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385 Publications visible to you, out of a total of 385
Second exposure to acetaminophen overdose is associated with liver fibrosis in mice

Abstract (Expand)

Repeated administration of hepatotoxicants is usually accompanied by liver fibrosis. However, the difference in response as a result of repeated exposures of acetaminophen (APAP) compared to a single … dose is not well-studied. Therefore, in the current study, the liver response after a second dose of APAP was investigated. Adult fasted Balb/C mice were exposed to two toxic doses of 300 mg/kg APAP, which were administered 72 h apart from each other. Subsequently, blood and liver from the treated mice were collected 24 h and 72 h after both APAP admin-istrations. Liver transaminase, i.e. alanine amino transferase (ALT) and aspartate amino transferase (AST) levels revealed that the fulminant liver damage was reduced after the second APAP administration compared to that observed at the same time point after the first treatment. These results correlated with the necrotic areas as indicated by histological analyses. Surprisingly, Picro Sirius Red (PSR) staining showed that the accumulation of extracel-lular matrix after the second dose coincides with the upregulation of some fibrogenic signatures, e.g., alpha smooth muscle actin. Non-targeted liver tissue metabolic profiling indicates that most alterations occur 24 h after the first dose of APAP. However, the levels of most metabolites recover to basal values over time. This organ adaptation process is also confirmed by the upregulation of antioxidative systems like e.g. superoxide dismutase and catalase. From the results, it can be concluded that there is a different response of the liver to APAP toxic doses, if the liver has already been exposed to APAP. A necroinflammatory process followed by a liver regeneration was observed after the first APAP exposure. However, fibrogenesis through the accumulation of extracellular matrix is observed after a second challenge. Therefore, further studies are required to mechanistically understand the so called “liver memory”

Author: Mohammad AlWahsh, Amnah Othman, Lama Hamadneh, Ahmad Telfah, Jörg Lambert, Suhair Hikmat, Amin Alassi, Fatma El Zahraa Mohamed, Roland Hergenröder, Tariq Al-Qirim, Steven Dooley, Seddik Hammad

Date Published: 6th Feb 2019

Publication Type: Not specified

Tick-tock hedgehog-mutual crosstalk with liver circadian clock promotes liver steatosis.

Abstract (Expand)

BACKGROUND & AIMS: The mammalian circadian clock controls various aspects of liver metabolism and integrates nutritional signals. Recently, we described Hedgehog (Hh) signaling as a novel regulator … of liver lipid metabolism. Herein, we investigated crosstalk between hepatic Hh signaling and circadian rhythm. METHODS: Diurnal rhythms of Hh signaling were investigated in liver and hepatocytes from mice with ablation of Smoothened (SAC-KO) and crossbreeds with PER2::LUC reporter mice. By using genome-wide screening, qPCR, immunostaining, ELISA and RNAi experiments in vitro we identified relevant transcriptional regulatory steps. Shotgun lipidomics and metabolic cages were used for analysis of metabolic alterations and behavior. RESULTS: Hh signaling showed diurnal oscillations in liver and hepatocytes in vitro. Correspondingly, the level of Indian Hh, oscillated in serum. Depletion of the clock gene Bmal1 in hepatocytes resulted in significant alterations in the expression of Hh genes. Conversely, SAC-KO mice showed altered expression of clock genes, confirmed by RNAi against Gli1 and Gli3. Genome-wide screening revealed that SAC-KO hepatocytes showed time-dependent alterations in various genes, particularly those associated with lipid metabolism. The clock/hedgehog module further plays a role in rhythmicity of steatosis, and in the response of the liver to a high-fat diet or to differently timed starvation. CONCLUSIONS: For the first time, Hh signaling in hepatocytes was found to be time-of-day dependent and to feed back on the circadian clock. Our findings suggest an integrative role of Hh signaling, mediated mainly by GLI factors, in maintaining homeostasis of hepatic lipid metabolism by balancing the circadian clock. LAY SUMMARY: The results of our investigation show for the first time that the Hh signaling in hepatocytes is time-of-day dependent, leading to differences not only in transcript levels but also in the amount of Hh ligands in peripheral blood. Conversely, Hh signaling is able to feed back to the circadian clock.

