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Gharagozloo K, Mehdizadeh M, Heckman G, Rose RA, Howlett J, Howlett SE, Nattel S. Heart Failure with Preserved Ejection Fraction in the Elderly: Basic Mechanisms and Clinical Considerations. Can J Cardiol 2024:S0828-282X(24)00302-7. [PMID: 38604339 DOI: 10.1016/j.cjca.2024.04.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 04/04/2024] [Accepted: 04/06/2024] [Indexed: 04/13/2024] Open
Abstract
Heart failure (HF) with preserved ejection fraction (HFpEF) refers to a clinical condition in which the signs of HF, such as pulmonary congestion, peripheral edema and increased natriuretic-peptide levels, are present despite normal ejection-fractions and the absence of other causes (e.g. pericardial disease). The ejection-fraction cutoff for the definition of HFpEF has varied in the past, but recent society guidelines have settled on a consensus of 50%. HFpEF is particularly common in the elderly. The aim of this narrative review is to summarize the available literature regarding HFpEF in the elderly in terms of evidence for the age-dependence, specific clinical features and underlying mechanisms. In the clinical arena, we review the epidemiology, discuss distinct clinical phenotypes typically seen in the elderly, the importance of frailty, the role of biomarkers and the role of medical therapies (including sodium-glucose cotransport protein 2 (SGLT2)-inhibitors, renin-angiotensin-aldosterone system (RAAS) blockers, angiotensin-receptor/neprilysin inhibitors, diuretics and beta-adrenergic receptor blockers). We then go on to discuss the basic mechanisms implicated in HFpEF, including cellular senescence, fibrosis, inflammation, mitochondrial dysfunction, enhanced production of reactive-oxygen species, abnormal cellular calcium handling, changes in microRNA signaling, insulin resistance, and sex-hormone changes. Finally, we review knowledge gaps and promising areas of future investigation. Improved understanding of the specific clinical manifestations of HFpEF in the elderly and of the fundamental mechanisms contributing to the age-related risk of HFpEF promises to lead to novel diagnostic and treatment approaches that will improve outcomes for this common cardiac disorder in a vulnerable population.
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Affiliation(s)
- Kimia Gharagozloo
- Montreal Heart Institute Research Center and Université de Montréal, Montréal, Canada; McGill University Departments of Pharmacology and Therapeutics, Montréal, Canada
| | - Mozhdeh Mehdizadeh
- Montreal Heart Institute Research Center and Université de Montréal, Montréal, Canada; McGill University Departments of Pharmacology and Therapeutics, Montréal, Canada
| | - George Heckman
- Schlegel Research Institute for Aging and University of Waterloo
| | - Robert A Rose
- Department of Cardiac Sciences, Department of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary
| | - Jonathan Howlett
- Libin Cardiovascular Institute and Department of Cardiac Sciences, Cumming School of Medicine, University of Calgary
| | - Susan E Howlett
- Departments of Pharmacology and Medicine (Geriatric Medicine), Dalhousie University
| | - Stanley Nattel
- Montreal Heart Institute Research Center and Université de Montréal, Montréal, Canada; McGill University Departments of Pharmacology and Therapeutics, Montréal, Canada; Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Germany.
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Rose RA, Howlett SE. Preclinical studies on the impacts of frailty in the aging heart. Can J Cardiol 2024:S0828-282X(24)00200-9. [PMID: 38460611 DOI: 10.1016/j.cjca.2024.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 02/20/2024] [Accepted: 03/04/2024] [Indexed: 03/11/2024] Open
Abstract
Age is a major risk factor for the development of cardiovascular diseases in men and in women. However, not all people age at the same rate and those who are aging rapidly are considered frail, when compared to their fit counterparts. Frailty is an important clinical challenge because those who are frail are more likely to develop and die from illnesses, including cardiovascular diseases, than fit people of the same age. This increase in susceptibility to cardiovascular diseases in older individuals may occur as the cellular and molecular mechanisms involved in the aging process facilitate structural and functional damage in the heart. Consistent with this, recent studies in murine frailty models have provided strong evidence that maladaptive cardiac remodeling in older mice is the most pronounced in mice with a high level of frailty. For example, there is evidence that ventricular hypertrophy and contractile dysfunction increase as frailty increases in aging mice. Additionally, fibrosis and slowing of conduction in the sinoatrial node and atria are proportional to the level of frailty. These modifications could predispose frail older adults to diseases like heart failure and atrial fibrillation. This preclinical work also raises the possibility that emerging interventions designed to "treat frailty" may also treat or prevent cardiovascular diseases. These findings may help to explain why frail older people are most likely to develop these disorders as they age.
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Affiliation(s)
- Robert A Rose
- Department of Cardiac Sciences and; Department of Physiology and Pharmacology, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
| | - Susan E Howlett
- Department of Pharmacology and; Department of Medicine (Geriatric Medicine), Faculty of Medicine, Dalhousie University, Halifax, NS, Canada.
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Dorey TW, McRae MD, Belke DD, Rose RA. PDE4D mediates impaired β-adrenergic receptor signalling in the sinoatrial node in mice with hypertensive heart disease. Cardiovasc Res 2023; 119:2697-2711. [PMID: 37643895 PMCID: PMC10757582 DOI: 10.1093/cvr/cvad138] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 06/06/2023] [Accepted: 07/18/2023] [Indexed: 08/31/2023] Open
Abstract
AIMS The sympathetic nervous system increases HR by activating β-adrenergic receptors (β-ARs) and increasing cAMP in sinoatrial node (SAN) myocytes while phosphodiesterases (PDEs) degrade cAMP. Chronotropic incompetence, the inability to regulate heart rate (HR) in response to sympathetic nervous system activation, is common in hypertensive heart disease; however, the basis for this is poorly understood. The objective of this study was to determine the mechanisms leading to chronotropic incompetence in mice with angiotensin II (AngII)-induced hypertensive heart disease. METHODS AND RESULTS C57BL/6 mice were infused with saline or AngII (2.5 mg/kg/day for 3 weeks) to induce hypertensive heart disease. HR and SAN function in response to the β-AR agonist isoproterenol (ISO) were studied in vivo using telemetry and electrocardiography, in isolated atrial preparations using optical mapping, in isolated SAN myocytes using patch-clamping, and using molecular biology. AngII-infused mice had smaller increases in HR in response to physical activity and during acute ISO injection. Optical mapping of the SAN in AngII-infused mice demonstrated impaired increases in conduction velocity and altered conduction patterns in response to ISO. Spontaneous AP firing responses to ISO in isolated SAN myocytes from AngII-infused mice were impaired due to smaller increases in diastolic depolarization (DD) slope, hyperpolarization-activated current (If), and L-type Ca2+ current (ICa,L). These changes were due to increased localization of PDE4D surrounding β1- and β2-ARs in the SAN, increased SAN PDE4 activity, and reduced cAMP generation in response to ISO. Knockdown of PDE4D using a virus-delivered shRNA or inhibition of PDE4 with rolipram normalized SAN sensitivity to β-AR stimulation in AngII-infused mice. CONCLUSIONS AngII-induced hypertensive heart disease results in impaired HR responses to β-AR stimulation due to up-regulation of PDE4D and reduced effects of cAMP on spontaneous AP firing in SAN myocytes.
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Affiliation(s)
- Tristan W Dorey
- Libin Cardiovascular Institute, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, AB, T2N 4Z6, Canada
| | - Megan D McRae
- Libin Cardiovascular Institute, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, AB, T2N 4Z6, Canada
| | - Darrell D Belke
- Libin Cardiovascular Institute, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, AB, T2N 4Z6, Canada
| | - Robert A Rose
- Libin Cardiovascular Institute, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, AB, T2N 4Z6, Canada
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Chakraborty P, Azam MA, Massé S, Lai PF, Rose RA, Ibarra Moreno CA, Riazi S, Nanthakumar K. Uncoupling cytosolic calcium from membrane voltage by transient receptor potential melastatin 4 channel (TRPM4) modulation: A novel strategy to treat ventricular arrhythmias. Heart Rhythm O2 2023; 4:725-732. [PMID: 38034891 PMCID: PMC10685170 DOI: 10.1016/j.hroo.2023.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2023] Open
Abstract
The current antiarrhythmic paradigm is mainly centered around modulating membrane voltage. However, abnormal cytosolic calcium (Ca2+) signaling, which plays an important role in driving membrane voltage, has not been targeted for therapeutic purposes in arrhythmogenesis. There is clear evidence for bidirectional coupling between membrane voltage and intracellular Ca2+. Cytosolic Ca2+ regulates membrane voltage through Ca2+-sensitive membrane currents. As a component of Ca2+-sensitive currents, Ca2+-activated nonspecific cationic current through the TRPM4 (transient receptor potential melastatin 4) channel plays a significant role in Ca2+-driven changes in membrane electrophysiology. In myopathic and ischemic ventricles, upregulation and/or enhanced activity of this current is associated with the generation of afterdepolarization (both early and delayed), reduction of repolarization reserve, and increased propensity to ventricular arrhythmias. In this review, we describe a novel concept for the management of ventricular arrhythmias in the remodeled ventricle based on mechanistic concepts from experimental studies, by uncoupling the Ca2+-induced changes in membrane voltage by inhibition of this TRPM4-mediated current.
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Affiliation(s)
- Praloy Chakraborty
- Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
| | - Mohammed Ali Azam
- Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
| | - Stéphane Massé
- Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
| | - Patrick F.H. Lai
- Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
| | - Robert A. Rose
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Carlos A. Ibarra Moreno
- Malignant Hyperthermia Investigation Unit, Department of Anesthesiology and Pain Medicine, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
| | - Sheila Riazi
- Malignant Hyperthermia Investigation Unit, Department of Anesthesiology and Pain Medicine, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
| | - Kumaraswamy Nanthakumar
- Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
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Dorey TW, Liu Y, Jansen HJ, Bohne LJ, Mackasey M, Atkinson L, Prasai S, Belke DD, Fatehi-Hassanabad A, Fedak PWM, Rose RA. Natriuretic Peptide Receptor B Protects Against Atrial Fibrillation by Controlling Atrial cAMP Via Phosphodiesterase 2. Circ Arrhythm Electrophysiol 2023; 16:e012199. [PMID: 37933567 DOI: 10.1161/circep.123.012199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 10/19/2023] [Indexed: 11/08/2023]
Abstract
BACKGROUND β-AR (β-adrenergic receptor) stimulation regulates atrial electrophysiology and Ca2+ homeostasis via cAMP-dependent mechanisms; however, enhanced β-AR signaling can promote atrial fibrillation (AF). CNP (C-type natriuretic peptide) can also regulate atrial electrophysiology through the activation of NPR-B (natriuretic peptide receptor B) and cGMP-dependent signaling. Nevertheless, the role of NPR-B in regulating atrial electrophysiology, Ca2+ homeostasis, and atrial arrhythmogenesis is incompletely understood. METHODS Studies were performed using atrial samples from human patients with AF or sinus rhythm and in wild-type and NPR-B-deficient (NPR-B+/-) mice. Studies were conducted in anesthetized mice by intracardiac electrophysiology, in isolated mouse atrial preparations using high-resolution optical mapping, in isolated mouse and human atrial myocytes using patch-clamping and Ca2+ imaging, and in mouse and human atrial tissues using molecular biology. RESULTS Atrial NPR-B protein levels were reduced in patients with AF, and NPR-B+/- mice were more susceptible to AF. Atrial cGMP levels and PDE2 (phosphodiesterase 2) activity were reduced in NPR-B+/- mice leading to larger increases in atrial cAMP in the presence of the β-AR agonist isoproterenol. NPR-B+/- mice displayed larger increases in action potential duration and L-type Ca2+ current in the presence of isoproterenol. This resulted in the occurrence of spontaneous sarcoplasmic reticulum Ca2+ release events and delayed afterdepolarizations in NPR-B+/- atrial myocytes. Phosphorylation of the RyR2 (ryanodine receptor) and phospholamban was increased in NPR-B+/- atria in the presence of isoproterenol compared with the wildtypes. C-type natriuretic peptide inhibited isoproterenol-stimulated L-type Ca2+ current through PDE2 in mouse and human atrial myocytes. CONCLUSIONS NPR-B protects against AF by preventing enhanced atrial responses to β-adrenergic receptor agonists.
