UMLS:C0239946 - FACTA Search

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Query: UMLS:C0239946 (liver fibrosis)
8,268 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The liver is the largest organ in the body providing a large number of essential functions for the organism. It is the center for the metabolism of nutrients and drugs, and plays a key role in the unspecific immune system by harbouring Kupfer cells, the majority of all macrophages. The liver is the main site for the synthesis of many different metabolites and releases most of the plasma proteins. All these functions of the liver must be coordinated and regulated in response to metabolic changes and minor or major injuries. This is accomplished by metabolites, the autonomous nerve system, the endocrine system and by cytokines, which form a complex network of mediator molecules. Cytokines modulate liver metabolism in many ways. Synthesis of acute phase proteins is regulated by cytokines such as IL-1, IL-6, IL-11, leukemia inhibitory factor, TNF, transforming growth factor beta, epidermal growth factor, and ciliary derived neurotropic factor, which interact synergistically with corticosteroids and insulin. Hepatic lipid metabolism and hepatic carbohydrate metabolism are also regulated by cytokines and by classical hormones. Cytokines play an important role in the pathogenesis of liver diseases and liver fibrosis, which is the common morphological reaction after chronic injury of the liver. An uncontrolled production of extracellular matrix and its impaired degradation destroy the architecture of the liver and its function. Fat-storing cells (Ito cells, lipocytes, perisinusoidal cells) are the major source of extracellular matrix in the liver. They are activated to proliferate or to produce extracellular matrix compounds by cytokines like transforming growth factor beta, and platelet derived growth factor (PDGF). Interferon gamma and alpha inhibit this activation. Modulation of fibrogenesis by these cytokines may be helpful for future treatment of liver fibrosis.
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PMID:Cytokines and the liver in health and disease. Effects on liver metabolism and fibrogenesis. 752 63

Cytokines constitute a complex network of molecules involved in the regulation of the inflammatory response and the homeostasis of organ functions. Cytokines coordinate physiologic and pathologic processes going on in the liver, such as liver growth and regeneration, inflammatory processes including viral liver disease, liver fibrosis and cirrhosis. Liver growth and regeneration are regulated by several cytokines. The platelet-derived hepatocyte growth factor, in particular, delivers a strong mitogenic stimulus for hepatocyte regeneration. The cell-mediated immune response plays a central role in hepatocellular necrosis and in the immunopathogenetic mechanisms involved in viral clearance and persistence in liver disease of viral etiology. In this context, cytokines modulate the immune system and exert direct antiviral activity by cytopathic and non-cytopathic mechanisms, as demonstrated in a transgenic mouse model. IL-6, TNF-alpha, IL-1 and IL-2 increase in acute fulminant viral hepatitis; in fact, they have pro-inflammatory and cytotoxic effects. Reduced IL-2 and IFN-alpha synthesis and increased serum levels of IL-1 and IL-2 soluble receptor (IL-2R) have been observed in HBV chronic liver disease. In HCV chronic hepatitis, IL-2R increases as well, while IFN-gamma and IL-2 decrease. In personal experimental observations, intra-hepatic messenger RNA expression of several cytokines was measured in liver specimens of patients with chronic HBV and HCV infections: patients with HCV chronic liver disease had higher levels of IL-2, IL-6, IL-10, and IFN-gamma. These data are in accordance with immunological studies showing a vigorous cell-mediated immune response in HCV chronic liver disease and a deficient immune response in HBV chronic hepatitis.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Cytokine mediators in acute inflammation and chronic course of viral hepatitis]. 772 1

Degradation of extracellular matrix proteins is performed by metalloproteinases which are inhibited by tissue inhibitors of metalloproteinases (TIMP). We expressed the murine TIMP-1 protein in E. coli and prepared a polyclonal antiserum against the recombinant protein. Using this antiserum we studied the biosynthesis and glycosylation of murine TIMP-1 protein in COS-7 cells transfected with a TIMP-1 expression plasmid by metabolic labeling and indirect immunofluorescence studies. In primary rat hepatocytes we show for the first time that TIMP-1 protein expression is up-regulated upon stimulation with IL-1 beta and IL-6. Since TIMP-1 is induced during the acute phase reaction it could possibly be involved in the pathogenesis of liver fibrosis.
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PMID:TIMP-1 protein expression is stimulated by IL-1 beta and IL-6 in primary rat hepatocytes. 804

