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Hartmann N, Preuß L, Mohamed BA, Schnelle M, Renner A, Hasenfuß G, Toischer K. Different activation of MAPKs and Akt/GSK3β after preload vs. afterload elevation. ESC Heart Fail 2022; 9:1823-1831. [PMID: 35315235 PMCID: PMC9065823 DOI: 10.1002/ehf2.13877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 02/07/2022] [Accepted: 02/28/2022] [Indexed: 11/28/2022] Open
Abstract
Aims Pressure overload (PO) and volume overload (VO) lead to concentric or eccentric hypertrophy. Previously, we could show that activation of signalling cascades differ in in vivo mouse models. Activation of these signal cascades could either be induced by intrinsic load sensing or neuro‐endocrine substances like catecholamines or the renin‐angiotensin‐aldosterone system. Methods and results We therefore analysed the activation of classical cardiac signal pathways [mitogen‐activated protein kinases (MAPKs) (ERK, p38, and JNK) and Akt‐GSK3β] in in vitro of mechanical overload (ejecting heart model, rabbit and human isolated muscle strips). Selective elevation of preload in vitro increased AKT and GSK3β phosphorylation after 15 min in isolated rabbit muscles strips (AKT 49%, GSK3β 26%, P < 0.05) and in mouse ejecting hearts (AKT 51%, GSK49%, P < 0.05), whereas phosphorylation of MAPKs was not influenced by increased preload. Selective elevation of afterload revealed an increase in ERK phosphorylation in the ejecting heart (43%, P < 0.05), but not in AKT, GSK3β, and the other MAPKs. Elevation of preload and afterload in the ejecting heart induced a significant phosphorylation of ERK (95%, P < 0.001) and showed a moderate increased AKT (P = 0.14) and GSK3β (P = 0.21) phosphorylation, which did not reach significance. Preload and afterload elevation in muscles strips from human failing hearts showed neither AKT nor ERK phosphorylation changes. Conclusions Our data show that preload activates the AKT–GSK3β and afterload the ERK pathway in vitro, indicating an intrinsic mechanism independent of endocrine signalling.
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Affiliation(s)
- Nico Hartmann
- Department of Cardiology and Pneumology, University Medical Center Göttingen, Robert-Koch-Str. 40, Göttingen, 37075, Germany
| | - Lena Preuß
- Department of Cardiology and Pneumology, University Medical Center Göttingen, Robert-Koch-Str. 40, Göttingen, 37075, Germany
| | - Belal A Mohamed
- Department of Cardiology and Pneumology, University Medical Center Göttingen, Robert-Koch-Str. 40, Göttingen, 37075, Germany.,DZHK, German Centre for Cardiovascular Research, Göttingen, Germany
| | - Moritz Schnelle
- Institute for Clinical Chemistry, University Medical Center Göttingen, Göttingen, Germany.,DZHK, German Centre for Cardiovascular Research, Göttingen, Germany
| | - Andre Renner
- Department of Thoracic, Cardiac and Vascular Surgery (Heart and Diabetes Center), North Rhine Westphalia, Bad Oeynhausen, Germany
| | - Gerd Hasenfuß
- Department of Cardiology and Pneumology, University Medical Center Göttingen, Robert-Koch-Str. 40, Göttingen, 37075, Germany.,DZHK, German Centre for Cardiovascular Research, Göttingen, Germany
| | - Karl Toischer
- Department of Cardiology and Pneumology, University Medical Center Göttingen, Robert-Koch-Str. 40, Göttingen, 37075, Germany.,DZHK, German Centre for Cardiovascular Research, Göttingen, Germany
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Zhang X, Liu ZQ, Singh D, Powell DK, Chung CS, Campbell KS, Wenk JF. Differential Effects of Isoproterenol on Regional Myocardial Mechanics in Rat using 3D cine DENSE Cardiovascular Magnetic Resonance. J Biomech Eng 2018; 141:2696750. [PMID: 30098173 DOI: 10.1115/1.4041042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Indexed: 01/03/2023]
Abstract
