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Van der Graaff D, Kwanten WJ, Couturier FJ, Govaerts JS, Verlinden W, Brosius I, D'Hondt M, Driessen A, De Winter BY, De Man JG, Michielsen PP, Francque SM. Severe steatosis induces portal hypertension by systemic arterial hyporeactivity and hepatic vasoconstrictor hyperreactivity in rats. J Transl Med 2018; 98:1263-1275. [PMID: 29326427 DOI: 10.1038/s41374-017-0018-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 11/30/2017] [Accepted: 12/13/2017] [Indexed: 12/27/2022] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) has become the most prevalent chronic liver disease. The presence of portal hypertension has been demonstrated in NAFLD prior to development of inflammation or fibrosis, and is a result of extrahepatic and intrahepatic factors, principally driven by vascular dysfunction. An increased intrahepatic vascular resistance potentially contributes to progression of NAFLD via intralobular hypoxia. However, the exact mechanisms underlying vascular dysfunction in NAFLD remain unknown. This study investigates systemic hemodynamics and both aortic and intrahepatic vascular reactivity in a rat model of severe steatosis. Wistar rats were fed a methionine-choline-deficient diet, inducing steatosis, or control diet for 4 weeks. In vivo hemodynamic measurements, aortic contractility studies, and in situ liver perfusion experiments were performed. The mean arterial blood pressure was lower and portal blood pressure was higher in steatosis compared to controls. The maximal contraction force in aortic rings from steatotic rats was markedly reduced compared to controls. While blockade of nitric oxide (NO) production did not reveal any differences, cyclooxygenase (COX) blockade reduced aortic reactivity in both controls and steatosis, whereas effects were more pronounced in controls. Effects could be attributed to COX-2 iso-enzyme activity. In in situ liver perfusion experiments, exogenous NO donation or endogenous NO stimulation reduced the transhepatic pressure gradient (THPG), whereas NO synthase blockade increased the THPG only in steatosis, but not in controls. Alpha-1-adrenergic stimulation and endothelin-1 induced a significantly more pronounced increase in THPG in steatosis compared to controls. Our results demonstrate that severe steatosis, without inflammation or fibrosis, induces portal hypertension and signs of a hyperdynamic circulation, accompanied by extrahepatic arterial hyporeactivity and intrahepatic vascular hyperreactivity. The arterial hyporeactivity seems to be NO-independent, but appears to be mediated by specific COX-2-related mechanisms. Besides, the increased intrahepatic vascular resistance in steatosis appears not to be NO-related but rather to vasoconstrictor hyperreactivity.
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Affiliation(s)
- Denise Van der Graaff
- Department of Gastroenterology and Hepatology, Antwerp University Hospital, Antwerp, Belgium.,Laboratory of Experimental Medicine and Pediatrics (LEMP), Division of Gastroenterology-Hepatology, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Wilhelmus J Kwanten
- Department of Gastroenterology and Hepatology, Antwerp University Hospital, Antwerp, Belgium.,Laboratory of Experimental Medicine and Pediatrics (LEMP), Division of Gastroenterology-Hepatology, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Filip J Couturier
- Laboratory of Experimental Medicine and Pediatrics (LEMP), Division of Gastroenterology-Hepatology, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Jesse S Govaerts
- Laboratory of Experimental Medicine and Pediatrics (LEMP), Division of Gastroenterology-Hepatology, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Wim Verlinden
- Department of Gastroenterology and Hepatology, Antwerp University Hospital, Antwerp, Belgium.,Laboratory of Experimental Medicine and Pediatrics (LEMP), Division of Gastroenterology-Hepatology, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Isabel Brosius
- Laboratory of Experimental Medicine and Pediatrics (LEMP), Division of Gastroenterology-Hepatology, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Michiel D'Hondt
- Laboratory of Experimental Medicine and Pediatrics (LEMP), Division of Gastroenterology-Hepatology, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Ann Driessen
- Department of Pathology, Antwerp University Hospital, Laboratory of Pathology, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Benedicte Y De Winter
- Laboratory of Experimental Medicine and Pediatrics (LEMP), Division of Gastroenterology-Hepatology, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Joris G De Man
- Laboratory of Experimental Medicine and Pediatrics (LEMP), Division of Gastroenterology-Hepatology, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Peter P Michielsen
- Department of Gastroenterology and Hepatology, Antwerp University Hospital, Antwerp, Belgium.,Laboratory of Experimental Medicine and Pediatrics (LEMP), Division of Gastroenterology-Hepatology, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Sven M Francque
- Department of Gastroenterology and Hepatology, Antwerp University Hospital, Antwerp, Belgium. .,Laboratory of Experimental Medicine and Pediatrics (LEMP), Division of Gastroenterology-Hepatology, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium.
