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Sorop O, van de Wouw J, Merkus D, Duncker DJ. Coronary Microvascular Dysfunction in Cardiovascular Disease: Lessons from Large Animal Models. Microcirculation 2020. [DOI: 10.1007/978-3-030-28199-1_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Olver TD, Edwards JC, Ferguson BS, Hiemstra JA, Thorne PK, Hill MA, Laughlin MH, Emter CA. Chronic interval exercise training prevents BK Ca channel-mediated coronary vascular dysfunction in aortic-banded miniswine. J Appl Physiol (1985) 2018; 125:86-96. [PMID: 29596016 DOI: 10.1152/japplphysiol.01138.2017] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Conventional treatments have failed to improve the prognosis of heart failure with preserved ejection fraction (HFpEF) patients. Thus, the purpose of this study was to determine the therapeutic efficacy of chronic interval exercise training (IT) on large-conductance Ca2+-activated K+ (BKCa) channel-mediated coronary vascular function in heart failure. We hypothesized that chronic interval exercise training would attenuate pressure overload-induced impairments to coronary BKCa channel-mediated function. A translational large-animal model with cardiac features of HFpEF was used to test this hypothesis. Specifically, male Yucatan miniswine were divided into three groups ( n = 7/group): control (CON), aortic banded (AB)-heart failure (HF), and AB-interval trained (HF-IT). Coronary blood flow, vascular conductance, and vasodilatory capacity were measured after administration of the BKCa channel agonist NS-1619 both in vivo and in vitro in the left anterior descending coronary artery and isolated coronary arterioles, respectively. Skeletal muscle citrate synthase activity was decreased and left ventricular brain natriuretic peptide levels increased in HF vs. CON and HF-IT animals. A parallel decrease in NS-1619-dependent coronary vasodilatory reserve in vivo and isolated coronary arteriole vasodilatory responsiveness in vitro were observed in HF animals compared with CON, which was prevented in the HF-IT group. Although exercise training prevented BKCa channel-mediated coronary vascular dysfunction, it did not change BKCa channel α-subunit mRNA, protein, or cellular location (i.e., membrane vs. cytoplasm). In conclusion, these results demonstrate the viability of chronic interval exercise training as a therapy for central and peripheral adaptations of experimental heart failure, including BKCa channel-mediated coronary vascular dysfunction. NEW & NOTEWORTHY Conventional treatments have failed to improve the prognosis of heart failure with preserved ejection fraction (HFpEF) patients. Our findings show that chronic interval exercise training can prevent BKCa channel-mediated coronary vascular dysfunction in a translational swine model of chronic pressure overload-induced heart failure with relevance to human HFpEF.
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Affiliation(s)
- T Dylan Olver
- Department of Biomedical Sciences, University of Missouri-Columbia , Columbia, Missouri
| | - Jenna C Edwards
- Department of Biomedical Sciences, University of Missouri-Columbia , Columbia, Missouri
| | - Brian S Ferguson
- Department of Biomedical Sciences, University of Missouri-Columbia , Columbia, Missouri
| | - Jessica A Hiemstra
- Department of Biomedical Sciences, University of Missouri-Columbia , Columbia, Missouri
| | - Pamela K Thorne
- Department of Biomedical Sciences, University of Missouri-Columbia , Columbia, Missouri
| | - Michael A Hill
- Dalton Cardiovascular Research Center, University of Missouri-Columbia , Columbia, Missouri.,Department of Medical Pharmacology and Physiology, University of Missouri-Columbia , Columbia, Missouri
| | - M Harold Laughlin
- Department of Biomedical Sciences, University of Missouri-Columbia , Columbia, Missouri.,Dalton Cardiovascular Research Center, University of Missouri-Columbia , Columbia, Missouri.,Department of Medical Pharmacology and Physiology, University of Missouri-Columbia , Columbia, Missouri
| | - Craig A Emter
- Department of Biomedical Sciences, University of Missouri-Columbia , Columbia, Missouri
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Rapoport RM, Merkus D. Endothelin-1 Regulation of Exercise-Induced Changes in Flow: Dynamic Regulation of Vascular Tone. Front Pharmacol 2017; 8:517. [PMID: 29114220 PMCID: PMC5660699 DOI: 10.3389/fphar.2017.00517] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 07/24/2017] [Indexed: 12/12/2022] Open
Abstract