The present study assessed the acute effects of isoproterenol on left ventricular (LV) mechanics in healthy rats with the hypothesis that ß-adrenergic stimulation influences the mechanics of different myocardial regions of the LV wall in different ways. To accomplish this, magnetic resonance images were obtained in the LV of healthy rats with or without isoproterenol infusion. The LV contours were divided into basal, mid-ventricular, and apical regions. Additionally, the mid-ventricular myocardium was divided into three transmural layers with each layer partitioned into four segments (i.e., septal, inferior, lateral, and anterior). Peak systolic strains and torsion were quantified for each region. Isoproterenol significantly increased peak systolic radial strain and circumferential-longitudinal shear strain, as well as ventricular torsion, throughout the basal, mid-ventricle, and apical regions. In the mid-ventricle, isoproterenol significantly increased peak systolic radial strain, and induced significant increases in peak systolic circumferential strain and longitudinal strain in the septum. Isoproterenol consistently increased peak systolic circumferential-longitudinal shear strain in all mid-ventricular segments. Ventricular torsion was significantly increased in nearly all segments except the inferior sub-endocardium. The effects of isoproterenol on LV systolic mechanics (i.e., 3D strains and torsion) in healthy rats depend on the region. This region-dependency is also strain component-specific. These results provide insight into the regional response of LV mechanics to ß-adrenergic stimulation in rats, and could act as a baseline for future studies on subclinical abnormalities associated with the inotropic response in heart disease.
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Affiliation(s)
- Xiaoyan Zhang
- Department of Mechanical Engineering, University of Kentucky, Lexington, KY, USA
| | - Zhan-Qiu Liu
- Department of Mechanical Engineering, University of Kentucky, Lexington, KY, USA
| | - Dara Singh
- Department of Mechanical Engineering, University of Kentucky, Lexington, KY, USA
| | - David K Powell
- Department of Anatomy and Neurobiology, University of Kentucky, Lexington, KY, USA
| | - Charles S Chung
- Department of Physiology, Wayne State University, Detroit, MI, USA; Department of Physiology, University of Kentucky, Lexington, KY, USA
| | | | - Jonathan F Wenk
- Department of Surgery, University of Kentucky, Lexington, KY, USA
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Bakkehaug JP, Naesheim T, Torgersen Engstad E, Kildal AB, Myrmel T, How OJ. Reversing dobutamine-induced tachycardia using ivabradine increases stroke volume with neutral effect on cardiac energetics in left ventricular post-ischaemia dysfunction. Acta Physiol (Oxf) 2016; 218:78-88. [PMID: 27145482 DOI: 10.1111/apha.12704] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 04/03/2016] [Accepted: 05/02/2016] [Indexed: 12/01/2022]
Abstract
AIM Compensatory tachycardia can potentially be deleterious in acute heart failure. In this study, we tested a therapeutic strategy of combined inotropic support (dobutamine) and selective heart rate (HR) reduction through administration of ivabradine. METHODS In an open-chest pig model (n = 12) with left ventricular (LV) post-ischaemia dysfunction, cardiac function was assessed by LV pressure catheter and sonometric crystals. Coronary flow and blood samples from the coronary sinus were used to measure myocardial oxygen consumption (MVO2 ). LV energetics was assessed by comparing MVO2 with cardiac work at a wide range of workloads. RESULTS In the post-ischaemia heart, dobutamine (5 μg kg(-1) min(-1) ) increased cardiac output (CO) by increasing HR from 102 ± 21 to 131 ± 16 bpm (beats per min; P < 0.05). Adding ivabradine (0.5 mg kg(-1) ) slowed HR back to 100 ± 9 bpm and increased stroke volume from 30 ± 5 to 36 ± 5 mL (P < 0.05) by prolonging diastolic filling time and increasing end-diastolic dimensions. Adding ivabradine had no adverse effects on CO, mean arterial pressure and cardiac efficiency. Similar findings on efficiency and LV function were also seen using an ex vivo working mouse heart protocol. CONCLUSIONS A combined infusion of dobutamine and ivabradine had a neutral effect on post-ischaemia LV efficiency and increased left ventricular output without an increase in HR.
