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Costa ADS, Ghouri I, Johnston A, McGlynn K, McNair A, Bowman P, Malik N, Hurren J, Bingelis T, Dunne M, Smith GL, Kemi OJ. Electrically stimulated in vitro heart cell mimic of acute exercise reveals novel immediate cellular responses to exercise: Reduced contractility and metabolism, but maintained calcium cycling and increased myofilament calcium sensitivity. Cell Biochem Funct 2023; 41:1147-1161. [PMID: 37665041 PMCID: PMC10947300 DOI: 10.1002/cbf.3847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 08/14/2023] [Accepted: 08/21/2023] [Indexed: 09/05/2023]
Abstract
Cardiac cellular responses to acute exercise remain undescribed. We present a model for mimicking acute aerobic endurance exercise to freshly isolated cardiomyocytes by evoking exercise-like contractions over prolonged periods of time with trains of electrical twitch stimulations. We then investigated immediate contractile, Ca2+ , and metabolic responses to acute exercise in perfused freshly isolated left ventricular rat cardiomyocytes, after a matrix-design optimized protocol and induced a mimic for acute aerobic endurance exercise by trains of prolonged field twitch stimulations. Acute exercise decreased cardiomyocyte fractional shortening 50%-80% (p < .01). This was not explained by changes to intracellular Ca2+ handling (p > .05); rather, we observed a weak insignificant Ca2+ transient increase (p = .11), while myofilament Ca2+ sensitivity increased 20%-70% (p < .05). Acidic pH 6.8 decreased fractional shortening 20%-70% (p < .05) because of 20%-30% decreased Ca2+ transients (p < .05), but no difference occurred between control and acute exercise (p > .05). Addition of 1 or 10 mM La- increased fractional shortening in control (1 mM La- : no difference, p > .05; 10 mM La- : 20%-30%, p < .05) and acute exercise (1 mM La- : 40%-90%, p < .01; 10 mM La- : 50%-100%, p < .01) and rendered acute exercise indifferent from control (p > .05). Intrinsic autofluorescence showed a resting NADstate of 0.59 ± 0.04 and FADstate of 0.17 ± 0.03, while acute exercise decreased NADH/FAD ratio 8% (p < .01), indicating intracellular oxidation. In conclusion, we show a novel approach for studying immediate acute cardiomyocyte responses to aerobic endurance exercise. We find that acute exercise in cardiomyocytes decreases contraction, but Ca2+ handling and myofilament Ca2+ sensitivity compensate for this, while acidosis and reduced energy substrate and mitochondrial ATP generation explain this.
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Affiliation(s)
- Ana Da Silva Costa
- School of Cardiovascular and Metabolic Health, College of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowUK
- Graduate School, College of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowUK
| | - Iffath Ghouri
- School of Cardiovascular and Metabolic Health, College of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowUK
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical SciencesNewcastle UniversityNewcastle upon TyneUK
| | - Alexander Johnston
- School of Cardiovascular and Metabolic Health, College of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowUK
| | - Karen McGlynn
- School of Cardiovascular and Metabolic Health, College of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowUK
| | - Andrew McNair
- School of Cardiovascular and Metabolic Health, College of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowUK
| | - Peter Bowman
- School of Cardiovascular and Metabolic Health, College of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowUK
| | - Natasha Malik
- School of Cardiovascular and Metabolic Health, College of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowUK
| | - Johanne Hurren
- School of Cardiovascular and Metabolic Health, College of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowUK
| | - Tomas Bingelis
- School of Cardiovascular and Metabolic Health, College of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowUK
| | - Michael Dunne
- School of Cardiovascular and Metabolic Health, College of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowUK
| | - Godfrey L. Smith
- School of Cardiovascular and Metabolic Health, College of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowUK
| | - Ole J. Kemi
- School of Cardiovascular and Metabolic Health, College of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowUK
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Greenman AC, Diffee GM, Power AS, Wilkins GT, Gold OMS, Erickson JR, Baldi JC. Treadmill running increases the calcium sensitivity of myofilaments in diabetic rats. J Appl Physiol (1985) 2022; 132:1350-1360. [PMID: 35482324 DOI: 10.1152/japplphysiol.00785.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The cardiovascular benefits of regular exercise are unequivocal, yet patients with type 2 diabetes respond poorly to exercise due to a reduced cardiac reserve. The contractile response of diabetic cardiomyocytes to beta-adrenergic stimulation is attenuated, which may result in altered myofilament calcium sensitivity and post-translational modifications of cardiac troponin I (cTnI). Treadmill running increases myofilament calcium sensitivity in non‑diabetic rats, and thus we hypothesized that endurance training would increase calcium sensitivity of diabetic cardiomyocytes and alter site-specific phosphorylation of cTnI. Calcium sensitivity, or pCa50, was measured in Zucker Diabetic Fatty (ZDF) non-diabetic (nDM) and diabetic (DM) rat hearts after 8 weeks of either a sedentary (SED) or progressive treadmill running (TR) intervention. Skinned cardiomyocytes were connected to a capacitance-gauge transducer and a torque motor to measure force as a function of pCa (‑log[Ca2+]). Specific phospho-sites on cTnI and O‑GlcNAcylation were quantified by immunoblot and total protein phosphorylation by fluorescent gel staining (ProQ Diamond). The novel finding in this study was that training increased pCa50 in both DM and nDM cardiomyocytes (p = 0.009). Phosphorylation of cTnI amino acid residues Ser23/24, a crucial protein kinase A site, and Threonine (Thr)144, was lower in DM hearts, but there was no effect of training on site-specific phosphorylation. Additionally, total phosphorylation and O-GlcNAcylation levels were not different between SED and TR groups. These findings suggest that regular exercise may benefit the diabetic heart by specifically targeting myofilament contractile function.
