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Roshanravan B, Liu SZ, Ali AS, Shankland EG, Goss C, Amory JK, Robertson HT, Marcinek DJ, Conley KE. In vivo mitochondrial ATP production is improved in older adult skeletal muscle after a single dose of elamipretide in a randomized trial. PLoS One 2021; 16:e0253849. [PMID: 34264994 PMCID: PMC8282018 DOI: 10.1371/journal.pone.0253849] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 03/03/2021] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Loss of mitochondrial function contributes to fatigue, exercise intolerance and muscle weakness, and is a key factor in the disability that develops with age and a wide variety of chronic disorders. Here, we describe the impact of a first-in-class cardiolipin-binding compound that is targeted to mitochondria and improves oxidative phosphorylation capacity (Elamipretide, ELAM) in a randomized, double-blind, placebo-controlled clinical trial. METHODS Non-invasive magnetic resonance and optical spectroscopy provided measures of mitochondrial capacity (ATPmax) with exercise and mitochondrial coupling (ATP supply per O2 uptake; P/O) at rest. The first dorsal interosseous (FDI) muscle was studied in 39 healthy older adult subjects (60 to 85 yrs of age; 46% female) who were enrolled based on the presence of poorly functioning mitochondria. We measured volitional fatigue resistance by force-time integral over repetitive muscle contractions. RESULTS A single ELAM dose elevated mitochondrial energetic capacity in vivo relative to placebo (ΔATPmax; P = 0.055, %ΔATPmax; P = 0.045) immediately after a 2-hour infusion. No difference was found on day 7 after treatment, which is consistent with the half-life of ELAM in human blood. No significant changes were found in resting muscle mitochondrial coupling. Despite the increase in ATPmax there was no significant effect of treatment on fatigue resistance in the FDI. CONCLUSIONS These results highlight that ELAM rapidly and reversibly elevates mitochondrial capacity after a single dose. This response represents the first demonstration of a pharmacological intervention that can reverse mitochondrial dysfunction in vivo immediately after treatment in aging human muscle.
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Affiliation(s)
- Baback Roshanravan
- Department of Medicine, Division of Nephrology, University of California Davis, Sacramento, California, United States of America
| | - Sophia Z. Liu
- Department of Radiology, University of Washington, Seattle, Washington, United States of America
| | - Amir S. Ali
- Department of Radiology, University of Washington, Seattle, Washington, United States of America
| | - Eric G. Shankland
- Department of Radiology, University of Washington, Seattle, Washington, United States of America
| | - Chessa Goss
- Institute of Translational Health Sciences, University of Washington, Seattle, Washington, United States of America
| | - John K. Amory
- Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - H. Thomas Robertson
- Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - David J. Marcinek
- Department of Radiology, University of Washington, Seattle, Washington, United States of America
- Department of Bioengineering, University of Washington, Seattle, Washington, United States of America
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, United States of America
- * E-mail:
| | - Kevin E. Conley
- Department of Radiology, University of Washington, Seattle, Washington, United States of America
- Department of Bioengineering, University of Washington, Seattle, Washington, United States of America
- Department of Physiology & Biophysics, University of Washington, Seattle, Washington, United States of America
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Liu SZ, Valencia AP, VanDoren MP, Shankland EG, Roshanravan B, Conley KE, Marcinek DJ. Astaxanthin supplementation enhances metabolic adaptation with aerobic training in the elderly. Physiol Rep 2021; 9:e14887. [PMID: 34110707 PMCID: PMC8191397 DOI: 10.14814/phy2.14887] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 04/23/2021] [Accepted: 05/05/2021] [Indexed: 01/16/2023] Open
Abstract
Endurance training (ET) is recommended for the elderly to improve metabolic health and aerobic capacity. However, ET-induced adaptations may be suboptimal due to oxidative stress and exaggerated inflammatory response to ET. The natural antioxidant and anti-inflammatory dietary supplement astaxanthin (AX) has been found to increase endurance performance among young athletes, but limited investigations have focused on the elderly. We tested a formulation of AX in combination with ET in healthy older adults (65-82 years) to determine if AX improves metabolic adaptations with ET, and if AX effects are sex-dependent. Forty-two subjects were randomized to either placebo (PL) or AX during 3 months of ET. Specific muscle endurance was measured in ankle dorsiflexors. Whole body exercise endurance and fat oxidation (FATox) was assessed with a graded exercise test (GXT) in conjunction with indirect calorimetry. Results: ET led to improved specific muscle endurance only in the AX group (Pre 353 ± 26 vs. Post 472 ± 41 contractions), and submaximal GXT duration improved in both groups (PL 40.8 ± 9.1% and AX 41.1 ± 6.3%). The increase in FATox at lower intensity after ET was greater in AX (PL 0.23 ± 0.15 g vs. AX 0.76 ± 0.18 g) and was associated with reduced carbohydrate oxidation and increased exercise efficiency in males but not in females.
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Affiliation(s)
- Sophia Z. Liu
- Department of RadiologyUniversity of WashingtonSeattleWAUSA
| | | | - Matt P. VanDoren
- Exercise Research CenterFred Hutchinson Cancer Research CenterSeattleWAUSA
| | | | - Baback Roshanravan
- Department of Internal Medicine, Division of NephrologyUniversity of California DavisSacramentoCAUSA
| | - Kevin E. Conley
- Department of RadiologyUniversity of WashingtonSeattleWAUSA
- Department of Physiology & BiophysicsUniversity of WashingtonSeattleWAUSA
- Department of BioengineeringUniversity of WashingtonSeattleWAUSA
| | - David J. Marcinek
- Department of RadiologyUniversity of WashingtonSeattleWAUSA
- Department of BioengineeringUniversity of WashingtonSeattleWAUSA
- Department of MedicineUniversity of WashingtonSeattleWAUSA
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Whitson JA, Bitto A, Zhang H, Sweetwyne MT, Coig R, Bhayana S, Shankland EG, Wang L, Bammler TK, Mills KF, Imai S, Conley KE, Marcinek DJ, Rabinovitch PS. SS-31 and NMN: Two paths to improve metabolism and function in aged hearts. Aging Cell 2020; 19:e13213. [PMID: 32779818 PMCID: PMC7576234 DOI: 10.1111/acel.13213] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 06/16/2020] [Accepted: 07/13/2020] [Indexed: 12/14/2022] Open
Abstract
The effects of two different mitochondrial-targeted drugs, SS-31 and NMN, were tested on Old mouse hearts. After treatment with the drugs, individually or Combined, heart function was examined by echocardiography. SS-31 partially reversed an age-related decline in diastolic function while NMN fully reversed an age-related deficiency in systolic function at a higher workload. Metabolomic analysis revealed that both NMN and the Combined treatment increased nicotinamide and 1-methylnicotinamide levels, indicating greater NAD+ turnover, but only the Combined treatment resulted in significantly greater steady-state NAD(H) levels. A novel magnetic resonance spectroscopy approach was used to assess how metabolite levels responded to changing cardiac workload. PCr/ATP decreased in response to increased workload in Old Control, but not Young, hearts, indicating an age-related decline in energetic capacity. Both drugs were able to normalize the PCr/ATP dynamics. SS-31 and NMN treatment also increased mitochondrial NAD(P)H production under the higher workload, while only NMN increased NAD+ in response to increased work. These measures did not shift in hearts given the Combined treatment, which may be owed to the enhanced NAD(H) levels in the resting state after this treatment. Overall, these results indicate that both drugs are effective at restoring different aspects of mitochondrial and heart health and that combining them results in a synergistic effect that rejuvenates Old hearts and best recapitulates the Young state.
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Affiliation(s)
- Jeremy A. Whitson
- Department of Laboratory Medicine and PathologyUniversity of WashingtonSeattleWashingtonUSA
| | - Alessandro Bitto
- Department of Laboratory Medicine and PathologyUniversity of WashingtonSeattleWashingtonUSA
| | - Huiliang Zhang
- Department of Laboratory Medicine and PathologyUniversity of WashingtonSeattleWashingtonUSA
| | - Mariya T. Sweetwyne
- Department of Laboratory Medicine and PathologyUniversity of WashingtonSeattleWashingtonUSA
| | - Rene Coig
- Department of Laboratory Medicine and PathologyUniversity of WashingtonSeattleWashingtonUSA
| | - Saakshi Bhayana
- Department of RadiologyUniversity of WashingtonSeattleWashingtonUSA
| | | | - Lu Wang
- Department of Environmental & Occupational Health SciencesUniversity of WashingtonSeattleWashingtonUSA
| | - Theo K. Bammler
- Department of Environmental & Occupational Health SciencesUniversity of WashingtonSeattleWashingtonUSA
| | - Kathryn F. Mills
- Department of Developmental BiologyWashington University School of MedicineSt. LouisMissouriUSA
| | - Shin‐Ichiro Imai
- Department of Developmental BiologyWashington University School of MedicineSt. LouisMissouriUSA
| | - Kevin E. Conley
- Department of RadiologyUniversity of WashingtonSeattleWashingtonUSA
| | | | - Peter S. Rabinovitch
- Department of Laboratory Medicine and PathologyUniversity of WashingtonSeattleWashingtonUSA
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Johannsen DL, Marlatt KL, Conley KE, Smith SR, Ravussin E. Metabolic adaptation is not observed after 8 weeks of overfeeding but energy expenditure variability is associated with weight recovery. Am J Clin Nutr 2019; 110:805-813. [PMID: 31204775 PMCID: PMC6766445 DOI: 10.1093/ajcn/nqz108] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 05/08/2019] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND A metabolic adaptation, defined as an increase in energy expenditure (EE) beyond what is expected with weight gain during overfeeding (OF), has been reported but also refuted. Much of the inconsistency stems from the difficulty in conducting large, well-controlled OF studies in humans. OBJECTIVES The primary aim of this study was to determine whether a metabolic adaptation to OF exists and if so, attenuates weight gain. METHODS Thirty-five young adults consumed 40% above their baseline energy requirements for 8 wk, and sleeping metabolic rate (SMR) and 24-h sedentary energy expenditure (24h-EE) were measured before and after OF. Subjects were asked to return for a 6-mo post-OF follow-up visit to measure body weight, body composition, and physical activity. RESULTS After adjusting for gains in fat-free mass and fat mass, SMR increased by 43 ± 123 kcal/d more than expected (P = 0.05) and 24h-EE by 23 ± 139 kcal/d (P = 0.34), indicating an overall lack of metabolic adaptation during OF despite a wide variability in the response. Among the 30 subjects who returned for the 6-mo follow-up visit, those who had a lower-than-predicted SMR (basal EE) retained more of the fat gained during OF. Likewise, subjects displaying a higher-than-predicted sedentary 24h-EE lost significantly more fat during the 6-mo follow-up. CONCLUSIONS Metabolic adaptation to OF was on average very small but variable between subjects, revealing "thrifty" or "spendthrift" metabolic phenotypes related to body weight loss 6 mo later. This trial was registered at clinicaltrials.gov as NCT01672632.
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Affiliation(s)
- Darcy L Johannsen
- Clinical Science, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA,Current address for DLJ: Laboratory of Biological Modeling, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kara L Marlatt
- Clinical Science, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA
| | - Kevin E Conley
- Department of Radiology, Bioengineering, Physiology and Biophysics, University of Washington, Seattle, WA 98195, USA
| | - Steven R Smith
- Translational Research Institute for Metabolism and Diabetes, Advent Health, Orlando, FL 32827, USA
| | - Eric Ravussin
- Clinical Science, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA,Address correspondence to ER (e-mail: )
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Liu SZ, Ali AS, Campbell MD, Kilroy K, Shankland EG, Roshanravan B, Marcinek DJ, Conley KE. Building strength, endurance, and mobility using an astaxanthin formulation with functional training in elderly. J Cachexia Sarcopenia Muscle 2018; 9:826-833. [PMID: 30259703 PMCID: PMC6204600 DOI: 10.1002/jcsm.12318] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 04/18/2018] [Accepted: 05/22/2018] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND Building both strength and endurance has been a challenge in exercise training in the elderly, but dietary supplements hold promise as agents for improving muscle adaptation. Here, we test a formulation of natural products (AX: astaxanthin, 12 mg and tocotrienol, 10 mg and zinc, 6 mg) with both anti-inflammatory and antioxidant properties in combination with exercise. We conducted a randomized, double-blind, placebo-controlled study of elderly subjects (65-82 years) on a daily oral dose with interval walking exercise on an incline treadmill. METHODS Forty-two subjects were fed AX or placebo for 4 months and trained 3 months (3×/week for 40-60 min) with increasing intervals of incline walking. Strength was measured as maximal voluntary force (MVC) in ankle dorsiflexion exercise, and tibialis anterior muscle size (cross-sectional area, CSA) was determined from magnetic resonance imaging. RESULTS Greater endurance (exercise time in incline walking, >50%) and distance in 6 min walk (>8%) accompanied training in both treatments. Increases in MVC by 14.4% (±6.2%, mean ± SEM, P < 0.02, paired t-test), CSA by 2.7% (±1.0%, P < 0.01), and specific force by 11.6% (MVC/CSA, ±6.0%, P = 0.05) were found with AX treatment, but no change was evident in these properties with placebo treatment (MVC, 2.9% ± 5.6%; CSA, 0.6% ± 1.2%; MVC/CSA, 2.4 ± 5.7%; P > 0.6 for all). CONCLUSIONS The AX formulation improved muscle strength and CSA in healthy elderly in addition to the elevation in endurance and walking distance found with exercise training alone. Thus, the AX formulation in combination with a functional training programme uniquely improved muscle strength, endurance, and mobility in the elderly.
