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Senn JR, Löliger RC, Fischer JGW, Bur F, Maushart CI, Betz MJ. Acute effect of propranolol on resting energy expenditure in hyperthyroid patients. Front Endocrinol (Lausanne) 2022; 13:1026998. [PMID: 36743920 PMCID: PMC9892445 DOI: 10.3389/fendo.2022.1026998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 12/06/2022] [Indexed: 01/20/2023] Open
Abstract
OBJECTIVE Hyperthyroidism is a common endocrine disorder which leads to higher resting energy expenditure (REE). Increased activity of brown adipose tissue (BAT) contributes to elevated REE in hyperthyroid patients. For rapid control of hyperthyroid symptoms, the non-selective β-blocker propranolol is widely used. While, long-term treatment with propranolol reduces REE it is currently unclear whether it can also acutely diminish REE. DESIGN In the present prospective interventional trial we investigated the effect of propranolol on REE in hyperthyroid patients. METHODS Nineteen patients with overt primary hyperthyroidism were recruited from the endocrine outpatient clinic. REE was measured by indirect calorimetry before and after an acute dose of 80mg propranolol and during a control period, respectively. Additionally, skin temperature was recorded at eleven predefined locations during each study visit, vital signes and heart rate (HR) were measured before and after administration of propranolol. RESULTS Mean REE decreased slightly after acute administration of 80mg propranolol (p= 0.03) from 1639 ± 307 kcal/24h to 1594 ± 283 kcal/24h. During the control visit REE did not change significantly. HR correlated significantly with the level of free T3 (R2 = 0.38, p=0.029) free T4 (R2 = 0.39, p=0.026). HR decreased 81 ± 12 bpm to 67 ± 7.6 bpm 90 minutes after oral administration of propranolol (p<0.0001). Skin temperature did not change after propranolol intake. CONCLUSIONS In hyperthyroid patients a single dose of propranolol reduced heart rate substantially but REE diminished only marginally probably due to reduced myocardial energy consumption. Our data speak against a relevant contribution of BAT to the higher REE in hyperthyroidism. CLINICAL TRIAL REGISTRATION ClinicalTrials.gov, identifier (NCT03379181).
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Affiliation(s)
- Jaël Rut Senn
- Department of Endocrinology, Diabetes and Metabolism, University Hospital Basel, Basel, Switzerland
- Faculty of Medicine, University of Basel, Basel, Switzerland
| | - Rahel Catherina Löliger
- Department of Endocrinology, Diabetes and Metabolism, University Hospital Basel, Basel, Switzerland
- Faculty of Medicine, University of Basel, Basel, Switzerland
| | - Jonas Gabriel William Fischer
- Department of Endocrinology, Diabetes and Metabolism, University Hospital Basel, Basel, Switzerland
- Faculty of Medicine, University of Basel, Basel, Switzerland
| | - Fabienne Bur
- Department of Endocrinology, Diabetes and Metabolism, University Hospital Basel, Basel, Switzerland
- Faculty of Medicine, University of Basel, Basel, Switzerland
| | - Claudia Irene Maushart
- Department of Endocrinology, Diabetes and Metabolism, University Hospital Basel, Basel, Switzerland
- Faculty of Medicine, University of Basel, Basel, Switzerland
| | - Matthias Johannes Betz
- Department of Endocrinology, Diabetes and Metabolism, University Hospital Basel, Basel, Switzerland
- *Correspondence: Matthias Johannes Betz,
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Svyatova A, Kozinenko VP, Chukanov NV, Burueva DB, Chekmenev EY, Chen YW, Hwang DW, Kovtunov KV, Koptyug IV. PHIP hyperpolarized [1- 13C]pyruvate and [1- 13C]acetate esters via PH-INEPT polarization transfer monitored by 13C NMR and MRI. Sci Rep 2021; 11:5646. [PMID: 33707497 PMCID: PMC7952547 DOI: 10.1038/s41598-021-85136-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Accepted: 02/18/2021] [Indexed: 01/31/2023] Open
Abstract
Parahydrogen-induced polarization of 13C nuclei by side-arm hydrogenation (PHIP-SAH) for [1-13C]acetate and [1-13C]pyruvate esters with application of PH-INEPT-type pulse sequences for 1H to 13C polarization transfer is reported, and its efficiency is compared with that of polarization transfer based on magnetic field cycling (MFC). The pulse-sequence transfer approach may have its merits in some applications because the entire hyperpolarization procedure is implemented directly in an NMR or MRI instrument, whereas MFC requires a controlled field variation at low magnetic fields. Optimization of the PH-INEPT-type transfer sequences resulted in 13C polarization values of 0.66 ± 0.04% and 0.19 ± 0.02% for allyl [1-13C]pyruvate and ethyl [1-13C]acetate, respectively, which is lower than the corresponding polarization levels obtained with MFC for 1H to 13C polarization transfer (3.95 ± 0.05% and 0.65 ± 0.05% for allyl [1-13C]pyruvate and ethyl [1-13C]acetate, respectively). Nevertheless, a significant 13C NMR signal enhancement with respect to thermal polarization allowed us to perform 13C MR imaging of both biologically relevant hyperpolarized molecules which can be used to produce useful contrast agents for the in vivo imaging applications.
