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Antoniou CK, Manolakou P, Magkas N, Konstantinou K, Chrysohoou C, Dilaveris P, Gatzoulis KA, Tousoulis D. Cardiac Resynchronisation Therapy and Cellular Bioenergetics: Effects Beyond Chamber Mechanics. Eur Cardiol 2019; 14:33-44. [PMID: 31131035 PMCID: PMC6523053 DOI: 10.15420/ecr.2019.2.2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Cardiac resynchronisation therapy is a cornerstone in the treatment of advanced dyssynchronous heart failure. However, despite its widespread clinical application, precise mechanisms through which it exerts its beneficial effects remain elusive. Several studies have pointed to a metabolic component suggesting that, both in concert with alterations in chamber mechanics and independently of them, resynchronisation reverses detrimental changes to cellular metabolism, increasing energy efficiency and metabolic reserve. These actions could partially account for the existence of responders that improve functionally but not echocardiographically. This article will attempt to summarise key components of cardiomyocyte metabolism in health and heart failure, with a focus on the dyssynchronous variant. Both chamber mechanics-related and -unrelated pathways of resynchronisation effects on bioenergetics – stemming from the ultramicroscopic level – and a possible common underlying mechanism relating mechanosensing to metabolism through the cytoskeleton will be presented. Improved insights regarding the cellular and molecular effects of resynchronisation on bioenergetics will promote our understanding of non-response, optimal device programming and lead to better patient care.
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Affiliation(s)
| | - Panagiota Manolakou
- First Department of Cardiology, School of Medicine, National and Kapodistrian University of Athens Athens, Greece
| | - Nikolaos Magkas
- First Department of Cardiology, School of Medicine, National and Kapodistrian University of Athens Athens, Greece
| | - Konstantinos Konstantinou
- First Department of Cardiology, School of Medicine, National and Kapodistrian University of Athens Athens, Greece
| | - Christina Chrysohoou
- First Department of Cardiology, School of Medicine, National and Kapodistrian University of Athens Athens, Greece
| | - Polychronis Dilaveris
- First Department of Cardiology, School of Medicine, National and Kapodistrian University of Athens Athens, Greece
| | - Konstantinos A Gatzoulis
- First Department of Cardiology, School of Medicine, National and Kapodistrian University of Athens Athens, Greece
| | - Dimitrios Tousoulis
- First Department of Cardiology, School of Medicine, National and Kapodistrian University of Athens Athens, Greece
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Liu T, Takimoto E, Dimaano VL, DeMazumder D, Kettlewell S, Smith G, Sidor A, Abraham TP, O'Rourke B. Inhibiting mitochondrial Na+/Ca2+ exchange prevents sudden death in a Guinea pig model of heart failure. Circ Res 2014; 115:44-54. [PMID: 24780171 DOI: 10.1161/circresaha.115.303062] [Citation(s) in RCA: 137] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
RATIONALE In cardiomyocytes from failing hearts, insufficient mitochondrial Ca(2+) accumulation secondary to cytoplasmic Na(+) overload decreases NAD(P)H/NAD(P)(+) redox potential and increases oxidative stress when workload increases. These effects are abolished by enhancing mitochondrial Ca(2+) with acute treatment with CGP-37157 (CGP), an inhibitor of the mitochondrial Na(+)/Ca(2+) exchanger. OBJECTIVE Our aim was to determine whether chronic CGP treatment mitigates contractile dysfunction and arrhythmias in an animal model of heart failure (HF) and sudden cardiac death (SCD). METHODS AND RESULTS Here, we describe a novel guinea pig HF/SCD model using aortic constriction combined with daily β-adrenergic receptor stimulation (ACi) and show that chronic CGP treatment (ACi plus CGP) attenuates cardiac hypertrophic remodeling, pulmonary edema, and interstitial fibrosis and prevents cardiac dysfunction and SCD. In the ACi group 4 weeks after pressure overload, fractional shortening and the rate of left ventricular pressure development decreased by 36% and 32%, respectively, compared with sham-operated controls; in contrast, cardiac function was completely preserved in the ACi plus CGP group. CGP treatment also significantly reduced the incidence of premature ventricular beats and prevented fatal episodes of ventricular fibrillation, but did not prevent QT prolongation. Without CGP treatment, mortality was 61% in the ACi group <4 weeks of aortic constriction, whereas the death rate in the ACi plus CGP group was not different from sham-operated animals. CONCLUSIONS The findings demonstrate the critical role played by altered mitochondrial Ca(2+) dynamics in the development of HF and HF-associated SCD; moreover, they reveal a novel strategy for treating SCD and cardiac decompensation in HF.