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Affiliation(s)
- Sophia Z. Liu
- Translational Center for Metabolic Imaging Department of RadiologyUniversity of WashingtonSeattleWA
| | - Amir S. Ali
- Translational Center for Metabolic Imaging Department of RadiologyUniversity of WashingtonSeattleWA
| | - Matthew D. Campbell
- Translational Center for Metabolic Imaging Department of RadiologyUniversity of WashingtonSeattleWA
| | - Kevin Kilroy
- Translational Center for Metabolic Imaging Department of RadiologyUniversity of WashingtonSeattleWA
| | - Eric G. Shankland
- Translational Center for Metabolic Imaging Department of RadiologyUniversity of WashingtonSeattleWA
| | | | - David J. Marcinek
- Translational Center for Metabolic Imaging Department of RadiologyUniversity of WashingtonSeattleWA
- Department of BioengineeringUniversity of WashingtonSeattleWA
- Department of PathologyUniversity of WashingtonSeattleWAUSA
| | - Kevin E. Conley
- Translational Center for Metabolic Imaging Department of RadiologyUniversity of WashingtonSeattleWA
- Department of Physiology and BiophysicsUniversity of WashingtonSeattleWA
- Department of BioengineeringUniversity of WashingtonSeattleWA
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6
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Toledo FGS, Johannsen DL, Covington JD, Bajpeyi S, Goodpaster B, Conley KE, Ravussin E. Impact of prolonged overfeeding on skeletal muscle mitochondria in healthy individuals. Diabetologia 2018; 61:466-475. [PMID: 29150696 PMCID: PMC5770194 DOI: 10.1007/s00125-017-4496-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 10/17/2017] [Indexed: 12/01/2022]
Abstract
AIMS/HYPOTHESES Reduced mitochondrial capacity in skeletal muscle has been observed in obesity and type 2 diabetes. In humans, the aetiology of this abnormality is not well understood but the possibility that it is secondary to the stress of nutrient overload has been suggested. To test this hypothesis, we examined whether sustained overfeeding decreases skeletal muscle mitochondrial content or impairs function. METHODS Twenty-six healthy volunteers (21 men, 5 women, age 25.3 ± 4.5 years, BMI 25.5 ± 2.4 kg/m2) underwent a supervised protocol consisting of 8 weeks of high-fat overfeeding (40% over baseline energy requirements). Before and after overfeeding, we measured systemic fuel oxidation by indirect calorimetry and performed skeletal muscle biopsies to measure mitochondrial gene expression, content and function in vitro. Mitochondrial function in vivo was measured by 31P NMR spectroscopy. RESULTS With overfeeding, volunteers gained 7.7 ± 1.8 kg (% change 9.8 ± 2.3). Overfeeding increased fasting NEFA, LDL-cholesterol and insulin concentrations. Indirect calorimetry showed a shift towards greater reliance on lipid oxidation. In skeletal muscle tissue, overfeeding increased ceramide content, lipid droplet content and perilipin-2 mRNA expression. Phosphorylation of AMP-activated protein kinase was decreased. Overfeeding increased mRNA expression of certain genes coding for mitochondrial proteins (CS, OGDH, CPT1B, UCP3, ANT1). Despite the stress of nutrient overload, mitochondrial content and mitochondrial respiration in muscle did not change after overfeeding. Similarly, overfeeding had no effect on either the emission of reactive oxygen species or on mitochondrial function in vivo. CONCLUSIONS/INTERPRETATION Skeletal muscle mitochondria are significantly resilient to nutrient overload. The lower skeletal muscle mitochondrial oxidative capacity in human obesity is likely to be caused by reasons other than nutrient overload per se. TRIAL REGISTRATION ClinicalTrials.gov NCT01672632.
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Affiliation(s)
- Frederico G S Toledo
- Division of Endocrinology and Metabolism, Department of Medicine, University of Pittsburgh School of Medicine, 200 Lothrop Street, BST W1054, Pittsburgh, PA, 15261, USA.
| | | | | | - Sudip Bajpeyi
- Pennington Biomedical Research Center, Baton Rouge, LA, USA
- Department of Kinesiology, University of Texas El Paso, El Paso, TX, USA
| | - Bret Goodpaster
- Translational Research Institute for Metabolism and Diabetes, Orlando, FL, USA
| | - Kevin E Conley
- University of Washington Medical Center, Seattle, WA, USA
| | - Eric Ravussin
- Pennington Biomedical Research Center, Baton Rouge, LA, USA
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Ryu D, Zhang H, Ropelle ER, Sorrentino V, Mázala DAG, Mouchiroud L, Marshall PL, Campbell MD, Ali AS, Knowels GM, Bellemin S, Iyer SR, Wang X, Gariani K, Sauve AA, Cantó C, Conley KE, Walter L, Lovering RM, Chin ER, Jasmin BJ, Marcinek DJ, Menzies KJ, Auwerx J. NAD+ repletion improves muscle function in muscular dystrophy and counters global PARylation. Sci Transl Med 2017; 8:361ra139. [PMID: 27798264 DOI: 10.1126/scitranslmed.aaf5504] [Citation(s) in RCA: 187] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 09/12/2016] [Indexed: 12/25/2022]
Abstract
Neuromuscular diseases are often caused by inherited mutations that lead to progressive skeletal muscle weakness and degeneration. In diverse populations of normal healthy mice, we observed correlations between the abundance of mRNA transcripts related to mitochondrial biogenesis, the dystrophin-sarcoglycan complex, and nicotinamide adenine dinucleotide (NAD+) synthesis, consistent with a potential role for the essential cofactor NAD+ in protecting muscle from metabolic and structural degeneration. Furthermore, the skeletal muscle transcriptomes of patients with Duchene's muscular dystrophy (DMD) and other muscle diseases were enriched for various poly[adenosine 5'-diphosphate (ADP)-ribose] polymerases (PARPs) and for nicotinamide N-methyltransferase (NNMT), enzymes that are major consumers of NAD+ and are involved in pleiotropic events, including inflammation. In the mdx mouse model of DMD, we observed significant reductions in muscle NAD+ levels, concurrent increases in PARP activity, and reduced expression of nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting enzyme for NAD+ biosynthesis. Replenishing NAD+ stores with dietary nicotinamide riboside supplementation improved muscle function and heart pathology in mdx and mdx/Utr-/- mice and reversed pathology in Caenorhabditis elegans models of DMD. The effects of NAD+ repletion in mdx mice relied on the improvement in mitochondrial function and structural protein expression (α-dystrobrevin and δ-sarcoglycan) and on the reductions in general poly(ADP)-ribosylation, inflammation, and fibrosis. In combination, these studies suggest that the replenishment of NAD+ may benefit patients with muscular dystrophies or other neuromuscular degenerative conditions characterized by the PARP/NNMT gene expression signatures.
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Affiliation(s)
- Dongryeol Ryu
- Laboratory of Integrative and Systems Physiology, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Hongbo Zhang
- Laboratory of Integrative and Systems Physiology, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Eduardo R Ropelle
- Laboratory of Integrative and Systems Physiology, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.,Laboratory of Molecular Biology of Exercise, School of Applied Science, University of Campinas, CEP 13484-350 Limeira, São Paulo, Brazil
| | - Vincenzo Sorrentino
- Laboratory of Integrative and Systems Physiology, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Davi A G Mázala
- Department of Kinesiology, School of Public Health, University of Maryland, College Park, MD 20742, USA
| | - Laurent Mouchiroud
- Laboratory of Integrative and Systems Physiology, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Philip L Marshall
- Interdisciplinary School of Health Sciences, University of Ottawa Brain and Mind Research Institute and Centre for Neuromuscular Disease, Ottawa, Ontario K1H 8M5, Canada
| | - Matthew D Campbell
- Department of Radiology, University of Washington, Seattle, WA 98195, USA
| | - Amir Safi Ali
- Department of Radiology, University of Washington, Seattle, WA 98195, USA
| | - Gary M Knowels
- Department of Radiology, University of Washington, Seattle, WA 98195, USA
| | - Stéphanie Bellemin
- Centre de Génétique et de Physiologie Moléculaires et Cellulaires, Université Claude Bernard Lyon 1, CNRS UMR 5534, 69622 Villeurbanne, France
| | - Shama R Iyer
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Xu Wang
- Laboratory of Integrative and Systems Physiology, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Karim Gariani
- Laboratory of Integrative and Systems Physiology, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Anthony A Sauve
- Department of Pharmacology, Weill Cornell Medical School, New York, NY 10065, USA
| | - Carles Cantó
- Nestlé Institute of Health Sciences, 1015 Lausanne, Switzerland
| | - Kevin E Conley
- Department of Radiology, University of Washington, Seattle, WA 98195, USA
| | - Ludivine Walter
- Centre de Génétique et de Physiologie Moléculaires et Cellulaires, Université Claude Bernard Lyon 1, CNRS UMR 5534, 69622 Villeurbanne, France
| | - Richard M Lovering
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Eva R Chin
- Department of Kinesiology, School of Public Health, University of Maryland, College Park, MD 20742, USA
| | - Bernard J Jasmin
- Department of Cellular and Molecular Medicine and Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
| | - David J Marcinek
- Department of Radiology, University of Washington, Seattle, WA 98195, USA
| | - Keir J Menzies
- Laboratory of Integrative and Systems Physiology, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland. .,Interdisciplinary School of Health Sciences, University of Ottawa Brain and Mind Research Institute and Centre for Neuromuscular Disease, Ottawa, Ontario K1H 8M5, Canada
| | - Johan Auwerx
- Laboratory of Integrative and Systems Physiology, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
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Bajpeyi S, Pasarica M, Conley KE, Newcomer BR, Jubrias SA, Gamboa C, Murray K, Sereda O, Sparks LM, Smith SR. Pioglitazone-induced improvements in insulin sensitivity occur without concomitant changes in muscle mitochondrial function. Metabolism 2017; 69:24-32. [PMID: 28285649 DOI: 10.1016/j.metabol.2016.11.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 11/19/2016] [Accepted: 11/29/2016] [Indexed: 12/16/2022]
Abstract
AIMS Pioglitazone (Pio) is known to improve insulin sensitivity in skeletal muscle. However, the role of Pio in skeletal muscle lipid metabolism and skeletal muscle oxidative capacity is not clear. The aim of this study was to determine the effects of chronic Pio treatment on skeletal muscle mitochondrial activity in individuals with type 2 diabetes (T2D). MATERIALS AND METHODS Twenty-four participants with T2D (13M/11F 53.38±2.1years; BMI 36.47±1.1kg/m2) were randomized to either a placebo (CON, n=8) or a pioglitazone (PIO, n=16) group. Following 12weeks of treatment, we measured insulin sensitivity by hyperinsulinemic-euglycemic clamp (clamp), metabolic flexibility by calculating the change in respiratory quotient (ΔRQ) during the steady state of the clamp, intra- and extra-myocellular lipid content (IMCL and EMCL, respectively) by 1H magnetic resonance spectroscopy (1H-MRS) and muscle maximal ATP synthetic capacity (ATPmax) by 31P-MRS. RESULTS Following 12weeks of PIO treatment, insulin sensitivity (p<0.0005 vs. baseline) and metabolic flexibility (p<0.05 vs. CON) significantly increased. PIO treatment significantly decreased IMCL content and increased EMCL content in gastrocnemius, soleus and tibialis anterior muscles. ATPmax was unaffected by PIO treatment. CONCLUSIONS These results suggest that 12weeks of pioglitazone treatment improves insulin sensitivity, metabolic flexibility and myocellular lipid distribution without any effect on maximal ATP synthetic capacity in skeletal muscle. Consequently, pioglitazone-induced enhancements in insulin responsiveness and fuel utilization are independent of mitochondrial function.
