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Ramkissoon R, Cao S, Shah VH. The Pathophysiology of Portal Hypertension. Clin Liver Dis 2024; 28:369-381. [PMID: 38945632 DOI: 10.1016/j.cld.2024.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
This article reviews the pathophysiology of portal hypertension that includes multiple mechanisms internal and external to the liver. This article starts with a review of literature describing the cellular and molecular mechanisms of portal hypertension, microvascular thrombosis, sinusoidal venous congestion, portal angiogenesis, vascular hypocontractility, and hyperdynamic circulation. Mechanotransduction and the gut-liver axis, which are newer areas of research, are reviewed. Dysfunction of this axis contributes to chronic liver injury, inflammation, fibrosis, and portal hypertension. Sequelae of portal hypertension are discussed in subsequent studies.
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Affiliation(s)
- Resham Ramkissoon
- Department of Gastroenterology & Hepatology, Mayo Clinic, 200 1st Street, SW, Rochester, MN 55902, USA
| | - Sheng Cao
- Mayo College of Medicine, Mayo Clinic, 200 1st Street, SW, Rochester, MN 55902, USA
| | - Vijay H Shah
- Department of Gastroenterology & Hepatology, Mayo Clinic, 200 1st Street, SW, Rochester, MN 55902, USA; Department of Internal Medicine, Mayo Clinic, 200 1st Street, SW, Rochester, MN 55902, USA.
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2
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Kudryavtseva O, Lyngsø KS, Jensen BL, Dimke H. Nitric oxide, endothelium-derived hyperpolarizing factor, and smooth muscle-dependent mechanisms contribute to magnesium-dependent vascular relaxation in mouse arteries. Acta Physiol (Oxf) 2024; 240:e14096. [PMID: 38258597 DOI: 10.1111/apha.14096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 09/27/2023] [Accepted: 01/01/2024] [Indexed: 01/24/2024]
Abstract
AIM Magnesium (Mg2+ ) is a vasorelaxant. The underlying physiological mechanisms driving this vasorelaxation remain unclear. Studies were designed to test the hypothesis that multiple signaling pathways including nitric oxide (NO) and endothelium-derived hyperpolarizing factor (EDHF) in endothelial cells as well as Ca2+ antagonization and TRPM7 channels in vascular smooth muscle cells mediate Mg2+ -dependent vessel relaxation. METHODS To uncover these mechanisms, force development was measured ex vivo in aorta rings from mice using isometric wire myography. Concentration responses to Mg2+ were studied in intact and endothelium-denuded aortas. Key findings were confirmed in second-order mesenteric resistance arteries perfused ex vivo using pressure myography. Effects of Mg2+ on NO formation were measured in Chinese Hamster Ovary (CHO) cells, isolated mesenteric vessels, and mouse urine. RESULTS Mg2+ caused a significant concentration-dependent relaxation of aorta rings. This relaxation was attenuated significantly in endothelium-denuded aortas. The endothelium-dependent portion was inhibited by NO and cGMP blockade but not by cyclooxygenase inhibition. Mg2+ stimulated local NO formation in CHO cells and isolated mesenteric vessels without changing urinary NOx levels. High extracellular Mg2+ augmented acetylcholine-induced relaxation. SKCa and IKCa channel blockers apamin and TRAM34 inhibited Mg2+ -dependent relaxation. The endothelium-independent relaxation in aorta rings was inhibited by high extracellular Ca2+ . Combined blockade of NO, SKCa , and IKCa channels significantly reduced Mg2+ -dependent dilatation in mesenteric resistance vessels. CONCLUSIONS In mouse conductance and resistance arteries Mg2+ -induced relaxation is contributed by endothelial NO formation, EDHF pathways, antagonism of Ca2+ in smooth muscle cells, and additional unidentified mechanisms.
