bluuebunny/crossref_metadata_2025 huggingface dataset:
Liver Involvement in the Histiocytic Disorders of Childhood
Authors: Jaffe Ronald
Published: March 2004

The liver can be involved directly, by infiltration, and indirectly—by remote effects—in the histiocytoses of childhood. Langerhans cell disease, the most well recognized of these, infiltrates the liver directly but has a remarkable selectivity for the bile ducts. Early involvement is by Langerhans cell histiocytosis (LCH) infiltration leading to a sclerosing cholangitis and, eventually, biliary cirrhosis. Gamma glutamyl transpeptidase is a sensitive indicator of liver infiltration in a child with LCH. The indirect effects on the liver of LCH elsewhere in the body are mediated through an accompanying macrophage activation syndrome that is most likely responsible for hepatomegaly and hypoalbuminemia but without direct infiltration. These indirect effects are completely reversible. Juvenile xanthogranuloma/xanthoma disseminatum, a related dendritic cell disorder that can have systemic manifestations, has a strikingly different pattern, with a predominantly portal infiltrate spilling over into the adjacent lobule but sparing the biliary tree. The biology of the liver lesions is not clear but regression has been documented. Myeloproliferative disorders and myeloid leukemias can express CD1a and/or S100 protein, mimicking LCH but distinguished by their sinusoidal pattern. The primary macrophage histiocytoses such as the familial hemophagocytic syndromes can lead to severe liver damage. Although a portal lymphohistiocytic infiltrate is most characteristic, it is probably cytokine-mediated hepatocellular damage that can cause substantial functional impairment or even hepatic failure as a presenting feature. Liver involvement in other, more unusual histiocytic disorders, is also illustrated.
The histone methyltransferases Trithorax and Ash1 prevent transcriptional silencing by Polycomb group proteins
Authors: Klymenko Tetyana , Müller Jürg
Published: March 2004

Transcriptional on and off states of HOX genes and other developmental control genes are maintained by antagonistic regulators encoded by trithorax group (trxG) and Polycomb group (PcG) genes. The trxG proteins Ash1 and hTRX and the PcG repressor E(z) are histone methyltransferases (HMTases) that methylate distinct lysine residues in the N‐terminal tail of histone H3. trxG proteins are generally thought to function as activators of HOX genes, but how histone methylation by Ash1 and Trx promotes HOX gene transcription is not clear. Here, we show that in ash1 and trx mutants expression of HOX genes is lost within their normal expression domains, but we find that, contrary to expectation, this expression is restored in ash1 and trx mutants that also lack PcG gene function. Moreover, such trxG PcG double mutants show severe misexpression of HOX genes and, hence, ectopic activation of HOX genes caused by the removal of PcG gene function also occurs in the absence of ash1 and trx function. Together, these results suggest that the Ash1 and Trx HMTases are not ‘coactivators’ required for transcriptional activation of HOX genes, but function specifically as anti‐repressors. We propose that histone methylation by Ash1 and Trx is required continuously throughout development to prevent inappropriate PcG silencing of HOX genes in cells in which they must stay transcriptionally active.
DNA double‐strand breaks, recombination and synapsis: the timing of meiosis differs in grasshoppers and flies
Authors: Viera Alberto , Santos Juan L , Page Jesús , Parra M Teresa , Calvente Adela , Cifuentes Marta , Gómez Rocío , Lira Renee , Suja José A , Rufas Julio S
Published: March 2004

The temporal and functional relationships between DNA events of meiotic recombination and synaptonemal complex formation are a matter of discussion within the meiotic field. To analyse this subject in grasshoppers, organisms that have been considered as models for meiotic studies for many years, we have studied the localization of phosphorylated histone H2AX (γ‐H2AX), which marks the sites of double‐strand breaks (DSBs), in combination with localization of cohesin SMC3 and recombinase Rad51. We show that the loss of γ‐H2AX staining is spatially and temporally linked to synapsis, and that in grasshoppers the initiation of recombination, produced as a consequence of DSB formation, precedes synapsis. This result supports the idea that grasshoppers display a pairing pathway that is not present in other insects such as Drosophila melanogaster, but is similar to those reported in yeast, mouse and Arabidopsis. In addition, we have observed the presence of γ‐H2AX in the X chromosome from zygotene to late pachytene, indicating that the function of H2AX phosphorylation during grasshopper spermatogenesis is not restricted to the formation of γ‐H2AX foci at DNA DSBs.
A new role for the mitotic RAD21/SCC1 cohesin in meiotic chromosome cohesion and segregation in the mouse
Authors: Xu Huiling , Beasley Matthew , Verschoor Sandra , Inselman Amy , Handel Mary Ann , McKay Michael J
Published: March 2004

The evolutionarily conserved cohesin complex is required for the establishment and maintenance of sister chromatid cohesion, in turn essential for proper chromosome segregation. RAD21/SCC1 is a regulatory subunit of the mitotic cohesin complex, as it links together all other subunits of the complex. The destruction of RAD21/SCC1 along chromosomal arms and later at centromeres results in the dissociation of the cohesin complex, facilitating chromosome segregation. Here, we report for the first time that mammalian RAD21/SCC1 associates with the axial/lateral elements of the synaptonemal complex along chromosome arms and on centromeres of mouse spermatocytes. Importantly, RAD21/SCC1 is lost from chromosome arms in late prophase I but persists on centromeres. The loss of centromeric RAD21/SCC1 coincides with the separation of sister chromatids at anaphase II. These findings support a role for mammalian RAD21/SCC1 in maintaining sister chromatid cohesion in meiosis.
Proliferation of hepatic lineage cells of normal C57BL and interleukin-6 knockout mice after cocaine-induced periportal injury
Authors: Rosenberg David , Ilic Zoran , Yin Li , Sell Stewart
Published: March 2004