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Affiliation(s)
- Sudip Bajpeyi
- Pennington Biomedical Research Center, 6400 Perkins Road, Baton Rouge, LA 70808, USA; Department of Kinesiology, University of Texas in El Paso, 500 University Ave, El Paso, TX 79968, USA
| | - Magdalena Pasarica
- Translational Research Institute for Metabolism and Diabetes, Florida Hospital, Orlando, FL 32804, USA
| | - Kevin E Conley
- Department of Radiology, University of Washington Medical Center, 1959 NE Pacific St, Seattle, WA 98195, USA
| | - Bradley R Newcomer
- Department of Clinical and Diagnostic Sciences, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Sharon A Jubrias
- Department of Radiology, University of Washington Medical Center, 1959 NE Pacific St, Seattle, WA 98195, USA
| | - Cecilia Gamboa
- Department of Kinesiology, University of Texas in El Paso, 500 University Ave, El Paso, TX 79968, USA
| | - Kori Murray
- Pennington Biomedical Research Center, 6400 Perkins Road, Baton Rouge, LA 70808, USA
| | - Olga Sereda
- Pennington Biomedical Research Center, 6400 Perkins Road, Baton Rouge, LA 70808, USA
| | - Lauren M Sparks
- Translational Research Institute for Metabolism and Diabetes, Florida Hospital, Orlando, FL 32804, USA; Sanford Burnham Prebys Medical Discovery Institute, Orlando, FL 32827, USA
| | - Steven R Smith
- Translational Research Institute for Metabolism and Diabetes, Florida Hospital, Orlando, FL 32804, USA; Sanford Burnham Prebys Medical Discovery Institute, Orlando, FL 32827, USA.
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9
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Sparks LM, Redman LM, Conley KE, Harper ME, Yi F, Hodges A, Eroshkin A, Costford SR, Gabriel ME, Shook C, Cornnell HH, Ravussin E, Smith SR. Effects of 12 Months of Caloric Restriction on Muscle Mitochondrial Function in Healthy Individuals. J Clin Endocrinol Metab 2017; 102:111-121. [PMID: 27778643 PMCID: PMC5413108 DOI: 10.1210/jc.2016-3211] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 10/21/2016] [Indexed: 11/19/2022]
Abstract
CONTEXT The effects of caloric restriction (CR) on in vivo muscle mitochondrial function in humans are controversial. OBJECTIVE We evaluated muscle mitochondrial function and associated transcriptional profiles in nonobese humans after 12 months of CR. DESIGN Individuals from an ancillary study of the CALERIE 2 randomized controlled trial were assessed at baseline and 12 months after a 25% CR or ad libitum (control) diet. SETTING The study was performed at Pennington Biomedical Research Center in Baton Rouge, LA. PARTICIPANTS Study participants included 51 (34 female subjects, 25 to 50 years of age) healthy nonobese individuals randomized to 1 of 2 groups (CR or control). INTERVENTION This study included 12 months of a 25% CR or ad libitum (control) diet. MAIN OUTCOMES In vivo mitochondrial function [maximal ATP synthesis rate (ATPmax), ATPflux/O2 (P/O)] was determined by 31P-magnetic resonance spectroscopy and optical spectroscopy, and body composition was determined by dual-energy X-ray absorptiometry. In a subset of individuals, a muscle biopsy was performed for transcriptional profiling via quantitative reverse transcription polymerase chain reaction and microarrays. RESULTS Weight, body mass index (BMI), fat, and fat-free mass (P < 0.001 for all) significantly decreased at month 12 after CR vs control. In vivo ATPmax and P/O were unaffected by 12 months of CR. Targeted transcriptional profiling showed no effects on pathways involved in mitochondrial biogenesis, function, or oxidative stress. A subgroup analysis according to baseline P/O demonstrated that a higher (vs lower) P/O was associated with notable improvements in ATPmax and P/O after CR. CONCLUSIONS In healthy nonobese humans, CR has no effect on muscle mitochondrial function; however, having a "more coupled" (versus "less coupled") phenotype enables CR-induced improvements in muscle mitochondrial function.
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Affiliation(s)
- Lauren M. Sparks
- Translational Research Institute for Metabolism and Diabetes, Florida Hospital, Orlando, Florida 32804;
- Clinical and Molecular Origins of Disease, Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida 32827;
| | - Leanne M. Redman
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana 70808;
| | - Kevin E. Conley
- Radiology,
- Physiology & Biophysics, and
- Bioengineering, University of Washington Medical Center, Seattle, Washington 98195;
| | - Mary-Ellen Harper
- Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, Ontario ON K1N 6N5, Canada;
| | - Fanchao Yi
- Translational Research Institute for Metabolism and Diabetes, Florida Hospital, Orlando, Florida 32804;
| | - Andrew Hodges
- Bioinformatics Core, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037; and
| | - Alexey Eroshkin
- Bioinformatics Core, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037; and
| | | | - Meghan E. Gabriel
- Clinical and Molecular Origins of Disease, Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida 32827;
| | - Cherie Shook
- Translational Research Institute for Metabolism and Diabetes, Florida Hospital, Orlando, Florida 32804;
| | - Heather H. Cornnell
- Translational Research Institute for Metabolism and Diabetes, Florida Hospital, Orlando, Florida 32804;
| | - Eric Ravussin
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana 70808;
| | - Steven R. Smith
- Translational Research Institute for Metabolism and Diabetes, Florida Hospital, Orlando, Florida 32804;
- Clinical and Molecular Origins of Disease, Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida 32827;
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10
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Sparks LM, Redman LM, Conley KE, Harper ME, Hodges A, Eroshkin A, Costford SR, Gabriel ME, Yi F, Shook C, Cornnell HH, Ravussin E, Smith SR. Differences in Mitochondrial Coupling Reveal a Novel Signature of Mitohormesis in Muscle of Healthy Individuals. J Clin Endocrinol Metab 2016; 101:4994-5003. [PMID: 27710240 PMCID: PMC5155692 DOI: 10.1210/jc.2016-2742] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
CONTEXT Reduced mitochondrial coupling (ATP/O2 [P/O]) is associated with sedentariness and insulin resistance. Interpreting the physiological relevance of P/O measured in vitro is challenging. OBJECTIVE To evaluate muscle mitochondrial function and associated transcriptional profiles in nonobese healthy individuals distinguished by their in vivo P/O. DESIGN Individuals from an ancillary study of Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy phase 2 were assessed at baseline. SETTING The study was performed at Pennington Biomedical Research Center. PARTICIPANTS Forty-seven (18 males, 26-50 y of age) sedentary, healthy nonobese individuals were divided into 2 groups based on their in vivo P/O. INTERVENTION None. Main Outcome(s): Body composition by dual-energy x-ray absorptiometry, in vivo mitochondrial function (P/O and maximal ATP synthetic capacity) by 31P-magnetic resonance spectroscopy and optical spectroscopy were measured. A muscle biopsy was performed to measure fiber type, transcriptional profiling (microarray), and protein expressions. RESULTS No differences in body composition, peak aerobic capacity, type I fiber content, or mitochondrial DNA copy number were observed between the 2 groups. Compared with the uncoupled group (lower P/O), the coupled group (higher P/O) had higher rates of maximal ATP synthetic capacity (maximal ATP synthetic capacity, P < .01). Transcriptomics analyses revealed higher expressions of genes involved in mitochondrial remodeling and the oxidative stress response in the coupled group. A trend for higher mitonuclear protein imbalance (P = .06) and an elevated mitochondrial unfolded protein response (heat shock protein 60 protein; P = .004) were also identified in the coupled group. CONCLUSIONS Higher muscle mitochondrial coupling is accompanied by an overall elevation in mitochondrial function, a novel transcriptional signature of oxidative stress and mitochondrial remodeling and indications of an mitochondrial unfolded protein response.
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Affiliation(s)
- Lauren M Sparks
- Translational Research Institute for Metabolism and Diabetes (L.M.S., F.Y., C.S., H.H.C., S.R.S.), Florida Hospital, Orlando, Florida 32804; Clinical and Molecular Origins of Disease (L.M.S., M.E.G., S.R.S.), Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida 32827; Pennington Biomedical Research Center (L.M.R., E.R.), Louisiana State University System, Baton Rouge, Louisiana 70808; Departments of Radiology, Physiology and Biophysics, and Bioengineering (K.E.C.), University of Washington Medical Center, Seattle, Washington 98195; Department of Biochemistry, Microbiology, and Immunology (M.-E.H.), University of Ottawa, Ottawa, Ontario ON K1N 6N5, Canada; Bioinformatics Core (A.H., A.E.), Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037; and Hospital for Sick Children (S.R.C.), Toronto, Ontario, ON M5G 1X8 Canada
| | - Leanne M Redman
- Translational Research Institute for Metabolism and Diabetes (L.M.S., F.Y., C.S., H.H.C., S.R.S.), Florida Hospital, Orlando, Florida 32804; Clinical and Molecular Origins of Disease (L.M.S., M.E.G., S.R.S.), Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida 32827; Pennington Biomedical Research Center (L.M.R., E.R.), Louisiana State University System, Baton Rouge, Louisiana 70808; Departments of Radiology, Physiology and Biophysics, and Bioengineering (K.E.C.), University of Washington Medical Center, Seattle, Washington 98195; Department of Biochemistry, Microbiology, and Immunology (M.-E.H.), University of Ottawa, Ottawa, Ontario ON K1N 6N5, Canada; Bioinformatics Core (A.H., A.E.), Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037; and Hospital for Sick Children (S.R.C.), Toronto, Ontario, ON M5G 1X8 Canada
| | - Kevin E Conley
- Translational Research Institute for Metabolism and Diabetes (L.M.S., F.Y., C.S., H.H.C., S.R.S.), Florida Hospital, Orlando, Florida 32804; Clinical and Molecular Origins of Disease (L.M.S., M.E.G., S.R.S.), Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida 32827; Pennington Biomedical Research Center (L.M.R., E.R.), Louisiana State University System, Baton Rouge, Louisiana 70808; Departments of Radiology, Physiology and Biophysics, and Bioengineering (K.E.C.), University of Washington Medical Center, Seattle, Washington 98195; Department of Biochemistry, Microbiology, and Immunology (M.-E.H.), University of Ottawa, Ottawa, Ontario ON K1N 6N5, Canada; Bioinformatics Core (A.H., A.E.), Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037; and Hospital for Sick Children (S.R.C.), Toronto, Ontario, ON M5G 1X8 Canada
| | - Mary-Ellen Harper
- Translational Research Institute for Metabolism and Diabetes (L.M.S., F.Y., C.S., H.H.C., S.R.S.), Florida Hospital, Orlando, Florida 32804; Clinical and Molecular Origins of Disease (L.M.S., M.E.G., S.R.S.), Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida 32827; Pennington Biomedical Research Center (L.M.R., E.R.), Louisiana State University System, Baton Rouge, Louisiana 70808; Departments of Radiology, Physiology and Biophysics, and Bioengineering (K.E.C.), University of Washington Medical Center, Seattle, Washington 98195; Department of Biochemistry, Microbiology, and Immunology (M.-E.H.), University of Ottawa, Ottawa, Ontario ON K1N 6N5, Canada; Bioinformatics Core (A.H., A.E.), Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037; and Hospital for Sick Children (S.R.C.), Toronto, Ontario, ON M5G 1X8 Canada
| | - Andrew Hodges
- Translational Research Institute for Metabolism and Diabetes (L.M.S., F.Y., C.S., H.H.C., S.R.S.), Florida Hospital, Orlando, Florida 32804; Clinical and Molecular Origins of Disease (L.M.S., M.E.G., S.R.S.), Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida 32827; Pennington Biomedical Research Center (L.M.R., E.R.), Louisiana State University System, Baton Rouge, Louisiana 70808; Departments of Radiology, Physiology and Biophysics, and Bioengineering (K.E.C.), University of Washington Medical Center, Seattle, Washington 98195; Department of Biochemistry, Microbiology, and Immunology (M.-E.H.), University of Ottawa, Ottawa, Ontario ON K1N 6N5, Canada; Bioinformatics Core (A.H., A.E.), Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037; and Hospital for Sick Children (S.R.C.), Toronto, Ontario, ON M5G 1X8 Canada
| | - Alexey Eroshkin
- Translational Research Institute for Metabolism and Diabetes (L.M.S., F.Y., C.S., H.H.C., S.R.S.), Florida Hospital, Orlando, Florida 32804; Clinical and Molecular Origins of Disease (L.M.S., M.E.G., S.R.S.), Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida 32827; Pennington Biomedical Research Center (L.M.R., E.R.), Louisiana State University System, Baton Rouge, Louisiana 70808; Departments of Radiology, Physiology and Biophysics, and Bioengineering (K.E.C.), University of Washington Medical Center, Seattle, Washington 98195; Department of Biochemistry, Microbiology, and Immunology (M.-E.H.), University of Ottawa, Ottawa, Ontario ON K1N 6N5, Canada; Bioinformatics Core (A.H., A.E.), Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037; and Hospital for Sick Children (S.R.C.), Toronto, Ontario, ON M5G 1X8 Canada
| | - Sheila R Costford
