bluuebunny/crossref_metadata_2025 huggingface dataset:
Alteration of Na+ homeostasis as a critical step in the development of irreversible hepatocyte injury after adenosine triphosphate depletion
Authors: Carini Rita , Bellomo Giorgio , Benedetti Angelo , Fulceri Rosella , Gamberucci Alessandra , Parola Maurizio , Dianzani Mario U. , Albano Emanuele
Published: March 2007

The exposure of isolated hepatocytes to the redox-cycling quinone menadione caused an early loss of mitochondrial membrane potential, adenosine triphosphate (ATP) depletion, and decreased intracellular pH. These alterations were followed by an increase in intracellular Na+ and, ultimately, cell death. If HCO3
− was omitted from the incubation buffer, or the hepatocytes were incubated in an acidic medium (pH 6.5) the accumulation of Na+ was markedly reduced. Inhibition of the Na+/H+ exchanger and of the Na+/HCO3
− cotransporter by, respectively, amiloride and 4,4′-di-isothiocyano-2,2′-disulfonic acid stilbene (DIDS) suppressed the initial Na+ influx but did not prevent subsequent Na+ accumulation, because amiloride and DIDS inhibited the Na+/K+ pump. The omission of HCO3
− from the extracellular medium or the incubation in acidic conditions also prevented menadione toxicity, without interfering with the loss of mitochondrial membrane potential and with ATP depletion. A similar protection was evident when hepatocytes were incubated with menadione in a medium without Na+. The preservation of adequate levels of ATP by supplementing hepatocytes with fructose allowed the initial Na+ load to be recovered and provided partial protection against menadione toxicity. These effects were suppressed if Na+/K+-ATPase was inhibited with ouabain. Taken together, these results indicated that the activation of the Na+/HCO3
− cotransporter and of the Na+/H+ exchanger in response to the decrease of intracellular pH stimulated an enhanced influx of Na+. When the activity of the Na+/K+ pump was not able to control Na+ levels because of ATP depletion, such an uncontrolled Na+ influx precipitated irreversible injury and caused hepatocyte death. (Hepatology 1995; 21:1089-1098.)
Walking the ethical highwire: Genetic screening and hereditary tyrosinemia
Authors: Romero René , Lavine Joel E.
Published: March 2007

Background:

Hereditary tyrosinemia type I is an autosomal recessive inborn error of metabolism caused by a deficiency of the enzyme fumarylacetoacetate hydrolase. The disorder clusters in the Saguenay-Lac-St.-Jean area of Quebec. In this region, 1 of 1846 newborns is affected and 1 of every 22 persons is thought to be a carrier. Recently, we identified a splice mutation and two nonsense mutations in the fumarylacetoacetate hydrolase gene in two patients from Quebec with tyrosinemia type I.

Methods:

We used allele-specific-oligonucleotide hybridization to examine the frequency of these three candidate mutations in patients with tyrosinemia type I and in the population of Quebec.

Results:

The splice mutation was found in 100 percent of patients from the Saguenay-Lac-St.-Jean area and in 28 percent of patients from other regions of the world. Of 25 patients from the Saguenay-Lac-St.-Jean region, 20 (80 percent) were homozygous for this mutation, a guanine-to-adenine change in the splice-donor sequence in intron 12 of the gene, indicating that it causes most cases of tyrosinemia type I in the region. The frequency of carrier status, based on screening of blood spots from newborns, was about 1 per 25 in the Saguenay-Lac-St.-Jean population and about 1 per 66 overall in Quebec.

Conclusions:

This study identified the most prevalent mutation causing hereditary tyrosinemia in French Canada; it also showed the feasibility of DNA-based testing for carriers in the population at risk. (N Engl J Med 1994;331:353-7.)
The prevalence and spectrum of colonic lesions in patients with cirrhotic and noncirrhotic portal hypertension
Authors: Ganguly Siddarth , Sarin Shiv K. , Bhatia Vivek , Lahoti Deepak
Published: March 2007

Portal hypertension diffusely affects the gastrointestinal tract. The frequency and profile of distinct colonic mucosal lesions (portal colopathy) and rectal varices (RV; veins >4 cm above the anal verge) is not well studied. Fifty consecutive patients with portal hypertension (25 with cirrhosis, 10 with noncirrhotic portal fibrosis [NCPF], and 15 with extrahepatic portal vein obstruction [EHPVO]) were assessed clinically and by upper and lower gastrointestinal (GI) endoscopy. Colorectal lesions were seen in 35 (70%) patients, significantly more often in bleeders than in nonbleeders. Rectal varices were detected in 22 (44%) patients; larger and more often seen in EHPVO (80%) than in cirrhosis (28%) and NCPF (30%) (P < 0.01) patients. Portal colopathy was seen in 26 (52%) patients, with nearly similar frequency in cirrhotics, NCPF, and EHPVO patients. Previous sclerotherapy or presence of gastric varices had little influence on the development of these lesions. An association (P < 0.01) was, however, seen between the presence of colopathy and portal gastropathy. Overt bleeding was seen in 8% and 4% of patients with RV and colopathy, respectively. In conclusion, our results demonstrate that colorectal lesions are present in about two thirds of patients with portal hypertension. Patients with portal hypertension and lower GI bleeding should be colonoscoped. Patients with extrahepatic portal vein obstruction may in turn benefit from baseline sigmoidoscopic examination to define the presence and size of rectal varices.
Role of thrombosis in the pathogenesis of congestive hepatic fibrosis (cardiac cirrhosis)
Authors: Wanless Ian R. , Liu Julia J. , Butany Jagdish
Published: March 2007

