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Kiyooka T, Ohanyan V, Yin L, Pung YF, Chen YR, Chen CL, Kang PT, Hardwick JP, Yun J, Janota D, Peng J, Kolz C, Guarini G, Wilson G, Shokolenko I, Stevens DA, Chilian WM. Mitochondrial DNA integrity and function are critical for endothelium-dependent vasodilation in rats with metabolic syndrome. Basic Res Cardiol 2022; 117:3. [PMID: 35039940 PMCID: PMC9030679 DOI: 10.1007/s00395-021-00908-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 12/21/2021] [Accepted: 12/22/2021] [Indexed: 01/31/2023]
Abstract
Endothelial dysfunction in diabetes is generally attributed to oxidative stress, but this view is challenged by observations showing antioxidants do not eliminate diabetic vasculopathy. As an alternative to oxidative stress-induced dysfunction, we interrogated if impaired mitochondrial function in endothelial cells is central to endothelial dysfunction in the metabolic syndrome. We observed reduced coronary arteriolar vasodilation to the endothelium-dependent dilator, acetylcholine (Ach), in Zucker Obese Fatty rats (ZOF, 34 ± 15% [mean ± standard deviation] 10-3 M) compared to Zucker Lean rats (ZLN, 98 ± 11%). This reduction in dilation occurred concomitantly with mitochondrial DNA (mtDNA) strand lesions and reduced mitochondrial complex activities in the endothelium of ZOF versus ZLN. To demonstrate endothelial dysfunction is linked to impaired mitochondrial function, administration of a cell-permeable, mitochondria-directed endonuclease (mt-tat-EndoIII), to repair oxidatively modified DNA in ZOF, restored mitochondrial function and vasodilation to Ach (94 ± 13%). Conversely, administration of a cell-permeable, mitochondria-directed exonuclease (mt-tat-ExoIII) produced mtDNA strand breaks in ZLN, reduced mitochondrial complex activities and vasodilation to Ach in ZLN (42 ± 16%). To demonstrate that mitochondrial function is central to endothelium-dependent vasodilation, we introduced (via electroporation) liver mitochondria (from ZLN) into the endothelium of a mesenteric vessel from ZOF and restored endothelium-dependent dilation to vasoactive intestinal peptide (VIP at 10-5 M, 4 ± 3% vasodilation before mitochondrial transfer and 48 ± 36% after transfer). Finally, to demonstrate mitochondrial function is key to endothelium-dependent dilation, we administered oligomycin (mitochondrial ATP synthase inhibitor) and observed a reduction in endothelium-dependent dilation. We conclude that mitochondrial function is critical for endothelium-dependent vasodilation.
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Affiliation(s)
- Takahiko Kiyooka
- Division of Cardiology, Tokai University Oiso Hospital, Kanagawa Japan
| | - Vahagn Ohanyan
- Department of Integrative Medical Sciences, Northeast Ohio Medical University
| | - Liya Yin
- Department of Integrative Medical Sciences, Northeast Ohio Medical University
| | - Yuh Fen Pung
- Division of Biomedical Sciences, University of Nottingham, Malaysia Campus
| | - Yeong-Renn Chen
- Department of Integrative Medical Sciences, Northeast Ohio Medical University
| | - Chwen-Lih Chen
- Department of Integrative Medical Sciences, Northeast Ohio Medical University
| | - Patrick T. Kang
- Department of Integrative Medical Sciences, Northeast Ohio Medical University
| | - James P. Hardwick
- Department of Integrative Medical Sciences, Northeast Ohio Medical University
| | - June Yun
- Department of Integrative Medical Sciences, Northeast Ohio Medical University
| | - Danielle Janota
- Department of Integrative Medical Sciences, Northeast Ohio Medical University
| | - Joanna Peng
- Department of Integrative Medical Sciences, Northeast Ohio Medical University
| | - Christopher Kolz
- Department of Integrative Medical Sciences, Northeast Ohio Medical University
| | | | - Glenn Wilson
- Department of Biomedical Science, University of South Alabama
| | - Inna Shokolenko
- Department of Biomedical Science, University of South Alabama
| | - Donte A. Stevens
- Division of Biological Sciences, University of California-San Diego
| | - William M. Chilian
- Department of Integrative Medical Sciences, Northeast Ohio Medical University
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Kingma JG, Laher I. Effect of endothelin on sex-dependent regulation of tone in coronary resistance vessels. Biochem Biophys Res Commun 2021; 540:56-60. [PMID: 33445111 DOI: 10.1016/j.bbrc.2020.12.103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 12/30/2020] [Indexed: 01/16/2023]
