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Koutlas A, Smilios I, Kokkinou EM, Myrkos A, Kounoupis A, Dipla K, Zafeiridis A. NIRS-Derived Muscle-Deoxygenation and Microvascular Reactivity During Occlusion-Reperfusion at Rest Are Associated With Whole-Body Aerobic Fitness. RESEARCH QUARTERLY FOR EXERCISE AND SPORT 2024; 95:127-139. [PMID: 36689603 DOI: 10.1080/02701367.2022.2159309] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 12/12/2022] [Indexed: 06/17/2023]
Abstract
Purpose: Near-infrared spectroscopy (NIRS) indices during arterial occlusion-reperfusion maneuver have been used to examine the muscle's oxidative metabolism and microvascular function-important determinants of whole-body aerobic-fitness. The association of NIRS-derived parameters with whole-body VO2max was previously examined using a method requiring exercise (or electrical stimulation) followed by multiple arterial occlusions. We examined whether NIRS-derived indices of muscle deoxygenation and microvascular reactivity assessed during a single occlusion-reperfusion at rest are (a) associated with maximal/submaximal indices of whole-body aerobic-fitness and (b) could discriminate individuals with different VO2max. We, also, investigated which NIRS-parameter during occlusion-reperfusion correlates best with whole-body aerobic-fitness. Methods: Twenty-five young individuals performed an arterial occlusion-reperfusion at rest. Changes in oxygenated- and deoxygenated-hemoglobin (O2Hb and HHb, respectively) in vastus-lateralis were monitored; adipose tissue thickness (ATT) at NIRS-application was assessed. Participants also underwent a maximal incremental exercise test for VO2max, maximal aerobic velocity (MAV), and ventilatory-thresholds (VTs) assessments. Results: The HHbslope and HHbmagnitude of increase (occlusion-phase) and O2Hbmagnitude of increase (reperfusion-phase) were strongly correlated with VO2max (r = .695-.763, p < .001) and moderately with MAV (r = .468-.530; p < .05). O2Hbmagnitude was moderately correlated with VTs (r = .399-.414; p < .05). After controlling for ATT, the correlations remained significant for VO2max (r = .672-.704; p < .001) and MAV (r = .407; p < .05). Individuals in the high percentiles after median and tritile splits for HHbslope and O2Hbmagnitude had significantly greater VO2max vs. those in low percentiles (p < .01-.05). The HHbslope during occlusion was the best predictor of VO2max. Conclusion: NIRS-derived muscle deoxygenation/reoxygenation indices during a single arterial occlusion-reperfusion maneuver are strongly associated with whole-body maximal indices of aerobic-fitness (VO2max, MAV) and may discriminate individuals with different VO2max.
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Hadjispyrou S, Giannopoulos A, Philippou A, Theos A. Mitochondrial Dysfunction and Sarcopenic Obesity: The Role of Exercise. J Clin Med 2023; 12:5628. [PMID: 37685695 PMCID: PMC10489005 DOI: 10.3390/jcm12175628] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 08/16/2023] [Accepted: 08/21/2023] [Indexed: 09/10/2023] Open
Abstract
Sarcopenic obesity (SO) constitutes the coexistence of skeletal muscle mass loss (sarcopenia) and excess adiposity (obesity). It is mainly considered as a condition in the elderly with health-threatening impacts ranging from frailty to mortality. Mitochondrial dysfunction consists one of the basic pathophysiological mechanisms leading to the development of SO and its consequences. Indirect indicators of mitochondrial function, such as VO2max and exercise capacity, have been demonstrated to be negatively affected in individuals with SO, while the positive effect of exercise on mitochondrial function has been widely proved; thus, in this review, we aimed at investigating the effects of endurance, resistance, and concurrent exercise training on indexes of mitochondrial dysfunction in SO patients. The results of the clinical trials evaluated reveal positive effects of chronic exercise on VO2max and physical capacity, as well as mitochondrial biogenesis and activity. It has been concluded that utilizing a systematic exercise training program that includes both aerobic and strength exercises can be an effective strategy for managing SO and promoting overall health in these patients.
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Affiliation(s)
- Spyridon Hadjispyrou
- Section of Sports Medicine, Department of Community Medicine and Rehabilitation, Umeå University, 901 87 Umeå, Sweden;
- Umeå School of Sports Sciences, Umeå University, 901 87 Umeå, Sweden;
| | - Antonios Giannopoulos
- Umeå School of Sports Sciences, Umeå University, 901 87 Umeå, Sweden;
- Department of Surgical & Perioperative Sciences, Umeå University, 901 87 Umeå, Sweden
| | - Anastassios Philippou
- Department of Physiology, Medical School, National and Kapodistrian University of Athens, 157 72 Athens, Greece;
| | - Apostolos Theos
- Section of Sports Medicine, Department of Community Medicine and Rehabilitation, Umeå University, 901 87 Umeå, Sweden;
- Umeå School of Sports Sciences, Umeå University, 901 87 Umeå, Sweden;
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3
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Oberdier MT, AlGhatrif M, Adelnia F, Zampino M, Morrell CH, Simonsick E, Fishbein K, Lakatta EG, McDermott MM, Ferrucci L. Ankle-Brachial Index and Energy Production in People Without Peripheral Artery Disease: The BLSA. J Am Heart Assoc 2022; 11:e019014. [PMID: 35253449 PMCID: PMC9075330 DOI: 10.1161/jaha.120.019014] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 10/04/2021] [Indexed: 11/16/2022]
Abstract
Background Lower ankle-brachial index (ABI) values within the 0.90 to 1.40 range are associated with poorer mitochondrial oxidative capacity of thigh muscles in cross-sectional analyses. Whether ABI decline is associated with greater declines in thigh muscle oxidative capacity with aging is unknown. Method and Results We analyzed data from 228 participants (100 men) of the BLSA (Baltimore Longitudinal Study of Aging), aged 39 to 97 years, with an ABI between 0.9 and 1.40 at baseline and at follow-up (mean follow-up period of 2.8 years). We examined mitochondrial oxidative capacity of the left thigh muscle, by measuring the postexercise phosphocreatine recovery rate constant (kPCr) from phosphorus-31 magnetic resonance spectroscopy. Greater kPCr indicated higher mitochondrial oxidative capacity. Although kPCr was available on the left leg only, ABI was measured in both legs. Longitudinal rates of change (Change) of left and right ABI and kPCr of the left thigh muscle were estimated using linear mixed effects models, and their association was analyzed by standardized multiple linear regressions. In multivariate analysis including sex, age, baseline kPCr, both left and right baseline ABI, and ABI change in both legs, (kPCr)Change was directly associated with ipsilateral (left) (ABI)Change (standardized [STD]-β=0.14; P=0.0168) but not with contralateral (right) (ABI)Change (P=0.22). Adjusting for traditional cardiovascular risk factors, this association remained significant (STD-β=0.18; P=0.0051). (kPCr)Change was steeper in White race participants (STD-β=0.16; P=0.0122) and body mass index (STD-β=0.13; P=0.0479). There was no significant association with current smoking status (P=0.63), fasting glucose (P=0.28), heart rate (P=0.67), mean blood pressure (P=0.78), and low-density lipoprotein (P=0.75), high-density lipoprotein (P=0.82), or triglycerides (P=0.15). Conclusions In people without peripheral arterial disease, greater decline in ABI over time, but not baseline ABI, was associated with faster decline in thigh mitochondrial oxidative capacity in the ipsilateral leg. Further studies are needed to examine whether early interventions that improve lower extremity muscle perfusion can improve and prevent the decline of muscle energetics.
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Affiliation(s)
- Matt T. Oberdier
- Laboratory of Cardiovascular ScienceNational Institute on AgingBaltimoreMD
- Longitudinal Studies SectionNational Institute on AgingBaltimoreMD
| | - Majd AlGhatrif
- Laboratory of Cardiovascular ScienceNational Institute on AgingBaltimoreMD
- Longitudinal Studies SectionNational Institute on AgingBaltimoreMD
- Department of MedicineJohns Hopkins School of MedicineBaltimoreMD
| | - Fatemeh Adelnia
- Longitudinal Studies SectionNational Institute on AgingBaltimoreMD
| | - Marta Zampino
- Longitudinal Studies SectionNational Institute on AgingBaltimoreMD
| | - Christopher H. Morrell
- Laboratory of Cardiovascular ScienceNational Institute on AgingBaltimoreMD
- Loyola University MarylandBaltimoreMD
| | | | - Kenneth Fishbein
- Laboratory of Clinical InvestigationNational Institute on AgingBaltimoreMD
| | - Edward G. Lakatta
- Laboratory of Cardiovascular ScienceNational Institute on AgingBaltimoreMD
| | - Mary M. McDermott
- Department of MedicineNorthwestern University Feinberg School of MedicineChicagoIL
| | - Luigi Ferrucci
- Longitudinal Studies SectionNational Institute on AgingBaltimoreMD
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4
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Active Women Across the Lifespan: Nutritional Ingredients to Support Health and Wellness. Sports Med 2022; 52:101-117. [PMID: 36173598 PMCID: PMC9521557 DOI: 10.1007/s40279-022-01755-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/17/2022] [Indexed: 12/15/2022]
Abstract
Women are the largest consumers of dietary supplements. Dietary supplements can play a role in health and performance, particularly for women. Growing evidence and innovations support the unique physiological and nutrient timing needs for women. Despite the need for more nutrition and exercise-specific research in women, initial data and known physiological differences between sexes related to the brain, respiration, bone, and muscle support new product development and evidence-based education for active women regarding the use of dietary supplements. In this narrative review, we discuss hormonal and metabolic considerations with the potential to impact nutritional recommendations for active women. We propose four potential areas of opportunity for ingredients to help support the health and well-being of active women, including: (1) body composition, (2) energy/fatigue, (3) mental health, and (4) physical health.
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5
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Lagerwaard B, Janssen JJE, Cuijpers I, Keijer J, de Boer VCJ, Nieuwenhuizen AG. Muscle mitochondrial capacity in high- and low-fitness females using near-infrared spectroscopy. Physiol Rep 2021; 9:e14838. [PMID: 33991439 PMCID: PMC8123566 DOI: 10.14814/phy2.14838] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 03/09/2021] [Accepted: 03/12/2021] [Indexed: 11/24/2022] Open
Abstract
The recovery of muscle oxygen consumption (m V ˙ O2 ) after exercise measured using near-infrared spectroscopy (NIRS) provides a measure of skeletal muscle mitochondrial capacity. Nevertheless, due to sex differences in factors that can influence scattering and thus penetration depth of the NIRS signal in the tissue, e.g., subcutaneous adipose tissue thickness and intramuscular myoglobin and hemoglobin, it is unknown whether results in males can be extrapolated to a female population. Therefore, the aim of this study was to measure skeletal muscle mitochondrial capacity in females at different levels of aerobic fitness to test whether NIRS can measure relevant differences in mitochondrial capacity. Mitochondrial capacity was analyzed in the gastrocnemius muscle and the wrist flexors of 32 young female adults, equally divided in relatively high ( V ˙ O2 peak ≥ 47 ml/kg/min) and relatively low aerobic fitness group ( V ˙ O2 peak ≤ 37 ml/kg/min). m V ˙ O2 recovery was significantly faster in the high- compared to the low-fitness group in the gastrocnemius, but not in the wrist flexors (p = 0.009 and p = 0.0528, respectively). Furthermore, V ˙ O2 peak was significantly correlated to m V ˙ O2 recovery in both gastrocnemius (R2 = 0.27, p = 0.0051) and wrist flexors (R2 = 0.13, p = 0.0393). In conclusion, NIRS measurements can be used to assess differences in mitochondrial capacity within a female population and is correlated to V ˙ O2 peak. This further supports NIRS assessment of muscle mitochondrial capacity providing additional evidence for NIRS as a promising approach to monitor mitochondrial capacity, also in an exclusively female population.
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Affiliation(s)
- Bart Lagerwaard
- Human and Animal Physiology, Wageningen University and Research, Wageningen, The Netherlands.,TI Food and Nutrition, Wageningen, The Netherlands
| | - Joëlle J E Janssen
- Human and Animal Physiology, Wageningen University and Research, Wageningen, The Netherlands
| | - Iris Cuijpers
- Human and Animal Physiology, Wageningen University and Research, Wageningen, The Netherlands
| | - Jaap Keijer
- Human and Animal Physiology, Wageningen University and Research, Wageningen, The Netherlands
| | - Vincent C J de Boer
- Human and Animal Physiology, Wageningen University and Research, Wageningen, The Netherlands
| | - Arie G Nieuwenhuizen
- Human and Animal Physiology, Wageningen University and Research, Wageningen, The Netherlands
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6
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Pataky MW, Young WF, Nair KS. Hormonal and Metabolic Changes of Aging and the Influence of Lifestyle Modifications. Mayo Clin Proc 2021; 96:788-814. [PMID: 33673927 PMCID: PMC8020896 DOI: 10.1016/j.mayocp.2020.07.033] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 06/01/2020] [Accepted: 07/02/2020] [Indexed: 02/07/2023]
Abstract
Increased life expectancy combined with the aging baby boomer generation has resulted in an unprecedented global expansion of the elderly population. The growing population of older adults and increased rate of age-related chronic illness has caused a substantial socioeconomic burden. The gradual and progressive age-related decline in hormone production and action has a detrimental impact on human health by increasing risk for chronic disease and reducing life span. This article reviews the age-related decline in hormone production, as well as age-related biochemical and body composition changes that reduce the bioavailability and actions of some hormones. The impact of hormonal changes on various chronic conditions including frailty, diabetes, cardiovascular disease, and dementia are also discussed. Hormone replacement therapy has been attempted in many clinical trials to reverse and/or prevent the hormonal decline in aging to combat the progression of age-related diseases. Unfortunately, hormone replacement therapy is not a panacea, as it often results in various adverse events that outweigh its potential health benefits. Therefore, except in some specific individual cases, hormone replacement is not recommended. Rather, positive lifestyle modifications such as regular aerobic and resistance exercise programs and/or healthy calorically restricted diet can favorably affect endocrine and metabolic functions and act as countermeasures to various age-related diseases. We provide a critical review of the available data and offer recommendations that hopefully will form the groundwork for physicians/scientists to develop and optimize new endocrine-targeted therapies and lifestyle modifications that can better address age-related decline in heath.
