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Habets LE, Bartels B, Asselman FL, Hooijmans MT, van den Berg S, Nederveen AJ, van der Pol WL, Jeneson JAL. Magnetic resonance reveals mitochondrial dysfunction and muscle remodelling in spinal muscular atrophy. Brain 2021; 145:1422-1435. [PMID: 34788410 PMCID: PMC9128825 DOI: 10.1093/brain/awab411] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 09/24/2021] [Accepted: 10/08/2021] [Indexed: 11/14/2022] Open
Abstract
Genetic therapy has changed the prognosis of hereditary proximal spinal muscular atrophy, although treatment efficacy has been variable. There is a clear need for deeper understanding of underlying causes of muscle weakness and exercise intolerance in patients with this disease to further optimize treatment strategies. Animal models suggest that in addition to motor neuron and associated musculature degeneration, intrinsic abnormalities of muscle itself including mitochondrial dysfunction contribute to the disease aetiology. To test this hypothesis in patients, we conducted the first in vivo clinical investigation of muscle bioenergetics. We recruited 15 patients and 15 healthy age and gender-matched control subjects in this cross-sectional clinico-radiological study. MRI and 31P magnetic resonance spectroscopy, the modality of choice to interrogate muscle energetics and phenotypic fibre-type makeup, was performed of the proximal arm musculature in combination with fatiguing arm-cycling exercise and blood lactate testing. We derived bioenergetic parameter estimates including: blood lactate, intramuscular pH and inorganic phosphate accumulation during exercise, and muscle dynamic recovery constants. A linear correlation was used to test for associations between muscle morphological and bioenergetic parameters and clinico-functional measures of muscle weakness. MRI showed significant atrophy of triceps but not biceps muscles in patients. Maximal voluntary contraction force normalized to muscle cross-sectional area for both arm muscles was 1.4-fold lower in patients than in controls, indicating altered intrinsic muscle properties other than atrophy contributed to muscle weakness in this cohort. In vivo31P magnetic resonance spectroscopy identified white-to-red remodelling of residual proximal arm musculature in patients on the basis of altered intramuscular inorganic phosphate accumulation during arm-cycling in red versus white and intermediate myofibres. Blood lactate rise during arm-cycling was blunted in patients and correlated with muscle weakness and phenotypic muscle makeup. Post-exercise metabolic recovery was slower in residual intramuscular white myofibres in patients demonstrating mitochondrial ATP synthetic dysfunction in this particular fibre type. This study provides the first in vivo evidence in patients that degeneration of motor neurons and associated musculature causing atrophy and muscle weakness in 5q spinal muscular atrophy type 3 and 4 is aggravated by disproportionate depletion of myofibres that contract fastest and strongest. Our finding of decreased mitochondrial ATP synthetic function selectively in residual white myofibres provides both a possible clue to understanding the apparent vulnerability of this particular fibre type in 5q spinal muscular atrophy types 3 and 4 as well as a new biomarker and target for therapy.
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Affiliation(s)
- Laura E Habets
- Centre for Child Development, Exercise and Physical Literacy, Wilhelmina Children's Hospital, University Medical Centre Utrecht, P.O. Box 85090 3508 AB Utrecht, The Netherlands
| | - Bart Bartels
- Centre for Child Development, Exercise and Physical Literacy, Wilhelmina Children's Hospital, University Medical Centre Utrecht, P.O. Box 85090 3508 AB Utrecht, The Netherlands
| | - Fay-Lynn Asselman
- UMC Utrecht Brain Centre, Department of Neurology and Neurosurgery, University Medical Centre Utrecht Brain Center, Utrecht University, P.O. Box 85500, 3508 GA Utrecht, The Netherlands
| | - Melissa T Hooijmans
- Department of Radiology & Nuclear Medicine, Amsterdam Movement Sciences, Amsterdam University Medical Centre, location AMC, 1105 AZ Amsterdam, The Netherlands
| | - Sandra van den Berg
- Department of Radiology & Nuclear Medicine, Amsterdam Movement Sciences, Amsterdam University Medical Centre, location AMC, 1105 AZ Amsterdam, The Netherlands
| | - Aart J Nederveen
- Department of Radiology & Nuclear Medicine, Amsterdam Movement Sciences, Amsterdam University Medical Centre, location AMC, 1105 AZ Amsterdam, The Netherlands
| | - W Ludo van der Pol
- UMC Utrecht Brain Centre, Department of Neurology and Neurosurgery, University Medical Centre Utrecht Brain Center, Utrecht University, P.O. Box 85500, 3508 GA Utrecht, The Netherlands
| | - Jeroen A L Jeneson
- Centre for Child Development, Exercise and Physical Literacy, Wilhelmina Children's Hospital, University Medical Centre Utrecht, P.O. Box 85090 3508 AB Utrecht, The Netherlands
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Heskamp L, Lebbink F, van Uden MJ, Maas MC, Claassen JAHR, Froeling M, Kemp GJ, Boss A, Heerschap A. Post-exercise intramuscular O 2 supply is tightly coupled with a higher proximal-to-distal ATP synthesis rate in human tibialis anterior. J Physiol 2021; 599:1533-1550. [PMID: 33369737 PMCID: PMC7986184 DOI: 10.1113/jp280771] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 12/21/2020] [Indexed: 11/08/2022] Open
Abstract
Key points The post‐exercise recovery of phosphocreatine, a measure of the oxidative capacity of muscles, as assessed by 31P MR spectroscopy, shows a striking increase from distal to proximal along the human tibialis anterior muscle. To investigate why this muscle exhibits a greater oxidative capacity proximally, we tested whether the spatial variation in phosphocreatine recovery rate is related to oxygen supply, muscle fibre type or type of exercise. We revealed that oxygen supply also increases from distal to proximal along the tibialis anterior, and that it strongly correlated with phosphocreatine recovery. Carnosine level, a surrogate measure for muscle fibre type was not different between proximal and distal, and type of exercise did not affect the gradient in phosphocreatine recovery rate. Taken together, the findings of this study suggest that the post‐exercise spatial gradients in oxygen supply and phosphocreatine recovery are driven by a higher intrinsic mitochondrial oxidative capacity proximally.
Abstract Phosphorus magnetic resonance spectroscopy (31P MRS) of human tibialis anterior (TA) revealed a strong proximo‐distal gradient in the post‐exercise phosphocreatine (PCr) recovery rate constant (kPCr), a measure of muscle oxidative capacity. The aim of this study was to investigate whether this kPCr gradient is related to O2 supply, resting phosphorylation potential, muscle fibre type, or type of exercise. Fifteen male volunteers performed continuous isometric ankle dorsiflexion at 30% maximum force until exhaustion. At multiple locations along the TA, we measured the oxidative PCr resynthesis rate (VPCr = kPCr × PCr depletion) by 31P MRS, the oxyhaemoglobin recovery rate constant (kO2Hb) by near infrared spectroscopy, and muscle perfusion with MR intravoxel incoherent motion imaging. The kO2Hb, kPCr, VPCr and muscle perfusion depended on measurement location (P < 0.001, P < 0.001, P = 0.032 and P = 0.003, respectively), all being greater proximally. The kO2Hb and muscle perfusion correlated with kPCr (r = 0.956 and r = 0.852, respectively) and VPCr (r = 0.932 and r = 0.985, respectively), the latter reflecting metabolic O2 consumption. Resting phosphorylation potential (PCr/inorganic phosphate) was also higher proximally (P < 0.001). The surrogate for fibre type, carnosine content measured by 1H MRS, did not differ between distal and proximal TA (P = 0.884). Performing intermittent exercise to avoid exercise ischaemia, still led to larger kPCr proximally than distally (P = 0.013). In conclusion, the spatial kPCr gradient is strongly associated with the spatial variation in O2 supply. It cannot be explained by exercise‐induced ischaemia nor by fibre type. Our findings suggest it is driven by a higher proximal intrinsic mitochondrial oxidative capacity, apparently to support contractile performance of the TA. The post‐exercise recovery of phosphocreatine, a measure of the oxidative capacity of muscles, as assessed by 31P MR spectroscopy, shows a striking increase from distal to proximal along the human tibialis anterior muscle. To investigate why this muscle exhibits a greater oxidative capacity proximally, we tested whether the spatial variation in phosphocreatine recovery rate is related to oxygen supply, muscle fibre type or type of exercise. We revealed that oxygen supply also increases from distal to proximal along the tibialis anterior, and that it strongly correlated with phosphocreatine recovery. Carnosine level, a surrogate measure for muscle fibre type was not different between proximal and distal, and type of exercise did not affect the gradient in phosphocreatine recovery rate. Taken together, the findings of this study suggest that the post‐exercise spatial gradients in oxygen supply and phosphocreatine recovery are driven by a higher intrinsic mitochondrial oxidative capacity proximally.
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Affiliation(s)
- Linda Heskamp
- Department of Medical Imaging/Radiology, Radboud university medical center, Nijmegen, The Netherlands
| | - Franciska Lebbink
- Department of Medical Imaging/Radiology, Radboud university medical center, Nijmegen, The Netherlands
| | - Mark J van Uden
- Department of Medical Imaging/Radiology, Radboud university medical center, Nijmegen, The Netherlands
| | - Marnix C Maas
- Department of Medical Imaging/Radiology, Radboud university medical center, Nijmegen, The Netherlands
| | - Jurgen A H R Claassen
- Department of Geriatrics, Radboud university medical center, Nijmegen, The Netherlands
| | - Martijn Froeling
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Graham J Kemp
- Department of Musculoskeletal and Ageing Science, University of Liverpool, Liverpool, UK
| | - Andreas Boss
- Department of Medical Imaging/Radiology, Radboud university medical center, Nijmegen, The Netherlands
| | - Arend Heerschap
- Department of Medical Imaging/Radiology, Radboud university medical center, Nijmegen, The Netherlands
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Wilcox M, Wright SM, McDougall M. A Review of Non-1H RF Receive Arrays in Magnetic Resonance Imaging and Spectroscopy. IEEE OPEN JOURNAL OF ENGINEERING IN MEDICINE AND BIOLOGY 2020; 1:290-300. [PMID: 35402958 PMCID: PMC8975242 DOI: 10.1109/ojemb.2020.3030531] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 09/15/2020] [Accepted: 09/25/2020] [Indexed: 11/16/2022] Open
Abstract
It is now common practice to use radiofrequency (RF) coils to increase the signal-to-noise ratio (SNR) in 1H magnetic resonance imaging and spectroscopy experiments. Use of array coils for non-1H experiments, however, has been historically more limited despite the fact that these nuclei suffer inherently lower sensitivity and could benefit greatly from an increased SNR. Recent advancements in receiver technology and increased support from scanner manufacturers have now opened greater options for the use of array coils for non-1H magnetic resonance experiments. This paper reviews the research in adopting array coil technology with an emphasis on studies of the most commonly studied non-1H nuclei including 31P, 13C, 23Na, and 19F. These nuclei offer complementary information to 1H imaging and spectroscopy and have proven themselves important in the study of numerous disease processes. While recent work with non-1H array coils has shown promising results, the technology is not yet widely utilized and should see substantial developments in the coming years.
