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Wang Q, Cui C, Zhang N, Lin W, Chai S, Chow SKH, Wong RMY, Hu Y, Law SW, Cheung WH. Effects of physical exercise on neuromuscular junction degeneration during ageing: A systematic review. J Orthop Translat 2024; 46:91-102. [PMID: 38817243 PMCID: PMC11137388 DOI: 10.1016/j.jot.2024.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 03/27/2024] [Accepted: 03/31/2024] [Indexed: 06/01/2024] Open
Abstract
The neuromuscular junction (NMJ) is a specialized chemical synapse that converts neural impulses into muscle action. Age-associated NMJ degeneration, which involves nerve terminal and postsynaptic decline, denervation, and loss of motor units, significantly contributes to muscle weakness and dysfunction. Although physical training has been shown to make substantial modifications in NMJ of both young and aged animals, the results are often influenced by methodological variables in existing studies. Moreover, there is still lack of strong consensus on the specific effects of exercise on improving the morphology and function of the ageing NMJ. Consequently, the purpose of this study was to conduct a systematic review to elucidate the effects of exercise training on NMJ compartments in the elderly. We conducted a systematic review using PubMed, Embase, and Web of Science databases, employing relevant keywords. Two independent reviewers selected studies that detailed NMJ changes during exercise in ageing, written in English, and available in full text. In total, 20 papers were included. We examined the altered adaptation of the NMJ to exercise, focusing on presynaptic and postsynaptic structures and myofibers in older animals or humans. Our findings indicated that aged NMJs exhibited different adaptive responses to physical exercise compared to younger counterparts. Endurance training, compared with resistance and voluntary exercise regimens, was found to have a more pronounced effect on NMJ structural remodeling, particularly in fast twitch muscle fibers. Physical exercise was observed to promote the formation and maintenance of acetylcholine receptor (AChR) clusters by increasing the recombinant docking protein 7 (Dok7) expression and stabilizing Agrin and lipoprotein receptor-related protein 4 (LRP4). These insights suggest that research on exercise-related therapies could potentially attenuate the progression of neuromuscular degeneration. Translational potential of this article: This systematic review provides a detailed overview of the effects of different types of physical exercise on improving NMJ in the elderly, providing scientific support for the timely intervention of muscle degeneration in the elderly by physical exercise, and providing help for the development of new therapeutic interventions in the future.
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Affiliation(s)
- Qianjin Wang
- Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
- Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
| | - Can Cui
- Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
- Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
| | - Ning Zhang
- Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
- Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
| | - Wujian Lin
- Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
- Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
| | - Senlin Chai
- Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
- Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
| | - Simon Kwoon-Ho Chow
- Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
- Department of Orthopaedic Surgery, Stanford University, Stanford, CA, USA
| | - Ronald Man Yeung Wong
- Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
| | - Yong Hu
- Department of Orthopaedics and Traumatology, The University of Hong Kong, Hong Kong Special Administrative Region of China
| | - Sheung Wai Law
- Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
| | - Wing-Hoi Cheung
- Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
- Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
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Sturm G, Karan KR, Monzel AS, Santhanam B, Taivassalo T, Bris C, Ware SA, Cross M, Towheed A, Higgins-Chen A, McManus MJ, Cardenas A, Lin J, Epel ES, Rahman S, Vissing J, Grassi B, Levine M, Horvath S, Haller RG, Lenaers G, Wallace DC, St-Onge MP, Tavazoie S, Procaccio V, Kaufman BA, Seifert EL, Hirano M, Picard M. OxPhos defects cause hypermetabolism and reduce lifespan in cells and in patients with mitochondrial diseases. Commun Biol 2023; 6:22. [PMID: 36635485 PMCID: PMC9837150 DOI: 10.1038/s42003-022-04303-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 11/26/2022] [Indexed: 01/13/2023] Open
Abstract
Patients with primary mitochondrial oxidative phosphorylation (OxPhos) defects present with fatigue and multi-system disorders, are often lean, and die prematurely, but the mechanistic basis for this clinical picture remains unclear. By integrating data from 17 cohorts of patients with mitochondrial diseases (n = 690) we find evidence that these disorders increase resting energy expenditure, a state termed hypermetabolism. We examine this phenomenon longitudinally in patient-derived fibroblasts from multiple donors. Genetically or pharmacologically disrupting OxPhos approximately doubles cellular energy expenditure. This cell-autonomous state of hypermetabolism occurs despite near-normal OxPhos coupling efficiency, excluding uncoupling as a general mechanism. Instead, hypermetabolism is associated with mitochondrial DNA instability, activation of the integrated stress response (ISR), and increased extracellular secretion of age-related cytokines and metabokines including GDF15. In parallel, OxPhos defects accelerate telomere erosion and epigenetic aging per cell division, consistent with evidence that excess energy expenditure accelerates biological aging. To explore potential mechanisms for these effects, we generate a longitudinal RNASeq and DNA methylation resource dataset, which reveals conserved, energetically demanding, genome-wide recalibrations. Taken together, these findings highlight the need to understand how OxPhos defects influence the energetic cost of living, and the link between hypermetabolism and aging in cells and patients with mitochondrial diseases.