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Affiliation(s)
- Alexandra Svyatova
- grid.419389.e0000 0001 2163 7228International Tomography Center SB RAS, 3A Institutskaya St., Novosibirsk, Russia 630090 ,grid.4605.70000000121896553Novosibirsk State University, 2 Pirogova St., Novosibirsk, Russia 630090 ,grid.418953.2Institute of Cytology and Genetics SB RAS, 10 Ac. Lavrentieva Ave., Novosibirsk, Russia 630090
| | - Vitaly P. Kozinenko
- grid.419389.e0000 0001 2163 7228International Tomography Center SB RAS, 3A Institutskaya St., Novosibirsk, Russia 630090 ,grid.4605.70000000121896553Novosibirsk State University, 2 Pirogova St., Novosibirsk, Russia 630090
| | - Nikita V. Chukanov
- grid.419389.e0000 0001 2163 7228International Tomography Center SB RAS, 3A Institutskaya St., Novosibirsk, Russia 630090 ,grid.4605.70000000121896553Novosibirsk State University, 2 Pirogova St., Novosibirsk, Russia 630090
| | - Dudari B. Burueva
- grid.419389.e0000 0001 2163 7228International Tomography Center SB RAS, 3A Institutskaya St., Novosibirsk, Russia 630090 ,grid.4605.70000000121896553Novosibirsk State University, 2 Pirogova St., Novosibirsk, Russia 630090
| | - Eduard Y. Chekmenev
- grid.254444.70000 0001 1456 7807Department of Chemistry, Wayne State University, Detroit, MI 48201 USA ,grid.254444.70000 0001 1456 7807Karmanos Cancer Institute, Wayne State University, Detroit, MI 48201 USA ,grid.254444.70000 0001 1456 7807Integrative Biosciences, Wayne State University, Detroit, MI 48201 USA ,grid.4886.20000 0001 2192 9124Russian Academy of Sciences, Moscow, Russia 119991
| | - Yu-Wen Chen
- grid.28665.3f0000 0001 2287 1366Institute of Biomedical Sciences, Academia Sinica, Taipei, 115 Taiwan (Republic of China)
| | - Dennis W. Hwang
- grid.28665.3f0000 0001 2287 1366Institute of Biomedical Sciences, Academia Sinica, Taipei, 115 Taiwan (Republic of China)
| | - Kirill V. Kovtunov
- grid.419389.e0000 0001 2163 7228International Tomography Center SB RAS, 3A Institutskaya St., Novosibirsk, Russia 630090 ,grid.4605.70000000121896553Novosibirsk State University, 2 Pirogova St., Novosibirsk, Russia 630090
| | - Igor V. Koptyug
- grid.419389.e0000 0001 2163 7228International Tomography Center SB RAS, 3A Institutskaya St., Novosibirsk, Russia 630090
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Genders AJ, Holloway GP, Bishop DJ. Are Alterations in Skeletal Muscle Mitochondria a Cause or Consequence of Insulin Resistance? Int J Mol Sci 2020; 21:ijms21186948. [PMID: 32971810 PMCID: PMC7554894 DOI: 10.3390/ijms21186948] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 09/18/2020] [Accepted: 09/18/2020] [Indexed: 12/14/2022] Open
Abstract
As a major site of glucose uptake following a meal, skeletal muscle has an important role in whole-body glucose metabolism. Evidence in humans and animal models of insulin resistance and type 2 diabetes suggests that alterations in mitochondrial characteristics accompany the development of skeletal muscle insulin resistance. However, it is unclear whether changes in mitochondrial content, respiratory function, or substrate oxidation are central to the development of insulin resistance or occur in response to insulin resistance. Thus, this review will aim to evaluate the apparent conflicting information placing mitochondria as a key organelle in the development of insulin resistance in skeletal muscle.
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Affiliation(s)
- Amanda J. Genders
- Institute for Health and Sport (iHeS), Victoria University, Melbourne 8001, Australia;
- Correspondence: ; Tel.: +61-3-9919-9556
| | - Graham P. Holloway
- Dept. Human Health and Nutritional Sciences, University of Guelph, Guelph, ON N1G 2W1, Canada;
| | - David J. Bishop
- Institute for Health and Sport (iHeS), Victoria University, Melbourne 8001, Australia;
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Goedeke L, Perry RJ, Shulman GI. Emerging Pharmacological Targets for the Treatment of Nonalcoholic Fatty Liver Disease, Insulin Resistance, and Type 2 Diabetes. Annu Rev Pharmacol Toxicol 2020; 59:65-87. [PMID: 30625285 DOI: 10.1146/annurev-pharmtox-010716-104727] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Type 2 diabetes (T2D) is characterized by persistent hyperglycemia despite hyperinsulinemia, affects more than 400 million people worldwide, and is a major cause of morbidity and mortality. Insulin resistance, of which ectopic lipid accumulation in the liver [nonalcoholic fatty liver disease (NAFLD)] and skeletal muscle is the root cause, plays a major role in the development of T2D. Although lifestyle interventions and weight loss are highly effective at reversing NAFLD and T2D, weight loss is difficult to sustain, and newer approaches aimed at treating the root cause of T2D are urgently needed. In this review, we highlight emerging pharmacological strategies aimed at improving insulin sensitivity and T2D by altering hepatic energy balance or inhibiting key enzymes involved in hepatic lipid synthesis. We also summarize recent research suggesting that liver-targeted mitochondrial uncoupling may be an attractive therapeutic approach to treat NAFLD, nonalcoholic steatohepatitis, and T2D.
