bluuebunny/crossref_metadata_2025 huggingface dataset:
Activation of mouse liver natural killer cells and NK1.1+T cells by bacterial superantigen-primed Kupffer cells
Authors: Dobashi Hiroshi , Seki Shuhji , Habu Yoshiko , Ohkawa Takashi , Takeshita Seiichiro , Hiraide Hoshio , Sekine Isao
Published: July 2004

Although bacterial superantigens have been well characterized as potent stimulators of T cells, their role in natural killer (NK)-type cells remains largely unknown. In the present study, we examined the effect of bacterial superantigens on mouse liver NK cells and NK1.1 Ag+ (NK1+) T cells. C57BL/6 mice were intravenously injected with staphylococcal enterotoxin B (SEB) or streptococcal pyrogenic exotoxin A (SPE-A), and mononuclear cells (MNC) of various organs were obtained from mice 4 hours after being injected with superantigen. MNC were cultured for 48 hours, and interferon gamma (IFN-γ) levels of supernatants were measured. The antitumor cytotoxicities of the liver and spleen MNC were also evaluated 24 hours after the mice were injected with superantigen. Liver MNC produced more IFN-γ than did splenocytes, and peripheral blood and lung MNC did not produce any detectable IFN-γ. In addition, liver MNC acquired a potent antitumor cytotoxicity by the SEB injection, and both NK cells and NK1+T cells but not cluster of differentiation (CD)8+ T cells were responsible for the cytotoxicity as demonstrated by either in vivo or in vitro cell depletion experiments, and the NK-type cells were partly responsible for the increased serum IFN-γ. Activation of liver NK-type cells was also supported by the fact that liver NK cells proportionally increased and NK1+ T cells augmented their CD11a expressions after SEB injection. The pretreatment of mice with anti-IFN-γ Ab and/or with anti-interleukin-12 (IL-12) Ab diminished the SEB-induced cytotoxicity of liver MNC. Furthermore, the in vivo depletion of Kupffer cells decreased the SEB-induced cytotoxicity of liver MNC. Consistent with these results, liver MNC stimulated with superantigens in the presence of Kupffer cells in vitro produced a greater amount of IFN-γ than did the liver MNC without Kupffer cells or splenocytes. Our results suggest that bacterial superantigen-primed Kupffer cells produce IL-12 and other monokines, while also nonspecifically activating both NK cells and NK1+ T cells to produce IFN-γ.
Hepatic retransplantation in cholestatic liver disease: Impact of the interval to retransplantation on survival and resource utilization
Authors: Kim Ray W. , Wiesner Russell H. , Poterucha John J. , Therneau Terry M. , Malinchoc Michael , Benson Joanne T. , Crippin Jeffrey S. , Klintmalm Goran B. , Rakela Jorge , Starzl Thomas E. , Krom Ruud A. , Evans Roger W. , Dickson Rolland E.
Published: July 2004

The aim of our study was to quantitatively assess the impact of hepatic retransplantation on patient and graft survival and resource utilization. We studied patients undergoing hepatic retransplantation among 447 transplant recipients with primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC) at 3 transplantation centers. Cox proportional hazards regression analysis was used for survival analysis. Measures of resource utilization included the duration of hospitalization, length of stay in the intensive care unit, and the duration of transplantation surgery. Forty-six (10.3%) patients received 2 or more grafts during the follow-up period (median, 2.8 years). Patients who underwent retransplantation had a 3.8-fold increase in the risk of death compared with those without retransplantation (P < .01). Retransplantation after an interval of greater than 30 days from the primary graft was associated with a 6.7-fold increase in the risk of death (P < .01). The survival following retransplantations performed 30 days or earlier was similar to primary transplantations. Resource utilization was higher in patients who underwent multiple consecutive transplantations, even after adjustment for the number of grafts during the hospitalization. Among cholestatic liver disease patients, poor survival following hepatic retransplantation is attributed to late retransplantations, namely those performed more than 30 days after the initial transplantation. While efforts must be made to improve the outcome following retransplantation, a more critical evaluation may be warranted for late retransplantation candidates.
Reduction of telomeric repeats as a possible predictor for development of hepatocellular carcinoma: Convenient evaluation by slot-blot analysis
Authors: Isokawa Osamu , Suda Takeshi , Aoyagi Yutaka , Kawai Hirokazu , Yokota Takashi , Takahashi Toru , Tsukada Kazuhiro , Shimizu Takeaki , Mori Shigeki , Abe Yoichi , Suzuki Yasafumi , Nomoto Minoru , Mita Yusaku , Yanagi Masahiko , Igarashi Hirotaka , Asakura Hitoshi
Published: July 2004

Hepatocellular carcinoma (HCC) mainly arises from the liver with chronic inflammation. Because telomere reduction reflects replicative history in somatic cells, we analyzed the possibility that liver tissues surrounding HCC consist of the cells carrying substantial reduction of telomere. We studied 20 HCC and surrounding noncancerous liver tissues (SL) obtained by surgical resection, and 10 laparoscopically obtained needle biopsy specimens of the liver with chronic inflammation including no overt HCC (CI). Five liver tissues without chronic liver diseases (ND) were also examined. Extracted genomic DNAs were blotted on a nylon membrane, and probed at first with radio-labeled d(TTAGGG)3 and reprobed with radio-labeled d(CCT)7. The intensity caused by d(TTAGGG)3 was divided by that of d(CCT)7. The ratio was defined as telomeric repeats content (TC). Dilution experiments reproducibly revealed almost the same TC. The reduction rate of telomere length through aging estimated by regression analysis of TC was 0.62% per year. Concomitant analyses of TC and average telomere length revealed that both values were significantly correlated (r = .45; P = .009). To compare TC in the liver with respect to chronic inflammation, the value was divided by TC in peripheral blood leukocytes (PBL) from the same donor. The ratio was defined as relative TC (RTC). There was a statistically significant decrease of RTC in CI compared with that in ND (P = .03). Furthermore, RTC in SL was significantly lower than that in CI (P = .0001). These observations suggest that RTC value in liver tissues may digitally indicate a replicative history of hepatocytes under chronic inflammation, and a risk of HCC development.
Impaired mesenteric leukocyte recruitment in experimental portal hypertension in the rat
Authors: Panés Julián , Pérez-del-Pulgar Sofía , Casadevall Maria , Salas Azucena , Pizcueta Pilar , Bosch Jaume , Anderson Donald C. , Granger Neil D. , Piqué Josep M.
Published: July 2004

