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Nasciutti PR, Moraes AT, Santos TK, Gonçalves Queiroz KK, Costa APA, Amaral AR, Fernando Gomes Olivindo R, Pontieri CFF, Jeremias JT, Vendramini THA, Brunetto MA, Carvalho RDOA. Protective effects of omega-3 fatty acids in dogs with myxomatous mitral valve disease stages B2 and C. PLoS One 2021; 16:e0254887. [PMID: 34265016 PMCID: PMC8282066 DOI: 10.1371/journal.pone.0254887] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 07/07/2021] [Indexed: 12/02/2022] Open
Abstract
Myxomatous mitral valve disease (MMVD) is characterized by thickening of the valve leaflets and omega-3 (ω-3) supplementation has been associated with modulation of blood pressure (BP) and heart rate, improvement of doppler echocardiographic indices, antiarrhythmic, anti-inflammatory and anti-dislipidemic effects in dogs and humans, although prospective studies of it single use are still absent in the veterinary literature. The objective of this study was to evaluate the influence of ω-3 supplementation in dogs with MMVD. Twenty-nine dogs were followed quarterly for 12 months by clinical evaluation, arterial blood pressure, electrocardiography, doppler echocardiography, thoracic radiography and laboratory tests including inflammatory mediators and cardiac biomarker blood concentrations. The dogs were classified in stages B2 and C, according to the classification proposed by ACVIM 2019. They were randomly assigned to either ω-3 group (ω-3G) or control group (CG). The ingestion of ω-3 reduced the chance of developing arrhythmias by 2.96 times (p = 0.003). The vertebral heart size (VHS) measurements were higher in the control group (p = 0.033). In conclusion, at the dosages used in this study, ω-3 dietary supplementation reduces the volumetric overload, has antiarrhythmic effect and keeps dogs with B2 and C stages of MMVD in milder stages of the disease.
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Affiliation(s)
- Priscilla Regina Nasciutti
- Veterinary Cardiology Service of the Veterinary Hospital of the School of Veterinary Medicine and Animal Science, Federal University of Goias, Goiania, Brazil
| | - Aline Tavares Moraes
- Veterinary Cardiology Service of the Veterinary Hospital of the School of Veterinary Medicine and Animal Science, Federal University of Goias, Goiania, Brazil
| | - Thaiz Krawczyk Santos
- Veterinary Cardiology Service of the Veterinary Hospital of the School of Veterinary Medicine and Animal Science, Federal University of Goias, Goiania, Brazil
| | - Karine Kelly Gonçalves Queiroz
- Veterinary Cardiology Service of the Veterinary Hospital of the School of Veterinary Medicine and Animal Science, Federal University of Goias, Goiania, Brazil
| | - Ana Paula Araújo Costa
- Veterinary Cardiology Service of the Veterinary Hospital of the School of Veterinary Medicine and Animal Science, Federal University of Goias, Goiania, Brazil
| | - Andressa Rodrigues Amaral
- Nutrition and Production Department, Pet Nutrology Research Center, School of Veterinary Medicine and Animal Science, University of Sao Paulo (USP), Pirassununga, Brazil
| | - Rodrigo Fernando Gomes Olivindo
- Nutrition and Production Department, Pet Nutrology Research Center, School of Veterinary Medicine and Animal Science, University of Sao Paulo (USP), Pirassununga, Brazil
| | | | - Juliana Toloi Jeremias
- Nutritional Development Center, Grandfood Indústria e Comércio Ltda (Premier Pet), Dourado, Brazil
| | - Thiago Henrique Annibale Vendramini
- Nutrition and Production Department, Pet Nutrology Research Center, School of Veterinary Medicine and Animal Science, University of Sao Paulo (USP), Pirassununga, Brazil
| | - Marcio Antonio Brunetto
- Nutrition and Production Department, Pet Nutrology Research Center, School of Veterinary Medicine and Animal Science, University of Sao Paulo (USP), Pirassununga, Brazil
| | - Rosângela de Oliveira Alves Carvalho
- Veterinary Cardiology Service of the Veterinary Hospital of the School of Veterinary Medicine and Animal Science, Federal University of Goias, Goiania, Brazil
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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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3
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Janssen PML, Elnakish MT. Modeling heart failure in animal models for novel drug discovery and development. Expert Opin Drug Discov 2019; 14:355-363. [PMID: 30861352 DOI: 10.1080/17460441.2019.1582636] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
INTRODUCTION When investigating drugs that treat heart diseases, it is critical when choosing an animal model for the said model to produce data that is translatable to the human patient population, while keeping in mind the principles of reduction, refinement, and replacement of the animal model in the research. Areas covered: In this review, the authors focus on mammalian models developed to study the impact of drug treatments on human heart failure. Furthermore, the authors address human patient variability and animal model invariability as well as the considerations that need to be made regarding choice of species. Finally, the authors discuss some of the most common models for the two most prominent human heart failure etiologies; increased load on the heart and myocardial ischemia. Expert opinion: In the authors' opinion, the data generated by drug studies is often heavily impacted by the choice of species and the physiologically relevant conditions under which the data are collected. Approaches that use multiple models and are not restricted to small rodents but involve some verification on larger mammals or on human myocardium, are needed to advance drug discovery for the very large patient population that suffers from heart failure.
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Affiliation(s)
- Paul M L Janssen
- a Department of Physiology and Cell Biology , The Ohio State University Wexner Medical Center , Columbus, OH, USA.,b Dorothy M. Davis Heart and Lung Research Institute , The Ohio State University Wexner Medical Center , Columbus, OH, USA.,c Department of Internal Medicine , The Ohio State University Wexner Medical Center , Columbus, OH, USA
| | - Mohammad T Elnakish
- a Department of Physiology and Cell Biology , The Ohio State University Wexner Medical Center , Columbus, OH, USA.,b Dorothy M. Davis Heart and Lung Research Institute , The Ohio State University Wexner Medical Center , Columbus, OH, USA
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4
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Monasky MM, Torres CAA, Janssen PML. Length-Dependent Prolongation of Force Relaxation Is Unaltered by Delay of Intracellular Calcium Decline in Early-Stage Rabbit Right Ventricular Hypertrophy. Front Physiol 2017; 8:945. [PMID: 29255420 PMCID: PMC5723014 DOI: 10.3389/fphys.2017.00945] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 11/08/2017] [Indexed: 11/13/2022] Open
Abstract
Chronic pressure overload can result in ventricular hypertrophy and eventually diastolic dysfunction. In normal myocardium, the time from peak tension to 50% relaxation of isolated cardiac myocardium is not directly determined by the time for calcium decline. This study aims to determine whether the time for calcium decline is altered with a change in preload in early-stage hypertrophied myocardium, and whether this change in time for calcium decline alters the rate of relaxation of the myocardium. Young New Zealand white rabbits underwent a pulmonary artery banding procedure and were euthanized 10 weeks later. Twitch contractions and calibrated bis-fura-2 calcium transients were measured in isolated thin right ventricular trabeculae at optimal length and with the muscle taut. Systolic calcium, calcium transient amplitude, and time from peak tension to 50% relaxation all increased with an increase in preload for both hypertrophied and sham groups. Time for intracellular calcium decline increased both with an increase in preload and an increase in extracellular calcium concentration in hypertrophied myocardium but not in sham, while time from peak tension to 50% relaxation did not significantly change between groups under either condition. Also, time for intracellular calcium decline generally decreased with an increase in extracellular calcium for both hypertrophied and sham groups, while time from peak tension to 50% relaxation generally did not significantly change in either group. Combined, these results indicate that the mild hypertrophy significantly changes calcium handling, but does not impact on the rate of force relaxation. This implies that the rate-limiting step in force relaxation is not directly related to calcium transient decline.
