Inhibition of matrix metalloproteinases blocks lethal hepatitis and apoptosis induced by tumor necrosis factor and allows safe antitumor therapy

Acute and fulminant liver failure induced by viral hepatitis, alcohol or other hepatotoxic drugs, are associated with tumor necrosis factor (TNF) production. In a mouse model of lethal hepatitis induced by TNF, apoptosis and necrosis of hepatocytes, but also lethality, hypothermia and influx of leukocytes into the liver, are prevented by a broad-spectrum matrix metalloproteinase (MMP) inhibitor, BB-94. Mice deficient in MMP-2, MMP-3 or MMP-9 had lower levels of apoptosis and necrosis of hepatocytes, and better survival. We found induction of MMP-9 activity and fibronectin degradation. Our findings suggest that several MMPs play a critical role in acute, fulminant hepatitis by degrading the extracellular matrix and allowing massive leukocyte influx in the liver. BB-94 also prevented lethality in TNF/interferon-gamma therapy in tumor-bearing mice. A broad-spectrum MMP inhibitor may be potentially useful for the treatment of patients with acute and perhaps chronic liver failure, and in cancer therapies using inflammatory cytokines.

Neutralization of interferon-gamma in neonatal SOCS1-/- mice prevents fatty degeneration of the liver but not subsequent fatal inflammatory disease

Mice lacking the suppressor of cytokine signalling-1 (SOCS1) die within weeks of birth with extensive fatty degeneration of the liver, consistent with acute hepatic toxicity to interferon-gamma (IFN-gamma), and inflammation of multiple organs. We show here that treatment for 1 week from birth with neutralizing antibody to IFN-gamma rescues SOCS1-/- mice from lethal liver disease but the mice subsequently succumb to chronic inflammatory lesions characterized by T-lymphocyte infiltration of skeletal muscle, pancreas, lung, liver and skin. Elevated blood levels of eosinophils, neutrophils and platelets were also observed and the thymic lymphocyte population was depleted of CD4+ CD8+ T cells and showed a reduced CD4 : CD8 ratio. All T-cell populations in thymus, spleen and lymph node exhibited an increased proportion of cells bearing the activation marker CD44. These data suggest an important role for SOCS1 in T-lymphocyte regulation.

Hypercholesterolemia exacerbates virus-induced immunopathologic liver disease via suppression of antiviral cytotoxic T cell responses

The immune system has to be optimally balanced to be highly effective against infections with cytopathic microbial pathogens and must guarantee efficient destruction of cells infected with noncytopathic agents while leaving the integrity of noninfected cells largely unaltered. We describe here the effects of genetically induced hypercholesterolemia on cellular immunity in apolipoprotein E (ApoE(-/-)) and low density lipoprotein receptor-deficient (LDLR(-/-)) mice during infection with the hepatotropic lymphocytic choriomeningitis virus WE strain. In both ApoE(-/-) and LDLR(-/-) mice hypercholesterolemia aggravated virus-induced immunopathologic liver disease. ApoE(-/-) mice exhibited a higher susceptibility to virus-induced immunopathology than LDLR(-/-) mice and usually succumbed to immunopathologic disease when infected with high doses of virus. Initial virus spread was not influenced by the hypercholesterolemia, whereas clearance of the virus from spleen and nonlymphoid organs, including liver, was delayed. Activation of antiviral CTL, measured by ex vivo cytotoxicity and IFN-gamma production, and recruitment of specific CTL into blood and liver were impaired in hypercholesterolemic mice, indicating that hypercholesterolemia had a significant suppressive effect on cellular immunity. Taken together, these data provide evidence that hypercholesterolemia suppresses antiviral immune responses, thereby changing the host-virus balance, and can increase susceptibility to acute or chronic and potentially lethal virus-induced immunopathologic disease. These findings impinge on our understanding of hypercholesterolemia as a disease parameter and may explain aspects of the frequent association of persistent pathogens with hypercholesterolemia-induced diseases, such as atherosclerosis.