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Affiliation(s)
- Gabriel Sturm
- Department of Psychiatry, Division of Behavioral Medicine, Columbia University Irving Medical Center, New York, NY, USA
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA, USA
| | - Kalpita R Karan
- Department of Psychiatry, Division of Behavioral Medicine, Columbia University Irving Medical Center, New York, NY, USA
| | - Anna S Monzel
- Department of Psychiatry, Division of Behavioral Medicine, Columbia University Irving Medical Center, New York, NY, USA
| | - Balaji Santhanam
- Departments of Biological Sciences, Systems Biology, and Biochemistry and Molecular Biophysics, Institute for Cancer Dynamics, Columbia University, New York, NY, USA
| | - Tanja Taivassalo
- Department of Physiology and Functional Genomics, Clinical and Translational Research Building, University of Florida, Gainesville, FL, USA
| | - Céline Bris
- Department of Genetics and Neurology, Angers Hospital, Angers, France
- UMR CNRS 6015, INSERM U1083, MITOVASC, SFR ICAT, Université d'Angers, Angers, France
| | - Sarah A Ware
- Department of Medicine, Vascular Medicine Institute and Center for Metabolic and Mitochondrial Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Marissa Cross
- Department of Psychiatry, Division of Behavioral Medicine, Columbia University Irving Medical Center, New York, NY, USA
| | - Atif Towheed
- Department of Psychiatry, Division of Behavioral Medicine, Columbia University Irving Medical Center, New York, NY, USA
- Internal Medicine-Pediatrics Residency Program, University of Pittsburgh Medical Centre, Pittsburgh, PA, USA
| | - Albert Higgins-Chen
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
| | - Meagan J McManus
- Department of Anesthesiology and Critical Care Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Center for Mitochondrial and Epigenomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Andres Cardenas
- Department of Epidemiology and Population Health, Stanford University, Stanford, CA, USA
| | - Jue Lin
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA, USA
| | - Elissa S Epel
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, CA, USA
| | - Shamima Rahman
- Mitochondrial Research Group, UCL Great Ormond Street Institute of Child Health, and Metabolic Unit, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - John Vissing
- Copenhagen Neuromuscular Center, Department of Neurology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Bruno Grassi
- Department of Medicine, University of Udine, Udine, Italy
| | | | | | - Ronald G Haller
- Neuromuscular Center, Institute for Exercise and Environmental Medicine of Texas Health Resources and Department of Neurology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Guy Lenaers
- Department of Genetics and Neurology, Angers Hospital, Angers, France
- UMR CNRS 6015, INSERM U1083, MITOVASC, SFR ICAT, Université d'Angers, Angers, France
| | - Douglas C Wallace
- Center for Mitochondrial and Epigenomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Marie-Pierre St-Onge
- Center of Excellence for Sleep & Circadian Research and Division of General Medicine, Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
| | - Saeed Tavazoie
- Departments of Biological Sciences, Systems Biology, and Biochemistry and Molecular Biophysics, Institute for Cancer Dynamics, Columbia University, New York, NY, USA
| | - Vincent Procaccio
- Department of Genetics and Neurology, Angers Hospital, Angers, France
- UMR CNRS 6015, INSERM U1083, MITOVASC, SFR ICAT, Université d'Angers, Angers, France
| | - Brett A Kaufman
- Department of Medicine, Vascular Medicine Institute and Center for Metabolic and Mitochondrial Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Erin L Seifert
- Department of Pathology and Genomic Medicine, and MitoCare Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - Michio Hirano
- Department of Neurology, H. Houston Merritt Center, Columbia Translational Neuroscience Initiative, Columbia University Irving Medical Center, New York, NY, USA
| | - Martin Picard
- Department of Psychiatry, Division of Behavioral Medicine, Columbia University Irving Medical Center, New York, NY, USA.
- Department of Neurology, H. Houston Merritt Center, Columbia Translational Neuroscience Initiative, Columbia University Irving Medical Center, New York, NY, USA.
- New York State Psychiatric Institute, New York, NY, USA.
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Exercise Testing, Physical Training and Fatigue in Patients with Mitochondrial Myopathy Related to mtDNA Mutations. J Clin Med 2021; 10:jcm10081796. [PMID: 33924201 PMCID: PMC8074604 DOI: 10.3390/jcm10081796] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 04/06/2021] [Accepted: 04/08/2021] [Indexed: 01/05/2023] Open
Abstract
Mutations in mitochondrial DNA (mtDNA) cause disruption of the oxidative phosphorylation chain and impair energy production in cells throughout the human body. Primary mitochondrial disorders due to mtDNA mutations can present with symptoms from adult-onset mono-organ affection to death in infancy due to multi-organ involvement. The heterogeneous phenotypes that patients with a mutation of mtDNA can present with are thought, at least to some extent, to be a result of differences in mtDNA mutation load among patients and even among tissues in the individual. The most common symptom in patients with mitochondrial myopathy (MM) is exercise intolerance. Since mitochondrial function can be assessed directly in skeletal muscle, exercise studies can be used to elucidate the physiological consequences of defective mitochondria due to mtDNA mutations. Moreover, exercise tests have been developed for diagnostic purposes for mitochondrial myopathy. In this review, we present the rationale for exercise testing of patients with MM due to mutations in mtDNA, evaluate the diagnostic yield of exercise tests for MM and touch upon how exercise tests can be used as tools for follow-up to assess disease course or effects of treatment interventions.
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Abstract
Metabolic myopathies are muscle disorders caused by a biochemical defect of the skeletal muscle energy system resulting in exercise intolerance. The primary aim of this research was to evaluate the oxygen cost (∆V’O2/∆Work-Rate) during incremental exercise in patients with metabolic myopathies as compared with patients with non-metabolic myalgia and healthy subjects. The study groups consisted of eight patients with muscle glycogenoses (one Tarui and seven McArdle diseases), seven patients with a complete and twenty-two patients with a partial myoadenylate deaminase (MAD) deficiency in muscle biopsy, five patients with a respiratory chain deficiency, seventy-three patients with exercise intolerance and normal muscle biopsy (non-metabolic myalgia), and twenty-eight healthy controls. The subjects underwent a cardiopulmonary exercise test (CPX Medgraphics) performed on a bicycle ergometer. Pulmonary V’O2 was measured breath-by-breath throughout the incremental test. The ∆V’O2/∆Work-Rate slope for exercise was determined by linear regression analysis. Lower oxygen consumption (peak percent of predicted, mean ± SD; p < 0.04, one-way ANOVA) was seen in patients with glycogenoses (62.8 ± 10.2%) and respiratory chain defects (70.8 ± 23.3%) compared to patients with non-metabolic myalgia (100.0 ± 15.9%) and control subjects (106.4 ± 23.5%). ∆V’O2/∆Work-Rate slope (mLO2.min−1.W−1) was increased in patients with MAD absent (12.6 ± 1.5), MAD decreased (11.3 ± 1.1), glycogenoses (14.0 ± 2.5), respiratory chain defects (13.1 ± 1.2), and patients with non-metabolic myalgia (11.3 ± 1.3) compared with control subjects (10.2 ± 0.7; p < 0.001, one-way ANOVA). In conclusion, patients with metabolic myopathies display an increased oxygen cost during exercise and therefore can perform less work for a given VO2 consumption during daily life-submaximal exercises.