The cellular response to periportal liver injury, induced by phenobarbital feeding and cocaine injection, is used to compare the restitutive proliferation of hepatocytes, cholangiocytes, and oval cells in the livers of normal control to those of interleukin-6 (IL-6) knockout mice. After this injury hepatocytes in noninjured middle and central zones start to proliferate first, followed by proliferation of cholangiocytes and intraportal oval cells. Proliferation of all cell types peaks at 2 days, but oval cells continue to proliferate and differentiate through days 4 and 6 as they reconstitute the necrotic zone. By day 10, the injured zone is completely repaired, and no dividing cells remain. During the first 3 to 4 days after injury, the number of proliferating hepatocytes, cholangiocytes, and sinusoidal cells is lower in IL-6 knockout mice than in normal mice, whereas the number of dividing oval cells is higher. However, overall repair of the injury is accomplished in the same time period in both groups. During repair of the periportal zone, oval cells acquire differentiation markers of hepatocytes as they cross the zone of injury. In conclusion, the phenobarbital/cocaine injury model is useful to study restitutive proliferation of mouse liver cell lineages. The proliferative response in IL-6 knockout mice shows that IL-6 is not required for proliferation of liver cells; timely repair of liver injury occurs in both normal and IL-6 knockout mice. Increased proliferation of oval cells in IL-6 knockout mice may compensate for the lower proliferation of other liver cell types.
Implication of Bcl-2 family genes in basal and d-amphetamine-induced apoptosis in preneoplastic and neoplastic rat liver lesions
Authors: De Miglio Maria R. , Muroni Maria R. , Simile Maria M. , Calvisi Diego F. , Tolu Paola , Deiana Luca , Carru Angelo , Bonelli Gabriella , Feo Francesco , Pascale Rosa M.
Published: March 2004

Molecular mechanisms of basal and D-amphetamine (AMPH)-induced apoptosis were studied in rat liver nodules, 12 (N12) and 30 (N30) weeks after initiation, and in hepatocellular carcinoma (HCC) induced by diethylnitrosamine in rats subjected to resistant hepatocyte model. Basal apoptosis in hematoxylin/eosin- and propidium iodide-stained sections was higher in nodules and HCC than in normal livers. It sharply increased in all tissues 4 hours after AMPH treatment (10 mg/kg), and declined to basal levels at 8 to 12 hours in liver and N12, but remained high up to 18 hours in N30 and HCC. c-myc, Tgf-α, p53, and Bcl-XS
messenger RNA (mRNA) levels were higher, and Bcl-2 mRNA was lower in N12 and/or N30 and HCC than in normal liver. Four hours after AMPH injection, increase in c-myc and decreases in Bcl-2and Bcl-XL
mRNAs occurred in all tissues, whereas p53, Bax, and Bcl-XS
mRNAs increased in N30 and HCC. These changes disappeared in liver and N12 at 18 hours, but persisted in N30 and HCC. c-Myc, P53, Bcl-2, and Bax proteins in normal liver and HCC ± AMPH showed similar patterns. Tgf-β1, Tgf-β-RIII, CD95, and CD95L mRNA levels underwent slight or no changes in any tissue ± AMPH. Basal Hsp27 expression was high in nodules and HCC, and was stimulated by AMPH in liver and N12, but not in N30 and HCC. These data suggest a role of dysregulation of Bcl-2family genes and, at least in atypical lesions, of p53overexpression, in basal and AMPH-induced apoptosis in nodules and HCCs. Hsp27 does not appear to sufficiently protect atypical lesions against apoptosis.
Hepatocyte transplantation in rats with decompensated cirrhosis
Authors: Kobayashi Naoya , Ito Masahiro , Nakamura Junta , Cai Jin , Gao Chen , Hammel James M. , Fox Ira J.
Published: March 2004

Hepatocyte transplantation improves the survival of laboratory animals with experimentally induced acute liver failure and the physiological abnormalities associated with liver-based metabolic deficiencies. The role of hepatocyte transplantation in treating decompensated liver cirrhosis, however, has not been studied in depth. To address this issue, cirrhosis was induced using phenobarbital and carbon tetrachloride (CCL4) and animals were studied only when evidence of liver failure did not improve when CCL4 was held for 4 weeks. Animals received intrasplenic transplantation of syngeneic rat hepatocytes (G1); intraperitoneal transplantation of syngeneic rat hepatocytes (G2); intraperitoneal transplantation of a cellular homogenate of syngeneic rat hepatocytes (G3); intraperitoneal transplantation of syngeneic rat bone marrow cells (G4); or intrasplenic injection of Dulbecco’s modified Eagle medium (DMEM) (G5). After transplantation, body weight and serum albumin levels deteriorated over time in all control (G2-G5) animals but did not deteriorate in animals receiving intrasplenic hepatocyte transplantation (G1) (P < .01). Prothrombin time (PT), total bilirubin, serum ammonia, and hepatic encephalopathy score were also significantly improved toward normal in animals receiving intrasplenic hepatocyte transplantation (P < .01). More importantly, survival was prolonged after a single infusion of hepatocytes and a second infusion prolonged survival from 15 to 128 days (P < .01). Thus, hepatocyte transplantation can improve liver function and prolong the survival of rats with irreversible, decompensated cirrhosis and may be useful in the treatment of cirrhosis in humans.
Human liver class I alcohol dehydrogenase γγ isozyme: the sole cytosolic 3β-hydroxysteroid dehydrogenase of iso bile acids
Authors: Marschall Hanns-Ulrich , Oppermann Udo C.I. , Svensson Stefan , Nordling Erik , Persson Bengt , Höög Jan-Olov , Jörnvall Hans
Published: March 2004