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Affiliation(s)
- Mark W Pataky
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, MN
| | - William F Young
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, MN
| | - K Sreekumaran Nair
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, MN.
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7
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Scalzo RL, Schauer IE, Rafferty D, Knaub LA, Kvaratskhelia N, Johnson TK, Pott GB, Abushamat LA, Whipple MO, Huebschmann AG, Cree-Green M, Reusch JEB, Regensteiner JG. Single-leg exercise training augments in vivo skeletal muscle oxidative flux and vascular content and function in adults with type 2 diabetes. J Physiol 2021; 600:963-978. [PMID: 33569797 DOI: 10.1113/jp280603] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 01/28/2021] [Indexed: 12/14/2022] Open
Abstract
KEY POINTS People with type 2 diabetes (T2D) have impaired skeletal muscle oxidative flux due to limited oxygen delivery. In the current study, this impairment in oxidative flux in people with T2D was abrogated with a single-leg exercise training protocol. Additionally, single-leg exercise training increased skeletal muscle CD31 content, calf blood flow and state 4 mitochondrial respiration in all participants. ABSTRACT Cardiorespiratory fitness is impaired in type 2 diabetes (T2D), conferring significant cardiovascular risk in this population; interventions are needed. Previously, we reported that a T2D-associated decrement in skeletal muscle oxidative flux is ameliorated with acute use of supplemental oxygen, suggesting that skeletal muscle oxygenation is rate-limiting to in vivo mitochondrial oxidative flux during exercise in T2D. We hypothesized that single-leg exercise training (SLET) would improve the T2D-specific impairment in in vivo mitochondrial oxidative flux during exercise. Adults with (n = 19) and without T2D (n = 22) with similar body mass indexes and levels of physical activity participated in two weeks of SLET. Following SLET, in vivo oxidative flux measured by 31 P-MRS increased in participants with T2D, but not people without T2D, measured by the increase in initial phosphocreatine synthesis (P = 0.0455 for the group × exercise interaction) and maximum rate of oxidative ATP synthesis (P = 0.0286 for the interaction). Additionally, oxidative phosphorylation increased in all participants with SLET (P = 0.0209). After SLET, there was no effect of supplemental oxygen on any of the in vivo oxidative flux measurements in either group (P > 0.02), consistent with resolution of the T2D-associated oxygen limitation previously observed at baseline in subjects with T2D. State 4 mitochondrial respiration also improved in muscle fibres ex vivo. Skeletal muscle vasculature content and calf blood flow increased in all participants with SLET (P < 0.0040); oxygen extraction in the calf increased only in T2D (P = 0.0461). SLET resolves the T2D-associated impairment of skeletal muscle in vivo mitochondrial oxidative flux potentially through improved effective blood flow/oxygen delivery.
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Affiliation(s)
- Rebecca L Scalzo
- Division of Endocrinology, University of Colorado School of Medicine, Aurora, Colorado, USA.,Division of Center for Women's Health Research, Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado, USA.,Rocky Mountain Regional Veterans Administration Medical Center, Aurora, Colorado, USA
| | - Irene E Schauer
- Division of Endocrinology, University of Colorado School of Medicine, Aurora, Colorado, USA.,Rocky Mountain Regional Veterans Administration Medical Center, Aurora, Colorado, USA
| | - Deirdre Rafferty
- Division of General Internal Medicine, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Leslie A Knaub
- Division of Endocrinology, University of Colorado School of Medicine, Aurora, Colorado, USA.,Rocky Mountain Regional Veterans Administration Medical Center, Aurora, Colorado, USA
| | - Nina Kvaratskhelia
- Division of Endocrinology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Taro Kaelix Johnson
- Division of Endocrinology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Gregory B Pott
- Division of Endocrinology, University of Colorado School of Medicine, Aurora, Colorado, USA.,Rocky Mountain Regional Veterans Administration Medical Center, Aurora, Colorado, USA
| | - Layla A Abushamat
- Division of Endocrinology, University of Colorado School of Medicine, Aurora, Colorado, USA.,Rocky Mountain Regional Veterans Administration Medical Center, Aurora, Colorado, USA
| | - Mary O Whipple
- Division of General Internal Medicine, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Amy G Huebschmann
- Division of General Internal Medicine, University of Colorado School of Medicine, Aurora, Colorado, USA.,Division of Center for Women's Health Research, Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Melanie Cree-Green
- Division of Center for Women's Health Research, Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado, USA.,Division of Pediatric Endocrinology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Jane E B Reusch
- Division of Endocrinology, University of Colorado School of Medicine, Aurora, Colorado, USA.,Division of General Internal Medicine, University of Colorado School of Medicine, Aurora, Colorado, USA.,Division of Center for Women's Health Research, Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado, USA.,Rocky Mountain Regional Veterans Administration Medical Center, Aurora, Colorado, USA
| | - Judith G Regensteiner
- Division of General Internal Medicine, University of Colorado School of Medicine, Aurora, Colorado, USA.,Division of Center for Women's Health Research, Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado, USA
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8
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Lopez Kolkovsky AL, Marty B, Giacomini E, Meyerspeer M, Carlier PG. Repeatability of multinuclear interleaved acquisitions with nuclear Overhauser enhancement effect in dynamic experiments in the calf muscle at 3T. Magn Reson Med 2021; 86:115-130. [PMID: 33565187 DOI: 10.1002/mrm.28684] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 12/23/2020] [Accepted: 12/23/2020] [Indexed: 02/01/2023]
Abstract
PURPOSE To evaluate the repeatability of multinuclear interleaved 1 H/31 P NMR dynamic acquisitions in skeletal muscle and the impact of nuclear Overhauser enhancement (nOe) on the 31 P results at 3T in exercise-recovery and ischemia-hyperemia paradigms. METHODS A 1 H/31 P interleaved pulse sequence was used to measure every 2.5 s a perfusion-weighted image, a T 2 ∗ map, a 31 P spectrum and 32 1 H spectra sensitive to deoxymyoglobin. 21 subjects performed a plantar flexion exercise and after recovery underwent an 8-min lower leg ischemia. The procedure was repeated in visit 2 with 12 subjects. An additional exercise bout without 1 H excitation was appended to visit 1. Individual 1 H RF pulse nOe was measured at rest in every visit. RESULTS Repeatability scores (coefficient of variation, Bland-Altman analysis) were similar to those found in the literature using similar mono-nuclear acquisitions. |Pi]/[PCr], pH drop, creatine rephosphorylation rate (τPCr ), maximum perfusion, time to peak perfusion, and blood flow post-exercise showed high reliability (intraclass correlation coefficient > 0.7), whereas hemodynamic results from reactive hyperemia showed higher repeatability. After accounting for nOe, which increased Pi and PCr signal-to-noise ratio by 30%, no differences in 31 P results were observed between interleaved and 31 P MRS-only acquisitions. τPCr was unaffected by nOe. CONCLUSION The method shows good repeatability for both paradigms while simultaneously providing multiple dynamic data sets on a clinical scanner. The nOe effects were accounted for on a per-subject and per-visit basis using a short 31 P reference scan. This multiparametric approach has a multitude of applications for the study of oxygen utilization and ATP turnover in the muscle.
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Affiliation(s)
- Alfredo L Lopez Kolkovsky
- NMR Laboratory, Neuromuscular Investigation Center, Institute of Myology, Paris, France.,NMR Laboratory, CEA, DRF, IBFJ, MIRCen, Paris, France
| | - Benjamin Marty
- NMR Laboratory, Neuromuscular Investigation Center, Institute of Myology, Paris, France.,NMR Laboratory, CEA, DRF, IBFJ, MIRCen, Paris, France
| | - Eric Giacomini
- NMR Laboratory, Neuromuscular Investigation Center, Institute of Myology, Paris, France
| | - Martin Meyerspeer
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Pierre G Carlier
- NMR Laboratory, Neuromuscular Investigation Center, Institute of Myology, Paris, France.,NMR Laboratory, CEA, DRF, IBFJ, MIRCen, Paris, France
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Beever AT, Tripp TR, Zhang J, MacInnis MJ. NIRS-derived skeletal muscle oxidative capacity is correlated with aerobic fitness and independent of sex. J Appl Physiol (1985) 2020; 129:558-568. [PMID: 32702279 PMCID: PMC7517427 DOI: 10.1152/japplphysiol.00017.2020] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 06/26/2020] [Accepted: 07/19/2020] [Indexed: 01/03/2023] Open
Abstract
Near-infrared spectroscopy (NIRS) provides a simple and reliable measure of skeletal muscle oxidative capacity; however, its relationship to aerobic fitness and sex are unclear. We hypothesized that NIRS-derived oxidative capacity in the vastus lateralis (VL) and medial gastrocnemius (MG) would be correlated with indices of aerobic fitness and independent of sex. Twenty-six participants (13 males, 13 females) performed ramp- and step-incremental tests to volitional exhaustion on separate days to establish maximal oxygen uptake (V̇o2max), peak power output (PPO), lactate threshold (LT), gas exchange threshold (GET), respiratory compensation point (RCP), and maximal fat oxidation (MFO). Data were normalized to lean body mass to account for sex-based differences in body composition. Exercise tests were preceded by duplicate measurements of NIRS-derived oxidative capacity on the VL and MG muscles (i.e., repeated arterial occlusions following a brief set of muscle contractions). Skeletal muscle oxidative capacity for the VL (means ± SD: 21.9 ± 4.6 s) and MG (22.5 ± 6.1 s) were similar but unrelated (r2 = 0.03, P = 0.39). Skeletal muscle oxidative capacity for the VL, but not the MG (P > 0.05 for all variables), was significantly correlated with V̇o2max (r2 = 0.24; P = 0.01), PPO (r2 = 0.23; P = 0.01), LT (r2 = 0.23; P = 0.01), GET (r2 = 0.23; P = 0.01), and RCP (r2 = 0.27; P = 0.006). MFO was not correlated with VL or MG skeletal muscle oxidative capacity (P > 0.05). Females (54.9 ± 4.5 mL·kg LBM-1·min-1) and males (56.0 ± 6.2 mL·kg LBM-1·min-1), matched for V̇o2max (P = 0.62), had similar NIRS-derived oxidative capacities for VL (20.7 ± 4.4 vs. 23.2 ± 4.6 s; P = 0.18) and MG (24.4 ± 6.8 vs. 20.5 ± 4.8 s; P = 0.10). Overall, NIRS-derived skeletal muscle oxidative capacity in VL is indicative of aerobic fitness and independent of sex in humans.NEW & NOTEWORTHY Near-infrared spectroscopy (NIRS) can be used to measure skeletal muscle oxidative capacity. Here, we demonstrated that NIRS-derived skeletal muscle oxidative capacity of the vastus lateralis was independent of sex, reliable across and within days, and correlated with maximal and submaximal indices of aerobic fitness, including maximal oxygen uptake, lactate threshold, and respiratory compensation point. These findings highlight the utility of NIRS for investigating skeletal muscle oxidative capacity in females and males.
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Affiliation(s)
- Austin T Beever
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Thomas R Tripp
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Jenny Zhang
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Martin J MacInnis
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
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10
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Kestenbaum B, Gamboa J, Liu S, Ali AS, Shankland E, Jue T, Giulivi C, Smith LR, Himmelfarb J, de Boer IH, Conley K, Roshanravan B. Impaired skeletal muscle mitochondrial bioenergetics and physical performance in chronic kidney disease. JCI Insight 2020; 5:133289. [PMID: 32161192 PMCID: PMC7141399 DOI: 10.1172/jci.insight.133289] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 12/10/2019] [Indexed: 11/17/2022] Open
Abstract
The maintenance of functional independence is the top priority of patients with chronic kidney disease (CKD). Defects in mitochondrial energetics may compromise physical performance and independence. We investigated associations of the presence and severity of kidney disease with in vivo muscle energetics and the association of muscle energetics with physical performance. We performed measures of in vivo leg and hand muscle mitochondrial capacity (ATPmax) and resting ATP turnover (ATPflux) using 31phosphorus magnetic resonance spectroscopy and oxygen uptake (O2 uptake) by optical spectroscopy in 77 people (53 participants with CKD and 24 controls). We measured physical performance using the 6-minute walk test. Participants with CKD had a median estimated glomerular filtration rate (eGFR) of 33 ml/min per 1.73 m2. Participants with CKD had a -0.19 mM/s lower leg ATPmax compared with controls but no difference in hand ATPmax. Resting O2 uptake was higher in CKD compared with controls, despite no difference in ATPflux. ATPmax correlated with eGFR and serum bicarbonate among participants with GFR <60. ATPmax of the hand and leg correlated with 6-minute walking distance. The presence and severity of CKD associate with muscle mitochondrial capacity. Dysfunction of muscle mitochondrial energetics may contribute to reduced physical performance in CKD.