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Bendahan D, Chatel B, Jue T. Comparative NMR and NIRS analysis of oxygen-dependent metabolism in exercising finger flexor muscles. Am J Physiol Regul Integr Comp Physiol 2017; 313:R740-R753. [PMID: 28877871 DOI: 10.1152/ajpregu.00203.2017] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 08/07/2017] [Accepted: 08/30/2017] [Indexed: 02/08/2023]
Abstract
Muscle contraction requires the physiology to adapt rapidly to meet the surge in energy demand. To investigate the shift in metabolic control, especially between oxygen and metabolism, researchers often depend on near-infrared spectroscopy (NIRS) to measure noninvasively the tissue O2 Because NIRS detects the overlapping myoglobin (Mb) and hemoglobin (Hb) signals in muscle, interpreting the data as an index of cellular or vascular O2 requires deconvoluting the relative contribution. Currently, many in the NIRS field ascribe the signal to Hb. In contrast, 1H NMR has only detected the Mb signal in contracting muscle, and comparative NIRS and NMR experiments indicate a predominant Mb contribution. The present study has examined the question of the NIRS signal origin by measuring simultaneously the 1H NMR, 31P NMR, and NIRS signals in finger flexor muscles during the transition from rest to contraction, recovery, ischemia, and reperfusion. The experiment results confirm a predominant Mb contribution to the NIRS signal from muscle. Given the NMR and NIRS corroborated changes in the intracellular O2, the analysis shows that at the onset of muscle contraction, O2 declines immediately and reaches new steady states as contraction intensity rises. Moreover, lactate formation increases even under quite aerobic condition.
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Affiliation(s)
- David Bendahan
- Aix-Marseille Univ, Centre National de la Recherche Scientifique, Centre de Résonance Magnétique Biologique et Médicale, Marseille, France
| | - Benjamin Chatel
- Aix-Marseille Univ, Centre National de la Recherche Scientifique, Centre de Résonance Magnétique Biologique et Médicale, Marseille, France
| | - Thomas Jue
- Biochemistry and Molecular Medicine, University of California Davis, Davis, California; and
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Wilcox MD, Del Bosque R, Parizek K, Sia J, Eigenbrodt ED, McDougall MP. A three-element 1H-31P dual-tuned array for magnetic resonance spectroscopy at 4.7 T. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2016; 2016:6258-6261. [PMID: 28269681 DOI: 10.1109/embc.2016.7592159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This work describes the construction and testing of a three-element, double-tuned receive array and transmit coils for 31P-1H spectroscopy and imaging. The receive coils were geometrically-decoupled, single-loop surface coils and the transmit coils were concentric saddle coils. The coils were used to examine a physiologically-modeled CNC-milled phantom. The receive coil array was able to improve SNR while also providing gross localization of the 1H and 31P signals.
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Sagui E, Montigon C, Abriat A, Jouvion A, Duron-Martinaud S, Canini F, Zagnoli F, Bendahan D, Figarella-Branger D, Brégigeon M, Brosset C. Is there a link between exertional heat stroke and susceptibility to malignant hyperthermia? PLoS One 2015; 10:e0135496. [PMID: 26258863 PMCID: PMC4530942 DOI: 10.1371/journal.pone.0135496] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2014] [Accepted: 07/22/2015] [Indexed: 11/18/2022] Open
Abstract
Objective The identification of a predisposition toward malignant hyperthermia (MH) as a risk factor for exertional heat stroke (EHS) remains a matter of debate. Such a predisposition indicates a causal role for MH susceptibility (MHS) after EHS in certain national recommendations and has led to the use of an in vitro contracture test (IVCT) to identify the MHS trait in selected or unselected EHS patients. The aim of this study was to determine whether the MHS trait is associated with EHS. Methods EHS subjects in the French Armed Forces were routinely examined for MHS after experiencing an EHS episode. This retrospective study compared the features of IVCT-diagnosed MHS (iMHS) EHS subjects with those of MH-normal EHS patients and MH patients during the 2004–2010 period. MHS status was assessed using the European protocol. Results During the study period, 466 subjects (median age 25 years; 31 women) underwent MHS status investigation following an EHS episode. None of the subjects reported previous MH events. An IVCT was performed in 454 cases and was diagnostic of MHS in 45.6% of the study population, of MH susceptibility to halothane in 18.5%, of MH susceptibility to caffeine in 9.9%, and of MH susceptibility to halothane and caffeine in 17.2%. There were no differences in the clinical features, biological features or outcomes of iMHS EHS subjects compared with those of MH-normal or caffeine or halothane MHS subjects without known prior EHS episode. The recurrence rate was 12.7% and was not associated with MH status or any clinical or biological features. iMHS EHS patients exhibited a significantly less informative IVCT response than MH patients. Conclusions The unexpected high prevalence of the MHS trait after EHS suggested a latent disturbance of calcium homeostasis that accounted for the positive IVCT results. This study did not determine whether EHS patients have an increased risk of MH, and it could not determine whether MH susceptibility is a risk factor for EHS.
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Affiliation(s)
- Emmanuel Sagui
- French Military Hospital Laveran, Marseille, France
- Val de Grâce Military School, Paris, France
- Unité mixte de recherche 7291, laboratoire de neurosciences cognitives, Aix Marseille University, Marseille, France
- * E-mail:
| | - Coline Montigon
- French Military Hospital Laveran, Marseille, France
- Val de Grâce Military School, Paris, France
| | | | | | | | - Frédéric Canini
- Val de Grâce Military School, Paris, France
- Armed Forces Biomedical Research Institute, Brétigny/Orge, France
| | - Fabien Zagnoli
- Val de Grâce Military School, Paris, France
- French Military Hospital Clermont-Tonnerre, Brest, France
| | - David Bendahan
- Unité mixte de recherché 7339, Center for Magnetic Resonance in Biology and Medicine, Aix Marseille University, Marseille, France
| | - Dominique Figarella-Branger
- Service d’anatomie pathologique et de neuropathologie, Timone hospital, assistance publique/hôpitaux de Marseille, Marseille, France
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Kemp GJ, Ahmad RE, Nicolay K, Prompers JJ. Quantification of skeletal muscle mitochondrial function by 31P magnetic resonance spectroscopy techniques: a quantitative review. Acta Physiol (Oxf) 2015; 213:107-44. [PMID: 24773619 DOI: 10.1111/apha.12307] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2013] [Revised: 12/30/2013] [Accepted: 04/23/2014] [Indexed: 12/16/2022]
Abstract
Magnetic resonance spectroscopy (MRS) can give information about cellular metabolism in vivo which is difficult to obtain in other ways. In skeletal muscle, non-invasive (31) P MRS measurements of the post-exercise recovery kinetics of pH, [PCr], [Pi] and [ADP] contain valuable information about muscle mitochondrial function and cellular pH homeostasis in vivo, but quantitative interpretation depends on understanding the underlying physiology. Here, by giving examples of the analysis of (31) P MRS recovery data, by some simple computational simulation, and by extensively comparing data from published studies using both (31) P MRS and invasive direct measurements of muscle O2 consumption in a common analytical framework, we consider what can be learnt quantitatively about mitochondrial metabolism in skeletal muscle using MRS-based methodology. We explore some technical and conceptual limitations of current methods, and point out some aspects of the physiology which are still incompletely understood.
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Affiliation(s)
- G. J. Kemp
- Department of Musculoskeletal Biology, and Magnetic Resonance and Image Analysis Research Centre; University of Liverpool; Liverpool UK
| | - R. E. Ahmad
- Department of Musculoskeletal Biology, and Magnetic Resonance and Image Analysis Research Centre; University of Liverpool; Liverpool UK
| | - K. Nicolay
- Biomedical NMR; Department of Biomedical Engineering; Eindhoven University of Technology; Eindhoven the Netherlands
| | - J. J. Prompers
- Biomedical NMR; Department of Biomedical Engineering; Eindhoven University of Technology; Eindhoven the Netherlands
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Kappenstein J, Ferrauti A, Runkel B, Fernandez-Fernandez J, Müller K, Zange J. Reply to: The rate of PCr resynthesis is not a reliable index of skeletal muscle oxidative capacity. Eur J Appl Physiol 2013; 114:219-220. [PMID: 24233243 DOI: 10.1007/s00421-013-2766-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Accepted: 10/25/2013] [Indexed: 10/26/2022]
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Layec G, Malucelli E, Le Fur Y, Manners D, Yashiro K, Testa C, Cozzone PJ, Iotti S, Bendahan D. Effects of exercise-induced intracellular acidosis on the phosphocreatine recovery kinetics: a 31P MRS study in three muscle groups in humans. NMR IN BIOMEDICINE 2013; 26:1403-1411. [PMID: 23703831 DOI: 10.1002/nbm.2966] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Revised: 03/22/2013] [Accepted: 03/25/2013] [Indexed: 06/02/2023]
Abstract
Little is known about the metabolic differences that exist among different muscle groups within the same subjects. Therefore, we used (31)P-magnetic resonance spectroscopy ((31)P-MRS) to investigate muscle oxidative capacity and the potential effects of pH on PCr recovery kinetics between muscles of different phenotypes (quadriceps (Q), finger (FF) and plantar flexors (PF)) in the same cohort of 16 untrained adults. The estimated muscle oxidative capacity was lower in Q (29 ± 12 mM min(-1), CV(inter-subject) = 42%) as compared with PF (46 ± 20 mM min(-1), CV(inter-subject) = 44%) and tended to be higher in FF (43 ± 35 mM min(-1), CV(inter-subject) = 80%). The coefficient of variation (CV) of oxidative capacity between muscles within the group was 59 ± 24%. PCr recovery time constant was correlated with end-exercise pH in Q (p < 0.01), FF (p < 0.05) and PF (p < 0.05) as well as proton efflux rate in FF (p < 0.01), PF (p < 0.01) and Q (p = 0.12). We also observed a steeper slope of the relationship between end-exercise acidosis and PCr recovery kinetics in FF compared with either PF or Q muscles. Overall, this study supports the concept of skeletal muscle heterogeneity by revealing a comparable inter- and intra-individual variability in oxidative capacity across three skeletal muscles in untrained individuals. These findings also indicate that the sensitivity of mitochondrial respiration to the inhibition associated with cytosolic acidosis is greater in the finger flexor muscles compared with locomotor muscles, which might be related to differences in permeability in the mitochondrial membrane and, to some extent, to proton efflux rates.
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Affiliation(s)
- Gwenael Layec
- Centre de Resonance Magnetique Biologique et Medicale, UMR CNRS 6612, Faculté de Médecine de Marseille, Marseille, France; Department of Medicine, Division of Geriatrics, University of Utah, Salt Lake City, UT, USA; Geriatric Research, Education, and Clinical Center, George E. Whalen VA Medical Center, Salt Lake City, UT, USA
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Kappenstein J, Ferrauti A, Runkel B, Fernandez-Fernandez J, Müller K, Zange J. Changes in phosphocreatine concentration of skeletal muscle during high-intensity intermittent exercise in children and adults. Eur J Appl Physiol 2013; 113:2769-79. [PMID: 23995672 DOI: 10.1007/s00421-013-2712-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 08/14/2013] [Indexed: 11/28/2022]
Abstract
PURPOSE The aim of the present study was to test the hypotheses that a greater oxidative capacity in children results in a lower phosphocreatine (PCr) depletion, a faster PCr resynthesis and a lower muscle acidification during high-intensity intermittent exercise compared to adults. METHODS Sixteen children (9.4 ± 0.5 years) and 16 adults (26.1 ± 0.3 years) completed a protocol consisting of a dynamic plantar flexion (10 bouts of 30-s exercise at 25 % of one repetition maximum separated by 20-s recovery), followed by 10 min of passive recovery. Changes of PCr, ATP, inorganic phosphate, and phosphomonoesters were measured by means of (31)Phosphorous-magnetic resonance spectroscopy during and post-exercise. RESULTS Average PCr (percentage of [PCr] at initial rest (%[PCr]i)) at the end of the exercise (adults 17 ± 12 %[PCr]i, children 38 ± 17 %[PCr]i, P < 0.01) and recovery periods (adults 37 ± 14 %[PCr]i, children 57 ± 17 %[PCr]i, P < 0.01) was significantly lower in adults compared to children, induced by a stronger PCr decrease during the first exercise interval (adults -73 ± 10 %[PCr]i, children -55 ± 15 %[PCr]i, P < 0.01). End-exercise pH was significantly higher in children compared to adults (children 6.90 + 0.20, -0.14; adults 6.67 + 0.23, -0.15, P < 0.05). CONCLUSIONS From our results we suggest relatively higher rates of oxidative ATP formation in children's muscle for covering the ATP demand of high-intensity intermittent exercise compared to adults, enabling children to begin each exercise interval with significantly higher PCr concentrations and leading to an overall lower muscle acidification.