Abstract
BACKGROUND/AIMS Sex dependent differences in coronary artery vasoregulation may be due to variations in responses to endogenous vasoactive compounds including endothelin (ET-1) and nitric oxide (NO). METHODS Septal coronary arteries (<200 μm) from healthy, sexually mature male, female and ovariectomized (i.e. surgical menopause) Sprague-Dawley rats were used. Myogenic tone, measured by pressure myography, was initially determined for all vessel segments studied before and after exposure to the nonselective ETA/ETB receptor blocker, bosentan (1 μM). Vasoconstrictor responses (vascular endothelium intact) to cumulative ET-1 (10-12 - 10-9 M) were assessed in a separate set of septal coronary vessels. Additional studies, examined the vasoconstrictor effects of ET-1 after NO blockade with L-NAME (200 μM). RESULTS Myogenic tone was 26 ± 7% in male, 20 ± 7% in female (p = 0.04 versus male) and 24 ± 3% in ovariectomized (p = NS versus male/female) vessels. Antagonism of ET-1 receptors produced a greater reduction in myogenic tone in male, compared to female rats over a similar range of intraluminal pressure (20-80 mmHg). Robust constrictor responses to cumulative concentrations of ET-1 were observed in all vessels; however, male rats exhibited greater sensitivity to vasoconstrictor effects of ET-1. After exposure to L-NAME vessel responses to ET-1 were normalized in male and female (not studied in ovariectomized) groups. CONCLUSIONS These findings confirm marked sex differences for myogenic tone and vessel constrictor responses to ET-1 in coronary resistance vessels. Results also suggest greater sensitivity to vasoconstrictor effects of ET-1 in male coronary resistance vessels.
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Affiliation(s)
- John G Kingma
- Department of Medicine, Faculty of Medicine, Pavillon Ferdinand-Vandry, 1050, Ave de la Médecine, Université Laval, Québec, Qc G1V 0A6, Canada.
| | - Ismail Laher
- Anesthesiology, Pharmacology and Therapeutics, Faculty of Medicine, 217 - 2176 Health, Sciences Mall, University of British Columbia, Vancouver, BC. V6T 1Z3, Canada
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Ohanyan V, Yin L, Bardakjian R, Kolz C, Enrick M, Hakobyan T, Kmetz J, Bratz I, Luli J, Nagane M, Khan N, Hou H, Kuppusamy P, Graham J, Fu FK, Janota D, Oyewumi MO, Logan S, Lindner JR, Chilian WM. Requisite Role of Kv1.5 Channels in Coronary Metabolic Dilation. Circ Res 2015. [PMID: 26224794 DOI: 10.1161/circresaha.115.306642] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
RATIONALE In the working heart, coronary blood flow is linked to the production of metabolites, which modulate tone of smooth muscle in a redox-dependent manner. Voltage-gated potassium channels (Kv), which play a role in controlling membrane potential in vascular smooth muscle, have certain members that are redox-sensitive. OBJECTIVE To determine the role of redox-sensitive Kv1.5 channels in coronary metabolic flow regulation. METHODS AND RESULTS In mice (wild-type [WT], Kv1.5 null [Kv1.5(-/-)], and Kv1.5(-/-) and WT with inducible, smooth muscle-specific expression of Kv1.5 channels), we measured mean arterial pressure, myocardial blood flow, myocardial tissue oxygen tension, and ejection fraction before and after inducing cardiac stress with norepinephrine. Cardiac work was estimated as the product of mean arterial pressure and heart rate. Isolated arteries were studied to establish whether genetic alterations modified vascular reactivity. Despite higher levels of cardiac work in the Kv1.5(-/-) mice (versus WT mice at baseline and all doses of norepinephrine), myocardial blood flow was lower in Kv1.5(-/-) mice than in WT mice. At high levels of cardiac work, tissue oxygen tension dropped significantly along with ejection fraction. Expression of Kv1.5 channels in smooth muscle in the null background rescued this phenotype of impaired metabolic dilation. In isolated vessels from Kv1.5(-/-) mice, relaxation to H2O2 was impaired, but responses to adenosine and acetylcholine were normal compared with those from WT mice. CONCLUSIONS Kv1.5 channels in vascular smooth muscle play a critical role in coupling myocardial blood flow to cardiac metabolism. Absence of these channels disassociates metabolism from flow, resulting in cardiac pump dysfunction and tissue hypoxia.