Although endothelin (ET)-1 is a highly potent vasoconstrictor with considerable efficacy in numerous vascular beds, the role of endogenous ET-1 in the regulation of vascular tone remains unclear. The perspective that ET-1 plays little role in the on-going regulation of vascular tone at least under physiologic conditions is supported by findings that potential ET-1 constriction is minimized by the release of the vasodilator and ET-1 synthesis inhibitor, nitric oxide (NO). Indeed, ET-1 release and constriction is self-limited by ET-1-induced, endothelial ETB receptor-mediated release of NO. Moreover, even if the balance between ET-1 and NO were reversed as the result of lowered NO activity, as occurs in a number of pathophysiologies associated with endothelial dysfunction, the well-known resistance of ET-1 constriction to reversal (as determined with exogenous ET-1) precludes ET-1 in the dynamic, i.e., moment-to-moment, regulation of vascular tone. On the other hand, and as presently reviewed, findings of ET-1-dependent modulation of organ blood flow with exercise under physiologic conditions demonstrate the dynamic regulation of vascular tone by ET-1. We speculate that this regulation is mediated at least in part through changes in ET-1 synthesis/release caused by pulsatile flow-induced shear stress and NO.
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Affiliation(s)
- Robert M Rapoport
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Daphne Merkus
- Division of Experimental Cardiology, Department of Cardiology, Thoraxcenter, Cardiovascular Research School COEUR, Erasmus University Medical School Rotterdam, Rotterdam, Netherlands
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Skovsted GF, Tveden-Nyborg P, Lindblad MM, Hansen SN, Lykkesfeldt J. Vitamin C Deficiency Reduces Muscarinic Receptor Coronary Artery Vasoconstriction and Plasma Tetrahydrobiopterin Concentration in Guinea Pigs. Nutrients 2017; 9:E691. [PMID: 28671625 PMCID: PMC5537806 DOI: 10.3390/nu9070691] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 06/23/2017] [Accepted: 06/29/2017] [Indexed: 12/15/2022] Open
Abstract
Vitamin C (vitC) deficiency is associated with increased cardiovascular disease risk, but its specific interplay with arteriolar function is unclear. This study investigates the effect of vitC deficiency in guinea pigs on plasma biopterin status and the vasomotor responses in coronary arteries exposed to vasoconstrictor/-dilator agents. Dunkin Hartley female guinea pigs (n = 32) were randomized to high (1500 mg/kg diet) or low (0 to 50 mg/kg diet) vitC for 10-12 weeks. At euthanasia, coronary artery segments were dissected and mounted in a wire-myograph. Vasomotor responses to potassium, carbachol, sodium nitroprusside (SNP), U46619, sarafotoxin 6c (S6c) and endothelin-1 (ET-1) were recorded. Plasma vitC and tetrahydrobiopterin were measured by HPLC. Plasma vitC status reflected the diets with deficient animals displaying reduced tetrahydrobiopterin. Vasoconstrictor responses to carbachol were significantly decreased in vitC deficient coronary arteries independent of their general vasoconstrictor/vasodilator capacity (p < 0.001). Moreover, in vitC deficient animals, carbachol-induced vasodilator responses correlated with coronary artery diameter (p < 0.001). Inhibition of cyclooxygenases with indomethacin increased carbachol-induced vasoconstriction, suggesting an augmented carbachol-induced release of vasodilator prostanoids. Atropine abolished carbachol-induced vasomotion, supporting a specific muscarinic receptor effect. Arterial responses to SNP, potassium, S6c, U46619 and ET-1 were unaffected by vitC status. The study shows that vitC deficiency decreases tetrahydrobiopterin concentrations and muscarinic receptor mediated contraction in coronary arteries. This attenuated vasoconstrictor response may be linked to altered production of vasoactive arachidonic acid metabolites and reduced muscarinic receptor expression/signaling.
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Affiliation(s)
- Gry Freja Skovsted
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Ridebanevej 9, 1870 Frederiksberg C, Denmark.
| | - Pernille Tveden-Nyborg
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Ridebanevej 9, 1870 Frederiksberg C, Denmark.
| | - Maiken Marie Lindblad
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Ridebanevej 9, 1870 Frederiksberg C, Denmark.
| | - Stine Normann Hansen
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Ridebanevej 9, 1870 Frederiksberg C, Denmark.
| | - Jens Lykkesfeldt
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Ridebanevej 9, 1870 Frederiksberg C, Denmark.