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Affiliation(s)
- J Kappenstein
- Department of Training and Exercise Science, Faculty of Sport Science, Ruhr-University Bochum, Gesundheitscampus Nord Haus Nr. 10, 44780, Bochum, Germany,
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11
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Exertional muscle pain in familial Mediterranean fever patients evaluated by MRI and 31P magnetic resonance spectroscopy. Clin Radiol 2013; 68:371-5. [DOI: 10.1016/j.crad.2012.08.030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2012] [Revised: 08/28/2012] [Accepted: 08/31/2012] [Indexed: 11/23/2022]
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12
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Malucelli E, Iotti S, Manners D, Testa C, Martinuzzi A, Barbiroli B, Lodi R. The role of pH on the thermodynamics and kinetics of muscle biochemistry: An in vivo study by 31P-MRS in patients with myo-phosphorylase deficiency. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2011; 1807:1244-9. [DOI: 10.1016/j.bbabio.2011.06.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Revised: 04/14/2011] [Accepted: 06/16/2011] [Indexed: 10/18/2022]
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Layec G, Bringard A, Le Fur Y, Vilmen C, Micallef JP, Perrey S, Cozzone PJ, Bendahan D. Comparative determination of energy production rates and mitochondrial function using different 31P MRS quantitative methods in sedentary and trained subjects. NMR IN BIOMEDICINE 2011; 24:425-438. [PMID: 20963767 DOI: 10.1002/nbm.1607] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Revised: 06/02/2010] [Accepted: 07/23/2010] [Indexed: 05/30/2023]
Abstract
Muscle energetics has been largely and quantitatively investigated using (31)P MRS. Various methods have been used to estimate the corresponding rate of oxidative ATP synthesis (ATP(ox)); however, potential differences among methods have not been investigated. In this study, we aimed to compare the rates of ATP production and energy cost in two groups of subjects with different training status using four different methods: indirect method (method 1), ADP control model (method 2) and phosphate potential control model (method 3). Method 4 was a modified version of method 3 with the introduction of a correction factor allowing for similar values to be obtained for the end-exercise oxidative ATP synthesis rate inferred from exercise measurements and the initial recovery phosphocreatine resynthesis rate. Seven sedentary and seven endurance-trained subjects performed a dynamic standardised rest-exercise-recovery protocol. We quantified the rates of ATP(ox) and anaerobic ATP synthesis (ATP(ana)) using (31)P MRS data recorded at 1.5 T. The rates of ATP(ox) over the entire exercise session were independent of the method used, except for method 4 which provided significantly higher values in both groups (p < 0.01). In addition, methods 1-3 were cross-correlated, thereby confirming their statistical agreement. The rate of ATP(ana) was significantly higher with method 1 (p < 0.01) and lower with method 4 (p < 0.01). As a result of the higher rate of ATP(ox), EC (method 4) calculated over the entire exercise session was higher and initial EC (method 1) was lower in both groups compared with the other methods. We showed in this study that the rate of ATP(ox) was independent of the calculation method, as long as no corrections (method 4) were performed. In contrast, results related to the rates of ATP(ana) were strongly affected by the calculation method and, more exactly, by the estimation of protons generated by ATP(ox). Although the absolute EC values differed between the methods, within- or between-subject comparisons are still valid given the tight relationships between them.
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Affiliation(s)
- Gwenael Layec
- Centre de Resonance Magnetique Biologique et Medicale, Faculté de Médecine de Marseille, France
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Meyerspeer M, Scheenen T, Schmid AI, Mandl T, Unger E, Moser E. Semi-LASER localized dynamic 31P magnetic resonance spectroscopy in exercising muscle at ultra-high magnetic field. Magn Reson Med 2011; 65:1207-15. [PMID: 21384422 PMCID: PMC3272370 DOI: 10.1002/mrm.22730] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Revised: 09/18/2010] [Accepted: 10/25/2010] [Indexed: 11/10/2022]
Abstract
Magnetic resonance spectroscopy (MRS) can benefit from increased signal-to-noise ratio (SNR) of high magnetic fields. In this work, the SNR gain of dynamic 31P MRS at 7 T was invested in temporal and spatial resolution. Using conventional slice selective excitation combined with localization by adiabatic selective refocusing (semi-LASER) with short echo time (TE = 23 ms), phosphocreatine quantification in a 38 mL voxel inside a single exercising muscle becomes possible from single acquisitions, with SNR = 42 ± 4 in resting human medial gastrocnemius. The method was used to quantify the phosphocreatine time course during 5 min of plantar flexion exercise and recovery with a temporal resolution of 6 s (the chosen repetition time for moderate T1 saturation). Quantification of inorganic phosphate and pH required accumulation of consecutively acquired spectra when (resting) Pi concentrations were low. The localization performance was excellent while keeping the chemical shift displacement acceptably small. The SNR and spectral line widths with and without localization were compared between 3 T and 7 T systems in phantoms and in vivo. The results demonstrate that increased sensitivity of ultra-high field can be used to dynamically acquire metabolic information from a clearly defined region in a single exercising muscle while reaching a temporal resolution previously available with MRS in non-localizing studies only. The method may improve the interpretation of dynamic muscle MRS data. Magn Reson Med, 2011. © 2011 Wiley-Liss, Inc.
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Affiliation(s)
- Martin Meyerspeer
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Wien, Austria
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15
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Tonson A, Ratel S, Le Fur Y, Vilmen C, Cozzone PJ, Bendahan D. Muscle energetics changes throughout maturation: a quantitative 31P-MRS analysis. J Appl Physiol (1985) 2010; 109:1769-78. [PMID: 20847131 DOI: 10.1152/japplphysiol.01423.2009] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We quantified energy production in 7 prepubescent boys (11.7 ± 0.6 yr) and 10 men (35.6 ± 7.8 yr) using (31)P-magnetic resonance spectroscopy to investigate whether development affects muscle energetics, given that resistance to fatigue has been reported to be larger before puberty. Each subject performed a finger flexions exercise at 0.7 Hz against a weight adjusted to 15% of their maximal voluntary strength for 3 min, followed by a 15-min recovery period. The total energy cost was similar in both groups throughout the exercise bout, whereas the interplay of the different metabolic pathways was different. At the onset of exercise, children exhibited a higher oxidative contribution (50 ± 15% in boys and 25 ± 8% in men, P < 0.05) to ATP production, whereas the phosphocreatine breakdown contribution was reduced (40 ± 10% in boys and 53 ± 12% in men, P < 0.05), likely as a compensatory mechanism. The anaerobic glycolysis activity was unaffected by maturation. The recovery phase also disclosed differences regarding the rates of proton efflux (6.2 ± 2.5 vs. 3.8 ± 1.9 mM · pH unit(-1) · min(-1), in boys and men, respectively, P < 0.05), and phosphocreatine recovery, which was significantly faster in boys than in men (rate constant of phosphocreatine recovery: 1.3 ± 0.5 vs. 0.7 ± 0.4 min(-1); V(max): 37.5 ± 14.5 vs. 21.1 ± 12.2 mM/min, in boys and men, respectively, P < 0.05). Our results obtained in vivo clearly showed that maturation affects muscle energetics. Children relied more on oxidative metabolism and less on creatine kinase reaction to meet energy demand during exercise. This phenomenon can be explained by a greater oxidative capacity, probably linked to a higher relative content in slow-twitch fibers before puberty.
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Affiliation(s)
- Anne Tonson
- Centre de Résonance Magnétique Biologique et Médicale, UMR Centre National de la Recherche Scientifique 6612, Faculté de Médecine de Marseille, Université de la Méditerranée, Marseille, France
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16
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Iotti S, Borsari M, Bendahan D. Oscillations in energy metabolism. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:1353-61. [DOI: 10.1016/j.bbabio.2010.02.019] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Revised: 02/17/2010] [Accepted: 02/17/2010] [Indexed: 11/26/2022]
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Ratel S, Tonson A, Cozzone PJ, Bendahan D. Do oxidative and anaerobic energy production in exercising muscle change throughout growth and maturation? J Appl Physiol (1985) 2010; 109:1562-4. [PMID: 20466806 DOI: 10.1152/japplphysiol.00167.2010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Sébastien Ratel
- Clermont Université, Université Blaise Pascal, Laboratoire de Biologie des Activités Physiques et Sportives, Clermont-Ferrand, France.
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18
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Layec G, Bringard A, Le Fur Y, Vilmen C, Micallef JP, Perrey S, Cozzone PJ, Bendahan D. Reproducibility assessment of metabolic variables characterizing muscle energetics in vivo: A 31P-MRS study. Magn Reson Med 2010; 62:840-54. [PMID: 19725136 DOI: 10.1002/mrm.22085] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The purpose of the present study was to assess the reliability of metabolic parameters measured using (31)P magnetic resonance spectroscopy ((31)P MRS) during two standardized rest-exercise-recovery protocols. Twelve healthy subjects performed the standardized protocols at two different intensities; i.e., a moderate intensity (MOD) repeated over a two-month period and heavy intensity (HEAVY) repeated over a year's time. Test-retest reliability was analyzed using coefficient of variation (CV), limits of agreement (LOA), and intraclass correlation coefficients (ICC). During exercise and recovery periods, most of the metabolic parameters exhibited a good reliability. The CVs of individual concentration of phosphocreatine ([PCr]), concentration of adenosine diphosphate ([ADP]), and pH values recorded at end of the HEAVY exercise were lower than 15%. The CV calculated for the rate of PCr resynthesis and the maximal oxidative capacity were less than 13% during the HEAVY protocol. Inferred parameters such as oxidative and total adenosine triphosphate (ATP) production rates exhibited a good reliability (ICC approximately 0.7; CV < 15% during the HEAVY protocol). Our results demonstrated that measurement error using (31)P-MRS during a standardized exercise was low and that biological variability accounted for the vast majority of the measurement variability. In addition, the corresponding metabolic measurements can reliably be used for longitudinal studies performed even over a long period of time.