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Affiliation(s)
- Leigh Goedeke
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut 06520, USA; , ,
| | - Rachel J Perry
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut 06520, USA; , , .,Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520, USA
| | - Gerald I Shulman
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut 06520, USA; , , .,Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520, USA.,Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut 06520, USA
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Izkhakov E, Vaisman N, Barnes S, Barchana M, Stern N, Keinan-Boker L. Body Composition, Resting Energy Expenditure, and Metabolic Changes in Women Diagnosed with Differentiated Thyroid Carcinoma. Thyroid 2019; 29:1044-1051. [PMID: 31088334 PMCID: PMC6707037 DOI: 10.1089/thy.2018.0483] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Background: Thyroid hormones heavily impact energy expenditure, body mass, and body composition. Their role in the state of exogenous subclinical hyperthyroidism in differentiated thyroid carcinoma (DTC) patients, however, is less well defined. The first aim of this study was to assess changes in body weight, body composition, resting energy expenditure (REE), respiratory quotient (RQ), and metabolic parameters in female DTC patients, starting from the phase of a euthyroid state before total thyroidectomy through the subsequent year after thyrotropin (TSH) suppression. The second aim was to assess the relationship between these variables and thyroid function parameters. Methods: This observational case series analyzed changes in body composition, calorimetric, and metabolic parameters of 15 DTC female patients at 5 time points: (1) at initial DTC diagnosis (euthyroid state), (2) at 2-3 weeks after thyroidectomy (hypothyroid state), (3) at 2-3 months of levothyroxine (LT4) treatment (exogenous euthyroid state), (4) after 6-9 months, and (5) after 1 year of TSH suppressive LT4 therapy (exogenous subclinical hyperthyroid state). A generalized estimating equation (GEE) analysis was performed to estimate the longitudinal correlations of the total triiodothyronine (TT3)/free thyroxine (fT4) ratio (as an independent variable) with body composition, metabolic, and calorimetric parameter changes (as dependent variables). Results: REE, REE per kilogram of lean body mass (REE/LBM), pulse, and systolic and diastolic blood pressure were significantly higher after TSH suppressive LT4 therapy. The GEE analysis revealed longitudinal negative correlations between the TT3/fT4 ratio and systolic blood pressure, fasting blood glucose, body mass index, android (abdominal wall and visceral mesentery) fat distribution, trunk, and arm fat distribution, REE, and REE/LBM. There was a positive correlation with RQ. Conclusions: REE, REE/LBM, pulse, and systolic and diastolic blood pressure were significantly higher after thyroidectomy, radioiodine and TSH suppressive therapy in female DTC patients, while no changes were observed in body weight or body composition. A lower TT3/fT4 ratio longitudinally correlated with increases in REE, REE/LBM, abdominal fat distribution, systolic blood pressure, and fasting blood glucose, as well as with decreased RQ. These findings highlight the importance of judicial balancing of the benefits and detriments of TSH suppression with subsequent decreased TT3/fT4 ratios for female DTC patients.
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Affiliation(s)
- Elena Izkhakov
- Institute of Endocrinology, Metabolism and Hypertension; Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- School of Public Health, Faculty of Social Welfare and Health Sciences, University of Haifa, Haifa, Israel
- Address correspondence to: Elena Izkhakov, MD, PhD, Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv Sourasky Medical Center, 6 Weizmann Street, Tel Aviv 64233, Israel
| | - Nachum Vaisman
- Unit of Clinical Nutrition, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Sophie Barnes
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Department of Ultrasound Division of Imaging, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Micha Barchana
- School of Public Health, Faculty of Social Welfare and Health Sciences, University of Haifa, Haifa, Israel
| | - Naftali Stern
- Institute of Endocrinology, Metabolism and Hypertension; Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Lital Keinan-Boker
- School of Public Health, Faculty of Social Welfare and Health Sciences, University of Haifa, Haifa, Israel
- National Cancer Registry, Israel Center for Disease Control, Ministry of Health, Ramat Gan, Israel
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Kim MJ, Cho SW, Choi S, Ju DL, Park DJ, Park YJ. Changes in Body Compositions and Basal Metabolic Rates during Treatment of Graves' Disease. Int J Endocrinol 2018; 2018:9863050. [PMID: 29853888 PMCID: PMC5960571 DOI: 10.1155/2018/9863050] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 03/13/2018] [Accepted: 04/03/2018] [Indexed: 12/15/2022] Open
Abstract
OBJECTIVES Because thyroid hormone is an important determinant of body weight and basal metabolic rate, we investigated the changes in the basal metabolic rate and body composition sequentially after treatment for Graves' disease. METHODS A prospective cohort study was performed with six women newly diagnosed with Graves' disease. During a 52-week treatment of methimazole, body composition, resting respiratory expenditure (REE), and handgrip strength were measured consecutively. RESULTS After methimazole treatment, body weight was initially increased (0-8 weeks), subsequently plateaued (8-24 weeks), and gradually decreased in the later period (24-52 weeks) despite the decreased food intake. The measured REE was 40% higher than the predicted REE at baseline, and it gradually decreased after treatment. REE positively correlated with thyroid hormone levels, peripheral deiodinase activity, and thyroid's secretory capacity. Body compositional analyses showed that the fat mass increased during an earlier period (4-12 weeks), while the lean mass increased significantly during the later period (26-52 weeks). Consistent with the lean mass changes, muscle strength also significantly increased during the later period. CONCLUSIONS Treatment of Graves' disease increased body weight and fat mass transiently with decreased REE. However, long-term compositional changes moved in a beneficial direction increasing lean mass and reinforcing muscle strength, following decreasing fat percentages.
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Affiliation(s)
- Min Joo Kim
- Department of Internal Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | - Sun Wook Cho
- Department of Internal Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | - Sumin Choi
- Department of Food Service and Nutrition Care, Seoul National University Hospital, Seoul, Republic of Korea
| | - Dal Lae Ju
- Department of Food Service and Nutrition Care, Seoul National University Hospital, Seoul, Republic of Korea
| | - Do Joon Park
- Department of Internal Medicine, Seoul National University Hospital, Seoul, Republic of Korea
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Young Joo Park
- Department of Internal Medicine, Seoul National University Hospital, Seoul, Republic of Korea
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
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Abstract
Cardiovascular disease is the leading cause of death in general population. Besides well-known risk factors such as hypertension, impaired glucose tolerance and dyslipidemia, growing evidence suggests that hormonal changes in various endocrine diseases also impact the cardiac morphology and function. Recent studies highlight the importance of ectopic intracellular myocardial and pericardial lipid deposition, since even slight changes of these fat depots are associated with alterations in cardiac performance. In this review, we overview the effects of hormones, including insulin, thyroid hormones, growth hormone and cortisol, on heart function, focusing on their impact on myocardial lipid metabolism, cardiac substrate utilization and ectopic lipid deposition, in order to highlight the important role of even subtle hormonal changes for heart function in various endocrine and metabolic diseases.
