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Olshansky B, Bhatt DL, Miller M, Steg PG, Brinton EA, Jacobson TA, Ketchum SB, Doyle RT, Juliano RA, Jiao L, Kowey PR, Reiffel JA, Tardif J, Ballantyne CM, Chung MK. Cardiovascular Benefits of Icosapent Ethyl in Patients With and Without Atrial Fibrillation in REDUCE-IT. J Am Heart Assoc 2023; 12:e026756. [PMID: 36802845 PMCID: PMC10111466 DOI: 10.1161/jaha.121.026756] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 10/31/2022] [Indexed: 02/23/2023]
Abstract
Background In REDUCE-IT (Reduction of Cardiovascular Events With Icosapent Ethyl-Intervention Trial), icosapent ethyl (IPE) versus placebo) reduced cardiovascular death, myocardial infarction, stroke, coronary revascularization, or unstable angina requiring hospitalization, but was associated with increased atrial fibrillation/atrial flutter (AF) hospitalization (3.1% IPE versus 2.1% placebo; P=0.004). Methods and Results We performed post hoc efficacy and safety analyses of patients with or without prior AF (before randomization) and with or without in-study time-varying AF hospitalization to assess relationships of IPE (versus placebo) and outcomes. In-study AF hospitalization event rates were higher in patients with prior AF (12.5% versus 6.3%, IPE versus placebo; P=0.007) versus without prior AF (2.2% versus 1.6%, IPE versus placebo; P=0.09). Serious bleeding rates trended higher in patients with (7.3% versus 6.0%, IPE versus placebo; P=0.59) versus without prior AF (2.3% versus 1.7%, IPE versus placebo; P=0.08). With IPE, serious bleeding trended higher regardless of prior AF (interaction P value [Pint]=0.61) or postrandomization AF hospitalization (Pint=0.66). Patients with prior AF (n=751, 9.2%) versus without prior AF (n=7428, 90.8%) had similar relative risk reductions of the primary composite and key secondary composite end points with IPE versus placebo (Pint=0.37 and Pint=0.55, respectively). Conclusions In REDUCE-IT, in-study AF hospitalization rates were higher in patients with prior AF especially in those randomized to IPE. Although serious bleeding trended higher in those randomized to IPE versus placebo over the course of the study, serious bleeding was not different regardless of prior AF or in-study AF hospitalization. Patients with prior AF or in-study AF hospitalization had consistent relative risk reductions across primary, key secondary, and stroke end points with IPE. Registration URL: https://clinicaltrials.gov/ct2/show/NCT01492361; Unique Identifier: NCT01492361.
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Affiliation(s)
| | - Deepak L. Bhatt
- Mount Sinai HeartIcahn School of Medicine at Mount Sinai Health SystemNew YorkNYUSA
| | - Michael Miller
- Department of MedicineCrescenz Veterans Affairs Medical Center and Hospital of the University of PennsylvaniaPhiladelphiaPAUSA
| | - Ph. Gabriel Steg
- French Alliance for Cardiovascular Trials, Hôpital BichatParisFrance
- Assistance Publique‐Hôpitaux de ParisUniversité Paris–Cité, INSERM UnitéParisFrance
| | | | - Terry A. Jacobson
- Lipid Clinic and Cardiovascular Risk Reduction Program, Department of MedicineEmory University School of MedicineAtlantaGAUSA
| | | | | | | | | | | | - James A. Reiffel
- Columbia University Vagelos College of Physicians & SurgeonsNew YorkNYUSA
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Chiba O, Shimada N, Yoshio S, Kudo Y, Cho Y, Yotsu-Yamashita M, Konoki K. State-Dependent Inhibition of Voltage-Gated Sodium Channels in Neuroblastoma Neuro-2A Cells by Arachidonic Acid from Halichondria okadai. Chem Res Toxicol 2022; 35:1950-1961. [PMID: 36315108 DOI: 10.1021/acs.chemrestox.2c00062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Voltage-gated sodium channels (Nav) are closely associated with epilepsy, cardiac and skeletal muscle diseases, and neuropathic pain. Several toxic compounds have been isolated from the marine sponge Halichondria okadai; however, toxic substances that modulate Nav are yet to be identified. This study aimed to identify Nav inhibitors from two snake venoms and H. okadai using mouse neuroblastoma Neuro-2A cells (N2A), which primarily express the specific Nav subtype Nav1.7, using whole-cell patch-clamp recordings. We successfully isolated arachidonic acid (AA, 1) from the hexane extract of H. okadai, and then the fatty acid-mediated modulation of Nav in N2A was investigated in detail for the first time. Octanoic acid (2), palmitic acid (3), and oleic acid (4) showed no inhibitory activity at 100 μM, whereas AA (1), dihomo-γ-linolenic acid (DGLA, 5), and eicosapentaenoic acid (EPA, 6) showed IC50 values of 6.1 ± 2.0, 58 ± 19, and 25 ± 4.0 μM, respectively (N = 4, mean ± SEM). Structure and activity relationships were investigated for the first time using two ω-3 polyunsaturated fatty acids (PUFAs), EPA (6) and eicosatetraenoic acid (ETA, 7), and two ω-6 PUFAs, AA (1) and DGLA (5), to determine their effects on a resting state, activated state, and inactivated state. Steady-state analysis showed that the half inactivation potential was largely hyperpolarized by 10 μM AA (1), while 50 μM DGLA (5), 50 μM EPA (6), and 10 μM ETA (7) led to a slight change. The percentages of the resting state block were 24 ± 1, 22 ± 1, 34 ± 4, and 38 ± 9% in the presence of AA (1), DGLA (5), EPA (6), and ETA (7), respectively, with EPA (6) and ETA (7) exhibiting a greater inhibition than both AA (1) and DGLA (5), and their inhibitions did not increase in the following depolarization pulses. None of the compounds exhibited the use-dependent block. The half recovery times from the inactivated state for the control, AA (1), DGLA (5), EPA (6), and ETA (7) were 7.67 ± 0.33, 34.3 ± 1.10, 15.5 ± 1.10, 10.7 ± 0.31, and 3.59 ± 0.18 ms, respectively, with AA (1) exhibiting a distinctively large effect. Overall, distributed binding to the resting and the inactivated states of Nav would be significant for the inhibition of Nav, which presumably depends on the active structure of each PUFA.
