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Zipprich A, Gittinger F, Winkler M, Dollinger MM, Ripoll C. Effect of ET-A blockade on portal pressure and hepatic arterial perfusion in patients with cirrhosis: A proof of concept study. Liver Int 2021; 41:554-561. [PMID: 33295121 DOI: 10.1111/liv.14757] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 11/12/2020] [Accepted: 11/25/2020] [Indexed: 12/31/2022]
Abstract
BACKGROUND/AIM Endothelin causes vasoconstriction via the endothelin-A receptor (ET-A) in the intrahepatic circulation in cirrhosis and its increase leads to portal hypertension. The aim of the study was to investigate the acute effect of a selective ET-A antagonist in patients with portal hypertension and cirrhosis. METHODS Proof-of-concept study with two different substudies: (a) local intrahepatic administration of the ET-A antagonist BQ 123 and (b) systemic oral administration of the ET-A antagonist Ambrisentan. Portal pressure was determined by hepatic venous pressure gradient (HVPG, both substudies) and hepatic arterial blood flow (HABF) by intra-arterial Doppler measurements (substudy 1) before and under the ET-A antagonist. Systemic haemodynamic parameters were measured in substudy 2. RESULTS Twelve patients (Child-Pugh [CP] B/C n = 7/5) were included in substudy 1 and 14 patients (CP A/B/C n = 4/6/4) in substudy 2. The relative decrease in HVPG was -12.5% (IQR: -40% to 0%; P = .05) in substudy 1 and -5.0% (IQR: -11.5% to 0%; P = .01) in substudy 2. Substudy 1 revealed higher decrease in HVPG in CP B patients. HABF increased significantly and patients without portal pressure decrease showed a higher increase of HABF. Substudy 2 showed a slight decrease in the mean arterial pressure without changes of other systemic haemodynamic parameters. CONCLUSION Administration of a selective ET-A antagonist decreases the portal pressure in cirrhotic patients. This decrease was higher in CP B patients and the non-responders showed a higher increase in hepatic arterial flow. Selective ET-A antagonists might be a future treatment option in patients with portal hypertension.
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Affiliation(s)
- Alexander Zipprich
- First Department of Internal Medicine, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany
| | - Fleur Gittinger
- First Department of Internal Medicine, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany
| | - Matthias Winkler
- First Department of Internal Medicine, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany
| | - Matthias M Dollinger
- First Department of Internal Medicine, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany
| | - Cristina Ripoll
- First Department of Internal Medicine, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany
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2
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Schreier B, Wolf A, Hammer S, Pohl S, Mildenberger S, Rabe S, Gekle M, Zipprich A. The selective mineralocorticoid receptor antagonist eplerenone prevents decompensation of the liver in cirrhosis. Br J Pharmacol 2018; 175:2956-2967. [PMID: 29682743 DOI: 10.1111/bph.14341] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 01/27/2018] [Accepted: 03/08/2018] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND AND PURPOSE The mineralocorticoid receptor (MR) contributes to fibrosis in various tissues, and MR antagonists, like eplerenone, are used to prevent fibrosis. The role of MR antagonists in hepatic fibrosis and cirrhosis is unknown. Here, we investigated the role of MRs and eplerenone in cirrhosis development. EXPERIMENTAL APPROACH Liver fibrosis (5 weeks) and cirrhosis, without (8 weeks) and with ascites (12 weeks), were induced by CCl4 in rats and comprehensively analysed. The effect of eplerenone on the development of cirrhosis with ascites was assessed. MR expression, cellular and subcellular distribution and impact of hypoxia were investigated in vivo and ex vivo. Primary rat hepatocytes and cell lines were used to investigate MR trafficking and transcriptional activity mechanistically. KEY RESULTS In cirrhosis with ascites, MR mRNA and protein expressions were reduced in hepatocytes of hypoxic areas. While in normoxic areas MRs were mainly cytosolic, the remaining MRs in hypoxic areas were mainly localized in the nuclei, indicating activation followed by translocation and degradation. Accordingly, eplerenone treatment prevented nuclear MR translocation and the worsening of cirrhosis. Exposing hepatocytes ex vivo to hypoxia induced nuclear MR translocation and enhanced transcriptional MR activity at response elements of the NF-κB pathway. CONCLUSIONS AND IMPLICATIONS We showed for the first time that hypoxia leads to a pathogenetic ligand-independent activation of hepatic MRs during cirrhosis resulting in their nuclear translocation and transcriptional activation of the NF-κB pathway. Treatment with eplerenone prevented the worsening of cirrhosis by blocking this ligand-independent activation of the MR.