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Affiliation(s)
- Peter Wolf
- Division of Endocrinology and MetabolismDepartment of Internal Medicine III, Medical University of Vienna, Vienna, Austria
| | - Yvonne Winhofer
- Division of Endocrinology and MetabolismDepartment of Internal Medicine III, Medical University of Vienna, Vienna, Austria
| | - Martin Krššák
- Division of Endocrinology and MetabolismDepartment of Internal Medicine III, Medical University of Vienna, Vienna, Austria
- High Field MR CentreDepartment of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Michael Krebs
- Division of Endocrinology and MetabolismDepartment of Internal Medicine III, Medical University of Vienna, Vienna, Austria
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Pietzner M, Engelmann B, Kacprowski T, Golchert J, Dirk AL, Hammer E, Iwen KA, Nauck M, Wallaschofski H, Führer D, Münte TF, Friedrich N, Völker U, Homuth G, Brabant G. Plasma proteome and metabolome characterization of an experimental human thyrotoxicosis model. BMC Med 2017; 15:6. [PMID: 28065164 PMCID: PMC5220622 DOI: 10.1186/s12916-016-0770-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Accepted: 12/15/2016] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Determinations of thyrotropin (TSH) and free thyroxine (FT4) represent the gold standard in evaluation of thyroid function. To screen for novel peripheral biomarkers of thyroid function and to characterize FT4-associated physiological signatures in human plasma we used an untargeted OMICS approach in a thyrotoxicosis model. METHODS A sample of 16 healthy young men were treated with levothyroxine for 8 weeks and plasma was sampled before the intake was started as well as at two points during treatment and after its completion, respectively. Mass spectrometry-derived metabolite and protein levels were related to FT4 serum concentrations using mixed-effect linear regression models in a robust setting. To compile a molecular signature discriminating between thyrotoxicosis and euthyroidism, a random forest was trained and validated in a two-stage cross-validation procedure. RESULTS Despite the absence of obvious clinical symptoms, mass spectrometry analyses detected 65 metabolites and 63 proteins exhibiting significant associations with serum FT4. A subset of 15 molecules allowed a robust and good prediction of thyroid hormone function (AUC = 0.86) without prior information on TSH or FT4. Main FT4-associated signatures indicated increased resting energy expenditure, augmented defense against systemic oxidative stress, decreased lipoprotein particle levels, and increased levels of complement system proteins and coagulation factors. Further association findings question the reliability of kidney function assessment under hyperthyroid conditions and suggest a link between hyperthyroidism and cardiovascular diseases via increased dimethylarginine levels. CONCLUSION Our results emphasize the power of untargeted OMICs approaches to detect novel pathways of thyroid hormone action. Furthermore, beyond TSH and FT4, we demonstrated the potential of such analyses to identify new molecular signatures for diagnosis and treatment of thyroid disorders. This study was registered at the German Clinical Trials Register (DRKS) [DRKS00011275] on the 16th of November 2016.
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Affiliation(s)
- Maik Pietzner
- Institute of Clinical Chemistry and Laboratory Medicine, University Medicine Greifswald, Ferdinand-Sauerbruch-Straße, 17475 Greifswald, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Greifswald, Greifswald, Germany
| | - Beatrice Engelmann
- Department of Functional Genomics, Interfaculty Institute for Genetics and Functional Genomics, University Medicine and Ernst-Moritz-Arndt University Greifswald, Friedrich-Ludwig-Jahn-Straße 15a, D-17475 Greifswald, Germany
| | - Tim Kacprowski
- DZHK (German Centre for Cardiovascular Research), partner site Greifswald, Greifswald, Germany
- Department of Functional Genomics, Interfaculty Institute for Genetics and Functional Genomics, University Medicine and Ernst-Moritz-Arndt University Greifswald, Friedrich-Ludwig-Jahn-Straße 15a, D-17475 Greifswald, Germany
| | - Janine Golchert
- Department of Functional Genomics, Interfaculty Institute for Genetics and Functional Genomics, University Medicine and Ernst-Moritz-Arndt University Greifswald, Friedrich-Ludwig-Jahn-Straße 15a, D-17475 Greifswald, Germany
| | - Anna-Luise Dirk
- Medical Clinic I, University of Lübeck, Experimental and Clinical Endocrinology, Ratzeburger Allee 160, Zentralklinikum (Haus 40), 23538 Lübeck, Germany
| | - Elke Hammer
- DZHK (German Centre for Cardiovascular Research), partner site Greifswald, Greifswald, Germany
- Department of Functional Genomics, Interfaculty Institute for Genetics and Functional Genomics, University Medicine and Ernst-Moritz-Arndt University Greifswald, Friedrich-Ludwig-Jahn-Straße 15a, D-17475 Greifswald, Germany
| | - K. Alexander Iwen
- Medical Clinic I, University of Lübeck, Experimental and Clinical Endocrinology, Ratzeburger Allee 160, Zentralklinikum (Haus 40), 23538 Lübeck, Germany
| | - Matthias Nauck
- Institute of Clinical Chemistry and Laboratory Medicine, University Medicine Greifswald, Ferdinand-Sauerbruch-Straße, 17475 Greifswald, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Greifswald, Greifswald, Germany
| | - Henri Wallaschofski
- Institute of Clinical Chemistry and Laboratory Medicine, University Medicine Greifswald, Ferdinand-Sauerbruch-Straße, 17475 Greifswald, Germany