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Affiliation(s)
| | - Liya Yin
- Department of Integrative Medical Sciences
| | - Raffi Bardakjian
- Departement Internal Medicine, Canton Medical Education Foundation
| | | | | | | | - John Kmetz
- Department of Integrative Medical Sciences
| | - Ian Bratz
- Department of Integrative Medical Sciences
| | | | - Masaki Nagane
- Department of Radiology and Medicine, Geisel School of Medicine at Dartmouth College
| | - Nadeem Khan
- Department of Radiology and Medicine, Geisel School of Medicine at Dartmouth College
| | - Huagang Hou
- Department of Radiology and Medicine, Geisel School of Medicine at Dartmouth College
| | - Periannan Kuppusamy
- Department of Radiology and Medicine, Geisel School of Medicine at Dartmouth College
| | | | | | | | - Moses O Oyewumi
- Department of Pharmaceutical Sciences, Northeast Ohio Medical University
| | | | - Jonathan R Lindner
- Division of Cardiovascular Medicine, UHN62, Oregon Health and Science University
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Leblanc AJ, Chen B, Dougherty PJ, Reyes RA, Shipley RD, Korzick DH, Muller-Delp JM. Divergent effects of aging and sex on vasoconstriction to endothelin in coronary arterioles. Microcirculation 2014. [PMID: 23198990 DOI: 10.1111/micc.12028] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
OBJECTIVE The risk for cardiovascular disease increases with advancing age; however, the chronological development of heart disease differs in males and females. The purpose of this study was to determine whether age-induced alterations in responses of coronary arterioles to the endogenous vasoconstrictor, endothelin, are sex-specific. METHODS Coronary arterioles were isolated from young and old male and female rats to assess vasoconstrictor responses to endothelin (ET), and ETa and ETb receptor inhibitors were used to assess receptor-specific signaling. RESULTS In intact arterioles from males, ET-induced vasoconstriction was reduced with age, whereas age increased vasoconstrictor responses to ET in intact arterioles from female rats. In intact arterioles from both sexes, blockade of either ETa or ETb eliminated age-related differences in responses to ET; however, denudation of arterioles from both sexes revealed age-related differences in ETa-mediated vasoconstriction. In arterioles from male rats, ETa receptor protein decreased, whereas ETb receptor protein increased with age. In coronary arterioles from females, neither ETa nor ETb receptor protein changed with age, suggesting age-related changes in ET signaling occur downstream of ET receptors. CONCLUSIONS Thus, aging-induced alterations in responsiveness of the coronary resistance vasculature to endothelin are sex-specific, possibly contributing to sexual dimorphism in the risk of cardiovascular disease with advancing age.
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Affiliation(s)
- Amanda J Leblanc
- Center for Cardiovascular and Respiratory Sciences, School of Medicine, West Virginia University, Morgantown, WV, USA
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Kleinbongard P, Baars T, Möhlenkamp S, Kahlert P, Erbel R, Heusch G. Aspirate from human stented native coronary arteries vs. saphenous vein grafts: more endothelin but less particulate debris. Am J Physiol Heart Circ Physiol 2013; 305:H1222-9. [DOI: 10.1152/ajpheart.00358.2013] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Stent implantation into atherosclerotic coronary arteries releases particulate debris and soluble substances that contribute to impaired microvascular perfusion. Here we addressed the potential for microvascular obstruction in patients with stenotic native right coronary arteries (nRCA) compared with saphenous vein grafts on right coronary arteries (SVG-RCA). We enrolled symptomatic, male patients with stable angina pectoris and a flow-limiting stenosis in their nRCA or SVG-RCA ( n = 18/18). Plaque volume and composition were analyzed using intravascular ultrasound before stent implantation. Coronary aspirate was retrieved during stent implantation under protection with a distal occlusion/aspiration device and divided into particulate debris and plasma. The release of catecholamines, endothelin, serotonin, thromboxane B2, and tumor necrosis factor-α was measured. The response of rat mesenteric arteries with intact (+E) and denuded (−E) endothelium to aspirate plasma (without and with selective endothelin receptor blockade) was normalized to that by potassium chloride (KClmax = 100%). Plaque volume and composition were not different between nRCA and SVG-RCA. There was less particulate debris (65 ± 8 vs. 146 ± 23 mg; P < 0.05) and more endothelin release (5.8 ± 0.8 vs. 1.3 ± 0.7 pg/ml; P < 0.05) in nRCA than in SVG-RCA, whereas the release of the other mediators was not different. Aspirate from nRCA induced stronger vasoconstriction than that from SVG-RCA [nRCA, 78 ± 6% (+E)/84 ± 5% (−E); SVG-RCA, 59 ± 6% (+E)/68 ± 3% (−E); P < 0.05 nRCA vs. SVG-RCA], which was attenuated by a nonspecific endothelin and a specific endothelin receptor A antagonist. Thus coronary aspirate from stented nRCA is characterized by less debris but more endothelin and stronger vasoconstrictor response than that from SVG-RCA.