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Affiliation(s)
- Tristan W Dorey
- Department of Cardiac Sciences (T.W.D., Y.L., H.J.J., L.J.B., M.M., S.P., D.D.B, A.F.-H., P.W.M.F., R.A.R.), Libin Cardiovascular Institute, Cumming School of Medicine University of Calgary, Alberta, Canada
- Department of Physiology and Pharmacology (T.W.D., Y.L., H.J.J., L.J.B., M.M., S.P., R.A.R.), Libin Cardiovascular Institute, Cumming School of Medicine University of Calgary, Alberta, Canada
| | - Yingjie Liu
- Department of Cardiac Sciences (T.W.D., Y.L., H.J.J., L.J.B., M.M., S.P., D.D.B, A.F.-H., P.W.M.F., R.A.R.), Libin Cardiovascular Institute, Cumming School of Medicine University of Calgary, Alberta, Canada
- Department of Physiology and Pharmacology (T.W.D., Y.L., H.J.J., L.J.B., M.M., S.P., R.A.R.), Libin Cardiovascular Institute, Cumming School of Medicine University of Calgary, Alberta, Canada
| | - Hailey J Jansen
- Department of Cardiac Sciences (T.W.D., Y.L., H.J.J., L.J.B., M.M., S.P., D.D.B, A.F.-H., P.W.M.F., R.A.R.), Libin Cardiovascular Institute, Cumming School of Medicine University of Calgary, Alberta, Canada
- Department of Physiology and Pharmacology (T.W.D., Y.L., H.J.J., L.J.B., M.M., S.P., R.A.R.), Libin Cardiovascular Institute, Cumming School of Medicine University of Calgary, Alberta, Canada
| | - Loryn J Bohne
- Department of Cardiac Sciences (T.W.D., Y.L., H.J.J., L.J.B., M.M., S.P., D.D.B, A.F.-H., P.W.M.F., R.A.R.), Libin Cardiovascular Institute, Cumming School of Medicine University of Calgary, Alberta, Canada
- Department of Physiology and Pharmacology (T.W.D., Y.L., H.J.J., L.J.B., M.M., S.P., R.A.R.), Libin Cardiovascular Institute, Cumming School of Medicine University of Calgary, Alberta, Canada
| | - Martin Mackasey
- Department of Cardiac Sciences (T.W.D., Y.L., H.J.J., L.J.B., M.M., S.P., D.D.B, A.F.-H., P.W.M.F., R.A.R.), Libin Cardiovascular Institute, Cumming School of Medicine University of Calgary, Alberta, Canada
- Department of Physiology and Pharmacology (T.W.D., Y.L., H.J.J., L.J.B., M.M., S.P., R.A.R.), Libin Cardiovascular Institute, Cumming School of Medicine University of Calgary, Alberta, Canada
| | - Logan Atkinson
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada (L.A.)
| | - Shuvam Prasai
- Department of Cardiac Sciences (T.W.D., Y.L., H.J.J., L.J.B., M.M., S.P., D.D.B, A.F.-H., P.W.M.F., R.A.R.), Libin Cardiovascular Institute, Cumming School of Medicine University of Calgary, Alberta, Canada
- Department of Physiology and Pharmacology (T.W.D., Y.L., H.J.J., L.J.B., M.M., S.P., R.A.R.), Libin Cardiovascular Institute, Cumming School of Medicine University of Calgary, Alberta, Canada
| | - Darrell D Belke
- Department of Cardiac Sciences (T.W.D., Y.L., H.J.J., L.J.B., M.M., S.P., D.D.B, A.F.-H., P.W.M.F., R.A.R.), Libin Cardiovascular Institute, Cumming School of Medicine University of Calgary, Alberta, Canada
| | - Ali Fatehi-Hassanabad
- Department of Cardiac Sciences (T.W.D., Y.L., H.J.J., L.J.B., M.M., S.P., D.D.B, A.F.-H., P.W.M.F., R.A.R.), Libin Cardiovascular Institute, Cumming School of Medicine University of Calgary, Alberta, Canada
| | - Paul W M Fedak
- Department of Cardiac Sciences (T.W.D., Y.L., H.J.J., L.J.B., M.M., S.P., D.D.B, A.F.-H., P.W.M.F., R.A.R.), Libin Cardiovascular Institute, Cumming School of Medicine University of Calgary, Alberta, Canada
| | - Robert A Rose
- Department of Cardiac Sciences (T.W.D., Y.L., H.J.J., L.J.B., M.M., S.P., D.D.B, A.F.-H., P.W.M.F., R.A.R.), Libin Cardiovascular Institute, Cumming School of Medicine University of Calgary, Alberta, Canada
- Department of Physiology and Pharmacology (T.W.D., Y.L., H.J.J., L.J.B., M.M., S.P., R.A.R.), Libin Cardiovascular Institute, Cumming School of Medicine University of Calgary, Alberta, Canada
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Bohne LJ, Jansen HJ, Dorey TW, Daniel IM, Jamieson KL, Belke DD, McRae MD, Rose RA. Glucagon-Like Peptide-1 Protects Against Atrial Fibrillation and Atrial Remodeling in Type 2 Diabetic Mice. JACC Basic Transl Sci 2023; 8:922-936. [PMID: 37719430 PMCID: PMC10504404 DOI: 10.1016/j.jacbts.2023.01.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 01/04/2023] [Accepted: 01/04/2023] [Indexed: 09/19/2023]
Abstract
Atrial fibrillation (AF) is highly prevalent in type 2 diabetes where it increases morbidity and mortality. Glucagon-like peptide (GLP)-1 receptor agonists are used in the treatment of type 2 diabetes (T2DM), but their effects on AF in T2DM are poorly understood. The present study demonstrates type 2 diabetic db/db mice are highly susceptible to AF in association with atrial electrical and structural remodeling. GLP-1, as well as the long-acting GLP-1 analogue liraglutide, reduced AF and prevented atrial remodeling in db/db mice. These data suggest that GLP-1 and related analogues could protect against AF in patients with T2DM.
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Affiliation(s)
- Loryn J. Bohne
- Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; Department of Cardiac Sciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; and the Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Hailey J. Jansen
- Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; Department of Cardiac Sciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; and the Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Tristan W. Dorey
- Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; Department of Cardiac Sciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; and the Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Irene M. Daniel
- Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; Department of Cardiac Sciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; and the Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - K. Lockhart Jamieson
- Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; Department of Cardiac Sciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; and the Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Darrell D. Belke
- Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; Department of Cardiac Sciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; and the Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Megan D. McRae
- Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; Department of Cardiac Sciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; and the Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Robert A. Rose
- Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; Department of Cardiac Sciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; and the Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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Banga S, Mishra M, Heinze-Milne SD, Jansen HJ, Rose RA, Howlett SE. Chronic Testosterone Deficiency Increases Late Inward Sodium Current and Promotes Triggered Activity in Ventricular Myocytes from Aging Male Mice. Am J Physiol Heart Circ Physiol 2023. [PMID: 37389950 DOI: 10.1152/ajpheart.00505.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 06/19/2023] [Indexed: 07/02/2023]
Abstract
Clinical studies suggest low testosterone levels are associated with cardiac arrhythmias, especially in later life. We investigated whether chronic exposure to low circulating testosterone promoted maladaptive electrical remodeling in ventricular myocytes from aging male mice and determined the role of late inward sodium current (INa-L) in this remodeling. C57BL/6 mice had a gonadectomy (GDX) or sham surgery (1-month) and were aged to 22-28-months. Ventricular myocytes were isolated; transmembrane voltage and currents were recorded (37°C). Action potential duration at 70 and 90% repolarization (APD70 and APD90) was prolonged in GDX compared to sham myocytes (APD90: 96.9±3.2 vs 55.4±2.0 ms; p<0.001). INa-L was also larger in GDX than sham (-2.4±0.4 vs -1.2±0.2 pA/pF; p=0.002). When cells were exposed to the INa-L antagonist ranolazine (10 µM), INa-L declined in GDX cells (-1.9±0.5 vs -0.4±0.2 pA/pF; p<0.001) and APD90 was reduced (96.3±14.8 vs 49.2±9.4 ms; p=0.001). GDX cells had more triggered activity (early/delayed afterdepolarizations, EADs/DADs) and spontaneous activity than sham. EADs were inhibited by ranolazine in GDX cells. The selective NaV1.8 blocker A-803467 (30 nM) also reduced INa-L, decreased APD and abolished triggered activity in GDX cells. Scn5a (NaV1.5) and Scn10a (NaV1.8) mRNA was increased in GDX ventricles, but only NaV1.8 protein abundance was increased in GDX compared to sham. In vivo studies showed QT prolongation and more arrhythmias in GDX mice. Thus, triggered activity in ventricular myocytes from aging male mice with long-term testosterone deficiency arises from APD prolongation mediated by larger NaV1.8- and NaV1.5-associated currents, which may explain the increase in arrhythmias.
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Affiliation(s)
- Shubham Banga
- Department of Pharmacology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Manish Mishra
- Department of Pharmacology, Dalhousie University, Halifax, Nova Scotia, Canada
| | | | - Hailey J Jansen
- Department of Cardiac Sciences, University of Calgary, Calgary, Canada
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada
| | - Robert A Rose
- Department of Cardiac Sciences, University of Calgary, Calgary, Canada
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada
| | - Susan E Howlett
- Department of Pharmacology, Dalhousie University, Halifax, Nova Scotia, Canada
- Department of Medicine (Geriatric Medicine), Dalhousie University, Halifax, NS, Canada
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Ripplinger CM, Glukhov AV, Kay MW, Boukens BJ, Chiamvimonvat N, Delisle BP, Fabritz L, Hund TJ, Knollmann BC, Li N, Murray KT, Poelzing S, Quinn TA, Remme CA, Rentschler SL, Rose RA, Posnack NG. Guidelines for assessment of cardiac electrophysiology and arrhythmias in small animals. Am J Physiol Heart Circ Physiol 2022; 323:H1137-H1166. [PMID: 36269644 PMCID: PMC9678409 DOI: 10.1152/ajpheart.00439.2022] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Cardiac arrhythmias are a major cause of morbidity and mortality worldwide. Although recent advances in cell-based models, including human-induced pluripotent stem cell-derived cardiomyocytes (iPSC-CM), are contributing to our understanding of electrophysiology and arrhythmia mechanisms, preclinical animal studies of cardiovascular disease remain a mainstay. Over the past several decades, animal models of cardiovascular disease have advanced our understanding of pathological remodeling, arrhythmia mechanisms, and drug effects and have led to major improvements in pacing and defibrillation therapies. There exist a variety of methodological approaches for the assessment of cardiac electrophysiology and a plethora of parameters may be assessed with each approach. This guidelines article will provide an overview of the strengths and limitations of several common techniques used to assess electrophysiology and arrhythmia mechanisms at the whole animal, whole heart, and tissue level with a focus on small animal models. We also define key electrophysiological parameters that should be assessed, along with their physiological underpinnings, and the best methods with which to assess these parameters.
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Affiliation(s)
- Crystal M. Ripplinger
- 1Department of Pharmacology, University of California Davis School of Medicine, Davis, California
| | - Alexey V. Glukhov
- 2Department of Medicine, Cardiovascular Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - Matthew W. Kay
- 3Department of Biomedical Engineering, The George Washington University, Washington, District of Columbia
| | - Bastiaan J. Boukens
- 4Department Physiology, University Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands,5Department of Medical Biology, University of Amsterdam, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Nipavan Chiamvimonvat
- 1Department of Pharmacology, University of California Davis School of Medicine, Davis, California,6Department of Internal Medicine, University of California Davis School of Medicine, Davis, California,7Veterans Affairs Northern California Healthcare System, Mather, California
| | - Brian P. Delisle
- 8Department of Physiology, University of Kentucky, Lexington, Kentucky
| | - Larissa Fabritz
- 9University Center of Cardiovascular Science, University Heart and Vascular Center, University Hospital Hamburg-Eppendorf with DZHK Hamburg/Kiel/Luebeck, Germany,10Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Thomas J. Hund
- 11Department of Internal Medicine, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio,12Department of Biomedical Engineering, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| | - Bjorn C. Knollmann
- 13Vanderbilt Center for Arrhythmia Research and Therapeutics, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Na Li
- 14Department of Medicine, Baylor College of Medicine, Houston, Texas
| | - Katherine T. Murray
- 15Departments of Medicine and Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Steven Poelzing
- 16Virginia Tech Carilon School of Medicine, Center for Heart and Reparative Medicine Research, Fralin Biomedical Research Institute at Virginia Tech, Roanoke, Virginia,17Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
| | - T. Alexander Quinn
- 18Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada,19School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Carol Ann Remme
- 20Department of Experimental Cardiology, Heart Centre, Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias Amsterdam UMC Location University of Amsterdam, Amsterdam, The Netherlands
| | - Stacey L. Rentschler
- 21Cardiovascular Division, Department of Medicine, Washington University in Saint Louis, School of Medicine, Saint Louis, Missouri
| | - Robert A. Rose
- 22Department of Cardiac Sciences, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada,23Department of Physiology and Pharmacology, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Nikki G. Posnack
- 24Sheikh Zayed Institute for Pediatric Surgical Innovation, Children’s National Hospital, Washington, District of Columbia,25Department of Pediatrics, George Washington University School of Medicine, Washington, District of Columbia
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9
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Jansen HJ, McRae MD, Mackasey M, Rose RA. Regional and temporal progression of atrial remodeling in angiotensin II mediated atrial fibrillation. Front Physiol 2022; 13:1021807. [DOI: 10.3389/fphys.2022.1021807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 10/17/2022] [Indexed: 11/13/2022] Open
Abstract
Atrial fibrillation (AF) is associated with electrical and structural remodeling in the atria; however, the regional and temporal progression of atrial remodeling is incompletely understood. The objective of this study was to investigate the regional and temporal progression of atrial remodeling leading to changes in AF susceptibility in angiotensin II (Ang II) mediated hypertension. Mice were infused with Ang II for 3, 10 or 21 days. AF susceptibility and atrial electrophysiology were studied in vivo using intracardiac electrophysiology. Right and left atrial myocyte electrophysiology was studied using patch-clamping. Atrial fibrosis was assessed histologically. P wave duration and atrial effective refractory period increased progressively from 3 to 21 days of Ang II. AF susceptibility tended to be increased at 10 days of Ang II and was elevated at 21 days of Ang II. Left, but not right, atrial AP upstroke velocity and Na+ current were reduced at 10 and 21 days of Ang II. Left atrial action potential (AP) duration increased progressively from 3 to 21 days of Ang II due to reductions in repolarizing K+ current. Right atrial AP prolongation was increased only after 21 days of Ang II. Left and right atrial fibrosis developed progressively from 3 to 21 days, but increases were larger in the left atrium. In conclusion, Ang II mediated atrial electrical and structural remodeling develop earlier and more extensively in the left atrium compared to the right atrium, providing insight into how atrial remodeling leads to enhanced AF susceptibility in Ang II mediated hypertension.