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Affiliation(s)
- Bryan Kestenbaum
- Division of Nephrology, Department of Medicine, and
- Kidney Research Institute, University of Washington, Seattle, Washington, USA
| | - Jorge Gamboa
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Sophia Liu
- Department of Radiology, University of Washington, Seattle, Washington, USA
| | - Amir S. Ali
- Department of Radiology, University of Washington, Seattle, Washington, USA
| | - Eric Shankland
- Department of Radiology, University of Washington, Seattle, Washington, USA
| | - Thomas Jue
- Department of Biochemistry and Molecular Medicine, School of Medicine
| | - Cecilia Giulivi
- Department of Molecular Biosciences, School of Veterinary Medicine, and
| | - Lucas R. Smith
- Department of Physical Medicine and Rehabilitation, School of Medicine, UCD, Davis, California, USA
| | - Jonathan Himmelfarb
- Division of Nephrology, Department of Medicine, and
- Kidney Research Institute, University of Washington, Seattle, Washington, USA
| | - Ian H. de Boer
- Division of Nephrology, Department of Medicine, and
- Kidney Research Institute, University of Washington, Seattle, Washington, USA
- Puget Sound Veterans Administration Healthcare System, Seattle, Washington, USA
| | - Kevin Conley
- Department of Radiology, University of Washington, Seattle, Washington, USA
| | - Baback Roshanravan
- Division of Nephrology, Department of Medicine, School of Medicine, UCD, Sacramento, California, USA
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11
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Meyerspeer M, Boesch C, Cameron D, Dezortová M, Forbes SC, Heerschap A, Jeneson JA, Kan HE, Kent J, Layec G, Prompers JJ, Reyngoudt H, Sleigh A, Valkovič L, Kemp GJ. 31 P magnetic resonance spectroscopy in skeletal muscle: Experts' consensus recommendations. NMR IN BIOMEDICINE 2020; 34:e4246. [PMID: 32037688 PMCID: PMC8243949 DOI: 10.1002/nbm.4246] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Revised: 12/01/2019] [Accepted: 12/02/2019] [Indexed: 05/07/2023]
Abstract
Skeletal muscle phosphorus-31 31 P MRS is the oldest MRS methodology to be applied to in vivo metabolic research. The technical requirements of 31 P MRS in skeletal muscle depend on the research question, and to assess those questions requires understanding both the relevant muscle physiology, and how 31 P MRS methods can probe it. Here we consider basic signal-acquisition parameters related to radio frequency excitation, TR, TE, spectral resolution, shim and localisation. We make specific recommendations for studies of resting and exercising muscle, including magnetisation transfer, and for data processing. We summarise the metabolic information that can be quantitatively assessed with 31 P MRS, either measured directly or derived by calculations that depend on particular metabolic models, and we give advice on potential problems of interpretation. We give expected values and tolerable ranges for some measured quantities, and minimum requirements for reporting acquisition parameters and experimental results in publications. Reliable examination depends on a reproducible setup, standardised preconditioning of the subject, and careful control of potential difficulties, and we summarise some important considerations and potential confounders. Our recommendations include the quantification and standardisation of contraction intensity, and how best to account for heterogeneous muscle recruitment. We highlight some pitfalls in the assessment of mitochondrial function by analysis of phosphocreatine (PCr) recovery kinetics. Finally, we outline how complementary techniques (near-infrared spectroscopy, arterial spin labelling, BOLD and various other MRI and 1 H MRS measurements) can help in the physiological/metabolic interpretation of 31 P MRS studies by providing information about blood flow and oxygen delivery/utilisation. Our recommendations will assist in achieving the fullest possible reliable picture of muscle physiology and pathophysiology.
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Affiliation(s)
- Martin Meyerspeer
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
- High Field MR CenterMedical University of ViennaViennaAustria
| | - Chris Boesch
- DBMR and DIPRUniversity and InselspitalBernSwitzerland
| | - Donnie Cameron
- Norwich Medical SchoolUniversity of East AngliaNorwichUK
- C. J. Gorter Center for High Field MRI, Department of RadiologyLeiden University Medical CentreLeidenthe Netherlands
| | - Monika Dezortová
- MR‐Unit, Department of Diagnostic and Interventional RadiologyInstitute for Clinical and Experimental MedicinePragueCzech Republic
| | - Sean C. Forbes
- Department of Physical TherapyUniversity of FloridaGainesvilleFloridaUSA
| | - Arend Heerschap
- Department of Radiology and Nuclear MedicineRadboud University Medical CenterNijmegenThe Netherlands
| | - Jeroen A.L. Jeneson
- Department of RadiologyAmsterdam University Medical Center|site AMCAmsterdamthe Netherlands
- Cognitive Neuroscience CenterUniversity Medical Center GroningenGroningenthe Netherlands
- Center for Child Development and Exercise, Wilhelmina Children's HospitalUniversity Medical Center UtrechtUtrechtthe Netherlands
| | - Hermien E. Kan
- C. J. Gorter Center for High Field MRI, Department of RadiologyLeiden University Medical CentreLeidenthe Netherlands
- Duchenne CenterThe Netherlands
| | - Jane Kent
- Department of KinesiologyUniversity of Massachusetts AmherstMAUSA
| | - Gwenaël Layec
- Department of KinesiologyUniversity of Massachusetts AmherstMAUSA
- Institute for Applied Life SciencesUniversity of MassachusettsAmherstMAUSA
| | | | - Harmen Reyngoudt
- NMR Laboratory, Neuromuscular Investigation CenterInstitute of Myology AIM‐CEAParisFrance
| | - Alison Sleigh
- Wolfson Brain Imaging CentreUniversity of CambridgeCambridgeUK
- Wellcome Trust‐MRC Institute of Metabolic ScienceUniversity of CambridgeCambridgeUK
- NIHR/Wellcome Trust Clinical Research FacilityCambridge University Hospitals NHS Foundation TrustCambridgeUK
| | - Ladislav Valkovič
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), RDM Cardiovascular Medicine, BHF Centre of Research ExcellenceUniversity of OxfordOxfordUK
- Department of Imaging MethodsInstitute of Measurement Science, Slovak Academy of SciencesBratislavaSlovakia
| | - Graham J. Kemp
- Department of Musculoskeletal Biology and Liverpool Magnetic Resonance Imaging Centre (LiMRIC)University of LiverpoolLiverpoolUK
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12
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In vivo assessment of muscle mitochondrial function in healthy, young males in relation to parameters of aerobic fitness. Eur J Appl Physiol 2019; 119:1799-1808. [PMID: 31177324 PMCID: PMC6647177 DOI: 10.1007/s00421-019-04169-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 05/28/2019] [Indexed: 11/17/2022]
Abstract
Purpose The recovery of muscle oxygen consumption (m\documentclass[12pt]{minimal}
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\begin{document}$$\dot{V}$$\end{document}V˙O2) after exercise provides a measure of skeletal muscle mitochondrial capacity, as more and better-functioning mitochondria will be able to restore m\documentclass[12pt]{minimal}
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\begin{document}$$\dot{V}$$\end{document}V˙O2 faster to the pre-exercise state. The aim was to measure muscle mitochondrial capacity using near-infrared spectroscopy (NIRS) within a healthy, normally active population and relate this to parameters of aerobic fitness, investigating the applicability and relevance of using NIRS to assess muscle mitochondrial capacity non-invasively. Methods Mitochondrial capacity was analysed in the gastrocnemius and flexor digitorum superficialis (FDS) muscles of eight relatively high-aerobic fitness (\documentclass[12pt]{minimal}
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\begin{document}$$\dot{V}$$\end{document}V˙O2peak ≥ 57 mL/kg/min) and eight relatively low-aerobic fitness male subjects (\documentclass[12pt]{minimal}
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\begin{document}$$\dot{V}$$\end{document}V˙O2peak ≤ 47 mL/kg/min). Recovery of whole body \documentclass[12pt]{minimal}
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\begin{document}$$\dot{V}$$\end{document}V˙O2, i.e. excess post-exercise oxygen consumption (EPOC) was analysed after a cycling protocol. Results Mitochondrial capacity, as analysed using NIRS, was significantly higher in high-fitness individuals compared to low-fitness individuals in the gastrocnemius, but not in the FDS (p = 0.0036 and p = 0.20, respectively). Mitochondrial capacity in the gastrocnemius was significantly correlated with \documentclass[12pt]{minimal}
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\begin{document}$$\dot{V}$$\end{document}V˙O2peak (R2 = 0.57, p = 0.0019). Whole body \documentclass[12pt]{minimal}
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\begin{document}$$\dot{V}$$\end{document}V˙O2 recovery was significantly faster in the high-fitness individuals (p = 0.0048), and correlated significantly with mitochondrial capacity in the gastrocnemius (R2 = 0.34, p = 0.028). Conclusion NIRS measurements can be used to assess differences in mitochondrial muscle oxygen consumption within a relatively normal, healthy population. Furthermore, mitochondrial capacity correlated with parameters of aerobic fitness (\documentclass[12pt]{minimal}
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\begin{document}$$\dot{V}$$\end{document}V˙O2peak and EPOC), emphasising the physiological relevance of the NIRS measurements.
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13
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Cree-Green M, Scalzo RL, Harrall K, Newcomer BR, Schauer IE, Huebschmann AG, McMillin S, Brown MS, Orlicky D, Knaub L, Nadeau KJ, McClatchey PM, Bauer TA, Regensteiner JG, Reusch JEB. Supplemental Oxygen Improves In Vivo Mitochondrial Oxidative Phosphorylation Flux in Sedentary Obese Adults With Type 2 Diabetes. Diabetes 2018; 67:1369-1379. [PMID: 29643061 PMCID: PMC6463751 DOI: 10.2337/db17-1124] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 03/29/2018] [Indexed: 12/11/2022]
Abstract
Type 2 diabetes is associated with impaired exercise capacity. Alterations in both muscle perfusion and mitochondrial function can contribute to exercise impairment. We hypothesized that impaired muscle mitochondrial function in type 2 diabetes is mediated, in part, by decreased tissue oxygen delivery and would improve with oxygen supplementation. Ex vivo muscle mitochondrial content and respiration assessed from biopsy samples demonstrated expected differences in obese individuals with (n = 18) and without (n = 17) diabetes. Similarly, in vivo mitochondrial oxidative phosphorylation capacity measured in the gastrocnemius muscle via 31P-MRS indicated an impairment in the rate of ADP depletion with rest (27 ± 6 s [diabetes], 21 ± 7 s [control subjects]; P = 0.008) and oxidative phosphorylation (P = 0.046) in type 2 diabetes after isometric calf exercise compared with control subjects. Importantly, the in vivo impairment in oxidative capacity resolved with oxygen supplementation in adults with diabetes (ADP depletion rate 5.0 s faster, P = 0.012; oxidative phosphorylation 0.046 ± 0.079 mmol/L/s faster, P = 0.027). Multiple in vivo mitochondrial measures related to HbA1c These data suggest that oxygen availability is rate limiting for in vivo mitochondrial oxidative exercise recovery measured with 31P-MRS in individuals with uncomplicated diabetes. Targeting muscle oxygenation could improve exercise function in type 2 diabetes.
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Affiliation(s)
- Melanie Cree-Green
- Center for Women's Health Research, Anschutz Medical Campus, Aurora, CO
- Division of Pediatric Endocrinology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Rebecca L Scalzo
- Center for Women's Health Research, Anschutz Medical Campus, Aurora, CO
- Division of Endocrinology and Metabolism, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Kylie Harrall
- Center for Women's Health Research, Anschutz Medical Campus, Aurora, CO
- School of Pharmacy, University of Colorado Anschutz Medical Campus, Aurora, CO
| | | | - Irene E Schauer
- Center for Women's Health Research, Anschutz Medical Campus, Aurora, CO
- Division of Endocrinology and Metabolism, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
- Veterans Affairs Medical Center, Denver, CO
| | - Amy G Huebschmann
- Center for Women's Health Research, Anschutz Medical Campus, Aurora, CO
- Division of General Internal Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Shawna McMillin
- Division of General Internal Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Mark S Brown
- Department of Radiology, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - David Orlicky
- Division of Pathology, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Leslie Knaub
- Division of Endocrinology and Metabolism, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Kristen J Nadeau
- Center for Women's Health Research, Anschutz Medical Campus, Aurora, CO
- Division of Pediatric Endocrinology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - P Mason McClatchey
- Division of Endocrinology and Metabolism, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Timothy A Bauer
- Division of General Internal Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Judith G Regensteiner
- Center for Women's Health Research, Anschutz Medical Campus, Aurora, CO
- Division of General Internal Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
- Division of Cardiology, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Jane E B Reusch
- Center for Women's Health Research, Anschutz Medical Campus, Aurora, CO
- Veterans Affairs Medical Center, Denver, CO
- Division of General Internal Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
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14
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Bashir A, Bohnert KL, Reeds DN, Peterson LR, Bittel AJ, de Las Fuentes L, Pacak CA, Byrne BJ, Cade WT. Impaired cardiac and skeletal muscle bioenergetics in children, adolescents, and young adults with Barth syndrome. Physiol Rep 2018; 5:5/3/e13130. [PMID: 28196853 PMCID: PMC5309577 DOI: 10.14814/phy2.13130] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 12/19/2016] [Accepted: 12/22/2016] [Indexed: 11/24/2022] Open
Abstract
Barth syndrome (BTHS) is an X‐linked condition characterized by altered cardiolipin metabolism and cardioskeletal myopathy. We sought to compare cardiac and skeletal muscle bioenergetics in children, adolescents, and young adults with BTHS and unaffected controls and examine their relationships with cardiac function and exercise capacity. Children/adolescents and young adults with BTHS (n = 20) and children/adolescent and young adult control participants (n = 23, total n = 43) underwent 31P magnetic resonance spectroscopy (31P‐MRS) of the lower extremity (calf) and heart for estimation of skeletal muscle and cardiac bioenergetics. Peak exercise testing (VO2peak) and resting echocardiography were also performed on all participants. Cardiac PCr/ATP ratio was significantly lower in children/adolescents (BTHS: 1.5 ± 0.2 vs. Control: 2.0 ± 0.3, P < 0.01) and adults (BTHS: 1.9 ± 0.2 vs. Control: 2.3 ± 0.2, P < 0.01) with BTHS compared to Control groups. Adults (BTHS: 76.4 ± 31.6 vs. Control: 35.0 ± 7.4 sec, P < 0.01) and children/adolescents (BTHS: 71.5 ± 21.3 vs. Control: 31.4 ± 7.4 sec, P < 0.01) with BTHS had significantly longer calf PCr recovery (τPCr) postexercise compared to controls. Maximal calf ATP production through oxidative phosphorylation (Qmax‐lin) was significantly lower in children/adolescents (BTHS: 0.5 ± 0.1 vs. Control: 1.1 ± 0.3 mmol/L per sec, P < 0.01) and adults (BTHS: 0.5 ± 0.2 vs. Control: 1.0 ± 0.2 mmol/L sec, P < 0.01) with BTHS compared to controls. Blunted cardiac and skeletal muscle bioenergetics were associated with lower VO2peak but not resting cardiac function. Cardiac and skeletal muscle bioenergetics are impaired and appear to contribute to exercise intolerance in BTHS.
