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Hadaya J, Dajani AH, Cha S, Hanna P, Challita R, Hoover DB, Ajijola OA, Shivkumar K, Ardell JL. Vagal Nerve Stimulation Reduces Ventricular Arrhythmias and Mitigates Adverse Neural Cardiac Remodeling Post-Myocardial Infarction. JACC Basic Transl Sci 2023; 8:1100-1118. [PMID: 37791302 PMCID: PMC10543930 DOI: 10.1016/j.jacbts.2023.03.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 03/29/2023] [Accepted: 03/29/2023] [Indexed: 10/05/2023]
Abstract
This study sought to evaluate the impact of chronic vagal nerve stimulation (cVNS) on cardiac and extracardiac neural structure/function after myocardial infarction (MI). Groups were control, MI, and MI + cVNS; cVNS was started 2 days post-MI. Terminal experiments were performed 6 weeks post-MI. MI impaired left ventricular mechanical function, evoked anisotropic electrical conduction, increased susceptibility to ventricular tachycardia and fibrillation, and altered neuronal and glial phenotypes in the stellate and dorsal root ganglia, including glial activation. cVNS improved cardiac mechanical function and reduced ventricular tachycardia/ventricular fibrillation post-MI, partly by stabilizing activation/repolarization in the border zone. MI-associated extracardiac neural remodeling, particularly glial activation, was mitigated with cVNS.
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Affiliation(s)
- Joseph Hadaya
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
- Molecular, Cellular, and Integrative Physiology Program, University of California, Los Angeles, Los Angeles, California, USA
| | - Al-Hassan Dajani
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Steven Cha
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Peter Hanna
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
- Molecular, Cellular, and Integrative Physiology Program, University of California, Los Angeles, Los Angeles, California, USA
| | - Ronald Challita
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Donald B. Hoover
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, USA
- Center of Excellence in Inflammation, Infectious Disease and Immunity, East Tennessee State University, Johnson City, Tennessee, USA
| | - Olujimi A. Ajijola
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
- Molecular, Cellular, and Integrative Physiology Program, University of California, Los Angeles, Los Angeles, California, USA
| | - Kalyanam Shivkumar
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
- Molecular, Cellular, and Integrative Physiology Program, University of California, Los Angeles, Los Angeles, California, USA
| | - Jeffrey L. Ardell
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
- Molecular, Cellular, and Integrative Physiology Program, University of California, Los Angeles, Los Angeles, California, USA
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Zhou L, Zhang Y, Cao G, Zhang C, Zheng C, Meng G, Lai Y, Zhou Z, Liu Z, Liu Z, Guo F, Dong X, Liang Z, Wang Y, Guo S, Zhou X, Jiang H, Yu L. Wireless Self-Powered Optogenetic System for Long-Term Cardiac Neuromodulation to Improve Post-MI Cardiac Remodeling and Malignant Arrhythmia. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2205551. [PMID: 36698262 PMCID: PMC10037959 DOI: 10.1002/advs.202205551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Revised: 12/02/2022] [Indexed: 06/17/2023]
Abstract
Autonomic imbalance is an important characteristic of patients after myocardial infarction (MI) and adversely contributes to post-MI cardiac remodeling and ventricular arrhythmias (VAs). A previous study proved that optogenetic modulation could precisely inhibit cardiac sympathetic hyperactivity and prevent acute ischemia-induced VAs. Here, a wireless self-powered optogenetic modulation system is introduced, which achieves long-term precise cardiac neuromodulation in ambulatory canines. The wireless self-powered optical system based on a triboelectric nanogenerator is powered by energy harvested from body motion and realized the effective optical illumination that is required for optogenetic neuromodulation (ON). It is further demonstrated that long-term ON significantly mitigates MI-induced sympathetic remodeling and hyperactivity, and improves a variety of clinically relevant outcomes such as improves ventricular dysfunction, reduces infarct size, increases electrophysiological stability, and reduces susceptibility to VAs. These novel insights suggest that wireless ON holds translational potential for the clinical treatment of arrhythmia and other cardiovascular diseases related to sympathetic hyperactivity. Moreover, this innovative self-powered optical system may provide an opportunity to develop implantable/wearable and self-controllable devices for long-term optogenetic therapy.
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Affiliation(s)
- Liping Zhou
- Department of CardiologyRenmin Hospital of Wuhan UniversityHubei Key Laboratory of Autonomic Nervous System ModulationCardiac Autonomic Nervous System Research Center of Wuhan UniversityTaikang Center for Life and Medical SciencesWuhan UniversityCardiovascular Research InstituteWuhan UniversityHubei Key Laboratory of CardiologyWuhan430060P. R. China
| | - Yuanzheng Zhang
- Department of CardiologyRenmin Hospital of Wuhan UniversityHubei Key Laboratory of Autonomic Nervous System ModulationCardiac Autonomic Nervous System Research Center of Wuhan UniversityTaikang Center for Life and Medical SciencesWuhan UniversityCardiovascular Research InstituteWuhan UniversityHubei Key Laboratory of CardiologyWuhan430060P. R. China
- Hubei Yangtze Memory LaboratoriesKey Laboratory of Artificial Micro, and Nano‐structures of Ministry of EducationSchool of Physics and TechnologyWuhan UniversityWuhan430072P. R. China
| | - Gang Cao
- Biomedical CenterCollege of Veterinary MedicineHuazhong Agricultural UniversityWuhan430072P. R. China
| | - Chi Zhang
- Wuhan National Laboratory for OptoelectronicsHuazhong University of Science and TechnologyWuhan430072P. R. China
| | - Chen Zheng
- Wuhan National Laboratory for OptoelectronicsHuazhong University of Science and TechnologyWuhan430072P. R. China
| | - Guannan Meng
- Department of CardiologyRenmin Hospital of Wuhan UniversityHubei Key Laboratory of Autonomic Nervous System ModulationCardiac Autonomic Nervous System Research Center of Wuhan UniversityTaikang Center for Life and Medical SciencesWuhan UniversityCardiovascular Research InstituteWuhan UniversityHubei Key Laboratory of CardiologyWuhan430060P. R. China
| | - Yanqiu Lai
- Department of CardiologyRenmin Hospital of Wuhan UniversityHubei Key Laboratory of Autonomic Nervous System ModulationCardiac Autonomic Nervous System Research Center of Wuhan UniversityTaikang Center for Life and Medical SciencesWuhan UniversityCardiovascular Research InstituteWuhan UniversityHubei Key Laboratory of CardiologyWuhan430060P. R. China
| | - Zhen Zhou
- Department of CardiologyRenmin Hospital of Wuhan UniversityHubei Key Laboratory of Autonomic Nervous System ModulationCardiac Autonomic Nervous System Research Center of Wuhan UniversityTaikang Center for Life and Medical SciencesWuhan UniversityCardiovascular Research InstituteWuhan UniversityHubei Key Laboratory of CardiologyWuhan430060P. R. China
| | - Zhihao Liu
- Department of CardiologyRenmin Hospital of Wuhan UniversityHubei Key Laboratory of Autonomic Nervous System ModulationCardiac Autonomic Nervous System Research Center of Wuhan UniversityTaikang Center for Life and Medical SciencesWuhan UniversityCardiovascular Research InstituteWuhan UniversityHubei Key Laboratory of CardiologyWuhan430060P. R. China
| | - Zihan Liu
- Department of CardiologyRenmin Hospital of Wuhan UniversityHubei Key Laboratory of Autonomic Nervous System ModulationCardiac Autonomic Nervous System Research Center of Wuhan UniversityTaikang Center for Life and Medical SciencesWuhan UniversityCardiovascular Research InstituteWuhan UniversityHubei Key Laboratory of CardiologyWuhan430060P. R. China
| | - Fuding Guo
- Department of CardiologyRenmin Hospital of Wuhan UniversityHubei Key Laboratory of Autonomic Nervous System ModulationCardiac Autonomic Nervous System Research Center of Wuhan UniversityTaikang Center for Life and Medical SciencesWuhan UniversityCardiovascular Research InstituteWuhan UniversityHubei Key Laboratory of CardiologyWuhan430060P. R. China
| | - Xin Dong
- Wuhan National Laboratory for OptoelectronicsHuazhong University of Science and TechnologyWuhan430072P. R. China
| | - Zhizhuo Liang
- Wuhan National Laboratory for OptoelectronicsHuazhong University of Science and TechnologyWuhan430072P. R. China
| | - Yueyi Wang
- Department of CardiologyRenmin Hospital of Wuhan UniversityHubei Key Laboratory of Autonomic Nervous System ModulationCardiac Autonomic Nervous System Research Center of Wuhan UniversityTaikang Center for Life and Medical SciencesWuhan UniversityCardiovascular Research InstituteWuhan UniversityHubei Key Laboratory of CardiologyWuhan430060P. R. China
| | - Shishang Guo
- Hubei Yangtze Memory LaboratoriesKey Laboratory of Artificial Micro, and Nano‐structures of Ministry of EducationSchool of Physics and TechnologyWuhan UniversityWuhan430072P. R. China
| | - Xiaoya Zhou
- Department of CardiologyRenmin Hospital of Wuhan UniversityHubei Key Laboratory of Autonomic Nervous System ModulationCardiac Autonomic Nervous System Research Center of Wuhan UniversityTaikang Center for Life and Medical SciencesWuhan UniversityCardiovascular Research InstituteWuhan UniversityHubei Key Laboratory of CardiologyWuhan430060P. R. China
| | - Hong Jiang
- Department of CardiologyRenmin Hospital of Wuhan UniversityHubei Key Laboratory of Autonomic Nervous System ModulationCardiac Autonomic Nervous System Research Center of Wuhan UniversityTaikang Center for Life and Medical SciencesWuhan UniversityCardiovascular Research InstituteWuhan UniversityHubei Key Laboratory of CardiologyWuhan430060P. R. China
| | - Lilei Yu
- Department of CardiologyRenmin Hospital of Wuhan UniversityHubei Key Laboratory of Autonomic Nervous System ModulationCardiac Autonomic Nervous System Research Center of Wuhan UniversityTaikang Center for Life and Medical SciencesWuhan UniversityCardiovascular Research InstituteWuhan UniversityHubei Key Laboratory of CardiologyWuhan430060P. R. China
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Spinal Cord Stimulation Attenuates Neural Remodeling, Inflammation, and Fibrosis After Myocardial Infarction. Neuromodulation 2023; 26:57-67. [PMID: 35088742 DOI: 10.1016/j.neurom.2021.09.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 10/22/2020] [Accepted: 09/28/2021] [Indexed: 01/11/2023]
Abstract
OBJECTIVES Spinal cord stimulation (SCS) is an established neuromodulation method that regulates the cardiac autonomic system. However, the biological mechanisms of the therapeutic effects of SCS after myocardial infarction (MI) remain unclear. MATERIALS AND METHODS Twenty-five rabbits were divided into five groups: SCS-MI (voltage: 0.5 v; pulse width: 0.2 ms; 50 Hz; ten minutes on and 30 minutes off; two weeks; n = 5), MI (n = 5), sham SCS-MI (voltage: 0 v; two weeks; n = 5), sham MI (n = 5), and blank control (n = 5) groups. MI was induced by permanent left anterior descending artery ligation. SCS-MI and sham SCS-MI rabbits received the corresponding interventions 24 hours after MI. Autonomic remodeling was evaluated using enzyme-linked immunosorbent assay and immunohistochemistry. Inflammation and myocardial fibrosis were assessed using immunohistochemistry, quantitative polymerase chain reaction, hematoxylin and eosin staining, Masson staining, and Western blot. RESULTS SCS improved the abnormal systemic autonomic activity. Cardiac norepinephrine decreased after MI (p < 0.01) and did not improve with SCS. Cardiac acetylcholine increased with SCS compared with the MI group (p < 0.05). However, no difference was observed between the MI and blank control groups. Growth-associated protein 43 (p < 0.001) and tyrosine hydroxylase (p < 0.001) increased whereas choline acetyltransferase (p < 0.05) decreased in the MI group compared with the blank control group. These changes were attenuated with SCS. SCS inhibited inflammation, decreased the ratio of phosphorylated-Erk to Erk (p < 0.001), and increased the ratio of phosphorylated-STAT3 to STAT3 (p < 0.001) compared with the MI group. Myocardial fibrosis was also attenuated by SCS. CONCLUSIONS SCS improved abnormal autonomic activity after MI, leading to reduced inflammation, reactivation of STAT3, and inhibition of Erk. Additionally, SCS attenuated myocardial fibrosis. Our results warrant future studies of biological mechanisms of the therapeutic effects of SCS after MI.