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10
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Moghtadaei M, Dorey TW, Rose RA. Evaluation of non-linear heart rate variability using multi-scale multi-fractal detrended fluctuation analysis in mice: Roles of the autonomic nervous system and sinoatrial node. Front Physiol 2022; 13:970393. [PMID: 36237525 PMCID: PMC9552224 DOI: 10.3389/fphys.2022.970393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 08/18/2022] [Indexed: 11/16/2022] Open
Abstract
Nonlinear analyses of heart rate variability (HRV) can be used to quantify the unpredictability, fractal properties and complexity of heart rate. Fractality and its analysis provides valuable information about cardiovascular health. Multi-Scale Multi-Fractal Detrended Fluctuation Analysis (MSMFDFA) is a complexity-based algorithm that can be used to quantify the multi-fractal dynamics of the HRV time series through investigating characteristic exponents at different time scales. This method is applicable to short time series and it is robust to noise and nonstationarity. We have used MSMFDFA, which enables assessment of HRV in the frequency ranges encompassing the very-low frequency and ultra-low frequency bands, to jointly assess multi-scale and multi-fractal dynamics of HRV signals obtained from telemetric ECG recordings in wildtype mice at baseline and after autonomic nervous system (ANS) blockade, from electrograms recorded from isolated atrial preparations and from spontaneous action potential recordings in isolated sinoatrial node myocytes. Data demonstrate that the fractal profile of the intrinsic heart rate is significantly different from the baseline heart rate in vivo, and it is also altered after ANS blockade at specific scales and fractal order domains. For beating rate in isolated atrial preparations and intrinsic heart rate in vivo, the average fractal structure of the HRV increased and multi-fractality strength decreased. These data demonstrate that fractal properties of the HRV depend on both ANS activity and intrinsic sinoatrial node function and that assessing multi-fractality at different time scales is an effective approach for HRV assessment.
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Affiliation(s)
- Motahareh Moghtadaei
- Department of Cardiac Sciences, Cumming School of Medicine, Libin Cardiovascular Institute, University of Calgary, Calgary, AB, Canada
- Department of Physiology and Pharmacology, Cumming School of Medicine, Libin Cardiovascular Institute, University of Calgary, Calgary, AB, Canada
| | - Tristan W. Dorey
- Department of Cardiac Sciences, Cumming School of Medicine, Libin Cardiovascular Institute, University of Calgary, Calgary, AB, Canada
- Department of Physiology and Pharmacology, Cumming School of Medicine, Libin Cardiovascular Institute, University of Calgary, Calgary, AB, Canada
| | - Robert A. Rose
- Department of Cardiac Sciences, Cumming School of Medicine, Libin Cardiovascular Institute, University of Calgary, Calgary, AB, Canada
- Department of Physiology and Pharmacology, Cumming School of Medicine, Libin Cardiovascular Institute, University of Calgary, Calgary, AB, Canada
- *Correspondence: Robert A. Rose,
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11
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Rose RA. Targeting the mitochondrial calcium uniporter to prevent ventricular arrhythmias in heart failure. Heart Rhythm 2022; 19:1736-1737. [PMID: 35718317 DOI: 10.1016/j.hrthm.2022.06.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 06/14/2022] [Indexed: 11/24/2022]
Affiliation(s)
- Robert A Rose
- Libin Cardiovascular Institute, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
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12
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Bohne LJ, Dorey TW, Jansen HJ, Rose RA. PO-675-01 GLUCAGON-LIKE PEPTIDE-1 PREVENTS ATRIAL ELECTRICAL REMODELING IN TYPE 2 DIABETIC DB/DB MICE. Heart Rhythm 2022. [DOI: 10.1016/j.hrthm.2022.03.449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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13
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Jansen HJ, Moghtadaei M, Rafferty SA, Rose RA. Loss of natriuretic peptide receptor C enhances sinoatrial node dysfunction in aging and frail mice. J Gerontol A Biol Sci Med Sci 2021; 77:902-908. [PMID: 34865023 DOI: 10.1093/gerona/glab357] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Indexed: 11/14/2022] Open
Abstract
Heart rate is controlled by the sinoatrial node (SAN). SAN dysfunction is highly prevalent in aging; however, not all individuals age at the same rate. Rather, health status during aging is affected by frailty. Natriuretic peptides regulate SAN function in part by activating natriuretic peptide receptor C (NPR-C). The impacts of NPR-C on HR and SAN function in aging and as a function of frailty are unknown. Frailty was measured in aging wildtype (WT) and NPR-C knockout (NPR-C -/-) mice using a mouse clinical frailty index (FI). HR and SAN structure and function were investigated using intracardiac electrophysiology in anesthetized mice, high-resolution optical mapping in intact atrial preparations, histology and molecular biology. NPR-C -/- mice rapidly became frail leading to shortened lifespan. HR and SAN recovery time were increased in older vs. younger mice and this was exacerbated in NPR-C -/- mice; however, there was substantial variability among age groups and genotypes. HR and SAN recovery time were correlated with FI score and fell along a continuum regardless of age or genotype. Optical mapping demonstrates impairments in SAN function that were also strongly correlated with FI score. SAN fibrosis was increased in aged and NPR-C -/- mice and was graded by FI score. Loss of NPR-C results in accelerated aging due to a rapid decline in health status in association with impairments in HR and SAN function. Frailty assessment was effective and often better able to distinguish aging-dependent changes in SAN function in the setting of shorted lifespan due to loss of NPR-C.
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Affiliation(s)
- Hailey J Jansen
- Libin Cardiovascular Institute, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine , University of Calgary, Calgary, Alberta, Canada
| | - Motahareh Moghtadaei
- Libin Cardiovascular Institute, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine , University of Calgary, Calgary, Alberta, Canada
| | - Sara A Rafferty
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Robert A Rose
- Libin Cardiovascular Institute, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine , University of Calgary, Calgary, Alberta, Canada
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14
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Tuomi JM, Bohne LJ, Dorey TW, Jansen HJ, Liu Y, Jones DL, Rose RA. Distinct Effects of Ibrutinib and Acalabrutinib on Mouse Atrial and Sinoatrial Node Electrophysiology and Arrhythmogenesis. J Am Heart Assoc 2021; 10:e022369. [PMID: 34726066 PMCID: PMC8751944 DOI: 10.1161/jaha.121.022369] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Background Ibrutinib and acalabrutinib are Bruton tyrosine kinase inhibitors used in the treatment of B‐cell lymphoproliferative disorders. Ibrutinib is associated with new‐onset atrial fibrillation. Cases of sinus bradycardia and sinus arrest have also been reported following ibrutinib treatment. Conversely, acalabrutinib is less arrhythmogenic. The basis for these different effects is unclear. Methods and Results The effects of ibrutinib and acalabrutinib on atrial electrophysiology were investigated in anesthetized mice using intracardiac electrophysiology, in isolated atrial preparations using high‐resolution optical mapping, and in isolated atrial and sinoatrial node (SAN) myocytes using patch‐clamping. Acute delivery of acalabrutinib did not affect atrial fibrillation susceptibility or other measures of atrial electrophysiology in mice in vivo. Optical mapping demonstrates that ibrutinib dose‐dependently impaired atrial and SAN conduction and slowed beating rate. Acalabrutinib had no effect on atrial and SAN conduction or beating rate. In isolated atrial myocytes, ibrutinib reduced action potential upstroke velocity and Na+ current. In contrast, acalabrutinib had no effects on atrial myocyte upstroke velocity or Na+ current. Both drugs increased action potential duration, but these effects were smaller for acalabrutinib compared with ibrutinib and occurred by different mechanisms. In SAN myocytes, ibrutinib impaired spontaneous action potential firing by inhibiting the delayed rectifier K+ current, while acalabrutinib had no effects on SAN myocyte action potential firing. Conclusions Ibrutinib and acalabrutinib have distinct effects on atrial electrophysiology and ion channel function that provide insight into the basis for increased atrial fibrillation susceptibility and SAN dysfunction with ibrutinib, but not with acalabrutinib.
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Affiliation(s)
- Jari M Tuomi
- Department of Medicine Schulich School of Medicine & Dentistry Western University London Ontario Canada
| | - Loryn J Bohne
- Department of Cardiac Sciences Department of Physiology and Pharmacology Cumming School of Medicine Libin Cardiovascular Institute of AlbertaUniversity of Calgary Calgary Alberta Canada
| | - Tristan W Dorey
- Department of Cardiac Sciences Department of Physiology and Pharmacology Cumming School of Medicine Libin Cardiovascular Institute of AlbertaUniversity of Calgary Calgary Alberta Canada
| | - Hailey J Jansen
- Department of Cardiac Sciences Department of Physiology and Pharmacology Cumming School of Medicine Libin Cardiovascular Institute of AlbertaUniversity of Calgary Calgary Alberta Canada
| | - Yingjie Liu
- Department of Cardiac Sciences Department of Physiology and Pharmacology Cumming School of Medicine Libin Cardiovascular Institute of AlbertaUniversity of Calgary Calgary Alberta Canada
| | - Douglas L Jones
- Department of Medicine Schulich School of Medicine & Dentistry Western University London Ontario Canada.,Department of Physiology & Pharmacology Schulich School of Medicine & Dentistry Western University London Ontario Canada
| | - Robert A Rose
- Department of Cardiac Sciences Department of Physiology and Pharmacology Cumming School of Medicine Libin Cardiovascular Institute of AlbertaUniversity of Calgary Calgary Alberta Canada
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15
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Jamieson KL, Rose RA. New insights into ventricular arrhythmogenesis in a pure model of pulmonary arterial hypertension. Heart Rhythm 2021; 19:125-126. [PMID: 34628041 DOI: 10.1016/j.hrthm.2021.10.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 10/05/2021] [Indexed: 11/24/2022]
Affiliation(s)
- K Lockhart Jamieson
- Libin Cardiovascular Institute, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Robert A Rose
- Libin Cardiovascular Institute, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
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16
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Abstract
[Figure: see text].
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Affiliation(s)
- Hailey J Jansen
- Department of Cardiac Sciences, Department of Physiology and Pharmacology, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Alberta, Canada (H.J.J., M.M., R.A.R.)
| | - Motahareh Moghtadaei
- Department of Cardiac Sciences, Department of Physiology and Pharmacology, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Alberta, Canada (H.J.J., M.M., R.A.R.)
| | - Sara A Rafferty
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada (S.A.R.)
| | - Robert A Rose
- Department of Cardiac Sciences, Department of Physiology and Pharmacology, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Alberta, Canada (H.J.J., M.M., R.A.R.)
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17
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Dorey TW, Jansen HJ, Moghtadaei M, Jamieson KL, Rose RA. Impacts of frailty on heart rate variability in aging mice: Roles of the autonomic nervous system and sinoatrial node. Heart Rhythm 2021; 18:1999-2008. [PMID: 34371195 DOI: 10.1016/j.hrthm.2021.07.069] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 07/27/2021] [Accepted: 07/29/2021] [Indexed: 11/29/2022]
Abstract
BACKGROUND Heart rate variability (HRV) is determined by intrinsic sinoatrial node (SAN) activity and the autonomic nervous system (ANS). HRV is reduced in aging; however, aging is heterogeneous. Frailty, which can be measured using a frailty index (FI), can quantify health status in aging separately from chronological age. OBJECTIVE The purpose of this study was to investigate the impacts of age and frailty on HRV in mice. METHODS Frailty was measured in aging mice between 10 and 130 weeks of age. HRV was assessed using time domain, frequency domain, and Poincaré plot analyses in anesthetized mice at baseline and after ANS blockade, as well as in isolated atrial preparations. RESULTS HRV was reduced in aged mice (90-130 weeks and 50-80 weeks old) compared to younger mice (10-30 weeks old); however, there was substantial variability within age groups. In contrast, HRV was strongly correlated with FI score regardless of chronological age. ANS blockade resulted in reductions in heart rate that were largest in 90- to 130-week-old mice and were correlated with FI score. HRV after ANS blockade or in isolated atrial preparations was increased in aged mice but again showed high variability among age groups. HRV was correlated with FI score after ANS blockade and in isolated atrial preparations. CONCLUSION HRV is reduced in aging mice in association with a shift in sympathovagal balance and increased intrinsic SAN beating variability; however, HRV is highly variable within age groups. HRV was strongly correlated with frailty, which was able to detect differences in HRV separately from chronological age.
