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Cho TJ, Kim HJ, Cho J. Endothelin-converting enzyme-1 expression in acute and chronic liver injury in fibrogenesis. Anim Cells Syst (Seoul) 2019; 23:170-175. [PMID: 31231580 PMCID: PMC6566842 DOI: 10.1080/19768354.2019.1595141] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 02/22/2019] [Accepted: 03/07/2019] [Indexed: 12/31/2022] Open
Abstract
Endothelin-1 (ET-1) induces contraction, proliferation, and collagen synthesis of activated hepatic stellate cells and is a potent mediator of portal hypertension. Endothelin-converting enzyme-1 (ECE-1) generates ET-1 from the inactive precursor big-endothelin-1. The cellular distribution and activity of ECE-1 in the liver is unknown. Hepatic fibrogenesis was induced in rats by CCl4 administration and secondary biliary cirrhosis after 6 weeks of complete bile duct occlusion (BDO). The tissue ET-1 and ET receptor protein levels were quantified, the ECE-1 isoform mRNAs were measured by RNase protection assay and ECE-1 activity was analyzed. ECE-1a and -b mRNA were upregulated in biliary cirrhosis and in CCl4-injured livers, whereas ECE-1c mRNA remained unchanged. ECE-1 activity was increased after BDO and peaked at 12 h after acute CCl4-intoxication. Tissue levels of ET-1, ETA- and ETB receptors were elevated 7-, 5-, and 4.6-fold in cirrhotic rats, respectively. ECE-1 activity increased following BDO and acute CCl4-intoxication. In conclusion, ECE-1a and -b RNAs are upregulated in fibrogenesis, indicating that these isoforms play a central role in ET-1 generation during fibrogenesis and portal hypertension.
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Affiliation(s)
- Tae-Jun Cho
- Labratory of Developmental Biology and Stem Cell Differentiation/Transplantation, Department of Dental Regenerative Biotechnology, School of Dentistry, Seoul National University South Korea, Seoul, South Korea.,Dental Research Institute, Seoul National University, Seoul, South Korea
| | - Hyo-Jung Kim
- Dental Research Institute, Seoul National University, Seoul, South Korea
| | - Jaejin Cho
- Labratory of Developmental Biology and Stem Cell Differentiation/Transplantation, Department of Dental Regenerative Biotechnology, School of Dentistry, Seoul National University South Korea, Seoul, South Korea.,Dental Research Institute, Seoul National University, Seoul, South Korea
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2
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Chan EAW, Buckley B, Farraj AK, Thompson LC. The heart as an extravascular target of endothelin-1 in particulate matter-induced cardiac dysfunction. Pharmacol Ther 2016; 165:63-78. [PMID: 27222357 PMCID: PMC6390286 DOI: 10.1016/j.pharmthera.2016.05.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Exposure to particulate matter air pollution has been causally linked to cardiovascular disease in humans. Several broad and overlapping hypotheses describing the biological mechanisms by which particulate matter exposure leads to cardiovascular disease have been explored, although linkage with specific factors or genes remains limited. These hypotheses may or may not also lead to particulate matter-induced cardiac dysfunction. Evidence pointing to autocrine/paracrine signaling systems as modulators of cardiac dysfunction has increased interest in the emerging role of endothelins as mediators of cardiac function following particulate matter exposure. Endothelin-1, a well-described small peptide expressed in the pulmonary and cardiovascular systems, is best known for its ability to constrict blood vessels, although it can also induce extravascular effects. Research on the role of endothelins in the context of air pollution has largely focused on vascular effects, with limited investigation of responses resulting from the direct effects of endothelins on cardiac tissue. This represents a significant knowledge gap in air pollution health effects research, given the abundance of endothelin receptors found on cardiac tissue and the ability of endothelin-1 to modulate cardiac contractility, heart rate, and rhythm. The plausibility of endothelin-1 as a mediator of particulate matter-induced cardiac dysfunction is further supported by the therapeutic utility of certain endothelin receptor antagonists. The present review examines the possibility that endothelin-1 release caused by exposure to PM directly modulates extravascular effects on the heart, deleteriously altering cardiac function.
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Affiliation(s)
- Elizabeth A W Chan
- Oak Ridge Institute for Science and Education (ORISE) Fellow at the National Center for Environmental Assessment, U.S. Environmental Protection Agency (EPA), Research Triangle Park, NC, USA
| | - Barbara Buckley
- National Center for Environmental Assessment, U.S. EPA, Research Triangle Park, NC, USA
| | - Aimen K Farraj
- Environmental Public Health Division, U.S. EPA, Research Triangle Park, NC, USA
| | - Leslie C Thompson
- Environmental Public Health Division, U.S. EPA, Research Triangle Park, NC, USA.
