCV proteins with infected liver cells and help identify possible factors contributing to hepatocyte damage during HCV infection. J. Med. Virol. 76:489–497, 2005. © 2005 Wiley‐Liss, Inc.

Recurrent hepatitis C virus (HCV) infection in patients after liver transplantation is an important clinical problem. Because serum cryoglobulins (CG) are known to be associated with an increased incidence of cirrhosis in nontransplant patients, the authors tested the hypothesis that CG would also predict aggressive recurrent HCV in patients after liver transplantation.

GB virus type C (GBV-C) causes persistent infection in humans, although the mechanism by which the virus avoids clearance by the host is unknown. To determine if amino acid polymorphisms in the GB virus type C (GBV-C) NS5A and E2 proteins alter response to interferon (IFN) therapy, we studied the sequence of GBVC NS5A and E2 obtained from people receiving IFN therapy. In addition, we expressed recombinant GBVC NS5A protein to determine if it interferes with RNA-activated protein kinase (PKR) function in vitro. GBVC NS5A amplified from a person whose virus was cleared by IFN therapy (IFN sensitive) demonstrated unique amino acid changes occurring in the region that aligns with the hepatitis C virus (HCV) IFN sensitivity-determining region (ISDR) compared with NS5A sequences from individuals who did not clear GBV-C (IFN resistant). There were no differences in the E2 sequences obtained from IFN-sensitive and IFN-resistant isolates. Using a yeast genetic system, IFN-resistant NS5A inhibited PKR-mediated phosphorylation of eukaryotic initiation factor 2α (eIF2α) in yeast, whereas IFN-sensitive NS5A did not inhibit PKR function. GBV-C NS5A amino acid polymorphisms appear to be involved in response to IFN therapy, and IFN-resistant GBV-C NS5A inhibited PKR-mediated eIF2α phosphorylation in a yeast genetic system, suggesting a mechanism by which GBV-C may evade clearance by naturally occurring host antiviral responses.

Hepatitis C virus (HCV) and HCV core protein are hypothesized to induce hepatic oxidative stress and exacerbate injury caused by other toxins such as ethanol that induce the cytochrome P450 enzyme, CYP2E1. In the current study, the effects of HCV core protein [sequence genotype 1b, (nt 342–915)] on parameters indicative of oxidative stress were evaluated in HepG2 cells stably over expressing CYP2E1 (E47), or vector controls (C34). Stable (>10 passages) expression of HCV core protein and CYP2E1 was confirmed in clonal cell lines at the level of mRNA and immunoreactive protein. Prooxidant production, as determined by cellular oxidation of dichlorodihydrofluorescin and dihydroethidium (HE), was increased by expression of HCV core protein in the presence or absence of CYP2E1. Depletion of glutathione (GSH) with buthionine sulfoximine (BSO) enhanced prooxidant production in both C34 and E47 cells. In addition, prooxidant production was greater in BSO‐treated cells expressing HCV core protein, and this effect was further enhanced in cells expressing both HCV core and CYP2E1. The CYP2E1 inhibitor, 4‐methylpyrazole, could suppress increased prooxidant production in E47 cells. Finally, cells co‐expressing both CYP2E1 and HCV core protein showed significantly decreased viability following GSH depletion. These studies show simultaneous expression of HCV core protein and CYP2E1 increases parameters indicative of oxidative stress as well as sensitization to cell injury induced by GSH depletion. These results support the hypothesis that enhanced injury in hepatocytes over expressing both HCV core protein and CYP2E1 is mediated by increases in oxidative stress. J. Med. Virol. 72:230–240, 2004. © 2004 Wiley‐Liss, Inc.