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Affiliation(s)
- Tristan W Dorey
- Libin Cardiovascular Institute, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Hailey J Jansen
- Libin Cardiovascular Institute, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Motahareh Moghtadaei
- Libin Cardiovascular Institute, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - K Lockhart Jamieson
- Libin Cardiovascular Institute, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Robert A Rose
- Libin Cardiovascular Institute, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
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18
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Bohne LJ, Tuomi JM, Dorey TW, Jansen HJ, Liu Y, Jones DL, Rose RA. B-PO01-012 DISTINCT EFFECTS OF IBRUTINIB AND ACALABRUTINIB ON ATRIAL AND SINOATRIAL NODE ELECTROPHYSIOLOGY. Heart Rhythm 2021. [DOI: 10.1016/j.hrthm.2021.06.158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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19
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Dorey TW, Mackasey M, Jansen HJ, McRae MD, Bohne LJ, Liu Y, Belke DD, Atkinson L, Rose RA. Natriuretic peptide receptor B maintains heart rate and sinoatrial node function via cyclic GMP-mediated signaling. Cardiovasc Res 2021; 118:1917-1931. [PMID: 34273155 DOI: 10.1093/cvr/cvab245] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 07/16/2021] [Indexed: 11/13/2022] Open
Abstract
AIMS Heart rate (HR) is a critical indicator of cardiac performance that is determined by sinoatrial node (SAN) function and regulation. Natriuretic peptides, including C-type NP (CNP) have been shown to modulate ion channel function in the SAN when applied exogenously. CNP is the only NP that acts as a ligand for natriuretic peptide receptor-B (NPR-B). Despite these properties, the ability of CNP and NPR-B to regulate HR and intrinsic SAN automaticity in vivo, and the mechanisms by which it does so, are incompletely understood. Thus, the objective of this study was to determine the role of NPR-B signaling in regulating HR and SAN function. METHODS AND RESULTS We have used NPR-B deficient mice (NPR-B+/-) to study HR regulation and SAN function using telemetry in conscious mice, intracardiac electrophysiology in anesthetized mice, high resolution optical mapping in isolated SAN preparations, patch-clamping in isolated SAN myocytes, and molecular biology in isolated SAN tissue. These studies demonstrate that NPR-B+/- mice exhibit slow HR, increased corrected SAN recovery time, and slowed SAN conduction. Spontaneous AP firing frequency in isolated SAN myocytes was impaired in NPR-B+/- mice due to reductions in the hyperpolarization activated current (If) and L-type Ca2+ current (ICa,L). If and ICa,L were reduced due to lower cGMP levels and increased hydrolysis of cAMP by phosphodiesterase 3 (PDE3) in the SAN. Inhibiting PDE3 or restoring cGMP signaling via application of 8-Br-cGMP abolished the reductions in cAMP, AP firing, If, and ICa,L, and normalized SAN conduction, in the SAN in NPR-B+/- mice. NPR-B+/- mice did not exhibit changes in SAN fibrosis and showed no evidence of cardiac hypertrophy or changes in ventricular function. CONCLUSIONS NPR-B plays an essential physiological role in maintaining normal HR and SAN function by modulating ion channel function in SAN myocytes via a cGMP/PDE3/cAMP signaling mechanism.
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Affiliation(s)
- Tristan W Dorey
- Libin Cardiovascular Institute, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Martin Mackasey
- Libin Cardiovascular Institute, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Hailey J Jansen
- Libin Cardiovascular Institute, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Megan D McRae
- Libin Cardiovascular Institute, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Loryn J Bohne
- Libin Cardiovascular Institute, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Yingjie Liu
- Libin Cardiovascular Institute, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Darrell D Belke
- Libin Cardiovascular Institute, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Logan Atkinson
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Robert A Rose
- Libin Cardiovascular Institute, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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20
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Sun B, Yao J, Ni M, Wei J, Zhong X, Guo W, Zhang L, Wang R, Belke D, Chen YX, Lieve KVV, Broendberg AK, Roston TM, Blankoff I, Kammeraad JA, von Alvensleben JC, Lazarte J, Vallmitjana A, Bohne LJ, Rose RA, Benitez R, Hove-Madsen L, Napolitano C, Hegele RA, Fill M, Sanatani S, Wilde AAM, Roberts JD, Priori SG, Jensen HK, Chen SRW. Cardiac ryanodine receptor calcium release deficiency syndrome. Sci Transl Med 2021; 13:13/579/eaba7287. [PMID: 33536282 DOI: 10.1126/scitranslmed.aba7287] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 12/07/2020] [Indexed: 11/02/2022]
Abstract
Cardiac ryanodine receptor (RyR2) gain-of-function mutations cause catecholaminergic polymorphic ventricular tachycardia, a condition characterized by prominent ventricular ectopy in response to catecholamine stress, which can be reproduced on exercise stress testing (EST). However, reports of sudden cardiac death (SCD) have emerged in EST-negative individuals who have loss-of-function (LOF) RyR2 mutations. The clinical relevance of RyR2 LOF mutations including their pathogenic mechanism, diagnosis, and treatment are all unknowns. Here, we performed clinical and genetic evaluations of individuals who suffered from SCD and harbored an LOF RyR2 mutation. We carried out electrophysiological studies using a programed electrical stimulation protocol consisting of a long-burst, long-pause, and short-coupled (LBLPS) ventricular extra-stimulus. Linkage analysis of RyR2 LOF mutations in six families revealed a combined logarithm of the odds ratio for linkage score of 11.479 for a condition associated with SCD with negative EST. A RyR2 LOF mouse model exhibited no catecholamine-provoked ventricular arrhythmias as in humans but did have substantial cardiac electrophysiological remodeling and an increased propensity for early afterdepolarizations. The LBLPS pacing protocol reliably induced ventricular arrhythmias in mice and humans having RyR2 LOF mutations, whose phenotype is otherwise concealed before SCD. Furthermore, treatment with quinidine and flecainide abolished LBLPS-induced ventricular arrhythmias in model mice. Thus, RyR2 LOF mutations underlie a previously unknown disease entity characterized by SCD with normal EST that we have termed RyR2 Ca2+ release deficiency syndrome (CRDS). Our study provides insights into the mechanism of CRDS, reports a specific CRDS diagnostic test, and identifies potentially efficacious anti-CRDS therapies.
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Affiliation(s)
- Bo Sun
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB T2N 4Z6, Canada.,Medical School, Kunming University of Science and Technology, Kunming 650504, China
| | - Jinjing Yao
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB T2N 4Z6, Canada
| | - Mingke Ni
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB T2N 4Z6, Canada
| | - Jinhong Wei
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB T2N 4Z6, Canada
| | - Xiaowei Zhong
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB T2N 4Z6, Canada
| | - Wenting Guo
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB T2N 4Z6, Canada
| | - Lin Zhang
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB T2N 4Z6, Canada
| | - Ruiwu Wang
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB T2N 4Z6, Canada
| | - Darrell Belke
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB T2N 4Z6, Canada
| | - Yong-Xiang Chen
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB T2N 4Z6, Canada
| | - Krystien V V Lieve
- Amsterdam University Medical Centre, location AMC, Heart Center, Department of Clinical and Experimental Cardiology, Amsterdam 1105AZ, Netherlands.,European Reference Network 'ERN GUARD-Heart', Amsterdam, Netherlands
| | - Anders K Broendberg
- Department of Cardiology, Aarhus University Hospital, and Department of Clinical Medicine, Health, Aarhus University, Palle Juul-Jensens Blv 99, DK-8200 Aarhus N, Denmark
| | - Thomas M Roston
- Division of Cardiology, Department of Medicine, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
| | - Ivan Blankoff
- C.H.U. Charleroi, Hôpital Civil Marie Curie Chaussée de Bruxelles 140 6042 Charleroi, Belgium
| | - Janneke A Kammeraad
- Department of Pediatric Cardiology, Sophia Children's Hospital, Erasmus University Medical Centre, Doctor Molewaterplein 40, 3015 GD Rotterdam, Netherlands
| | - Johannes C von Alvensleben
- Division of Cardiology, Heart Institute, Children's Hospital Colorado, University of Colorado, Aurora, CO 80045, USA
| | - Julieta Lazarte
- Department of Medicine and Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5B7, Canada
| | - Alexander Vallmitjana
- Department of Automatic Control, Universitat Politècnica de Catalunya, 08034 Barcelona, Spain
| | - Loryn J Bohne
- Departments of Cardiac Sciences and Physiology and Pharmacology, Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4Z6, Canada
| | - Robert A Rose
- Departments of Cardiac Sciences and Physiology and Pharmacology, Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4Z6, Canada
| | - Raul Benitez
- Department of Automatic Control, Universitat Politècnica de Catalunya, 08034 Barcelona, Spain
| | - Leif Hove-Madsen
- Biomedical Research Institute Barcelona (IIBB-CSIC) and IIB Sant Pau, Hospital de Sant Pau, Barcelona 08025, Spain
| | - Carlo Napolitano
- European Reference Network 'ERN GUARD-Heart', Amsterdam, Netherlands.,Division of Cardiology and Molecular Cardiology, IRCCS Maugeri Foundation-University of Pavia, 27100 Pavia, Italy.,Department of Molecular Medicine, University of Pavia, 27100 Pavia, Italy
| | - Robert A Hegele
- Department of Medicine and Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5B7, Canada
| | - Michael Fill
- Department of Physiology and Biophysics, Rush University Medical Center, Chicago, IL 60612, USA
| | - Shubhayan Sanatani
- Child and Family Research Institute, Department of Pediatrics, University of British Columbia, Vancouver, BC V6H 3V4, Canada.
| | - Arthur A M Wilde
- Amsterdam University Medical Centre, location AMC, Heart Center, Department of Clinical and Experimental Cardiology, Amsterdam 1105AZ, Netherlands. .,European Reference Network 'ERN GUARD-Heart', Amsterdam, Netherlands
| | - Jason D Roberts
- Section of Cardiac Electrophysiology, Division of Cardiology, Department of Medicine, Western University, London, ON N6A 5A5, Canada.
| | - Silvia G Priori
- European Reference Network 'ERN GUARD-Heart', Amsterdam, Netherlands. .,Division of Cardiology and Molecular Cardiology, IRCCS Maugeri Foundation-University of Pavia, 27100 Pavia, Italy.,Department of Molecular Medicine, University of Pavia, 27100 Pavia, Italy.,Molecular Cardiology Laboratory, Centro de Investigaciones Cardiovasculares Carlos III, 28029 Madrid, Spain
| | - Henrik K Jensen
- Department of Cardiology, Aarhus University Hospital, and Department of Clinical Medicine, Health, Aarhus University, Palle Juul-Jensens Blv 99, DK-8200 Aarhus N, Denmark.
| | - S R Wayne Chen
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB T2N 4Z6, Canada. .,Department of Physiology and Biophysics, Rush University Medical Center, Chicago, IL 60612, USA
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21
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Jøns C, Porta-Sánchez A, Lai PFH, Wauchop M, Massé S, Azam MA, Asta J, Rose RA, Nanthakumar K. Mechanism of and strategy to mitigate liraglutide-mediated positive chronotropy. Life Sci 2021; 282:119815. [PMID: 34256040 DOI: 10.1016/j.lfs.2021.119815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 06/25/2021] [Accepted: 07/05/2021] [Indexed: 11/18/2022]
Abstract
AIM An adverse side-effect of Liraglutide (LG), a Glucagon-Like Peptide 1 (GLP1)-analog commonly used in treatments for diabetes, is positive chronotropy. The goal of this study is to investigate on the mechanism of this drug-induced chronotropy and explore potential means to mitigate this side-effect so as to maximize the therapeutic benefits from LG. MAIN METHODS Experiments were conducted with: 1) Isolated rabbit hearts in a Langendorff set-up to assess for direct effects of drug actions and 2) Murine cardiomyocytes isolated from the sino-atrial node (SAN) to assess the effects of LG on spontaneous action potential (AP) firing and the hyperpolarization-activated current If. KEY FINDINGS LG induced a dose-dependent increase in heart rate. Its effects on sinus node automaticity, which were not suppressed during β-blockade with Propranolol, were abolished by If blockade with Ivabradine. In isolated murine SAN myocytes, LG increased spontaneous AP firing frequency by an increase in diastolic depolarization slope without changing other electrophysiological parameters. SIGNIFICANCE LG-induced positive chronotropy is partly due to a direct effect on the SAN and is independent of the adrenergic cascade and extrinsic autonomic reflex mechanisms. The direct LG-associated increase in heart rate should be mitigated with If blockers rather than β-blockade.
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Affiliation(s)
- Christian Jøns
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, Toronto, Ontario, Canada; Department of Cardiology, The Heart Centre, Rigshospitalet, Copenhagen, Denmark
| | - Andreu Porta-Sánchez
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, Toronto, Ontario, Canada; Fundación Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain and Hospital Universitario Quirónsalud, Madrid, Spain
| | - Patrick F H Lai
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, Toronto, Ontario, Canada
| | | | - Stéphane Massé
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, Toronto, Ontario, Canada
| | - Mohammed Ali Azam
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, Toronto, Ontario, Canada
| | - John Asta
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, Toronto, Ontario, Canada
| | - Robert A Rose
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada.
| | - Kumaraswamy Nanthakumar
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, Toronto, Ontario, Canada; University of Toronto, Toronto, Ontario, Canada.
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22
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Aguilar M, Rose RA, Takawale A, Nattel S, Reilly S. New aspects of endocrine control of atrial fibrillation and possibilities for clinical translation. Cardiovasc Res 2021; 117:1645-1661. [PMID: 33723575 PMCID: PMC8208746 DOI: 10.1093/cvr/cvab080] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 01/25/2021] [Accepted: 03/11/2021] [Indexed: 12/20/2022] Open
Abstract
Hormones are potent endo-, para-, and autocrine endogenous regulators of the function of multiple organs, including the heart. Endocrine dysfunction promotes a number of cardiovascular diseases, including atrial fibrillation (AF). While the heart is a target for endocrine regulation, it is also an active endocrine organ itself, secreting a number of important bioactive hormones that convey significant endocrine effects, but also through para-/autocrine actions, actively participate in cardiac self-regulation. The hormones regulating heart-function work in concert to support myocardial performance. AF is a serious clinical problem associated with increased morbidity and mortality, mainly due to stroke and heart failure. Current therapies for AF remain inadequate. AF is characterized by altered atrial function and structure, including electrical and profibrotic remodelling in the atria and ventricles, which facilitates AF progression and hampers its treatment. Although features of this remodelling are well-established and its mechanisms are partly understood, important pathways pertinent to AF arrhythmogenesis are still unidentified. The discovery of these missing pathways has the potential to lead to therapeutic breakthroughs. Endocrine dysfunction is well-recognized to lead to AF. In this review, we discuss endocrine and cardiocrine signalling systems that directly, or as a consequence of an underlying cardiac pathology, contribute to AF pathogenesis. More specifically, we consider the roles of products from the hypothalamic-pituitary axis, the adrenal glands, adipose tissue, the renin–angiotensin system, atrial cardiomyocytes, and the thyroid gland in controlling atrial electrical and structural properties. The influence of endocrine/paracrine dysfunction on AF risk and mechanisms is evaluated and discussed. We focus on the most recent findings and reflect on the potential of translating them into clinical application.