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Structural and function organization of intrathoracic extracardiac autonomic projections to the porcine heart: implications for targeted neuromodulation therapy. Heart Rhythm 2022; 19:975-983. [DOI: 10.1016/j.hrthm.2022.01.033] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 01/20/2022] [Accepted: 01/28/2022] [Indexed: 12/30/2022]
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Orozco SC, Arias MP, Carvajal PA, Gallo‐Villegas J, Olivera‐Angel M. Efficacy of high-intensity interval training compared with moderate-intensity continuous training on maximal aerobic potency in dogs: Trial protocol for a randomised controlled clinical study. Vet Rec Open 2021; 8:e4. [PMID: 33981438 PMCID: PMC8109980 DOI: 10.1002/vro2.4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 01/14/2021] [Accepted: 01/18/2021] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND High-intensity interval training (HIIT) is a more efficient method to improve exercise capacity than moderate-intensity continuous training (MICT) because of its greater physiological stimulus. OBJECTIVE The aim of this protocol is to evaluate the efficacy of HIIT on maximal aerobic potency in dogs as compared to MICT. METHODS This protocol is for a randomised, blinded controlled clinical trial, with three parallel groups for the purpose of demonstrating superiority. Thirty dogs aged between 12 and 84 months of both sexes and different breeds will be included. Dogs, before initiating and after finalising the training will perform an incremental exercise test on a treadmill to obtain maximal speed and lactate threshold; resting parameters of heart and respiratory rate, left ventricle chamber and systolic function will be measured. Dogs assigned to each intervention will endure a 42-min session of HIIT or MICT during 12 weeks. HIIT comprises four intervals of 4 min each at a load of 85%, alternating with a 4-min resting period. MICT group will have a continuous load of 60%. The control group will remain in a cage. An intention-to-treat statistical analysis will be implemented. Analysis of covariance will be used to estimate the effect of HIIT compared with MICT training on maximal aerobic potency, aerobic resistance, systolic function at rest, left ventricle chamber measurements and indexes, respiratory rate and HR at rest. CONCLUSION Significant time and effort are invested into training sports/working dogs, which could benefit from improving physical capacity by means of the HIIT methodology.
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Affiliation(s)
- Sonia C. Orozco
- Biogenesis Research GroupFacultad de Ciencias AgrariasUniversidad de AntioquiaMedellínAntioquiaColombia
| | | | - Pablo A. Carvajal
- Servicio de CardiologíaHospital VeterinarioFacultad de Ciencias AgrariasUniversidad de AntioquiaMedellínAntioquiaColombia
| | | | - Martha Olivera‐Angel
- Biogenesis Research GroupFacultad de Ciencias AgrariasUniversidad de AntioquiaMedellínAntioquiaColombia
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van Weperen VYH, Vos MA, Ajijola OA. Autonomic modulation of ventricular electrical activity: recent developments and clinical implications. Clin Auton Res 2021; 31:659-676. [PMID: 34591191 PMCID: PMC8629778 DOI: 10.1007/s10286-021-00823-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 08/12/2021] [Indexed: 12/19/2022]
Abstract
PURPOSE This review aimed to provide a complete overview of the current stance and recent developments in antiarrhythmic neuromodulatory interventions, focusing on lifethreatening vetricular arrhythmias. METHODS Both preclinical studies and clinical studies were assessed to highlight the gaps in knowledge that remain to be answered and the necessary steps required to properly translate these strategies to the clinical setting. RESULTS Cardiac autonomic imbalance, characterized by chronic sympathoexcitation and parasympathetic withdrawal, destabilizes cardiac electrophysiology and promotes ventricular arrhythmogenesis. Therefore, neuromodulatory interventions that target the sympatho-vagal imbalance have emerged as promising antiarrhythmic strategies. These strategies are aimed at different parts of the cardiac neuraxis and directly or indirectly restore cardiac autonomic tone. These interventions include pharmacological blockade of sympathetic neurotransmitters and neuropeptides, cardiac sympathetic denervation, thoracic epidural anesthesia, and spinal cord and vagal nerve stimulation. CONCLUSION Neuromodulatory strategies have repeatedly been demonstrated to be highly effective and very promising anti-arrhythmic therapies. Nevertheless, there is still much room to gain in our understanding of neurocardiac physiology, refining the current neuromodulatory strategic options and elucidating the chronic effects of many of these strategic options.
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Affiliation(s)
- Valerie Y H van Weperen
- Department of Medical Physiology, Universitair Medisch Centrum Utrecht, Utrecht, The Netherlands
- UCLA Cardiac Arrhythmia Center, UCLA Neurocardiology Research Center, UCLA Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, University of California, 100 Medical Plaza, Suite 660, Westwood Blvd, Los Angeles, CA, 90095-1679, USA
| | - Marc A Vos
- Department of Medical Physiology, Universitair Medisch Centrum Utrecht, Utrecht, The Netherlands
| | - Olujimi A Ajijola
- UCLA Cardiac Arrhythmia Center, UCLA Neurocardiology Research Center, UCLA Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, University of California, 100 Medical Plaza, Suite 660, Westwood Blvd, Los Angeles, CA, 90095-1679, USA.
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Kulkarni K, Stavrakis S, Elkholey K, Singh JP, Parks KA, Armoundas AA. Microvolt T-Wave Alternans Is Modulated by Acute Low-Level Tragus Stimulation in Patients With Ischemic Cardiomyopathy and Heart Failure. Front Physiol 2021; 12:707724. [PMID: 34366894 PMCID: PMC8343129 DOI: 10.3389/fphys.2021.707724] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 06/30/2021] [Indexed: 12/15/2022] Open
Abstract
Aims: Microvolt T-wave alternans (TWA), an oscillation in T-wave morphology of the electrocardiogram (ECG), has been associated with increased susceptibility to ventricular tachy-arrhythmias, while vagus nerve stimulation has shown promising anti-arrhythmic effects in in vivo and ex vivo animal studies. We aimed to examine the effect of non-invasive, acute low-level tragus stimulation (LLTS) on TWA in patients with ischemic cardiomyopathy and heart failure. Methods: 26 patients with ischemic cardiomyopathy (left ventricular ejection fraction <35%) and chronic stable heart failure, previously implanted with an automatic implantable cardioverter defibrillator (ICD) device with an atrial lead (dual chamber ICD or cardiac resynchronization therapy defibrillator), were enrolled in the study. Each patient sequentially received, (1) Sham LLTS (electrode on tragus, but no stimulation delivered) for 5 min; (2) Active LLTS at two different frequencies (5 and 20 Hz, 15 min each); and (3) Active LLTS, during concomitant atrial pacing at 100 bpm at two different frequencies (5 and 20 Hz, 15 min each). LLTS was delivered through a transcutaneous electrical nerve stimulation device (pulse width 200 μs, frequency 5/20 Hz, amplitude 1 mA lower than the discomfort threshold). TWA burden was assessed using continuous ECG monitoring during sham and active LLTS in sinus rhythm, as well as during atrial pacing. Results: Right atrial pacing at 100 bpm led to significantly heightened TWA burden compared to sinus rhythm, with or without LLTS. Acute LLTS at both 5 and 20 Hz, during sinus rhythm led to a significant rise in TWA burden in the precordial leads (p < 0.05). Conclusion: Acute LLTS results in a heart-rate dependent increase in TWA burden.
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Affiliation(s)
- Kanchan Kulkarni
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA, United States
| | - Stavros Stavrakis
- Heart Rhythm Institute, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Khaled Elkholey
- Heart Rhythm Institute, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Jagmeet P Singh
- Cardiology Division, Cardiac Arrhythmia Service, Massachusetts General Hospital, Boston, MA, United States
| | - Kimberly A Parks
- Cardiology Division, Brigham and Women's Hospital, Boston, MA, United States
| | - Antonis A Armoundas
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA, United States.,Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, United States
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Fazlollahi F, Santini Gonzalez JJ, Repas SJ, Canan BD, Billman GE, Janssen PML. Contraction-relaxation coupling is unaltered by exercise training and infarction in isolated canine myocardium. J Gen Physiol 2021; 153:211978. [PMID: 33847735 PMCID: PMC8047736 DOI: 10.1085/jgp.202012829] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 02/20/2021] [Accepted: 03/18/2021] [Indexed: 12/28/2022] Open
Abstract
The two main phases of the mammalian cardiac cycle are contraction and relaxation; however, whether there is a connection between them in humans is not well understood. Routine exercise has been shown to improve cardiac function, morphology, and molecular signatures. Likewise, the acute and chronic changes that occur in the heart in response to injury, disease, and stress are well characterized, albeit not fully understood. In this study, we investigated how exercise and myocardial injury affect contraction–relaxation coupling. We retrospectively analyzed the correlation between the maximal speed of contraction and the maximal speed of relaxation of canine myocardium after receiving surgically induced myocardial infarction, followed by either sedentary recovery or exercise training for 10–12 wk. We used isolated right ventricular trabeculae, which were electrically paced at different lengths, frequencies, and with increasing β-adrenoceptor stimulation. In all conditions, contraction and relaxation were linearly correlated, irrespective of injury or training history. Based on these results and the available literature, we posit that contraction–relaxation coupling is a fundamental myocardial property that resides in the structural arrangement of proteins at the level of the sarcomere and that this may be regulated by the actions of cardiac myosin binding protein C (cMyBP-C) on actin and myosin.
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Affiliation(s)
- Farbod Fazlollahi
- Department of Physiology and Cell Biology, College of Medicine, Ohio State University, Columbus, OH
| | - Jorge J Santini Gonzalez
- Department of Physiology and Cell Biology, College of Medicine, Ohio State University, Columbus, OH
| | - Steven J Repas
- Department of Physiology and Cell Biology, College of Medicine, Ohio State University, Columbus, OH
| | - Benjamin D Canan
- Department of Physiology and Cell Biology, College of Medicine, Ohio State University, Columbus, OH
| | - George E Billman
- Department of Physiology and Cell Biology, College of Medicine, Ohio State University, Columbus, OH
| | - Paul M L Janssen
- Department of Physiology and Cell Biology, College of Medicine, Ohio State University, Columbus, OH
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Hadaya J, Ardell JL. Autonomic Modulation for Cardiovascular Disease. Front Physiol 2020; 11:617459. [PMID: 33414727 PMCID: PMC7783451 DOI: 10.3389/fphys.2020.617459] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 11/25/2020] [Indexed: 12/11/2022] Open
Abstract
Dysfunction of the autonomic nervous system has been implicated in the pathogenesis of cardiovascular disease, including congestive heart failure and cardiac arrhythmias. Despite advances in the medical and surgical management of these entities, progression of disease persists as does the risk for sudden cardiac death. With improved knowledge of the dynamic relationships between the nervous system and heart, neuromodulatory techniques such as cardiac sympathetic denervation and vagal nerve stimulation (VNS) have emerged as possible therapeutic approaches for the management of these disorders. In this review, we present the structure and function of the cardiac nervous system and the remodeling that occurs in disease states, emphasizing the concept of increased sympathoexcitation and reduced parasympathetic tone. We review preclinical evidence for vagal nerve stimulation, and early results of clinical trials in the setting of congestive heart failure. Vagal nerve stimulation, and other neuromodulatory techniques, may improve the management of cardiovascular disorders, and warrant further study.
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Affiliation(s)
- Joseph Hadaya
- University of California, Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, CA, United States.,UCLA Neurocardiology Research Program of Excellence, UCLA, Los Angeles, CA, United States.,Molecular, Cellular, and Integrative Physiology Program, UCLA, Los Angeles, CA, United States
| | - Jeffrey L Ardell
- University of California, Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, CA, United States.,UCLA Neurocardiology Research Program of Excellence, UCLA, Los Angeles, CA, United States
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Lozano WM, Parra G, Arias-Mutis OJ, Zarzoso M. Exercise Training Protocols in Rabbits Applied in Cardiovascular Research. Animals (Basel) 2020; 10:ani10081263. [PMID: 32722314 PMCID: PMC7459864 DOI: 10.3390/ani10081263] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 07/22/2020] [Accepted: 07/22/2020] [Indexed: 11/20/2022] Open
Abstract
Simple Summary Several animal models have been used to understand the physiological adaptations produced by exercise training in the healthy and diseased cardiovascular system. Among those, the protocols for acute and chronic exercise in rabbits present several advantages compared to other large animal models. In addition, the rabbit model has important physiological similarities with humans. On the other hand, the design of the training protocol is a key factor to induce the physiological adaptations. Here, we review the different training protocols used in rabbits and the different physiological adaptations produced in the cardiovascular system, in normal and pathological conditions. Abstract Rabbit exercise protocols allow for the evaluation of physiological and biomechanical changes and responses to episodes of acute or chronic exercise. The observed physiological changes are normal responses to stress, that is, adaptive responses to maintain or restore homeostasis after acute exercise. Indeed, the rabbit model is advantageous since (a) it has important physiological similarities in terms of the functioning of multiple organ systems, and can quickly induce alterations in pathophysiological conditions that resemble those of humans, and (b) it allows the implementation of a low-cost model in comparison with other large animals. When designing an exercise training protocol for rabbits, it is important to consider variables such as race, gender, age and, especially, training parameters such as volume, intensity, or rest, among others, to determine the outcome of the research. Therefore, the objective of this review is to identify and analyze exercise training protocols in rabbits in different experimental applications and the various physiological adaptations that are presented, with special focus in cardiovascular adaptations.
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Affiliation(s)
- Wilson M. Lozano
- Department of Physiology, Universitat de València, 46010 Valencia, Spain; (W.M.L.); (G.P.); (O.J.A.-M.)
| | - Germán Parra
- Department of Physiology, Universitat de València, 46010 Valencia, Spain; (W.M.L.); (G.P.); (O.J.A.-M.)
- INCLIVA, Instituto de Investigación Sanitaria, 46010 Valencia, Spain
| | - Oscar J. Arias-Mutis
- Department of Physiology, Universitat de València, 46010 Valencia, Spain; (W.M.L.); (G.P.); (O.J.A.-M.)