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Affiliation(s)
- Angela Claire Greenman
- Department of Medicine, Otago Medical School, University of Otago, Dunedin, New Zealand.,Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.,HeartOtago, University of Otago, Dunedin, New Zealand
| | - Gary M Diffee
- Department of Kinesiology, University of Wisconsin-Madison, Madison, WI
| | - Amelia S Power
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.,HeartOtago, University of Otago, Dunedin, New Zealand
| | - Gerard T Wilkins
- Department of Medicine, Otago Medical School, University of Otago, Dunedin, New Zealand.,HeartOtago, University of Otago, Dunedin, New Zealand
| | - Olivia M S Gold
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.,HeartOtago, University of Otago, Dunedin, New Zealand
| | - Jeffrey R Erickson
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.,HeartOtago, University of Otago, Dunedin, New Zealand
| | - James C Baldi
- Department of Medicine, Otago Medical School, University of Otago, Dunedin, New Zealand.,HeartOtago, University of Otago, Dunedin, New Zealand
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Boldt K, Joumaa V, Turnbull J, Fedak PW, Herzog W. A high-whey-protein diet does not enhance mechanical and structural remodeling of cardiac muscle in response to aerobic exercise in rats. Phys Act Nutr 2022; 26:28-38. [PMID: 35510443 PMCID: PMC9081358 DOI: 10.20463/pan.2022.0005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 02/18/2022] [Accepted: 03/30/2022] [Indexed: 11/22/2022] Open
Abstract
PURPOSE Aerobic exercise training results in distinct structural and mechanical myocardial adaptations. In skeletal muscle, whey protein supplementation is effective in enhancing muscle adaptation following resistance exercise. However, it is unclear whether cardiac adaptation to aerobic exercise can be enhanced by systematic protein supplementation. METHODS Twelve-week-old rats were assigned to 12 weeks of either sedentary or aerobic exercise with either a standard (Sed+Standard, Ex+Standard) or high-protein (Sed+Pro, Ex+Pro) diet. Echocardiography was used to measure cardiac structural remodeling and performance. Skinned cardiac fiber bundles were used to determine the active and passive stress properties, maximum shortening velocity, and calcium sensitivity. RESULTS Aerobic training was characterized structurally by increases in ventricle volume (Ex+Standard, 19%; Ex+Pro, 29%) and myocardial thickness (Ex+Standard, 26%; Ex+- Pro, 12%) compared to that of baseline. Skinned trabecula r fiber bundles also had a greater unloaded shortening velocity (Sed+Standard, 1.04±0.05; Sed+Pro, 1.07±0.03; Ex- +Standard, 1.16±0.04; Ex+Pro, 1.18±0.05 FL/s) and calcium sensitivity (pCa50: Sed+Standard, 6.04±0.17; Sed+Pro, 6.08±0.19; Ex+Standard, 6.30±0.09; Ex+Pro, 6.36±0.12) in trained hearts compared to that of hearts from sedentary animals. However, the addition of a high-protein diet did not provide additional benefits to either the structural or mechanical adaptations of the myocardium. CONCLUSION Therefore, it seems that a high-whey-protein diet does not significantly enhance adaptations of the heart to aerobic exercise in comparison to that of a standard diet.
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Affiliation(s)
- Kevin Boldt
- Human Performance Laboratory, University of Calgary, Calgary, Canada
| | - Venus Joumaa
- Human Performance Laboratory, University of Calgary, Calgary, Canada
| | - Jeannine Turnbull
- Health Center, Federal University of Santa Catarina, Florianopolis, Brazil
| | - Paul W.M. Fedak
- Health Center, Federal University of Santa Catarina, Florianopolis, Brazil
| | - Walter Herzog
- Human Performance Laboratory, University of Calgary, Calgary, Canada
- Department of Cardiac Sciences, University of Calgary, Calgary, Canada
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Increased Expression of N2BA Titin Corresponds to More Compliant Myofibrils in Athlete's Heart. Int J Mol Sci 2021; 22:ijms222011110. [PMID: 34681770 PMCID: PMC8537917 DOI: 10.3390/ijms222011110] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 10/07/2021] [Accepted: 10/10/2021] [Indexed: 12/22/2022] Open
Abstract
Long-term exercise induces physiological cardiac adaptation, a condition referred to as athlete’s heart. Exercise tolerance is known to be associated with decreased cardiac passive stiffness. Passive stiffness of the heart muscle is determined by the giant elastic protein titin. The adult cardiac muscle contains two titin isoforms: the more compliant N2BA and the stiffer N2B. Titin-based passive stiffness may be controlled by altering the expression of the different isoforms or via post-translational modifications such as phosphorylation. Currently, there is very limited knowledge about titin’s role in cardiac adaptation during long-term exercise. Our aim was to determine the N2BA/N2B ratio and post-translational phosphorylation of titin in the left ventricle and to correlate the changes with the structure and transverse stiffness of cardiac sarcomeres in a rat model of an athlete’s heart. The athlete’s heart was induced by a 12-week-long swim-based training. In the exercised myocardium the N2BA/N2B ratio was significantly increased, Ser11878 of the PEVK domain was hypophosphorlyated, and the sarcomeric transverse elastic modulus was reduced. Thus, the reduced passive stiffness in the athlete’s heart is likely caused by a shift towards the expression of the longer cardiac titin isoform and a phosphorylation-induced softening of the PEVK domain which is manifested in a mechanical rearrangement locally, within the cardiac sarcomere.