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Affiliation(s)
- Martin Aguilar
- Department of Medicine and Research Center, Montreal Heart Institute and Université de Montréal, Montréal, QC, Canada.,Department of Pharmacology and Physiology/Institute of Biomedical Engineering, Université de Montréal, Montréal, QC, Canada
| | - Robert A Rose
- Department of Cardiac Sciences, Department of Physiology and Pharmacology, Libin Cardiovascular Institute, Cumming School of Medicine, Health Research Innovation Center, University of Calgary, AB, Canada
| | - Abhijit Takawale
- Department of Medicine and Research Center, Montreal Heart Institute and Université de Montréal, Montréal, QC, Canada.,Department of Pharmacology and Physiology/Institute of Biomedical Engineering, Université de Montréal, Montréal, QC, Canada.,Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
| | - Stanley Nattel
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada.,Faculty of Medicine, Department of Pharmacology and Physiology, and Research Centre, Montreal Heart Institute and University of Montreal, Montreal, QC, Canada.,Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Germany.,IHU LIRYC and Fondation Bordeaux Université, Bordeaux, France
| | - Svetlana Reilly
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, John Radcliffe Hospital, Oxford, UK
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23
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Bohne LJ, Jansen HJ, Daniel I, Dorey TW, Moghtadaei M, Belke DD, Ezeani M, Rose RA. Electrical and structural remodeling contribute to atrial fibrillation in type 2 diabetic db/db mice. Heart Rhythm 2020; 18:118-129. [PMID: 32911049 DOI: 10.1016/j.hrthm.2020.08.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 08/25/2020] [Accepted: 08/30/2020] [Indexed: 01/24/2023]
Abstract
BACKGROUND Atrial fibrillation (AF) is highly prevalent in diabetes mellitus (DM), yet the basis for this finding is poorly understood. Type 2 DM may be associated with unique patterns of atrial electrical and structural remodeling; however, this has not been investigated in detail. OBJECTIVE The purpose of this study was to investigate AF susceptibility and atrial electrical and structural remodeling in type 2 diabetic db/db mice. METHODS AF susceptibility and atrial function were assessed in male and female db/db mice and age-matched wildtype littermates. Electrophysiological studies were conducted in vivo using intracardiac electrophysiology and programmed stimulation. Atrial electrophysiology was also investigated in isolated atrial preparations using high-resolution optical mapping and in isolated atrial myocytes using patch-clamping. Molecular biology studies were performed using quantitative polymerase chain reaction and western blotting. Atrial fibrosis was assessed using histology. RESULTS db/db mice were highly susceptible to AF in association with reduced atrial conduction velocity, action potential duration prolongation, and increased heterogeneity in repolarization in left and right atria. In db/db mice, atrial K+ currents, including the transient outward current (Ito) and the ultrarapid delayed rectifier current (IKur), were reduced. The reduction in Ito occurred in association with reductions in Kcnd2 mRNA expression and KV4.2 protein levels. The reduction in IKur was not related to gene or protein expression changes. Interstitial atrial fibrosis was increased in db/db mice. CONCLUSION Our study demonstrates that increased susceptibility to AF in db/db mice occurs in association with impaired electrical conduction as well as electrical and structural remodeling of the atria.
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Affiliation(s)
- Loryn J Bohne
- Libin Cardiovascular Institute, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Hailey J Jansen
- Libin Cardiovascular Institute, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Irene Daniel
- Libin Cardiovascular Institute, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Tristan W Dorey
- Libin Cardiovascular Institute, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Motahareh Moghtadaei
- Libin Cardiovascular Institute, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Darrell D Belke
- Libin Cardiovascular Institute, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Martin Ezeani
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Robert A Rose
- Libin Cardiovascular Institute, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
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24
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Dorey TW, Moghtadaei M, Rose RA. Altered heart rate variability in angiotensin II–mediated hypertension is associated with impaired autonomic nervous system signaling and intrinsic sinoatrial node dysfunction. Heart Rhythm 2020; 17:1360-1370. [DOI: 10.1016/j.hrthm.2020.03.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 03/16/2020] [Indexed: 10/24/2022]
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25
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Chakraborty P, Rose RA, Nair K, Downar E, Nanthakumar K. The rationale for repurposing funny current inhibition for management of ventricular arrhythmia. Heart Rhythm 2020; 18:130-137. [PMID: 32738405 DOI: 10.1016/j.hrthm.2020.07.031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 07/14/2020] [Accepted: 07/25/2020] [Indexed: 11/26/2022]
Abstract
Management of ventricular arrhythmia in structural heart disease is complicated by the toxicity of the limited antiarrhythmic options available. In others, proarrhythmia and deleterious hemodynamic and noncardiac effects prevent practical use. This necessitates new thinking in therapeutic agents for ventricular arrhythmia in structural heart disease. Ivabradine, a funny current (If) inhibitor, has proven safety in heart failure, angina, and inappropriate sinus tachycardia. Although it is commonly known that funny channels are primarily expressed in the sinoatrial node, atrioventricular node, and conducting system of the ventricle, ivabradine is known to exert effects on metabolism, ion homeostasis, and membrane electrophysiology of remodeled ventricular myocardium. This review considers novel concepts and evidence from clinical and experimental studies regarding this paradigm, with a potential role of ivabradine in ventricular arrhythmia.
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Affiliation(s)
- Praloy Chakraborty
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada; University Health Network, Toronto, Ontario, Canada
| | - Robert A Rose
- Libin Cardiovascular Institute of Alberta, An entity of the University of Calgary and Alberta Health Services, Calgary, Alberta, Canada
| | - Krishnakumar Nair
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada; University Health Network, Toronto, Ontario, Canada
| | - Eugene Downar
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada; University Health Network, Toronto, Ontario, Canada
| | - Kumaraswamy Nanthakumar
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada; University Health Network, Toronto, Ontario, Canada.
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26
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Abstract
Atrial fibrillation (AF) is prevalent in common conditions and acquired forms of heart disease, including diabetes mellitus (DM), hypertension, cardiac hypertrophy, and heart failure. AF is also prevalent in aging. Although acquired heart disease is common in aging individuals, age is also an independent risk factor for AF. Importantly, not all individuals age at the same rate. Rather, individuals of the same chronological age can vary in health status from fit to frail. Frailty can be quantified using a frailty index, which can be used to assess heterogeneity in individuals of the same chronological age. AF is thought to occur in association with electrical remodeling due to changes in ion channel expression or function as well as structural remodeling due to fibrosis, myocyte hypertrophy, or adiposity. These forms of remodeling can lead to triggered activity and electrical re-entry, which are fundamental mechanisms of AF initiation and maintenance. Nevertheless, the underlying determinants of electrical and structural remodeling are distinct in different conditions and disease states. In this focused review, we consider the factors leading to atrial electrical and structural remodeling in human patients and animal models of acquired cardiovascular disease or associated risk factors. Our goal is to identify similarities and differences in the cellular and molecular bases for atrial electrical and structural remodeling in conditions including DM, hypertension, hypertrophy, heart failure, aging, and frailty.
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Affiliation(s)
- Hailey J Jansen
- Department of Cardiac Sciences, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Physiology and Pharmacology, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Loryn J Bohne
- Department of Cardiac Sciences, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Physiology and Pharmacology, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Anne M Gillis
- Department of Cardiac Sciences, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Robert A Rose
- Department of Cardiac Sciences, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Physiology and Pharmacology, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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27
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MacDonald EA, Rose RA, Quinn TA. Neurohumoral Control of Sinoatrial Node Activity and Heart Rate: Insight From Experimental Models and Findings From Humans. Front Physiol 2020; 11:170. [PMID: 32194439 PMCID: PMC7063087 DOI: 10.3389/fphys.2020.00170] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 02/13/2020] [Indexed: 12/22/2022] Open
Abstract
The sinoatrial node is perhaps one of the most important tissues in the entire body: it is the natural pacemaker of the heart, making it responsible for initiating each-and-every normal heartbeat. As such, its activity is heavily controlled, allowing heart rate to rapidly adapt to changes in physiological demand. Control of sinoatrial node activity, however, is complex, occurring through the autonomic nervous system and various circulating and locally released factors. In this review we discuss the coupled-clock pacemaker system and how its manipulation by neurohumoral signaling alters heart rate, considering the multitude of canonical and non-canonical agents that are known to modulate sinoatrial node activity. For each, we discuss the principal receptors involved and known intracellular signaling and protein targets, highlighting gaps in our knowledge and understanding from experimental models and human studies that represent areas for future research.
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Affiliation(s)
- Eilidh A MacDonald
- Department of Physiology and Biophysics, Dalhousie University, Halifax, NS, Canada
| | - Robert A Rose
- Cumming School of Medicine, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada
| | - T Alexander Quinn
- Department of Physiology and Biophysics, Dalhousie University, Halifax, NS, Canada.,School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada
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28
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Mackasey M, Jansen HJ, Moghtadaei M, Rose RA. Natriuretic Peptide Receptor-C Mitigates Angiotensin II Induced Fibrosis in the Atria and Sinoatrial Node. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.3108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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29
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Dorey TW, Moghtadaei M, Kirkby A, Rose RA. Intrinsic Sinoatrial Node Dysfunction Impairs Autonomic Regulation of Heart Rate Variability in Hypertensive Heart Disease. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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30
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Bohne LJ, Jansen HJ, Moghtadaei M, Rose RA. Electrical Remodelling Contributes to Atrial Fibrillation in Type 2 Diabetes Mellitus. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.1997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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31
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Liu Y, Jansen HJ, Rose RA. Impaired Parasympathetic Nervous System Regulation of Heart Rate and Sinoatrial Node Function in Type 2 Diabetes Mellitus. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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32
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Abstract
The electrophysiological properties of atrial myocytes importantly affect overall cardiac function. Alterations in the underlying ionic currents responsible for the action potential can cause pro-arrhythmic substrates that underlie arrhythmias, such as atrial fibrillation, which are highly prevalent in many conditions and disease states. Isolating adult mouse atrial cardiomyocytes for use in patch-clamp experiments has greatly advanced our knowledge and understanding of the cellular electrophysiology in the healthy atrial myocardium and in the setting of atrial pathophysiology. In addition, studies using genetic mouse models have elucidated the role of a vast array of proteins in regulating atrial electrophysiology. Here we provide a detailed protocol for the isolation of cardiomyocytes from the atrial appendages of adult mice using a combination of enzymatic digestion and mechanical dissociation of these tissues. This approach consistently and reliably yields isolated atrial cardiomyocytes that can then be used to characterize cellular electrophysiology by measuring action potentials and ionic currents in patch-clamp experiments under a number of experimental conditions.
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Affiliation(s)
- Hailey J Jansen
- Libin Cardiovascular Institute of Alberta, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary
| | - Robert A Rose
- Libin Cardiovascular Institute of Alberta, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary;
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33
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Bohne LJ, Johnson D, Rose RA, Wilton SB, Gillis AM. The Association Between Diabetes Mellitus and Atrial Fibrillation: Clinical and Mechanistic Insights. Front Physiol 2019; 10:135. [PMID: 30863315 PMCID: PMC6399657 DOI: 10.3389/fphys.2019.00135] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 02/04/2019] [Indexed: 01/16/2023] Open
Abstract
A number of clinical studies have reported that diabetes mellitus (DM) is an independent risk factor for Atrial fibrillation (AF). After adjustment for other known risk factors including age, sex, and cardiovascular risk factors, DM remains a significant if modest risk factor for development of AF. The mechanisms underlying the increased susceptibility to AF in DM are incompletely understood, but are thought to involve electrical, structural, and autonomic remodeling in the atria. Electrical remodeling in DM may involve alterations in gap junction function that affect atrial conduction velocity due to changes in expression or localization of connexins. Electrical remodeling can also occur due to changes in atrial action potential morphology in association with changes in ionic currents, such as sodium or potassium currents, that can affect conduction velocity or susceptibility to triggered activity. Structural remodeling in DM results in atrial fibrosis, which can alter conduction patterns and susceptibility to re-entry in the atria. In addition, increases in atrial adipose tissue, especially in Type II DM, can lead to disruptions in atrial conduction velocity or conduction patterns that may affect arrhythmogenesis. Whether the insulin resistance in type II DM activates unique intracellular signaling pathways independent of obesity requires further investigation. In addition, the relationship between incident AF and glycemic control requires further study.