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Heinonen I, Sorop O, de Beer VJ, Duncker DJ, Merkus D. What can we learn about treating heart failure from the heart's response to acute exercise? Focus on the coronary microcirculation. J Appl Physiol (1985) 2015; 119:934-43. [PMID: 26048972 DOI: 10.1152/japplphysiol.00053.2015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Coronary microvascular function and cardiac function are closely related in that proper cardiac function requires adequate oxygen delivery through the coronary microvasculature. Because of the close proximity of cardiomyocytes and coronary microvascular endothelium, cardiomyocytes not only communicate their metabolic needs to the coronary microvasculature, but endothelium-derived factors also directly modulate cardiac function. This review summarizes evidence that the myocardial oxygen balance is disturbed in the failing heart because of increased extravascular compressive forces and coronary microvascular dysfunction. The perturbations in myocardial oxygen balance are exaggerated during exercise and are due to alterations in neurohumoral influences, endothelial function, and oxidative stress. Although there is some evidence from animal studies that the myocardial oxygen balance can partly be restored by exercise training, it is largely unknown to what extent the beneficial effects of exercise training include improvements in endothelial function and/or oxidative stress in the coronary microvasculature and how these improvements are impacted by risk factors such as diabetes, obesity, and hypercholesterolemia.
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Affiliation(s)
- Ilkka Heinonen
- Division of Experimental Cardiology, Thoraxcenter, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands; and Turku PET Centre, University of Turku and Turku University Hospital, Turku, Finland
| | - Oana Sorop
- Division of Experimental Cardiology, Thoraxcenter, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands; and
| | - Vincent J de Beer
- Division of Experimental Cardiology, Thoraxcenter, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands; and
| | - Dirk J Duncker
- Division of Experimental Cardiology, Thoraxcenter, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands; and
| | - Daphne Merkus
- Division of Experimental Cardiology, Thoraxcenter, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands; and
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Rapoport RM. Acute nitric oxide synthase inhibition and endothelin-1-dependent arterial pressure elevation. Front Pharmacol 2014; 5:57. [PMID: 24744731 PMCID: PMC3978292 DOI: 10.3389/fphar.2014.00057] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Accepted: 03/15/2014] [Indexed: 11/13/2022] Open
Abstract
Key evidence that endogenous nitric oxide (NO) inhibits the continuous, endothelin (ET)-1-mediated drive to elevate arterial pressure includes demonstrations that ET-1 mediates a significant component of the pressure elevated by acute exposure to NO synthase (NOS) inhibitors. This review examines the characteristics of this pressure elevation in order to elucidate potential mechanisms associated with the negative regulation of ET-1 by NO and, thereby, provide potential insight into the vascular pathophysiology underlying NO dysregulation. We surmise that the magnitude of the ET-1-dependent component of the NOS inhibitor-elevated pressure is (1) independent of underlying arterial pressure and other pressor pathways activated by the NOS inhibitors and (2) dependent on relatively higher NOS inhibitor dose, release of stored and de novo synthesized ET-1, and ETA receptor-mediated increased vascular resistance. Major implications of these conclusions include: (1) the marked variation of the ET-1-dependent component, i.e., from 0 to 100% of the pressure elevation, reflects the NO-ET-1 regulatory pathway. Thus, NOS inhibitor-mediated, ET-1-dependent pressure elevation in vascular pathophysiologies is an indicator of the level of compromised/enhanced function of this pathway; (2) NO is a more potent inhibitor of ET-1-mediated elevated arterial pressure than other pressor pathways, due in part to inhibition of intravascular pressure-independent release of ET-1. Thus, the ET-1-dependent component of pressure elevation in vascular pathophysiologies associated with NO dysregulation is of greater magnitude at higher levels of compromised NO.