The pathogenesis of congestive cirrhosis is generally thought to be a reaction of the hepatic stroma to hypoxia, pressure, or necrosis. This does not explain the poor correlation between symptoms and severity of fibrosis and the irregular distribution of fibrosis within the liver. We have observed healed hepatic vein (HV) thrombosis in patients with congestive heart failure (CHF). The purposes of this study were to document hepatic vascular lesions in autopsy livers of patients with chronic CHF, to determine the role of these lesions in the pathogenesis of congestive cirrhosis, and to refine the definition of congestive cirrhosis. Twenty-five livers were studied, 13 with multiple large blocks 4 × 5 cm. Sections were graded for parenchymal fibrous septa, sinusoidal fibrosis, and intimal fibrosis of portal veins (PVs) and HVs. Fibrous septa were found in livers of 7 of 13 patients with CHF and in none of 12 controls without CHF (P = 0.007). Parenchymal fibrosis was highly variable in distribution, often with severe septation in some areas and nearly normal morphology in others. Intimal fibrosis and obstruction of small- and medium-HVs were found only in livers of patients with CHF. The vascular lesions were confined to regions with fibrous septation and had morphology suggestive of organized thrombosis. Acute thrombi in sinusoids were noted in livers of 4 patients with CHF and in livers of 2 patients without CHF. These findings support the hypothesis that congestive cirrhosis is a response to intrahepatic thrombosis. The pattern of disease suggests that thrombus begins in sinusoids, occasionally propagates to HVs, and causes secondary local PV thrombosis, ischemia, parenchymal extinction, and fibrosis.
Cardiovascular effects of octreotide in patients with hepatic cirrhosis
Authors: McCormick Aiden P. , Chin Jason , Greenslade Lynda , Karatapanis Stelios , Dick Robert , McIntyre Neil , Burroughs Andrew K.
Published: March 2007

Octreotide is thought to reduce splanchnic and variceal blood flow with minimal effects on the systemic circulation in cirrhotic patients with portal hypertension. However, we noticed significant bradycardia in some patients immediately after administration of bolus doses of octreotide. Therefore, we investigated the effect of intravenous octreotide on systemic hemodynamics in 59 patients with cirrhosis. In two double-blind, placebo-controlled protocols, 32 patients received a 25-μg bolus and 20 patients received an infusion of 50-μg/hr of octreotide/placebo. Immediately after the bolus dose of octreotide was administered, there were significant reductions in pulse rate (77 ± 3 vs. 65 ± 3 beats per minute, P < 0.01) and cardiac output (9.2 ± 0.8 vs. 7.9 ± 0.8 L/min; P < 0.01) and significant increases in mean arterial pressure (81 ± 3 vs. 87 ± 3 mm Hg; P < 0.05), mean pulmonary artery pressure (9.1 ± 1.0 vs. 16.6 ± 1.5 mm Hg; P < 0.01), right atrial pressure (3.8 ± 0.8 vs. 6.6 ± 1.0 mm Hg; P < 0.01), right ventricular pressure (7.1 ± 0.6 vs. 12.5 ± 1.3 mm Hg; P < 0.01), pulmonary capillary wedge pressure (4.8 ± 0.8 vs. 11.2 ± 1.4 mm Hg; P < 0.01), systemic vascular resistance, and pulmonary vascular resistance. Thirty minutes after the start of the infusion, there were significant increases in mean right atrial pressure, right ventricular pressure, pulmonary artery pressure, and pulmonary capillary wedge pressure. This study suggests that intravenous octreotide has significant effects on the systemic circulation in patients with cirrhosis and that these effects appear to be more marked after administration of bolus doses.
Bacterial and fungal infections after liver transplantation: An analysis of 284 patients
Authors: Wade Jim J. , Rolando Nancy , Hayllar Karen , Philpott-Howard John , Casewell Mark W. , Williams Roger
Published: March 2007

A prospective study of bacterial and fungal infections after liver transplantation in 284 adults was undertaken. One hundred seventy-five (62%) became infected; bacterial or fungal infections occurred in 159 (56%) and 36 (13%) patients, respectively. Gram-positive cocci, in particular Staphylococcus aureus and Enterococcus faecium, were the commonest bacterial pathogens, and bacteremia and wound infection were the most frequent bacterial infections. Acute rejection and prolonged admission were independent risk factors for bacterial infection; pretransplantation antibacterials had a protective effect. Fungal infection most frequently involved the urinary tract and chest; Candida albicans was the most common pathogen. Four independent variables predicted fungal infection: low pretransplantation hemoglobin, high pretransplantation bilirubin, return to surgery, and prolonged therapy with ciprofloxacin. Patients with acute liver failure were more prone to bacterial, but not fungal, infection. No associations were found between infections and duration of surgery. Bacterial, and to a lesser extent, fungal infections are important complications of liver transplantation. However, liver transplantation surgery per se may not be the major determinant of infection.
Immunoglobulin g lymphocytotoxic antibodies in clinical liver transplantation: Studies toward further defining their significance
Authors: Mañez Rafael , Kelly Robert H. , Kobayashi Makoto , Takaya Shunichi , Bronsther Oscar , Kramer David , Duquesnoy Rene J. , Iwaki Yuichi , Fung John J. , Starzl Thomas E. , Demetris Anthony J.
Published: March 2007