An increasing body of experimental evidence is emerging to incriminate oxidative stress as a pivotal signal for liver fibrogenesis. This paper reviews the results from our studies testing this hypothesis. In the rat model of alcoholic liver disease, the importance of oxidative stress was supported by marked accentuation of liver fibrosis by dietary supplementation of iron, a pro-oxidant, and the significant correlation of the liver malondialdehyde (MDA) and 4-hydroxynonenal (4HNE) levels with the hepatic collagen accumulation. Both MDA and 4HNE adduct epitopes were detected intensely and diffusely in close association with collagen deposition. The direct cause and effect relationship between MDA/4HNE and Ito cell stimulation was indicated by the demonstration of Ito cell collagen gene induction by these aldehydes in culture. In primary cultures of rat Kupffer cells (KC), addition of antioxidants such as alpha-tocopherol acetate and succinate suppressed mRNA expression and the release of interleukin (IL)-6 and tumour necrosis factor alpha (TNF alpha). In rats with biliary fibrosis, an increase in the liver MDA level was accompanied by enhanced mRNA expression of procollagen alpha 1(I) and transforming growth factor beta 1 in Ito cells; and that of TNF alpha and IL-6 in KC. Furthermore, the gel shift assay of KC nuclear extracts showed enhanced NF-kB DNA binding activity. These results support the proposal that enhanced oxidative stress constitutes an important signal for activation of Kupffer and Ito cells in experimental liver fibrogenesis.
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PMID:Roles of oxidative stress in activation of Kupffer and Ito cells in liver fibrogenesis. 858 43

The role of the anti-inflammatory cytokine interleukin-10 (IL-10) was investigated in the mouse model of liver injury induced by carbon tetrachloride (CCl4). To address the role of endogenous IL-10 production, acute hepatitis was induced by CCl4 in C57Bl/6 IL-10 gene knock out (KO) and wild-type (WT) mice. After CCl4 challenge, serum and liver levels of tumor necrosis factor-alpha (TNF-) and serum levels of transforming growth factor-beta 1 (TGF-beta1) increased and were significantly higher in IL-10 KO mice, whereas IL-6 serum levels were only slightly increased compared with WT mice. At histological examination, the livers disclosed a significantly more prominent neutrophilic infiltration in IL-10 KO mice 12 and 24 hours after CCl4 injection. In contrast, hepatocyte necrosis, evaluated by histological examination and serum alanine aminotransferase levels, was only marginally affected. The proliferative response of hepatocytes, assessed by the proliferating cell nuclear-antigen labeling index, was significantly increased in IL-10 KO mice, compared with WT mice 48 hours after CCl4 injection. Finally, repeated CCl4 injections led to more liver fibrosis in IL-10 KO mice after 7 weeks. In conclusion, endogenous IL-10 marginally affects the hepatocyte necrosis although it controls the acute inflammatory burst induced by CCl4. During liver repair, it limits the proliferative response of hepatocytes and the development of fibrosis.
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PMID:Interleukin-10 controls neutrophilic infiltration, hepatocyte proliferation, and liver fibrosis induced by carbon tetrachloride in mice. 982 39

Cyclooxygenase 2 (COX-2) has been thought to be associated with liver fibrosis whereas it is well known that hepatic stellate cells (HSC) play a central role in the pathogenesis of liver fibrosis. There is little evidence of how COX-2 regulates the activation of human HSC or the mechanism involved. In this study, we investigated the effect of a COX-2 inhibitor, NS-398, on a line of human HSC, LI90. Our findings demonstrated that alpha-smooth muscle actin (alpha-SMA) protein expression was inhibited in a dose-dependent manner by treatment with NS-398. Proliferation cell nuclear antigen (PCNA) expression and cell growth were partially down-regulated. The generation of PGE2, IL-8, IL-6, and hyaluronan in the cultured medium was also inhibited. In conclusion, our findings imply that a selective COX-2 inhibitor might be a potential drug for the chemoprevention and treatment of liver fibrosis by inhibiting the activation of HSC.
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PMID:Inhibition of the expression of alpha-smooth muscle actin in human hepatic stellate cell line, LI90, by a selective cyclooxygenase 2 inhibitor, NS-398. 1237 3

