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

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 model of liver cirrhosis was induced by CCl4 and alcohol in rats, which were subjected to splenectomy or given Tuftsin. The isolated and purified liver parenchymal, Kupffer and Ito cells were cultured with CCl4 and splenic conditional fluid or Tuftsin. The RNA isolated from the liver tissues of cirrhosis animals were hybridized with five kinds of cDNA probes. In this study we explored the mechanism of spleen's promoting effects on the liver cirrhosis formation at the whole body, cellular and molecular levels. The result showed that in cirrhosis model, the levels of IL1, IL6 and TNF alpha in serum of rats in imitative splenectomy or Tuftsin group were significantly increased compared to those in splenectomy group (P < 0.05). Cell culture showed that if medium contained CCl4 and splenic conditional fluid or Tuftsin, its cells can secrete more fibronectin, laminin and collagen I than those cultured in medium only contained CCl4 (P < 0.05). Slot blot hybridization showed that the RNA isolated from liver of rats in imitative splenectomy or Tuftsin group hybridized with probes of TNF alpha, IL1 beta, TGF beta and Collagen I had a more high density picture of X-ray than that isolated from liver of rats in the splenectomy group. Should be it a complex process for spleen to promote liver cirrhosis formation, in which the TGF beta gene expression enhancement may be the key of splenic effects on liver fibrosis.
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PMID:[The mechanism for splenic promoting effects on liver cirrhosis]. 869 73

Hepatic expression of the proinflammatory cytokine tumor necrosis factor-alpha (TNFalpha) occurs in many acute and chronic liver diseases, as well as following exposure to hepatotoxic chemicals, and is believed to help influence both the damage and repair processes that occur following these insults by regulating additional mediators. We examined the role of TNFalpha in transgenic mice deficient in TNF receptors (TNFR) utilizing carbon tetrachloride (CCl(4)) as a model hepatotoxic agent that allowed for the evaluation of necrosis, inflammation, and fibrosis. Hepatocyte damage, as evident by local areas of liver necrosis and elevated levels of serum transaminase, occurred to a similar degree in wild-type and TNFR-deficient knockout (KO) mice following acute exposure to CCl(4). In contrast, the inflammatory response, manifested as an inflammatory cell influx, as well as induction of chemokines and adhesion molecules that occurred in wild-type mice following treatment with CCl(4), was not as evident in TNFR-KO mice. This response was associated primarily with type-1 (TNFR1) rather than type-2 (TNFR2) receptor responses. Liver fibrosis resulting from chronic CCl(4) exposure was also markedly dependent upon TNFalpha as demonstrated by almost a complete histological absence of fibrosis in TNFR-deficient mice. This was further supported by marked reductions in procollagen and transforming growth factor beta synthesis in TNFR-deficient mice. Taken together, these results indicate that TNFalpha is responsible for regulating products that induce inflammation and fibrosis but not direct hepatocyte damage in CCl(4)-induced hepatotoxicity.
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PMID:The role of tumor necrosis factor-alpha in liver toxicity, inflammation, and fibrosis induced by carbon tetrachloride. 1174 Sep 10

INTRODUCTION:To intrestigate the relationship between tumor necrosis factor-alphaand liver fibrosis in patients with chronic liver disease.METHODS:Radioimmunoassay was made in 20 patients with mild chronic hepatitis(CMH),20 patients with severe chronic hepatitis(CSH),51 patients with liver cirrhosis(LC)and 32-normal persons to determine the contents of tumor necrosis factor-alpha(TNF-alpha),laminin-(LN) and hyaluronate (HA) in serum.The changes in and relationship between TNF-alpha,LN and HA were analyzed.The TNF-alphaand collagen III were determined using mmunohistochemical studies in liver tissues from 32 persons including 7 normal persons,3 patients with MCH,5 patients with SCH and 17 with LC.RESULTS:TNF-alpha,LN and HA levels in serum of CSH and LC patients were significantly higher than those in healthy controls (SCH:1.11plus minus0.59 130.7plus minus17.2,219.1plus minus121.3;LC:0.92plus minus0.66,156.8plus minus31.7,400.5plus minus183.7,P<0.05-0.01),which increased gradually,and correlated positively with each other in all patients with liver diseases (n=91,gamma=0.3149 P <0.01).TNF-alpha contents-showed a remarkably positive correlation with HA and LN levels in CMH and CSH (LN:n=40,gamma=0.3404,P <0.05 HA n=40,gamma=0.3847 P <0.05).The total collagen content of MCH,SCH and LC increased gradually in liver biopsy specimens.The number of TNF-alphapositive cells increased significantly in liver tissues from patients with SCH and LC (62%;45%;P <0.01).TNF-alphapositive cells were mainly located in the periportal areas.CONCLUSION:TNF-alphamay be related to liver fibrosis,and might promote liver fibrosis.
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PMID:Relationship between tumor necrosis factor-alphaand liver fibrosis. 1181 20