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Affiliation(s)
- Gwenael Layec
- Centre de Resonance Magnetique Biologique et Medicale, UMR CNRS 6612, Faculté de Médecine de Marseille, Marseille, France
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Fleischman A, Kron M, Systrom DM, Hrovat M, Grinspoon SK. Mitochondrial function and insulin resistance in overweight and normal-weight children. J Clin Endocrinol Metab 2009; 94:4923-30. [PMID: 19846731 PMCID: PMC2795647 DOI: 10.1210/jc.2009-1590] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
BACKGROUND Obesity has become an epidemic in children, associated with an increase in insulin resistance and metabolic dysfunction. Mitochondrial function is known to be an important determinant of glucose metabolism in adults. However, little is known about the relationship between mitochondrial function and obesity, insulin resistance, energy expenditure, and pubertal development in children. METHODS Seventy-four participants, 37 overweight (> or = 85th percentile body mass index for age and sex) and 37 normal-weight (< 85th percentile) without personal or family history of diabetes mellitus were enrolled. Subjects were evaluated with an oral glucose tolerance test, metabolic markers, resting energy expenditure, Tanner staging, and (31)P magnetic resonance spectroscopy of skeletal muscle for mitochondrial function. RESULTS Overweight and normal-weight children showed no difference in muscle ATP synthesis [phosphocreatine (PCr) recovery after exercise] (32.4 +/- 2.3 vs. 34.1 +/- 2.1, P = 0.58). However, insulin-resistant children had significantly prolonged PCr recovery when compared with insulin-sensitive children, by homeostasis model assessment for insulin resistance quartile (ANOVA, P = 0.04). Similarly, insulin-resistant overweight children had PCr recovery that was prolonged compared with insulin-sensitive overweight children (P = 0.01). PCr recovery was negatively correlated with resting energy expenditure in multivariate modeling (P = 0.03). Mitochondrial function worsened during mid-puberty in association with insulin resistance. CONCLUSION Reduced skeletal muscle mitochondrial oxidative phosphorylation, assessed by PCr recovery, is associated with insulin resistance and an altered metabolic phenotype in children. Normal mitochondrial function may be associated with a healthier metabolic phenotype in overweight children. Further studies are needed to investigate the long-term physiological consequences and potential treatment strategies targeting children with reduced mitochondrial function.
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Affiliation(s)
- Amy Fleischman
- Program in Nutritional Metabolism, Massachusetts General Hospital, 55 Fruit Street, LON 207, Boston, Massachusetts 02114, USA.
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20
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Ratel S, Tonson A, Le Fur Y, Cozzone P, Bendahan D. Comparative analysis of skeletal muscle oxidative capacity in children and adults: a 31P-MRS study. Appl Physiol Nutr Metab 2008; 33:720-7. [PMID: 18641715 DOI: 10.1139/h08-039] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The aim of the present study was to compare the oxidative capacity of the forearm flexor muscles in vivo between children and adults using 31-phosphorus magnetic resonance spectroscopy. Seven boys (11.7 +/- 0.6 y) and 10 men (35.6 +/- 7.8 year) volunteered to perform a 3 min dynamic finger flexions exercise against a standardized weight (15% of the maximal voluntary contraction). Muscle oxidative capacity was quantified on the basis of phosphocreatine (PCr) post-exercise recovery kinetics analysis. End-of-exercise pH was not significantly different between children and adults (6.6 +/- 0.2 vs. 6.5 +/- 0.2), indicating that indices of PCr recovery kinetics can be reliably compared. The rate constant of PCr recovery (kPCr) and the maximum rate of aerobic ATP production were about 2-fold higher in young boys than in men (kPCr: 1.7 +/- 1.2 vs. 0.7 +/- 0.2 min(-1); Vmax: 49.7 +/- 24.6 vs. 29.4 +/- 7.9 mmol.L(-1).min(-1), p < 0.05). Our results clearly illustrate a greater mitochondrial oxidative capacity in the forearm flexor muscles of young children. This larger ATP regeneration capacity through aerobic mechanisms in children could be one of the factors accounting for their greater resistance to fatigue during high-intensity intermittent exercise.
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Affiliation(s)
- Sébastien Ratel
- Laboratory of Exercise Biology BAPS, EA 3533, Universite Blaise Pascal, UFR STAPS, 63172 Aubiere, France.
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21
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Kemp GJ, Meyerspeer M, Moser E. Absolute quantification of phosphorus metabolite concentrations in human muscle in vivo by 31P MRS: a quantitative review. NMR IN BIOMEDICINE 2007; 20:555-65. [PMID: 17628042 DOI: 10.1002/nbm.1192] [Citation(s) in RCA: 215] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
31P MRS offers a unique view of muscle metabolism in vivo, but correct quantification is important. Inter-study correlation of estimates of [Pi] and [phosphocreatine (PCr)] in a number of published studies suggest that the main technical problem in calibrated 31P MRS studies is the measurement of PCr and Pi signal intensities, rather than absolute quantification of [ATP]. For comparison, we discuss the few published biopsy studies of calf muscle and a selection of the many studies of quadriceps muscle. The ATP concentration is close to the value that we obtained in calf muscle in our own study, presented here, on four healthy subjects, by localised 31P MRS using a surface coil incorporating an internal reference and calibrated using an external phantom. However, the freeze-clamp biopsy PCr concentration is approximately 20% lower than the value obtained by 31P MRS, consistent with PCr breakdown by creatine kinase during freezing. Finally, we illustrate some consequences of uncertainty in resting [PCr] for analysis of mitochondrial function from PCr kinetics using a published 31P MRS study of exercise and recovery: the lower the assumed resting [PCr], the lower the absolute rate of oxidative ATP synthesis estimated from the PCr resynthesis rate; in addition, the lower the assumed resting [PCr], or the higher the assumed [total creatine], the higher the apparent resting [ADP], and therefore the more sigmoid the relationship between the rate of oxidative ATP synthesis and [ADP]. Correct quantification of resting metabolite concentrations is crucially important for this sort of analysis. Our own results ([PCr] = 33 +/- 2 mM, [Pi] = 4.5 +/- 0.2 mM, and [ATP] = 8.2 +/- 0.4 mM; mean +/- SEM) are close to the overall mean values of the 10 published studies on calf muscle by 'calibrated' 31P MRS (as in the present work), and of [PCr] and [Pi] in a representative selection of 'uncalibrated' 31P MRS studies (i.e. from measured PCr/ATP and Pi/ATP ratios, assuming a literature value for [ATP]).
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Affiliation(s)
- Graham J Kemp
- Division of Metabolic and Cellular Medicine, Faculty of Medicine, University of Liverpool, Liverpool, UK
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22
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Meyerspeer M, Kemp GJ, Mlynárik V, Krššák M, Szendroedi J, Nowotny P, Roden M, Moser E. Direct noninvasive quantification of lactate and high energy phosphates simultaneously in exercising human skeletal muscle by localized magnetic resonance spectroscopy. Magn Reson Med 2007; 57:654-60. [PMID: 17390348 PMCID: PMC4876926 DOI: 10.1002/mrm.21188] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A novel method based on interleaved localized 31P- and 1H MRS is presented, by which lactate accumulation and the accompanying changes in high energy phosphates in human skeletal muscle can be monitored simultaneously during exercise and recovery. Lactate is quantified using a localized double quantum filter suppressing the abundant lipid signals while taking into account orientation dependent signal modulations. Lactate concentration after ischemic exercise directly quantified by DQF 1H spectroscopy was 24 +/- 3 mmol/L cell water, while 22 +/- 3 mmol/L was expected on the basis of 31P MRS acquired simultaneously. Lactate concentration in a sample of porcine meat was estimated to be 40 +/- 7 mmol/L by means of DQF quantitation, versus 39 +/- 5 mmol/L by biochemical methods. Excellent agreement is shown between lactate concentrations measured noninvasively by 1H MRS, measured biochemically ex vivo, and inferred indirectly in vivo from changes in pH, P(i), and PCr as obtained from 31P MRS data.
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Affiliation(s)
- Martin Meyerspeer
- MR Centre of Excellence, Medical University of Vienna, Austria
- Center for Biomedical Engineering and Physics, Medical University of Vienna, Austria
| | - Graham J. Kemp
- Division of Metabolic and Cellular Medicine, School of Clinical Science, Faculty of Medicine, University of Liverpool, United Kingdom
| | - Vladimir Mlynárik
- MR Centre of Excellence, Medical University of Vienna, Austria
- Center for Biomedical Engineering and Physics, Medical University of Vienna, Austria
| | - Martin Krššák
- MR Centre of Excellence, Medical University of Vienna, Austria
- Department of Internal Medicine III, Division of Endocrinology and Metabolism, Medical University of Vienna, Austria
| | - Julia Szendroedi
- Department of Internal Medicine III, Division of Endocrinology and Metabolism, Medical University of Vienna, Austria
- Karl-Landsteiner Institute of Endocrinology and Metabolism, Vienna, Austria
| | - Peter Nowotny
- Department of Internal Medicine III, Division of Endocrinology and Metabolism, Medical University of Vienna, Austria
| | - Michael Roden
- Department of Internal Medicine III, Division of Endocrinology and Metabolism, Medical University of Vienna, Austria
- Karl-Landsteiner Institute of Endocrinology and Metabolism, Vienna, Austria
- 1st Med. Department, Hanusch Hospital Vienna, Austria
| | - Ewald Moser
- MR Centre of Excellence, Medical University of Vienna, Austria
- Center for Biomedical Engineering and Physics, Medical University of Vienna, Austria
- Department of Diagnostic Radiology, Medical University of Vienna, Austria
- Correspondence to: Ewald Moser, MR Centre of Excellence, Medical University of Vienna, Lazarettgasse 14, A-1090 Vienna, Austria.
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van den Broek NMA, De Feyter HMML, de Graaf L, Nicolay K, Prompers JJ. Intersubject differences in the effect of acidosis on phosphocreatine recovery kinetics in muscle after exercise are due to differences in proton efflux rates. Am J Physiol Cell Physiol 2007; 293:C228-37. [PMID: 17392383 DOI: 10.1152/ajpcell.00023.2007] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
(31)P magnetic resonance spectroscopy provides the possibility of obtaining bioenergetic data during skeletal muscle exercise and recovery. The time constant of phosphocreatine (PCr) recovery (tau(PCr)) has been used as a measure of mitochondrial function. However, cytosolic pH has a strong influence on the kinetics of PCr recovery, and it has been suggested that tau(PCr) should be normalized for end-exercise pH. A general correction can only be applied if there are no intersubject differences in the pH dependence of tau(PCr). We investigated the pH dependence of tau(PCr) on a subject-by-subject basis. Furthermore, we determined the kinetics of proton efflux at the start of recovery. Intracellular acidosis slowed PCr recovery, and the pH dependence of tau(PCr) differed among subjects, ranging from -33.0 to -75.3 s/pH unit. The slope of the relation between tau(PCr) and end-exercise pH was positively correlated with both the proton efflux rate and the apparent proton efflux rate constant, indicating that subjects with a smaller pH dependence of tau(PCr) have a higher proton efflux rate. Our study implies that simply correcting tau(PCr) for end-exercise pH is not adequate, in particular when comparing patients and control subjects, because certain disorders are characterized by altered proton efflux from muscle fibers.
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Affiliation(s)
- Nicole M A van den Broek
- Biomedical NMR, Dept. of Biomedical Engineering, Eindhoven University of Technology, N-laag b1.08, PO Box 513, 5600 MB Eindhoven, The Netherlands
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24
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Kemp G. Mitochondrial respiration in creatine-loaded muscle: is there 31P-MRS evidence of direct effects of phosphocreatine and creatine in vivo? J Appl Physiol (1985) 2007; 100:1428-9; author reply 1429-30. [PMID: 16540719 DOI: 10.1152/japplphysiol.01269.2005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Recent human isolated muscle fiber studies suggest that phosphocreatine (PCr) and creatine (Cr) concentrations play a role in the regulation of mitochondrial respiration rate. To determine whether similar regulatory mechanisms are present in vivo, this study examined the relationship between skeletal muscle mitochondrial respiration rate and end-exercise PCr, Cr, PCr-to-Cr ratio (PCr/Cr), ADP, and pH by using 31P-magnetic resonance spectroscopy in 16 men and women (36.9 ± 4.6 yr). The initial PCr resynthesis rate and time constant (Tc) were used as indicators of mitochondrial respiration after brief (10–12 s) and exhaustive (1–4 min) dynamic knee extension exercise performed in placebo and creatine-supplemented conditions. The results show that the initial PCr resynthesis rate has a strong relationship with end-exercise PCr, Cr, and PCr/Cr ( r > 0.80, P < 0.001), a moderate relationship with end-exercise ADP ( r = 0.77, P < 0.001), and no relationship with end-exercise pH ( r = −0.14, P = 0.34). The PCr Tc was not as strongly related to PCr, Cr, PCr/Cr, and ADP ( r < 0.77, P < 0.001–0.18) and was significantly influenced by end-exercise pH ( r = −0.43, P < 0.01). These findings suggest that end-exercise PCr and Cr should be taken into consideration when PCr recovery kinetics is used as an indicator of mitochondrial respiration and that the initial PCr resynthesis rate is a more reliable indicator of mitochondrial respiration compared with the PCr Tc.