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Affiliation(s)
- Loryn J Bohne
- Department of Cardiac Sciences and Department of Physiology and Pharmacology, University of Calgary and Libin Cardiovascular Institute of Alberta, Calgary, AB, Canada
| | - Dustin Johnson
- Department of Cardiac Sciences and Department of Physiology and Pharmacology, University of Calgary and Libin Cardiovascular Institute of Alberta, Calgary, AB, Canada
| | - Robert A Rose
- Department of Cardiac Sciences and Department of Physiology and Pharmacology, University of Calgary and Libin Cardiovascular Institute of Alberta, Calgary, AB, Canada
| | - Stephen B Wilton
- Department of Cardiac Sciences and Department of Physiology and Pharmacology, University of Calgary and Libin Cardiovascular Institute of Alberta, Calgary, AB, Canada
| | - Anne M Gillis
- Department of Cardiac Sciences and Department of Physiology and Pharmacology, University of Calgary and Libin Cardiovascular Institute of Alberta, Calgary, AB, Canada
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34
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Ayaz O, Banga S, Heinze-Milne S, Rose RA, Pyle WG, Howlett SE. Long-term testosterone deficiency modifies myofilament and calcium-handling proteins and promotes diastolic dysfunction in the aging mouse heart. Am J Physiol Heart Circ Physiol 2019; 316:H768-H780. [PMID: 30657724 DOI: 10.1152/ajpheart.00471.2018] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The impact of long-term gonadectomy (GDX) on cardiac contractile function was explored in the setting of aging. Male mice were subjected to bilateral GDX or sham operation (4 wk) and investigated at 16-18 mo of age. Ventricular myocytes were field stimulated (2 Hz, 37°C). Peak Ca2+ transients (fura 2) and contractions were similar in GDX and sham-operated mice, although Ca2+ transients (50% decay time: 45.2 ± 2.3 vs. 55.6 ± 3.1 ms, P < 0.05) and contractions (time constant of relaxation: 39.1 ± 3.2 vs. 69.5 ± 9.3 ms, P < 0.05) were prolonged in GDX mice. Action potential duration was increased in myocytes from GDX mice, but this did not account for prolonged responses, as Ca2+ transient decay was slow even when cells from GDX mice were voltage clamped with simulated "sham" action potentials. Western blots of proteins involved in Ca2+ sequestration and efflux showed that Na+/Ca2+ exchanger and sarco(endo)plasmic reticulum Ca2+-ATPase type 2 protein levels were unaffected, whereas phospholamban was dramatically higher in ventricles from aging GDX mice (0.24 ± 0.02 vs. 0.86 ± 0.13, P < 0.05). Myofilament Ca2+ sensitivity at physiological Ca2+ was similar, but phosphorylation of essential myosin light chain 1 was reduced by ≈50% in ventricles from aging GDX mice. M-mode echocardiography showed no change in systolic function (e.g., ejection fraction). Critically, pulse-wave Doppler echocardiography showed that GDX slowed isovolumic relaxation time (12.9 ± 0.9 vs. 16.9 ± 1.0 ms, P < 0.05), indicative of diastolic dysfunction. Thus, dysregulation of intracellular Ca2+ and myofilament dysfunction contribute to deficits in contraction in hearts from testosterone-deficient aging mice. This suggests that low testosterone helps promote diastolic dysfunction in the aging heart. NEW & NOTEWORTHY The influence of long-term gonadectomy on contractile function was examined in aging male hearts. Gonadectomy slowed the decay of Ca2+ transients and contractions in ventricular myocytes and slowed isovolumic relaxation time, demonstrating diastolic dysfunction. Underlying mechanisms included Ca2+ dysregulation, elevated phospholamban protein levels, and hypophosphorylation of a myofilament protein, essential myosin light chain. Testosterone deficiency led to intracellular Ca2+ dysregulation and myofilament dysfunction, which may facilitate diastolic dysfunction in the setting of aging.
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Affiliation(s)
- Omar Ayaz
- Department of Pharmacology, Dalhousie University , Halifax, Nova Scotia , Canada
| | - Shubham Banga
- Department of Pharmacology, Dalhousie University , Halifax, Nova Scotia , Canada
| | - Stefan Heinze-Milne
- Department of Pharmacology, Dalhousie University , Halifax, Nova Scotia , Canada
| | - Robert A Rose
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary , Calgary, Alberta , Canada
| | - W Glen Pyle
- Department of Biomedical Sciences, University of Guelph , Guelph, Ontario , Canada
| | - Susan E Howlett
- Department of Pharmacology, Dalhousie University , Halifax, Nova Scotia , Canada.,Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary , Calgary, Alberta , Canada
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35
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Jansen HJ, Mackasey M, Moghtadaei M, Liu Y, Kaur J, Egom EE, Tuomi JM, Rafferty SA, Kirkby AW, Rose RA. NPR-C (Natriuretic Peptide Receptor-C) Modulates the Progression of Angiotensin II–Mediated Atrial Fibrillation and Atrial Remodeling in Mice. Circ Arrhythm Electrophysiol 2019; 12:e006863. [DOI: 10.1161/circep.118.006863] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Hailey J. Jansen
- Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta (H.J.J., M. Mackasey, Y.L., J.K., A.W.K., R.A.R.), Cumming School of Medicine, University of Calgary, Alberta
- Department of Physiology and Pharmacology (H.J.J., M. Mackasey, Y.L., J.K., A.W.K., R.A.R.), Cumming School of Medicine, University of Calgary, Alberta
| | - Martin Mackasey
- Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta (H.J.J., M. Mackasey, Y.L., J.K., A.W.K., R.A.R.), Cumming School of Medicine, University of Calgary, Alberta
- Department of Physiology and Pharmacology (H.J.J., M. Mackasey, Y.L., J.K., A.W.K., R.A.R.), Cumming School of Medicine, University of Calgary, Alberta
| | - Motahareh Moghtadaei
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia (M. Moghtadaei, E.E.E., S.A.R.)
| | - Yingjie Liu
- Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta (H.J.J., M. Mackasey, Y.L., J.K., A.W.K., R.A.R.), Cumming School of Medicine, University of Calgary, Alberta
- Department of Physiology and Pharmacology (H.J.J., M. Mackasey, Y.L., J.K., A.W.K., R.A.R.), Cumming School of Medicine, University of Calgary, Alberta
| | - Jaspreet Kaur
- Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta (H.J.J., M. Mackasey, Y.L., J.K., A.W.K., R.A.R.), Cumming School of Medicine, University of Calgary, Alberta
- Department of Physiology and Pharmacology (H.J.J., M. Mackasey, Y.L., J.K., A.W.K., R.A.R.), Cumming School of Medicine, University of Calgary, Alberta
| | - Emmanuel E. Egom
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia (M. Moghtadaei, E.E.E., S.A.R.)
| | - Jari M. Tuomi
- Department of Medicine, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada (J.M.T.)
| | - Sara A. Rafferty
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia (M. Moghtadaei, E.E.E., S.A.R.)
| | - Adam W. Kirkby
- Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta (H.J.J., M. Mackasey, Y.L., J.K., A.W.K., R.A.R.), Cumming School of Medicine, University of Calgary, Alberta
- Department of Physiology and Pharmacology (H.J.J., M. Mackasey, Y.L., J.K., A.W.K., R.A.R.), Cumming School of Medicine, University of Calgary, Alberta
| | - Robert A. Rose
- Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta (H.J.J., M. Mackasey, Y.L., J.K., A.W.K., R.A.R.), Cumming School of Medicine, University of Calgary, Alberta
- Department of Physiology and Pharmacology (H.J.J., M. Mackasey, Y.L., J.K., A.W.K., R.A.R.), Cumming School of Medicine, University of Calgary, Alberta
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Jansen HJ, Egom EE, Tuomi JM, Rafferty SA, Rose RA. The role of Natriuretic Peptide Receptor C in atrial electrophysiological remodelling in hypertensive heart disease. J Mol Cell Cardiol 2018. [DOI: 10.1016/j.yjmcc.2018.07.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Jansen HJ, Mackasey M, Moghtadaei M, Belke DD, Egom EE, Tuomi JM, Rafferty SA, Kirkby AW, Rose RA. Distinct patterns of atrial electrical and structural remodeling in angiotensin II mediated atrial fibrillation. J Mol Cell Cardiol 2018; 124:12-25. [PMID: 30273558 DOI: 10.1016/j.yjmcc.2018.09.011] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 09/25/2018] [Accepted: 09/26/2018] [Indexed: 01/14/2023]
Abstract
Atrial fibrillation (AF) is prevalent in hypertension and elevated angiotensin II (Ang II); however, the mechanisms by which Ang II leads to AF are poorly understood. Here, we investigated the basis for this in mice treated with Ang II or saline for 3 weeks. Ang II treatment increased susceptibility to AF compared to saline controls in association with increases in P wave duration and atrial effective refractory period, as well as reductions in right and left atrial conduction velocity. Patch-clamp studies demonstrate that action potential (AP) duration was prolonged in right atrial myocytes from Ang II treated mice in association with a reduction in repolarizing K+ currents. In contrast, APs in left atrial myocytes from Ang II treated mice showed reductions in upstroke velocity and overshoot, as well as greater prolongations in AP duration. Ang II reduced Na+ current (INa) in the left, but not the right atrium. This reduction in INa was reversible following inhibition of protein kinase C (PKC) and PKCα expression was increased selectively in the left atrium in Ang II treated mice. The transient outward K+ current (Ito) showed larger reductions in the left atrium in association with a shift in the voltage dependence of activation. Finally, Ang II caused fibrosis throughout the atria in association with changes in collagen expression and regulators of the extracellular matrix. This study demonstrates that hypertension and elevated Ang II cause distinct patterns of electrical and structural remodeling in the right and left atria that collectively create a substrate for AF.
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Affiliation(s)
- Hailey J Jansen
- Libin Cardiovascular Institute of Alberta, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Martin Mackasey
- Libin Cardiovascular Institute of Alberta, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Motahareh Moghtadaei
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Darrell D Belke
- Libin Cardiovascular Institute of Alberta, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Emmanuel E Egom
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Jari M Tuomi
- Department of Medicine, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada
| | - Sara A Rafferty
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Adam W Kirkby
- Libin Cardiovascular Institute of Alberta, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Robert A Rose
- Libin Cardiovascular Institute of Alberta, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
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Egom EEA, Feridooni T, Pharithi RB, Khan B, Shiwani HA, Maher V, El Hiani Y, Rose RA, Pasumarthi KBS, Ribama HA. Erratum: New insights and new hope for pulmonary arterial hypertension: natriuretic peptides clearance receptor as a novel therapeutic target for a complex disease. Int J Physiol Pathophysiol Pharmacol 2017; 9:164. [PMID: 29218116 PMCID: PMC5698694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Accepted: 10/03/2017] [Indexed: 06/07/2023]
Abstract
[This corrects the article on p. 112 in vol. 9, PMID: 28951773.].
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Affiliation(s)
- Emmanuel Eroume-A Egom
- Egom Clinical & Translational Research Services Ltd.Dartmouth, NS B3H 3H3, Canada
- Department of Cardiology, The Adelaide and Meath HospitalTallaght, Dublin, Ireland
| | - Tiam Feridooni
- Department of Pharmacology, Dalhousie UniversityHalifax, Nova Scotia, Canada
| | - Rebabonye B Pharithi
- Department of Cardiology, The Adelaide and Meath HospitalTallaght, Dublin, Ireland
| | - Barkat Khan
- Department of Cardiology, The Adelaide and Meath HospitalTallaght, Dublin, Ireland
| | - Haaris A Shiwani
- Department of Cardiology, The Adelaide and Meath HospitalTallaght, Dublin, Ireland
| | - Vincent Maher
- Department of Cardiology, The Adelaide and Meath HospitalTallaght, Dublin, Ireland
| | - Yassine El Hiani
- Department of Physiology and Biophysics, Dalhousie UniversityPO Box 15000, Halifax, NS, B3H 4R2, Canada
| | - Robert A Rose
- Libin Cardiovascular Institute of Alberta, University of CalgaryCalgary, Alberta, Canada
| | | | - Hilaire A Ribama
- Egom Clinical & Translational Research Services Ltd.Dartmouth, NS B3H 3H3, Canada
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Egom EEA, Feridooni T, Pharithi RB, Khan B, Shiwani HA, Maher V, El Hiani Y, Rose RA, Pasumarthi KBS, Ribama HA. New insights and new hope for pulmonary arterial hypertension: natriuretic peptides clearance receptor as a novel therapeutic target for a complex disease. Int J Physiol Pathophysiol Pharmacol 2017; 9:112-118. [PMID: 28951773 PMCID: PMC5592245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 06/18/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND Pulmonary Arterial Hypertension (PAH) is a deadly and disabling disease for which there is no marketed drug that addresses the underlying disease mechanism and targets to cure patients. The lack of understanding of the disease mechanism represents the main challenges in developing curative therapies. We here report, for the first time, that mice lacking natriuretic peptides clearance receptor develop PAH. METHODS AND RESULTS Initial studies assessed cardiac structure and function in NPR-C+/+ (wild type) and age matched, littermate NPR-C-/- mice by echocardiography. Mice lacking NPR-C had right atrial dilation, tricuspid regurgitation as well as echocardiographic signs of right ventricular pressure overload, including flattening and paradoxical bulging of the septum into the left ventricle during systole, and hypertrophy of the right ventricular free wall. Among the 10 NPR-C-/- mice aged between 12 and 20 weeks studied, 8 showed the above typical echocardiographic features of PAH [80%, 95% CI: (0.4439-0.9748)], and only one had pericardial effusion [10%, 95% CI: (0.0025-0.4450)], finding that has a prognostic significance in subjects affected by this clinical entity. To confirm the presence of increased right ventricular systolic pressure (RVSP) among NPR-C-/- mice, right heart catheterization was performed. Strikingly, RVSP was significantly elevated in NPR-C-/- mice compared to their age matched, littermate NPR-C+/+ mice, at baseline (21.95±0.56 mmHg vs. 5.3±0.6 mmHg, respectively (P<0.001)). CONCLUSION The above results suggest that NPR-C-mediated signalling pathways play a critical role in the development of PAH, indicating that NPR-C is an important protective receptor in the heart rather than just being a clearance receptor.