Twenty-two consecutive liver allograft recipients, who tested positive for immunoglobulin G (IgG) lympho-cytotoxicity were subjected to pretransplantion and posttransplantation immunologic monitoring of antidonor IgG lymphocytotoxic antibody titers, total hemolytic complement activity (CH100), circulating immune complexes (CIC), and platelet counts in an effort to improve our understanding of the preformed antibody state in clinical hepatic transplantation. Ten contemporaneous liver transplant recipients whose crossmatch results were negative and who experienced severe hepatocellular damage early after transplantation were included as controls. Crossmatch test results were negative 1 day after transplantation and during the 1 month follow-up remained negative in 14 of 22 (64%) sensitized recipients, most of whom had relatively low (≦ 1:16) antidonor IgG antibody titers before transplantation. After transplantation, this group and the control group experienced no thrombocytopenia, no increase of CIC, and a gradual increase in CH100 activity that reached normal levels within 1 week. A strong negative correlation between prothrombin time (PT) and CH100 activity in these groups of patients suggested that changes in CH100 activity (P < 0.0005) were tightly linked to liver synthetic function. In contrast, the crossmatch test results remained positive after transplantation in 8 of 22 (36%) sensitized recipients, all of whom had relatively high (> 1:32 to 1024) pretransplantation titers of antidonor IgG antibodies. After transplantation these patients developed a syndrome that was characterized by decreased CH100 activity and increased CIC compared with pretransplantation levels and refractory thrombocytopenia that was associated with a 50% allograft failure rate because of biopsy-proven humoral and acute (cellular) rejection. Moreover, the lack of a strong negative correlation between PT and CH100 activity (P = 0.1) in this group of patients suggested that the hypocomplementemia was not tightly linked to liver synthetic function. Before transplantation, determination of anti—donor antibody class (IgG) and titer alone showed a strong negative predictive value (100%) but less than optimal positive predictive value (67%) for identifying patients who experienced the posttransplantation syndrome described above. Therefore, evaluation of platelet counts, CH100 activity, CIC, persistence of anti-donor antibodies and results of a liver biopsy performed after transplantation assisted in identifying sensitized liver allograft recipients who suffered the adverse consequences of the preformed antibody state.
Histidinemia in mice: A metabolic defect treated using a novel approach to hepatocellular transplantation
Authors: Selden Clare , Calnan Denis , Morgan Neil , Wilcox Hervey , Carr Edward , Hodgson Humphrey J. F.
Published: March 2007

Histidinemia in mice and in humans is an autosomal recessive disorder of histidine metabolism that leads to high-histidine levels in both plasma and urine and is caused by a lack of hepatic histidine-α-deaminase (histidase). We have used a novel approach to hepatocellular transplantation to effect a complete phenotypic cure of histidinemia in a mouse model. Mice lacking histidase were treated with isolated liver cells (approximately 18 ± 106 hepatocytes and 9 ± 106 nonparenchymal cells) from histidase-competent donors transplanted into the peritoneum (active transplant group). Recipient mice showed a dramatic decrease, by more than 75%, in urinary histidine levels from day one throughout the course of the experiment, resulting in levels within the normal range for wild-type mice. In comparison, there was no change in urinary histidine levels in the control group of histidase-deficient mice treated with isolated liver cells from mice lacking histidase (statistical comparison between the two groups, P < 0.003, two-way ANOVA). Histologically, ectopic liver tissue was seen in the peritoneum in association with abdominal wall, pancreas, and peritoneal connective tissue; immunohistochemical evidence showed expression of histidase in the ectopic liver tissue in the active transplant group. This report is the first to show complete correction of a defective biochemical phenotype achieved by hepatocellular transplantation.
Hepatic fibrosis produced in guinea pigs by chronic ethanol administration and immunization with acetaldehyde adducts
Authors: Yokoyama Hirokazu , Nagata Shigeyuki , Moriya Susumu , Kato Shinzo , Ito Takashi , Kamegaya Kiyotaka , Ishii Hiromasa
Published: March 2007

Experimental hepatic fibrosis was produced in the guinea pig. We produced hepatic necrosis associated with inflammatory cell infiltration in guinea pigs immunized with acetaldehyde adducts and fed ethanol for 40 days. Extending the period of these treatments to 90 days resulted in producing hepatic fibrosis developing around individual hepatocytes in the terminal hepatic venule areas and portal areas, accompanied by an increase in hepatic hydroxyproline content. In contrast, no fibrosis was observed in the livers of the control groups that had been exposed to nothing, ethanol alone, or a combination of ethanol and immunization with unmodified human hemoglobin. Minimal fibrotic changes were observed in animals immunized with human hemoglobin acetaldehyde adducts but not fed ethanol. These results indicate that the formation of acetaldehyde adducts and the acquisition of immunity against them can produce hepatic fibrosis. Immune mechanisms against acetaldehyde adducts may, in part, be involved in the pathogenesis of hepatic fibrosis seen in alcoholics.
Mitochondrial oxidative phosphorylation and intracellular glutathione compartmentation during rat liver regeneration
Authors: Vendemiale Gianluigi , Guerrieri Ferruccio , Grattagliano Ignazio , Didonna Domenico , Muolo Leonilde , Altomare Emanuele
Published: March 2007

The rate of mitochondrial oxidative phosphorylation and the cytosolic and mitochondrial total and oxidized glutathione concentrations were studied in regenerating rat livers after partial (70%) hepatectomy. The rate of mitochondrial oxidative phosphorylation progressively decreased during the early prereplicative phase of liver regeneration. This was accompanied by a progressive decrease in mitochondrial, but not cytosolic, glutathione concentration. Twenty-four hours after partial hepatectomy, both the rate of adenosine triphosphate (ATP) synthesis and the amount of mitochondrial glutathione were depressed by 50% with respect to controls (shamoperated animals). During the second replicative phase, both the oxidative phosphorylation rate and mitochondrial glutathione concentration were recovered; however, the kinetics of the recovery were different, being the total amount of mitochondrial glutathione completely restored 48 hours after partial hepatectomy, whereas 72 hours were needed for the recovery of oxidative phosphorylation. The decrease in the rate of oxidative phosphorylation, during the early phase of liver regeneration, appeared to be secondary to the decreased content of the catalytic subunit β-F1 of the ATP synthase complex, which in turn was shown to be linearly related to the decrease of intramitochondrial glutathione. These observations suggest that the two phenomena may be due to the previously reported increased free radical production during the early phase of liver regeneration. The depression of mitochondrial glutathione after partial hepatectomy may play a contributory role in structural and functional alterations of mitochondria occurring in the first retrodifferential phase of liver regeneration.
Hormone-induced bile flow and hepatobiliary calcium fluxes are attenuated in the perfused liver of rats made cholestatic with ethynylestradiol in vivo and with phalloidin in vitro
Authors: Hamada Yuhki , Karjalainen Ari , Bygravec Fyfe L.
Published: March 2007