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Affiliation(s)
- Michelle M Monasky
- Department of Physiology and Cell Biology, College of Medicine, Ohio State University, Columbus, OH, United States
| | - Carlos A A Torres
- Department of Physiology and Cell Biology, College of Medicine, Ohio State University, Columbus, OH, United States.,Department of Emergency Medicine, Ohio State University, Columbus, OH, United States
| | - Paul M L Janssen
- Department of Physiology and Cell Biology, College of Medicine, Ohio State University, Columbus, OH, United States
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5
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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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6
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Mączewski M, Duda M, Marciszek M, Kołodziejczyk J, Dobrzyń P, Dobrzyń A, Mackiewicz U. Omega-3 Fatty Acids Do Not Protect Against Arrhythmias in Acute Nonreperfused Myocardial Infarction Despite Some Antiarrhythmic Effects. J Cell Biochem 2016; 117:2570-82. [PMID: 27019087 DOI: 10.1002/jcb.25550] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 03/23/2016] [Indexed: 01/06/2023]
Abstract
Ventricular arrhythmias are an important cause of mortality in the acute myocardial infarction (MI). To elucidate the effect of the omega-3 polyunsaturated fatty acids (PUFAs) on ventricular arrhythmias in acute nonreperfused MI, rats were fed with normal or eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA)-enriched diet for 3 weeks. Subsequently the rats were subjected to either MI induction or sham operation. ECG was recorded for 6 h after the operation and episodes of ventricular tachycardia/fibrillation (VT/VF) were identified. Six hours after MI epicardial monophasic action potentials (MAPs) were recorded, cardiomyocyte Ca(2+) handling was assessed and expression of proteins involved in Ca(2+) turnover was studied separately in non-infarcted left ventricle wall and infarct borderzone. EPA and DHA had no effect on occurrence of post-MI ventricular arrhythmias or mortality. Nevertheless, DHA but not EPA prevented Ca(2+) overload in LV cardiomiocytes and improved rate of Ca(2+) transient decay, protecting PMCA and SERCA function. Moreover, both EPA and DHA prevented MI-induced hyperphosphorylation of ryanodine receptors (RyRs) as well as dispersion of action potential duration (APD) in the left ventricular wall. In conclusion, EPA and DHA have no antiarrhythmic effect in the non-reperfused myocardial infarction in the rat, although these omega-3 PUFAs and DHA in particular exhibit several potential antiarrhythmic effects at the subcellular and tissue level, that is, prevent MI-induced abnormalities in Ca(2+) handling and APD dispersion. In this context further studies are needed to see if these potential antiarrhythmic effects could be utilized in the clinical setting. J. Cell. Biochem. 117: 2570-2582, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Michał Mączewski
- Department of Clinical Physiology, Centre of Postgraduate Medical Education, Warsaw, Poland
| | - Monika Duda
- Department of Clinical Physiology, Centre of Postgraduate Medical Education, Warsaw, Poland
| | - Mariusz Marciszek
- Department of Clinical Physiology, Centre of Postgraduate Medical Education, Warsaw, Poland
| | - Joanna Kołodziejczyk
- Department of Clinical Physiology, Centre of Postgraduate Medical Education, Warsaw, Poland
| | - Paweł Dobrzyń
- Laboratory of Molecular and Medical Biochemistry, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Agnieszka Dobrzyń
- Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Urszula Mackiewicz
- Department of Clinical Physiology, Centre of Postgraduate Medical Education, Warsaw, Poland.
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7
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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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8
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Xu J, Bourgeois H, Vandermeulen E, Vlaeminck B, Meyer E, Demeyere K, Hesta M. Secreted phospholipase A2 inhibitor modulates fatty acid composition and reduces obesity-induced inflammation in Beagle dogs. Vet J 2015; 204:214-9. [PMID: 25920769 DOI: 10.1016/j.tvjl.2015.03.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 03/02/2015] [Accepted: 03/03/2015] [Indexed: 02/07/2023]
Abstract
Secreted phospholipase A2 inhibitor (sPLA2i) has been reported to have an anti-inflammatory function by blocking the production of inflammatory mediators. Obesity is characterized by low-grade inflammation and oxidative stress. The aim of this study was to investigate the effects of dietary supplementation of sPLA2i on inflammation, oxidative stress and serum fatty acid profile in dogs. Seven obese and seven lean Beagle dogs were used in a 28-day double blind cross-over design. Dogs were fed a control diet without supplemental sPLA2i or an sPLA2i supplemented diet. The sPLA2i diet decreased plasma fibrinogen levels and increased the protein:fibrinogen ratio in obese dogs to levels similar to those of lean dogs fed the same diet. Obese dogs had a higher plasma concentration of the lipophilic vitamin A with potential antioxidative capacity and a lower ratio of retinol binding protein 4:vitamin A compared to lean dogs, independent of the diets. A higher proportion of myristic acid (C14:0) and a lower proportion of linoleic acid (C18:2n-6) were observed in the dogs fed with the sPLA2i diet compared to dogs fed with the control diet. Furthermore, a higher ratio of n-6 to n-3, a lower proportion of n-3 polyunsaturated fatty acids and lower omega-3 index were observed in obese compared to lean dogs. The results indicate that obese dogs are characterized by a more 'proinflammatory' serum fatty acid profile and that diet inclusion of sPLA2i may reduce inflammation and alter fatty acid profile.
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Affiliation(s)
- J Xu
- Department of Nutrition, Genetics and Ethology, Faculty of Veterinary Medicine, Ghent University, Heidestraat 19, 9820 Merelbeke, Belgium
| | - H Bourgeois
- Diana Pet Food, ZA du Gohélis, 56250 Elven, France
| | - E Vandermeulen
- Department of Veterinary Medical Imaging and Small Animal Orthopaedics, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - B Vlaeminck
- Department of Animal Production, Faculty of Bioscience Engineering, Ghent University, Proefhoevestraat 10, 9090 Melle, Belgium
| | - E Meyer
- Department of Pharmacology, Biochemistry and Toxicology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - K Demeyere
- Department of Pharmacology, Biochemistry and Toxicology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - M Hesta
- Department of Nutrition, Genetics and Ethology, Faculty of Veterinary Medicine, Ghent University, Heidestraat 19, 9820 Merelbeke, Belgium.
