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Trager LE, Lyons M, Kuznetsov A, Sheffield C, Roh K, Freeman R, Rhee J, Guseh JS, Li H, Rosenzweig A. Beyond cardiomyocytes: Cellular diversity in the heart's response to exercise. JOURNAL OF SPORT AND HEALTH SCIENCE 2022:S2095-2546(22)00125-9. [PMID: 36549585 PMCID: PMC10362490 DOI: 10.1016/j.jshs.2022.12.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 10/24/2022] [Accepted: 11/07/2022] [Indexed: 06/17/2023]
Abstract
Cardiomyocytes comprise ∼70% to 85% of the total volume of the adult mammalian heart but only about 25% to 35% of its total number of cells. Advances in single cell and single nuclei RNA sequencing have greatly facilitated investigation into and increased appreciation of the potential functions of non-cardiomyocytes in the heart. While much of this work has focused on the relationship between non-cardiomyocytes, disease, and the heart's response to pathological stress, it will also be important to understand the roles that these cells play in the healthy heart, cardiac homeostasis, and the response to physiological stress such as exercise. The present review summarizes recent research highlighting dynamic changes in non-cardiomyocytes in response to the physiological stress of exercise. Of particular interest are changes in fibrotic pathways, the cardiac vasculature, and immune or inflammatory cells. In many instances, limited data are available about how specific lineages change in response to exercise or whether the changes observed are functionally important, underscoring the need for further research.
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Affiliation(s)
- Lena E Trager
- Corrigan Minehan Heart Center, Division of Cardiology, Cardiovascular Research Center, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; University of Minnesota Medical School, Minneapolis, MI 55455, USA
| | - Margaret Lyons
- Corrigan Minehan Heart Center, Division of Cardiology, Cardiovascular Research Center, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Alexandra Kuznetsov
- Corrigan Minehan Heart Center, Division of Cardiology, Cardiovascular Research Center, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Cedric Sheffield
- Corrigan Minehan Heart Center, Division of Cardiology, Cardiovascular Research Center, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Kangsan Roh
- Corrigan Minehan Heart Center, Division of Cardiology, Cardiovascular Research Center, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; Department of Anesthesiology and Critical Care, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Rebecca Freeman
- Corrigan Minehan Heart Center, Division of Cardiology, Cardiovascular Research Center, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - James Rhee
- Corrigan Minehan Heart Center, Division of Cardiology, Cardiovascular Research Center, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; Department of Anesthesiology and Critical Care, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - J Sawalla Guseh
- Corrigan Minehan Heart Center, Division of Cardiology, Cardiovascular Research Center, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Haobo Li
- Corrigan Minehan Heart Center, Division of Cardiology, Cardiovascular Research Center, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Anthony Rosenzweig
- Corrigan Minehan Heart Center, Division of Cardiology, Cardiovascular Research Center, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; Institute for Heart and Brain Health, University of Michigan Medical Center, Ann Arbor, MI 48109, USA.
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2
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Jia D, Hou L, Lv Y, Xi L, Tian Z. Postinfarction exercise training alleviates cardiac dysfunction and adverse remodeling via mitochondrial biogenesis and SIRT1/PGC-1α/PI3K/Akt signaling. J Cell Physiol 2019; 234:23705-23718. [PMID: 31187505 DOI: 10.1002/jcp.28939] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 05/22/2019] [Accepted: 05/23/2019] [Indexed: 12/12/2022]
Abstract
Exercise training mitigates cardiac pathological remodeling and dysfunction caused by myocardial infarction (MI), but its underlying cellular and molecular mechanisms remain elusive. Our present study in an in vivo rat model of MI determined the impact of post-MI exercise training on myocardial fibrosis, mitochondrial biogenesis, antioxidant capacity, and ventricular function. Adult male rats were randomized into: (a) Sedentary control group; (b) 4-week treadmill exercise training group; (c) Sham surgery group; (d) MI group with permanent ligation of left anterior descending coronary artery and kept sedentary during post-MI period; and (e) post-MI 4-week exercise training group. Results indicated that exercise training significantly improved post-MI left ventricular function and reduced markers of cardiac fibrosis. Exercise training also significantly attenuated MI-induced mitochondrial damage and oxidative stress, which were associated with enhanced antioxidant enzyme expression and/or activity and total antioxidant capacity in the heart. Interestingly, the adaptive activation of the SIRT1/PGC-1α/PI3K/Akt signaling following MI was further enhanced by post-MI exercise training, which is likely responsible for exercise-induced cardioprotection and mitochondrial biogenesis. In conclusion, this study has provided novel evidence on the activation of SIRT1/PGC-1α/PI3K/Akt pathway, which may mediate exercise-induced cardioprotection through reduction of cardiac fibrosis and oxidative stress, as well as improvement of mitochondrial integrity and biogenesis in post-MI myocardium.
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Affiliation(s)
- Dandan Jia
- Institute of Sports and Exercise Biology, School of Physical Education, Shaanxi Normal University, Xi'an, Shaanxi, China
| | - Lu Hou
- Institute of Sports and Exercise Biology, School of Physical Education, Shaanxi Normal University, Xi'an, Shaanxi, China
| | - Yongzhi Lv
- Institute of Sports and Exercise Biology, School of Physical Education, Shaanxi Normal University, Xi'an, Shaanxi, China
| | - Lei Xi
- Department of Internal Medicine, Pauley Heart Center, Virginia Commonwealth University, Richmond, Virginia
| | - Zhenjun Tian
- Institute of Sports and Exercise Biology, School of Physical Education, Shaanxi Normal University, Xi'an, Shaanxi, China
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3
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Toba H, Lindsey ML. Extracellular matrix roles in cardiorenal fibrosis: Potential therapeutic targets for CVD and CKD in the elderly. Pharmacol Ther 2019; 193:99-120. [PMID: 30149103 PMCID: PMC6309764 DOI: 10.1016/j.pharmthera.2018.08.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Whereas hypertension, diabetes, and dyslipidemia are age-related risk factors for cardiovascular disease (CVD) and chronic kidney disease (CKD), aging alone is an independent risk factor. With advancing age, the heart and kidney gradually but significantly undergo inflammation and subsequent fibrosis, which eventually results in an irreversible decline in organ physiology. Through cardiorenal network interactions, cardiac dysfunction leads to and responds to renal injury, and both facilitate aging effects. Thus, a comprehensive strategy is needed to evaluate the cardiorenal aging network. Common hallmarks shared across systems include extracellular matrix (ECM) accumulation, along with upregulation of matrix metalloproteinases (MMPs) including MMP-9. The wide range of MMP-9 substrates, including ECM components and inflammatory cytokines, implicates MMP-9 in a variety of pathological and age-related processes. In particular, there is strong evidence that inflammatory cell-derived MMP-9 exacerbates cardiorenal aging. This review explores the potential therapeutic targets against CVD and CKD in the elderly, focusing on ECM and MMP roles.
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Affiliation(s)
- Hiroe Toba
- Department of Clinical Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto, Japan.
| | - Merry L Lindsey
- Mississippi Center for Heart Research, Department of Physiology and Biophysics, University of Mississippi Medical Center, and Research Service, G.V. (Sonny) Montgomery Veterans Affairs Medical Center, Jackson, MS, USA.
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Bernardo BC, Ooi JYY, Weeks KL, Patterson NL, McMullen JR. Understanding Key Mechanisms of Exercise-Induced Cardiac Protection to Mitigate Disease: Current Knowledge and Emerging Concepts. Physiol Rev 2018; 98:419-475. [PMID: 29351515 DOI: 10.1152/physrev.00043.2016] [Citation(s) in RCA: 93] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The benefits of exercise on the heart are well recognized, and clinical studies have demonstrated that exercise is an intervention that can improve cardiac function in heart failure patients. This has led to significant research into understanding the key mechanisms responsible for exercise-induced cardiac protection. Here, we summarize molecular mechanisms that regulate exercise-induced cardiac myocyte growth and proliferation. We discuss in detail the effects of exercise on other cardiac cells, organelles, and systems that have received less or little attention and require further investigation. This includes cardiac excitation and contraction, mitochondrial adaptations, cellular stress responses to promote survival (heat shock response, ubiquitin-proteasome system, autophagy-lysosomal system, endoplasmic reticulum unfolded protein response, DNA damage response), extracellular matrix, inflammatory response, and organ-to-organ crosstalk. We summarize therapeutic strategies targeting known regulators of exercise-induced protection and the challenges translating findings from bench to bedside. We conclude that technological advancements that allow for in-depth profiling of the genome, transcriptome, proteome and metabolome, combined with animal and human studies, provide new opportunities for comprehensively defining the signaling and regulatory aspects of cell/organelle functions that underpin the protective properties of exercise. This is likely to lead to the identification of novel biomarkers and therapeutic targets for heart disease.
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Affiliation(s)
- Bianca C Bernardo
- Baker Heart and Diabetes Institute , Melbourne , Australia ; Department of Paediatrics, University of Melbourne , Victoria , Australia ; Department of Diabetes, Central Clinical School, Monash University , Victoria , Australia ; Department of Medicine, Central Clinical School, Monash University , Victoria , Australia ; and Department of Physiology, School of Biomedical Sciences , Victoria , Australia
| | - Jenny Y Y Ooi
- Baker Heart and Diabetes Institute , Melbourne , Australia ; Department of Paediatrics, University of Melbourne , Victoria , Australia ; Department of Diabetes, Central Clinical School, Monash University , Victoria , Australia ; Department of Medicine, Central Clinical School, Monash University , Victoria , Australia ; and Department of Physiology, School of Biomedical Sciences , Victoria , Australia
| | - Kate L Weeks
- Baker Heart and Diabetes Institute , Melbourne , Australia ; Department of Paediatrics, University of Melbourne , Victoria , Australia ; Department of Diabetes, Central Clinical School, Monash University , Victoria , Australia ; Department of Medicine, Central Clinical School, Monash University , Victoria , Australia ; and Department of Physiology, School of Biomedical Sciences , Victoria , Australia
| | - Natalie L Patterson
- Baker Heart and Diabetes Institute , Melbourne , Australia ; Department of Paediatrics, University of Melbourne , Victoria , Australia ; Department of Diabetes, Central Clinical School, Monash University , Victoria , Australia ; Department of Medicine, Central Clinical School, Monash University , Victoria , Australia ; and Department of Physiology, School of Biomedical Sciences , Victoria , Australia
| | - Julie R McMullen
- Baker Heart and Diabetes Institute , Melbourne , Australia ; Department of Paediatrics, University of Melbourne , Victoria , Australia ; Department of Diabetes, Central Clinical School, Monash University , Victoria , Australia ; Department of Medicine, Central Clinical School, Monash University , Victoria , Australia ; and Department of Physiology, School of Biomedical Sciences , Victoria , Australia
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5
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Guzzoni V, Marqueti RDC, Durigan JLQ, Faustino de Carvalho H, Lino RLB, Mekaro MS, Costa Santos TO, Mecawi AS, Rodrigues JA, Hord JM, Lawler JM, Davel AP, Selistre-de-Araújo HS. Reduced collagen accumulation and augmented MMP-2 activity in left ventricle of old rats submitted to high-intensity resistance training. J Appl Physiol (1985) 2017; 123:655-663. [PMID: 28684598 DOI: 10.1152/japplphysiol.01090.2016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 06/23/2017] [Accepted: 06/29/2017] [Indexed: 01/09/2023] Open
Abstract
Progressive fibrosis is a hallmark of the aging heart. Age-related fibrosis is modulated by endurance exercise training; however, little is known concerning the influence of resistance training (RT). Therefore we investigated the chronic effects of high-intensity RT on age-associated alterations of left ventricle (LV) structure, collagen content, matrix metalloproteinase-2 (MMP-2), and extracellular matrix-related gene expression, including transforming growth factor-β (TGF-β). Young adult (3 mo) and aged (21 mo) male Wistar rats were submitted to a RT protocol (ladder climbing with 65, 85, 95, and 100% load), three times a week for 12 wk. Forty-eight hours posttraining, arterial systolic and diastolic pressure, LV end-diastolic pressure (LVEDP) and dP/dt were recorded. LV morphology, collagen deposition, and gene expression of type I (COL-I) and type III (COL-III) collagen, MMP-2, tissue inhibitor of metalloproteinases-1 (TIMP-1), and TGF-β1 were analyzed by quantitative reverse transcriptase-PCR. MMP-2 content was assessed by zymography. Increased collagen deposition was observed in LV from aged rats. These parameters were modulated by RT and were associated with increased MMP-2 activity and decreased COL-I, TGF-β1, and TIMP-1 mRNA content. Despite the effect of RT on collagen accumulation, there was no improvement on LVEDP and maximal negative LV dP/dt of aged rats. Cardiomyocyte diameter was preserved in all experimental conditions. In conclusion, RT attenuated age-associated collagen accumulation, concomitant to the increase in MMP-2 activity and decreased expression of COL-I, TGF-β1, and TIMP-1 in LV, illustrating a cardioprotective effect of RT on ventricular structure and function.NEW & NOTEWORTHY We demonstrated the beneficial resistance-training effect against age-related left ventricle collagen accumulation in the left ventricle, which was associated with decreased type I collagen (COL-I), transforming growth factor-β1 (TGF-β1), and tissue inhibitor of metalloproteinases-1 (TIMP-1) gene expression and matrix metalloproteinase-2 (MMP-2) activity. Our findings suggest for the first time the potential effects of resistance training in modulating collagen accumulation and possibly fibrosis in the aging heart.