Increased incidence of septic complications in human and experimental portal hypertension has been documented. Because development of an inflammatory response is essential in defense against infectious agents, the aim of this study was to assess leukocyte-endothelial cell interactions in an experimental model of portal hypertension. Intravital microscopy studies showed that under baseline conditions, leukocyte rolling, adhesion, and emigration in mesenteric venules were similar in control, sham operated (SO), and partial portal vein ligated (PPVL) rats. Compared with either control or SO rats, PPVL animals exhibited a markedly reduced recruitment of rolling, adherent, and emigrated leukocytes in response to leukotriene B4 (LTB4) stimulation. Similarly, platelet-activating factor (PAF) superfusion, which induced a large increment in leukocyte rolling and adherence in control and SO rats, was without any effect in PPVL animals. Endothelial P-selectin expression in control rats, as measured by the double radio-labeled monoclonal antibody (mAb) technique, was not modified by LTB4, but significantly increased in response to PAF. PPVL rats had a significantly lower expression of P-selectin after stimulation with PAF. Neutrophils isolated from PPVL rats exhibited increased L-selectin shedding and CD11b up-regulation in response to PAF and LTB4, compared with neutrophils isolated from SO rats. These observations indicate that portal hypertension is associated with a defective inflammatory response, which is manifested as a decreased recruitment of rolling leukocytes, and subsequently reduced adhesion/emigration. This defect appears to result from a reduced endothelial P-selectin up-regulation and increased L-selectin shedding.
Ischemia impairs liver regeneration after major tissue loss in rodents: Protective effects of interleukin-6
Authors: Selzner Markus , Camargo Carlos A. , Clavien Pierre-Alain
Published: July 2004

The effects of ischemia on the regenerative capacity of the liver after major tissue loss remain unclear. Interleukin-6 (IL-6) has been shown to confer protection in models of normothermic ischemia and reperfusion injury and to initiate hepatocyte proliferation after major hepatectomy. Therefore, we investigated the effects of ischemia on the regenerative capacity of the liver and evaluated the role of IL-6 in reducing reperfusion injury and enhancing hepatic proliferation in models combining ischemia and major hepatectomy. Rats subjected to 70% hepatectomy and 30 minutes of hepatic ischemia showed significantly reduced regenerative capacity (mitotic index, proliferating cell nuclear antigen, and regenerated liver weight) when compared with animals subjected to hepatectomy alone. Pretreatment of animals subjected to hepatectomy and ischemia with recombinant interleukin-6 (rIL-6) completely restored each parameter of regeneration to levels comparable with those of animals subjected to hepatectomy only. Similar results were obtained in IL-6 deficient (IL-6−/−) mice. IL-6−/− mice exposed to ischemia and hepatectomy showed impaired hepatic regeneration when compared with wild-type mice subjected to the same experimental conditions. The use of rIL-6 completely corrected each parameter of regeneration showing the specificity of IL-6 in this type of injury. The impact of IL-6 on animal survival was studied in a model combining 45 minutes of ischemia and 68% hepatectomy. Five of 7 (71%) animals pretreated with rIL-6 survived permanently, whereas all control animals died within 3 days of surgery (P = .02, Fisher's exact test). In conclusion, the study shows that ischemia dramatically impairs the regenerative capacity of the liver. IL-6 appears to be a key protective molecule in reducing injury and promoting regeneration following combined ischemia and major tissue loss.
Lamivudine for chronic delta hepatitis
Authors: Lau Daryl T. , Doo Edward , Park Yoon , Kleiner David E. , Schmid Peter , Kuhns Mary C. , Hoofnagle Jay H.
Published: July 2004

Chronic delta hepatitis is a severe form of chronic liver disease caused by hepatitis delta virus (HDV) infection superimposed on chronic hepatitis B or the hepatitis B surface antigen (HBsAg) carrier state. Therapy of delta hepatitis is currently unsatisfactory. We have evaluated lamivudine (3-thiacytidine), an oral nucleoside analogue with marked effects against hepatitis B, as therapy in 5 patients with chronic hepatitis D. Five men, ages 38 to 65 years, were treated. All had HBsAg, antibody to HDV, and HDV RNA in serum, as well as persistent elevations in alanine aminotransferase (ALT) levels and liver histology showing severe chronic hepatitis with fibrosis or cirrhosis. Lamivudine was given in a dose of 100 mg orally daily for 12 months. Patients were monitored carefully and tested for HBsAg, HBV-DNA and HDV-RNA levels serially during the year of treatment and for 6 months thereafter. Liver biopsies were performed before therapy and repeated after 1 year. Serum levels of HBV DNA fell rapidly in all 5 patients, becoming undetectable even by polymerase chain reaction (PCR) in 4. However, all 5 patients remained HBsAg- and HDV-RNA-positive, and serum ALT levels and liver histology did not improve. All patients tolerated therapy well. When lamivudine was stopped, HBV-DNA levels returned to pretreatment values without a change in disease activity. Lamivudine is a potent inhibitor of HBV-DNA replication, but does not improve disease activity or lower HDV-RNA levels in patients with chronic delta hepatitis.
Acute exacerbation and hepatitis B virus clearance after emergence of YMDD motif mutation during lamivudine therapy
Authors: Liaw Yun-Fan , Chien Rong-Nan , Yeh Chau-Ting , Tsai Sun-Lung , Chu Chia-Ming
Published: July 2004

