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Lund J, Hafstad AD, Boardman NT, Rossvoll L, Rolim NP, Ahmed MS, Florholmen G, Attramadal H, Wisløff U, Larsen TS, Aasum E. Exercise training promotes cardioprotection through oxygen-sparing action in high fat-fed mice. Am J Physiol Heart Circ Physiol 2015; 308:H823-9. [PMID: 25637547 DOI: 10.1152/ajpheart.00734.2014] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 01/28/2015] [Indexed: 11/22/2022]
Abstract
Although exercise training has been demonstrated to have beneficial cardiovascular effects in diabetes, the effect of exercise training on hearts from obese/diabetic models is unclear. In the present study, mice were fed a high-fat diet, which led to obesity, reduced aerobic capacity, development of mild diastolic dysfunction, and impaired glucose tolerance. Following 8 wk on high-fat diet, mice were assigned to 5 weekly high-intensity interval training (HIT) sessions (10 × 4 min at 85-90% of maximum oxygen uptake) or remained sedentary for the next 10 constitutive weeks. HIT increased maximum oxygen uptake by 13%, reduced body weight by 16%, and improved systemic glucose homeostasis. Exercise training was found to normalize diastolic function, attenuate diet-induced changes in myocardial substrate utilization, and dampen cardiac reactive oxygen species content and fibrosis. These changes were accompanied by normalization of obesity-related impairment of mechanical efficiency due to a decrease in work-independent myocardial oxygen consumption. Finally, we found HIT to reduce infarct size by 47% in ex vivo hearts subjected to ischemia-reperfusion. This study therefore demonstrated for the first time that exercise training mediates cardioprotection following ischemia in diet-induced obese mice and that this was associated with oxygen-sparing effects. These findings highlight the importance of optimal myocardial energetics during ischemic stress.
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Affiliation(s)
- J Lund
- Cardiovascular Research Group, Department of Medical Biology, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway;
| | - A D Hafstad
- Cardiovascular Research Group, Department of Medical Biology, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - N T Boardman
- Cardiovascular Research Group, Department of Medical Biology, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - L Rossvoll
- Cardiovascular Research Group, Department of Medical Biology, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - N P Rolim
- K. G. Jebsen Center of Exercise in Medicine, Department of Circulation and Medical Imaging, Faculty of Medicine, Norwegian University of Science and Technology and Saint Olavs Hospital, Trondheim University Hospital, Trondheim, Norway; and
| | - M S Ahmed
- Institute for Surgical Research, Department of Cardiology, Center for Heart Failure Research, Oslo University Hospital-Rikshospitalet, University of Oslo, Oslo, Norway
| | - G Florholmen
- Institute for Surgical Research, Department of Cardiology, Center for Heart Failure Research, Oslo University Hospital-Rikshospitalet, University of Oslo, Oslo, Norway
| | - H Attramadal
- Institute for Surgical Research, Department of Cardiology, Center for Heart Failure Research, Oslo University Hospital-Rikshospitalet, University of Oslo, Oslo, Norway
| | - U Wisløff
- K. G. Jebsen Center of Exercise in Medicine, Department of Circulation and Medical Imaging, Faculty of Medicine, Norwegian University of Science and Technology and Saint Olavs Hospital, Trondheim University Hospital, Trondheim, Norway; and
| | - T S Larsen
- Cardiovascular Research Group, Department of Medical Biology, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - E Aasum
- Cardiovascular Research Group, Department of Medical Biology, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
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Hafstad AD, Boardman NT, Lund J, Hagve M, Khalid AM, Wisløff U, Larsen TS, Aasum E. High intensity interval training alters substrate utilization and reduces oxygen consumption in the heart. J Appl Physiol (1985) 2011; 111:1235-41. [PMID: 21836050 DOI: 10.1152/japplphysiol.00594.2011] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
AIMS although exercise training induces hypertrophy with improved contractile function, the effect of exercise on myocardial substrate metabolism and cardiac efficiency is less clear. High intensity training has been shown to produce more profound effects on cardiovascular function and aerobic capacity than isocaloric low and moderate intensity training. The aim of the present study was to explore metabolic and mechanoenergetic changes in the heart following endurance exercise training of both high and moderate intensity. METHODS AND RESULTS C57BL/6J mice were subjected to 10 wk treadmill running, either high intensity interval training (HIT) or distance-matched moderate intensity training (MIT), where HIT led to a pronounced increase in maximal oxygen uptake. Although both modes of exercise were associated with a 10% increase in heart weight-to-body weight ratio, only HIT altered cardiac substrate utilization, as revealed by a 36% increase in glucose oxidation and a concomitant reduction in fatty acid oxidation. HIT also improved cardiac efficiency by decreasing work-independent myocardial oxygen consumption. In addition, it increased cardiac maximal mitochondrial respiratory capacity. CONCLUSION This study shows that high intensity training is required for induction of changes in cardiac substrate utilization and energetics, which may contribute to the superior effects of high compared with moderate intensity training in terms of increasing aerobic capacity.
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Affiliation(s)
- A D Hafstad
- Cardiovascular Research Group, Institute of Medical Biology, Faculty of Health Sciences, Univ. of Tromsø, N-9037 Tromsø, Norway.
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How OJ, Larsen TS, Hafstad AD, Khalid A, Myhre ESP, Murray AJ, Boardman NT, Cole M, Clarke K, Severson DL, Aasum E. Rosiglitazone treatment improves cardiac efficiency in hearts from diabetic mice. Arch Physiol Biochem 2007; 113:211-20. [PMID: 18158644 DOI: 10.1080/13813450701783281] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Isolated perfused hearts from type 2 diabetic (db/db) mice show impaired ventricular function, as well as altered cardiac metabolism. Assessment of the relationship between myocardial oxygen consumption (MVO(2)) and ventricular pressure-volume area (PVA) has also demonstrated reduced cardiac efficiency in db/db hearts. We hypothesized that lowering the plasma fatty acid supply and subsequent normalization of altered cardiac metabolism by chronic treatment with a peroxisome proliferator-activated receptor-gamma (PPARgamma) agonist will improve cardiac efficiency in db/db hearts. Rosiglitazone (23 mg/kg body weight/day) was administered as a food admixture to db/db mice for five weeks. Ventricular function and PVA were assessed using a miniaturized (1.4 Fr) pressure-volume catheter; MVO(2) was measured using a fibre-optic oxygen sensor. Chronic rosiglitazone treatment of db/db mice normalized plasma glucose and lipid concentrations, restored rates of cardiac glucose and fatty acid oxidation, and improved cardiac efficiency. The improved cardiac efficiency was due to a significant decrease in unloaded MVO(2), while contractile efficiency was unchanged. Rosiglitazone treatment also improved functional recovery after low-flow ischemia. In conclusion, the present study demonstrates that in vivo PPARgamma-treatment restores cardiac efficiency and improves ventricular function in perfused hearts from type 2 diabetic mice.
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Affiliation(s)
- O-J How
- Department of Medical Physiology, Institute of Medical Biology, Faculty of Medicine, University of Tromsø, Norway.
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