- INCLIVA, Instituto de Investigación Sanitaria, 46010 Valencia, Spain
- CIBERCV, Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Manuel Zarzoso
- Department of Physiotherapy, Universitat de València, 46010 Valencia, Spain
- Correspondence: ; Tel.: +34-963-983-853
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Ardell JL, Foreman RD, Armour JA, Shivkumar K. Cardiac sympathectomy and spinal cord stimulation attenuate reflex-mediated norepinephrine release during ischemia preventing ventricular fibrillation. JCI Insight 2019; 4:131648. [PMID: 31671074 DOI: 10.1172/jci.insight.131648] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 10/23/2019] [Indexed: 12/15/2022] Open
Abstract
The purpose of this study was to define the mechanism by which cardiac neuraxial decentralization or spinal cord stimulation (SCS) reduces ischemia-induced ventricular fibrillation (VF). Direct measurements of norepinephrine (NE) levels in the left ventricular interstitial fluid (ISF) by microdialysis, in response to transient (15-minute) coronary artery occlusion (CAO), were performed in anesthetized canines. Responses were studied in animals with intact neuraxes and were compared with those in which the intrathoracic component of the cardiac neuraxes (stellate ganglia) or the intrinsic cardiac neuronal (ICN) system was surgically delinked from the central nervous system and those with intact neuraxes with preemptive SCS (T1-T3). With intact neuraxes, animals with exaggerated NE release due to CAO were at increased risk for VF. During CAO, there was a 152% increase in NE when the neuraxes were intact compared with 114% following stellate decentralization and 16% following ICN decentralization. During SCS, CAO NE levels increased by 59%. Risk for CAO-induced VF was 38% in controls, 8% following decentralization, and 11% following SCS. These data indicate that ischemia-related afferent neuronal transmission differentially engages central and intrathoracic sympathetic reflexes and amplifies sympathoexcitation. Differences in regional ventricular NE release are associated with increased risk for VF. Surgical decentralization or SCS reduced NE release and VF.
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Affiliation(s)
- Jeffrey L Ardell
- UCLA Cardiac Arrhythmia Center, UCLA Health System, Los Angeles, California, USA.,Neurocardiology Research Program of Excellence and.,Molecular Cellular and Integrative Physiology, UCLA, Los Angeles, California, USA.,Department of Biomedical Sciences, East Tennessee State University, Johnson City, Tennessee, USA
| | - Robert D Foreman
- Department of Physiology, University of Oklahoma Health Science Center, Oklahoma City, Oklahoma, USA
| | - J Andrew Armour
- UCLA Cardiac Arrhythmia Center, UCLA Health System, Los Angeles, California, USA.,Neurocardiology Research Program of Excellence and
| | - Kalyanam Shivkumar
- UCLA Cardiac Arrhythmia Center, UCLA Health System, Los Angeles, California, USA.,Neurocardiology Research Program of Excellence and.,Molecular Cellular and Integrative Physiology, UCLA, Los Angeles, California, USA.,Neuroscience Interdepartmental Programs, UCLA, Los Angeles, California, USA
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12
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Kulkarni K, Merchant FM, Kassab MB, Sana F, Moazzami K, Sayadi O, Singh JP, Heist EK, Armoundas AA. Cardiac Alternans: Mechanisms and Clinical Utility in Arrhythmia Prevention. J Am Heart Assoc 2019; 8:e013750. [PMID: 31617437 PMCID: PMC6898836 DOI: 10.1161/jaha.119.013750] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Kanchan Kulkarni
- Cardiovascular Research CenterMassachusetts General HospitalBostonMA
| | | | - Mohamad B. Kassab
- Cardiovascular Research CenterMassachusetts General HospitalBostonMA
| | - Furrukh Sana
- Cardiovascular Research CenterMassachusetts General HospitalBostonMA
| | - Kasra Moazzami
- Cardiovascular Research CenterMassachusetts General HospitalBostonMA
| | - Omid Sayadi
- Cardiovascular Research CenterMassachusetts General HospitalBostonMA
| | - Jagmeet P. Singh
- Cardiology DivisionCardiac Arrhythmia ServiceMassachusetts General HospitalBostonMA
| | - E. Kevin Heist
- Cardiology DivisionCardiac Arrhythmia ServiceMassachusetts General HospitalBostonMA
| | - Antonis A. Armoundas
- Cardiovascular Research CenterMassachusetts General HospitalBostonMA
- Institute for Medical Engineering and ScienceMassachusetts Institute of TechnologyCambridgeMA
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13
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Gevaert AB, Adams V, Bahls M, Bowen TS, Cornelissen V, Dörr M, Hansen D, Kemps HM, Leeson P, Van Craenenbroeck EM, Kränkel N. Towards a personalised approach in exercise-based cardiovascular rehabilitation: How can translational research help? A 'call to action' from the Section on Secondary Prevention and Cardiac Rehabilitation of the European Association of Preventive Cardiology. Eur J Prev Cardiol 2019; 27:1369-1385. [PMID: 31581819 DOI: 10.1177/2047487319877716] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The benefit of regular physical activity and exercise training for the prevention of cardiovascular and metabolic diseases is undisputed. Many molecular mechanisms mediating exercise effects have been deciphered. Personalised exercise prescription can help patients in achieving their individual greatest benefit from an exercise-based cardiovascular rehabilitation programme. Yet, we still struggle to provide truly personalised exercise prescriptions to our patients. In this position paper, we address novel basic and translational research concepts that can help us understand the principles underlying the inter-individual differences in the response to exercise, and identify early on who would most likely benefit from which exercise intervention. This includes hereditary, non-hereditary and sex-specific concepts. Recent insights have helped us to take on a more holistic view, integrating exercise-mediated molecular mechanisms with those influenced by metabolism and immunity. Unfortunately, while the outline is recognisable, many details are still lacking to turn the understanding of a concept into a roadmap ready to be used in clinical routine. This position paper therefore also investigates perspectives on how the advent of 'big data' and the use of animal models could help unravel inter-individual responses to exercise parameters and thus influence hypothesis-building for translational research in exercise-based cardiovascular rehabilitation.
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Affiliation(s)
- Andreas B Gevaert
- GENCOR Department, University of Antwerp, Belgium.,Department of Cardiology, Antwerp University Hospital (UZA), Belgium.,Heart Centre Hasselt, Jessa Hospital, Belgium
| | - Volker Adams
- Department of Molecular and Experimental Cardiology, TU Dresden, Germany
| | - Martin Bahls
- Department of Internal Medicine B, University of Greifswald, Germany.,German Centre for Cardiovascular Research (DZHK), partner site Greifswald, Germany
| | - T Scott Bowen
- School of Biomedical Sciences, University of Leeds, UK
| | | | - Marcus Dörr
- Department of Internal Medicine B, University of Greifswald, Germany.,German Centre for Cardiovascular Research (DZHK), partner site Greifswald, Germany
| | - Dominique Hansen
- Heart Centre Hasselt, Jessa Hospital, Belgium.,Faculty of Rehabilitation Sciences, Hasselt University, Belgium
| | - Hareld Mc Kemps
- Fitheid, Leefstijl, Ontwikkeling en Wetenschap (FLOW), Máxima Medical Centre, The Netherlands
| | - Paul Leeson
- Oxford Cardiovascular Clinical Research Facility, University of Oxford, UK
| | - Emeline M Van Craenenbroeck
- GENCOR Department, University of Antwerp, Belgium.,Department of Cardiology, Antwerp University Hospital (UZA), Belgium
| | - Nicolle Kränkel
- Department of Cardiology, Charité Universitätsmedizin, Germany.,German Centre for Cardiovascular Research (DZHK), partner site Berlin, Germany
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14
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Piktel JS, Wilson LD. Translational Models of Arrhythmia Mechanisms and Susceptibility: Success and Challenges of Modeling Human Disease. Front Cardiovasc Med 2019; 6:135. [PMID: 31552276 PMCID: PMC6748164 DOI: 10.3389/fcvm.2019.00135] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 08/27/2019] [Indexed: 01/10/2023] Open
Abstract
We discuss large animal translational models of arrhythmia susceptibility and sudden cardiac death, focusing on important considerations when interpreting the data derived before applying them to human trials. The utility of large animal models of arrhythmia and the pros and cons of specific translational large animals used will be discussed, including the necessary tradeoffs between models designed to derive mechanisms vs. those to test therapies. Recent technical advancements which can be applied to large animal models of arrhythmias to better elucidate mechanistic insights will be introduced. Finally, some specific examples of past successes and challenges in translating the results of large animal models of arrhythmias to clinical trials and practice will be examined, and common themes regarding the success and failure of translating studies to therapy in man will be discussed.
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Affiliation(s)
- Joseph S Piktel
- Department of Emergency Medicine, Emergency Care Research Institute and Heart and Vascular Research Center, MetroHealth Campus of Case Western Reserve University, Cleveland, OH, United States
| | - Lance D Wilson
- Department of Emergency Medicine, Emergency Care Research Institute and Heart and Vascular Research Center, MetroHealth Campus of Case Western Reserve University, Cleveland, OH, United States
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15
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Sleep disorders, nocturnal blood pressure, and cardiovascular risk: A translational perspective. Auton Neurosci 2019; 218:31-42. [DOI: 10.1016/j.autneu.2019.02.006] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Revised: 02/16/2019] [Accepted: 02/21/2019] [Indexed: 12/12/2022]
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16
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Such-Miquel L, Brines L, Alberola AM, Zarzoso M, Chorro FJ, Guerrero J, Parra G, Gallego N, Soler C, Del Canto I, Guill A, Such L. Effect of chronic exercise on myocardial electrophysiological heterogeneity and stability. Role of intrinsic cholinergic neurons: A study in the isolated rabbit heart. PLoS One 2018; 13:e0209085. [PMID: 30562383 PMCID: PMC6298659 DOI: 10.1371/journal.pone.0209085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 11/19/2018] [Indexed: 11/19/2022] Open
Abstract
A study has been made of the effect of chronic exercise on myocardial electrophysiological heterogeneity and stability, as well as of the role of cholinergic neurons in these changes. Determinations in hearts from untrained and trained rabbits on a treadmill were performed. The hearts were isolated and perfused. A pacing electrode and a recording multielectrode were located in the left ventricle. The parameters determined during induced VF, before and after atropine (1μM), were: fibrillatory cycle length (VV), ventricular functional refractory period (FRPVF), normalized energy (NE) of the fibrillatory signal and its coefficient of variation (CV), and electrical ventricular activation complexity, as an approach to myocardial heterogeneity and stability. The VV interval was longer in the trained group than in the control group both prior to atropine (78±10 vs. 68±10 ms) and after atropine (76±8 vs. 67±10 ms). Likewise, FRPVF was longer in the trained group than in the control group both prior to and after atropine (53±8 vs. 42±7 ms and 50±6 vs. 40±6 ms, respectively), and atropine did not modify FRPVF. The CV of FRPVF was lower in the trained group than in the control group prior to atropine (12.5±1.5% vs. 15.1±3.8%) and, decreased after atropine (15.1±3.8% vs. 12.2±2.4%) in the control group. The trained group showed higher NE values before (0.40±0.04 vs. 0.36±0.05) and after atropine (0.37±0.04 vs. 0.34±0.06; p = 0.08). Training decreased the CV of NE both before (23.3±2% vs. 25.2±4%; p = 0.08) and after parasympathetic blockade (22.6±1% vs. 26.1±5%). Cholinergic blockade did not modify these parameters within the control and trained groups. Activation complexity was lower in the trained than in the control animals before atropine (34±8 vs. 41±5), and increased after atropine in the control group (41±5 vs. 48±9, respectively). Thus, training decreases the intrinsic heterogeneity of the myocardium, increases electrophysiological stability, and prevents some modifications due to muscarinic block.