Hepatitis C virus (HCV) is difficult to study due to the lack of an efficient cell culture system or small animal model. As a result, HCV–cell interactions are not well‐defined. In addition, several studies have identified a subset of patients in whom HCV RNA is present, but HCV antibody is not detected. We produced recombinant baculoviruses that expressed HCV structural proteins (core, E1 and E2, nt 342–2651) or control proteins. The HCV structural protein precursor was processed into immunoreactive proteins of appropriate size, and sucrose density sedimentation and electron microscopy of infected cell lysates demonstrated particle formation. To evaluate HCV antigenicity, particularly in patients who tested negative for HCV antibody in commercial HCV immunoassays but had persistent viremia, we evaluated the virus‐like particles (VLPs) in solid‐phase immunoassays. VLPs reacted with sera from HCV antibody positive subjects in these solid phase immunoassays, but not with control sera. Plasma samples from 19% (5/26) of HCV antibody negative subjects who were persistently HCV RNA positive also reacted with the HCV VLPs. When incubated with MOLT‐4 cells at 4°C, HCV VLPs demonstrated cell binding, and behaved similar to plasma‐derived HCV preparations in a flow cytometry‐based cell binding assay. These data suggest that recombinant HCV VLPs may allow identification of HCV antibody in patients, including some patients with persistent viremia and who are seronegative with current assays. In addition, HCV VLPs seem useful for evaluating HCV–cell interactions. J. Med. Virol. 68:537–543, 2002. © 2002 Wiley‐Liss, Inc.

ABSTRACTHepatitis C virus (HCV) or HCV–low-density lipoprotein (LDL) complexes interact with the LDL receptor (LDLr) and the HCV envelope glycoprotein E2 interacts with CD81 in vitro. However, E2 interactions with LDLr and HCV interactions with CD81 have not been clearly described. Using sucrose gradient-purified low-density particles (1.03 to 1.07 g/cm3), intermediate-density particles (1.12 to 1.18 g/cm3), recombinant E2 protein, or control proteins, we assessed binding to MOLT-4 cells, foreskin fibroblasts, or LDLr-deficient foreskin fibroblasts at 4°C by flow cytometry and confocal microscopy. Viral entry was determined by measuring the coentry of a-sarcin, a protein synthesis inhibitor. We found that low-density HCV particles, but not intermediate-density HCV or controls bound to MOLT-4 cells and fibroblasts expressing the LDLr. Binding correlated with the extent of cellular LDLr expression and was inhibited by LDL but not by soluble CD81. In contrast, E2 binding was independent of LDLr expression and was inhibited by human soluble CD81 but not mouse soluble CD81 or LDL. Based on confocal microscopy, we found that low-density HCV particles and LDL colocalized on the cell surface. The addition of low-density HCV but not intermediate-density HCV particles to MOLT-4 cells allowed coentry of a-sarcin, indicating viral entry. The amount of viral entry also correlated with LDLr expression and was independent of the CD81 expression. Using a solid-phase immunoassay, recombinant E2 protein did not interact with LDL. Our data indicate that E2 binds CD81; however, virus particles utilize LDLr for binding and entry. The specific mechanism by which HCV particles interact with LDL or the LDLr remains unclear.

ABSTRACTWe previously demonstrated that whole blood contains significantly more hepatitis C virus (HCV) RNA than plasma. To validate the whole-blood-based HCV RNA detection method, a prospective comparison of HCV RNA detection in whole blood and plasma from 50 patients with chronic liver disease was undertaken. Whole-blood and plasma aliquots were independently tested for HCV RNA by reverse transcriptase (RT) PCR assay, and plasma was tested by the Roche Amplicor assay. HCV RNA was detected in 35 of 50 (70%) whole-blood samples by RT-PCR but in only 26 of 50 (52%) plasma samples tested by the Amplicor assay (P< 0.01). HCV RNA was detected in 85% of HCV antibody-positive patients by the whole-blood method compared with 74% of plasma samples by the Amplicor method. The five HCV antibody-positive subjects who were negative by whole-blood-based RT-PCR assay were all receiving interferon therapy and had normal transaminases at the time of testing. HCV RNA was detected in 38% of HCV antibody-negative subjects by the whole-blood-based RT-PCR assay compared with 6.25% of these patients by the Amplicor assay (P< 0.05). There were nine samples in which HCV RNA was detected in whole blood but the Amplicor test was negative. Eight of the nine RNAs prepared from these whole-blood samples tested positive in the Amplicor assay, thus confirming the specificity of our results. This study demonstrates that whole-blood-based HCV RNA detection is more sensitive than currently available commercial tests and that whole-blood RNA is suitable for use in commercial assays.