- Translational Research Institute for Metabolism and Diabetes (L.M.S., F.Y., C.S., H.H.C., S.R.S.), Florida Hospital, Orlando, Florida 32804; Clinical and Molecular Origins of Disease (L.M.S., M.E.G., S.R.S.), Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida 32827; Pennington Biomedical Research Center (L.M.R., E.R.), Louisiana State University System, Baton Rouge, Louisiana 70808; Departments of Radiology, Physiology and Biophysics, and Bioengineering (K.E.C.), University of Washington Medical Center, Seattle, Washington 98195; Department of Biochemistry, Microbiology, and Immunology (M.-E.H.), University of Ottawa, Ottawa, Ontario ON K1N 6N5, Canada; Bioinformatics Core (A.H., A.E.), Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037; and Hospital for Sick Children (S.R.C.), Toronto, Ontario, ON M5G 1X8 Canada
| | - Meghan E Gabriel
- Translational Research Institute for Metabolism and Diabetes (L.M.S., F.Y., C.S., H.H.C., S.R.S.), Florida Hospital, Orlando, Florida 32804; Clinical and Molecular Origins of Disease (L.M.S., M.E.G., S.R.S.), Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida 32827; Pennington Biomedical Research Center (L.M.R., E.R.), Louisiana State University System, Baton Rouge, Louisiana 70808; Departments of Radiology, Physiology and Biophysics, and Bioengineering (K.E.C.), University of Washington Medical Center, Seattle, Washington 98195; Department of Biochemistry, Microbiology, and Immunology (M.-E.H.), University of Ottawa, Ottawa, Ontario ON K1N 6N5, Canada; Bioinformatics Core (A.H., A.E.), Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037; and Hospital for Sick Children (S.R.C.), Toronto, Ontario, ON M5G 1X8 Canada
| | - Fanchao Yi
- Translational Research Institute for Metabolism and Diabetes (L.M.S., F.Y., C.S., H.H.C., S.R.S.), Florida Hospital, Orlando, Florida 32804; Clinical and Molecular Origins of Disease (L.M.S., M.E.G., S.R.S.), Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida 32827; Pennington Biomedical Research Center (L.M.R., E.R.), Louisiana State University System, Baton Rouge, Louisiana 70808; Departments of Radiology, Physiology and Biophysics, and Bioengineering (K.E.C.), University of Washington Medical Center, Seattle, Washington 98195; Department of Biochemistry, Microbiology, and Immunology (M.-E.H.), University of Ottawa, Ottawa, Ontario ON K1N 6N5, Canada; Bioinformatics Core (A.H., A.E.), Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037; and Hospital for Sick Children (S.R.C.), Toronto, Ontario, ON M5G 1X8 Canada
| | - Cherie Shook
- Translational Research Institute for Metabolism and Diabetes (L.M.S., F.Y., C.S., H.H.C., S.R.S.), Florida Hospital, Orlando, Florida 32804; Clinical and Molecular Origins of Disease (L.M.S., M.E.G., S.R.S.), Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida 32827; Pennington Biomedical Research Center (L.M.R., E.R.), Louisiana State University System, Baton Rouge, Louisiana 70808; Departments of Radiology, Physiology and Biophysics, and Bioengineering (K.E.C.), University of Washington Medical Center, Seattle, Washington 98195; Department of Biochemistry, Microbiology, and Immunology (M.-E.H.), University of Ottawa, Ottawa, Ontario ON K1N 6N5, Canada; Bioinformatics Core (A.H., A.E.), Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037; and Hospital for Sick Children (S.R.C.), Toronto, Ontario, ON M5G 1X8 Canada
| | - Heather H Cornnell
- Translational Research Institute for Metabolism and Diabetes (L.M.S., F.Y., C.S., H.H.C., S.R.S.), Florida Hospital, Orlando, Florida 32804; Clinical and Molecular Origins of Disease (L.M.S., M.E.G., S.R.S.), Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida 32827; Pennington Biomedical Research Center (L.M.R., E.R.), Louisiana State University System, Baton Rouge, Louisiana 70808; Departments of Radiology, Physiology and Biophysics, and Bioengineering (K.E.C.), University of Washington Medical Center, Seattle, Washington 98195; Department of Biochemistry, Microbiology, and Immunology (M.-E.H.), University of Ottawa, Ottawa, Ontario ON K1N 6N5, Canada; Bioinformatics Core (A.H., A.E.), Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037; and Hospital for Sick Children (S.R.C.), Toronto, Ontario, ON M5G 1X8 Canada
| | - Eric Ravussin
- Translational Research Institute for Metabolism and Diabetes (L.M.S., F.Y., C.S., H.H.C., S.R.S.), Florida Hospital, Orlando, Florida 32804; Clinical and Molecular Origins of Disease (L.M.S., M.E.G., S.R.S.), Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida 32827; Pennington Biomedical Research Center (L.M.R., E.R.), Louisiana State University System, Baton Rouge, Louisiana 70808; Departments of Radiology, Physiology and Biophysics, and Bioengineering (K.E.C.), University of Washington Medical Center, Seattle, Washington 98195; Department of Biochemistry, Microbiology, and Immunology (M.-E.H.), University of Ottawa, Ottawa, Ontario ON K1N 6N5, Canada; Bioinformatics Core (A.H., A.E.), Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037; and Hospital for Sick Children (S.R.C.), Toronto, Ontario, ON M5G 1X8 Canada
| | - Steven R Smith
- Translational Research Institute for Metabolism and Diabetes (L.M.S., F.Y., C.S., H.H.C., S.R.S.), Florida Hospital, Orlando, Florida 32804; Clinical and Molecular Origins of Disease (L.M.S., M.E.G., S.R.S.), Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida 32827; Pennington Biomedical Research Center (L.M.R., E.R.), Louisiana State University System, Baton Rouge, Louisiana 70808; Departments of Radiology, Physiology and Biophysics, and Bioengineering (K.E.C.), University of Washington Medical Center, Seattle, Washington 98195; Department of Biochemistry, Microbiology, and Immunology (M.-E.H.), University of Ottawa, Ottawa, Ontario ON K1N 6N5, Canada; Bioinformatics Core (A.H., A.E.), Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037; and Hospital for Sick Children (S.R.C.), Toronto, Ontario, ON M5G 1X8 Canada
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11
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Abstract
Mitochondria oxidize substrates to generate the ATP that fuels muscle contraction and locomotion. This review focuses on three steps in oxidative phosphorylation that have independent roles in setting the overall mitochondrial ATP flux and thereby have direct impact on locomotion. The first is the electron transport chain, which sets the pace for oxidation. New studies indicate that the electron transport chain capacity per mitochondria declines with age and disease, but can be revived by both acute and chronic treatments. The resulting higher ATP production is reflected in improved muscle power output and locomotory performance. The second step is the coupling of ATP supply from O2 uptake (mitochondrial coupling efficiency). Treatments that elevate mitochondrial coupling raise both exercise efficiency and the capacity for sustained exercise in both young and old muscle. The final step is ATP synthesis itself, which is under dynamic control at multiple sites to provide the 50-fold range of ATP flux between resting muscle and exercise at the mitochondrial capacity. Thus, malleability at sites in these subsystems of oxidative phosphorylation has an impact on ATP flux, with direct effects on exercise performance. Interventions are emerging that target these three independent subsystems to provide many paths to improve ATP flux and elevate the muscle performance lost to inactivity, age or disease.
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Affiliation(s)
- Kevin E Conley
- Departments of Radiology, Physiology & Biophysics, and Bioengineering, University of Washington Medical Center, Seattle, WA 98195, USA
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12
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Roshanravan B, Kestenbaum B, Gamboa J, Jubrias SA, Ayers E, Curtin L, Himmelfarb J, de Boer IH, Conley KE. CKD and Muscle Mitochondrial Energetics. Am J Kidney Dis 2016; 68:658-659. [PMID: 27312460 DOI: 10.1053/j.ajkd.2016.05.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 05/06/2016] [Indexed: 12/22/2022]
Affiliation(s)
- Baback Roshanravan
- University of Washington Kidney Research Institute, Seattle, Washington.
| | - Bryan Kestenbaum
- University of Washington Kidney Research Institute, Seattle, Washington
| | - Jorge Gamboa
- Vanderbilt University Medical Center, Nashville, Tennessee
| | | | - Ernest Ayers
- University of Washington Kidney Research Institute, Seattle, Washington
| | - Laura Curtin
- University of Washington Kidney Research Institute, Seattle, Washington
| | | | - Ian H de Boer
- University of Washington Kidney Research Institute, Seattle, Washington
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13
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Conley KE, Ali AS, Flores B, Jubrias SA, Shankland EG. Mitochondrial NAD(P)H In vivo: Identifying Natural Indicators of Oxidative Phosphorylation in the (31)P Magnetic Resonance Spectrum. Front Physiol 2016; 7:45. [PMID: 27065875 PMCID: PMC4812112 DOI: 10.3389/fphys.2016.00045] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 02/01/2016] [Indexed: 01/20/2023] Open
Abstract
Natural indicators provide intrinsic probes of metabolism, biogenesis and oxidative protection. Nicotinamide adenine dinucleotide metabolites (NAD(P)) are one class of indicators that have roles as co-factors in oxidative phosphorylation, glycolysis, and anti-oxidant protection, as well as signaling in the mitochondrial biogenesis pathway. These many roles are made possible by the distinct redox states (NAD(P)(+) and NAD(P)H), which are compartmentalized between cytosol and mitochondria. Here we provide evidence for detection of NAD(P)(+) and NAD(P)H in separate mitochondrial and cytosol pools in vivo in human tissue by phosphorus magnetic resonance spectroscopy ((31)P MRS). These NAD(P) pools are identified by chemical standards (NAD(+), NADP(+), and NADH) and by physiological tests. A unique resonance reflecting mitochondrial NAD(P)H is revealed by the changes elicited by elevation of mitochondrial oxidation. The decline of NAD(P)H with oxidation is matched by a stoichiometric rise in the NAD(P)(+) peak. This unique resonance also provides a measure of the improvement in mitochondrial oxidation that parallels the greater phosphorylation found after exercise training in these elderly subjects. The implication is that the dynamics of the mitochondrial NAD(P)H peak provides an intrinsic probe of the reversal of mitochondrial dysfunction in elderly muscle. Thus, non-invasive detection of NAD(P)(+) and NAD(P)H in cytosol vs. mitochondria yields natural indicators of redox compartmentalization and sensitive intrinsic probes of the improvement of mitochondrial function with an intervention in human tissues in vivo. These natural indicators hold the promise of providing mechanistic insight into metabolism and mitochondrial function in vivo in a range of tissues in health, disease and with treatment.
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Affiliation(s)
- Kevin E Conley
- Department of Radiology, University of Washington Medical CenterSeattle, WA, USA; Department of Physiology and Biophysics, University of Washington Medical CenterSeattle, WA, USA; Department of Bioengineering, University of Washington Medical CenterSeattle, WA, USA
| | - Amir S Ali
- Department of Radiology, University of Washington Medical Center Seattle, WA, USA
| | - Brandon Flores
- Department of Radiology, University of Washington Medical Center Seattle, WA, USA
| | - Sharon A Jubrias
- Department of Radiology, University of Washington Medical Center Seattle, WA, USA
| | - Eric G Shankland
- Department of Radiology, University of Washington Medical Center Seattle, WA, USA
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14
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Mischley LK, Conley KE, Shankland EG, Kavanagh TJ, Rosenfeld ME, Duda JE, White CC, Wilbur TK, De La Torre PU, Padowski JM. Central nervous system uptake of intranasal glutathione in Parkinson's disease. NPJ Parkinsons Dis 2016; 2:16002. [PMID: 28725693 PMCID: PMC5516583 DOI: 10.1038/npjparkd.2016.2] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 12/03/2015] [Accepted: 12/10/2015] [Indexed: 11/16/2022] Open
Abstract
Glutathione (GSH) is depleted early in the course of Parkinson's disease (PD), and deficiency has been shown to perpetuate oxidative stress, mitochondrial dysfunction, impaired autophagy, and cell death. GSH repletion has been proposed as a therapeutic intervention. The objective of this study was to evaluate whether intranasally administered reduced GSH, (in)GSH, is capable of augmenting central nervous system GSH concentrations, as determined by magnetic resonance spectroscopy in 15 participants with mid-stage PD. After baseline GSH measurement, 200 mg (in)GSH was self-administered inside the scanner without repositioning, then serial GSH levels were obtained over ~1 h. Statistical significance was determined by one-way repeated measures analysis of variance. Overall, (in)GSH increased brain GSH relative to baseline (P<0.001). There was no increase in GSH 8 min after administration, although it was significantly higher than baseline at all of the remaining time points (P<0.01). This study is the first to demonstrate that intranasal administration of GSH elevates brain GSH levels. This increase persists at least 1 h in subjects with PD. Further dose-response and steady-state administration studies will be required to optimize the dosing schedule for future trials to evaluate therapeutic efficacy.