3β-Hydroxy (iso) bile acids are formed during enterohepatic circulation from 3α-hydroxy bile acids and constitute normal compounds in plasma but are virtually absent in bile. Isoursodeoxycholic acid (isoUDCA) is a major metabolite of UDCA. In a recent study it was found that after administration of isoUDCA, UDCA became the major acid in bile. Thus, epimerization of the 3β-hydroxy to a 3α-hydroxy group, catalyzed by 3β-hydroxysteroid dehydrogenases (HSD) and 3-oxo-reductases must occur. The present study aims to characterize the human liver bile acid 3β-HSD. Human liver cytosol and recombinant alcohol dehydrogenase (ADH) ββ and γγ isozymes were subjected to native polyacrylamide gel electrophoresis (PAGE) and isoelectric focusing. Activity staining with oxidized nicotinamide adenine dinucleotide (NAD+) or oxidized nicotinamide adenine dinucleotide phosphate (NADP+) as cofactors and various iso bile acids as substrates was used to screen for 3β-HSD activity. Reaction products were identified and quantified by gas chromotography/mass spectrometry (GC/MS). Computer-assisted substrate docking of isoUDCA to the active site of a 3-dimensional model of human class I γγ ADH was performed. ADH γγ isozyme was identified as the iso bile acid 3β-HSD present in human liver cytosol, with NAD+ as a cofactor. Values for kcat
/Km were in the rank order isodeoxycholic acid (isoDCA), isochenodeoxycholic acid (isoCDCA), isoUDCA, and isolithocholic acid (isoLCA) (0.10, 0.09, 0.08, and 0.05 min-1 × μmol/L-1, respectively). IsoUDCA fits as substrate to the 3-dimensional model of the active-site of ADH γγ. ADH γγ isozyme was defined as the only bile acid 3β-HSD in human liver cytosol. Hydroxysteroid dehydrogenases are candidates for the binding and transport of 3α-hydroxy bile acids. We assume that ADH γγ isozyme is involved in cytosolic bile acid binding and transport processes as well.
Hemolytic anemia induced by ribavirin therapy in patients with chronic hepatitis C virus infection: Role of membrane oxidative damage
Authors: De Franceschi Lucia , Fattovich Giovanna , Turrini Franco , Ayi Kodjo , Brugnara Carlo , Manzato Franco , Noventa Franco , Stanzial Anna Maria , Solero Pietro , Corrocher Roberto
Published: March 2004

The antiviral drug ribavirin (RBV) is widely used in combination with interferon (IFN) in the treatment of chronic hepatitis C virus (HCV) infection. A major side effect of RBV is a reversible hemolytic anemia. We have evaluated the in vitro effects of RBV on erythrocyte adenosine triphosphate (ATP) content and on hexosemonophosphate shunt (HMS). The ATP levels were significantly decreased in the presence of RBV and the HMS was increased, suggesting the presence of red cell susceptibility to oxidation. In vivo, we have studied the hematologic effects of treatment with RBV alone or in combination with IFN in 11 patients with chronic hepatitis C: 6 were treated with RBV (1,000-1,200 mg/d) and 5 were treated with a combination of RBV and IFN (5 million U thrice weekly). Patients were studied at semi-monthly intervals from 0 to day 60 of therapy. Both treatments were associated with a significant reduction in hemoglobin levels (steady state level at day 45) and a marked increase in absolute reticulocyte counts. Erythrocyte Na-K pump activity was significantly diminished, whereas K-Cl cotransport and its dithiotreitol-sensitive fraction, malondialdehyde and methemoglobin levels were significantly increased. RBV-treated patients showed an increase in aggregated band 3, which was associated with a significantly increased binding of autologous antibodies and complement C3 fragments indicating an erithrophagocytic removal by reticuloendothelial system.
Deactivation of cultured human liver myofibroblasts by Trans -resveratrol, a grapevine-derived polyphenol
Authors: Godichaud Sandrine , Krisa Stéphanie , Couronné Baptiste , Dubuisson Liliane , Mérillon Jean-Michel , Desmoulière Alexis , Rosenbaum Jean
Published: March 2004

Liver myofibroblasts are major actors in the development of liver fibrosis and cancer progression. There is a large interest in drugs that might deactivate these cells. Many studies have shown that the grapevine-derived polyphenol,trans-resveratrol, and other stilbenes have therapeutic potential in some diseases. In this work, we have studied the effect of grapevine polyphenols on cultured human liver myofibroblasts. We have shown thattrans-resveratrol profoundly affects myofibroblast phenotype.Trans-resveratrol induced morphological modifications. It markedly reduced proliferation of myofibroblasts in a dose-dependent manner.Trans-resveratrol also decreased the expression of α smooth muscle actin (α-SMA) without affecting vimentin or β-cytoplasmic actin expression. It decreased myofibroblast migration in a monolayer wounding assay. We also showed thattrans-resveratrol inhibited the messenger RNA (mRNA) expression of type I collagen. Finally, it decreased the secretion of matrix metalloproteinase 2 (MMP-2). We conclude thattrans-resveratrol can deactivate human liver myofibroblasts. In the second part of this study, we have shown that neithertrans-piceid (a glycosylated analog) nortrans-piceatannol (a hydroxylated analog) reproducestrans-resveratrol effects on liver myofibroblasts. We finally show that, althoughtrans-resveratrol decreases the proliferation of skin fibroblast and vascular smooth muscle cells, it does not affect their expression of α-SMA, which indicates some cell specificity.
Functional significance of endothelin B receptors in mediating sinusoidal and extrasinusoidal effects of endothelins in the intact rat liver
Authors: Bauer Michael , Bauer Inge , Sonin Natalie V. , Kresge Nicole , Baveja Rajiv , Yokoyama Yukihiro , Harding David , Zhang Jian X. , Clemens Mark G.
Published: March 2004

