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Blesl A, Stadlbauer V. The Gut-Liver Axis in Cholestatic Liver Diseases. Nutrients 2021; 13:nu13031018. [PMID: 33801133 PMCID: PMC8004151 DOI: 10.3390/nu13031018] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 03/12/2021] [Accepted: 03/18/2021] [Indexed: 12/12/2022] Open
Abstract
The gut-liver axis describes the physiological interplay between the gut and the liver and has important implications for the maintenance of health. Disruptions of this equilibrium are an important factor in the evolution and progression of many liver diseases. The composition of the gut microbiome, the gut barrier, bacterial translocation, and bile acid metabolism are the key features of this cycle. Chronic cholestatic liver diseases include primary sclerosing cholangitis, the generic term secondary sclerosing cholangitis implying the disease secondary sclerosing cholangitis in critically ill patients and primary biliary cirrhosis. Pathophysiology of these diseases is not fully understood but seems to be multifactorial. Knowledge about the alterations of the gut-liver axis influencing the pathogenesis and the outcome of these diseases has considerably increased. Therefore, this review aims to describe the function of the healthy gut-liver axis and to sum up the pathological changes in these cholestatic liver diseases. The review compromises the actual level of knowledge about the gut microbiome (including the mycobiome and the virome), the gut barrier and the consequences of increased gut permeability, the effects of bacterial translocation, and the influence of bile acid composition and pool size in chronic cholestatic liver diseases. Furthermore, therapeutic implications and future scientific objectives are outlined.
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Affiliation(s)
- Andreas Blesl
- Division for Gastroenterology and Hepatology, Department of Internal Medicine, Medical University of Graz, 8036 Graz, Austria;
- Correspondence:
| | - Vanessa Stadlbauer
- Division for Gastroenterology and Hepatology, Department of Internal Medicine, Medical University of Graz, 8036 Graz, Austria;
- Center for Biomarker Research in Medicine (CBmed), 8010 Graz, Austria
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Klag T, Thomas M, Ehmann D, Courth L, Mailänder-Sanchez D, Weiss TS, Dayoub R, Abshagen K, Vollmar B, Thasler WE, Stange EF, Berg CP, Malek NP, Zanger UM, Wehkamp J. β-Defensin 1 Is Prominent in the Liver and Induced During Cholestasis by Bilirubin and Bile Acids via Farnesoid X Receptor and Constitutive Androstane Receptor. Front Immunol 2018; 9:1735. [PMID: 30100908 PMCID: PMC6072844 DOI: 10.3389/fimmu.2018.01735] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Accepted: 07/13/2018] [Indexed: 12/12/2022] Open
Abstract
Background & aims Knowledge about innate antimicrobial defense of the liver is limited. We investigated hepatic expression and regulation of antimicrobial peptides with focus on the human beta defensin-1 (hBD-1). Methods Radial diffusion assay was used to analyze antimicrobial activity of liver tissue. Different defensins including hBD-1 and its activator thioredoxin-1 (TXN) were analyzed in healthy and cholestatic liver samples by qPCR and immunostaining. Regulation of hBD-1 expression was studied in vitro and in vivo using bile duct-ligated mice. Regulation of hBD-1 via bilirubin and bile acids (BAs) was studied using siRNA. Results We found strong antimicrobial activity of liver tissue against Escherichia coli. As a potential mediator of this antimicrobial activity we detected high expression of hBD-1 and TXN in hepatocytes, whereas other defensins were minimally expressed. Using a specific antibody for the reduced, antimicrobially active form of hBD-1 we found hBD-1 in co-localization with TXN within hepatocytes. hBD-1 was upregulated in cholestasis in a graded fashion. In cholestatic mice hepatic AMP expression (Defb-1 and Hamp) was enhanced. Bilirubin and BAs were able to induce hBD-1 in hepatic cell cultures in vitro. Treatment with siRNA and/or agonists demonstrated that the farnesoid X receptor (FXR) mediates basal expression of hBD-1, whereas both constitutive androstane receptor (CAR) and FXR seem to be responsible for the induction of hBD-1 by bilirubin. Conclusion hBD-1 is prominently expressed in hepatocytes. It is induced during cholestasis through bilirubin and BAs, mediated by CAR and especially FXR. Reduction by TXN activates hBD-1 to a potential key player in innate antimicrobial defense of the liver.
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Affiliation(s)
- Thomas Klag
- Department of Internal Medicine I, University of Tübingen, Tübingen, Germany
| | - Maria Thomas
- Dr. Margarete Fischer-Bosch Institute for Clinical Pharmacology, Stuttgart and University of Tuebingen, Tuebingen, Germany
| | - Dirk Ehmann
- Department of Internal Medicine I, University of Tübingen, Tübingen, Germany
| | - Lioba Courth
- Department of Internal Medicine I, University of Tübingen, Tübingen, Germany
| | | | - Thomas S Weiss
- University Children Hospital (KUNO), Regensburg University Hospital, Regensburg, Germany
| | - Rania Dayoub
- University Children Hospital (KUNO), Regensburg University Hospital, Regensburg, Germany
| | - Kerstin Abshagen
- Rudolf-Zenker-Institute for Experimental Surgery, University Medicine Rostock, Rostock, Germany
| | - Brigitte Vollmar
- Rudolf-Zenker-Institute for Experimental Surgery, University Medicine Rostock, Rostock, Germany
| | - Wolfgang E Thasler
- Department of Surgery, Grosshadern Hospital, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Eduard F Stange
- Department of Internal Medicine I, University of Tübingen, Tübingen, Germany
| | - Christoph P Berg
- Department of Internal Medicine I, University of Tübingen, Tübingen, Germany
| | - Nisar P Malek
- Department of Internal Medicine I, University of Tübingen, Tübingen, Germany
| | - Ulrich M Zanger
- Dr. Margarete Fischer-Bosch Institute for Clinical Pharmacology, Stuttgart and University of Tuebingen, Tuebingen, Germany
| | - Jan Wehkamp
- Department of Internal Medicine I, University of Tübingen, Tübingen, Germany
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Abstract
Patients with cirrhosis and portal hypertension are at an increased risk of the development of circulatory dysfunction that may potentially result in multiple organ failure. Apart from the liver, this may involve the heart, lungs, kidneys, the immune system, the adrenal glands, and other organ systems. As the disease progresses, the circulation becomes hyperdynamic, and signs of cardiac, pulmonary, and renal dysfunction are observed, in addition to reduced survival. Infections and an altered cardiac function known as cirrhotic cardiomyopathy may be precipitators for the development of other complications such as hepatorenal syndrome. In patients with chronic organ dysfunction, various precipitating events may induce an acute-on-chronic renal failure and acute-on-chronic liver failure that negatively affect the prognosis. Future research on the pathophysiologic mechanisms of the complications and the precipitating factors is essential to understand the basics of the treatment of these challenging conditions. The aim of the present review is to focus on the development and precipitating factors of various organ failures in patients with decompensated cirrhosis.
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