In vivo evidence for accelerated generation of hydroxyl radicals in liver of Long-Evans Cinnamon (LEC) rats with acute hepatitis

The Long-Evans Cinnamon (LEC) rats accumulate excess copper (Cu) in the liver in a manner similar to patients with Wilson's disease (WD) and spontaneously develop acute hepatitis with severe jaundice. Although hydroxyl radicals (*OH) have been proposed to be a cause of hepatitis by the accumulation of Cu, it is not clear whether or not *OH can be produced in the liver of hepatitic LEC rats in vivo and also can be involved in the onset of hepatitis. In the present study, *OH production in plasma and liver of hepatitic LEC rats was quantified by trapping *OH with salicylic acid (SA) as 2, 3-dihydroxybenzoic acid (2, 3-DHBA). The ratios of 2, 3-DHBA/SA were significantly higher in plasma and liver of hepatitic LEC rats than those of Wistar rats and LEC rats showing no signs of hepatitis. Furthermore, the ratios of 2, 3-DHBA/SA in plasma and liver of hepatitic LEC rats were almost the same as those of Wistar rats treated orally with CuSO(4) (0.5 mmol/kg) 2 h before acetylsalicylic acid (ASA) injection. We also evaluated the protective effects of D-mannitol (a *OH scavenger) treatment against acute hepatitis in LEC rats. D-mannitol (500 mg/kg) was administered intraperitoneally to 10-week-old LEC rats for 3 weeks. D-mannitol treatment suppressed the increases in serum aspartate aminotransferase activity and total bilirubin concentration. In addition, D-mannitol treatment significantly reduced hepatic mitochondrial lipid peroxidation, which is thought to be important in the pathogenesis of Cu-induced hepatotoxicity. These observations suggest that accelerated generation of *OH catalyzed by free Cu in the liver may, at least in part, play a role in the pathogenesis of acute hepatitis in LEC rats.

Inhibition of anti-Fas antibody-induced mice hepatitis by furocoumarin derivatives

The effects of imperatorin and its synthetic derivative, Y355, on anti-Fas antibody-induced mice hepatitis were studied. Pretreatment of mice by intraperitoneal administration of imperatorine or Y355 at 30 mg/kg inhibited more than 80% of the anti-Fas antibody (150 microg/kg, i.v.)-induced elevation of plasma alanine aminotransferase activity. Furthermore, oral administration of imperatorin or Y355 at 100 mg/kg also had an inhibitory effect on anti-Fas antibody-induced hepatitis. Both compounds inhibited anti-Fas antibody (250 microg/kg)-induced caspase-1 and caspase-3 activities. The present results showed the inhibition of anti-Fas antibody-induced hepatitis by imperatorin and Y355, which might be a result of inhibition of caspase activities.

Inhibition of concanavalin A-induced mice hepatitis by coumarin derivatives

The effects of coumarin derivatives, osthole, imperatorin, Pd-Ia, Pd-II and Pd-III, on mice concanavalin A (Con A) (0.2 mg/mouse, i.v.)-induced hepatitis were studied. At the dose of 200 mg/kg (i.p.), these coumarins inhibited more than 90% of the Con A-induced elevation of plasma alanine aminotransferase activity, but glycyrrhizin (200 mg/kg, i.p.) caused only 45% inhibition. At the dose of 100 mg/kg (i.p.), osthole produced the strongest inhibition among these coumarins. The inhibitory activity of osthole is lost when its 7-methoxy group is replaced by a 7-hydroxy group to form osthenol. The present results showed that coumarin derivatives inhibited Con A-induced hepatitis, with osthole being the most inhibitory.

Reduction of liver Fas expression by an antisense oligonucleotide protects mice from fulminant hepatitis