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Affiliation(s)
- Adil Bashir
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri.,Department of Electrical and Computer Engineering, Auburn University, Auburn, Alabama
| | - Kathryn L Bohnert
- Program in Physical Therapy, Washington University School of Medicine, St. Louis, Missouri
| | - Dominic N Reeds
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri
| | - Linda R Peterson
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri
| | - Adam J Bittel
- Program in Physical Therapy, Washington University School of Medicine, St. Louis, Missouri
| | - Lisa de Las Fuentes
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri
| | - Christina A Pacak
- Department of Pediatrics, University of Florida, Gainesville, Florida
| | - Barry J Byrne
- Department of Pediatrics, University of Florida, Gainesville, Florida
| | - W Todd Cade
- Program in Physical Therapy, Washington University School of Medicine, St. Louis, Missouri .,Department of Medicine, Washington University School of Medicine, St. Louis, Missouri
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15
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Cree-Green M, Xie D, Rahat H, Garcia-Reyes Y, Bergman BC, Scherzinger A, Diniz Behn C, Chan CL, Kelsey MM, Pyle L, Nadeau KJ. Oral Glucose Tolerance Test Glucose Peak Time Is Most Predictive of Prediabetes and Hepatic Steatosis in Obese Girls. J Endocr Soc 2018. [PMID: 29942919 DOI: 10.1210/js.2018‐00041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Obese adolescent girls are at increased risk for type 2 diabetes, characterized by defects in insulin secretion and action. We sought to determine if later glucose peak timing (>30 minutes), 1-hour glucose >155 mg/dl, or monophasic pattern of glucose excursion during an oral glucose tolerance test (OGTT) reflect a worse cardiometabolic risk profile. Post-pubertal overweight/obese adolescent girls without diabetes were studied (N = 88; age, 15.2 ± 0.2 years; body mass index percentile, 97.7 ± 0.5). All participants completed an OGTT and body composition measures. Thirty-two girls had a four-phase hyperinsulinemic euglycemic clamp with isotope tracers, vascular imaging, and muscle mitochondrial assessments. Participants were categorized by glucose peak timing (≤30 min = early; >30 min = late), 1-hour glucose concentration (±155 mg/dL) and glucose pattern (monophasic, biphasic). Girls with a late (N = 54) vs earlier peak (n = 34) timing had higher peak glucose (P < 0.001) and insulin (P = 0.023), HbA1c (P = 0.021); prevalence of hepatic steatosis (62% vs 26%; P = 0.003) and lower oral disposition index (P < 0.001) and glucagon-like peptide-1 response (P = 0.037). When classified by 1-hour glucose, group differences were similar to peak timing, but minimal when classified by glucose pattern. In the >155 mg/dL group only, peripheral insulin sensitivity and fasting free fatty acids were worse. A later glucose peak or >155 mg/dL 1-hour glucose predicts metabolic disease risk in obese adolescent girls. This may defect incretin effects and first phase insulin response, and muscle and adipose insulin resistance.
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Affiliation(s)
- Melanie Cree-Green
- Division of Pediatric Endocrinology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado.,Center for Women's Health Research, Aurora, Colorado
| | - Danielle Xie
- Division of Pediatric Endocrinology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Haseeb Rahat
- Division of Pediatric Endocrinology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Yesenia Garcia-Reyes
- Division of Pediatric Endocrinology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Bryan C Bergman
- Division of Endocrinology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Ann Scherzinger
- Department of Radiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Cecilia Diniz Behn
- Division of Pediatric Endocrinology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado.,Department of Applied Mathematics and Statistics, Colorado School of Mines, Golden, Colorado
| | - Christine L Chan
- Division of Pediatric Endocrinology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Megan M Kelsey
- Division of Pediatric Endocrinology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado.,Center for Women's Health Research, Aurora, Colorado
| | - Laura Pyle
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado.,Department of Biostatistics and Informatics, Colorado School of Public Health, Aurora, Colorado
| | - Kristen J Nadeau
- Division of Pediatric Endocrinology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado.,Center for Women's Health Research, Aurora, Colorado
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16
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Cree-Green M, Xie D, Rahat H, Garcia-Reyes Y, Bergman BC, Scherzinger A, Diniz Behn C, Chan CL, Kelsey MM, Pyle L, Nadeau KJ. Oral Glucose Tolerance Test Glucose Peak Time Is Most Predictive of Prediabetes and Hepatic Steatosis in Obese Girls. J Endocr Soc 2018; 2:547-562. [PMID: 29942919 PMCID: PMC6007246 DOI: 10.1210/js.2018-00041] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 05/02/2018] [Indexed: 02/06/2023] Open
Abstract
Obese adolescent girls are at increased risk for type 2 diabetes, characterized by defects in insulin secretion and action. We sought to determine if later glucose peak timing (>30 minutes), 1-hour glucose >155 mg/dl, or monophasic pattern of glucose excursion during an oral glucose tolerance test (OGTT) reflect a worse cardiometabolic risk profile. Post-pubertal overweight/obese adolescent girls without diabetes were studied (N = 88; age, 15.2 ± 0.2 years; body mass index percentile, 97.7 ± 0.5). All participants completed an OGTT and body composition measures. Thirty-two girls had a four-phase hyperinsulinemic euglycemic clamp with isotope tracers, vascular imaging, and muscle mitochondrial assessments. Participants were categorized by glucose peak timing (≤30 min = early; >30 min = late), 1-hour glucose concentration (±155 mg/dL) and glucose pattern (monophasic, biphasic). Girls with a late (N = 54) vs earlier peak (n = 34) timing had higher peak glucose (P < 0.001) and insulin (P = 0.023), HbA1c (P = 0.021); prevalence of hepatic steatosis (62% vs 26%; P = 0.003) and lower oral disposition index (P < 0.001) and glucagon-like peptide-1 response (P = 0.037). When classified by 1-hour glucose, group differences were similar to peak timing, but minimal when classified by glucose pattern. In the >155 mg/dL group only, peripheral insulin sensitivity and fasting free fatty acids were worse. A later glucose peak or >155 mg/dL 1-hour glucose predicts metabolic disease risk in obese adolescent girls. This may defect incretin effects and first phase insulin response, and muscle and adipose insulin resistance.
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Affiliation(s)
- Melanie Cree-Green
- Division of Pediatric Endocrinology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado.,Center for Women's Health Research, Aurora, Colorado
| | - Danielle Xie
- Division of Pediatric Endocrinology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Haseeb Rahat
- Division of Pediatric Endocrinology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Yesenia Garcia-Reyes
- Division of Pediatric Endocrinology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Bryan C Bergman
- Division of Endocrinology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Ann Scherzinger
- Department of Radiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Cecilia Diniz Behn
- Division of Pediatric Endocrinology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado.,Department of Applied Mathematics and Statistics, Colorado School of Mines, Golden, Colorado
| | - Christine L Chan
- Division of Pediatric Endocrinology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Megan M Kelsey
- Division of Pediatric Endocrinology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado.,Center for Women's Health Research, Aurora, Colorado
| | - Laura Pyle
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado.,Department of Biostatistics and Informatics, Colorado School of Public Health, Aurora, Colorado
| | - Kristen J Nadeau
- Division of Pediatric Endocrinology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado.,Center for Women's Health Research, Aurora, Colorado
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17
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van Diemen MP, Berends CL, Akram N, Wezel J, Teeuwisse WM, Mik BG, Kan HE, Webb A, Beenakker JWM, Groeneveld GJ. Validation of a pharmacological model for mitochondrial dysfunction in healthy subjects using simvastatin: A randomized placebo-controlled proof-of-pharmacology study. Eur J Pharmacol 2017; 815:290-297. [DOI: 10.1016/j.ejphar.2017.09.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 09/16/2017] [Accepted: 09/20/2017] [Indexed: 10/18/2022]
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18
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Cree-Green M, Cai N, Pyle L, Ringham B, Brown MS, Newcomer BR, Nadeau KJ, Dabelea D. Insulin Resistance in Youth Without Diabetes Is Not Related to Muscle Mitochondrial Dysfunction. J Clin Endocrinol Metab 2017; 102:1652-1660. [PMID: 28204552 PMCID: PMC5443327 DOI: 10.1210/jc.2016-3912] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 02/03/2017] [Indexed: 12/19/2022]
Abstract
Context Obesity, insulin resistance (IR), and diabetes are increasing in youth, especially in girls. IR is associated with muscle mitochondrial dysfunction in youth and adults with diabetes. However, it is unknown whether this relationship is present in youth prior to development of diabetes. Objective Assess IR and mitochondrial function, including sex differences, in nondiabetic youth. Design Cross-sectional study of youth in the Exploring Perinatal Outcomes among Children, Resistance to InSulin in Type 1 And Type 2 diabetes, and Androgens and Insulin Resistance Study cohorts. Setting Academic medical university. Participants Two hundred seventy-five youth, 13 to 19 years old [43% males: 17.1 (16.52, 17.63) years, body mass index z-score (BMI-Z) 0.36, 64.7% Tanner 5; 57% females: 17.2 (16.43, 17.67) years, BMI-Z 0.72, 78.9% Tanner 5]. Interventions Fasting laboratories, oral glucose tolerance test, and 31P magnetic resonance spectroscopy. Main Outcome Measures IR [triglyceride:high-density lipoprotein (HDL) ratio, Matsuda index, and homeostasis model for insulin resistance (HOMA-IR)] and muscle mitochondrial function (adenosine 5'-diphosphate time constant and oxidative phosphorylation rate). Results Compared with males, females were more insulin resistant, with higher triglyceride:HDL ratio [1.95 (1.30, 2.79) vs 1.69 (1.21, 2.23), P = 0.042], HOMA-IR [3.18 (2.42, 4.39) vs 2.76 (2.02, 4.08), P = 0.035], and fasting free fatty acids (FFAs) and lower Matsuda score [3.98 (2.71, 5.96) vs 5.39 (3.43, 7.57), P < 0.001]. After adjustment for the higher BMI and Tanner stage and lower physical activity levels seen in females, there were no sex differences in mitochondrial function nor in any IR measure except FFAs. We did not find an association between measures of IR and mitochondrial function. Conclusions The greater IR seen in adolescent girls vs boys is mostly explained by differences in BMI and physical activity. Mitochondrial function does not appear to be related to IR in a large cohort of nondiabetic youth.
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Affiliation(s)
- Melanie Cree-Green
- Pediatric Endocrinology, University of Colorado Anschutz and Children’s Hospital Colorado, Aurora, Colorado 80045
| | - Ninghe Cai
- Pediatric Endocrinology, University of Colorado Anschutz and Children’s Hospital Colorado, Aurora, Colorado 80045
| | - Laura Pyle
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado 80045
- Department of Biostatistics and Informatics, Colorado School of Public Health, Aurora, Colorado 80045
| | - Brandy Ringham
- Department of Epidemiology, Colorado School of Public Health, Aurora, Colorado 80045
| | - Mark S. Brown
- Radiology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, Colorado 80045
| | - Bradley R. Newcomer
- Department of Physics, James Madison University, Harrisonburg, Virginia 22807
| | - Kristen J. Nadeau
- Pediatric Endocrinology, University of Colorado Anschutz and Children’s Hospital Colorado, Aurora, Colorado 80045
| | - Dana Dabelea
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado 80045
- Department of Epidemiology, Colorado School of Public Health, Aurora, Colorado 80045
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Kumar V, Chang H, Reiter DA, Bradley DP, Belury M, McCormack SE, Raman SV. Phosphorus-31 Magnetic Resonance Spectroscopy: A Tool for Measuring In Vivo Mitochondrial Oxidative Phosphorylation Capacity in Human Skeletal Muscle. J Vis Exp 2017. [PMID: 28190054 DOI: 10.3791/54977] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Skeletal muscle mitochondrial oxidative phosphorylation (OXPHOS) capacity, which is critically important in health and disease, can be measured in vivo and noninvasively in humans via phosphorus-31 magnetic resonance spectroscopy (31PMRS). However, the approach has not been widely adopted in translational and clinical research, with variations in methodology and limited guidance from the literature. Increased optimization, standardization, and dissemination of methods for in vivo 31PMRS would facilitate the development of targeted therapies to improve OXPHOS capacity and could ultimately favorably impact cardiovascular health. 31PMRS produces a noninvasive, in vivo measure of OXPHOS capacity in human skeletal muscle, as opposed to alternative measures obtained from explanted and potentially altered mitochondria via muscle biopsy. It relies upon only modest additional instrumentation beyond what is already in place on magnetic resonance scanners available for clinical and translational research at most institutions. In this work, we outline a method to measure in vivo skeletal muscle OXPHOS. The technique is demonstrated using a 1.5 Tesla whole-body MR scanner equipped with the suitable hardware and software for 31PMRS, and we explain a simple and robust protocol for in-magnet resistive exercise to rapidly fatigue the quadriceps muscle. Reproducibility and feasibility are demonstrated in volunteers as well as subjects over a wide range of functional capacities.