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Affiliation(s)
- Barbara Schreier
- Julius Bernstein Institute of Physiology, Medical School, Martin Luther University of Halle-Wittenberg, Halle, Germany
| | - Anja Wolf
- Laboratory of Molecular Hepatology, Clinic of Internal Medicine I, Martin Luther University of Halle-Wittenberg, Halle, Germany.,Julius Bernstein Institute of Physiology, Medical School, Martin Luther University of Halle-Wittenberg, Halle, Germany
| | - Stefanie Hammer
- Laboratory of Molecular Hepatology, Clinic of Internal Medicine I, Martin Luther University of Halle-Wittenberg, Halle, Germany
| | - Sabine Pohl
- Laboratory of Molecular Hepatology, Clinic of Internal Medicine I, Martin Luther University of Halle-Wittenberg, Halle, Germany
| | - Sigrid Mildenberger
- Julius Bernstein Institute of Physiology, Medical School, Martin Luther University of Halle-Wittenberg, Halle, Germany
| | - Sindy Rabe
- Julius Bernstein Institute of Physiology, Medical School, Martin Luther University of Halle-Wittenberg, Halle, Germany
| | - Michael Gekle
- Julius Bernstein Institute of Physiology, Medical School, Martin Luther University of Halle-Wittenberg, Halle, Germany
| | - Alexander Zipprich
- Laboratory of Molecular Hepatology, Clinic of Internal Medicine I, Martin Luther University of Halle-Wittenberg, Halle, Germany
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Baldensperger T, Jost T, Zipprich A, Glomb MA. Novel α-Oxoamide Advanced-Glycation Endproducts within the N 6-Carboxymethyl Lysine and N 6-Carboxyethyl Lysine Reaction Cascades. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:1898-1906. [PMID: 29436827 DOI: 10.1021/acs.jafc.7b05813] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The highly reactive α-dicarbonyl compounds glyoxal and methylglyoxal are major precursors of posttranslational protein modifications in vivo. Model incubations of N2-t-Boc-lysine and either glyoxal or methylglyoxal were used to further elucidate the underlying mechanisms of the N6-carboxymethyl lysine and N6-carboxyethyl lysine reaction cascades. After independent synthesis of the authentic reference standards, we were able to detect N6-glyoxylyl lysine and N6-pyruvoyl lysine for the first time by HPLC-MS2 analyses. These two novel amide advanced-glycation endproducts were exclusively formed under aerated conditions, suggesting that they were potent markers for oxidative stress. Analogous to the well-known Strecker degradation pathway, leading from amino acids to Strecker acids, the oxidation of an enaminol intermediate is suggested to be the key mechanistic step. A highly sensitive workup for the determination of AGEs in tissues was developed. In support of our hypothesis, the levels of N6-glyoxylyl lysine and N6-pyruvoyl lysine in rat livers indeed correlated with liver cirrhosis and aging.