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Affiliation(s)
- J. P. Bakkehaug
- Cardiovascular Research Group; Institute of Medical Biology; Faculty of Health Sciences; UiT; The Arctic University of Norway; Tromsø Norway
| | - T. Naesheim
- Institute of Clinical Medicine; Faculty of Health Sciences; UiT; The Arctic University of Norway; Tromsø Norway
| | - E. Torgersen Engstad
- Cardiovascular Research Group; Institute of Medical Biology; Faculty of Health Sciences; UiT; The Arctic University of Norway; Tromsø Norway
| | - A. B. Kildal
- Cardiovascular Research Group; Institute of Medical Biology; Faculty of Health Sciences; UiT; The Arctic University of Norway; Tromsø Norway
| | - T. Myrmel
- Institute of Clinical Medicine; Faculty of Health Sciences; UiT; The Arctic University of Norway; Tromsø Norway
- Department of Cardiothoracic and Vascular Surgery; Heart and Lung Clinic; University Hospital of North Norway; Tromsø Norway
| | - O.-J. How
- Cardiovascular Research Group; Institute of Medical Biology; Faculty of Health Sciences; UiT; The Arctic University of Norway; Tromsø Norway
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Park J, Kim YA, Han JY, Jin S, Ok SH, Sohn JT, Lee HK, Chung YK, Shin IW. Lipofundin® MCT/LCT 20% increase left ventricular systolic pressure in an ex vivo rat heart model via increase of intracellular calcium level. Korean J Anesthesiol 2016; 69:57-62. [PMID: 26885303 PMCID: PMC4754268 DOI: 10.4097/kjae.2016.69.1.57] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 11/19/2015] [Accepted: 11/19/2015] [Indexed: 02/07/2023] Open
Abstract
Background Lipid emulsions have been used to treat various drug toxicities and for total parenteral nutrition therapy. Their usefulness has also been confirmed in patients with local anesthetic-induced cardiac toxicity. The purpose of this study was to measure the hemodynamic and composition effects of lipid emulsions and to elucidate the mechanism associated with changes in intracellular calcium levels in myocardiocytes. Methods We measured hemodynamic effects using a digital analysis system after Intralipid® and Lipofundin® MCT/LCT were infused into hearts hanging in a Langendorff perfusion system. We measured the effects of the lipid emulsions on intracellular calcium levels in H9c2 cells by confocal microscopy. Results Infusion of Lipofundin® MCT/LCT 20% (1 ml/kg) resulted in a significant increase in left ventricular systolic pressure compared to that after infusing modified Krebs-Henseleit solution (1 ml/kg) (P = 0.003, 95% confidence interval [CI], 2.4–12.5). Lipofundin® MCT/LCT 20% had a more positive inotropic effect than that of Intralipid® 20% (P = 0.009, 95% CI, 1.4–11.6). Both lipid emulsion treatments increased intracellular calcium levels. Lipofundin® MCT/LCT (0.01%) increased intracellular calcium level more than that of 0.01% Intralipid® (P < 0.05, 95% CI, 0.0–1.9). Conclusions These two lipid emulsions had different inotropic effects depending on their triglyceride component. The inotropic effect of lipid emulsions could be related with intracellular calcium level.