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25
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Praet SFE, De Feyter HMM, Jonkers RAM, Nicolay K, van Pul C, Kuipers H, van Loon LJC, Prompers JJ. 31P MR spectroscopy and in vitro markers of oxidative capacity in type 2 diabetes patients. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2006; 19:321-31. [PMID: 17180611 DOI: 10.1007/s10334-006-0060-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2006] [Revised: 10/26/2006] [Accepted: 11/06/2006] [Indexed: 01/07/2023]
Abstract
BACKGROUND Skeletal muscle mitochondrial function in type 2 diabetes (T2D) is currently being studied intensively. In vivo (31)P magnetic resonance spectroscopy ((31)P MRS) is a noninvasive tool used to measure mitochondrial respiratory function (MIFU) in skeletal muscle tissue. However, microvascular co-morbidity in long-standing T2D can interfere with the (31)P MRS methodology. AIM To compare (31)P MRS-derived parameters describing in vivo MIFU with an in vitro assessment of muscle respiratory capacity and muscle fiber-type composition in T2D patients. METHODS (31)P MRS was applied in long-standing, insulin-treated T2D patients. (31)P MRS markers of MIFU were measured in the M. vastus lateralis. Muscle biopsy samples were collected from the same muscle and analyzed for succinate dehydrogenase activity (SDH) and fiber-type distribution. RESULTS Several (31)P MRS parameters of MIFU showed moderate to good correlations with the percentage of type I fibers and type I fiber-specific SDH activity (Pearson's R between 0.70 and 0.75). In vivo and in vitro parameters of local mitochondrial respiration also correlated well with whole-body fitness levels (VO (2peak)) in these patients (Pearson's R between 0.62 and 0.90). CONCLUSION Good correlations exist between in vivo and in vitro measurements of MIFU in long-standing insulin-treated T2D subjects, which are qualitatively and quantitatively consistent with previous results measured in healthy subjects. This justifies the use of (31)P MRS to measure MIFU in relation to T2D.
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Affiliation(s)
- S F E Praet
- Department of Movement Sciences, Nutrition and Toxicology Research Institute Maastricht, Maastricht University, 6200, MD, Maastricht, The Netherlands.
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26
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Raja MK, Raymer GH, Moran GR, Marsh G, Thompson RT. Changes in tissue water content measured with multiple-frequency bioimpedance and metabolism measured with 31P-MRS during progressive forearm exercise. J Appl Physiol (1985) 2006; 101:1070-5. [PMID: 16794019 DOI: 10.1152/japplphysiol.01322.2005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Multiple-frequency bioimpedance analysis (MFBIA) has been used to determine the cellular water composition in the human body. It is noninvasive and has demonstrated good correlations with other invasive measures of tissue water. However, the ability of this method to study transient changes in tissue water in specific muscle groups has not been explored. In this study, MFBIA was used to assess changes in forearm intracellular water (ICW), extracellular water (ECW), and total water (TW) in seven healthy volunteers during and after a progressive wrist flexion exercise protocol. In an identical trial, (31)P magnetic resonance spectroscopy ((31)P-MRS) was used to assess changes in intracellular pH and phosphocreatine (PCr). At the completion of exercise, forearm ICW increased 12.6% (SD 0.07, P = 0.003), TW increased 10.1% (SD 0.06, P = 0.005), and no significant changes were recorded for ECW. A significant correlation was found between the changes in intracellular pH and changes in ICW during exercise (r = -0.84, P = 0.018). With the use of regression analysis, average changes in P(i), PCr, and pH were found to predict changes in ICW (R(2) = 0.98, P = 0.005). In conclusion, MFBIA was sensitive enough to measure transient changes in the exercising forearm muscle. The changes seen were consistent with the hypothesis that intracellular acidification and PCr hydrolysis are important mediators of cellular osmolality and therefore may be responsible for the increased volume of water in the intracellular space that is often recorded after short-term high-intensity exercise.
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Affiliation(s)
- Mohan K Raja
- Department of Radiology, St. Joseph's Health Center, University of Western Ontario, 268 Grosvenor St., London, Ontario, Canada, N6A 4V2
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Bendahan D, Mattei JP, Guis S, Kozak-Ribbens G, Cozzone PJ. [Non-invasive investigation of muscle function using 31P magnetic resonance spectroscopy and 1H MR imaging]. Rev Neurol (Paris) 2006; 162:467-84. [PMID: 16585908 DOI: 10.1016/s0035-3787(06)75038-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
31P MRS and 1H MRI of skeletal muscle have become major new tools allowing a complete non invasive investigation of muscle function both in the clinical setting and in basic research. The comparative analysis of normal and diseased muscle remains a major requirement to further define metabolic events surrounding muscle contraction and the metabolic anomalies underlying pathologies. Also, standardized rest-exercise-recovery protocols for the exploration of muscle metabolism by P-31 MRS in healthy volunteers as well as in patients with intolerance to exercise have been developed. The CRMBM protocol is based on a short-term intense exercise, which is very informative and well accepted by volunteers and patients. Invariant metabolic parameters have been defined to characterize the normal metabolic response to the protocol. Deviations from normality can be directly interpreted in terms of specific pathologies in some favorable cases. This protocol has been applied to more than 4,000 patients and healthy volunteers over a period of 15 years. On the other hand, MRI investigations provide anatomical and functional information from resting and exercising muscle. From a diagnostic point of view, dedicated pulse sequences can be used in order to detect and quantify muscle inflammation, fatty replacement, muscle hyper and hypotrophy. In most cases, MR techniques provide valuable information which has to be processed in conjunction with traditional invasive biochemical, electrophysiological and histoenzymological tests. P-31 MRS has proved particularly useful in the therapeutic follow-up of palliative therapies (coenzyme Q treatment of mitochondriopathies) and in family investigations. It is now an accepted diagnostic tool in the array of tests which are used to characterize muscle disorders in clinical routine. As a research tool, it will keep bringing new information on the physiopathology of muscle diseases in animal models and in humans and should play a role in the metabolic characterization of gene and cell therapy.
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Affiliation(s)
- D Bendahan
- Centre de Résonance Magnétique Biologique et Médicale (CRMBM), UMR CNRS No 6612, Faculté de Médecine de Marseille.
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McKeough ZJ, Alison JA, Bye PTP, Trenell MI, Sachinwalla T, Thompson CH, Kemp GJ. Exercise capacity and quadriceps muscle metabolism following training in subjects with COPD. Respir Med 2006; 100:1817-25. [PMID: 16516454 DOI: 10.1016/j.rmed.2006.01.017] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2005] [Revised: 01/18/2006] [Accepted: 01/23/2006] [Indexed: 11/15/2022]
Abstract
The aim of the study was to determine whether 16 sessions of exercise training, completed twice weekly, alters exercise capacity, quadriceps muscle metabolism, cross-sectional area (CSA) and strength in subjects with chronic obstructive pulmonary disease (COPD). We studied (a) 10 COPD subjects (mean age+/-sem = 71+/-2 years; FEV1 = 0.99+/-0.1 L) before and after 16 sessions of exercise training, and (b) 10 healthy subjects (age = 68+/-3 years). The COPD subjects underwent an incremental peak exercise test using a cycle ergometer and a 6-min walk test: both improved following exercise training (P < 0.05). Magnetic resonance spectroscopy measurements, in quadriceps muscle, of post-exercise phosphocreatinine (PCr) recovery kinetics were used to assess mitochondrial function in vivo: in the COPD subjects pre-training this was 19+/-8% lower than in healthy subjects (P = 0.03), but a 38+/-12% increase was seen in the COPD subjects following training (P = 0.003). Magnetic resonance imaging was used to assess quadriceps CSA: after training in the COPD subjects this showed a 7+/-2% increase (P = 0.03). Quadriceps strength, measured by the best of five maximum voluntary contractions, also showed a 32+/-11% increase in the COPD subjects (P = 0.007). Sixteen sessions of exercise training, performed twice weekly, increased exercise capacity as well as quadriceps mitochondrial capacity, CSA and strength in the subjects with COPD.
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Affiliation(s)
- Zoe J McKeough
- Department of Respiratory Medicine, Level 11 West, Building 75, Royal Prince Alfred Hospital, Missenden Rd, Camperdown, NSW, Australia 2050.
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Trenell MI, Sue CM, Kemp GJ, Sachinwalla T, Thompson CH. Aerobic exercise and muscle metabolism in patients with mitochondrial myopathy. Muscle Nerve 2006; 33:524-31. [PMID: 16372322 DOI: 10.1002/mus.20484] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Exercise therapy improves mitochondrial function in patients with mitochondrial myopathy (MM). We undertook this study to determine the metabolic abnormalities that are improved by exercise therapy. This study identified metabolic pathology using (31)P-magnetic resonance spectroscopy and magnetic resonance imaging (MRI) in a group of patients with MM compared to a control group matched for age, gender, and physical activity. We also observed the effect of exercise therapy for 12 weeks on muscle metabolism and physical function in the MM group. During muscle activity, there was impaired responsiveness of the mitochondria to changes in cytosolic adenosine diphosphate concentration, increased dependence on anaerobic energy pathways, and an adaptive increase in proton efflux in patients with MM. Following exercise therapy, mitochondrial function and muscle mass improved without any change in proton efflux rate. These metabolic findings were accompanied by improvements in functional ability. We conclude that there are significant metabolic differences between patients with MM and a control population, independent of age, gender, and physical activity. Exercise therapy can assist in improving mitochondrial function in MM patients.
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Affiliation(s)
- Michael I Trenell
- School of Molecular and Microbial Bioscience, University of Sydney, Sydney, Australia
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30
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Iotti S, Gottardi G, Clementi V, Barbiroli B. The mono-exponential pattern of phosphocreatine recovery after muscle exercise is a particular case of a more complex behaviour. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2004; 1608:131-9. [PMID: 14871490 DOI: 10.1016/j.bbabio.2003.11.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2003] [Revised: 11/13/2003] [Accepted: 11/13/2003] [Indexed: 11/16/2022]
Abstract
A mathematical model is proposed showing that the mono-exponential recovery of phosphocreatine (PCr) after exercise is an approximation of a more complex pattern, which is identified by a second-order differential equation. The model predicts the possibility of three different patterns of PCr recovery: bi-exponential, oscillatory damped, and critically damped; the mono-exponential pattern being a particular case of the functions which are solutions of the differential equation. The model was tested on a sample of recovery data from 50 volunteers, checking whether the recovery patterns predicted by the model lead to a significant improvement of fit (IF) compared with the mono-exponential pattern. Results show that the IF is linked to pH. Bi-exponential solutions showed an IF in the pH range 6.65-6.85, and the oscillatory solutions at pH>6.9. Critically damped solutions displayed a poor IF. Oscillation frequencies found in the oscillatory recoveries increase at increasing pH. These results show that pH has a pivotal role on the pattern of PCr recovery and implications on the regulation of oxidative phosphorylation are discussed.