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Affiliation(s)
- Olga Kudryavtseva
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense C, Denmark
| | - Kristina S Lyngsø
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense C, Denmark
| | - Boye L Jensen
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense C, Denmark
| | - Henrik Dimke
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense C, Denmark
- Department of Nephrology, Odense University Hospital, Odense, Denmark
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Vasin MV. B-190 (Indralin) in Light of the History of the Formation of Ideas about the Mechanism of Action of Radioprotectors. BIOL BULL+ 2022. [DOI: 10.1134/s1062359021110091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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4
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Casey S, Herath C, Rajapaksha I, Jones R, Angus P. Effects of angiotensin-(1-7) and angiotensin II on vascular tone in human cirrhotic splanchnic vessels. Peptides 2018; 108:25-33. [PMID: 30179652 DOI: 10.1016/j.peptides.2018.08.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 08/14/2018] [Accepted: 08/14/2018] [Indexed: 12/12/2022]
Abstract
Evidence suggests that the renin angiotensin system (RAS) may play a role in the pathological splanchnic vasodilatation that leads to a hyperdynamic circulation in cirrhosis. An impaired contractile response to the angiotensin II peptide of the classical RAS system has been described in animal models of cirrhosis and in vivo in cirrhotic subjects. Furthermore, in experimental cirrhosis, the so-called alternate arm of the RAS was found to be upregulated and its effector peptide, angiotensin-(1-7) was shown to attenuate splanchnic vascular tone. The aim of this study was to explore the relevance of these findings to human disease. Omental arteries from cirrhotic and controls subjects were studied in isolation using a wire myograph. Varied protocols to evaluate the vasoactivity of RAS mediators were enacted. The contractile response to angiotensin II was comparable in cirrhotic vs control splanchnic arteries (61 ± 9 vs 68 ± 11% KPSS, respectively). Despite this, however, arterial contractility of the cirrhotic vessels correlated negatively with Child Pugh score (p = 0.0003, r=-0.83) and there was evidence that angiotensin II-induced contractility was increased in early cirrhosis. Angiotensin II-induced contractility was attenuated by angiotensin-(1-7) in cirrhotic and control arteries, however, adrenergic responses were not affected by angiotensin-(1-7). Contractile responses to angiotensin II are preserved in narrow lumen human cirrhotic splanchnic arteries and are comparatively augmented in early disease. Angiotensin-(1-7) had no vasodilatory effect on adrenergic tone, however, attenuated angiotensin II-induced contractility, possibly through an Ang-(1-7)-AT1R interaction, and thus may contribute to pathological vasodilatation in human cirrhosis.
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Affiliation(s)
- Stephen Casey
- Liver Unit, Austin Health, Melbourne, Australia; Department of Medicine, Austin Health, University of Melbourne, Australia.
| | - Chandana Herath
- Department of Medicine, Austin Health, University of Melbourne, Australia
| | - Indu Rajapaksha
- Department of Medicine, Austin Health, University of Melbourne, Australia
| | | | - Peter Angus
- Liver Unit, Austin Health, Melbourne, Australia; Department of Medicine, Austin Health, University of Melbourne, Australia
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Battault S, Meziat C, Nascimento A, Braud L, Gayrard S, Legros C, De Nardi F, Drai J, Cazorla O, Thireau J, Meyer G, Reboul C. Vascular endothelial function masks increased sympathetic vasopressor activity in rats with metabolic syndrome. Am J Physiol Heart Circ Physiol 2018; 314:H497-H507. [DOI: 10.1152/ajpheart.00217.2017] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Sylvain Battault
- Laboratoire de Pharm-Ecologie Cardiovasculaire, Avignon University, Avignon, France
| | - Cindy Meziat
- Laboratoire de Pharm-Ecologie Cardiovasculaire, Avignon University, Avignon, France
| | | | - Laura Braud
- EB2M-PROTEE, Université de Toulon, La Garde, France
| | - Sandrine Gayrard
- Laboratoire de Pharm-Ecologie Cardiovasculaire, Avignon University, Avignon, France
| | - Christian Legros
- Laboratoire de Biologie Neurovasculaire et Mitochondriale Intégrée, Université d'Angers, Angers, France
| | - Frederic De Nardi
- Laboratoire de Biologie Neurovasculaire et Mitochondriale Intégrée, Université d'Angers, Angers, France
| | - Jocelyne Drai
- Fédération de Biochimie, Unité de Biochimie Métabolique et Moléculaire, Centre Hospitalier Lyon-Sud, Pierre-Bénite, France
| | - Olivier Cazorla
- PhyMedExp, University of Montpellier, INSERM U1046, CNRS UMR 9214, Montpellier, France
| | - Jérôme Thireau
- PhyMedExp, University of Montpellier, INSERM U1046, CNRS UMR 9214, Montpellier, France
| | - Gregory Meyer
- Laboratoire de Pharm-Ecologie Cardiovasculaire, Avignon University, Avignon, France