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Modulation by endothelin-1 of spontaneous activity and membrane currents of atrioventricular node myocytes from the rabbit heart. PLoS One 2012; 7:e33448. [PMID: 22479400 PMCID: PMC3315568 DOI: 10.1371/journal.pone.0033448] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Accepted: 02/10/2012] [Indexed: 11/19/2022] Open
Abstract
Background The atrioventricular node (AVN) is a key component of the cardiac pacemaker-conduction system. Although it is known that receptors for the peptide hormone endothelin-1 (ET-1) are expressed in the AVN, there is very little information available on the modulatory effects of ET-1 on AVN electrophysiology. This study characterises for the first time acute modulatory effects of ET-1 on AVN cellular electrophysiology. Methods Electrophysiological experiments were conducted in which recordings were made from rabbit isolated AVN cells at 35–37°C using the whole-cell patch clamp recording technique. Results Application of ET-1 (10 nM) to spontaneously active AVN cells led rapidly (within ∼13 s) to membrane potential hyperpolarisation and cessation of spontaneous action potentials (APs). This effect was prevented by pre-application of the ETA receptor inhibitor BQ-123 (1 µM) and was not mimicked by the ETB receptor agonist IRL-1620 (300 nM). In whole-cell voltage-clamp experiments, ET-1 partially inhibited L-type calcium current (ICa,L) and rapid delayed rectifier K+ current (IKr), whilst it transiently activated the hyperpolarisation-activated current (If) at voltages negative to the pacemaking range, and activated an inwardly rectifying current that was inhibited by both tertiapin-Q (300 nM) and Ba2+ ions (2 mM); each of these effects was sensitive to ETA receptor inhibition. In cells exposed to tertiapin-Q, ET-1 application did not produce membrane potential hyperpolarisation or immediate cessation of spontaneous activity; instead, there was a progressive decline in AP amplitude and depolarisation of maximum diastolic potential. Conclusions Acutely applied ET-1 exerts a direct modulatory effect on AVN cell electrophysiology. The dominant effect of ET-1 in this study was activation of a tertiapin-Q sensitive inwardly rectifying K+ current via ETA receptors, which led rapidly to cell quiescence.
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4
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Reel B, Ozkal S, Islekel H, Ozer E, Oktay G, Sozer GO, Tanriverdi S, Turkseven S, Kerry Z. The role of endothelin receptor antagonism in collar-induced intimal thickening and vascular reactivity changes in rabbits. J Pharm Pharmacol 2010; 57:1599-608. [PMID: 16354404 DOI: 10.1211/jpp.57.12.0010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Abstract
Intimal thickening, due to smooth muscle cell migration and proliferation, is considered to be one of the major components of vascular proliferative disorders such as atherosclerosis and restenosis. One experimental model, resulting in intimal thickening in the rabbit, involves placing a silicon collar around the carotid artery, and is used in this study. Endothelin is known to act as a strong mitogen and to stimulate smooth muscle cell proliferation and migration. We investigated the contribution of endothelin to the development of collar-induced intimal thickening and the effects of TAK-044, (5mg kg−1 daily, s.c.), a non-selective ETA/ETB receptor antagonist, on intimal thickening and vascular reactivity changes in the collared rabbit carotid artery. Endothelin levels and the intimal cross-sectional area, as well as the ratio of intimal area to media (index), increased significantly in collared arteries as compared with those in sham-operated arteries. TAK-044 significantly inhibited intimal thickening and also decreased the index without affecting increased endothelin levels in collared arteries. Vascular reactivity changes in response to collaring produced predictable effects, such as decreased contractile responses to vasoconstrictor agents and increased sensitivity to serotonin (5-hydroxytrypt-amine, 5-HT). In terms of contractile responses in this model, TAK-044, in particular, did not affect collar-induced vascular reactivity changes. These results suggest that endothelin may be involved in the pathogenesis of collar-induced intimal thickening. As an endothelin receptor antagonist, TAK-044 may potentially be beneficial in the treatment of atherosclerosis.