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Affiliation(s)
- Osamu Chiba
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
| | - Noriko Shimada
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
| | - Shutaro Yoshio
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
| | - Yuta Kudo
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan.,Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8578, Japan
| | - Yuko Cho
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
| | - Mari Yotsu-Yamashita
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
| | - Keiichi Konoki
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
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3
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Dominic P, Ahmad J, Awwab H, Bhuiyan MS, Kevil CG, Goeders NE, Murnane KS, Patterson JC, Sandau KE, Gopinathannair R, Olshansky B. Stimulant Drugs of Abuse and Cardiac Arrhythmias. Circ Arrhythm Electrophysiol 2022; 15:e010273. [PMID: 34961335 PMCID: PMC8766923 DOI: 10.1161/circep.121.010273] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Nonmedical use of prescription and nonprescription drugs is a worldwide epidemic, rapidly growing in magnitude with deaths because of overdose and chronic use. A vast majority of these drugs are stimulants that have various effects on the cardiovascular system including the cardiac rhythm. Drugs, like cocaine and methamphetamine, have measured effects on the conduction system and through several direct and indirect pathways, utilizing multiple second messenger systems, change the structural and electrical substrate of the heart, thereby promoting cardiac dysrhythmias. Substituted amphetamines and cocaine affect the expression and activation kinetics of multiple ion channels and calcium signaling proteins resulting in EKG changes, and atrial and ventricular brady and tachyarrhythmias. Preexisting conditions cause substrate changes in the heart, which decrease the threshold for such drug-induced cardiac arrhythmias. The treatment of cardiac arrhythmias in patients who take drugs of abuse may be specialized and will require an understanding of the unique underlying mechanisms and necessitates a multidisciplinary approach. The use of primary or secondary prevention defibrillators in drug abusers with chronic systolic heart failure is both sensitive and controversial. This review provides a broad overview of cardiac arrhythmias associated with stimulant substance abuse and their management.
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Affiliation(s)
- Paari Dominic
- Center of Excellence for Cardiovascular Diseases & Sciences, Louisiana State University Health Sciences Center-Shreveport, LA, Department of Medicine, Louisiana State University Health Sciences Center-Shreveport, LA
| | - Javaria Ahmad
- Department of Medicine, Louisiana State University Health Sciences Center-Shreveport, LA
| | - Hajra Awwab
- Center of Excellence for Cardiovascular Diseases & Sciences, Louisiana State University Health Sciences Center-Shreveport, LA, Department of Medicine, Louisiana State University Health Sciences Center-Shreveport, LA
| | - Md. Shenuarin Bhuiyan
- Center of Excellence for Cardiovascular Diseases & Sciences, Louisiana State University Health Sciences Center-Shreveport, LA, Department of Pathology and Translational Pathobiology, Louisiana State University Health Sciences Center, Shreveport, LA, Department of Molecular and Cellular Physiology Louisiana State University Health Sciences Center, Shreveport, LA
| | - Christopher G. Kevil
- Center of Excellence for Cardiovascular Diseases & Sciences, Louisiana State University Health Sciences Center-Shreveport, LA, Department of Pathology and Translational Pathobiology, Louisiana State University Health Sciences Center, Shreveport, LA, Department of Molecular and Cellular Physiology Louisiana State University Health Sciences Center, Shreveport, LA, Department of Cellular Biology and Anatomy Louisiana State University Health Sciences Center, Shreveport, LA
| | - Nicholas E. Goeders
- Department of Pharmacology, Toxicology and Neuroscience, Louisiana State University Health Sciences Center-Shreveport, LA
| | - Kevin S. Murnane
- Department of Pharmacology, Toxicology and Neuroscience, Louisiana State University Health Sciences Center-Shreveport, LA, Department of Psychiatry, Louisiana State University Health Sciences Center, Shreveport, LA
| | - James C. Patterson
- Department of Psychiatry, Louisiana State University Health Sciences Center, Shreveport, LA
| | | | - Rakesh Gopinathannair
- The Kansas City Heart Rhythm Institute (KCHRI) & Research Foundation, Overland Park Regional Medical Center, Overland Park, KS
| | - Brian Olshansky
- University of Iowa Carver College of Medicine, Iowa City, IA
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Soriani O, Kourrich S. The Sigma-1 Receptor: When Adaptive Regulation of Cell Electrical Activity Contributes to Stimulant Addiction and Cancer. Front Neurosci 2019; 13:1186. [PMID: 31780884 PMCID: PMC6861184 DOI: 10.3389/fnins.2019.01186] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 10/21/2019] [Indexed: 12/17/2022] Open
Abstract
The sigma-1 receptor (σ1R) is an endoplasmic reticulum (ER)-resident chaperone protein that acts like an inter-organelle signaling modulator. Among its several functions such as ER lipid metabolisms/transports and indirect regulation of genes transcription, one of its most intriguing feature is the ability to regulate the function and trafficking of a variety of functional proteins. To date, and directly relevant to the present review, σ1R has been found to regulate both voltage-gated ion channels (VGICs) belonging to distinct superfamilies (i.e., sodium, Na+; potassium, K+; and calcium, Ca2+ channels) and non-voltage-gated ion channels. This regulatory function endows σ1R with a powerful capability to fine tune cells’ electrical activity and calcium homeostasis—a regulatory power that appears to favor cell survival in pathological contexts such as stroke or neurodegenerative diseases. In this review, we present the current state of knowledge on σ1R’s role in the regulation of cellular electrical activity, and how this seemingly adaptive function can shift cell homeostasis and contribute to the development of very distinct chronic pathologies such as psychostimulant abuse and tumor cell growth in cancers.