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Boldt K, Joumaa V, Turnbull J, Fedak PWM, Herzog W. Mechanical and Structural Remodeling of Cardiac Muscle after Aerobic and Resistance Exercise Training in Rats. Med Sci Sports Exerc 2021; 53:1583-1594. [PMID: 33731663 DOI: 10.1249/mss.0000000000002625] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
INTRODUCTION Aerobic and resistance exercise training results in distinct structural changes of the heart. The mechanics of how cardiac cells adapt to resistance training and the benefits to cells when combining aerobic and resistance exercise remains largely unknown. The purpose of this study was to compare mechanical adaptations of skinned cardiac fiber bundles after chronic resistance, aerobic and combined exercise training in rats. We hypothesized that differences in mechanical function on the fiber bundle level coincide with differences previously reported in the structure of the heart. METHOD Twelve-week-old rats were assigned to (i) an aerobic running group (n = 6), (ii) a ladder climbing resistance group (n = 6), (iii) a combination group subjected to aerobic and resistance training (n = 6), or (iv) a sedentary (control) group (n = 5). Echocardiography was used to measure cardiac structural remodeling. Skinned cardiac fiber bundles were used to determine active and passive force properties, maximal shortening velocity, and calcium sensitivity. RESULTS Aerobically trained animals had 43%-49% greater ventricular volume and myocardial thickness, and a 4%-17% greater shortening velocity and calcium sensitivity compared with control group rats. Resistance-trained rats had 37%-71% thicker ventricular walls, a 56% greater isometric force production, a 9% greater shortening velocity, and a 4% greater calcium sensitivity compared with control group rats. The combination exercise-trained rats had 25%-43% greater ventricular volume and myocardial wall thickness, a 55% greater active force production, a 7% greater shortening velocity, and a 60% greater cross-bridge cooperativity compared with control group rats. CONCLUSIONS The heart adapts differently to each exercise modality, and a combination of aerobic and resistance training may have the greatest benefit for cardiac health and performance.
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Affiliation(s)
- Kevin Boldt
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, CANADA
| | - Venus Joumaa
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, CANADA
| | - Jeannine Turnbull
- Department of Cardiac Sciences, Cumming School of Medicine, University of Calgary, Libin Cardiovascular Institute, Calgary, Alberta, CANADA
| | - Paul W M Fedak
- Department of Cardiac Sciences, Cumming School of Medicine, University of Calgary, Libin Cardiovascular Institute, Calgary, Alberta, CANADA
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Boldt K, Rios JL, Joumaa V, Herzog W. Mechanical function of cardiac fibre bundles is partly protected by exercise in response to diet-induced obesity in rats. Appl Physiol Nutr Metab 2020; 46:46-54. [PMID: 32598858 DOI: 10.1139/apnm-2020-0275] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Decrements in contractile function resulting from obesity are thought to be major reasons for the link between obesity and cardiovascular disease, while exercise has been shown to improve cardiac muscle contractile function. The purpose of this study was to evaluate cardiac contractile properties following obesity induction and the potential protective effect of exercise. Twelve-week-old rats (n = 30) were organized into either a chow diet or a high-fat, high-sucrose (HFHS) diet group. Following 12 weeks of obesity induction the HFHS group animals were stratified and grouped into sedentary (HFHS+Sed) and exercise (HFHS+Ex) groups for an additional 12 weeks. Following 24 weeks of diet intervention, with 12 weeks of aerobic exercise (25 m/min, 30 min/day, 5 days/week) for the HFHS+Ex group, skinned cardiac fibre bundle testing was used to evaluate cardiac contractile properties. Body fat and mass were significantly greater in the HFHS-fed animals compared with the chow controls (p < 0.043). Hearts from rats in the HFHS+Sed group had significantly greater mass (p < 0.03), significantly slower maximum shortening velocity (p = 0.001), and tended to have lower calcium sensitivity (p = 0.077) and a lower proportion of α-myosin heavy chain composition (p = 0.074) than the sedentary chow animals. However, 12 weeks of moderate aerobic exercise partially prevented these decrements in contractile properties. Novelty Cardiac muscle from animals exposed to an obesogenic diet for 24 weeks had impaired contractile properties compared with controls. Obesity-induced impairment of contractile properties of the heart were partially prevented by a 12-week aerobic exercise regime.