- Private Practice Endocrinology, Krämpferstraße 6, 99094 Erfurt, Germany
| | - Dagmar Führer
- Department of Endocrinology and Metabolism, University Hospital Essen, University Duisburg-Essen, Hufelandstraße 55, 45122 Essen, Germany
| | - Thomas F. Münte
- Department of Neurology, University of Lübeck, Ratzeburger Allee 169, 23538 Lübeck, Germany
| | - Nele Friedrich
- Institute of Clinical Chemistry and Laboratory Medicine, University Medicine Greifswald, Ferdinand-Sauerbruch-Straße, 17475 Greifswald, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Greifswald, Greifswald, Germany
- Research Centre for Prevention and Health, Glostrup University Hospital, Nordre Ringvej 57, 2600 Glostrup, Denmark
| | - Uwe Völker
- DZHK (German Centre for Cardiovascular Research), partner site Greifswald, Greifswald, Germany
- Department of Functional Genomics, Interfaculty Institute for Genetics and Functional Genomics, University Medicine and Ernst-Moritz-Arndt University Greifswald, Friedrich-Ludwig-Jahn-Straße 15a, D-17475 Greifswald, Germany
- ZIK-FunGene (Zentrum für Innovationskompetenz - Funktionelle Genomforschung), Greifswald, Germany
| | - Georg Homuth
- Department of Functional Genomics, Interfaculty Institute for Genetics and Functional Genomics, University Medicine and Ernst-Moritz-Arndt University Greifswald, Friedrich-Ludwig-Jahn-Straße 15a, D-17475 Greifswald, Germany
- ZIK-FunGene (Zentrum für Innovationskompetenz - Funktionelle Genomforschung), Greifswald, Germany
| | - Georg Brabant
- Medical Clinic I, University of Lübeck, Experimental and Clinical Endocrinology, Ratzeburger Allee 160, Zentralklinikum (Haus 40), 23538 Lübeck, Germany
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Schrauwen P, van Marken Lichtenbelt WD. Combatting type 2 diabetes by turning up the heat. Diabetologia 2016; 59:2269-2279. [PMID: 27591854 PMCID: PMC5506100 DOI: 10.1007/s00125-016-4068-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 06/22/2016] [Indexed: 12/21/2022]
Abstract
In our westernised society, the level of physical activity is low. Interventions that increase energy expenditure are generally associated with an improvement in metabolic health. Exercise and exercise training increase energy metabolism and are considered to be among the best strategies for prevention of type 2 diabetes mellitus. More recently, cold exposure has been suggested to have a therapeutic value in type 2 diabetes. At a cellular level, there is evidence that increasing the turnover of cellular substrates such as fatty acids is associated with preventive effects against lipid-induced insulin resistance. Cellular energy sensors may underlie the effects linking energy turnover with metabolic health effects. Here we review data supporting the hypothesis that increasing energy and substrate turnover has beneficial effects on insulin sensitivity and should be considered a target for the prevention and treatment of type 2 diabetes.
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Affiliation(s)
- Patrick Schrauwen
- Department of Human Biology and Human Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, P.O. BOX 616, 6200MD, Maastricht, the Netherlands.
| | - Wouter D van Marken Lichtenbelt
- Department of Human Biology and Human Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, P.O. BOX 616, 6200MD, Maastricht, the Netherlands
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Ren J, Sherry AD, Malloy CR. A simple approach to evaluate the kinetic rate constant for ATP synthesis in resting human skeletal muscle at 7 T. NMR IN BIOMEDICINE 2016; 29:1240-8. [PMID: 25943328 PMCID: PMC4673044 DOI: 10.1002/nbm.3310] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 03/25/2015] [Accepted: 03/27/2015] [Indexed: 05/11/2023]
Abstract
Inversion transfer (IT) is a well-established technique with multiple attractive features for analysis of kinetics. However, its application in measurement of ATP synthesis rate in vivo has lagged behind the more common saturation transfer (ST) techniques. One well-recognized issue with IT is the complexity of data analysis in comparison with much simpler analysis by ST. This complexity arises, in part, because the γ-ATP spin is involved in multiple chemical reactions and magnetization exchanges, whereas Pi is involved in a single reaction, Pi → γ-ATP. By considering the reactions involving γ-ATP only as a lumped constant, the rate constant for the reaction of physiological interest, kPi→γATP , can be determined. Here, we present a new IT data analysis method to evaluate kPi→γATP using data collected from resting human skeletal muscle at 7 T. The method is based on the basic Bloch-McConnell equation, which relates kPi→γATP to m˙Pi, the rate of Pi magnetization change. The kPi→γATP value is accessed from m˙Pi data by more familiar linear correlation approaches. For a group of human subjects (n = 15), the kPi→γATP value derived for resting calf muscle was 0.066 ± 0.017 s(-1) , in agreement with literature-reported values. In this study we also explored possible time-saving strategies to speed up data acquisition for kPi→γATP evaluation using simulations. The analysis indicates that it is feasible to carry out a (31) P IT experiment in about 10 min or less at 7 T with reasonable outcome in kPi→γATP variance for measurement of ATP synthesis in resting human skeletal muscle. We believe that this new IT data analysis approach will facilitate the wide acceptance of IT to evaluate ATP synthesis rate in vivo. Copyright © 2015 John Wiley & Sons, Ltd.