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Affiliation(s)
| | - Saïd Kourrich
- Département des Sciences Biologiques, Université du Québec à Montréal, Montréal, QC, Canada.,Centre d'Excellence en Recherche sur les Maladies Orphelines - Fondation Courtois, Université du Québec à Montréal, Montréal, QC, Canada.,Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, United States.,Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, United States
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5
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Alí A, Boutjdir M, Aromolaran AS. Cardiolipotoxicity, Inflammation, and Arrhythmias: Role for Interleukin-6 Molecular Mechanisms. Front Physiol 2019; 9:1866. [PMID: 30666212 PMCID: PMC6330352 DOI: 10.3389/fphys.2018.01866] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 12/11/2018] [Indexed: 12/12/2022] Open
Abstract
Fatty acid infiltration of the myocardium, acquired in metabolic disorders (obesity, type-2 diabetes, insulin resistance, and hyperglycemia) is critically associated with the development of lipotoxic cardiomyopathy. According to a recent Presidential Advisory from the American Heart Association published in 2017, the current average dietary intake of saturated free-fatty acid (SFFA) in the US is 11–12%, which is significantly above the recommended <10%. Increased levels of circulating SFFAs (or lipotoxicity) may represent an unappreciated link that underlies increased vulnerability to cardiac dysfunction. Thus, an important objective is to identify novel targets that will inform pharmacological and genetic interventions for cardiomyopathies acquired through excessive consumption of diets rich in SFFAs. However, the molecular mechanisms involved are poorly understood. The increasing epidemic of metabolic disorders strongly implies an undeniable and critical need to further investigate SFFA mechanisms. A rapidly emerging and promising target for modulation by lipotoxicity is cytokine secretion and activation of pro-inflammatory signaling pathways. This objective can be advanced through fundamental mechanisms of cardiac electrical remodeling. In this review, we discuss cardiac ion channel modulation by SFFAs. We further highlight the contribution of downstream signaling pathways involving toll-like receptors and pathological increases in pro-inflammatory cytokines. Our expectation is that if we understand pathological remodeling of major cardiac ion channels from a perspective of lipotoxicity and inflammation, we may be able to develop safer and more effective therapies that will be beneficial to patients.
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Affiliation(s)
- Alessandra Alí
- Cardiovascular Research Program, VA New York Harbor Healthcare System, Brooklyn, NY, United States.,Department of Medicine, State University of New York Downstate Medical Center, Brooklyn, NY, United States.,Department of Cell Biology, State University of New York Downstate Medical Center, Brooklyn, NY, United States.,Department of Pharmacology, State University of New York Downstate Medical Center, Brooklyn, NY, United States.,Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Mohamed Boutjdir
- Cardiovascular Research Program, VA New York Harbor Healthcare System, Brooklyn, NY, United States.,Department of Medicine, State University of New York Downstate Medical Center, Brooklyn, NY, United States.,Department of Cell Biology, State University of New York Downstate Medical Center, Brooklyn, NY, United States.,Department of Pharmacology, State University of New York Downstate Medical Center, Brooklyn, NY, United States.,Department of Medicine, New York University School of Medicine, New York, NY, United States
| | - Ademuyiwa S Aromolaran
- Cardiovascular Research Program, VA New York Harbor Healthcare System, Brooklyn, NY, United States.,Department of Medicine, State University of New York Downstate Medical Center, Brooklyn, NY, United States.,Department of Cell Biology, State University of New York Downstate Medical Center, Brooklyn, NY, United States.,Department of Pharmacology, State University of New York Downstate Medical Center, Brooklyn, NY, United States
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6
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Su C, Ying W, Xiangming L, Xinxin P. Inhibitive effect of loureirin B plus capsaicin on tetrodotoxin-resistant sodium channel. J TRADIT CHIN MED 2018. [DOI: 10.1016/s0254-6272(18)30983-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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7
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Elinder F, Liin SI. Actions and Mechanisms of Polyunsaturated Fatty Acids on Voltage-Gated Ion Channels. Front Physiol 2017; 8:43. [PMID: 28220076 PMCID: PMC5292575 DOI: 10.3389/fphys.2017.00043] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 01/16/2017] [Indexed: 01/29/2023] Open
Abstract
Polyunsaturated fatty acids (PUFAs) act on most ion channels, thereby having significant physiological and pharmacological effects. In this review we summarize data from numerous PUFAs on voltage-gated ion channels containing one or several voltage-sensor domains, such as voltage-gated sodium (NaV), potassium (KV), calcium (CaV), and proton (HV) channels, as well as calcium-activated potassium (KCa), and transient receptor potential (TRP) channels. Some effects of fatty acids appear to be channel specific, whereas others seem to be more general. Common features for the fatty acids to act on the ion channels are at least two double bonds in cis geometry and a charged carboxyl group. In total we identify and label five different sites for the PUFAs. PUFA site 1: The intracellular cavity. Binding of PUFA reduces the current, sometimes as a time-dependent block, inducing an apparent inactivation. PUFA site 2: The extracellular entrance to the pore. Binding leads to a block of the channel. PUFA site 3: The intracellular gate. Binding to this site can bend the gate open and increase the current. PUFA site 4: The interface between the extracellular leaflet of the lipid bilayer and the voltage-sensor domain. Binding to this site leads to an opening of the channel via an electrostatic attraction between the negatively charged PUFA and the positively charged voltage sensor. PUFA site 5: The interface between the extracellular leaflet of the lipid bilayer and the pore domain. Binding to this site affects slow inactivation. This mapping of functional PUFA sites can form the basis for physiological and pharmacological modifications of voltage-gated ion channels.