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Affiliation(s)
- Kevin Boldt
- Faculty of Kinesiology, University of Calgary, Calgary, AB T2N 1N4, Canada.,Human Performance Laboratory, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Jaqueline Lourdes Rios
- Faculty of Kinesiology, University of Calgary, Calgary, AB T2N 1N4, Canada.,Human Performance Laboratory, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Venus Joumaa
- Faculty of Kinesiology, University of Calgary, Calgary, AB T2N 1N4, Canada.,Human Performance Laboratory, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Walter Herzog
- Faculty of Kinesiology, University of Calgary, Calgary, AB T2N 1N4, Canada.,Human Performance Laboratory, University of Calgary, Calgary, AB T2N 1N4, Canada.,Biomechanics Laboratory, School of Sports, Federal University of Santa Catarina, SC 88040-900, Brazil
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Danielsson T, Carlsson J, Siethoff LT, Ahnesjö J, Bergman P. Aerobic capacity predict skeletal but not cardiac muscle damage after triathlon - the Iron(WO)man study. Sci Rep 2020; 10:901. [PMID: 31965015 PMCID: PMC6972947 DOI: 10.1038/s41598-020-57842-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Accepted: 01/08/2020] [Indexed: 11/29/2022] Open
Abstract
This study examines the association between aerobic capacity and biomarkers of skeletal- and cardiac muscle damage among amateur triathletes after a full distance Ironman. Men and women (N = 55) were recruited from local sport clubs. One month before an Ironman triathlon, they conducted a 20 m shuttle run test to determine aerobic capacity. Blood samples were taken immediately after finishing the triathlon, and analyzed for cardiac Troponin T (cTnT), Myosin heavy chain-a (MHC-a), N-terminal prohormone of brain natriuretic peptide (NT-proBNP), Creatin Kinas (CK), and Myoglobin. Regression models examining the association between the biomarkers and aerobic capacity expressed in both relative terms (mLO2*kg−1*min−1) and absolute terms (LO2*min−1) controlled for weight were fitted. A total of 39 subjects (26% females) had complete data and were included in the analysis. No association between aerobic capacity and cardiac muscle damage was observed. For myoglobin, adding aerobic capacity (mLO2*kg−1*min−1) increased the adjusted r2 from 0.026 to 0.210 (F: 8.927, p = 0.005) and for CK the adjusted r2 increased from -0.015 to 0.267 (F: 13.778, p = 0.001). In the models where aerobic capacity was entered in absolute terms the adjusted r2 increased from 0.07 to 0.227 (F: 10.386, p = 0.003) for myoglobin and for CK from -0.029 to 0.281 (F: 15.215, p < 0.001). A negative association between aerobic capacity and skeletal muscle damage was seen but despite the well-known cardio-protective health effect of high aerobic fitness, no such association could be observed in this study.
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Affiliation(s)
- Tom Danielsson
- Department of Sport Sciences Linnaeus University, Kalmar, Sweden
| | - Jörg Carlsson
- Department of Health Sciences Linnaeus University, Kalmar, Sweden.,Department for Medicine, Section of Cardiology, Kalmar County Hospital, Kalmar, Sweden
| | - Lasse Ten Siethoff
- Department of Sport Sciences Linnaeus University, Kalmar, Sweden.,The Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Jonas Ahnesjö
- Department of Sport Sciences Linnaeus University, Kalmar, Sweden
| | - Patrick Bergman
- Department of Sport Sciences Linnaeus University, Kalmar, Sweden. .,eHealth institute, Department of Medicine and Optometry, Linnaeus University, Kalmar, Sweden.
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Gholamnezhad Z, Mégarbane B, Rezaee R. Molecular Mechanisms Mediating Adaptation to Exercise. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1228:45-61. [PMID: 32342449 DOI: 10.1007/978-981-15-1792-1_3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Several experimental and human studies documented the preventive and therapeutic effects of exercise on the normal physiological function of different body systems during aging as well as various diseases. Recent studies using cellular and molecular (biochemical, proteomics, and genomics) techniques indicated that exercise modifies intracellular and extracellular signaling and pathways. In addition, in vivo or in vitro experiments, particularly, using knockout and transgenic animals, helped to mimic physiological conditions during and after exercise. According to the findings of these studies, some important signaling pathways modulated by exercise are Ca2+-dependent calcineurin/activated nuclear factor of activated T-cells, mammalian target of rapamycin, myostatin/Smad, and AMP-activated protein kinase regulation of peroxisome proliferator-activated receptor-gamma coactivator 1-alpha. Such modulations contribute to cell adaptation and remodeling of muscle fiber type in response to exercise. Despite great improvement in this field, there are still several unanswered questions as well as unfixed issues concerning clinical trials' biases and limitations. Nevertheless, designing multicenter standard clinical trials while considering individual variability and the exercise modality and duration will improve the perspective we have on the mechanisms mediating adaptation to exercise and final outcomes.