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Affiliation(s)
- Petra Kleinbongard
- Institut für Pathophysiologie, Universitätsklinikum Essen, Essen, Germany
| | - Theodor Baars
- Klinik für Kardiologie, Universitätsklinikum Essen, Essen, Germany; and
| | | | - Philipp Kahlert
- Klinik für Kardiologie, Universitätsklinikum Essen, Essen, Germany; and
| | - Raimund Erbel
- Klinik für Kardiologie, Universitätsklinikum Essen, Essen, Germany; and
| | - Gerd Heusch
- Institut für Pathophysiologie, Universitätsklinikum Essen, Essen, Germany
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6
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Chilian WM, Yin L, Ohanyan VA. Mysteries in the local control of blood flow: a physiological "whodunit" involving red cell release of ATP? Circ Res 2012; 111:156-7. [PMID: 22773423 DOI: 10.1161/circresaha.112.273060] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Endothelin-1 and norepinephrine overflow from cardiac sympathetic nerve endings in myocardial ischemia. Cardiol Res Pract 2012; 2012:789071. [PMID: 22792506 PMCID: PMC3389657 DOI: 10.1155/2012/789071] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2012] [Revised: 05/14/2012] [Accepted: 05/15/2012] [Indexed: 12/20/2022] Open
Abstract
In protracted myocardial ischemia, sympathetic activation with carrier-mediated excessive norepinephrine (NE) release from its nerve endings due to reversal of NE transporter in an outward direction is a prominent cause of arrhythmias and cardiac dysfunction. Endothelin-1 (ET-1) and its receptors are intimately involved in the regulation of this carrier-mediated NE overflow in protracted myocardial ischemia. The ET-1 system is often complex, sometimes involving opposing actions depending on which receptor subtype is activated, which cells are affected, and whether stimuli are endogenously generated or exogenously applied. Therefore, a detailed understanding of the ET-1 system is important for applying drugs acting on this system in clinical settings for the treatment of ischemic cardiac disease. This article provides a detailed analysis of how the ET-1 system is involved in the regulation of carrier-mediated NE release from sympathetic nerve endings in protracted myocardial ischemia.
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8
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Duncker DJ, Bache RJ, Merkus D. Regulation of coronary resistance vessel tone in response to exercise. J Mol Cell Cardiol 2012; 52:802-13. [DOI: 10.1016/j.yjmcc.2011.10.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Revised: 09/18/2011] [Accepted: 10/08/2011] [Indexed: 10/16/2022]
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9
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Favre J, Gao J, Zhang AD, Remy-Jouet I, Ouvrard-Pascaud A, Dautreaux B, Escoubet B, Thuillez C, Jaisser F, Richard V. Coronary endothelial dysfunction after cardiomyocyte-specific mineralocorticoid receptor overexpression. Am J Physiol Heart Circ Physiol 2011; 300:H2035-43. [PMID: 21441311 DOI: 10.1152/ajpheart.00552.2010] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The deleterious effects of aldosterone excess demonstrated in cardiovascular diseases might be linked in part to coronary vascular dysfunction. However, whether such vascular dysfunction is a cause or a consequence of the changes occurring in the cardiomyocytes is unclear. Moreover, the possible link between mineralocorticoid receptor (MR)-mediated effects on the cardiomyocyte and the coronary arteries is unknown. Thus we used a mouse model with conditional, cardiomyocyte-specific overexpression of human MR (hMR) and observed the effects on endothelial function in isolated coronary segments. hMR overexpression decreased the nitric oxide (NO)-mediated relaxing responses to acetylcholine in coronary arteries (but not in peripheral arteries), and this was prevented by a 1-mo treatment either with an MR antagonist, vitamin E/vitamin C, or a NADPH oxidase inhibitor. hMR overexpression did not affect coronary endothelial NO synthase content nor its level of phosphorylation on serine 1177, but increased cardiac levels of reactive oxygen species, cardiac NADPH oxidase (NOX) activity, and expression of the NOX subunit gp91phox, which was limited to endothelial cells. Thus an increase in hMR activation, restricted to cardiomyocytes, is sufficient to induce a severe coronary endothelial dysfunction. We suggest a new paracrine mechanism by which cardiomyocytes trigger a NOX-dependent, reactive oxygen species-mediated coronary endothelial dysfunction.
