bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhanced expression of cytokine-induced neutrophil chemoattractant in rat hepatic allografts during acute rejection
Authors: Yamaguchi Y , Ichiguchi O , Matsumura F , Akizuki E , Matsuda T , Okabe K , Yamada S , Liang J , Mori K , Ogawa M
Published: July 2004

The kinetics of messenger RNA (mRNA) and protein levels of cytokine-induced neutrophil chemoattractant (CINC) in rat hepatic allografts during acute rejection were investigated. Infiltrating cells were identified by double immunostaining with anti-CINC and anti-macrophage monoclonal antibodies, ED1 and ED2. The serum CINC concentration in untreated hepatic allograft recipients increased significantly at a constant rate over time after transplantation. No significant increases in serum CINC concentrations were observed in hepatic isografts or allografts treated with the immunosuppressant FK506. The number of neutrophils in untreated hepatic allografts increased significantly at a constant rate. Conversely, neutrophil accumulation in isografts or allografts treated with FK506 was much less than in untreated hepaticallografts. Immunostaining revealed that in the portal areas, mononuclear cells infiltrating untreated allograft liver were mainly positive for CINC and that CINC+ cells represented a subpopulation (˜ 25%) of the ED1+ cells. On the other hand, in the sinusoidal areas CINC+ cells were scattered and mainly positive for ED2. Levels of CINC mRNA in liver tissues taken from untreated hepatic allografts increased after transplantation, peaked on day 5, and decreased thereafter. Hepatic allografts treated with FK506 or isografts showed much lower levels of CINC mRNA than untreated allografts. Allogeneic mixed lymphocyte reactions induced CINC production. The cellular source of CINC was mononuclear cells. CINC production in mixed lymphocyte reactions was inhibited in the presence of anti-tumor necrosis factor α (TNF-α) antibody. These results suggest that enhanced expression of CINC mRNA and prominent accumulation of neutrophils in the liver grafts are characteristic features of the immune response during acute rejection.
Targeting naproxen coupled to human serum albumin to nonparenchymal cells reduces endotoxin-induced mortality in rats with biliary cirrhosis
Authors: Albrecht C , Meijer D K , Lebbe C , Sagesser H , Melgert B N , Poelstra K , Reichen J
Published: July 2004

Endotoxin is thought to play a major role in cirrhotic liver disease. Cyclo-oxygenase inhibitors were shown to be partially protective against endotoxin but cannot be used in cirrhotic patients because of renal side-effects. We argued that administration of naproxen (NAP) linked to human serum albumin (HSA), which results in specific delivery of NAP to endothelial cells (EC) and Kupffer cells (KC) and exhibited hepatoprotective effects against lipopolysaccharide (LPS) in vitro, could protect cirrhotic rats from LPS toxicity while preserving renal function. The studies were performed in rats rendered cirrhotic by bile duct ligation (BDL); animals received LPS (Escherichia coli, 800 μg/kg) intravenously. Five groups were studied: LPS alone, rats pretreated with a conventional dose of NAP (50 mg/kg), NAP-HSA (22 mg/kg), NAP equimolar to NAP-HSA (1.5 mg/kg), or the HSA carrier. LPS induced significant mortality (55%); this was not affected by equimolar NAP (57%) but accentuated by conventional NAP (88%). In contrast, NAP-HSA provided significant protection (9%; P < .05). After conventional NAP treatment, significant renal toxicity was observed as evidenced by a marked reduction in sodium excretion (LPS vs. NAP-HSA vs. NAP [50 mg/kg] 33 ± 22 vs. 50 ± 39 vs. 4 ± 3 μmol/h; P < .05). Renal prostaglandin E2 (PGE2) excretion was reduced by NAP in all groups, but most markedly at the conventional dosage (LPS vs. NAP-HSA vs. NAP [50 mg/kg] 132 ± 115 vs. 39 ± 19 vs. 9 ± 8 ng/mL; P < .05). Successful targeting was evidenced by a significant hepatic enrichment of NAP in the NAP-HSA group compared with the equimolar untargeted group (30.16 ± 9.33 vs. 1.13 ± 1.95 nmol/g liver). Thus, targeting NAP to EC/KC results in improved survival, higher efficacy, and sparing of renal function in cirrhotic rats.
Cytoprotection by the osmolytes βine and taurine in ischemia- reoxygenation injury in the perfused rat liver
Authors: Wettstein M , Haussinger D
Published: July 2004

Medium osmolarity sensitively regulates Kupffer cell functions like phagocytosis and prostaglandin (PG) and cytokine production. Betaine and taurine, recently identified as osmolytes in liver cells, interfere with these effects. Because Kupffer cell activation is an important pathogenic mechanism in ischemia-reoxygenation injury, the influence of osmolarity and osmolytes was investigated in a rat liver perfusion model of warm ischemia. Livers were perfused with different medium osmolarities for 60 to 90 minutes in the absence of oxygen, followed by another 90 minutes of reoxygenation. Lactate dehydrogenase (LDH) leakage into the effluent perfusate during the hypoxic and the reoxygenation period was eight- to 10-fold higher with a medium osmolarity of 385 mosmol/L than in normo-osmolarity, and further decreased with hypo-osmolar perfusion buffer. Betaine and taurine addition to the perfusate in near physiological concentrations decreased hypoxia-reoxygenation-induced LDH leakage, aspartate transaminase (AST) leakage, and perfusion pressure increase in hyperosmolar and normo-osmolar perfusions. Stimulation of PGD2, PGE2, thromboxane B2 (TXB2), and tumor necrosis factor α (TNF-α) release, as well as induction of carbon uptake by the liver during reoxygenation, were suppressed by βine and taurine, pointing to an interference of these osmolytes with Kupffer cell function. In contrast, endothelial cell function as assessed by hyaluronic acid (HA) uptake was not influenced. It is concluded that warm ischemia- reoxygenation injury in rat liver is aggravated by hyperosmolarity and attenuated by hypo-osmolarity. The osmolytes βine and taurine have a protective effect, presumably by inhibition of Kupffer cell activation.
Progesterone metabolites and bile acids in serum of patients with intrahepatic cholestasis of pregnancy: Effect of ursodeoxycholic acid therapy
Authors: Meng L , Reyes H , Axelson M , Palma J , Hernandez I , Ribalta J , Sjovall J
Published: July 2004