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Affiliation(s)
- Tim Baldensperger
- Institute of Chemistry, Food Chemistry, Martin-Luther-University Halle-Wittenberg , Kurt-Mothes-Strasse 2, 06120 Halle/Saale, Germany
| | - Tobias Jost
- Institute of Chemistry, Food Chemistry, Martin-Luther-University Halle-Wittenberg , Kurt-Mothes-Strasse 2, 06120 Halle/Saale, Germany
| | - Alexander Zipprich
- Department of Internal Medicine I, Martin-Luther-University Halle-Wittenberg , Ernst-Grube-Strasse 40, 06120 Halle/Saale, Germany
| | - Marcus A Glomb
- Institute of Chemistry, Food Chemistry, Martin-Luther-University Halle-Wittenberg , Kurt-Mothes-Strasse 2, 06120 Halle/Saale, Germany
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4
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Fortea JI, Zipprich A, Fernandez-Mena C, Puerto M, Bosoi CR, Almagro J, Hollenbach M, Bañares J, Rodríguez-Sánchez B, Cercenado E, Clément MA, Rose CF, Bañares R, Vaquero J, Ripoll C. Enoxaparin does not ameliorate liver fibrosis or portal hypertension in rats with advanced cirrhosis. Liver Int 2018; 38:102-112. [PMID: 28665498 DOI: 10.1111/liv.13510] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 06/26/2017] [Indexed: 02/13/2023]
Abstract
BACKGROUND & AIMS Recent studies suggest that heparins reduce liver fibrosis and the risk of decompensation of liver disease. Here, we evaluated the effects of enoxaparin in several experimental models of advanced cirrhosis. METHODS Cirrhosis was induced in male Sprague-Dawley (SD) rats by: (i) Oral gavage with carbon tetrachloride (CCl4ORAL ), (ii) Bile duct ligation (BDL) and (iii) CCl4 inhalation (CCl4INH ). Rats received saline or enoxaparin s.c. (40 IU/Kg/d or 180 IU/Kg/d) following various protocols. Blood biochemical parameters, liver fibrosis, endothelium- and fibrosis-related genes, portal pressure, splenomegaly, bacterial translocation, systemic inflammation and survival were evaluated. Endothelial dysfunction was assessed by in situ bivascular liver perfusions. RESULTS Enoxaparin did not ameliorate liver function, liver fibrosis, profibrogenic gene expression, portal hypertension, splenomegaly, ascites development and infection, serum IL-6 levels or survival in rats with CCl4ORAL or BDL-induced cirrhosis. Contrarily, enoxaparin worsened portal pressure in BDL rats and decreased survival in CCl4ORAL rats. In CCl4INH rats, enoxaparin had no effects on hepatic endothelial dysfunction, except for correcting the hepatic arterial dysfunction when enoxaparin was started with the CCl4 exposure. In these rats, however, enoxaparin increased liver fibrosis and the absolute values of portal venous and sinusoidal resistance. CONCLUSIONS Our results do not support a role of enoxaparin for improving liver fibrosis, portal hypertension or endothelial dysfunction in active disease at advanced stages of cirrhosis. These disease-related factors and the possibility of a limited therapeutic window should be considered in future studies evaluating the use of anticoagulants in cirrhosis.
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Affiliation(s)
- José I Fortea
- Laboratorio Investigación Hepatología y Gastroenterología, HGU Gregorio Marañón, Madrid, Spain.,Instituto Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain
| | - Alexander Zipprich
- Innere Medizin I, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
| | - Carolina Fernandez-Mena
- Laboratorio Investigación Hepatología y Gastroenterología, HGU Gregorio Marañón, Madrid, Spain.,Instituto Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain
| | - Marta Puerto
- Laboratorio Investigación Hepatología y Gastroenterología, HGU Gregorio Marañón, Madrid, Spain.,Instituto Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain.,CIBERehd, Madrid, Spain
| | - Cristina R Bosoi
- Hepato-neuro laboratory, CRCHUM, Université de Montréal, Montréal, Canada
| | - Jorge Almagro
- Laboratorio Investigación Hepatología y Gastroenterología, HGU Gregorio Marañón, Madrid, Spain.,Instituto Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain
| | - Marcus Hollenbach
- Innere Medizin I, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
| | - Juan Bañares