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von Schacky C. Omega-3 fatty acids in cardiovascular disease--an uphill battle. Prostaglandins Leukot Essent Fatty Acids 2015; 92:41-7. [PMID: 24935800 DOI: 10.1016/j.plefa.2014.05.004] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 02/13/2014] [Accepted: 05/06/2014] [Indexed: 12/12/2022]
Abstract
In cardiology, results of recent large intervention trials with eicosapentaenoic acid (EPA) plus docosahexaenoic acid (DHA) supplements were neutral. In contrast, in epidemiologic studies, an inverse relation between clinical events and intake of EPA+DHA was found which was steeper for higher levels of EPA+DHA. A standardized way of determining levels is the Omega-3 Index, which is the percentage of EPA+DHA of a total of 26 fatty acids measured in erythrocytes. According to current criteria, a low Omega-3 Index is a cardiovascular risk factor. What can explain this contradiction? Trial participants were recruited irrespective of their baseline status in EPA+DHA - an important predictor of events. Levels of EPA+DHA have a statistically normal distribution; together with the large inter-individual variability of levels' responding to increased intake, this created a large overlap of EPA+DHA levels between intervention and control groups. Moreover, trial participants were advised to take EPA+DHA supplements with breakfast, frequently a low fat meal, resulting in poor bioavailability. As a result, there is an urgent need for new intervention trials in cardiology, for which participants with a low baseline omega-3 index are recruited, and then treated with individually tailored doses of EPA+DHA to a prespecified target range.
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Affiliation(s)
- Clemens von Schacky
- Medizinische Klinik I, Department Preventive Cardiology, Ludwig-Maximilians-University, Ziemssenstrasse 1, D-80336 Munich, Germany; Omegametrix, Am Klopferspitz 19, 82152 Martinsried, Germany(1).
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10
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F 16915 prevents heart failure-induced atrial fibrillation: a promising new drug as upstream therapy. Naunyn Schmiedebergs Arch Pharmacol 2014; 387:667-77. [DOI: 10.1007/s00210-014-0975-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 03/12/2014] [Indexed: 11/26/2022]
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11
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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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12
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Goo S, Han J, Nisbet LA, LeGrice IJ, Taberner AJ, Loiselle DS. Dietary supplementation with either saturated or unsaturated fatty acids does not affect the mechanoenergetics of the isolated rat heart. Physiol Rep 2014; 2:e00272. [PMID: 24760525 PMCID: PMC4002251 DOI: 10.1002/phy2.272] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
It is generally recognized that increased consumption of polyunsaturated fatty acids, fish oil (FO) in particular, is beneficial to cardiac and cardiovascular health, whereas equivalent consumption of saturated fats is deleterious. In this study, we explore this divergence, adopting a limited purview: The effect of dietary fatty acids on the mechanoenergetics of the isolated heart per se. Mechanical indices of interest include left‐ventricular (LV) developed pressure, stroke work, cardiac output, coronary perfusion, and LV power. The principal energetic index is whole‐heart oxygen consumption, which we subdivide into its active and basal moieties. The primary mechanoenergetic index of interest is cardiac efficiency, the ratio of work performance to metabolic energy expenditure. Wistar rats were divided into three Diet groups and fed, ad libitum, reference (REF), fish oil‐supplemented (FO), or saturated fatty acid‐supplemented (SFA) food for 6 weeks. At the end of the dietary period, hearts were excised, mounted in a working‐heart rig, and their mechanoenergetic performance quantified over a range of preloads and afterloads. Analyses of Variance revealed no difference in any of the individual mechanoenergetic indices among the three Diet groups. In particular, we found no effect of prior dietary supplementation with either saturated or unsaturated fatty acids on the global efficiency of the heart. Literature reports have claimed profound effects of dietary supplementation with either saturated or polyunsaturated fatty acids on the contractile efficiency of the heart – diminishing and enhancing efficiency, respectively. We have mimicked the experimental protocols used in those reports and find no effect of diet on any index of cardiac mechanoenergetics, including efficiency.
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Affiliation(s)
- Soyeon Goo
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - June‐Chiew Han
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Linley A. Nisbet
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Ian J. LeGrice
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Andrew J. Taberner
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
- Department of Engineering Science, The University of Auckland, Auckland, New Zealand
| | - Denis S. Loiselle
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
- Department of Physiology, The University of Auckland, Auckland, New Zealand
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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: 305] [Impact Index Per Article: 30.5] [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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14
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Goo S, Han JC, Nisbet LA, LeGrice IJ, Taberner AJ, Loiselle DS. Dietary pre-exposure of rats to fish oil does not enhance myocardial efficiency of isolated working hearts or their left ventricular trabeculae. J Physiol 2014; 592:1795-808. [PMID: 24535444 DOI: 10.1113/jphysiol.2013.269977] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Numerous epidemiological studies, supported by clinical and experimental findings, have suggested beneficial effects of dietary fish or fish oil supplementation on cardiovascular health. One such experimental study showed a profound (100%) increase in myocardial efficiency (i.e. the ratio of work output to metabolic energy input) of the isolated whole heart, achieved by a corresponding decrease in the rate of myocardial oxygen consumption. However, a number of other investigations have returned null results on the latter energetic index. Such conflicting findings have motivated us to undertake a re-examination. To that effect, we investigated the effects of dietary fatty acid supplementation on myocardial mechano-energetics, with our primary focus on cardiac efficiency. We used both isolated hearts and isolated left ventricular trabeculae of rats fed with one of three distinct diets: reference (REF), fish oil-supplemented (FO) or saturated fat-supplemented (SFA). For all three groups, and at both spatial levels, we supplied 10 mm glucose as the exogenous metabolic substrate. In the working heart experiments, we found no difference in the average mechanical efficiency among the three dietary groups: 14.8 ± 1.1% (REF), 13.9 ± 0.6% (FO) and 13.6 ± 0.7% (SFA). Likewise, we observed no difference in peak mechanical efficiency of left ventricular trabeculae among the REF, FO and SFA groups: 13.3 ± 1.4, 11.2 ± 2.2 and 12.5 ± 1.5%, respectively. We conclude that there is no effect of a period of pre-exposure to a diet supplemented with either fish oil or saturated fatty acids on the efficiency of the myocardium at either spatial level: tissue or whole heart.
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Affiliation(s)
- Soyeon Goo
- Department of Physiology, The University of Auckland, Private Bag 92019, Auckland, New Zealand.