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Affiliation(s)
- Luis Such-Miquel
- Department of Physiotherapy, Universitat de València, Valencia, Spain
- Health Research Institute (INCLIVA), Valencia, Spain
| | - Laia Brines
- Health Research Institute (INCLIVA), Valencia, Spain
- Department of Physiology, Universitat de València, Valencia, Spain
| | - Antonio M. Alberola
- Health Research Institute (INCLIVA), Valencia, Spain
- Department of Physiology, Universitat de València, Valencia, Spain
| | - Manuel Zarzoso
- Department of Physiotherapy, Universitat de València, Valencia, Spain
- Health Research Institute (INCLIVA), Valencia, Spain
| | - Francisco J. Chorro
- Health Research Institute (INCLIVA), Valencia, Spain
- Department of Medicine, Universitat de València, Valencia, Spain
| | - Juan Guerrero
- Department of Electronic Engineering, Universitat de València, Valencia, Spain
| | - Germán Parra
- Health Research Institute (INCLIVA), Valencia, Spain
- Department of Physiology, Universitat de València, Valencia, Spain
| | | | - Carlos Soler
- Health Research Institute (INCLIVA), Valencia, Spain
- Department of Physiology, Universitat de València, Valencia, Spain
| | | | - Antonio Guill
- ITACA, Universitat Politècnica de València, Valencia, Spain
| | - Luis Such
- Health Research Institute (INCLIVA), Valencia, Spain
- Department of Physiology, Universitat de València, Valencia, Spain
- * E-mail:
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17
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Berntson GG. Presidential Address 2011: Autonomic modes of control and health. Psychophysiology 2018; 56:e13306. [DOI: 10.1111/psyp.13306] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 10/30/2018] [Accepted: 10/30/2018] [Indexed: 12/19/2022]
Affiliation(s)
- Gary G. Berntson
- Department of Psychology The Ohio State University Columbus Ohio
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18
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Nodera M, Oikawa M, Nakazato K, Ishida T, Takeishi Y. Sympathetic nervous remodeling is induced in the intermediolateral nucleus after myocardial infarction – Role of BDNF-TrkB axis-. Neurosci Lett 2018; 685:114-123. [DOI: 10.1016/j.neulet.2018.08.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 07/06/2018] [Accepted: 08/05/2018] [Indexed: 01/15/2023]
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20
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Colussi G, Catena C, Fagotto V, Darsiè D, Brosolo G, Bertin N, Sechi LA. Atrial fibrillation and its complications in arterial hypertension: The potential preventive role of ω-3 polyunsaturated fatty acids. Crit Rev Food Sci Nutr 2018; 59:1937-1948. [PMID: 29381383 DOI: 10.1080/10408398.2018.1434126] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Atrial fibrillation (AF) is the most common type of arrhythmia in the general population with a prevalence that reaches one third of patients with arterial hypertension. Several risk factors frequently associated with hypertension predispose the myocardium to AF by inducing atrial inflammation and fibrosis and altering atrial electrical and mechanical characteristics. AF influences the quality of life of hypertensive patients since it increases incidence of stroke and other thromboembolic events, and mortality. Polyunsaturated fatty acids of the ω-3 family (ω-3 PUFA) have been demonstrated to be beneficial in cardiovascular disease prevention by reducing plasma lipids and blood pressure levels and decreasing the risk of sudden death. These fatty acids can act as potent anti-inflammatory and anti-arrhythmic agents. Many studies have investigated a possible preventive effect of ω-3 PUFA on incident AF reporting contradictory results. This article overviews the evidence currently available on this important topic and provides some conclusive remarks on the possibility that these fatty acids could be beneficial in hypertensive patients.
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Affiliation(s)
- GianLuca Colussi
- a Division of Internal Medicine, Department of Medicine , University of Udine , Udine , Italy
| | - Cristiana Catena
- a Division of Internal Medicine, Department of Medicine , University of Udine , Udine , Italy
| | - Valentina Fagotto
- a Division of Internal Medicine, Department of Medicine , University of Udine , Udine , Italy
| | - Daniele Darsiè
- a Division of Internal Medicine, Department of Medicine , University of Udine , Udine , Italy
| | - Gabriele Brosolo
- a Division of Internal Medicine, Department of Medicine , University of Udine , Udine , Italy
| | - Nicole Bertin
- a Division of Internal Medicine, Department of Medicine , University of Udine , Udine , Italy
| | - Leonardo A Sechi
- a Division of Internal Medicine, Department of Medicine , University of Udine , Udine , Italy
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21
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Autonomic Control of the Heart. Neuromodulation 2018. [DOI: 10.1016/b978-0-12-805353-9.00104-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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22
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Neuromodulation Therapies for Cardiac Disease. Neuromodulation 2018. [DOI: 10.1016/b978-0-12-805353-9.00129-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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23
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Ardell JL, Nier H, Hammer M, Southerland EM, Ardell CL, Beaumont E, KenKnight BH, Armour JA. Defining the neural fulcrum for chronic vagus nerve stimulation: implications for integrated cardiac control. J Physiol 2017; 595:6887-6903. [PMID: 28862330 DOI: 10.1113/jp274678] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 08/14/2017] [Indexed: 12/12/2022] Open
Abstract
KEY POINTS The evoked cardiac response to bipolar cervical vagus nerve stimulation (VNS) reflects a dynamic interaction between afferent mediated decreases in central parasympathetic drive and suppressive effects evoked by direct stimulation of parasympathetic efferent axons to the heart. The neural fulcrum is defined as the operating point, based on frequency-amplitude-pulse width, where a null heart rate response is reproducibly evoked during the on-phase of VNS. Cardiac control, based on the principal of the neural fulcrum, can be elicited from either vagus. Beta-receptor blockade does not alter the tachycardia phase to low intensity VNS, but can increase the bradycardia to higher intensity VNS. While muscarinic cholinergic blockade prevented the VNS-induced bradycardia, clinically relevant doses of ACE inhibitors, beta-blockade and the funny channel blocker ivabradine did not alter the VNS chronotropic response. While there are qualitative differences in VNS heart control between awake and anaesthetized states, the physiological expression of the neural fulcrum is maintained. ABSTRACT Vagus nerve stimulation (VNS) is an emerging therapy for treatment of chronic heart failure and remains a standard of therapy in patients with treatment-resistant epilepsy. The objective of this work was to characterize heart rate (HR) responses (HRRs) during the active phase of chronic VNS over a wide range of stimulation parameters in order to define optimal protocols for bidirectional bioelectronic control of the heart. In normal canines, bipolar electrodes were chronically implanted on the cervical vagosympathetic trunk bilaterally with anode cephalad to cathode (n = 8, 'cardiac' configuration) or with electrode positions reversed (n = 8, 'epilepsy' configuration). In awake state, HRRs were determined for each combination of pulse frequency (2-20 Hz), intensity (0-3.5 mA) and pulse widths (130-750 μs) over 14 months. At low intensities and higher frequency VNS, HR increased during the VNS active phase owing to afferent modulation of parasympathetic central drive. When functional effects of afferent and efferent fibre activation were balanced, a null HRR was evoked (defined as 'neural fulcrum') during which HRR ≈ 0. As intensity increased further, HR was reduced during the active phase of VNS. While qualitatively similar, VNS delivered in the epilepsy configuration resulted in more pronounced HR acceleration and reduced HR deceleration during VNS. At termination, under anaesthesia, transection of the vagi rostral to the stimulation site eliminated the augmenting response to VNS and enhanced the parasympathetic efferent-mediated suppressing effect on electrical and mechanical function of the heart. In conclusion, VNS activates central then peripheral aspects of the cardiac nervous system. VNS control over cardiac function is maintained during chronic therapy.
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Affiliation(s)
- Jeffrey L Ardell
- UCLA Neurocardiology Research Center of Excellence and UCLA Cardiac Arrhythmia Center, Los Angeles, Los Angeles, CA, USA
| | - Heath Nier
- Biomedical Sciences, East Tennessee State University, Johnson City, TN, USA
| | - Matthew Hammer
- UCLA Neurocardiology Research Center of Excellence and UCLA Cardiac Arrhythmia Center, Los Angeles, Los Angeles, CA, USA
| | | | | | - Eric Beaumont
- Biomedical Sciences, East Tennessee State University, Johnson City, TN, USA
| | | | - J Andrew Armour
- UCLA Neurocardiology Research Center of Excellence and UCLA Cardiac Arrhythmia Center, Los Angeles, Los Angeles, CA, USA
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24
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Kember G, Ardell JL, Shivkumar K, Armour JA. Recurrent myocardial infarction: Mechanisms of free-floating adaptation and autonomic derangement in networked cardiac neural control. PLoS One 2017; 12:e0180194. [PMID: 28692680 PMCID: PMC5503241 DOI: 10.1371/journal.pone.0180194] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 06/12/2017] [Indexed: 12/20/2022] Open
Abstract
The cardiac nervous system continuously controls cardiac function whether or not pathology is present. While myocardial infarction typically has a major and catastrophic impact, population studies have shown that longer-term risk for recurrent myocardial infarction and the related potential for sudden cardiac death depends mainly upon standard atherosclerotic variables and autonomic nervous system maladaptations. Investigative neurocardiology has demonstrated that autonomic control of cardiac function includes local circuit neurons for networked control within the peripheral nervous system. The structural and adaptive characteristics of such networked interactions define the dynamics and a new normal for cardiac control that results in the aftermath of recurrent myocardial infarction and/or unstable angina that may or may not precipitate autonomic derangement. These features are explored here via a mathematical model of cardiac regulation. A main observation is that the control environment during pathology is an extrapolation to a setting outside prior experience. Although global bounds guarantee stability, the resulting closed-loop dynamics exhibited while the network adapts during pathology are aptly described as 'free-floating' in order to emphasize their dependence upon details of the network structure. The totality of the results provide a mechanistic reasoning that validates the clinical practice of reducing sympathetic efferent neuronal tone while aggressively targeting autonomic derangement in the treatment of ischemic heart disease.
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Affiliation(s)
- Guy Kember
- Dept. of Engineering Mathematics and Internetworking/Faculty of Engineering/Dalhousie University, Halifax, NS, Canada
- * E-mail:
| | - Jeffrey L. Ardell
- David Geffen School of Medicine/Cardiac Arrhythmia Center, University of California – Los Angeles (UCLA), Los Angeles, CA, United States of America
| | - Kalyanam Shivkumar
- David Geffen School of Medicine/Cardiac Arrhythmia Center, University of California – Los Angeles (UCLA), Los Angeles, CA, United States of America
| | - J. Andrew Armour
- David Geffen School of Medicine/Cardiac Arrhythmia Center, University of California – Los Angeles (UCLA), Los Angeles, CA, United States of America
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25
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Chui RW, Buckley U, Rajendran PS, Vrabec T, Shivkumar K, Ardell JL. Bioelectronic block of paravertebral sympathetic nerves mitigates post-myocardial infarction ventricular arrhythmias. Heart Rhythm 2017. [PMID: 28629852 DOI: 10.1016/j.hrthm.2017.06.025] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
BACKGROUND Autonomic dysfunction contributes to induction of ventricular tachyarrhythmia (VT). OBJECTIVE To determine the efficacy of charge-balanced direct current (CBDC), applied to the T1-T2 segment of the paravertebral sympathetic chain, on VT inducibility post-myocardial infarction (MI). METHODS In a porcine model, CBDC was applied in acute animals (n = 7) to optimize stimulation parameters for sympathetic blockade and in chronic MI animals (n = 7) to evaluate the potential for VTs. Chronic MI was induced by microsphere embolization of the left anterior descending coronary artery. At termination, in anesthetized animals and following thoracotomy, an epicardial sock array was placed over both ventricles and a quadripolar carousel electrode positioned underlying the right T1-T2 paravertebral chain. In acute animals, the efficacy of CBDC carousel (CBDCC) block was assessed by evaluating cardiac function during T2 paravertebral ganglion stimulation with and without CBDCC. In chronic MI animals, VT inducibility was assessed by extrasystolic (S1-S2) stimulations at baseline and under >66% CBDCC blockade of T2-evoked sympathoexcitation. RESULTS CBDCC demonstrated a current-dependent and reversible block without impacting basal cardiac function. VT was induced at baseline in all chronic MI animals. One animal died after baseline induction. Of the 6 remaining animals, only 1 was reinducible with simultaneous CBDCC application (P < .002 from baseline). The ventricular effective refractory period (VERP) was prolonged with CBDCC (323 ± 26 ms) compared to baseline (271 ± 32 ms) (P < .05). CONCLUSIONS Axonal block of the T1-T2 paravertebral chain with CBDCC reduced VT in a chronic MI model. CBDCC prolonged VERP, without altering baseline cardiac function, resulting in improved electrical stability.
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Affiliation(s)
- Ray W Chui
- University of California-Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, California; UCLA Neurocardiology Research Center of Excellence, Los Angeles, California; Molecular, Cellular & Integrative Physiology Program, UCLA, Los Angeles, California
| | - Una Buckley
- University of California-Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, California; UCLA Neurocardiology Research Center of Excellence, Los Angeles, California
| | - Pradeep S Rajendran
- University of California-Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, California; UCLA Neurocardiology Research Center of Excellence, Los Angeles, California; Molecular, Cellular & Integrative Physiology Program, UCLA, Los Angeles, California
| | - Tina Vrabec
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio
| | - Kalyanam Shivkumar
- University of California-Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, California; UCLA Neurocardiology Research Center of Excellence, Los Angeles, California; Molecular, Cellular & Integrative Physiology Program, UCLA, Los Angeles, California
| | - Jeffrey L Ardell
- University of California-Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, California; UCLA Neurocardiology Research Center of Excellence, Los Angeles, California; Molecular, Cellular & Integrative Physiology Program, UCLA, Los Angeles, California.
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26
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The role of the autonomic nervous system in arrhythmias and sudden cardiac death. Auton Neurosci 2017; 205:1-11. [PMID: 28392310 DOI: 10.1016/j.autneu.2017.03.005] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 03/11/2017] [Accepted: 03/28/2017] [Indexed: 12/16/2022]
Abstract
The autonomic nervous system (ANS) is complex and plays an important role in cardiac arrhythmia pathogenesis. A deeper understanding of the anatomy and development of the ANS has shed light on its involvement in cardiac arrhythmias. Alterations in levels of Sema-3a and NGF, both growth factors involved in innervation patterning during development of the ANS, leads to cardiac arrhythmias. Dysregulation of the ANS, including polymorphisms in genes involved in ANS development, have been implicated in sudden infant death syndrome. Disruptions in the sympathetic and/or parasympathetic systems of the ANS can lead to cardiac arrhythmias and can vary depending on the type of arrhythmia. Simultaneous stimulation of both the sympathetic and parasympathetic systems is thought to lead to atrial fibrillation whereas increased sympathetic stimulation is thought to lead to ventricular fibrillation or ventricular tachycardia. In inherited arrhythmia syndromes, such as Long QT and Catecholaminergic Polymorphic Ventricular Tachycardia, sympathetic system stimulation is thought to lead to ventricular tachycardia, subsequent arrhythmias, and in severe cases, cardiac death. On the other hand, arrhythmic events in Brugada Syndrome have been associated with periods of high parasympathetic tone. Increasing evidence suggests that modulation of the ANS as a therapeutic strategy in the treatment of cardiac arrhythmias is safe and effective. Further studies investigating the involvement of the ANS in arrhythmia pathogenesis and its modulation for the treatment of cardiac arrhythmias is warranted.