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Affiliation(s)
- Buket Reel
- Ege University, Faculty of Pharmacy, Department of Pharmacology, Bornova, Izmir, Turkey
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5
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Reel B, Oktay G, Ozkal S, Islekel H, Ozer E, Ozsarlak-Sozer G, Cavdar Z, Akhisaroglu ST, Kerry Z. MMP-2 and MMP-9 Alteration in Response to Collaring in Rabbits: The Effects of Endothelin Receptor Antagonism. J Cardiovasc Pharmacol Ther 2009; 14:292-301. [DOI: 10.1177/1074248409343690] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Matrix metalloproteinases (MMPs), and, in particular, gelatinases (MMP-2 and MMP-9), have been implicated in vascular cell proliferation and/or migration, contributing to intimal thickening, an essential stage in the development of atherosclerosis and restenosis following balloon angioplasty. Endothelin, a strong chemoatractant and mitogen, has been shown to promote smooth muscle cell proliferation and migration by activating MMPs via endothelin-A (ETA) receptors. The positioning of a soft silicon collar around the left carotid artery in rabbits results in intimal thickening. In this study, we investigate the possible role of gelatinases and the effect of a nonselective ETA/ETB receptor antagonist, TAK-044 (5 mg/kg body weight/day, subcutaneously [sc]), on these enzymes. Our results demonstrated that both MMP-2 and MMP-9 activities increased in response to collaring in placebo group, while treatment with TAK-044 significantly suppressed both gelatinase activities and proMMP-2 levels, and inhibited intimal thickening in collared arteries. These results suggest that either enhanced MMP expression or endothelin receptor antagonism may be involved in the formation of intimal thickening in this model.
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Affiliation(s)
- Buket Reel
- Department of Pharmacology, Faculty of Pharmacy, Ege University, Bornova, Izmir, Turkey
| | - Gulgun Oktay
- Department of Biochemistry, Ege University, Bornova, Izmir, Turkey
| | - Sermin Ozkal
- Department of Pathology, School of Medicine, Dokuz Eylul University, Inciralti, Izmir, Turkey
| | - Huray Islekel
- Department of Biochemistry, Ege University, Bornova, Izmir, Turkey
| | - Erdener Ozer
- Department of Pathology, School of Medicine, Dokuz Eylul University, Inciralti, Izmir, Turkey
| | - Gonen Ozsarlak-Sozer
- Department of Pharmacology, Faculty of Pharmacy, Ege University, Bornova, Izmir, Turkey
| | - Zahide Cavdar
- Department of Biochemistry, Ege University, Bornova, Izmir, Turkey
| | | | - Zeliha Kerry
- Department of Pharmacology, Faculty of Pharmacy, Ege University, Bornova, Izmir, Turkey,
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Martínez-Miguel P, Raoch V, Zaragoza C, Valdivielso JM, Rodríguez-Puyol M, Rodríguez-Puyol D, López-Ongil S. Endothelin-converting enzyme-1 increases in atherosclerotic mice: potential role of oxidized low density lipoproteins. J Lipid Res 2009; 50:364-375. [DOI: 10.1194/jlr.m800215-jlr200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Abstract
Endothelins are powerful vasoconstrictor peptides that also play numerous other roles. The endothelin (ET) family consists of three peptides produced by a variety of tissues. Endothelin-1 (ET-1) is the principal isoform produced by the endothelium in the human cardiovascular system, and it exerts its actions through binding to specific receptors, the so-called type A (ET(A)) and type B (ET(B)) receptors. ET-1 is primarily a locally acting paracrine substance that appears to contribute to the maintenance of basal vascular tone. It is also activated in several diseases, including congestive heart failure, arterial hypertension, atherosclerosis, endothelial dysfunction, coronary artery diseases, renal failure, cerebrovascular disease, pulmonary arterial hypertension, and sepsis. Thus, ET-1 antagonists are promising new agents. They have been shown to be effective in the management of primary pulmonary hypertension, but disappointing in heart failure. Clinical trials are needed to determine whether manipulation of the ET system will be beneficial in other diseases.
