Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019158 (hepatitis)
 30,205 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ethanol toxicity on liver is a function of duration of alcoholism, amount of daily intake of alcohol and patient's nutrition. The threshold of alcohol toxicity on the liver is about 40 g of ethanol daily in men and 20-30 g in women, however liver cirrhosis develops in no more than 8-20% of patients exceeding this values. Ethanol is oxidized in the liver to acetaldehyde--a compound considerably more toxic than ethanol itself. Despite small amount of alcohol dehydrogenase (ADH) found in gastric mucosa, the metabolism of ethanol in this site may have an important hepatoprotective effect. The oxidation of ethanol is associated with a change of hepatocyte redox homeostasis, which leads to a number of metabolic disorders such as lactic acidosis, hyperlipidaemia and hyperuricaemia. Chronic ethanol consumption does not influence ADH activity, but has a profound stimulatory effect on microsomal enzymes, in particular cytochrome CYP2E1. This fact is responsible for development in alcoholic liver associated with rise of oxygen consumption, excessive production of free radicals and increased metabolism of ethanol, vitamin A and testosterone. Ethanol and acetaldehyde have a deleterious effect, both the direct and indirect, on hepatocytes e.g., generating radical oxygen species and damaging intestinal mucosal barrier. Cellular oxidative stress that is caused by both an excess of free radicals and the antioxidatives' deficiency (glutathion, vitamin E, phosphatidylcholine), may be the principal factor responsible for progression of alcoholic liver disease. Among other factors accelerating alcohol-related liver lesion there are certain drugs, high fat diet, infection with HCV and genetic factors (female sex, enzymatic polymorphic forms of ADH and ALDH, hemochromatosis). Great importance in pathogenesis of necrotic and inflammatory hepatic events is being attributed to portal endotoxaemia and cytokines induced within the liver, in particular TNF-alpha and interleukin 8. These cytokines play a key role in development of alcoholic hepatitis, which clinical severity ranges from subclinical to fatal forms. Apart from abstinence, the treatment of alcohol liver disease is based on hyperalimentation, since alcoholism is generally associated with protein malnutrition. In severe forms of alcohol hepatitis corticosteroids are recommended.
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PMID:[Alcoholic liver disease]. 1290 Dec 71

Effects of adenoviral infection on in vivo responses to LPS mediated by TNF-alpha were evaluated in a murine model. Adenovirus-infected mice showed decreased mortality from fulminant hepatitis induced by administration of LPS or staphylococcal enterotoxin B in the presence of D-galactosamine. Importantly, TNF-alpha resistance genes within adenoviral E3 region were not required, because E1,E3-deleted vectors showed similar effects. Adenovirus-infected mice exhibited higher TNF-alpha levels after LPS stimulation, no difference in TNFR1 expression, and similar mortality from Fas-induced fulminant hepatitis. Decreased production of IL-6 and KC in response to exogenous TNF-alpha, in addition to protection from TNF-alpha, suggested that adenoviral infection results in TNF-alpha tolerance.
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PMID:Adenoviral infection decreases mortality from lipopolysaccharide-induced liver failure via induction of TNF-alpha tolerance. 1292 93

T cell-mediated immune responses are implicated in the pathogenesis of a variety of liver disorders; however, the underlying mechanism remains obscure. Con A injection is a widely accepted mouse model to study T cell-mediated liver injury, in which STAT6 is rapidly activated. Disruption of the IL-4 and STAT6 gene by way of genetic knockout abolishes Con A-mediated liver injury without affecting IFN-gamma/STAT1, IL-6/STAT3, or TNF-alpha/NF-kappaB signaling or affecting NKT cell activation. Infiltration of neutrophils and eosinophils in Con A-induced hepatitis is markedly suppressed in IL-4 (-/-) and STAT6(-/-) mice compared with wild-type mice. IL-4 treatment induces expression of eotaxins in hepatocytes and sinusoidal endothelial cells isolated from wild-type mice but not from STAT6(-/-) mice. Con A injection induces expression of eotaxins in the liver and elevates serum levels of IL-5 and eotaxins; such induction is markedly attenuated in IL-4(-/-) and STAT6(-/-) mice. Finally, eotaxin blockade attenuates Con A-induced liver injury and leukocyte infiltration. Taken together, these findings suggest that IL-4/STAT6 plays a critical role in Con A-induced hepatitis, via enhancing expression of eotaxins in hepatocytes and sinusoidal endothelial cells, and induces IL-5 expression, thereby facilitating recruitment of eosinophils and neutrophils into the liver and resulting in hepatitis.
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PMID:Crucial role of IL-4/STAT6 in T cell-mediated hepatitis: up-regulating eotaxins and IL-5 and recruiting leukocytes. 1296 Mar 53