Lamivudine is a potent inhibitor of hepatitis B virus (HBV) replication, but its long-term use may be associated with HBV tyrosine-methionine-aspartate-aspartate (YMDD) motif mutation. To examine the clinical features and course after emergence of YMDD mutants, 55 patients who received lamivudine therapy over 104 weeks at our unit were assayed for YMDD mutation(s). Thirty-two of them were found to have the YMDD mutation. They continued lamivudine therapy and were followed up weekly or biweekly if clinically indicated. Thirty (93.7%) of them showed elevation of alanine transaminase (ALT), and 13 (40.6%) experienced acute exacerbation at 4 to 94 weeks (median, 24 weeks) after emergence of the YMDD mutant. The incidence of exacerbation is much higher than 4.3% in patients without the YMDD mutation (P = .003). Compared with patients without exacerbation, patients with exacerbation had a significantly higher serum HBV-DNA level after emergence of the YMDD mutant (P < .005). Before exacerbation, serum HBV-DNA level was rising to its peak, followed by the peaking of ALT (247-2,010 U/L) 1 to 4 weeks later. Three patients developed hepatic decompensation, but then in association with hepatitis B e antigen (HBeAg) seroconversion, recovered. Of the 12 evaluable patients, 8 (75%) showed HBeAg seroconversion, and 3 showed mutant clearance within 1 to 5 months after exacerbation. In contrast, none of the patients without exacerbation showed HBeAg seroconversion (P < .001). These results indicate that acute exacerbations may occur after emergence of the YMDD mutation. The incidence, clinicopathological features, and subsequent course, and possibly the underlying immune mechanisms, are similar to those of wild-type HBV chronic infection. Because severe hepatitis may occur, patients should be followed carefully once the YMDD mutant emerges.
Somatostatin alone or combined with emergency sclerotherapy in the treatment of acute esophageal variceal bleeding: A prospective randomized trial
Authors: Villanueva Càndid , Ortiz Jordi , Sàbat Miriam , Gallego Adolfo , Torras Xavier , Soriano German , Sáinz Sergio , Boadas Jaume , Cussó Xavier , Guarner Carlos , Balanzó Joaquim
Published: July 2004

Recent trials have shown that somatostatin (SMT) is as effective as sclerotherapy in the treatment of acute variceal bleeding and that the combination of both treatments is more effective than sclerotherapy alone. To assess whether the addition of sclerotherapy improves the efficacy of SMT alone, all patients admitted to our unit with gastrointestinal bleeding and with suspected cirrhosis received a continuous infusion of SMT (250 μg/h). Endoscopy was performed between 1 and 5 hours later, and patients with esophageal variceal bleeding were randomized to receive or not to receive sclerotherapy. In both groups, SMT infusion was continued for 5 days. Fifty patient admissions were allocated to each group. Therapeutic failure occurred in 21 cases of the SMT group and in 7 cases of the combined-therapy group (P = .002). Failure to control the acute episode occurred in 24% vs. 8% (P = .03) and early rebleeding in 24% vs. 7% (P = .03), respectively. Transfusional requirements were significantly higher in the SMT group, while the incidence of complications was lower (8% vs. 24%; P = .029). In the multivariate analysis, the presence of shock at admission and active bleeding during endoscopy were the variables that better predicted the failure of therapy with SMT alone. Mortality at 6 weeks was similar. These data demonstrate that the addition of sclerotherapy significantly improves the efficacy of SMT alone for the treatment of acute variceal bleeding, although it also increases the rate of complications. Patients with shock and those with active bleeding are more likely to benefit from this combined therapy.
Nonsteroidal anti-inflammatory drug metabolism potentiates interferon alfa signaling by increasing STAT1 phosphorylation
Authors: Giambartolomei Stefania , Artini Marco , Almerighi Cristiana , Moavero Sabrina Maria , Levrero Massimo , Balsano Clara
Published: July 2004

A sustained response to standard interferon therapy for chronic hepatitis C has been demonstrated in no more than 25% of patients. To improve interferon alfa (IFN-α) antiviral effect, a number of combination therapies with IFNs plus other drugs have been proposed for both relapser and nonresponder hepatitis C virus (HCV)-infected patients. Although the causes of IFN resistance in subsets of HCV-infected patients are unknown, both viral and host factors have been involved, including defects in IFN signal transduction and IFN-α/β receptor down-regulation. Here, we report that nonsteroidal anti-inflammatory drugs (NSAIDs), which have been proposed for IFN-α combination therapy in nonresponders, potentiate IFN-α signaling. We found that, in the hepatoma cell lines, CCL13/Chang and HepG2, indomethacin, a selective cyclo-oxygenase 1 and 2 (COX-1 and COX-2) inhibitor, increases IFN-α stimulation of interferon-stimulated response element (ISRE)-dependent transcription in a dose-dependent manner. Interestingly, maximal potentiation was observed with suboptimal IFN-α concentrations. Indomethacin exerts its effects by synergizing with IFN-α in inducing STAT1 activation by phosphorylation, without affecting concurrent Jak1 phosphorylation. Our data indicate that blockade of arachidonic acid (AA) metabolism by indomethacin activates a signaling pathway that converges on STAT1 activation to potentiate IFN-α-dependent gene activation.
Increase by Anaphylatoxin C5a of glucose output in perfused rat liver via prostanoids derived from nonparenchymal cells: Direct action of prostaglandins and indirect action of thromboxane A2 on hepatocytes
Authors: Schieferdecker Henrike L. , Pestel Sabine , Püschel Gerhard P. , Götze Otto , Jungermann Kurt
Published: July 2004