The concentrations in serum of sulfated metabolites of progesterone are known to be elevated in patients with intrahepatic cholestasis of pregnancy (ICP). The profiles of these metabolites and conjugated bile acids were analyzed in serum from 11 patients with ICP before and during administration of ursodeoxycholic acid (UDCA) (8 patients) or placebo (3 patients). The clinical condition of 7 of the patients given UDCA improved markedly, and 1 patient given placebo had a spontaneous remission of the disease. The total concentration of conjugated bile acids in the 11 patients was 25 ± 6 micromol/L (mean ± SEM) and decreased to 6.3 ± 3.5 micromol/L in the 7 patients responding to treatment with UDCA. The level of 7α-hydroxy-4-cholesten-3-one was significantly lower (7.2 ± 2.2 ng/mL) in patients with ICP than in healthy pregnancy (18 ± 4.6 ng/mL) (P < .05). The concentrations of 5α-pregnane-3α,20α-diol mono- and disulfates decreased by 52% ± 7.9% and 68% ± 5.5%, respectively, in the patients responding to treatment. Similar decreases were observed for the mono- and disulfates of 5α-pregnane-3α,20α,21-triol and 5β-pregnane-3α,20α-diol. The disulfate of 5α-pregnane- 3β,20α-diol showed a smaller decrease, while glucuronidated steroids were not affected. The 3α-/3β-hydroxysteroid ratio and di-/monosulfate ratio decreased significantly during UDCA. The magnitudes of the changes of bile acid and steroid concentrations during UDCA were not correlated to each other. The results suggest that UDCA stimulates the biliary excretion of steroids with a 3α-sulfoxy group and disulfates. This effect seems to be independent of the effect on bile acid excretion, indicating the use of different transport proteins. The possibility of an effect of UDCA on the formation of the steroid sulfates cannot be excluded.
Modulation of circadian expression of D-site binding protein by the schedule of parenteral nutrition in rat liver
Authors: Ogawa A , Yano M , Tsujinaka T , Morimoto T , Morita S , Taniguchi M , Shiozaki H , Okamoto K , Sato S , Monden M
Published: July 2004

The aim of this study was to investigate the changes in the circadian rhythm of the expression of liver-specific genes caused by different schedules of parenteral nutrition (PN). Rats received PN continuously throughout the day or intermittently during the night or day for 7 days. They were examined for gene expression of D-site binding protein (DBP), albumin, and cytochrome P450 cholesterol 7α-hydroxylase (CYP7) in the liver. The nocturnal PN group showed circadian expression of DBP messenger RNA (mRNA) and protein with a peak at 10 PM, in the same manner as the control rats receiving normal chow feeding. However, the diurnal PN group showed inverted expression of DBP mRNA and protein with a peak at 10 AM. CYP7 mRNA levels exhibited good synchronization with the levels of DBP mRNA in all groups, whereas albumin mRNA levels did not show such synchronization. Gel mobility-shift assay disclosed that the binding activity of the nuclear extracts to the CYP7 gene promoter was changed by the PN schedule in accordance with the expression of CYP7 mRNA. The PN schedule modulates the circadian rhythm of DBP expression and may have an effect on hepatic bile acid formation through transcriptional regulation of the CYP7 gene.
Effect of cytochrome P450 induction on phosphorus metabolites and proton relaxation times measured by in vivo 31P-magnetic resonance spectroscopy and 1H-magnetic resonance relaxometry in human liver
Authors: Block W , Reichel C , Traber F , Skodra T , Lamerichs R , Kreft B , Spengler U , Sauerbruch T , Schild H
Published: July 2004

Experimental and clinical studies have led to the hypothesis that the phosphodiester signal obtained by 31P magnetic resonance (MR) spectroscopy may be a specific marker for the hepatic induction of oxidative metabolism (P450 induction) by phenobarbitone or ethanol. Systematic studies in humans are lacking. Therefore, we studied 10 volunteers who received rifampin (600 mg/d) for 6 days, resulting in a documented induction of oxidative metabolism as measured by an increase in urinary 6-β-hydroxycortisol output in all volunteers (P = .0004). 31P-MR spectroscopy and 1H-MR relaxometry were performed before and after hepatic P450 induction. As shown by 31P-MR spectroscopy, the median phosphomonoester concentration (PME) relative to nucleoside triphosphate (NTP) increased by 21% from 0.63 (range, 0.40-0.89) before induction to 0.76 (0.49-1.67) after induction (P ≤ .0451). The median level of phosphodiesters (PDE) relative to NTP increased by 28% from 4.82 (3.41-6.67) before induction to 6.18 (4.63-11.63) after induction (P = .0091). An increase in the level of inorganic phosphates (Pi) relative to NTP was observed, but changes were not significant. As shown by 1H-MR relaxometry, a nonsignificant trend of the liver parenchyma to shorter relaxation times was observed after P-450 induction. In conclusion, both PME/NTP and PDE/NTP ratios (measured by in vivo 31P-MR spectroscopy) increased significantly after hepatic induction with rifampin. Further clinical studies with 31P-MR spectroscopy must take into account the potential effects of P450- inducing agents.
An improved digitonin-collagenase perfusion technique for the isolation of periportal and perivenous hepatocytes from a single rat liver: Physiological implications for lobular heterogeneity
Authors: Tordjmann T , Berthon B , Lardeux B , Moreau A , Jacquemin E , Combettes L , Feldmann G , Claret M
Published: July 2004