Endothelins (ET) are important regulators of the hepatic microcirculation that act through different receptor subtypes. We investigated functional significance of ETB receptors in mediating microhemodynamic effects of ETs in normal and endotoxin (lipopolysaccharide [LPS])-primed rat liver. LPS priming (Escherichia coli O26:B6; 1 mg · kg−1) selectively increased ETB mRNA and led to a shift in available receptors to the ETB subtype. IRL 1620 (an ETB agonist) increased portal pressure in a dose-dependent manner, and the increase in ETB expression was associated with prolonged portal pressor response in isolated livers. However, lactate dehydrogenase (LDH) release was attenuated and sinusoidal blood flow was better maintained upon ETB stimulation in vivo. In isolated livers, portal constriction as well as release of LDH, were substantially increased in the presence of N
ω-nitro-l-arginine methyl ester (l-NAME), an inhibitor of nitric oxide synthase (NOS). In vivo microscopic assessment of sinusoidal perfusion during ETB stimulation revealed a disruption of the flow pattern including frequent reversal of the flow direction without significant sinusoid constriction. Sinusoidal flow decreased even further after discontinuation of IRL 1620. Both effects were mediated at extrasinusoidal sites that probably included postsinusoidal sites. However, after pretreatment with l-NAME, IRL 1620 evoked a significant sinusoidal constriction that colocalized with the body of the stellate cell. We propose that ETB1-induced NOS activity attenuates ETB2 (and presumably ETA)-mediated portal pressor response and stellate cell constriction. Transcriptional activation of the ETB gene may have a permissive effect on liver blood flow and protect against hepatocellular damage under pathophysiological conditions associated with endotoxemia.
Tumor necrosis factor α down-regulates expression of the α1(I) collagen gene in rat hepatic stellate cells through a p20C/EBPβ- and C/EBPδ-dependent mechanism
Authors: Iraburu María J. , Domínguez-Rosales José A. , Fontana Luis , Auster Anitra , García-Trevijano Elena R. , Covarrubias-Pinedo Amador , Rivas-Estilla Ana María , Greenwel Patricia , Rojkind Marcos
Published: March 2004

Tumor necrosis factor α (TNF-α) is one of the key cytokines of the acute phase response and of many inflammatory processes. This cytokine has several antifibrogenic actions and down-regulates the expression of the type I collagen genes and induces the expression of metalloproteinases. Because TNF-α directly antagonizes some fibrogenic actions of transforming growth factor β1 (TGF-β1), we considered it important to map the cis-acting regulatory element of the α1(I) collagen (col1a1) promoter involved in TNF-α responsiveness in hepatic stellate cells (HSC), to investigate the transcription factors that bind to it, and to establish possible mechanisms by which TNF-α down-regulates its expression. In this article, we show the presence of a functional TNF-α-responsive element (TaRE) in the −378 to −345 region of the col1a1 promoter. This element colocalizes with a previously reported TGF-β1-responsive element. We further demonstrate that TNF-α induces nuclear translocation and binding of transcriptional complexes containing p20C/EBPβ, p35C/EBPβ, and C/EBPδ to this sequence of the promoter. Transient overexpression of C/EBPδ or p20C/EBPβ, the natural dominant negative form of C/EBPβ in HSC, down-regulated activity of a CAT reporter vector driven by −412 to +110 of the col1a1 promoter. Taken together, these data suggest that the −378 to −340 region of the col1a1 promoter is the site of convergence of different stimuli that ultimately modulate col1a1 gene transcription.
Treatment of chronic woodchuck hepatitis virus infection in the eastern woodchuck ( marmota monax ) with nucleoside analogues is predictive of therapy for chronic hepatitis B virus infection in humans
Authors: Korba Brent E. , Cote Paul , Hornbuckle William , Tennant Bud C. , Gerin John L.
Published: March 2004

The woodchuck hepatitis virus (WHV) and its natural host, the Eastern woodchuck (Marmota monax), have been established as a model of hepatitis B virus (HBV)-induced disease. Several published studies have used this experimental animal model system to demonstrate potential antiviral therapies for chronic HBV infections. However, there has been little comparative information available on compounds used in clinical anti-HBV studies in WHV-infected woodchucks, thereby making interpretations of the potential relative effectiveness of new antiviral agents in humans more difficult. In this report, using a series of placebo-controlled studies, we compared the relative effectiveness of several nucleoside analogues that have been used in clinical trials for the treatment of chronic HBV infection against WHV replication in chronically infected woodchucks. Adenine-5′-arabinoside monophosphate (Ara-AMP [vidarabine]), ribavirin, (−)β-l -2′,3′-dideoxy-3′-thiacytidine (3TC [lamivudine]), and famciclovir (oral prodrug of penciclovir) induced depressions in viremia and intrahepatic WHV-DNA replication that were consistent with their relative effectiveness in anti-HBV human clinical trials. As observed in HBV-infected patients, 3′ azido-3′-deoxythymidine (AZT [zidovudine]) had no effect on WHV replication in these studies. These experimental results more firmly establish chronic WHV infection in woodchucks as an accurate and predictive model for antiviral therapies against chronic HBV infection in humans and provide a baseline for comparative antiviral effects of other experimental antiviral agents in the WHV/woodchuck model system.
ATP depletion in rat cholangiocytes leads to marked internalization of membrane proteins
Authors: Doctor Brian R. , Dahl Rolf H. , Salter Kelli D. , Fouassier Laura , Chen Jing , Fitz Gregory J.
Published: March 2004

Intrahepatic bile ducts (BD) are a critical target of injury in the postischemic liver. Decreased vascular perfusion causes characteristic changes in the morphology of the ductular epithelia including a loss of secondary membrane structures and a decrease in plasma membrane surface area. Using adenosine triphosphate (ATP) depletion of cultured normal rat cholangiocytes (NRC) to model ischemic ducts, the present studies examined the fate of apical membrane proteins to determine whether membrane recycling might contribute to rapid functional recovery. Apical proteins, including γ-glutamyl transpeptidase (GGT), Na+-glucose cotransporter (SGLT1), and apically biotinylated proteins, were not shed into the luminal space during ATP depletion. Instead, labeling of surface proteins after ATP depletion showed a significant decrease in GGT and SGLT1, consistent with membrane internalization. Similarly, z-axis confocal microscopy of biotinylated apical proteins also showed protein internalization. During ATP recovery, SGLT1 transport activity remained profoundly depressed even after 24 hours of recovery, indicating that the function of the internalized apical proteins is not rapidly recovered. These studies suggest that the membrane internalization in ATP-depleted cholangiocytes is a unidirectional process that contributes to prolonged functional deficits after restoration of normal cellular ATP levels. This sustained decrease in transport capacity may contribute to the development of ductular injury in postischemic livers.
Management of primary biliary cirrhosis
Authors: Heathcote Jenny E.
Published: March 2004