| | - Cyril Reboul
- Laboratoire de Pharm-Ecologie Cardiovasculaire, Avignon University, Avignon, France
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Fernández-Varo G, Oró D, Cable EE, Reichenbach V, Carvajal S, de la Presa BG, Wiśniewski K, Ginés P, Harris G, Jiménez W. Vasopressin 1a receptor partial agonism increases sodium excretion and reduces portal hypertension and ascites in cirrhotic rats. Hepatology 2016; 63:207-16. [PMID: 26403564 DOI: 10.1002/hep.28250] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 09/20/2015] [Indexed: 12/30/2022]
Abstract
UNLABELLED Patients and rats with cirrhosis and ascites have portal hypertension and circulatory dysfunction. Synthetic arginine vasopressin (AVP) receptor agonists able to induce systemic and mesenteric vasoconstriction have shown their usefulness in reducing portal pressure (PP) in this condition. We assessed the potential therapeutic value of a new V1 a -AVP receptor partial agonist with a preferential splanchnic vasoconstrictor effect (FE 204038) in rats with cirrhosis and ascites. The hemodynamic effects of cumulative intravenous doses of FE 204038, terlipressin, or vehicle were investigated. Mean arterial pressure and PP were continuously recorded and cardiac output and systemic vascular resistance (SVR) assessed at 30-minute intervals for 90 minutes. Urine volume, urine osmolality, and urinary excretion of sodium and creatinine were measured in basal conditions and following twice-daily subcutaneous doses of FE 204038 or vehicle. PP, mean arterial pressure, cardiac output, SVR, and ascites volume were also measured after 6 days. The expression of an array of vasoactive genes was assessed in the thoracic aorta and the mesenteric circulation of control rats and rats with cirrhosis and ascites. FE 204038 dose-dependently decreased PP, did not modify mean arterial pressure, and increased SVR. The effect of the V1a -AVP receptor partial agonist on PP was associated with an improvement in urine volume and urinary excretion of sodium during the first day of treatment. SVR was higher and cardiac output and ascites volume were lower in rats with cirrhosis and ascites treated with FE 204038. V1a -AVP receptor expression in rats with cirrhosis and ascites was markedly enhanced in the mesenteric circulation compared to the thoracic aorta. CONCLUSION FE 204038 increases sodium excretion and reduces portal hypertension and ascites in experimental cirrhosis. V1a -AVP receptor partial agonism could be a useful pharmacological treatment in decompensated patients with cirrhosis.
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Affiliation(s)
- Guillermo Fernández-Varo
- Biochemistry and Molecular Genetics Service, Hospital Clínic i Provincial de Barcelona, IDIBAPS, CIBERehd, University of Barcelona, Barcelona, Spain.,Department Ciencies Fisiologiques I, University of Barcelona, Barcelona, Spain
| | - Denise Oró
- Biochemistry and Molecular Genetics Service, Hospital Clínic i Provincial de Barcelona, IDIBAPS, CIBERehd, University of Barcelona, Barcelona, Spain
| | | | - Vedrana Reichenbach
- Biochemistry and Molecular Genetics Service, Hospital Clínic i Provincial de Barcelona, IDIBAPS, CIBERehd, University of Barcelona, Barcelona, Spain
| | - Silvia Carvajal
- Biochemistry and Molecular Genetics Service, Hospital Clínic i Provincial de Barcelona, IDIBAPS, CIBERehd, University of Barcelona, Barcelona, Spain
| | - Bernardino González de la Presa
- Biochemistry and Molecular Genetics Service, Hospital Clínic i Provincial de Barcelona, IDIBAPS, CIBERehd, University of Barcelona, Barcelona, Spain
| | | | - Pere Ginés
- Liver Unit, Hospital Clínic i Provincial de Barcelona, IDIBAPS, CIBERehd, University of Barcelona, Barcelona, Spain
| | | | - Wladimiro Jiménez
- Biochemistry and Molecular Genetics Service, Hospital Clínic i Provincial de Barcelona, IDIBAPS, CIBERehd, University of Barcelona, Barcelona, Spain.,Department Ciencies Fisiologiques I, University of Barcelona, Barcelona, Spain
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Vasin MV, Ushakov IB, Kovtun VY, Semenova LA, Komarova SN, Galkin AA, Afanas'ev RV. Radioprotective Properties of Indralin in Combination with Monizol in the Treatment of Local Acute and Delayed Radiation Injuries Caused by Local Skin γ-Irradiation. Bull Exp Biol Med 2015; 159:747-9. [PMID: 26519270 DOI: 10.1007/s10517-015-3065-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Indexed: 11/28/2022]
Abstract
Female rats were exposed to local γ-irradiation of the right hindpaw in doses of 30-50 Gy at 131-154 sGy/min dose rate. Radioprotector indralin was administered per os 15 min prior to irradiation, monizol was injected intraperitoneally 5 min after irradiation. Indralin showed marked radioprotective properties both for acute and delayed symptoms of local radiation injuries. In combination with monizol, radioprotective effect of indralin was potentiated to dose reduction factor of 1.4-1.5 both for radiation burn severity reduction and for restriction of postradiational contracture development and amputation of the irradiated limb.