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Affiliation(s)
- Jiyoung Park
- Department of Anesthesiology and Pain Medicine, Gyeongsang National University Hospital, Jinju, Korea
| | - Yeon A Kim
- Department of Anatomy and Cell biology, Dong-A University College of Medicine and Mitochondria Hub Regulation Center, Busan, Korea
| | - Jeong Yeol Han
- Department of Anesthesiology and Pain Medicine, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Sangkyu Jin
- Department of Anesthesiology and Pain Medicine, Gyeongsang National University Hospital, Jinju, Korea
| | - Seong-Ho Ok
- Department of Anesthesiology and Pain Medicine, Gyeongsang National University Hospital, Jinju, Korea.; Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju, Korea
| | - Ju-Tae Sohn
- Department of Anesthesiology and Pain Medicine, Gyeongsang National University Hospital, Jinju, Korea.; Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju, Korea
| | - Heon-Keun Lee
- Department of Anesthesiology and Pain Medicine, Gyeongsang National University Hospital, Jinju, Korea.; Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju, Korea
| | - Young-Kyun Chung
- Department of Anesthesiology and Pain Medicine, Gyeongsang National University Hospital, Jinju, Korea.; Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju, Korea
| | - Il-Woo Shin
- Department of Anesthesiology and Pain Medicine, Gyeongsang National University Hospital, Jinju, Korea.; Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju, Korea
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Isolated heart models: cardiovascular system studies and technological advances. Med Biol Eng Comput 2015; 53:669-78. [DOI: 10.1007/s11517-015-1270-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 03/02/2015] [Indexed: 01/27/2023]
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Drenjancevic I, Koller A, Selthofer-Relatic K, Grizelj I, Cavka A. Assessment of coronary hemodynamics and vascular function. Prog Cardiovasc Dis 2014; 57:423-30. [PMID: 25460847 DOI: 10.1016/j.pcad.2014.11.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Coronary blood flow closely matches to metabolic demands of heart and myocardial oxygen consumption and is conditioned by function of coronary resistance vessels. The microvascular endothelium of coronary resistance vessels is exposed to a spatially and temporally regulated input from cardiomyocytes and the haemodynamic forces of the cardiac cycle. Functional measurements of coronary pressure and flow are important approaches that provide complementary information on the function of coronary vessel function that could not be assessed by the methods utilized for the anatomic characterization of coronary disease, such as coronary angiography. The goal of this paper is to review the methodologies for assessment of coronary vascular function and haemodynamics which are utilized in research and to discuss their potential applicability in the clinical settings.
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Affiliation(s)
- Ines Drenjancevic
- Faculty of Medicine Osijek, University of Osijek, Department of Physiology and Immunology, Osijek, Croatia.
| | - Akos Koller
- Department of Physiology and Gerontology, Medical School and Szentagothai Research Centre, University of Pecs, Hungary, Department of Pathophysiology, Semmelweis University, Budapest, Hungary, Department of Physiology New York Medical College, Valhalla NY 10595, USA; Walhala University NW, USA
| | - Kristina Selthofer-Relatic
- Faculty of Medicine Osijek, University of Osijek, Dept of Internal Medicine, Osijek, Croatia; Clinical Hospital Center Osijek, Clinic for Internal Diseases, Osijek, Croatia
| | - Ivana Grizelj
- Faculty of Medicine Osijek, University of Osijek, Department of Physiology and Immunology, Osijek, Croatia
| | - Ana Cavka
- Faculty of Medicine Osijek, University of Osijek, Department of Physiology and Immunology, Osijek, Croatia
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Liao R, Podesser BK, Lim CC. The continuing evolution of the Langendorff and ejecting murine heart: new advances in cardiac phenotyping. Am J Physiol Heart Circ Physiol 2012; 303:H156-67. [PMID: 22636675 DOI: 10.1152/ajpheart.00333.2012] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The isolated retrograde-perfused Langendorff heart and the isolated ejecting heart have, over many decades, resulted in fundamental discoveries that form the underpinnings of our current understanding of the biology and physiology of the heart. These two experimental methodologies have proven invaluable in studying pharmacological effects on myocardial function, metabolism, and vascular reactivity and in the investigation of clinically relevant disease states such as ischemia-reperfusion injury, diabetes, obesity, and heart failure. With the advent of the genomics era, the isolated mouse heart preparation has gained prominence as an ex vivo research tool for investigators studying the impact of gene modification in the intact heart. This review summarizes the historical development of the isolated heart and provides a practical guide for the establishment of the Langendorff and ejecting heart preparations with a particular emphasis on the murine heart. In addition, current applications and novel methods of recording cardiovascular parameters in the isolated heart preparation will be discussed. With continued advances in methodological recordings, the isolated mouse heart preparation will remain physiologically relevant for the foreseeable future, serving as an integral bridge between in vitro assays and in vivo approaches.