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Affiliation(s)
- Julie Favre
- Inserm U644, UFR Médecine-Pharmacie, 22 Boulevard Gambetta, 76183 Rouen Cedex, France
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Kohan DE, Rossi NF, Inscho EW, Pollock DM. Regulation of blood pressure and salt homeostasis by endothelin. Physiol Rev 2011; 91:1-77. [PMID: 21248162 DOI: 10.1152/physrev.00060.2009] [Citation(s) in RCA: 276] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Endothelin (ET) peptides and their receptors are intimately involved in the physiological control of systemic blood pressure and body Na homeostasis, exerting these effects through alterations in a host of circulating and local factors. Hormonal systems affected by ET include natriuretic peptides, aldosterone, catecholamines, and angiotensin. ET also directly regulates cardiac output, central and peripheral nervous system activity, renal Na and water excretion, systemic vascular resistance, and venous capacitance. ET regulation of these systems is often complex, sometimes involving opposing actions depending on which receptor isoform is activated, which cells are affected, and what other prevailing factors exist. A detailed understanding of this system is important; disordered regulation of the ET system is strongly associated with hypertension and dysregulated extracellular fluid volume homeostasis. In addition, ET receptor antagonists are being increasingly used for the treatment of a variety of diseases; while demonstrating benefit, these agents also have adverse effects on fluid retention that may substantially limit their clinical utility. This review provides a detailed analysis of how the ET system is involved in the control of blood pressure and Na homeostasis, focusing primarily on physiological regulation with some discussion of the role of the ET system in hypertension.
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Affiliation(s)
- Donald E Kohan
- Division of Nephrology, University of Utah Health Sciences Center, Salt Lake City, Utah 84132, USA.
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11
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de Beer VJ, Bender SB, Taverne YJ, Gao F, Duncker DJ, Laughlin MH, Merkus D. Exercise limits the production of endothelin in the coronary vasculature. Am J Physiol Heart Circ Physiol 2011; 300:H1950-9. [PMID: 21317308 DOI: 10.1152/ajpheart.00954.2010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We previously demonstrated that endothelin (ET)-mediated coronary vasoconstriction wanes with increasing exercise intensity via a nitric oxide- and prostacyclin-dependent mechanism (Ref. 23). Therefore, we hypothesized that the waning of ET coronary vasoconstriction during exercise is the result of decreased production of ET and/or decreased ET receptor sensitivity. We investigated coronary ET receptor sensitivity using intravenous infusion of ET and coronary ET production using intravenous infusion of the ET precursor Big ET, at rest and during continuous treadmill exercise at 3 km/h in 16 chronically instrumented swine. In the systemic vasculature, Big ET and ET induced similar changes in hemodynamic parameters at rest and during continuous exercise at 3 km/h, indicating that exercise does not alter ET production or receptor sensitivity in the systemic vasculature. In the coronary vasculature, infusion of ET resulted in similar dose-dependent decreases in coronary blood flow and coronary venous oxygen tension and saturation at rest and during exercise. In contrast, administration of Big ET resulted in dose-dependent decreases in coronary blood flow, as well as coronary venous oxygen tension and saturation at rest. These effects of Big ET were significantly reduced during exercise. Altogether, our data indicate that continuous exercise at 3 km/h attenuates ET-mediated coronary vasoconstriction through reduced production of ET from Big ET rather than through reduced ET sensitivity of the coronary vasculature. The decreased ET production during exercise likely contributes to metabolic coronary vasodilation.
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Affiliation(s)
- Vincent J de Beer
- Division of Experimental Cardiology, Department of Cardiology, Thoraxcenter, he Netherlands.
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12
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Gao MH, Tang T, Lai NC, Miyanohara A, Guo T, Tang R, Firth AL, Yuan JX, Hammond HK. Beneficial effects of adenylyl cyclase type 6 (AC6) expression persist using a catalytically inactive AC6 mutant. Mol Pharmacol 2010; 79:381-8. [PMID: 21127130 DOI: 10.1124/mol.110.067298] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Cardiac-directed expression of AC6 has pronounced favorable effects on cardiac function possibly not linked with cAMP production. To determine rigorously whether cAMP generation is required for the beneficial effects of increased AC6 expression, we generated a catalytically inactive AC6 mutant (AC6mut) that has markedly diminished cAMP generating capacity by replacing aspartic acid with alanine at position 426 in the C1 domain (catalytic region) of AC6. Gene transfer of AC6 or AC6mut (adenovirus-mediated) in adult rat cardiac myocytes resulted in similar expression levels and intracellular distribution, but AC6mut expression was associated with marked reduction in cAMP production. Despite marked reduction in cAMP generation, AC6mut influenced intracellular signaling events similarly to that observed after expression of catalytically intact AC6. For example, both AC6 and AC6mut reduced phenylephrine-induced cardiac myocyte hypertrophy and apoptosis (p < 0.001), expression of cardiac ankyrin repeat protein (p < 0.01), and phospholamban (p < 0.05). AC6mut expression, similar to its catalytically intact cohort, was associated with increased Ca2+ transients in cardiac myocytes after isoproterenol stimulation. Many of the biological effects of AC6 expression are replicated by a catalytically inactive AC6 mutant, indicating that the mechanisms for these effects do not require increased cAMP generation.