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Affiliation(s)
- S Iotti
- Dipartimento di Medicina Clinica e Biotecnologia Applicata "D Campanacci", Università di Bologna, via Massarenti, 9, 40138 Bologna, Italy.
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31
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Bendahan D, Kemp GJ, Roussel M, Fur YL, Cozzone PJ. ATP synthesis and proton handling in muscle during short periods of exercise and subsequent recovery. J Appl Physiol (1985) 2003; 94:2391-7. [PMID: 12611771 DOI: 10.1152/japplphysiol.00589.2002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We used (31)P-magnetic resonance spectroscopy to study proton buffering in finger flexor muscles of eight healthy men (25-45 yr), during brief (18-s) voluntary finger flexion exercise (0.67-Hz contraction at 10% maximum voluntary contraction; 50/50 duty cycle) and 180-s recovery. Phosphocreatine (PCr) concentration fell 19 +/- 2% during exercise and then recovered with half time = 0.24 +/- 0.01 min. Cell pH rose by 0.058 +/- 0.003 units during exercise as a result of H(+) consumption by PCr splitting, which (assuming no lactate production or H(+) efflux) implies a plausible non-P(i) buffer capacity of 20 +/- 3 mmol. l intracellular water(-1). pH unit(-1). There was thus no evidence of significant glycogenolysis to lactate during exercise. Analysis of PCr kinetics as a classic linear response suggests that oxidative ATP synthesis reached 48 +/- 2% of ATP demand by the end of exercise; the rest was met by PCr splitting. Postexercise pH recovery was faster than predicted, suggesting "excess proton" production, with a peak value of 0.6 +/- 0.2 mmol/l intracellular water at 0.45 min of recovery, which might be due to, e.g., proton influx driven by cellular alkalinization, or a small glycolytic contribution to PCr resynthesis in recovery.
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Affiliation(s)
- David Bendahan
- Faculté de Médecine, Centre de Resonance Magnetique Biologique et Medicale, Unité Mixte de Recherche 6612 Centre National de la Recherche Scientifique, Marseille 13005, France.
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32
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Abstract
Within the skeletal muscle cell at the onset of muscular contraction, phosphocreatine (PCr) represents the most immediate reserve for the rephosphorylation of adenosine triphosphate (ATP). As a result, its concentration can be reduced to less than 30% of resting levels during intense exercise. As a fall in the level of PCr appears to adversely affect muscle contraction, and therefore power output in a subsequent bout, maximising the rate of PCr resynthesis during a brief recovery period will be of benefit to an athlete involved in activities which demand intermittent exercise. Although this resynthesis process simply involves the rephosphorylation of creatine by aerobically produced ATP (with the release of protons), it has both a fast and slow component, each proceeding at a rate that is controlled by different components of the creatine kinase equilibrium. The initial fast phase appears to proceed at a rate independent of muscle pH. Instead, its rate appears to be controlled by adenosine diphosphate (ADP) levels; either directly through its free cytosolic concentration, or indirectly, through its effect on the free energy of ATP hydrolysis. Once this fast phase of recovery is complete, there is a secondary slower phase that appears almost certainly rate-dependent on the return of the muscle cell to homeostatic intracellular pH. Given the importance of oxidative phosphorylation in this resynthesis process, those individuals with an elevated aerobic power should be able to resynthesise PCr at a more rapid rate than their sedentary counterparts. However, results from studies that have used phosphorus nuclear magnetic resonance ((31)P-NMR) spectroscopy, have been somewhat inconsistent with respect to the relationship between aerobic power and PCr recovery following intense exercise. Because of the methodological constraints that appear to have limited a number of these studies, further research in this area is warranted.
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Affiliation(s)
- Shaun McMahon
- School of Human Movement Studies, University of Queensland, Brisbane, Queensland, Australia.
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33
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Bendahan D, Mattei JP, Ghattas B, Confort-Gouny S, Le Guern ME, Cozzone PJ. Citrulline/malate promotes aerobic energy production in human exercising muscle. Br J Sports Med 2002; 36:282-9. [PMID: 12145119 PMCID: PMC1724533 DOI: 10.1136/bjsm.36.4.282] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Previous studies have shown an antiasthenic effect of citrulline/malate (CM) but the mechanism of action at the muscular level remains unknown. OBJECTIVE To investigate the effects of CM supplementation on muscle energetics. METHODS Eighteen men complaining of fatigue but with no documented disease were included in the study. A rest-exercise (finger flexions)-recovery protocol was performed twice before (D-7 and D0), three times during (D3, D8, D15), and once after (D22) 15 days of oral supplementation with 6 g/day CM. Metabolism of the flexor digitorum superficialis was analysed by (31)P magnetic resonance spectroscopy at 4.7 T. RESULTS Metabolic variables measured twice before CM ingestion showed no differences, indicating good reproducibility of measurements and no learning effect from repeating the exercise protocol. CM ingestion resulted in a significant reduction in the sensation of fatigue, a 34% increase in the rate of oxidative ATP production during exercise, and a 20% increase in the rate of phosphocreatine recovery after exercise, indicating a larger contribution of oxidative ATP synthesis to energy production. Considering subjects individually and variables characterising aerobic function, extrema were measured after either eight or 15 days of treatment, indicating chronological heterogeneity of treatment induced changes. One way analysis of variance confirmed improved aerobic function, which may be the result of an enhanced malate supply activating ATP production from the tricarboxylic acid cycle through anaplerotic reactions. CONCLUSION The changes in muscle metabolism produced by CM treatment indicate that CM may promote aerobic energy production.
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Affiliation(s)
- D Bendahan
- Centre de Résonance Magnétique Biologique et Médicale, UMR CNRS 6612, Faculté de Médecine de la Timone, 27 Boulevard Jean Moulin, 13005 Marseille, France
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34
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Mattei JP, Kozak-Ribbens G, Roussel M, Le Fur Y, Cozzone PJ, Bendahan D. New parameters reducing the interindividual variability of metabolic changes during muscle contraction in humans. A (31)P MRS study with physiological and clinical implications. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1554:129-36. [PMID: 12034478 DOI: 10.1016/s0005-2728(02)00226-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Interindividual variations in skeletal muscle metabolism make comparative analyses difficult. In this study, we have addressed the issue of capturing the variability of metabolic performance observed during muscle exercise in humans by using an original method of normalization.Metabolic changes induced by various kinds of exercise were investigated using 31P magnetic resonance spectroscopy (MRS) at 4.7 T in 65 normal subjects (23 women and 42 men) and 12 patients with biopsy-proven muscular disorders. Large variations in the extent of PCr breakdown and intracellular acidosis were recorded among subjects and exercise protocols. For all the data pooled, the amplitude of mechanical performance accounts for 50% of these variations. When scaled to the work output, variations of PCr consumption account for 65% of pH changes through a linear relationship. This linear relationship was substantially improved (90%) when both variables were scaled to the square of work output performed (P1 and P2). By capturing most of the initial interindividual variability (90%), P1 vs. P2 relationship represents an ideal standardization procedure, independent of any anthropometric measurements. This relationship also discloses a significant link between the extent of PCr breakdown and intracellular acidosis regardless of exercise protocol. Moreover, changes in the slope of the P1 vs. P2 regression curve, as measured in old subjects and in selected patients, directly reflect alterations of energy production in muscle.
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Affiliation(s)
- Jean-Pierre Mattei
- Faculté de Médecine, Centre de Résonance Magnétique Biologique et Médicale (UMR CNRS 6612), 27 Bd J Moulin, 13005, Marseilles, France
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35
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Kemp GJ, Roberts N, Bimson WE, Bakran A, Harris PL, Gilling-Smith GL, Brennan J, Rankin A, Frostick SP. Mitochondrial function and oxygen supply in normal and in chronically ischemic muscle: a combined 31P magnetic resonance spectroscopy and near infrared spectroscopy study in vivo. J Vasc Surg 2001; 34:1103-10. [PMID: 11743568 DOI: 10.1067/mva.2001.117152] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
PURPOSE We used (31)P magnetic resonance spectroscopy (MRS) and near-infrared spectroscopy (NIRS) as a means of quantifying abnormalities in calf muscle oxygenation and adenosine triphosphate (ATP) turnover in peripheral vascular disease (PVD). METHODS Eleven male patients with PVD (mean age, 65 years; range, 55-76 years) and nine male control subjects of similar age were observed in a case-control study in vascular outpatients. Inclusion criteria were more than 6 months' calf claudication (median, 1.5 years; range, 0.6-18 years); proven femoropopliteal or iliofemoral occlusive or stenotic disease; maximum treadmill walking distance (2 km/h, 10 degrees gradient) of 50 to 230 m (mean, 112 m); ankle-brachial pressure index of 0.8 or less during exercise (mean, 0.47; range, 0.29-0.60). Exclusion criteria included diabetes mellitus, anemia, and magnet contraindications. Simultaneous (31)P MRS and NIRS of lateral gastrocnemius was conducted during 2 to 4 minutes of voluntary 0.5 Hz isometric plantarflexion at 50% and 75% maximum voluntary contraction force (MVC), followed by 5 minutes recovery. Each subject was studied three times, and the results were combined. RESULTS Compared with control subjects, patients with PVD showed (1) normal muscle cross-sectional area, MVC, ATP turnover, and contractile efficiency (ATP turnover per force/area); (2) larger phosphocreatine (PCr) changes during exercise (ie, increased shortfall of oxidative ATP synthesis) and slower PCr recovery (47% +/- 7% [mean +/- SEM] decrease in functional capacity for oxidative ATP synthesis, P = .001); (3) faster deoxygenation during exercise and slower postexercise reoxygenation (59% +/- 7% decrease in rate constant, P = .0009), despite reduced oxidative ATP synthesis; (4) correlation between PCr and NIRS recovery rate constants (P < .02); and (5) correlations between smaller walking distance, slower PCr recovery, and reduced MVC (P < .001). The precision of the key measurements (rate constants and contractile efficiency) was 12% to 18% interstudy and 30% to 40% intersubject. CONCLUSION The primary lesion in oxygen supply dominates muscle metabolism. Reduced force-generation in patients who are affected more may protect muscle from metabolic stress.
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Affiliation(s)
- G J Kemp
- Department of Musculoskeletal Science, University of Liverpool, UK.