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Affiliation(s)
- Jimin Ren
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX75390
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - A. Dean Sherry
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX75390
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX75390
- Department of Chemistry, University of Texas at Dallas, Richardson, TX75080
| | - Craig R. Malloy
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX75390
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX75390
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX75390
- VA North Texas Health Care System, Dallas, TX75216
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11
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Pesta DH, Tsirigotis DN, Befroy DE, Caballero D, Jurczak MJ, Rahimi Y, Cline GW, Dufour S, Birkenfeld AL, Rothman DL, Carpenter TO, Insogna K, Petersen KF, Bergwitz C, Shulman GI. Hypophosphatemia promotes lower rates of muscle ATP synthesis. FASEB J 2016; 30:3378-3387. [PMID: 27338702 PMCID: PMC5024687 DOI: 10.1096/fj.201600473r] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 06/14/2016] [Indexed: 12/13/2022]
Abstract
Hypophosphatemia can lead to muscle weakness and respiratory and heart failure, but the mechanism is unknown. To address this question, we noninvasively assessed rates of muscle ATP synthesis in hypophosphatemic mice by using in vivo saturation transfer [31P]-magnetic resonance spectroscopy. By using this approach, we found that basal and insulin-stimulated rates of muscle ATP synthetic flux (VATP) and plasma inorganic phosphate (Pi) were reduced by 50% in mice with diet-induced hypophosphatemia as well as in sodium-dependent Pi transporter solute carrier family 34, member 1 (NaPi2a)-knockout (NaPi2a-/-) mice compared with their wild-type littermate controls. Rates of VATP normalized in both hypophosphatemic groups after restoring plasma Pi concentrations. Furthermore, VATP was directly related to cellular and mitochondrial Pi uptake in L6 and RC13 rodent myocytes and isolated muscle mitochondria. Similar findings were observed in a patient with chronic hypophosphatemia as a result of a mutation in SLC34A3 who had a 50% reduction in both serum Pi content and muscle VATP After oral Pi repletion and normalization of serum Pi levels, muscle VATP completely normalized in the patient. Taken together, these data support the hypothesis that decreased muscle ATP synthesis, in part, may be caused by low blood Pi concentrations, which may explain some aspects of muscle weakness observed in patients with hypophosphatemia.-Pesta, D. H., Tsirigotis, D. N., Befroy, D. E., Caballero, D., Jurczak, M. J., Rahimi, Y., Cline, G. W., Dufour, S., Birkenfeld, A. L., Rothman, D. L., Carpenter, T. O., Insogna, K., Petersen, K. F., Bergwitz, C., Shulman, G. I. Hypophosphatemia promotes lower rates of muscle ATP synthesis.
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Affiliation(s)
- Dominik H Pesta
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Dimitrios N Tsirigotis
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Douglas E Befroy
- Department of Radiology and Biomedical Engineering, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Daniel Caballero
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Michael J Jurczak
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Yasmeen Rahimi
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Gary W Cline
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Sylvie Dufour
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Andreas L Birkenfeld
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Douglas L Rothman
- Department of Radiology and Biomedical Engineering, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Thomas O Carpenter
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut, USA; and
| | - Karl Insogna
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Kitt Falk Petersen
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA; Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Clemens Bergwitz
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Gerald I Shulman
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA; Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut, USA; Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut, USA; Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
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12
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Samuels MH, Kolobova I, Smeraglio A, Peters D, Purnell JQ, Schuff KG. Effects of Levothyroxine Replacement or Suppressive Therapy on Energy Expenditure and Body Composition. Thyroid 2016; 26:347-55. [PMID: 26700485 PMCID: PMC4790206 DOI: 10.1089/thy.2015.0345] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Thyrotropin (TSH)-suppressive doses of levothyroxine (LT4) have adverse effects on bone and cardiac function, but it is unclear whether metabolic function is also affected. The objective of this study was to determine whether women receiving TSH-suppressive LT4 doses have alterations in energy expenditure or body composition. METHODS This study was a cross-sectional comparison between three groups of women: 26 women receiving chronic TSH-suppressive LT4 doses, 80 women receiving chronic replacement LT4 doses, and 16 untreated euthyroid control women. Subjects underwent measurements of resting energy expenditure (REE), substrate oxidation, and thermic effect of food by indirect calorimetry; physical activity energy expenditure by accelerometer; caloric intake by 24-hour diet recall; and body composition by dual X-ray absorptiometry. RESULTS REE per kilogram lean body mass in the LT4 euthyroid women was 6% lower than that of the LT4-suppressed group, and 4% lower than that of the healthy control group (p = 0.04). Free triiodothyronine (fT3) levels were directly correlated with REE, and were 10% lower in the LT4 euthyroid women compared with the other two groups (p = 0.007). The groups of subjects did not differ in other measures of energy expenditure, caloric intake, or body composition. CONCLUSIONS LT4 suppression therapy does not adversely affect energy expenditure or body composition in women. However, LT4 replacement therapy is associated with a lower REE, despite TSH levels within the reference range. This may be due to lower fT3 levels, suggesting relative tissue hypothyroidism may contribute to impaired energy expenditure in LT4 therapy.