Authors: E. Marbach-Breitruck, M. Matz-Soja, U. Abraham, W. Schmidt-Heck, S. Sales, C. Rennert, M. Kern, S. Aleithe, L. Spormann, C. Thiel, R. Gerlini, K. Arnold, N. Kloting, R. Guthke, D. Rozman, R. Teperino, A. Shevchenko, A. Kramer, R. Gebhardt

Date Published: 4th Feb 2019

Publication Type: Not specified

Effect of alcohol on the interleukin 6-mediated inflammatory response in a new mouse model of acute-on-chronic liver injury

Abstract

Not specified

Authors: Ersin Karatayli, Rabea A. Hall, Susanne N. Weber, Steven Dooley, Frank Lammert

Date Published: 1st Feb 2019

Publication Type: Not specified

Common NOD2 Risk Variants as Major Susceptibility Factors for Bacterial Infections in Compensated Cirrhosis.

Abstract (Expand)

OBJECTIVES: Common nucleotide-binding oligomerization domain containing 2 (NOD2) gene variants have been associated with bacterial infections (BIs) in cirrhosis, in particular, spontaneous bacterial … peritonitis, and mortality. Our aim was to evaluate the independent association of NOD2 variants with BI according to the decompensation stage. METHODS: Consecutive patients with cirrhosis in 2 academic medical centers were included and genotyped for the NOD2 variants p.R702W, p.G908R, and c.3020insC. Electronic medical records were screened for BI (requiring antibiotic therapy) and past and present decompensation (as defined by variceal bleeding, encephalopathy, ascites, and/or jaundice). Clinically significant portal hypertension (CSPH) was assessed with liver stiffness and/or hepatic venous pressure gradient measurements. RESULTS: Overall, 735 patients were recruited (men 65%; interquartile age range 53-68 years). Alcoholic cirrhosis was the predominant etiology (n = 406, 55%), and most patients were in the decompensated stage (n = 531, 72%). In total, 158 patients (21%) carried at least one NOD2 variant. BIs were detected in 263 patients (36%), and NOD2 variants were associated with BI (odds ratio = 1.58; 95% confidence interval 1.11-2.27; P = 0.02). In compensated patients, the combination of NOD2 variants and presence of CSPH was the best independent predictors of BI, whereas other factors, such as spleen size and hemoglobin, and decompensations including hepatic encephalopathy or jaundice, gained relevance in decompensated patients. CONCLUSIONS: NOD2 risk variants are associated with BI in cirrhosis. The genetic effect on BI is strongest in compensated patients, whereas in decompensated patients their presence is less relevant. In this situation, CSPH becomes an independent factor associated with BI.

Authors: M. C. Reichert, C. Ripoll, M. Casper, R. Greinert, E. Vandieken, F. Grunhage, B. Appenrodt, A. Zipprich, F. Lammert

Date Published: 1st Feb 2019

Publication Type: Not specified

Dynamic Metabolic Zonation of the Hepatic Glucose Metabolism Is Accomplished by Sinusoidal Plasma Gradients of Nutrients and Hormones.

Abstract (Expand)

Being the central metabolic organ of vertebrates, the liver possesses the largest repertoire of metabolic enzymes among all tissues and organs. Almost all metabolic pathways are resident in the parenchymal … cell, hepatocyte, but the pathway capacities may largely differ depending on the localization of hepatocytes within the liver acinus-a phenomenon that is commonly referred to as metabolic zonation. Metabolic zonation is rather dynamic since gene expression patterns of metabolic enzymes may change in response to nutrition, drugs, hormones and pathological states of the liver (e.g., fibrosis and inflammation). This fact has to be ultimately taken into account in mathematical models aiming at the prediction of metabolic liver functions in different physiological and pathological settings. Here we present a spatially resolved kinetic tissue model of hepatic glucose metabolism which includes zone-specific temporal changes of enzyme abundances which are driven by concentration gradients of nutrients, hormones and oxygen along the hepatic sinusoids. As key modulators of enzyme expression we included oxygen, glucose and the hormones insulin and glucagon which also control enzyme activities by cAMP-dependent reversible phosphorylation. Starting with an initially non-zonated model using plasma profiles under fed, fasted and diabetic conditions, zonal patterns of glycolytic and gluconeogenetic enzymes as well as glucose uptake and release rates are created as an emergent property. We show that mechanisms controlling the adaptation of enzyme abundances to varying external conditions necessarily lead to the zonation of hepatic carbohydrate metabolism. To the best of our knowledge, this is the first kinetic tissue model which takes into account in a semi-mechanistic way all relevant levels of enzyme regulation.