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27
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Abstract
Numerous animal cardiac exercise models using animal subjects have been established to uncover the cardiovascular physiological mechanism of exercise or to determine the effects of exercise on cardiovascular health and disease. In most cases, animal-based cardiovascular exercise modalities include treadmill running, swimming, and voluntary wheel running with a series of intensities, times, and durations. Those used animals include small rodents (e.g., mice and rats) and large animals (e.g., rabbits, dogs, goats, sheep, pigs, and horses). Depending on the research goal, each experimental protocol should also describe whether its respective exercise treatment can produce the anticipated acute or chronic cardiovascular adaptive response. In this chapter, we will briefly describe the most common kinds of animal models of acute and chronic cardiovascular exercises that are currently being conducted and are likely to be chosen in the near future. Strengths and weakness of animal-based cardiac exercise modalities are also discussed.
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Abstract
Cardiac control is mediated via a series of reflex control networks involving somata in the (i) intrinsic cardiac ganglia (heart), (ii) intrathoracic extracardiac ganglia (stellate, middle cervical), (iii) superior cervical ganglia, (iv) spinal cord, (v) brainstem, and (vi) higher centers. Each of these processing centers contains afferent, efferent, and local circuit neurons, which interact locally and in an interdependent fashion with the other levels to coordinate regional cardiac electrical and mechanical indices on a beat-to-beat basis. This control system is optimized to respond to normal physiological stressors (standing, exercise, and temperature); however, it can be catastrophically disrupted by pathological events such as myocardial ischemia. In fact, it is now recognized that autonomic dysregulation is central to the evolution of heart failure and arrhythmias. Autonomic regulation therapy is an emerging modality in the management of acute and chronic cardiac pathologies. Neuromodulation-based approaches that target select nexus points of this hierarchy for cardiac control offer unique opportunities to positively affect therapeutic outcomes via improved efficacy of cardiovascular reflex control. As such, understanding the anatomical and physiological basis for such control is necessary to implement effectively novel neuromodulation therapies. © 2016 American Physiological Society. Compr Physiol 6:1635-1653, 2016.
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Affiliation(s)
- Jeffrey L Ardell
- Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, University of California, Los Angeles, California, USA.,UCLA Neurocardiology Research Center of Excellence, David Geffen School of Medicine, Los Angeles, California, USA
| | - John Andrew Armour
- Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, University of California, Los Angeles, California, USA.,UCLA Neurocardiology Research Center of Excellence, David Geffen School of Medicine, Los Angeles, California, USA
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29
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Ardell JL, Andresen MC, Armour JA, Billman GE, Chen PS, Foreman RD, Herring N, O'Leary DS, Sabbah HN, Schultz HD, Sunagawa K, Zucker IH. Translational neurocardiology: preclinical models and cardioneural integrative aspects. J Physiol 2016; 594:3877-909. [PMID: 27098459 DOI: 10.1113/jp271869] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 03/14/2016] [Indexed: 12/15/2022] Open
Abstract
Neuronal elements distributed throughout the cardiac nervous system, from the level of the insular cortex to the intrinsic cardiac nervous system, are in constant communication with one another to ensure that cardiac output matches the dynamic process of regional blood flow demand. Neural elements in their various 'levels' become differentially recruited in the transduction of sensory inputs arising from the heart, major vessels, other visceral organs and somatic structures to optimize neuronal coordination of regional cardiac function. This White Paper will review the relevant aspects of the structural and functional organization for autonomic control of the heart in normal conditions, how these systems remodel/adapt during cardiac disease, and finally how such knowledge can be leveraged in the evolving realm of autonomic regulation therapy for cardiac therapeutics.
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Affiliation(s)
- J L Ardell
- University of California - Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, CA, USA.,UCLA Neurocardiology Research Center of Excellence, David Geffen School of Medicine, Los Angeles, CA, USA
| | - M C Andresen
- Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, OR, USA
| | - J A Armour
- University of California - Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, CA, USA.,UCLA Neurocardiology Research Center of Excellence, David Geffen School of Medicine, Los Angeles, CA, USA
| | - G E Billman
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, USA
| | - P-S Chen
- The Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - R D Foreman
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - N Herring
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - D S O'Leary
- Department of Physiology, Wayne State University, Detroit, MI, USA
| | - H N Sabbah
- Department of Medicine, Henry Ford Hospital, Detroit, MI, USA
| | - H D Schultz
- Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - K Sunagawa
- Department of Cardiovascular Medicine, Kyushu University, Fukuoka, Japan
| | - I H Zucker
- Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA
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Bonilla IM, Nishijima Y, Vargas-Pinto P, Baine SH, Sridhar A, Li C, Billman GE, Carnes CA. Chronic Omega-3 Polyunsaturated Fatty Acid Treatment Variably Affects Cellular Repolarization in a Healed Post-MI Arrhythmia Model. Front Physiol 2016; 7:225. [PMID: 27378936 PMCID: PMC4906012 DOI: 10.3389/fphys.2016.00225] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 05/30/2016] [Indexed: 01/22/2023] Open
Abstract
Introduction: Over the last 40 years omega-3 polyunsaturated fatty acids (PUFAs) have been shown to be anti-arrhythmic or pro-arrhythmic depending on the method and duration of administration and model studied. We previously reported that omega-3 PUFAs do not confer anti-arrhythmic properties and are pro-arrhythmic in canine model of sudden cardiac death (SCD). Here, we evaluated the effects of chronic omega-3 PUFA treatment in post-MI animals susceptible (VF+) or resistant (VF−) to ventricular tachyarrhythmias. Methods: Perforated patch clamp techniques were used to measure cardiomyocyte action potential durations (APD) at 50 and 90% repolarization and short term variability of repolarization. The early repolarizing transient outward potassium current Ito was also studied. Results: Omega-3 PUFAs prolonged the action potential in VF− myocytes at both 50 and 90% repolarization. Short term variability of repolarization was increased in both untreated and treated VF− myocytes vs. controls. Ito was unaffected by omega-3 PUFA treatment. Omega-3 PUFA treatment attenuated the action potential prolongation in VF+ myocytes, but did not return repolarization to control values. Conclusions: Omega-3 PUFAs do not confer anti-arrhythmic properties in the setting of healed myocardial infarction in a canine model of SCD. In canines previously resistant to ventricular fibrillation (VF−), omega-3 PUFA treatment prolonged the action potential in VF− myocytes, and may contribute to pro-arrhythmic responses.
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Affiliation(s)
- Ingrid M Bonilla
- College of Pharmacy, The Ohio State UniversityColumbus, OH, USA; Department of Physiology and Cell Biology, The Ohio State UniversityColumbus, OH, USA; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State UniversityColumbus, OH, USA
| | | | - Pedro Vargas-Pinto
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University Columbus, OH, USA
| | - Stephen H Baine
- College of Pharmacy, The Ohio State University Columbus, OH, USA
| | - Arun Sridhar
- College of Pharmacy, The Ohio State University Columbus, OH, USA
| | - Chun Li
- Division of Cardiology, Peking University People's Hospital Beijing, China
| | - George E Billman
- Department of Physiology and Cell Biology, The Ohio State UniversityColumbus, OH, USA; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State UniversityColumbus, OH, USA
| | - Cynthia A Carnes
- College of Pharmacy, The Ohio State UniversityColumbus, OH, USA; Department of Physiology and Cell Biology, The Ohio State UniversityColumbus, OH, USA; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State UniversityColumbus, OH, USA
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31
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Nederend I, Jongbloed MRM, de Geus EJC, Blom NA, Ten Harkel ADJ. Postnatal Cardiac Autonomic Nervous Control in Pediatric Congenital Heart Disease. J Cardiovasc Dev Dis 2016; 3:jcdd3020016. [PMID: 29367565 PMCID: PMC5715679 DOI: 10.3390/jcdd3020016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 03/30/2016] [Accepted: 04/09/2016] [Indexed: 12/16/2022] Open
Abstract
Congenital heart disease is the most common congenital defect. During childhood, survival is generally good but, in adulthood, late complications are not uncommon. Abnormal autonomic control in children with congenital heart disease may contribute considerably to the pathophysiology of these long term sequelae. This narrative review of 34 studies aims to summarize current knowledge on function of the autonomic nervous system in children with a congenital heart defect. Large scale studies that measure both branches of the nervous system for prolonged periods of time in well-defined patient cohorts in various phases of childhood and adolescence are currently lacking. Pending such studies, there is not yet a good grasp on the extent and direction of sympathetic and parasympathetic autonomic function in pediatric congenital heart disease. Longitudinal studies in homogenous patient groups linking autonomic nervous system function and clinical outcome are warranted.
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Affiliation(s)
- Ineke Nederend
- Department of Biological Psychology, Faculty of Behavioral and Movement sciences, VU Amsterdam, Van der Boechorststraat 1, 1081 BT Amsterdam, The Netherlands.
- EMGO+ Institute for Health and Care Research, VU Medical Center Amsterdam, Van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands.
- Department of Pediatric Cardiology, LUMC University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands.
| | - Monique R M Jongbloed
- Department of Cardiology and Anatomy & Embryology, LUMC University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands.
| | - Eco J C de Geus
- Department of Biological Psychology, Faculty of Behavioral and Movement sciences, VU Amsterdam, Van der Boechorststraat 1, 1081 BT Amsterdam, The Netherlands.
- EMGO+ Institute for Health and Care Research, VU Medical Center Amsterdam, Van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands.
| | - Nico A Blom
- Department of Pediatric Cardiology, LUMC University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands.
| | - Arend D J Ten Harkel
- Department of Pediatric Cardiology, LUMC University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands.
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Abstract
Autonomic regulation therapy (ART) is a rapidly emerging therapy in the management of congestive heart failure secondary to systolic dysfunction. Modulation of the cardiac neuronal hierarchy can be achieved with bioelectronics modulation of the spinal cord, cervical vagus, baroreceptor, or renal nerve ablation. This review will discuss relevant preclinical and clinical research in ART for systolic heart failure. Understanding mechanistically what is being stimulated within the autonomic nervous system by such device-based therapy and how the system reacts to such stimuli is essential for optimizing stimulation parameters and for the future development of effective ART.
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33
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Canan BD, Haizlip KM, Xu Y, Monasky MM, Hiranandani N, Milani-Nejad N, Varian KD, Slabaugh JL, Schultz EJ, Fedorov VV, Billman GE, Janssen PML. Effect of exercise training and myocardial infarction on force development and contractile kinetics in isolated canine myocardium. J Appl Physiol (1985) 2016; 120:817-24. [PMID: 26823341 DOI: 10.1152/japplphysiol.00775.2015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 01/27/2016] [Indexed: 12/20/2022] Open
Abstract
It is well known that moderate exercise training elicits a small increase in ventricular mass (i.e., a physiological hypertrophy) that has many beneficial effects on overall cardiac health. It is also well known that, when a myocardial infarction damages part of the heart, the remaining myocardium remodels to compensate for the loss of viable functioning myocardium. The effects of exercise training, myocardial infarction (MI), and their interaction on the contractile performance of the myocardium itself remain largely to be determined. The present study investigated the contractile properties and kinetics of right ventricular myocardium isolated from sedentary and exercise trained (10-12 wk progressively increasing treadmill running, begun 4 wk after MI induction) dogs with and without a left ventricular myocardial infarction. Exercise training increased force development, whereas MI decreased force development that was not improved by exercise training. Contractile kinetics were significantly slower in the trained dogs, whereas this impact of training was less or no longer present after MI. Length-dependent activation, both evaluated on contractile force and kinetics, was similar in all four groups. The control exercise-trained group exhibited a more positive force-frequency relationship compared with the sedentary control group while both sedentary and trained post-MI dogs had a more negative relationship. Last, the impact of the β-adrenergic receptor agonist isoproterenol resulted in a similar increase in force and acceleration of contractile kinetics in all groups. Thus, exercise training increased developed force but slowed contractile kinetics in control (noninfarcted animals), actions that were attenuated or completely absent in post-MI dogs.
