Distribution by Scientific Domains
Distribution within Medical Sciences


  • clinical hepatology

  • Selected Abstracts

    Putting flesh and polish on autoimmune hepatitis and moving the disease of exclusion to inclusion,

    HEPATOLOGY, Issue 4 2010
    Albert J. Czaja
    Autoimmune hepatitis emerged during an era when concepts of neonatal immune tolerance, clonal selection of lymphocytes, and "forbidden clones" of activated immune cells were forming. The diagnosis had to be deduced from circumstantial evidence and by exclusion of other conditions. The goals of this review are to demonstrate how a clinician nonscientist can contribute to the maturation of autoimmune hepatitis and to illustrate the principles of clinical investigation that can be applied broadly to other projects. Autoimmune hepatitis initially had to be distinguished from other diseases, and improvements in the tests for viral and immune markers were instrumental in this regard. Diversification of the clinical phenotype to accommodate acute severe, asymptomatic, elderly, and variant forms enhanced the pertinence of the disease, and the formation of the International Autoimmune Hepatitis Group standardized the diagnosis, interconnected investigators, and promoted global acceptance of the condition. Subsequent studies refined current corticosteroid-based therapies, identified prognostic markers, assessed genetic predispositions, explored new pharmacological agents, and forecast the emergence of cellular and molecular interventions. Good fortune, stimulating mentors, career dedication, practical goal selection, protocol compliance, compulsive record keeping, personal resilience, and strong collaborations were the bases for progress. Autoimmune hepatitis exemplifies an evolutionary process in the science of autoimmunity and the people committed to its study. Lessons derived from this experience can be far-reaching. (HEPATOLOGY 2010;52:1177-1184) [source]

    Potential role for Interleukin-28B genotype in treatment decision-making in recent hepatitis C virus infection,

    HEPATOLOGY, Issue 4 2010
    Jason Grebely
    Polymorphisms in the IL28B (interleukin-28B) gene region are important in predicting outcome following therapy for chronic hepatitis C virus (HCV) infection. We evaluated the role of IL28B in spontaneous and treatment-induced clearance following recent HCV infection. The Australian Trial in Acute Hepatitis C (ATAHC) was a study of the natural history and treatment of recent HCV, as defined by positive anti-HCV antibody, preceded by either acute clinical HCV infection within the prior 12 months or seroconversion within the prior 24 months. Factors associated with spontaneous and treatment-induced HCV clearance, including variations in IL28B, were assessed. Among 163 participants, 132 were untreated (n = 52) or had persistent infection (infection duration ,26 weeks) at treatment initiation (n = 80). Spontaneous clearance was observed in 23% (30 of 132 participants). In Cox proportional hazards analysis (without IL28B), HCV seroconversion illness with jaundice was the only factor predicting spontaneous clearance (adjusted hazards ratio = 2.86; 95% confidence interval = 1.24, 6.59; P = 0.014). Among participants with IL28B genotyping (n = 102 of 163 overall and 79 of 132 for the spontaneous clearance population), rs8099917 TT homozygosity (versus GT/GG) was the only factor independently predicting time to spontaneous clearance (adjusted hazard ratio = 3.78; 95% confidence interval = 1.04, 13.76; P = 0.044). Participants with seroconversion illness with jaundice were more frequently rs8099917 TT homozygotes than other (GG/GT) genotypes (32% versus 5%, P = 0.047). Among participants adherent to treatment and who had IL28B genotyping (n = 54), sustained virologic response was similar among TT homozygotes (18 of 29 participants, 62%) and those with GG/GT genotype (16 of 25, 64%, P = 0.884). Conclusion: During recent HCV infection, genetic variations in IL28B region were associated with spontaneous but not treatment-induced clearance. Early therapeutic intervention could be recommended for individuals with unfavorable IL28B genotypes. (HEPATOLOGY 2010;) [source]

    Risk factors for infection during treatment with peginterferon alfa and ribavirin for chronic hepatitis C,

    HEPATOLOGY, Issue 4 2010
    Robert Roomer
    Neutropenia during treatment with peginterferon alfa and ribavirin for chronic hepatitis C virus (HCV) infection is a common cause of dose reductions of peginterferon alfa. These reductions are performed to prevent bacterial and fungal infections, which are common during HCV treatment and can be attributed to neutropenia. The aims of this study were to investigate the occurrence of infections and their relation to neutropenia and to identify potential risk factors for infections during HCV treatment. In this single-center cohort study, 2,876 visits of 321 patients treated with peginterferon alfa and ribavirin were evaluated for neutropenia, infections, dose reductions, and potential risk factors for infection during HCV treatment. The baseline mean absolute neutrophil count (ANC) was 3,420 cells/,L, and 16 patients had a baseline ANC of <1,500 cells/,L. During treatment, neutropenia, which was defined as ANC <750 cells/,L, was observed in 95 patients (29.7%) and ANC <375/,L was observed in 16 patients (5%). Ninety-six infections were observed in 70 patients (21.8%). Thirteen infections (13.5%) were defined as severe. Infections were not correlated with neutropenia during treatment. Dose reductions did not lead to a decrease in infection rate. Multivariate logistic regression analysis revealed that age >55 years (odds ratio [OR] 2.06, 95% confidence interval [CI] 1.19-3.56, P = 0.01) and baseline hyperglycemia (OR 2.17, 95% CI 1.15-4.10, P = 0.016) were associated with an increased risk of infection during HCV treatment. Cirrhosis and chronic obstructive pulmonary disease were not risk factors for infection. Conclusion: Bacterial infections during treatment with peginterferon alfa and ribavirin are not associated with neutropenia. Older patients and patients with poorly controlled diabetes mellitus have a greater risk of developing infections during HCV treatment. (HEPATOLOGY 2010) [source]

    A common variant in the patatin-like phospholipase 3 gene (PNPLA3) is associated with fatty liver disease in obese children and adolescents,,

    HEPATOLOGY, Issue 4 2010
    Nicola Santoro
    The genetic factors associated with susceptibility to nonalcoholic fatty liver disease (NAFLD) in pediatric obesity remain largely unknown. Recently, a nonsynonymous single-nucleotide polymorphism (rs738409), in the patatin-like phospholipase 3 gene (PNPLA3) has been associated with hepatic steatosis in adults. In a multiethnic group of 85 obese youths, we genotyped the PNLPA3 single-nucleotide polymorphism, measured hepatic fat content by magnetic resonance imaging and insulin sensitivity by the insulin clamp. Because PNPLA3 might affect adipogenesis/lipogenesis, we explored the putative association with the distribution of adipose cell size and the expression of some adipogenic/lipogenic genes in a subset of subjects who underwent a subcutaneous fat biopsy. Steatosis was present in 41% of Caucasians, 23% of African Americans, and 66% of Hispanics. The frequency of PNPLA3(rs738409) G allele was 0.324 in Caucasians, 0.183 in African Americans, and 0.483 in Hispanics. The prevalence of the G allele was higher in subjects showing hepatic steatosis. Surprisingly, subjects carrying the G allele showed comparable hepatic glucose production rates, peripheral glucose disposal rate, and glycerol turnover as the CC homozygotes. Carriers of the G allele showed smaller adipocytes than those with CC genotype (P = 0.005). Although the expression of PNPLA3, PNPLA2, PPAR,2(peroxisome proliferator-activated receptor gamma 2), SREBP1c(sterol regulatory element binding protein 1c), and ACACA(acetyl coenzyme A carboxylase) was not different between genotypes, carriers of the G allele showed lower leptin (LEP)(P = 0.03) and sirtuin 1 (SIRT1) expression (P = 0.04). Conclusion: A common variant of the PNPLA3 gene confers susceptibility to hepatic steatosis in obese youths without increasing the level of hepatic and peripheral insulin resistance. The rs738409 PNPLA3 G allele is associated with morphological changes in adipocyte cell size. (HEPATOLOGY 2010.) [source]