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Affiliation(s)
- Vinicius Guzzoni
- Department of Physiological Sciences, Federal University of São Carlos, São Carlos, Brazil;
| | | | | | | | | | - Marcelo S Mekaro
- Department of Physiological Sciences, Federal University of São Carlos, São Carlos, Brazil
| | | | - André Souza Mecawi
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, São Paulo, Brazil; and
| | - José Antunes Rodrigues
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, São Paulo, Brazil; and
| | - Jeffrey M Hord
- Department of Health & Kinesiology, Texas A&M University, College Station, Texas
| | - Jonh M Lawler
- Department of Health & Kinesiology, Texas A&M University, College Station, Texas
| | - Ana Paula Davel
- Institute of Biology, State University of Campinas, Campinas, Brazil
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Vega RB, Konhilas JP, Kelly DP, Leinwand LA. Molecular Mechanisms Underlying Cardiac Adaptation to Exercise. Cell Metab 2017; 25:1012-1026. [PMID: 28467921 PMCID: PMC5512429 DOI: 10.1016/j.cmet.2017.04.025] [Citation(s) in RCA: 163] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 04/13/2017] [Accepted: 04/18/2017] [Indexed: 02/06/2023]
Abstract
Exercise elicits coordinated multi-organ responses including skeletal muscle, vasculature, heart, and lung. In the short term, the output of the heart increases to meet the demand of strenuous exercise. Long-term exercise instigates remodeling of the heart including growth and adaptive molecular and cellular re-programming. Signaling pathways such as the insulin-like growth factor 1/PI3K/Akt pathway mediate many of these responses. Exercise-induced, or physiologic, cardiac growth contrasts with growth elicited by pathological stimuli such as hypertension. Comparing the molecular and cellular underpinnings of physiologic and pathologic cardiac growth has unveiled phenotype-specific signaling pathways and transcriptional regulatory programs. Studies suggest that exercise pathways likely antagonize pathological pathways, and exercise training is often recommended for patients with chronic stable heart failure or following myocardial infarction. Herein, we summarize the current understanding of the structural and functional cardiac responses to exercise as well as signaling pathways and downstream effector molecules responsible for these adaptations.
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Affiliation(s)
- Rick B Vega
- Center for Metabolic Origins of Disease, Sanford Burnham Prebys Medical Discovery Institute at Lake Nona, Orlando, FL 32827, USA
| | - John P Konhilas
- Department of Physiology, Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson, AZ 85724, USA
| | - Daniel P Kelly
- Center for Metabolic Origins of Disease, Sanford Burnham Prebys Medical Discovery Institute at Lake Nona, Orlando, FL 32827, USA
| | - Leslie A Leinwand
- Molecular, Cellular and Developmental Biology, BioFrontiers Institute, University of Colorado, Boulder, CO 80309, USA.
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7
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Meschiari CA, Ero OK, Pan H, Finkel T, Lindsey ML. The impact of aging on cardiac extracellular matrix. GeroScience 2017; 39:7-18. [PMID: 28299638 PMCID: PMC5352584 DOI: 10.1007/s11357-017-9959-9] [Citation(s) in RCA: 145] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 01/05/2017] [Indexed: 12/24/2022] Open
Abstract
Age-related changes in cardiac homeostasis can be observed at the cellular, extracellular, and tissue levels. Progressive cardiomyocyte hypertrophy, inflammation, and the gradual development of cardiac fibrosis are hallmarks of cardiac aging. In the absence of a secondary insult such as hypertension, these changes are subtle and result in slight to moderate impaired myocardial function, particularly diastolic function. While collagen deposition and cross-linking increase during aging, extracellular matrix (ECM) degradation capacity also increases due to increased expression of matrix metalloproteinases (MMPs). Of the MMPs elevated with cardiac aging, MMP-9 has been extensively evaluated and its roles are reviewed here. In addition to proteolytic activity on ECM components, MMPs oversee cell signaling during the aging process by modulating cytokine, chemokine, growth factor, hormone, and angiogenic factor expression and activity. In association with elevated MMP-9, macrophage numbers increase in an age-dependent manner to regulate the ECM and angiogenic responses. Understanding the complexity of the molecular interactions between MMPs and the ECM in the context of aging may provide novel diagnostic indicators for the early detection of age-related fibrosis and cardiac dysfunction.
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Affiliation(s)
- Cesar A Meschiari
- Mississippi Center for Heart Research, Department of Physiology and Biophysics, University of Mississippi Medical Center, 2500 North State Street, Room G351-04, Jackson, MS, USA
| | - Osasere Kelvin Ero
- Mississippi Center for Heart Research, Department of Physiology and Biophysics, University of Mississippi Medical Center, 2500 North State Street, Room G351-04, Jackson, MS, USA
| | - Haihui Pan
- Center for Molecular Medicine, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD, USA
| | - Toren Finkel
- Center for Molecular Medicine, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD, USA
| | - Merry L Lindsey
- Mississippi Center for Heart Research, Department of Physiology and Biophysics, University of Mississippi Medical Center, 2500 North State Street, Room G351-04, Jackson, MS, USA.
- G.V. (Sonny) Montgomery Veterans Affairs Medical Center, Jackson, MS, 39216-4505, USA.
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8
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Pedro RE, Guariglia DA, Okuno NM, Deminice R, Peres SB, Moraes SMF. Effects of 16 Weeks of Concurrent Training on Resting Heart Rate Variability and Cardiorespiratory Fitness in People Living With HIV/AIDS Using Antiretroviral Therapy: A Randomized Clinical Trial. J Strength Cond Res 2016; 30:3494-3502. [PMID: 27191693 DOI: 10.1519/jsc.0000000000001454] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Pedro, RE, Guariglia, DA, Okuno, NM, Deminice, R, Peres, SB, and Moraes, SMF. Effects of 16 weeks of concurrent training on resting heart rate variability and cardiorespiratory fitness in people living with HIV/AIDS using antiretroviral therapy: a randomized clinical trial. J Strength Cond Res 30(12): 3494-3502, 2016-The study evaluated the effects of concurrent training on resting heart rate variability (HRVrest) and cardiorespiratory fitness in people living with HIV/AIDS undergoing antiretroviral therapy (ART). Fifty-eight participants were randomized into 2 groups (control and training group); however, only 33 were analyzed. The variables studied were HRVrest indices, submaximal values of oxygen uptake (V[Combining Dot Above]O2sub) and heart rate (HR5min), peak speed (Vpeak), and peak oxygen uptake (V[Combining Dot Above]O2peak). The training group performed concurrent training (15-20 minutes of aerobic exercise plus 40 minutes of resistance exercise), 3 times per week, for 16 weeks. Posttraining V[Combining Dot Above]O2peak and Vpeak increased, and HR5min decreased. Resting heart rate variability indices did not present statistical differences posttraining; however, the magnitude-based inferences demonstrated a "possibly positive effect" for high frequency (HF) and low frequency (LF) plus high frequency (LF + HF) and a "likely positive effect" for R-Rmean posttraining. In conclusion, concurrent training was effective at improving cardiorespiratory fitness and endurance performance. Moreover, it led to probably a positive effect on HF and a likely positive effect on R-Rmean in people living with HIV/AIDS undergoing ART.
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Affiliation(s)
- Rafael E Pedro
- 1Department of Physical Education, State University of Maringa, Maringá, Brazil; 2Associate Post-graduate Program in Physical Education, Department of Physical Education, UEM/UEL, Maringá/Londrina, Brazil; 3Department of Physical Education, State University of Ponta Grossa, Ponta Grossa, Brazil; 4Department of Physical Education, State University of Londrina, Londrina, Brazil; and 5Department of Physiological Sciences, State University of Maringa, Maringá, Brazil
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Horn MA, Trafford AW. Aging and the cardiac collagen matrix: Novel mediators of fibrotic remodelling. J Mol Cell Cardiol 2016; 93:175-85. [PMID: 26578393 PMCID: PMC4945757 DOI: 10.1016/j.yjmcc.2015.11.005] [Citation(s) in RCA: 161] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 11/02/2015] [Accepted: 11/04/2015] [Indexed: 01/05/2023]
Abstract
Cardiovascular disease is a leading cause of death worldwide and there is a pressing need for new therapeutic strategies to treat such conditions. The risk of developing cardiovascular disease increases dramatically with age, yet the majority of experimental research is executed using young animals. The cardiac extracellular matrix (ECM), consisting predominantly of fibrillar collagen, preserves myocardial integrity, provides a means of force transmission and supports myocyte geometry. Disruptions to the finely balanced control of collagen synthesis, post-synthetic deposition, post-translational modification and degradation may have detrimental effects on myocardial functionality. It is now well established that the aged heart is characterized by fibrotic remodelling, but the mechanisms responsible for this are incompletely understood. Furthermore, studies using aged animal models suggest that interstitial remodelling with disease may be age-dependent. Thus with the identification of new therapeutic strategies targeting fibrotic remodelling, it may be necessary to consider age-dependent mechanisms. In this review, we discuss remodelling of the cardiac collagen matrix as a function of age, whilst highlighting potential novel mediators of age-dependent fibrotic pathways.