Morphological and functional heterogeneity of hepatocytes according to their position in the liver lobule has been known for many years. The digitonin-collagenase perfusion technique is widely used to study hepatocyte heterogeneity and has yielded reliable data. However, with this procedure, periportal (PP) or perivenous (PV) hepatocytes are isolated from different livers, allowing only comparison between cell populations issued from two separate animals. To overcome this drawback, we have modified this technique by perfusing the two main rat liver lobes of a single animal in succession. The procedure involved alternate clamping of the median and the left lateral lobes, restricting digitonin infusion to one lobe via the portal vein, and to the other via the caudal vena cava. Lobe exclusion during digitonin perfusion, and zonal restriction of digitonin-induced damage, were monitored using macroscopic and histological controls. We compared our results with previous data on PP and PV hepatocytes issued from two different livers using the conventional digitonin-collagenase perfusion technique. First, we found that the cellular sensitivity to angiotensin II, a calcium-mobilizing agonist, was 60% to 80% higher in PV than in PP hepatocytes, whereas, previously, no difference had been recorded. Second, we found that albumin messenger RNAs (mRNAs) were 35% more abundant in PP than in PV hepatocytes, whereas, previously, larger differences had been reported. Our results show that PP and PV hepatocytes may be isolated from a single liver using an improved digitonin-collagenase perfusion technique. Furthermore, we suggest that zonal differences can be artificially masked or amplified when comparing PP and PV cell populations from two different livers, indicating that it is preferable to use a single liver for accurate zonal comparisons between hepatocytes.
Hepatic growth hormone receptor, insulin-like growth factor I, and insulin-like growth factor-binding protein messenger RNA expression in pediatric liver disease
Authors: Holt R I , Crossey P A , Jones J S , Baker A J , Portmann B , Miell J P
Published: July 2004

Major changes in serum levels of insulin-like growth factor I (IGF-I) and IGF-binding proteins (IGFBPs) occur in children with end-stage liver disease in association with changes in body composition. We hypothesized that these changes would be associated with changes in hepatic messenger RNA (mRNA) expression. Eleven children with end-stage extrahepatic biliary atresia and 11 controls (liver donors) were studied. Serum samples were obtained from the children with biliary atresia immediately before orthotopic liver transplantation. Serum IGF- I, IGFBP-1, and IGFBP-2 levels were measured by radioimmunoassay, and IGFBP-3 by immunoradiometric assay. In both groups, growth hormone receptor mRNA expression was examined by quantitative reverse transcription-polymerase chain reaction, IGF-I mRNA expression by ribonuclease protection assay, and IGFBP-1 to -4 mRNA expression by Northern analysis. Growth hormone receptor and IGF-I mRNA levels were reduced 1.7-fold (P = .003) and 9.6-fold (P = .0001) in biliary atresia compared with levels in controls. Despite increased serum IGFBP-1 levels and reduced IGFBP-3 levels in biliary atresia, there was no change in either IGFBP-1 or IGFBP-3 mRNA expression. In contrast, serum levels and mRNA expression of IGFBP-2 were increased 1.6-fold (P = .003) and twofold (P = .0001), respectively, compared with controls. Gene expression did not correlate with liver dysfunction or body composition. Changes in growth hormone receptor and IGF-I mRNA expression may account for the reduction in serum IGF-I found in pediatric liver disease. In contrast, the marked alteration in circulating IGFBP levels was not accompanied by changes in hepatic IGFBP gene expression, suggesting that posttranslational mechanisms may be important.
Hepatic expression of the woodchuck hepatitis virus X-antigen during acute and chronic infection and detection of a woodchuck hepatitis virus X-antigen antibody response
Authors: Jacob J R , Ascenzi M A , Roneker C A , Toshkov I A , Cote P J , Gerin J L , Tennant B C
Published: July 2004