    The potent bile acid sequestrant colesevelam is not effective in cholestatic pruritus: Results of a double-blind, randomized, placebo-controlled trial,,

    HEPATOLOGY, Issue 4 2010
    Edith M. M. Kuiper
    Colesevelam is an anion-exchange resin with a 7-fold higher bile acid,binding capacity and fewer side effects than cholestyramine, the current first-line treatment option for cholestatic pruritus. The aim of this trial was to compare the effects of colesevelam and a placebo in patients with cholestatic pruritus. In a randomized, double-blind, investigator-initiated, multicenter trial, patients with cholestatic pruritus, both treatment-naive and previously treated, received 1875 mg of colesevelam or an identical placebo twice daily for 3 weeks. The effect on pruritus was assessed with daily visual analogue scales, quality-of-life scores, and evaluations of cutaneous scratch lesions. The predefined primary endpoint was the proportion of patients with at least a 40% reduction in pruritus visual analogue scale scores. Thirty-eight patients were included, and 35 were evaluable: 17 took colesevelam, 18 took the placebo, 22 were female, 8 were treatment-naive, 14 had primary biliary cirrhosis, and 14 had primary sclerosing cholangitis. The mean serum bile acid levels were comparable between the groups before treatment (P = 0.74), but they were significantly different after treatment (P = 0.01) in favor of patients treated with colesevelam. Thirty-six percent of patients in the colesevelam group reached the primary endpoint versus 35% in the placebo group (P = 1.0). There were no significant differences between the groups with respect to pruritus scores, quality-of-life scores, and severity of cutaneous scratch lesions. Mild side effects occurred in one colesevelam-treated patient and four placebo-treated patients. Conclusion: Although colesevelam significantly decreased serum bile acid levels, this trial was unable to demonstrate that it was more effective than a placebo in alleviating the severity of pruritus of cholestasis. (HEPATOLOGY 2010) [source]

    P2Y13 receptor is critical for reverse cholesterol transport,

    HEPATOLOGY, Issue 4 2010
    Aurélie C. Fabre
    A major atheroprotective functionality of high-density lipoproteins (HDLs) is to promote "reverse cholesterol transport" (RCT). In this process, HDLs mediate the efflux and transport of cholesterol from peripheral cells and its subsequent transport to the liver for further metabolism and biliary excretion. We have previously demonstrated in cultured hepatocytes that P2Y13 (purinergic receptor P2Y, G protein,coupled, 13) activation is essential for HDL uptake but the potential of P2Y13 as a target to promote RCT has not been documented. Here, we show that P2Y13 -deficient mice exhibited a decrease in hepatic HDL cholesterol uptake, hepatic cholesterol content, and biliary cholesterol output, although their plasma HDL and other lipid levels were normal. These changes translated into a substantial decrease in the rate of macrophage-to-feces RCT. Therefore, hallmark features of RCT are impaired in P2Y13 -deficient mice. Furthermore, cangrelor, a partial agonist of P2Y13, stimulated hepatic HDL uptake and biliary lipid secretions in normal mice and in mice with a targeted deletion of scavenger receptor class B type I (SR-BI) in liver (hypomSR-BI,knockoutliver) but had no effect in P2Y13 knockout mice, which indicate that P2Y13 -mediated HDL uptake pathway is independent of SR-BI,mediated HDL selective cholesteryl ester uptake. Conclusion: These results establish P2Y13 as an attractive novel target for modulating RCT and support the emerging view that steady-state plasma HDL levels do not necessarily reflect the capacity of HDL to promote RCT. (HEPATOLOGY 2010) [source]

    Novel mechanism of antibodies to hepatitis B virus in blocking viral particle release from cells,

    HEPATOLOGY, Issue 3 2010
    Avidan U. Neumann
    Antibodies are thought to exert antiviral activities by blocking viral entry into cells and/or accelerating viral clearance from circulation. In particular, antibodies to hepatitis B virus (HBV) surface antigen (HBsAg) confer protection, by binding circulating virus. Here, we used mathematical modeling to gain information about viral dynamics during and after single or multiple infusions of a combination of two human monoclonal anti-HBs (HepeX-B) antibodies in patients with chronic hepatitis B. The antibody HBV-17 recognizes a conformational epitope, whereas antibody HBV-19 recognizes a linear epitope on the HBsAg. The kinetic profiles of the decline of serum HBV DNA and HBsAg revealed partial blocking of virion release from infected cells as a new antiviral mechanism, in addition to acceleration of HBV clearance from the circulation. We then replicated this approach in vitro, using cells secreting HBsAg, and compared the prediction of the mathematical modeling obtained from the in vivo kinetics. In vitro, HepeX-B treatment of HBsAg-producing cells showed cellular uptake of antibodies, resulting in intracellular accumulation of viral particles. Blocking of HBsAg secretion also continued after HepeX-B was removed from the cell culture supernatants. Conclusion: These results identify a novel antiviral mechanism of antibodies to HBsAg (anti-HBs) involving prolonged blocking of the HBV and HBsAg subviral particles release from infected cells. This may have implications in designing new therapies for patients with chronic HBV infection and may also be relevant in other viral infections. (HEPATOLOGY 2010;) [source]

    Long-term entecavir therapy results in the reversal of fibrosis/cirrhosis and continued histological improvement in patients with chronic hepatitis B,,

    HEPATOLOGY, Issue 3 2010
    Ting-Tsung Chang
    One year of treatment with entecavir (0.5 mg daily) in nucleoside-naive patients with hepatitis B e antigen (HBeAg)-positive or HBeAg-negative chronic hepatitis B (CHB) resulted in significantly improved liver histology and virological and biochemical endpoints in comparison with lamivudine. Patients who received at least 3 years of cumulative entecavir therapy in phase 3 studies and a long-term rollover study and underwent long-term liver biopsy were evaluated for improvements in histological appearance. Sixty-nine patients [50 HBeAg-positive and 19 HBeAg-negative] receiving entecavir therapy underwent long-term liver biopsy (median time of biopsy = 6 years, range = 3-7 years). Histological improvement was analyzed for 57 patients who had adequate baseline biopsy samples, baseline Knodell necroinflammatory scores ,2, and adequate long-term biopsy samples. At the time of long-term biopsy, all patients in the cohort had a hepatitis B virus DNA level <300 copies/mL, and 86% had a normalized alanine aminotransferase level. Histological improvement (,2-point decrease in the Knodell necroinflammatory score and no worsening of the Knodell fibrosis score) was observed in 96% of patients, and a ,1-point improvement in the Ishak fibrosis score was found in 88% of patients, including all 10 patients with advanced fibrosis or cirrhosis at the phase 3 baseline. Conclusion: The majority of nucleoside-naive patients with CHB who were treated with entecavir in this long-term cohort achieved substantial histological improvement and regression of fibrosis or cirrhosis. (HEPATOLOGY 2010) [source]