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Affiliation(s)
- Margaux A Horn
- Institute of Cardiovascular Sciences, Manchester Academic Health Sciences Centre, 3.06 Core Technology Facility, 46 Grafton Street, Manchester M13 9NT, United Kingdom.
| | - Andrew W Trafford
- Institute of Cardiovascular Sciences, Manchester Academic Health Sciences Centre, 3.06 Core Technology Facility, 46 Grafton Street, Manchester M13 9NT, United Kingdom
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Souza RRD, Santos SMD, Maifrino LBM, Gama EF, Caperuto EC, Maldonado DC. Resistance training attenuates the effects of aging in the aorta of Wistar rats. MOTRIZ: REVISTA DE EDUCACAO FISICA 2015. [DOI: 10.1590/s1980-65742015000400012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023] Open
Abstract
Abstract The objective of the present study was to follow the structural modifications of the aortic wall in middle-aged rats submitted to a resistance training protocol for a period of four months. Three groups of 8 animals per group were considered: middle-aged group (MA), old control group (OC) and old trained group (OT). Training consisted in to climb a 1.1-m vertical (80° incline) ladder with weights tied to their tail. Aortic wall structural modifications were studied through light and electron microscopy and morphometry. The mean arterial blood pressure at rest was similar in the three experimental groups (p = .07). At the beginning of the experiment, the OC and OT groups had similar repetition maximums, ranging from 1.6-fold to 1.9-fold the body weight. At the end of the experiment, the repetition maximum of the OT group was 5-fold greater than the body weight (p = .03). The LV weight was 15% larger in the OT group than in the MA group and 12% larger than in the OC group (p = .02). The LV wall thickness of the OT group was significantly larger than that of both, the MA group and the OC group (p = .03). The LV internal diameter in the OT group was significantly smaller than that observed in the MA and OC groups (p = .02). Resistance training diminished the alterations associated with aging improving aortic wall structure by reducing the thickness, normalising the elastic material, the collagen and the smooth muscle cells. Resistance training seems to be a potential treatment for reducing the deleterious effects of aging on the aortic wall.
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11
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Lee Y, Kwak HB, Hord J, Kim JH, Lawler JM. Exercise training attenuates age-dependent elevation of angiotensin II type 1 receptor and Nox2 signaling in the rat heart. Exp Gerontol 2015; 70:163-73. [DOI: 10.1016/j.exger.2015.07.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Revised: 07/26/2015] [Accepted: 07/30/2015] [Indexed: 11/25/2022]
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13
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Song W, Wang X. The role of TGFβ1 and LRG1 in cardiac remodelling and heart failure. Biophys Rev 2015; 7:91-104. [PMID: 28509980 PMCID: PMC4322186 DOI: 10.1007/s12551-014-0158-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 11/26/2014] [Indexed: 12/12/2022] Open
Abstract
Heart failure is a life-threatening condition that carries a considerable emotional and socio-economic burden. As a result of the global increase in the ageing population, sedentary life-style, increased prevalence of risk factors, and improved survival from cardiovascular events, the incidence of heart failure will continue to rise. Despite the advances in current cardiovascular therapies, many patients are not suitable for or may not benefit from conventional treatments. Thus, more effective therapies are required. Transforming growth factor (TGF) β family of cytokines is involved in heart development and dys-regulated TGFβ signalling is commonly associated with fibrosis, aberrant angiogenesis and accelerated progression into heart failure. Therefore, a potential therapeutic pathway is to modulate TGFβ signalling; however, broad blockage of TGFβ signalling may cause unwanted side effects due to its pivotal role in tissue homeostasis. We found that leucine-rich α-2 glycoprotein 1 (LRG1) promotes blood vessel formation via regulating the context-dependent endothelial TGFβ signalling. This review will focus on the interaction between LRG1 and TGFβ signalling, their involvement in the pathogenesis of heart failure, and the potential for LRG1 to function as a novel therapeutic target.
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Affiliation(s)
- Weihua Song
- Division of Metabolic Medicine, Lee Kong Chian School of Medicine, Nanyang Technological University, Research Techno Plaza, X-Frontiers Block, Level 4, 50 Nan yang Drive, Singapore, 637553, Singapore
| | - Xiaomeng Wang
- Division of Metabolic Medicine, Lee Kong Chian School of Medicine, Nanyang Technological University, Research Techno Plaza, X-Frontiers Block, Level 4, 50 Nan yang Drive, Singapore, 637553, Singapore. .,Division of Cell Biology in Health and Disease, Institute of Molecular and Cell Biology, Singapore Agency for Science, Technology and Research, 61 Biopolis Drive, Proteos, Singapore, 138673, Singapore. .,Department of Cell Biology, Institute of Ophthalmology, University College London, 11-43 Bath Street, London, EC1V 9EL, UK.
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De Souza MR, Pimenta L, Pithon-Curi TC, Bucci M, Fontinele RG, De Souza RR. Effects of aerobic training, resistance training, or combined resistance-aerobic training on the left ventricular myocardium in a rat model. Microsc Res Tech 2014; 77:727-34. [PMID: 24954110 DOI: 10.1002/jemt.22394] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Revised: 05/29/2014] [Accepted: 06/08/2014] [Indexed: 11/08/2022]
Abstract
This study follows the left ventricular (LV) hypertrophy in rats undergoing aerobic training alone (A), resistance training alone (R), or combined resistance and aerobic training (RA) (usually referred as concurrent training) program. A sedentary control group (C) was included. LV remodeling was evaluated using electron and light microscopy. The LV weight to body weight (LVW: BW) increased 11.4% in A group, 35% in the R group, and 18% in the RA group compared to the C group. The LV thickness increased 6% in the A group, 17% in the R group, and 10% in the RA group. The LV internal diameter increased 19% in the A group, 3% in the R group, and 8% in the RA group compared with the C group. The cross-sectional area of cardiomyocyte increased by 1% with the A group, 27% with R group, and 12% with RA training. The capillary density increased by 5.4% with A training, 11.0% with R training, and 7.7% with RA training compared with the C group. The volume fraction of interstitial collagen increased by 0.4% with training A, increased by 2.8% with R training, and 0.9% with RA training. In conclusion, except for the LV internal diameter, which increased more in the A group, the cardiac parameters increased more in the R group than in the other groups and in RA group than in A group. Collagen density increased from 5.4 ± 0.8% in the C group to 5.8 ± 0.6% in the A group (n. s.) (P > 0.05), to 8.2 ± 0.7% in the R group (P < 0.05), and to 6.3 ± 0.4% in the RA group (P < 0.05). These results demonstrate a significant increase for collagen content in the LV with R and RA exercise, but the increase was higher with R training alone than with RA training.
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Wright KJ, Thomas MM, Betik AC, Belke D, Hepple RT. Exercise training initiated in late middle age attenuates cardiac fibrosis and advanced glycation end-product accumulation in senescent rats. Exp Gerontol 2014; 50:9-18. [DOI: 10.1016/j.exger.2013.11.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2013] [Revised: 10/12/2013] [Accepted: 11/18/2013] [Indexed: 11/28/2022]
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Kwak HB. Aging, exercise, and extracellular matrix in the heart. J Exerc Rehabil 2013; 9:338-47. [PMID: 24278882 PMCID: PMC3836529 DOI: 10.12965/jer.130049] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 06/13/2013] [Accepted: 06/20/2013] [Indexed: 11/22/2022] Open
Abstract
Aging is characterized by a progressive impairment of (a) cardiac structure including fibrosis and cardiomyocyte density, and (b) cardiac function including stroke volume, ejection fraction, and cardiac output. The cardiac remodeling involves loss of cardiac myocytes, reactive hypertrophy of the remaining cells, and increased extracellular matrix (ECM) and fibrosis in the aging heart, especially left ventricles. Fibrosis (i.e., accumulation of collagen) with aging is very critical in impairing cardiac function associated with increased myocardial stiffness. The balance of ECM remodeling via ECM synthesis and degradation is essential for normal cardiac structure and function. Thus an understanding of upstream ECM regulatory factors such as matrix metalloproteinases (MMPs), tissue inhibitors of metalloproteinases (TIMPs), tumor necrosis factor-α (TNF-α), transforming growth factor-β (TGF-β), and myofibroblasts is necessary for gaining new insights into managing cardiac remodeling and dysfunction with aging. In contrast, exercise training effectively improves cardiac function in both young and older individuals. Exercise training also improves maximal cardiovascular function by increasing stroke volume and cardiac output. However, limited data indicate that exercise training might attenuate collagen content and remodeling in the aging heart. We recently found that 12 weeks of exercise training protected against geometric changes of collagen ECM in the aging heart and ameliorated age-associated dysregulation of ECM in the heart, as indicated by up-regulation of active MMPs as well as down-regulation of TIMPs and TGF-β. This review will provide a summary and discussion of aging and exercise effects on fibrosis and upstream regulators of ECM in the heart.
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Affiliation(s)
- Hyo-Bum Kwak
- Department of Kinesiology, Inha University, Incheon, Korea
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Yengo CM, Zimmerman SD, McCormick RJ, Thomas DP. Exercise training post-MI favorably modifies heart extracellular matrix in the rat. Med Sci Sports Exerc 2012; 44:1005-12. [PMID: 22217559 DOI: 10.1249/mss.0b013e318244bc8a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
PURPOSE In order to assess the effect of daily exercise on extracellular matrix remodeling in the heart after myocardial infarction (MI), we measured collagen concentration (%COL) and nonreducible collagen cross-linking (hydroxylysylpyridinoline, HP) in the right ventricle (RV), and regionally within the infarcted (INF) and viable left ventricular free wall (LVF) and septum (LVS), using a rodent MI training model. METHODS Infarcts (19%-24% of LV) were surgically induced in adult rats that were assigned to either trained (MI-TR) or sedentary (MI-SED) groups and compared to sham-surgery sedentary controls (SHAM). RESULTS In LVF, 10 wk of treadmill running had no effect on the increase (P < 0.001) in %COL seen with MI (MI-SED = 7.14% ± 0.15%, MI-TR = 7.61% ± 0.19%, SHAM = 3.55% ± 0.19%). However, it normalized the increase (P < 0.05) in HP cross-linking (MI-SED = 0.43 ± 0.02, MI-TR = 0.27 ± 0.03, SHAM = 0.30 ± 0.04 mol HP·mol(-1) collagen). The INF scar in MI-SED rats showed a sevenfold increase in %COL (P < 0.001) compared to SHAM LVF myocardium, an increase that was attenuated by training (MI-SED = 26% ± 1% vs MI-TR = 21% ± 2%; P < 0.05). However, training had no effect on MI-induced increases in cross-linking in the INF scar (1.01 ± 0.22 vs 0.84 ± 0.14 mol HP·mol(-1) collagen). In LVS, although a small but significant increase in %COL was seen in both MI groups, HP cross-linking was unaltered compared to SHAM rats. Training also normalized the increase observed in cross-linking in RV after MI. CONCLUSIONS Because increased HP cross-linking in the heart is associated with decreased chamber compliance, these findings may help to explain the improved heart function seen after daily exercise in cardiac rehabilitation patients.
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Affiliation(s)
- Christopher M Yengo
- Department of Cellular and Molecular Physiology, Penn State College of Medicine, Hershey, PA, USA
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Ma Y, Chiao YA, Zhang J, Manicone AM, Jin YF, Lindsey ML. Matrix metalloproteinase-28 deletion amplifies inflammatory and extracellular matrix responses to cardiac aging. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2012; 18:81-90. [PMID: 22153350 PMCID: PMC3972008 DOI: 10.1017/s1431927611012220] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
To determine if matrix metalloproteinase (MMP)-28 mediates cardiac aging, wild-type (WT) and MMP-28-/- young (7 ± 1 months, n = 9 each) and old (20 ± 2 months, n = 7 each) female mice were evaluated. MMP-28 expression in the left ventricle (LV) increased 42% in old WT mice compared to young controls (p < 0.05). By Doppler echocardiography, LV function declined at 20 ± 2 months of age for both groups. However, dobutamine stress responses were similar, indicating that cardiac reserve was maintained. Plasma proteomic profiling revealed that macrophage inflammatory protein (MIP)-1 α, MIP-1β and MMP-9 plasma levels did not change in WT old mice but were significantly elevated in MMP-28-/- old mice (all p < 0.05), suggestive of a higher inflammatory status when MMP-28 is deleted. RT2-PCR gene array and immunoblotting analyses demonstrated that MIP-1α and MMP-9 gene and protein levels in the LV were also higher in MMP-28-/- old mice (all p < 0.05). Macrophage numbers in the LV increased similarly in WT and MMP-28-/- old mice, compared to respective young controls (both p < 0.05). Collagen content was not different among the WT and MMP-28-/- young and old mice. In conclusion, LV inflammation increases with age, and MMP-28 deletion further elevates inflammation and extracellular matrix responses, without altering macrophage numbers or collagen content.