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Affiliation(s)
- Benjamin D Canan
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio; and
| | - Kaylan M Haizlip
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio; and
| | - Ying Xu
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio; and
| | - Michelle M Monasky
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio; and
| | - Nitisha Hiranandani
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio; and
| | - Nima Milani-Nejad
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio; and
| | - Kenneth D Varian
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio; and
| | - Jessica L Slabaugh
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio; and
| | - Eric J Schultz
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio; and
| | - Vadim V Fedorov
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio; and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| | - George E Billman
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio; and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| | - Paul M L Janssen
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio; and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
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34
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Cardiac Sympathetic Nerve Sprouting and Susceptibility to Ventricular Arrhythmias after Myocardial Infarction. Cardiol Res Pract 2015; 2015:698368. [PMID: 26793403 PMCID: PMC4697091 DOI: 10.1155/2015/698368] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 12/02/2015] [Indexed: 12/04/2022] Open
Abstract
Ventricular arrhythmogenesis is thought to be a common cause of sudden cardiac death following myocardial infarction (MI). Nerve remodeling as a result of MI is known to be an important genesis of life-threatening arrhythmias. It is hypothesized that neural modulation might serve as a therapeutic option of malignant arrhythmias. In fact, left stellectomy or β-blocker therapy is shown to be effective in the prevention of ventricular tachyarrhythmias (VT), ventricular fibrillation (VF), and sudden cardiac death (SCD) after MI both in patients and in animal models. Results from decades of research already evidenced a positive relationship between abnormal nerve density and ventricular arrhythmias after MI. In this review, we summarized the molecular mechanisms involved in cardiac sympathetic rejuvenation and mechanisms related to sympathetic hyperinnervation and arrhythmogenesis after MI and analyzed the potential therapeutic implications of nerve sprouting modification for ventricular arrhythmias and SCD control.
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35
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Rajendran PS, Nakamura K, Ajijola OA, Vaseghi M, Armour JA, Ardell JL, Shivkumar K. Myocardial infarction induces structural and functional remodelling of the intrinsic cardiac nervous system. J Physiol 2015; 594:321-41. [PMID: 26572244 DOI: 10.1113/jp271165] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2015] [Accepted: 11/12/2015] [Indexed: 12/14/2022] Open
Abstract
KEY POINTS Intrinsic cardiac (IC) neurons undergo differential morphological and phenotypic remodelling that reflects the site of myocardial infarction (MI). Afferent neural signals from the infarcted region to IC neurons are attenuated, while those from border and remote regions are preserved post-MI, giving rise to a 'neural sensory border zone'. Convergent IC local circuit (processing) neurons have enhanced transduction capacity following MI. Functional network connectivity within the intrinsic cardiac nervous system is reduced post-MI. MI reduces the response and alters the characteristics of IC neurons to ventricular pacing. ABSTRACT Autonomic dysregulation following myocardial infarction (MI) is an important pathogenic event. The intrinsic cardiac nervous system (ICNS) is a neural network located on the heart that is critically involved in autonomic regulation. The aims of this study were to characterize structural and functional remodelling of the ICNS post-MI in a porcine model (control (n = 16) vs. healed anteroapical MI (n = 16)). In vivo microelectrode recordings of basal activity, as well as responses to afferent and efferent stimuli, were recorded from intrinsic cardiac neurons. From control 118 neurons and from MI animals 102 neurons were functionally classified as afferent, efferent, or convergent (receiving both afferent and efferent inputs). In control and MI, convergent neurons represented the largest subpopulation (47% and 48%, respectively) and had enhanced transduction capacity following MI. Efferent inputs to neurons were maintained post-MI. Afferent inputs were attenuated from the infarcted region (19% in control vs. 7% in MI; P = 0.03), creating a 'neural sensory border zone', or heterogeneity in afferent information. MI reduced transduction of changes in preload (54% in control vs. 41% in MI; P = 0.05). The overall functional network connectivity, or the ability of neurons to respond to independent pairs of stimuli, within the ICNS was reduced following MI. The neuronal response was differentially decreased to ventricular vs. atrial pacing post-MI (63% in control vs. 44% in MI to ventricular pacing; P < 0.01). MI induced morphological and phenotypic changes within the ICNS. The alteration of afferent neural signals, and remodelling of convergent neurons, represents a 'neural signature' of ischaemic heart disease.
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Affiliation(s)
- Pradeep S Rajendran
- University of California - Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, CA, USA.,Neurocardiology Research Center of Excellence, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA.,Molecular, Cellular & Integrative Physiology Program, UCLA, Los Angeles, CA, USA
| | - Keijiro Nakamura
- University of California - Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, CA, USA.,Neurocardiology Research Center of Excellence, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Olujimi A Ajijola
- University of California - Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, CA, USA.,Neurocardiology Research Center of Excellence, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Marmar Vaseghi
- University of California - Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, CA, USA.,Neurocardiology Research Center of Excellence, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA.,Molecular, Cellular & Integrative Physiology Program, UCLA, Los Angeles, CA, USA
| | - J Andrew Armour
- University of California - Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, CA, USA.,Neurocardiology Research Center of Excellence, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Jeffrey L Ardell
- University of California - Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, CA, USA.,Neurocardiology Research Center of Excellence, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA.,Molecular, Cellular & Integrative Physiology Program, UCLA, Los Angeles, CA, USA
| | - Kalyanam Shivkumar
- University of California - Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, CA, USA.,Neurocardiology Research Center of Excellence, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA.,Molecular, Cellular & Integrative Physiology Program, UCLA, Los Angeles, CA, USA
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36
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Beaumont E, Southerland EM, Hardwick JC, Wright GL, Ryan S, Li Y, KenKnight BH, Armour JA, Ardell JL. Vagus nerve stimulation mitigates intrinsic cardiac neuronal and adverse myocyte remodeling postmyocardial infarction. Am J Physiol Heart Circ Physiol 2015; 309:H1198-206. [PMID: 26276818 PMCID: PMC4666924 DOI: 10.1152/ajpheart.00393.2015] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 08/10/2015] [Indexed: 12/13/2022]
Abstract
This paper aims to determine whether chronic vagus nerve stimulation (VNS) mitigates myocardial infarction (MI)-induced remodeling of the intrinsic cardiac nervous system (ICNS), along with the cardiac tissue it regulates. Guinea pigs underwent VNS implantation on the right cervical vagus. Two weeks later, MI was produced by ligating the ventral descending coronary artery. VNS stimulation started 7 days post-MI (20 Hz, 0.9 ± 0.2 mA, 14 s on, 48 s off; VNS-MI, n = 7) and was compared with time-matched MI animals with sham VNS (MI n = 7) vs. untreated controls (n = 8). Echocardiograms were performed before and at 90 days post-MI. At termination, IC neuronal intracellular voltage recordings were obtained from whole-mount neuronal plexuses. MI increased left ventricular end systolic volume (LVESV) 30% (P = 0.027) and reduced LV ejection fraction (LVEF) 6.5% (P < 0.001) at 90 days post-MI compared with baseline. In the VNS-MI group, LVESV and LVEF did not differ from baseline. IC neurons showed depolarization of resting membrane potentials and increased input resistance in MI compared with VNS-MI and sham controls (P < 0.05). Neuronal excitability and sensitivity to norepinephrine increased in MI and VNS-MI groups compared with controls (P < 0.05). Synaptic efficacy, as determined by evoked responses to stimulating input axons, was reduced in VNS-MI compared with MI or controls (P < 0.05). VNS induced changes in myocytes, consistent with enhanced glycogenolysis, and blunted the MI-induced increase in the proapoptotic Bcl-2-associated X protein (P < 0.05). VNS mitigates MI-induced remodeling of the ICNS, correspondingly preserving ventricular function via both neural and cardiomyocyte-dependent actions.
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Affiliation(s)
- Eric Beaumont
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee
| | - Elizabeth M Southerland
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee
| | | | - Gary L Wright
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee
| | - Shannon Ryan
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee
| | - Ying Li
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee
| | | | - J Andrew Armour
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee; Department of Medicine, University of California Los Angeles Health System, Los Angeles, California
| | - Jeffrey L Ardell
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee; Department of Medicine, University of California Los Angeles Health System, Los Angeles, California
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37
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Van Houten JM, Wessells RJ, Lujan HL, DiCarlo SE. My gut feeling says rest: Increased intestinal permeability contributes to chronic diseases in high-intensity exercisers. Med Hypotheses 2015; 85:882-6. [PMID: 26415977 DOI: 10.1016/j.mehy.2015.09.018] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 09/12/2015] [Indexed: 12/28/2022]
Abstract
Chronic diseases are the leading cause of death and disability worldwide, and many of these conditions are linked to chronic inflammation. One potential cause of chronic inflammation is an increased intestinal epithelial permeability. Recent studies have demonstrated that parasympathetic stimulation via the efferent abdominal vagus nerve increases the expression and proper localization of tight junction proteins and decreases intestinal epithelial permeability. This finding may provide a novel approach for treating and preventing many chronic conditions. Importantly, physical activity is associated with increased resting parasympathetic (vagal) activity and lower risk of chronic diseases. However, high intensity long duration exercise can be harmful to overall health. Specifically, individuals who frequently exercise strenuously and for longer time intervals have the same mortality rates as sedentary individuals. This may be explained, in part, by longer periods of reduced vagal activity as vagal activity is markedly reduced both during and after intense exercise. We hypothesize that one mechanism by which exercise provides its health benefits is by increasing resting vagal activity and decreasing intestinal epithelial permeability, thus decreasing chronic inflammation. Additionally, we hypothesize that long periods of reduced vagal activity in individuals who exercise at high intensities and for longer durations, decrease the integrity of the intestinal barrier, putting them at greater risk of chronic inflammation and a host of chronic diseases. Thus, this hypothesis provides a conceptual link between the well-established benefits of frequent exercise and the paradoxical deleterious effects of prolonged, high-intensity exercise without adequate rest.
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Affiliation(s)
- Jason M Van Houten
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, United States
| | - Robert J Wessells
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, United States
| | - Heidi L Lujan
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, United States
| | - Stephen E DiCarlo
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, United States.
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38
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Billman GE, Cagnoli KL, Csepe T, Li N, Wright P, Mohler PJ, Fedorov VV. Exercise training-induced bradycardia: evidence for enhanced parasympathetic regulation without changes in intrinsic sinoatrial node function. J Appl Physiol (1985) 2015; 118:1344-55. [PMID: 25749448 PMCID: PMC4451292 DOI: 10.1152/japplphysiol.01111.2014] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 02/28/2015] [Indexed: 01/17/2023] Open
Abstract
The mechanisms responsible for exercise-induced reductions in baseline heart rate (HR), known as training bradycardia, remain controversial. Therefore, changes in cardiac autonomic regulation and intrinsic sinoatrial nodal (SAN) rate were evaluated using dogs randomly assigned to either a 10- to 12-wk exercise training (Ex, n = 15) or an equivalent sedentary period (Sed, n = 10). Intrinsic HR was revealed by combined autonomic nervous system (ANS) blockade (propranolol + atropine, iv) before and after completion of the study. At the end of the study, SAN function was further evaluated by examining the SAN recovery time (SNRT) following rapid atrial pacing and the response to adenosine in anesthetized animals. As expected, both the response to submaximal exercise and baseline HR significantly (P < 0.01) decreased, and heart rate variability (HRV; e.g., high-frequency R-R interval variability) significantly (P < 0.01) increased in the Ex group but did not change in the Sed group. Atropine also induced significantly (P < 0.01) greater reductions in HRV in the Ex group compared with the Sed group; propranolol elicited similar HR and HRV changes in both groups. In contrast, neither intrinsic HR (Ex before, 141.2 ± 6.7; Ex after, 146.0 ± 8.0 vs. Sed before, 143.3 ± 11.1; Sed after, 141.0 ± 11.3 beats per minute), the response to adenosine, corrected SNRT, nor atrial fibrosis and atrial fibrillation inducibility differed in the Ex group vs. the Sed group. These data suggest that in a large-animal model, training bradycardia results from an enhanced cardiac parasympathetic regulation and not from changes in intrinsic properties of the SAN.
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Affiliation(s)
- George E Billman
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio; and
| | - Kristen L Cagnoli
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio
| | - Thomas Csepe
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio
| | - Ning Li
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio
| | - Patrick Wright
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio; and
| | - Peter J Mohler
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio; and Deaprtment of Internal Medicine, The Ohio State University, Columbus, Ohio
| | - Vadim V Fedorov
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio; and
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Del Rio CL, Clymer BD, Billman GE. Myocardial electrotonic response to submaximal exercise in dogs with healed myocardial infarctions: evidence for β-adrenoceptor mediated enhanced coupling during exercise testing. Front Physiol 2015; 6:25. [PMID: 25698976 PMCID: PMC4318283 DOI: 10.3389/fphys.2015.00025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 01/15/2015] [Indexed: 11/13/2022] Open
Abstract
INTRODUCTION Autonomic neural activation during cardiac stress testing is an established risk-stratification tool in post-myocardial infarction (MI) patients. However, autonomic activation can also modulate myocardial electrotonic coupling, a known factor to contribute to the genesis of arrhythmias. The present study tested the hypothesis that exercise-induced autonomic neural activation modulates electrotonic coupling (as measured by myocardial electrical impedance, MEI) in post-MI animals shown to be susceptible or resistant to ventricular fibrillation (VF). METHODS Dogs (n = 25) with healed MI instrumented for MEI measurements were trained to run on a treadmill and classified based on their susceptibility to VF (12 susceptible, 9 resistant). MEI and ECGs were recorded during 6-stage exercise tests (18 min/test; peak: 6.4 km/h @ 16%) performed under control conditions, and following complete β-adrenoceptor (β-AR) blockade (propranolol); MEI was also measured at rest during escalating β-AR stimulation (isoproterenol) or overdrive-pacing. RESULTS Exercise progressively increased heart rate (HR) and reduced heart rate variability (HRV). In parallel, MEI decreased gradually (enhanced electrotonic coupling) with exercise; at peak exercise, MEI was reduced by 5.3 ± 0.4% (or -23 ± 1.8Ω, P < 0.001). Notably, exercise-mediated electrotonic changes were linearly predicted by the degree of autonomic activation, as indicated by changes in either HR or in HRV (P < 0.001). Indeed, β-AR blockade attenuated the MEI response to exercise while direct β-AR stimulation (at rest) triggered MEI decreases comparable to those observed during exercise; ventricular pacing had no significant effects on MEI. Finally, animals prone to VF had a significantly larger MEI response to exercise. CONCLUSIONS These data suggest that β-AR activation during exercise can acutely enhance electrotonic coupling in the myocardium, particularly in dogs susceptible to ischemia-induced VF.