In the perfused rat liver the anaphylatoxin C5a enhanced glucose output, reduced flow, and elevated prostanoid overflow. Because hepatocytes (HCs) do not express C5a receptors, the metabolic C5a actions must be indirect, mediated by e.g. prostanoids from Kupffer cells (KCs) and hepatic stellate cells (HSCs), which possess C5a receptors. Surprisingly, the metabolic C5a effects were not only impaired by the prostanoid synthesis inhibitor, indomethacin, but also by the thromboxane A2 (TXA2) receptor antagonist, daltroban, even though HCs do not express TXA2 receptors. TXA2 did not induce prostaglandin (PG) or an unknown factor release from KCs or sinusoidal endothelial cells (SECs), which express TXA2 receptors, because (1) daltroban did neither influence the C5a-induced release of prostanoids from cultured KCs nor the C5a-dependent activation of glycogen phosphorylase in KC/HC cocultures and because (2) the TXA2 analog, U46619, failed to stimulate prostanoid release from cultured KCs or SECs or to activate glycogen phosphorylase in KC/HC or SEC/HC cocultures. In the perfused liver, Ca2+-deprivation inhibited not only flow reduction but also glucose output elicited by C5a to similar extents as daltroban. Similarly, in the absence of extracellular Ca2+, flow reduction and glucose output induced by U46619 were almost completely prevented, whereas glucose output induced by the directly acting PGF2α was only slightly lowered. Thus, in the perfused rat liver PGs released after C5a-stimulation from KCs and HSCs directly activated glycogen phosphorylase in HCs, and TXA2 enhanced glucose output indirectly mainly by causing hypoxia as a result of flow reduction.
Antibody responses to hepatitis C virus hypervariable region 1: Evidence for cross-reactivity and immune-mediated sequence variation
Authors: Mondelli Mario U. , Cerino Antonella , Lisa Antonella , Brambilla Sabrina , Segagni Laura , Cividini Agostino , Bissolati Morena , Missale Gabriele , Bellati Giorgio , Meola Annalisa , Bruniercole Bruno , Nicosia Alfredo , Galfrè Giovanni , Silini Enrico
Published: July 2004

Sequence heterogeneity of hepatitis C virus (HCV) is unevenly distributed along the genome, and maximal variation is confined to a short sequence of the HCV second envelope glycoprotein (E2), designated hypervariable region 1 (HVR1), whose biological function is still undefined. We prospectively studied serological responses to synthetic oligopeptides derived from HVR1 sequences of patients with acute and chronic HCV infection obtained at baseline and after a defined follow-up period. Extensive serological cross-reactivity for unrelated HVR1 peptides was observed in the majority of the patients. Antibody response was restricted to the IgG1 isotype and was focused on the carboxyterminal end of the HVR1 region. Cross-reactive antibodies could be readily elicited following immunization of mice with multiple antigenic peptides carrying HVR1 sequences derived from our patients. The vigor and heterogeneity of cross-reactive antibody responses were significantly higher in patients with chronic hepatitis compared with those with acute hepatitis and in patients infected with HCV type 2 compared with patients infected with other viral genotypes (predominantly type 1), which suggest that higher time-related HVR1 sequence diversification previously described for type 2 may result from immune selection. The finding of a statistically significant correlation between HVR1 sequence variation, and intensity, and cross-reactivity of humoral immune responses provided stronger evidence in support of the contention that HCV variant selection is driven by the host's immune pressure.
MMP2 activation by collagen I and concanavalin A in cultured human hepatic stellate cells
Authors: Théret Nathalie , Lehti Kaisa , Musso Orlando , Clément Bruno
Published: July 2004

Fibrosis occurs in most chronic liver injuries and results from changes in the balance between synthesis and degradation of extracellular matrix components. In fibrotic livers, there is a markedly increased activity of matrix metalloproteinase 2 (MMP2), a major enzyme involved in extracellular matrix remodeling. We have previously shown that hepatic stellate cells secrete latent MMP2 and that MMP2 activation occurs in coculture of hepatic stellate cells and hepatocytes concomitantly with matrix deposition. In the present work we investigated the effects of various extracellular matrix components and concanavalin A, an inducer of immune-mediated liver injuries, on MMP2 activation in cultured human hepatic stellate cells. Collagen I induced a dose-dependent MMP2 activation, which was not blocked by both actinomycin and cycloheximide. Collagen VI, laminin, and a reconstituted basement membrane (matrigel) were ineffective in inducing activation. Specific antibodies against the subunits of α2β1 integrins, the major collagen I receptor, induced partial inhibition of MMP2 activation. Treatment of cells with concanavalin A resulted in a marked activation of MMP2 that correlated with the proteolytic processing of MT1-MMP, the MMP2 activator, from a Mr=60 kd toward a Mr=43 kd polypeptide. Actinomycin and cycloheximide inhibited the MMP2 activation induced by concanavalin A. Recombinant tissue inhibitor of metalloproteinase-2 and the MMP inhibitor BB-3103, but not PMSF, blocked MMP2 activation induced by collagen I or concanavalin A, and MT1-MMP processing to its Mr-43 kd form. These results suggest that the accumulation of collagen I may specifically contribute to the remodeling of extracellular matrix in fibrotic livers by inducing MMP2 activation.
The alteration of fas receptor and ligand system in hepatocellular carcinomas: How do hepatoma cells escape from the host immune surveillance in vivo?
Authors: Nagao Mitsuo , Nakajima Yoshiyuki , Hisanaga Michiyoshi , Kayagaki Nobuhiko , Kanehiro Hiromichi , Aomatsu Yukio , Ko Saiho , Yagita Hideo , Yamada Takatsugu , Okumura Ko , Nakano Hiroshige
Published: July 2004