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5
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Cade WT, Bohnert KL, Peterson LR, Patterson BW, Bittel AJ, Okunade AL, de las Fuentes L, Steger-May K, Bashir A, Schweitzer GG, Chacko SK, Wanders RJ, Pacak CA, Byrne BJ, Reeds DN. Blunted fat oxidation upon submaximal exercise is partially compensated by enhanced glucose metabolism in children, adolescents, and young adults with Barth syndrome. J Inherit Metab Dis 2019; 42:480-493. [PMID: 30924938 PMCID: PMC6483838 DOI: 10.1002/jimd.12094] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 03/27/2019] [Indexed: 12/26/2022]
Abstract
Barth syndrome (BTHS) is a rare X-linked condition resulting in abnormal mitochondria, cardioskeletal myopathy, and growth delay; however, the effects of BTHS on substrate metabolism regulation and their relationships with tissue function in humans are unknown. We sought to characterize glucose and fat metabolism during rest, submaximal exercise, and postexercise rest in children, adolescents, and young adults with BTHS and unaffected controls and examine their relationships with cardioskeletal energetics and function. Children/adolescents and young adults with BTHS (n = 29) and children/adolescent and young adult control participants (n = 28, total n = 57) underwent an infusion of 6'6'H2 glucose and U-13 C palmitate and indirect calorimetry during rest, 30-minutes of moderate exercise (50% V˙O2peak ), and recovery. Cardiac function, cardioskeletal mitochondrial energetics, and exercise capacity were examined via echocardiography, 31 P magnetic resonance spectroscopy, and peak exercise testing, respectively. The glucose turnover rate was significantly higher in individuals with BTHS during rest (33.2 ± 9.8 vs 27.2 ± 8.1 μmol/kgFFM/min, P < .01) and exercise (34.7 ± 11.2 vs 29.5 ± 8.8 μmol/kgFFM/min, P < .05) and tended to be higher postexercise (33.7 ± 10.2 vs 28.8 ± 8.0 μmol/kgFFM/min, P < .06) compared to controls. Increases in total fat (-3.9 ± 7.5 vs 10.5 ± 8.4 μmol/kgFFM/min, P < .0001) and plasma fatty acid oxidation rates (0.0 ± 1.8 vs 5.1 ± 3.9 μmol/kgFFM/min, P < .0001) from rest to exercise were severely blunted in BTHS compared to controls. Conclusion: An inability to upregulate fat metabolism during moderate intensity exercise appears to be partially compensated by elevations in glucose metabolism. Derangements in fat and glucose metabolism are characteristic of the pathophysiology of BTHS. A severely blunted ability to upregulate fat metabolism during a modest level of physical activity is a defining pathophysiologic characteristic in children, adolescents, and young adults with BTHS.
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Affiliation(s)
- W. Todd Cade
- Program in Physical Therapy, 4444 Forest Park Avenue, Washington University School of Medicine, St. Louis, MO
- Department of Medicine, Washington University School of Medicine, St. Louis, MO
| | - Kathryn L. Bohnert
- Program in Physical Therapy, 4444 Forest Park Avenue, Washington University School of Medicine, St. Louis, MO
| | - Linda R. Peterson
- Department of Medicine, Washington University School of Medicine, St. Louis, MO
| | - Bruce W. Patterson
- Department of Medicine, Washington University School of Medicine, St. Louis, MO
| | - Adam J. Bittel
- Program in Physical Therapy, 4444 Forest Park Avenue, Washington University School of Medicine, St. Louis, MO
| | - Adewole L. Okunade
- Department of Medicine, Washington University School of Medicine, St. Louis, MO
| | - Lisa de las Fuentes
- Department of Medicine, Washington University School of Medicine, St. Louis, MO
| | - Karen Steger-May
- Division of Biostatistics, Washington University School of Medicine, St. Louis, MO
| | - Adil Bashir
- Department of Radiology, Washington University School of Medicine, St. Louis, MO
- Department of Electrical and Computer Engineering, Auburn University, Auburn, AL
| | | | - Shaji K. Chacko
- Department of Pediatrics, Baylor College of Medicine, Houston, TX
| | - Ronald J. Wanders
- Department of Pediatrics, University of Amsterdam, Amsterdam, The Netherlands
| | | | - Barry J Byrne
- Department of Pediatrics, University of Florida, Gainesville, FL
| | - Dominic N. Reeds
- Department of Medicine, Washington University School of Medicine, St. Louis, MO
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Gehrig SM, Mihaylova V, Frese S, Mueller SM, Ligon-Auer M, Spengler CM, Petersen JA, Lundby C, Jung HH. Altered skeletal muscle (mitochondrial) properties in patients with mitochondrial DNA single deletion myopathy. Orphanet J Rare Dis 2016; 11:105. [PMID: 27473873 PMCID: PMC4966582 DOI: 10.1186/s13023-016-0488-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 07/21/2016] [Indexed: 12/13/2022] Open
Abstract
Background Mitochondrial myopathy severely affects skeletal muscle structure and function resulting in defective oxidative phosphorylation. However, the major pathomechanisms and therewith effective treatment approaches remain elusive. Therefore, the aim of the present study was to investigate disease-related impairments in skeletal muscle properties in patients with mitochondrial myopathy. Accordingly, skeletal muscle biopsies were obtained from six patients with moleculargenetically diagnosed mitochondrial myopathy (one male and five females, 53 ± 9 years) and eight age- and gender-matched healthy controls (two males and six females, 58 ± 14 years) to determine mitochondrial respiratory capacity of complex I-V, mitochondrial volume density and fiber type distribution. Results Mitochondrial volume density (4.0 ± 0.5 vs. 5.1 ± 0.8 %) as well as respiratory capacity of complex I-V were lower (P < 0.05) in mitochondrial myopathy and associated with a higher (P < 0.001) proportion of type II fibers (65.2 ± 3.6 vs. 44.3 ± 5.9 %). Additionally, mitochondrial volume density and maximal oxidative phosphorylation capacity correlated positively (P < 0.05) to peak oxygen uptake. Conclusion Mitochondrial myopathy leads to impaired mitochondrial quantity and quality and a shift towards a more glycolytic skeletal muscle phenotype.
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Affiliation(s)
- Saskia Maria Gehrig
- Department of Neurology, University Hospital Zurich, Frauenklinikstrasse 26, 8091, Zurich, Switzerland.,Institute of Physiology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.,Zurich Center for Integrative Human Physiology (ZIHP), Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Violeta Mihaylova
- Department of Neurology, University Hospital Zurich, Frauenklinikstrasse 26, 8091, Zurich, Switzerland
| | - Sebastian Frese
- Department of Neurology, University Hospital Zurich, Frauenklinikstrasse 26, 8091, Zurich, Switzerland
| | - Sandro Manuel Mueller
- Department of Neurology, University Hospital Zurich, Frauenklinikstrasse 26, 8091, Zurich, Switzerland
| | - Maria Ligon-Auer
- Department of Neurology, University Hospital Zurich, Frauenklinikstrasse 26, 8091, Zurich, Switzerland
| | - Christina M Spengler
- Zurich Center for Integrative Human Physiology (ZIHP), Winterthurerstrasse 190, 8057, Zurich, Switzerland.,Exercise Physiology Lab, Institute of Human Movement Sciences, ETH Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Jens A Petersen
- Department of Neurology, University Hospital Zurich, Frauenklinikstrasse 26, 8091, Zurich, Switzerland
| | - Carsten Lundby
- Institute of Physiology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.,Zurich Center for Integrative Human Physiology (ZIHP), Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Hans H Jung
- Department of Neurology, University Hospital Zurich, Frauenklinikstrasse 26, 8091, Zurich, Switzerland. .,Zurich Center for Integrative Human Physiology (ZIHP), Winterthurerstrasse 190, 8057, Zurich, Switzerland.