The expression and localization of the woodchuck hepatitis virus X-antigen (WHxAg) was examined and compared with other markers of a woodchuck hepatitis virus (WHV) infection using rabbit antisera generated against recombinant WHxAg produced in bacteria. Cellular fractionation studies showed that WHxAg was localized to the soluble and cytoskeletal fractions of the cell when assayed by immunoprecipitation of [35S]-met-cys labeled extracts derived from primary cultures of acute WHV-infected hepatocytes. Immunohistochemical examination of liver from chronic WHV-infected animals showed WHV core antigen (WHcAg) and WHxAg expression in non-neoplastic tissue. The WHxAg was found localized to the cytoplasm of infected cells, similar to WHcAg. WHxAg expression was diminished in the foci of altered hepatocytes and in hepatocellular adenomas but was found in only 1 of 11 hepatocellular carcinomas (HCC). Hepatic biopsies from woodchucks experimentally inoculated with WHV were examined during the acute phase of infection and during convalescence for WHcAg and WHxAg expression by immunohistochemistry. Concurrent expression of WHcAg and WHxAg was observed during the viremic phase of infection. The two antigens exhibited similar localization to the cell cytoplasm, similar distribution within the liver lobule, and similar patterns of clearance during convalescence. An immune response to WHxAg was documented in some woodchucks following acute WHV infection. These studies further define the woodchuck model of HBV infection and should allow for the investigation of the role of hepadnaviral X-antigen expression in the pathogenesis of chronic hepatitis and HCC.
A randomized, controlled trial of a 24-month course of interferon alfa 2b in patients with chronic hepatitis B who had hepatitis B virus DNA without hepatitis B e antigen in serum
Authors: Lampertico P , Del Ninno E , Manzin A , Donato M F , Rumi M G , Lunghi G , Morabito A , Clementi M , Colombo M
Published: July 2004

Short-term interferon treatment of serum hepatitis B e antigen (HBeAg)-negative carriers with serum hepatitis B virus (HBV) DNA and histological features of chronic hepatitis B has been largely unsuccessful. In a pilot study of long-term treatment, 42 such patients were randomly assigned to 6 million units of interferon alfa 2b (IFN-α2b) three times per week for 24 consecutive months (n = 21, 4 with cirrhosis) or to no therapy (n = 21, 3 with cirrhosis). Five patients (24%) discontinued therapy because of treatment-related adverse reactions. Serum levels of alanine transaminase (ALT) became persistently normal and HBV DNA undetectable by dot-blot assay in 8 patients receiving interferon and in 2 untreated controls (38% vs. 10%; P = .03). Hepatitis flare-ups disappeared in 17 patients during therapy compared with 6 controls (81% vs. 29%; P < .001). During a median period of 22 months after interferon was stopped, 2 treated patients (10%) lost serum hepatitis B surface antigen (HBsAg) and seroconverted to antibodies to hepatitis B surface antigen (anti-HBs). Serum ALT remained persistently normal and HBV DNA undetectable by dot-blot assay in 6 initial responders and 1 initial nonresponder, compared with none of the 21 untreated controls (sustained response: 33% vs. 0; P < .001). Comparative analysis of pre- and posttreatment liver biopsies showed that mean Knodell scores dropped in the treated group (10.3 to 5.3; P = .01), but not in the untreated group (9.3 to 9.8; not significant). In conclusion, a 24-month course of treatment with 6 MU IFN-α2b was well tolerated by most patients, led to sustained suppression of HBV in one third, and attenuated hepatitis in 81% of patients.
Humoral immune response to the E2 protein of hepatitis G virus is associated with long-term recovery from infection and reveals a high frequency of hepatitis G virus exposure among healthy blood donors
Authors: Tacke M , Schmolke S , Schlueter V , Sauleda S , Esteban J I , Tanaka E , Kiyosawa K , Alter H J , Schmitt U , Hess G , Ofenloch-Haehnle B , Engel A M
Published: July 2004

The second envelope protein (E2) of the hepatitis G virus (HGV) was expressed in Chinese hamster ovary (CHO) cells and showed a molecular weight of approximately 60 to 70 kd, with 15 to 25 kd of the size contributed by N-linked glycosylation. An enzyme-linked immunosorbent assay (ELISA) using HGV-E2 was developed to test for antibodies to this protein (anti-E2) in human sera. High sensitivity was achieved by developing monoclonal antibodies (mAbs) to HGV-E2, which were used as capture antibodies in the ELISA. Our studies revealed that 16% of healthy Spanish blood donors were exposed to HGV, indicating that additional routes of viral transmission besides parenteral exposure might exist. An even higher prevalence of exposure to HGV (52%-73%) was found in several groups at risk of parenteral exposure to infectious agents, i.e., intravenous drug users, transfusion history, hemophiliacs, and hepatitis C virus (HCV)-positive patients. Most anti-E2-positive patients were HGV-RNA-negative and vice versa, indicating an inverse correlation of these two viral markers. A panel of 16 posttransfusion patients followed for up to 16 years revealed that patients who develop an anti-E2 response become HGV-RNA-negative, while patients who do not develop anti-E2 are persistently infected. Immunity to HGV seems to be long-lasting, because circulating antibody to E2 could still be detected 14 years after seroconversion. Sequence comparisons showed that E2 is highly conserved among isolates collected worldwide, indicating that immune escape variants are not common in HGV infections. This reflects on a molecular level why HGV infections usually are cleared spontaneously by the host. However, possible mechanisms of HGV persistence, as found in some patients, remain to be elucidated.
Histological and clinical outcome after liver transplantation for hepatitis C
Authors: Shuhart M C , Bronner M P , Gretch D R , Thomassen L V , Wartelle C F , Tateyama H , Emerson S S , Perkins J D , Carithers R L
Published: July 2004