Aberrant apoptosis-mediated cell death is believed to result in a number of different human diseases. For example, excessive apoptosis in the liver can result in fulminant and autoimmune forms of hepatitis. We have explored the possibility that inhibition of Fas expression in mice would reduce the severity of fulminant hepatitis. To do this, we have developed a chemically modified 2'-O-(2-methoxy)ethyl antisense oligonucleotide (ISIS 22023) inhibitor of mouse Fas expression. In tissue culture, this oligonucleotide induced a reduction in Fas mRNA expression that was both concentration- and sequence-specific. In Balb/c mice, dosing with ISIS 22023 reduced Fas mRNA and protein expressions in liver by 90%. The ID50 for this response was 8-10 mg kg-1 daily dosing, and the reduction was highly dependent on oligonucleotide sequence, oligonucleotide concentration in liver, and treatment time. Pretreatment with ISIS 22023 completely protected mice from fulminant hepatitis induced by agonistic Fas antibody, by a mechanism entirely consistent with an oligonucleotide antisense mechanism of action. In addition, oligonucleotide-mediated suppression of Fas expression reduced the severity of acetaminophen-mediated fulminant hepatitis, but was without effect on concanavalin A-mediated hepatitis. Our results demonstrate that 2'-O-(2-methoxy)ethyl containing antisense oligonucleotides targeting Fas can exert in vivo pharmacological activity in liver, and suggest that oligonucleotide inhibitors of Fas may be useful in the treatment of human liver disease.

Hepatoprotective effects of Inula britannica on hepatic injury in mice

Inula britannica, a Kampo medicine, is prepared from the heads of Compositae plants such as Inula britannica L., which has been used clinically as a remedy for nausea, hiccup and excessive sputum. Here it is shown that administration of Inula britannica improves the survival rate of mice with hepatic injury induced by LPS/PA. It is also suggested that administration of Inula britannica significantly reduces the fluctuation in the amount of cytokine in the spleen of mice with hepatic injuries, and that the Th1/Th2 control effect is related to the inhibitory action of Inula britannica against hepatic injury. In vitro testing suggests that Inula britannica suppresses Th1 differentiation and induces Th2 differentiation by inhibiting the production of macrophage IL-12 and promoting the production of IL-10, thus showing the immunological effect of hepatic injury inhibition by affecting the balance between Th1 and Th2.

A novel murine anti-human Fas mAb which mitigates lymphadenopathy without hepatotoxicity

Defects in Fas-mediated apoptosis are implicated in autoimmune diseases including rheumatoid arthritis (RA). Although induction of Fas-mediated apoptosis could have therapeutic effects on these diseases, it might cause deleterious effects in liver as Fas ligand or an agonistic anti-murine Fas antibody Jo2 causes severe hepatic injury in mice. We report here on the interesting characteristics of the newly obtained anti-Fas mAb, HFE7A, which cross-reacts with the Fas molecules of various species ranging from human to mouse and mitigates autoimmune symptoms without hepatotoxicity in mice. The administration of HFE7A to mice induced apoptosis in the thymocytes, although administration of HFE7A to mice or to marmosets did not induce any sign of hepatitis. The effect of HFE7A on liver is different from that of anti-murine Fas antibody Jo2, which causes acute and lethal hepatic injury to mice. Administration of HFE7A reduced lymphadenopathy and abnormal T cells in MRL-gld/gld mice. HFE7A induced apoptosis in synovial cells prepared from RA patients. Surprisingly, HFE7A protected mice from fulminant hepatitis induced by Jo2. Therefore, HFE7A is a potential therapeutic antibody not only for autoimmune diseases including RA but also for fulminant hepatitis.

Protective effects of soyasapogenol A on liver injury mediated by immune response in a concanavalin A-induced hepatitis model

The present study was carried out to analyze the effects of soyasapogenol A on the liver injury mediated by the immune response in concanavalin A-induced hepatitis in mice. Soyasapogenol A reduced the number of infiltrating inflammatory cells in the liver and significantly lowered the elevated level of plasma tumor necrosis factor-alpha (TNF-alpha) 2 h after concanavalin A treatment, and then markedly reduced the elevated plasma alanine aminotransferase activity and decreased the number of apoptotic bodies in the liver parenchymal cells but not in the sinusoidal cells at 24 h. Since the effect of soyasapogenol A on the elevated plasma TNF-alpha level was not appreciable compared to the preventive effect of soyasapogenol A on the elevated plasma alanine aminotransferase level, these results suggest that soyasapogenol A directly prevents apoptosis of hepatocytes, and secondly, inhibits the elevation of plasma TNF-alpha, which consequently resulted in the prevention of liver damage in the concanavalin A-induced hepatitis model.