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Affiliation(s)
- Ronglih Liao
- Cardiac Muscle Research Laboratory, Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
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Kelly A, Elliott EB, Matsuda R, Kaneko N, Smith GL, Loughrey CM. The effect of K201 on isolated working rabbit heart mechanical function during pharmacologically induced Ca2+ overload. Br J Pharmacol 2012; 165:1068-83. [PMID: 21658026 DOI: 10.1111/j.1476-5381.2011.01531.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND AND PURPOSE Reduced cardiac contractility has been associated with disrupted myocardial Ca(2+) signalling. The 1,4 benzothiazepine K201 (JTV-519) acts on several Ca(2+) handling proteins and improves cardiac contractility in vivo in a variety of animal models of myocardial dysfunction. However, it is unclear whether this improvement depends on the systemic effects of K201 or if K201 reverses the effects of Ca(2+) dysregulation, regardless of the cause. EXPERIMENTAL APPROACH The effect of K201 on cardiac mechanical function was assessed in isolated working hearts from adult rabbits, using a ventricular pressure-volume catheter. In separate experiments, the effect of K201 was investigated in hearts following pharmacologically induced Ca(2+) overload using elevated extracellular [Ca(2+) ] ([Ca(2+) ](o) ) and β-adrenoceptor stimulation. KEY RESULTS K201 induced a concentration-dependent decline in systolic function (peak pressure, dP/dt(max) and preload recruitable stroke work), lusitropy (reduced dP/dt(min) and increased end diastolic pressure) and stroke volume, independent of decreased heart rate. In separate experiments, mechanical function in hearts exposed to 4.5 mmol·L(-1) [Ca(2+) ](o) and 150 nmol·L(-1) isoprenaline declined until cessation of aortic flow (in 6 out of 11 hearts). However, all hearts perfused with the addition of 1 µmol·L(-1) K201 maintained aortic flow and demonstrated significantly improved peak systolic pressures, dP/dt(max) and dP/dt(min) . CONCLUSIONS AND IMPLICATIONS K201 significantly improved mechanical function of the heart during Ca(2+) overload. This suggests that K201 can limit the detrimental effects of elevated intracellular Ca(2+) and exert beneficial effects on cardiac contractile function, independent of systemic effects previously observed in vivo.
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Affiliation(s)
- A Kelly
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, Glasgow, UK
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Reil JC, Hohl M, Oberhofer M, Kazakov A, Kaestner L, Mueller P, Adam O, Maack C, Lipp P, Mewis C, Allessie M, Laufs U, Böhm M, Neuberger HR. Cardiac Rac1 overexpression in mice creates a substrate for atrial arrhythmias characterized by structural remodelling. Cardiovasc Res 2010; 87:485-93. [PMID: 20211865 DOI: 10.1093/cvr/cvq079] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AIMS The small GTPase Rac1 seems to play a role in the pathogenesis of atrial fibrillation (AF). The aim of the present study was to characterize the effects of Rac1 overexpression on atrial electrophysiology. METHODS AND RESULTS In mice with cardiac overexpression of constitutively active Rac1 (RacET), statin-treated RacET, and wild-type controls (age 6 months), conduction in the right and left atrium (RA and LA) was mapped epicardially. The atrial effective refractory period (AERP) was determined and inducibility of atrial arrhythmias was tested. Action potentials were recorded in isolated cells. Left ventricular function was measured by pressure-volume analysis. Five of 11 RacET hearts showed spontaneous or inducible atrial tachyarrhythmias vs. 0 of 9 controls (P < 0.05). In RacET, the P-wave duration was significantly longer (26.8 +/- 2.1 vs. 16.7 +/- 1.1 ms, P = 0.001) as was total atrial activation time (RA: 13.6 +/- 4.4 vs. 3.2 +/- 0.5 ms; LA: 7.1 +/- 1.2 vs. 2.2 +/- 0.3 ms, P < 0.01). Prolonged local conduction times occurred more often in RacET (RA: 24.4 +/- 3.8 vs. 2.7 +/- 2.1%; LA: 19.1 +/- 6.3 vs. 1.2 +/- 0.7%, P < 0.01). The AERP and action potential duration did not differ significantly between both groups. RacET demonstrated significant atrial fibrosis but only moderate systolic heart failure. RacET and statin-treated RacET were not significantly different regarding atrial electrophysiology. CONCLUSION The substrate for atrial arrhythmias in mice with Rac1 overexpression is characterized by conduction disturbances and atrial fibrosis. Electrical remodelling (i.e. a shortening of AERP) does not play a role. Statin treatment cannot prevent the structural and electrophysiological effects of pronounced Rac1 overexpression in this model.