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Affiliation(s)
- Fredrik Elinder
- Department of Clinical and Experimental Medicine, Linköping University Linköping, Sweden
| | - Sara I Liin
- Department of Clinical and Experimental Medicine, Linköping University Linköping, Sweden
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8
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Cardiac physiology and clinical efficacy of dietary fish oil clarified through cellular mechanisms of omega-3 polyunsaturated fatty acids. Eur J Appl Physiol 2014; 114:1333-56. [DOI: 10.1007/s00421-014-2876-z] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 03/20/2014] [Indexed: 01/18/2023]
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9
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Billman GE. The effects of omega-3 polyunsaturated fatty acids on cardiac rhythm: a critical reassessment. Pharmacol Ther 2013; 140:53-80. [PMID: 23735203 DOI: 10.1016/j.pharmthera.2013.05.011] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Accepted: 05/17/2013] [Indexed: 11/28/2022]
Abstract
Although epidemiological studies provide strong evidence for an inverse relationship between omega-3 polyunsaturated fatty acids (n-3 PUFAs) and cardiac mortality, inconsistent and often conflicting results have been obtained from both animal studies and clinical prevention trials. Despite these heterogeneous results, some general conclusions can be drawn from these studies: 1) n-PUFAs have potent effects on ion channels and calcium regulatory proteins that vary depending on the route of administration. Circulating (acute administration) n-3 PUFAs affect ion channels directly while incorporation (long-term supplementation) of these lipids into cell membranes indirectly alter cardiac electrical activity via alteration of membrane properties. 2) n-3 PUFAs reduce baseline HR and increase HRV via alterations in intrinsic pacemaker rate rather than from changes in cardiac autonomic neural regulation. 3) n-3 PUFAs may be only effective if given before electrophysiological or structural remodeling has begun and have no efficacy against atrial fibrillation. 5) Despite initial encouraging results, more recent clinical prevention and animal studies have not only failed to reduce sudden cardiac death but actually increased mortality in angina patients and increased rather than decreased malignant arrhythmias in animal models of regional ischemia. 6) Given the inconsistent benefits reported in clinical and experimental studies and the potential adverse actions on cardiac rhythm noted during myocardial ischemia, n-3 PUFA must be prescribed with caution and generalized recommendations to increase fish intake or to take n-3 PUFA supplements need to be reconsidered.
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Affiliation(s)
- George E Billman
- Department of Physiology and Cell Biology, The Ohio State University, 304 Hamilton Hall, 1645 Neil Ave., Columbus, OH 43210-1218, United States.
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10
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Saini-Chohan HK, Hryshko L, Xu YJ, Dhalla NS. Modification of Ca(2+)-handling in cardiomyocytes by redox sensitive mechanisms in response to ouabain. Can J Physiol Pharmacol 2013; 91:45-55. [PMID: 23367872 DOI: 10.1139/cjpp-2012-0215] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We examined the role of redox-sensitive signal transduction mechanisms in modifying the changes in [Ca(2+)](i) produced by ouabain upon incubating adult rat cardiomyocytes with antioxidants or inhibitors of different protein kinases and monitoring alterations in fura-2 fluorescence. Ouabain increased basal [Ca(2+)](i), augmented the KCl-induced increase in [Ca(2+)](i), and promoted oxyradical production in cardiomyocytes. These actions of ouabain were attenuated by an oxyradical scavenging mixture (superoxide dismutase plus catalase), and the antioxidants (N-acetyl-L-cysteine and N-(2-mercaptoproprionyl)glycine). An inhibitor of MAP kinase (PD98059) depressed the ouabain-induced increase in [Ca(2+)], whereas inhibitors of tyrosine kinase (tyrphostin and genistein) and PI3 kinase (Wortmannin and LV294002) enhanced the ouabain-induced increase in [Ca(2+)](i). Inhibitors of protein kinase C (calphostin and bisindolylmalaimide) augmented the ouabain-induced increase in [Ca(2+)](i), whereas stimulation of protein kinase C by a phorbol ester (phorbol 12-myristate 13-acetate) depressed the action of ouabain. These results suggest that ouabain-induced inhibition of Na (+)-K(+) ATPase may alter the redox status of cardiomyocytes through the production of oxyradicals, and increase the activities of various protein kinases. Thus, these redox-sensitive signal transduction mechanisms involving different protein kinases may modify Ca(2+)-handling sites in cardiomyocytes and determine the magnitude of net increase in [Ca(2+)](i) in response to ouabain.