Dissolution of copper-rich granules in hepatic lysosomes by D-penicillamine prevents the development of fulminant hepatitis in Long-Evans cinnamon rats

BACKGROUND/AIM

The Long-Evans cinnamon rat has a mutation homologous to the human Wilson disease gene, leading to gross copper accumulation and the development of hepatitis. D-penicillamine, a copper-chelating drug widely and efficiently used in treating Wilson disease, has also been shown to prevent hepatitis in Long-Evans cinnamon rats. The objectives of this study were: i) to investigate the effectiveness of D-penicillamine when administered to the already affected animals, and ii) to elucidate the mechanism of action of the drug.

METHODS

Long-Evans cinnamon rats were divided into groups according to age and treatment with D-penicillamine. The drug was administered orally before and after the onset of hepatitis. Livers were examined by light and electron microscopy. The effect of D-penicillamine on the subcellular distribution and binding of copper was investigated in more detail. Finally, the interaction between D-penicillamine and specific hepatic copper-binding proteins was studied in vitro.

RESULTS

D-penicillamine when given to either healthy or diseased animals prevented or reversed hepatitis, respectively. The drug particularly inhibited the disease-specific accumulation of copper in lysosomes of hepatocytes, tissue macrophages and Kupffer cells. When administered to diseased animals, the drug sequestered copper particularly from insoluble lysosomal particles. According to results obtained in vitro, the mobilization of this copper is likely to proceed through the solubilization of these particles. In contrast and as supported by the in vitro data, D-penicillamine had only a minor effect on copper bound to metallothionein in the cytosol.

CONCLUSION

Our findings on the Long-Evans cinnamon rat provide some conclusions on the mechanism of action of D-penicillamine in Wilson disease therapy. The drug prevents the formation or promotes the solubilization of copper-rich particles which occur in lysosomes of hepatocytes and Kupffer cells in the livers of patients with Wilson disease. Once chelated with D-penicillamine copper might then be excreted into urine. However, the mobilization of copper by D-penicillamine seems to be limited due to the binding of the metal to metallothionein in liver cytosol. This copper, even at relatively high concentrations, apparently may be well tolerated.

The protective effect of glycyrrhizin on anti-Fas antibody-induced hepatitis in mice

Fas ligand, which is a type II membrane protein, is a major inducer of apoptosis. The effect of glycyrrhizin on anti-Fas antibody-induced hepatitis in mice was studied. Pretreatment of mice with glycyrrhizin (100, 200 and 400 mg/kg, i.p.) inhibited the anti-Fas antibody (150 microg/kg, i.v.)-induced elevation of plasma aminotransferase activity in a dose-dependent manner. CPP32 is a cystein protease and CPP32-like activity induced by anti-Fas antibody injection was inhibited by glycyrrhizin (200 mg/kg). However, the addition of glycyrrhizin (up to 10(-4) M) to a liver cytosol fraction isolated from mice treated with anti-Fas antibodies (150 microg/kg, i.v.) did not inhibit the CPP32-like activity in vitro. The present results clearly show that glycyrrhizin inhibited anti-Fas antibody-induced hepatitis by acting upstream of CPP32-like protease activation.

Activation of caspases in lethal experimental hepatitis and prevention by acute phase proteins

Lethal hepatitis can be induced by an agonistic anti-Fas Ab in normal mice or by TNF in mice sensitized to d -(+)-galactosamine or actinomycin D. In all three models, we found that apoptosis of hepatocytes is an early and necessary step to cause lethality. In the three models, we observed activation of the major executioner caspases-3 and -7. Two acute-phase proteins, alpha1-acid glycoprotein and alpha1-antitrypsin, differentially prevent lethality: alpha1-acid glycoprotein protects in both TNF models and not in the anti-Fas model, while alpha1-antitrypsin confers protection in the TNF/d -(+)-galactosamine model only. The protection is inversely correlated with activation of caspase-3 and caspase-7. The data suggest that activation of caspase-3 and -7 is essential in the in vivo induction of apoptosis leading to lethal hepatitis and that acute phase proteins are powerful inhibitors of apoptosis and caspase activation. Furthermore, Bcl-2 transgenic mice, expressing Bcl-2 specifically in hepatocytes, are protected against a lethal challenge with anti-Fas or with TNF/d -(+)-galactosamine, but not against TNF/actinomycin D. The acute-phase proteins might constitute an inducible anti-apoptotic protective system, which in pathology or disturbed homeostasis prevents excessive apoptosis.