Escape from the immune surveillance may play an important role in tumor outgrowth and metastasis. Alteration of the Fas receptor (Fas)/ligand (FasL) system including soluble forms is regarded as one of the mechanisms preventing the immune system from rejecting the tumor cells. However, less attention has been paid to the role of Fas/FasL interaction in vivo. Therefore, we investigated the expression of Fas and FasL by immunohistochemistry and reverse-transcription polymerase chain reaction (RT-PCR) and measured the serum levels of soluble Fas (sFas) and FasL (sFasL) in 44 patients with hepatocellular carcinoma (HCC). In the noncancerous liver tissues, Fas expression was up-regulated in most cases, and FasL expression was detected in 6 cases. In Fas-positive HCC cases (n = 15), the intrahepatic metastatic foci was less (P = .037), apoptosis of tumor cells was more (P = .004), the disease-free survival rate was higher (P = .004), and p53-positive cases were less (P = .003), compared with Fas-negative cases. The sFas and sFasL levels in HCC patients were significantly higher and lower than those in controls, respectively. RT-PCR and immunohistochemistry revealed generation of sFas in the hepatocytes and tumor-infiltrating mononuclear cells rather than in hepatoma cells. Accordingly, hepatoma cells may eliminate Fas expression on themselves and let the hepatocytes and infiltrating mononuclear cells generate sFas to escape from the immune system and to produce metastasis. FasL might contribute to malignant transformation in some circumstances, because hepatocytes in the pericancerous pseudolobules expressed FasL.
Inhibition of 11β-hydroxysteroid dehydrogenase by bile acids in rats with cirrhosis
Authors: Ackermann Daniel , Vogt Bruno , Escher Geneviève , Dick Bernhard , Reichen Jürg , Frey Brigitte M. , Frey Felix J.
Published: July 2004

Renal sodium retention and potassium loss occur early, in many instances in the preascitic state of cirrhosis, an observation that cannot be fully explained by increased aldosterone concentrations. We therefore hypothesize that 11β-hydroxysteroid dehydrogenase 2 (11β-HSD2), which protects mineralocorticoid receptors (MR) from glucocorticosteroids, is down-regulated in cirrhosis. Cirrhosis was induced by bile duct ligation in rats. The urinary ratio of (tetrahydrocorticosterone + 5α-tetrahydrocorticosterone)/ 11-dehydro-tetrahydrocorticosterone [(THB+5α-THB)/THA] was measured by gas chromatography. Cortical collecting tubules (CCT) were isolated by microdis* and used for measurements of the activity of 11β-HSD2 by assessing the conversion of corticosterone to dehydrocorticosterone. The mRNA content of 11β-HSD2 was determined by reverse-transcription polymerase chain reaction (RT-PCR) in CCTs. The urinary ratio of (THB+5α-THB)/THA increased concomitantly with the urinary excretion of bile acids following bile duct ligation. Chenodeoxycholic acid (CDCA) dose-dependently inhibited 11β-HSD2 in CCT with aKi of 19.9 μmol/L. Four weeks after bile duct ligation, 11β-HSD2 activity was decreased in CCT, an observation preceded by a reduced mRNA content at weeks 2 and 3. In cirrhosis, the MR-protecting effect by 11β-HSD2 is diminished, and therefore, endogenous glucocorticoids can induce MR-mediated sodium retention and potassium loss.
Deficient assembly and function of gap junctions in Trf1, a trafficking mutant of the human liver-derived cell line HuH-7
Authors: Stockert Richard J. , Spray David C. , Gao Yang , Suadicani Sylvia O. , Ripley Catherine R. , Novikoff Phyllis M. , Wolkoff Allan W. , Hertzberg Elliot L.
Published: July 2004

The Trf1 cell line, selected from the human hepatoma cell line HuH-7, manifests altered trafficking of various plasma membrane proteins. In particular, there is a striking loss of State 2 asialoglycoprotein receptors. This cell line is shown here to also manifest defects in function and assembly of gap junctions comprising connexin43 (Cx43). No alteration of Cx43 expression or phosphorylation was apparent. Nevertheless, immunostaining of Cx43 revealed that fewer and smaller gap junctions were present at appositional membrane areas in Trf1 cells as compared with parental HuH-7. This correlated with a significant attenuation in gap junction-mediated communication between Trf1 cells as demonstrated by markedly decreased dye transfer and their reduced ability to propagate mechanically evoked Ca2+ waves. Isoelectric focusing (IEF) of Cx43 in HuH-7 cells indicated that the pIs of this protein were significantly lower than that predicted from its amino acid sequence; no differences in pI were evident in Cx43 from Trf1 cells and the HuH-7 cell line. The effects of the Trf1 mutation on assembly and function of gap junctions indicate that this mutation influences trafficking of Cx43. Connexins differ in several respects from other membrane proteins thus far analyzed in Trf1 mutants: gap junctions localize exclusively to the lateral cell surface; they are not glycoproteins; and they do not play a role in endocytic pathways. The disruption of trafficking of Cx43 by this mutation suggests that the Trf1 phenotype is a defect at a common point along the trafficking pathway of cell-surface proteins, irrespective of their ultimate destination on the cell surface or their glycosylation profile.
Glucose intolerance and insulin resistance in cirrhosis are normalized after liver transplantation
Authors: Merli Manuela , Leonetti Frida , Riggio Oliviero , Valeriano Valentina , Ribaudo Mária Cristina , Sprati Fabio , Tisone Giuseppe , Casciani Carlo Umberto , Capocaccia Livio
Published: July 2004