Collaborative studies have identified some genetic factors contributing to the development of severe forms of malaria and schistosomiasis. In Thailand, the TNF-alpha 5'-flanking region shows biallelic polymorphic sites at nucleotides -238, -308, -857, -863, and -1031, and seven alleles have been identified in patients from Myanmar. We found that the TNF promoter (TNFP)-D allele was significantly associated with cerebral malaria in populations from Karen (P < 0.0001, OR = 124.86) and ethnic Burma (P < 0.0001, OR = 34.50). In China, we have identified two major genes related to the severity of liver fibrosis, one an HLA class II gene, and the other the IL-13 gene. The frequency of the HLA-DRB5*0101 allele and that of the IL-13 promoter A/A (IL-13P- A/A) genotype were elevated in fibrotic patients, although the two genes are located on different chromosomes, chromosomes 6p and 5q, respectively. Subjects with both genotypes had odds ratios (OR = 24.5) much higher than the sum of the ratios for each individual genotype (OR = 5.1, 95% Confidence Interval 1.3-24.7 for HLA-DRB5*0101, OR = 3.1 95% CI 1.5 - 6.5 for IL-13P- A/A). That the effects of the two susceptibility markers are synergistic rather than additive, strongly suggests that the pathogenic Th2 response directly influences the prognosis of post-schistosomal liver fibrosis.
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PMID:Genetic factors associated with development of cerebral malaria and fibrotic schistosomiasis. 1250 99

The molecular mechanisms of acute hepatitis C virus (HCV) infection, end-stage hepatitis (cirrhosis), and hepatocellular carcinoma have been extensively studied, but little is known of the changes in liver gene expression during the early stages of liver fibrosis associated with chronic HCV infection, that is, the transition from normal liver (NL) of uninfected patients to the first stage of liver fibrosis (F1-CH-C). To obtain insight into the molecular pathogenesis of F1-CH-C, we used real-time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) to study the mRNA expression of 240 selected genes in liver tissue with F1-CH-C, in comparison with NL. The expression of 54 (22.5%) of the 240 genes was significantly different between F1-CH-C and NL; 46 genes were upregulated and 8 were downregulated in F1-CH-C. The most noteworthy changes in gene expression mainly affected the transcriptional network regulated by interferons (IFNs), including both IFN-alpha/beta-inducible genes (STAT1, STAT2, ISGF3G/IRF9, IFI27, G1P3, G1P2, OAS2, MX1) and IFN-gamma-inducible genes (CXCL9, CXCL10, CXCL11). Interesting, upregulation of IFN-alpha/beta-inducible genes (but not IFN-gamma-inducible genes) was independent of histological scores (grade and stage of fibrosis) and HCV characteristics (hepatic HCV mRNA levels and the HCV genotype), and was specific to HCV (as compared to hepatitis B virus (HBV)). Other genes dysregulated in F1-CH-C, albeit less markedly than IFN-alpha/beta- and IFN-gamma-inducible genes, were mainly involved in the activation of lymphocytes infiltrating the liver (IFNG, TNF, CXCL6, IL6, CCL8, CXCR3, CXCR4, CCR2), cell proliferation (p16/CDKN2A, MKI67, p14/ARF), extracellular matrix remodeling (MMP9, ITGA2), lymphangiogenesis (XLKD1/LYVE), oxidative stress (CYP2E1), and cytoskeleton microtubule organization (STMN2/SCG10). Thus, a limited number of signaling pathways, and particularly the transcriptional network regulated by interferons, are dysregulated in the first stage of HCV-induced liver fibrosis. Some of the genes identified here could form the basis for new approaches aimed at refining IFN-based therapies for chronic HCV infection.
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PMID:Molecular profiling of early stage liver fibrosis in patients with chronic hepatitis C virus infection. 1566 Nov 46

