Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.6.1.2 (alanine aminotransferase)
 26,722 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Liver fibrosis is commonly observed in chronic liver disease. However, the immunological mechanisms underlying hepatic fibrosis due to chronic inflammation are not well defined, mainly because suitable experimental models have not been established. We have found that weekly i.v. administration of concanavalin A (Con A) in BALB/c mice brought about a striking alanine aminotransferase increase, resulting in piecemeal necrosis with bridging fibrosis in the parenchyma. Using this fibrosis model, we demonstrated the kinetics of cytokine mRNA expression in liver. Transforming growth factor (TGF)-beta1, TGF-alpha, basic fibroblast growth factor (bFGF) and hepatocyte growth factor mRNAs were up-regulated after each Con A administration. Furthermore, either anti-IFN-gamma, anti-tumor necrosis factor (TNF)-alpha or anti-TGF-beta mAb given together with Con A markedly inhibited the development of hepatic fibrosis. Treatment with either anti-IFN-gamma or anti-TNF-alpha mAb also completely prevented hepatic injury; in contrast, treatment with anti-TGF-beta mAb did not. The treatment with anti-TGF-beta mAb did not affect the levels of hepatic mRNAs for either IFN-gamma or TNF-alpha after Con A injection. Treatment with either anti-IFN-gamma or anti-TNF-alpha did not affect the expression levels of TGF-beta in the liver. In conclusion, the continuous presence of both severe liver damage and up-regulation of TGF-beta synthesis is necessary to induce hepatic fibrosis in this model.
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PMID:Immunopathogenesis of hepatic fibrosis in chronic liver injury induced by repeatedly administered concanavalin A. 1046 70

To clarify the involvement of growth and differentiation of liver macrophages mediated by macrophage colony-stimulating factor (M-CSF) in the liver injury induced by Propionibacterium acnes (P. acnes) and lipopolysaccharide (LPS), we used M-CSF-deficient osteopetrotic (op/op) mice. Seven days after injection of P. acnes, granulomas as well as the numbers of Thy-1.2-, Mac-1-, and ERMP-20-positive cells and F4/80-positive areas in the liver were significantly reduced in the op/op mice compared to the normal littermates. After injection of LPS, serum levels of alanine aminotransferase as well as concentrations of IL-1beta and TNF-alpha in the serum and liver were significantly lower in the op/op mice than in the normal littermates, whereas the concentrations of IL-1beta and TNF-alpha in the spleen were similar in op/op mice and normal littermates. These results suggest that M-CSF plays a partial but highly significant role in the development of liver injury induced by P. acnes and LPS via an intrahepatic increase of primed macrophages including those in granulomas, in response to P. acnes, which produce proinflammatory cytokines such as IL-1beta and TNF-alpha.
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PMID:Experimental liver injury induced by Propionibacterium acnes and lipopolysaccharide in macrophage colony stimulating factor-deficient osteopetrotic (op/op) mice. 1054 45

Although neutrophils have been implicated in the hepatic injury elicited by gut ischemia/reperfusion (I/R), the contribution of other leukocyte populations to this injury process remains unclear. The objective of this study was to determine whether lymphocytes contribute to gut I/R-induced microvascular dysfunction and inflammatory responses in the liver. Intravital videomicroscopy was used to monitor leukocyte recruitment, the number of nonperfused sinusoids and pyridine nucleotide (NADH) autofluorescence in livers of wild-type, SCID, and interferon-gamma (IFN-gamma) knockout mice exposed to 15 min of gut ischemia and 1 h of reperfusion. In wild-type mice, gut I/R elicited significant increases in the number of stationary leukocytes, nonperfused sinusoids, NADH autofluorescence (indicating hypoxia), and elevated plasma alanine aminotransferase (ALT) and TNF-alpha levels. All of these responses were profoundly attenuated in SCID mice, while only some of the responses (in the midzonal region) were blunted in IFN-gamma knockout mice. Reconstitution (24 h before ischemia) of the circulating lymphocyte pool with T-cell enriched splenocytes, but not T cell deficient (from nude mice), CD4+ T-cell depleted splenocytes or splenocytes derived from IFN-gamma knockout mice, allowed the SCID mice to respond to gut I/R in a manner similar to wild-type mice. Some of the responses were restored following reconstitution with CD8+ T-cell depleted splenocytes. These findings implicate CD4+ T-lymphocytes and IFN-gamma in the hepatic microvascular dysfunction and inflammatory cell accumulation elicited by gut I/R.
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PMID:T-lymphocytes contribute to hepatic leukostasis and hypoxic stress induced by gut ischemia-reperfusion. 1065 78