The actions of vasopressin and glucagon, administered alone or together, were assessed on bile flow in perfused livers from rats made cholestatic by the injection of ethynylestradiol and from those allowed to recover from such treatment. Concomitant measurements were made of biliary calcium output as well as changes in the perfusate Ca2+ concentration, glucose output, and oxygen uptake. Experiments were also conducted where cholestasis was induced in vitro in the perfused liver by the infusion of phalloidin. In each case cholestasis was demonstrated to have occurred by a reduction in bile flow by approximately 50%. The data show that the transient increase in bile flow and bile calcium seen in control rat liver soon after the administration of vasopressin, particularly when coadministered with glucagon, is largely absent in cholestasis induced by ethynylestradiol and attenuated in cholestasis induced by phalloidin. At the same time the pattern of perfusate Ca2+ fluxes in ethynylestradiol-induced cholestasis shifts to one reflecting net efflux of the ion from the liver. The responses to glucagon administration alone contrast with those of vasopressin in that in the perfused liver of ethynylestradiol-treated rats, glucagon induces a pronounced and sustained increase in bile flow. In cholestasis induced by both ethynylestradiol and phalloidin, glucagon fails to induce an initial transient decrease in bile flow. The effects of glucagon, including enhancement of vasopressin-stimulated bile flow in control and in ethynylestradiol-treated rats, can be mimicked by dibutyryl cyclic adenosine monophosphate (cAMP). Changes in glucose output and oxygen uptake induced by both hormones are only slightly attenuated. The data show that the modulation of bile flow that occurs rapidly after the administration of vasopressin and glucagon to control perfused rat liver is altered in conditions of cholestasis induced by either ethynylestradiol or phalloidin.
In situ detection of fragmented dna (tunel assay) fails to discriminate among apoptosis, necrosis, and autolytic cell death: A cautionary note
Authors: Kraupp Bettina Grasl , Ruttkay-Nedecky Branislav , Koudelka Helga , Bukowska Krystyna , Bursch Wilfried , Schulte-Hermann Rolf
Published: March 2007

Detection of DNA fragments in situ using the terminal deoxyribonucleotidyl transferase (TDT)-mediated dUTP-digoxigenin nick end labeling (TUNEL) assay is increasingly applied to investigate active cell death (apoptosis). We studied the specificity of the assay in well-defined models of apoptosis and necrosis as well as in postmortem autolysis in rat liver. During involution of liver hyperplasia, which follows stopping treatment with the hepatomitogens cyproterone acetate (CPA) or nafenopin (NAF), numerous apoptotic hepatocytes could be observed with TUNEL-positive chromatin residues. A similar TUNEL-positive reaction appeared in necrotic hepatocytes after a cytotoxic dose of carbon tetrachloride (CCl4) or N-nitrosomorpholine (NNM). Also, in insufficiently fixed, autolytic livers TUNEL-positive nuclei were observed. Thus, DNA fragmentation is common to different kinds of cell death; its detection in situ should not be considered a specific marker of apoptosis.
Quantification of hepatitis B virus DNA over a wide range from serum for studying viral replicative activity in response to treatment and in recurrent infection
Authors: Ranki Marjut , Schätzl Hermann M. , Zachoval Reinhart , Uusi-Oukari Mikko , Lehtovaara Päivi
Published: March 2007

A new standardized test for hepatitis B virus (HBV) DNA with increased sensitivity and range over previous assays (30 to 106 HBV genomes/test) was evaluated in this study. The quantitative results from the test have been validated using international reference specimens of known titer and a reference solution hybridization test. The test has small variability considering the wide dynamic range. The CV was 14% within one experiment and 32% to 39% between independent experiments. Hepatitis B surface antigen (HBsAg)-negative, anti—HBc-positive blood donor sera (n = 25) were all negative for HBV DNA in the new test, whereas 63% (n = 19) of HBsAg-positive healthy carriers had measurable quantities of HBV DNA. In five example cases of chronic hepatitis B patients responding to alfa-interferon treatment but remaining virus positive, HBV DNA was consistently present in posttreatment sera in a titer range 4 × 103 to 106/mL not detectable by the conventional hybridization test. In two complete responders, the HBV DNA titer decreased over six orders of magnitude to below cutoff of the test. In four liver transplant recipients with chronic hepatitis B, viral recurrence was detected by the new test at an early stage much before the clinical relapse. Unlike serology, the test was suitable also in patients under anti-HBs immunoprophylaxis. In conclusion, the new colorimetric polymerase chain reaction (PCR) test allowed thousandfold increased sensitivity in quantification of HBV DNA in patient sera. The test may have future applications in improving assessment of efficacy of antiviral treatment and guiding therapeutic interventions.
Deletion of integrated hepatitis B virus genome and cellular flanking sequences in hepatocellular carcinoma cells in BALB/c Mice
Authors: Chang Poa-Chun , Hu Cheng-Po , Chen Shu-Hsia , Wang-Wuu Sheng , Chang Chungming
Published: March 2007