Glycyrrhizin protects mice from concanavalin A-induced hepatitis without affecting cytokine expression

The administration of concanavalin A (Con A) to mice induces cytokine-dependent hepatitis. In the present study, the effect of glycyrrhizin on Con A-induced hepatitis was examined. Treatment of mice with Con A (0.2 mg/mouse, i.v.) induced elevation of the plasma transaminase activities at 24 h. Mice were treated with glycyrrhizin (100, 200 and 400 mg/kg, i.p.), and glycyrrhizin at the doses of 200 and 400 mg/kg inhibited the Con A-induced elevation of the plasma transaminase activities. At 1 h after Con A treatment, interferon-gamma, tumor necrosis factor-alpha, interleukin-2 and interleukin-6 proteins were released into the plasma. Although treatment with glycyrrhizin at 200 mg/kg inhibited Con A-induced hepatitis, it did not affect the release of any of these Con A-induced cytokines into the plasma. The present results clearly show that glycyrrhizin inhibited Con A-induced hepatitis without affecting cytokine expression.

Active participation of CCR5(+)CD8(+) T lymphocytes in the pathogenesis of liver injury in graft-versus-host disease

We examined the molecular pathogenesis of graft-versus-host disease-associated (GVHD-associated) liver injury in mice, focusing on the role of chemokines. At the second week after cell transfer in the parent-into-F1 model of GVHD, CD8(+) T cells -- especially donor-derived CD8(+) T cells -- infiltrated the liver, causing both portal hepatitis and nonsuppurative destructive cholangitis (NSDC). These migrating cells expressed CCR5. Moreover, macrophage inflammatory protein-1alpha (MIP-1alpha), one of the ligands for CCR5, was selectively expressed on intralobular bile duct epithelial cells, endothelial cells, and infiltrating macrophages and lymphocytes. Administration of anti-CCR5 antibody dramatically reduced the infiltration of CCR5(+)CD8(+) T lymphocytes into the liver, and consequently protected against liver damage in GVHD. The levels of Fas ligand (FasL) mRNA expression in the liver were also decreased by anti-CCR5 antibody treatment. Anti-MIP-1alpha antibody treatment also reduced liver injury. These results suggest that MIP-1alpha-induced migration of CCR5-expressing CD8(+) T cells into the portal areas of the liver plays a significant role in causing liver injury in GVHD; thus, CCR5 and its ligand may be the novel target molecules of therapeutic intervention of hepatic GVHD.

Effects of various kinds of dietary amino acids on the hepatotoxic action of D-galactosamine in rats

The protective effects of various kinds of dietary amino acids against the hepatotoxic action of D-galactosamine (GalN) were examined. Male Wistar rats fed with 20% casein diets containing 10% or 5% amino acid for one week were injected with GalN (800 mg/kg body weight), and the serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) activities, the hepatic glycogen concentration, and the serum glucose-level were examined 20 hours after the injection. In the groups with the 10% amino acid diets, activities of AST, ALT, and LDH in serum of 10% L-glutamine (Gln), 10% L-asparagine (Asn), and 10% L-serine (Ser) groups were significantly lower than those of the control group, and in the groups with the 5% amino acid diets, those activities of 5% L-histidine (His), 5% L-tyrosine (Tyr), 5% L-lysine (Lys), and 5% L-glycine (Gly) groups were also lower than those of the control group. The concentration of liver glycogen of 10% Gln-, 10% Asn-, and 10% Ser- groups and those levels of 5% His-, 5% Tyr-, 5% Lys-, and 5% Gly-groups were also significantly higher than that of the control group. As a result, it was found that some kinds of dietary amino acid such as L-Ser, L-Asn, L-His, L-Lys, L-Tyr, and L-Gly, in addition to L-Gln were effective to protect the rats from GalN-induced injury.