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Affiliation(s)
- Harjot K Saini-Chohan
- Institute of Cardiovascular Sciences, St. Boniface Hospital Research and Department of Physiology, Faculty of Medicine, University of Manitoba, 351 Tache Avenue, Winnipeg, MB R2H 2A6, Canada
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Li HX, Wang RX, Li XR, Guo T, Wu Y, Guo SX, Sun LP, Yang ZY, Yang XJ, Jiang WP. Increasing DHA and EPA Concentrations Prolong Action Potential Durations and Reduce Transient Outward Potassium Currents in Rat Ventricular Myocytes. Lipids 2010; 46:163-70. [DOI: 10.1007/s11745-010-3503-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2010] [Accepted: 11/12/2010] [Indexed: 10/18/2022]
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12
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Fan XR, Ma JH, Zhang PH, Xing JL. Blocking effect of methylflavonolamine on human Na(V)1.5 channels expressed in Xenopus laevis oocytes and on sodium currents in rabbit ventricular myocytes. Acta Pharmacol Sin 2010; 31:297-306. [PMID: 20173760 DOI: 10.1038/aps.2010.8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
AIM To investigate the blocking effects of methylflavonolamine (MFA) on human Na(V)1.5 channels expressed in Xenopus laevis oocytes and on sodium currents (I(Na)) in rabbit ventricular myocytes. METHODS Human Na(V)1.5 channels were expressed in Xenopus oocytes and studied using the two-electrode voltage-clamp technique. I(Na) and action potentials in rabbit ventricular myocytes were studied using the whole-cell recording. RESULTS MFA and lidocaine inhibited human Na(V)1.5 channels expressed in Xenopus oocytes in a positive rate-dependent and concentration-dependent manner, with IC(50) values of 72.61 micromol/L and 145.62 micromol/L, respectively. Both of them markedly shifted the steady-state activation curve of I(Na) toward more positive potentials, shifted the steady-state inactivation curve of I(Na) toward more negative potentials and postponed the recovery of the I(Na) inactivation state. In rabbit ventricular myocytes, MFA inhibited I(Na) with a shift in the steady-state inactivation curve toward more negative potentials, thereby postponing the recovery of the I(Na) inactivation state. This shift was in a positive rate-dependent manner. Under current-clamp mode, MAF significantly decreased action potential amplitude (APA) and maximal depolarization velocity (V(max)) and shortened action potential duration (APD), but did not alter the resting membrane potential (RMP). The demonstrated that the kinetics of sodium channel blockage by MFA resemble those of class I antiarrhythmic agents such as lidocaine. CONCLUSION MFA protects the heart against arrhythmias by its blocking effect on sodium channels.
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Effect of Newly Synthesized Compounds 44Bu and 444 on QRS-Complex Width and Fast Sodium Current: Differences between Isomers. ACTA VET BRNO 2010. [DOI: 10.2754/avb201079010041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Two newly synthesized short-acting agents 44Bu and 444 were observed to suppress the aconitine-induced arrhythmias and block the fast sodium currentINain the rat heart. No data about their effect on the electrocardiographic parameters are available. In this study, we explored the effect of both racemates and particular isomers of 44Bu and 444 on the QRS-complex widthin vivoin rats and onINain isolated rat ventricular myocytes. All variants of 44Bu and 444 (1.5 mg/kg) caused a significant QRS-widening reaching the peak effect at the 1st or 2nd min after their intravenous administration. 44Bu racemate widened the QRS-complex from 16.8 ± 0.4 to 26.3 ± 0.5 ms (by 57%), significantly more than R- (33%-widening) and S-isomer (36%-widening). 444 racemate widened the QRS-complex from 20.8 ± 1.0 to 34.1 ± 0.9 ms (by 64%), which was comparable to S-isomer (63%-widening), however, substantially more than R-isomer (40%-widening). Regarding the effect onINa, 44Bu caused a significantly deeperINa- block compared to 444 when applied at the same concentration of 3 μmol/l (~0.1 mg/kg). 44Bu racemate and R-isomer blockedINasimilarly (91.7 ± 0.8 and 91.8 ± 1.6%-block, respectively) and significantly more than S-isomer (82.4 ± 2.3%-block). 444 R-isomer blockedINaless than racemate and S-isomer (by 31.7 ± 3.9% vs. 48.3 ± 4.7 and 50.2 ± 4.1%, respectively). We conclude that both racemates and particular isomers of 44Bu and 444 induce a QRS-widening and blockINain the rat heart, however, their effects notably differed. The relative widening of the QRS-complex after application of 44Bu did not conform to the level ofINa-block observed in isolated cardiomyocytes which stresses the importance ofin vivoexperiments in the pre-clinical testing of new drugs.