- Laboratorio Investigación Hepatología y Gastroenterología, HGU Gregorio Marañón, Madrid, Spain.,Instituto Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain
| | - Belén Rodríguez-Sánchez
- Instituto Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain.,Microbiología Clínica y Enfermedades Infecciosas, HGU Gregorio Marañón, Madrid, Spain.,CIBERES, Madrid, Spain
| | - Emilia Cercenado
- Instituto Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain.,Microbiología Clínica y Enfermedades Infecciosas, HGU Gregorio Marañón, Madrid, Spain
| | - Marc-André Clément
- Hepato-neuro laboratory, CRCHUM, Université de Montréal, Montréal, Canada
| | - Christopher F Rose
- Hepato-neuro laboratory, CRCHUM, Université de Montréal, Montréal, Canada
| | - Rafael Bañares
- Laboratorio Investigación Hepatología y Gastroenterología, HGU Gregorio Marañón, Madrid, Spain.,Instituto Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain.,CIBERehd, Madrid, Spain.,Facultad de Medicina, Universidad Complutense, Madrid, Spain
| | - Javier Vaquero
- Laboratorio Investigación Hepatología y Gastroenterología, HGU Gregorio Marañón, Madrid, Spain.,Instituto Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain.,CIBERehd, Madrid, Spain
| | - Cristina Ripoll
- Laboratorio Investigación Hepatología y Gastroenterología, HGU Gregorio Marañón, Madrid, Spain.,Instituto Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain.,Innere Medizin I, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany.,CIBERehd, Madrid, Spain
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5
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Brückner S, Zipprich A, Hempel M, Thonig A, Schwill F, Roderfeld M, Roeb E, Christ B. Improvement of portal venous pressure in cirrhotic rat livers by systemic treatment with adipose tissue–derived mesenchymal stromal cells. Cytotherapy 2017; 19:1462-1473. [DOI: 10.1016/j.jcyt.2017.09.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 09/01/2017] [Accepted: 09/05/2017] [Indexed: 02/07/2023]
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Hollenbach M, Thonig A, Pohl S, Ripoll C, Michel M, Zipprich A. Expression of glyoxalase-I is reduced in cirrhotic livers: A possible mechanism in the development of cirrhosis. PLoS One 2017; 12:e0171260. [PMID: 28231326 PMCID: PMC5322979 DOI: 10.1371/journal.pone.0171260] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 01/17/2017] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND High concentrations of methylglyoxal (MGO) cause cytotoxiticy via formation of advanced glycation endproducts (AGEs) and inflammation. MGO is detoxificated enzymatically by glyoxalase-I (Glo-I). The aim of this study was to analyze the role of Glo-I during the development of cirrhosis. METHODS In primary hepatocytes, hepatic stellate cells (pHSC) and sinusoidal endothelial cells (pLSEC) from rats with early (CCl4 8wk) and advanced cirrhosis (CCl4 12wk) expression and activity of Glo-I were determined and compared to control. LPS stimulation (24h; 100ng/ml) of HSC was conducted in absence or presence of the partial Glo-I inhibitor ethyl pyruvate (EP) and the specific Glo-I inhibitor BrBzGSHCp2. MGO, inflammatory and fibrotic markers were measured by ELISA and Western blot. Additional rats were treated with CCl4 ± EP 40mg/kg b.w. i.p. from wk 8-12 and analyzed with sirius red staining and Western blot. RESULTS Expression of Glo-I was significantly reduced in cirrhosis in whole liver and primary liver cells accompanied by elevated levels of MGO. Activity of Glo-I was reduced in cirrhotic pHSC and pLSEC. LPS induced increases of TNF-α, Nrf2, collagen-I, α-SMA, NF-kB and pERK of HSC were blunted by EP and BrBzGSHCp2. Treatment with EP during development of cirrhosis significantly decreased the amount of fibrosis (12wk CCl4: 33.3±7.3%; EP wk 8-12: 20.7±6.2%; p<0.001) as well as levels of α-SMA, TGF-β and NF-κB in vivo. CONCLUSIONS Our results show the importance of Glo-I as major detoxifying enzyme for MGO in cirrhosis. The reduced expression of Glo-I in cirrhosis demonstrates a possible explanation for increased inflammatory injury and suggests a "vicious circle" in liver disease. Blunting of the Glo-I activity decrease the amount of fibrosis in established cirrhosis and constitutes a novel target for antifibrotic therapy.