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Morris G, Maes M. Mitochondrial dysfunctions in myalgic encephalomyelitis/chronic fatigue syndrome explained by activated immuno-inflammatory, oxidative and nitrosative stress pathways. Metab Brain Dis 2014; 29:19-36. [PMID: 24557875 DOI: 10.1007/s11011-013-9435-x] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2013] [Accepted: 08/22/2013] [Indexed: 02/07/2023]
Abstract
Myalgic encephalomyelitis/chronic fatigue syndrome (ME/cfs) is classified by the World Health Organization as a disorder of the central nervous system. ME/cfs is an neuro-immune disorder accompanied by chronic low-grade inflammation, increased levels of oxidative and nitrosative stress (O&NS), O&NS-mediated damage to fatty acids, DNA and proteins, autoimmune reactions directed against neoantigens and brain disorders. Mitochondrial dysfunctions have been found in ME/cfs, e.g. lowered ATP production, impaired oxidative phosphorylation and mitochondrial damage. This paper reviews the pathways that may explain mitochondrial dysfunctions in ME/cfs. Increased levels of pro-inflammatory cytokines, such as interleukin-1 and tumor necrosis factor-α, and elastase, and increased O&NS may inhibit mitochondrial respiration, decrease the activities of the electron transport chain and mitochondrial membrane potential, increase mitochondrial membrane permeability, interfere with ATP production and cause mitochondrial shutdown. The activated O&NS pathways may additionally lead to damage of mitochondrial DNA and membranes thus decreasing membrane fluidity. Lowered levels of antioxidants, zinc and coenzyme Q10, and ω3 polyunsaturated fatty acids in ME/cfs may further aggravate the activated immuno-inflammatory and O&NS pathways. Therefore, it may be concluded that immuno-inflammatory and O&NS pathways may play a role in the mitochondrial dysfunctions and consequently the bioenergetic abnormalities seen in patients with ME/cfs. Defects in ATP production and the electron transport complex, in turn, are associated with an elevated production of superoxide and hydrogen peroxide in mitochondria creating adaptive and synergistic damage. It is argued that mitochondrial dysfunctions, e.g. lowered ATP production, may play a role in the onset of ME/cfs symptoms, e.g. fatigue and post exertional malaise, and may explain in part the central metabolic abnormalities observed in ME/cfs, e.g. glucose hypometabolism and cerebral hypoperfusion.
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Bates MGD, Newman JH, Jakovljevic DG, Hollingsworth KG, Alston CL, Zalewski P, Klawe JJ, Blamire AM, MacGowan GA, Keavney BD, Bourke JP, Schaefer A, McFarland R, Newton JL, Turnbull DM, Taylor RW, Trenell MI, Gorman GS. Defining cardiac adaptations and safety of endurance training in patients with m.3243A>G-related mitochondrial disease. Int J Cardiol 2013; 168:3599-608. [PMID: 23742928 PMCID: PMC3819621 DOI: 10.1016/j.ijcard.2013.05.062] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2013] [Accepted: 05/04/2013] [Indexed: 01/14/2023]
Abstract
Background Cardiac hypertrophic remodelling and systolic dysfunction are common in patients with mitochondrial disease and independent predictors of morbidity and early mortality. Endurance exercise training improves symptoms and skeletal muscle function, yet cardiac adaptations are unknown. Methods and results Before and after 16-weeks of training, exercise capacity, cardiac magnetic resonance imaging and phosphorus-31 spectroscopy, disease burden, fatigue, quality of life, heart rate variability (HRV) and blood pressure variability (BPV) were assessed in 10 adult patients with m.3243A>G-related mitochondrial disease, and compared to age- and gender-matched sedentary control subjects. At baseline, patients had increased left ventricular mass index (LVMI, p < 0.05) and LV mass to end-diastolic volume ratio, and decreased longitudinal shortening and myocardial phosphocreatine/adenosine triphosphate ratio (all p < 0.01). Peak arterial–venous oxygen difference (p < 0.05), oxygen uptake (VO2) and power were decreased in patients (both p < 0.01) with no significant difference in cardiac power output. All patients remained stable and completed ≥ 80% sessions. With training, there were similar proportional increases in peak VO2, anaerobic threshold and work capacity in patients and controls. LVMI increased in both groups (p < 0.01), with no significant effect on myocardial function or bioenergetics. Pre- and post-exercise training, HRV and BPV demonstrated increased low frequency and decreased high frequency components in patients compared to controls (all p < 0.05). Conclusion Patients with mitochondrial disease and controls achieved similar proportional benefits of exercise training, without evidence of disease progression, or deleterious effects on cardiac function. Reduced exercise capacity is largely mediated through skeletal muscle dysfunction at baseline and sympathetic over-activation may be important in pathogenesis.
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Affiliation(s)
- Matthew G D Bates
- Wellcome Trust Centre for Mitochondrial Research, Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne NE2 4HH, UK; Cardiothoracic Centre, Freeman Hospital, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne NE7 7DN, UK.
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9
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Jeppesen TD, Vissing J, González-Alonso J. Influence of erythrocyte oxygenation and intravascular ATP on resting and exercising skeletal muscle blood flow in humans with mitochondrial myopathy. Mitochondrion 2011; 12:414-22. [PMID: 22155147 DOI: 10.1016/j.mito.2011.11.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Revised: 11/08/2011] [Accepted: 11/11/2011] [Indexed: 10/14/2022]
Abstract
Oxygen (O₂) extraction is impaired in exercising skeletal muscle of humans with mutations of mitochondrial DNA (mtDNA), but the muscle hemodynamic response to exercise has never been directly investigated. This study sought to examine the extent to which human skeletal muscle perfusion can increase without reductions in blood oxygenation and to determine whether erythrocyte O₂ off-loading and related ATP vascular mechanisms are impaired in humans with mutations of mtDNA. Leg vascular hemodynamic, oxygenation and ATP were investigated in ten patients with mtDNA mutations and ten matched healthy control subjects: 1) at rest during normoxia, hypoxia, hyperoxia and intra-femoral artery ATP infusion, and 2) during passive and dynamic one-legged knee-extensor exercises. At rest, blood flow (LBF), femoral arterial and venous blood oxygenation and plasma ATP were similar in the two groups. During dynamic exercise, LBF and vascular conductance increased 9-10 fold in the patients despite erythrocyte oxygenation and leg O₂ extraction remained unchanged (p<0.01). In the patients, workload-adjusted LBF was 28% to 62% higher during submaximal- and maximal exercises and was associated with augmented plasma ATP. The appropriate hemodynamic adjustments during severe hypoxia and ATP infusion suggest that erythrocyte O₂ off-loading and related ATP vascular mechanisms are intact in patients with mtDNA mutations. Furthermore, greater increase in plasma ATP and LBF at a given metabolic demand in the patients, in concert with unchanged oxyhemoglobin, suggest that erythrocyte O₂ off-loading is not obligatory for the exercise-induced increase in blood flow and intravascular ATP concentration.