Hepatitis frequently recurs after liver transplantation for hepatitis C. However, the histological progression of disease, predictors of recurrence and disease severity, and patient survival remain uncertain. Fifty-five patients with cirrhosis caused by chronic hepatitis C underwent liver transplantation between January 1990 and December 1993. Hepatitis C genotype was determined, and liver biopsies were performed at frequent intervals posttransplantation. The median follow-up time was 40.4 months. The cumulative rate of survival was no different in liver transplant recipients for hepatitis C than in liver transplant recipients for other chronic liver diseases (P = .62). Histological recurrent hepatitis C developed in 33 of 50 patients assessable for disease recurrence; the median recurrence-free survival time was 13.4 months. Histological activity and stage were mild in most cases. Only 2 patients developed cirrhosis, and no patient required a second transplantation for recurrent disease. Patients with acute cellular rejection had a shorter recurrence-free survival (P = .0141). In patients with recurrent hepatitis, rejection also was correlated with increased histological grade 2 years after transplantation (P = .0061). Recurrence-free survival was decreased in patients infected with genotype 1 (1a and 1b combined) compared with genotypes 2 and 3 combined (P = .02), whereas there was no difference between genotypes 1a and 1b (P > .80). Only patients infected with genotype 1a or 1b developed bridging fibrosis or cirrhosis. In addition, patients who had an early recurrence had a greater risk of progressing to bridging fibrosis or cirrhosis (hazard ratio, 5.1; P = .0473). In our experience, recurrent hepatitis C after liver transplantation in most cases is mild and survival is unaffected. Both acute cellular rejection and infection with genotype 1 are independent risk factors for reduced recurrence-free survival, and early recurrence is associated with a higher risk of disease progression.
The prevalence of surface antigen variants of hepatitis B virus in Papua New Guinea, South Africa, and Sardinia
Authors: Carman W F , Van Deursen F J , Mimms L T , Hardie D , Coppola R , Decker R , Sanders R
Published: July 2004

Three assays, one based on monoclonal antibodies and the others on polyclonal antibodies, were employed to detect hepatitis B surface antigen (HBsAg)-reactive samples in both vaccinated and unvaccinated populations in areas of the world where hepatitis B virus (HBV) is endemic. Any discordant sera were tested by polymerase chain reaction (PCR) to confirm current infection, and sequence data were obtained from the DNA coding for the major hydrophilic region (MHR) of HBsAg of those samples positive for PCR. In all countries studied, samples that reacted in one HBsAg assay but not another were found. In the most extreme case, about 5% of viremic sera in Papua New Guinea were nonreactive in the monoclonal HBsAg assay; 9 of the 13 PCR-positive samples had novel or once-described variants, or a variant out of its usual genotype context. In South Africa, samples with sequences of subtype ayw2 reacted poorly, particularly in the polyclonal assay. Two had novel variants. In Sardinia, antibody to hepatitis B core antigen (anti-HBc) was analyzed as a marker of infection. A significant proportion of anti-HBc-positive, but monoclonal HBsAg-negative, vaccinees and unvaccinated persons were found to be PCR positive, as were some individuals without any markers of hepatitis B virus infection. Five more novel variants were found in these groups. There are implications for the design of HBsAg assays, which may have to be modified according to local sequence variability. Not all discordant samples were explained by variants, indicating that assay sensitivity is fundamental to diagnostic efficacy. Overall, this study defined 16 novel variants and 2 new potential epitope clusters.
Substrate specificity of sinusoidal bile acid and organic anion uptake systems in rat and human liver
Authors: Meier P J , Eckhardt U , Schroeder A , Hagenbuch B , Stieger B
Published: July 2004

The Na+-dependent bile salt uptake systems Ntcp (rodents) and NTCP (human), and the Na+-independent organic anion transporters oatpl (rat) and OATP (human) mediate sinusoidal uptake of a variety of amphipathic organic compounds into hepatocytes. Their properties indicate that an overall hepatic clearance of albumin-bound compounds is mediated by a limited number of multispecific transporters with partially overlapping substrate specificities.
The hepatitis C virus: Overview
Authors: Purcell R
Published: July 2004

Our knowledge of hepatitis C virus (HCV) dates only from 1975, when non- A, non-B hepatitis was first recognized. It was not until 1989 that the genome of the virus was first cloned and sequenced, and expressed viral antigens used to develop serological assays for screening and diagnosis. HCV is in a separate genus of the virus family Flaviviridae. It is a spherical enveloped virus of approximately 50 nm in diameter. Its genome is a single-stranded linear RNA molecule of positive sense and consists of a 5′ noncoding region, a single large open reading frame, and a 3′ noncoding region. The open reading frame encodes at least three structural and six nonstructural proteins. The genome is characterized by significant genetic heterogeneity, based on which HCV isolates can be classified into six major genotypes and more than 50 subtypes. Even individual isolates of HCV are genetically heterogeneous (quasispecies diversity). Genetic heterogeneity of HCV is greatest in the amino-terminal end of the second envelope protein (hypervariable region 1). This region may represent a neutralization epitope that is under selective pressure from the host's humoral immune response. Infection with HCV proceeds to chronicity in more than 80% of cases, and even recovery does not protect against subsequent re-exposure to the virus. The development of a broadly protective vaccine against HCV will therefore require a better understanding of the molecular biology and immune response to this virus.
Hepatitis C: The clinical spectrum of disease
Authors: Hoofnagle J H
Published: July 2004