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Affiliation(s)
- Rahman Shah
- Section of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA
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Mitani H, Kimura M. Fluvastatin, HMG-CoA Reductase Inhibitor: Antiatherogenic Profiles Through Its Lipid-Lowering-Dependent and -Independent Actions. ACTA ACUST UNITED AC 2006. [DOI: 10.1111/j.1527-3466.2000.tb00053.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Taylor AJ, Al-Saadi N, Abdel-Aty H, Schulz-Menger J, Messroghli DR, Gross M, Dietz R, Friedrich MG. Elective percutaneous coronary intervention immediately impairs resting microvascular perfusion assessed by cardiac magnetic resonance imaging. Am Heart J 2006; 151:891.e1-7. [PMID: 16569557 DOI: 10.1016/j.ahj.2005.09.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2005] [Accepted: 09/21/2005] [Indexed: 10/24/2022]
Abstract
BACKGROUND Percutaneous coronary intervention (PCI) is known to induce atherosclerotic plaque rupture, which may affect resting distal microvascular perfusion either through distal microvascular spasm or through embolization. We evaluated the effect of PCI on resting microvascular flow. METHODS We performed cardiovascular magnetic resonance imaging to assess left ventricular systolic function and microvascular perfusion in 15 patients with stable coronary artery disease before and within 24 hours after PCI and in 10 control subjects without obstructive coronary artery disease on a clinical 1.5-T CMR scanner. Microvascular perfusion was evaluated at rest after injecting a bolus of gadolinium-diethylenetriamine pentaacetic acid (0.1 mmol/kg) by calculating the time to 50% maximum myocardial enhancement (T50% max), as well as the relative upslope, of the myocardial signal intensity curve. Regional perfusion and systolic thickening were evaluated using a 16-segment left ventricular model with the slice locations matched anatomically pre-PCI and post-PCI. The relative contrast delay in the region of myocardium subtended by the PCI artery was calculated by subtracting the T50% max of a remote region from the PCI region. RESULTS In subjects with coronary artery disease, PCI resulted in a regional contrast delay (mean delay 0.6 +/- 0.2 seconds post-PCI vs 0.0 +/- 0.2 seconds pre-PCI, P < .05) and a reduction in the relative upslope (8.6 +/- 0.5 post-PCI vs 10.1 +/- 0.7 pre-PCI, P = .02), consistent with reduced microvascular perfusion. This was unaccompanied by any change in regional systolic thickening (54% +/- 7% pre-PCI vs 53% +/- 5% post-PCI, P = NS). CONCLUSIONS The data show PCI-induced impairment of resting microvascular perfusion in the area of myocardium subtended by the treated artery after PCI, a likely consequence of iatrogenic atherosclerotic plaque rupture.
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10
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Lee TM, Lin MS, Chou TF, Chang NC. Effect of simvastatin on left ventricular mass in hypercholesterolemic rabbits. Am J Physiol Heart Circ Physiol 2004; 288:H1352-8. [PMID: 15486036 DOI: 10.1152/ajpheart.00527.2003] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Epidemiological studies showed that hypercholesterolemia is associated with higher left ventricular mass. Endothelin signaling is activated in hyperlipidemic animals and may contribute to progressive ventricular hypertrophy. Simvastatin has been shown to inhibit endothelin-1. However, the behavior of simvastatin on ventricular hypertrophy in hyperlipidemic animals is not well understood. In this study, we evaluated the hemodynamic, biochemical, and morphological responses to simvastatin in cholesterol-fed (1%) rabbits. The left ventricular weight increased 8 wk after cholesterol feeding compared with that in normocholesterolemic rabbits. Simvastatin at a clinical therapeutic dose (1.2 mg x kg(-1) x day(-1)) significantly decreased left ventricular weight by 14% and left ventricular myocyte sizes by 14% as isolated by enzymatic dissociation. Hypercholesterolemia upregulated ventricular preproendothelin-1 mRNA as assessed by real-time quantitative RT-PCR and elevated production of cardiac endothelin-1 concentration. The increased endothelin-1 responses can be inhibited after simvastatin administration. Left ventricular mass indexed by body weight positively correlated with tissue endothelin-1 levels (P = 0.0003). In Langendorff-perfused rabbit hearts, hyperlipidemia led to significant QT prolongation compared with normocholesterolemia, which can be reversed by administering simvastatin. In contrast, simvastatin-induced beneficial effects were reversed by the addition of mevalonate. The addition of bosentan, a nonspecific endothelin receptor blocker, improved the response in hypercholesterolemic rabbits and did not have additional beneficial effects in simvastatin-treated rabbits. The results of the present study suggest that the antihypertropic and electrocardiographic effects of simvastatin at a clinical therapeutic dose are mediated through inhibition of tissue endothelin-1 expression, which is linked to mevalonate metabolism, and result in an amelioration of cardiomyocyte hypertrophy development by an atherogenic diet.