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Affiliation(s)
- Yonggang Ma
- Barshop Institute of Longevity and Aging Studies, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78245, USA
- Division of Geriatrics, Gerontology and Palliative Medicine, Department of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78245, USA
| | - Ying Ann Chiao
- Barshop Institute of Longevity and Aging Studies, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78245, USA
- Division of Geriatrics, Gerontology and Palliative Medicine, Department of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78245, USA
- Department of Biochemistry, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78245, USA
| | - Jianhua Zhang
- Barshop Institute of Longevity and Aging Studies, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78245, USA
- Division of Geriatrics, Gerontology and Palliative Medicine, Department of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78245, USA
| | - Anne M. Manicone
- Center for Lung Biology and Division of Pulmonary and Critical Care Medicine, University of Washington, Seattle, WA 98109, USA
| | - Yu-Fang Jin
- Department of Electrical and Computer Engineering, The University of Texas at San Antonio, San Antonio, TX 78245, USA
| | - Merry L. Lindsey
- Barshop Institute of Longevity and Aging Studies, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78245, USA
- Division of Geriatrics, Gerontology and Palliative Medicine, Department of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78245, USA
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Abstract
Western societies are rapidly aging, and cardiovascular diseases are the leading cause of death. In fact, age and cardiovascular diseases are positively correlated, and disease syndromes affecting the heart reach epidemic proportions in the very old. Genetic variations and molecular adaptations are the primary contributors to the onset of cardiovascular disease; however, molecular links between age and heart syndromes are complex and involve much more than the passage of time. Changes in CM (cardiomyocyte) structure and function occur with age and precede anatomical and functional changes in the heart. Concomitant with or preceding some of these cellular changes are alterations in gene expression often linked to signalling cascades that may lead to a loss of CMs or reduced function. An understanding of the intrinsic molecular mechanisms underlying these cascading events has been instrumental in forming our current understanding of how CMs adapt with age. In the present review, we describe the molecular mechanisms underlying CM aging and how these changes may contribute to the development of cardiovascular diseases.
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Nandrolone and resistance training induce heart remodeling: Role of fetal genes and implications for cardiac pathophysiology. Life Sci 2011; 89:631-7. [DOI: 10.1016/j.lfs.2011.08.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Revised: 06/30/2011] [Accepted: 07/27/2011] [Indexed: 01/13/2023]
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Chen W, Frangogiannis NG. The role of inflammatory and fibrogenic pathways in heart failure associated with aging. Heart Fail Rev 2011; 15:415-22. [PMID: 20213186 DOI: 10.1007/s10741-010-9161-y] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Heart failure is strongly associated with aging. Elderly patients with heart failure often have preserved systolic function exhibiting left ventricular hypertrophy accompanied by a decline in diastolic function. Experimental studies have demonstrated that age-related cardiac fibrosis plays an important role in the pathogenesis of diastolic heart failure in senescent hearts. Reactive oxygen species and angiotensin II are critically involved in fibrotic remodeling of the aging ventricle; their fibrogenic actions may be mediated, at least in part, through transforming growth factor (TGF)-beta. The increased prevalence of heart failure in the elderly is also due to impaired responses of the senescent heart to cardiac injury. Aging is associated with suppressed inflammation, delayed phagocytosis of dead cardiomyocytes, and markedly diminished collagen deposition following myocardial infarction, due to a blunted response of fibroblasts to fibrogenic growth factors. Thus, in addition to a baseline activation of fibrogenic pathways, senescent hearts exhibit an impaired reparative reserve due to decreased responses of mesenchymal cells to stimulatory signals. Impaired scar formation in senescent hearts is associated with accentuated dilative remodeling and worse systolic dysfunction. Understanding the pathogenesis of interstitial fibrosis in the aging heart and dissecting the mechanisms responsible for age-associated healing defects following cardiac injury are critical in order to design new strategies for prevention of adverse remodeling and heart failure in elderly patients.
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Affiliation(s)
- Wei Chen
- Section of Cardiovascular Sciences, Baylor College of Medicine, One Baylor Plaza BCM620, Houston, TX 77030, USA
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Collagen and reticular fibers in left ventricular muscle in diabetic rats: Physical exercise prevents its changes? Tissue Cell 2011; 43:24-8. [DOI: 10.1016/j.tice.2010.11.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2010] [Revised: 11/02/2010] [Accepted: 11/03/2010] [Indexed: 11/20/2022]
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Kwak HB, Kim JH, Joshi K, Yeh A, Martinez DA, Lawler JM. Exercise training reduces fibrosis and matrix metalloproteinase dysregulation in the aging rat heart. FASEB J 2010; 25:1106-17. [PMID: 21148111 DOI: 10.1096/fj.10-172924] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Aging impairs function in the nonischemic heart and is associated with mechanical remodeling. This process includes accumulation of collagen (i.e., fibrosis) and dysregulation of active matrix metalloproteinases (MMPs). Exercise training (ET) improves cardiac function, but the pathways of protection remain poorly understood. Young (3 mo) and old (31 mo) FBNF1 rats were assigned into sedentary and exercise groups, with ET group rats training on a treadmill 45 min/d, 5 d/wk for 12 wk. Nonlinear optical microscopy (NLOM), histology, immunohistochemistry (IHC), and Western blot analyses were performed on the left ventricle and septum. NLOM, IHC, and histological imaging revealed that ET reduced age-associated elevation of collagen type I fibers. Active MMP-1, active MMP-2, and MMP-14 in the ECM fraction of the left ventricle were reduced by aging, an effect abrogated by ET. Tissue inhibitor of MMP (TIMP-1) was elevated with age but protected by ET. Transforming growth factor-β (TGF-β), upstream regulator of TIMP-1, increased with age but was attenuated by ET. Therefore, exercise training could protect the aging heart against dysregulation of MMPs and fibrosis by suppressing elevation of TIMP-1 and TGF-β.
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Affiliation(s)
- Hyo-Bum Kwak
- Redox Biology and Cell Signaling Laboratory, Department of Health and Kinesiology, Texas A&M University, College Station, TX 77843-4243, USA
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Choi SI, Chang HJ, Chun EJ, Cho SB, Kim ST, Yoon YE, Chang SA, Kim JH, Kim CH, Lim TH. Exercise training improves age-related myocardial metabolic derangement: proton magnetic resonance spectroscopy study in the rat model. Korean Circ J 2010; 40:454-8. [PMID: 20967147 PMCID: PMC2957643 DOI: 10.4070/kcj.2010.40.9.454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2008] [Revised: 11/18/2009] [Accepted: 01/05/2010] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND AND OBJECTIVES The objective of this study was to determine whether long-term exercise training will improve age-related cardiac metabolic derangement using proton magnetic resonance (MR) spectroscopy. MATERIALS AND METHODS Young and old male Fischer 344 rats were assigned to sedentary controls groups {young control (YC) group-3 months of age: YC, n=10; old control (OC) group-22 months of age: OC, n=10}, and an exercise training group (OT, n=5). After 12-week of treadmill exercise training, MR spectroscopy at 4.7 T was performed to assess myocardial energy metabolism: measurements of myocardial creatine-to-water ratio (Scr/Sw) were performed using the XWIN-NMR software. RESULTS Exercise capacity was 14.7 minutes greater in OT than that in OC (20.1±1.9 minutes in OT, 5.4±2.3 minutes in OC; p<0.001). The 12-week exercise training rendered the old rats a maximum exercise capacity matching that of untrained YC rats (17.9±1.5 minutes in YC, 20.1±1.9 minutes in OT; p>0.05). The creatine-to-water ratios in the interventricular septa of YC did not differ significantly from that of OT (0.00131±0.00025 vs. 0.00127±0.00031; p=0.37). However, OC showed significant reduction in creatine-to-water ratio compared to OT (0.00096±0.00025 vs. 0.00127±0.00031; p<0.001). Mean total creatine concentrations in the myocardium were similar between YC and OT (13.3±3.6 vs. 11.5±4.1 mmol/kg wet weight; p=0.29). In contrast, the mean total creatine concentration of OC was significantly reduced compared to OT (6.8±3.2 vs. 11.5±4.1 mmol/kg wet weight; p=0.03). CONCLUSION Our findings suggest that long-term exercise training in old rats induced prevention of age-related deterioration in myocardial metabolism.
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Affiliation(s)
- Sang Il Choi
- Department of Radiology, Seoul National University Bundang Hospital, Seongnam, Korea
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Ozaki H, Miyachi M, Nakajima T, Abe T. Effects of 10 weeks walk training with leg blood flow reduction on carotid arterial compliance and muscle size in the elderly adults. Angiology 2010; 62:81-6. [PMID: 20682613 DOI: 10.1177/0003319710375942] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
High-intensity resistance training increases muscle size, but reduces arterial compliance. Muscular blood flow reduction (BFR) during low-intensity training has been shown to elicit muscle hypertrophy. However, the effect on arterial compliance is unknown. We examined the effects of walk training with BFR on carotid arterial compliance and muscle size in the elderly adults. Both BFR-walk training (BFR-W, n = 13, 66 ± 1 year) and control-walk training (CON-W, n = 10, 68 ± 1 year) groups performed 20 minutes treadmill walking at an exercise intensity of 45% of heart rate reserve, 4 days/week for 10 weeks. The BFR-W group wore pressure cuffs on both legs during training. Maximum knee joint strength (∼15%) and MRI-measured thigh muscle cross-sectional area (3%) increased in the BFR-W, but not in the CON-W. Carotid arterial compliance improved in both BFR-W (50%) and CON-W (59%) groups. Walk training with blood flow reduction can improve thigh muscle size/strength as well as carotid arterial compliance, unlike high-intensity training, in the elderly.
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Bradshaw AD, Baicu CF, Rentz TJ, Van Laer AO, Bonnema DD, Zile MR. Age-dependent alterations in fibrillar collagen content and myocardial diastolic function: role of SPARC in post-synthetic procollagen processing. Am J Physiol Heart Circ Physiol 2010; 298:H614-22. [PMID: 20008277 PMCID: PMC2822576 DOI: 10.1152/ajpheart.00474.2009] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2009] [Accepted: 12/04/2009] [Indexed: 01/19/2023]
Abstract
Advanced age, independent of concurrent cardiovascular disease, can be associated with increased extracellular matrix (ECM) fibrillar collagen content and abnormal diastolic function. However, the mechanisms causing this left ventricular (LV) remodeling remain incompletely defined. We hypothesized that one determinant of age-dependent remodeling is a change in the extent to which newly synthesized procollagen is processed into mature collagen fibrils. We further hypothesized that secreted protein acidic and rich in cysteine (SPARC) plays a key role in the changes in post-synthetic procollagen processing that occur in the aged myocardium. Young (3 mo old) and old (18-24 mo old) wild-type (WT) and SPARC-null mice were studied. LV collagen content was measured histologically by collagen volume fraction, collagen composition was measured by hydroxyproline assay as soluble collagen (1 M NaCl extractable) versus insoluble collagen (mature cross-linked), and collagen morphological structure was examined by scanning electron microscopy. SPARC expression was measured by immunoblot analysis. LV and myocardial structure and function were assessed using echocardiographic and papillary muscle experiments. In WT mice, advanced age increased SPARC expression, myocardial diastolic stiffness, fibrillar collagen content, and insoluble collagen. In SPARC-null mice, advanced age also increased myocardial diastolic stiffness, fibrillar collagen content, and insoluble collagen but significantly less than those seen in WT old mice. As a result, insoluble collagen and myocardial diastolic stiffness were lower in old SPARC-null mice (1.36 +/- 0.08 mg hydroxyproline/g dry wt and 0.04 +/- 0.005) than in old WT mice (1.70 +/- 0.10 mg hydroxyproline/g dry wt and 0.07 +/- 0.005, P < 0.05). In conclusion, the absence of SPARC reduced age-dependent alterations in ECM fibrillar collagen and diastolic function. These data support the hypothesis that SPARC plays a key role in post-synthetic procollagen processing and contributes to the increase in collagen content found in the aged myocardium.