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Affiliation(s)
- Zahra Gholamnezhad
- Neurogenic Inflammation Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
- Department of Physiology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
| | - Bruno Mégarbane
- Department of Medical and Toxicological Critical Care, Paris-Diderot University, Paris, France
| | - Ramin Rezaee
- Clinical Research Unit, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
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Boldt KR, Rios JL, Joumaa V, Herzog W. Force properties of skinned cardiac muscle following increasing volumes of aerobic exercise in rats. J Appl Physiol (1985) 2018; 125:495-503. [PMID: 29722623 PMCID: PMC6139514 DOI: 10.1152/japplphysiol.00631.2017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 04/19/2018] [Accepted: 04/30/2018] [Indexed: 11/22/2022] Open
Abstract
The positive effects of chronic endurance exercise training on health and performance have been well documented. These positive effects have been evaluated primarily at the structural level, and work has begun to evaluate mechanical adaptations of the myocardium. However, it remains poorly understood how the volume of exercise training affects cardiac adaptation. To gain some understanding, we subjected 3-mo-old Sprague-Dawley rats ( n = 23) to treadmill running for 11 wk at one of three exercise volumes (moderate, high, and extra high). Following training, hearts were excised and mechanical testing was completed on skinned trabecular fiber bundles. Performance on a maximal fitness test was dose dependent on training volume, where greater levels of training led to greater performance. No differences were observed between animals from any group for maximal active stress and passive stress at a sarcomere length of 2.2 µm. Heart mass and passive stress at sarcomere lengths beyond 2.4 µm increased in a dose-dependent manner for animals in the control and moderate- and high-duration groups. However, hearts from animals in the extra high-duration group presented with inhibited responses for heart mass and passive stress, despite performing greatest on a graded treadmill fitness test. These results suggest that heart mass and passive stress adapt in a dose-dependent manner, until exercise becomes excessive and adaptation is inhibited. Our findings are in agreement with the beneficial role exercise has in cardiac adaptation. However, excessive exercise comes with risks of maladaptation, which must be weighed against the desire to increase performance. NEW & NOTEWORTHY For the first time, we present findings on cardiac trabecular muscle passive stiffness and show the effect of excessive exercise on the heart. We demonstrated that heart mass increases with exercise until a maximum, after which greater exercise volume results in inhibited adaptation. At paraphysiological lengths, passive stiffness increases with exercise but to a lesser degree with excessive training. Despite greater performance on graded exercise tests, animals in the highest trained group exhibited possible maladaptation.
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Affiliation(s)
- Kevin R Boldt
- Human Performance Laboratory, University of Calgary , Calgary, Alberta , Canada
- Faculty of Kinesiology, University of Calgary , Calgary, Alberta , Canada
| | - Jaqueline L Rios
- Human Performance Laboratory, University of Calgary , Calgary, Alberta , Canada
- Faculty of Kinesiology, University of Calgary , Calgary, Alberta , Canada
| | - Venus Joumaa
- Human Performance Laboratory, University of Calgary , Calgary, Alberta , Canada
- Faculty of Kinesiology, University of Calgary , Calgary, Alberta , Canada
| | - Walter Herzog
- Human Performance Laboratory, University of Calgary , Calgary, Alberta , Canada
- Faculty of Kinesiology, University of Calgary , Calgary, Alberta , Canada
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10
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Patel JR, Barton GP, Braun RK, Goss KN, Haraldsdottir K, Hopp A, Diffee G, Hacker TA, Moss RL, Eldridge MW. Altered Right Ventricular Mechanical Properties Are Afterload Dependent in a Rodent Model of Bronchopulmonary Dysplasia. Front Physiol 2017; 8:840. [PMID: 29118720 PMCID: PMC5660986 DOI: 10.3389/fphys.2017.00840] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 10/09/2017] [Indexed: 02/02/2023] Open
Abstract
Infants born premature are at increased risk for development of bronchopulmonary dysplasia (BPD), pulmonary hypertension (PH), and ultimately right ventricular (RV) dysfunction, which together carry a high risk of neonatal mortality. However, the role alveolar simplification and abnormal pulmonary microvascular development in BPD affects RV contractile properties is unknown. We used a rat model of BPD to examine the effect of hyperoxia-induced PH on RV contractile properties. We measured in vivo RV pressure as well as passive force, maximum Ca2+ activated force, calcium sensitivity of force (pCa50) and rate of force redevelopment (ktr) in RV skinned trabeculae isolated from hearts of 21-and 35-day old rats pre-exposed to 21% oxygen (normoxia) or 85% oxygen (hyperoxia) for 14 days after birth. Systolic and diastolic RV pressure were significantly higher at day 21 in hyperoxia exposed rats compared to normoxia control rats, but normalized by 35 days of age. Passive force, maximum Ca2+ activated force, and calcium sensitivity of force were elevated and cross-bridge cycling kinetics depressed in 21-day old hyperoxic trabeculae, whereas no differences between normoxic and hyperoxic trabeculae were seen at 35 days. Myofibrillar protein analysis revealed that 21-day old hyperoxic trabeculae had increased levels of beta-myosin heavy chain (β-MHC), atrial myosin light chain 1 (aMLC1; often referred to as essential light chain), and slow skeletal troponin I (ssTnI) compared to age matched normoxic trabeculae. On the other hand, 35-day old normoxic and hyperoxic trabeculae expressed similar level of α- and β-MHC, ventricular MLC1 and predominantly cTnI. These results suggest that neonatal exposure to hyperoxia increases RV afterload and affect both the steady state and dynamic contractile properties of the RV, likely as a result of hyperoxia-induced expression of β-MHC, delayed transition of slow skeletal TnI to cardiac TnI, and expression of atrial MLC1. These hyperoxia-induced changes in contractile properties are reversible and accompany the resolution of PH with further developmental age, underscoring the importance of reducing RV afterload to allow for normalization of RV function in both animal models and humans with BPD.