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Affiliation(s)
- Laurie K Mischley
- Department of Radiology, University of Washington (UW), Seattle, WA, USA
- Graduate Program in Nutritional Sciences, School of Public Health, University of Washington, Seattle, WA, USA
- School of Naturopathic Medicine, Bastyr University Research Institute, Kenmore, WA, USA
| | - Kevin E Conley
- Department of Radiology, University of Washington (UW), Seattle, WA, USA
| | - Eric G Shankland
- Department of Radiology, University of Washington (UW), Seattle, WA, USA
| | - Terrance J Kavanagh
- Department of Environmental & Occupational Health Sciences, School of Public Health, University of Washington, Seattle, WA, USA
| | - Michael E Rosenfeld
- Graduate Program in Nutritional Sciences, School of Public Health, University of Washington, Seattle, WA, USA
- Department of Environmental & Occupational Health Sciences, School of Public Health, University of Washington, Seattle, WA, USA
| | - John E Duda
- Michael J. Crescenz VA Medical Center, Philadelphia, PA, USA
- Department of Neurology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Collin C White
- Department of Environmental & Occupational Health Sciences, School of Public Health, University of Washington, Seattle, WA, USA
| | - Timothy K Wilbur
- Department of Radiology, University of Washington (UW), Seattle, WA, USA
| | - Prysilla U De La Torre
- Department of Radiology, University of Washington (UW), Seattle, WA, USA
- School of Naturopathic Medicine, Bastyr University Research Institute, Kenmore, WA, USA
| | - Jeannie M Padowski
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, USA
- Department of Experimental and Systems Pharmacology, College of Pharmacy, Washington State University, Spokane, WA, USA
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15
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Ortega JO, Lindstedt SL, Nelson FE, Jubrias SA, Kushmerick MJ, Conley KE. Muscle force, work and cost: a novel technique to revisit the Fenn effect. ACTA ACUST UNITED AC 2015; 218:2075-82. [PMID: 25964423 DOI: 10.1242/jeb.114512] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 04/29/2015] [Indexed: 11/20/2022]
Abstract
Muscle produces force by forming cross-bridges, using energy released from ATP. While the magnitude and duration of force production primarily determine the energy requirement, nearly a century ago Fenn observed that muscle shortening or lengthening influenced energetic cost of contraction. When work is done by the muscle, the energy cost is increased and when work is done on the muscle the energy cost is reduced. However, the magnitude of the 'Fenn effect' and its mirror ('negative Fenn effect') have not been quantitatively resolved. We describe a new technique coupling magnetic resonance spectroscopy with an in vivo force clamp that can directly quantify the Fenn effect [E=I+W, energy liberated (E) equals the energy cost of isometric force production (I) plus the work done (W)] and the negative Fenn effect (E=I-W) for one muscle, the first dorsal interosseous (FDI). ATP cost was measured during a series of contractions, each of which occurred at a constant force and for a constant duration, thus constant force-time integral (FTI). In all subjects, as the FTI increased with load, there was a proportional linear increase in energy cost. In addition, the cost of producing force greatly increased when the muscle shortened, and was slightly reduced during lengthening contraction. These results, though limited to a single muscle, contraction velocity and muscle length change, do quantitatively support the Fenn effect. We speculate that they also suggest that an elastic element within the FDI muscle functions to preserve the force generated within the cross-bridges.
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Affiliation(s)
- Justus O Ortega
- Department of Kinesiology & Recreation Administration, Humboldt State University, Arcata, CA 95521, USA Department of Radiology, University of Washington Medical Center, Seattle, WA 98195, USA
| | - Stan L Lindstedt
- Department of Biological Sciences, Northern Arizona University, South Beaver Street, Flagstaff, AZ 86001, USA
| | - Frank E Nelson
- Department of Radiology, University of Washington Medical Center, Seattle, WA 98195, USA
| | - Sharon A Jubrias
- Department of Radiology, University of Washington Medical Center, Seattle, WA 98195, USA
| | - Martin J Kushmerick
- Department of Radiology, University of Washington Medical Center, Seattle, WA 98195, USA
| | - Kevin E Conley
- Department of Radiology, University of Washington Medical Center, Seattle, WA 98195, USA Department of Physiology & Biophysics, University of Washington Medical Center, Seattle, WA 98195, USA Department of Bioengineering, University of Washington Medical Center, Seattle, WA 98105, USA
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16
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Santanasto AJ, Glynn NW, Jubrias SA, Conley KE, Boudreau RM, Amati F, Mackey DC, Simonsick EM, Strotmeyer ES, Coen PM, Goodpaster BH, Newman AB. Skeletal Muscle Mitochondrial Function and Fatigability in Older Adults. J Gerontol A Biol Sci Med Sci 2014; 70:1379-85. [PMID: 25167867 DOI: 10.1093/gerona/glu134] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Accepted: 06/28/2014] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Fatigability increases while the capacity for mitochondrial energy production tends to decrease significantly with age. Thus, diminished mitochondrial function may contribute to higher levels of fatigability in older adults. METHODS The relationship between fatigability and skeletal muscle mitochondrial function was examined in 30 participants aged 78.5 ± 5.0 years (47% female, 93% white), with a body mass index of 25.9 ± 2.7 kg/m(2) and usual gait-speed of 1.2 ± 0.2 m/s. Fatigability was defined using rating of perceived exertion (6-20 point Borg scale) after a 5-minute treadmill walk at 0.72 m/s. Phosphocreatine recovery in the quadriceps was measured using (31)P magnetic resonance spectroscopy and images of the quadriceps were captured to calculate quadriceps volume. ATPmax (mM ATP/s) and oxidative capacity of the quadriceps (ATPmax·Quadriceps volume) were calculated. Peak aerobic capacity (VO2peak) was measured using a modified Balke protocol. RESULTS ATPmax·Quadriceps volume was associated with VO2peak and was 162.61mM ATP·mL/s lower (p = .03) in those with high (rating of perceived exertion ≥10) versus low (rating of perceived exertion ≤9) fatigability. Participants with high fatigability required a significantly higher proportion of VO2peak to walk at 0.72 m/s compared with those with low fatigability (58.7 ± 19.4% vs 44.9 ± 13.2%, p < .05). After adjustment for age and sex, higher ATPmax was associated with lower odds of having high fatigability (odds ratio: 0.34, 95% CI: 0.11-1.01, p = .05). CONCLUSIONS Lower capacity for oxidative phosphorylation in the quadriceps, perhaps by contributing to lower VO2peak, is associated with higher fatigability in older adults.
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Affiliation(s)
- Adam J Santanasto
- Department of Epidemiology, Center for Aging and Population Health, Graduate School of Public Health, University of Pittsburgh, Pennsylvania
| | - Nancy W Glynn
- Department of Epidemiology, Center for Aging and Population Health, Graduate School of Public Health, University of Pittsburgh, Pennsylvania.
| | - Sharon A Jubrias
- Translational Center for Metabolic Imaging, University of Washington, Seattle
| | - Kevin E Conley
- Translational Center for Metabolic Imaging, University of Washington, Seattle
| | - Robert M Boudreau
- Department of Epidemiology, Center for Aging and Population Health, Graduate School of Public Health, University of Pittsburgh, Pennsylvania
| | - Francesca Amati
- Division of Endocrinology and Metabolism, School of Medicine, University of Pittsburgh, Pennsylvania
| | - Dawn C Mackey
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, Canada
| | - Eleanor M Simonsick
- Translational Gerontology Branch, National Institute on Aging, Baltimore, Maryland
| | - Elsa S Strotmeyer
- Department of Epidemiology, Center for Aging and Population Health, Graduate School of Public Health, University of Pittsburgh, Pennsylvania
| | - Paul M Coen
- Division of Endocrinology and Metabolism, School of Medicine, University of Pittsburgh, Pennsylvania. Department of Health and Physical Activity, School of Education, University of Pittsburgh, Pennsylvania. Present address: Florida Hospital-Sanford
- Burnham Translational Research Institute for Metabolism and Diabetes, Orlando
| | - Bret H Goodpaster
- Division of Endocrinology and Metabolism, School of Medicine, University of Pittsburgh, Pennsylvania. Present address: Florida Hospital-Sanford
- Burnham Translational Research Institute for Metabolism and Diabetes, Orlando
| | - Anne B Newman
- Department of Epidemiology, Center for Aging and Population Health, Graduate School of Public Health, University of Pittsburgh, Pennsylvania
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Padowski JM, Weaver KE, Richards TL, Laurino MY, Samii A, Aylward EH, Conley KE. Neurochemical correlates of caudate atrophy in Huntington's disease. Mov Disord 2014; 29:327-35. [PMID: 24442623 DOI: 10.1002/mds.25801] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 11/19/2013] [Accepted: 12/09/2013] [Indexed: 11/11/2022] Open
Abstract
The precise pathogenic mechanisms of Huntington's disease (HD) are unknown but can be tested in vivo using proton magnetic resonance spectroscopy ((1)H MRS) to measure neurochemical changes. The objective of this study was to evaluate neurochemical differences in HD gene mutation carriers (HGMCs) versus controls and to investigate relationships among function, brain structure, and neurochemistry in HD. Because previous (1)H MRS studies have yielded varied conclusions about HD neurochemical changes, an additional goal was to compare two (1)H MRS data analysis approaches. HGMCs with premanifest to early HD and controls underwent evaluation of motor function, magnetic resonance imaging, and localized (1)H MRS in the caudate and the frontal lobe. Analytical approaches that were tested included absolute quantitation (unsuppressed water signal as an internal reference) and relative quantification (calculating ratios of all neurochemical signals within a voxel). We identified a suite of neurochemicals that were reduced in concentration proportionally to loss of caudate volume in HGMCs. Caudate concentrations of N-acetylaspartate (NAA), creatine, choline, and caudate and frontal lobe concentrations of glutamate plus glutamine (Glx) and glutamate were correlated with caudate volume in HGMCs. The relative, but not the absolute, quantitation approach revealed disease-related differences; the Glx signal was decreased relative to other neurochemicals in the caudate of HGMCs versus controls. This is the first study to demonstrate a correlation among structure, function, and chemical measures in HD brain. Additionally, we demonstrate that a relative quantitation approach may enable the magnification of subtle differences between groups. Observation of decreased Glx suggests that glutamate signaling may be disrupted relatively early in HD, which has important implications for therapeutic approaches.
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Affiliation(s)
- Jeannie M Padowski
- Department of Radiology, University of Washington School of Medicine, Seattle, Washington, USA; Integrated Brain Imaging Center, University of Washington School of Medicine, Seattle, Washington, USA
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Gan Z, Rumsey J, Hazen BC, Lai L, Leone TC, Vega RB, Xie H, Conley KE, Auwerx J, Smith SR, Olson EN, Kralli A, Kelly DP. Nuclear receptor/microRNA circuitry links muscle fiber type to energy metabolism. J Clin Invest 2013; 123:2564-75. [PMID: 23676496 DOI: 10.1172/jci67652] [Citation(s) in RCA: 157] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Accepted: 03/08/2013] [Indexed: 11/17/2022] Open
Abstract
The mechanisms involved in the coordinate regulation of the metabolic and structural programs controlling muscle fitness and endurance are unknown. Recently, the nuclear receptor PPARβ/δ was shown to activate muscle endurance programs in transgenic mice. In contrast, muscle-specific transgenic overexpression of the related nuclear receptor, PPARα, results in reduced capacity for endurance exercise. We took advantage of the divergent actions of PPARβ/δ and PPARα to explore the downstream regulatory circuitry that orchestrates the programs linking muscle fiber type with energy metabolism. Our results indicate that, in addition to the well-established role in transcriptional control of muscle metabolic genes, PPARβ/δ and PPARα participate in programs that exert opposing actions upon the type I fiber program through a distinct muscle microRNA (miRNA) network, dependent on the actions of another nuclear receptor, estrogen-related receptor γ (ERRγ). Gain-of-function and loss-of-function strategies in mice, together with assessment of muscle biopsies from humans, demonstrated that type I muscle fiber proportion is increased via the stimulatory actions of ERRγ on the expression of miR-499 and miR-208b. This nuclear receptor/miRNA regulatory circuit shows promise for the identification of therapeutic targets aimed at maintaining muscle fitness in a variety of chronic disease states, such as obesity, skeletal myopathies, and heart failure.