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Affiliation(s)
- Marcus Hollenbach
- Department of Internal Medicine I, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Antje Thonig
- Department of Internal Medicine I, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Sabine Pohl
- Department of Internal Medicine I, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Cristina Ripoll
- Department of Internal Medicine I, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Maurice Michel
- Department of Internal Medicine I, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Alexander Zipprich
- Department of Internal Medicine I, Martin Luther University Halle-Wittenberg, Halle, Germany
- * E-mail:
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Bosch J, Groszmann RJ, Shah VH. Evolution in the understanding of the pathophysiological basis of portal hypertension: How changes in paradigm are leading to successful new treatments. J Hepatol 2015; 62:S121-30. [PMID: 25920081 PMCID: PMC4519833 DOI: 10.1016/j.jhep.2015.01.003] [Citation(s) in RCA: 144] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 12/23/2014] [Accepted: 01/02/2015] [Indexed: 01/08/2023]
Abstract
Among the common complication of cirrhosis portal hypertension witnessed a major improvement of prognosis during the past decades. Principally due to the introduction of rational treatments based on new pathophysiological paradigms (concepts of thought) developed in the 1980s. The best example being the use of non-selective beta-blockers and of vasopressin analogs, somatostatin, and its analogs. Further refinement in the knowledge of the molecular mechanisms involved in the regulation of both the splanchnic and hepatic circulation has led to the emergence of new treatments, which are based on evidence that show not only structural but also vasoactive components increase the hepatic vascular resistance, as well as of angiogenesis. This knowledge and future improvements will most likely result in more effective treatment of portal hypertension and effective prevention of its complications in early stages.
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Affiliation(s)
- Jaume Bosch
- Hospital Clínic-IDIBAPS, University of Barcelona and Centro de Investigación, Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Barcelona, Spain.
| | | | - Vijay H Shah
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA
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Moeller M, Thonig A, Pohl S, Ripoll C, Zipprich A. Hepatic arterial vasodilation is independent of portal hypertension in early stages of cirrhosis. PLoS One 2015; 10:e0121229. [PMID: 25793622 PMCID: PMC4368541 DOI: 10.1371/journal.pone.0121229] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 01/29/2015] [Indexed: 12/17/2022] Open
Abstract
Introduction The compensatory increase in hepatic arterial flow with a decrease in portal venous flow is known as the hepatic arterial buffer response. In cirrhosis with elevated portal pressure, the vascular resistance of the hepatic artery is decreased. Whether this lower resistance of the hepatic artery is a consequence of portal hypertension or not remains unknown. Study Aim The aim of the study was to investigate the hepatic arterial resistance and response to vasoconstriction in cirrhosis without portal hypertension (normal portal resistance). Methods Cirrhosis was induced by CCl4-inhalation for 8 weeks (8W, normal portal resistance) and for 12–14 weeks (12W, elevated portal resistance). Bivascular liver perfusion was performed at 8W or 12W and dose response curves of methoxamine were obtained in the presence or absence of LNMMA (nitric oxide synthase blocker). Vascular resistances of the hepatic artery (HAR), portal vein (PVR) and sinusoids (SVR) were measured. Western Blot (WB) and Immunohistochemistry (IHC) were done to measure eNOS and HIF 1a expression. Results HAR in both groups of cirrhotic animals (8W and 12W) were lower compared to controls. Dose response curves to methoxamine revealed lower HAR in both cirrhotic models (8W and 12W) regardless the magnitude of portal resistance. LNMMA corrected the dose response curves in cirrhosis (8W and 12W) to control. WB and IHC show increased protein expression of eNOS and HIF1a in 8W and 12W. Conclusion Hepatic arterial resistance is decreased in cirrhosis independent of portal resistance. Vasodilation of the hepatic artery in cirrhosis seems to be influenced by hypoxia rather than increase in portal resistance. Nitric oxide is the main vasodilator.