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15
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Sanchez-Bustamante CD, Frey U, Kelm JM, Hierlemann A, Fussenegger M. Modulation of cardiomyocyte electrical properties using regulated bone morphogenetic protein-2 expression. Tissue Eng Part A 2009; 14:1969-88. [PMID: 18673087 DOI: 10.1089/ten.tea.2007.0302] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Because cardiomyocytes lose their ability to divide after birth, any subsequent cell loss or dysfunction results in pathologic cardiac rhythm initiation or impulse conduction. Strategies to restore and control the electrophysiological activity of the heart may, therefore, greatly affect the regeneration of cardiac tissue functionality. Using lentivirus-derived particles to regulate the bone morphogenetic protein-2 (BMP-2) gene expression in a pristinamycin- or gaseous acetaldehyde-inducible manner, we demonstrated the adjustment of cardiomyocyte electrophysiological characteristics. Complementary metal oxide semiconductor-based high-density microelectrode arrays (HD-MEAs) were used to monitor the electrophysiological activity of neonatal rat cardiomyocytes (NRCs) cultured as monolayers (NRCml) or as microtissues (NRCmt). NRCmt more closely resembled heart tissue physiology than did NRCml and could be conveniently monitored using HD-MEAs because of their ability to detect low-signal events and to sub-select the region of interest, namely, areas where the microtissues were placed. Cardiomyocyte-forming microtissues, transduced using lentiviral vectors encoding BMP-2, were capable of restoring myocardial microtissue electrical activity. We also engineered NRCmt to functionally couple within a cardiomyocyte monolayer, thus showing pacemaker-like activity upon local regulation of transgenic BMP-2 expression. The controlled expression of therapeutic transgenes represents a crucial advance for clinical interventions and gene-function analysis.
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Yu M, Chen L. Modulation of major voltage- and ligand-gated ion channels in cultured neurons of the rat inferior colliculus by lidocaine. Acta Pharmacol Sin 2008; 29:1409-18. [PMID: 19026159 DOI: 10.1111/j.1745-7254.2008.00893.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
AIM The purpose of the present study was to explore how lidocaine as a therapeutic drug for tinnitus targets voltage- and ligand-gated ion channels and changes the excitability of central auditory neurons. METHODS Membrane currents mediated by major voltage- and ligand-gated channels were recorded from primary cultured neurons of the inferior colliculus (IC) in rats with whole-cell patch-clamp techniques in the presence and absence of lidocaine. The effects of lidocaine on the current-evoked firing of action potentials were also examined. RESULTS Lidocaine at 100 micromol/L significantly suppressed voltage-gated sodium currents, transient outward potassium currents, and the glycine-induced chloride currents to 87.66%+/-2.12%, 96.33%+/-0.35%, and 91.46%+/-2.69% of that of the control level, respectively. At 1 mmol/L, lidocaine further suppressed the 3 currents to 70.26%+/-4.69%, 62.80%+/-2.61%, and 89.11%+/-3.17% of that of the control level, respectively. However, lidocaine at concentrations lower than 1 mmol/L did not significantly affect GABA- or aspartate-induced currents. At a higher concentration (3 mmol/L), lidocaine slightly depressed the GABA-induced current to 87.70%+/-1.87% of that of the control level. Finally, lidocaine at 100 mumol/L was shown to significantly suppress the current-evoked firing of IC neurons to 58.62%+/-11.22% of that of the control level, indicating that lidocaine decreases neuronal excitability. CONCLUSION Although the action of lidocaine on the ion channels and receptors is complex and non-specific, it has an overall inhibitory effect on IC neurons at a clinically-relevant concentration, suggesting a central mechanism for lidocaine to suppress tinnitus.
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Affiliation(s)
- Mu Yu
- Auditory Research Laboratory, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
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Olgar S, Ertugrul T, Nisli K, Omeroglu RE, Dindar A, Aydogan U. Fish Oil Supplementation Improves Left Ventricular Function in Children With Idiopathic Dilated Cardiomyopathy. ACTA ACUST UNITED AC 2007; 13:308-12. [DOI: 10.1111/j.1527-5299.2007.07135.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Saini HK, Dhalla NS. Sarcolemmal cation channels and exchangers modify the increase in intracellular calcium in cardiomyocytes on inhibiting Na+-K+-ATPase. Am J Physiol Heart Circ Physiol 2007; 293:H169-81. [PMID: 17322410 DOI: 10.1152/ajpheart.00007.2007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Although inhibition of the sarcolemmal (SL) Na+-K+-ATPase is known to cause an increase in the intracellular concentration of Ca2+([Ca2+]i) by stimulating the SL Na+/Ca2+exchanger (NCX), the involvement of other SL sites in inducing this increase in [Ca2+]iis not fully understood. Isolated rat cardiomyocytes were treated with or without different agents that modify Ca2+movements by affecting various SL sites and were then exposed to ouabain. Ouabain was observed to increase the basal levels of both [Ca2+]iand intracellular Na+concentration ([Na+]i) as well as to augment the KCl-induced increases in both [Ca2+]iand [Na+]iin a concentration-dependent manner. The ouabain-induced changes in [Na+]iand [Ca2+]iwere attenuated by treatment with inhibitors of SL Na+/H+exchanger and SL Na+channels. Both the ouabain-induced increase in basal [Ca2+]iand augmentation of the KCl response were markedly decreased when cardiomyocytes were exposed to 0–10 mM Na+. Inhibitors of SL NCX depressed but decreasing extracellular Na+from 105–35 mM augmented the ouabain-induced increase in basal [Ca2+]iand the KCl response. Not only was the increase in [Ca2+]iby ouabain dependent on the extracellular Ca2+concentration, but it was also attenuated by inhibitors of SL L-type Ca2+channels and store-operated Ca2+channels (SOC). Unlike the SL L-type Ca2+-channel blocker, the blockers of SL Na+channel and SL SOC, when used in combination with SL NCX inhibitor, showed additive effects in reducing the ouabain-induced increase in basal [Ca2+]i. These results support the view that in addition to SL NCX, SL L-type Ca2+channels and SL SOC may be involved in raising [Ca2+]ion inhibition of the SL Na+-K+-ATPase by ouabain. Furthermore, both SL Na+/H+exchanger and Na+channels play a critical role in the ouabain-induced Ca2+increase in cardiomyocytes.