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Affiliation(s)
- Jitandrakumar R Patel
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI, United States
| | - Gregory P Barton
- Department of Pediatrics, University of Wisconsin-Madison, Madison, WI, United States
| | - Rudolf K Braun
- Department of Pediatrics, University of Wisconsin-Madison, Madison, WI, United States
| | - Kara N Goss
- Department of Pediatrics, University of Wisconsin-Madison, Madison, WI, United States
| | - Kristin Haraldsdottir
- Department of Pediatrics, University of Wisconsin-Madison, Madison, WI, United States.,Department of Kinesiology, University of Wisconsin-Madison, Madison, WI, United States
| | - Alexandria Hopp
- Department of Pediatrics, University of Wisconsin-Madison, Madison, WI, United States.,Department of Kinesiology, University of Wisconsin-Madison, Madison, WI, United States
| | - Gary Diffee
- Department of Kinesiology, University of Wisconsin-Madison, Madison, WI, United States
| | - Timothy A Hacker
- Cardiovascular Research Center, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Richard L Moss
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI, United States
| | - Marlowe W Eldridge
- Department of Pediatrics, University of Wisconsin-Madison, Madison, WI, United States.,Department of Kinesiology, University of Wisconsin-Madison, Madison, WI, United States.,Cardiovascular Research Center, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
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da Silva VL, Lima-Leopoldo AP, Ferron AJT, Cordeiro JP, Freire PP, de Campos DHS, Padovani CR, Sugizaki MM, Cicogna AC, Leopoldo AS. Moderate exercise training does not prevent the reduction in myocardial L-type Ca 2+ channels protein expression at obese rats. Physiol Rep 2017; 5:5/19/e13466. [PMID: 29038363 PMCID: PMC5641941 DOI: 10.14814/phy2.13466] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 09/01/2017] [Accepted: 09/04/2017] [Indexed: 01/08/2023] Open
Abstract
Authors have showed that obesity implicates cardiac dysfunction associated with myocardial L-type calcium channels (LTCCs) activity impairments, as well as moderate exercise training (MET) seems to be an important therapeutic tool. We tested the hypothesis that MET promotes improvements on LTCCS activity and protein expression at obesity induced by unsaturated high-fat diets, which could represent a protective effects against development of cardiovascular damage. Male Wistar rats were randomized in control (C, n = 40), which received a standard diet and obese (Ob; n = 40), which received high-fat diet. After 20 weeks, the animals were assigned at four groups: control (C; n = 12); control submitted to exercise training (ET; n = 14); obese (Ob; n = 10); and obese submitted to exercise training (ObET; n = 11). ET (5 days/week during 12 weeks) began in the 21th week and consisted of treadmill running that was progressively increased to reach 60 min. Final body weight (FBW), body fat (BF), adiposity index (AI), comorbidities, and hormones were evaluated. Cardiac remodeling was assessed by morphological and isolated papillary muscles function. LTCCs activity was determined using specific blocker, while protein expression of LTCCs was evaluated by Western blot. Unsaturated high-fat diet promoted obesity during all experimental protocol. MET controlled obesity process by decreasing of FBW, BF, and AI. Obesity implicated to LTCCs protein expression reduction and MET was not effective to prevent this condition. ET was efficient to promote several improvements to body composition and metabolic parameters; however, it was not able to prevent or reverse the downregulation of LTCCs protein expression at obese rats.