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Affiliation(s)
- Amy D Bradshaw
- Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, USA.
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Choi SY, Chang HJ, Choi SI, Kim KI, Cho YS, Youn TJ, Chung WY, Chae IH, Choi DJ, Kim HS, Kim CH, Oh BH, Kim MH. Long-term exercise training attenuates age-related diastolic dysfunction: association of myocardial collagen cross-linking. J Korean Med Sci 2009; 24:32-9. [PMID: 19270810 PMCID: PMC2650965 DOI: 10.3346/jkms.2009.24.1.32] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2008] [Accepted: 05/23/2008] [Indexed: 12/03/2022] Open
Abstract
The incidence of diastolic heart failure increases dramatically with age. We investigated the impact of long-term exercise training on age-related diastolic dysfunction. Old (25-month-old) male Fischer 344 rats were studied after 12 weeks of treadmill exercise training or sedentary cage life (N=7, in each group). We determined cardiac performance using a pressure-volume conductance catheter and magnetic resonance imaging. Collagen volume fraction (CVF) and myocardial collagen solubility by pepsin as an index of advanced glycation end products (AGEs) cross-linked collagen were measured. The maximal slope of systolic pressure increment (+dP/dt) and the slope of end-systolic pressure-volume relation were higher, and end diastolic volume (EDV), Delta EDV (the percentage of the EDV increment-to-baseline EDV) and the slope of end-diastolic pressure-volume relation were lower in training group. The maximal slope of diastolic pressure decrement (-dP/dt) and time constant of LV pressure decay (tau) had no difference. AGEs cross-linked collagen, not CVF was reduced by exercise training. Long-term exercise training appears to attenuate age-related deterioration in cardiac systolic function and myocardial stiffness and could be reduce in pathologic AGEs cross-linked collagen in myocardium.
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Affiliation(s)
- Su-Yeon Choi
- Department of Internal Medicine, Seoul National University College of Medicine, Cardiovascular Center, Cardiovascular Research Institute and Healthcare Research Institute, Seoul National University Hospital, Seoul, Korea
| | - Hyuk-Jae Chang
- Department of Internal Medicine, Seoul National University College of Medicine, Cardiovascular Center and Cardiovascular Research Institute, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Sang-Il Choi
- Department of Radiology, Seoul National University College of Medicine, Cardiovascular Center and Cardiovascular Research Institute, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Kwang-Il Kim
- Department of Internal Medicine, Seoul National University College of Medicine, Cardiovascular Center and Cardiovascular Research Institute, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Yong-Seok Cho
- Department of Internal Medicine, Seoul National University College of Medicine, Cardiovascular Center and Cardiovascular Research Institute, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Tae-Jin Youn
- Department of Internal Medicine, Seoul National University College of Medicine, Cardiovascular Center and Cardiovascular Research Institute, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Woo-Young Chung
- Department of Internal Medicine, Seoul National University College of Medicine, Cardiovascular Center and Cardiovascular Research Institute, Seoul National University Bundang Hospital, Seongnam, Korea
| | - In-Ho Chae
- Department of Internal Medicine, Seoul National University College of Medicine, Cardiovascular Center and Cardiovascular Research Institute, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Dong-Ju Choi
- Department of Internal Medicine, Seoul National University College of Medicine, Cardiovascular Center and Cardiovascular Research Institute, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Hyo-Soo Kim
- Department of Internal Medicine, Seoul National University College of Medicine, Cardiovascular Center, Cardiovascular Research Institute and Healthcare Research Institute, Seoul National University Hospital, Seoul, Korea
| | - Cheol-Ho Kim
- Department of Internal Medicine, Seoul National University College of Medicine, Cardiovascular Center and Cardiovascular Research Institute, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Byung-Hee Oh
- Department of Internal Medicine, Seoul National University College of Medicine, Cardiovascular Center, Cardiovascular Research Institute and Healthcare Research Institute, Seoul National University Hospital, Seoul, Korea
| | - Mi-Hyang Kim
- Department of Food and Nutrition, College of Natural Science, Silla University, Busan, Korea
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Groban L, Jobe H, Lin M, Houle T, Kitzman DA, Sonntag W. Effects of short-term treadmill exercise training or growth hormone supplementation on diastolic function and exercise tolerance in old rats. J Gerontol A Biol Sci Med Sci 2008; 63:911-20. [PMID: 18840795 DOI: 10.1093/gerona/63.9.911] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Whether the lusitropic potential of short-term exercise in aged rats is linked to an augmentation in the growth hormone/insulin-like growth factor-1 (GH/IGF-1) axis and an alteration in the cardiac renin angiotensin system (RAS) is unknown. Old (28-month-old) male, Fischer 344xBrown Norway rats were randomized to 4 weeks of GH supplementation (300 microg subcutaneous, twice daily) or 4 weeks of treadmill running, or were used as sedentary controls. Six-month-old rats, sedentary or exercised, were used as young controls. Training improved exercise capacity in old animals. Exercise and GH attenuated age-related declines in myocardial relaxation despite an exercise-induced suppression of IGF-1. The regulatory protein, sarcoplasmic Ca2+ adenosine triphosphatase (SERCA2), increased with exercise but not GH. Among aged rats, the cardiac RAS was not altered by training or GH. Thus, the signaling pathway underlying the lusitropic benefit of short-term habitual exercise in the aged rat may be distinct from GH-mediated benefits and independent of the cardiac RAS.
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Affiliation(s)
- Leanne Groban
- Department of Anesthesiology, Wake Forest University School of Medicine, Medical Center Blvd., Winston-Salem, NC 27157-1009, USA.
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Kriegel AJ, Greene AS. Substitution of Brown Norway chromosome 16 preserves cardiac function with aging in a salt-sensitive Dahl consomic rat. Physiol Genomics 2008; 36:35-42. [PMID: 18940898 DOI: 10.1152/physiolgenomics.00054.2008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Determination of the genetic factors that control the progression of left ventricular hypertrophy (LVH) to heart failure has been difficult despite extensive study in animal models. Here we have characterized a consomic rat model of LVH resulting from the introgression of chromosome 16 from the normotensive Brown Norway (BN) rat onto the genetic background of the Dahl salt-sensitive (SS/Mcwi) rat by marker assisted breeding. The SS-16BN/Mcwi consomic rats are normotensive but display LVH equivalent to the hypertensive SS/Mcwi rats at early ages. In this study we tracked the development of LVH by echocardiography and analyzed changes in cardiac function and morphology with aging in the SS-16BN/Mcwi, SS/Mcwi, and BN to determine if the consomic SS-16BN/Mcwi was a model of hypertrophic cardiomyopathy (HCM). Aging SS-16BN/Mcwi rats showed no evidence of heart failure or impaired cardiac function upon extensive analysis of left ventricle function by echocardiography and pressure-volume relationships, while their parental SS/Mcwi experienced deterioration in function between 18 and 36 wk of age. In addition aging SS-16BN/Mcwi did not exhibit tissue remodeling common to pathological hypertrophy and HCM such as increased fibrosis and reduced capillary density in the myocardium. In fact, SS-16BN/Mcwi were better protected from developing LV fibrosis with age than either the hypertensive SS/Mcwi or normotensive BN parental strains. This suggests that a gene or genes on chromosome 16 may be involved with both blood pressure regulation and preservation of cardiac function with aging.
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Affiliation(s)
- A J Kriegel
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA
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Derumeaux G, Ichinose F, Raher MJ, Morgan JG, Coman T, Lee C, Cuesta JM, Thibault H, Bloch KD, Picard MH, Scherrer-Crosbie M. Myocardial alterations in senescent mice and effect of exercise training: a strain rate imaging study. Circ Cardiovasc Imaging 2008; 1:227-34. [PMID: 19808547 DOI: 10.1161/circimaging.107.745919] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Aging is accompanied by an alteration in myocardial contractility. However, its noninvasive detection is difficult. The effect of chronic exercise on this decrease is unknown. Murine models of senescence are increasingly used to test therapies in aging. We tested whether strain rate imaging detected left ventricular (LV) systolic dysfunction in aging mice and was able to assess a potential improvement after exercise. METHODS AND RESULTS Young (3 weeks), adult (2 to 3 months), and old (6 to 18 months) C57BL6 male mice underwent echocardiograms with strain rate imaging, either in sedentary conditions or before, 2 weeks and 4 weeks after chronic swimming. Hemodynamic parameters of LV function including maximal and end-systolic elastance were obtained before euthanizing. LV fibrosis was measured using Sirius red staining. Conventional echocardiography was unable to detect LV systolic dysfunction in old mice, whereas both systolic strain rate and load-independent hemodynamic parameters such as preload recruitable stroke work and end-systolic elastance were significantly decreased. Both strain rate and load-independent hemodynamic parameters normalized after 4 weeks of exercise. Both endocardial and epicardial fibrosis were increased in the LV of aging mice. Endocardial fibrosis decreased in exercised aged mice. CONCLUSIONS Strain rate noninvasively detects LV systolic dysfunction associated with aging in mice, whereas conventional echocardiography does not. Chronic exercise normalizes LV systolic function and decreases fibrosis in old mice. Strain rate imaging in mice may be a useful tool to monitor the effect of new therapeutic strategies preventing the myocardial dysfunction associated with aging.
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Belabbas H, Zalvidea S, Casellas D, Molès JP, Galbes O, Mercier J, Jover B. Contrasting effect of exercise and angiotensin II hypertension on in vivo and in vitro cardiac angiogenesis in rats. Am J Physiol Regul Integr Comp Physiol 2008; 295:R1512-8. [PMID: 18768771 DOI: 10.1152/ajpregu.00014.2008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cardiac vessel density (beta-actin immunolabeling) and angiogenic capacity of coronary artery explants (culture in collagen gel) was determined in hypertrophied heart obtained by exercise training (10 wk) or ANG II infusion for 10 days. A group of rats received ANG II the last 10 days of training. The heart weight index was similarly elevated after exercise, and ANG II-hypertension compared with controls (3.16 +/- 0.09 and 3.11 +/- 0.11 vs. 2.68 +/- 0.08 mg/g, respectively), whereas tail cuff pressure (TCP) increased only in sedentary rats infused with ANG II. Vessel density was increased by 36% in trained rats and reduced by 30% in ANG II-infused rats. The number of sprouts generated by coronary rings was reduced by 50% in ANG II-infused rats and increased by 50% in exercise trained rats compared with controls (35 +/- 4 and 113 +/- 5 vs. 71 +/- 1 sprouts per ring, respectively). Exercise-training partly prevented the hypertensive effect of ANG II (TCP of 141 +/- 5 mmHg), whereas heart weight index (3.66 +/- 0.06 mg/g body wt) was not lowered. Myocardial vessel density was normalized, and sprouting from coronary rings increased by 50% in trained rats infused with ANG II compared with sedentary normotensive rats. Cardiac VEGF (Western blot analysis) was higher in hypertensive rats and not affected by exercise. Facing a similar increase in cardiac mass, intense training, but not ANG II hypertension, is accompanied by an increase in vascular density of the heart. The effect of training is unlikely related to changes in resting VEGF and may represent enhanced angiogenic capacity of the coronary vascular bed.