We have previously reported the establishment of well-differentiated BALB/c mouse liver (ML) cell lines. Transfection of these cell lines with hepatitis B virus (HBV) DNA led to the expression of HBV-specific antigens and integration of HBV sequences in the cellular genome. Two cloned HBV-transfected ML cell lines, ML-2(HBV) and ML-3(HBV), expressed viral antigens and were highly tumorigenic in nude mice. However, the tumorigenicity of the two cell lines was significantly reduced in BALB/c mice. Southern blot analyses showed that the integrated HBV sequences were retained in tumors growing in nude mice but deleted in tumors growing in BALB/c mice. Furthermore, the deletion of HBV DNA was accompanied by deletion of chromosomal sequences flanking the HBV integration sites. In ML-2(HBV) cells, a significant reduction in chromosomal number was also observed. These results suggest that the immune response of BALB/c mice selected against hepatocellular carcinoma (HCC) cells expressing viral antigens and led to the proliferation of cells with deleted HBV sequences and concomitant chromosome aberrations. By using this mechanism, HCC cells escape the immune surveillance and gain the advantage of cell growth.
Hematopoietic stem cell markers are expressed by ductal plate and bile duct cells in developing human liver
Authors: Blakolmer Karin , Jaskiewicz Kasimirsz , Dunsford Harold A. , Robson Simon C.
Published: March 2007

The identification of ductal plate cells as likely progenitors for bile duct epithelium and hepatocytes and their possible reappearance as oval cells in the regenerating liver have generated much interest in their pluri-potential capacities. We have examined the distribution of three hematopoietic stem cell markers, c-kit, CD34, and CD33 in addition to laminin, the standard cytokera-tin markers CAM 5.2, CK 18, and CK 7 and the oval cell marker OV-6 in fetal liver during various stages of development. Hematopoietic stem cell markers were expressed in ductal plate cells in a pattern similar to the early cytokeratin markers CAM 5.2 and CK 18. Cells stained strongly for these early cytokeratin markers until 22 weeks. Thereafter, the expression of these markers decreased while positivity for CK 7 increased. Bile duct cells showed a distribution of hematopoietic and cytokeratin markers resembling that of ductal plate cells. Both ductal plate cells and bile duct cells expressed OV-6 strongly throughout development. This study showed similarity between hepatic and bile duct precursors and bone marrow stem cells. The comparable distribution of markers in bile duct epithelium and ductal plate cells may imply fewer transitional stages between ductal plate cells and bile duct epithelium than between the putative stem cells and hepatocytes.
Implications of host pancreatic hormones in the restart of grafted liver
Authors: Kiuchi Tetsuya , Kuse Ernst R. , Oldhafer Karl J. , Ringe Burckhardt , Okamoto Shogo , Bornscheuer Albrecht , Brabant George , Yamaoka Yoshio , Pichlmayr Rudolf
Published: March 2007

Regulatory roles of insulin and glucagon in hepatic metabolism and function are well described. However, little is known about implications of host pancreatic hormones in primary function of grafted liver. This study aimed to investigate it in relation to hepatic mitochondrial function. Insulin, c-peptide, and glucagon in peripheral blood were monitored for 2 days in clinical liver transplantation by a continuous sampling technique to avoid influences of hormonal oscillation. In grafts with immediate function (n = 10), smooth increase of arterial ketone body ratio reflecting hepatic intramitochondrial redox state was accompanied by increased c-peptide and decreased glucagon, resulting in the increase of c-peptide/glucagon ratio. In other functioning grafts (n = 20), where ketone body ratio was rather lower, increased glucagon level, observed also during anhepatic phase, resulted in the slower increase of c-peptide/glucagon ratio. These were accompanied by increased free fatty acid and ketone body levels. In primary nonfunction (n = 4), rapid increase of c-peptide accompanied by hyperglycemia resulted in the accelerated increase of c-peptide/glucagon ratio, but ketone body ratio did not show any increase. Insulin/c-peptide ratio also showed a rapid increase. These findings suggest that the increase of insulin/glucagon ratio in portal blood, potentially influenced by recipient condition, is associated with the recovery of mitochondrial energy metabolism in survived hepatic grafts. However, this relationship does not work in failed grafts, where irreversible impairment of energy metabolism is attributed to graft itself.
Noninvasive assessment of hepatobiliary and renal elimination of cysteinyl leukotrienes by positron emission tomography
Authors: Guhlmann Albrecht , Krauss Katja , Oberdorfer Franz , Siegel Thilo , Scheuber Peter H. , Müller Juliane , Csuk-Glänzer Brigitte , Ziegler Sibylle , Ostertag Hermann , Keppler Dietrich
Published: March 2007

N-Acetyl-leukotriene E4 has been identified as an endogenous, biologically less active cysteinyl leukotriene metabolite in rodents and humans. To evaluate the ratio of hepatobiliary to renal elimination of leukotrienes noninvasively by positron emission tomography (PET), we synthesized N-[11C]acetyl-leukotriene E4 by chemical N-acetylation of leukotriene E4. After the intravenous injection of N-[11C]acetyl-leukotriene E4 in normal rats and monkey, uptake by the liver and subsequent excretion into bile were largely responsible for its rapid elimination from blood. In the Cynomolgus monkey, renal excretion of the leukotriene into urine was of additional quantitative importance. Kinetic modeling indicated a mean transit time through the liver of 17 minutes and 34 minutes in rat and monkey, respectively; the corresponding hepatic excretion half-times amounted to 8.5 minutes and 16 minutes. In a mutant rat strain deficient in the hepatobiliary excretion of cysteinyl leukotrienes across the canalicular membrane, the apparent mean liver transit time was 54 minutes, and the hepatic excretion half-time was 29 minutes, indicating prolonged organ storage and metabolism. After transport from the liver back into the circulating blood of ω-oxidized and β-oxidized metabolites of N-[11C]acetyl-leukotriene E4, renal excretion compensated for the impairment of hepatobiliary elimination in the transport mutant. Metabolite analyses in urine after intravenous injection of N-[3H]acetyl-leukotriene E4 indicáted the extensive inactivation of N-acetyl-leukotriene E4 by β-oxidation from the ω-end in the mutants. A similar shift from hepatobiliary to renal cysteinyl leukotriene elimination was monitored in rats with cholestasis due to bile duct obstruction. N-[11C]Acetyl-leukotriene E4 enables the assessment of hepatobiliary function by PET as well as the quantitative and noninvasive evaluation of the contribution of liver and kidney to leukotriene elimination under normal and various pathophysiological conditions.
Protective effect of hepatocyte growth factor on interferon-gamma—induced cytotoxicity in mouse hepatocytes
Authors: Morita Masahiko , Watanabe Yoshifumi , Akaike Toshihiro
Published: March 2007