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Affiliation(s)
- Jan-Christian Reil
- Klinik für Innere Medizin III (Kardiologie, Angiologie, Internistische Intensivmedizin), Universitätsklinikum des Saarlandes, Kirrberger Strasse, Homburg/Saar D 66421, Germany.
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Shioura KM, Geenen DL, Goldspink PH. Assessment of cardiac function with the pressure-volume conductance system following myocardial infarction in mice. Am J Physiol Heart Circ Physiol 2007; 293:H2870-7. [PMID: 17720769 DOI: 10.1152/ajpheart.00585.2007] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Myocardial infarction (MI) is a major cause of heart failure (HF) with the progressive worsening of cardiac performance due to structural and functional alterations. Therefore, we studied cardiac function in adult mice following MI using the Millar pressure-volume (P-V) conductance catheter system in vivo during the later phase of compensatory remodeling and decompensation to HF. We evaluated load-dependent and -independent parameters in control and 2-, 4-, 6-, and 10-wk post-MI mice and integrated changes in function with changes in gene expression. Our results indicated a significant deterioration of cardiac function in post-MI mice over time, reflected first by systolic dysfunction, followed by a transient improvement before further decline in both systolic and diastolic function. Associated with the function and adaptive remodeling were transient changes in fetal gene and extracellular matrix gene expression. However, undermining the compensatory remodeling response was a continual decline in cardiac contractility, which promoted the transition into failure. Our study provided a scheme of integrated cardiac function and gene expression changes occurring during the adaptive and maladaptive response of the heart independent of systemic vascular properties during the transition to HF following MI in mice. P-V loop analysis was used to quantitatively evaluate the gradual deterioration in cardiac function post-MI. P-V loop analysis was found to be an appropriate method for assessment of global cardiac function under varying load-dependent and -independent conditions in the murine model with many similarities to data obtained from larger animals and humans.
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Affiliation(s)
- Krystyna M Shioura
- The Center for Cardiovascular Research, Department of Medicine, Section of Cardiology, University of Illinois at Chicago, Chicago, IL 60612, USA
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Klotz S, Dickstein ML, Burkhoff D. A computational method of prediction of the end-diastolic pressure–volume relationship by single beat. Nat Protoc 2007; 2:2152-8. [PMID: 17853871 DOI: 10.1038/nprot.2007.270] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The end-diastolic pressure-volume relation (EDPVR) is an important descriptor of passive cardiac pump properties. However, clinical utility has been limited by the need for measurement of pressures and volumes over relatively large ranges. In this protocol, we describe an algorithm to estimate the entire EDPVR in humans from a single measured pressure-volume (P-V) point. This algorithm was developed from observations made from accurately measured EDPVRs of human hearts, which indicated that when normalized by appropriate left ventricular volume scaling (to arrive at volume-normalized EDPVRs, EDPVR(n)) EDPVR(n)s were nearly identical in all patients. In this protocol, we demonstrate how to use EDPVR(n)s to predict a second P-V point on the EDPVR, in which case the entire EDPVR can then be predicted. With recent advances for accurate noninvasive measurement of end-diastolic pressure and volumes, this protocol permits the assessment of passive properties in a broader range of research and clinical settings.