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Affiliation(s)
- Hassiba Belabbas
- Groupe Rein et Hypertension Montpellier University, Montpellier, France
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Medeiro A, Vanzelli A, Rosa K, Irigoyen M, Brum P. Effect of exercise training and carvedilol treatment on cardiac function and structure in mice with sympathetic hyperactivity-induced heart failure. Braz J Med Biol Res 2008; 41:812-7. [DOI: 10.1590/s0100-879x2008000900012] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2007] [Accepted: 08/21/2008] [Indexed: 11/22/2022] Open
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Lakhan SE, Harle L. Cardiac fibrosis in the elderly, normotensive athlete: case report and review of the literature. Diagn Pathol 2008; 3:12. [PMID: 18353184 PMCID: PMC2277381 DOI: 10.1186/1746-1596-3-12] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2008] [Accepted: 03/19/2008] [Indexed: 11/18/2022] Open
Abstract
Background Cardiac fibrosis occurs with normal aging, but the extent of this process and its effect on cardiac function is unknown. Fibrosis in the nonhypertensive elderly patient is thought to be due to decreased degradation, and not increased deposition, of collagen. The cause of this decreased degradation is unknown. Athletes commonly develop cardiac hypertrophy, and recent evidence has linked long-term physical activity to the development of interstitial myocardial fibrosis. Whether this exercise-induced fibrosis occurs regularly, or only in genetically predisposed individuals, is unknown. Case presentation We present the case of an elderly, nonhypertensive athlete who died suddenly of sepsis. Autopsy demonstrated foci of fibrosis throughout the right and left ventricle and significant narrowing of the left ventricular cavity. The findings may be secondary to aging, athletic activity or an undiagnosed medical condition. Conclusion The true incidence and importance of age- and exercise-associated myocardial fibrosis is an area for future research.
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Affiliation(s)
- Shaheen E Lakhan
- Global Neuroscience Initiative Foundation, Los Angeles, CA, USA.
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Shefer G, Carmeli E, Rauner G, Yablonka-Reuveni Z, Benayahu D. Exercise running and tetracycline as means to enhance skeletal muscle stem cell performance after external fixation. J Cell Physiol 2008; 215:265-75. [PMID: 18064665 DOI: 10.1002/jcp.21306] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Prolonged limb immobilization, which is often the outcome of injury and illness, results in the atrophy of skeletal muscles. The basis of muscle atrophy needs to be better understood in order to allow development of effective countermeasures. The present study focused on determining whether skeletal muscle stem cells, satellite cells, are directly affected by long-term immobilization as well as on investigating the potential of pharmacological and physiological avenues to counterbalance atrophy-induced muscle deterioration. We used external fixation (EF), as a clinically relevant model, to gain insights into the relationships between muscle degenerative and regenerative conditions to the myogenic properties and abundance of bona fide satellite cells. Rats were treated with tetracycline (Tet) through the EF period, or exercise trained on a treadmill for 2 weeks after the cessation of the atrophic stimulus. EF induced muscle mass loss; declined expression of the muscle specific regulatory factors (MRFs) Myf5, MyoD, myogenin, and also of satellite cell numbers and myogenic differentiation aptitude. Tet enhanced the expression of MRFs, but did not prevent the decline of the satellite cell pool. After exercise running, however, muscle mass, satellite cell numbers (enumerated through the entire length of myofibers), and myogenic differentiation aptitude (determined by the lineal identity of clonal cultures of satellite cells) were re-gained to levels prior to EF. Together, our results point to Tet and exercise running as promising and relevant approaches for enhancing muscle recovery after atrophy.
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Affiliation(s)
- G Shefer
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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Spierer DK, DeMeersman RE, Kleinfeld J, McPherson E, Fullilove RE, Alba A, Zion AS. Exercise training improves cardiovascular and autonomic profiles in HIV. Clin Auton Res 2007; 17:341-8. [PMID: 18049834 DOI: 10.1007/s10286-007-0441-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2007] [Accepted: 08/06/2007] [Indexed: 11/29/2022]
Abstract
OBJECTIVES Human immunodeficiency virus (HIV) is associated with cardiovascular (CV) and autonomic dysfunction, however the effects of fitness on vascular and autonomic mechanisms in HIV disease are unknown. METHODS We studied forty-eight subjects (40.4 +/- 4.2 years) in a cross-sectional design matched for age, gender, BMI, and fitness. Participants were assigned to 1 in 4 groups: 1) Healthy Unfit (HU), 2) Healthy Fit (HF), 3) HIV Positive Unfit (HPU), and 4) HIV Positive Fit (HPF). Fitness was assessed via open-circuit spirometry; arterial compliance and autonomic modulations were measured via applanation tonometry and power spectral analysis, respectively, and baroreflex sensitivity was obtained using the alpha index. RESULTS Arterial compliance was augmented in HPF vs. HPU [7.4 +/- 1.9 mmHg x second vs. 4.4 +/- 1.7 mmHg x second (P = 0.006)]. Parasympathetic modulation was higher in HPF vs. HPU [2244.5 +/- 2997.6 msecond(2) vs. 489.1 +/- 552.9 msecond(2) (P < 0.05)]. Sympathetic modulation was lower in HPF vs. HU [4.7 +/- 5.0 mmHg(2) vs. 12.9 +/- 9.7 mmHg(2) (P < 0.05)]. Baroreflex sensitivity was higher in HPF vs. HPU [17.3 +/- 10.2 msecond/mmHg vs. 7.4 +/- 3.8 msecond/mmHg (P = 0.003)], and HPF vs. HU [17.3 +/- 10.2 msecond/mmHg vs. 6.2 +/- 3.0 msecond/mmHg (P = 0.004)]. CONCLUSIONS Augmentations in arterial compliance and baroreflex sensitivity associated with fitness portent an improved CV and autonomic profile for HIV-positive individuals. Physical activity may be an adjuvant method to enhance the overall vascular health in HIV-compromised individuals.
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Affiliation(s)
- David K Spierer
- Coler Goldwater Specialty Hospital and Nursing Facility, Roosevelt Island, NY, USA.
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Hwang HS, Cirrincione G, Thomas DP, McCormick RJ, Boluyt MO. Aldosterone Antagonism Fails to Attenuate Age-Associated Left Ventricular Fibrosis. J Gerontol A Biol Sci Med Sci 2007; 62:382-8. [PMID: 17452731 DOI: 10.1093/gerona/62.4.382] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Collagen accumulates disproportionately in cardiac remodeling induced by hypertension and associated with advancing age. Spironolactone (Spiro), an aldosterone antagonist, attenuates the accumulation of collagen induced by hypertension. It was hypothesized that Spiro would attenuate the age-associated increase in percent collagen in the heart. Female Fisher 344 rats at 3 months (Y), 12 months (M), and 21 months (O) of age were treated with Spiro (30 mg/kg/d) or vehicle (Veh) for 2 months, yielding six groups: Y-Veh, Y-Spiro, M-Veh, M-Spiro, O-Veh, and O-Spiro. Hearts were harvested for immunoblotting, RNA blotting, and biochemical analysis. Percent collagen in the left ventricle and septum was greatest in the oldest rats. Spiro did not significantly attenuate the age-associated increase in collagen fraction or the age-associated increases in expression of atrial natriuretic factor and beta-myosin heavy chain messenger RNA. Chronic aldosterone antagonism does not attenuate the age-associated increase in collagen fraction in the female Fisher 344 rat heart.
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Affiliation(s)
- Hyun Seok Hwang
- Division of Kinesiology, Laboratory of Molecular Kinesiology, University of Michigan, Ann Arbor, MI 48109-2214, USA
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Gates PE, Seals DR. Decline in large elastic artery compliance with age: a therapeutic target for habitual exercise. Br J Sports Med 2006; 40:897-9. [PMID: 16954129 PMCID: PMC2465023 DOI: 10.1136/bjsm.2004.016782] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- P E Gates
- School for Health, University of Bath, Bath BA2 7AY, UK.
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Boluyt MO, Cirrincione GM, Loyd AM, Korzick DH, Parker JL, Laughlin MH. Effects of gradual coronary artery occlusion and exercise training on gene expression in swine heart. Mol Cell Biochem 2006; 294:87-96. [PMID: 16937015 PMCID: PMC2662753 DOI: 10.1007/s11010-006-9248-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2005] [Accepted: 05/16/2006] [Indexed: 10/24/2022]
Abstract
Gradual occlusion (O) of the swine left circumflex coronary artery (LCX) with an ameroid occluder results in complete O within 3 weeks, collateral vessel development, and compensatory hypertrophy. The purpose of this investigation was to determine the independent and combined effects of O and exercise training (E) on gene expression in the swine heart. Adult Yucatan miniature swine were assigned to one of the following groups (n=6-9/group): sedentary control (S), exercise-trained (E), sedentary swine subjected to LCX occlusion (SO), and exercise-trained swine with LCX occlusion (EO). Exercise consisted of progressive treadmill running conducted 5 d/wk for 16 weeks. Gene expression was studied in myocardium isolated from the collateral-dependent left ventricle free wall (LV) and the collateral-independent septum (SEP) by RNA blotting. E and O each stimulated cardiac hypertrophy independently (p<0.001) with no interaction. O but not E increased atrial natriuretic factor expression in the LV, but not in the SEP. E decreased the expression of beta-myosin heavy chain in the LV, but not in the SEP. E retarded the expression of collagen III mRNA in SEP; but not in the LV. Exercise training and coronary artery occlusion each stimulate cardiac hypertrophy independently and induce different patterns of gene expression.
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Boluyt MO, Brevick JL, Rogers DS, Randall MJ, Scalia AF, Li ZB. Changes in the rat heart proteome induced by exercise training: Increased abundance of heat shock protein hsp20. Proteomics 2006; 6:3154-69. [PMID: 16586429 DOI: 10.1002/pmic.200401356] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Chronic exercise training elicits adaptations in the heart that improve pump function and confer cardioprotection. To identify molecular mechanisms by which exercise training stimulates this favorable phenotype, a proteomic approach was employed to detect rat cardiac proteins that were differentially expressed or modified after exercise training. Exercise-trained rats underwent six weeks of progressive treadmill training five days/week, 0% grade, using an interval training protocol. Sedentary control rats were age- and weight-matched to the exercise-trained rats. Hearts were harvested at various times (0-72 h) after the last bout of exercise and were used to generate 2-D electrophoretic proteome maps and immunoblots. Compared with hearts of sedentary rats, 26 protein spot intensities were significantly altered in hypertrophied hearts of exercise-trained rats (p <0.05), and 12 spots appeared exclusively on gels from hearts of exercise-trained rats. Immunoblotting confirmed that chronic exercise training, but not a single bout of exercise, elicited a 2.5-fold increase in the abundance of one of the candidate proteins in the heart, a 20 kDa heat shock protein (hsp20) that persisted for at least 72 h of detraining. Thus, exercise training alters the cardiac proteome of the rat heart; the changes include a marked increase in the expression of hsp20.
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Affiliation(s)
- Marvin O Boluyt
- Center for Exercise Research, Division of Kinesiology, The University of Michigan, Laboratory of Molecular Kinesiology, 401 Washtenaw Avenue, Ann Arbor, MI 48109, USA.