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Affiliation(s)
- Vidhya Kumar
- Davis Heart and Lung Research Institute, The Ohio State University
| | - Henry Chang
- Davis Heart and Lung Research Institute, The Ohio State University
| | - David A Reiter
- Laboratory of Clinical Investigation, National Institute on Aging
| | - David P Bradley
- Division of Endocrinology, Diabetes and Metabolism, The Ohio State University
| | - Martha Belury
- Department of Human Sciences, Human Nutrition, The Ohio State University
| | - Shana E McCormack
- Division of Endocrinology and Diabetes, Department of Pediatrics, University of Pennsylvania
| | - Subha V Raman
- Davis Heart and Lung Research Institute, The Ohio State University;
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20
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A low-cost Mr compatible ergometer to assess post-exercise phosphocreatine recovery kinetics. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2017; 30:281-289. [PMID: 28054143 DOI: 10.1007/s10334-016-0605-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 12/15/2016] [Accepted: 12/19/2016] [Indexed: 01/16/2023]
Abstract
OBJECTIVE To develop a low-cost pedal ergometer compatible with ultrahigh (7 T) field MR systems to reliably quantify metabolic parameters in human lower leg muscle using phosphorus magnetic resonance spectroscopy. MATERIALS AND METHODS We constructed an MR compatible ergometer using commercially available materials and elastic bands that provide resistance to movement. We recruited ten healthy subjects (eight men and two women, mean age ± standard deviation: 32.8 ± 6.0 years, BMI: 24.1 ± 3.9 kg/m2). All subjects were scanned on a 7 T whole-body magnet. Each subject was scanned on two visits and performed a 90 s plantar flexion exercise at 40% maximum voluntary contraction during each scan. During the first visit, each subject performed the exercise twice in order for us to estimate the intra-exam repeatability, and once during the second visit in order to estimate the inter-exam repeatability of the time constant of phosphocreatine recovery kinetics. We assessed the intra and inter-exam reliability in terms of the within-subject coefficient of variation (CV). RESULTS We acquired reliable measurements of PCr recovery kinetics with an intra- and inter-exam CV of 7.9% and 5.7%, respectively. CONCLUSION We constructed a low-cost pedal ergometer compatible with ultrahigh (7 T) field MR systems, which allowed us to quantify reliably PCr recovery kinetics in lower leg muscle using 31P-MRS.
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21
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Cree-Green M, Gupta A, Coe GV, Baumgartner AD, Pyle L, Reusch JEB, Brown MS, Newcomer BR, Nadeau KJ. Insulin resistance in type 2 diabetes youth relates to serum free fatty acids and muscle mitochondrial dysfunction. J Diabetes Complications 2017; 31:141-148. [PMID: 27839922 PMCID: PMC5395421 DOI: 10.1016/j.jdiacomp.2016.10.014] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 09/14/2016] [Accepted: 10/10/2016] [Indexed: 12/15/2022]
Abstract
AIMS Insulin resistance (IR) correlates with mitochondrial dysfunction, free fatty acids (FFAs), and intramyocellular lipid (IMCL) in adults with type 2 diabetes (T2D). We hypothesized that muscle IR would relate to similar factors in T2D youth. METHODS Participants included 17 youth with T2D, 23 normal weight controls (LCs), and 26 obese controls (OBs) of similar pubertal stage and activity level. RESULTS T2D and OB groups were of similar BMI. T2D youth were significantly more IR and had higher calf IMCL and serum FFA concentrations during hyperinsulinemia. ADP time constant (ADPTC), a blood-flow dependent mitochondrial function measure, was slowed and oxidative phosphorylation rates lower in T2D. In multiple linear regression of the entire cohort, lack of FFA suppression and longer ADPTC, but not IMCL or HbA1c, were independently associated with IR. CONCLUSION We found that elevated FFAs and mitochondrial dysfunction are early abnormalities in relatively well-controlled youth with T2D. Further, post-exercise oxidative metabolism appears affected by reduced blood flow, and is not solely an inherent mitochondrial defect. Thus, lowering FFAs and improving mitochondrial function and blood flow may be potential treatment targets in youth with T2D.
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Affiliation(s)
- Melanie Cree-Green
- Division of Pediatric Endocrinology, University of Colorado Anschutz Medical Campus and Children's Hospital Colorado, Aurora, CO, 80045; Center for Women's Health Research, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045.
| | - Abhinav Gupta
- Division of Pediatric Endocrinology, University of Colorado Anschutz Medical Campus and Children's Hospital Colorado, Aurora, CO, 80045
| | - Gregory V Coe
- Division of Pediatric Endocrinology, University of Colorado Anschutz Medical Campus and Children's Hospital Colorado, Aurora, CO, 80045
| | - Amy D Baumgartner
- Division of Pediatric Endocrinology, University of Colorado Anschutz Medical Campus and Children's Hospital Colorado, Aurora, CO, 80045
| | - Laura Pyle
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045; Department of Biostatistics and Informatics, Colorado School of Public Health, Aurora, CO, 80045
| | - Jane E B Reusch
- Center for Women's Health Research, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045; Division of Endocrinology, Metabolism and Diabetes, University to Colorado Anschutz Medical Campus, Aurora, CO, 80045; Veterans Affairs Medical Center, Aurora, CO, 80012
| | - Mark S Brown
- Department of Radiology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045
| | | | - Kristen J Nadeau
- Division of Pediatric Endocrinology, University of Colorado Anschutz Medical Campus and Children's Hospital Colorado, Aurora, CO, 80045; Center for Women's Health Research, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045
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22
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Fitzgerald LF, Christie AD, Kent JA. Heterogeneous effects of old age on human muscle oxidative capacity in vivo: a systematic review and meta-analysis. Appl Physiol Nutr Metab 2016; 41:1137-1145. [DOI: 10.1139/apnm-2016-0195] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Despite intensive efforts to understand the extent to which skeletal muscle mitochondrial capacity changes in older humans, the answer to this important question remains unclear. To determine what the preponderance of evidence from in vivo studies suggests, we conducted a systematic review and meta-analysis of the effects of age on muscle oxidative capacity as measured noninvasively by magnetic resonance spectroscopy. A secondary aim was to examine potential moderators contributing to differences in results across studies, including muscle group, physical activity status, and sex. Candidate papers were identified from PubMed searches (n = 3561 papers) and the reference lists of relevant papers. Standardized effects (Hedges’ g) were calculated for age and each moderator using data from the 22 studies that met the inclusion criteria (n = 28 effects). Effects were coded as positive when older (age, ≥55 years) adults had higher muscle oxidative capacity than younger (age, 20–45 years) adults. The overall effect of age on oxidative capacity was positive (g = 0.171, p < 0.001), indicating modestly greater oxidative capacity in old. Notably, there was significant heterogeneity in this result (Q = 245.8, p < 0.001; I2 = ∼70%–90%). Muscle group, physical activity, and sex were all significant moderators of oxidative capacity (p ≤ 0.029). This analysis indicates that the current body of literature does not support a de facto decrease of in vivo muscle oxidative capacity in old age. The heterogeneity of study results and identification of significant moderators provide clarity regarding apparent discrepancies in the literature, and indicate the importance of accounting for these variables when examining purported age-related differences in muscle oxidative capacity.
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Affiliation(s)
- Liam F. Fitzgerald
- Department of Kinesiology, University of Massachusetts Amherst, MA 01003, USA
| | - Anita D. Christie
- Department of Human Physiology, University of Oregon, Eugene, OR 97403, USA
| | - Jane A. Kent
- Department of Kinesiology, University of Massachusetts Amherst, MA 01003, USA
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23
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Simple and effective exercise design for assessing in vivo mitochondrial function in clinical applications using (31)P magnetic resonance spectroscopy. Sci Rep 2016; 6:19057. [PMID: 26751849 PMCID: PMC4707472 DOI: 10.1038/srep19057] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 12/02/2015] [Indexed: 02/02/2023] Open
Abstract
The growing recognition of diseases associated with dysfunction of mitochondria poses an urgent need for simple measures of mitochondrial function. Assessment of the kinetics of replenishment of the phosphocreatine pool after exercise using (31)P magnetic resonance spectroscopy can provide an in vivo measure of mitochondrial function; however, the wider application of this technique appears limited by complex or expensive MR-compatible exercise equipment and protocols not easily tolerated by frail participants or those with reduced mental capacity. Here we describe a novel in-scanner exercise method which is patient-focused, inexpensive, remarkably simple and highly portable. The device exploits an MR-compatible high-density material (BaSO4) to form a weight which is attached directly to the ankle, and a one-minute dynamic knee extension protocol produced highly reproducible measurements of post-exercise PCr recovery kinetics in both healthy subjects and patients. As sophisticated exercise equipment is unnecessary for this measurement, our extremely simple design provides an effective and easy-to-implement apparatus that is readily translatable across sites. Its design, being tailored to the needs of the patient, makes it particularly well suited to clinical applications, and we argue the potential of this method for investigating in vivo mitochondrial function in new cohorts of growing clinical interest.
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24
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Cree-Green M, Newcomer BR, Brown M, Hull A, West AD, Singel D, Reusch JEB, McFann K, Regensteiner JG, Nadeau KJ. Method for controlled mitochondrial perturbation during phosphorus MRS in children. Med Sci Sports Exerc 2015; 46:2030-6. [PMID: 24576856 DOI: 10.1249/mss.0000000000000316] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
UNLABELLED Insulin resistance is increasingly prevalent in children and may be related to muscle mitochondrial dysfunction, necessitating development of mitochondrial assessment techniques. Recent studies used phosphorus magnetic resonance spectroscopy (P-MRS), a noninvasive technique appealing for clinical research. P-MRS requires exercise at a precise percentage of maximum volitional contraction (MVC). MVC measurement in children, particularly in those with a disease, is problematic because of variability in perception of effort and motivation. We therefore developed a method to predict MVC using maximal calf muscle cross-sectional area (MCSA) to assure controlled and reproducible muscle metabolic perturbations. METHODS Data were collected from 66 sedentary 12- to 20-yr-old participants. Plantarflexion MVC was assessed using an MRI-compatible exercise treadle device. MCSA of the calf muscles were measured from magnetic resonance images. Data from the first 26 participants were used to model the relation between MVC and MCSA (predicted MVC = 24.763 + 0.0047 MCSA). This model was then applied to the subsequent 40 participants. RESULTS MVC versus model-predicted mean MVC was 43.9 ± 0.8 kg versus 44.2 ± 1.81 (P = 0.90). P-MRS results when predicted and MVC were similar showed expected changes during MVC-based exercise. In contrast, MVC was markedly lower than predicted in four participants and produced minimal metabolic perturbation. Upon repeat testing, these individuals could perform their predicted MVC with coaching, which produced expected metabolic perturbations. CONCLUSIONS Compared with using MVC testing alone, using magnetic resonance imaging to predict muscle strength allows for a more accurate and standardized P-MRS protocol during exercise in children. This method overcomes a major obstacle in assessing mitochondrial function in youths. These studies have importance as we seek to determine the role of mitochondrial function in youths with insulin resistance and diabetes and response to interventions.
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Affiliation(s)
- Melanie Cree-Green
- 1Division of Endocrinology, Department of Pediatrics, Children's Hospital Colorado, Anschutz Medical Campus, Aurora, CO; 2Center for Women's Health Research, University of Colorado Anschutz Medical Campus, Aurora, CO; 3Department of Clinical and Diagnostic Sciences, University of Alabama at Birmingham, Birmingham, AL; 4Department of Radiology, University of Colorado Anschutz Medical Campus, Aurora, CO; and 5Department of Internal Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
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25
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Cree-Green M, Newcomer BR, Coe G, Newnes L, Baumgartner A, Brown MS, Pyle L, Reusch JE, Nadeau KJ. Peripheral insulin resistance in obese girls with hyperandrogenism is related to oxidative phosphorylation and elevated serum free fatty acids. Am J Physiol Endocrinol Metab 2015; 308:E726-33. [PMID: 25714677 PMCID: PMC4420897 DOI: 10.1152/ajpendo.00619.2014] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Accepted: 02/19/2015] [Indexed: 12/25/2022]
Abstract
Hyperandrogenic syndrome (HAS) is associated with insulin resistance (IR) and type 2 diabetes. Muscle IR in type 2 diabetes is linked with defects in mitochondrial oxidative capacity. In vivo muscle mitochondrial function has not been studied in HAS, especially in youth, who are early in the disease process. Our goal was to measure muscle mitochondrial oxidative function and peripheral IR in obese youth with HAS. Obese girls without HAS [n = 22, age 15(13,17) yr, BMI Z-score 2.05 ± 0.37] and with HAS [n = 35, age 15(14,16) yr, BMI Z-score 2.18 ± 0.30] were enrolled. Mitochondrial function was assessed with (31)phosphorus MR spectroscopy before, during, and after near-maximal isometric calf exercise, and peripheral IR was assessed with an 80 mU·m(-2)·min(-1) hyperinsulinemic euglycemic clamp. Girls with HAS had higher androgens [free androgen index 7.9(6.6,15.5) vs. 3.5(3.0,4.0), P < 0.01] and more IR [glucose infusion rate 9.4(7.0, 12,2) vs. 14.5(13.2,15.8) mg·kg lean(-1)·min(-1), P < 0.01]. HAS girls also had increased markers of inflammation including CRP, platelets, and white blood cell count and higher serum free fatty acids during hyperinsulinemia. Mitochondrial oxidative phosphorylation was lower in HAS [0.11(0.06,0.19) vs. 0.18(0.12,0.23) mmol/s, P < 0.05], although other spectroscopy markers of mitochondrial function were similar between groups. In multivariate analysis of the entire cohort, IR related to androgens, oxidative phosphorylation, and free fatty acid concentrations during hyperinsulinemia. These relationships were present in just the HAS cohort as well. Obese girls with HAS have significant peripheral IR, which is related to elevated androgens and free fatty acids and decreased mitochondrial oxidative phosphorylation. These may provide future options as targets for therapeutic intervention.