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Yanguas SC, Cogliati B, Willebrords J, Maes M, Colle I, van den Bossche B, de Oliveira CPMS, Andraus W, Alves VAF, Leclercq I, Vinken M. Experimental models of liver fibrosis. Arch Toxicol 2015; 90:1025-1048. [PMID: 26047667 DOI: 10.1007/s00204-015-1543-4] [Citation(s) in RCA: 219] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 05/28/2015] [Indexed: 02/08/2023]
Abstract
Hepatic fibrosis is a wound healing response to insults and as such affects the entire world population. In industrialized countries, the main causes of liver fibrosis include alcohol abuse, chronic hepatitis virus infection and non-alcoholic steatohepatitis. A central event in liver fibrosis is the activation of hepatic stellate cells, which is triggered by a plethora of signaling pathways. Liver fibrosis can progress into more severe stages, known as cirrhosis, when liver acini are substituted by nodules, and further to hepatocellular carcinoma. Considerable efforts are currently devoted to liver fibrosis research, not only with the goal of further elucidating the molecular mechanisms that drive this disease, but equally in view of establishing effective diagnostic and therapeutic strategies. The present paper provides a state-of-the-art overview of in vivo and in vitro models used in the field of experimental liver fibrosis research.
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Affiliation(s)
- Sara Crespo Yanguas
- Department of In Vitro Toxicology and Dermato-Cosmetology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Brussels, Belgium
| | - Bruno Cogliati
- Department of Pathology, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil
| | - Joost Willebrords
- Department of In Vitro Toxicology and Dermato-Cosmetology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Brussels, Belgium
| | - Michaël Maes
- Department of In Vitro Toxicology and Dermato-Cosmetology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Brussels, Belgium
| | - Isabelle Colle
- Department of Hepato-Gastroenterology, Algemeen Stedelijk Ziekenhuis, Aalst, Belgium
| | - Bert van den Bossche
- Department of Abdominal Surgery and Hepato-Pancreatico-Biliary Surgery, Algemeen Stedelijk Ziekenhuis, Aalst, Belgium
| | | | - Wellington Andraus
- Laboratory of Medical Investigation, Department of Pathology, University of São Paulo School of Medicine, São Paulo, Brazil
| | | | - Isabelle Leclercq
- Laboratoire d'Hépato-Gastro-Entérologie, Institut de Recherche Expérimentale et Clinique, Université catholique de Louvain, Brussels, Belgium
| | - Mathieu Vinken
- Department of In Vitro Toxicology and Dermato-Cosmetology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Brussels, Belgium
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Noiret L, Baigent S, Jalan R. Arterial ammonia levels in cirrhosis are determined by systemic and hepatic hemodynamics, and by organ function: a quantitative modelling study. Liver Int 2014; 34:e45-55. [PMID: 24134128 DOI: 10.1111/liv.12361] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2013] [Accepted: 10/13/2013] [Indexed: 12/13/2022]
Abstract
BACKGROUND & AIMS Hyperammonaemia is a common complication of chronic liver failure. Two main factors are thought to underlie this complication: a loss of hepatic detoxification function and the development of portosystemic shunting. However, few studies have tried to quantify the importance of portosystemic shunting. Here, we used a theoretical approach to test the hypothesis that the development of portosystemic shunting is sufficient to cause hyperammonaemia in cirrhosis. METHODS Two mathematical models are developed. The first one describes the main vascular resistances of the circulation and is used to provide scenarios for the distributions of organ blood flow in cirrhosis, which are necessary to run the second model. The second model predicts arterial ammonia levels resulting from ammonia metabolism in gut, liver, kidney, muscle and brain, and the distribution of organ blood flow. RESULTS The fraction of gastrointestinal blood flow shunted through collaterals was estimated to be 41% in mild cirrhosis, 69% in moderate and 85% in severe cases. In the second model, the redistribution of organ blood flow associated with severe cirrhosis was sufficient to cause hyperammonaemia, even when the hepatic detoxification function and the ammonia production were set to normal. CONCLUSIONS The model indicates that the development of portosystemic shunting in cirrhosis is sufficient to cause hyperammonaemia. Interventions that reduce the fraction of shunting may be future targets of therapy to control severity of hyperammonaemia.