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Affiliation(s)
- Tina D Jeppesen
- Department of Neurology, the Neuromuscular Research Unit, Denmark.
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Heinicke K, Taivassalo T, Wyrick P, Wood H, Babb TG, Haller RG. Exertional dyspnea in mitochondrial myopathy: clinical features and physiological mechanisms. Am J Physiol Regul Integr Comp Physiol 2011; 301:R873-84. [PMID: 21813873 DOI: 10.1152/ajpregu.00001.2011] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Exertional dyspnea limits exercise in some mitochondrial myopathy (MM) patients, but the clinical features of this syndrome are poorly defined, and its underlying mechanism is unknown. We evaluated ventilation and arterial blood gases during cycle exercise and recovery in five MM patients with exertional dyspnea and genetically defined mitochondrial defects, and in four control subjects (C). Patient ventilation was normal at rest. During exercise, MM patients had low Vo(2peak) (28 ± 9% of predicted) and exaggerated systemic O(2) delivery relative to O(2) utilization (i.e., a hyperkinetic circulation). High perceived breathing effort in patients was associated with exaggerated ventilation relative to metabolic rate with high VE/VO(2peak), (MM = 104 ± 18; C = 42 ± 8, P ≤ 0.001), and Ve/VCO(2peak)(,) (MM = 54 ± 9; C = 34 ± 7, P ≤ 0.01); a steeper slope of increase in ΔVE/ΔVCO(2) (MM = 50.0 ± 6.9; C = 32.2 ± 6.6, P ≤ 0.01); and elevated peak respiratory exchange ratio (RER), (MM = 1.95 ± 0.31, C = 1.25 ± 0.03, P ≤ 0.01). Arterial lactate was higher in MM patients, and evidence for ventilatory compensation to metabolic acidosis included lower Pa(CO(2)) and standard bicarbonate. However, during 5 min of recovery, despite a further fall in arterial pH and lactate elevation, ventilation in MM rapidly normalized. These data indicate that exertional dyspnea in MM is attributable to mitochondrial defects that severely impair muscle oxidative phosphorylation and result in a hyperkinetic circulation in exercise. Exaggerated exercise ventilation is indicated by markedly elevated VE/VO(2), VE/VCO(2), and RER. While lactic acidosis likely contributes to exercise hyperventilation, the fact that ventilation normalizes during recovery from exercise despite increasing metabolic acidosis strongly indicates that additional, exercise-specific mechanisms are responsible for this distinctive pattern of exercise ventilation.
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Affiliation(s)
- Katja Heinicke
- Neuromuscular Center, Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Ave., #435, Dallas, TX 75231-5129, USA.
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11
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Volpi L, Ricci G, Orsucci D, Alessi R, Bertolucci F, Piazza S, Simoncini C, Mancuso M, Siciliano G. Metabolic myopathies: functional evaluation by different exercise testing approaches. Musculoskelet Surg 2011; 95:59-67. [PMID: 21373907 DOI: 10.1007/s12306-011-0096-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Accepted: 02/09/2011] [Indexed: 11/26/2022]
Abstract
Metabolic myopathies are a clinically and etiologically heterogeneous group of disorders due to defects in muscular energy metabolism. They include glycogen storage diseases, fatty acid oxidation defects, and mitochondrial disorders. The typical manifestations of a metabolic myopathy are exercise-induced myalgias, exercise intolerance, and cramps. Evaluating subjects with such symptoms is not easy because of the frequent lack of clinical features. Exercise tests are, therefore, reliable screening tools. Here, we discuss the possible role of such exercise testing techniques in the diagnostic approach of a patient with suspected metabolic myopathy.
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Affiliation(s)
- L Volpi
- Department of Neuroscience, Neurological Clinic, University of Pisa, Via Roma 67, 56126 Pisa, Italy
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12
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SCHUMACHER YORCKOLAF, MUSER KLAUS, HIRSCHBERGER BARBARA, ROECKER KAI, DICKHUTH HANSHERRMANN, POTTGIESSER TORBEN. Hodgkin's Lymphoma in an Elite Endurance Athlete. Med Sci Sports Exerc 2008; 40:401-4. [DOI: 10.1249/mss.0b013e31815d8e8a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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13
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Tarnopolsky MA. What can metabolic myopathies teach us about exercise physiology? Appl Physiol Nutr Metab 2006; 31:21-30. [PMID: 16604138 DOI: 10.1139/h05-008] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Exercise physiologists are interested in metabolic myopathies because they demonstrate how knocking out a component of a specific biochemical pathway can alter cellular metabolism. McArdle's disease (myophosphorylase deficiency) has often been studied in exercise physiology to demonstrate the influence of removing the major anaerobic energy supply to skeletal muscle. Studies of patients with McArdle's disease have shown the increased reliance on blood-borne fuels, the importance of glycogen to maximal aerobic capacity, and the use of nutritional strategies to bypass metabolic defects. Myoadenylate deaminase deficiency is the most common metabolic enzyme deficiency in human skeletal muscle. It is usually compensated for endogenously and does not have a major influence on high-energy power output. Nutritional interventions such as carbohydrate loading and carbohydrate supplementation during exercise are essential components of therapy for patients with fatty acid oxidation defects. Cases of mitochondrial myopathies illustrate the importance of peripheral oxygen extraction for maximal aerobic capacity and show how both exercise and nutritional interventions can partially compensate for these mutations. In summary, metabolic myopathies provide important insights into regulatory and nutritional aspects of the major biochemical pathways of intermediary metabolism in human skeletal muscle. Key words: myoadenylate deaminase deficiency, MELAS syndrome, McArdle's disease, mitochondrial disease, inborn errors of metabolism.