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15
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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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16
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Evaluation of docosahexaenoic acid in a dog model of hypertension induced left ventricular hypertrophy. J Cardiovasc Transl Res 2013; 6:1000-10. [PMID: 24065618 DOI: 10.1007/s12265-013-9511-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Accepted: 09/10/2013] [Indexed: 12/19/2022]
Abstract
Marine n-3 polyunsaturated fatty acids alter cardiac phospholipids and prevent cardiac pathology in rodents subjected to pressure overload. This approach has not been evaluated in humans or large animals with hypertension-induced pathological hypertrophy. We evaluated docosahexaenoic acid (DHA) in old female dogs with hypertension caused by 16 weeks of aldosterone infusion. Aldosterone-induced hypertension resulted in concentric left ventricular (LV) hypertrophy and impaired diastolic function in placebo-treated dogs. DHA supplementation increased DHA and depleted arachidonic acid in cardiac phospholipids, but did not improve LV parameters compared to placebo. Surprisingly, DHA significantly increased serum aldosterone concentration and blood pressure compared to placebo. Cardiac mitochondrial yield was decreased in placebo-treated hypertensive dogs compared to normal animals, which was prevented by DHA. Extensive analysis of mitochondrial function found no differences between DHA and placebo groups. In conclusion, DHA did not favorably impact mitochondrial or LV function in aldosterone hypertensive dogs.
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17
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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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18
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Ramadeen A, Connelly KA, Leong-Poi H, Hu X, Fujii H, Laurent G, Domenichiello AF, Bazinet RP, Dorian P. Docosahexaenoic Acid, but Not Eicosapentaenoic Acid, Supplementation Reduces Vulnerability to Atrial Fibrillation. Circ Arrhythm Electrophysiol 2012; 5:978-83. [DOI: 10.1161/circep.112.971515] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background—
The potential health benefits of ω-3 polyunsaturated fatty acids (PUFAs) usually are studied using a combination of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). This combination reduces vulnerability to experimentally induced atrial fibrillation (AF). It is unknown whether EPA and DHA have differential effects when taken alone. Using a model of pacing-induced atrial hemodynamic overload, we investigated the individual effects of EPA and DHA on vulnerability to AF and atrial remodeling.
Methods and Results—
Thirty-four dogs were randomized into 3 groups, all of which underwent simultaneous atrial and ventricular pacing at 220 beats per minute for 14 days. One group received purified DHA (≈1 g/d) orally for 21 days beginning 7 days before pacing began. Similarly, 1 group received ≈1 g/d purified EPA. In a third (control) group (No-PUFAs), 8 dogs received ≈1 g/d olive oil, and 12 were unsupplemented. Electrophysiological and echocardiographic measurements were taken at baseline and 21 days. Atrial tissue samples were collected at 21 days for histological and molecular analyses. Persistent AF inducibility was significantly reduced by DHA compared with No-PUFAs median [25–75 percentiles], 0% [0%–3%] for DHA versus 3.1% [2.2%–11%] for No-PUFAs;
P
=0.007) but not by EPA (3.4% [1.9%–8.9%]). DHA also reduced atrial fibrosis compared with No-PUFAs (11±6% versus 20±4%, respectively;
P
<0.05), whereas EPA did not (15±5%;
P
>0.05).
Conclusions—
DHA is more effective than EPA in attenuating AF vulnerability and atrial remodeling in structural remodeling–induced AF.
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Affiliation(s)
- Andrew Ramadeen
- From the Keenan Research Centre in the Li Ka Shing Knowledge Institute (A.R., K.A.C., H.L.-P., X.H., H.F., P.D.), Division of Cardiology (K.A.C., H.L.-P., P.D.), St. Michael’s Hospital, Toronto, Ontario, Canada; Department of Pharmacology and Toxicology (A.R., P.D.), Cardiovascular Sciences Collaborative Program (A.R., P.D.), Department of Medicine (K.A.C., H.L.-P., P.D.), and Department of Nutritional Sciences (A.F.D., R.P.B.), University of Toronto, Toronto, Ontario, Canada; and Department of
| | - Kim A. Connelly
- From the Keenan Research Centre in the Li Ka Shing Knowledge Institute (A.R., K.A.C., H.L.-P., X.H., H.F., P.D.), Division of Cardiology (K.A.C., H.L.-P., P.D.), St. Michael’s Hospital, Toronto, Ontario, Canada; Department of Pharmacology and Toxicology (A.R., P.D.), Cardiovascular Sciences Collaborative Program (A.R., P.D.), Department of Medicine (K.A.C., H.L.-P., P.D.), and Department of Nutritional Sciences (A.F.D., R.P.B.), University of Toronto, Toronto, Ontario, Canada; and Department of
| | - Howard Leong-Poi
- From the Keenan Research Centre in the Li Ka Shing Knowledge Institute (A.R., K.A.C., H.L.-P., X.H., H.F., P.D.), Division of Cardiology (K.A.C., H.L.-P., P.D.), St. Michael’s Hospital, Toronto, Ontario, Canada; Department of Pharmacology and Toxicology (A.R., P.D.), Cardiovascular Sciences Collaborative Program (A.R., P.D.), Department of Medicine (K.A.C., H.L.-P., P.D.), and Department of Nutritional Sciences (A.F.D., R.P.B.), University of Toronto, Toronto, Ontario, Canada; and Department of
| | - Xudong Hu
- From the Keenan Research Centre in the Li Ka Shing Knowledge Institute (A.R., K.A.C., H.L.-P., X.H., H.F., P.D.), Division of Cardiology (K.A.C., H.L.-P., P.D.), St. Michael’s Hospital, Toronto, Ontario, Canada; Department of Pharmacology and Toxicology (A.R., P.D.), Cardiovascular Sciences Collaborative Program (A.R., P.D.), Department of Medicine (K.A.C., H.L.-P., P.D.), and Department of Nutritional Sciences (A.F.D., R.P.B.), University of Toronto, Toronto, Ontario, Canada; and Department of
| | - Hiroko Fujii
- From the Keenan Research Centre in the Li Ka Shing Knowledge Institute (A.R., K.A.C., H.L.-P., X.H., H.F., P.D.), Division of Cardiology (K.A.C., H.L.-P., P.D.), St. Michael’s Hospital, Toronto, Ontario, Canada; Department of Pharmacology and Toxicology (A.R., P.D.), Cardiovascular Sciences Collaborative Program (A.R., P.D.), Department of Medicine (K.A.C., H.L.-P., P.D.), and Department of Nutritional Sciences (A.F.D., R.P.B.), University of Toronto, Toronto, Ontario, Canada; and Department of
| | - Gabriel Laurent
- From the Keenan Research Centre in the Li Ka Shing Knowledge Institute (A.R., K.A.C., H.L.-P., X.H., H.F., P.D.), Division of Cardiology (K.A.C., H.L.-P., P.D.), St. Michael’s Hospital, Toronto, Ontario, Canada; Department of Pharmacology and Toxicology (A.R., P.D.), Cardiovascular Sciences Collaborative Program (A.R., P.D.), Department of Medicine (K.A.C., H.L.-P., P.D.), and Department of Nutritional Sciences (A.F.D., R.P.B.), University of Toronto, Toronto, Ontario, Canada; and Department of
| | - Anthony F. Domenichiello
- From the Keenan Research Centre in the Li Ka Shing Knowledge Institute (A.R., K.A.C., H.L.-P., X.H., H.F., P.D.), Division of Cardiology (K.A.C., H.L.-P., P.D.), St. Michael’s Hospital, Toronto, Ontario, Canada; Department of Pharmacology and Toxicology (A.R., P.D.), Cardiovascular Sciences Collaborative Program (A.R., P.D.), Department of Medicine (K.A.C., H.L.-P., P.D.), and Department of Nutritional Sciences (A.F.D., R.P.B.), University of Toronto, Toronto, Ontario, Canada; and Department of