Cirrhosis is often associated with insulin resistance and glucose intolerance. We evaluated if these alterations are restored by liver transplantation (LT). Glucose tolerance (oral glucose tolerance test [OGTT]), peripheral insulin sensitivity (euglycemic insulin clamp technique), glucose oxidation (indirect calorimetry), nonoxidative glucose disposal, and insulin secretion (hyperglycemic clamp technique) were measured in 6 patients (Group 1) before and 6 months after LT, in 12 patients (Group 2) who underwent LT 6 to 30 months previously, and in 6 healthy individuals (controls). In Group 1, glucose tolerance and insulin sensitivity (3.24 ± 0.37 mg/kg/min) were normalized after LT (8.6 ± 0.77 mg/kg/min; P < .0001; P = not significant vs. controls). The improved insulin-mediated glucose uptake was the result of a normalization of nonoxidative glucose disposal. Fasting insulin and C-peptide decreased from 24.6 ± 3.3 μU/mL and 4.37 ± 0.46 ng/dL, respectively, to 12.7 ± 1.9 μU/mL and 2.46 ± 0.5 ng/dL (controls: 10.0 ± 3 μU/mL and 1.45 ± 0.34 ng/dL). The glucose-induced increase of insulin concentration, which was higher before LT, showed a significant reduction, although the first phase of β-cell secretion remained significantly higher compared with that of controls. All these findings were also confirmed in Group 2. The present data indicate that LT normalizes glucose tolerance and insulin sensitivity in cirrhotic patients through an improvement of both hepatic glucose clearance and the peripheral glucose disposal. The latter effect may be the result of the correction of chronic hyperinsulinemia. An increased first-phase β-cell insulin secretion in response to high glucose levels persists, suggesting that a memory of previous insulin resistance is maintained.
Improvement in pulmonary hemodynamics during intravenous epoprostenol (prostacyclin): A study of 15 patients with moderate to severe portopulmonary hypertension
Authors: Krowka Michael J. , Frantz Robert P. , McGoon Michael D. , Severson Cathy , Plevak David J. , Wiesner Russell H.
Published: July 2004

Pulmonary hypertension associated with increased pulmonary vascular resistance (PVR) and occurring in the setting of portal hypertension is referred to as “portopulmonary hypertension.” Intravenous epoprostenol (prostacyclin) is a potent pulmonary and systemic vasodilator with antithrombotic properties. It can decrease PVR and pulmonary artery pressure in patients with primary (idiopathic) pulmonary hypertension. Using right-heart catheterization, we evaluated the acute pulmonary hemodynamic effects of intravenous epoprostenol in patients with moderate to severe pulmonary hypertension (mean pulmonary artery pressure [MPAP] ≥35 mm Hg) associated with clinical manifestations of portal hypertension. Effects of long-term infusion of epoprostenol were also evaluated. We studied 15 consecutive patients with portopulmonary hypertension; 14 underwent acute administration of epoprostenol, and no significant side effects were noted. Ten patients received continuous epoprostenol (range, 8 days-30 months). Acute changes in PVR (−34% ± 18%), MPAP (−16% ± 10%), and cardiac output (CO) (+21 ± 18%), were statistically significant (P < .01). Long-term use of epoprostenol further lowered PVR (−47% ± 12% from baseline and −31% ± 22% from the acute change; P < .05) in the 6 patients restudied by right-heart catheterization. Death occurred in 6 of 10 (60%) of those receiving long-term epoprostenol. In moderate to severe portopulmonary hypertension, intravenous epoprostenol resulted in a significant improvement (both acute and long-term) in PVR, MPAP, and CO. Potential adverse effects on portal hypertension and implications for orthotopic liver transplantation (OLT), however, require further study.
Prevalence of the C282Y mutation of the hemochromatosis gene in liver transplant recipients and donors
Authors: Alanen Kenneth W. , Chakrabarti Subrata , Rawlins Jenna J. , Howson William , Jeffrey Gary , Adams Paul C.
Published: July 2004

Hemochromatosis heterozygotes may be predisposed to end-stage liver disease from other causes. The aims of this study were to determine the prevalence of the hemochromatosis mutation, C282Y, in end-stage liver disease and to determine if transplantation of C282Y heterozygous livers adversely affected survival. The C282Y status of patients who underwent hepatic transplantation and, whenever possible, their donors, was determined and correlated with hepatic iron status. Survival was compared in patients who received livers from heterozygotes and normals. Prevalence of C282Y in recipients was compared with 5,211 voluntary blood donors. Twenty-six C282Y heterozygotes were detected among 304 transplant recipients (8.6%) compared with a prevalence of 8.4% in blood donors. Six of 26 heterozygous recipients (23%) had ≥2+ iron staining in their explanted livers compared with 40 of 277 wild-type livers (14%) (P= ns). There was no significant difference in mean hepatic iron concentration between C282Y heterozygotes and wild-type explanted livers with ≥2+ iron staining. Seven of 31 patients (23%) with alcoholic liver disease were C282Y heterozygotes. Twenty-four heterozygotes were detected in 141 donors (17.0%). Survival did not differ between recipients who received heterozygous or normal livers. The prevalence of C282Y heterozygotes in patients requiring liver transplantation does not differ significantly from the general population. Heterozygotes are not at increased risk of developing end-stage liver disease. Transplantation of C282Y heterozygous livers is a safe, effective practice.
Licensed recombinant hepatitis B vaccines protect chimpanzees against infection with the prototype surface gene mutant of hepatitis B virus
Authors: Ogata Norio , Cote Paul J. , Zanetti Alessandro R. , Miller Roger H. , Shapiro Max , Gerin John , Purcell Robert H.
Published: July 2004

