Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0239946 (liver fibrosis)
 8,268 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Liver fibrosis and its end stage sequelae cirrhosis represent a major worldwide health problem. By definition progressive fibrosis occurs when the rate of matrix synthesis exceeds matrix degradation. Considerable evidence suggests that the hepatic stellate cell is central to the fibrotic process. During liver injury these cells transform from a quiescent retinoid filled phenotype to a proliferative myofibroblast like cell. In this 'activated' phenotype the HSC is the major source of the interstitial collagens, which characterize fibrosis. Recent work suggests that the HSCs are also a source of matrix degrading metalloproteinase (MMPs), indicating that, together with other cells, hepatic stellate cells (HSC) could participate in matrix remodelling. However, HSC activation in tissue culture models and in vivo is also associated with expression of the powerful MMP inhibitors: tissue inhibitors of metalloproteinases 1 and 2 (TIMP-1 and TIMP-2). TIMP expression has also been demonstrated in fibrotic human liver disease and animal models of liver fibrosis. TIMPs 1 and 2 may therefore promote progression of hepatic fibrosis through inhibition of matrix degradation.
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PMID:Tissue inhibitors of metalloproteinases in liver fibrosis. 907 40

Tissue inhibitor of metalloproteinases-1 (TIMP-1) has been shown to be increased in liver fibrosis development both in murine experimental models and human samples. However, the direct role of TIMP-1 during liver fibrosis development has not been defined. To address this issue, we developed transgenic mice overexpressing human TIMP-1 (hTIMP-1) in the liver under control of the albumin promoter/ enhancer. A model of CCl(4)-induced hepatic fibrosis was used to assess the extent of fibrosis development in TIMP-1 transgenic (TIMP-Tg) mice and control hybrid (Cont) mice. Without any treatment, overexpression of TIMP-1 itself did not induce liver fibrosis. There were no significant differences of pro-(alpha1)-collagen-I, (alpha2)-collagen-IV, and alpha-smooth muscle actin (alpha-SMA) mRNA expression in the liver between TIMP-Tg and Cont-mice, suggesting that overexpression of TIMP-1 itself did not cause hepatic stellate cell (HSC) activation. After 4-week treatment with CCl(4), however, densitometric analysis revealed that TIMP-Tg-mice had a seven-fold increase in liver fibrosis compared with the Cont-mice. The hepatic hydroxyproline content and serum hyaluronic acid were also significantly increased in TIMP-Tg-mice, whereas CCl(4)-induced liver dysfunction was not altered. An active form of matrix metalloproteinases-2 (MMP-2) level in the liver of TIMP-Tg-mice was decreased relative to that in Cont-mice because of the transgenic TIMP-1. Immunohistochemical analysis revealed that collagen-I and collagen-IV accumulation was markedly increased in the liver of CCl(4)-treated TIMP-Tg-mice with a pattern similar to that of alpha-SMA positive cells. These results suggest that TIMP-1 does not by itself result in liver fibrosis, but strongly promotes liver fibrosis development.
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PMID:Tissue inhibitor of metalloproteinases-1 promotes liver fibrosis development in a transgenic mouse model. 1109 31

The activated hepatic stellate cell (HSC) is central to liver fibrosis as the major source of collagens I and III and the tissue inhibitors of metalloproteinase-1 (TIMP-1). During spontaneous recovery from liver fibrosis, there is a decrease of TIMP expression, an increase in collagenase activity, and increased apoptosis of HSC, highlighting a potential role for TIMP-1 in HSC survival. In this report, we use tissue culture and in vivo models to demonstrate that TIMP-1 directly inhibits HSC apoptosis. TIMP-1 demonstrated a consistent, significant, and dose-dependent antiapoptotic effect for HSC activated in tissue culture and stimulated to undergo apoptosis by serum deprivation, cycloheximide exposure, and nerve growth factor stimulation. A nonfunctional mutated TIMP-1 (T2G mutant) in which all other domains are conserved did not inhibit apoptosis, indicating that inhibition of apoptosis was mediated through MMP inhibition. Synthetic MMP inhibitors also inhibited HSC apoptosis. Studies of experimental liver cirrhosis demonstrated that persistent expression of TIMP-1 mRNA determined by PCR correlated with persistence of activated HSC quantified by alpha smooth muscle actin staining, while in fibrosis, loss of activated HSC correlated with a reduction in TIMP-1 mRNA. We conclude that TIMP-1 inhibits apoptosis of activated HSC via MMP inhibition.
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PMID:Inhibition of apoptosis of activated hepatic stellate cells by tissue inhibitor of metalloproteinase-1 is mediated via effects on matrix metalloproteinase inhibition: implications for reversibility of liver fibrosis. 1179 25