Primary biliary cirrhosis (PBC) is a presumed autoimmune disease of the liver, which predominantly affects women once over the age of 20 years. Most cases are diagnosed when asymptomatic (60%). The antimitochondrial antibody is present in serum in most, but not in all, patients with PBC. The disease generally progresses slowly but survival is less than an age- and gender-matched general population. The symptomatic patient may have fatigue, generalized pruritus, portal hypertension, osteoporosis, skin xanthomata, fat soluble vitamin deficiencies, and/or recurrent asymptomatic urinary tract infections. Many nonhepatic autoimmune diseases are found in association with PBC and may prompt initial presentation. To date, immunosuppressive therapy has not been shown to prolong survival in PBC. The hydrophilic bile acid, ursodeoxycholic acid (UDCA), has been shown when given in a dose of 13 to 15 mg/kg daily for up to 4 years to delay the time to liver transplantation or death. This therapy also causes a significant improvement of all the biochemical markers of cholestasis but has no beneficial effects on any of the symptoms or associated disorders. Treatment with UDCA does not obviate the need for liver transplantation. Therapies to prevent complications arising from malabsorption, portal hypertension, and/or osteoporosis are required as well. Good control of pruritus can be achieved in most patients. PBC is diagnosed with increasing frequency, but the agent(s) responsible for this slowly progressive destruction of the interlobular bile ducts remains elusive and hence a specific therapy remains unavailable.
Host genetic factors influence disease progression in chronic hepatitis C
Authors: Powell Elizabeth E. , Edwards-Smith Catherine J. , Hay John L. , Clouston Andrew D. , Crawford Darrell H. , Shorthouse Claudia , Purdie David M. , Jonsson Julie R.
Published: March 2004

Progressive hepatic fibrosis and cirrhosis develops in 20% to 30% of patients with chronic hepatitis C virus (HCV). We propose that host genetic factors influencing fibrogenesis may account for some of the variability in progression of this disease. In progressive fibrosis of other organs, particularly heart and kidney, production of the profibrogenic cytokine, transforming growth factor β1 (TGF-β1), may be enhanced by angiotensin II, the principal effector molecule of the renin-angiotensin system. The inheritance of polymorphisms in TGF-β1, interleukin 10 (IL-10), tumor necrosis factor α (TNF-α), and genes of the renin-angiotensin system was examined in 128 patients with chronic HCV. The influence of genotypes on the stage of hepatic fibrosis was tested after adjustment for potential confounders (age, gender, alcohol consumption, portal inflammation, and steatosis), which may have independent effects on histological severity. The stage of fibrosis was 0 in 30 (23.4%), 1 in 44 (34.4%), 2 in 27 (21.1%), and 3 or 4 in 27 (21.1%). A statistically significant relationship was seen between inheritance of high TGF-β1- and angiotensinogen (AT)-producing genotypes and the development of progressive hepatic fibrosis. This association persisted after correcting for potential confounders. Patients who inherited neither of the profibrogenic genotypes had no or only minimal fibrosis. Knowledge of these polymorphisms may have prognostic significance in patients with chronic HCV and may direct more aggressive therapy towards those patients with an increased risk of disease progression. The documentation of a significant relationship between AT genotype and fibrosis raises the novel suggestion that angiotensin II may be another mediator of extracellular matrix production in the liver.
Comprehensive allelotype study of hepatocellular carcinoma: Potential differences in pathways to hepatocellular carcinoma between hepatitis B virus-positive and -negative tumors
Authors: Okabe Hiroshi , Ikai Iwao , Matsuo Koichi , Satoh Seiji , Momoi Hirohito , Kamikawa Tatsuhiko , Katsura Nagato , Nishitai Ryuta , Takeyama Osamu , Fukumoto Manabu , Yamaoka Yoshio
Published: March 2004

To examine the role of the loss of heterozygosity (LOH) in hepatitis-related carcinogenesis, we performed a genome-wide scan of LOH in 44 tumors of hepatocellular carcinoma (HCC) using 216 microsatellite markers throughout all human chromosomes. A high frequency of LOH (>30% of informative cases) was observed at 33 loci on chromosome arms 4q, 6q, 8p, 8q, 9p, 9q, 13q, 16p, 16q, 17p, and 19p. LOH on 19p has not yet been reported, and that appears to be a new candidate in the search for tumor suppressor genes. High rates of LOH are correlated with hepatitis B virus (HBV) positivity, poorly differentiated tumors, vascular invasion, and intrahepatic metastasis (P < .0001). LOH on 13q and 16q occurred more frequently in HBV(+) patients (P < .0001), and LOH on 6q occurred more frequently in virus-negative patients (P < .001). The frequency of LOH on 4q and 13q was significantly lower in well-differentiated tumors than in moderately and poorly differentiated tumors (P < .01). In contrast, LOH on 6q was frequently detected in well-differentiated tumors compared with other histological subclasses (P < .001). Our results suggest that LOH on 6q may play an important role in the early stage of hepatocarcinogenesis in virus-negative patients, but different mechanisms might underlie the initial step to carcinogenesis in HBV(+) patients. LOH on 13q and 16q may play an essential role in the progression of HBV(+) tumors. Further studies of fine deletion mapping on chromosomes 13q and 16q are required to define the genomic segments on which putative tumor suppressor genes responsible for HBV(+) tumors exist.
Survivin promotes cell proliferation in human hepatocellular carcinoma
Authors: Ito Takeshi , Shiraki Katsuya , Sugimoto Kazushi , Yamanaka Takenari , Fujikawa Katsuhiko , Ito Masaaki , Takase Koujiro , Moriyama Masami , Kawano Hirokazu , Hayashida Midori , Nakano Takeshi , Suzuki Atsushi
Published: March 2004