Preventive effect of zinc compounds, polaprezinc and zinc acetate against the onset of hepatitis in Long-Evans Cinnamon rat

It is known that Long-Evans Cinnamon (LEC) rats are characterized by the fulminant hepatitis occurring as a result of an abnormal hepatic deposition of Cu due to the lack of the Cu-transporter p-type ATPase. To prevent the hepatitis, two Zn compounds, Zn acetate and polaprezinc were given orally to LEC rats aged 30 days. At 100 days after birth, the control group composed of LEC rats fed a basal diet (Cu, 17 ppm; Zn, 50 ppm; Fe, 150 ppm) exhibited slight jaundice and showed high activities of serum enzymes related to hepatic function. The groups fed the diet fortified (1000 ppm as Zn) with Zn acetate or polaprezinc did not have jaundice. The hepatic Cu concentrations were 174 +/- 34 micrograms/g and 156 +/- 23 micrograms/g in the polaplezinc group and Zn acetate group, respectively. The control group showed 267 +/- 17 micrograms Cu/g and 298 +/- 62 micrograms Fe/g in the liver. The Fe concentration was about 1.7 times the concentration in the two Zn groups. Hepatic free Cu and Fe concentrations were 2.6 +/- 0.3 and 21.4 +/- 5.8 micrograms/g, 1.7 +/- 0.7 and 6.8 +/- 1.1 micrograms/g, and 1.3 +/- 0.1 and 6.2 +/- 0.8 micrograms/g in the control, polaprezinc and zinc acetate groups, respectively. Intestinal metallothionein (MT) concentrations were not increased significantly by the Zn diets. The two Zn compounds inhibit Cu absorption from the intestinal tract, resulting in a decrease of hepatic Cu deposition. The new Zn compound as well as Zn acetate is categorized as a therapeutic drug for Cu poisoning, including Wilson's disease.

[Comparative study of the effects of essentiale and the novel Russian hepatoprotective agent "phospholiv" in a model of acute hepatitis in rats]

Curative effect of new preparation "Phospholiv", elaborated in Institute of Biomedical Chemistry, in acute CCl4 induced rat hepatit model was studied. The preparation consists of polyunsaturated phosphatidylcholine and glycyrrhizinic acid salt. Recovery of damaged biosynthesis of albumin and total cell liver RNA--by incorporation of C14-leucine and C14-orotic acid--were observed after 3 days Phospholiv administration, that showed on reparation of damaged protein-synthesis system. Label incorporation into liver fraction > 80S--that was decreased under CCl4 influence--was also restored after Phospholiv treatment, that may testify on its regenerative effect on wholeness of subcellular hepatocytes structures. Substantial decrease of morphologic damages of liver tissue was demonstrated as well. Other phospholipid preparation--known hepatoprotector Essentiale--gave some positive effects too, but Phospholiv influence on biochemical and morphological liver features were 1.5-2 fold as compared with that of Essentiale. Results show on efficiency of polyunsaturated phospholipids in the treatment of acute hepatit in rats--as a result of influence on hepatocytes cell membrane--and on preferential effect of new hepatoprotector Phospholiv.

High-level constitutive expression of alpha 1-acid glycoprotein and lack of protection against tumor necrosis factor-induced lethal shock in transgenic mice

alpha 1-Acid glycoprotein (AGP) is an acute phase protein produced by hepatocytes. Although its exact biological function remains controversial, it was shown to protect galactosamine-sensitized or normal mice against hepatitis and lethal shock induced by tumor necrosis factor (TNF). Rat-AGP-transgenic mice, constitutively producing several mg AGP per ml serum were tested for their response to a combined challenge with TNF and D-(+)-galactosamine. A previously characterized, single transgenic line (9.5-5) was used. In contrast to our expectations both heterozygous or homozygous transgenic mice were not protected by the endogenously overproduced AGP. However, both transgenic and non-transgenic mice were protected by pretreatment with interleukin-1, an effect which we believe is mediated by the induction of acute phase proteins like AGP. Furthermore, both types of mice were protected by exogenous bovine AGP, suggesting that the lack of protection by endogenous AGP is not because of a repressed response to AGP. Finally, we demonstrate that purified AGP from the serum of transgenic mice is as protective as the AGP from non-transgenic mice or rats. The results suggest that AGP is protective only when its concentration is rapidly induced, perhaps because the endogenous steady state synthesis of AGP, in non-transgenic as well as transgenic mice, is coupled to the production of an AGP-binding factor. This study provides an interesting example of differences in outcome to a lethal challenge between an acute administered and a chronically produced protective protein.