The emergence in vaccinated individuals of hepatitis B virus (HBV) mutants with amino acid substitutions within theadeterminant of the surface protein has raised the possibility that such variants represent neutralization escape mutants. We previously demonstrated that one such mutant HBV, strain AS, with an arginine substituted for glycine at surface gene codon 145, was infectious and pathogenic in seronegative chimpanzees. In the present study, the protective efficacy of licensed hepatitis B vaccines was evaluated against challenge with this mutant virus. Four chimpanzees were immunized with 1 of 2 licensed recombinant hepatitis B vaccines. Shortly after the chimpanzees developed antibodies to hepatitis B surface antigen (anti-HBs), they were challenged intravenously with mutant HBV strain AS. Two unvaccinated chimpanzees served as positive controls. The 4 vaccinated chimpanzees did not develop evidence of HBV infection or hepatitis during 2 years following virus challenge. In contrast, the 2 unvaccinated chimpanzees developed HBV infection and hepatitis. Serum anti-HBs in the vaccinated chimpanzees reacted not only with wild-type surface antigen, but also with mutant surface antigen by competition enzyme-linked immunosorbent assay (ELISA). Thus, immunization of chimpanzees with licensed recombinant hepatitis B vaccines stimulates anti-HBs that is broadly reactive and affords protection against infection with a surface gene mutant of HBV, suggesting that properly immunized individuals are not at significant risk of infection with this prototype variant strain of HBV.
Pathogenesis of chronic hepatitis C: Immunological features of hepatic injury and viral persistence
Authors: Cerny Andreas , Chisari Francis V.
Published: July 2004

The immune response to viral antigens is thought to be responsible for viral clearance and disease pathogenesis during hepatitis C virus (HCV) infection. In chronically infected patients, the T-cell response to the HCV is polyclonal and multispecific, although it is not as strong as the response in acutely infected patients who display a more vigorous T-cell response. Importantly, viral clearance in acutely infected patients is associated with a strong CD4+ helper T-cell response. Thus, the dominant cause of viral persistence during HCV infection may be the development of a weak antiviral immune response to the viral antigens, with corresponding inability to eradicate infected cells. Alternatively, if clearance of HCV from the liver results from the antiviral effect of T-cell-derived cytokines, as has been demonstrated recently for the hepatitis B virus, chronic HCV infection could occur if HCV is not sensitive to such cytokines or if insufficient quantities of cytokines are produced. Liver cell damage may extend from virally infected to uninfected cells via soluble cytotoxic mediators and recruitment and activation of inflammatory cells forming the necroinflammatory response. Additional factors that could contribute to viral persistence are viral inhibition of antigen processing or presentation, modulation of the response to cytotoxic mediators, immunological tolerance to HCV antigens, mutational inactivation of cytotoxic T lymphocyte (CTL) epitopes, mutational conversion of CTL epitopes into CTL antagonists, and infection of immunologically privileged tissues. Analysis of the basis for viral persistence is hampered because the necessary cell culture system and animal model to study this question do not yet exist.
Pretherapy alanine transaminase level as a determinant for hepatitis B e antigen seroconversion during lamivudine therapy in patients with chronic hepatitis B
Authors: Chien Rong-Nan , Liaw Yun-Fan , Atkins Mark
Published: July 2004

In the reported Asian lamivudine trial, the rate of hepatitis B e antigen (HBeAg) seroconversion, defined as HBeAg/hepatitis B virus (HBV) DNA seroclearance and development of anti-HBe, during 52 weeks of treatment was only 13% to 16%. To evaluate whether any factors influenced HBeAg seroconversion, data from 345 patients in that trial were reanalyzed to correlate HBeAg seroconversion with variables including treatment, age, gender, body build, histology, baseline HBV-DNA levels, and alanine transaminase (ALT) levels. Exploratory analysis using stepwise modeling revealed that HBeAg seroconversion correlated highly with pretherapy ALT (P< .001) followed by lamivudine therapy (P= .013), but only marginally with baseline HBV-DNA (P= .071) and cirrhosis (P= .066) for lamivudine 100 mg and placebo comparison. Among these four variables, only pretherapy ALT still had a highly significant (P< .001) correlation and lamivudine therapy had a borderline association (P= .066) for lamivudine 25 mg and placebo comparison. Categorical analysis revealed that HBeAg seroconversion occurred earlier and the cumulative rate was significantly higher in patients with pretherapy ALT values over 2 times the upper limit of normal (ULN) as compared with treated patients with lower ALT levels or untreated control patients with the same ALT levels (P< .001, respectively). The highest HBeAg seroconversion rate was observed in 100 mg lamivudine-treated patients with ALT levels greater than 5 times the ULN (64%) compared with patients with ALT 2 to 5 times the ULN (26%,P= .03); and ALT less than 2 times the ULN, (5%,P< .001). These results suggest that pretherapy ALT is the strongest determinant for HBeAg seroconversion during lamivudine therapy, and should be considered in selecting patients for treatment.
Role of hepatitis C virus in lymphoproliferative disorders after liver transplantation
Authors: Hézode Christophe , Duvoux Christophe , Germanidis Georgios , Roudot-Thoraval Françoise , Vincens Anne-Laure , Gaulard Philippe , Cherqui Daniel , Pawlotsky Jean-Michel , Dhumeaux Daniel
Published: July 2004