It has been suggested that the tissue inhibitor of metalloproteinases-1 (TIMP-1) is involved in spontaneous resolution of liver fibrosis. The aim of this study was to investigate whether TIMP-1 altered spontaneous resolution of liver fibrosis in conjunction with matrix metalloproteinases (MMP) inhibition and hepatic stellate cell (HSC) activation. The livers of liver-targeted TIMP-1 transgenic (TIMP-Tg) and control hybrid (Cont) mice were harvested at 0, 3, 7, and 28 days following spontaneous recovery from CCl(4)-induced liver fibrosis. The extent of fibrosis resolution, MMP expression, alpha-smooth-muscle actin (alpha-SMA) positive cells, and procollagen-(I) messenger RNA (mRNA) in the liver were assessed at the respective periods in both groups. We also examined the effect of TIMP-1 on HSC apoptosis. The TIMP-Tg mice showed significantly attenuated resolution of spontaneous liver fibrosis compared with the Cont mice. The hydroxyproline content, number of alpha-SMA positive cells, and procollagen-(I) mRNA rapidly decreased with time in the Cont mice, whereas these markers were little changed in TIMP-Tg mice. The level of the active form of metalloproteinases-2 (MMP-2) in the TIMP-Tg mice was less than that in the Cont mice. TIMP-1 markedly decreased the nonparenchyma apoptotic cells in the liver fibrosis resolution model, and it also inhibited HSC apoptosis associated with suppression of caspase-3 activity in vitro. In conclusion, TIMP-1 significantly attenuated spontaneous resolution of liver fibrosis by the combination of a net reduction of the MMP activity and suppression of apoptosis in HSC.
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PMID:Tissue inhibitor of metalloproteinases-1 attenuates spontaneous liver fibrosis resolution in the transgenic mouse. 1229 32

Chronic hepatitis C virus (HCV) infection results in the development of liver fibrosis and cirrhosis in 20 to 25% of patients. The main task of the physician when examining a patient with a verified HCV infection is to identify the activity of inflammatory and necrotic processes in the liver, as well as the stage of fibrosis, and the reversibility of detected changes. Along with other clinical and laboratory parameters, this plays a major role in forecasting the course of hepatitis, as well as determines the therapeutic approach in each specific case. Liver biopsy remains the best way to assess the severity of chronic hepatitis C. The risk of developing cirrhosis depends on the stage (degree of fibrosis) and the grade (degree of inflammation and necrosis) observed in the initial liver biopsy. Non-invasive diagnostic approaches attempt to evaluate the serum markers of fibrogenesis. Biochemical markers of fibrosis scoring include thrombocyte counts, the prothrombin time, ratio of alaninaminotransferase (ALT) and aspartataminotransferase (AST) levels, the level of g-glutamyl transferase and the quantity of blood serum albumin. Another set of markers is based on the detection of molecular junctions that activate fibrosis, or participate in the generation of the liver extracellular matrix. The most applicable include hyaluronic acid (HA), type IV collagen (IV-C), N-terminal propeptide of type III procollagen (PIIIP), metalloproteinases (MMP), inhibitors of metalloproteinases (TIMP), and growth-transforming factor betta (GTFbeta). The review discusses the clinical significance of each of the criteria and possibility of their combination in the non-invasive monitoring of liver fibrosis.
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PMID:Invasive and non-invasive monitoring of hepatitis C virus-induced liver fibrosis: alternatives or complements? 1276 63

Liver fibrosis and cirrhosis involve multiple cellular and molecular events that lead to deposition of an excess of extracellular matrix proteins and increase the distortion of normal liver architecture. Etiologies include chronic viral hepatitis, alcohol abuse and drug toxicity. Degradation of these matrix proteins occurs predominantly as a result of a family of enzymes called metalloproteases (MMPs) that specifically degrade collagenous and non-collagenous substrates. Matrix degradation in the liver is due to the action of at least four of these enzymes: MMP-1, MMP-2, MMP-3 and MMP-9. In the fibrinolytic system, MMPs can be activated through proteolytic cleavage by the action of urokinase plasminogen activator; a second mechanism includes the same metalloproteases. This activity is regulated at many levels in the fibrinolytic system. The main regulator is the PAI-1. This molecule blocks the conversion of plasminogen into plasmin, and the MMP cannot be activated. At a second level, the inhibition is possible by binding to inhibitors called TIMP that can inhibit the proteolitic activity even when the MMPs had been previously activated by plasmin. During abnormal conditions, overexpression of these inhibitors is directed by the transforming growth factor-beta that in a fibrotic disease acts as an extremely important adverse factor.
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PMID:[Hepatic fibrosis: role of matrix metalloproteases and TGFbeta]. 1616 29