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Affiliation(s)
- Robert M Rapoport
- Research Service, Department of Pharmacology and Cell Biophysics, Veterans Affairs Medical Center, University of Cincinnati College of Medicine Cincinnati, OH, USA
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Zhou Z, de Beer VJ, Bender SB, Jan Danser AH, Merkus D, Laughlin MH, Duncker DJ. Phosphodiesterase-5 activity exerts a coronary vasoconstrictor influence in awake swine that is mediated in part via an increase in endothelin production. Am J Physiol Heart Circ Physiol 2014; 306:H918-27. [PMID: 24464751 DOI: 10.1152/ajpheart.00331.2013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nitric oxide (NO)-induced coronary vasodilation is mediated through production of cyclic guanosine monophosphate (cGMP) and through inhibition of the endothelin-1 (ET) system. We previously demonstrated that phosphodiesterase-5 (PDE5)-mediated cGMP breakdown and ET each exert a vasoconstrictor influence on coronary resistance vessels. However, little is known about the integrated control of coronary resistance vessel tone by these two vasoconstrictor mechanisms. In the present study, we investigated the contribution of PDE5 and ET to the regulation of coronary resistance vessel tone in swine both in vivo, at rest and during graded treadmill exercise, and in vitro. ETA/ETB receptor blockade with tezosentan (3 mg/kg iv) and PDE5 inhibition with EMD360527 (300 μg·min(-1)·kg(-1) iv) each produced coronary vasodilation at rest and during exercise as well as in preconstricted isolated coronary small arteries. In contrast, tezosentan failed to produce further coronary vasodilation in the presence of EMD360527, both in vivo and in vitro. Importantly, EMD360527 (3 μM) and cGMP analog 8-Br-cGMP (100 μM) had no significant effects on ET-induced contractions of isolated porcine coronary small arteries, suggesting unperturbed ET receptor responsiveness. In contrast, PDE5 inhibition and cGMP blunted the contractions produced by the ET precursor Big ET, but only in vessels with intact endothelium, suggesting that PDE5 inhibition limited ET production in the endothelium of small coronary arteries. In conclusion, PDE5 activity exerts a vasoconstrictor influence on coronary resistance vessels that is mediated, in part, via an increase in endothelial ET production.
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Affiliation(s)
- Zhichao Zhou
- Division of Experimental Cardiology, Department of Cardiology, Thoraxcenter, Cardiovascular Research School COEUR, Erasmus University Medical Center Rotterdam, Rotterdam, The Netherlands
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Merkus D, Duncker DJ. Perspectives: Coronary microvascular dysfunction in post-infarct remodelled myocardium. Eur Heart J Suppl 2014. [DOI: 10.1093/eurheartj/sut016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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9
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Zhou Z, de Wijs-Meijler D, Lankhuizen I, Jankowski J, Jankowski V, Jan Danser AH, Duncker DJ, Merkus D. Blunted coronary vasodilator response to uridine adenosine tetraphosphate in post-infarct remodeled myocardium is due to reduced P1 receptor activation. Pharmacol Res 2013; 77:22-9. [PMID: 23994209 DOI: 10.1016/j.phrs.2013.08.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 08/13/2013] [Accepted: 08/19/2013] [Indexed: 11/26/2022]
Abstract
We previously demonstrated that uridine adenosine tetraphosphate (Up4A) exerts a potent vasodilator effect in the healthy porcine coronary vasculature. Since the coronary microvascular effects of Up4A after myocardial infarction (MI) are unknown, the present study investigated the response to Up4A in coronary microvessels from post-MI remodeled porcine myocardium, and the involvement of purinergic receptor subtypes. Coronary small arteries (diameter ∼150 μm) were dissected from the apex of Sham-operated swine and swine in which MI had been produced 5 weeks earlier by transient (2h) occlusion of the left circumflex coronary artery, and mounted on Mulvany wire myographs. Up4A (10(-9)-10(-5)M) produced coronary vasodilation that was reduced in MI as compared to Sham-operated swine. Up4A-induced vasodilation was reduced by P1 blockade with 8-phenyltheophylline in Sham-operated swine and to a lesser extent in MI, while the attenuation by the A2A receptor blocker SCH58261 was similar in Sham-operated and MI swine. Up4A-induced vasodilation remained unaffected by non-selective P2 receptor antagonist PPADS, but was attenuated by selective P2X1 and P2Y1 receptor antagonists MRS2159 and MRS2179, albeit to a similar extent in Sham-operated and MI swine. These responses were paralleled by similar mRNA expression levels of A2A, P2X1 and P2Y1 receptors in MI compared to slaughterhouse control swine. Finally, attenuation of Up4A-induced coronary vasodilation by nitric oxide synthase inhibition was not attenuated in MI as compared to Sham-operated swine. In conclusion, blunted coronary vasodilation in response to Up4A in MI swine is most likely due to reduced activation of P1, rather than P2, receptors and does not involve a loss of NO bioavailability.