We examined the interactive effect of several cytokines (interleukin-1 beta [IL-1β], tumor necrosis factor alpha [TNF-α], interferon gamma [IFN-γ], IL-6, IFN-α/B, and hepatocyte growth factor [HGF]) presumably involved in hepatitis, on primary cultured murine hepatocytes. Among these cytokines, only IFN-γ induced LDH release from hepatocytes in both time- and dose-dependent fashions. The cytotoxic effect was inhibited by antiserum—containing anti-mouse IFN-γ monoclonal antibodies (R4-6A2). Moreover, intriguingly, IFN-γ induced DNA fragmentation in the hepatocytes in a time- and dose-dependent fashion according to the gel electrophoresis of genomic DNA and flow cytometry analysis. These results suggest that the cytotoxic effect of IFN-γ on hepatocytes was caused by inductive apoptosis. The LDH release and DNA fragmentation induced by IFN-γ were inhibited by HGF in a dose-dependent manner, whereas they seemed to be accelerated by TNF-α. Flow cytometry analysis of the nuclei of treated hepatocytes confirmed the interactions in DNA degradation. The DNA synthesis of cultured hepatocytes was also reduced by IFN-γ but recovered by hepatocyte growth factor. Taken together, IFN-γ is presumed to be a critical cytokine in hepatic damage, and the network composed of IFN-γ, TNF-α, and HGF may play an important role in the regulation of liver injury.
Modulation of experimental alcohol-induced liver disease by cytochrome P450 2E1 inhibitors
Authors: Morimoto Michio , Hagbjörk Ann-Louise , Wan Yu-Jui Yvonne , Fu Paul C. , Clot Paolo , Albano Emanuele , Ingelman-Sundberg Magnus , French Samuel W.
Published: March 2007

This study was done to determine if a relationship exists between CYP2E1 induction by ethanol, lipid peroxidation, and liver pathology in experimental alcohol-induced liver disease in the rat. Rats were fed ethanol with or without diallyl sulfide (DAS) or phenethyl isothiocyanate (PIC) intragastrically for 1 month. CYP2E1 induction by ethanol was correlated with lipid peroxidation, liver microsomal CYP2E1 hydroxylation of paranitrophenol, and the liver pathology score using the data from the PIC-fed rats. Some of the data from the ethanol and DAS-fed rats were not included here because they have been reported elsewhere. Microsomal CYP2E1 protein levels induction by ethanol was decreased by PIC ingestion. Similarly, PIC reduced the increase microsomal reduced form of nicotinamide-adenine dinucleotide (NADPH)-dependent lipid peroxidation and p-nitrophenol hydroxylase (PNPH) activity, induced by ethanol feeding. The lipid peroxidation was reduced to below control levels; however, the pathology score was partially but not significantly reduced by isothiocyanate feeding. CYP2E1 messenger RNA (mRNA) was decreased by both inhibitors of CYP2E1. Immunohistochemical staining of liver for CYP2E1 protein showed that the lobular distribution of the isozyme changed from the centrilobular to a diffuse pattern, with an increase in the periportal region when the CYP2E1 inhibitors were fed with ethanol, and that this change correlated with the change in the distribution of fat in the lobule. The data support the idea that there is a link between CYP2E1 induction by ethanol and the early phase of ethanol-induced liver injury in this rat model. This link may involve lipid peroxidation, but other factors related to CYP2E1 induction must also be involved.
Increased aortic cyclic guanosine monophosphate concentration in experimental cirrhosis in rats: Evidence for a role of nitric oxide in the pathogenesis of arterial vasodilation in cirrhosis
Authors: Niederberger Michel , Ginès Pere , Tsai Phoebe , Martin Pierre-Yves , Morris Kenneth , Weigert André , McMurtry Ivan , Schrier Robert W.
Published: March 2007