Hepatitis C virus (HCV) accounts for approximately 20% of cases of acute hepatitis, 70% of chronic hepatitis, and 30% of end-stage liver disease in the United States. The acute infection has an incubation period of 7 weeks (range, 4-20 weeks) and is symptomatic and icteric in only one third of patients. Serum aminotransferase levels generally increase greater than 10-fold elevated and as symptoms and signs resolve decrease into the normal range. Antibody to HCV is usually but not always present at the time of onset of symptoms. HCV RNA appears in the serum early during the incubation period, increases in titer and peaks at the time of symptoms, and then disappears in resolving disease. Importantly, 85% of patients with acute HCV infection develop chronic infection. In these patients, HCV RNA remains present and in approximately two thirds of patients, aminotransferases remain elevated in the range of 1.5- to 10-fold the upper limit of normal. The course of chronic hepatitis C is variable. Probably fewer than 20% of patients have symptoms and they are usually intermittent, vague, and nonspecific, largely being malaise and easy fatiguability. A small percentage of patients develop extrahepatic manifestations of hepatitis C, including cryoglobulinemia and glomerulonephritis. It is estimated that 20% to 30% of patients with chronic hepatitis C develop cirrhosis, but the process is generally slow and insidious. Once cirrhosis develops, symptoms are more common and the signs of end-stage liver disease can appear with jaundice, weakness, wasting, and gastrointestinal bleeding. Patients with cirrhosis are also at risk for developing hepatocellular carcinoma. Thus, this important liver disease has protean manifestations but is often insidious and can lead to end- stage liver disease despite the presence of few symptoms and signs of illness.
Natural history of hepatitis C
Authors: Seeff L B
Published: July 2004

Approximately 85% of persons with acute hepatitis C develop chronic hepatitis as determined by persistently abnormal serum enzymes and/or viremia (hepatitis C virus [HCV] RNA). Both the acute and chronic illnesses are predominantly asymptomatic. For this reason and because the chronic illness runs an extremely protracted course, it has been difficult to accurately define the frequency and rate of progression to symptomatic or end-stage liver disease, specifically cirrhosis and hepatocellular carcinoma (HCC). Three evaluation strategies have been used. The first, prospective studies beginning from disease onset, have identified over 8 to 14 year follow-up periods that morbidity (symptoms, cirrhosis) and mortality (hepatic failure, HCC) are modest in frequency. The second, prospective studies of subjects with already established chronic liver disease, have demonstrated high rates of development of cirrhosis, HCC, and mortality over relatively short follow-up periods. The third, retrospective/prospective (nonconcurrent prospective) studies, has consisted of follow-up of recipients of HCV- contaminated immunoglobulin and of transfusion recipients from five enzyme-monitored transfusion studies of the early 1970s. The former study identified no mortality, trivial morbidity, and minimal cirrhosis 17 years after infection. The latter, involving hepatitis cases and matched nonhepatitis controls studied over a 20-year period, demonstrated no increase in all-cause but a slight increase in liver- related mortality. Clinically evident chronic liver disease was noted to be minimal among those in follow-up with biochemically defined chronic hepatitis whose biopsy specimens showed no cirrhosis, but common among those with histologically detected cirrhosis. More than 90% of subjects with an original diagnosis of transfusion-related hepatitis C have remained positive for antibody to HCV (anti-HCV), most with persistent viremia. Two thirds of the anti-HCV-positive individuals have biochemically defined chronic hepatitis, whereas one third have persistently normal enzymes. Taken together, available data suggest that in the first two decades after infection, mortality and morbidity are modest in frequency. Both can be expected to increase as the disease advances to the third and fourth decades after acute infection, especially among those with established cirrhosis. The outcome among those with chronic hepatitis but without cirrhosis remains to be determined.
Hepatitis C in asymptomatic blood donors
Authors: Alter H J , Conry-Cantilena C , Melpolder J , Tan D , Van Raden Mark , Herion D , Lau D , Hoofnagle J H
Published: July 2004

Among 248 asymptomatic blood donors positive for antibody to hepatitis C virus (anti-HCV) enrolled in a long-term prospective study, 86% had chronic HCV infection and 14% appeared to have recovered as assessed by serial determinations of serum alanine aminotransferase (ALT) levels and HCV RNA by polymerase chain reaction. Established parenteral risk factors for HCV transmission were identified in 75% of donors. In addition, there was a strong independent association between HCV positivity and cocaine snorting, suggesting that shared snorting devices may be a covert route of parenteral transmission. Ear piercing in males was also significantly associated with transmission. There was no evidence for sexual spread. Although the majority of HCV carriers had both biochemical and histological evidence of chronic viral hepatitis, the extent of liver injury was generally mild. Among a larger population of 280 HCV RNA-positive donors, 17% had repeatedly normal ALT levels, 45% had levels that did not exceed twice, and only 22% had levels that exceeded five times the upper limit of the normal range. Among 81 patients who underwent liver biopsy, only 13% had evidence of severe hepatitis (8%) or cirrhosis (5%), despite a duration of infection that generally exceeded 15 years. No severe histological lesions were observed in blood donors with chronic HCV infection who had repeatedly normal ALT levels. In both donors and blood recipients, the frequency of severe morbidity or mortality related to HCV infection was less than 10% during the first two decades of infection. Further long-term studies are required to see if the progression to severe outcomes continues to accrue at this slow pace or whether it accelerates during subsequent decades.
Diagnosis of hepatitis C
Authors: Lok A S , Gunaratnam N T
Published: July 2004