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Affiliation(s)
- M V Vasin
- State Scientific Center Institute of Medical and Biological Problems, Russian Academy of Sciences, Moscow, Russia.
| | - I B Ushakov
- State Scientific Center Institute of Medical and Biological Problems, Russian Academy of Sciences, Moscow, Russia
| | - V Yu Kovtun
- State Scientific Center Institute of Medical and Biological Problems, Russian Academy of Sciences, Moscow, Russia
| | - L A Semenova
- State Scientific Center Institute of Medical and Biological Problems, Russian Academy of Sciences, Moscow, Russia
| | - S N Komarova
- State Scientific Center Institute of Medical and Biological Problems, Russian Academy of Sciences, Moscow, Russia
| | - A A Galkin
- State Scientific Center Institute of Medical and Biological Problems, Russian Academy of Sciences, Moscow, Russia
| | - R V Afanas'ev
- State Scientific Center Institute of Medical and Biological Problems, Russian Academy of Sciences, Moscow, Russia
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8
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New insights into cirrhotic cardiomyopathy. Int J Cardiol 2013; 167:1101-8. [DOI: 10.1016/j.ijcard.2012.09.089] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 07/02/2012] [Accepted: 09/15/2012] [Indexed: 02/06/2023]
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Martell M, Coll M, Ezkurdia N, Raurell I, Genescà J. Physiopathology of splanchnic vasodilation in portal hypertension. World J Hepatol 2010; 2:208-20. [PMID: 21160999 PMCID: PMC2999290 DOI: 10.4254/wjh.v2.i6.208] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2010] [Revised: 06/09/2010] [Accepted: 06/16/2010] [Indexed: 02/06/2023] Open
Abstract
In liver cirrhosis, the circulatory hemodynamic alterations of portal hypertension significantly contribute to many of the clinical manifestations of the disease. In the physiopathology of this vascular alteration, mesenteric splanchnic vasodilation plays an essential role by initiating the hemodynamic process. Numerous studies performed in cirrhotic patients and animal models have shown that this splanchnic vasodilation is the result of an important increase in local and systemic vasodilators and the presence of a splanchnic vascular hyporesponsiveness to vasoconstrictors. Among the molecules and factors known to be potentially involved in this arterial vasodilation, nitric oxide seems to have a crucial role in the physiopathology of this vascular alteration. However, none of the wide variety of mediators can be described as solely responsible, since this phenomenon is multifactorial in origin. Moreover, angiogenesis and vascular remodeling processes also seem to play a role. Finally, the sympathetic nervous system is thought to be involved in the pathogenesis of the hyperdynamic circulation associated with portal hypertension, although the nature and extent of its role is not completely understood. In this review, we discuss the different mechanisms known to contribute to this complex phenomenon.
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Affiliation(s)
- María Martell
- María Martell, Mar Coll, Nahia Ezkurdia, Imma Raurell, Joan Genescà, Liver Diseases Laboratory, Liver Unit, Department of Internal Medicine, Hospital Universitari Vall d'Hebron, Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona 08035, Spain
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10
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Kim MY, Baik SK. [Hyperdynamic circulation in patients with liver cirrhosis and portal hypertension]. THE KOREAN JOURNAL OF GASTROENTEROLOGY = TAEHAN SOHWAGI HAKHOE CHI 2009; 54:143-8. [PMID: 19844149 DOI: 10.4166/kjg.2009.54.3.143] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Hyperdynamic circulation in patients with liver cirrhosis is characterized by increased cardiac output and heart rate, and decreased systemic vascular resistance with low arterial blood pressure and currently focused on understanding the pathogenesis because of possibility of developing novel treatment modality. Basically, these hemodynamic alternations arise from portal hypertension. Portosystemic collaterals develop to counterbalance the increased intrahepatic vascular resistance to portal blood flow and induce an increase in venous return to heart. Increased shear stress in vascular endothelial cell related high blood flow by portosystemic shunting contributes to this upregulation of eNOS resulting in NO overproduction. Additionally, bypassing through portosystemic collaterals and escaping degradation of over-produced circulating vasodilators in the diseased liver can promote the peripheral arterial vasodilation. Vasodilation of the systemic and splanchnic circulations lead to a reduced systemic vascular resistance, and increased cardiac output and splanchnic blood flow. Furthermore, neurohumoral vasoconstrictive systems including systemic nervous system, rennin angiotensin aldosterone system, and vasopressin are intensively activated secondary to vasodilation. However, hyperdynamic circulation would be more aggravated by the activated vasoconstrictive systems. With the progression of the cirrhotic process, hyperdynamic alternations can be more profound due to hyporesponsiveness to vasoconstrictors and increased shunt formation in conjunction with autonomic neuropathy. Eventually, splanchnic arterial vasodilation results in an increase portal venous inflow, maintaining the elevated portal venous pressure. Hyperdynamic circulation is intimately involved in portal hypertension with liver cirrhosis, therefore it is reasonable to have an interest in complete understanding of the pathogenesis of hyperdynamic circulation to develop novel treatment modality.