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Affiliation(s)
- Melanie Cree-Green
- Division of Endocrinology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado; Center for Women's Health Research, Anschutz Medical Campus, Aurora, Colorado;
| | - Bradley R Newcomer
- Department of Clinical and Diagnostic Sciences, University of Alabama at Birmingham, Birmingham, Alabama
| | - Gregory Coe
- Division of Endocrinology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Lindsey Newnes
- Division of Endocrinology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Amy Baumgartner
- Division of Endocrinology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Mark S Brown
- Department of Radiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Laura Pyle
- Department of Pediatrics, University of Colorado School of Medicine, and Department of Biostatistics and Informatics, Colorado School of Public Health, Aurora, Colorado
| | - Jane E Reusch
- Division of Endocrinology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado; and Department of Veteran Affairs, Denver, Colorado
| | - Kristen J Nadeau
- Division of Endocrinology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado; Center for Women's Health Research, Anschutz Medical Campus, Aurora, Colorado
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26
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Cree-Green M, Newcomer BR, Brown MS, Baumgartner AD, Bergman B, Drew B, Regensteiner JG, Pyle L, Reusch JEB, Nadeau KJ. Delayed skeletal muscle mitochondrial ADP recovery in youth with type 1 diabetes relates to muscle insulin resistance. Diabetes 2015; 64:383-92. [PMID: 25157095 PMCID: PMC4303961 DOI: 10.2337/db14-0765] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Insulin resistance (IR) increases cardiovascular morbidity and is associated with mitochondrial dysfunction. IR is now recognized to be present in type 1 diabetes; however, its relationship with mitochondrial function is unknown. We determined the relationship between IR and muscle mitochondrial function in type 1 diabetes using the hyperinsulinemic-euglycemic clamp and (31)P-MRS before, during, and after near-maximal isometric calf exercise. Volunteers included 21 nonobese adolescents with type 1 diabetes and 17 nondiabetic control subjects with similar age, sex, BMI, Tanner stage, and activity levels. We found that youths with type 1 diabetes were more insulin resistant (median glucose infusion rate 10.1 vs. 18.9 mg/kglean/min; P < 0.0001) and had a longer time constant of the curve of ADP conversion to ATP (23.4 ± 5.3 vs. 18.8 ± 3.9 s, P < 0.001) and a lower rate of oxidative phosphorylation (median 0.09 vs. 0.21 mmol/L/s, P < 0.001). The ADP time constant (β = -0.36, P = 0.026) and oxidative phosphorylation (β = 0.02, P < 0.038) were related to IR but not HbA1c. Normal-weight youths with type 1 diabetes demonstrated slowed postexercise ATP resynthesis and were more insulin resistant than control subjects. The correlation between skeletal muscle mitochondrial dysfunction in type 1 diabetes and IR suggests a relationship between mitochondrial dysfunction and IR in type 1 diabetes.
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Affiliation(s)
- Melanie Cree-Green
- Division of Endocrinology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO Center for Women's Health Research, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Bradley R Newcomer
- Department of Clinical and Diagnostic Sciences, University of Alabama at Birmingham, Birmingham, AL
| | - Mark S Brown
- Department of Radiology, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Amy D Baumgartner
- Division of Endocrinology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Bryan Bergman
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO Division of Endocrinology and Metabolism, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Brendan Drew
- Division of Endocrinology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Judith G Regensteiner
- Center for Women's Health Research, University of Colorado Anschutz Medical Campus, Aurora, CO Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO Divisions of General Internal Medicine and Cardiology, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Laura Pyle
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Jane E B Reusch
- Center for Women's Health Research, University of Colorado Anschutz Medical Campus, Aurora, CO Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO Division of Endocrinology and Metabolism, University of Colorado Anschutz Medical Campus, Aurora, CO Veterans Affairs Medical Center, Denver, CO
| | - Kristen J Nadeau
- Division of Endocrinology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO Center for Women's Health Research, University of Colorado Anschutz Medical Campus, Aurora, CO
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27
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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: 99] [Impact Index Per Article: 11.0] [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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28
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Southern WM, Ryan TE, Reynolds MA, McCully K. Reproducibility of near-infrared spectroscopy measurements of oxidative function and postexercise recovery kinetics in the medial gastrocnemius muscle. Appl Physiol Nutr Metab 2014; 39:521-9. [DOI: 10.1139/apnm-2013-0347] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The purpose of this study was to assess the reproducibility of resting blood flow, resting oxygen consumption, and mitochondrial capacity in skeletal muscle using near-infrared spectroscopy (NIRS). We also determined the influence of 2 exercise modalities (ergometer and rubber exercise bands) on the NIRS measurements. Fifteen young, healthy participants (5 female, 10 male) were tested on 2 nonconsecutive occasions within an 8-day period. The NIRS device was placed on the medial gastrocnemius. Venous and arterial occlusions were performed to obtain blood flow and oxygen consumption. A series of repeated arterial occlusions was used to measure the recovery kinetics of muscle oxygen consumption after ∼7–10 s of voluntary plantar flexion exercise. Resting blood flow had mean coefficients of variation (CV) of 42% and 38% for bands and ergometer, respectively, and resting metabolism had mean CVs of 17% and 12% for bands and ergometer, respectively. The recovery time constant of oxygen consumption (day 1 bands and ergometer: 23.2 ± 3.7 s, 27.6 ± 6.5 s, respectively; day 2 bands and ergometer: 25.5 ± 5.4 s, 25.0 ± 4.9 s, respectively) had mean CVs of 10% and 11% for bands and ergometer, respectively. We conclude that measurements of oxygen consumption and mitochondrial capacity using NIRS can be obtained with good reproducibility.
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Affiliation(s)
- William M. Southern
- Department of Kinesiology, University of Georgia, 330 River Rd., Athens, GA 30602, USA
| | - Terence E. Ryan
- Department of Kinesiology, University of Georgia, 330 River Rd., Athens, GA 30602, USA
| | - Mary A. Reynolds
- Department of Kinesiology, University of Georgia, 330 River Rd., Athens, GA 30602, USA
| | - Kevin McCully
- Department of Kinesiology, University of Georgia, 330 River Rd., Athens, GA 30602, USA
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29
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Prompers JJ, Wessels B, Kemp GJ, Nicolay K. MITOCHONDRIA: investigation of in vivo muscle mitochondrial function by 31P magnetic resonance spectroscopy. Int J Biochem Cell Biol 2014; 50:67-72. [PMID: 24569118 DOI: 10.1016/j.biocel.2014.02.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Revised: 02/06/2014] [Accepted: 02/16/2014] [Indexed: 01/06/2023]
Abstract
The most important function of mitochondria is the production of energy in the form of ATP. The socio-economic impact of human diseases that affect skeletal muscle mitochondrial function is growing, and improving their clinical management critically depends on the development of non-invasive assays to assess mitochondrial function and monitor the effects of interventions. 31P magnetic resonance spectroscopy provides two approaches that have been used to assess in vivo ATP synthesis in skeletal muscle: measuring Pi→ATP exchange flux using saturation transfer in resting muscle, and measuring phosphocreatine recovery kinetics after exercise. However, Pi→ATP exchange does not represent net mitochondrial ATP synthesis flux and has no simple relationship with mitochondrial function. Post-exercise phosphocreatine recovery kinetics, on the other hand, yield reliable measures of muscle mitochondrial capacity in vivo, whose ability to define the site of functional defects is enhanced by combination with other non-invasive techniques.
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Affiliation(s)
- Jeanine J Prompers
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.
| | - Bart Wessels
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Graham J Kemp
- Department of Musculoskeletal Biology and Magnetic Resonance & Image Analysis Research Centre, University of Liverpool, UK
| | - Klaas Nicolay
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
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30
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Abstract
A growing body of research is investigating the potential contribution of mitochondrial function to the etiology of type 2 diabetes. Numerous in vitro, in situ, and in vivo methodologies are available to examine various aspects of mitochondrial function, each requiring an understanding of their principles, advantages, and limitations. This review provides investigators with a critical overview of the strengths, limitations and critical experimental parameters to consider when selecting and conducting studies on mitochondrial function. In vitro (isolated mitochondria) and in situ (permeabilized cells/tissue) approaches provide direct access to the mitochondria, allowing for study of mitochondrial bioenergetics and redox function under defined substrate conditions. Several experimental parameters must be tightly controlled, including assay media, temperature, oxygen concentration, and in the case of permeabilized skeletal muscle, the contractile state of the fibers. Recently developed technology now offers the opportunity to measure oxygen consumption in intact cultured cells. Magnetic resonance spectroscopy provides the most direct way of assessing mitochondrial function in vivo with interpretations based on specific modeling approaches. The continuing rapid evolution of these technologies offers new and exciting opportunities for deciphering the potential role of mitochondrial function in the etiology and treatment of diabetes.
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Affiliation(s)
- Christopher G R Perry
- School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada.
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31
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Edwards LM, Kemp GJ, Dwyer RM, Walls JT, Fuller H, Smith SR, Earnest CP. Integrating muscle cell biochemistry and whole-body physiology in humans:(31)P-MRS data from the InSight trial. Sci Rep 2013; 3:1182. [PMID: 23378914 PMCID: PMC3560356 DOI: 10.1038/srep01182] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Accepted: 09/24/2012] [Indexed: 01/04/2023] Open
Abstract
We acquired 31P-MRS data from skeletal muscle of subjects of mixed gender and ethnicity, combined with a panel of physiological characteristics, and tested several long-standing hypotheses regarding relationships between muscle cell biochemistry and whole-body physiology with unusually high statistical power. We hypothesized that i) whole-body VO2max would correlate with muscle respiratory capacity, ii) resting muscle phosphocreatine concentration ([PCr]) would negatively correlate with delta efficiency and iii) muscle mitochondrial function would positively correlate with both resting VO2 and total daily energy expenditure (TDEE). Muscle respiratory capacity explained a quarter of the variation in VO2max (r2 = 26, p < .001, n = 87). There was an inverse correlation between muscle [PCr] and delta efficiency (r = −23, p = 046, n = 87). There was also a correlation between [PCr] recovery halftime and TDEE (r = −23, p = 035, n = 87). Our data not only provide insights into muscle cell chemistry and whole-body physiology but our mixed cohort means that our findings are broadly generalizable.
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Libri V, Brown AP, Gambarota G, Haddad J, Shields GS, Dawes H, Pinato DJ, Hoffman E, Elliot PJ, Vlasuk GP, Jacobson E, Wilkins MR, Matthews PM. A pilot randomized, placebo controlled, double blind phase I trial of the novel SIRT1 activator SRT2104 in elderly volunteers. PLoS One 2012; 7:e51395. [PMID: 23284689 PMCID: PMC3527451 DOI: 10.1371/journal.pone.0051395] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2012] [Accepted: 10/31/2012] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND SRT2104 has been developed as a selective small molecule activator of SIRT1, a NAD(+)-dependent deacetylase involved in the regulation of energy homeostasis and the modulation of various metabolic pathways, including glucose metabolism, oxidative stress and lipid metabolism. SIRT1 has been suggested as putative therapeutic target in multiple age-related diseases including type 2 diabetes and dyslipidemias. We report the first clinical trial of SRT2104 in elderly volunteers. METHODS Oral doses of 0.5 or 2.0 g SRT2104 or matching placebo were administered once daily for 28 days. Pharmacokinetic samples were collected through 24 hours post-dose on days 1 and 28. Multiple pharmacodynamic endpoints were explored with oral glucose tolerance tests (OGTT), serum lipid profiles, magnetic resonance imaging (MRI) for assessment of whole body visceral and subcutaneous fat, maximal aerobic capacity test and muscle 31P magnetic resonance spectroscopy (MRS) for estimation of mitochondrial oxidative capacity. RESULTS SRT2104 was generally safe and well tolerated. Pharmacokinetic exposure increased less than dose-proportionally. Mean Tmax was 2-4 hours with elimination half-life of 15-20 hours. Serum cholesterol, LDL levels and triglycerides decreased with treatment. No significant changes in OGTT responses were observed. 31P MRS showed trends for more rapid calculated adenosine diphosphate (ADP) and phosphocreatine (PCr) recoveries after exercise, consistent with increased mitochondrial oxidative phosphorylation. CONCLUSIONS SRT2104 can be safely administered in elderly individuals and has biological effects in humans that are consistent with SIRT1 activation. The results of this study support further development of SRT2104 and may be useful in dose selection for future clinical trials in patients. TRIAL REGISTRATION ClinicalTrials.gov NCT00964340.
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Affiliation(s)
- Vincenzo Libri
- The National Institute for Health Research-Wellcome Trust Imperial College Clinical Research Facility, Imperial Centre for Translational and Experimental Medicine, Imperial College London, United Kingdom.
