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Background and Aims: Activation of the inflammasome NLRP3 (NOD-, LRR- and pyrin domain containing 3) contributes to the development of non-alcoholic fatty liver disease (NAFLD) and progression to non-alcoholic steatohepatitis (NASH). Therefore, this study explored the therapeutic effects of a novel and selective NLRP3 antagonist in a murine dietary model of NASH. Methods: Groups of 12-week-old ApoE-/- mice were fed ad lib for 7 weeks with a methionine/choline deficient (MCD) and western diet (WD). After 3 weeks of diet-induced injury, mice were injected i. p. with the NLRP3 antagonist IFM-514 (100 mg/kg body weight) or vehicle (0.5% carmellose) every day, 5 days/week for a further 4 weeks. Several markers of inflammation, fibrosis and steatosis were evaluated. Whole transcriptome sequencing and panel RNA expression analysis (NanoString) were performed. Results: IFM-514 inhibited IL-1β production in mice challenged with 20 mg/kg lipopolysaccharide, and in mouse and human inflammatory cells in vitro. IFM-514 inhibited hepatic inflammation in the in vivo non-alcoholic steatohepatitis model assessed by H&E staining and in the hepatic gene expression of inflammasome-related proinflammatory cytokines. This effect was associated with significant reduction in caspase-1 activation. Similarly, IFM-514 was efficacious in vivo in MDC-fed ApoE-/- mice, markedly reducing portal pressure, Sirius red staining and 4-hydroxyproline content compared to vehicle-treated mice. Moreover, IFM-514 significantly reduced hepatic steatosis in MCD-fed ApoE-/- mice, as evidenced by NAFLD scores, oil red O staining, hepatic triglycerides and gene expression. In WD treated animals, similar trends in inflammation and fibrosis were observed, although not sufficient IFM-514 levels were reached. Conclusion: Overall, IFM-514 reduced liver inflammation and fibrosis, with mild effects on liver steatosis in experimental murine NASH. Blocking of NLRP3 may be an attractive therapeutic approach for NASH patients.
Purpose of the Review: This review aims to summarize the current knowledge of the extracellular matrix remodeling during hepatic fibrosis. We discuss the diverse interactions of the extracellular matrix with hepatic cells and the surrounding matrix in liver fibrosis, with the focus on the molecular pathways and the mechanisms that regulate extracellular matrix remodeling.
Recent Findings: The extracellular matrix not only provides structure and support for the cells, but also controls cell behavior by providing adhesion signals and by acting as a reservoir of growth factors and cytokines.
Summary: Hepatic fibrosis is characterized by an excessive accumulation of extracellular matrix. During fibrogenesis, the natural remodeling process of the extracellular matrix varies, resulting in the excessive accumulation of its components, mainly collagens. Signals released by the extracellular matrix induce the activation of hepatic stellate cells, which are the major source of extracellular matrix and most abundant myofibroblasts in the liver.
Background: The prevalence of metabolic liver diseases is increasing and approved pharmacological treatments are still missing. Many animal models of nonalcoholic fatty liver disease (NAFLD) show a full spectrum of fibrosis, inflammation and steatosis, which does not reflect the human situation since only up to one third of the patients develop fibrosis and nonalcoholic steatohepatitis (NASH). Methods: Seven week old C57Bl/J mice were treated with ethanol, Western diet (WD) or both. The animals’ liver phenotypes were determined through histology, immunohistochemistry, Western blotting, hepatic triglyceride content and gene expression levels. In a human cohort of 80 patients stratified by current alcohol misuse and body mass index, liver histology and gene expression analysis were performed. Results: WD diet and ethanol-treated animals showed severe steatosis, with high hepatic triglyceride content and upregulation of fatty acid synthesis. Mild fibrosis was revealed using Sirius-red stains and gene expression levels of collagen. Inflammation was detected using histology, immunohistochemistry and upregulation of proinflammatory genes. The human cohort of obese drinkers showed similar upregulation in genes related to steatosis, fibrosis and inflammation. Conclusions: We provide a novel murine model for early-stage fatty liver disease suitable for drug testing and investigation of pathophysiology.
Background: Pathogenesis of portal hypertension is multifactorial and includes pathologic intrahepatic angiogenesis, whereby TIPS insertion is an effective therapy of portal hypertension associated complications. While angiogenin is a potent contributor to angiogenesis in general, little is known about its impact on TIPS function over time. Methods: In a total of 118 samples from 47 patients, angiogenin concentrations were measured in portal and inferior caval vein plasma at TIPS insertion (each blood compartment n = 23) or angiographic intervention after TIPS (each blood compartment n = 36) and its relationship with patient outcome was investigated. Results: Angiogenin levels in the inferior caval vein were significantly higher compared to the portal vein (P = 0.048). Ten to 14 days after TIPS, inferior caval vein angiogenin level correlated inversely with the portal systemic pressure gradient (P<0.001), measured invasively during control angiography. Moreover, patients with TIPS revision during this angiography, showed significantly lower angiogenin level in the inferior caval vein compared to patients without TIPS dysfunction (P = 0.01). Conclusion: In cirrhosis patients with complications of severe portal hypertension, circulating levels of angiogenin are derived from the injured liver. Moreover, angiogenin levels in the inferior caval vein after TIPS may predict TIPS dysfunction.