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Affiliation(s)
- Moon Young Kim
- Department of Internal Medicine, Institute of Basic Medical Science, Yonsei University Wonju College of Medicine, Wonju, Korea
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Colle I, Geerts AM, Van Steenkiste C, Van Vlierberghe H. Hemodynamic changes in splanchnic blood vessels in portal hypertension. Anat Rec (Hoboken) 2008; 291:699-713. [PMID: 18484617 DOI: 10.1002/ar.20667] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Portal hypertension (PHT) is associated with a hyperdynamic state characterized by a high cardiac output, increased total blood volume, and a decreased splanchnic vascular resistance. This splanchnic vasodilation is a result of an important increase in local and systemic vasodilators (nitric oxide, carbon monoxide, prostacyclin, endocannabinoids, and so on), the presence of a splanchnic vascular hyporesponsiveness toward vasoconstrictors, and the development of mesenteric angiogenesis. All these mechanisms will be discussed in this review. To decompress the portal circulation in PHT, portosystemic collaterals will develop. The presence of these portosystemic shunts are responsible for major complications of PHT, namely bleeding from gastrointestinal varices, encephalopathy, and sepsis. Until recently, it was accepted that the formation of collaterals was due to opening of preexisting vascular channels, however, recent data suggest also the role of vascular remodeling and angiogenesis. These points are also discussed in detail.
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Affiliation(s)
- Isabelle Colle
- Department of Hepatology and Gastroenterology, Ghent University Hospital, Ghent, Belgium.
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12
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Guo LY, Liu P. Research progress in the mechanism of renal vasoconstriction in hepatorenal syndrome. Shijie Huaren Xiaohua Zazhi 2008; 16:982-986. [DOI: 10.11569/wcjd.v16.i9.982] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Hepatorenal syndrome (HRS) is defined as the development of renal failure in patients with severe liver disease in the absence of any other identifiable cause of renal pathology. The hallmark of HRS is renal vasoconstriction. The cause of renal vasoconstriction may involve several factors: activation of renal nervous system, imbalance of renal vasoactive mediators and molecular mechanism. In this review, we summarize the above progress.
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Li J, Zhou Z, Jiang DJ, Li D, Tan B, Liu H, Li YJ. Reduction of NO- and EDHF-mediated vasodilatation in hypertension: role of asymmetric dimethylarginine. Clin Exp Hypertens 2008; 29:489-501. [PMID: 17994357 DOI: 10.1080/10641960701616194] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of nitric oxide (NO) synthase (NOS), and endothelial dysfunction is related to the elevation of ADMA level in hypertension. Besides the NO-mediated pathway, the endothelium-derived hyperpolarizing factor (EDHF)-mediated pathway is involved in endothelial dysfunction. The aims of the present study were to evaluate the changes of endothelium-dependent dilatation of arteries in hypertension and the role of ADMA in NO- and EDHF-mediated vasodilatation. The great omental arteries were isolated from essential hypertensive and normotensive patients, and mesenteric arteries were isolated from spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats. NO-, EDHF-, and prostaglandin (PGI(2))-mediated endothelium-dependent vasodilatation were measured, and plasma concentrations of ADMA were determined in rats. Cultured endothelial cells were treated with ADMA (1-10 microM) for 48 h, and the mRNA and protein level of small-conductance Ca(2+)-activated K(+) channel 3 (SK3), which has been thought to be a key mediator of EDHF, was determined. Both NO- and EDHF-mediated endothelium-dependent responses were decreased in the great omental arteries of hypertensive patients and mesenteric arteries of SHR. Plasma levels of ADMA were significantly increased in SHR. In cultured endothelial cells, the expressions of SK3 mRNA and protein were concentration-dependently down-regulated in the presence of ADMA. The present study suggests that the inhibitory effect of ADMA on endothelial function not only involves NO-mediated endothelium-dependent vasodilatation but also the EDHF-mediated pathways in hypertensive animals and humans, and that ADMA can down-regulate the expression of SK3 channels in endothelial cells.