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Affiliation(s)
- Zhichao Zhou
- Division of Experimental Cardiology, Department of Cardiology, Thoraxcenter, Cardiovascular Research School COEUR, The Netherlands
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Merkus D, Visser M, Houweling B, Zhou Z, Nelson J, Duncker DJ. Phosphodiesterase 5 inhibition-induced coronary vasodilation is reduced after myocardial infarction. Am J Physiol Heart Circ Physiol 2013; 304:H1370-81. [DOI: 10.1152/ajpheart.00410.2012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The balance between the production and removal of cGMP in coronary vascular smooth muscle is of critical importance in determining coronary vasomotor tone and thus in the regulation of coronary blood flow. cGMP production by soluble guanylyl cyclase is activated by nitric oxide (NO), whereas cGMP breakdown occurs through phosphodiesterase 5 (PDE5). We hypothesized that myocardial infarction (MI) alters the balance between the production and removal of cGMP in the coronary vasculature and thereby alters the control of coronary vasomotor tone. Chronically instrumented swine with and without a 2-wk-old MI were exercised on a treadmill in the absence and presence of the PDE5 inhibitor EMD-360527 (300 μg·kg−1·min−1 iv). Inhibition of PDE5 produced coronary resistance vessel dilation, which was more pronounced at rest than during exercise in normal swine. PDE5 gene expression was markedly reduced in coronary resistance vessels isolated from the remote myocardium of MI swine, which was accompanied by a similarly marked attenuation of coronary vasodilation by PDE5 inhibition in MI swine. The coronary vasoconstriction produced by inhibition of NO synthesis with Nω-nitro-l-arginine (20 mg/kg iv) was only slightly smaller in swine with MI. Interestingly, inhibition of NO synthesis reduced the vasodilator response to subsequent PDE5 inhibition in normal swine but not in MI swine. Conversely, PDE5 inhibition enhanced the coronary vasoconstriction produced by NO synthesis inhibition in normal swine but not in MI swine, suggesting that downregulation of PDE5 mitigated the loss of NO vasodilator influence. In conclusion, the expression and vasoconstrictor influence of PDE5 are markedly attenuated in coronary resistance vessels in the remote myocardium after MI, which appears to serve as a compensatory mechanism to mitigate the loss of NO vasodilator influence.
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Affiliation(s)
- Daphne Merkus
- Experimental Cardiology, Thoraxcenter, Cardiovascular Research Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Marleen Visser
- Experimental Cardiology, Thoraxcenter, Cardiovascular Research Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Birgit Houweling
- Experimental Cardiology, Thoraxcenter, Cardiovascular Research Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Zhichao Zhou
- Experimental Cardiology, Thoraxcenter, Cardiovascular Research Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Jessica Nelson
- Experimental Cardiology, Thoraxcenter, Cardiovascular Research Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Dirk J. Duncker
- Experimental Cardiology, Thoraxcenter, Cardiovascular Research Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
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Marshall KD, Muller BN, Krenz M, Hanft LM, McDonald KS, Dellsperger KC, Emter CA. Heart failure with preserved ejection fraction: chronic low-intensity interval exercise training preserves myocardial O2 balance and diastolic function. J Appl Physiol (1985) 2013; 114:131-47. [PMID: 23104696 PMCID: PMC3544520 DOI: 10.1152/japplphysiol.01059.2012] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Accepted: 10/23/2012] [Indexed: 12/17/2022] Open
Abstract