    Epithelial-to-mesenchymal transition of murine liver tumor cells promotes invasion,,

    HEPATOLOGY, Issue 3 2010
    Wei Ding
    Epithelial-to-mesenchymal transition (EMT) is predicted to play a critical role in metastatic disease in hepatocellular carcinoma. In this study, we used a novel murine model of EMT to elucidate a mechanism of tumor progression and metastasis. A total of 2 × 106 liver cells isolated from Ptenloxp/loxp/Alb-Cre+ mice, expanded from a single CD133+CD45, cell clone, passage 0 (P0), were sequentially transplanted to obtain two passages of tumor cells, P1 and P2. Cells were analyzed for gene expression using microarray and real-time polymerase chain reaction. Functional analysis included cell proliferation, migration, and invasion in vitro and orthotopic tumor metastasis assays in vivo. Although P0, P1, and P2 each formed tumors consistent with mixed liver epithelium, within the P2 cells, two distinct cell types were clearly visible: cells with epithelial morphology similar to P0 cells and cells with fibroblastoid morphology. These P2 mesenchymal cells demonstrated increased locomotion on wound healing; increased cell invasion on Matrigel basement membrane; increased EMT-associated gene expression of Snail1, Zeb1, and Zeb2; and down-regulated E-cadherin. P2 mesenchymal cells demonstrated significantly faster tumor growth in vivo compared with P2 epithelial counterparts, with invasion of intestine, pancreas, spleen, and lymph nodes. Furthermore, P2 mesenchymal cells secreted high levels of hepatocyte growth factor (HGF), which we propose acts in a paracrine fashion to drive epithelial cells to undergo EMT. In addition, a second murine liver cancer stem cell line with methionine adenosyltransferase 1a deficiency acquired EMT after sequential transplantations, indicating that EMT was not restricted to Pten-deleted tumors. Conclusion: EMT is associated with a high rate of liver tumor proliferation, invasion, and metastasis in vivo, which is driven by HGF secreted from mesenchymal tumor cells in a feed-forward mechanism. (HEPATOLOGY 2010) [source]

    A multifaceted imbalance of T cells with regulatory function characterizes type 1 autoimmune hepatitis,,

    HEPATOLOGY, Issue 3 2010
    Silvia Ferri
    Immunotolerance is maintained by regulatory T cells (Tregs), including CD4+CD25hi, CD8+CD28,, ,,, and CD3+CD56+ [natural killer T (NKT)] cells. CD4+CD25hi cells are impaired in children with autoimmune hepatitis (AIH). Little is known about Tregs in adults with AIH. The aim of this study was to investigate the frequency and function of Treg subsets in adult patients with AIH during periods of active disease and remission. Forty-seven AIH patients (16 with active disease and 31 in remission) and 28 healthy controls were studied. Flow cytometry was used to evaluate surface markers and function-related intracellular molecules in ,,, CD8+CD28,, NKT, and CD4+CD25hi cells. CD4+CD25hi T cell function was determined by the ability to suppress proliferation and interferon gamma (IFN-,) production by CD4+CD25, target cells. Liver forkhead box P3,positive (FOXP3+) cells were sought by immunohistochemistry. In AIH patients, particularly during active disease, CD4+CD25hi T cells were fewer, expressed lower levels of FOXP3, and were less effective at inhibiting target cell proliferation versus healthy controls. Moreover, although the numbers of CD8+CD28, T cells were similar in AIH patients and healthy controls, NKT cells were numerically reduced, especially during active disease, and produced lower quantities of the immunoregulatory cytokine interleukin-4 versus controls. In contrast, ,, T cells in AIH patients were more numerous versus healthy controls and had an inverted V,1/V,2 ratio and higher IFN-, and granzyme B production; the latter was correlated to biochemical indices of liver damage. There were few FOXP3+ cells within the portal tract inflammatory infiltrate. Conclusion: Our data show that the defect in immunoregulation in adult AIH is complex, and ,, T cells are likely to be effectors of liver damage. (HEPATOLOGY 2010) [source]

    Suppression of liver regeneration and hepatocyte proliferation in hepatocyte-targeted glypican 3 transgenic mice,

    HEPATOLOGY, Issue 3 2010
    Bowen Liu
    Glypican 3 (GPC3) belongs to a family of glycosylphosphatidylinositol-anchored, cell-surface heparan sulfate proteoglycans. GPC3 is overexpressed in hepatocellular carcinoma. Loss-of-function mutations of GPC3 result in Simpson-Golabi-Behmel syndrome, an X-linked disorder characterized by overgrowth of multiple organs, including the liver. Our previous study showed that GPC3 plays a negative regulatory role in hepatocyte proliferation, and this effect may involve CD81, a cell membrane tetraspanin. To further investigate GPC3 in vivo, we engineered transgenic (TG) mice overexpressing GPC3 in the liver under the control of the albumin promoter. GPC3 TG mice with hepatocyte-targeted, overexpressed GPC3 developed normally in comparison with their nontransgenic littermates but had a suppressed rate of hepatocyte proliferation and liver regeneration after partial hepatectomy. Moreover, gene array analysis revealed a series of changes in the gene expression profiles in TG mice (both in normal mice and during liver regeneration). In unoperated GPC3 TG mice, there was overexpression of runt related transcription factor 3 (7.6-fold), CCAAT/enhancer binding protein alpha (2.5-fold), GABA A receptor (2.9-fold), and wingless-related MMTV integration site 7B (2.8-fold). There was down-regulation of insulin-like growth factor binding protein 1 (8.4-fold), Rab2 (5.6-fold), beta-catenin (1.7-fold), transforming growth factor beta type I (3.1-fold), nodal (1.8-fold), and yes-associated protein (1.4-fold). Changes after hepatectomy included decreased expression in several cell cycle,related genes. Conclusion: Our results indicate that in GPC3 TG mice, hepatocyte overexpression of GPC3 suppresses hepatocyte proliferation and liver regeneration and alters gene expression profiles, and potential cell cycle,related proteins and multiple other pathways are involved and affected. (HEPATOLOGY 2010;52:1060,1067) [source]

    Early on-treatment prediction of response to peginterferon alfa-2a for HBeAg-negative chronic hepatitis B using HBsAg and HBV DNA levels,