[Use of a novel hepato-protective preparation "phospholiv" for inhibition of development of chronic hepatitis in rats]

Protective influence of a new phospholipid preparation "Phospholiv" was studied using a model of chronic hepatitis. Animals were treated 45 days intraperitoneay with CCl4 with parallel intragastral administration of Phospholiv or--(for comparison)--the of other phospholipid hepatoprotector, Essential. Morphologic changes of liver, as well as protein and RNA biosynthesis were evaluated in the end of experiment--by means of measuring C14-leucine and C14-orotic acid incorporation into hepatocyte subcellular fractions. Both phospholipid preparations attenuated dystrophic liver changes, Phospholiv effect being more pronounced. They both prevented CCl4 induced inhibition of label incorporation into subcellular fraction proteins, but only Phospholiv, promoted the maintaining normal level of radioactivity incorporation into cytosol proteins and hepatocyte RNA. The results, confirming certain protective effect of Essential, show more pronounced hepatoprotective action of the new preparation Phospholiv (developed on the basis of polyunsaturated phosphatidylcholine and glycyrrhizinic acid salt). Data show also on possible fit hepatitis treatment.

Pentoxifylline prevents concanavalin A-induced hepatitis by reducing tumor necrosis factor alpha levels and inhibiting adhesion of T lymphocytes to extracellular matrix

BACKGROUND/AIMS

Concanavalin A activates T lymphocytes and causes T cell-mediated hepatic injury in mice. Tumor necrosis factor alpha is a critical mediator in this experimental model. T-cell-mediated liver injury involves the migration of immune cells, notably CD4+ T lymphocytes, into liver tissue. Pentoxifylline is a strong suppressor of tumor necrosis factor alpha release and prevents leukocyte adherence to vascular endothelium and down-regulates the expression of intercellular adhesion molecule-1 in monocytes. In this study, we examined the efficacy of pentoxifylline as a potential therapeutic compound for the treatment of concanavalin A hepatitis.

METHODS

Balb/c mice were injected with 12 mg/kg concanavalin A with or without a single injection of pentoxifylline (5-300 mg/kg), 2 h prior to concanavalin A administration. Liver damage was evaluated by determining serum levels of liver enzymes and tumor necrosis factor alpha, and hepatic histopathology compared to mice treated with concanavalin A only. We also assessed the effects of pentoxifylline on the adhesive properties of T lymphocytes to fibronectin, as a paradigm for immune cell-extracellular matrix interactions required for migration. Pretreatment with pentoxifylline significantly reduced serum levels of liver enzymes (3800+/-650 vs 150+/-28 IU/l) and tumor necrosis factor alpha (710+/-105 vs 113+/-15 pg/ml) with no evidence of inflammation in histopathologic examination compared to control mice treated with concanavalin A. Pentoxifylline also inhibited the binding of murine T cells to fibronectin. All the effects of pentoxifylline were dose-dependent.

CONCLUSIONS

These results indicate that high doses of pentoxifylline can prevent concanavalin A hepatitis by suppression of tumor necrosis factor alpha release and inhibition of T cells adhesion to extracellular matrix.

Antibodies to tumor necrosis factor alfa attenuate hepatic necrosis and inflammation caused by chronic exposure to ethanol in the rat