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Affiliation(s)
- Mei Hua Gao
- Department of Medicine, University of California San Diego, Veterans Affairs San Diego Healthcare System, La Jolla, CA 92161, USA.
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Machii H, Saitoh SI, Kaneshiro T, Takeishi Y. Aging impairs myocardium-induced dilation in coronary arterioles: role of hydrogen peroxide and angiotensin. Mech Ageing Dev 2010; 131:710-7. [PMID: 20965209 DOI: 10.1016/j.mad.2010.09.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Revised: 08/27/2010] [Accepted: 09/30/2010] [Indexed: 10/18/2022]
Abstract
The mechanisms that drive age-related modifications of coronary circulation by myocardium have not been fully defined. To elucidate the aging effect on myocyte-induced vascular response, we measured changes in the diameter of isolated coronary arterioles to supernatant collected from isolated cardiac myocytes of young (2 mo) and old (24 mo) rats (stimulated at 400 beats/min, n=10, each). The H(2)O(2) level in pacing myocyte supernatant was greater in old rats than in young ones (15.9±1.8 vs. 9.5±0.7μM, P<0.01). Catalase activity in myocytes decreased 38.6±5.2% in old rats compared to that in young rats. Vasodilation with young-myocyte supernatant (M) (response to 500μl; young-arterioles (A) 20.5±1.6%, old-A 18.2±1.2%) was more potent compared to that with old-M (young-A 10.3±0.8%, old-A 9.4±1.0%, P<0.01, respectively). Treatment with an angiotensin II receptor antagonist, olmesartan, in a vessel bath augmented vasodilation in old-M+young-A (34.9±4.0%, P<0.01) and old-M+old-A (27.2±2.8%, P<0.01). Administration of catalase converted vasodilation to vasoconstriction in old-M and eliminated vasodilation in young-M. Vascular responses with authentic H(2)O(2) and angiotensin II were similar between old- and young-A. Thus, aging increases both angiotensin and the H(2)O(2) release from myocardium. In conclusion, cardiac myocyte-dependent signaling plays an important role in determining coronary vascular tone in the aging heart.
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Affiliation(s)
- Hirofumi Machii
- Department of Cardiology and Hematology, Fukushima Medical University, Hikarigaoka, Fukushima 960-1295, Japan
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Acute subepicardial infarction associated with severe septic shock--insight in myocardial perfusion. Pathol Res Pract 2009; 206:401-4. [PMID: 19945802 DOI: 10.1016/j.prp.2009.11.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2009] [Revised: 10/08/2009] [Accepted: 11/02/2009] [Indexed: 11/23/2022]
Abstract
Isolated infarctions of the subepicardial myocardium without changes in subendocardium are extremely rare. We present an autoptic case with an acute subepicardial infarction of the right- and left-ventricular myocardium. A 53-year-old male was admitted to hospital with acute upper abdominal pain. Clinical examination revealed an acute infero-lateral myocardial infarction. The patient succumbed to acute heart failure a few hours later. Autopsy revealed numerous pulmonary abscesses due to suppurative lobular pneumonia with consecutive pericardial effusion. Furthermore, we diagnosed an acute myocardial infarct encompassing the entire right and left ventricles but limited to the subepicardial myocardium only. Microscopically, we observed fibrin microemboli in the subepicardial microvessels. The existence of an isolated subepicardial myocardial infarct challenges our understanding of myocardial perfusion.
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Yamaguchi O, Kaneshiro T, Saitoh SI, Ishibashi T, Maruyama Y, Takeishi Y. Regulation of coronary vascular tone via redox modulation in the alpha1-adrenergic-angiotensin-endothelin axis of the myocardium. Am J Physiol Heart Circ Physiol 2008; 296:H226-32. [PMID: 19028798 DOI: 10.1152/ajpheart.00480.2008] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
We hypothesized that alpha(1)-adrenoceptor stimulation of cardiac myocytes results in the production of an endothelin (ET)-releasing factor that stimulates the coronary vasculature to release ET and, by manipulating the redox state of cardiac and vascular cells, may influence the extent of alpha(1)-adrenergic-ET-1 vasoconstriction. Dihydroethidium (DHE) and dichlorodihydrofluorescein (DCF) intensities were increased by phenylephrine stimulation in isolated rat cardiac myocytes, which were enhanced by the mitochondrial electron transport chain complex I inhibitor rotenone (DHE: 20.4 +/- 1.2-fold and DCF: 25.2 +/- 0.9-fold, n = 8, P < 0.01, respectively) but not by the NADPH oxidase inhibitor apocynin. Olmesartan, an angiotensin II type 1 receptor antagonist, and enalaprilate did not change DHE and DCF intensities by phenylephrine. Next, we measured the vasoconstriction of isolated, pressurized rat coronary arterioles (diameter: 74 +/- 8 microm) in response to supernatant collected from isolated cardiac myocytes. The addition of supernatant from phenylephrine-stimulated myocytes to a 2-ml vessel bath (n = 8 each) caused volume-dependent vasoconstriction (500 microl: -14.8 +/- 2.2%). Olmesartan and TA0201, an ET type A receptor antagonist, converted vasoconstriction into vasodilation (8.5 +/- 1.2% and 10.5 +/- 0.5%, P < 0.01, respectively) in response to supernatant from phenylephrine-stimulated myocytes, which was eliminated with catalase. Vasoconstriction was weakened using supernatant from phenylephrine with rotenone-treated myocytes. Treatment of arterioles with apocynin to myocyte supernatant converted vasoconstriction into vasodilation (7.8 +/- 0.8%, P < 0.01). These results suggest that alpha(1)-adrenergic stimulation in cardiac myocytes produces angiotensin I and H(2)O(2) and that angiotensin releases ET-1 through NADPH oxidase in coronary arterioles. Thus, coronary vasoconstriction via the alpha-adrenergic-angiotensin-ET axis appears to require redox-mediated signaling in cardiac and vascular cells.