    HEPATOLOGY, Issue 2 2010
    Vincent Rijckborst
    Peginterferon alfa-2a results in a sustained response (SR) in a minority of patients with hepatitis B e antigen (HBeAg),negative chronic hepatitis B (CHB). This study investigated the role of early on-treatment serum hepatitis B surface antigen (HBsAg) levels in the prediction of SR in HBeAg-negative patients receiving peginterferon alfa-2a. HBsAg (Architect from Abbott) was quantified at the baseline and during treatment (weeks 4, 8, 12, 24, 36, and 48) and follow-up (weeks 60 and 72) in the sera from 107 patients who participated in an international multicenter trial (peginterferon alfa-2a, n = 53, versus peginterferon alfa-2a and ribavirin, n = 54). Overall, 24 patients (22%) achieved SR [serum hepatitis B virus (HBV) DNA level < 10,000 copies/mL and normal alanine aminotransferase levels at week 72]. Baseline characteristics were comparable between sustained responders and nonresponders. From week 8 onward, serum HBsAg levels markedly decreased in sustained responders, whereas only a modest decline was observed in nonresponders. However, HBsAg declines alone were of limited value in the prediction of SR [area under the receiver operating characteristic curve (AUC) at weeks 4, 8, and 12 = 0.59, 0.56, and 0.69, respectively]. Combining the declines in HBsAg and HBV DNA allowed the best prediction of SR (AUC at week 12 = 0.74). None of the 20 patients (20% of the study population) in whom a decrease in serum HBsAg levels was absent and whose HBV DNA levels declined less than 2 log copies/mL exhibited an SR (negative predictive value = 100%). Conclusion: At week 12 of peginterferon alfa-2a treatment for HBeAg-negative CHB, a solid stopping rule was established with a combination of declines in serum HBV DNA and HBsAg levels from the baseline. Quantitative serum HBsAg in combination with HBV DNA enables on-treatment adjustments of peginterferon therapy for HBeAg-negative CHB. (HEPATOLOGY 2010) [source]

    Octamer 4 (Oct4) mediates chemotherapeutic drug resistance in liver cancer cells through a potential Oct4,AKT,ATP-binding cassette G2 pathway,

    HEPATOLOGY, Issue 2 2010
    Xiao Qi Wang
    Chemoresistance presents a major obstacle to the efficacy of chemotherapeutic treatment of cancers. Using chemotherapeutic drugs to select drug-resistant cancer cells in hepatocellular carcinoma (HCC) and several other cancer cell lines, we demonstrate that chemoresistant cells displayed cancer stem cell features, such as increased self-renewal ability, cell motility, multiple drug resistance, and tumorigenicity. Octamer 4 (Oct4) messenger RNA (mRNA) levels were dramatically increased in chemoresistant cancer cells due to DNA demethylation regulation of Oct4. By functional study, Oct4 overexpression enhanced whereas Oct4 knockdown reduced liver cancer cell resistance to chemotherapeutic drugs in vitro and in xenograft tumors. It is known that the Oct4-TCL1-AKT pathway acts on embryonic stem cells and cancer stem cells in cell proliferation through inhibition of apoptosis. We further demonstrate that Oct4 overexpression induced activation of TCL1, AKT, and ABCG2 to mediate chemoresistance, which can be overcome by addition of the PI3K/AKT inhibitor; therefore, a direct pathway of Oct4-TCL1-AKT-ABCG2 or a combination of Oct4-TCL1-AKT with the AKT-ABCG2 pathway could be a potential new mechanism involved in liver cancer cell chemoresistance. Moreover, the clinical significance of the Oct4-AKT-ABCG2 pathway can be demonstrated in HCC patients, with a strong correlation of expression patterns in human HCC tumors. The role of the Oct4-AKT-ABCG2 axis in cancer cell chemoresistant machinery suggests that AKT pathway inhibition (PI3K inhibitors) not only inhibits cancer cell proliferation, but may also enhance chemosensitivity by target potential chemoresistant cells. Conclusion: Oct4, a transcriptional factor of pluripotent cells, can mediate chemoresistance through a potential Oct4-AKT-ABCG2 pathway. (HEPATOLOGY 2010;) [source]

    Cytosolic calcium regulates liver regeneration in the rat,

    HEPATOLOGY, Issue 2 2010
    Laura Lagoudakis
    Liver regeneration is regulated by growth factors, cytokines, and other endocrine and metabolic factors. Calcium is important for cell division, but its role in liver regeneration is not known. The purpose of this study was to understand the effects of cytosolic calcium signals in liver growth after partial hepatectomy (PH). The gene encoding the calcium-binding protein parvalbumin (PV) targeted to the cytosol using a nuclear export sequence (NES), and using a discosoma red fluorescent protein (DsR) marker, was transfected into rat livers by injecting it, in recombinant adenovirus (Ad), into the portal vein. We performed two-thirds PH 4 days after Ad-PV-NES-DsR or Ad-DsR injection, and liver regeneration was analyzed. Calcium signals were analyzed with fura-2-acetoxymethyl ester in hepatocytes isolated from Ad-infected rats and in Ad-infected Hela cells. Also, isolated hepatocytes were infected with Ad-DsR or Ad-PV-NES-DsR and assayed for bromodeoxyuridine incorporation. Ad-PV-NES-DsR injection resulted in PV expression in the hepatocyte cytosol. Agonist-induced cytosolic calcium oscillations were attenuated in both PV-NES,expressing Hela cells and hepatocytes, as compared to DsR-expressing cells. Bromodeoxyuridine incorporation (S phase), phosphorylated histone 3 immunostaining (mitosis), and liver mass restoration after PH were all significantly delayed in PV-NES rats. Reduced cyclin expression and retinoblastoma protein phosphorylation confirmed this observation. PV-NES rats exhibited reduced c-fos induction and delayed extracellular signal-regulated kinase 1/2 phosphorylation after PH. Finally, primary PV-NES,expressing hepatocytes exhibited less proliferation and agonist-induced cyclic adenosine monophosphate responsive element binding and extracellular signal-regulated kinase 1/2 phosphorylation, as compared with control cells. Conclusion: Cytosolic calcium signals promote liver regeneration by enhancing progression of hepatocytes through the cell cycle. (HEPATOLOGY 2010;) [source]

    Carbonyl reductase 1 as a novel target of (,)-epigallocatechin gallate against hepatocellular carcinoma,

    HEPATOLOGY, Issue 2 2010
    Weixue Huang
    Human carbonyl reductase 1 (CBR1) converts the antitumor drug and anthracycline daunorubicin (DNR) into the alcohol metabolite daunorubicinol (DNROL) with significantly reduced antitumor activity and cardiotoxicity, and this limits the clinical use of DNR. Inhibition of CBR1 can thus increase the efficacy and decrease the toxicity of DNR. Here we report that (,)-epigallocatechin gallate (EGCG) from green tea is a promising inhibitor of CBR1. EGCG directly interacts with CBR1 and acts as a noncompetitive inhibitor with respect to the cofactor reduced nicotinamide adenine dinucleotide phosphate and the substrate isatin. The inhibition is dependent on the pH, and the gallate moiety of EGCG is required for activity. Molecular modeling has revealed that EGCG occupies the active site of CBR1. Furthermore, EGCG specifically enhanced the antitumor activity of DNR against hepatocellular carcinoma SMMC7721 cells expressing high levels of CBR1 and corresponding xenografts. We also demonstrated that EGCG could overcome the resistance to DNR by Hep3B cells stably expressing CBR1 but not by RNA interference of CBR1-HepG2 cells. The level of the metabolite DNROL was negatively correlated with that of EGCG in the cell extracts. Finally, EGCG decreased the cardiotoxicity of DNR in a human carcinoma xenograft model with both SMMC7721 and Hep3B cells in mice. Conclusion: These results strongly suggest that EGCG can inhibit CBR1 activity and enhance the effectiveness and decrease the cardiotoxicity of the anticancer drug DNR. These findings also indicate that a combination of EGCG and DNR might represent a novel approach for hepatocellular carcinoma therapy or chemoprevention. (HEPATOLOGY 2010;) [source]