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Affiliation(s)
- Stefan Klotz
- Department of Thoracic and Cardiovascular Surgery, University Hospital, Muenster, Germany.
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How OJ, Aasum E, Larsen TS. Work-independent assessment of efficiency in ex vivo working rodent hearts within the PVA-MVO2 framework. Acta Physiol (Oxf) 2007; 190:171-5. [PMID: 17394570 DOI: 10.1111/j.1748-1716.2007.01681.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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13
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Grieve DJ, Byrne JA, Siva A, Layland J, Johar S, Cave AC, Shah AM. Involvement of the Nicotinamide Adenosine Dinucleotide Phosphate Oxidase Isoform Nox2 in Cardiac Contractile Dysfunction Occurring in Response to Pressure Overload. J Am Coll Cardiol 2006; 47:817-26. [PMID: 16487851 DOI: 10.1016/j.jacc.2005.09.051] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/01/2005] [Revised: 09/14/2005] [Accepted: 09/19/2005] [Indexed: 10/25/2022]
Abstract
OBJECTIVES This study sought to examine the role of Nox2 in the contractile dysfunction associated with pressure-overload left ventricular hypertrophy (LVH). BACKGROUND Reactive oxygen species (ROS) production is implicated in the pathophysiology of LVH. The nicotinamide adenosine dinucleotide phosphate oxidase isoform, Nox2, is pivotally involved in angiotensin II-induced hypertrophy but is not essential for development of pressure-overload LVH. Its possible impact on contractile function is unknown. METHODS The effects of aortic banding or sham surgery on cardiac contractile function and interstitial fibrosis were compared in adult Nox2-/- and matched wild-type (WT) mice. RESULTS Banding induced similar increases in left ventricular (LV) mass in both groups. Banded Nox2-/- mice had better LV function than WT by echocardiography (e.g., fractional shortening 33.6 +/- 2.5% vs. 21.4 +/- 2.2%, p < 0.05). Comprehensive LV pressure-volume analyses also showed significant contractile dysfunction in banded WT compared with sham, whereas banded Nox2-/- mice had preserved function (e.g., maximum rate of rise of LV pressure: banded WT, 4,879 +/- 213; vs. banded Nox2-/-, 5,913 +/- 259 mm Hg/s; p < 0.05). Similar preservation of function was observed in isolated cardiomyocytes. The 24-h to 36-h treatment of banded WT mice with N-acetylcysteine resulted in recovery of contractile function. Cardiac interstitial fibrosis was significantly increased in banded WT but not Nox2-/- mice, together with greater increases in procollagen I and III mRNA expression. CONCLUSIONS The Nox2 oxidase contributes to the development of cardiac contractile dysfunction and interstitial fibrosis during pressure overload, although it is not essential for development of morphologic hypertrophy per se. These data suggest divergent downstream effects of Nox2 on different components of the overall response to pressure overload.