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Affiliation(s)
- Osamu Yamaguchi
- First Dept. of Internal Medicine, Fukushima Medical Univ., 1 Hikarigaoka, Fukushima 960-1295, Japan
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de Beer VJ, Sorop O, Pijnappels DA, Dekkers DH, Boomsma F, Lamers JMJ, Duncker DJ, Merkus D. Integrative control of coronary resistance vessel tone by endothelin and angiotensin II is altered in swine with a recent myocardial infarction. Am J Physiol Heart Circ Physiol 2008; 294:H2069-77. [DOI: 10.1152/ajpheart.01163.2007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Several studies have indicated an interaction between the renin-angiotensin (ANG II) system and endothelin (ET) in the regulation of vascular tone. Previously, we have shown that both ET and ANG II exert a vasoconstrictor influence on the coronary resistance vessels of awake normal swine. Here, we investigated whether the interaction between ANG II and ET exists in the control of coronary resistance vessel tone at rest and during exercise using single and combined blockade of angiotensin type 1 (AT1) and ETA/ETB receptors. Since both circulating ANG II and ET levels are increased after myocardial infarction (MI), we investigated if the interaction between these systems is altered after MI. In awake healthy swine, coronary vasodilation in response to ETA/ETB receptor blockade in the presence of AT1 blockade was similar to vasodilation produced by ETA/ETB blockade under control conditions. In awake swine with a 2- to 3-wk-old MI, coronary vasodilator responses to individual AT1 and ETA/ETB receptor blockade were virtually abolished, despite similar coronary arteriolar AT1 and ETA receptor expression compared with normal swine. Unexpectedly, in the presence of AT1 blockade (which had no effect on circulating ET levels), ETA/ETB receptor blockade elicited a coronary vasodilator response. These findings suggest that in normal healthy swine the two vasoconstrictor systems contribute to coronary resistance vessel control in a linear additive manner, i.e., with negligible cross-talk. In contrast, in the remodeled myocardium, cross-talk between ANG II and ET emerges, resulting in nonlinear redundant control of coronary resistance vessel tone.
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Tune JD. Withdrawal of vasoconstrictor influences in local metabolic coronary vasodilation. Am J Physiol Heart Circ Physiol 2006; 291:H2044-6. [PMID: 16844914 DOI: 10.1152/ajpheart.00653.2006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Sun X, Ku DD. Selective right, but not left, coronary endothelial dysfunction precedes development of pulmonary hypertension and right heart hypertrophy in rats. Am J Physiol Heart Circ Physiol 2006; 290:H758-64. [PMID: 16172159 DOI: 10.1152/ajpheart.00647.2005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We investigated a causal role for coronary endothelial dysfunction in development of monocrotaline (MCT)-induced pulmonary hypertension and right heart hypertrophy in rats. Significant increases in pulmonary pressure and right ventricular weight did not occur until 3 wk after 60 mg/kg MCT injection (34 ± 4 vs. 19 ± 2 mmHg and 37 ± 2 vs. 25 ± 1% septum + left ventricular weight in controls, respectively). Isolated right coronary arteries (RCA) showed significant decreases in acetylcholine-induced NO dilation in both 1-wk (33 ± 3% with 0.3 μM; n = 5) and 3-wk (18 ± 3%; n = 11) MCT rats compared with control rats (71 ± 8%, n = 10). Septal coronary arteries (SCA) showed a smaller decrease in acetylcholine dilation (55 ± 8% and 33 ± 7%, respectively, vs. 73 ± 8% in controls). No significant change was found in the left coronary arteries (LCA; 88 ± 6% and 81 ± 6%, respectively, vs. 87 ± 3% in controls). Nitro-l-arginine methyl ester-induced vasoconstriction, an estimate of spontaneous endothelial NO-mediated dilation, was not significantly altered in MCT-treated SCA or LCA but was increased in RCA after 1 wk of MCT (−41 ± 6%) and decreased after 3 wk (−18 ± 3% vs. −27 ± 3% in controls). A marked enhancement to 30 nM U-46619-induced constriction was also noted in RCA of 3-wk (−28 ± 6% vs. −9 ± 2% in controls) but not 1-wk (−12 ± 7%) MCT rats. Sodium nitroprusside-induced vasodilation was not different between control and MCT rats. Together, our findings show that a selective impairment of right, but not left, coronary endothelial function is associated with and precedes development of MCT-induced pulmonary hypertension and right heart hypertrophy in rats.