| | - Richard P. Bazinet
- From the Keenan Research Centre in the Li Ka Shing Knowledge Institute (A.R., K.A.C., H.L.-P., X.H., H.F., P.D.), Division of Cardiology (K.A.C., H.L.-P., P.D.), St. Michael’s Hospital, Toronto, Ontario, Canada; Department of Pharmacology and Toxicology (A.R., P.D.), Cardiovascular Sciences Collaborative Program (A.R., P.D.), Department of Medicine (K.A.C., H.L.-P., P.D.), and Department of Nutritional Sciences (A.F.D., R.P.B.), University of Toronto, Toronto, Ontario, Canada; and Department of
| | - Paul Dorian
- From the Keenan Research Centre in the Li Ka Shing Knowledge Institute (A.R., K.A.C., H.L.-P., X.H., H.F., P.D.), Division of Cardiology (K.A.C., H.L.-P., P.D.), St. Michael’s Hospital, Toronto, Ontario, Canada; Department of Pharmacology and Toxicology (A.R., P.D.), Cardiovascular Sciences Collaborative Program (A.R., P.D.), Department of Medicine (K.A.C., H.L.-P., P.D.), and Department of Nutritional Sciences (A.F.D., R.P.B.), University of Toronto, Toronto, Ontario, Canada; and Department of
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19
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Sankaranarayanan R, Venetucci L. Are the anti-arrhythmic effects of omega-3 fatty acids due to modulation of myocardial calcium handling? Front Physiol 2012; 3:373. [PMID: 23060805 PMCID: PMC3461578 DOI: 10.3389/fphys.2012.00373] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Accepted: 08/30/2012] [Indexed: 11/15/2022] Open
Abstract
Both animal and clinical studies have demonstrated that omega-3 fatty acids have anti-arrhythmic properties. It has been suggested that these anti-arrhythmic effects are due to modulation of the activity of various myocardial calcium handling proteins such as ryanodine receptor (RyR), L-type calcium current and sodium/calcium exchanger. In this article, we review all the data available on the effects of omega-3 fatty acids on ventricular myocardial calcium handling. In addition we highlight some unanswered questions and discuss possible therapeutic benefits of omega-3 fatty acids.
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Affiliation(s)
- Rajiv Sankaranarayanan
- Cardiovascular Research Group, University of Manchester Manchester, UK ; Manchester Royal Infirmary, Manchester Heart Centre Manchester, UK
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20
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Carter JR, Schwartz CE, Yang H, Joyner MJ. Fish oil and neurovascular control in humans. Am J Physiol Heart Circ Physiol 2012; 303:H450-6. [PMID: 22707560 DOI: 10.1152/ajpheart.00353.2012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The antihypertensive influence of fish oil is controversial, and the mechanisms remain unclear. Because the inverse relation between fish oil and hypertension appears to be partially dependent on the degree of hypertension, we tested the hypothesis that fish oil would elicit more dramatic reductions in mean arterial pressure (MAP) and muscle sympathetic nerve activity (MSNA) in prehypertensive (PHT) compared with normotensive (NT) subjects. Resting MAP, MSNA, and heart rate (HR) were examined before and after 8 wk of fish oil (9 g/day; 1.6 g eicosapentaenoic acid and 1.1 g docosahexaenoic acid) or placebo (olive oil; 9 g/day) in 38 NT (19 fish oil; 19 placebo) and 29 PHT (15 fish oil; 14 placebo) volunteers. Fish oil did not alter resting MAP, MSNA, or HR in either NT (80 ± 1 to 80 ± 1 mmHg; 11 ± 2 to 10 ± 1 bursts/min; 71 ± 2 to 71 ± 2 beats/min) or PHT (88 ± 2 to 87 ± 1 mmHg; 11 ± 2 to 10 ± 2 bursts/min; 73 ± 2 to 73 ± 2 beats/min) subjects. When NT and PHT groups were consolidated, analysis of covariance confirmed that pretreatment resting MAP was not associated with changes in MSNA after fish oil. In contrast, pretreatment resting HR was correlated with changes in MSNA (r = 0.47; P = 0.007) and MAP (r = 0.42; P < 0.007) after fish oil but not placebo. In conclusion, fish oil did not alter sympathetic neural control in NT or PHT subjects. However, our findings suggest that fish oil is associated with modest sympathoinhibition in individuals with higher resting heart rates, a finding that is consistent with a recent meta-analysis examining the relations among fish oil, HR, and the risk of cardiovascular disease.
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Affiliation(s)
- Jason R Carter
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, Michigan 49931, USA.
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21
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Rix TA, Mortensen LM, Schmidt EB. Fish, Marine n-3 Fatty Acids, and Atrial Fibrillation - Experimental Data and Clinical Effects. Front Physiol 2012; 3:152. [PMID: 22654766 PMCID: PMC3360493 DOI: 10.3389/fphys.2012.00152] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Accepted: 05/02/2012] [Indexed: 01/22/2023] Open
Abstract
Marine n−3 polyunsaturated fatty acids (PUFA) may have beneficial effects in relation to atrial fibrillation (AF) with promising data from experimental animal studies, however, results from studies in humans have been inconsistent. This review evaluates the mechanisms of action of marine n−3 PUFA in relation to AF based on experimental data and provides a status on the evidence obtained from observational studies and interventional trials. In conclusion, there is growing evidence for an effect of marine n−3 PUFA in prevention and treatment of AF. However, further studies are needed to establish which patients are more likely to benefit from n−3 PUFA, the timing of treatment, and dosages.
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Affiliation(s)
- Thomas Andersen Rix
- Department of Cardiology, Aalborg AF Study Group, Center for Cardiovascular Research, Aalborg Hospital, Aarhus University Hospital Aalborg, Denmark
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22
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Bonilla IM, Sridhar A, Györke S, Cardounel AJ, Carnes CA. Nitric oxide synthases and atrial fibrillation. Front Physiol 2012; 3:105. [PMID: 22536189 PMCID: PMC3332924 DOI: 10.3389/fphys.2012.00105] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2012] [Accepted: 04/02/2012] [Indexed: 11/13/2022] Open
Abstract
Oxidative stress has been implicated in the pathogenesis of atrial fibrillation. There are multiple systems in the myocardium which contribute to redox homeostasis, and loss of homeostasis can result in oxidative stress. Potential sources of oxidants include nitric oxide synthases (NOS), which normally produce nitric oxide in the heart. Two NOS isoforms (1 and 3) are normally expressed in the heart. During pathologies such as heart failure, there is induction of NOS 2 in multiple cell types in the myocardium. In certain conditions, the NOS enzymes may become uncoupled, shifting from production of nitric oxide to superoxide anion, a potent free radical and oxidant. Multiple lines of evidence suggest a role for NOS in the pathogenesis of atrial fibrillation. Therapeutic approaches to reduce atrial fibrillation by modulation of NOS activity may be beneficial, although further investigation of this strategy is needed.