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Bin WT, Ma LM, Xu Q, Shi XL. Embryonic hepatocyte transplantation for hepatic cirrhosis: Efficacy and mechanism of action. World J Gastroenterol 2012; 18:309-22. [PMID: 22294837 PMCID: PMC3261526 DOI: 10.3748/wjg.v18.i4.309] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Revised: 07/14/2011] [Accepted: 07/21/2011] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the efficacy and mechanism of action of allogeneic embryonic hepatocyte transplantation for the treatment of hepatic cirrhosis.
METHODS: Rat embryonic hepatocytes were characterized by examining cell markers. Wistar rats with CCl4-induced cirrhosis were randomly divided into two groups: a model group receiving continuous CCl4, and a cell transplantation group receiving continuous CCl4 and transplanted with embryonic fluorescent-labeled hepatocytes. In addition, a normal control group was composed of healthy rats. All rats were sacrificed after 2 wk following the initiation of the cell transplant. Ultrasound, pathological analyses and serum biochemical tests were used to evaluate the efficacy of embryonic hepatocyte transplantation. To analyze the recovery status of cirrhotic hepatocytes and the signaling pathways influenced by embryonic hepatocyte transplantation, real-time polymerase chain reaction was performed to examine the mRNA expression of stellate activation-associated protein (STAP), c-myb, α smooth muscle actin (α-SMA) and endothelin-1 (ET-1). Western blotting and immunohistochemistry were employed to detect α-SMA and ET-1 protein expression in hepatic tissues.
RESULTS: Gross morphological, ultrasound and histopathological examinations, serum biochemical tests and radioimmunoassays demonstrated that hepatic cirrhosis was successfully established in the Wistar rats. Stem cell factor receptor (c-kit), hepatocyte growth factor receptor (c-Met), Nestin, α fetal protein, albumin and cytokeratin19 markers were observed in the rat embryonic hepatocytes. Following embryonic hepatocyte transplantation, there was a significant reversal in the gross appearance, ultrasound findings, histopathological properties, and serum biochemical parameters of the rat liver. In addition, after the activation of hepatic stellate cells and STAP signaling, α-SMA, c-myb and ET-1 mRNA levels became significantly lower than in the untreated cirrhotic group (P < 0.05). These levels, however, were not statistically different from those of the normal healthy group. Immunohistochemical staining and Western blot analyses revealed that α-SMA and ET-1 protein expression levels in the transplantation group were significantly lower than in the untreated cirrhotic group, but being not statistically different from the normal group.
CONCLUSION: Transplantation of embryonic hepatocytes in rats has therapeutic effects on cirrhosis. The described treatment may significantly reduce the expression of STAP and ET-1.
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de Souza Rossignoli P, Pereira OCM, Chies AB. Orchidectomy enhances the effects of phenylephrine in rat isolated portal vein. Clin Exp Pharmacol Physiol 2009; 37:368-74. [PMID: 19843099 DOI: 10.1111/j.1440-1681.2009.05313.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
1. Orchidectomy results in long-term testosterone deprivation similar to that observed in male clinical pathologies, such as hypogonadism and age-related reductions in plasma testosterone concentrations. Although the vascular effects of these sorts of hormone deprivations are known in arteries, they have not been studied to the same extent in veins. 2. The aim of the present study was to determine the effect of orchidectomy, with or without subsequent testosterone replacement (started 23 days after orchidectomy; 10 mg/kg, i.m., testosterone propionate once every 5 days for 3 weeks), on responses of rat isolated portal veins and vena cavae to exogenous phenylephrine (PE). Isolated vessels were mounted in an organ bath and concentration-response curves constructed to PE (10(-10)-10(-4) mol/L), endothelin (ET; 10(-10)-10(-5) mol/L) and KCl (10(-2)-1.2 x 10(-1) mol/L; as a control). 3. Orchidectomy had no effect on contractile responses of either the portal vein or vena cava to KCl. However, orchidectomy enhanced the maximum response (R(max)) of the portal vein, but not the vena cava, to PE. Testosterone replacement had no effect on these responses. The effects of orchidectomy on the R(max) to PE in portal veins were not altered by the nitric oxide synthase inhibitor N(G)-nitro-l-arginine methyl ester (10(-4) mol/L) alone or combined with 10(-5) mol/L indomethacin (a non-selective cyclo-oxygenase inhibitor), but they were abolished following treatment of isolated vessels with the ET(A) and ET(B) receptor antagonists BQ-123 and BQ-788 (both at 10(-6) mol/L). Orchidectomy did not alter portal vein responses to the application of exogenous ET. 4. The results of the present study indicate that orchidectomy-induced decreases in plasma testosterone can increase the venoconstrictor effects of PE on the portal vein and that this effect involves activation of both ET(A) and ET(B) receptors by locally produced ET.
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