IL-13 has been shown to exert potent anti-inflammatory properties. In this study, we elucidated the functional role of endogenous IL-13 in a murine model of septic peritonitis induced by cecal ligation and puncture (CLP). Initial studies demonstrated that the level of IL-13 increased in tissues including liver, lung, and kidney, whereas no considerable increase was found in either peritoneal fluid or serum after CLP. Immunohistochemically, IL-13-positive cells were Kupffer cells in liver, alveolar macrophages in lung, and epithelial cells of urinary tubules in kidney. IL-13 blockade with anti-IL-13 Abs significantly decreased the survival rate of mice after CLP from 53% to 14% on day 7 compared with control. To determine the potential mechanisms whereby IL-13 exerted a protective role in this model, the effects of anti-IL-13 Abs on both local and systemic inflammation were investigated. Administration of anti-IL-13 Abs did not alter the leukocyte infiltration and bacterial load in the peritoneum after CLP but dramatically increased the neutrophil influx in tissues after CLP, an effect that was accompanied by significant increases in the serum levels of aspartate transaminase, alanine transaminase, blood urea nitrogen, and creatinine. Tissue injury caused by IL-13 blockade was associated with increases in mRNA and the protein levels of CXC chemokines macrophage inflammatory protein-2 and KC as well as the CC chemokine macrophage inflammatory protein-1alpha and the proinflammatory cytokine TNF-alpha. Collectively, these results suggest that endogenous IL-13 protected mice from CLP-induced lethality by modulating inflammatory responses via suppression of overzealous production of inflammatory cytokines/chemokines in tissues.
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PMID:Expression and contribution of endogenous IL-13 in an experimental model of sepsis. 1067 15

The hepatoprotective effect of ZNC-2381 (1-(4-aminophenyl) methyl-3-(3-nitrophenyl)-1,3-dihydroimidazo[4,5-b]pyridine-2-one), a novel 2-one dihydroimidazopyridine derivative, has been evaluated in several experimental models of hepatic injury. In mice, oral ZNC-2381, administered at doses of 3, 10 or 30 mgkg(-1), 1 h before induction of hepatic injury with concanavalin A, dose-dependently inhibited increases in serum alanine aminotransferase (ALT) activity. Apoptosis of liver cells, as indicated by DNA fragmentation (nucleosome assay) and DNA-ladder formation (electrophoresis), was also inhibited dose-dependently. ZNC-2381 dose-dependently inhibited concanavalin A-induced increases in serum tumour necrosis factor (TNF)-alpha levels, and TNF-alpha mRNA expression in the liver. Oral ZNC-2381 also dose-dependently inhibited increases in serum ALT activity in mice with hepatic injury induced by Propionibacterium acnes and a bacterial lipopolysaccharide (LPS) or D-galactosamine-LPS, and in rats with D-galactosamine-induced hepatic injury. These results indicate that oral ZNC-2381 inhibits cytokine (TNF-alpha) production and cytokine-related hepatocellular apoptosis, and might thus prevent different types of hepatic injury.
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PMID:Effects of ZNC-2381, a new oral compound, on several hepatic injury models and on hepatocellular apoptosis in mice and rats. 1086 41

The aim of the study was to investigate the effect of the immunosuppressant FK 506 (tacrolimus hydrate) on acute liver injury induced by Propionibacterium acnes and lipopolysaccharide (LPS). Acute liver injury was induced in male Wistar rats by injecting the animals with P. acnes (10 mg/rat), and administering LPS (10 microg/rat) seven days later. One group was given FK 506 (1 mg/kg) 24 and 2 hr before administration of LPS, and the other group was given the same dose of saline. The 24-hr survival rate, serum alanine aminotransferase (ALT) concentration, and tumor necrosis factor (TNF) -alpha mRNA and protein concentrations in the liver and spleen were then compared. Hepatic macrophages were also isolated from rats seven days after P. acnes injection, LPS, and FK 506 or saline were added to the culture supernatant, and TNF-alpha production was studied. The 24-hr survival rate was 100% in the FK 506-treated group, in contrast with 16.6% in the saline group. Four hours after LPS injection, the serum ALT concentration was 755 +/- 401 in the saline group versus 119 +/- 42 units/ml (P < 0.01) in the FK 506-treated group. The serum TNF-alpha concentration was lower in the FK 506-treated group (1,419 +/- 957 pg/ml) than in the saline group (9205 +/- 2215) (P < 0.01). The mRNA and protein concentrations in the liver and spleen in the two groups did not differ significantly 1 hr after LPS injection but were significantly lower in the FK 506-treated group after 4 hr. FK 506 did not directly inhibit TNF-alpha production by isolated cultured hepatic macrophages. FK 506 is unable to inhibit initial TNF-alpha production by hepatic macrophages (or probably that by splenic macrophages either) stimulated by injection of LPS in P. acnes + LPS-induced acute liver injury. However, the immunosuppressant does limit hepatic damage by inhibiting subsequent aggravation of inflammation by the cytokine network.
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PMID:Preventive effect of FK 506 (tacrolimus hydrate) on experimentally induced acute liver injury in rats. 1111 73

Immunity to allogeneic MHC Ags is weak in rodent livers, raising questions as to the mechanisms that might control responses in this organ. Infection with an adenovirus vector reveals that T cell-mediated immunity to nonself-Ags in the liver is self-limiting. Virus-induced liver injury decreases and coincides with disappearance of virus-specific CTL, concomitant to an increase of apoptotic T cells early after infection. But whereas death in CD4 cells is independent of Fas, perforin, and TNF-alpha, that of CD8 cells requires Fas and not perforin or TNF-alpha pathways. Fas ligand is expressed on liver-infiltrating cells, pointing to death by fratricide that causes almost complete disappearance of virus-specific CTL 4 wk after infection. CTL elimination is virus dose dependent, and high doses induced high alanine aminotransferase values, elevated expression of Fas ligand on CD8 cells, and increased CD8 cell migration into the infected liver.
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PMID:Fas-mediated apoptosis causes elimination of virus-specific cytotoxic T cells in the virus-infected liver. 1120 53