    Loco-regional treatment of hepatocellular carcinoma,

    HEPATOLOGY, Issue 2 2010
    Riccardo Lencioni
    Loco-regional treatments play a key role in the management of hepatocellular carcinoma (HCC). Image-guided tumor ablation is recommended in patients with early-stage HCC when surgical options are precluded. Radiofrequency ablation has shown superior anticancer effects and greater survival benefit with respect to the seminal percutaneous technique, ethanol injection, in meta-analyses of randomized controlled trials, and is currently established as the standard method for local tumor treatment. Novel thermal and nonthermal techniques for tumor ablation,including microwave ablation, irreversible electroporation, and light-activated drug therapy,seem to have potential to overcome the limitations of radiofrequency ablation and warrant further clinical investigation. Transcatheter arterial chemoembolization (TACE) is the standard of care for patients with asymptomatic, noninvasive multinodular tumors at the intermediate stage. The recent introduction of embolic microspheres that have the ability to release the drug in a controlled and sustained fashion has been shown to significantly increase safety and efficacy of TACE with respect to conventional, lipiodol-based regimens. The available data for radioembolization with yttrium-90 suggests that this is a potential new option for patients with HCC, which should be investigated in the setting of randomized controlled trials. Despite the advances and refinements in loco-regional approaches, the long-term survival outcomes of patients managed with interventional techniques are not fully satisfactory, mainly because of the high rates of tumor recurrence. The recent addition of molecular targeted drugs with antiangiogenic and antiproliferative properties to the therapeutic armamentarium for HCC has prompted the design of clinical trials aimed at investigating the synergies between loco-regional and systemic treatments. The outcomes of these trials are eagerly awaited, because they have the potential to revolutionize the treatment of HCC. (HEPATOLOGY 2010;) [source]

    Comparison of surrogate and direct measurement of insulin resistance in chronic hepatitis C virus infection: Impact of obesity and ethnicity,

    HEPATOLOGY, Issue 1 2010
    Khoa D. Lam
    Studies using surrogate estimates show high prevalence of insulin resistance in hepatitis C infection. This study prospectively evaluated the correlation between surrogate and directly measured estimates of insulin resistance and the impact of obesity and ethnicity on this relationship. Eighty-six nondiabetic, noncirrhotic patients with hepatitis C virus (age = 48 ± 7 years, 74% male, 44% white, 22% African American, 26% Latino, 70% genotype 1) were categorized into normal-weight (body mass index [BMI] < 25, n = 30), overweight (BMI = 25-29.9, n = 38), and obese (BMI , 30, n = 18). Insulin-mediated glucose uptake was measured by steady-state plasma glucose (SSPG) concentration during a 240-minute insulin suppression test. Surrogate estimates included: fasting glucose and insulin, glucose/insulin, homeostasis model assessment (HOMA-IR), quantitative insulin sensitivity check index (QUICKI), insulin (I-AUC) and glucose (G-AUC) area under the curve during oral glucose tolerance test, and the Belfiore and Stumvoll indexes. All surrogate estimates correlated with SSPG, but the magnitude of correlation varied (r = 0.30-0.64). The correlation coefficients were highest in the obese. I-AUC had the highest correlation among all ethnic and weight groups (r = 0.57-0.77). HOMA-IR accounted for only 15% of variability in SSPG in the normal weight group. The common HOMA-IR cutoff of ,3 to define insulin resistance had high misclassification rates especially in the overweight group independent of ethnicity. HOMA-IR > 4 had the lowest misclassification rate (75% sensitivity, 88% specificity). Repeat HOMA-IR measurements had higher within-person variation in the obese (standard deviation = 0.77 higher than normal-weight, 95% confidence interval = 0.25-1.30, P = 0.005). Conclusion: Because of limitations of surrogate estimates, caution should be used in interpreting data evaluating insulin resistance especially in nonobese, nondiabetic patients with HCV. HEPATOLOGY 2010 [source]

    Use of surveillance for hepatocellular carcinoma among patients with cirrhosis in the United States,

    HEPATOLOGY, Issue 1 2010
    Jessica A. Davila
    Surveillance for hepatocellular carcinoma (HCC) in patients with cirrhosis is recommended but may not be performed. The extent and determinants of HCC surveillance are unknown. We conducted a population-based United States cohort study of patients over 65 years of age to examine use and determinants of prediagnosis surveillance in patients with HCC who were previously diagnosed with cirrhosis. Patients diagnosed with HCC during 1994-2002 were identified from the linked Surveillance, Epidemiology, and End-Results registry,Medicare databases. We identified alpha-fetoprotein (AFP) and ultrasound tests performed for HCC surveillance, and examined factors associated with surveillance. We identified 1,873 HCC patients with a prior diagnosis of cirrhosis. In the 3 years before HCC, 17% received regular surveillance and 38% received inconsistent surveillance. In a subset of 541 patients in whom cirrhosis was recorded for 3 or more years prior to HCC, only 29% received routine surveillance and 33% received inconsistent surveillance. Among all patients who received regular surveillance, approximately 52% received both AFP and ultrasound, 46% received AFP only, and 2% received ultrasound only. Patients receiving regular surveillance were more likely to have lived in urban areas and had higher incomes than those who did not receive surveillance. Before diagnosis, approximately 48% of patients were seen by a gastroenterologist/hepatologist or by a physician with an academic affiliation; they were approximately 4.5-fold and 2.8-fold, respectively, more likely to receive regular surveillance than those seen by a primary care physician only. Geographic variation in surveillance was observed and explained by patient and physician factors. Conclusion: Less than 20% of patients with cirrhosis who developed HCC received regular surveillance. Gastroenterologists/hepatologists or physicians with an academic affiliation are more likely to perform surveillance. HEPATOLOGY 2010 [source]

    Hepatitis B virus X protein blunts senescence-like growth arrest of human hepatocellular carcinoma by reducing Notch1 cleavage,

    HEPATOLOGY, Issue 1 2010
    Jiejie Xu
    One of the serious sequelae of chronic hepatitis B virus (HBV) infection is hepatocellular carcinoma (HCC). Among all the proteins encoded by the HBV genome, hepatitis B virus X protein (HBx) is highly associated with the development of HCC. Although Notch1 signaling has been found to exert a tumor-suppressive function during HCC development, the mechanism of interaction between HBx expression and Notch1 signaling needs to be explored. In this study, we report that HBx expression in hepatic and hepatoma cells resulted in decreased endogenous protein levels of Notch1 intracellular domain (ICN1) and messenger RNA levels of its downstream target genes. These effects were due to a reduction of Notch1 cleavage by HBx through the suppression of presenilin1 (Psen1) transcription rather than inhibition of Notch1 transcription or its ligands' expression. Through transient HBx expression, decreased ICN1 resulted in enhanced cell proliferation, induced G1-S cell cycle progression, and blunted cellular senescence in vitro. Furthermore, the effect of blunted senescence-like growth arrest by stable HBx expression through suppression of ICN1 was shown in a nude mouse xenograft transplantation model. The correlation of inhibited Psen1-dependent Notch1 signaling and blunted senescence-like growth arrest was also observed in HBV-associated HCC patient tumor samples. Conclusion: Our results reveal a novel function of HBx in blunting senescence-like growth arrest by decreasing Notch1 signaling, which could be a putative molecular mechanism mediating HBV-associated hepatocarcinogenesis. (HEPATOLOGY 2010;) [source]