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Affiliation(s)
- Xiaowei Sun
- Dept. of Pharmacology and Toxicology, Univ. of Alabama at Birmingham, 1530 3rd Ave. S., Birmingham, AL 35294-0019, USA
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Pikkarainen S, Tokola H, Kerkelä R, Ilves M, Mäkinen M, Orzechowski HD, Paul M, Vuolteenaho O, Ruskoaho H. Inverse regulation of preproendothelin-1 and endothelin-converting enzyme-1beta genes in cardiac cells by mechanical load. Am J Physiol Regul Integr Comp Physiol 2006; 290:R1639-45. [PMID: 16410403 DOI: 10.1152/ajpregu.00559.2005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mechanical stretch and para- and/or autocrine factors, including endothelin-1, induce hypertrophy of cardiac myocytes and proliferation of fibroblasts. To investigate the effect of mechanical load on endothelin-1 production and endothelin system gene expression in neonatal rat ventricular myocytes and fibroblasts, we exposed cells to cyclic mechanical stretch in vitro (0.5 Hz, 10-25% elongation, from 1 min to 24 h). Endothelin-1 peptide levels were measured from culture media of myocytes and fibroblasts and human umbilical vein endothelial cells (positive control) by specific radioimmunoassay. Preproendothelin-1 promoter activity was measured via transfection of reporter plasmids and mRNA levels with Northern blot analysis or quantitative RT-PCR. Activity of extracellular signal-regulated kinase was quantified with specific kinase assay. We found that stretching of myocytes activated preproendothelin-1 gene expression, including promoter activation, transient mRNA level increases, and augmented endothelin-1 secretion. In contrast, preproendothelin-1 gene expression was inhibited in stretched fibroblasts. Endothelin-converting enzyme-1beta mRNA levels elevated in stretched fibroblasts but decreased in stretched myocytes. Endothelin receptor type A mRNA levels declined in stretched myocytes, whereas levels were below detection in fibroblasts. Stretch activated extracellular signal-regulated kinase in myocytes, and when the kinase activity was pharmacologically inhibited, the preproendothelin-1 induction was suppressed. Transient overexpression of mitogen-activated ERK-activating kinase-1 induced preproendothelin-1 promoter in myocytes. In summary, mechanical stretch distinctly regulates endothelin system gene expression in cardiac myocytes and fibroblasts. The inhibition of the endothelin system may affect cardiac mechanotransduction and therefore provides an approach in treatment of load-induced cardiac pathology.
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Affiliation(s)
- Sampsa Pikkarainen
- Department of Pharmacology and Toxicology, Biocenter Oulu, University of Oulu, Finland
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Abstract
During the past three decades, percutaneous coronary intervention has become one of the cardinal treatment strategies for stenotic coronary artery disease. Technical advances, including the introduction of new devices such as stents, have expanded the interventional capabilities of balloon angioplasty. At the same time, there has been a decline in the rate of major adverse cardiac events, including Q-wave acute myocardial infarction, emergency coronary artery bypass grafting, and cardiac death. Despite these advances, the incidence of post-procedural cardiac marker elevation has not substantially decreased since the first serial assessment 20 years ago. As of now, these post-procedural cardiac marker elevations are considered to represent peri-procedural myocardial injury (PMI) with worse long-term outcome potential. Recent progress has been made for the identification of two main PMI patterns, one near the intervention site (proximal type, PMI type I) and one in the distal perfusion territory of the treated coronary artery (distal type, PMI type II) as well as for preventive strategies. Integrating these new developments into the wealth of clinical information on this topic, this review aims at giving a current perspective on the entity of PMI.
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Affiliation(s)
- Joerg Herrmann
- Department of Internal Medicine, Mayo Clinic Rochester, 200 First Street S.W., Rochester, MN 55905, USA.
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