A 21-year-old man was admitted to our hospital for acute hepatitis of unknown cause. His liver function improved with rest, but worsened 2 months later. He developed a high fever and pancytopenia. The serum level of cytokines including TNF-alpha, IFN-gamma, IL-6, and M-CSF was elevated, and hemophagocytes were seen in bone marrow. These findings suggested a hemophagocytic syndrome-like state. With prednisolone, gamma-globulin, and G-CSF, the high fever disappeared and the patient's liver function gradually recovered. However, the severe pancytopenia persisted. The bone marrow became acellular with a small number of hemophagocytes, and hepatitis-associated aplastic anemia was diagnosed. After immunosuppressive therapy with ATG, CyA and G-CSF was started, and the patient showed hematopoietic reconstitution. The bone marrow CD4+/CD8+ lymphocyte ratio recovered to within the normal range, and the serum cytokines including TNF-alpha and IFN-gamma decreased. The increase in serum cytokines, particularly TNF-alpha and INF-gamma, as well as the presence of activated T cells associated with the preceding hemophagocytic syndrome-like state may have predisposed this patient to aplastic anemia.
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PMID:[Hepatitis-associated aplastic anemia preceded by a hemophagocytic syndrome-like state]. 1463 47

Nrf2 is a basic leucine zipper transcriptional activator that is essential for the coordinate transcriptional induction of various antioxidant drug-metabolizing enzymes. Numerous studies have firmly established Nrf2's importance in protection from oxidative stress and certain chemical insults. Given the protective function of Nrf2, surprisingly few studies have focused on the relationship between Nrf2 and apoptosis. Therefore, we analysed how Nrf2 influences Fas signaling using Nrf2-deficient T cells. At a concentration of 1 microg/ml, the anti-Fas antibody induced 60% of cell death in Nrf2-deficient cultured thymocytes while, using the same treatment, only 40% of Nrf2 wild-type thymocytes died (P<0.05). Nrf2 deficiency enhances the sensitivity of Fas-mediated apoptosis in T cells. Next we examined the effect of Nrf2 deficiency during hepatocellular apoptosis in vivo. In comparison to wild-type mice, Nrf2-deficient mice displayed more severe hepatitis after induction with the anti-Fas antibody or tumor necrosis factor (TNF)-alpha. The enhanced sensitivity to anti-Fas or TNF-alpha stimulation was restored by preadministration of glutathione ethyl monoester, a compound capable of passing the cell membrane and upregulating the intracellular levels of glutathione. The results indicated that Nrf2 activity regulates the sensitivity of death signals by means of intracellular glutathione levels.
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PMID:Nrf2 regulates the sensitivity of death receptor signals by affecting intracellular glutathione levels. 1468 86

Hepatitis C virus (HCV) is one of the principal causes of hepatitis, which in more than 80% of cases leads to chronic lesions in the liver and involvement of extrahepatic organs. It remains unknown why the infection so frequently turns chronic, independently of patient age. Using immunocytochemistry (IHC) and in situ hybridization (ISH) (both linked to the ImmunoMax technique) we examined cell sources of TNF-alpha, IL-1alpha, and IL-2 in control and HCV-infected children and adults. We demonstrated augmented expression of all the cytokines in HCV-infected patients compared to controls. No differences were detected in amounts of studied transcripts or cytokine proteins between biopsies taken from HCV-infected children and adults. Expression of TNF-alpha was localized mainly in liver sinusoidal cells (macrophages, endothelial cells). A high proportion of hepatocytes demonstrated expression of TNF-alpha, IL-1alpha, and IL-2. In both groups of patients, higher amounts of cytokine proteins than studied transcripts were demonstrated. The augmented expression of TNF-alpha, IL-1alpha, and IL-2 in liver with a similar proportion of involved cells (mainly hepatocytes) in children and in adults points to participation of the cytokines in the pathogenesis of chronic hepatitis C. The expression is insufficient to terminate the infection and may be linked with the comparably frequent chronic transformation of HCV infection noted in children and adults.
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PMID:Expression of cytokines (TNF-alpha, IL-1alpha, and IL-2) in chronic hepatitis C: comparative hybridocytochemical and immunocytochemical study in children and adult patients. 1468 15