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Affiliation(s)
- Ting Liu
- From the Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD (T.L., E.T., V.L.D., D.D., A.S., T.P.A., B.O.'R.); and Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom (S.K., G.S.)
| | - Eiki Takimoto
- From the Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD (T.L., E.T., V.L.D., D.D., A.S., T.P.A., B.O.'R.); and Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom (S.K., G.S.)
| | - Veronica L Dimaano
- From the Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD (T.L., E.T., V.L.D., D.D., A.S., T.P.A., B.O.'R.); and Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom (S.K., G.S.)
| | - Deeptankar DeMazumder
- From the Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD (T.L., E.T., V.L.D., D.D., A.S., T.P.A., B.O.'R.); and Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom (S.K., G.S.)
| | - Sarah Kettlewell
- From the Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD (T.L., E.T., V.L.D., D.D., A.S., T.P.A., B.O.'R.); and Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom (S.K., G.S.)
| | - Godfrey Smith
- From the Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD (T.L., E.T., V.L.D., D.D., A.S., T.P.A., B.O.'R.); and Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom (S.K., G.S.)
| | - Agnieszka Sidor
- From the Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD (T.L., E.T., V.L.D., D.D., A.S., T.P.A., B.O.'R.); and Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom (S.K., G.S.)
| | - Theodore P Abraham
- From the Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD (T.L., E.T., V.L.D., D.D., A.S., T.P.A., B.O.'R.); and Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom (S.K., G.S.)
| | - Brian O'Rourke
- From the Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD (T.L., E.T., V.L.D., D.D., A.S., T.P.A., B.O.'R.); and Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom (S.K., G.S.).
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O'Rourke B, Van Eyk JE, Foster DB. Mitochondrial protein phosphorylation as a regulatory modality: implications for mitochondrial dysfunction in heart failure. CONGESTIVE HEART FAILURE (GREENWICH, CONN.) 2011; 17:269-82. [PMID: 22103918 PMCID: PMC4067253 DOI: 10.1111/j.1751-7133.2011.00266.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Phosphorylation of mitochondrial proteins has been recognized for decades, and the regulation of pyruvate- and branched-chain α-ketoacid dehydrogenases by an atypical kinase/phosphatase cascade is well established. More recently, the development of new mass spectrometry-based technologies has led to the discovery of many novel phosphorylation sites on a variety of mitochondrial targets. The evidence suggests that the major classes of kinase and several phosphatases may be present at the mitochondrial outer membrane, intermembrane space, inner membrane, and matrix, but many questions remain to be answered as to the location, timing, and reversibility of these phosphorylation events and whether they are functionally relevant. The authors review phosphorylation as a mitochondrial regulatory strategy and highlight its possible role in the pathophysiology of cardiac hypertrophy and failure.
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Affiliation(s)
- Brian O'Rourke
- Department of Medicine, Division of Cardiology, The Johns Hopkins University, Baltimore, MD 21205-2195, USA.
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Abstract
The standard treatment for acute heart failure (synonymous with pulmonary edema) is an upright posture, oxygen, morphine (often accompanied by an antiemetic), and intravenous diuretics. This treatment has remained unchanged for many years, and the precise mechanism by which each of these methods alleviates symptoms in patients is unclear. Nitrates, oral or intravenous, are also used with benefit, and have some hemodynamic advantages over intravenous diuretics. Recently, three new forms of treatment have been investigated. The use of milrinone, a phosphodiesterase inhibitor, for exacerbation of heart failure in patients with a background of chronic heart failure was not advantageous. The trials of levosimendan, a calcium sensitizer, in patients with pulmonary edema hinted at benefit. Nesiritide, a formulation of brain natriuretic peptide, does bring about hemodynamic improvement in acute heart failure, and is at least as effective as nitroglycerin, easier to prescribe, but prone to cause hypotension. These are small but important advances that increase our knowledge of the pathophysiology of acute heart failure, and also provide an indication of which drugs are preferable for the treatment of this distressing condition.
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Affiliation(s)
- Philip A Poole-Wilson
- Department of Cardiac Medicine, National Heart & Lung Institute, Dovehouse Street, London SW3 6LY, UK.