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Affiliation(s)
- Mark A Tarnopolsky
- Department of Pediatrics and Medicine, Division of Neurology, McMaster University Medical Centre, Hamilton, ON, Canada.
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14
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Abstract
As it is under debate if determination of lactate during cycle ergometry (lactate stress testing, LST) under a continuous, unadjusted, low workload is a valuable diagnostic tool for mitochondrial myopathy (MMP), the present study aimed to investigate how sensitive the LST is in a large cohort of patients with indications for MMP (MMP patients). Serum lactate was determined once before, three times during, and once after a 15-min, constant 30 W-workload on a bicycle ergometer in 115 healthy controls, 166 patients with neurological disorders other than MMP, and 291 MMP patients. Serum lactate's upper reference limit at rest, 5, 10, 15 min after starting, and 15 min after finishing the exercise was 2.0, 2.0, 2.1, 2.0 and 1.7 mmol/l, respectively. Resting lactate was increased in 75 MMP patients (26%). The specificity of resting lactate determination was 84%. The sensitivity of the LST was 66% and the specificity 84%. Among the 192 MMP patients with abnormal LST, 120 (63%) had a normal resting lactate. The LST is abnormal in two thirds of the MMP patients. The sensitivity of the LST is higher than that of resting lactate determination. The LST is a simple and cheap but effective and reliable screening method for detecting the impaired oxidative metabolism in MMP.
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Affiliation(s)
- J Finsterer
- Neurological Hospital Rosenhügel, Vienna, Austria.
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15
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Abstract
Under normal healthy conditions, exercise initiates simultaneous elevations in hepatic glucose production (glucose R(a)) and glucose utilisation. As a result, circulating glucose levels are maintained at a relatively constant level. This relatively simple and effective relationship between the liver and the skeletal muscle is maintained by a complex interplay of circulating and locally released neuroendocrine controllers. In large part, exercise-induced changes in the pancreatic secretion of glucagon and insulin are primarily responsible for the stimulation of glucose R(a) during moderate exercise. However, exercise imposed on an additional metabolic stress (heavy exercise and poorly controlled diabetes mellitus) can increase sympathetic drive and has been suggested for decades to play a significant role in glucoregulation. In addition, blood-borne feedback and afferent reflex mechanisms may further modulate the glucose R(a) response to exercise. This article discusses new findings from novel animal and human experiments specifically designed to examine the regulatory components of the neuroendocrine system and their influence on glucoregulation during exercise.
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Affiliation(s)
- Robert H Coker
- Nutrition, Metabolism, and Exercise Laboratory, Department of Geriatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA.
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16
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Duncan GE, Perkins LA, Theriaque DW, Neiberger RE, Stacpoole PW. Dichloroacetate therapy attenuates the blood lactate response to submaximal exercise in patients with defects in mitochondrial energy metabolism. J Clin Endocrinol Metab 2004; 89:1733-8. [PMID: 15070938 DOI: 10.1210/jc.2003-031684] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We determined acute and chronic effects of dichloroacetate (DCA) on maximal (MAX) and submaximal (SUB) exercise responses in patients with abnormal mitochondrial energetics. Subjects (n = 9) completed a MAX treadmill bout 1 h after ingesting 25 mg/kg DCA or placebo (PL). A 15-min SUB bout was completed the next day while receiving the same treatment. After a 1-d washout, MAX and SUB were repeated while receiving the alternate treatment (acute). Gas exchange and heart rate were measured throughout all tests. Blood lactate (Bla) was measured 0, 3, and 10 min after MAX, and 5, 10, and 15 min during SUB. MAX and SUB were repeated after 3 months of daily DCA or PL. After a 2-wk washout, a final MAX and SUB were completed after 3 months of alternate treatment (chronic). Average Bla during SUB was lower (P < 0.05) during both acute (1.99 +/- 1.10 vs. 2.49 +/- 1.52 mmol/liter) and chronic (1.71 +/- 1.37 vs. 2.39 +/- 1.32 mmol/liter) DCA vs. PL despite similar exercise intensities between conditions ( approximately 75 and 70% maximal exercise capacity during acute and chronic treatment). Thus, although DCA does not alter MAX responses, acute and chronic DCA attenuate the Bla response to moderate exercise in patients with abnormal mitochondrial energetics.
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Affiliation(s)
- G E Duncan
- Department of Epidemiology, Nutritional Sciences Program, University of Washington, Seattle, Washington 98195, USA.
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17
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Hansen JE, Casaburi R. Mitochondrial disorders and exertional intolerance: controversy continues. Am J Respir Crit Care Med 2002; 166:118; author reply 119-20. [PMID: 12091181 DOI: 10.1164/ajrccm.166.1.16611] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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18
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Abstract
OBJECTIVE Few data are available about the diagnostic yield of the lactate stress test (LST) in a large group of patients with mitochondriopathy (MCP). METHODS Serum lactate was determined once before, three times during, and once after a 15-minute, constant 30W workload on a bicycle in 62 controls, aged 17 to 84 years, 155 patients with MCP, aged 17 to 87 years, and 31 patients with neurological disorders other than MCP. RESULTS Lactate's upper reference limits at rest, 5, 10, 15 minutes after starting, and 15 minutes after finishing the exercise were 2.0, 2.1, 2.1, 2.1 and 1.8 mmol/l respectively. The test was regarded abnormal if more than two of the five lactate values exceeded the cut-off levels. Among the 103 patients with abnormal LST, 64 (62 %) had normal resting lactate. The sensitivity of the test was 67% and the specificity 94%. CONCLUSION The LST proved to have a high sensitivity and specificity in the detection of patients with MCP, being thus a simple but powerful tool to assess the impaired oxidative metabolism in MCP patients.