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Affiliation(s)
- Tsung-Ming Lee
- Cardiology Section, Department of Internal Medicine, Taipei Medical University and Chi-Mei Medical Center, Tainan, Taiwan
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11
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Taylor AJ, Bobik A, Richards M, Kaye D, Raines G, Gould P, Jennings G. Myocardial endothelin-1 release and indices of inflammation during angioplasty for acute myocardial infarction and stable coronary artery disease. Am Heart J 2004; 148:e10. [PMID: 15309013 DOI: 10.1016/j.ahj.2004.03.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Elevations in endothelin-1 (ET-1) and inflammatory cytokines may impair myocardial reperfusion through the induction of microvascular constriction or obstruction; however, the generation of these factors close to the site of lesion rupture is unknown. METHODS AND RESULTS Coronary sinus (CS) and aortic blood was sampled during angioplasty for acute myocardial infarction (AMI) or stable angina to assess the local release of ET-1, interleukin-1beta, interleukin-6, tumor necrosis factor-alpha and C-reactive protein following atherosclerotic plaque rupture. Transthoracic echocardiography documented left ventricular function in AMI. ET-1 levels were higher in CS than in aortic blood in AMI (3.0 +/- 0.3 pmol/L vs 2.6 +/- 0.3 pmol/L, P =.04), but not in stable angina (1.7 +/- 0.2 pmol/L vs 1.5 +/- 0.3 pmol/L, P = NS). CS ET-1 levels were also higher in AMI than in stable angina (3.0 +/- 0.3 pmol/L vs 1.7 +/- 0.2 pmol/L, P =.002), and correlated with left ventricular dysfunction (R(2) = 0.51, P =.02). In contrast, C-reactive protein levels were higher in CS than in aortic blood only in stable angina (2.3 +/- 0.4 mg/L vs 1.8 +/- 0.3 mg/L, P =.01). Similarly, CS tumor necrosis factor-alpha was higher in stable angina than in AMI (6.0 +/- 1.4 pg/mL vs 2.5 +/- 0.9 pg/mL, P =.02). CONCLUSIONS Local myocardial release of ET-1 is highest in AMI, where it relates to the extent of myocardial dysfunction. Although local inflammation is a component of stable coronary artery disease, it does not appear acutely enhanced in AMI.
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Affiliation(s)
- Andrew J Taylor
- Baker Medical Research Institute and Alfred and Baker Medical Unit, Heart Centre, Alfred Hospital, Melbourne, Australia.
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12
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Abstract
The endothelin (ET) system is comprised of 4 active ETs, with ET-1 being the predominant isoform in the cardiovascular system. Because of the potent vasoconstricting and mitogenic effects of ET-1 and its involvement in various cardiovascular diseases, blockade of the ET receptor has received considerable attention. ET receptor antagonism has been demonstrated to be beneficial in patients with pulmonary hypertension. The nonselective ET receptor antagonist bosentan improves exercise capacity and increases time to clinical worsening in patients with pulmonary arterial hypertension. The selective ET A receptor antagonist sitaxsentan also improves hemodynamics and exercise capacity in patients with pulmonary arterial hypertension. Results with ET receptor antagonists in congestive heart failure have been disappointing. Although some studies have suggested benefit, larger studies have been neutral. The use of ET receptor antagonists for other conditions has not been fully explored. Future studies with the use of ET receptor antagonists as part of a multidrug regimen are also needed.
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Affiliation(s)
- Stuart Rich
- Rush Heart Institute Center for Pulmonary Heart Disease, Rush Medical College, Chicago, Ill, USA.
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13
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Wronski T, Seeliger E, Persson PB, Harnath A, Flemming B. Influence of baroreflex on volume elasticity of heart and aorta in the rabbit. Am J Physiol Regul Integr Comp Physiol 2002; 282:R842-9. [PMID: 11832406 DOI: 10.1152/ajpregu.00474.2001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Optimal ventriculoaortic coupling includes tuning of elastic properties. The ratio of effective arterial elastance and left ventricular endsystolic elastance is often taken as a measure for mechanical and energetical efficiency. The present study determined the time course of ventricular and aortic volume elasticity (VE = dp/dV) throughout a complete heartbeat. This was achieved by using changes of eigenfrequency of two catheter-transducer systems under closed chest conditions in rabbits. Short-term VE modulation was studied by a baroreflex response, as induced by pressure changes applied to the carotid sinus. Long-term changes were studied in atherosclerotic rabbits (12 wk of high-cholesterol feeding). The time course and mean values of ventricular and aortic VE were changed by the baroreflex stimulus. Cholesterol feeding diminished the response. The degree of ventriculoaortic coupling, as quantified by VE(Aorta)/VE(Ventricle) ratio, varied during a single ejection period. The large span allows either maximal energetical efficiency or maximal stroke work. Although normal rabbits adjusted their ventriculoaortic coupling during baroreflex input, the cholesterol-fed rabbits failed to do so.