The aim of this study was to assess the antioxidant and antifibrotic effects of chronic administration of aqueous garlic extract on liver fibrosis induced by biliary obstruction in rats. Liver fibrosis was induced in male Wistar albino rats by bile duct ligation and scission (BDL). Aqueous garlic extract (AGE, 1 ml/kg, i.p., corresponding to 250 mg/kg) or saline was administered for 28 days. At the end of the experiment, rats were killed by decapitation. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) levels were determined to assess liver functions and tissue damage, respectively. Tumor necrosis factor-alpha (TNF-alpha) was also assayed in serum samples. Liver tissues were taken for determination of the free radicals, renal malondialdehyde (MDA) levels, an end product of lipid peroxidation; glutathione (GSH) levels, a key antioxidant; and myeloperoxidase (MPO) activity, as an indirect index of neutrophil infiltration. Hepatic collagen content, as a fibrosis marker was also determined. Serum AST, ALT, LDH, and TNF- alpha levels were elevated in the BDL group as compared to control group, while this increase was significantly decreased by AGE treatment. Hepatic GSH levels, significantly depressed by BDL, were elevated back to control levels in AGE-treated BDL group. Increases in tissue free radical and MDA levels and MPO activity due to BDL were reduced back to control levels by AGE treatment. Similarly, increased hepatic collagen content in the BDL rats was reduced to the level of the control group with AGE treatment. Since AGE administration alleviated the BDL-induced oxidative injury of the liver and improved the hepatic structure and function, it seems likely that AGE 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:Long-term administration of aqueous garlic extract (AGE) alleviates liver fibrosis and oxidative damage induced by biliary obstruction in rats. 1576 83

Chronic infections, such as hepatitis C, in the setting of rheumatic disorders pose a potential hindrance to optimal management because of possible complications linked to the institution of immune suppression, as well as the high incidence of hepatotoxicity associated with many of the disease-modifying antirheumatic drugs included in the conventional therapeutic regimens. In the setting of hepatitis C, however, the effect of TNFalpha blockade may be potentially beneficial because TNFalpha appears to be involved in the pathogenesis of liver fibrosis through the stimulation of apoptotic pathways. Data related to this subject are, unfortunately, still limited and without detailed information regarding the clinical progression of the rheumatic disorder. We report the cases of two patients, one with ankylosing spondylitis and one with psoriatic arthritis, who were efficiently treated long-term with anti-TNF agents for their rheumatic disease without any evidence of reactivation or flaring of their hepatitis C infection or deterioration of their liver function. Our results indicate that TNFalpha blockade is a highly efficient and uncompromising therapy in hepatitis C-affected individuals with connective tissue disorders. However, systematic, large-scale studies addressing the issue of safety of these new efficient drugs, i.e., monoclonal antibodies targeted against TNFalpha, in patients with chronic hepatitis C will be needed to properly assess the risks and benefits of this treatment in analogous cases.
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PMID:Inhibition of TNFalpha does not induce viral reactivation in patients with chronic hepatitis C infection: two cases. 1700 55

Methotrexate (MTX) toxicity in psoriatic disease was the focus of discussion at the 2007 Annual Meeting of the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA). Plenary presentations and results of a Web-based opinion survey of rheumatologists and dermatologists from GRAPPA, and others from New Zealand, Australia, and Canada, provided topics of discussion for small-group breakout sessions, including hepatotoxicity, alcohol use, fertility and pregnancy, and combination therapy. As a framework, topics were considered under headings: importance, knowledge deficit, sufficient data for a recommendation, and research agenda. Breakout session conclusions/consensus were as follows: (1) Data are insufficient to recommend routine serial liver biopsy to prevent MTX-induced liver fibrosis; further research is needed to establish whether serial liver chemistry tests or propeptide of type III collagen can detect hepatotoxicity without the need for liver biopsy. (2) Insufficient data are available to establish a dose-response relationship between alcohol use and MTX hepatotoxicity, so no safe limit of alcohol intake can be recommended. (3) Although cessation of MTX 3 months prior to conception is reasonable, inadequate data are available to specify duration or to quantify the risk of adverse fetal outcome; registries to track pregnancy outcome are potentially useful. (4) Combination therapy with anti-TNF agents or sulfasalazine is safe, but insufficient data are available for combinations with leflunomide or cyclosporine.
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PMID:Drug use and toxicity in psoriatic disease: focus on methotrexate. 1860 44

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