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Nelson GS, Berger RD, Fetics BJ, Talbot M, Spinelli JC, Hare JM, Kass DA. Left ventricular or biventricular pacing improves cardiac function at diminished energy cost in patients with dilated cardiomyopathy and left bundle-branch block. Circulation 2000; 102:3053-9. [PMID: 11120694 DOI: 10.1161/01.cir.102.25.3053] [Citation(s) in RCA: 494] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Left ventricular or biventricular pacing/stimulation can acutely improve systolic function in patients with dilated cardiomyopathy (DCM) and intraventricular conduction delay by resynchronizing contraction. Most heart failure therapies directly enhancing systolic function do so while concomitantly increasing myocardial oxygen consumption (MVO(2)). We hypothesized that pacing/stimulation, in contrast, incurs systolic benefits without raising energy demand. METHODS AND RESULTS Ten DCM patients with left bundle-branch block (ejection fraction 20+/-3%, QRS duration 179+/-3 ms, mean+/-SEM) underwent cardiac catheterization to measure ventricular and aortic pressure, coronary blood flow, arterial-coronary sinus oxygen difference (DeltaAVO(2)), and MVO(2). Data were measured under sinus rhythm or with left ventricular or biventricular pacing/stimulation at the same heart rate. These results were then contrasted to intravenous dobutamine (n=7) titrated to match systolic changes during LV pacing. Systolic function rose quickly and substantially from LV pacing (18+/-4% rise in arterial pulse pressure, which correlates with cardiac output, and 43+/-6% increase in dP/dt(max); both P<0.01). However, DeltaAVO(2) and MVO(2) declined -4+/-2% and -8+/-6.5%, respectively (both P<0.05). Similar results were obtained with biventricular activation. In contrast, dobutamine raised dP/dt(max) 37+/-6%, accompanied by a 22+/-11% rise in per-beat MVO(2) (P<0.05 versus pacing). CONCLUSIONS Ventricular resynchronization by left ventricular or biventricular pacing/stimulation in DCM patients with left bundle-branch block acutely enhances systolic function while modestly lowering energy cost. This should prove valuable for treating DCM patients with basal dyssynchrony.
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Affiliation(s)
- G S Nelson
- Division of Cardiology, Department of Medicine, The Johns Hopkins Medical Institutions, Baltimore, MD, USA
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Ruf T, Schulte-Baukloh H, Lüdemann J, Posival H, Beyersdorf F, Just H, Holubarsch C. Alterations of cross-bridge kinetics in human atrial and ventricular myocardium. Cardiovasc Res 1998; 40:580-90. [PMID: 10070500 DOI: 10.1016/s0008-6363(98)00164-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
CONDENSED ABSTRACT We analyzed actomyosin cross-bridge kinetics in human atrial and ventricular muscle strip preparations by using sinusoidal length changes from 0.1 to 60 Hz. The minimum stiffness frequency was higher in atrial than in ventricular human myocardium and lower in failing than in non-failing left ventricular human myocardium. beta-Adrenergic stimulation increased the minimum stiffness frequency by 18 +/- 3% (p < 0.05). Cross-bridge kinetics are temperature-dependent, with a Q10 of at least 2.7. BACKGROUND Dynamic stiffness measurements have revealed acute and chronic alterations of actomyosin cross-bridge kinetics in cardiac muscles of a variety of different animal species. We studied dynamic stiffness in right atrial and left ventricular preparations of non-failing and failing human hearts and tested the influence of the temperature and beta-adrenergic stimulation on cross-bridge kinetics. METHODS AND RESULTS Muscle strips were prepared from right atria and left ventricles from human non-failing and failing hearts. After withdrawal of calcium, steady contracture tension was induced by the addition of 1.5 mM barium chloride. Sinusoidal length oscillations of 1% muscle length were applied, with a frequency spectrum of between 0.1 and 60 Hz. Dynamic stiffness was calculated from the length change and the corresponding force response amplitude. The specific minimum stiffness frequency, which indicates the interaction between cross-bridge recruitment and cross-bridge cycling dynamics, was analyzed for each condition: (1) The minimum stiffness frequency was 0.78 +/- 0.04 Hz in left ventricular myocardium and 2.80 +/- 0.31 Hz in right atrial myocardium (p < 0.01) at 27 degrees C. (2) The minimum stiffness frequency was 41% higher in non-failing compared to failing left ventricular human myocardium. (3) Over a wide range of experimental temperatures, the minimum stiffness frequency changed, with a Q10 of at least 2.7. (4) beta-Adrenergic stimulation significantly (p < 0.05) increased the minimum stiffness to 18 +/- 3% higher frequencies and significantly (p < 0.05) lowered contracture tension by 7 +/- 1%. CONCLUSIONS The contractility of human heart muscle is not only regulated by excitation-contraction coupling but also by modulation of intrinsic properties of the actomyosin system. Acute and chronic alterations of cross-bridge kinetics have been demonstrated, which play a significant role in the physiology and pathophysiology of the human heart.
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Affiliation(s)
- T Ruf
- Department of Cardiology and Angiology, Internal Medicine, University of Freiburg, Germany
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