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Affiliation(s)
- Carlos L Del Rio
- Department of Physiology and Cell Biology, The Ohio State University Columbus, OH, USA ; Department of Electrical and Computer Engineering, The Ohio State University Columbus, OH, USA ; Safety Pharmacology, QTest Labs Columbus, OH, USA
| | - Bradley D Clymer
- Department of Electrical and Computer Engineering, The Ohio State University Columbus, OH, USA ; Biomedical Engineering, The Ohio State University Columbus, OH, USA
| | - George E Billman
- Department of Physiology and Cell Biology, The Ohio State University Columbus, OH, USA ; Davis Heart and Lung Research Institute, The Ohio State University Columbus, OH, USA
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Wengrowski AM, Wang X, Tapa S, Posnack NG, Mendelowitz D, Kay MW. Optogenetic release of norepinephrine from cardiac sympathetic neurons alters mechanical and electrical function. Cardiovasc Res 2014; 105:143-50. [PMID: 25514932 DOI: 10.1093/cvr/cvu258] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
AIMS Release of norepinephrine (NE) from sympathetic neurons enhances heart rate (HR) and developed force through activation of β-adrenergic receptors, and this sympathoexcitation is a key risk for the generation of cardiac arrhythmias. Studies of β-adrenergic modulation of cardiac function typically involve the administration of exogenous β-adrenergic receptor agonists to directly elicit global β-adrenergic receptor activation by bypassing the involvement of sympathetic nerve terminals. In this work, we use a novel method to activate sympathetic fibres within the myocardium of Langendorff-perfused hearts while measuring changes in electrical and mechanical function. METHODS AND RESULTS The light-activated optogenetic protein channelrhodopsin-2 (ChR2) was expressed in murine catecholaminergic sympathetic neurons. Sympathetic fibres were then photoactivated to examine changes in contractile force, HR, and cardiac electrical activity. Incidence of arrhythmia was measured with and without exposure to photoactivation of sympathetic fibres, and hearts were optically mapped to detect changes in action potential durations and conduction velocities. Results demonstrate facilitation of both developed force and HR after photostimulated release of NE, with increases in contractile force and HR of 34.5 ± 5.5 and 25.0 ± 9.3%, respectively. Photostimulation of sympathetic fibres also made hearts more susceptible to arrhythmia, with greater incidence and severity. In addition, optically mapped action potentials displayed a small but significant shortening of the plateau phase (-5.5 ± 1.0 ms) after photostimulation. CONCLUSION This study characterizes a powerful and clinically relevant new model for studies of cardiac arrhythmias generated by increasing the activity of sympathetic nerve terminals and the resulting activation of myocyte β-adrenergic receptors.
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Affiliation(s)
- Anastasia M Wengrowski
- Department of Biomedical Engineering, The George Washington University, Phillips Hall, Room 607, 801 22nd Street NW, Washington, DC 20052, USA
| | - Xin Wang
- Department of Pharmacology and Physiology, The George Washington University, Washington, DC, USA
| | - Srinivas Tapa
- Department of Biomedical Engineering, The George Washington University, Phillips Hall, Room 607, 801 22nd Street NW, Washington, DC 20052, USA
| | - Nikki Gillum Posnack
- Department of Pharmacology and Physiology, The George Washington University, Washington, DC, USA
| | - David Mendelowitz
- Department of Pharmacology and Physiology, The George Washington University, Washington, DC, USA
| | - Matthew W Kay
- Department of Biomedical Engineering, The George Washington University, Phillips Hall, Room 607, 801 22nd Street NW, Washington, DC 20052, USA Department of Pharmacology and Physiology, The George Washington University, Washington, DC, USA
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Hepatocyte growth factor modification enhances the anti-arrhythmic properties of human bone marrow-derived mesenchymal stem cells. PLoS One 2014; 9:e111246. [PMID: 25360679 PMCID: PMC4216066 DOI: 10.1371/journal.pone.0111246] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2014] [Accepted: 09/17/2014] [Indexed: 12/15/2022] Open
Abstract
Background/Aims Chronic myocardial infarction (MI) results in the formation of arrhythmogenic substrates, causing lethal ventricular arrhythmia (VA). We aimed to determine whether mesenchymal stem cells (MSCs) carrying a hepatocyte growth factor (HGF) gene modification (HGF-MSCs) decrease the levels of arrhythmogenic substrates and reduce the susceptibility to developing VA compared with unmodified MSCs and PBS in a swine infarction model. Methods The left descending anterior artery was balloon-occluded to establish an MI model. Four weeks later, the randomly grouped pigs were administered MSCs, PBS or HGF-MSCs via thoracotomy. After an additional four weeks, dynamic electrocardiography was performed to assess heart rate variability, and programmed electrical stimulation was conducted to evaluate the risk for VA. Then, the pigs were euthanized for morphometric, immunofluorescence and western blot analyses. Results: The HGF-MSC group displayed the highest vessel density and Cx43 expression levels, and the lowest levels of apoptosis, and tyrosine hydroxylase (TH) and growth associated protein 43 (GAP43) expression. Moreover, the HGF-MSC group exhibited a decrease in the number of sympathetic nerve fibers, substantial decreases in the low frequency and the low-/high- frequency ratio and increases in the root mean square of successive differences (rMSSD) and the percentage of successive normal sinus R-R intervals longer than 50 ms (pNN50), compared with the other two groups. Finally, the HGF-MSC group displayed the lowest susceptibility to developing VA. Conclusion HGF-MSCs displayed potent antiarrhythmic effects, reducing the risk for VA.
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Eyre ELJ, Duncan MJ, Birch SL, Fisher JP. The influence of age and weight status on cardiac autonomic control in healthy children: a review. Auton Neurosci 2014; 186:8-21. [PMID: 25458714 DOI: 10.1016/j.autneu.2014.09.019] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 08/12/2014] [Accepted: 09/25/2014] [Indexed: 01/01/2023]
Abstract
Heart rate variability (HRV) analyses can provide a non-invasive evaluation of cardiac autonomic activity. How autonomic control normally develops in childhood and how this is affected by obesity remain incompletely understood. In this review we examine the evidence that childhood age and weight status influence autonomic control of the heart as assessed using HRV. Electronic databases (Pubmed, EMBASE and Cochrane Library) were searched for studies examining HRV in healthy children from birth to 18 years who adhered to the Task Force (1996) guidelines. Twenty-four studies met our inclusion criteria. Seven examined childhood age and HRV. A reduction in 24-hour LF:HF was reported from birth to infancy (1 year), while overall HRV (SDNN) showed a marked and progressive increase. From infancy to early-to-late childhood (from 12 months to 15 years) LF:HF ratio was reported to decline further albeit at a slower rate, while RMSSD and SDNN increased. Twenty studies examined the effects of weight status and body composition on HRV. In a majority of studies, obese children exhibited reductions in RMSSD (n = 8/13), pNN50% (n = 7/9) and HF power (n = 14/18), no difference was reported for LF (n = 10/18), while LF:HF ratio was elevated (n = 10/15). HRV changes during childhood are consistent with a marked and progressive increase in cardiac parasympathetic activity relative to sympathetic activity. Obesity disrupts the normal maturation of cardiac autonomic control.
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Affiliation(s)
- E L J Eyre
- Department of Applied Science and Health, Biological and Exercise Sciences, Coventry University, James Starley Building, Priory Street, Coventry CV1 5FB, United Kingdom.
| | - M J Duncan
- Department of Applied Science and Health, Biological and Exercise Sciences, Coventry University, James Starley Building, Priory Street, Coventry CV1 5FB, United Kingdom
| | - S L Birch
- Department of Applied Science and Health, Biological and Exercise Sciences, Coventry University, James Starley Building, Priory Street, Coventry CV1 5FB, United Kingdom
| | - J P Fisher
- School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
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Silvani A, Berteotti C, Bastianini S, Cohen G, Lo Martire V, Mazza R, Pagotto U, Quarta C, Zoccoli G. Cardiorespiratory anomalies in mice lacking CB1 cannabinoid receptors. PLoS One 2014; 9:e100536. [PMID: 24950219 PMCID: PMC4065065 DOI: 10.1371/journal.pone.0100536] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 05/26/2014] [Indexed: 11/30/2022] Open
Abstract
Cannabinoid type 1 (CB1) receptors are expressed in the nervous and cardiovascular systems. In mice, CB1 receptor deficiency protects from metabolic consequences of a high-fat diet (HFD), increases sympathetic activity to brown fat, and entails sleep anomalies. We investigated whether sleep-wake and diet-dependent cardiorespiratory control is altered in mice lacking CB1 receptors. CB1 receptor knock-out (KO) and intact wild-type (WT) mice were fed standard diet or a HFD for 3 months, and implanted with a telemetric arterial pressure transducer and electrodes for sleep scoring. Sleep state was assessed together with arterial pressure and heart rate (home cage), or breathing (whole-body plethysmograph). Increases in arterial pressure and heart rate on passing from the light (rest) to the dark (activity) period in the KO were significantly enhanced compared with the WT. These increases were unaffected by cardiac (β1) or vascular (α1) adrenergic blockade. The breathing rhythm of the KO during sleep was also more irregular than that of the WT. A HFD increased heart rate, impaired cardiac vagal modulation, and blunted the central autonomic cardiac control during sleep. A HFD also decreased cardiac baroreflex sensitivity in the KO but not in the WT. In conclusion, we performed the first systematic study of cardiovascular function in CB1 receptor deficient mice during spontaneous wake-sleep behavior, and demonstrated that CB1 receptor KO alters cardiorespiratory control particularly in the presence of a HFD. The CB1 receptor signaling may thus play a role in physiological cardiorespiratory regulation and protect from some adverse cardiovascular consequences of a HFD.
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Affiliation(s)
- Alessandro Silvani
- PRISM Lab, Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum – University of Bologna, Bologna, Italy
| | - Chiara Berteotti
- PRISM Lab, Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum – University of Bologna, Bologna, Italy
| | - Stefano Bastianini
- PRISM Lab, Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum – University of Bologna, Bologna, Italy
| | - Gary Cohen
- Department of Women & Child Health, Karolinska Institutet, Stockholm, Sweden
| | - Viviana Lo Martire
- PRISM Lab, Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum – University of Bologna, Bologna, Italy
| | - Roberta Mazza
- Endocrinology Unit and Center for Applied Biomedical Research, Department of Medical and Surgical Sciences, S. Orsola University Hospital, Alma Mater Studiorum – University of Bologna, Bologna, Italy
| | - Uberto Pagotto
- Endocrinology Unit and Center for Applied Biomedical Research, Department of Medical and Surgical Sciences, S. Orsola University Hospital, Alma Mater Studiorum – University of Bologna, Bologna, Italy
| | - Carmelo Quarta
- Endocrinology Unit and Center for Applied Biomedical Research, Department of Medical and Surgical Sciences, S. Orsola University Hospital, Alma Mater Studiorum – University of Bologna, Bologna, Italy
| | - Giovanna Zoccoli
- PRISM Lab, Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum – University of Bologna, Bologna, Italy
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Merchant FM, Sayadi O, Moazzami K, Puppala D, Armoundas AA. T-wave alternans as an arrhythmic risk stratifier: state of the art. Curr Cardiol Rep 2014; 15:398. [PMID: 23881581 DOI: 10.1007/s11886-013-0398-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Microvolt level T-wave alternans (MTWA), a phenomenon of beat-to-beat variability in the repolarization phase of the ventricles, has been closely associated with an increased risk of ventricular tachyarrhythmic events (VTE) and sudden cardiac death (SCD) during medium- and long-term follow-up. Recent observations also suggest that heightened MTWA magnitude may be closely associated with short-term risk of impending VTE. At the subcellular and cellular level, perturbations in calcium transport processes likely play a primary role in the genesis of alternans, which then secondarily lead to alternans of action potential morphology and duration (APD). As such, MTWA may play a role not only in risk stratification but also more fundamentally in the pathogenesis of VTE. In this paper, we outline recent advances in understanding the pathogenesis of MTWA and also the utility of T-wave alternans testing for clinical risk stratification. We also highlight emerging clinical applications for MTWA.