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Affiliation(s)
- Vitor L da Silva
- Department of Internal Medicine, São Paulo State University, Botucatu, Brazil
| | - Ana P Lima-Leopoldo
- Center of Physical Education and Sports, Department of Sports, Federal University of Espírito Santo, Vitória, Brazil
| | - Artur J T Ferron
- Department of Internal Medicine, São Paulo State University, Botucatu, Brazil
| | - Jóctan P Cordeiro
- Center of Physical Education and Sports, Department of Sports, Federal University of Espírito Santo, Vitória, Brazil
| | - Paula P Freire
- Department of Morphology, São Paulo State University, Botucatu, Brazil
| | - Dijon H S de Campos
- Department of Internal Medicine, São Paulo State University, Botucatu, Brazil
| | - Carlos R Padovani
- Department of Biostatistics, Institute of Biosciences, São Paulo State University, Botucatu, Brazil
| | - Mário M Sugizaki
- Institute of Health Science, Federal University of Mato Grosso, Sinop, Brazil
| | - Antonio C Cicogna
- Department of Internal Medicine, São Paulo State University, Botucatu, Brazil
| | - André S Leopoldo
- Center of Physical Education and Sports, Department of Sports, Federal University of Espírito Santo, Vitória, Brazil
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Exercise Training and Epigenetic Regulation: Multilevel Modification and Regulation of Gene Expression. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1000:281-322. [PMID: 29098627 DOI: 10.1007/978-981-10-4304-8_16] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Exercise training elicits acute and adaptive long term changes in human physiology that mediate the improvement of performance and health state. The responses are integrative and orchestrated by several mechanisms, as gene expression. Gene expression is essential to construct the adaptation of the biological system to exercise training, since there are molecular processes mediating oxidative and non-oxidative metabolism, angiogenesis, cardiac and skeletal myofiber hypertrophy, and other processes that leads to a greater physiological status. Epigenetic is the field that studies about gene expression changes heritable by meiosis and mitosis, by changes in chromatin and DNA conformation, but not in DNA sequence, that studies the regulation on gene expression that is independent of genotype. The field approaches mechanisms of DNA and chromatin conformational changes that inhibit or increase gene expression and determine tissue specific pattern. The three major studied epigenetic mechanisms are DNA methylation, Histone modification, and regulation of noncoding RNA-associated genes. This review elucidates these mechanisms, focusing on the relationship between them and their relationship with exercise training, physical performance and the enhancement of health status. On this chapter, we clarified the relationship of epigenetic modulations and their intimal relationship with acute and chronic effect of exercise training, concentrating our effort on skeletal muscle, heart and vascular responses, that are the most responsive systems against to exercise training and play crucial role on physical performance and improvement of health state.
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High molecular mass proteomics analyses of left ventricle from rats subjected to differential swimming training. BMC PHYSIOLOGY 2012; 12:11. [PMID: 22950628 PMCID: PMC3508799 DOI: 10.1186/1472-6793-12-11] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2011] [Accepted: 08/28/2012] [Indexed: 11/10/2022]
Abstract
BACKGROUND Regular exercises are commonly described as an important factor in health improvement, being directly related to contractile force development in cardiac cells.In order to evaluate the links between swimming exercise intensity and cardiac adaptation by using high molecular mass proteomics, isogenic Wistar rats were divided into four groups: one control (CG) and three training groups (TG's), with low, moderate and high intensity of exercises.In order to evaluate the links between swimming exercise intensity and cardiac adaptation by using high molecular mass proteomics, isogenic Wistar rats were divided into four groups: one control (CG) and three training groups (TG's), with low, moderate and high intensity of exercises. RESULTS Findings here reported demonstrated clear morphologic alterations, significant cellular injury and increased energy supplies at high exercise intensities. α-MyHC, as well proteins associated with mitochondrial oxidative metabolism were shown to be improved. α-MyHC expression increase 1.2 fold in high intensity training group when compared with control group. α-MyHC was also evaluated by real-time PCR showing a clear expression correlation with protein synthesis data increase in 8.48 fold in high intensity training group. Other myofibrillar protein, troponin , appear only in high intensity group, corroborating the cellular injury data. High molecular masses proteins such as MRS2 and NADH dehydrogenase, involved in metabolic pathways also demonstrate increase expression, respectily 1.5 and 1.3 fold, in response to high intensity exercise. CONCLUSIONS High intensity exercise demonstrated an increase expression in some high molecular masses myofibrilar proteins, α-MyHC and troponin. Furthermore this intensity also lead a significant increase of other high molecular masses proteins such as MRS2 and NADH dehydrogenase in comparison to low and moderate intensities. However, high intensity exercise also represented a significant degree of cellular injury, when compared with the individuals submitted to low and moderate intensities.
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Petriz BA, Gomes CP, Rocha LAO, Rezende TMB, Franco OL. Proteomics applied to exercise physiology: A cutting-edge technology. J Cell Physiol 2011; 227:885-98. [DOI: 10.1002/jcp.22809] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Ericsson M, Sjåland C, Andersson KB, Sjaastad I, Christensen G, Sejersted OM, Ellingsen Ø. Exercise training before cardiac-specific Serca2 disruption attenuates the decline in cardiac function in mice. J Appl Physiol (1985) 2010; 109:1749-55. [DOI: 10.1152/japplphysiol.00282.2010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In the heart, function of the sarco(endo)plasmic Ca2+-ATPase (SERCA2) is closely linked to contractility, cardiac function, and aerobic fitness. SERCA2 function can be increased by high-intensity interval training, whereas reduced SERCA2 abundance is associated with impaired cardiac function. The working hypothesis was, therefore, that exercise training before cardiomyocyte-specific disruption of the Serca2 gene would delay the onset of cardiac dysfunction in mice. Before Serca2 gene disruption by tamoxifen, untreated SERCA2 knockout mice ( Serca2flox/flox Tg-αMHC-MerCreMer; S2KO), and SERCA2 FF control mice ( Serca2flox/flox, S2FF) were exercise trained by high-intensity interval treadmill running for 6 wk. Both genotypes responded to training, with comparable increases in maximal oxygen uptake (V̇o2max; 17%), left ventricle weight (15%), and maximal running speed (40%). After exercise training, cardiac-specific Serca2 gene disruption was induced in both exercise trained and sedentary S2KO mice. In trained S2KO, cardiac function decreased less rapidly than in sedentary S2KO. V̇o2max remained higher in trained S2KO the first 15 days after gene disruption. Six weeks after Serca2 disruption, cardiac output was higher in trained compared with sedentary S2KO mice. An exercise-training program attenuates the decline in cardiac performance induced by acute cardiac Serca2 gene disruption, indicating that mechanisms other than SERCA2 contribute to the favorable effect of exercise training.