    Deletion of interleukin-6 in mice with the dominant negative form of transforming growth factor , receptor II improves colitis but exacerbates autoimmune cholangitis,

    HEPATOLOGY, Issue 1 2010
    Weici Zhang
    The role of interleukin-6 (IL-6) in autoimmunity attracts attention because of the clinical usage of monoclonal antibodies to IL-6 receptor (IL-6R), designed to block IL-6 pathways. In autoimmune liver disease, activation of the hepatocyte IL-6/STAT3 (signal transducer and activator of transcription 3) pathway is associated with modulating pathology in acute liver failure, in liver regeneration, and in the murine model of concanavalin A,induced liver inflammation. We have reported that mice expressing a dominant negative form of transforming growth factor , receptor II (dnTGF,RII) under control of the CD4 promoter develop both colitis and autoimmune cholangitis with elevated serum levels of IL-6. Based on this observation, we generated IL-6,deficient mice on a dnTGF-,RII background (dnTGF,RII IL-6,/,) and examined for the presence of antimitochondrial antibodies, levels of cytokines, histopathology, and immunohistochemistry of liver and colon tissues. As expected, based on reports of the use of anti,IL-6R in inflammatory bowel disease, dnTGF,RII IL-6,/, mice manifest a dramatic improvement in their inflammatory bowel disease, including reduced diarrhea and significant reduction in intestinal lymphocytic infiltrates. Importantly, however, autoimmune cholangitis in dnTGF,RII IL-6,/, mice was significantly exacerbated, including elevated inflammatory cytokines, increased numbers of activated T cells, and worsening hepatic pathology. Conclusion: The data from these observations emphasize that there are distinct mechanisms involved in inducing pathology in inflammatory bowel disease compared to autoimmune cholangitis. These data also suggest that patients with inflammatory bowel disease may not be the best candidates for treatment with anti,IL-6R if they have accompanying autoimmune liver disease and emphasize caution for therapeutic use of anti,IL-6R antibody. HEPATOLOGY 2010 [source]

    Carriage of a tumor necrosis factor polymorphism amplifies the cytotoxic T-lymphocyte antigen 4 attributed risk of primary biliary cirrhosis: Evidence for a gene,gene interaction,

    HEPATOLOGY, Issue 1 2010
    Brian D. Juran
    Common genetic variants significantly influence complex diseases such as primary biliary cirrhosis (PBC). We recently reported an association between PBC and a single nucleotide polymorphism (rs231725) of the immunoreceptor gene cytotoxic T-lymphocyte antigen 4 (CTLA4). We hypothesized that PBC risk attributed to this polymorphism might be increased by propensity to an overly robust inflammatory response. Thus, we examined its potential interaction with the commonly studied ,308AG promoter polymorphism (rs1800629) of the tumor necrosis factor (TNF) gene for which the variant TNF2A allele causes increased TNF production. The polymorphisms were genotyped in 866 PBC patients and 761 controls from independent US and Canadian registries; the effects of individual single nucleotide polymorphisms (SNPs) and their interaction on PBC risk was assessed by logistic regression. The reported association of PBC with the CTLA4 "A/A" genotype was replicated in the Canadian cohort and significant for PBC risk in the combined data (odds ratio [OR], 1.68; P = 0.0005). TNF2A allele frequency was elevated in PBC patients, but only reached borderline significance using the combined data (OR, 1.21; P = 0.042). Analysis showed that TNF2A carriage was significantly increased in CTLA4 "A/A" PBC patients compared with CTLA4 "A/A" controls (39.7% versus 16.5%, P = 0.0004); no apparent increase of TNF2A carriage was noted in CTLA4 "A/G" or "G/G" individuals. Finally, interaction under a logistic model was highly significant, as TNF2A carriage in combination with the CTLA4 "A/A" genotype was present in 6.5% of PBC patients, compared with 1.7% of controls (OR, 3.98; P < 0.0001). Conclusion: TNF2A amplifies the CTLA4 rs231725 "A/A" genotype risk for PBC. Although the mechanisms remain unclear, the premise that deficiency in T-cell regulation resulting in an increased risk of PBC is amplified by overexpression of an important proinflammatory cytokine provides a basis for future functional studies. HEPATOLOGY 2010 [source]

    Tumor necrosis factor,like weak inducer of apoptosis is a mitogen for liver progenitor cells,,

    HEPATOLOGY, Issue 1 2010
    Janina E. E. Tirnitz-Parker
    Liver progenitor cells (LPCs) represent the cell compartment facilitating hepatic regeneration during chronic injury while hepatocyte-mediated repair mechanisms are compromised. LPC proliferation is frequently observed in human chronic liver diseases such as hereditary hemochromatosis, fatty liver disease, and chronic hepatitis. In vivo studies have suggested that a tumor necrosis factor family member, tumor necrosis factor,like weak inducer of apoptosis (TWEAK), is promitotic for LPCs; whether it acts directly is not known. In our murine choline-deficient, ethionine-supplemented (CDE) model of chronic liver injury, TWEAK receptor [fibroblast growth factor-inducible 14 (Fn14)] expression in the whole liver is massively upregulated. We therefore set out to investigate whether TWEAK/Fn14 signaling promotes the regenerative response in CDE-induced chronic liver injury by mitotic stimulation of LPCs. Fn14 knockout (KO) mice showed significantly reduced LPC numbers and attenuated inflammation and cytokine production after 2 weeks of CDE feeding. The close association between LPC proliferation and activation of hepatic stellate cells in chronic liver injury prompted us to investigate whether fibrogenesis was also modulated in Fn14 KO animals. Collagen deposition and expression of key fibrogenesis mediators were reduced after 2 weeks of injury, and this correlated with LPC numbers. Furthermore, the injection of 2-week-CDE-treated wildtype animals with TWEAK led to increased proliferation of nonparenchymal pan cytokeratin,positive cells. Stimulation of an Fn14-positive LPC line with TWEAK led to nuclear factor kappa light chain enhancer of activated B cells (NF,B) activation and dose-dependent proliferation, which was diminished after targeting of the p50 NF,B subunit by RNA interference. Conclusion: TWEAK acts directly and stimulates LPC mitosis in an Fn14-dependent and NF,B-dependent fashion, and signaling via this pathway mediates the LPC response to CDE-induced injury and regeneration. (HEPATOLOGY 2010) [source]

    Mitochondrial superoxide dismutase and glutathione peroxidase in idiosyncratic drug-induced liver injury,,