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Affiliation(s)
- Ingrid M Bonilla
- College of Pharmacy, The Ohio State University Columbus, OH, USA
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23
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von Schacky C. Omega-3 Fatty acids: anti-arrhythmic, pro-arrhythmic, or both? Front Physiol 2012; 3:88. [PMID: 22529815 PMCID: PMC3327892 DOI: 10.3389/fphys.2012.00088] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Accepted: 03/23/2012] [Indexed: 11/13/2022] Open
Abstract
This review focuses on developments after 2008, when the topic was last reviewed by the author. Pertinent publications were found by medline searches and in the author’s personal data base. Prevention of atrial fibrillation (AF) was investigated in a number of trials, sparked by one positive report on the effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), considerations of upstream therapy, data from electrophysiologic laboratories and animal experiments. If EPA + DHA prevent postoperative AF, the effect is probably smaller than initially expected. The same is probably true for maintenance of sinus rhythm after cardioversion and for new-onset AF. Larger trials are currently ongoing. Prevention of ventricular arrhythmias was studied in carriers of an implanted cardioverter-defibrillator, with no clear results. This might have been due to a broad definition of the primary endpoint, including any ventricular arrhythmia and any action of the device. Epidemiologic studies support the contention that high levels of EPA + DHA prevent sudden cardiac death (SCD). However, since SCD is a rare occurrence, it is difficult to conduct an adequately powered trial. In patients with congestive heart failure, EPA + DHA reduced total mortality and rehospitalizations, but not SCD or presumed arrhythmic death. Of three trials in patients after a myocardial infarction, two were inadequately powered, and in one, the dose might have been too low. Taken together, while epidemiologic studies support an inverse relation between EPA + DHA and occurrence of SCD or arrhythmic death, demonstrating this effect in intervention trials remained elusive so far. A pro-arrhythmic effect of EPA + DHA has not been seen in intervention studies, and results of epidemiologic and animal studies also rather argue against such an effect. A different, and probably more productive, perspective is provided by a standardized analytical assessment of a person’s status in EPA + DHA by use of the omega-3 index, EPA + DHA in red cell fatty acids. In populations with a high omega-3 index, SCD is rare. Intervention trials can become more effective by including a low omega-3 index into the inclusion criteria, thus creating a study population more likely to demonstrate an effect of EPA + DHA. This is especially relevant in case of rare endpoints, like new-onset AF or SCD.
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Affiliation(s)
- C von Schacky
- Preventive Cardiology, Medizinische Klinik and Poliklinik I, Ludwig Maximilians-University Munich Munich, Germany
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24
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Billman GE. Effect of dietary omega-3 polyunsaturated Fatty acids on heart rate and heart rate variability in animals susceptible or resistant to ventricular fibrillation. Front Physiol 2012; 3:71. [PMID: 22470351 PMCID: PMC3313477 DOI: 10.3389/fphys.2012.00071] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Accepted: 03/12/2012] [Indexed: 11/27/2022] Open
Abstract
The consumption of omega-3 polyunsaturated fatty acids (n−3 PUFAs) has been reported to reduce cardiac mortality following myocardial infarction as well as to decrease resting heart rate (HR) and increase HR variability (HRV). However, it has not been established whether n−3 PUFAs exhibit the same actions on HR and HRV in individuals known to be either susceptible or resistant to ventricular fibrillation (VF). Therefore, HR and HRV (high frequency and total R–R interval variability) were evaluated before and 3 months after n−3 PUFA treatment in dogs with healed myocardial infarction that were either susceptible (VF+, n = 31) or resistant (VF−, n = 31) to ventricular tachyarrhythmias induced by a 2-min coronary artery occlusion during the last minute of a submaximal exercise test. HR and HRV were evaluated at rest, during submaximal exercise and in response to acute myocardial ischemia at rest before and after either placebo (1 g/day, corn oil, VF+, n = 9; VF− n = 8) or n−3 PUFA (docosahexaenoic acid + eicosapentaenoic acid ethyl esters, 1–4 g/day, VF+, n = 22; VF−, n = 23) treatment for 3 months. The n−3 PUFA treatment elicited similar increases in red blood cell membrane, right atrial, and left ventricular n−3 PUFA levels in both the VF+ and VF− dogs. The n−3 PUFA treatment also provoked similar reductions in baseline HR and increases in baseline HRV in both groups that resulted in parallel shifts in the response to either exercise or acute myocardial ischemia (that is, the change in these variables induced by physiological challenges was not altered after n−3 PUFA treatment). These data demonstrate that dietary n−3 PUFA decreased HR and increased HRV to a similar extent in animals known to be prone to or resistant to malignant cardiac tachyarrhythmias.
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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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Mozaffarian D, Wu JHY. (n-3) fatty acids and cardiovascular health: are effects of EPA and DHA shared or complementary? J Nutr 2012; 142:614S-625S. [PMID: 22279134 PMCID: PMC3278271 DOI: 10.3945/jn.111.149633] [Citation(s) in RCA: 237] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Revised: 09/21/2011] [Accepted: 10/03/2011] [Indexed: 01/03/2023] Open
Abstract
Considerable research supports cardiovascular benefits of consuming omega-3 PUFA, also known as (n-3) PUFA, from fish or fish oil. Whether individual long-chain (n-3) PUFA have shared or complementary effects is not well established. We reviewed evidence for dietary and endogenous sources and cardiovascular effects on biologic pathways, physiologic risk factors, and clinical endpoints of EPA [20:5(n-3)], docosapentaenoic acid [DPA, 22:5(n-3)], and DHA [22:6(n-3)]. DHA requires direct dietary consumption, with little synthesis from or retroconversion to DPA or EPA. Whereas EPA is also largely derived from direct consumption, EPA can also be synthesized in small amounts from plant (n-3) precursors, especially stearidonic acid. In contrast, DPA appears principally derived from endogenous elongation from EPA, and DPA can also undergo retroconversion back to EPA. In experimental and animal models, both EPA and DHA modulate several relevant biologic pathways, with evidence for some differential benefits. In humans, both fatty acids lower TG levels and, based on more limited studies, favorably affect cardiac diastolic filling, arterial compliance, and some metrics of inflammation and oxidative stress. All three (n-3) PUFA reduce ex vivo platelet aggregation and DHA also modestly increases LDL and HDL particle size; the clinical relevance of such findings is uncertain. Combined EPA+DHA or DPA+DHA levels are associated with lower risk of fatal cardiac events and DHA with lower risk of atrial fibrillation, suggesting direct or indirect benefits of DHA for cardiac arrhythmias (although not excluding similar benefits of EPA or DPA). Conversely, EPA and DPA, but not DHA, are associated with lower risk of nonfatal cardiovascular endpoints in some studies, and purified EPA reduced risk of nonfatal coronary syndromes in one large clinical trial. Overall, for many cardiovascular pathways and outcomes, identified studies of individual (n-3) PUFA were relatively limited, especially for DPA. Nonetheless, the present evidence suggests that EPA and DHA have both shared and complementary benefits. Based on current evidence, increasing consumption of either would be advantageous compared to little or no consumption. Focusing on their combined consumption remains most prudent given the potential for complementary effects and the existing more robust literature on cardiovascular benefits of their combined consumption as fish or fish oil for cardiovascular benefits.