It has been suggested that hepatitis C virus (HCV) infection could be associated with B-cell clonal expansion. The aim of this study was to analyze the relationship between lymphoproliferative disorders and HCV infection in liver transplant recipients. We studied 157 patients receiving a liver transplant between January 1989 and May 1997 with a follow-up longer than 3 months. The incidence of posttransplant lymphoproliferative disorders (PTLDs) was analyzed with reference to the indication for liver transplantation, the induction and maintenance immunosuppression, the incidence of acute rejection episodes, and Epstein-Barr virus (EBV) infection. Six PTLDs occurred after a median posttransplant follow-up of 7 months (3.8%). Four of the 6 PTLDs occurred among the 38 patients transplanted for HCV-related cirrhosis, and 2 PTLDs occurred in the 119 patients receiving a liver transplant for non-HCV liver diseases (10.5% vs. 1.7%, respectively; P = .03).The 4-year probability of PTLD was significantly higher in patients receiving a liver transplant for HCV-related cirrhosis than non-HCV liver diseases (12.3% vs. 2.2%, respectively;P= .015). Patients receiving a liver transplant for HCV-related cirrhosis were more likely to receive antithymocyte globulins (ATG). However, in patients treated with ATG, the 4-year probability of PTLD was higher among those patients receiving a liver transplant for HCV-related cirrhosis than for non-HCV liver diseases (27.1% vs. 6.4%, respectively;P= .08). EBV gene products were detected in tumor tissues in 3 of 4 patients with HCV-associated PTLD. Our data suggest that, in addition to EBV infection, 2 mutually nonexclusive factors, i.e., the use of ATG and HCV infection, could play a role in the occurrence of PTLD after a liver transplant for HCV-related cirrhosis.
Effects of vasopressin on portal-systemic collaterals in portal hypertensive rats: Role of nitric oxide and prostaglandin
Authors: Chan Che-Chang , Lee Fa-Yauh , Wang Sun-Sang , Chang Full-Young , Lin Han-Chieh , Chu Chi-Jen , Tai Chun-Ching , Lai I-Nien , Lee Shou-Dong
Published: July 2004

This study investigated the effect of vasopressin on portal-systemic collaterals in portal hypertensive rats and the influence of nitric oxide (NO) and prostaglandin on the responsiveness of collateral vessels to vasopressin. The vascular responsiveness to graded concentrations of vasopressin was tested with or without the incubation of nω-nitro-l-arginine (NNA) (100 μmol/L) and/or indomethacin (10 μmol/L) in perfused collateral vascular beds of rats with portal hypertension induced by partial portal vein ligation. In addition, concentration-response curves to vasopressin with incubation of a vasopressin V1 receptor antagonist d(CH2 )5 Tyr(Me) arginine vasopressin and concentration-response curves to a V2 receptor agonist 1-desamino-8-d-arginine vasopressin were performed. Vasopressin significantly increased the perfusion pressure of collaterals, and this effect was suppressed by the addition of the V1 receptor antagonist. Perfusion with the V2 receptor agonist had no effect on the collaterals. Incubation with NNA, indomethacin, or both significantly potentiated the response of collaterals to vasopressin. In addition, the pressor response to vasopressin in the combination group was significantly higher than that in the NNA-alone group. The results show that vasopressin produces a direct vasoconstrictive effect on the portal-systemic collaterals of portal hypertensive rats. This effect is mediated by the vasopressin V1, but not V2, receptors. The attenuation of the response to vasopressin by NO and prostaglandin suggest a function role of both mediators in the regulation of the portal-systemic collateral circulation in portal hypertensive rats.
Modulation of hepatic acute phase gene expression by epidermal growth factor and src protein tyrosine kinases in murine and human hepatic cells
Authors: Wang Yanping , Ripperger Juergen , Fey Georg H. , Samols David , Kordula Tomek , Wetzler Meir , Van Etten Richard A. , Baumann Heinz
Published: July 2004

As part of systemic inflammatory reactions, interleukin 6 (IL-6) induces acute phase protein (APP) genes through the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway. Epidermal growth factor (EGF), which contributes to the regenerative process after liver injury and also activates STATs, does not induce but attenuates IL-6-stimulated expression of several APP genes in primary mouse hepatocytes. The APP-modifying action of EGF receptor (EGFR) was characterized in HepG2 cells. Although EGF less effectively engages STAT proteins in these cells, it reduces expression of fibrinogen and haptoglobin, but stimulates production of α1-antichymotrypsin and induces transcription through the α1-antichymotrypsin and C-reactive protein promoter. The stimulatory EGFR signal is insensitive to inhibition of JAKs and appears to involve Src kinases and STAT proteins as shown by inhibition through overexpression of C-terminal Src kinase (Csk) and transdominant negative STAT3, respectively. A mediator role of Src is supported by the ability of c-Src and v-Src to activate STATs and induce transcription through APP promoters. Src kinases have been observed in association with the IL-6 receptor; however, inhibition of Src kinases by Csk enhances IL-6-induced transcription. The Csk effect is attributed to prevention of Src kinases from phosphorylating gp130 at the docking site for the signal-moderating protein tyrosine phosphatase SHP-2. The inhibitory EGFR signal on APP expression correlates with the activation of Erk1 and Erk2. The study shows a dual signaling function for EGFR and suggests that the ratio of receptor-activated STATs and Erks influence the level of stimulated or inhibited expression of individual APPs.