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Affiliation(s)
- Mary H. Samuels
- Division of Endocrinology, Diabetes, and Clinical Nutrition, Oregon Health and Science University, Portland, Oregon
| | - Irina Kolobova
- Division of Endocrinology, Diabetes, and Clinical Nutrition, Oregon Health and Science University, Portland, Oregon
| | - Anne Smeraglio
- Department of Internal Medicine, Stanford University School of Medicine, Stanford, California
| | - Dawn Peters
- Division of Biostatistics, Oregon Health and Science University, Portland, Oregon
| | - Jonathan Q. Purnell
- Division of Endocrinology, Diabetes, and Clinical Nutrition, Oregon Health and Science University, Portland, Oregon
| | - Kathryn G. Schuff
- Division of Endocrinology, Diabetes, and Clinical Nutrition, Oregon Health and Science University, Portland, Oregon
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13
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Tušek Jelenc M, Chmelík M, Bogner W, Krššák M, Trattnig S, Valkovič L. Feasibility and repeatability of localized (31) P-MRS four-angle saturation transfer (FAST) of the human gastrocnemius muscle using a surface coil at 7 T. NMR IN BIOMEDICINE 2016; 29:57-65. [PMID: 26684051 PMCID: PMC4833172 DOI: 10.1002/nbm.3445] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 09/28/2015] [Accepted: 10/20/2015] [Indexed: 05/11/2023]
Abstract
Phosphorus ((31) P) MRS, combined with saturation transfer (ST), provides non-invasive insight into muscle energy metabolism. However, even at 7 T, the standard ST method with T1 (app) measured by inversion recovery takes about 10 min, making it impractical for dynamic examinations. An alternative method, i.e. four-angle saturation transfer (FAST), can shorten the examination time. The aim of this study was to test the feasibility, repeatability, and possible time resolution of the localized FAST technique measurement on an ultra-high-field MR system, to accelerate the measurement of both Pi -to-ATP and PCr-to-ATP reaction rates in the human gastrocnemius muscle and to test the feasibility of using the FAST method for dynamic measurements. We measured the exchange rates and metabolic fluxes in the gastrocnemius muscle of eight healthy subjects at 7 T with the depth-resolved surface coil MRS (DRESS)-localized FAST method. For comparison, a standard ST localized method was also used. The measurement time for the localized FAST experiment was 3.5 min compared with the 10 min for the standard localized ST experiment. In addition, in five healthy volunteers, Pi -to-ATP and PCr-to-ATP metabolic fluxes were measured in the gastrocnemius muscle at rest and during plantar flexion by the DRESS-localized FAST method. The repeatability of PCr-to-ATP and Pi -to-ATP exchange rate constants, determined by the slab-selective localized FAST method at 7 T, is high, as the coefficients of variation remained below 20%, and the results of the exchange rates measured with the FAST method are comparable to those measured with standard ST. During physical activity, the PCr-to-ATP metabolic flux decreased (from FCK = 8.21 ± 1.15 mM s(-1) to FCK = 3.86 ± 1.38 mM s(-1) ) and the Pi -to-ATP flux increased (from FATP = 0.43 ± 0.14 mM s(-1) to FATP = 0.74 ± 0.13 mM s(-1) ). In conclusion, we could demonstrate that measurements in the gastrocnemius muscle are feasible at rest and are short enough to be used during exercise with the DRESS-localized FAST method at 7 T.
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Affiliation(s)
- Marjeta Tušek Jelenc
- High Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
- Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria
| | - Marek Chmelík
- High Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
- Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria
| | - Wolfgang Bogner
- High Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
- Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria
| | - Martin Krššák
- High Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
- Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria
- Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
| | - Siegfried Trattnig
- High Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
- Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria
| | - Ladislav Valkovič
- High Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
- Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria
- Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia
- Oxford Centre for Clinical MR Research (OCMR), University of Oxford, United Kingdom
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14
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Ren J, Sherry AD, Malloy CR. Amplification of the effects of magnetization exchange by (31) P band inversion for measuring adenosine triphosphate synthesis rates in human skeletal muscle. Magn Reson Med 2015; 74:1505-14. [PMID: 25469992 PMCID: PMC4792267 DOI: 10.1002/mrm.25514] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Revised: 09/23/2014] [Accepted: 10/09/2014] [Indexed: 01/06/2023]
Abstract
PURPOSE The goal of this study was to amplify the effects of magnetization exchange between γ-adenosine triphosphate (ATP) and inorganic phosphate (Pi) for evaluation of ATP synthesis rates in human skeletal muscle. METHODS The strategy works by simultaneously inverting the (31) P resonances of phosphocreatine (PCr) and ATP using a wide bandwidth, adiabatic inversion radiofrequency pulse followed by observing dynamic changes in intensity of the noninverted Pi signal versus the delay time between the inversion and observation pulses. This band inversion technique significantly delays recovery of γ-ATP magnetization; consequently, the exchange reaction, Pi ↔ γ-ATP, is readily detected and easily analyzed. RESULTS The ATP synthesis rate measured from high-quality spectral data using this method was 0.073 ± 0.011 s(-1) in resting human skeletal muscle (N = 10). The T1 of Pi was 6.93 ± 1.90 s, consistent with the intrinsic T1 of Pi at this field. The apparent T1 of γ-ATP was 4.07 ± 0.32 s, about two-fold longer than its intrinsic T1 due to storage of magnetization in PCr. CONCLUSION Band inversion provides an effective method to amplify the effects of magnetization transfer between γ-ATP and Pi. The resulting data can be easily analyzed to obtain the ATP synthesis rate using a two-site exchange model.
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Affiliation(s)
- Jimin Ren
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX75390
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - A. Dean Sherry
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX75390
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX75390
- Department of Chemistry, University of Texas at Dallas, Richardson, TX75080
| | - Craig R. Malloy
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX75390
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX75390
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX75390
- VA North Texas Health Care System, Dallas, TX75216
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15
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Lombardi A, Moreno M, de Lange P, Iossa S, Busiello RA, Goglia F. Regulation of skeletal muscle mitochondrial activity by thyroid hormones: focus on the "old" triiodothyronine and the "emerging" 3,5-diiodothyronine. Front Physiol 2015; 6:237. [PMID: 26347660 PMCID: PMC4543916 DOI: 10.3389/fphys.2015.00237] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 08/07/2015] [Indexed: 11/20/2022] Open
Abstract
3,5,3′-Triiodo-L-thyronine (T3) plays a crucial role in regulating metabolic rate and fuel oxidation; however, the mechanisms by which it affects whole-body energy metabolism are still not completely understood. Skeletal muscle (SKM) plays a relevant role in energy metabolism and responds to thyroid state by remodeling the metabolic characteristics and cytoarchitecture of myocytes. These processes are coordinated with changes in mitochondrial content, bioenergetics, substrate oxidation rate, and oxidative phosphorylation efficiency. Recent data indicate that “emerging” iodothyronines have biological activity. Among these, 3,5-diiodo-L-thyronine (T2) affects energy metabolism, SKM substrate utilization, and mitochondrial functionality. The effects it exerts on SKM mitochondria involve more aspects of mitochondrial bioenergetics; among these, respiratory chain activity, mitochondrial thermogenesis, and lipid-handling are stimulated rapidly. This mini review focuses on signaling and biochemical pathways activated by T3 and T2 in SKM that influence the above processes. These novel aspects of thyroid physiology could reveal new perspectives for understanding the involvement of SKM mitochondria in hypo- and hyper-thyroidism.