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Affiliation(s)
- Dariush Mozaffarian
- Division of Cardiovascular Medicine and Channing Laboratory, Brigham and Women's Hospital, Boston, MA, USA.
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Contractile strength during variable heart duration is species and preload dependent. J Biomed Biotechnol 2011; 2011:294204. [PMID: 22131801 PMCID: PMC3205780 DOI: 10.1155/2011/294204] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Accepted: 08/15/2011] [Indexed: 12/24/2022] Open
Abstract
We investigate the effect of beat-to-beat variability on cardiac contractility. Cardiac trabeculae were isolated from the right ventricle of rabbits and beagle dogs and stimulated to isometrically contract, alternating between fixed steady state versus variable interbeat intervals. Trabeculae were stimulated at physiologically relevant frequencies for each species (dog 1 and 4 Hz; rabbit 2 and 4 Hz) intercalating fixed periods with 40% variability. A subset of the trabeculae (at 90% of optimal length) was stretched prior to stimulation between 5 and 13% and stimulated at the same frequencies with a fixed versus 40% variation. Fixed rate response at the same base frequency was measured before and after each variable period and the average force reported. In canine preparations no change in force was observed as a result of the imposed variability in beat-to-beat duration. In the rabbit, we observed a nonsignificant decrease in force between fixed and variable pacing at both 2 and 4 Hz (n = 8) when 40% variability was introduced. When a 5% and 13% stretch was applied, the correlation coefficient sharply increased, indicating a more prominent impact of the prebeat duration on the following cycle with higher preload.
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Xu Y, Monasky MM, Hiranandani N, Haizlip KM, Billman GE, Janssen PML. Effect of twitch interval duration on the contractile function of subsequent twitches in isolated rat, rabbit, and dog myocardium under physiological conditions. J Appl Physiol (1985) 2011; 111:1159-67. [PMID: 21778421 DOI: 10.1152/japplphysiol.01170.2010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Many studies have shown that a change in stimulation frequency leads to altered contractility of the myocardium. However, it remains unclear what changes occur directly after a change in frequency and which ones are a result of the slow processes that lead to the altered homeostasis, which develops after a change in stimulation frequency. To distinguish the immediate from the slow responses, we assessed contractile function in two species that have distinctively different calcium (Ca(2+))-handling properties using a recently developed, randomized pacing protocol. In isolated dog and rat right ventricular trabeculae, twitch contractions at five different cycle lengths within the physiologic range of each species were randomized around a steady-state frequency. We found, in both species, that the duration of the cycle length just prior to the analyzed twitch (primary) positively correlated with the increased force of the analyzed twitch. In sharp contrast, the cycle lengths, one and two more removed from the analyzed twitch ("secondary" and "tertiary"), displayed a negative correlation with force of the analyzed twitch. In additional experiments, assessment of intracellular Ca(2+) transients in rabbit trabeculae revealed that diastolic Ca(2+) levels were closely correlated to contractile function outcome. The relative contribution of the primary cycle length was different between dog (51%) and rat (71%), whereas in neither species was a significant effect on relaxation time observed. With the use of randomized cycle lengths, we have distinguished the intrinsic response from the signaling-mediated effects of frequency-dependent activation on myofilament properties and Ca(2+) handling.
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Affiliation(s)
- Ying Xu
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, Ohio, USA
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Billman GE, Harris WS. Effect of dietary omega-3 fatty acids on the heart rate and the heart rate variability responses to myocardial ischemia or submaximal exercise. Am J Physiol Heart Circ Physiol 2011; 300:H2288-99. [PMID: 21460198 DOI: 10.1152/ajpheart.00140.2011] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The consumption of omega-3 polyunsaturated fatty acids (n-3 PUFAs) has been reported to decrease resting heart rate (HR) and increase heart rate variability (HRV). However, the effects of n-3 PUFAs on these variables in response to a physiological stress (e.g., exercise or acute myocardial ischemia), particularly in postmyocardial infarction (MI) patients, are unknown. Therefore, HR and HRV (high frequency and total R-R interval variability) were evaluated at rest, during submaximal exercise, and during a 2-min coronary artery occlusion at rest and before and 3 mo after n-3 PUFA treatment in dogs with healed MI (n = 59). The dogs were randomly assigned to either placebo (1 g/day corn oil, n = 19) or n-3 PUFA supplement (docosahexaenoic acid + eicosapentaenoic acid ethyl esters; 1 g/day, n = 6; 2 g/day, n = 12; or 4 g/day, n = 22) groups. The treatment elicited significant (P < 0.01) dose-dependent increases in right atrial n-3 PUFA levels but dose-independent reductions in resting HR and increases in resting HRV. In contrast, n-3 PUFAs did not attenuate the large changes in HR or HRV induced by either the coronary occlusion or submaximal exercise. These data demonstrate that dietary n-3 PUFA decreased resting (i.e., preexercise or preocclusion) HR and increased resting HRV but did not alter the cardiac response to physiologic challenges.
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Affiliation(s)
- George E Billman
- Dept. of Physiology and Cell Biology, Ohio State Univ., 304 Hamilton Hall, 1645 Neil Ave., Columbus, OH 43210-1218, USA.
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Richardson ES, Iaizzo PA, Xiao YF. Electrophysiological mechanisms of the anti-arrhythmic effects of omega-3 fatty acids. J Cardiovasc Transl Res 2010; 4:42-52. [PMID: 21125434 DOI: 10.1007/s12265-010-9243-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2010] [Accepted: 11/10/2010] [Indexed: 11/28/2022]
Abstract
Heart rhythm disorders, or arrhythmias, are a leading cause of morbidity and mortality worldwide. Omega-3 polyunsaturated fatty acids (ω3PUFAs), commonly found in fish oils and plant seeds, have recently emerged as potential anti-arrhythmic agents. The purpose of this review is to summarize the electrophysiological basis of the anti-arrhythmic properties of ω3PUFAs from clinical, animal, and cellular research. Evidence of the anti-arrhythmic effects of ω3PUFAs originated from epidemiological studies that correlated a low incidence of sudden cardiac death with high dietary ω3PUFA intake. Subsequently, multiple clinical trials have confirmed the therapeutic effects of ω3PUFAs in preventing sudden cardiac death and multiple other arrhythmia-related disorders. This has led basic scientists to investigate the effects of ω3PUFAs on several ion channels including sodium, potassium, and calcium channels, as well as Na/Ca exchangers. Therefore, ω3PUFAs may hold promise as safe and effective anti-arrhythmic agents. Nevertheless, further research is needed in areas such as: (1) identifying which form(s) of ω3PUFAs (i.e., phospholipid, triglyceride, or free) is (are) responsible for anti-arrhythmic actions; and (2) developing reproducible methods for delivery so that the appropriate form and concentration may be present at the target site to prevent and treat arrhythmias.