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Affiliation(s)
- T Wronski
- Johannes-Müller-Institut für Physiologie, Humboldt Universität (Charité), D-10117 Berlin, Germany.
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14
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Taylor AJ, Bobik A, Berndt MC, Ramsay D, Jennings G. Experimental rupture of atherosclerotic lesions increases distal vascular resistance: a limiting factor to the success of infarct angioplasty. Arterioscler Thromb Vasc Biol 2002; 22:153-60. [PMID: 11788476 DOI: 10.1161/hq0102.101128] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Rupture of atherosclerotic lesions, resulting in localized thrombi and marked falls in distal blood flow, is a pivotal event in unstable coronary syndromes. We tested the hypothesis that after lesion rupture, vasoconstrictor mechanisms are major contributors to a marked rise in distal microvascular resistance, which is responsible for much of the interruption in blood flow. Cholesterol-fed rabbits underwent endothelial denudation of their left iliac arteries to induce angiographically severe, fatty, American Heart Association type IV-like atherosclerotic lesions. After lesion disruption with a stiff wire, we measured distal blood flow and pressure, capillary patency in the distal vascular bed, and the response to the vasodilators adenosine, nitroprusside, and glyceryl trinitrate. Morphology of the lesions and of the associated thrombi was also examined to assess lumen restriction at the site of rupture. Disruption of atherosclerotic lesions reduced mean flow from 5.04+/-1.21 to 1.23+/-0.37 mL/min (P<0.005), and calculated distal vascular resistance rose rapidly, from 17.5+/-2.9 to 37.9+/-6.4 mm Hg. min/mL (P<0.005). Lesion rupture did not significantly affect capillary patency in the distal muscle vascular bed, and although nonocclusive thrombi were present at the site of nearly all ruptured lesions, embolized thrombi were rare in capillaries (<1%). The early rise in distal microvascular resistance could be normalized with intra-arterially administered adenosine or the NO donor nitroprusside, but not glyceryl trinitrate, an organonitrate possessing large muscular artery-selective vasodilator characteristics. Thus, rupture of atherosclerotic lesions induces rapid and marked increases in distal vascular resistance, which is the consequence of severe microvascular vasoconstriction. Therapeutic targeting of the microvasculature should improve reperfusion in acute coronary syndromes.
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Affiliation(s)
- Andrew J Taylor
- Baker Medical Research Institute and Alfred and Baker Medical Unit, Heart Centre, Alfred Hospital, Melbourne, Australia.
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15
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Abstract
The role of the endothelium in the control of coronary flow has been demonstrated. Results of recent studies, both on animals and on humans, suggest that endogenous endothelin also plays an important role in basal coronary tone. Disease processes such as ischaemia-reperfusion injury, congestive heart failure, hypertension and atherosclerosis may be contributed to by an imbalance in, or excess of, release of endothelin. With the discovery of newer endothelin antagonists and endothelin converting enzyme inhibitors, especially with fewer hepatic side effects, there is the potential for much future research into novel therapeutic management of these common cardiovascular disorders.
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Affiliation(s)
- A T Goodwin
- Department of Cardiac Surgery, Papworth Hospital NHS Trust, Papworth Everard, Cambridge, UK.
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16
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Abstract
The endothelin system consists of two G-protein-coupled receptors, three peptide ligands, and two activating peptidases. Its pharmacological complexity is reflected by the diverse expression pattern of endothelin system components, which have a variety of physiological and pathophysiological roles. In the vessels, the endothelin system has a basal vasoconstricting role and participates in the development of diseases such as hypertension, atherosclerosis, and vasospasm after subarachnoid hemorrhage. In the heart, the endothelin system affects inotropy and chronotropy, and it mediates cardiac hypertrophy and remodeling in congestive heart failure. In the lungs, the endothelin system regulates the tone of airways and blood vessels, and it is involved in the development of pulmonary hypertension. In the kidney, it controls water and sodium excretion and acid-base balance, and it participates in acute and chronic renal failure. In the brain, the endothelin system modulates cardiorespiratory centers and the release of hormones. More advanced functional analysis of the endothelin system awaits not only additional pharmacological studies using highly specific endothelin antagonists but also the generation of genetically altered rodent models with conditional loss-of-function and gain-of-function manipulations.
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Affiliation(s)
- R M Kedzierski
- Department of Molecular Genetics University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390-9050, USA.
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