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Affiliation(s)
- Zhenji Gan
- Diabetes and Obesity Research Center, Sanford-Burnham Medical Research Institute, Orlando, Florida 32827, USA
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Layec G, Trinity JD, Hart CR, Hopker J, Passfield L, Coen PM, Conley KE, Hunter GR, Fisher G, Ferguson RA, Sasaki K, Malatesta D, Maffiuletti NA, Borrani F, Minetti AE, Rice CL, Dalton BH, McNeil CJ, Power GA, Manini TM. Comments on point:counterpoint: skeletal muscle mechanical efficiency does/does not increase with age. J Appl Physiol (1985) 2013; 114:1114-8. [PMID: 23588541 PMCID: PMC6208486 DOI: 10.1152/japplphysiol.00185.2013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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20
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Conley KE, Amara CE, Bajpeyi S, Costford SR, Murray K, Jubrias SA, Arakaki L, Marcinek DJ, Smith SR. Higher mitochondrial respiration and uncoupling with reduced electron transport chain content in vivo in muscle of sedentary versus active subjects. J Clin Endocrinol Metab 2013; 98:129-36. [PMID: 23150693 PMCID: PMC3537085 DOI: 10.1210/jc.2012-2967] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
OBJECTIVE This study investigated the disparity between muscle metabolic rate and mitochondrial metabolism in human muscle of sedentary vs. active individuals. RESEARCH DESIGN AND METHODS Chronic activity level was characterized by a physical activity questionnaire and a triaxial accelerometer as well as a maximal oxygen uptake test. The ATP and O(2) fluxes and mitochondrial coupling (ATP/O(2) or P/O) in resting muscle as well as mitochondrial capacity (ATP(max)) were determined in vivo in human vastus lateralis muscle using magnetic resonance and optical spectroscopy on 24 sedentary and seven active subjects. Muscle biopsies were analyzed for electron transport chain content (using complex III as a representative marker) and mitochondrial proteins associated with antioxidant protection. RESULTS Sedentary muscle had lower electron transport chain complex content (65% of the active group) in proportion to the reduction in ATP(max) (0.69 ± 0.07 vs. 1.07 ± 0.06 mM sec(-1)) as compared with active subjects. This lower ATP(max) paired with an unchanged O(2) flux in resting muscle between groups resulted in a doubling of O(2) flux per ATP(max) (3.3 ± 0.3 vs. 1.7 ± 0.2 μM O(2) per mM ATP) that reflected mitochondrial uncoupling (P/O = 1.41 ± 0.1 vs. 2.1 ± 0.3) and greater UCP3/complex III (6.0 ± 0.7 vs. 3.8 ± 0.3) in sedentary vs. active subjects. CONCLUSION A smaller mitochondrial pool serving the same O(2) flux resulted in elevated mitochondrial respiration in sedentary muscle. In addition, uncoupling contributed to this higher mitochondrial respiration. This finding resolves the paradox of stable muscle metabolism but greater mitochondrial respiration in muscle of inactive vs. active subjects.
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Affiliation(s)
- Kevin E Conley
- Department of Radiology, University of Washington Medical Center, Box 357115, Seattle, Washington 98195-7115, USA.
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21
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Conley KE, Jubrias SA, Cress ME, Esselman PC. Elevated energy coupling and aerobic capacity improves exercise performance in endurance-trained elderly subjects. Exp Physiol 2012. [PMID: 23204291 DOI: 10.1113/expphysiol.2012.069633] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Increased maximal oxygen uptake (V(O(2)max)), mitochondrial capacity and energy coupling efficiency are reported after endurance training (ET) in adult subjects. Here we test whether leg exercise performance (power output of the legs, P(max), at V(O(2)max)) reflects these improvements with ET in the elderly. Fifteen male and female subjects were endurance trained for a 6 month programme, with 13 subjects (69.5 ± 1.2 years old, range 65-80 years old; n = 7 males; n = 6 females) completing the study. This training significantly improved P(max) (Δ17%; P = 0.003), V(O(2)max) (Δ5.4%; P = 0.021) and the increment in oxygen uptake (V(O(2))) above resting (ΔV(O(2)m-r) = V(O(2)max) - V(O(2)rest; Δ9%; P < 0.02). In addition, evidence of improved energy coupling came from elevated leg power output per unit V(O(2))at the aerobic capacity [Δ(P(max)/ΔV(O(2)m-r)); P = 0.02] and during submaximal exercise in the ramp test as measured by delta efficiency (ΔP(ex)/ΔV(O(2)); P = 0.04). No change was found in blood lactate, muscle glycolysis or fibre type. The rise in P(max) paralleled the improvement in muscle oxidative phosphorylation capacity (ATP(max)) in these subjects. In addition, the greater exercise energy coupling [Δ(P(max)/ΔV(O(2)m-r)) and delta efficiency] was accompanied by increased mitochondrial energy coupling as measured by elevated ATP production per unit mitochondrial content in these subjects. These results suggest that leg exercise performance benefits from elevations in energy coupling and oxidative phosphorylation capacity at both the whole-body and muscle levels that accompany endurance training in the elderly.
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Affiliation(s)
- Kevin E Conley
- Department of Radiology, Box 357115, University of Washington Medical Center, Seattle, WA 98195-7115, USA.
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Abstract
A reduction in exercise efficiency accompanies ageing in humans. Here we evaluated the impact of changes in the contractile-coupling and mitochondrial-coupling efficiencies on the reduction in exercise efficiency in the elderly. Nine adult (mean, 38.8 years old) and 40 elderly subjects (mean, 68.8 years old) performed a cycle ergometer test to measure O2 uptake and leg power output up to the aerobic limit ( ). Reduced leg power output per unit O2 uptake was reflected in a drop in delta efficiency (εD) from 0.27 ± 0.01 (mean ± SEM) in adults to 0.22 ± 0.01 in the elderly group. Similar declines with age were apparent for both the leg power output at and the ATP generation capacity (ATPmax) determined in vivo using (31)P magnetic resonance spectroscopy. These similar declines resulted in unchanged contractile-coupling efficiency values (εC) in the adult (0.50 ± 0.05) versus the elderly group (0.58 ± 0.04) and agreed with independent measures of muscle contractile-coupling efficiency in human quadriceps (0.5). The mitochondrial-coupling efficiency calculated from the ratio of delta to contractile-coupling efficiencies in the adults (εD/εC = 0.58 ± 0.08) corresponded to values for well-coupled mitochondria (0.6); however, εD/εC was significantly lower in the elderly subjects (0.44 ± 0.03). Conversion of ATPmax per mitochondrial volume (ATPmax/Vv[mt,f]) reported in these groups into thermodynamic units confirmed this drop in mitochondrial-coupling efficiency from 0.57 ± 0.08 in adults to 0.41 ± 0.03 in elderly subjects. Thus, two independent methods revealed that reduced mitochondrial-coupling efficiency was a key part of the drop in exercise efficiency in these elderly subjects and may be an important part of the loss of exercise performance with age.
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Affiliation(s)
- Kevin E Conley
- Department of Radiology, Box 357115, University of Washington Medical Center, Seattle, WA 98195-7115, USA.
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Coen PM, Jubrias SA, Distefano G, Amati F, Mackey DC, Glynn NW, Manini TM, Wohlgemuth SE, Leeuwenburgh C, Cummings SR, Newman AB, Ferrucci L, Toledo FGS, Shankland E, Conley KE, Goodpaster BH. Skeletal muscle mitochondrial energetics are associated with maximal aerobic capacity and walking speed in older adults. J Gerontol A Biol Sci Med Sci 2012; 68:447-55. [PMID: 23051977 DOI: 10.1093/gerona/gls196] [Citation(s) in RCA: 217] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Lower ambulatory performance with aging may be related to a reduced oxidative capacity within skeletal muscle. This study examined the associations between skeletal muscle mitochondrial capacity and efficiency with walking performance in a group of older adults. METHODS Thirty-seven older adults (mean age 78 years; 21 men and 16 women) completed an aerobic capacity (VO2 peak) test and measurement of preferred walking speed over 400 m. Maximal coupled (State 3; St3) mitochondrial respiration was determined by high-resolution respirometry in saponin-permeabilized myofibers obtained from percutanous biopsies of vastus lateralis (n = 22). Maximal phosphorylation capacity (ATPmax) of vastus lateralis was determined in vivo by (31)P magnetic resonance spectroscopy (n = 30). Quadriceps contractile volume was determined by magnetic resonance imaging. Mitochondrial efficiency (max ATP production/max O2 consumption) was characterized using ATPmax per St3 respiration (ATPmax/St3). RESULTS In vitro St3 respiration was significantly correlated with in vivo ATPmax (r (2) = .47, p = .004). Total oxidative capacity of the quadriceps (St3*quadriceps contractile volume) was a determinant of VO2 peak (r (2) = .33, p = .006). ATPmax (r (2) = .158, p = .03) and VO2 peak (r (2) = .475, p < .0001) were correlated with preferred walking speed. Inclusion of both ATPmax/St3 and VO2 peak in a multiple linear regression model improved the prediction of preferred walking speed (r (2) = .647, p < .0001), suggesting that mitochondrial efficiency is an important determinant for preferred walking speed. CONCLUSIONS Lower mitochondrial capacity and efficiency were both associated with slower walking speed within a group of older participants with a wide range of function. In addition to aerobic capacity, lower mitochondrial capacity and efficiency likely play roles in slowing gait speed with age.
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Affiliation(s)
- Paul M Coen
- Department of Health and Physical Activity, University of Pittsburgh, Trees Hall Rm 134D, Allequippa St. and Darragh St., Pittsburgh, PA 15260, USA.
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Nelson FE, Ortega JD, Conley KE. New Functional Measure of for Movement Disorder Detection, Progression and Efficacy of Intervention. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.1035.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | - Kevin E Conley
- RadiologyUniversity of WashingtonSeattleWA
- Physiology & BiophysicsUniverity of WashingtonSeattleWA
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Johannsen DL, Conley KE, Bajpeyi S, Punyanitya M, Gallagher D, Zhang Z, Covington J, Smith SR, Ravussin E. Ectopic lipid accumulation and reduced glucose tolerance in elderly adults are accompanied by altered skeletal muscle mitochondrial activity. J Clin Endocrinol Metab 2012; 97:242-50. [PMID: 22049170 PMCID: PMC3251940 DOI: 10.1210/jc.2011-1798] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
CONTEXT Aging is associated with insulin resistance and unfavorable changes in body composition including increased fat accumulation, particularly in visceral and ectopic depots. Recent studies suggest that skeletal muscle mitochondrial activity may underlie some age-associated metabolic abnormalities. OBJECTIVE Our objective was to measure mitochondrial capacity and coupling of the vastus lateralis muscle in elderly and young adults using novel in vivo approaches and relate mitochondrial activity to metabolic characteristics. DESIGN This was a cross-sectional study. PARTICIPANTS AND INTERVENTION Fourteen sedentary young (seven males and seven females, 20-34 yr of age) and 15 sedentary elderly (seven males and eight females, 70-84 yr of age) nonobese subjects selected for similar body weight underwent measures of body composition by magnetic resonance imaging and dual-energy x-ray absorptiometry, oral glucose tolerance, and in vivo mitochondrial activity by (31)P magnetic resonance and optical spectroscopy. Muscle biopsy was carried out in the same muscle to measure mitochondrial content, antioxidant activity, fiber type, and markers of mitochondrial biogenesis. RESULTS Elderly volunteers had reduced mitochondrial capacity (P = 0.05) and a trend for decreased coupling efficiency (P = 0.08) despite similar mitochondrial content and fiber type distribution. This was accompanied by greater whole-body oxidative stress (P = 0.007), less skeletal muscle mass (P < 0.001), more adipose tissue in all depots (P ≤ 0.002) except intramyocellular (P = 0.72), and lower glucose tolerance (P = 0.07). CONCLUSIONS Elderly adults show evidence of altered mitochondrial activity along with increased adiposity, oxidative stress, and reduced glucose tolerance, independent of obesity. We propose that mild uncoupling may be induced secondary to age-associated oxidative stress as a mechanism to dissipate the proton-motive force and protect against further reactive oxygen species production and damage.
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Affiliation(s)
- Darcy L Johannsen
- Pennington Biomedical Research Center, 6400 Perkins Road, Baton Rouge, Louisiana 70808, USA
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26
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Abstract
Can human muscle be highly efficient in vivo? Animal muscles typically show contraction-coupling efficiencies <50% in vitro but a recent study reports that the human first dorsal interosseous (FDI) muscle of the hand has an efficiency value in vivo of 68%. We examine two key factors that could account for this apparently high efficiency value: (1) transfer of cross-bridge work into mechanical work and (2) the use of elastic energy to do external work. Our analysis supports a high contractile efficiency reflective of nearly complete transfer of muscular to mechanical work with no contribution by recycling of elastic energy to mechanical work. Our survey of reported contraction-coupling efficiency values puts the FDI value higher than typical values found in small animals in vitro but within the range of values for human muscle in vivo. These high efficiency values support recent studies that suggest lower Ca(2+) cycling costs in working contractions and a decline in cost during repeated contractions. In the end, our analysis indicates that the FDI muscle may be exceptional in having an efficiency value on the higher end of that reported for human muscle. Thus, the FDI muscle may be an exception both in contraction-coupling efficiency and in Ca(2+) cycling costs, which makes it an ideal muscle model system offering prime conditions for studying the energetics of muscle contraction in vivo.