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Affiliation(s)
- David J Grieve
- King's College London, Cardiovascular Division, Guy's, King's, and St. Thomas' School of Medicine, London, England
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Fukuda N, Wu Y, Nair P, Granzier HL. Phosphorylation of titin modulates passive stiffness of cardiac muscle in a titin isoform-dependent manner. ACTA ACUST UNITED AC 2005; 125:257-71. [PMID: 15738048 PMCID: PMC2234012 DOI: 10.1085/jgp.200409177] [Citation(s) in RCA: 151] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We investigated the effect of protein kinase A (PKA) on passive force in skinned cardiac tissues that express different isoforms of titin, i.e., stiff (N2B) and more compliant (N2BA) titins, at different levels. We used rat ventricular (RV), bovine left ventricular (BLV), and bovine left atrial (BLA) muscles (passive force: RV > BLV > BLA, with the ratio of N2B to N2BA titin, ∼90:10, ∼40:60, and ∼10:90%, respectively) and found that N2B and N2BA isoforms can both be phosphorylated by PKA. Under the relaxed condition, sarcomere length was increased and then held constant for 30 min and the peak passive force, stress-relaxation, and steady-state passive force were determined. Following PKA treatment, passive force was significantly decreased in all muscle types with the effect greatest in RV, lowest in BLA, and intermediate in BLV. Fitting the stress-relaxation data to the sum of three exponential decay functions revealed that PKA blunts the magnitude of stress-relaxation and accelerates its time constants. To investigate whether or not PKA-induced decreases in passive force result from possible alteration of titin–thin filament interaction (e.g., via troponin I phosphorylation), we conducted the same experiments using RV preparations that had been treated with gelsolin to extract thin filaments. PKA decreased passive force in gelsolin-treated RV preparations with a magnitude similar to that observed in control preparations. PKA was also found to decrease restoring force in skinned ventricular myocytes of the rat that had been shortened to below the slack length. Finally, we investigated the effect of the β-adrenergic receptor agonist isoprenaline on diastolic force in intact rat ventricular trabeculae. We found that isoprenaline phosphorylated titin and that it reduced diastolic force to a degree similar to that found in skinned RV preparations. Taken together, these results suggest that during β-adrenergic stimulation, PKA increases ventricular compliance in a titin isoform-dependent manner.
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Affiliation(s)
- Norio Fukuda
- Department of Veterinary and Comparative Anatomy, Pharmacology and Physiology, Washington State University, Pullman, WA 99164, USA
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How OJ, Aasum E, Kunnathu S, Severson DL, Myhre ESP, Larsen TS. Influence of substrate supply on cardiac efficiency, as measured by pressure-volume analysis in ex vivo mouse hearts. Am J Physiol Heart Circ Physiol 2005; 288:H2979-85. [PMID: 15764683 DOI: 10.1152/ajpheart.00084.2005] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In the present study, we tested the reliability of measurements of pressure-volume area (PVA) and oxygen consumption (MV̇o2) in ex vivo mouse hearts, combining the use of a miniaturized conductance catheter and a fiber-optic oxygen sensor. Second, we tested whether we could reproduce the influence of increased myocardial fatty acid (FA) metabolism on cardiac efficiency in the isolated working mouse heart model, which has already been documented in large animal models. The hearts were perfused with crystalloid buffer containing 11 mM glucose and two different concentrations of FA bound to 3% BSA. The initial concentration was 0.3 ± 0.1 mM, which was subsequently raised to 0.9 ± 0.1 mM. End-systolic and end-diastolic pressure-volume relationships were assessed by temporarily occluding the preload line. Different steady-state PVA-MV̇o2relationships were obtained by changing the loading conditions (pre- and afterload) of the heart. There were no apparent changes in baseline cardiac performance or contractile efficiency (slope of the PVA-MV̇o2regression line) in response to the elevation of the perfusate FA concentration. However, all hearts ( n = 8) showed an increase in the y-intercept of the PVA-MV̇o2regression line after elevation of the palmitate concentration, indicating an FA-induced increase in the unloaded MV̇o2. Therefore, in the present model, unloaded MV̇o2is not independent of metabolic substrate. This is, to our knowledge, the first report of a PVA-MV̇o2relationship in ex vivo perfused murine hearts, using a pressure-volume catheter. The methodology can be an important tool for phenotypic assessment of the relationship among metabolism, contractile performance, and cardiac efficiency in various mouse models.
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Affiliation(s)
- Ole-Jakob How
- Dept. of Medical Physiology, Institute of Medical Biology, Faculty of Medicine, Univ. of Tromsø, Tromsø N-9037 Norway.
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