Tumor necrosis factor (TNF)alpha, a pivotal cytokine involved in inflammation, is produced primarily by Kupffer cells in the liver. It has been shown that inactivation of Kupffer cells prevents alcohol-induced liver injury; therefore, the purpose of this study was to determine if neutralizing anti-TNF-alpha antibody is also effective. Male Wistar rats were exposed to ethanol (11 to 12 g x kg(-1) x d[-1]) continuously for up to 4 weeks via intragastric feeding using an enteral feeding model. Before ethanol exposure, polyclonal anti-mouse TNF-alpha rabbit serum was injected (2.0 mg/kg intravenously). There were no significant differences in body weight, mean ethanol concentration, or cyclic patterns of ethanol in urine when ethanol- and ethanol plus antibody-treated groups were compared. Expression of TNF-alpha and macrophage inflammatory protein 2 (MIP-2) messenger RNA (mRNA), determined using reverse transcription-polymerase chain reaction, was three- to four-fold higher in livers of ethanol-treated rats than in those of rats fed an ethanol-free, high-fat control diet. In addition, MIP-2 levels were also elevated when detected by Northern blot analysis. Anti-TNF-alpha antibody did not affect expression of mRNA for interleukin (IL) 1alpha, IL-6, transforming growth factor beta1, or TNF-alpha. However, MIP-2 mRNA expression, which is regulated by TNF-alpha, was decreased significantly by anti-TNF-alpha antibody treatment. Serum aspartate transaminase levels were elevated in ethanol-treated rats to 136 +/- 12 IU/L after 4 weeks but only reached 90 +/- 5 IU/L (P < .05) in rats treated with anti-TNF-alpha antibody. The hepatic inflammation and necrosis observed in ethanol-fed rats were attenuated significantly by antibody treatment, and steatosis was not. These results support the hypothesis that TNF-alpha plays an important role in inflammation and necrosis in alcohol-induced liver injury and that treatment with anti-TNF-alpha antibody may be therapeutically useful in this disease.

Contribution of Fas ligand to T cell-mediated hepatic injury in mice

BACKGROUND & AIMS

Fas has been implicated in liver damage. The aim of this study was to investigate the role of its ligand to induce hepatocyte death and liver damage in T cell-dependent hepatitis.

METHODS

Fas ligand-mediated lysis of primary hepatocytes from C57BL/6 wild-type, Fas ligand-deficient gld, and Fas-deficient lpr mice and concanavalin A-induced hepatitis in these mice were assessed.

RESULTS

Freshly isolated hepatocytes from wild-type or gld mice, but not those from lpr mice, were susceptible to Fas ligand-mediated lysis. When concanavalin A was intravenously administered into wild-type mice, they developed acute hepatic injury with massive degenerative changes in hepatocytes. In contrast, both gld and lpr mice had lower aminotransferase levels with milder histological changes. Reverse-transcription polymerase chain reaction and flow cytometric analysis showed that Fas ligand was induced in the liver shortly after the concanavalin A injection and was predominantly expressed on intrahepatic T cells. Administration of monoclonal antibody neutralizing mouse Fas ligand could reduce the aminotransferase increase.

CONCLUSIONS

The results indicate that Fas ligand plays a role in the T cell-dependent hepatitis induced by concanavalin A administration.

[Efficacy of interferon alpha in primary prevention of preneoplastic lesions in a transgenic murine model of hepatocellular carcinoma related to the interaction between woodchuck hepatitis viruses and c-myc oncogene]

OBJECTIVES

C-myc oncogene overexpression by near insertion of hepatitis B virus is important in woodchuck hepatocarcinogenesis. This DNA fragment was transferred in mice who developed hepatocellular carcinoma via preneoplastic lesions. In the present study, we tested the preventive effect of alpha interferon on the incidence of hepatocyte dysplasia.

METHODS

Human recombinant alpha interferon hybrid B/D was continuously administered at increasing doses (0 to 10,000 IU/g) in a transgenic mouse model. One cohort was treated from day 21 to day 80. A histological liver examination was performed and the transgene expression was assessed by hybridization with or without previous genic amplification, and by indirect immunofluorescence.

RESULTS

At day 15, histological liver examination was normal. Interferon treatment decreased the expression of viral sequences, but not of c-myc. At day 80, interferon treatment resulted in a reduction of the incidence and severity of dysplasic lesions, and a marked decrease in c-myc overexpression.

CONCLUSION

In this transgenic mouse model, alpha interferon treatment decreased the incidence and severity of precancerous lesions, due to a reduction in c-myc overexpression. This prophylaxis could be of interest in human hepatocarcinogenesis where c-myc overexpression is frequent.