Arterial vasodilation is considered to be the key factor in the development of sodium and water retention leading to ascites formation in cirrhosis. To determine if nitric oxide (NO) is involved in the pathogenesis of arterial vasodilation in cirrhosis, we measured the concentration of cyclic guanosine monophosphate (cGMP), the second messenger of NO, in arterial tissue from rats with carbon tetrachloride—induced cirrhosis. Aortic cGMP concentration was markedly increased in cirrhotic rats, particularly in those with ascites (ascites, 826 ± 70; no ascites, 597 ± 48; controls, 331 ± 25 fmol/mg, ANOVA F = 23.1, P < 0.0001), and correlated inversely with arterial pressure (r = −.56, P < 0.0001) and systemic vascular resistance (r = −.69, P = 0.014) and directly with cardiac index (r = 0.74, P < 0.01). The chronic administration of the NO synthesis inhibitor N
G-nitro-L-arginine-methyl-ester (L-NAME) (10 mg/kg/day for 7 days) induced a marked reduction in aortic cGMP concentration in cirrhotic rats with ascites to similar values obtained in L-NAME-treated control rats (86 ± 14 vs. 89 ± 8 fmol/mg, respectively, NS), indicating that the high-aortic cGMP content in cirrhotic rats was caused by an increased NO synthesis. Mean arterial pressure after L-NAME treatment increased to similar values in both groups of animals. These results suggest that in cirrhosis there is an increased vascular production of NO that may play a role in the pathogenesis of arterial vasodilation.
Cytokine-induced upregulation of hepatic intercellular adhesion molecule-1 messenger RNA expression and its role in the pathophysiology of murine endotoxin shock and acute liver failure
Authors: Essani Naeem A. , Fisher Michael A. , Farhood Anwar , Manning Anthony M. , Smith Wayne C. , Jaeschke Hartmut
Published: March 2007

Neutrophil-induced liver injury during endotoxemia is dependent on the adhesion molecule Mac-1 (CD11b/CD18) on neutrophils. The potential involvement of its counterreceptor, intercellular adhesion molecule—1 (ICAM-1), in the pathogenesis was investigated after administration of 100 μg/kg Salmonella abortus equi endotoxin (ET) in galactosamine-sensitized mice (Gal). In ET-sensitive mice (C3Heb/FeJ), which generated large amounts of tumor necrosis factor—alpha (TNF-α), massive neutrophil infiltration and severe liver injury were observed. In an ET-resistant strain (C3H/HeJ), which did not generate TNF-α, Gal/ET failed to cause neutrophil accumulation or injury. ICAM-1 messenger RNA (mRNA), negligible in control livers, was selectively induced by Gal/ET in ET-sensitive mice. Intravenous injection of murine TNF-α, interleukin-1 alpha (IL-1α) or IL-1β (13 to 23 μg/kg) strongly induced the ICAM-1 message in both strains, showing a comparable capacity for ICAM-1 mRNA synthesis. All cytokines caused similar neutrophil accumulation in the liver; however, only Gal/TNF-α also caused upregulation of Mac-1 on circulating neutrophils and liver injury. The anti-murine ICAM-1 monoclonal antibody YN.1 (3 mg/kg) attenuated liver injury in ET-sensitive mice by 67% to 90% compared with isotype-matched control antibody-treated animals but did not reduce neutrophil accumulation in hepatic sinusoids. Our data suggest that the cytokines TNF-α and IL-1 are the main mediators responsible for upregulation of ICAM-1 mRNA in the liver during endotoxemia. The upregulation of both adhesion molecules, ICAM-1 and Mac-1, is necessary for a neutrophil-induced liver injury to occur. Blocking ICAM-1 and/or interfering with ICAM-1 induction could be a successful therapeutic strategy to prevent sepsis-related inflammatory liver injury.
Redistribution of canalicular organic anion transport activity in isolated and cultured rat hepatocytes
Authors: Roelofsen Han , Bakker Conny T. M. , Schoemaker Berry , Heijn Marc , Jansen Peter L. M. , Oude Elferink Ronald P. J.
Published: March 2007

The hepatocanalicular transport of a large number of organic anions, such as bilirubin glucuronides and glutathione conjugates in the rat, is mediated by an adenosine triphosphate (ATP)-dependent transport system, which is termed canalicular multispecific organic anion transporter (cMOAT). This system is mainly defined by its deficiency in mutant TR− rats. We have previously reported that in cultured hepatocytes the fluorescent organic anion glutathione-bimane (GS-B) accumulates in intracellular vesicles and that this transport is mediated by cMOAT. We now show that this intracellular accumulation of fluorescent organic anion is largely absent in freshly isolated hepatocytes but appears when cells are incubated in suspension at 37°C or cultured for periods of 1 to 24 hours. The appearance of intracellular cMOAT activity coincides with the disappearance of 70% of cMOAT activity from the plasma membrane as measured by the transport activity of the cells for the organic anion dinitrophenyl-glutathione (GS-DNP). Both the appearance of intracellular cMOAT and the disappearance of transport activity from the plasma membrane were completely inhibited at temperatures below 20°C. Residual cMOAT activity in 24-hour cultured hepatocytes could be further diminished by incubation of the cells with 1 μmol/L monensin or 10 mmol/L methylamine. We conclude that after disruption of the cell polarity by collagenase isolation of the hepatocytes, remnants of apical membrane containing cMOAT are rapidly endocytosed when the cells are kept at 37°C. Evidence suggests that at least part of the transporters may recycle back to the plasma membrane after endocytosis. These observations may be relevant for the understanding of regulation of canalicular transport.
Participation of small intraportal stem cells in the restitutive response of the liver to periportal necrosis induced by allyl alcohol
Authors: Yavorkovsky Leonid , Lai Eva , Ilic Zoran , Sell Stewart
Published: March 2007