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36
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Kemp GJ, Roussel M, Bendahan D, Le Fur Y, Cozzone PJ. Interrelations of ATP synthesis and proton handling in ischaemically exercising human forearm muscle studied by 31P magnetic resonance spectroscopy. J Physiol 2001; 535:901-28. [PMID: 11559784 PMCID: PMC2278815 DOI: 10.1111/j.1469-7793.2001.00901.x] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2000] [Accepted: 05/14/2001] [Indexed: 11/26/2022] Open
Abstract
1. In ischaemic exercise ATP is supplied only by glycogenolysis and net splitting of phosphocreatine (PCr). Furthermore, 'proton balance' involves only glycolytic lactate/H+ generation and net H+ 'consumption' by PCr splitting. This work examines the interplay between these, metabolic regulation and the creatine kinase equilibrium. 2. Nine male subjects (age 25-45 years) performed finger flexion (7 % maximal voluntary contraction at 0.67 Hz) under cuff ischaemia. 31P magnetic resonance spectra were acquired from finger flexor muscle in a 4.7 T magnet using a 5 cm surface coil. 3. Initial PCr depletion rate estimates total ATP turnover rate; glycolytic ATP synthesis was obtained from this and changes in [PCr], and then used to obtain flux through 'distal' glycolysis (phosphofructokinase and beyond) to lactate; 'proximal' flux (through phosphorylase) was obtained from this and changes in [phosphomonoester]. Total H+ load (lactate load less H+ consumption) was used to estimate cytosolic buffer capacity (beta). 4. Glycolytic ATP synthesis increased from near zero while PCr splitting declined. Net H+ load was approximately linear with pH, suggesting beta = 20 mmol x l(-1) (pH unit)(-1) at rest, increasing as pH falls. 5. Relationships between glycolytic rate and changes in [PCr] (i.e. the time-integrated mismatch between ATP use and production), and thus also [P(i)] (substrate for phosphorylase), suggest that increase in glycolysis is due partly to 'open-loop' Ca2+-dependent conversion of phosphorylase b to a, and partly to the 'closed loop' increase in P(i) consequent on net PCr splitting. 6. The 'settings' of these mechanisms have a strong influence on changes in pH and metabolite concentrations.
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Affiliation(s)
- G J Kemp
- Department of Musculoskeletal Science, University of Liverpool, Liverpool L69 3GA, UK.
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37
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Bendahan D, Kozak-Ribbens G, Confort-Gouny S, Ghattas B, Figarella-Branger D, Aubert M, Cozzone PJ. A noninvasive investigation of muscle energetics supports similarities between exertional heat stroke and malignant hyperthermia. Anesth Analg 2001; 93:683-9. [PMID: 11524341 DOI: 10.1097/00000539-200109000-00030] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Exertional heat stroke (EHS) is usually triggered by strenuous exercise performed under hot and humid environmental conditions. Although the pathogenesis of an EHS episode differs from that of a clinical malignant hyperthermia (MH) crisis, both conditions share some similarities in symptoms, such as the abnormal increase in core temperature. By use of (31)P magnetic resonance spectroscopy, we analyzed the muscle energetics of 26 post-EHS subjects for whom in vitro halothane/caffeine contracture tests were abnormal and investigated possible similarities with subjects susceptible to MH. An early decrease of pH was noted during the first minute of exercise in EHS subjects as compared with controls. EHS subjects were divided into two subgroups according to the diagnostic score previously developed for MH subjects. The 19 subjects (73%) with a score higher than 2 displayed significantly larger caffeine-induced and earlier ryanodine-induced contractures on muscle biopsies as compared with the rest of the group (7 subjects). The results demonstrate that muscle energetics are abnormal in subjects who have experienced EHS and suggest a possible link between MH and EH, although all EHS cannot be considered as MH.
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Affiliation(s)
- D Bendahan
- Centre de Résonance Magnétique Biologique et Médicale and Service d'Anatomie Pathologique, Faculté de Médecine de Marseille, Marseille, France
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38
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Simond G, Bendahan D, Cozzone PJ. Time averaging and fitting of nonlinear metabolic changes: the issue of the time index choice applied to 31P MRS investigation of muscle energetics. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2001; 149:1-7. [PMID: 11273744 DOI: 10.1006/jmre.2000.2273] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We present an exact analytical method dedicated to fitting time-dependent exponential-like changes in MR spectra. As an illustration, this method has been applied to fitting metabolic changes recorded by 31P MRS in human skeletal muscle occurring during a rest-exercise-recovery protocol. When recording metabolic changes with the accumulative method, the time averaging of the MR signals implies the choice of a time index for fitting any changes in the features of the associated MR spectra. A critical examination of the different ways (constant, linear, and exponential) of choosing the time index is reported. By numerical analysis, we have calculated the errors generated by the three methods and we have compared their sensitivity to noise. In the case of skeletal muscle, both constant and linear methods introduce large and uncontrolled errors for the whole set of metabolic parameters derived from [PCr] changes. In contrast, the exponential method affords a reliable estimation of critical parameters in muscle bioenergetics in both normal and pathological situations. This method is very easy to implement and provides an exact analytical solution to fitting changes in MR spectra recorded by the accumulative method.
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Affiliation(s)
- G Simond
- Centre de Résonance Magnétique Biologique et Médicale (CRMBM), UMR CNRS 6612, Faculté de Médecine de Marseille, 27 boulevard Jean Moulin, Marseille, 13005, France
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39
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Abstract
Phosphorus magnetic resonance spectroscopy (P-MRS) has now been used in the investigation of muscle energy metabolism in health and disease for over 15 years. The present review describes the basics of the metabolic observations made by P-MRS including the assumptions and problems associated with the use of this technique. Extramuscular factors, which may affect the P-MRS results, are detailed. The important P-MRS observations in patients with mitochondrial myopathies, including the monitoring of experimental therapies, are emphasized. The findings in other metabolic myopathies (those associated with glycolytic defects or endocrine disturbances) and in the destructive myopathies (the dystrophies and the inflammatory myopathies) are also described. Observations made in normal and abnormal fatigue, fibromyalgia, and malignant hyperthermia are considered. Finally, a summary of the possible diagnostic use of P-MRS in exercise intolerance is provided.
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Affiliation(s)
- Z Argov
- Magnetic Resonance Spectroscopy Unit, Montreal Neurological Institute, Quebec, Canada
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40
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Roussel M, Bendahan D, Mattei JP, Le Fur Y, Cozzone PJ. 31P magnetic resonance spectroscopy study of phosphocreatine recovery kinetics in skeletal muscle: the issue of intersubject variability. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1457:18-26. [PMID: 10692546 DOI: 10.1016/s0005-2728(99)00111-5] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We have analyzed by (31)P MRS the relationship between kinetic parameters of phosphocreatine (PCr) recovery and end-of-exercise status under conditions of moderate and large acidosis induced by dynamic exercise. Thirteen healthy subjects performed muscular contractions at 0.47 Hz (low frequency, moderate exercise) and 0.85 Hz (high frequency, heavy exercise). The rate constant of PCr resynthesis (k(PCr)) varied greatly among subjects (variation coefficients: 43 vs. 57% for LF vs. HF exercises) and protocols (k(PCr) values: 1.3+/-0.5 min(-1) vs. 0.9+/-0.5 min(-1) for LF vs. HF exercises, P<0.03). The large intersubject variability can be captured into a linear relationship between k(PCr), the amount of PCr consumed ([PCr(2)]) and pH reached at the end of exercise (pH(end)) (k(PCr)=-3.3+0.7 pH(end)-0.03 [PCr(2)]; P=0.0007; r=0.61). This dual relationship illustrates that mitochondrial activity is affected by end-of-exercise metabolic status and allows reliable comparisons between control, diseased and trained muscles. In contrast to k(PCr), the initial rate of PCr recovery and the maximum oxidative capacity were always constant whatever the metabolic conditions of end-of-exercise and can then be additionally used in the identification of dysfunctions in the oxidative metabolic pathway.
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Affiliation(s)
- M Roussel
- Centre de Résonance Magnétique Biologique et Médicale (CRMBM), UMR CNRS 6612, Faculté de Médecine de Marseille, 27 Boulevard Jean Moulin, 13005, Marseille, France
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41
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Larson-Meyer DE, Newcomer BR, Hunter GR, Hetherington HP, Weinsier RL. 31P MRS measurement of mitochondrial function in skeletal muscle: reliability, force-level sensitivity and relation to whole body maximal oxygen uptake. NMR IN BIOMEDICINE 2000; 13:14-27. [PMID: 10668050 DOI: 10.1002/(sici)1099-1492(200002)13:1<14::aid-nbm605>3.0.co;2-0] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The reliability, relation to whole-body maximal oxygen uptake (VO(2max)), and force-level sensitivity of (31)P MRS markers of mitochondrial function were studied in 39 normal-weight women. Following 90 s isometric plantar-flexion exercises at 45, 70 and 100% of maximum voluntary contraction, skeletal muscle mitochondrial function was determined from the phosphocreatine recovery time constant (TC(PCr)), the ADP recovery time constant (TC(ADP)), and the rate of change in PCr during the first 14 s of recovery (OxPhos). VO(2max) was measured on a treadmill. Test-retest measurements were obtained in a subset of seven women. Overall, TC(PCr), TC(ADP) and OxPhos were reproducible for all exercises (coefficients of variation = 2.3-19.3%). With increasing force-level, TC(PCr) was prolonged (29.0 +/- 8.2, 31.9 +/- 9.0 and 35.4 +/- 9.5 s), OxPhos was increased (0.159 +/- 0.081, 0.247 +/- 0.090 and 0.310 +/- 0.114), and TC(ADP) was shortened (22.4 +/- 7.9, 21.3 +/- 6.2, and 19.5 +/- 6.7; p < 0.01). All MRS markers of mitochondrial function were correlated with VO(2max) (r = 0.41-0.72; p < 0.05). These results suggest that measurements of TC(PCr), TC(ADP) and OxPhos yield reproducible results that correlate with whole-body VO(2max) and that vary in force-level sensitivity.
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Affiliation(s)
- D E Larson-Meyer
- Department of Nutrition Sciences, Division of Physiology and Metabolism, The University of Alabama at Birmingham, Birmingham, AL 35205, USA.
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42
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Heerschap A, Houtman C, in 't Zandt HJ, van den Bergh AJ, Wieringa B. Introduction to in vivo 31P magnetic resonance spectroscopy of (human) skeletal muscle. Proc Nutr Soc 1999; 58:861-70. [PMID: 10817153 DOI: 10.1017/s0029665199001160] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
31P magnetic resonance spectroscopy (MRS) offers a unique non-invasive window on energy metabolism in skeletal muscle, with possibilities for longitudinal studies and of obtaining important bioenergetic data continuously and with sufficient time resolution during muscle exercise. The present paper provides an introductory overview of the current status of in vivo 31P MRS of skeletal muscle, focusing on human applications, but with some illustrative examples from studies on transgenic mice. Topics which are described in the present paper are the information content of the 31P magnetic resonance spectrum of skeletal muscle, some practical issues in the performance of this MRS methodology, related muscle biochemistry and the validity of interpreting results in terms of biochemical processes, the possibility of investigating reaction kinetics in vivo and some indications for fibre-type heterogeneity as seen in spectra obtained during exercise.
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Affiliation(s)
- A Heerschap
- Department of Radiology, Faculty of Medical Sciences, University of Nijmegen, The Netherlands.
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43
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Haseler LJ, Hogan MC, Richardson RS. Skeletal muscle phosphocreatine recovery in exercise-trained humans is dependent on O2 availability. J Appl Physiol (1985) 1999; 86:2013-8. [PMID: 10368368 DOI: 10.1152/jappl.1999.86.6.2013] [Citation(s) in RCA: 220] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In skeletal muscle, phosphocreatine (PCr) recovery from submaximal exercise has become a reliable and accepted measure of muscle oxidative capacity. During exercise, O2 availability plays a role in determining maximal oxidative metabolism, but the relationship between O2 availability and oxidative metabolism measured by 31P-magnetic resonance spectroscopy (MRS) during recovery from exercise has never been studied. We used 31P-MRS to study exercising human gastrocnemius muscle under conditions of varied fractions of inspired O2 (FIO2) to test the hypothesis that varied O2 availability modulates PCr recovery from submaximal exercise. Six male subjects performed three bouts of 5-min steady-state submaximal plantar flexion exercise followed by 5 min of recovery in a 1.5-T magnet while breathing three different FIO2 concentrations (0.10, 0. 21, and 1.00). Under each FIO2 treatment, the PCr recovery time constants were significantly different, being longer in hypoxia [33. 5 +/- 4.1 s (SE)] and shorter in hyperoxia (20.0 +/- 1.8 s) than in normoxia (25.0 +/- 2.7 s) (P </= 0.05). End-exercise pH was not significantly different among the three treatments (7.08 +/- 0.01 for 0.10, 7.04 +/- 0.01 for 0.21, and 7.04 +/- 0.02 for 1.00). These results demonstrate that PCr recovery is significantly altered by FIO2 and suggest that, after submaximal exercise, PCr recovery, under normoxic conditions, is limited by O2 availability.