    HEPATOLOGY, Issue 1 2010
    M. Isabel Lucena
    Drug-induced liver injury (DILI) susceptibility has a potential genetic basis. We have evaluated possible associations between the risk of developing DILI and common genetic variants of the manganese superoxide dismutase (SOD2 Val16Ala) and glutathione peroxidase (GPX1 Pro200Leu) genes, which are involved in mitochondrial oxidative stress management. Genomic DNA from 185 DILI patients assessed by the Council for International Organizations of Medical Science scale and 270 sex- and age-matched controls were analyzed. The SOD2 and GPX1 genotyping was performed using polymerase chain reaction restriction fragment length polymorphism and TaqMan probed quantitative polymerase chain reaction, respectively. The statistical power to detect the effect of variant alleles with the observed odds ratio (OR) was 98.2% and 99.7% for bilateral association of SOD2 and GPX1, respectively. The SOD2 Ala/Ala genotype was associated with cholestatic/mixed damage (OR = 2.3; 95% confidence interval [CI] = 1.4-3.8; corrected P [Pc] = 0.0058), whereas the GPX1 Leu/Leu genotype was associated with cholestatic injury (OR = 5.1; 95%CI = 1.6-16.0; Pc = 0.0112). The presence of two or more combined risk alleles (SOD2 Ala and GPX1 Leu) was more frequent in DILI patients (OR = 2.1; 95%CI = 1.4-3.0; Pc = 0.0006). Patients with cholestatic/mixed injury induced by mitochondria hazardous drugs were more prone to have the SOD2 Ala/Ala genotype (OR = 3.6; 95%CI = 1.4-9.3; Pc = 0.02). This genotype was also more frequent in cholestatic/mixed DILI induced by pharmaceuticals producing quinone-like or epoxide metabolites (OR = 3.0; 95%CI = 1.7-5.5; Pc = 0.0008) and S-oxides, diazines, nitroanion radicals, or iminium ions (OR = 16.0; 95%CI = 1.8-146.1; Pc = 0.009). Conclusion: Patients homozygous for the SOD2 Ala allele and the GPX1 Leu allele are at higher risk of developing cholestatic DILI. SOD2 Ala homozygotes may be more prone to suffer DILI from drugs that are mitochondria hazardous or produce reactive intermediates. (HEPATOLOGY 2010) [source]

    Fitness versus fatness: Moving beyond weight loss in nonalcoholic fatty liver disease,,

    HEPATOLOGY, Issue 1 2010
    Nathan A. Johnson
    The rapid emergence of nonalcoholic fatty liver disease (NAFLD) as a cause of both liver-related morbidity and mortality and cardiometabolic risk has led to the search for effective lifestyle strategies to reduce liver fat. Lifestyle intervention comprising dietary restriction in conjunction with increased physical activity has shown clear hepatic benefits when weight loss approximating 3%-10% of body weight is achieved. Yet, the poor sustainability of weight loss challenges the current therapeutic focus on body weight and highlights the need for alternative strategies for NAFLD management. Epidemiologic data show an independent relationship between liver fat, physical activity, and fitness, and a growing body of longitudinal research demonstrates that increased physical activity participation per se significantly reduces hepatic steatosis and serum aminotransferases in individuals with NAFLD, independent of weight loss. Mechanistic insights to explain this interaction are outlined, and recommendations for the implementation of lifestyle intervention involving physical activity are discussed. In light of the often poor sustainability of weight loss strategies, and the viability of physical activity therapy, clinicians should assess physical fitness and physical activity habits, educate patients on the benefits of fitness outside of weight loss, and focus on behavior change which promotes physical activity adoption. (HEPATOLOGY 2010) [source]

    Themes of liver transplantation,

    HEPATOLOGY, Issue 6 2010
    Thomas E. Starzl
    Liver transplantation was the product of five interlocking themes. These began in 1958-1959 with canine studies of then theoretical hepatotrophic molecules in portal venous blood (Theme I) and with the contemporaneous parallel development of liver and multivisceral transplant models (Theme II). Further Theme I investigations showed that insulin was the principal, although not the only, portal hepatotrophic factor. In addition to resolving long-standing controversies about the pathophysiology of portacaval shunt, the hepatotrophic studies blazed new trails in the regulation of liver size, function, and regeneration. They also targeted inborn metabolic errors (e.g., familial hyperlipoproteinemia) whose palliation by portal diversion presaged definitive correction with liver replacement. Clinical use of the Theme II transplant models depended on multiple drug immunosuppression (Theme III, Immunology), guided by an empirical algorithm of pattern recognition and therapeutic response. Successful liver replacement was first accomplished in 1967 with azathioprine, prednisone, and antilymphoid globulin. With this regimen, the world's longest surviving liver recipient is now 40 years postoperative. Incremental improvements in survival outcome occurred (Theme IV) when azathioprine was replaced by cyclosporine (1979), which was replaced in turn by tacrolimus (1989). However, the biologic meaning of alloengraftment remained enigmatic until multilineage donor leukocyte microchimerism was discovered in 1992 in long-surviving organ recipients. Seminal mechanisms were then identified (clonal exhaustion-deletion and immune ignorance) that linked organ engraftment and the acquired tolerance of bone marrow transplantation and eventually clarified the relationship of transplantation immunology to the immunology of infections, neoplasms, and autoimmune disorders. With this insight, better strategies of immunosuppression have evolved. As liver and other kinds of organ transplantation became accepted as healthcare standards, the ethical, legal, equity, and the other humanism issues of Theme V have been resolved less conclusively than the medical-scientific problems of Themes I-IV. HEPATOLOGY 2010 [source]

    Serum hepatitis B surface antigen and hepatitis B e antigen titers: Disease phase influences correlation with viral load and intrahepatic hepatitis B virus markers,,

    HEPATOLOGY, Issue 6 2010
    Alexander J.V. Thompson
    Although threshold levels for hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) titers have recently been proposed to guide therapy for chronic hepatitis B (CHB), their relationship to circulating hepatitis B virus (HBV) DNA and intrahepatic HBV replicative intermediates, and the significance of emerging viral variants, remains unclear. We therefore tested the hypothesis that HBsAg and HBeAg titers may vary independently of viral replication in vivo. In all, 149 treatment-naïve CHB patients were recruited (HBeAg-positive, n = 71; HBeAg-negative, n = 78). Quantification of HBeAg and HBsAg was performed by enzyme immunoassay. Virological characterization included serum HBV DNA load, HBV genotype, basal core promoter (BCP)/precore (PC) sequence, and, in a subset (n = 44), measurement of intrahepatic covalently closed circular DNA (cccDNA) and total HBV DNA, as well as quantitative immunohistochemical (IHC) staining for HBsAg. In HBeAg-positive CHB, HBsAg was positively correlated with serum HBV DNA and intrahepatic cccDNA and total HBV DNA (r = 0.69, 0.71, 0.76, P < 0.01). HBeAg correlated with serum HBV DNA (r = 0.60, P < 0.0001), although emerging BCP/PC variants reduced HBeAg titer independent of viral replication. In HBeAg-negative CHB, HBsAg correlated poorly with serum HBV DNA (r = 0.28, P = 0.01) and did not correlate with intrahepatic cccDNA nor total HBV DNA. Quantitative IHC for hepatocyte HBsAg confirmed a relationship with viral replication only in HBeAg-positive patients. Conclusion: The correlation between quantitative HBsAg titer and serum and intrahepatic markers of HBV replication differs between patients with HBeAg-positive and HBeAg-negative CHB. HBeAg titers may fall independent of viral replication as HBeAg-defective variants emerge prior to HBeAg seroconversion. These findings provide new insights into viral pathogenesis and have practical implications for the use of quantitative serology as a clinical biomarker. (HEPATOLOGY 2010) [source]

    Pharmacology and safety of glycerol phenylbutyrate in healthy adults and adults with cirrhosis,,