We have previously reported chronic low-intensity interval exercise training attenuates fibrosis, impaired cardiac mitochondrial function, and coronary vascular dysfunction in miniature swine with left ventricular (LV) hypertrophy (Emter CA, Baines CP. Am J Physiol Heart Circ Physiol 299: H1348-H1356, 2010; Emter CA, et al. Am J Physiol Heart Circ Physiol 301: H1687-H1694, 2011). The purpose of this study was to test two hypotheses: 1) chronic low-intensity interval training preserves normal myocardial oxygen supply/demand balance; and 2) training-dependent attenuation of LV fibrotic remodeling improves diastolic function in aortic-banded sedentary, exercise-trained (HF-TR), and control sedentary male Yucatan miniature swine displaying symptoms of heart failure with preserved ejection fraction. Pressure-volume loops, coronary blood flow, and two-dimensional speckle tracking ultrasound were utilized in vivo under conditions of increasing peripheral mean arterial pressure and β-adrenergic stimulation 6 mo postsurgery to evaluate cardiac function. Normal diastolic function in HF-TR animals was characterized by prevention of increased time constant of isovolumic relaxation, normal LV untwisting rate, and enhanced apical circumferential and radial strain rate. Reduced fibrosis, normal matrix metalloproteinase-2 and tissue inhibitors of metalloproteinase-4 mRNA expression, and increased collagen III isoform mRNA levels (P < 0.05) accompanied improved diastolic function following chronic training. Exercise-dependent improvements in coronary blood flow for a given myocardial oxygen consumption (P < 0.05) and cardiac efficiency (stroke work to myocardial oxygen consumption, P < 0.05) were associated with preserved contractile reserve. LV hypertrophy in HF-TR animals was associated with increased activation of Akt and preservation of activated JNK/SAPK. In conclusion, chronic low-intensity interval exercise training attenuates diastolic impairment by promoting compliant extracellular matrix fibrotic components and preserving extracellular matrix regulatory mechanisms, preserves myocardial oxygen balance, and promotes a physiological molecular hypertrophic signaling phenotype in a large animal model resembling heart failure with preserved ejection fraction.
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Affiliation(s)
- Kurt D Marshall
- Department of Biomedical Science, University of Missouri-Columbia, Columbia, Missouri 65211, USA
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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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Taverne YJHJ, de Beer VJ, Hoogteijling BA, Juni RP, Moens AL, Duncker DJ, Merkus D. Nitroso-redox balance in control of coronary vasomotor tone. J Appl Physiol (1985) 2012; 112:1644-52. [PMID: 22362403 DOI: 10.1152/japplphysiol.00479.2011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Reactive oxygen species (ROS) are essential in vascular homeostasis but may contribute to vascular dysfunction when excessively produced. Superoxide anion (O(2)(·-)) can directly affect vascular tone by reacting with K(+) channels and indirectly by reacting with nitric oxide (NO), thereby scavenging NO and causing nitroso-redox imbalance. After myocardial infarction (MI), oxidative stress increases, favoring the imbalance and resulting in coronary vasoconstriction. Consequently, we hypothesized that ROS scavenging results in coronary vasodilation, particularly after MI, and is enhanced after inhibition of NO production. Chronically instrumented swine were studied at rest and during exercise before and after scavenging of ROS with N-(2-mercaptoproprionyl)-glycine (MPG, 20 mg/kg iv) in the presence or absence of prior inhibition of endothelial NO synthase (eNOS) with N(ω)-nitro-L-arginine (L-NNA, 20 mg/kg iv). In normal swine, MPG resulted in coronary vasodilation as evidenced by an increased coronary venous O(2) tension, and trends toward increased coronary venous O(2) saturation and decreased myocardial O(2) extraction. These effects were not altered by prior inhibition of eNOS. In MI swine, MPG showed a significant vasodilator effect, which surprisingly was abolished by prior inhibition of eNOS. Moreover, eNOS dimer/monomer ratio was decreased after MI, reflecting eNOS uncoupling. In conclusion, ROS exert a small coronary vasoconstrictor influence in normal swine, which does not involve scavenging of NO. This vasoconstrictor influence of ROS is slightly enhanced after MI. Since inhibition of eNOS abolished rather than augmented the vasoconstrictor influence of ROS in swine with MI, while eNOS dimer/monomer ratio was decreased, our data imply that uncoupled eNOS may be a significant source of O(2)(·-) after MI.
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Affiliation(s)
- Yannick J H J Taverne
- Experimental Cardiology, Thoraxcenter, Cardiovascular Research Institute COEUR, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
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