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Affiliation(s)
- Harjot K Saini
- Institute of Cardiovascular Sciences, St. Boniface General Hospital Research Centre, 351 Tache Avenue, Winnipeg, Manitoba, Canada
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Cao X, Cao X, Xie H, Yang R, Lei G, Li F, Li A, Liu C, Liu L. Effects of capsaicin on VGSCs in TRPV1-/- mice. Brain Res 2007; 1163:33-43. [PMID: 17632091 DOI: 10.1016/j.brainres.2007.04.085] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2007] [Revised: 04/26/2007] [Accepted: 04/30/2007] [Indexed: 12/20/2022]
Abstract
Two different mechanisms by which capsaicin blocks voltage-gated sodium channels (VGSCs) were found by using knockout mice for the transient receptor potential V1 (TRPV1(-/-)). Similar with cultured rat trigeminal ganglion (TG) neurons, the amplitude of tetrodotoxin-resistant (TTX-R) sodium current was reduced 85% by 1 muM capsaicin in capsaicin sensitive neurons, while only 6% was blocked in capsaicin insensitive neurons of TRPV1(+/+) mice. The selective effect of low concentration capsaicin on VGSCs was reversed in TRPV1(-/-) mice, which suggested that this effect was dependent on TRPV1 receptor. The blockage effect of high concentration capsaicin on VGSCs in TRPV1(-/-) mice was the same as that in capsaicin insensitive neurons of rats and TRPV1(+/+) mice. It is noted that non-selective effect of capsaicin on VGSCs shares many similarities with local anesthetics. That is, firstly, both blockages are concentration-dependent and revisable. Secondly, being accompanied with the reduction of amplitude, voltage-dependent inactivation curve shifts to hyperpolarizing direction without a shift of activation curve. Thirdly, use-dependent blocks are induced at high stimulus frequency.
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Affiliation(s)
- Xuehong Cao
- Department of Physiology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
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Abstract
Fish oil, and omega-3 fatty acids in particular, have been found to reduce plasma levels of triglycerides and increase levels of high-density lipoprotein in patients with marked hypertriglyceridemia, and a pharmaceutical-grade preparation has recently received approval from the US Food and Drug Administration to market for this purpose. However, in both bench research studies and clinical trials, evidence for clinically significant antiarrhythmic properties has also been detected in association with omega-3 fatty acid intake. Arguably the most significant finding in this data set was the reduction in the incidence of sudden death in survivors of myocardial infarction in the Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico (GISSI)-Prevenzione trial and the subsequent recommendation for administration of fish oil as part of the postinfarction regimen in Europe. This article reviews in detail the basic and clinical research studies of fish oil as an antiarrhythmic entity, the forms of preparation and/or administration that appear to possess these properties and those that do not, the types of arrhythmias (ventricular ectopy and atrial fibrillation as well as ventricular tachyarrhythmias) that have been beneficially affected by fish oil administration, and the presumed and known mechanisms by which the beneficial actions are exerted.
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MESH Headings
- Animals
- Anti-Arrhythmia Agents/pharmacology
- Anti-Arrhythmia Agents/therapeutic use
- Arrhythmias, Cardiac/complications
- Arrhythmias, Cardiac/etiology
- Arrhythmias, Cardiac/prevention & control
- Clinical Trials as Topic
- Death, Sudden, Cardiac/epidemiology
- Death, Sudden, Cardiac/etiology
- Death, Sudden, Cardiac/prevention & control
- Defibrillators, Implantable
- Fatty Acids, Omega-3/pharmacology
- Fatty Acids, Omega-3/therapeutic use
- Fish Oils/administration & dosage
- Fish Oils/pharmacology
- Humans
- Hypertriglyceridemia/complications
- Hypertriglyceridemia/diet therapy
- Hypertriglyceridemia/drug therapy
- Italy/epidemiology
- Multicenter Studies as Topic
- Myocardial Infarction/complications
- Water-Electrolyte Balance/drug effects
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Affiliation(s)
- James A Reiffel
- Division of Cardiology, Department of Medicine, College of Physicians and Surgeons, Columbia University Medical Center, New York, New York 10032, USA.