Currently, the second- and third-generation enzyme immunoassays (EIA-2 and EIA-3) for hepatitis C virus antibody (anti-HCV) are the most practical screening tests for the diagnosis of HCV infection. The need for and the choice of supplementary or confirmatory tests depend on the clinical setting and the likelihood of a true-positive EIA result. Detection of HCV RNA in serum by polymerase chain reaction (PCR) assay is the gold standard for the diagnosis of HCV infection. However, the lack of uniformity in current PCR assays has tarnished this standard. Confirmatory tests for the diagnosis of HCV infection are in general unnecessary in anti-HCV-positive patients who present with chronic liver disease. When indicated, the most appropriate test in this setting is a qualitative PCR assay for HCV RNA. Confirmatory tests should always be performed in anti-HCV-positive blood donors and individuals with normal aminotransferase levels. The most appropriate approach is to retest for anti-HCV using recombinant immunoblot assay (RIBA) and then test for HCV RNA using PCR assay in those who are RIBA positive or indeterminate. Liver histology is the gold standard in assessing severity of liver disease. Quantitative tests for serum HCV RNA levels do not help to determine the severity of liver disease. At the moment, HCV genotyping should be considered a research tool and not a part of the diagnostic work-up in clinical practice. The goals of treatment for chronic hepatitis C are sustained biochemical and virological response. Viral clearance should be determined by qualitative PCR assay. Quantifying serum HCV RNA level can help in predicting response to interferon treatment, but further studies using more standardized assays are needed to determine if these values can be used to select patients for treatment.
Epidemiology of hepatitis C
Authors: Alter M J
Published: July 2004

In the United States, the annual number of newly acquired acute hepatitis C virus (HCV) infections has declined from an estimated 180,000 in the mid 1980s to an estimated 28,000 in 1995. Approximately 25% to 30% of these infections are clinically apparent cases that are sufficiently symptomatic to gain medical attention. Deaths from fulminant hepatitis C are rare. The prevalence of antibody to HCV (anti- HCV) in the general population of the United States is 1.8%, corresponding to an estimated 3.9 million Americans infected with HCV, and an estimated 8,000 to 10,000 deaths each year result from HCV- associated chronic liver disease. HCV infection affects persons of all ages, but most acute cases of hepatitis C and the highest prevalence of anti-HCV are found among young adults. The highest proportion both of incident cases and prevalent infections is among whites, but the highest incidence and prevalence rates are among non-white racial/ethnic groups. In the past, transfusion of blood and blood products was an important source of HCV transmission, but currently, high-risk drug and sexual exposures account for most HCV transmission. Although the incidence of acute hepatitis C has declined, there is a large reservoir of chronically infected Americans who can serve as a source of transmission to others and who are at risk of the severe consequences of chronic liver disease.
Therapy of hepatitis C: Overview
Authors: Lindsay K L
Published: July 2004

Based on the first decade of research on α interferon in viral hepatitis, one can conclude that up to 40% of patients with compensated chronic hepatitis C and elevated alanine aminotransferase (ALT) levels will respond at least transiently to interferon. Four forms of α interferon have been evaluated in large numbers of patients with chronic hepatitis C: alfa-2b, alfa-2a, alfa-n1, and consensus interferon (CIFN). Responses are defined on the basis of biochemical (ALT) or virological (hepatitis C virus [HCV] RNA testing by polymerase chain reaction [PCR]) end points, and as end-of-treatment response (ETR) or sustained response (SR). Biochemical ETR rates to 6 months of therapy range from 35% to 50%, and SR rates 6 months after treatment from 8% to 21%. Although 6-month treatment courses are associated with a significant rate of relapse, 12 months of initial treatment and re- treatment regimens markedly improve the SR rate. Long-term follow-up evaluation in patients with an SR to interferon consistently show long- lasting and significant clinical, virological, and histological improvement. Finally, baseline factors that have been shown to be associated with SR to 6 months of treatment are not accurate enough to predict response. Therefore, the best treatment strategy is a therapeutic trial. Further studies of interferon therapy of hepatitis C are needed to define better virological end points useful in stopping therapy, to understand and better manage significant side effects of interferon, and to evaluate the histological effects of interferon in biochemical nonresponders. Also needed is a better understanding of the causes of resistance to interferon. Finally, newer therapeutic regimens such as the use of induction therapy and combination therapies with ribavirin, other antiviral agents, cytokines, and cytokine modifiers are of primary importance in eventually developing safe and effective means of treatment of hepatitis C.
Therapy of hepatitis C: Meta-analysis of interferon alfa-2b trials
Authors: Carithers R L , Emerson S S
Published: July 2004

We performed an independent meta-analysis of all available randomized clinical trials of interferon alfa-2b in patients with chronic hepatitis C. Articles published between 1986 and 1996 had to include previously untreated patients who were randomly allocated to therapy with at least 2 million units (MU) of interferon alfa-2b three times weekly for 24 weeks. A total of 32 trials met the inclusion criteria. Of these, 20 compared interferon-treated patients to placebo recipients or untreated patients and were used in the primary meta-analysis that compared rates of end-of-treatment and 6-month post-treatment sustained biochemical (normal alanine aminotransferase [ALT] levels) responses, end-of-treatment and 6-month sustained virological responses (absence of hepatitis C virus [HCV] RNA), and end-of-treatment histological responses in patients with paired biopsies. An additional 12 trials compared different doses, duration, or strategies of treatment. In comparison with no treatment, interferon alfa-2b therapy was associated with significant improvement in all end points measured. End-of- treatment biochemical responses were seen in 47% of treated patients compared with 4% of controls (odds ratio, 25.1; P < .0001). The biochemical responses were sustained for at least 6 months in 23% of treated patients compared with 2% of controls (odds ratio, 17.8; P < .0001). End-of-treatment virologic responses were observed in 29% of treated patients compared with 5% of controls (odds ratio, 9.4; P < .001) and 6-month sustained virologic responses were documented in 8% of treated patients compared with 1% of controls (odds ratio, 8.6; P < .001). Histological responses were recorded in 73% of treated patients compared with 38% of controls (odds ratio, 4.8; P < .0001). Extended therapy for 12 to 24 months resulted in significant improvement in 6- month sustained responses: 27% versus 14% (odds ratio, 2.9; P < .001). Higher dose therapy also resulted in modest increases in end-of- treatment (61% vs. 52%; odds ratio, 1.8; P < .02) and 6-month sustained responses (28% vs. 19%; odds ratio, 2.2; P < .01).
Therapy of hepatitis C: Interferon alfa-2a trials
Authors: Lee W M
Published: July 2004