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Affiliation(s)
- Miriam Moeller
- First Department of Internal Medicine, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Antje Thonig
- First Department of Internal Medicine, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Sabine Pohl
- First Department of Internal Medicine, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Cristina Ripoll
- First Department of Internal Medicine, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Alexander Zipprich
- First Department of Internal Medicine, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
- * E-mail:
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9
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Hernández-Guerra M, de Ganzo ZA, González-Méndez Y, Salido E, Abreu P, Moreno M, Felipe V, Abrante B, Quintero E. Chronic intermittent hypoxia aggravates intrahepatic endothelial dysfunction in cirrhotic rats. Hepatology 2013; 57:1564-74. [PMID: 23174804 DOI: 10.1002/hep.26152] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Accepted: 11/01/2012] [Indexed: 12/17/2022]
Abstract
UNLABELLED Chronic intermittent hypoxia (CIH) occurs with obstructive sleep apnea syndrome (OSAS) and provokes systemic endothelial dysfunction, which is associated with oxidative stress and low nitric oxide (NO) bioavailability. Cirrhotic livers exhibit intrahepatic endothelial dysfunction, which is characterized by an impaired endothelium-dependent response to vasodilators and hyperresponse to vasoconstrictors. We hypothesized that CIH may also contribute to intrahepatic endothelial dysfunction in cirrhosis. Normal and cirrhotic rats were exposed for 14 days to repetitive cycles of CIH mimicking OSAS in humans, or caged with room air (handled controls [HC]). Hepatic endothelial function was assessed in isolated and perfused rat livers by dose-response curves to acetylcholine (ACh) and methoxamine (Mtx). In a group of cirrhotic rats, in vivo systemic and hepatic hemodynamic parameters were evaluated at baseline and after volume expansion. In addition, liver samples were obtained to assess endothelial nitric oxide synthase (eNOS), phosphorylated eNOS (p-eNOS), NO bioavailability, and nitrotyrosinated proteins as a marker of oxidative stress. Cirrhotic rats exposed to CIH exhibited an attenuated vasodilatory response to ACh and hyperresponse to Mtx compared with HC rats. During volume expansion, similar portal pressure increases were observed in CIH and HC rats, although the mean arterial pressure increase was lower after CIH. These functional responses were associated with the presence of increased hepatic oxidative stress without changes in p-eNOS after CIH exposure. In normal rats, no hemodynamic changes were found. CONCLUSION CIH exacerbates intrahepatic endothelial dysfunction in cirrhotic rats, which is associated with increased oxidative stress that may reduce NO bioavailability. Clinical studies are needed to assess whether OSAS contributes to endothelial impairment in human patients with cirrhosis.
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Morphological and biomechanical remodelling of the hepatic artery in a swine model of portal hypertension. Hepatol Int 2011; 6:631-8. [PMID: 21948212 DOI: 10.1007/s12072-011-9302-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Accepted: 07/18/2011] [Indexed: 10/17/2022]
Abstract
OBJECTIVES To obtain the biomechanical and morphological remodelling of hepatic arteries in swine with portal hypertension. METHODS A number of 20 white pigs was used, of which 14 were subjected to liver cirrhosis and portal hypertension (PHT) induced by carbon tetrachloride and pentobarbital; the rest were used as the control group. The biomechanical remodelling of the hepatic arteries was measured, namely, the incremental elastic modulus (E inc), pressure-strain elastic modulus (E p), volume elastic modulus (E v), the incremental compliance (C), the opening angle and the stained microstructural components of the vessels. RESULTS The percentages for the microstructural components and the histologic data significantly changed in the experimental group, three incremental elastic moduli (E inc, E p, and E v) of the experimental group were significantly larger than those of the control group (P < 0.05); the compliance of hepatic arteries decreased greatly (P < 0.05) too. The opening angle (OA) was considerably larger than that of control group (P < 0.05). CONCLUSIONS The study suggests that the morphological and biomechanical properties of swine hepatic arteries have changed significantly during the process of portal hypertension and that from biomechanical aspects, the hepatic arteries have also suffered from extensive remodelling, which in turn deteriorates the existing portal hypertension.