Survivin is a recently described inhibitor of apoptosis. Because suppression of apoptosis is important for carcinogenesis and tumor growth, we investigated the expression and function of survivin in human hepatocellular carcinomas (HCCs). We have shown that 4 HCC cell lines and 7 out of 8 human HCC tissues expressed survivin messenger RNA (mRNA), whereas expression of survivin mRNA was not detected in normal liver and nontumor areas of these tissues using the reverse transcription polymerase chain reaction. Survivin was detected primarily in the nucleus by immunofluorescence staining of HCC cells. In addition, 14 of 20 (70%) HCC tissues showed positive nuclear staining for survivin, whereas nontumor tissues showed little detectable staining by immunohistochemistry. Survivin expression strongly correlated with the proliferation index but not significantly with the apoptosis index in HCC tissues. Therefore, we performed cell cycle analysis after survivin transfection and showed that overexpression of survivin resulted in a decrease in the G0 /G1 phase and an increase in the S phase in all 4 HCC cell lines. Furthermore, we have found that survivin interacted with cyclin-dependent kinase 4 (Cdk4) and overexpression of survivin released p21WAF1/Cip1 (p21) from Cdk4. From these results, we conclude that survivin promotes cell proliferation by interacting with Cdk4 and releasing p21 from Cdk4. This may play an important role in carcinogenesis and progression of human HCCs.
Population screening for hemochromatosis: A comparison of unbound iron-binding capacity, transferrin saturation, and C282Y genotyping in 5,211 voluntary blood donors
Authors: Adams Paul C. , Kertesz Ann E. , McLaren Christine E. , Barr Robert , Bamford Anthony , Chakrabarti Subrata
Published: March 2004

Early diagnosis and treatment of hemochromatosis is essential to prevent organ damage. Screening strategies to detect early hemochromatosis include testing for iron overload and/or genetic testing. Voluntary blood donors numbering 5,211 were screened with unbound iron-binding capacity (UIBC), transferrin saturation (TS), and genetic testing for the C282Y mutation of the HFE gene. The study found 16 C282Y homozygotes (1 in 327), 69 compound heterozygotes, 371 simple heterozygotes, and 4,755 normals. There were 5 men and 11 women homozygotes with a mean age of 42, range 28 to 57. Mean UIBC (24 ± 7 μmol/L) and TS (48% ± 17%) in homozygotes were significantly different from compound heterozygotes, simple heterozygotes, and normals (ANOVA). Only 3 homozygotes had an elevated serum ferritin. Family studies found an additional 4 iron-loaded homozygotes. Optimal thresholds were ≤28 μmol/L for UIBC and ≥46% for TS. Receiver operating characteristic (ROC) curve analysis showed an area under the curve for UIBC of 0.93 (0.85-1.0, 95% confidence interval), and for TS of 0.83 (0.7-0.95). Screening with UIBC to preselect those for genotyping is a cost-efficient strategy for population screening for hemochromatosis.
Ethanol potentiates tumor necrosis factor-α cytotoxicity in hepatoma cells and primary rat hepatocytes by promoting induction of the mitochondrial permeability transition
Authors: Pastorino John G. , Hoek Jan B.
Published: March 2004

In the present study, tumor necrosis factor-α (TNF-α) cytotoxicity is shown to be potentiated by ethanol exposure in vitroin the human hepatoma cell line, HepG2, and in rat primary hepatocytes. Exposure of HepG2 cells and primary hepatocytes for 48 hours to concentrations of ethanol ranging between 50 and 100 mmol/L significantly increased TNF-α cytotoxicity compared with cells treated with TNF-α alone. The cell killing was associated with, and dependent on, the development of the mitochondrial permeability transition (MPT). Two inhibitors of MPT pore opening, cyclosporin A and bongkrekic acid, prevented TNF-α cytotoxicity in the presence of ethanol. In addition to inhibiting cell death caused by TNF-α, blockade of MPT pore opening prevented mitochondrial depolarization, cytochrome c redistribution from the mitochondria to the cytosol, caspase 3 activation, and oligonucleosomal DNA fragmentation. Unlike the potentiation of TNF-α cytotoxicity by the translational inhibitor cycloheximide, ethanol promoted TNF-α-induced cell killing by a mechanism that was independent of caspase-8 activity. HepG2 cells overexpressing cytochrome-P4502E1 were even more sensitized by ethanol to induction of the MPT by TNF-α and the resultant cytotoxicity than wild-type HepG2 cells. In addition, primary hepatocytes isolated from chronically ethanol-fed rats showed enhanced susceptibility to TNF-α cytotoxicity compared with their isocalorically matched controls. Again as with the HepG2 cells, inhibiting MPT pore opening prevented the cytotoxicity of TNF-α in the primary hepatocytes isolated from ethanol-fed animals.
Induction by interleukin 6 of Gs-coupled prostaglandin E2 receptors in rat hepatocytes mediating a prostaglandin E2-dependent inhibition of the hepatocyte’s acute phase response
Authors: Fennekohl Alexandra , Lucas Maria , Püschel Gerhard P.
Published: March 2004