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Affiliation(s)
- Emmanuel Eroume-A Egom
- Egom Clinical & Translational Research Services Ltd.Dartmouth, NS B3H 3H3, Canada
- Department of Cardiology, The Adelaide and Meath HospitalTallaght, Dublin, Ireland
| | - Tiam Feridooni
- Department of Pharmacology, Dalhousie UniversityHalifax, Nova Scotia, Canada
| | - Rebabonye B Pharithi
- Department of Cardiology, The Adelaide and Meath HospitalTallaght, Dublin, Ireland
| | - Barkat Khan
- Department of Cardiology, The Adelaide and Meath HospitalTallaght, Dublin, Ireland
| | - Haaris A Shiwani
- Department of Cardiology, The Adelaide and Meath HospitalTallaght, Dublin, Ireland
| | - Vincent Maher
- Department of Cardiology, The Adelaide and Meath HospitalTallaght, Dublin, Ireland
| | - Yassine El Hiani
- Department of Physiology and Biophysics, Dalhousie UniversityPO Box 15000, Halifax, NS, B3H 4R2, Canada
| | - Robert A Rose
- Libin Cardiovascular Institute of Alberta, University of CalgaryCalgary, Alberta, Canada
| | | | - Hilaire A Ribama
- Egom Clinical & Translational Research Services Ltd.Dartmouth, NS B3H 3H3, Canada
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Parks RJ, Bogachev O, Mackasey M, Ray G, Rose RA, Howlett SE. The impact of ovariectomy on cardiac excitation-contraction coupling is mediated through cAMP/PKA-dependent mechanisms. J Mol Cell Cardiol 2017; 111:51-60. [PMID: 28778766 DOI: 10.1016/j.yjmcc.2017.07.118] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 07/11/2017] [Accepted: 07/28/2017] [Indexed: 12/18/2022]
Abstract
Ovariectomy (OVX) promotes sarcoplasmic reticulum (SR) Ca2+ overload in ventricular myocytes. We hypothesized that the cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) pathway contributes to this Ca2+ dysregulation. Myocytes were isolated from adult female C57BL/6 mice following either OVX or sham surgery (surgery at ≈1mos). Contractions, Ca2+ concentrations (fura-2) and ionic currents were measured simultaneously (37°C, 2Hz) in voltage-clamped myocytes. Intracellular cAMP levels were determined with an enzyme immunoassay; phosphodiesterase (PDE) and adenylyl cyclase (AC) isoform expression was examined with qPCR. Ca2+ currents were similar in myocytes from sham and OVX mice but Ca2+ transients, excitation-contraction (EC)-coupling gain, SR content and contractions were larger in OVX than sham cells. To determine if the cAMP/PKA pathway mediated OVX-induced alterations in EC-coupling, cardiomyocytes were incubated with the PKA inhibitor H-89 (2μM), which abolished baseline differences. While basal intracellular cAMP did not differ, levels were higher in OVX than sham in the presence of a non-selective PDE inhibitor (300μM IBMX), or an AC activator (10μM forskolin). This suggests the production of cAMP by AC and its breakdown by PDE were enhanced by OVX. Consistent with this, mRNA levels for both AC5 and PDE4A were higher in OVX in comparison to sham. Differences in Ca2+ homeostasis and contractions were abolished when sham and OVX cells were dialyzed with patch pipettes containing the same concentration of 8-bromoadenosine-cAMP (50μM). Interestingly, selective inhibition of PDE4 increased Ca2+ current only in OVX cells. Together, these findings suggest that estrogen suppresses SR Ca2+ release and that this is regulated, at least in part, by the cAMP/PKA pathway. These changes in the cAMP/PKA pathway may promote Ca2+ dysregulation and cardiovascular disease when ovarian estrogen levels fall. These results advance our understanding of female-specific cardiomyocyte mechanisms that may affect responses to therapeutic interventions in older women.
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Affiliation(s)
- Randi J Parks
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, 5850 College Street, P.O. Box 15000, Halifax B3H 4R2, Nova Scotia, Canada.
| | - Oleg Bogachev
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, 5850 College Street, P.O. Box 15000, Halifax B3H 4R2, Nova Scotia, Canada.
| | - Martin Mackasey
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, 5850 College Street, P.O. Box 15000, Halifax B3H 4R2, Nova Scotia, Canada.
| | - Gibanananda Ray
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, 5850 College Street, P.O. Box 15000, Halifax B3H 4R2, Nova Scotia, Canada.
| | - Robert A Rose
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, 5850 College Street, P.O. Box 15000, Halifax B3H 4R2, Nova Scotia, Canada.
| | - Susan E Howlett
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, 5850 College Street, P.O. Box 15000, Halifax B3H 4R2, Nova Scotia, Canada; Department of Medicine (Geriatric Medicine), Faculty of Medicine, Dalhousie University, 5850 College Street, P.O. Box 15000, Halifax B3H 4R2, Nova Scotia, Canada.
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MacDonald EA, Stoyek MR, Rose RA, Quinn TA. Intrinsic regulation of sinoatrial node function and the zebrafish as a model of stretch effects on pacemaking. Prog Biophys Mol Biol 2017; 130:198-211. [PMID: 28743586 DOI: 10.1016/j.pbiomolbio.2017.07.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 07/17/2017] [Accepted: 07/21/2017] [Indexed: 12/18/2022]
Abstract
Excitation of the heart occurs in a specialised region known as the sinoatrial node (SAN). Tight regulation of SAN function is essential for the maintenance of normal heart rhythm and the response to (patho-)physiological changes. The SAN is regulated by extrinsic (central nervous system) and intrinsic (neurons, peptides, mechanics) factors. The positive chronotropic response to stretch in particular is essential for beat-by-beat adaptation to changes in hemodynamic load. Yet, the mechanism of this stretch response is unknown, due in part to the lack of an appropriate experimental model for targeted investigations. We have been investigating the zebrafish as a model for the study of intrinsic regulation of SAN function. In this paper, we first briefly review current knowledge of the principal components of extrinsic and intrinsic SAN regulation, derived primarily from experiments in mammals, followed by a description of the zebrafish as a novel experimental model for studies of intrinsic SAN regulation. This mini-review is followed by an original investigation of the response of the zebrafish isolated SAN to controlled stretch. Stretch causes an immediate and continuous increase in beating rate in the zebrafish isolated SAN. This increase reaches a maximum part way through a period of sustained stretch, with the total change dependent on the magnitude and direction of stretch. This is comparable to what occurs in isolated SAN from most mammals (including human), suggesting that the zebrafish is a novel experimental model for the study of mechanisms involved in the intrinsic regulation of SAN function by mechanical effects.
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Affiliation(s)
- Eilidh A MacDonald
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Canada
| | - Matthew R Stoyek
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Canada
| | - Robert A Rose
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - T Alexander Quinn
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Canada; School of Biomedical Engineering, Dalhousie University, Halifax, Canada.
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42
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Feridooni HA, Kane AE, Ayaz O, Boroumandi A, Polidovitch N, Tsushima RG, Rose RA, Howlett SE. The impact of age and frailty on ventricular structure and function in C57BL/6J mice. J Physiol 2017; 595:3721-3742. [PMID: 28502095 DOI: 10.1113/jp274134] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 03/23/2017] [Indexed: 12/25/2022] Open
Abstract
KEY POINTS Heart size increases with age (called hypertrophy), and its ability to contract declines. However, these reflect average changes that may not be present, or present to the same extent, in all older individuals. That aging happens at different rates is well accepted clinically. People who are aging rapidly are frail and frailty is measured with a 'frailty index'. We quantified frailty with a validated mouse frailty index tool and evaluated the impacts of age and frailty on cardiac hypertrophy and contractile dysfunction. Hypertrophy increased with age, while contractions, calcium currents and calcium transients declined; these changes were graded by frailty scores. Overall health status, quantified as frailty, may promote maladaptive changes associated with cardiac aging and facilitate the development of diseases such as heart failure. To understand age-related changes in heart structure and function, it is essential to know both chronological age and the health status of the animal. ABSTRACT On average, cardiac hypertrophy and contractile dysfunction increase with age. Still, individuals age at different rates and their health status varies from fit to frail. We investigated the influence of frailty on age-dependent ventricular remodelling. Frailty was quantified as deficit accumulation in adult (≈7 months) and aged (≈27 months) C57BL/6J mice by adapting a validated frailty index (FI) tool. Hypertrophy and contractile function were evaluated in Langendorff-perfused hearts; cellular correlates/mechanisms were investigated in ventricular myocytes. FI scores increased with age. Mean cardiac hypertrophy increased with age, but values in the adult and aged groups overlapped. When plotted as a function of frailty, hypertrophy was graded by FI score (r = 0.67-0.55, P < 0.0003). Myocyte area also correlated positively with FI (r = 0.34, P = 0.03). Left ventricular developed pressure (LVDP) plus rates of pressure development (+dP/dt) and decay (-dP/dt) declined with age and this was graded by frailty (r = -0.51, P = 0.0007; r = -0.48, P = 0.002; r = -0.56, P = 0.0002 for LVDP, +dP/dt and -dP/dt). Smaller, slower contractions graded by FI score were also seen in ventricular myocytes. Contractile dysfunction in cardiomyocytes isolated from frail mice was attributable to parallel changes in underlying Ca2+ transients. These changes were not due to reduced sarcoplasmic reticulum stores, but were graded by smaller Ca2+ currents (r = -0.40, P = 0.008), lower gain (r = -0.37, P = 0.02) and reduced expression of Cav1.2 protein (r = -0.68, P = 0.003). These results show that cardiac hypertrophy and contractile dysfunction in naturally aging mice are graded by overall health and suggest that frailty, in addition to chronological age, can help explain heterogeneity in cardiac aging.
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Affiliation(s)
- H A Feridooni
- Department of Pharmacology, Dalhousie University, PO Box 15000, 5850 College St, B3H 4R2, Halifax, NS, Canada
| | - A E Kane
- Department of Pharmacology, Dalhousie University, PO Box 15000, 5850 College St, B3H 4R2, Halifax, NS, Canada
| | - O Ayaz
- Department of Pharmacology, Dalhousie University, PO Box 15000, 5850 College St, B3H 4R2, Halifax, NS, Canada
| | - A Boroumandi
- Department of Biology, Muscle Health Research Centre, York University, 4700 Keele St, Toronto, ON, Canada, M3J 1P3
| | - N Polidovitch
- Department of Biology, Muscle Health Research Centre, York University, 4700 Keele St, Toronto, ON, Canada, M3J 1P3
| | - R G Tsushima
- Department of Biology, Muscle Health Research Centre, York University, 4700 Keele St, Toronto, ON, Canada, M3J 1P3
| | - R A Rose
- Department of Physiology and Biophysics, Dalhousie University, PO Box 15000, 5850 College St, B3H 4R2, Halifax, NS, Canada
| | - S E Howlett
- Department of Pharmacology, Dalhousie University, PO Box 15000, 5850 College St, B3H 4R2, Halifax, NS, Canada.,Department of Medicine (Geriatric Medicine), Dalhousie University, PO Box 15000, 5850 College St, B3H 4R2, Halifax, NS, Canada
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Rockwood K, Blodgett JM, Theou O, Sun MH, Feridooni HA, Mitnitski A, Rose RA, Godin J, Gregson E, Howlett SE. A Frailty Index Based On Deficit Accumulation Quantifies Mortality Risk in Humans and in Mice. Sci Rep 2017; 7:43068. [PMID: 28220898 PMCID: PMC5318852 DOI: 10.1038/srep43068] [Citation(s) in RCA: 148] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 01/18/2017] [Indexed: 02/06/2023] Open
Abstract
Although many common diseases occur mostly in old age, the impact of ageing itself on disease risk and expression often goes unevaluated. To consider the impact of ageing requires some useful means of measuring variability in health in animals of the same age. In humans, this variability has been quantified by counting age-related health deficits in a frailty index. Here we show the results of extending that approach to mice. Across the life course, many important features of deficit accumulation are present in both species. These include gradual rates of deficit accumulation (slope = 0.029 in humans; 0.036 in mice), a submaximal limit (0.54 in humans; 0.44 in mice), and a strong relationship to mortality (1.05 [1.04–1.05] in humans; 1.15 [1.12–1.18] in mice). Quantifying deficit accumulation in individual mice provides a powerful new tool that can facilitate translation of research on ageing, including in relation to disease.