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Long-term ursodeoxycholate improves circulating redox changes in primary biliary cirrhotic patients. Clin Biochem 2011; 44:1400-4. [PMID: 21963381 DOI: 10.1016/j.clinbiochem.2011.09.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2011] [Revised: 09/08/2011] [Accepted: 09/09/2011] [Indexed: 02/08/2023]
Abstract
BACKGROUND AND AIMS Cholestasis is associated with systemic and hepatic oxidative and nitrosative stress; in this scenario, the conjugated hydrophilic bile salt ursodeoxycholate (UDCA) might play a protective role. METHODS Circulating oxidative and nitrosative stress markers were assessed in patients with primary biliary cirrhosis (PBC) before and during UDCA (15-20mg/kg/day) therapy. RESULTS In patients with stage I-II PBC, UDCA improved ALT and alkaline phosphatase levels and near normalized serum thioredoxin (1.97 ± 0.37 vs 2.41 ± 0.39 nmol/L), nitrotyrosine (15 ± 4 vs 22 ± 7 nmol/L), nitrosothiols (144 ± 28 vs 205 ± 84 nmol/L) and K-18 levels (162 ± 21 vs 228 ± 33 U/L). Conversely, less marked changes were noted in patients with stages III-IV who showed lower thioredoxin (1.01 ± 0.31 nmol/L), higher nitrosothiols (605 ± 64 nmol/L), nitrotyrosine (62 ± 13 nmol/L) and K-18 levels (521 ± 57 U/L). Overall, thioredoxin was inversely related with nitrotyrosine (r=-0.838, P<0.001) and K-18 (r=-0.838, P<0.001) levels. Nitrosothiols and K-18 were linearly and significantly related with nitrotyrosine (r=0.862, P<0.001; r=0.894, P<0.001, respectively). CONCLUSIONS Oxidative and nitrosative changes in patients with PBC are effectively counteracted by UDCA. The protective effect of UDCA, however, are limited to early disease stages and progressively diminishes with ongoing cholestasis.
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12
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Zipprich A, Mehal WZ, Ripoll C, Groszmann RJ. A distinct nitric oxide and adenosine A1 receptor dependent hepatic artery vasodilatatory response in the CCl-cirrhotic liver. Liver Int 2010; 30:988-94. [PMID: 20500549 PMCID: PMC3219754 DOI: 10.1111/j.1478-3231.2010.02278.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
UNLABELLED Increase of portal venous vascular resistance is counteracted by decrease of hepatic arterial vascular resistance (hepatic arterial buffer response). This process is mediated by adenosine in normal livers. In cirrhosis, hepatic arterial vascular resistance is decreased but the involvement of adenosine in this process is unknown. The aim of our study was to identify the signalling pathway responsible for the decreased hepatic arterial resistance in cirrhotic livers. METHODS Cirrhosis was induced by CCl(4). Using a bivascular liver perfusion dose-response curves to adenosine of the HA were performed in the presence and the absence of pan-adenosine blocker (8-SPT), A1 blocker (caffeine) or nitric oxide synthase-blocker (l-NMMA) after preconstriction with an alpha1-agonist (methoxamine). Western blot of the HA were used to measure the density of the A1 and A2a receptors. RESULTS Adenosine caused a dose dependent relaxation of the hepatic artery of both cirrhotic and control animals that were blocked in both groups by 8-SPT (P<0.02). The response to adenosine was greater in cirrhotic rats (P=0.016). Both l-NMMA (P=0.003) and caffeine reduced the response to adenosine in cirrhotic but not in control animals. Western blot analysis showed a higher density of A1 and a lower density of A2a receptor in cirrhotic animals (P<0.05). CONCLUSION The adenosine-induced vasodilatation of the HA is increased in cirrhotic rats suggesting a role for adenosine-NO in the decreased hepatic arterial vascular resistance found in cirrhosis. This significantly greater response in cirrhosis by the A1 receptor follows the same pathway that is seen in hypoxic conditions in extra-hepatic tissues.
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Affiliation(s)
- Alexander Zipprich
- Digestive Disease Section, Yale University School of Medicine, New Haven, CT, USA.
| | - Wajahat Z. Mehal
- Digestive Disease Section, Yale University School of Medicine, New Haven, CT, USA
| | - Cristina Ripoll
- Digestive Disease Section, Yale University School of Medicine, New Haven, CT, USA,Hepatic Hemodynamic Laboratory, Veterans Affairs Medical Center, West Haven, CT, USA
| | - Roberto J. Groszmann
- Digestive Disease Section, Yale University School of Medicine, New Haven, CT, USA,Hepatic Hemodynamic Laboratory, Veterans Affairs Medical Center, West Haven, CT, USA
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