Prostanoids, that are released from nonparenchymal liver cells in response to proinflammatory stimuli, are involved in the regulation of hepatic functions during inflammation. They exert their effects on their target cells via heptahelical receptors in the plasma membrane. For the 5 prostanoids prostaglandin E2 (PGE2), prostaglandin F2α, prostaglandin D2(PGD2), prostacyclin, and thromboxane A2 there exist 8 receptors that are coupled to different heterotrimeric G proteins. These receptors are expressed differentially in the 4 principal liver cell types, i.e., hepatocytes, Kupffer cells, sinusoidal endothelial cells, and hepatic stellate cells. It was intriguing, that the messenger RNA (mRNA) of none of the Gs-coupled prostanoid receptors (DP-R, EP2-R, EP4-R, and IP-R) that can attenuate the inflammatory reaction were present in hepatocytes. The current study shows that the expression of the Gs-coupled prostanoid receptors EP2-R, EP4-R, and DP-R, but not the IP-R, was efficiently and rapidly up-regulated by treatment of hepatocytes in vitro or rats in vivo with the key acute phase cytokine interleukin 6 (IL-6). In IL-6-treated hepatocytes PGE2 in turn attenuated the IL-6-induced α2-macroglobulin formation via a cyclic adenosine monophosphate (cAMP)-dependent signal chain. The data indicate that an IL-6-mediated induction of the previously not expressed EP2-R and EP4-R on hepatocytes might establish a prostanoid-mediated feedback inhibition loop for the attenuation of the acute phase response.
Liver cell apoptosis in chronic hepatitis C correlates with histological but not biochemical activity or serum HCV-RNA levels
Authors: Calabrese Fiorella , Pontisso Patrizia , Pettenazzo Elena , Benvegnù Luisa , Vario Alessandro , Chemello Liliana , Alberti Alfredo , Valente Marialuisa
Published: March 2004

In hepatitis C virus (HCV) infection, mechanisms responsible for liver cell damage are still poorly understood and both necrosis and apoptosis may be operative. By using terminal deoxynucleotydil transferase-mediated d-UTP-biotin nick-end labeling (TUNEL) we have evaluated and quantified apoptosis in liver biopsy specimens from 61 patients with chronic hepatitis C. All patients had detectable apoptotic cells in the liver. Presence of increased apoptotic activity was confirmed in selected cases by electron microscopy and by DNA gel electrophoresis. The amount of liver cell apoptosis expressed as apoptotic index, ranged between 0.01% to 0.54% and showed a positive correlation with histological activity grading (P < .0005) and with the amount of infiltrating CD8-positive cells (P = .01). Apoptosis did not correlate with transaminase levels or with HCV load and genotype. These results support the concept that immune-mediated apoptosis may play a role in the pathogenesis of chronic hepatitis C and indicate that this type of reaction may occur in the absence of significant alanine transaminase (ALT) elevation, thus explaining the lack of correlation between biochemical activity and liver histological damage.
Chemotherapeutic Agents Augment TRAIL-Induced Apoptosis in Human Hepatocellular Carcinoma Cell Lines
Authors: Yamanaka Takenari , Shiraki Katsuya , Sugimoto Kazushi , Ito Takeshi , Fujikawa Katsuhiko , Ito Masaaki , Takase Koujiro , Moriyama Masami , Nakano Takeshi , Suzuki Atsushi
Published: March 2004

TNF-related apoptosis-inducing ligand (TRAIL) selectively induces apoptosis in various transformed cell lines but not in almost-normal tissues. It is regulated by 2 death receptors, TRAIL receptor 1 (TRAIL-R1) and TRAIL-R2, and 2 decoy receptors, TRAIL-R3 and TRAIL-R4. We investigated the expression of TRAIL-R- and TRAIL-induced apoptosis in human hepatocellular carcinomas (HCCs). TRAIL-R1, -R2, and -R4 were expressed in 6 HCC cell lines examined, but TRAIL-R3 was expressed in only 2 of the 6 cell lines. In addition, immunohistochemical results revealed a high and prevalent expression of TRAIL-R1 and -R2 in human HCC tissues. Despite the expression of TRAIL-R1 and -R2, all 6 HCC cell lines showed resistance to TRAIL-induced apoptosis with no relation to nuclear factor κ B (NF-κB) levels induced by TRAIL. TRAIL-induced death signal was inhibited with both decreased caspase-8 and caspase-3 activity. However, TRAIL induced significant apoptosis in the presence of a subtoxic level of actinomycin D, indicating that the TRAIL-induced apoptotic pathway is in place in these cell lines. In addition, we found that treatment with conventional chemotherapeutic agents, doxorubicin and camptothecin, dramatically augmented TRAIL-induced cytotoxicity in most of the HCC cell lines. Actinomycin D and camptothecin almost completely suppressed NF-κB induction by TRAIL, whereas doxorubicin had little effect. These results indicate that TRAIL, in combination with chemotherapeutic agents, may have therapeutic potential in the treatment of human HCC.
Effect of Bilirubin UDP Glucuronosyltransferase 1 Gene TATA Box Genotypes on Serum Bilirubin Concentrations in Chronic Liver Injuries
Authors: Doyama Hisashi , Okada Toshihide , Kobayashi Tomomi , Suzuki Ayako , Takeda Yasuo , Mabuchi Hiroshi
Published: March 2004

TATA box abnormality in the promoter region of the bilirubin UDP glucuronosyltransferase 1 gene has been reported to cause Gilbert’s syndrome in white subjects. It has also been reported that the majority of Japanese patients with Gilbert’s syndrome are heterozygous for Gly71Arg in the coding region of this gene. On the other hand, some patients with chronic hepatitis often show signs of unexpected hyperbilirubinemia. The aims of this study were to determine which of the genetic variations, TATA box genotype or codon 71 genotype, is most closely related to serum bilirubin concentrations, and whether the TATA box genotype has an effect on serum bilirubin concentrations in patients with hepatitis C-associated chronic liver diseases. In a sample of 300 individuals selected from among the general Japanese population, mean concentrations of total serum bilirubin differed significantly among TATA box genotypes, but not among codon 71 genotypes. Concentration of total serum bilirubin was significantly correlated with TATA box genotypes. In 211 patients with hepatitis C-associated chronic liver diseases, mean concentrations of total serum bilirubin also differed significantly among TATA box genotypes. In patients with chronic hepatitis C, concentration of total serum bilirubin was significantly correlated with TATA box genotypes. In summary, TATA box genotypes, but not codon 71 genotypes, are closely related to serum bilirubin concentrations. TATA box genotypes should therefore be considered when evaluating hepatic function by serum bilirubin concentrations in cases of hepatitis C-associated chronic liver diseases.
Melatonin Prevents Pigment Gallstone Formation Induced by Bile Duct Ligation in Guinea Pigs
Authors: Shiesh Shu-Chu , Chen Chiung-Yu , Lin Xi-Zhang , Liu Zher-Ann , Tsao Hui-Chen
Published: March 2004