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Affiliation(s)
- Eric S Richardson
- Departments of Biomedical Engineering and Surgery, University of Minnesota, B172 Mayo, MMC 195, 420 Delaware St. SE, Minneapolis, MN 55455, USA
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Den Ruijter HM, Verkerk AO, Coronel R. Incorporated fish oil fatty acids prevent action potential shortening induced by circulating fish oil fatty acids. Front Physiol 2010; 1:149. [PMID: 21423389 PMCID: PMC3059945 DOI: 10.3389/fphys.2010.00149] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2010] [Accepted: 10/25/2010] [Indexed: 11/13/2022] Open
Abstract
Increased consumption of fatty fish, rich in omega-3-polyunsaturated fatty acids (ω3-PUFAs) reduces the severity and number of arrhythmias. Long-term ω3-PUFA-intake modulates the activity of several cardiac ion channels leading to cardiac action potential shortening. Circulating ω3-PUFAs in the bloodstream and incorporated ω3-PUFAs in the cardiac membrane have a different mechanism to shorten the action potential. It is, however, unknown whether circulating ω3-PUFAs in the bloodstream enhance or diminish the effects of incorporated ω3-PUFAs. In the present study, we address this issue. Rabbits were fed a diet rich in fish oil (ω3) or sunflower oil (ω9, as control) for 3 weeks. Ventricular myocytes were isolated by enzymatic dissociation and action potentials were measured using the perforated patch-clamp technique in the absence and presence of acutely administered ω3-PUFAs. Plasma of ω3 fed rabbits contained more free eicosapentaenoic acid (EPA) and isolated myocytes of ω3 fed rabbits contained higher amounts of both EPA and docosahexaenoic acid (DHA) in their sarcolemma compared to control. In the absence of acutely administered fatty acids, ω3 myocytes had a shorter action potential with a more negative plateau than ω9 myocytes. In the ω9 myocytes, but not in the ω3 myocytes, acute administration of a mixture of EPA + DHA shortened the action potential significantly. From these data we conclude that incorporated ω3-PUFAs into the sarcolemma and acutely administered ω3 fatty acids do not have a cumulative effect on action potential duration and morphology. As a consequence, patients with a high cardiac ω3-PUFA status will probably not benefit from short term ω3 supplementation as an antiarrhythmic therapy.
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Affiliation(s)
- Hester M Den Ruijter
- Department of Experimental Cardiology, Heart Failure Research Center, Academic Medical Center, University of Amsterdam Amsterdam, Netherlands
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Hiranandani N, Billman GE, Janssen PML. Effects of hydroxyl radical induced-injury in atrial versus ventricular myocardium of dog and rabbit. Front Physiol 2010; 1:25. [PMID: 21423367 PMCID: PMC3059949 DOI: 10.3389/fphys.2010.00025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2010] [Accepted: 07/22/2010] [Indexed: 11/13/2022] Open
Abstract
Despite the widespread use of ventricular tissue in the investigation involving hydroxyl radical Aim: (OH*) injury, one of the most potent mediators in ischemia-reperfusion injury, little is known about the impact on atrial myocardium. In this study we thus compared the OH*-induced injury response between atrial and right ventricular muscles from both rabbits and dogs under identical experimental conditions. Methods: Small, contracting ventricular and atrial rabbit and dog trabeculae were directly exposed to OH*, and contractile properties were examined and quantified. Results: A brief OH* exposure led to transient rigor like contracture with marked elevation of diastolic tension and depression of developed force. Although the injury response showed similarities between atrial and ventricular myocardium, there were significant differences as well. In rabbit atrial muscles, the development of the contracture and its peak was much faster as compared to ventricular muscles. Also, at the peak of contracture, both rabbit and dog atrial muscles show a lesser degree of contractile dysfunction. Conclusion:These results indicate that both atrial and ventricular muscles develop a rigor-like contracture after acute OH*-induced injury, and atrial muscles showed a lesser degree of contractile dysfunction. Comparison of dog versus rabbit tissue shows that the response was similar in magnitude, but slower to develop in dog tissue.
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Affiliation(s)
- Nitisha Hiranandani
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University Columbus, OH, USA
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O'Shea KM, Chess DJ, Khairallah RJ, Hecker PA, Lei B, Walsh K, Des Rosiers C, Stanley WC. ω-3 Polyunsaturated fatty acids prevent pressure overload-induced ventricular dilation and decrease in mitochondrial enzymes despite no change in adiponectin. Lipids Health Dis 2010; 9:95. [PMID: 20819225 PMCID: PMC2939588 DOI: 10.1186/1476-511x-9-95] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2010] [Accepted: 09/06/2010] [Indexed: 01/04/2023] Open
Abstract
Background Pathological left ventricular (LV) hypertrophy frequently progresses to dilated heart failure with suppressed mitochondrial oxidative capacity. Dietary marine ω-3 polyunsaturated fatty acids (ω-3 PUFA) up-regulate adiponectin and prevent LV dilation in rats subjected to pressure overload. This study 1) assessed the effects of ω-3 PUFA on LV dilation and down-regulation of mitochondrial enzymes in response to pressure overload; and 2) evaluated the role of adiponectin in mediating the effects of ω-3 PUFA in heart. Methods Wild type (WT) and adiponectin-/- mice underwent transverse aortic constriction (TAC) and were fed standard chow ± ω-3 PUFA for 6 weeks. At 6 weeks, echocardiography was performed to assess LV function, mice were terminated, and mitochondrial enzyme activities were evaluated. Results TAC induced similar pathological LV hypertrophy compared to sham mice in both strains on both diets. In WT mice TAC increased LV systolic and diastolic volumes and reduced mitochondrial enzyme activities, which were attenuated by ω-3 PUFA without increasing adiponectin. In contrast, adiponectin-/- mice displayed no increase in LV end diastolic and systolic volumes or decrease in mitochondrial enzymes with TAC, and did not respond to ω-3 PUFA. Conclusion These findings suggest ω-3 PUFA attenuates cardiac pathology in response to pressure overload independent of an elevation in adiponectin.
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Affiliation(s)
- Karen M O'Shea
- Division of Cardiology and Department of Medicine, University of Maryland, Baltimore, MD, USA
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