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Ortega J, Nelson F, Linstedt SL, Jubrias SA, Kushmerick MJ, Conley KE. An innovative apparatus for measuring in vivo efficiency of positive and negative work for human muscle studies. FASEB J 2011. [DOI: 10.1096/fasebj.25.1_supplement.1051.32] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Nelson FE, Ortega JD, Linstedt SL, Jubrias SA, Kushmerick MJ, Conley KE. Does negative work cost less. FASEB J 2011. [DOI: 10.1096/fasebj.25.1_supplement.1051.25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Marcinek DJ, Kushmerick MJ, Conley KE. Lactic acidosis in vivo: testing the link between lactate generation and H+ accumulation in ischemic mouse muscle. J Appl Physiol (1985) 2010; 108:1479-86. [PMID: 20133437 DOI: 10.1152/japplphysiol.01189.2009] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The link between lactate generation and cellular acidosis has been questioned based on the possibility of H+ generation, independent of lactate production during glycolysis under physiological conditions. Here we test whether glycolytic H+ generation matches lactate production over a physiological pH and lactate range using ischemia applied to the hindlimb of a mouse. We measured the H+ generation and ATP level in vivo using 31P-magnetic resonance spectroscopy and chemically determined intracellular lactate level in the hindlimb muscles. No significant change was found in ATP content by chemical analysis (P>0.1), in agreement with the stoichiometric decline in phosphocreatine (20.2+/-1.2 mM) vs. rise in Pi (18.7+/-2.0 mM), as measured by 31P-magnetic resonance spectroscopy. A substantial drop in pH from 7.0 to 6.7 and lactate accumulation to 25 mM were found during 25 min of ischemia. The rise in H+ generation closely agreed with the accumulation of lactate, as shown by a close correlation with a slope near identity (0.98; r2=0.86). This agreement between glycolytic H+ production and elevation of lactate is confirmed by an analysis of the underlying reactions involved in glycolysis in vivo and supports the concept of lactic acidosis under conditions that substantially elevate lactate and drop pH. However, this link is expected to fail with conditions that deplete phosphocreatine, leading to net ATP hydrolysis and nonglycolytic H+ generation. Thus both direct measurements and an analysis of the stoichiometry of glycolysis in vivo support lactate acidosis as a robust concept for physiological conditions of the muscle cell.
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Affiliation(s)
- David J Marcinek
- Department of Radiology, Box 357115, University of Washington Medical Center, Seattle, WA 98195-7115, USA
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Costford SR, Bajpeyi S, Pasarica M, Albarado DC, Thomas SC, Xie H, Church TS, Jubrias SA, Conley KE, Smith SR. Skeletal muscle NAMPT is induced by exercise in humans. Am J Physiol Endocrinol Metab 2010; 298:E117-26. [PMID: 19887595 PMCID: PMC2806106 DOI: 10.1152/ajpendo.00318.2009] [Citation(s) in RCA: 189] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
In mammals, nicotinamide phosphoribosyltransferase (NAMPT) is responsible for the first and rate-limiting step in the conversion of nicotinamide to nicotinamide adenine dinucleotide (NAD+). NAD+ is an obligate cosubstrate for mammalian sirtuin-1 (SIRT1), a deacetylase that activates peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC-1alpha), which in turn can activate mitochondrial biogenesis. Given that mitochondrial biogenesis is activated by exercise, we hypothesized that exercise would increase NAMPT expression, as a potential mechanism leading to increased mitochondrial content in muscle. A cross-sectional analysis of human subjects showed that athletes had about a twofold higher skeletal muscle NAMPT protein expression compared with sedentary obese, nonobese, and type 2 diabetic subjects (P < 0.05). NAMPT protein correlated with mitochondrial content as estimated by complex III protein content (R(2) = 0.28, P < 0.01), MRS-measured maximal ATP synthesis (R(2) = 0.37, P = 0.002), and Vo(2max) (R(2) = 0.63, P < 0.0001). In an exercise intervention study, NAMPT protein increased by 127% in sedentary nonobese subjects after 3 wk of exercise training (P < 0.01). Treatment of primary human myotubes with forskolin, a cAMP signaling pathway activator, resulted in an approximately 2.5-fold increase in NAMPT protein expression, whereas treatment with ionomycin had no effect. Activation of AMPK via AICAR resulted in an approximately 3.4-fold increase in NAMPT mRNA (P < 0.05) as well as modest increases in NAMPT protein (P < 0.05) and mitochondrial content (P < 0.05). These results demonstrate that exercise increases skeletal muscle NAMPT expression and that NAMPT correlates with mitochondrial content. Further studies are necessary to elucidate the pathways regulating NAMPT as well as its downstream effects.
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Affiliation(s)
- Sheila R Costford
- Pennington Biomedical Research Center, 6400 Perkins Rd., Baton Rouge, LA 70808, USA
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Conley KE, Jubrias SA, Cress ME, Esselman P. Mitochondrial Dysfunction Impacts Exercise Efficiency In The Elderly. Med Sci Sports Exerc 2009. [DOI: 10.1249/01.mss.0000353455.37318.9e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Villarin JJ, Conley KE, Kushmerick MJ, Marcinek DJ. Aging increases resting oxygen consumption in type‐II skeletal muscle. FASEB J 2009. [DOI: 10.1096/fasebj.23.1_supplement.954.10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Conley KE, Jubrias SA, Shankland E, Amara CE, Marcinek DJ. Does Mitochondrial Uncoupling Generate More Mitochondria in Muscle? FASEB J 2009. [DOI: 10.1096/fasebj.23.1_supplement.600.30] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Amara CE, Marcinek DJ, Shankland EG, Schenkman KA, Arakaki LSL, Conley KE. Mitochondrial function in vivo: spectroscopy provides window on cellular energetics. Methods 2008; 46:312-8. [PMID: 18930151 PMCID: PMC10798296 DOI: 10.1016/j.ymeth.2008.10.001] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2008] [Revised: 10/03/2008] [Accepted: 10/08/2008] [Indexed: 01/06/2023] Open
Abstract
Mitochondria integrate the key metabolic fluxes in the cell. This role places this organelle at the center of cellular energetics and, hence, mitochondrial dysfunction underlies a growing number of human disorders and age-related degenerative diseases. Here we present novel analytical and technical methods for evaluating mitochondrial metabolism and (dys)function in human muscle in vivo. Three innovations involving advances in optical spectroscopy (OS) and magnetic resonance spectroscopy (MRS) permit quantifying key compounds in energy metabolism to yield mitochondrial oxidation and phosphorylation fluxes. The first of these uses analytical methods applied to optical spectra to measure hemoglobin (Hb) and myoglobin (Mb) oxygenation states and relative contents ([Hb]/[Mb]) to determine mitochondrial respiration (O2 uptake) in vivo. The second uses MRS methods to quantify key high-energy compounds (creatine phosphate, PCr, and adenosine triphosphate, ATP) to determine mitochondrial phosphorylation (ATP flux) in vivo. The third involves a functional test that combines these spectroscopic approaches to determine mitochondrial energy coupling (ATP/O2), phosphorylation capacity (ATP(max)) and oxidative capacity (O2max) of muscle. These new developments in optical and MR tools allow us to determine the function and capacity of mitochondria noninvasively in order to identify specific defects in vivo that are associated with disease in human and animal muscle. The clinical implication of this unique diagnostic probe is the insight into the nature and extent of dysfunction in metabolic and degenerative disorders, as well as the ability to follow the impact of interventions designed to reverse these disorders.
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Affiliation(s)
- Catherine E. Amara
- Department of Radiology, University of Washington Medical Center, Seattle, WA 98195
| | - David J. Marcinek
- Department of Radiology, University of Washington Medical Center, Seattle, WA 98195
| | - Eric G. Shankland
- Department of Radiology, University of Washington Medical Center, Seattle, WA 98195
| | - Kenneth A. Schenkman
- Department of Bioengineering, University of Washington Medical Center, Seattle, WA 98195
- Department of Pediatrics, University of Washington Medical Center, Seattle, WA 98195
| | - Lorilee S. L. Arakaki
- Department of Pediatrics, University of Washington Medical Center, Seattle, WA 98195
| | - Kevin E. Conley
- Department of Radiology, University of Washington Medical Center, Seattle, WA 98195
- Department of Physiology & Biophysics, University of Washington Medical Center, Seattle, WA 98195
- Department of Bioengineering, University of Washington Medical Center, Seattle, WA 98195
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Abstract
PURPOSE OF REVIEW Mitochondrial dysfunction is commonly thought to result from oxidative damage that leads to defects in the electron transport chain (ETC). In this review, we highlight new research indicating that there are early changes in mitochondrial function that precede ETC defects and are reversible thereby providing the possibility of slowing the tempo of mitochondrial aging and cell death. RECENT FINDINGS Increased mitochondrial uncoupling - reduced adenosine triphosphate (ATP) produced per O2 uptake - and cell ATP depletion are evident in human muscle nearly a decade before accumulation of irreversible DNA damage that causes ETC defects. New evidence points to reduction in activators of biogenesis (e.g. PGC-1alpha) and to degradation of mitochondria allowing accumulation of molecular and membrane damage in aged mitochondria. The early dysfunction appears to be reversible based on improved mitochondrial function in vivo and elevated gene expression levels after exercise training. SUMMARY New molecular and in vivo findings regarding the onset and reversibility of mitochondrial dysfunction with age indicate the potential: 1) for diagnostic tools to identify patients at risk for severe irreversible defects later in life; and 2) of an intervention to delay the tempo of aging and improve the quality of life of the elderly.
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Affiliation(s)
- Kevin E Conley
- Department of Radiology, University of Washington Medical Center, Seattle, Washington, USA.
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Marcinek DJ, Amara CE, Matz K, Conley KE, Schenkman KA. Wavelength shift analysis: a simple method to determine the contribution of hemoglobin and myoglobin to in vivo optical spectra. Appl Spectrosc 2007; 61:665-9. [PMID: 17650380 DOI: 10.1366/000370207781269819] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The ability to quantify the contributions of hemoglobin (Hb) and myoglobin (Mb) to in vivo optical spectra has many applications for clinical and research use such as noninvasive measurement of local tissue O(2) uptake rates and regional blood content. Recent work has demonstrated an approach to independently measure oxygen saturations of Hb and Mb in optical spectra collected in vivo. However, the utility of this approach is limited without information on tissue concentrations of these species. Here we describe a strategy to quantify the contributions of Hb and Mb to in vivo optical spectra. We have found that the peak position of the deoxy-heme peak around 760 nm in the optical spectra of the deoxygenated tissue is a linear function of the relative contributions of Hb and Mb to the optical spectra. Therefore, analysis of this peak position, hereafter referred to as wavelength shift analysis, reveals the relative concentration of Hb to Mb in solutions and intact tissue. Biochemical analysis of muscle homogenates confirmed that the wavelength shift of the combined Hb/Mb peak in in vivo spectra reflects the ratio of concentrations (Hb/Mb) in muscle. The importance of quantifying the Hb contribution is illustrated by our data demonstrating that Hb accounts for approximately 80% of the optical signal in mouse skeletal muscle but only approximately 20% in human skeletal muscle. This advance will facilitate comparison of the metabolic properties between individual muscles and provides a fully noninvasive approach to measuring local respiration that can be adapted for clinical use.
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Affiliation(s)
- David J Marcinek
- Department of Radiology, University of Washington Medical Center, Seattle, Washington 98195, USA.
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Abstract
Innovative noninvasive methods open a new window on the cell in vivo. This window reveals that the tempo of mitochondrial dysfunction with age varies among muscles and in proportion to Type II muscle fiber content. Exercise training can reverse age-related dysfunction, thereby providing an intervention to slow the pace of aging and disability in the elderly.
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Affiliation(s)
- Kevin E Conley
- Department of Radiology, University of Washington Medical Center, Seattle, WA 98195-7115, USA.
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Amara CE, Shankland EG, Jubrias SA, Marcinek DJ, Kushmerick MJ, Conley KE. Mild mitochondrial uncoupling impacts cellular aging in human muscles in vivo. Proc Natl Acad Sci U S A 2007; 104:1057-62. [PMID: 17215370 PMCID: PMC1766336 DOI: 10.1073/pnas.0610131104] [Citation(s) in RCA: 168] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Faster aging is predicted in more active tissues and animals because of greater reactive oxygen species generation. Yet age-related cell loss is greater in less active cell types, such as type II muscle fibers. Mitochondrial uncoupling has been proposed as a mechanism that reduces reactive oxygen species production and could account for this paradox between longevity and activity. We distinguished these hypotheses by using innovative optical and magnetic resonance spectroscopic methods applied to noninvasively measured ATP synthesis and O(2) uptake in vivo in human muscle. Here we show that mitochondrial function is unchanged with age in mildly uncoupled tibialis anterior muscle (75% type I) despite a high respiratory rate in adults. In contrast, substantial uncoupling and loss of cellular [ATP] indicative of mitochondrial dysfunction with age was found in the lower respiring and well coupled first dorsal interosseus (43-50% type II) of the same subjects. These results reject respiration rate as the sole factor impacting the tempo of cellular aging. Instead, they support mild uncoupling as a mechanism protecting mitochondrial function and contributing to the paradoxical longevity of the most active muscle fibers.