Free radical-mediated oxidative stress has been implicated in the genesis of gallstone in vitro. This study was designed to examine the oxidative stress changes during pigment gallstone formation and to investigate whether melatonin (MLT) could act as a chemopreventive agent for cholelithiasis in a guinea pig model. The common bile duct of guinea pigs was ligated with or without MLT pretreatment. Animals were studied on day 7, 9, 12, and 14 after surgery. Stone and/or sludge developed in ligated guinea pigs without MLT. Fourier transform infrared spectra of the sludge showed the presence of calcium bilirubinate, whose peak height per milligram of sludge gradually increased with time after ligation. Total antioxidant activity (TAA) in bile of guinea pigs at day 14 after ligation reduced to one third of the level in sham-operated controls (P < .001). In addition, the bile of ligated guinea pigs had increased pH (P < .001), bile salts (P < .01), and malondialdehyde (MDA) (P < .05), compared to sham controls. Pretreatment of guinea pigs with MLT at a dose of 1,000 μg/kg significantly decreased the incidence of pigment gallstone formation at day 14 after ligation, as compared to no pretreatment (0/7 vs. 8/10). MLT also reverted the ligation-induced changes in biliary bile salts, pH, MDA, and TAA to control levels. These in vivo findings support a causative role of oxidative stress in the bile duct ligation-induced pigment gallstone formation. Antioxidants may prove useful in preventing pigment gallstone formation in humans.
Hepatocarcinogenesis in Female Mice With Mosaic Expression of Connexin32
Authors: Moennikes Oliver , Buchmann Albrecht , Willecke Klaus , Traub Otto , Schwarz Michael
Published: March 2004

Mice deficient for connexin32 (Cx32), the major gap junction forming protein in liver, are highly susceptible to hepatocarcinogenesis. Because the Cx32 gene is located on the X-chromosome, heterozygous females show mosaicism with respect to Cx32 expression; this enables their use in studying the effect of Cx32-deficiency in a mixed Cx32-plus/Cx32-minus environment in vivo. Female C3H/He mice (Cx32+/+) were crossed with Cx32-deficient C57BL/129Sv males (Cx32Y/-) to yield F1 females heterozygous with respect to Cx32 (Cx32+/−). Patches of hepatocytes were observed in normal liver that either expressed Cx32 or failed to express the protein. The mean fraction of Cx32-negative tissue in liver was about 60% and did not change significantly with age of mice. Neoplastic liver lesions, induced in weanling mice, were identified in serial liver sections by their deficiency in glucose-6-phosphatase staining. Parallel sections were used for immunohistochemical demonstration of Cx32 protein. Smaller lesions were either homogenously Cx32-negative or showed unchanged to slightly elevated levels of Cx32 protein. There were no major differences in number and size distribution between lesions of these 2 phenotypes. In addition, larger lesions were mostly Cx32-negative but often contained embedded patches of Cx32-positive cells. Staining for the proliferation-associated nuclear antigen Ki-67 did not reveal significant differences between Cx32-negative and Cx32-positive hepatocytes in Cx32-mosaic tumors. This suggests that expression of Cx32 within a subpopulation of tumor cells does not negatively regulate their growth nor does it seem to affect the proliferation of their directly neighboring Cx32-negative counterparts.
Quantitative evaluation of genomic instability as a possible predictor for development of hepatocellular carcinoma: Comparison of loss of heterozygosity and replication error
Authors: Kawai Hirokazu , Suda Takeshi , Aoyagi Yutaka , Isokawa Osamu , Mita Yusaku , Waguri Nobuo , Kuroiwa Takashi , Igarashi Masato , Tsukada Kazuhiro , Mori Shigeki , Shimizu Takeaki , Suzuki Yasufumi , Abe Yoichi , Takahashi Toru , Nomoto Minoru , Asakura Hitoshi
Published: March 2004

Both loss of heterozygosity (LOH) and replication error (RER) are considered to be phenotypes of genomic instability. To unveil the role of the genomic instability in hepatocarcinogenesis, frequencies of LOH and RER were simultaneously determined in 15 hepatocellular carcinomas (HCCs), surrounding nontumorous liver tissues (SL), and 13 liver tissues with chronic viral hepatitis void of cancer (NC) by referencing peripheral blood leukocytes (PBLs) from the corresponding donor using 18 microsatellite markers spread throughout the genome. LOH was significantly frequent in HCC compared with that in SL or NC (P = .005, P = .0003, respectively) and observed preferentially at particular microsatellite loci, D1S204, D2S123, D8S1106, D9S266, D16S748, and D19S601. Although the higher prevalence of RER was also significant in HCC compared with that in NC (P = .03), in most cases the errors were detected at very low frequencies and random loci. Both LOH and RER tended to appear more prevalently in SL than in NC. The occurrence rate of LOH was higher in the tissues associated with hepatitis B virus (HBV) than with hepatitis C virus (HCV) infection especially in HCC (P = .03). When referencing SL instead of PBLs, the prevalence of LOH and RER in HCC significantly decreased (P = .02 and P = .03, respectively). These results suggest that LOH is closely associated with multistep hepatocarcinogenesis especially under HBV infection, but RER is imperceptibly associated. The quantitative evaluation of the frequency of LOH by referencing PBLs may be a useful predictor for HCC development in chronic liver diseases.