Interferon alfa-2a resembles other recombinant α interferons in structure and pharmacology. Studies delineating its efficacy suggest that after 6 to 12 months of therapy, sustained biochemical responses occur in 4% to 49% of patients, providing adequate doses (> or = 3 million units three times weekly) are used. Overall, a dose-response curve is evident in regard to biochemical responses, decrease in histological scores for inflammation, and virological responses (percent negative serum hepatitis C virus [HCV] RNA) after treatment. Differences in response rates between studies probably reflect patient selection and particularly the percent of patients with established cirrhosis, because these patients respond less well than those with earlier histological stages of disease. A variety of regimens of interferon alfa-2a have been used, including use of higher doses, longer periods of treatment, induction using higher doses initially, and intermittent pulse therapy. Both longer periods of therapy and induction dosing show strong but not significant trends toward improvement in response rates, which reach significance when the two strategies are combined. Outcome is not significantly improved by escalating doses during therapy when inadequate responses are seen, or by pulse therapy. The side effect profile of interferon alfa-2a is similar to that of other interferons. Long-term follow-up studies have demonstrated that 90% of patients with a sustained biochemical response at 6 months after therapy maintain the response, and 95% remain negative for HCV RNA in serum. Challenges for the future include better delineation of the advantages of induction dosing, the optimal duration of therapy, and further understanding of the frequent discordance between HCV RNA data and aminotransferase levels. This latter finding suggests that use of both parameters is necessary to evaluate fully responses to therapy.
Therapy of hepatitis C: Alpha interferon and ribavirin
Authors: Reichard O , Schvarcz R , Weiland O
Published: July 2004

Ribavirin is a nucleoside analogue that has been evaluated as a therapy of chronic hepatitis C alone and in combination with α interferon. Ribavirin is well absorbed orally and is typically given in doses of 1,000 to 1,200 mg/d. Three randomized, placebo-controlled studies comprising more than 150 patients have shown that therapy with ribavirin alone for 24 to 48 weeks resulted in a significant reduction in serum alanine aminotransferase (ALT) levels during therapy. However, ribavirin therapy did not lead to a substantial reduction in hepatitis C virus (HCV) RNA levels; almost all patients remained viremic, and serum aminotransferase levels increased to pretreatment values when therapy was stopped. The most common adverse event was a moderate and reversible hemolysis during treatment that caused a decrease in hemoglobin by 10% to 20% of baseline levels. Combination therapy of ribavirin with α interferon has demonstrated promise both in pilot studies and a recently completed randomized controlled trial. Ribavirin in standard doses combined with α interferon in doses of 3 million units (MU) three times weekly for 6 months was found to significantly improve the sustained biochemical and virological response rates compared with interferon alone. Combination therapy offers a promise to become standard therapy for patients with nonsustained response to α interferon alone, because the majority of such patients achieve a durable response after treatment with combination therapy. However, nonresponders to α interferon alone rarely achieve a sustained beneficial response to combination treatment. For interferon-naive patients, combination therapy is superior to therapy with α interferon alone in achieving sustained biochemical and virological responses, but the combination demonstrates clear-cut superiority only in patients with unfavorable profiles for a response to interferon, in particular patients with high levels of HCV RNA. The optimal use and regimen of combination therapy awaits further investigation. New antiviral agents are still needed for the proportion of patients who do not respond to α interferon, even in combination with ribavirin.
Side effects of α interferon in chronic hepatitis C
Authors: Dusheiko G
Published: July 2004

Alpha interferons have been used widely to treat chronic hepatitis C virus infection. These include recombinant interferons, purified natural leukocyte, and lymphoblastoid interferons. Alpha interferon is administered by subcutaneous or intramuscular injection either daily or three times weekly for a period of 6 to as long as 24 months. A wide array of adverse effects of α interferon have been described. Several side effects such as fever, headache fatigue, arthralgias, and myalgias are common, especially with the initial injections. These early side effects of interferon are predictable and are encountered in the majority of patients. These may not require dose modification, but can be problematic for a significant proportion of patients. Other adverse events effects may require dose modification or even discontinuation of therapy in 2% to 10% of patients. Neuropsychiatric side effects such as depression and irritability can be most troublesome; their mechanisms are not well understood. Granulocytes, platelets, and red blood cell counts decrease during treatment, but the decreases are usually mild, although they can be dose limiting if cell counts are low initially. Interferon has important immunomodulatory properties, and treatment can induce autoimmune phenomena, the most frequent being autoimmune thyroiditis with either hypothyroidism or hyperthyroidism, especially in predisposed patients. Other autoimmune disease can be aggravated by interferon therapy. Severe and even life- threatening side effects of interferon occur in 0.1% to 1% of patients; these include thyroid, visual, auditory, renal, and cardiac impairment, and pulmonary interstitial fibrosis. Some of these side effects may be irreversible. Higher doses of interferon (above 5 million units three times weekly) cause higher rates of adverse events than standard doses. Contraindications to α interferon have been recognized.