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Edwards LM, Tyler DJ, Kemp GJ, Dwyer RM, Johnson A, Holloway CJ, Nevill AM, Clarke K. The reproducibility of 31-phosphorus MRS measures of muscle energetics at 3 Tesla in trained men. PLoS One 2012; 7:e37237. [PMID: 22701564 PMCID: PMC3372482 DOI: 10.1371/journal.pone.0037237] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Accepted: 04/18/2012] [Indexed: 01/21/2023] Open
Abstract
Objective Magnetic resonance spectroscopy (MRS) provides an exceptional opportunity for the study of in vivo metabolism. MRS is widely used to measure phosphorus metabolites in trained muscle, although there are no published data regarding its reproducibility in this specialized cohort. Thus, the aim of this study was to assess the reproducibility of 31P-MRS in trained skeletal muscle. Methods We recruited fifteen trained men (VO2peak = 4.7±0.8 L min−1/58±8 mL kg−1 min−1) and performed duplicate MR experiments during plantar flexion exercise, three weeks apart. Results Measures of resting phosphorus metabolites were reproducible, with 1.7 mM the smallest detectable difference in phosphocreatine (PCr). Measures of metabolites during exercise were less reliable: exercising PCr had a coefficient of variation (CV) of 27% during exercise, compared with 8% at rest. Estimates of mitochondrial function were variable, but experimentally useful. The CV of PCr1/2t was 40%, yet much of this variance was inter-subject such that differences of <20% were detectable with n = 15, given a significance threshold of p<0.05. Conclusions 31-phosphorus MRS provides reproducible and experimentally useful measures of phosphorus metabolites and mitochondrial function in trained human skeletal muscle.
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Affiliation(s)
- Lindsay M Edwards
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom.
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Lanza IR, Bhagra S, Nair KS, Port JD. Measurement of human skeletal muscle oxidative capacity by 31P-MR spectroscopy: a cross-validation with in vitro measurements. J Magn Reson Imaging 2012; 34:1143-50. [PMID: 22006551 DOI: 10.1002/jmri.22733] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
PURPOSE To cross-validate skeletal muscle oxidative capacity measured by (31)P-MR spectroscopy with in vitro measurements of oxidative capacity in mitochondria isolated from muscle biopsies of the same muscle group in 18 healthy adults. MATERIALS AND METHODS Oxidative capacity in vivo was determined from PCr recovery kinetics following a 30-s maximal isometric knee extension. State 3 respiration was measured in isolated mitochondria using high-resolution respirometry. A second cohort of 10 individuals underwent two (31)P-MRS testing sessions to assess the test-retest reproducibility of the method. RESULTS Overall, the in vivo and in vitro methods were well-correlated (r = 0.66-0.72) and showed good agreement by Bland Altman plots. Excellent reproducibility was observed for the PCr recovery rate constant (CV = 4.6%; ICC = 0.85) and calculated oxidative capacity (CV = 3.4%; ICC = 0.83). CONCLUSION These results indicate that (31)P-MRS corresponds well with gold-standard in vitro measurements and is highly reproducible.
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Affiliation(s)
- Ian R Lanza
- Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA
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Bhella PS, Prasad A, Heinicke K, Hastings JL, Arbab-Zadeh A, Adams-Huet B, Pacini EL, Shibata S, Palmer MD, Newcomer BR, Levine BD. Abnormal haemodynamic response to exercise in heart failure with preserved ejection fraction. Eur J Heart Fail 2011; 13:1296-304. [PMID: 21979991 DOI: 10.1093/eurjhf/hfr133] [Citation(s) in RCA: 180] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
AIMS Peak oxygen uptake (VO(2)) is diminished in patients with heart failure with preserved ejection fraction (HFpEF) suggesting impaired cardiac reserve. To test this hypothesis, we assessed the haemodynamic response to exercise in HFpEF patients. METHODS AND RESULTS Eleven HFpEF patients (73 ± 7 years, 7 females/4 males) and 13 healthy controls (70 ± 4 years, 6 females/7 males) were studied during submaximal and maximal exercise. The cardiac output (Q(c), acetylene rebreathing) response to exercise was determined from linear regression of Q(c) and VO(2) (Douglas bags) at rest, ∼30% and ∼60% of peak VO(2), and maximal exercise. Peak VO(2) was lower in HFpEF patients than in controls (13.7 ± 3.4 vs. 21.6 ± 3.6 mL/kg/min; P < 0.001), while indices of cardiac reserve were not statistically different: peak cardiac power output [CPO = Q(c) × mean arterial pressure (MAP); HFpEF 1790 ± 509 vs. controls 2119 ± 581 L/mmHg/min; P = 0.20]; peak stroke work [SW = stroke volume (SV) × MAP; HFpEF 13 429 ± 2269 vs. controls 13 200 ± 3610 mL/mmHg; P = 0.80]. The ΔQ(c)/ΔVO(2) slope was abnormally elevated in HFpEF patients vs. controls (11.2 ±3.6 vs. 8.3 ± 1.5; P = 0.015). CONCLUSION Contrary to our hypothesis, cardiac reserve is not significantly impaired in well-compensated outpatients with HFpEF. The abnormal haemodynamic response to exercise (decreased peak VO(2), increased ΔQ(c)/ΔVO(2) slope) is similar to that observed in patients with mitochondrial myopathies, suggesting an element of impaired skeletal muscle oxidative metabolism. This impairment may limit functional capacity by two mechanisms: (i) premature skeletal muscle fatigue and (ii) metabolic signals to increase the cardiac output response to exercise which may be poorly tolerated by a left ventricle with impaired diastolic function.
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Affiliation(s)
- Paul S Bhella
- The Institute for Exercise and Environmental Medicine, 7232 Greenville Avenue, Dallas, TX 75231, USA
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Andreas M, Schmid AI, Keilani M, Doberer D, Bartko J, Crevenna R, Moser E, Wolzt M. Effect of ischemic preconditioning in skeletal muscle measured by functional magnetic resonance imaging and spectroscopy: a randomized crossover trial. J Cardiovasc Magn Reson 2011; 13:32. [PMID: 21718491 PMCID: PMC3143996 DOI: 10.1186/1532-429x-13-32] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Accepted: 06/30/2011] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Nuclear magnetic resonance (NMR) imaging and spectroscopy have been applied to assess skeletal muscle oxidative metabolism. Therefore, in-vivo NMR may enable the characterization of ischemia-reperfusion injury. The goal of this study was to evaluate whether NMR could detect the effects of ischemic preconditioning (IPC) in healthy subjects. METHODS Twenty-three participants were included in two randomized crossover protocols in which the effects of IPC were measured by NMR and muscle force assessments. Leg ischemia was administered for 20 minutes with or without a subsequent impaired reperfusion for 5 minutes (stenosis model). IPC was administered 4 or 48 hours prior to ischemia. Changes in 31phosphate NMR spectroscopy and blood oxygen level-dependent (BOLD) signals were recorded. 3-Tesla NMR data were compared to those obtained for isometric muscular strength. RESULTS The phosphocreatine (PCr) signal decreased robustly during ischemia and recovered rapidly during reperfusion. In contrast to PCr, the recovery of muscular strength was slow. During post-ischemic stenosis, PCr increased only slightly. The BOLD signal intensity decreased during ischemia, ischemic exercise and post-ischemic stenosis but increased during hyperemic reperfusion. IPC 4 hours prior to ischemia significantly increased the maximal PCr reperfusion signal and mitigated the peak BOLD signal during reperfusion. CONCLUSIONS Ischemic preconditioning positively influenced muscle metabolism during reperfusion; this resulted in an increase in PCr production and higher oxygen consumption, thereby mitigating the peak BOLD signal. In addition, an impairment of energy replenishment during the low-flow reperfusion was detected in this model. Thus, functional NMR is capable of characterizing changes in reperfusion and in therapeutic interventions in vivo. TRIAL REGISTRATION ClinicalTrials.gov: NCT00883467.
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Affiliation(s)
- Martin Andreas
- Department of Clinical Pharmacology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
| | - Albrecht I Schmid
- Department of Clinical Pharmacology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
- MR Center of Excellence, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
| | - Mohammad Keilani
- Department of Physical Medicine and Rehabilitation, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
| | - Daniel Doberer
- Department of Clinical Pharmacology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
| | - Johann Bartko
- Department of Clinical Pharmacology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
| | - Richard Crevenna
- Department of Physical Medicine and Rehabilitation, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
| | - Ewald Moser
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
- MR Center of Excellence, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
| | - Michael Wolzt
- Department of Clinical Pharmacology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
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Affiliation(s)
- Douglas E. Befroy
- Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
- Corresponding author: Douglas E. Befroy, , or Gerald I. Shulman,
| | - Gerald I. Shulman
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut
- Corresponding author: Douglas E. Befroy, , or Gerald I. Shulman,
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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: 35] [Impact Index Per Article: 2.7] [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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Exercise economy in African American and European American women. Eur J Appl Physiol 2011; 111:1863-9. [PMID: 21229260 DOI: 10.1007/s00421-010-1816-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Accepted: 12/24/2010] [Indexed: 10/18/2022]
Abstract
We have previously shown that Achilles tendon length is related to walking economy on the flat, presumably because of increased stretch-shortening cycle elastic energy savings. In addition, greater walking economy in African American (AA) women compared to European American (EA) women is explained by longer Achilles tendons in AA women. The purposes of this study were to determine whether economy while walking up a grade and during isometric plantar flexion, two tasks expected to produce proportionately less energy savings from elastic savings are different between AA and EA women. We evaluated walking economy at 4.8 km/h at 0 and 2.5% grade in 48 AA and 48 EA premenopausal women. Plantar flexor muscle metabolic economy (force/ATP) was also evaluated using (31) phosphate magnetic resonance spectroscopy ((31)P-MRS). AA women walked on the flat more economically (net VO(2), AA 8.3 and EA 8.9 ml kg(-1) min(-1), P = 0.04). No significant ethnic differences were observed while walking up a 2.5% grade or in (31)P-MRS determined plantar flexor muscle metabolic economy. These data support our previous study's suggestion that AA women are more economical while walking on the flat. On the other hand, in activities in which stretch-shortening cycle elastic energy savings would be expected to be reduced (grade walking and isometric force production), no differences in economy during grade walking or isometric force production were observed suggesting that biomechanical, i.e. stretch-shortening cycle elastic energy savings differences rather biochemical differences contribute to the better flat walking economy observed in AA women.
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Hunter GR, Bickel CS, Del Corral P, Byrne NM, Hills AP, Larson-Meyer DE, Bamman MM, Newcomer BR. Age, muscle fatigue, and walking endurance in pre-menopausal women. Eur J Appl Physiol 2010; 111:715-23. [PMID: 20972575 DOI: 10.1007/s00421-010-1694-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/07/2010] [Indexed: 12/01/2022]
Abstract
Aging is associated with loss of endurance; however, aging is also associated with decreased fatigue during maximal isometric contractions. The aims of this study were to examine the relationship between age and walking endurance (WE) and maximal isometric fatigue (MIF) and to determine which metabolic/fitness components explain the expected age effects on WE and MIF. Subjects were 96 pre-menopausal women. Oxygen uptake (walking economy) was assessed during a 3-mph walk; aerobic capacity and WE by progressive treadmill test; knee extension strength by isometric contractions, MIF during a 90-s isometric plantar flexion (muscle metabolism measured by (31)P MRS). Age was related to increased walking economy (low VO(2), r = -0.19, P < 0.03) and muscle metabolic economy (force/ATP, 0.34, P = 0.01), and reduced MIF (-0.26, P < 0.03). However, age was associated with reduced WE (-0.28, P < 0.01). Multiple regression showed that muscle metabolic economy explained the age-related decrease in MIF (partial r for MIF and age -0.13, P = 0.35) whereas walking economy did not explain the age-related decrease in WE (partial r for WE and age -0.25, P < 0.02). Inclusion of VO(2max) and knee endurance strength accounted for the age-related decreased WE (partial r for WE and age = 0.03, P > 0.80). In premenopausal women, age is related to WE and MIF. In addition, these results support the hypothesis that age-related increases in metabolic economy may decrease MIF. However, decreased muscle strength and oxidative capacity are related to WE.
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Affiliation(s)
- Gary R Hunter
- Department of Human Studies, University of Alabama at Birmingham, 901 South 13th Street, Birmingham, AL 35294-1250, USA.
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Fleischman A, Makimura H, Stanley TL, McCarthy MA, Kron M, Sun N, Chuzi S, Hrovat MI, Systrom DM, Grinspoon SK. Skeletal muscle phosphocreatine recovery after submaximal exercise in children and young and middle-aged adults. J Clin Endocrinol Metab 2010; 95:E69-74. [PMID: 20554709 PMCID: PMC2936068 DOI: 10.1210/jc.2010-0527] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
CONTEXT Elderly subjects have reduced mitochondrial function. However, it remains unclear whether the decline in mitochondrial function begins earlier in the life span. OBJECTIVE The objective of the study was to determine skeletal muscle mitochondrial oxidative phosphorylation by (31)phosphorous-magnetic resonance spectroscopy (MRS) across a variety of age groups. DESIGN This was a cross-sectional study of 121 healthy normal-weight and overweight individuals from age 8 to 55 yr. SETTING The study was conducted at a single university medical center in Boston, MA. PARTICIPANTS Participants included 68 children and 53 adults from the Boston community. INTERVENTIONS AND MAIN OUTCOME MEASURES Phosphocreatine (PCr) recovery was evaluated by (31)phosphorous-MRS after submaximal exercise. Subjects were also evaluated with anthropometric measurements, metabolic profiles, and measures of physical activity. RESULTS PCr recovery determined by (31)phosphorous-MRS is positively associated with age in univariate analysis in a cohort of individuals aged 8-55 yr (r = +0.55, P < 0.0001). Stratification of subjects into four age groups (prepubertal and early pubertal children, pubertal and postpubertal children < 18 yr, young adults aged 18-39 yr, and middle aged adults aged 40-55 yr) demonstrates prolongation of PCr recovery with increasing age across the four groups (P < 0.0001 by ANOVA). The relationship between PCr recovery and age remains strong when controlling for gender; race; ethnicity; body mass index; measures of physical activity and inactivity; and anthropometric, nutritional, and metabolic parameters (P < 0.004). CONCLUSIONS Skeletal muscle PCr recovery measured by (31)phosphorous-MRS is prolonged with age, even in children and young adults.