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Affiliation(s)
- Jie Li
- Department of Pharmacology, School of Pharmaceutical Sciences, Central South University, Changsha, China
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14
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Zhou Z, Jiang DJ, Jia SJ, Xiao HB, Xiao B, Li YJ. Down-regulation of endogenous nitric oxide synthase inhibitors on endothelial SK3 expression. Vascul Pharmacol 2007; 47:265-71. [PMID: 17869187 DOI: 10.1016/j.vph.2007.08.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2007] [Revised: 05/23/2007] [Accepted: 08/02/2007] [Indexed: 12/01/2022]
Abstract
OBJECTIVES To investigate role of endogenous nitric oxide synthase inhibitor asymmetric dimethylarginine (ADMA) in down-regulation of the expression of endothelial SK3 in atherosclerosis. METHODS Apolipoprotein E deficient (apo E(-/-)) mice aged 11 approximately 12 weeks were treated with ADMA (5 mg/kg per day, subcutaneous injection) for 4 weeks. Cultured human umbilical venous endothelial cells (HUVECs) were treated with different concentrations of lysophosphatidylcholine (LPC) or ADMA for 48 h. Plasma levels of ADMA were determined by high performance liquid chromatogram (HPLC); protein and mRNA levels of SK3 in the aortas of mice and cultured cells were detected by immunofluorescence, western blot and RT-PCR, respectively. RESULTS Concomitantly with the elevated plasma levels of ADMA, the expressions of both SK3 protein and mRNA in aortas of apo E(-/-) mice were significantly reduced in comparison to those of the wild-type mice. Moreover, 4-week treatment of ADMA made levels of SK3 expression even lower. In cultured HUVECs, either LPC or ADMA notably decreased the expressions of both SK3 protein and mRNA in a concentration dependent manner. CONCLUSIONS Endogenous ADMA may be an important factor for down-regulation of the expression of endothelial SK3 in atherosclerotic animals.
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Affiliation(s)
- Zhi Zhou
- Department of Pharmacology, School of Pharmaceutical Sciences, Central South University, Changsha 410078, China
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15
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Bolognesi M, Sacerdoti D, Piva A, Di Pascoli M, Zampieri F, Quarta S, Motterlini R, Angeli P, Merkel C, Gatta A. Carbon monoxide-mediated activation of large-conductance calcium-activated potassium channels contributes to mesenteric vasodilatation in cirrhotic rats. J Pharmacol Exp Ther 2007; 321:187-94. [PMID: 17229879 DOI: 10.1124/jpet.106.116665] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Large-conductance calcium-activated potassium channels (BK(Ca)s) are important regulators of arterial tone and represent a mediator of the endogenous vasodilator carbon monoxide (CO). Because an up-regulation of the heme oxygenase (HO)/CO system has been associated with mesenteric vasodilatation of cirrhosis, we analyzed the interactions of BK(Ca) and of HO/CO in the endothelium-dependent dilatation of mesenteric arteries in ascitic cirrhotic rats. In pressurized mesenteric arteries (diameter, 170-350 microm) of ascitic cirrhotic rats, we evaluated the effect of inhibition of BK(Ca), HO, and guanylyl-cyclase on dilatation induced by acetylcholine and by exogenous CO; and HO-1 and BK(Ca) subunit protein expression. Inhibition of HO and of BK(Ca) reduced acetylcholine-induced vasodilatation more in cirrhotic rats than in control rats, whereas inhibition of guanylyl-cyclase had a similar effect in the two groups. CO was more effective in cirrhotic rats than in control rats, and the effect was hindered by BK(Ca) inhibition. The expression of HO-1 and of BK(Ca) alpha-subunit was higher in mesenteric arteries of cirrhotic rats compared with that of control animals, whereas the expression of the BK(Ca) beta1-subunit was lower. In conclusion, an overexpression of BK(Ca) alpha-subunits, possibly due to HO up-regulation with increased CO production, participates in the endothelium-dependent alterations and mesenteric arterial vasodilatation of ascitic cirrhotic rats.
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Affiliation(s)
- Massimo Bolognesi
- Department of Clinical and Experimental Medicine, University of Padova, Padova, Italy.
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Abstract
Portal hypertension is a complication of diseases that obstruct portal blood flow, such as cirrhosis or portal vein thrombosis. In these diseases, increased vascular resistance to portal blood flow is the primary mechanism that increases portal pressure. In cirrhosis, increased intrahepatic vascular resistance is a result of both intrahepatic vasoconstriction and surrounding mechanical factors including collagen deposition and regenerative nodules. This article summarizes recent progress in the understanding of molecular mechanisms underlying the portal hypertension-associated arterial alterations in splanchnic systemic territories and those involved in the development of portal-systemic collateral circulation.
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Affiliation(s)
- Richard Moreau
- INSERM, U773, Centre de Recherche Biomédicale Bichat-Beaujon CRB3, Hôpital Beaujon, Clichy 92118, France.