The origin of myofibroblasts and the factors promoting their differentiation during liver fibrogenesis remain uncertain. During biliary-type fibrogenesis, the proliferation and chemoattraction of hepatic stellate cells (HSC) toward bile ducts is mediated by platelet-derived growth factor (PDGF), while myofibroblastic conversion of peribiliary cells distinct from HSC also occurs. We herein examined the phenotype of these peribiliary myofibroblasts as compared with myofibroblastic HSC and tested whether their differentiation was affected by PDGF. Biliary-type liver fibrogenesis was induced by common bile duct ligation in rats. After 48 hours, periductular fibrosis in portal tracts colocalized with smooth muscle alpha-actin-immunoreactive myofibroblasts, the majority of which were desmin negative. Simultaneously, in sinusoids, desmin immunoreactivity was induced in a large number of HSC, which were smooth muscle alpha-actin negative. Cultures of peribiliary myofibroblasts were expanded from isolated bile duct segments and compared with myofibroblastic HSC. Peribiliary myofibroblasts outgrowing from bile duct segments expressed smooth muscle alpha-actin, alpha1 (I) collagen mRNA, and PDGF receptor-beta subunit. Desmin immunoreactivity gradually decreased in cultured peribiliary myofibroblasts, contrasting with constant labeling of all myofibroblastic HSC. In addition, IL-6 expression in peribiliary myofibroblasts was up to 100-fold lower than in myofibroblastic HSC, whereas the expression of the complement-activating protease P100 in both cell types showed little difference and that of the extracellular matrix component fibulin 2 was similar. The expression of smooth muscle alpha-actin protein in cultured peribiliary myofibroblasts was stimulated by PDGF-BB and inhibited by STI571, a PDGF receptor tyrosine kinase inhibitor, whereas in bile duct-ligated rats, the administration of STI571 caused a significant decrease in peribiliary smooth muscle alpha-actin immunoreactivity, and to a lesser extent, a decrease in peribiliary fibrosis. These results indicate that peribiliary cells distinct from HSC undergo a PDGF-mediated conversion into myofibroblasts expressing IL-6 at lower levels than myofibroblastic HSC and contribute to the initial formation of biliary-type liver fibrosis.
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PMID:The myofibroblastic conversion of peribiliary fibrogenic cells distinct from hepatic stellate cells is stimulated by platelet-derived growth factor during liver fibrogenesis. 1259 32

In this study we investigated TNF-alpha and leptin levels in two different liver fibrosis models induced by carbon tetrachloride (CCl(4)) and common bile duct ligation (CBDL). A total of 36 male rats of Albino-Wistar strain were allocated to three groups. One of the groups was the control. The second group received 0.15 ml 100 g(-1) CCl(4) subcutaneously for 6 weeks, 3 days per week. The third group underwent common bile duct ligation (CBDL) and was monitored for 4 weeks. Histopathological investigation included fibrosis, steatosis and inflammation. Serum IL-6 and TNF-alpha levels were analysed by ELISA methods and leptin was analysed by RIA. Fibrosis and steatosis increased significantly in the CCl(4) group in comparison with the CBDL group (p < 0.01; p < 0.001). Leptin and TNF-alpha levels in CCl(4) group were higher than those in the CBDL and control groups (p < 0.05). TNF-alpha and leptin levels were not related to each another in either the CCl(4) group or the CBDL group (r=0.22, p > 0.05; r=0.19, p > 0.05). The IL-6 level was higher in the CCl(4) group in relation to severity of inflammation (p < 0.05). TNF-alpha and leptin levels were higher in animals with liver fibrosis induced by CCl(4), than they were in those whose liver fibrosis was induced by common bile duct ligation. Leptin and TNF-alpha may be less effective on the development of liver fibrosis in the group which underwent common bile duct ligation.
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PMID:TNF-alpha and leptin in experimental liver fibrosis models induced by carbon tetrachloride and by common bile duct ligation. 1538 44