    HEPATOLOGY, Issue 6 2010
    Brendan M. McGuire
    Phenylbutyric acid (PBA), which is approved for treatment of urea cycle disorders (UCDs) as sodium phenylbutyrate (NaPBA), mediates waste nitrogen excretion via combination of PBA-derived phenylacetic acid with glutamine to form phenylactylglutamine (PAGN) that is excreted in urine. Glycerol phenylbutyrate (GPB), a liquid triglyceride pro-drug of PBA, containing no sodium and having favorable palatability, is being studied for treatment of hepatic encephalopathy (HE). In vitro and clinical studies have been performed to assess GPB digestion, safety, and pharmacology in healthy adults and individuals with cirrhosis. GPB hydrolysis was measured in vitro by way of pH titration. Twenty-four healthy adults underwent single-dose administration of GPB and NaPBA and eight healthy adults and 24 cirrhotic subjects underwent single-day and multiple-day dosing of GPB, with metabolites measured in blood and urine. Simulations were performed to assess GPB dosing at higher levels. GPB was hydrolyzed by human pancreatic triglyceride lipase, pancreatic lipase-related protein 2, and carboxyl-ester lipase. Clinical safety was satisfactory. Compared with NaPBA, peak metabolite blood levels with GPB occurred later and were lower; urinary PAGN excretion was similar but took longer. Steady state was achieved within 4 days for both NaPBA and GPB; intact GPB was not detected in blood or urine. Cirrhotic subjects converted GPB to PAGN similarly to healthy adults. Simulations suggest that GPB can be administered safely to cirrhotic subjects at levels equivalent to the highest approved NaPBA dose for UCDs. Conclusion: GPB exhibits delayed release characteristics, presumably reflecting gradual PBA release by pancreatic lipases, and is well tolerated in adults with cirrhosis, suggesting that further clinical testing for HE is warranted. (HEPATOLOGY 2010;) [source]

    S -adenosylmethionine regulates dual-specificity mitogen-activated protein kinase phosphatase expression in mouse and human hepatocytes,

    HEPATOLOGY, Issue 6 2010
    Maria Lauda Tomasi
    Increased mitogen-activated protein kinase (MAPK) activity correlates with a more malignant hepatocellular carcinoma (HCC) phenotype. There is a reciprocal regulation between p44/42 MAPK (extracellular signal-regulated kinase [ERK]1/2) and the dual-specificity MAPK phosphatase MKP-1/DUSP1. ERK phosphorylates DUSP1, facilitating its proteasomal degradation, whereas DUSP1 inhibits ERK activity. Methionine adenosyltransferase 1a (Mat1a) knockout (KO) mice express hepatic S -adenosylmethionine (SAM) deficiency and increased ERK activity and develop HCC. The aim of this study was to examine whether DUSP1 expression is regulated by SAM and if so, elucidate the molecular mechanisms. Studies were conducted using Mat1a KO mice livers, cultured mouse and human hepatocytes, and 20S and 26S proteasomes. DUSP1 messenger RNA (mRNA) and protein levels were reduced markedly in livers of Mat1a KO mice and in cultured mouse and human hepatocytes with protein falling to lower levels than mRNA. SAM treatment protected against the fall in DUSP1 mRNA and protein levels in mouse and human hepatocytes. SAM increased DUSP1 transcription, p53 binding to DUSP1 promoter, and stability of its mRNA and protein. Proteasomal chymotrypsin-like and caspase-like activities were increased in Mat1a KO livers and cultured hepatocytes, which was blocked by SAM treatment. SAM inhibited chymotrypsin-like and caspase-like activities by 40% and 70%, respectively, in 20S proteasomes and caused rapid degradation of some of the 26S proteasomal subunits, which was blocked by the proteasome inhibitor MG132. SAM treatment in Mat1a KO mice for 7 days raised SAM, DUSP1, mRNA and protein levels and lowered proteosomal and ERK activities. Conclusion: DUSP1 mRNA and protein levels are lower in Mat1a KO livers and fall rapidly in cultured hepatocytes. SAM treatment increases DUSP1 expression through multiple mechanisms, and this may suppress ERK activity and malignant degeneration. HEPATOLOGY 2010 [source]

    Specific human leukocyte antigen class I and II alleles associated with hepatitis C virus viremia,,§

    HEPATOLOGY, Issue 5 2010
    Mark H. Kuniholm
    Studies of human leukocyte antigen (HLA) alleles and their relation with hepatitis C virus (HCV) viremia have had conflicting results. However, these studies have varied in size and methods, and few large studies assessed HLA class I alleles. Only one study conducted high-resolution class I genotyping. The current investigation therefore involved high-resolution HLA class I and II genotyping of a large multiracial cohort of U.S. women with a high prevalence of HCV and HIV. Our primary analyses evaluated associations between 12 HLA alleles identified through a critical review of the literature and HCV viremia in 758 HCV-seropositive women. Other alleles with >5% prevalence were also assessed; previously unreported associations were corrected for multiple comparisons. DRB1*0101 (prevalence ratio [PR] = 1.7; 95% confidence interval [CI] = 1.1,2.6), B*5701 (PR=2.0; 95% CI = 1.0,3.1), B*5703 (PR = 1.7; 95% CI = 1.0,2.5), and Cw*0102 (PR = 1.9; 95% CI = 1.0,3.0) were associated with the absence of HCV RNA (i.e., HCV clearance), whereas DRB1*0301 (PR = 0.4; 95% CI = 0.2,0.7) was associated with HCV RNA positivity. DQB1*0301 was also associated with the absence of HCV RNA but only among HIV-seronegative women (PR = 3.4; 95% CI = 1.2,11.8). Each of these associations was among those predicted. We additionally studied the relation of HLA alleles with HCV infection (serostatus) in women at high risk of HCV from injection drug use (N = 838), but no significant relationships were observed. Conclusion: HLA genotype influences the host capacity to clear HCV viremia. The specific HLA associations observed in the current study are unlikely to be due to chance because they were a priori hypothesized. (HEPATOLOGY 2010.) [source]

    Glucagon-like peptide-1 receptor is present on human hepatocytes and has a direct role in decreasing hepatic steatosis in vitro by modulating elements of the insulin signaling pathway,

    HEPATOLOGY, Issue 5 2010
    Nitika Arora Gupta
    Glucagon-like peptide 1 (GLP-1) is a naturally occurring peptide secreted by the L cells of the small intestine. GLP-1 functions as an incretin and stimulates glucose-mediated insulin production by pancreatic , cells. In this study, we demonstrate that exendin-4/GLP-1 has a cognate receptor on human hepatocytes and that exendin-4 has a direct effect on the reduction of hepatic steatosis in the absence of insulin. Both glucagon-like peptide 1 receptor (GLP/R) messenger RNA and protein were detected on primary human hepatocytes, and receptor was internalized in the presence of GLP-1. Exendin-4 increased the phosphorylation of 3-phosphoinositide-dependent kinase-1 (PDK-1), AKT, and protein kinase C , (PKC-,) in HepG2 and Huh7 cells. Small interfering RNA against GLP-1R abolished the effects on PDK-1 and PKC-,. Treatment with exendin-4 quantitatively reduced triglyceride stores compared with control-treated cells. Conclusion: This is the first report that the G protein,coupled receptor GLP-1R is present on human hepatocytes. Furthermore, it appears that exendin-4 has the same beneficial effects in vitro as those seen in our previously published in vivo study in ob/ob mice, directly reducing hepatocyte steatosis. Future use for human nonalcoholic fatty liver disease, either in combination with dietary manipulation or other pharmacotherapy, may be a significant advance in treatment of this common form of liver disease. (HEPATOLOGY 2010) [source]