Authors: N. Berndt, H. G. Holzhutter

Date Published: 12th Jan 2019

Publication Type: Journal

Data Formats for Systems Biology and Quantitative Modeling

Abstract (Expand)

Data standards support the reliable exchange of information, the interoperability of tools, and the reproducibility of scientific results. In systems biology standards are agreed ways of structuring, … describing, and associating models and data, as well as their respective parts, graphical visualization, and information about applied experimental or computational methods. Such standards also assist with describing how constituent parts interact together, or are linked, and how they are embedded in their environmental and experimental context. Here the focus will be on standards for formatting models and their content, and on metadata checklists and ontologies that support modeling.

Author: Martin Golebiewski

Date Published: 2019

Publication Type: InBook

Aged Abcb4-/- mice upon acute sublethal chemical insult recapitulate features of acute-on-chronic liver failure in patients

Abstract

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Authors: S Hammad, JG Hengstler, S Dooley

Date Published: 2019

Publication Type: Not specified

ECM1 is a gatekeeper that restrains TGF-β activation to maintain liver homeostasis and prevent fibrogenesis

Abstract

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Authors: S Dooley, W Fan, S Hammad, K Gould, T Longerich, T Liu, W Chen, C Liu, J Hou, J Jia, B Sun

Date Published: 2019

Publication Type: Not specified

Simultaneous isolation of parenchymal and non-parenchymal cells from healthy and diseased mice liver

Abstract

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Authors: B Dewidar, A Dropmann, K Gould, V Hartwig, C Dormann, S Dooley, S Hammad

Date Published: 2019

Publication Type: Not specified

Jagged-1 upregulation in stressed hepatocytes is crucial for liver regeneration

Abstract

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Authors: B Dewidar, S Hammad, MP Ebert, JG Hengstler, S Dooley

Date Published: 2019

Publication Type: Not specified

Cellular and nuclear hepatocyte ploidy represent a repository in regenerating livers

Abstract

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Authors: S Hammad, U Dahmen, A Othman, I Recklinghausen, JG Hengstler, U Klingmüller, S Dooley

Date Published: 2019

Publication Type: Not specified

Liver cell type specific discrimination of TGF-beta signaling and outcome in vitro and in vivo

Abstract

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Authors: M Han, ZC Nwosu, MP Ebert, S Hammad, S Dooley, C Meyer

Date Published: 2019

Publication Type: Not specified

CYP2E1 recovery is associated with a pericentral fibrosis pattern after repeated CCl4 insults

Abstract

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Authors: S Hammad, J Zhao, Y Yin, A Zaza, D Drasdo, JG Hengstler, S Dooley

Date Published: 2019

Publication Type: Not specified

Transcription factor TRIM33 controls liver progenitor cell towards hepatocyte differentiation through synergizing with phosphorylated Smad2/3 in liver cirrhosis

Abstract

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Authors: T Lin, S Wang, C Shao, X Yuan, F Wandrer, H Bantel, MP Ebert, H Ding, S Dooley, HL Weng

Date Published: 2019

Publication Type: Not specified

Maintenance of functional hepatocellular polarity determines recovery in acute-on-chronic liver failure

Abstract

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Authors: S Wang, R Feng, X Yuan, F Wandrer, MP Ebert, H Bantel, H Li, S Dooley, HL Weng

Date Published: 2019

Publication Type: Not specified

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