Sephadex G-25 chromatography has been used to examine cytosol prepared from 5–6-day-old cultures of immature rat Sertoli cells for the presence of macromolecular androgen and progesterone binding components. High affinity, slowly dissociable, androgen binding activity was detected that exhibited first-order half-times of dissociation (t½) of 3.2 ± 1.0 h for [3H]-testosterone and 3.5 ± 1.3 h for [3H]-5α-dihydrotestosterone. These dissociation rates clearly distinguish this androgen binding component from Androgen Binding Protein (ABP), which has a t½of ∿5 min. Specific binding of [3H]-testosterone to the non-ABP binding moiety was completely inhibited by a 100-fold molar excess of unlabeled testosterone, 5α-DHT, Δ6-testosterone, and progesterone. Specific binding of [3H]-progesterone was also observed. Approximately 20%–40% of the specific binding persisted 30 min after the addition of 100-fold molar excess of unlabeled progesterone to samples that had been equilibrated with [3H]-progesterone. Analysis of the dissociation of [3H]-progesterone bound to macromolecules with time revealed the presence of at least two binding components. One component showed a rapid rate of dissociation (t½∿ 13 min), and the other component showed a slow rate of dissociation (t½>5 h). Specific binding of [3H]-progesterone to the slowly and rapidly dissociating components showed similar but not identical sequences of binding specificity (slow component: P>5α-DHT>T = Δ6-T>R5020>MPA = E = F; rapid component: P>5α-DHT>R5020>T = 6Δ-T>MPA = E = F). Studies on the metabolism of [3H]-5α-DHT, [3H]-testosterone and [3H]-progesterone by Sertoli cell cytosol (3 h, 0°C-2°C) revealed that: 1) ∿50% of the [3H]-5α-DHT was converted to [3H]-5α-androstan-3α, 17β-diol, and 2) little (<5%) metabolism of [3H]-testosterone or (3H]-progesterone occurred. When the radioactivity specifically bound to macromolecular components in cytosol was examined, we determined that: 1) in incubations with [3H]-5α-DHT, 90% of the bound label was [3H]-5α-DHT; 2) in incubations with [3H]-testosterone, greater than 94% of the bound label was [3H]-testosterone; and 3) in incubations with [3H]-progesterone, greater than 98% of the bound label was [3H]-progesterone.

Cytoplasmic poly(A)+ RNA was isolated from normal rat liver and Novikoff ascites hepatoma cells, translated in vitro using rabbit reticulocyte lysate system and the translational products were assayed by immunoprecipitation with antibodies specific for Novikoff hepatoma principal cytokeratins p39, p49 (a group of hepatic cytokeratins C, D, and E) and p56. The identity of the precipitated antigens was further confirmed by two-dimensional polyacrylamide gel electrophoresis. Only the Novikoff hepatoma poly(A)+ RNA contained translatable mRNA coding for the p39 cytokeratin while the p49 and p56 cytokeratins were translated from both the normal rat liver and Novikoff hepatoma poly(A)+ RNAs. Immunoprecipitations employing monoclonal antibody specific for p39 also recovered significant quantities of p56 and 49K cytokeratins, presumably due to oligomeric associations of these proteins with p39 immediately after in vitro synthesis. Similar results were observed after experiments with anti-p56 monoclonal antibody in which p39, not reactive with this antibody, was recovered in immunoprecipitates. Overall, the two-dimensional gel fluorograms of cytokeratins synthesized in vitro from NAH or liver poly(A)+ RNA are quite similar to isolated antigenic and cytokeratin profiles reported previously. These results suggest that overt posttranslational processing is not likely responsible for the diversity of cytokeratins observed in the liver.