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Affiliation(s)
- L J Haseler
- Department of Medicine, University of California, San Diego, La Jolla, California 92093-0623, USA.
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44
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Mattei JP, Bendahan D, Roussel M, Lefur Y, Cozzone PJ. Gender modulates the energy cost of muscle contraction in untrained healthy subjects. A 31P magnetic resonance spectroscopy analysis. FEBS Lett 1999; 450:173-7. [PMID: 10359069 DOI: 10.1016/s0014-5793(99)00503-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The forearm flexor muscles of 56 untrained volunteers (26 women and 30 men) were examined by 31P magnetic resonance spectroscopy, during a rest-exercise-recovery protocol, in order to document the impact of gender on muscle energetics. Absolute concentrations of high-energy phosphate compounds, intracellular pH and rates of aerobic and anaerobic ATP production were calculated. An inverse correlation was found between body mass index (BMI) and power output in women but not in men. After correcting for power output and BMI, the measured energy cost of contraction was twice larger for women than for men. This increase was also reflected in larger ATP production from aerobic and anaerobic pathways. This higher energy cost might be explained in part by differences in local muscle mass, a higher impact of fatness, but also by a reduced metabolic efficiency of muscle fibers in untrained women.
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Affiliation(s)
- J P Mattei
- Centre de Résonance Magnétique Biologique et Médicale, UMR CNRS no. 6612, Faculté de Médecine de la Timone, Marseille, France
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Barbiroli B, Iotti S, Lodi R. Aspects of human bioenergetics as studied in vivo by magnetic resonance spectroscopy. Biochimie 1998; 80:847-53. [PMID: 9893943 DOI: 10.1016/s0300-9084(00)88879-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We outline the relevant capabilities of in vivo phosphorus MR spectroscopy by discussing some aspects of normal human biochemistry as studied by this technique. The transport of inorganic phosphate from cytosol into mitochondria in the human skeletal muscle was studied by exploiting a new experimental protocol. We found that Pi was transported into mitochondria in the absence of ATP biosynthesis and in the presence of a pH gradient. The control of CoQ on the efficiency of oxidative phosphorylation in the skeletal muscle and brain was studied by administering CoQ to patients with mitochondrial cytopathies due to known enzyme defects. Before CoQ we had detected a relevant reduction of mitochondrial functionality in the skeletal muscle as shown by the reduced rate of phosphocreatine recovery from exercise, and in the occipital lobes by reduced [phosphocreatine] and a high [ADP] and [Pi]. After CoQ all brain variables were remarkably improved. Treatment with CoQ also improved the rate of muscle phosphocreatine recovery from exercise. Our in vivo findings support the hypothesis that the concentration of CoQ rather than the rate of its lateral diffusion in the mitochondrial membrane controls the efficiency of oxidative phosphorylation. Other experiments were undertaken to clarify the functional relationship between cytosolic free [Mg2+] and cell bioenergetics in the intact human brain. In the same group of patients with mitochondrial cytopathies we found decreased delta G of ATP hydrolysis and low cytosolic free [Mg2+]. Treatment with CoQ resulted in improved brain bioenergetics and increased free [Mg2+]. These findings strongly indicate that decreased free magnesium was secondary to defective mitochondrial respiration, and support the hypothesis that cytosolic free [Mg2+] is regulated in the intact brain cell to equilibrate, at least in part, any changes in rapidly available free energy.
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Affiliation(s)
- B Barbiroli
- Dipartimento di Medicina Clinica e Biotecnologia Applicata (D Campanacci), Bologna, Italy
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Bendahan D, Kozak-Ribbens G, Confort-Gouny S, Cozzone PJ. [Malignant hyperthermia and NMR31P spectroscopy: authors answer]. ANNALES FRANCAISES D'ANESTHESIE ET DE REANIMATION 1998; 16:76-7. [PMID: 9686106 DOI: 10.1016/s0750-7658(97)84288-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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Erkintalo M, Bendahan D, Mattéi JP, Fabreguettes C, Vague P, Cozzone PJ. Reduced metabolic efficiency of skeletal muscle energetics in hyperthyroid patients evidenced quantitatively by in vivo phosphorus-31 magnetic resonance spectroscopy. Metabolism 1998; 47:769-76. [PMID: 9667219 DOI: 10.1016/s0026-0495(98)90110-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Skeletal muscle energetics of seven hyperthyroid patients were investigated throughout a rest-exercise-recovery protocol using phosphorus-31 magnetic resonance spectroscopy (31P MRS) to quantitatively document in vivo the metabolic bases of impaired muscle performance in hyperthyroidism. The contributions of the main pathways of adenosine triphosphate (ATP) synthesis to energy production and proton efflux were measured and compared with results from normal muscle. At rest, a reduced concentration of phosphocreatine (PCr) was calculated for hyperthyroid patients when compared with controls, whereas pH and concentrations of inorganic phosphate (Pi) and phosphomonoesters (PME) were not different from controls. During exercise, the analysis of changes in pH and PCr concentration demonstrated that (1) at the onset of exercise, the magnitude of glycolysis activation is significantly larger for patients, resulting in a marked pH decrease; (2) the energy cost of exercise is higher for patients as compared with controls performing the same amount of work; and (3) both anaerobic and aerobic pathways are significantly more activated in the hyperthyroid group throughout the 3 minutes of exercise. During recovery, the rates of proton efflux and PCr resynthesis were similar in both groups, excluding any alteration in oxidative function and proton handling as a cause of initial glycolytic hyperactivation. The increased energy cost measured for patients during exercise evidences an increased need for energy, which is (1) probably linked to the existence of additional ATP-consuming mechanism(s), and (2) supported by hyperactivation of both aerobic and anaerobic pathways. These findings imply that, all things equal, a hyperthyroid muscle requires more energy to function than normal, and as a result is potentially more fatiguable.
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Affiliation(s)
- M Erkintalo
- Centre de Résonance Magnétique Biologique et Médicale, UMR CNRS no. 6612, Faculté de Médecine, Marseille, France
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Mattei JP, Bendahan D, Erkintalo M, Harle JR, Weiller PJ, Roux H, Cozzone PJ. P-31 magnetic resonance spectroscopy demonstrates unaltered muscle energy utilization in polymyalgia rheumatica. ARTHRITIS AND RHEUMATISM 1997; 40:1817-22. [PMID: 9336416 DOI: 10.1002/art.1780401014] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
OBJECTIVE To characterize muscle metabolic anomalies associated with polymyalgia rheumatica (PMR) using P-31 magnetic resonance spectroscopy (MRS). METHODS Seventeen patients with PMR and 9 age-matched control subjects were investigated. The forearm flexor muscles were examined by P-31 MRS in a 4.7 T superconducting horizontal magnet (Biospec Bruker 47/30) during a rest-exercise-recovery protocol. The intracellular pH and the relative concentrations of phosphocreatine (PCr), inorganic phosphate (Pi), ATP, and phosphomonoesters were measured every minute during the protocol. Based on the PCr and pH time-dependent changes during exercise and recovery, the rates of ATP production from PCr hydrolysis, glycogenolysis, and aerobic metabolism were calculated for each minute of exercise. RESULTS At rest, the metabolic parameters [PCr]:[Pi], pH, and [PCr]:[ATP] were not significantly different between the PMR patients and the control subjects. During exercise, the energetic cost and the contribution of anaerobic and oxidative pathways to energy supply were similar in the 2 groups, as were the recovery kinetics of the phosphorylated compounds and pH. CONCLUSION Muscle MRS does not confirm the findings of histologic and biochemical studies that suggest an alteration of mitochondrial function in PMR. No other modifications in glycolytic or glycogenolytic pathways or in proton handling were found that could indicate an alteration of muscle energetics in patients with PMR.
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Affiliation(s)
- J P Mattei
- Centre de Résonance Magnétique Biologique et Médicale, and Faculté de Médecine de la Timone, Marseille, France
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Lodi R, Kemp GJ, Iotti S, Radda GK, Barbiroli B. Influence of cytosolic pH on in vivo assessment of human muscle mitochondrial respiration by phosphorus magnetic resonance spectroscopy. MAGMA (NEW YORK, N.Y.) 1997; 5:165-71. [PMID: 9268081 DOI: 10.1007/bf02592248] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The authors present an in vivo phosphorus magnetic resonance spectroscopy systematic study on the effects of cytosolic pH on skeletal muscle mitochondrial respiration in human calf muscle. In 49 normal subjects, the effect of cytosolic pH on kinetics of phosphocreatine and adenosine diphosphate recovery and on maximum rate of mitochondrial adenosine triphosphate production (Q(MAX)) was evaluated. The results show a strong relationship between the rate of postexercise phosphocreatine recovery and the lowest value of cytosolic pH reached during recovery from exercise (termed minimum pH; r = 0.89); in contrast, both adenosine diphosphate recovery halftime and Q(MAX) were independent of cytosolic pH at the end of exercise.
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Affiliation(s)
- R Lodi
- Cattedra di Biochimica Clinica, Dipartimento di Medicina Clinica e Biotecnologia Applicata D. Campanacci, Universitá di Bologna, Italy
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Toussaint JF, Kwong KK, M'Kparu F, Weisskoff RM, LaRaia PJ, Kantor HL. Interrelationship of oxidative metabolism and local perfusion demonstrated by NMR in human skeletal muscle. J Appl Physiol (1985) 1996; 81:2221-8. [PMID: 8941548 DOI: 10.1152/jappl.1996.81.5.2221] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Using nuclear magnetic resonance (NMR), we have examined the relationship of high-energy phosphate metabolism and perfusion in human soleus and gastrocnemius muscles. With 31P-NMR spectroscopy, we monitored phosphocreatine (PCr) decay and recovery in eight normal volunteers and four heart failure patients performing ischemic plantar flexion. By using echo-planar imaging, perfusion was independently measured by a local [inversion-recovery (T1-flow)] and a regional technique (NMR-plethysmography). After correction for its pH dependence, PCr recovery time constant is 27.5 +/- 8.0 s in normal volunteers, with mean flow 118 +/- 75 (soleus and gastrocnemius T1-flow) and 30.2 +/- 9.7 ml.100 ml-1.min-1 (NMR-plethysmography-flow). We demonstrate a positive correlation between PCr time constant and local perfusion given by y = 50 - 0.15x (r2 = 0.68, P = 0.01) for the 8 normal subjects, and y = 64 - 0.24x (r2 = 0.83, P = 0.0001) for the 12 subjects recruited in the study. Regional perfusion techniques also show a significant but weaker correlation. Using this totally noninvasive method, we conclude that aerobic ATP resynthesis is related to the magnitude of perfusion, i.e., O2 availability, and demonstrate that magnetic resonance imaging and magnetic resonance spectroscopy together can accurately assess muscle functional status.
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Affiliation(s)
- J F Toussaint
- Commissariat à l'Energie Atomique-Service Hospitalier Frédéric Joliot, Orsay, France.
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