Hepatic fibrosis represents a process of healing and scarring in response to chronic liver injury. alpha-Melanocyte-stimulating hormone (alpha-MSH) is a 13-amino-acid peptide with potent anti-inflammatory effects. We have previously demonstrated that alpha-MSH gene therapy protects against thioacetamide (TAA)-induced acute liver failure. Therefore, the aim of this study is to investigate whether alpha-MSH gene therapy possesses antihepatic fibrogenic effect. Liver fibrosis was induced by long-term TAA administration in mice. alpha-Melanocyte-stimulating hormone expression plasmid was delivered via electroporation after liver fibrosis was established. Our results showed that alpha-MSH gene therapy attenuated liver fibrosis in TAA-treated mice. Reverse transcription polymerase chain reaction revealed that alpha-MSH gene therapy attenuated the liver transforming growth factor-beta1, collagen alpha1 and cell adhesion molecule mRNA upregulation. Following gene transfer, the expression of alpha-smooth muscle actin and cyclooxygenase-2 were both significantly attenuated. Further, alpha-MSH significantly increased matrix metalloproteinase (MMP), while tissue inhibitors of matrix metalloproteinase (TIMPs) were inactivated. In summary, alpha-MSH gene therapy reversed established liver fibrosis in mice and prevented the upregulated fibrogenic and pro-inflammatory gene responses after TAA administration. Its collagenolytic effect might be attributed to MMP and TIMP modulation. Hence, alpha-MSH gene therapy may be an effective therapeutic modality against liver fibrosis with potential clinical use.
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PMID:Electroporative alpha-MSH gene transfer attenuates thioacetamide-induced murine hepatic fibrosis by MMP and TIMP modulation. 1651 23

Quercetin and praziquantel were used to treat mice with hepatic fibrosis due to Schistosoma japonicum infection. Quercetin treatment obviously relieved the degree of hepatic fibrosis, significantly reduced the expression of immediate early gene, tissue inhibitor of metalloproteinase 1 (TIMP 1), types I and III collagen compared to the control. The expression of c-jun mRNA, type I and type III collagen were reduced significantly compared to the group treated with praziquantel, whereas no difference in the expression of c-fos mRNA and TIMP1 between the two groups, indicating that quercetin may have better effect on schistosomal liver fibrosis than praziquantel in the long term.
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PMID:[Inhibition of quercetin on liver fibrosis due to Schistosoma japonicum infection and on the expression of immediate early gene and metalloproteinase 1 inhibitor in liver tissue of mice]. 1686 18

Liver fibrosis is characterized by an abnormal hepatic accumulation of extracellular matrix (ECM) that results from both increased deposition and reduced degradation of collagen fibres. Fibrotic liver injury results in activation of the hepatic stellate cell (HSC). Surrogate markers are gradually being substituted for biomarkers that reflect the complex balance between synthesis and degradation of the extracellular matrix. Once the hepatic stellate cell is activated, the preceding matrix changes and recurrent injurious stimuli will perpetuate the activated state. The ECM directs cellular differentiation, migration, proliferation and fibrogenic activation or deactivation. The metabolism of the extracellular matrix is closely regulated by matrix metalloproteinases (MMP) and their specific tissue inhibitors (TIMP). Although liver biopsy combined with connective tissue stains has been a mainstay of diagnosis, there is a need for less invasive methods. These diagnostic markers should be considered in combination with liver function tests, ultrasonography and clinical manifestations.
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PMID:Genesis of hepatic fibrosis and its biochemical markers. 1860 66

Hyaluronic acid (HA) and tissue inhibitor of metalloproteinase 1 (TIMP-1) are reliable markers of liver fibrosis and are closely linked to the proinflammatory status. In this pilot cohort study, we attempted to identify a clinical score that would predict the severity of nonalcoholic fatty liver disease (NAFLD) based on clinical variables and serum markers of fibrosis and inflammation. The cohort included 46 patients with histologically confirmed NAFLD (76.1% male; mean age, 43+/-13 years; mean body mass index [BMI], 27.8+/-3.5). Serum transforming growth factor beta (TGF-beta), HA, TIMP, and matrix metalloproteinase (MMP) levels were measured with commercial enzyme-linked immunoassay (ELISA) kits. Demographic features and clinical and laboratory findings were subjected to univariate and multivariate binary logistic regression analysis to construct the mathematical model. Receiver operating characteristic curve (ROC) analysis was used to identify a threshold value for diagnosis of NASH and to assess its sensitivity and specificity. Serum levels of HA and TIMP-1 were statistically different in patients with nonalcoholic steatohepatitis (NASH) (P<0.05). Logistic regression analysis of several clinical variables indicated patient age as the only independent predictor of NASH (odds ratio [OR], 1.129, 95% confidence interval [CI], 1.019-1.251, P=0.020). The mathematical model constructed on the basis of these results included age, TIMP-1, and HA levels. A value of 148.27 or more identified patients with NASH with 85.7% sensitivity, 87.1% specificity, and negative and positive predictive values of 96.4% and 60%, respectively. This model seems to represent a reliable noninvasive tool for excluding the presence of NASH. If validated in larger prospective cohort studies, it might be useful for determining when a liver biopsy is actually warranted in patients with NAFLD.
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PMID:Serum levels of hyaluronic acid and tissue metalloproteinase inhibitor-1 combined with age predict the presence of nonalcoholic steatohepatitis in a pilot cohort of subjects with nonalcoholic fatty liver disease. 1976 63


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