Liver fibrosis is an over-accumulation of extra-cellular matrix (ECM) and the hepatic stellate cell (Ito cell) play a central role in the pathogenesis of liver fibrosis. There are a lot of growth factors and cytokines involved in the activation of hepatic stellate cell, including of transforming growth factor (TGF-alpha, TGF-beta1), platelet-derived growth factor (PDGF), interleukin (IL-1alpha,beta, IL-6) and tumor necrosis factor (TNF-alpha). Sho-saiko-to (TJ-9; Xiao-Chai-Hu-Tang in Chinese) was the most popular herbal medicine for the treatment of chronic liver disease in Chinese and Japanese. Our aim of the current study was to examine whether TJ-9 regulated the growth factors and cytokines in the fibrogenesis of bile duct ligated model. Therefore, we assessed the TJ-9's potential in regulating TGF-beta1, PDGF mRNA expression, the amount of IL-1alpha, IL-1beta, IL-6, TNF-alpha and the fibrotic marker "PIII NP" in the serum. Then, using the immunohistochemical stain to observe the TGF-beta1 expression in the tissue. Our results showed that TJ-9 at a dose of 0.5 g/(kgday) significantly reduced the serum level of PIII NP, the mRNA expression of TGF-beta1 and PDGF. For the cytokines involved in the activation of Ito cell, TJ-9 at a dose of 0.5 g/(kgday) significantly suppressed the increasing tendency of IL-1beta and enhanced the production of TNF-alpha. Finally, we concluded that: (1) TJ-9 at a dose of 0.5g/(kgday) significantly reduced the serum fibrotic marker PIII NP in the bile duct ligated model, and its mechanism was partly by means of downregulating the mRNA of TGF-beta1 and PDGF. These results also confirmed by the immunohistochemical staining of TGF-beta1. (2) TJ-9 at a dose of 0.5 g/(kgday) suppressed the increasing tendency of IL-1beta and stimulated the production of TNF-alpha to inhibit Ito cell proliferation and collagen formation.
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PMID:The role of TGF-beta 1 and cytokines in the modulation of liver fibrosis by Sho-saiko-to in rat's bile duct ligated model. 1565 68

Oxidative stress, in particular lipid peroxidation, induces collagen synthesis and causes fibrosis. The aim of this study was to assess the antioxidant and antifibrotic effects of erdosteine on liver fibrosis induced by biliary obstruction in rats. Liver fibrosis was induced in Wistar albino rats by bile duct ligation (BDL). Erdosteine (10 mg/kg, orally) or saline was administered for 28 days. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) levels were determined to assess liver functions and tissue damage, respectively. Pro-inflammatory cytokines, TNF-alpha, IL-1beta and IL-6 and antioxidant capacity (AOC) were assayed in plasma samples. Liver tissues were taken for determination of malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity and collagen content. Production of reactive oxidants was monitored by chemiluminescence assay. Serum AST, ALT, LDH, and plasma cytokines were elevated in the BDL group as compared to controls and were significantly decreased by erdosteine treatment. Hepatic GSH level and plasma AOC, depressed by BDL, were elevated back to control level with erdosteine treatment. Furthermore, hepatic luminol and lucigenin chemiluminescence (CL), MDA level, MPO activity and collagen content in BDL group increased dramatically compared to control and reduced by erdosteine treatment. Since erdosteine administration alleviated the BDL-induced oxidative injury of the liver and improved the hepatic functions, it seems likely that erdosteine with its antioxidant and antifibrotic properties, may be of potential therapeutic value in protecting the liver fibrosis and oxidative injury due to biliary obstruction.
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PMID:Erdosteine treatment attenuates oxidative stress and fibrosis in experimental biliary obstruction. 1721 33

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