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Affiliation(s)
- Josef Finsterer
- Ludwig Boltzmann Institute for Research in Neuromuscular Disorders, Vienna, Austria
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19
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Flaherty KR, Wald J, Weisman IM, Zeballos RJ, Schork MA, Blaivas M, Rubenfire M, Martinez FJ. Unexplained exertional limitation: characterization of patients with a mitochondrial myopathy. Am J Respir Crit Care Med 2001; 164:425-32. [PMID: 11500344 DOI: 10.1164/ajrccm.164.3.2005110] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Exercise intolerance is a common complaint, the cause of which often remains elusive after a comprehensive evaluation. In this report, we describe 28 patients with unexplained dyspnea or exertional limitation secondary to biopsy-proven mitochondrial myopathies. Patients were prospectively identified from a multidisciplinary dyspnea clinic at a tertiary referral center. All patients were without underlying pulmonary, cardiac, or other neuromuscular disorders. Patients underwent history, physical examination, complete pulmonary function testing, respiratory muscle testing, cardiopulmonary exercise testing, and muscle biopsy. Results were compared with a group of normal control subjects. The estimated period prevalence was 8.5% (28 of 331). Spirometry, lung volumes, and gas exchange were normal in patients and control subjects. Compared with control subjects, the patient group demonstrated decreased exercise capacity (maximum achieved V O(2) 67 versus 104% predicted; p < 0.0001) and respiratory muscle weakness (PI(max) 77 versus 115% predicted; p = 0.001). These patients have a characteristic exercise response that was hyperventilatory (peak VE/V CO(2); 55 versus 42) and hypercirculatory (maximum heart rate - baseline heart rate/V O(2)max - baseline V O(2)max; 91 versus 41) compared to control subjects. Patients stopping exercise due to dyspnea (n = 16) (as compared with muscle fatigue, n = 11) displayed weaker respiratory muscles (Pdi(max) 61 versus 115 cm H(2)O; p = 0.01) and were more likely to reach mechanical ventilatory limitation (V Emax/ MVV 0.81 versus 0.58; p = 0.02). The sensation of dyspnea was related to indices of respiratory muscle function including respiratory rate and inspiratory flow. We conclude that mitochondrial myopathies are more prevalent than previously reported. The characteristic physiological profile may be useful in the diagnostic evaluation of mitochondrial myopathy.
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Affiliation(s)
- K R Flaherty
- Dyspnea and Pulmonary Hypertension Clinics, University of Michigan Health System, Ann Arbor, Michigan, USA
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20
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Finsterer J, Milvay E. Diagnostic yield of the lactate stress test in respiratory chain disorders under absolute and relative workload. J Neurosci Methods 2001; 108:65-70. [PMID: 11459619 DOI: 10.1016/s0165-0270(01)00371-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Usually, the lactate stress test is carried under a constant, low workload maintained for 15 min, although there are indications that the lactate response to exercise is a function of the relative workload, and that a workload for only 5 min does not decrease its sensitivity. Thus, this study compared the diagnostic yield of the lactate stress test when carried out under a constant workload of 30 W (LSTA) and under a workload of 30% of maximum (LSTR), and when the workload was maintained for 5 and 15 min. In 16 patients with respiratory chain disorders, 12 women, four men, aged 27--88 years, the LSTA and LSTR were carried out on 2 different days, within 48 h. For both tests serum lactate was determined before, during and after a 15-min workload on a bicycle. Upper reference limits at rest, 5, 10, 15 min after starting, and 15 min after finishing the exercise were 1.9, 2.0, 2.0, 2.0, and 1.6 mmol/l for the LSTA, and 2.3, 3.0, 3.2, 3.4 and 2.7 mmol/l for the LSTR. The sensitivity was 88% for the LSTA and 63% for the LSTR. The specificity of the LSTA was 94%. The diagnostic yield of both tests was similar when the workload was maintained for 5 or 15 min. In conclusion, the LSTA should be preferred to the LSTR. Three lactate determinations during 15 min have no advantage over a single lactate determination after a 5 min workload of 30 W.
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Affiliation(s)
- J Finsterer
- Ludwig Boltzmann Institute for Research in Neuromuscular Disorders, Postfach 348, 1180 Vienna, Austria.
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21
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Vissing J, Gansted U, Quistorff B. Exercise intolerance in mitochondrial myopathy is not related to lactic acidosis. Ann Neurol 2001. [DOI: 10.1002/ana.1026] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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22
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Finsterer J, Obermann I, Milvay E. Diagnostic yield of the lactate stress test in 160 patients with suspected respiratory chain disorder. Metab Brain Dis 2000; 15:163-71. [PMID: 11206585 DOI: 10.1007/bf02674525] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Aim of the present study was to investigate the diagnostic yield of the lactate-stress-test in unselected patients with suspected respiratory-chain disorder (RCD). Serum lactate was determined before, during and after a 15-minute, constant 30W workload on a bicycle in 48 controls and 160 patients with suspected RCD. 122 had definite RCD, 38 neurological disorders other than RCD. The sensitivity, specificity, positive predictive value, negative predictive value and pre-test likelihood of the test was 69, 74, 89, 42 and 76% respectively. In conclusion, the lactate-stress-test proved a powerful tool to assess impaired oxidative metabolism in RCDs.
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Affiliation(s)
- J Finsterer
- Ludwig Boltzmann Institute for Research in Neuromuscular Disorders, Vienna, Austria
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23
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Abstract
Exercise intolerance is a common presenting symptom. The physiology of exercise intolerance in illustrative neurologic diseases is reviewed. Roles for exercise testing are identified, particularly in the evaluation of metabolic myopathies. The potential benefits of low intensity aerobic exercise training are described.
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Affiliation(s)
- T Taivassalo
- Research Assistant, Institute of Exercise and Environmental Medicine, Dallas, Texas
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24
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Siciliano G, Manca ML, Renna M, Prontera C, Mercuri A, Murri L. Effects of aerobic training on lactate and catecholaminergic exercise responses in mitochondrial myopathies. Neuromuscul Disord 2000; 10:40-5. [PMID: 10677862 DOI: 10.1016/s0960-8966(99)00068-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The aim of this study was to evaluate the effects of an aerobic training program on the metabolic and sympathetic responses to exercise in 12 patients with mitochondrial myopathies. A 10-week course of aerobic training, consisting of supervised exercise every other day on an electrically braked pedal-rate bicycle ergometer was prescribed to each patient and four healthy controls. Venous lactate, epinephrine (EP) and norepinephrine (NEP) levels were assessed at baseline and after the aerobic training by means of constant-workload exercise performed at near lactate threshold (LT). In patients, a decrease in exercise peak values, significant for lactate (-38.6%, P < 0.01) but not for catecholamines (EP: -26.0%, NEP: -22.1%) was observed after training, findings confirmed by the lactate/EP and lactate/NEP area ratios. The results show that lactate accumulation during exercise is decreased after aerobic training in mitochondrial myopathies and that the effect is partially dissociated from the catecholaminergic response. This in turn suggests that the lactate decrease can be explained, at least in part, by the improved muscle oxidative metabolism consequent to the proposed training program.
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Affiliation(s)
- G Siciliano
- Department of Neurosciences, University of Pisa, Italy.