To clarify the relationship between coffee and fitness, we investigated the effect of coffee on weight gain and total cholesterol as well as production of cytokines and activities of GOT (aspartate aminotransferase; EC 2.6.1.1.) and GPT (alanine aminotransferase; EC 2.6.1.2.) as injected lipopolysaccharides. Forty-eight male Wistar rats were divided into three dietary groups (n=16), which were fed a stock diet (control group), the diet supplemented with freeze-dried coffee of 6.2 g/kg (0.62% coffee group), and the diet supplemented with freeze-dried coffee of 13.6 g/kg (1.36% coffee group). It was confirmed by HPLC analysis that the serum caffeine concentrations in both coffee groups became significantly higher in 140 days after the start of feeding. No significant differences in body weight and serum cholesterol were found between the coffee groups and control group, though the coffee groups tended to be somewhat high at cholesterol level. Activities of serum GOT and GPT increased at 2 h after LPS injection, but in the coffee groups were significantly suppressed (p<0.05). However, the coffee feeding could not suppress the increases of serum cytokine (TNF-alpha and IL-6) levels. These results suggest that coffee may serve as a preventive against liver injury.
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PMID:Coffee and fitness-coffee suppresses lipopolysaccharide-induced liver injury in rats. 1122 4

Activation of Kupffer cells by gut-derived endotoxin is associated with alcohol-induced liver injury. Recently, it was shown that CD14-deficient mice are more resistant to endotoxin-induced shock than wild-type controls. Therefore, this study was designed to investigate the role of CD14 receptors in early alcohol-induced liver injury using CD14 knockout and wild-type BALB/c mice in a model of enteral ethanol delivery. Animals were given a high-fat liquid diet continuously with ethanol or isocaloric maltose-dextrin as control for 4 wk. The liver to body weight ratio in wild-type mice (5.8 +/- 0.3%) was increased significantly by ethanol (7.3 +/- 0.2%) but was not altered by ethanol in CD14-deficient mice. Ethanol elevated serum alanine aminotransferase levels nearly 3-fold in wild-type mice, but not in CD14-deficient mice. Wild-type and knockout mice given the control high-fat diet had normal liver histology, whereas ethanol caused severe liver injury (steatosis, inflammation, and necrosis; pathology score = 3.8 +/- 0.4). In contrast, CD14-deficient mice given ethanol showed minimal hepatic changes (score = 1.6 +/- 0.3, p < 0.05). Additionally, NF-kappa B, TGF-beta, and TNF-alpha were increased significantly in wild-type mice fed ethanol but not in the CD14 knockout. Thus, chronic ethanol feeding caused more severe liver injury in wild-type than CD14 knockouts, supporting the hypothesis that endotoxin acting via CD14 plays a major role in the development of early alcohol-induced liver injury.
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PMID:Reduced early alcohol-induced liver injury in CD14-deficient mice. 1125 35

The functions of leukocyte-derived chemotaxin 2 (LECT2), a novel liver-specific protein, are not well defined, especially after hepatic injury. The changes in expression of LECT2 mRNA were investigated after concanavalin A (Con A)-induced hepatic injury in mice. Serum glutamate pyruvate transaminase (s-GPT) activity and the percentage of liver DNA fragmentation, an indicator of hepatic apoptosis, increased 8 h after intravenous administration of Con A (13 mg/kg). Expression of LECT2 mRNA was reduced from 8-24 h after injection of Con A, but was detected again 48 h after recovery from hepatic injury. Expression of tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma mRNA was observed in liver 2 h after Con A injection. Z-Val-Ala-Asp(OMe)-CH2F (Z-VAD-FMK), a caspase inhibitor, was administered to mice to investigate whether LECT2 was involved in apoptosis of liver cells after Con A injection. Z-VAD-FMK inhibited s-GPT activity and DNA fragmentation in the liver 8 h after Con A-induced hepatic injury, but did not prevent the reduction of LECT2 mRNA, or induction of TNF-alpha and IFN-gamma mRNA expression. When the relation between expression of LECT2, TNF-alpha and IFN-gamma mRNAs was examined 8 h after Con A injection in wild-type or immunodeficient (nu-/nu-) mice, the increase in TNF-alpha and IFN-gamma mRNA expression was found to be closely related to a reduction in LECT2 mRNA expression. These results suggest that the reduction in expression of LECT2 mRNA is not directly involved in apoptosis and may be inversely related to the expression of TNF-alpha and/or IFN-gamma mRNA in the injured liver.
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PMID:Possible changes in expression of chemotaxin LECT2 mRNA in mouse liver after concanavalin A-induced hepatic injury. 1130 8


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