To determine the involvement of different hepatocyte populations in response to periportal injury, the restitutive response to allyl alcohol (AA) injury was examined. Adult female Sprague-Dawley rats were injected intra-peritoneally (IP) with 0.62 mmol/kg AA, killed at 6, 9, 12, 33, 57, 81, and 153 hours after injection, and the livers were examined for injury and for restitutive proliferation by histology, autoradiography, and immunohisto-chemistry to detect alpha-fetoprotein (AFP), glutathi-one-s-transferase-p (GST-p), desmin, leukocyte common antigen, albumin, and monoclonal antibodies to liver cells: OV-6, H-4, and T-6. AA produces variable periportal liver necrosis predominantly at 6 to 12 hours. Proliferation of hepatocytes throughout the hepatic cord is seen early after injury in nonnecrotic areas: predominantly in zone II, but also in zones I and III, including some cells adjacent to the central vein. Within 2 to 3 days the necrotic zones are filled with small cells and by 1 week the liver architecture is essentially restored. During the active restitutive reaction from the immediate periportal rim the following cell phenotypes are seen: null cells: ± (AFP+, OV-6-, GST-p—) cells ± (AFP—, OV-6+, GST-p+) cells →large (AFP—, OV-6-, GST-p—, H-4+) liver cells. Albumin staining was negative. We conclude that restitutive proliferation of periportal necrosis induced by AA appears to be accomplished by proliferation of intraportal (?stem) cells whose progeny differentiate and eventually repopulate the necrotic zone.
Prostanoid secretion by rat hepatic sinusoidal endothelial cells and its regulation by exogenous adenosine triphosphate
Authors: Hashimoto Naoaki , Watanabe Tsuyoshi , Shiratori Yasushi , Ikeda Yusei , Kato Hirokazu , Han Katsuken , Yamada Haruki , Toda Gotaro , Kurokawa Kiyoshi
Published: March 2007

We investigated the secretory profiles of prostanoids in two types of nonparenchymal cell from the rat liver, sinusoidal endothelial cells and Kupffer cells, in primary culture both under basal conditions and after stimulation with adenine nucleotides. Prostaglandin (PG) E2 was the main prostanoid secreted by both types of hepatic nonparenchymal cell in the basal and adenosine triphosphate (ATP)-stimulated states. Time- and concentration-dependent effects of ATP-mediated PGE2 secretion were noted in sinusoidal endothelial cells, whereas the profile of the relative potencies of individual nucleotides was consistent with the presence of P2y and P1 purinergic receptors. In Kupffer cells, the regulation of prostanoid secretion by adenine nucleotides was essentially the same as that in sinusoidal endothelial cells except that adenosine did not stimulate prostanoid secretion and that prostanoid secretion differed somewhat; Kupffer cells secreted relatively more PGF2α and less 6-keto-PGF1α than sinusoidal endothelial cells in the presence of ATP, suggesting the presence of only P2y receptors. In summary, PGE2 is the main prostanoid secreted by hepatic nonparenchymal cells and its secretion may be stimulated by adenine nucleotides and adenosine.
Nonalcoholic steatohepatitis: Tightening the morphological screws on a hepatic rambler
Authors: Lee Randall G.
Published: March 2007

Background/Aims:

In the past, nonalcoholic steatohepatitis has been described mostly in obese women with diabetes. The aim of this study was to describe a series of patients with nonalcoholic steatohepatitis with a different clinical profile.

Methods:

The clinical, biochemical, and histological features of 33 patients with nonalcoholic steatohepatitis seen from July 1990 to June 1993 were analyzed.

Results:

The mean age was 47 years. All patients were antibody to hepatitis C virus-negative. Nineteen of 33 (58%) were men, 20 of 33 (61%) were non-obese, 26 of 33 (79%) had normal glucose levels, and 26 of 33 (79%) had normal lipid levels. Fourteen of 33 (42%) had normal glucose and lipid levels and were not obese. Thirteen of 33 (39%) had pathological increases in fibrosis, 5 of whom had micronodular cirrhosis. Of these 13 with severe, progressive disease, 8 (62%) were women, 8 (62%) were obese, 4 (31%) were diabetic or had an elevated glucose level, and 3 (23%) had hyperlipidemia. Although serum iron studies (transferrin saturation and ferritin) were abnormal in 18 of 31 (58%), no patient had hemochromatosis.

Conclusions:

Nonalcoholic steatohepatitis can be a severe, progressive liver disease leading to the development of cirrhosis. It should no longer be considered a disease predominantly seen in obese women with diabetes.
A comparison of the surgical results in patients with hepatitis B versus hepatitis C-related hepatocellular carcinoma
Authors: Takenaka Kenji , Yamamoto Kazuharu , Taketomi Akinobu , Itasaka Hidetoshi , Adachi Eisuke , Shirabe Ken , Nishizaki Takashi , Yanaga Katsuhiko , Sugimachi Keizo
Published: March 2007

To assess the differences in the surgical results between patients with hepatitis B- and hepatitis C-related hepatocellular carcinoma (HCC), the operative outcomes of 30 patients with hepatitis B surface antigen (HBsAg)-positive (the B-HCC group) and 96 patients with hepatitis C antibody (HCVAb)-positive (the C-HCC group), who had undergone hepatic resection from 1989 to 1993, were compared. The mean age of the patients in the C-HCC group was higher than that in the B-HCC group (61.7 years vs. 57.0 years, P < .05). The C-HCC group demonstrated both a greater decrease in liver function and a larger enhancement of inflammatory changes in the liver under a pathological examination (the current rate of active hepatitis: 69% vs. 27%, P < .001). There was also a higher incidence of total postoperative complications in the C-HCC group (60% vs. 37%, P < .05); however, regarding each individual complication, the rate was similar between the two groups. Two of the six patients with postoperative hepatic failure in the C-HCC group died. The mortality rate in the C-HCC group was 2%, but no operative death was encountered in the B-HCC group. The crude survival and the disease-free survival rates at 5 years were similar, 61.8% and 46.2% in the B-HCC group and 52.8% and 23.2% in the C-HCC group, respectively. The patterns of recurrence were also similar in both groups. The pathological features of HCC were similar between the two groups. In conclusion, the surgical results between the two groups were almost identical. However, because of the reduced liver function along with the enhancement of inflammatory changes in the liver, surgeons should therefore be more careful when determining operative indications and conducting the follow-up after surgery, especially for the C-HCC patients. (Hepatology 1995;22:20-24.)