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Konhilas JP, Watson PA, Maass A, Boucek DM, Horn T, Stauffer BL, Luckey SW, Rosenberg P, Leinwand LA. Exercise can prevent and reverse the severity of hypertrophic cardiomyopathy. Circ Res 2006; 98:540-8. [PMID: 16439687 DOI: 10.1161/01.res.0000205766.97556.00] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Hypertrophic cardiomyopathy (HCM) is the most common form of sudden death in young competitive athletes. However, exercise has also been shown to be beneficial in the setting of other cardiac diseases. We examined the ability of voluntary exercise to prevent or reverse the phenotypes of a murine model of HCM harboring a mutant myosin heavy chain (MyHC). No differences in voluntary cage wheel performance between nontransgenic (NTG) and HCM male mice were seen. Exercise prevented fibrosis, myocyte disarray, and induction of "hypertrophic" markers including NFAT activity when initiated before established HCM pathology. If initiated in older HCM animals with documented disease, exercise reversed myocyte disarray (but not fibrosis) and "hypertrophic" marker induction. In addition, exercise returned the increased levels of phosphorylated GSK-3beta to those of NTG and decreased levels of phosphorylated CREB in HCM mice to normal levels. Exercise in HCM mice also favorably impacted components of the apoptotic signaling pathway, including Bcl-2 (an inhibitor of apoptosis) and procaspase-9 (an effector of apoptosis) expression, and caspase-3 activity. Remarkably, there were no differences in mortality between exercised NTG and HCM mice. Thus, not only was exercise not harmful but also it was able to prevent and even reverse established cardiac disease phenotypes in this HCM model.
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Affiliation(s)
- John P Konhilas
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309-0347, USA
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Eklund KE, Hageman KS, Poole DC, Musch TI. Impact of aging on muscle blood flow in chronic heart failure. J Appl Physiol (1985) 2005; 99:505-14. [PMID: 15802367 DOI: 10.1152/japplphysiol.00896.2004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Chronic heart failure (CHF) is manifested principally in the elderly population. Therefore, to understand the causes of exercise intolerance in CHF patients, it is imperative to resolve the effects of aging on muscle blood flow (BF) in CHF. To address this issue, we determined the muscle BF response to submaximal treadmill exercise (20 m/min, 5% grade) in young (Y(CHF): 6-8 mo, 412 +/- 11 g, n = 11) and old (O(CHF): 27-29 mo, 494 +/- 10 g, n = 8) Fischer 344 x Brown Norway rats with similar degrees of myocardial infarction-induced left ventricular (LV) dysfunction [resting LV end-diastolic pressure: Y(CHF) = 24 +/- 2, O(CHF) = 22 +/- 2 mmHg; derivative of LV pressure over time: Y(CHF) = 5,168 +/- 285; O(CHF) = 5,050 +/- 165 mmHg/s; lung weight normalized to body weight: Y(CHF) = 9.14 +/- 0.72; O(CHF) = 8.21 +/- 0.29 mg/g (all P > 0.05)]. The exercising heart rate response was blunted in O(CHF) compared with Y(CHF) rats (Y(CHF) = 454 +/- 8, O(CHF) = 395 +/- 9 beats/min; P < 0.05). BF (radiolabeled microspheres) to the total hindlimb musculature and to each of the 28 individual muscles examined was similar between Y(CHF) and O(CHF) rats under resting conditions. During exercise, BF to five of the hindlimb muscles that normally possess a majority of slow-twitch oxidative and fast-twitch oxidative glycolytic muscle fibers increased significantly less (-25 to -42%) for O(CHF) compared with Y(CHF) rats. In contrast, BF to 14 of the hindlimb muscles that normally possess a majority of fast-twitch glycolytic muscle fibers was increased (+22 to +337%) for O(CHF) vs. Y(CHF) rats, which contributed to a greater mass-specific total hindlimb BF response in O(CHF) rats (Y(CHF) = 78 +/- 5, O(CHF) = 100 +/- 11 ml.min(-1).100 g(-1); P < 0.05) and coincided with greater reductions in BF to the kidneys and splanchnic organs during exercise in O(CHF) vs. Y(CHF). In conclusion, there appears to be a profound age-related redistribution of BF from the highly oxidative to the highly glycolytic muscles of the hindlimb during exercise in O(CHF) compared with Y(CHF) rats. This phenomenon is qualitatively similar to that reported previously for healthy young and old rats.
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Affiliation(s)
- Kevin E Eklund
- Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, 128 Coles Hall, 1600 Denison Avenue, Manhattan, KS 66505-5802, USA
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Nottin S, Nguyen LD, Terbah M, Obert P. Long-term endurance training does not prevent the age-related decrease in left ventricular relaxation properties. ACTA ACUST UNITED AC 2004; 181:209-15. [PMID: 15180793 DOI: 10.1111/j.1365-201x.2004.01284.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
AIM Diastolic filling dynamics in the long-term endurance trained elderly has previously been examined by transmitral flow velocity, which has been shown to be preload dependent. The aim of this study was to assess the effect of long-term endurance training on left ventricular (LV) relaxation in older individuals by using pulsed tissue Doppler imaging. METHODS Fourteen master athletes with a history of intensive long-term endurance training, 14 aged-matched sedentary controls and 15 young adult men underwent standard Doppler echocardiography and pulsed Doppler tissue imaging, performed in four-chambers apical view, by placing a sample volume at the level of the mitral annulus. RESULTS Stroke volume was significantly higher and heart rate lower in master athletes compared with aged-matched sedentary subjects. Transmitral Peak E velocity and ratio E/A were significantly higher in master athletes, but did not reach the values of young men. Peak LV wall motion during the early filling phase, an index of LV relaxation, were significantly higher in young men than in both groups of older individuals. However, similar values were obtained between master athletes and sedentary counterparts. CONCLUSIONS Our data provide evidence that long-term training does not reduce the age-related decline in LV relaxation properties in humans. This finding implies that other mechanisms, such as increased LV filling pressures due to expanded blood volume, are probably responsible for the higher contribution of early diastolic filling to LV filling in master athletes compared with their sedentary counterparts. However this hypothesis needs to be confirmed.
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Affiliation(s)
- S Nottin
- Laboratory of Cardio-Vascular Adaptations to Exercise, Faculty of Sciences, 33 Rue Louis Pasteur, Avignon, France
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Pacher P, Mabley JG, Liaudet L, Evgenov OV, Marton A, Haskó G, Kollai M, Szabó C. Left ventricular pressure-volume relationship in a rat model of advanced aging-associated heart failure. Am J Physiol Heart Circ Physiol 2004; 287:H2132-7. [PMID: 15231502 PMCID: PMC2756475 DOI: 10.1152/ajpheart.00405.2004] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Aging is associated with profound changes in the structure and function of the heart. A fundamental understanding of these processes, using relevant animal models, is required for effective prevention and treatment of cardiovascular disease in the elderly. Here, we studied cardiac performance in 4- to 5-mo-old (young) and 24- to 26-mo-old (old) Fischer 344 male rats using the Millar pressure-volume (P-V) conductance catheter system. We evaluated systolic and diastolic function in vivo at different preloads, including preload recruitable stroke work (PRSW), maximal slope of the systolic pressure increment (+dP/dt), and its relation to end-diastolic volume (+dP/dt-EDV) as well as the time constant of left ventricular pressure decay, as an index of relaxation. The slope of the end-diastolic P-V relation (EDPVR), an index of left ventricular stiffness, was also calculated. Aging was associated with decrease in left ventricular systolic pressure, +dP/dt, maximal slope of the diastolic pressure decrement, +dP/dt-EDV, PRSW, ejection fraction, stroke volume, cardiac and stroke work indexes, and efficiency. In contrast, total peripheral resistance, left ventricular end-diastolic volume, left ventricular end-diastolic pressure, and EDPVR were greater in aging than in young animals. Taken together, these data suggest that advanced aging is characterized by decreased systolic performance accompanied by delayed relaxation and increased diastolic stiffness of the heart in male Fischer 344 rats. P-V analysis is a sensitive method to determine cardiac function in rats.
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Affiliation(s)
- Pál Pacher
- National Institute on Alcohol Abuse and Alcoholism, 12420 Parklawn Dr., MSC-8115, Bethesda, MD 20892-8115, USA.
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Chouabe C, Ricci E, Amsellem J, Blaineau S, Dalmaz Y, Favier R, Pequignot JM, Bonvallet R. Effects of aging on the cardiac remodeling induced by chronic high-altitude hypoxia in rat. Am J Physiol Heart Circ Physiol 2004; 287:H1246-53. [PMID: 15142847 DOI: 10.1152/ajpheart.00199.2004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Effects of chronic high-altitude hypoxia on the remodeling of right ventricle were examined in three age groups of rats: 2, 6, and 18 mo. The extent of right ventricular (RV) hypertrophy (RVH) showed an age-associated diminution. RV cell size and pericellular fibrosis showed a significant increase in the 2- and 6-mo-old exposed rats but not in the 18-mo-old exposed rats compared with control. A hyperplasic response was underscored in the three exposed age groups but appeared less pronounced in the 18-mo-old rats. A significant decrease in the transient outward potassium current (Ito) density was observed in RV cell only in the 2-mo-old exposed group compared with the control group. In the control group, there was a clear tendency for Ito density to decrease as a function of age. The sustained outward current density was modified neither by the hypoxia condition nor by the age. Neither the cytochrome c oxidase activity nor the heat shock protein 72 content in the RV was altered after hypoxic exposure regardless of age. The norepinephrine content in the RV was significantly decreased in each age group exposed to hypoxia when compared with their age-matched control group. Our findings indicate that the remodeling (at morphological and electrophysiological levels) induced by chronic hypoxia in the RV can be decreased by the natural aging process.
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Affiliation(s)
- C Chouabe
- Unité Mixte de Recherche Centre National de la Recherche Scientifique 5123, Physiologie Intégrative, Cellulaire et Moléculaire, Université Claude Bernard-Lyon I, 69622 Villeurbanne, France
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Tanabe A, Naruse M, Hara Y, Sato A, Tsuchiya K, Nishikawa T, Imaki T, Takano K. Aldosterone antagonist facilitates the cardioprotective effects of angiotensin receptor blockers in hypertensive rats. J Hypertens 2004; 22:1017-23. [PMID: 15097243 DOI: 10.1097/00004872-200405000-00025] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND There is increasing evidence to support the importance of blocking aldosterone to prevent target-organ damage in hypertension. We recently demonstrated an aldosterone breakthrough phenomenon during administration of an angiotensin type 1 receptor blocker (ARB). OBJECTIVE To elucidate the pathophysiological significance of residual aldosterone by investigating the influence of the aldosterone antagonist on the cardioprotective effects of the ARB in hypertensive rats. METHODS Injection vehicle alone, ARB (1.0 mg/kg per day candesartan by mouth), aldosterone antagonist (10 mg/kg per day spironolactone, subcutaneously), or combined treatment were administered to male stroke-prone spontaneously hypertensive rats for 24 weeks from the age of 4 weeks. Blood pressure, plasma angiotensin II and aldosterone concentrations, left ventricular weight, expression of type I and type III collagen mRNA, and histological findings were determined. RESULTS In the ARB-treated group, aldosterone concentrations remained unchanged (1.10 +/- 0.20 nmol/l, compared with 1.17 +/- 0.46 nmol/l in the control group), whereas systolic blood pressure (178 +/- 9 mmHg), left ventricular weight (0.372 +/- 0.035 g/100 g body weight), expression of collagen mRNA, and cardiac interstitial and perivascular fibrosis all decreased significantly compared with the control group (systolic blood pressure: 222 +/- 10 mmHg, P < 0.05; left ventricular weight: 0.483 +/- 0.021 g/100 g body weight, P < 0.05). Although blood pressure (217 +/- 9 mmHg) and left ventricular weight (0.467 +/- 0.027 g/100 g body weight) remained unchanged in the group receiving spironolactone, the expression of both types of collagen mRNA and cardiac interstitial and perivascular fibrosis showed a significant decrease compared with the vehicle-treated group. In the rats receiving combined treatment with the ARB and spironolactone, left ventricular weight (0.352 +/- 0.005 g/100 g body weight, P < 0.05), expression of collagen mRNA, and cardiac interstitial and perivascular fibrosis all showed a further improvement compared with both the ARB and spironolactone groups. CONCLUSIONS These results demonstrate that residual aldosterone has a significant impact on target-organ damage in hypertension, even during chronic administration of an ARB. The addition of an aldosterone antagonist has an advantage in facilitating the cardioprotective effects of ARBs.