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Affiliation(s)
- Madelene Ericsson
- Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim
| | - Cecilie Sjåland
- Institute for Experimental Medical Research, Oslo University Hospital Ullevaal, Oslo
- Center for Heart Failure Research, University of Oslo; and
| | - Kristin B. Andersson
- Institute for Experimental Medical Research, Oslo University Hospital Ullevaal, Oslo
- Center for Heart Failure Research, University of Oslo; and
| | - Ivar Sjaastad
- Institute for Experimental Medical Research, Oslo University Hospital Ullevaal, Oslo
- Center for Heart Failure Research, University of Oslo; and
| | - Geir Christensen
- Institute for Experimental Medical Research, Oslo University Hospital Ullevaal, Oslo
- Center for Heart Failure Research, University of Oslo; and
| | - Ole M. Sejersted
- Institute for Experimental Medical Research, Oslo University Hospital Ullevaal, Oslo
- Center for Heart Failure Research, University of Oslo; and
| | - Øyvind Ellingsen
- Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim
- Department of Cardiology, St. Olavs Hospital, Trondheim, Norway
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Bocalini DS, Carvalho EVA, de Sousa AFM, Levy RF, Tucci PJF. Exercise training-induced enhancement in myocardial mechanics is lost after 2 weeks of detraining in rats. Eur J Appl Physiol 2010; 109:909-14. [DOI: 10.1007/s00421-010-1406-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/15/2010] [Indexed: 10/19/2022]
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Shao CH, Wehrens XHT, Wyatt TA, Parbhu S, Rozanski GJ, Patel KP, Bidasee KR. Exercise training during diabetes attenuates cardiac ryanodine receptor dysregulation. J Appl Physiol (1985) 2009; 106:1280-92. [PMID: 19131475 DOI: 10.1152/japplphysiol.91280.2008] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The present study was undertaken to assess the effects of exercise training (ExT) initiated after the onset of diabetes on cardiac ryanodine receptor expression and function. Type 1 diabetes was induced in male Sprague-Dawley rats using streptozotocin (STZ). Three weeks after STZ injection, diabetic rats were divided into two groups. One group underwent ExT for 4 wk while the other group remained sedentary. After 7 wk of sedentary diabetes, cardiac fractional shortening, rate of rise of left ventricular pressure, and myocyte contractile velocity were reduced by 14, 36, 44%, respectively. Spontaneous Ca(2+) spark frequency increased threefold, and evoked Ca(2+) release was dyssynchronous with diastolic Ca(2+) releases. Steady-state type 2 ryanodine receptor (RyR2) protein did not change, but its response to Ca(2+) was altered. RyR2 also exhibited 1.8- and 1.5-fold increases in phosphorylation at Ser(2808) and Ser(2814). PKA activity was reduced by 75%, but CaMKII activity was increased by 50%. Four weeks of ExT initiated 3 wk after the onset of diabetes blunted decreases in cardiac fractional shortening and rate of left ventricular pressure development, increased the responsiveness of the myocardium to isoproterenol stimulation, attenuated the increase in Ca(2+) spark frequency, and minimized dyssynchronous and diastolic Ca(2+) releases. ExT also normalized the responsiveness of RyR2 to Ca(2+) activation, attenuated increases in RyR2 phosphorylation at Ser(2808) and Ser(2814), and normalized CaMKII and PKA activities. These data are the first to show that ExT during diabetes normalizes RyR2 function and Ca(2+) release from the sarcoplasmic reticulum, providing insights into mechanisms by which ExT during diabetes improves cardiac function.
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Affiliation(s)
- Chun-Hong Shao
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
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Wang S, Ma JZ, Zhu SS, Xu DJ, Zou JG, Cao KJ. Swimming training can affect intrinsic calcium current characteristics in rat myocardium. Eur J Appl Physiol 2008; 104:549-55. [DOI: 10.1007/s00421-008-0803-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/09/2008] [Indexed: 10/21/2022]
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Modulation of Murf-1 and MAFbx expression in the myocardium by physical exercise training. ACTA ACUST UNITED AC 2008; 15:293-9. [DOI: 10.1097/hjr.0b013e3282f3ec43] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Sun B, Wang JH, Lv YY, Zhu SS, Yang J, Ma JZ. Proteomic adaptation to chronic high intensity swimming training in the rat heart. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2008; 3:108-17. [DOI: 10.1016/j.cbd.2007.11.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2007] [Revised: 11/23/2007] [Accepted: 11/23/2007] [Indexed: 01/07/2023]
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