Administration of Con A induces liver injury that is considered to be an experimental model for human autoimmune or viral hepatitis, where immunopathology plays roles mediated by activated lymphocytes, especially NK1.1+ CD3+ NKT cells, and inflammatory cytokines, including IFN-gamma and IL-4. In the present study we investigated the role of WSX-1, a component of IL-27R, in Con A-induced hepatitis by taking advantage of WSX-1 knockout mice. WSX-1-deficient mice were more susceptible to Con A treatment than wild-type mice, showing serum alanine aminotransferase elevation and massive necrosis in the liver. Although the development of NKT cells appeared normal in WSX-1 knockout mice, purified NKT cells from the knockout mice produced more IFN-gamma and IL-4 than those from wild-type mice in response to stimulation with Con A both in vitro and in vivo. In addition, hyperproduction of proinflammatory cytokines, including IL-1, IL-6, and TNF-alpha, was observed in the knockout mice after Con A administration. These data revealed a novel role for WSX-1 as an inhibitory regulator of cytokine production and inflammation in Con A-induced hepatitis.
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PMID:Hyperproduction of proinflammatory cytokines by WSX-1-deficient NKT cells in concanavalin A-induced hepatitis. 1500 60

S-adenosyl-L-methionine (SAM) is synthesized by methionine adenosyltransferases (MATs). Ablation of the liver-specific MAT1A gene results in liver neoplasia and sensitivity to oxidant injury. Here we show that acidic sphingomyelinase (ASMase) mediates the downregulation of MAT1A by TNF-alpha. The levels of MAT1A mRNA as well as MAT I/III protein decreased in cultured rat hepatocytes by in situ generation of ceramide from exogenous human placenta ASMase. Hepatocytes lacking the ASMase gene (ASMase-/-) were insensitive to TNF-alpha but were responsive to exogenous ASMase-induced downregulation of MAT1A. In an in vivo model of lethal hepatitis by TNF-alpha, depletion of SAM preceded activation of caspases 8 and 3, massive liver damage, and death of the mice. In contrast, minimal hepatic SAM depletion, caspase activation, and liver damage were seen in ASMase-/- mice. Moreover, therapeutic treatment with SAM abrogated caspase activation and liver injury, thus rescuing ASMase+/+ mice from TNF-alpha-induced lethality. Thus, we have demonstrated a new role for ASMase in TNF-alpha-induced liver failure through downregulation of MAT1A, and maintenance of SAM may be useful in the treatment of acute and chronic liver diseases.
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PMID:Acidic sphingomyelinase downregulates the liver-specific methionine adenosyltransferase 1A, contributing to tumor necrosis factor-induced lethal hepatitis. 1506 22

Artemisia capillaris Thunb. has been used for the remedy of liver diseases such as hepatitis, jaundice and fatty liver in traditional oriental medicine. However, despite extensive pharmacological studies, the molecular mechanism of the anti-inflammatory effect of Artemisia capillaris Thunb. has hardly been studied. In the present study, we investigated the pharmacological action mechanism on LPS-induced liver inflammation in HepG2 human hepatocarcinoma cells and rat liver. Aqueous extract from Artemisia capillaris Thunb. (AEAC) inhibits expression of inflammatory proteins including iNOS, COX-2 and TNF-alpha. Also, nuclear translocation of NF-kappaB and degradation of I-kappaBalpha are blocked by AEAC pretreatment. These results suggest that the inhibitory effect of AEAC on the expression of inflammatory proteins involves suppression of NF-kappaB activation.
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PMID:The aqueous extract from Artemisia capillaris Thunb. inhibits lipopolysaccharide-induced inflammatory response through preventing NF-kappaB activation in human hepatoma cell line and rat liver. 1506 76

The aim of this study was to evaluate the effect of astilbin on concanavalin A (Con A)-induced hepatitis, a T cell-dependent model of liver injury. Con A administration resulted in a severe liver injury in mice, with a strong increment in spleen cell adhesion and liver infiltration of T cells, as well as in tumour necrosis factor (TNF)-alpha production. Against this liver injury, astilbin significantly inhibited the elevation in transaminase activity, reduced the TNF-alpha production, and improved the histological changes, including inflammatory infiltration, hepatocyte necrosis and degeneration and Kupffer cell hyperplasia. In addition, astilbin inhibited the adhesion of spleen cells and purified T lymphocytes isolated from the liver-injured mice to fibronectin, laminin and type IV collagen.Moreover, the adhesion of human Jurkat T cells to endothelial cell line ECV-304 was also inhibited by astilbin. These results suggest that the improvement of the T cell-mediated liver injury by astilbinmay be related to the reduction in TNF-alpha production and in T cell adhesion to extracellular matrices and endothelial cells.
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PMID:Astilbin prevents concanavalin A-induced liver injury by reducing TNF-alpha production and T lymphocytes adhesion. 1510 95


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