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Affiliation(s)
| | | | | | | | - Martin J. Kushmerick
- Departments of *Radiology
- Physiology and Biophysics, and
- Bioengineering, University of Washington Medical Center, Seattle, WA 98195
| | - Kevin E. Conley
- Departments of *Radiology
- Physiology and Biophysics, and
- Bioengineering, University of Washington Medical Center, Seattle, WA 98195
- To whom correspondence should be addressed at:
Department of Radiology, Box 357115, University of Washington Medical Center, Seattle, WA 98195-7115. E-mail:
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Abstract
Mitochondrial changes are at the centre of a wide range of maladies, including diabetes, neurodegeneration and ageing-related dysfunctions. Here we describe innovative optical and magnetic resonance spectroscopic methods that non-invasively measure key mitochondrial fluxes, ATP synthesis and O(2) uptake, to permit the determination of mitochondrial coupling efficiency in vivo (P/O: half the ratio of ATP flux to O(2) uptake). Three new insights result. First, mitochondrial coupling can be measured in vivo with the rigor of a biochemical determination and provides a gold standard to define well-coupled mitochondria (P/O approximately 2.5). Second, mitochondrial coupling differs substantially among muscles in healthy adults, from values reflective of well-coupled oxidative phosphorylation in a hand muscle (P/O = 2.7) to mild uncoupling in a leg muscle (P/O = 2.0). Third, these coupling differences have an important impact on cell ageing. We found substantial uncoupling and loss of cellular [ATP] in a hand muscle indicative of mitochondrial dysfunction with age. In contrast, stable mitochondrial function was found in a leg muscle, which supports the notion that mild uncoupling is protective against mitochondrial damage with age. Thus, greater mitochondrial dysfunction is evident in muscles with higher type II muscle fibre content, which may be at the root of the preferential loss of type II fibres found in the elderly. Our results demonstrate that mitochondrial function and the tempo of ageing varies among human muscles in the same individual. These technical advances, in combination with the range of mitochondrial properties available in human muscles, provide an ideal system for studying mitochondrial function in normal tissue and the link between mitochondrial defects and cell pathology in disease.
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Affiliation(s)
- Kevin E Conley
- Department of Radiology, Box 357115, University of Washington Medical Center, Seattle, WA 98195-7115, USA.
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Conley KE. Mitochondrial Defects in Age and Disease. Med Sci Sports Exerc 2006. [DOI: 10.1249/00005768-200605001-00754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Marcinek DJ, Schenkman KA, Ciesielski WA, Lee D, Conley KE. Reduced mitochondrial coupling in vivo alters cellular energetics in aged mouse skeletal muscle. J Physiol 2005; 569:467-73. [PMID: 16254011 PMCID: PMC1464247 DOI: 10.1113/jphysiol.2005.097782] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The mitochondrial theory of ageing proposes that the accumulation of oxidative damage to mitochondria leads to mitochondrial dysfunction and tissue degeneration with age. However, no consensus has emerged regarding the effects of ageing on mitochondrial function, particularly for mitochondrial coupling (P/O). One of the main barriers to a better understanding of the effects of ageing on coupling has been the lack of in vivo approaches to measure P/O. We use optical and magnetic resonance spectroscopy to independently quantify mitochondrial ATP synthesis and O2 uptake to determine in vivo P/O. Resting ATP demand (equal to ATP synthesis) was lower in the skeletal muscle of 30-month-old C57Bl/6 mice compared to 7-month-old controls (21.9 +/- 1.5 versus 13.6 +/- 1.7 nmol ATP (g tissue)(-1) s(-1), P = 0.01). In contrast, there was no difference in the resting rates of O2 uptake between the groups (5.4 +/- 0.6 versus 8.4 +/- 1.6 nmol O2 (g tissue)(-1) s(-1)). These results indicate a nearly 50% reduction in the mitochondrial P/O in the aged animals (2.05 +/- 0.07 versus 1.05 +/- 0.36, P = 0.02). The higher resting ADP (30.8 +/- 6.8 versus 58.0 +/- 9.5 micromol g(-1), P = 0.05) and decreased energy charge (ATP/ADP) (274 +/- 70 versus 84 +/- 16, P = 0.03) in the aged mice is consistent with an impairment of oxidative ATP synthesis. Despite the reduced P/O, uncoupling protein 3 protein levels were not different in the muscles of the two groups. These results demonstrate reduced mitochondrial coupling in aged skeletal muscle that alters cellular metabolism and energetics.
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Affiliation(s)
- David J Marcinek
- Department of Radiology, University of Washington Medical Center, Seattle, WA 98195, USA.
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Amara CE, Jubrias SA, Marcinek DJ, Kushmerick MJ, Conley KE. Mitochondrial Energy Coupling (ATP/O2) In Human Muscle. Med Sci Sports Exerc 2005. [DOI: 10.1249/00005768-200505001-02355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Conley KE, Jubrias S, Cress E, Esselman P. Mitochondrial Energy Coupling (ATP/02) In Human Muscle. Med Sci Sports Exerc 2005. [DOI: 10.1249/00005768-200505001-02354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Hornberger TA, Stuppard R, Conley KE, Fedele MJ, Fiorotto ML, Chin ER, Esser KA. Mechanical stimuli regulate rapamycin-sensitive signalling by a phosphoinositide 3-kinase-, protein kinase B- and growth factor-independent mechanism. Biochem J 2004; 380:795-804. [PMID: 15030312 PMCID: PMC1224227 DOI: 10.1042/bj20040274] [Citation(s) in RCA: 193] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2004] [Revised: 03/13/2004] [Accepted: 03/19/2004] [Indexed: 11/17/2022]
Abstract
In response to growth factors, mTOR (mammalian target of rapamycin) has been identified as a central component of the signalling pathways that control the translational machinery and cell growth. Signalling through mTOR has also been shown to be necessary for the mechanical load-induced growth of cardiac and skeletal muscles. Although the mechanisms involved for mechanically induced activation of mTOR are not known, it has been suggested that activation of PI3K (phosphoinositide 3-kinase) and protein kinase B (Akt), via the release of locally acting growth factors, underlies this process. In the present study, we show that mechanically stimulating (passive stretch) the skeletal muscle ex vivo results in the activation of mTOR-dependent signalling events. The activation of mTOR-dependent signalling events was necessary for an increase in translational efficiency, demonstrating the physiological significance of this pathway. Using pharmacological inhibitors, we show that activation of mTOR-dependent signalling occurs through a PI3K-independent pathway. Consistent with these results, mechanically induced signalling through mTOR was not disrupted in muscles from Akt1-/- mice. In addition, ex vivo co-incubation experiments, along with in vitro conditioned-media experiments, demonstrate that a mechanically induced release of locally acting autocrine/paracrine growth factors was not sufficient for the activation of the mTOR pathway. Taken together, our results demonstrate that mechanical stimuli can activate the mTOR pathway independent of PI3K/Akt1 and locally acting growth factors. Thus mechanical stimuli and growth factors provide distinct inputs through which mTOR co-ordinates an increase in the translational efficiency.
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Affiliation(s)
- Troy A Hornberger
- School of Kinesiology, University of Illinois at Chicago, 901 W. Roosevelt, Chicago, IL 60608, USA
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Amara CE, Marcinek DJ, Shankland EG, Kushmerick MJ, Conley KE. Comparison of MR and Optical Spectroscopy to Measure Myoglobin Desaturation in Human FDI. Med Sci Sports Exerc 2004. [DOI: 10.1249/00005768-200405001-01540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Abstract
The coupling of mitochondrial ATP synthesis and oxygen consumption (ratio of ATP and oxygen fluxes, P/O) plays a central role in cellular bioenergetics. Reduced P/O values are associated with mitochondrial pathologies that can lead to reduced capacity for ATP synthesis and tissue degeneration. Previous work found a wide range of values for P/O in normal mitochondria. To measure mitochondrial coupling under physiological conditions, we have developed a procedure for determining the P/O of skeletal muscle in vivo. This technique measures ATPase and oxygen consumption rates during ischemia with31P magnetic resonance and optical spectroscopy, respectively. This novel approach allows the independent quantitative measurement of ATPase and oxygen flux rates in intact tissue. The quantitative measurement of oxygen consumption is made possible by our ability to independently measure the saturations of hemoglobin (Hb) and myoglobin (Mb) from optical spectra. Our results indicate that the P/O in skeletal muscle of the mouse hindlimb measured in vivo is 2.16 ± 0.24. The theoretical P/O for resting muscle is 2.33. Systemic treatment with 2,4-dinitrophenol to partially uncouple mitochondria does not affect the ATPase rate in the mouse hindlimb but nearly doubles the rate of oxygen consumption, reducing in vivo P/O to 1.37 ± 0.22. These results indicate that only a small fraction of the oxygen consumption in resting mouse skeletal muscle is nonphosphorylating under physiological conditions, suggesting that mitochondria are more tightly coupled than previously thought.
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Affiliation(s)
- David J Marcinek
- Department of Radiology, University of Washington Medical Center, Seattle, WA 98195, USA.
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Abstract
In skeletal muscle, intracellular Po2 can fall to as low as 2-3 mmHg. This study tested whether oxygen regulates cellular respiration in this range of oxygen tensions through direct coupling between phosphorylation potential and intracellular Po2. Oxygen may also behave as a simple substrate in cellular respiration that is near saturating levels over most of the physiological range. A novel optical spectroscopic method was used to measure tissue oxygen consumption (Mo2) and intracellular Po2 using the decline in hemoglobin and myoglobin saturation in the ischemic hindlimb muscle of Swiss-Webster mice. 31P magnetic resonance spectroscopic determinations yielded phosphocreatine concentration ([PCr]) and pH in the same muscle volume. Intracellular Po2 fell to <2 mmHg during the ischemic period without a change in the muscle [PCr] or pH. The constant phosphorylation state despite the decline in intracellular Po2 rejects the hypothesis that direct coupling between these two variables results in a regulatory role for oxygen in cellular respiration. A second set of experiments tested the relationship between intracellular Po2 and Mo2. In vivo Mo2 in mouse skeletal muscle was increased by systemic treatment with 2 and 4 mg/kg body wt 2,4-dinitrophenol to partially uncouple mitochondria. Mo2 was not dependent on intracellular Po2 above 3 mmHg in the three groups despite a threefold increase in Mo2. These results indicate that Mo2 and the phosphorylation state of the cell are independent of intracellular Po2 throughout the physiological range of oxygen tensions. Therefore, we reject a regulatory role for oxygen in cellular respiration and conclude that oxygen acts as a simple substrate for respiration under physiological conditions.
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Affiliation(s)
- David J Marcinek
- Department of Radiology, Box 357115, University of Washington, 1959 NE Pacific Avenue, Seattle, WA 98195-7115, USA.
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Abstract
This study tested the hypothesis that acidic pH inhibits oxidative ATP supply during exercise in hand (first dorsal interosseus, FDI) and lower limb (leg anterior compartment, LEG) muscles. We measured oxidative flux and estimated mitochondrial capacity using the changes in creatine phosphate concentration ([PCr]) and pH as detected by 31P magnetic resonance (MR) spectroscopy during isometric exercise and recovery. The highest oxidative ATP flux in sustained exercise was about half the estimated mitochondrial capacity in the LEG (0.38 +/- 0.06 vs. 0.90 +/- 0.14 mM ATP s(-1), respectively), but at the estimated capacity in the FDI (0.61 +/- 0.05 vs. 0.61 +/- 0.09 mM ATP s(-1), respectively). During sustained exercise at a higher contraction rate, intracellular acidosis (pH < 6.88) prevented a rise in oxidative flux in the LEG and FDI despite significantly increased [ADP]. We tested whether oxidative flux could increase above that achieved in sustained exercise by raising [ADP] (> 0.24 mM) and avoiding acidosis using burst exercise. This exercise raised oxidative flux (0.69 +/- 0.05 mM ATP s(-1)) to nearly twice that found with sustained exercise in the LEG and matched (0.65 +/- 0.11 mM ATP s(-1)) the near maximal flux seen during sustained exercise in the FDI. Thus both muscles reached their highest oxidative fluxes in the absence of acidosis. These results show that acidosis inhibits oxidative phosphorylation in vivo and can limit ATP supply in exercising muscle to below the mitochondrial capacity.
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Affiliation(s)
- Sharon A Jubrias
- Department of Radiology, University of Washington Medical Center, Seattle, WA 98195, USA
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Abstract
A previously published mammalian kinetic model of skeletal muscle glycogenolysis, consisting of literature in vitro parameters, was modified by substituting mouse specific Vmax values. The model demonstrates that glycogen breakdown to lactate is under ATPase control. Our criteria to test whether in vitro parameters could reproduce in vivo dynamics was the ability of the model to fit phosphocreatine (PCr) and inorganic phosphate (Pi) dynamic NMR data from ischemic basal mouse hindlimbs and predict biochemically-assayed lactate concentrations. Fitting was accomplished by optimizing four parameters--the ATPase rate coefficient, fraction of activated glycogen phosphorylase, and the equilibrium constants of creatine kinase and adenylate kinase (due to the absence of pH in the model). The optimized parameter values were physiologically reasonable, the resultant model fit the [PCr] and [Pi] timecourses well, and the model predicted the final measured lactate concentration. This result demonstrates that additional features of in vivo enzyme binding are not necessary for quantitative description of glycogenolytic dynamics.
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Affiliation(s)
- Melissa J Lambeth
- University of Washington, Department of Bioengineering, Seattle 98195-7115, USA.
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