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Affiliation(s)
- K Rockwood
- Geriatric Medicine, Department of Medicine, Dalhousie University, Halifax, N.S., Canada
| | - J M Blodgett
- Geriatric Medicine, Department of Medicine, Dalhousie University, Halifax, N.S., Canada
| | - O Theou
- Geriatric Medicine, Department of Medicine, Dalhousie University, Halifax, N.S., Canada
| | - M H Sun
- Department of Pharmacology, Dalhousie University, Halifax, N.S., Canada
| | - H A Feridooni
- Department of Pharmacology, Dalhousie University, Halifax, N.S., Canada
| | - A Mitnitski
- Geriatric Medicine, Department of Medicine, Dalhousie University, Halifax, N.S., Canada
| | - R A Rose
- Department of Physiology &Biophysics, Dalhousie University, Halifax, N.S., Canada
| | - J Godin
- Geriatric Medicine, Department of Medicine, Dalhousie University, Halifax, N.S., Canada
| | - E Gregson
- Geriatric Medicine, Department of Medicine, Dalhousie University, Halifax, N.S., Canada
| | - S E Howlett
- Geriatric Medicine, Department of Medicine, Dalhousie University, Halifax, N.S., Canada.,Department of Pharmacology, Dalhousie University, Halifax, N.S., Canada
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Jansen HJ, Egom EE, Rafferty SA, Rose RA. Atrial Fibrillation in Hypertensive Heart Disease is Associated with Distinct Patterns of Electrical Remodeling in the Left and Right Atria. Biophys J 2017. [DOI: 10.1016/j.bpj.2016.11.1287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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45
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Moghtadaei M, Jansen HJ, Mackasey M, Rafferty SA, Bogachev O, Sapp JL, Howlett SE, Rose RA. The impacts of age and frailty on heart rate and sinoatrial node function. J Physiol 2016; 594:7105-7126. [PMID: 27598221 DOI: 10.1113/jp272979] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 08/24/2016] [Indexed: 12/19/2022] Open
Abstract
KEY POINTS Sinoatrial node (SAN) function declines with age; however, not all individuals age at the same rate and health status can vary from fit to frail. Frailty was quantified in young and aged mice using a non-invasive frailty index so that the impacts of age and frailty on heart rate and SAN function could be assessed. SAN function was impaired in aged mice due to alterations in electrical conduction, changes in SAN action potential morphology and fibrosis in the SAN. Changes in SAN function, electrical conduction, action potential morphology and fibrosis were correlated with, and graded by, frailty. This study shows that mice of the same chronological age have quantifiable differences in health status that impact heart rate and SAN function and that these differences in health status can be identified using our frailty index. ABSTRACT Sinoatrial node (SAN) dysfunction increases with age, although not all older adults are affected in the same way. This is because people age at different rates and individuals of the same chronological age vary in health status from very fit to very frail. Our objective was to determine the impacts of age and frailty on heart rate (HR) and SAN function using a new model of frailty in ageing mice. Frailty, which was quantified in young and aged mice using a frailty index (FI), was greater in aged vs. young mice. Intracardiac electrophysiology demonstrated that HR was reduced whereas SAN recovery time (SNRT) was prolonged in aged mice; however, both parameters showed heteroscedasticity suggesting differences in health status among mice of similar chronological age. Consistent with this, HR and corrected SNRT were correlated with, and graded by, FI score. Optical mapping of the SAN demonstrated that conduction velocity (CV) was reduced in aged hearts in association with reductions in diastolic depolarization (DD) slope and action potential (AP) duration. In agreement with in vivo results, SAN CV, DD slope and AP durations all correlated with FI score. Finally, SAN dysfunction in aged mice was associated with increased interstitial fibrosis and alterations in expression of matrix metalloproteinases, which also correlated with frailty. These findings demonstrate that age-related SAN dysfunction occurs in association with electrical and structural remodelling and that frailty is a critical determinant of health status of similarly aged animals that correlates with changes in HR and SAN function.
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Affiliation(s)
- Motahareh Moghtadaei
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Hailey J Jansen
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Martin Mackasey
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Sara A Rafferty
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Oleg Bogachev
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - John L Sapp
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.,Division of Cardiology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Susan E Howlett
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Robert A Rose
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.,School of Biomedical Engineering, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
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Moghtadaei M, Polina I, Rose RA. Electrophysiological effects of natriuretic peptides in the heart are mediated by multiple receptor subtypes. Progress in Biophysics and Molecular Biology 2016; 120:37-49. [DOI: 10.1016/j.pbiomolbio.2015.12.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 11/25/2015] [Accepted: 12/02/2015] [Indexed: 12/13/2022]
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Hua R, MacLeod SL, Polina I, Moghtadaei M, Jansen HJ, Bogachev O, O’Blenes SB, Sapp JL, Legare JF, Rose RA. Effects of Wild-Type and Mutant Forms of Atrial Natriuretic Peptide on Atrial Electrophysiology and Arrhythmogenesis. Circ Arrhythm Electrophysiol 2015; 8:1240-54. [DOI: 10.1161/circep.115.002896] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 07/10/2015] [Indexed: 11/16/2022]
Abstract
Background—
Atrial natriuretic peptide (ANP) is a hormone with numerous beneficial cardiovascular effects. Recently, a mutation in the ANP gene, which results in the generation of a mutant form of ANP (mANP), was identified and shown to cause atrial fibrillation in people. The mechanism(s) through which mANP causes atrial fibrillation is unknown. Our objective was to compare the effects of wild-type ANP and mANP on atrial electrophysiology in mice and humans.
Methods and Results—
Action potentials (APs), L-type Ca
2+
currents (
I
Ca,L
), and Na
+
current were recorded in atrial myocytes from wild-type or natriuretic peptide receptor C knockout (NPR-C
−/−
) mice. In mice, ANP and mANP (10–100 nmol/L) had opposing effects on atrial myocyte AP morphology and
I
Ca,L
. ANP increased AP upstroke velocity (
V
max
), AP duration, and
I
Ca,L
similarly in wild-type and NPR-C
−/−
myocytes. In contrast, mANP decreased
V
max
, AP duration, and
I
Ca,L
, and these effects were completely absent in NPR-C
−/−
myocytes. ANP and mANP also had opposing effects on
I
Ca,L
in human atrial myocytes. In contrast, neither ANP nor mANP had any effect on Na
+
current in mouse atrial myocytes. Optical mapping studies in mice demonstrate that ANP sped electric conduction in the atria, whereas mANP did the opposite and slowed atrial conduction. Atrial pacing in the presence of mANP induced arrhythmias in 62.5% of hearts, whereas treatment with ANP completely prevented the occurrence of arrhythmias.
Conclusions—
These findings provide mechanistic insight into how mANP causes atrial fibrillation and demonstrate that wild-type ANP is antiarrhythmic.
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Affiliation(s)
- Rui Hua
- From the Department of Physiology and Biophysics (R.H., S.L.M., I.P., M.M., H.J.J., O.B., S.B.O., J.L.S., R.A.R.), IWK Health Centre (S.B.O.), Department of Surgery (S.B.O., J.-F.L.), Division of Cardiology (J.L.S.), School of Biomedical Engineering (R.A.R.), Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Sarah L. MacLeod
- From the Department of Physiology and Biophysics (R.H., S.L.M., I.P., M.M., H.J.J., O.B., S.B.O., J.L.S., R.A.R.), IWK Health Centre (S.B.O.), Department of Surgery (S.B.O., J.-F.L.), Division of Cardiology (J.L.S.), School of Biomedical Engineering (R.A.R.), Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Iuliia Polina
- From the Department of Physiology and Biophysics (R.H., S.L.M., I.P., M.M., H.J.J., O.B., S.B.O., J.L.S., R.A.R.), IWK Health Centre (S.B.O.), Department of Surgery (S.B.O., J.-F.L.), Division of Cardiology (J.L.S.), School of Biomedical Engineering (R.A.R.), Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Motahareh Moghtadaei
- From the Department of Physiology and Biophysics (R.H., S.L.M., I.P., M.M., H.J.J., O.B., S.B.O., J.L.S., R.A.R.), IWK Health Centre (S.B.O.), Department of Surgery (S.B.O., J.-F.L.), Division of Cardiology (J.L.S.), School of Biomedical Engineering (R.A.R.), Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Hailey J. Jansen
- From the Department of Physiology and Biophysics (R.H., S.L.M., I.P., M.M., H.J.J., O.B., S.B.O., J.L.S., R.A.R.), IWK Health Centre (S.B.O.), Department of Surgery (S.B.O., J.-F.L.), Division of Cardiology (J.L.S.), School of Biomedical Engineering (R.A.R.), Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Oleg Bogachev
- From the Department of Physiology and Biophysics (R.H., S.L.M., I.P., M.M., H.J.J., O.B., S.B.O., J.L.S., R.A.R.), IWK Health Centre (S.B.O.), Department of Surgery (S.B.O., J.-F.L.), Division of Cardiology (J.L.S.), School of Biomedical Engineering (R.A.R.), Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Stacy B. O’Blenes
- From the Department of Physiology and Biophysics (R.H., S.L.M., I.P., M.M., H.J.J., O.B., S.B.O., J.L.S., R.A.R.), IWK Health Centre (S.B.O.), Department of Surgery (S.B.O., J.-F.L.), Division of Cardiology (J.L.S.), School of Biomedical Engineering (R.A.R.), Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - John L. Sapp
- From the Department of Physiology and Biophysics (R.H., S.L.M., I.P., M.M., H.J.J., O.B., S.B.O., J.L.S., R.A.R.), IWK Health Centre (S.B.O.), Department of Surgery (S.B.O., J.-F.L.), Division of Cardiology (J.L.S.), School of Biomedical Engineering (R.A.R.), Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Jean-Francois Legare
- From the Department of Physiology and Biophysics (R.H., S.L.M., I.P., M.M., H.J.J., O.B., S.B.O., J.L.S., R.A.R.), IWK Health Centre (S.B.O.), Department of Surgery (S.B.O., J.-F.L.), Division of Cardiology (J.L.S.), School of Biomedical Engineering (R.A.R.), Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Robert A. Rose
- From the Department of Physiology and Biophysics (R.H., S.L.M., I.P., M.M., H.J.J., O.B., S.B.O., J.L.S., R.A.R.), IWK Health Centre (S.B.O.), Department of Surgery (S.B.O., J.-F.L.), Division of Cardiology (J.L.S.), School of Biomedical Engineering (R.A.R.), Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
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Krishnaswamy PS, Egom EE, Moghtadaei M, Jansen HJ, Azer J, Bogachev O, Mackasey M, Robbins C, Rose RA. Altered parasympathetic nervous system regulation of the sinoatrial node in Akita diabetic mice. J Mol Cell Cardiol 2015; 82:125-35. [DOI: 10.1016/j.yjmcc.2015.02.024] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 02/21/2015] [Accepted: 02/26/2015] [Indexed: 11/26/2022]
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Rose RA, Byler D, Eastman JR, Fleishman E, Geller G, Goetz S, Guild L, Hamilton H, Hansen M, Headley R, Hewson J, Horning N, Kaplin BA, Laporte N, Leidner A, Leimgruber P, Morisette J, Musinsky J, Pintea L, Prados A, Radeloff VC, Rowen M, Saatchi S, Schill S, Tabor K, Turner W, Vodacek A, Vogelmann J, Wegmann M, Wilkie D, Wilson C. Ten ways remote sensing can contribute to conservation. Conserv Biol 2015; 29:350-359. [PMID: 25319024 DOI: 10.1111/cobi.12397] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 07/04/2014] [Accepted: 07/14/2014] [Indexed: 06/04/2023]
Abstract
In an effort to increase conservation effectiveness through the use of Earth observation technologies, a group of remote sensing scientists affiliated with government and academic institutions and conservation organizations identified 10 questions in conservation for which the potential to be answered would be greatly increased by use of remotely sensed data and analyses of those data. Our goals were to increase conservation practitioners' use of remote sensing to support their work, increase collaboration between the conservation science and remote sensing communities, identify and develop new and innovative uses of remote sensing for advancing conservation science, provide guidance to space agencies on how future satellite missions can support conservation science, and generate support from the public and private sector in the use of remote sensing data to address the 10 conservation questions. We identified a broad initial list of questions on the basis of an email chain-referral survey. We then used a workshop-based iterative and collaborative approach to whittle the list down to these final questions (which represent 10 major themes in conservation): How can global Earth observation data be used to model species distributions and abundances? How can remote sensing improve the understanding of animal movements? How can remotely sensed ecosystem variables be used to understand, monitor, and predict ecosystem response and resilience to multiple stressors? How can remote sensing be used to monitor the effects of climate on ecosystems? How can near real-time ecosystem monitoring catalyze threat reduction, governance and regulation compliance, and resource management decisions? How can remote sensing inform configuration of protected area networks at spatial extents relevant to populations of target species and ecosystem services? How can remote sensing-derived products be used to value and monitor changes in ecosystem services? How can remote sensing be used to monitor and evaluate the effectiveness of conservation efforts? How does the expansion and intensification of agriculture and aquaculture alter ecosystems and the services they provide? How can remote sensing be used to determine the degree to which ecosystems are being disturbed or degraded and the effects of these changes on species and ecosystem functions?
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Affiliation(s)
- Robert A Rose
- Wildlife Conservation Society, Conservation Support, 2300 Southern Boulevard, Bronx, NY, 10460, U.S.A..
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50
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Egom EE, Vella K, Hua R, Jansen HJ, Moghtadaei M, Polina I, Bogachev O, Hurnik R, Mackasey M, Rafferty S, Ray G, Rose RA. Impaired sinoatrial node function and increased susceptibility to atrial fibrillation in mice lacking natriuretic peptide receptor C. J Physiol 2015; 593:1127-46. [PMID: 25641115 DOI: 10.1113/jphysiol.2014.283135] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Accepted: 12/06/2014] [Indexed: 12/17/2022] Open
Abstract
Natriuretic peptides (NPs) are critical regulators of the cardiovascular system that are currently viewed as possible therapeutic targets for the treatment of heart disease. Recent work demonstrates potent NP effects on cardiac electrophysiology, including in the sinoatrial node (SAN) and atria. NPs elicit their effects via three NP receptors (NPR-A, NPR-B and NPR-C). Among these receptors, NPR-C is poorly understood. Accordingly, the goal of this study was to determine the effects of NPR-C ablation on cardiac structure and arrhythmogenesis. Cardiac structure and function were assessed in wild-type (NPR-C(+/+)) and NPR-C knockout (NPR-C(-/-)) mice using echocardiography, intracardiac programmed stimulation, patch clamping, high-resolution optical mapping, quantitative polymerase chain reaction and histology. These studies demonstrate that NPR-C(-/-) mice display SAN dysfunction, as indicated by a prolongation (30%) of corrected SAN recovery time, as well as an increased susceptibility to atrial fibrillation (6% in NPR-C(+/+) vs. 47% in NPR-C(-/-)). There were no differences in SAN or atrial action potential morphology in NPR-C(-/-) mice; however, increased atrial arrhythmogenesis in NPR-C(-/-) mice was associated with reductions in SAN (20%) and atrial (15%) conduction velocity, as well as increases in expression and deposition of collagen in the atrial myocardium. No differences were seen in ventricular arrhythmogenesis or fibrosis in NPR-C(-/-) mice. This study demonstrates that loss of NPR-C results in SAN dysfunction and increased susceptibility to atrial arrhythmias in association with structural remodelling and fibrosis in the atrial myocardium. These findings indicate a critical protective role for NPR-C in the heart.
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Affiliation(s)
- Emmanuel E Egom
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
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