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Ledoux J, Werner ME, Brayden JE, Nelson MT. Calcium-activated potassium channels and the regulation of vascular tone. Physiology (Bethesda) 2006; 21:69-78. [PMID: 16443824 DOI: 10.1152/physiol.00040.2005] [Citation(s) in RCA: 320] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Different calcium signals in the endothelium and smooth muscle target different types of Ca2+-sensitive K+ channels to modulate vascular function. These differential calcium signals and targets represent multilayered opportunities for prevention and/or treatment of vascular dysfunctions.
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Affiliation(s)
- Jonathan Ledoux
- Department of Pharmacology, College of Medicine, University of Vermont, Burlington, Vermont, USA
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Wong F, Pantea L, Sniderman K. Midodrine, octreotide, albumin, and TIPS in selected patients with cirrhosis and type 1 hepatorenal syndrome. Hepatology 2004; 40:55-64. [PMID: 15239086 DOI: 10.1002/hep.20262] [Citation(s) in RCA: 220] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Hepatorenal syndrome (HRS) is a functional renal disorder complicating decompensated cirrhosis. Treatments to date, except liver transplantation, have been able to improve but not normalize renal function. The aim of this study was to determine the efficacy of transjugular intrahepatic portosystemic stent shunt (TIPS) as a treatment for type 1 HRS in ascitic cirrhotic patients, following improvement in systemic hemodynamics with a combination of midodrine, octreotide, and albumin (medical treatment). Fourteen ascitic cirrhotic patients with type 1 HRS received medical therapy until their serum creatinine reached below 135 micromol/L for at least 3 days, followed by a TIPS if there were no contraindications. Patients were assessed before and after medical treatment, as well as at 1 week and 1, 3, 6, and 12 months post-TIPS with measurements of renal function, sodium handling, systemic hemodynamics, central blood volume, and hormonal markers. Medical therapy for 14 +/- 3 days improved renal function (serum creatinine: 233 +/- 29 micromol/L vs. 112 +/- 8 micromol/L, P =.001) and renal sodium excretion (5 +/- 2 mmol/d vs. 9 +/- 2 mmol/d, P =.002) in 10 of the 14 patients. TIPS insertion in five of the responders further improved renal function and sodium excretion, so that by 12 months post-TIPS, glomerular filtration rate (96 +/- 20 mL/min, P <.01 vs. pre-TIPS) and urinary sodium excretion (119 +/- 15 mmol/d, P <.01 vs. pre-TIPS) were normal, associated with normalization of plasma renin and aldosterone levels and elimination of ascites. In conclusion, TIPS is an effective treatment for type 1 HRS in suitable patients with cirrhosis and ascites, following the improvement of renal function with combination therapy of midodrine, octreotide, and albumin.
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Affiliation(s)
- Florence Wong
- Division of Gastroenterology, Department of Medicine, Toronto General Hospital, University of Toronto, Toronto, Ontario, Canada.
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Crane GJ, Gallagher N, Dora KA, Garland CJ. Small- and intermediate-conductance calcium-activated K+ channels provide different facets of endothelium-dependent hyperpolarization in rat mesenteric artery. J Physiol 2003; 553:183-9. [PMID: 14555724 PMCID: PMC2343487 DOI: 10.1113/jphysiol.2003.051896] [Citation(s) in RCA: 148] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Activation of both small-conductance (SKCa) and intermediate-conductance (IKCa) Ca2+-activated K+ channels in endothelial cells leads to vascular smooth muscle hyperpolarization and relaxation in rat mesenteric arteries. The contribution that each endothelial K+ channel type makes to the smooth muscle hyperpolarization is unknown. In the presence of a nitric oxide (NO) synthase inhibitor, ACh evoked endothelium and concentration-dependent smooth muscle hyperpolarization, increasing the resting potential (approx. -53 mV) by around 20 mV at 3 microM. Similar hyperpolarization was evoked with cyclopiazonic acid (10 microM, an inhibitor of sarcoplasmic endoplasmic reticulum calcium ATPase (SERCA)) while 1-EBIO (300 microM, an IKCa activator) only increased the potential by a few millivolts. Hyperpolarization in response to either ACh or CPA was abolished with apamin (50 nM, an SKCa blocker) but was unaltered by 1-[(2-chlorophenyl) diphenylmethyl]-1H-pyrazole (1 microM TRAM-34, an IKCa blocker). During depolarization and contraction in response to phenylephrine (PE), ACh still increased the membrane potential to around -70 mV, but with apamin present the membrane potential only increased just beyond the original resting potential (circa -58 mV). TRAM-34 alone did not affect hyperpolarization to ACh but, in combination with apamin, ACh-evoked hyperpolarization was completely abolished. These data suggest that true endothelium-dependent hyperpolarization of smooth muscle cells in response to ACh is attributable to SKCa channels, whereas IKCa channels play an important role during the ACh-mediated repolarization phase only observed following depolarization.