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Affiliation(s)
- Amy Fleischman
- Program in Nutritional Metabolism and Neuroendocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA
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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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McCully KK, Turner TN, Langley J, Zhao Q. The reproducibility of measurements of intramuscular magnesium concentrations and muscle oxidative capacity using 31P MRS. DYNAMIC MEDICINE : DM 2009; 8:5. [PMID: 20003509 PMCID: PMC2801477 DOI: 10.1186/1476-5918-8-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2009] [Accepted: 12/15/2009] [Indexed: 11/29/2022]
Abstract
31P magnetic resonance spectroscopy (31P MRS) has been used to measure intramuscular magnesium concentrations and muscle metabolism. Abnormal intramuscular magnesium has been reported in several patient populations with suspected metabolic disorders. The purpose of this study was to evaluate our ability to measure intramuscular magnesium and muscle metabolism in the quadriceps muscles of healthy subjects, and to test whether these measurements were influenced by prior exercise. Twelve normal, healthy male volunteers were tested in a 3 Tesla magnet on four separate days. Resting [Mg2+] was calculated from the heights and frequency shifts of the phosphate, phosphocreatine and ATP peaks. Phosphocreatine (PCr) recovery kinetics were measured after 30-39 second bouts of isometric exercise. Thirty minutes prior to the 3rd test session the subjects completed a 2 hour treadmill walk at 40-60% of heart rate reserve. Resting [Mg2+] averaged 0.388 mM and had an interclass correlation coefficient between days (ICC) of 0.352. The mean end exercise PCr was 47.6% and the mean end exercise pH was 6.97. PCr recovery averaged 39 seconds (p = 0.892) and had an ICC of 0.819. Prior long duration exercise did not produce significant alterations in either PCr recovery kinetics or intracellular magnesium levels (p = 0.440). In conclusion, the reproducibility of Resting [Mg2+] was less than that of PCr recovery measurements, and may reflect the sensitivity of these measurements to phasing errors. In addition, prior exercise is unlikely to alter measurements of resting metabolites or muscle metabolism suggesting that rigorous control of physical activity prior to metabolic testing is unnecessary.
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Affiliation(s)
- Kevin K McCully
- Department of Kinesiology, University of Georgia, Athens, GA, USA
| | - Tiffany N Turner
- Department of Kinesiology, University of Georgia, Athens, GA, USA
| | - Jason Langley
- Department of Physics and Astronomy & BioImaging Research Center, University of Georgia, Athens, GA, USA
| | - Qun Zhao
- Department of Physics and Astronomy & BioImaging Research Center, University of Georgia, Athens, GA, USA
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Shaibi GQ, Faulkner MS, Weigensberg MJ, Fritschi C, Goran MI. Cardiorespiratory fitness and physical activity in youth with type 2 diabetes. Pediatr Diabetes 2008; 9:460-3. [PMID: 18503498 PMCID: PMC2562936 DOI: 10.1111/j.1399-5448.2008.00407.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
OBJECTIVE The increased incidence of type 2 diabetes (T2D) among youth is hypothesized to be due, in part, to low levels of fitness and activity. Therefore, the purpose of this investigation was to examine whether cardiorespiratory fitness and physical activity are reduced in youth with T2D compared with overweight controls. PARTICIPANTS Thirteen adolescent boys with previously diagnosed T2D (mean duration 2.4 +/- 1.8 yr) were matched for age and body mass index to 13 overweight, non-diabetic controls. METHODS Cardiorespiratory fitness was assessed during a progressive exercise test to volitional fatigue and physical activity was estimated from a 7-d physical activity recall. RESULTS Youth with T2D reported performing approximately 60% less moderate to vigorous physical activity compared with their non-diabetic counterparts (0.6 +/- 0.2 vs. 1.4 +/- 0.3 h/d, p = 0.04). Furthermore, diabetic youth exhibited significantly lower cardiorespiratory fitness levels compared with controls (28.7 +/- 1.6 vs. 34.6 +/- 2.2 mL/kg/min, p < 0.05). CONCLUSIONS These findings support the hypothesis that cardiorespiratory fitness and physical activity are reduced in youth with T2D. Whether reduced fitness and activity contributed to the pathophysiology of the disorder cannot be determined from the cross-sectional analysis. Longitudinal studies are warranted to examine whether improvements in fitness and increased physical activity can prevent the development of T2D in high-risk youth.
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Affiliation(s)
- Gabriel Q. Shaibi
- College of Nursing & Healthcare Innovation, Arizona State University, Phoenix, AZ, 85004
| | | | - Marc J. Weigensberg
- Department of Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033
| | - Cynthia Fritschi
- Department of Medical-Surgical Nursing, University of Illinois at Chicago, Chicago, IL, 60612
| | - Michael I. Goran
- Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033,Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033
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Sirikul B, Hunter GR, Larson-Meyer DE, Desmond R, Newcomer BR. Relationship between metabolic function and skeletal muscle fatigue during a 90 s maximal isometric contraction. Appl Physiol Nutr Metab 2007; 32:394-9. [PMID: 17510673 DOI: 10.1139/h06-117] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Little is known concerning the contributions of oxidative phosphorylation (OxPhos), anaerobic glycolytic rate (AnGly), maximum creatine kinase (CK) activity, and metabolic economy (ME) on fatigue resistance. The purpose of this study was to model fatigue using muscle tissue metabolic measures during a maximal short-duration isometric contraction. Muscle metabolic function was measured with [31P]-magnetic resonance spectroscopy (MRS) in 54 premenopausal women (age: 33.8+/-6.3 y) while they performed 100% isometric plantar flexions. Multiple regression analysis revealed that all metabolic variables were independent predictors of fatigue resistance after adjusting for maximum isometric force generated (R2=0.56). ME accounted for the largest portion (36%) of overall shared variance. OxPhos accounted for the most shared variance of the three energy systems. These results support previous findings that OxPhos, AnGly, CK, and ME all contribute to fatigue resistance over a short duration. Additionally, the continued activity of CK at the end of 90 s of maximal exercise lends support to the concept of a CK shuttle facilitating energy transfer within the mitochondria.
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Affiliation(s)
- Bovorn Sirikul
- Department of Kinesiology and Health Studies, Southeastern Louisiana University, Hammond, LA 70402, USA.
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Fleischman A, Johnsen S, Systrom DM, Hrovat M, Farrar CT, Frontera W, Fitch K, Thomas BJ, Torriani M, Côté HCF, Grinspoon SK. Effects of a nucleoside reverse transcriptase inhibitor, stavudine, on glucose disposal and mitochondrial function in muscle of healthy adults. Am J Physiol Endocrinol Metab 2007; 292:E1666-73. [PMID: 17284576 PMCID: PMC3206591 DOI: 10.1152/ajpendo.00550.2006] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mitochondrial dysfunction may contribute to the development of insulin resistance and type 2 diabetes. Nucleoside reverse transcriptase inhibitors (NRTIs), specifically stavudine, are known to alter mitochondrial function in human immunodeficiency virus (HIV)-infected individuals, but the effects of stavudine on glucose disposal and mitochondrial function in muscle have not been prospectively evaluated. In this study, we investigated short-term stavudine administration among healthy control subjects to determine effects on insulin sensitivity. A secondary aim was to determine the effects of stavudine on mitochondrial DNA (mtDNA) and function. Sixteen participants without personal or family history of diabetes were enrolled. Subjects were randomized to receive stavudine, 30-40 mg, twice a day, or placebo for 1 mo. Insulin sensitivity determined by glucose infusion rate during the hyperinsulinemic euglycemic clamp was significantly reduced after 1-mo exposure in the stavudine-treated subjects compared with placebo (-0.8 +/- 0.5 vs. +0.7 +/- 0.3 mg.kg(-1).min(-1), P = 0.04, stavudine vs. placebo). In addition, muscle biopsy specimens in the stavudine-treated group showed significant reduction in mtDNA/nuclear DNA (-52%, P = 0.005), with no change in placebo-treated subjects (+8%, P = 0.9). (31)P magnetic resonance spectroscopy (MRS) studies of mitochondrial function correlated with insulin sensitivity measures (r2 = 0.5, P = 0.008). These findings demonstrate that stavudine administration has potent effects on insulin sensitivity among healthy subjects. Further studies are necessary to determine whether changes in mtDNA resulting from stavudine contribute to effects on insulin sensitivity.
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Affiliation(s)
- Amy Fleischman
- Program In Nutritional Metabolism, Massachusetts General Hospital, 55 Fruit St., LON 207, Boston, MA 02114, USA
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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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Jeppesen TD, Quistorff B, Wibrand F, Vissing J. 31P-MRS of skeletal muscle is not a sensitive diagnostic test for mitochondrial myopathy. J Neurol 2007; 254:29-37. [PMID: 17278044 DOI: 10.1007/s00415-006-0229-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2005] [Accepted: 03/15/2006] [Indexed: 11/25/2022]
Abstract
Clinical phenotypes of persons with mitochondrial DNA (mtDNA) mutations vary considerably. Therefore, diagnosing mitochondrial myopathy (MM) patients can be challenging and warrants diagnostic guidelines. (31)phosphorous magnetic resonance spectroscopy ((31)P-MRS) have been included as a minor diagnostic criterion for MM but the diagnostic strength of this test has not been compared with that of other commonly used diagnostic procedures for MM. To investigate this, we studied seven patients with single, large-scale deletions-, nine with point mutations of mtDNA and 14 healthy subjects, who were investigated for the following: 1) (31)P-MRS of lower arm and leg muscles before and after exercise, 2) resting and peak-exercise induced increases of plasma lactate, 3) muscle morphology and -mitochondrial enzyme activity, 4) maximal oxygen uptake (VO(2max)), 5) venous oxygen desaturation during handgrip exercise and 6) a neurological examination. All MM patients had clinical symptoms of MM, > 2% ragged red fibers in muscle, and impaired oxygen desaturation during handgrip. Fourteen of 16 patients had impaired VO(2max), 10/16 had elevated resting plasma lactate, and 10/11 that were investigated had impaired citrate synthase-corrected complex I activity. Resting PCr/P(i) ratio and leg P(i) recovery were lower in MM patients vs. healthy subjects. PCr and ATP production after exercise were similar in patients and healthy subjects. Although the specificity for MM of some (31)P-MRS variables was as high as 100%, the sensitivity was low (0-63%) and the diagnostic strength of (31)P-MRS was inferior to the other diagnostic tests for MM. Thus, (31)P-MRS should not be a routine test for MM, but may be an important research tool.
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Affiliation(s)
- Tina Dysgaard Jeppesen
- Neuromuscular Research Unit, Section 7611, National University Hospital, Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark.
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Roy JLP, Hunter GR, Fernandez JR, McCarthy JP, Larson-Meyer DE, Blaudeau TE, Newcomer BR. Cardiovascular factors explain genetic background differences in VO2max. Am J Hum Biol 2006; 18:454-60. [PMID: 16788902 DOI: 10.1002/ajhb.20509] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The purpose of this study was to further explore factors that may be related to ethnic differences in the maximum rate at which an individual can consume oxygen (VO2max) between 20 African American (AA) and 30 European American (EA) sedentary women who were matched for body weight (kg) and fat-free mass (FFM). VO2max (l/min) was determined during a graded treadmill exercise test. Submaximal steady-state heart rate and submaximal VO2 were determined at a treadmill speed of 1.3 m/sec and a 2.5% grade. Hemoglobin (Hb) was determined by the cyanide method, muscle oxidative capacity by 31P magnetic resonance spectroscopy (ADP time constant), and FFM (kg) by dual-energy x-ray absorptiometry. Genetic classification was self-reported, and in a subset of the sample (N = 32), the determinants of ethnicity were measured by African genetic admixture. AA women had significantly reduced VO2max, Hb levels, and muscle oxidative capacity (longer ADP time constants, P < or = 0.05) than EA women. Submaximal oxygen pulse (O2Psubmax), ADP time constant, Hb, and ethnic background were all significantly related to VO2max (ml/kg/min and ml/kg FFM/min, all P < or = 0.01). By multiple regression modeling, Hb, O2Psubmax, muscle oxidative capacity, and ethnicity were found to explain 61% and 57% of the variance of VO2max in ml/kg/min and ml/kg FFM/min, respectively. Muscle oxidative capacity and O2Psubmax were both significantly and independently related to VO2max in all three models (P < or = 0.05), whereas Hb and ethnicity were not. These results suggest that mitochondrial muscle oxidative capacity and oxygen delivery capabilities, as determined by O2Psubmax, account for most if not all of the ethnic differences in VO2max.
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Affiliation(s)
- Jane L P Roy
- Department of Human Studies, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
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Prompers JJ, Jeneson JAL, Drost MR, Oomens CCW, Strijkers GJ, Nicolay K. Dynamic MRS and MRI of skeletal muscle function and biomechanics. NMR IN BIOMEDICINE 2006; 19:927-53. [PMID: 17075956 DOI: 10.1002/nbm.1095] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
MR is a powerful technique for studying the biomechanical and functional properties of skeletal muscle in vivo in health and disease. This review focuses on 31P, 1H and 13C MR spectroscopy for assessment of the dynamics of muscle metabolism and on dynamic 1H MRI methods for non-invasive measurement of the biomechanical and functional properties of skeletal muscle. The information thus obtained ranges from the microscopic level of the metabolism of the myocyte to the macroscopic level of the contractile function of muscle complexes. The MR technology presented plays a vital role in achieving a better understanding of many basic aspects of muscle function, including the regulation of mitochondrial activity and the intricate interplay between muscle fiber organization and contractile function. In addition, these tools are increasingly being employed to establish novel diagnostic procedures as well as to monitor the effects of therapeutic and lifestyle interventions for muscle disorders that have an increasing impact in modern society.
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Affiliation(s)
- Jeanine J Prompers
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, The Netherlands
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