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Affiliation(s)
- Akiyo Tanabe
- Department of Medicine, Institute of Clinical Endocrinology, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan.
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Kjaer M. Role of extracellular matrix in adaptation of tendon and skeletal muscle to mechanical loading. Physiol Rev 2004; 84:649-98. [PMID: 15044685 DOI: 10.1152/physrev.00031.2003] [Citation(s) in RCA: 953] [Impact Index Per Article: 47.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The extracellular matrix (ECM), and especially the connective tissue with its collagen, links tissues of the body together and plays an important role in the force transmission and tissue structure maintenance especially in tendons, ligaments, bone, and muscle. The ECM turnover is influenced by physical activity, and both collagen synthesis and degrading metalloprotease enzymes increase with mechanical loading. Both transcription and posttranslational modifications, as well as local and systemic release of growth factors, are enhanced following exercise. For tendons, metabolic activity, circulatory responses, and collagen turnover are demonstrated to be more pronounced in humans than hitherto thought. Conversely, inactivity markedly decreases collagen turnover in both tendon and muscle. Chronic loading in the form of physical training leads both to increased collagen turnover as well as, dependent on the type of collagen in question, some degree of net collagen synthesis. These changes will modify the mechanical properties and the viscoelastic characteristics of the tissue, decrease its stress, and likely make it more load resistant. Cross-linking in connective tissue involves an intimate, enzymatical interplay between collagen synthesis and ECM proteoglycan components during growth and maturation and influences the collagen-derived functional properties of the tissue. With aging, glycation contributes to additional cross-linking which modifies tissue stiffness. Physiological signaling pathways from mechanical loading to changes in ECM most likely involve feedback signaling that results in rapid alterations in the mechanical properties of the ECM. In developing skeletal muscle, an important interplay between muscle cells and the ECM is present, and some evidence from adult human muscle suggests common signaling pathways to stimulate contractile and ECM components. Unaccostumed overloading responses suggest an important role of ECM in the adaptation of myofibrillar structures in adult muscle. Development of overuse injury in tendons involve morphological and biochemical changes including altered collagen typing and fibril size, hypervascularization zones, accumulation of nociceptive substances, and impaired collagen degradation activity. Counteracting these phenomena requires adjusted loading rather than absence of loading in the form of immobilization. Full understanding of these physiological processes will provide the physiological basis for understanding of tissue overloading and injury seen in both tendons and muscle with repetitive work and leisure time physical activity.
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Affiliation(s)
- Michael Kjaer
- Sports Medicine Research Unit, Department of Rheumatology, Copenhagen University Hospital at Bispebjerg, 23 Bispebjerg Bakke, DK-2400 Copenhagen NV, Denmark.
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McMullen JR, Shioi T, Huang WY, Zhang L, Tarnavski O, Bisping E, Schinke M, Kong S, Sherwood MC, Brown J, Riggi L, Kang PM, Izumo S. The insulin-like growth factor 1 receptor induces physiological heart growth via the phosphoinositide 3-kinase(p110alpha) pathway. J Biol Chem 2003; 279:4782-93. [PMID: 14597618 DOI: 10.1074/jbc.m310405200] [Citation(s) in RCA: 298] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Insulin-like growth factor 1 (IGF1) was considered a potential candidate for the treatment of heart failure. However, some animal studies and clinical trials have questioned whether elevating IGF1 chronically is beneficial. Secondary effects of increased serum IGF1 levels on other tissues may explain these unfavorable results. The aim of the current study was to examine the role of IGF1 in cardiac myocytes in the absence of secondary effects, and to elucidate downstream signaling pathways and transcriptional regulatory effects of the IGF1 receptor (IGF1R). Transgenic mice overexpressing IGF1R in the heart displayed cardiac hypertrophy, which was the result of an increase in myocyte size, and there was no evidence of histopathology. IGF1R transgenics also displayed enhanced systolic function at 3 months of age, and this was maintained at 12-16 months of age. The phosphoinositide 3-kinase (PI3K)-Akt-p70S6K1 pathway was significantly activated in hearts from IGF1R transgenics. Cardiac hypertrophy induced by overexpression of IGF1R was completely blocked by a dominant negative PI3K(p110alpha) mutant, suggesting IGF1R promotes compensated cardiac hypertrophy in a PI3K(p110alpha)-dependent manner. This study suggests that targeting the cardiac IGF1R-PI3K(p110alpha) pathway could be a potential therapeutic strategy for the treatment of heart failure.
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Affiliation(s)
- Julie R McMullen
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA.
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Boluyt MO, Converso K, Hwang HS, Mikkor A, Russell MW. Echocardiographic assessment of age-associated changes in systolic and diastolic function of the female F344 rat heart. J Appl Physiol (1985) 2003; 96:822-8. [PMID: 14555689 DOI: 10.1152/japplphysiol.01026.2003] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Aging is associated with hypertrophy, dilatation, and fibrosis of the left ventricle (LV) of the heart. Advances in echocardiographic assessment have made it possible to follow changes in cardiac function in a serial, noninvasive manner. The purpose was to determine whether there is echocardiographic evidence of age-associated changes in chamber dimensions and systolic and diastolic properties of the female Fischer 344 (F344) rat heart. On the basis of previous invasive studies, it was predicted that echocardiographic assessment would detect age-associated changes in indexes of systolic and diastolic function. Rats were sedated with 1.5% isoflurane and placed in the supine position. Two-dimensional images and two-dimensionally guided M-mode, Doppler M mode, Doppler tissue, and pulsed-wave Doppler recordings were obtained from the parasternal long axis, parasternal short axis, and/or apical four-chamber views as per convention by using a 15-MHz linear array or 8-MHz phased-array transducer or a GE S10-MHz phased-array transducer. Compared with young adult 4-mo-old rats, there is a significant decrement in the resting systolic function of the LV in 30-mo-old female F344 rats as evidenced by declines in LV ejection fraction (80 +/- 9 vs. 89 +/- 5%; mean +/- SD), fractional shortening (43 +/- 9 vs. 54 +/- 8%) and velocity of circumferential fiber shortening (2.43 +/- 0.53 vs. 2.99 +/- 0.50 circ/s). Evidence for age-associated differences in diastolic function included an increase in isovolumic relaxation time (25.0 +/- 7.6 vs. 17.2 +/- 4.4 ms) and decreases in the tissue Doppler peak E waves at the septal annulus and at the lateral annulus of the mitral valve. The modest changes in systolic and diastolic LV function that occur with advancing age in the female F344 rat are likely to reduce the capacity of the heart to respond to hemodynamic challenges.
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Affiliation(s)
- Marvin O Boluyt
- Division of Kinesiology, Laboratory of Molecular Kinesiology, The University of Michigan, Ann Arbor, Michigan 48109-2214, USA.
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Fenning A, Harrison G, Dwyer D, Rose'Meyer R, Brown L. Cardiac adaptation to endurance exercise in rats. Mol Cell Biochem 2003; 251:51-9. [PMID: 14575304 DOI: 10.1007/978-1-4419-9238-3_8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Endurance exercise is widely assumed to improve cardiac function in humans. This project has determined cardiac function following endurance exercise for 6 (n = 30) or 12 (n = 25) weeks in male Wistar rats (8 weeks old). The exercise protocol was 30 min/day at 0.8 km/h for 5 days/week with an endurance test on the 6th day by running at 1.2 km/h until exhaustion. Exercise endurance increased by 318% after 6 weeks and 609% after 12 weeks. Heart weight/kg body weight increased by 10.2% after 6 weeks and 24.1% after 12 weeks. Echocardiography after 12 weeks showed increases in left ventricular internal diameter in diastole (6.39 +/- 0.32 to 7.90 +/- 0.17 mm), systolic volume (49 +/- 7 to 83 +/- 11 miccrol) and cardiac output (75 +/- 3 to 107 +/- 8 ml/min) but not left wall thickness in diastole (1.74 +/- 0.07 to 1.80 +/- 0.06 mm). Isolated Langendorff hearts from trained rats displayed decreased left ventricular myocardial stiffness (22 +/- 1.1 to 19.1 +/- 0.3) and reduced purine efflux during pacing-induced workload increases. 31P-NMR spectroscopy in isolated hearts from trained rats showed decreased PCr and PCr/ATP ratios with increased creatine, AMP and ADP concentrations. Thus, this endurance exercise protocol resulted in physiological hypertrophy while maintaining or improving cardiac function.
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Affiliation(s)
- Andrew Fenning
- Department of Physiology and Pharmacology, School of Biomedical Sciences, The University of Queensland, Australia
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Abstract
We review the macroscopic and microscopic anatomy of myocardial disease associated with heart failure (HF) and sudden cardiac death (SCD) and focus on the prevention of SCD in light of its structural pathways. Compared to patients without SCD, patients with SCD exhibit 5- to 6-fold increases in the risks of ventricular arrhythmias and SCD. Epidemiologically, left ventricular hypertrophy by ECG or echocardiography acts as a potent dose-dependent SCD predictor. Dyslipidemia, a coronary disease risk factor, independently predicts echocardiographic hypertrophy. In adult SCD autopsy studies, increases in heart weight and severe coronary disease are constant findings, whereas rates of acute coronary thrombi vary remarkably. The microscopic myocardial anatomy of SCD is incompletely defined but may include prevalent changes of advanced myocardial disease, including cardiomyocyte hypertrophy, cardiomyocyte apoptosis, fibroblast hyperplasia, diffuse and focal matrix protein accumulation, and recruitment of inflammatory cells. Hypertrophied cardiomyocytes express "fetospecific" genetic programs that can account for acquired long QT physiology with risk for polymorphic ventricular arrhythmias. Structural heart disease associated with HF and high SCD risk is causally related to an up-regulation of the adrenergic renin-angiotensin-aldosterone pathway. In outcome trials, suppression of this pathway with combinations of beta-blockers, angiotensin-converting enzyme inhibitors, angiotensin-II receptor blockers, and mineralocorticoid receptor blockers have achieved substantial total mortality and SCD reductions. Contrarily, trials with ion channel-active agents that are not known to reduce structural heart disease have failed to reduce these risks. Device therapy effectively prevents SCD, but whether biventricular pacing-induced remodeling decreases left ventricular mass remains uncertain.
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MESH Headings
- Animals
- Anti-Arrhythmia Agents/therapeutic use
- Apoptosis
- Cardiac Output, Low/drug therapy
- Cardiac Output, Low/etiology
- Cardiac Output, Low/pathology
- Cardiac Output, Low/physiopathology
- Cardiac Output, Low/prevention & control
- Cardiomegaly/complications
- Cardiomegaly/physiopathology
- Coronary Artery Disease/complications
- Coronary Artery Disease/physiopathology
- Death, Sudden, Cardiac/etiology
- Death, Sudden, Cardiac/prevention & control
- Heart Diseases/complications
- Heart Diseases/pathology
- Heart Diseases/physiopathology
- Humans
- Mitosis
- Myocytes, Cardiac/metabolism
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Affiliation(s)
- Antonio Pacifico
- Texas Arrhythmia Institute and Baylor College of Medicine, Scorlock Tower, Suite 620, 6560 Fannin Street, Houston, TX 77030, USA.
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