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Affiliation(s)
- G J Crane
- Department of Pharmacy and Pharmacology, University of Bath, Bath BA2 7AY, UK
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Taylor MS, Bonev AD, Gross TP, Eckman DM, Brayden JE, Bond CT, Adelman JP, Nelson MT. Altered expression of small-conductance Ca2+-activated K+ (SK3) channels modulates arterial tone and blood pressure. Circ Res 2003; 93:124-31. [PMID: 12805243 DOI: 10.1161/01.res.0000081980.63146.69] [Citation(s) in RCA: 227] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The endothelium is a critical regulator of vascular tone, and dysfunction of the endothelium contributes to numerous cardiovascular pathologies. Recent studies suggest that apamin-sensitive, small-conductance, Ca2+-activated K+ channels may play an important role in active endothelium-dependent vasodilations, and expression of these channels may be altered in disease states characterized by vascular dysfunction. Here, we used a transgenic mouse (SK3T/T) in which SK3 expression levels can be manipulated with dietary doxycycline (DOX) to test the hypothesis that the level of expression of the SK subunit, SK3, in endothelial cells alters arterial function and blood pressure. SK3 protein was elevated in small mesenteric arteries from SK3T/T mice compared with wild-type mice and was greatly suppressed by dietary DOX. SK3 was detected in the endothelium and not in the smooth muscle by immunohistochemistry. In whole-cell patch-clamp experiments, SK currents in endothelial cells from SK3T/T mice were almost completely suppressed by dietary DOX. In intact arteries, SK3 channels contributed to sustained hyperpolarization of the endothelial membrane potential, which was communicated to the arterial smooth muscle. Pressure- and phenylephrine-induced constrictions of SK3T/T arteries were substantially enhanced by treatment with apamin, suppression of SK3 expression with DOX, or removal of the endothelium. In addition, suppression of SK3 expression caused a pronounced and reversible elevation of blood pressure. These results indicate that endothelial SK3 channels exert a profound, tonic, hyperpolarizing influence in resistance arteries and suggest that the level of SK3 channel expression in endothelial cells is a fundamental determinant of vascular tone and blood pressure.
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Affiliation(s)
- Mark S Taylor
- Department of Pharmacology, University of Vermont, 89 Beaumont Ave, Burlington, VT 05405, USA
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Moreau R, Barrière E, Tazi KA, Lardeux B, Dargère D, Urbanowicz W, Poirel O, Chauvelot-Moachon L, Guimont MC, Bernuau D, Lebrec D. Terlipressin inhibits in vivo aortic iNOS expression induced by lipopolysaccharide in rats with biliary cirrhosis. Hepatology 2002; 36:1070-8. [PMID: 12395316 DOI: 10.1053/jhep.2002.36501] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
In cirrhosis, lipopolysaccharide (LPS, a product of Gram-negative bacteria) in the blood may cause septic shock. LPS-elicited induction of arterial inducible nitric oxide synthase (iNOS) results in nitric oxide (NO)-induced vasodilation, which causes arterial hypotension and hyporeactivity to alpha(1)-adrenergic constrictors. In vitro studies have suggested that vasopressin inhibits iNOS expression in cultured vascular smooth muscle cells exposed to LPS. Thus, the aim of this study was to investigate the effects of terlipressin administration (a vasopressin analog) on in vivo LPS-induced aortic iNOS in rats with cirrhosis. LPS (1 mg/kg, intravenously) was administered followed by the intravenous administration of terlipressin (0.05 mg/kg, intravenously) or placebo 1 hour later. Arterial pressure was measured, and contractions to phenylephrine (an alpha(1)-adrenoceptor agonist), iNOS activity, and iNOS expressions (mRNA and protein) were investigated in isolated aortas. LPS-induced arterial hypotension and aortic hyporeactivity to phenylephrine were abolished in rats that received terlipressin. LPS-induced aortic iNOS activity and expression were suppressed in terlipressin-treated rats. In conclusion, in LPS-challenged rats with cirrhosis, terlipressin administration inhibits in vivo LPS-induced aortic iNOS expression. Terlipressin administration may be a novel approach for the treatment of arterial hypotension and hyporeactivity to alpha(1)-adrenergic constrictors in patients with cirrhosis and septic shock.
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Affiliation(s)
- Richard Moreau
- Laboratoire d'Hémodynamique Splanchnique et de Biologie Vasculaire, INSERM U-481, Hôpital Beaujon, Paris, France.
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