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Affiliation(s)
- Faisal M Merchant
- Cardiology Division, Emory University School of Medicine, Atlanta, GA, USA
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Milani-Nejad N, Janssen PML. Small and large animal models in cardiac contraction research: advantages and disadvantages. Pharmacol Ther 2014; 141:235-49. [PMID: 24140081 PMCID: PMC3947198 DOI: 10.1016/j.pharmthera.2013.10.007] [Citation(s) in RCA: 295] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 08/15/2013] [Indexed: 12/22/2022]
Abstract
The mammalian heart is responsible for not only pumping blood throughout the body but also adjusting this pumping activity quickly depending upon sudden changes in the metabolic demands of the body. For the most part, the human heart is capable of performing its duties without complications; however, throughout many decades of use, at some point this system encounters problems. Research into the heart's activities during healthy states and during adverse impacts that occur in disease states is necessary in order to strategize novel treatment options to ultimately prolong and improve patients' lives. Animal models are an important aspect of cardiac research where a variety of cardiac processes and therapeutic targets can be studied. However, there are differences between the heart of a human being and an animal and depending on the specific animal, these differences can become more pronounced and in certain cases limiting. There is no ideal animal model available for cardiac research, the use of each animal model is accompanied with its own set of advantages and disadvantages. In this review, we will discuss these advantages and disadvantages of commonly used laboratory animals including mouse, rat, rabbit, canine, swine, and sheep. Since the goal of cardiac research is to enhance our understanding of human health and disease and help improve clinical outcomes, we will also discuss the role of human cardiac tissue in cardiac research. This review will focus on the cardiac ventricular contractile and relaxation kinetics of humans and animal models in order to illustrate these differences.
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Affiliation(s)
- Nima Milani-Nejad
- Department of Physiology and Cell Biology and D. Davis Heart Lung Institute, College of Medicine, The Ohio State University, OH, USA
| | - Paul M L Janssen
- Department of Physiology and Cell Biology and D. Davis Heart Lung Institute, College of Medicine, The Ohio State University, OH, USA.
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Fiuza-Luces C, Garatachea N, Berger NA, Lucia A. Exercise is the real polypill. Physiology (Bethesda) 2014; 28:330-58. [PMID: 23997192 DOI: 10.1152/physiol.00019.2013] [Citation(s) in RCA: 312] [Impact Index Per Article: 31.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The concept of a "polypill" is receiving growing attention to prevent cardiovascular disease. Yet similar if not overall higher benefits are achievable with regular exercise, a drug-free intervention for which our genome has been haped over evolution. Compared with drugs, exercise is available at low cost and relatively free of adverse effects. We summarize epidemiological evidence on the preventive/therapeutic benefits of exercise and on the main biological mediators involved.
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Hardwick JC, Ryan SE, Beaumont E, Ardell JL, Southerland EM. Dynamic remodeling of the guinea pig intrinsic cardiac plexus induced by chronic myocardial infarction. Auton Neurosci 2013; 181:4-12. [PMID: 24220238 DOI: 10.1016/j.autneu.2013.10.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 10/19/2013] [Accepted: 10/23/2013] [Indexed: 11/19/2022]
Abstract
Myocardial infarction (MI) is associated with remodeling of the heart and neurohumoral control systems. The objective of this study was to define time-dependent changes in intrinsic cardiac (IC) neuronal excitability, synaptic efficacy, and neurochemical modulation following MI. MI was produced in guinea pigs by ligation of the coronary artery and associated vein on the dorsal surface of the heart. Animals were recovered for 4, 7, 14, or 50 days. Intracellular voltage recordings were obtained in whole mounts of the cardiac neuronal plexus to determine passive and active neuronal properties of IC neurons. Immunohistochemical analysis demonstrated an immediate and persistent increase in the percentage of IC neurons immunoreactive for neuronal nitric oxide synthase. Examination of individual neuronal properties demonstrated that after hyperpolarizing potentials were significantly decreased in both amplitude and time course of recovery at 7 days post-MI. These parameters returned to control values by 50 days post-MI. Synaptic efficacy, as determined by the stimulation of axonal inputs, was enhanced at 7 days post-MI only. Neuronal excitability in absence of agonist challenge was unchanged following MI. Norepinephrine increased IC excitability to intracellular current injections, a response that was augmented post-MI. Angiotensin II potentiation of norepinephrine and bethanechol-induced excitability, evident in controls, was abolished post-MI. This study demonstrates that MI induces both persistent and transient changes in IC neuronal functions immediately following injury. Alterations in the IC neuronal network, which persist for weeks after the initial insult, may lead to alterations in autonomic signaling and cardiac control.
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Affiliation(s)
- Jean C Hardwick
- Department of Biology, Ithaca College, Ithaca, NY 14850, United States.
| | - Shannon E Ryan
- Department of Biology, Ithaca College, Ithaca, NY 14850, United States
| | - Eric Beaumont
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614, United States
| | - Jeffrey L Ardell
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614, United States
| | - E Marie Southerland
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614, United States
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Belevych AE, Ho HT, Terentyeva R, Bonilla IM, Terentyev D, Carnes CA, Gyorke S, Billman GE. Dietary omega-3 fatty acids promote arrhythmogenic remodeling of cellular Ca2+ handling in a postinfarction model of sudden cardiac death. PLoS One 2013; 8:e78414. [PMID: 24205228 PMCID: PMC3799693 DOI: 10.1371/journal.pone.0078414] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 09/20/2013] [Indexed: 11/18/2022] Open
Abstract
It has been proposed that dietary omega-3 polyunsaturated fatty acids (n-3 PUFAs) can reduce the risk of ventricular arrhythmias in post-MI patients. Abnormal Ca(2+) handling has been implicated in the genesis of post-MI ventricular arrhythmias. Therefore, we tested the hypothesis that dietary n-3 PUFAs alter the vulnerability of ventricular myocytes to cellular arrhythmia by stabilizing intracellular Ca(2+) cycling. To test this hypothesis, we used a canine model of post-MI ventricular fibrillation (VF) and assigned the animals to either placebo (1 g/day corn oil) or n-3 PUFAs (1-4 g/day) groups. Using Ca(2+) imaging techniques, we examined the intracellular Ca(2+) handling in myocytes isolated from post-MI hearts resistant (VF-) and susceptible (VF+) to VF. Frequency of occurrence of diastolic Ca(2+) waves (DCWs) in VF+ myocytes from placebo group was significantly higher than in placebo-treated VF- myocytes. n-3 PUFA treatment did not decrease frequency of DCWs in VF+ myocytes. In contrast, VF- myocytes from the n-3 PUFA group had a significantly higher frequency of DCWs than myocytes from the placebo group. In addition, n-3 PUFA treatment increased beat-to-beat alterations in the amplitude of Ca(2+) transients (Ca(2+) alternans) in VF- myocytes. These n-3 PUFAs effects in VF- myocytes were associated with an increased Ca(2+) spark frequency and reduced sarcoplasmic reticulum Ca(2+) content, indicative of increased activity of ryanodine receptors. Thus, dietary n-3 PUFAs do not alleviate intracellular Ca(2+) cycling remodeling in myocytes isolated from post-MI VF+ hearts. Furthermore, dietary n-3 PUFAs increase vulnerability of ventricular myocytes to cellular arrhythmia in post-MI VF- hearts by destabilizing intracellular Ca(2+) handling.
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Affiliation(s)
- Andriy E. Belevych
- Dorothy M. Davis Heart and Lung Research Institute, the Ohio State University, Columbus, Ohio, United States of America
- Department of Physiology and Cell Biology, College of Medicine, the Ohio State University, Columbus, Ohio, United States of America
- * E-mail:
| | - Hsiang-Ting Ho
- Dorothy M. Davis Heart and Lung Research Institute, the Ohio State University, Columbus, Ohio, United States of America
- Department of Physiology and Cell Biology, College of Medicine, the Ohio State University, Columbus, Ohio, United States of America
| | - Radmila Terentyeva
- Dorothy M. Davis Heart and Lung Research Institute, the Ohio State University, Columbus, Ohio, United States of America
- Department of Physiology and Cell Biology, College of Medicine, the Ohio State University, Columbus, Ohio, United States of America
- Department of Medicine, Rhode Island Hospital and the Warren Alpert Medical School of Brown University, Providence, Rhode Island, United States of America
| | - Ingrid M. Bonilla
- College of Pharmacy, the Ohio State University, Columbus, Ohio, United States of America
| | - Dmitry Terentyev
- Dorothy M. Davis Heart and Lung Research Institute, the Ohio State University, Columbus, Ohio, United States of America
- Department of Physiology and Cell Biology, College of Medicine, the Ohio State University, Columbus, Ohio, United States of America
- Department of Medicine, Rhode Island Hospital and the Warren Alpert Medical School of Brown University, Providence, Rhode Island, United States of America
| | - Cynthia A. Carnes
- Dorothy M. Davis Heart and Lung Research Institute, the Ohio State University, Columbus, Ohio, United States of America
- Department of Physiology and Cell Biology, College of Medicine, the Ohio State University, Columbus, Ohio, United States of America
- College of Pharmacy, the Ohio State University, Columbus, Ohio, United States of America
| | - Sandor Gyorke
- Dorothy M. Davis Heart and Lung Research Institute, the Ohio State University, Columbus, Ohio, United States of America
- Department of Physiology and Cell Biology, College of Medicine, the Ohio State University, Columbus, Ohio, United States of America
| | - George E. Billman
- Dorothy M. Davis Heart and Lung Research Institute, the Ohio State University, Columbus, Ohio, United States of America
- Department of Physiology and Cell Biology, College of Medicine, the Ohio State University, Columbus, Ohio, United States of America
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Salmoirago-Blotcher E, Fitchett G, Hovey KM, Schnall E, Thomson C, Andrews CA, Crawford S, O'Sullivan MJ, Post S, Chlebowski RT, Ockene J. Frequency of private spiritual activity and cardiovascular risk in postmenopausal women: the Women's Health Initiative. Ann Epidemiol 2013; 23:239-45. [PMID: 23621989 DOI: 10.1016/j.annepidem.2013.03.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 01/29/2013] [Accepted: 03/01/2013] [Indexed: 10/26/2022]
Abstract
PURPOSE Spirituality has been associated with better cardiac autonomic balance, but its association with cardiovascular risk is not well studied. We examined whether more frequent private spiritual activity was associated with reduced cardiovascular risk in postmenopausal women enrolled in the Women's Health Initiative Observational Study. METHODS Frequency of private spiritual activity (prayer, Bible reading, and meditation) was self-reported at year 5 of follow-up. Cardiovascular outcomes were centrally adjudicated, and cardiovascular risk was estimated from proportional hazards models. RESULTS Final models included 43,708 women (mean age, 68.9 ± 7.3 years; median follow-up, 7.0 years) free of cardiac disease through year 5 of follow-up. In age-adjusted models, private spiritual activity was associated with increased cardiovascular risk (hazard ratio [HR], 1.16; 95% confidence interval [CI], 1.02-1.31 for weekly vs. never; HR, 1.25; 95% CI, 1.11-1.40 for daily vs. never). In multivariate models adjusted for demographics, lifestyle, risk factors, and psychosocial factors, such association remained significant only in the group with daily activity (HR, 1.16; 95% CI, 1.03-1.30). Subgroup analyses indicate this association may be driven by the presence of severe chronic diseases. CONCLUSIONS Among aging women, higher frequency of private spiritual activity was associated with increased cardiovascular risk, likely reflecting a mobilization of spiritual resources to cope with aging and illness.
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Billman GE. The effect of heart rate on the heart rate variability response to autonomic interventions. Front Physiol 2013; 4:222. [PMID: 23986716 PMCID: PMC3752439 DOI: 10.3389/fphys.2013.00222] [Citation(s) in RCA: 118] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Accepted: 08/02/2013] [Indexed: 11/21/2022] Open
Abstract
Heart rate variability (HRV), the beat-to-beat variation in either heart rate (HR) or heart period (R-R interval), has become a popular clinical and investigational tool to quantify cardiac autonomic regulation. However, it is not widely appreciated that, due to the inverse curvilinear relationship between HR and R-R interval, HR per se can profoundly influence HRV. It is, therefore, critical to correct HRV for the prevailing HR particularly, as HR changes in response to autonomic neural activation or inhibition. The present study evaluated the effects of HR on the HRV response to autonomic interventions that either increased (submaximal exercise, n = 25 or baroreceptor reflex activation, n = 20) or reduced (pharmacological blockade: β-adrenergic receptor, muscarinic receptor antagonists alone and in combination, n = 25, or bilateral cervical vagotomy, n = 9) autonomic neural activity in a canine model. Both total (RR interval standard deviation, RRSD) and the high frequency (HF) variability (HF, 0.24–1.04 Hz) were determined before and in response to an autonomic intervention. All interventions that reduced or abolished cardiac parasympathetic regulation provoked large reductions in HRV even after HR correction [division by mean RRsec or (mean RRsec)2 for RRSD and HF, respectively] while interventions that reduced HR yielded mixed results. β-adrenergic receptor blockade reduced HRV (RRSD but not HF) while both RRSD and HF increased in response to increases in arterial blood (baroreceptor reflex activation) even after HR correction. These data suggest that the physiological basis for HRV is revealed after correction for prevailing HR and, further, that cardiac parasympathetic activity is responsible for a major portion of the HRV in the dog.
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Affiliation(s)
- George E Billman
- Department of Physiology and Cell Biology, The Ohio State University Columbus, OH, USA
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