ABSTRACTHepatitis G virus (HGV or GB-C virus) is a newly described virus that is closely related to hepatitis C virus (HCV). Based on sequence analysis and by evaluation of translational initiation codon preferences utilized during in vitro translation, HGV appears to have a truncated or absent core protein at the amino terminus of the HGV polyprotein. Consequently, the biophysical properties of HGV may be very different from those of HCV. To characterize HGV particle types, we evaluated plasma from chronically infected individuals with and without concomitant HCV infection by using sucrose gradient centrifugation, isopycnic banding in cesium chloride, and saline density flotation centrifugation. Similar to HCV, HGV particles included an extremely-low-density virion particle (1.07 to 1.09 g/ml) and a nucleocapsid of ~1.18 g/ml. One major difference between the particle types was that HGV was consistently more stable in cesium chloride than HCV. Plasma samples from chronically HGV-infected individuals and controls were assessed by a synthetic peptide-based immunoassay to determine if they contained HGV antibody specific for a conserved region in the coding region upstream of the E1 protein. Chronically HGV-infected individuals contained antibody to the HGV core protein peptide, whereas no binding to a hepatitis A virus peptide control was observed. Competitive inhibition of binding to the HGV peptide confirmed the specificity of the assay. These data indicate that HGV has a nucleocapsid and that at least part of the putative core region of HGV is expressed in vivo.

Hepatic encephalopathy most commonly occurs in patients with cirrhosis and end-stage liver disease, however, the disorder can also occur in the presence of intrahepatic or extrahepatic shunts when the intrahepatic circulation is effectively bypassed. The majority of extrahepatic shunts described to date develop between a mesenteric vein and inferior vena cava. Herein we report a novel case of a superior mesenteric vein to left internal iliac vein shunt that led to hepatic encephalopathy in a 57-year-old woman with no apparent underlying liver disorder. The patient presented with confusion, disorientation, and hyperammonemia. Workup for parenchymal liver disease was negative and liver biopsy findings did not show significant liver disease. Magnetic resonance imaging revealed a serpiginous 1-cm-wide shunt that diverted superior mesenteric vein blood from the portal confluence to the left internal iliac vein. Surgical closure of the shunt led to marked improvement of the patient with the resolution of hepatic encephalopathy. This report is the first description of a portosystemic shunt, likely congenital, linking these 2 vessels resulting in clinically significant hepatic encephalopathy. The findings emphasize that abdominal and pelvic imaging should be considered in patients with signs of hepatic encephalopathy that have none to minimal hepatic disease.

Previous experiments using a cationic surfactant to detect hepatitis C virus (HCV) RNA in whole blood (WB) suggested that WB was a more plentiful source of viral RNA than was plasma. The relative HCV RNA titers in WB, plasma, peripheral blood mononuclear cells (PBMC), neutrophils, and red blood cells (RBC)/platelets from 10 patients with chronic HCV infection were compared. WB contained significantly more HCV RNA than plasma, which contained more HCV RNA than PBMC, neutrophils, or RBC/platelets (P < .001). To determine if this increased sensitivity was clinically relevant, results of WB and plasma HCV RNA assays were compared with commercial quantitative and qualitative plasma HCV RNA assay results obtained for patients receiving interferon therapy. WB was significantly more sensitive than commercial plasma reverse transcription - polymerase chain reaction for detecting HCV RNA (P < .005). These data indicate that a significant proportion of HCV RNA in peripheral blood is not identified by standard plasma RNA detection methods.

Reverse transcription-polymerase chain reaction was used to identify hepatitis C virus (HCV) RNA in peripheral whole blood (WB) and plasma samples from 15 patients with chronic, unexplained hepatitis. These patients were serologically negative for hepatitis A, B, and C and were classified as having chronic non-A, non-B, non-C hepatitis (NANBNC). HCV RNA was repeatedly detected in WB samples from 10 (67%). In contrast, plasma samples from only 5 were intermittently positive. Statistically, HCV RNA detection in WB was significantly more sensitive than in plasma. Nucleic acid hybridization and HCV genotypic analysis confirmed the specificity of the HCV RNA assay. Liver biopsies from these patients suggested histopathologic differences between HCV RNA-positive and -negative groups. These data demonstrate that HCV infection is present in patients with unexplained chronic hepatitis more frequently than previously believed. Additionally, WB HCV RNA detection is more sensitive than plasma assays in identifying antibody-negative HCV infection.