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25
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Siciliano G, Renna M, Manca ML, Prontera C, Zucchelli G, Ferrannini E, Murri L. The relationship of plasma catecholamine and lactate during anaerobic threshold exercise in mitochondrial myopathies. Neuromuscul Disord 1999; 9:411-6. [PMID: 10545046 DOI: 10.1016/s0960-8966(99)00047-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Sympathetic system activation is considered one of the main factors influencing lactate production during exercise in normal individuals. In order to assess the role of such activation in mitochondrial myopathies, we compared blood catecholamine levels to those of lactate during an intermittent exercise performed at workloads near anaerobic lactate threshold. Following an initial increment, the patients (n = 10) exhibited a steady-state blood lactate shifted right relative to controls (n = 7), the peaks being respectively 665 +/- 29% and 322 +/- 11% of baseline. Plasma catecholamine increase in mitochondrial myopathies was 272 +/- 21% for norepinephrine and 261 +/- 18% for epinephrine, not statistically different from controls. Lactate/norepinephrine and lactate/epinephrine area ratios were significantly higher in the subjects than in controls (2.36 versus 1.48 and 2.40 versus 1.57, respectively). The study shows that the abnormal lactate production in mitochondrial myopathies is independent of the catecholaminergic response at the transition from aerobic to anaerobic exercise.
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Affiliation(s)
- G Siciliano
- Department of Neurosciences, Neurological Clinics, University of Pisa, Italy.
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26
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Finsterer J, Shorny S, Capek J, Cerny-Zacharias C, Pelzl B, Messner R, Bittner RE, Mamoli B. Lactate stress test in the diagnosis of mitochondrial myopathy. J Neurol Sci 1998; 159:176-80. [PMID: 9741404 DOI: 10.1016/s0022-510x(98)00170-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The aim of the study was to determine the sensitivity and specificity of the lactate stress test in the detection of mitochondrial myopathies. Thirty one healthy subjects, 10 patients with non-mitochondrial myopathy and 26 patients with mitochondrial myopathy underwent lactate stress testing at a standardized workload of 30 W during 15 min on a bicycle ergometer. Lactate was determined before the exercise (R1), 5, 10, 15 min after starting the exercise (S5, S10, S15) and 15 min after finishing the exercise (R2). A result was interpreted as pathologic if more than two of the five lactate values were above the corresponding upper reference limits. The upper reference limits for the venous lactate at R1, S5, S10, S15 and R2 were 1.9, 2.0, 2.1, 2.0 and 1.7 mmol/l respectively. The lactate stress test was pathologic in 1/10 of the non-mitochondrial myopathies and in 18/26 of the mitochondrial myopathies. The sensitivity of the lactate stress test was 69%. The specificity of the test was 90%. In conclusion, the lactate stress test proved to be helpful for evaluating the integrity of the oxidative metabolism in the majority of patients with mitochondrial myopathy.
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Affiliation(s)
- J Finsterer
- Ludwig Boltzmann Institute for Research in Neuromuscular Disorders, Vienna, Austria
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27
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Stallknecht B, Vissing J, Galbo H. Lactate production and clearance in exercise. Effects of training. A mini-review. Scand J Med Sci Sports 1998; 8:127-31. [PMID: 9659671 DOI: 10.1111/j.1600-0838.1998.tb00181.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Lactate accumulates if pyruvate formation exceeds pyruvate oxidation. Accelerated glycogenolysis is essential for lactate production. Glycogen and epinephrine enhance glycogen phosphorylase activity and this is higher in type II b than in type I fibers. Pyruvate oxidation is enhanced by exercise-induced increase in pyruvate dehydrogenase activity and is relatively impaired by low oxygen availability and low mitochondrial oxidative capacity. During exercise lactate is eliminated in liver, heart, and resting and working muscle. In muscle, elimination depends on plasma concentration, fiber type, and fiber conditions. Due to influence on hormonal response, mitochondrial oxidative capacity and fiber recruitment, training diminishes glycogenolysis and lactate production. Training also increases lactate clearance. This reflects increased hepatic capacity for gluconeogenesis as well as increased lactate transport capacity and oxidative capacity and reduced glycogenolysis in muscle. The fact that endurance performance can be predicted from the plasma lactate versus exercise intensity relationship illustrates that the plasma lactate level is a finely balanced result of the interplay between many factors of importance for endurance exercise.
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Affiliation(s)
- B Stallknecht
- Department of Medical Physiology, University of Copenhagen, Denmark
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28
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Vissing J, Vissing SF, MacLean DA, Saltin B, Quistorff B, Haller RG. Sympathetic activation in exercise is not dependent on muscle acidosis. Direct evidence from studies in metabolic myopathies. J Clin Invest 1998; 101:1654-60. [PMID: 9541495 PMCID: PMC508746 DOI: 10.1172/jci555] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Muscle acidosis has been implicated as a major determinant of reflex sympathetic activation during exercise. To test this hypothesis we studied sympathetic exercise responses in metabolic myopathies in which muscle acidosis is impaired or augmented during exercise. As an index of reflex sympathetic activation to muscle, microneurographic measurements of muscle sympathetic nerve activity (MSNA) were obtained from the peroneal nerve. MSNA was measured during static handgrip exercise at 30% of maximal voluntary contraction force to exhaustion in patients in whom exercise-induced muscle acidosis is absent (seven myophosphorylase deficient patients; MD [McArdle's disease], and one patient with muscle phosphofructokinase deficiency [PFKD]), augmented (one patient with mitochondrial myopathy [MM]), or normal (five healthy controls). Muscle pH was monitored by 31P-magnetic resonance spectroscopy during handgrip exercise in the five control subjects, four MD patients, and the MM and PFKD patients. With handgrip to exhaustion, the increase in MSNA over baseline (bursts per minute [bpm] and total activity [%]) was not impaired in patients with MD (17+/-2 bpm, 124+/-42%) or PFKD (65 bpm, 307%), and was not enhanced in the MM patient (24 bpm, 131%) compared with controls (17+/-4 bpm, 115+/-17%). Post-handgrip ischemia studied in one McArdle patient, caused sustained elevation of MSNA above basal suggesting a chemoreflex activation of MSNA. Handgrip exercise elicited an enhanced drop in muscle pH of 0.51 U in the MM patient compared with the decrease in controls of 0.13+/-0.02 U. In contrast, muscle pH increased with exercise in MD by 0.12+/-0.05 U and in PFKD by 0.01 U. In conclusion, patients with glycogenolytic, glycolytic, and oxidative phosphorylation defects show normal muscle sympathetic nerve responses to static exercise. These findings indicate that muscle acidosis is not a prerequisite for sympathetic activation in exercise.
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Affiliation(s)
- J Vissing
- The Copenhagen Muscle Research Center, National University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark
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29
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Kjær M. Hepatic Glucose Production during Exercise. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1998. [DOI: 10.1007/978-1-4899-1928-1_11] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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