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Ma YL, Peters NS, Henry JA. α1-Acid glycoprotein reverses cocaine-induced sodium channel blockade in cardiac myocytes. Toxicology 2006; 220:46-50. [PMID: 16406254 DOI: 10.1016/j.tox.2005.11.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2005] [Revised: 11/23/2005] [Accepted: 11/23/2005] [Indexed: 11/23/2022]
Abstract
UNLABELLED Alpha 1-acid glycoprotein (AAG) is an acute phase protein capable of binding basic drugs. This action explains its reversal of sodium channel blockade by drugs such as amitriptyline and quinidine. We report here the reversal of cocaine-induced sodium channel blockade by AAG. The sodium channel blocking property of cocaine is a major mechanism behind cocaine-induced sudden cardiac death, since sodium channels play a key role in the initiation and regulation of the heart beat. Voltage-gated sodium current (I(Na)) was recorded using whole-cell patch-clamp techniques. Guinea-pig cardiac ventricular myocytes were isolated and continuously perfused at room temperature with physiological solutions. At concentrations ranging from 5 to 320 microM cocaine showed a dose-dependent and reversible blockade of I(Na) with an IC50 of 45.9 microM. The addition of equimolar amounts of AAG to cocaine produced almost complete reversal of cocaine's effects, suggesting a single binding site for cocaine on the AAG molecule. With changes of peak I(Na) normalized against control as 1, cocaine at 20 and 40 microM reduced I(Na) to 0.62+/-0.042 (n = 6) and 0.57+/-0.052 (n = 9), respectively, and the addition of an equimolar concentration of AAG reversed I(Na) to 0.86+/-0.022 and 0.91+/-0.060, respectively. IN CONCLUSION AAG reverses cocaine-induced sodium channel blockade in a dose-dependent manner, indicating a therapeutic potential to reverse acute cocaine cardiac toxicity.
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Affiliation(s)
- Yu-Ling Ma
- Department of Cardiac Electrophysiology, National Heart and Lung Institute, Imperial College London, 10th Floor QEQM Wing, St. Mary's Hospital, London W21NY, UK.
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Xiao YF, Sigg DC, Leaf A. The Antiarrhythmic Effect of n-3 Polyunsaturated Fatty Acids: Modulation of Cardiac Ion Channels as a Potential Mechanism. J Membr Biol 2005; 206:141-54. [PMID: 16456724 DOI: 10.1007/s00232-005-0786-z] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2005] [Indexed: 10/25/2022]
Abstract
Sudden cardiac death remains one of the most serious medical challenges in Western countries. Increasing evidence in recent years has demonstrated that the n-3 polyunsaturated fatty acids (PUFAs) can prevent fatal ventricular arrhythmias in experimental animals and probably in humans. Dietary supplement of fish oils or intravenous infusion of the n-3 PUFAs prevents ventricular fibrillation caused by ischemia/reperfusion. Similar antiarrhythmic effects of these fatty acids are also observed in cultured mammalian cardiomyocytes. Based on clinical observations and experimental studies in vitro and in vivo, several mechanisms have been postulated for the antiarrhythmic effect of the n-3 PUFAs. The data from our laboratory and others have shown that the n-3 PUFAs are able to affect the activities of cardiac ion channels. The modulation of channel activities, especially voltage-gated Na(+) and L-type Ca(2+) channels, by the n-3 fatty acids may explain, at least partially, the antiarrhythmic action. It is not clear, however, whether one or more than one mechanism involves the beneficial effect of the n-3 PUFAs on the heart. This article summarizes our recent studies on the specific effects of the n-3 PUFAs on cardiac ion channels. In addition, the effect of the n-3 PUFAs on the human hyperpolarization-activated cyclic-nucleotide-modulated channel is presented.
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Affiliation(s)
- Y-F Xiao
- Cardiac Rhythm Management, Medtronic Inc., Minneapolis, MN 55432, USA.
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Frost L, Vestergaard P. n-3 Fatty acids consumed from fish and risk of atrial fibrillation or flutter: the Danish Diet, Cancer, and Health Study. Am J Clin Nutr 2005; 81:50-4. [PMID: 15640459 DOI: 10.1093/ajcn/81.1.50] [Citation(s) in RCA: 139] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Experimental studies have shown that n-3 polyunsaturated fatty acids in fish may have antiarrhythmic properties. OBJECTIVE We examined the association between consumption of n-3 fatty acids from fish and risk of atrial fibrillation or flutter. DESIGN In a prospective cohort study of 47 949 participants (mean age: 56 y) in the Danish Diet, Cancer, and Health Study, we investigated the relation between the consumption of n-3 fatty acids from fish estimated from a detailed semiquantitative food questionnaire and risk of atrial fibrillation or flutter. The subjects were followed up in the Danish National Registry of Patients for the occurrence of atrial fibrillation or flutter and in the Danish Civil Registration System (vital status and emigration). The consumption of n-3 fatty acids from fish was analyzed as sex-specific quintiles with the use of Cox proportional hazards models. RESULTS During follow-up (x: 5.7 y), atrial fibrillation or flutter had developed in 556 subjects (374 men and 182 women). When the lowest quintile of n-3 fatty acids consumed from fish was used as a reference, the unadjusted hazard rate ratios in quintiles 2, 3, 4, and 5 were 0.93, 1.11, 1.10, and 1.44, respectively (P for trend = 0.001). The corresponding adjusted hazard rate ratios were 0.86, 1.08, 1.01, and 1.34 (P for trend = 0.006). Inclusion of information on the frequency of fatty fish consumption did not alter these associations. CONCLUSIONS Consumption of n-3 fatty acids from fish was not associated with a reduction in risk of atrial fibrillation or flutter. We cannot exclude the possibility of residual confounding caused by a lack of information on intake of fish-oil tablets.
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Affiliation(s)
- Lars Frost
- Department of Cardiology and the Department of Endocrinology and Metabolism, Aarhus Amtssygehus, Aarhus University Hospital, Aarhus, Denmark.
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