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Affiliation(s)
- Assunta Lombardi
- Department of Biology, University of Naples Federico II Naples, Italy
| | - Maria Moreno
- Department of Science and Technology, University of Sannio Benevento, Italy
| | - Pieter de Lange
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, Second University of Naples Caserta, Italy
| | - Susanna Iossa
- Department of Biology, University of Naples Federico II Naples, Italy
| | - Rosa A Busiello
- Department of Science and Technology, University of Sannio Benevento, Italy
| | - Fernando Goglia
- Department of Science and Technology, University of Sannio Benevento, Italy
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16
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Kim DH, Choi DH, Kim HW, Choi SW, Kim BB, Chung JW, Koh YY, Chang KS, Hong SP. Prediction of infarct severity from triiodothyronine levels in patients with ST-elevation myocardial infarction. Korean J Intern Med 2014; 29:454-65. [PMID: 25045293 PMCID: PMC4101592 DOI: 10.3904/kjim.2014.29.4.454] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 09/04/2013] [Accepted: 10/28/2013] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND/AIMS The aim of the present study was to evaluate the relationship between thyroid hormone levels and infarct severity in patients with ST-elevation myocardial infarction (STEMI). METHODS We retrospectively reviewed thyroid hormone levels, infarct severity, and the extent of transmurality in 40 STEMI patients evaluated via contrast-enhanced cardiac magnetic resonance imaging. RESULTS The high triiodothyronine (T3) group (≥ 68.3 ng/dL) exhibited a significantly higher extent of transmural involvement (late transmural enhancement > 75% after administration of gadolinium contrast agent) than did the low T3 group (60% vs. 15%; p = 0.003). However, no significant difference was evident between the high- and low-thyroid-stimulating hormone/free thyroxine (FT4) groups. When the T3 cutoff level was set to 68.3 ng/dL using a receiver operating characteristic curve, the sensitivity was 80% and the specificity 68% in terms of differentiating between those with and without transmural involvement. Upon logistic regression analysis, high T3 level was an independent predictor of transmural involvement after adjustment for the presence of diabetes mellitus (DM) and the use of glycoprotein IIb/IIIa inhibitors (odds ratio, 40.62; 95% confidence interval, 3.29 to 502; p = 0.004). CONCLUSIONS The T3 level predicted transmural involvement that was independent of glycoprotein IIb/IIIa inhibitor use and DM positivity.
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Affiliation(s)
- Dong Hun Kim
- Department of Radiology, Chosun University School of Medicine, Gwangju, Korea
| | - Dong-Hyun Choi
- Department of Internal Medicine, Chosun University School of Medicine, Gwangju, Korea
| | - Hyun-Wook Kim
- Department of Internal Medicine, Chosun University School of Medicine, Gwangju, Korea
| | - Seo-Won Choi
- Department of Internal Medicine, Chosun University School of Medicine, Gwangju, Korea
| | - Bo-Bae Kim
- Department of Internal Medicine, Chosun University School of Medicine, Gwangju, Korea
| | - Joong-Wha Chung
- Department of Internal Medicine, Chosun University School of Medicine, Gwangju, Korea
| | - Young-Youp Koh
- Department of Internal Medicine, Chosun University School of Medicine, Gwangju, Korea
| | - Kyong-Sig Chang
- Department of Internal Medicine, Chosun University School of Medicine, Gwangju, Korea
| | - Soon-Pyo Hong
- Department of Internal Medicine, Chosun University School of Medicine, Gwangju, Korea
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17
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Ren J, Yang B, Sherry AD, Malloy CR. Exchange kinetics by inversion transfer: integrated analysis of the phosphorus metabolite kinetic exchanges in resting human skeletal muscle at 7 T. Magn Reson Med 2014; 73:1359-69. [PMID: 24733433 DOI: 10.1002/mrm.25256] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 03/06/2014] [Accepted: 03/26/2014] [Indexed: 01/06/2023]
Abstract
PURPOSE To develop an inversion pulse-based, chemical exchange saturation transfer-like method for detection of (31) P magnetization exchanges among all nuclear magnetic resonance visible metabolites suitable for providing an integrated kinetic analysis of phosphorus exchange reactions in vivo. METHODS The exchange kinetics by inversion transfer (EKIT) sequence includes application of a frequency-selective inversion pulse arrayed over the range of relevant (31) P frequencies, followed by a constant delay and a hard readout pulse. A series of EKIT spectra, each given by a plot of Z-magnetization for each metabolite of interest versus frequency of the inversion pulse, can be generated from this single data set. RESULTS EKIT spectra reflect chemical exchange due to known biochemical reactions, cross-relaxation effects, and relayed magnetization transfers due to both processes. The rate constants derived from EKIT data collected on resting human skeletal muscle were: ATP synthesis via ATP synthase (0.050 ± 0.016 s(-1) ), ATP synthesis via creatine kinase (0.264 ± 0.023 s(-1) ), and cross-relaxation between neighboring spin pairs within ATP (0.164 ± 0.022 s(-1) ). CONCLUSION EKIT provides a simple, alternative method to detect chemical exchange, cross relaxation, and relayed magnetization transfer effects in human skeletal muscle at 7 T.
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Affiliation(s)
- Jimin Ren
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA; Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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18
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Salvatore D, Simonides WS, Dentice M, Zavacki AM, Larsen PR. Thyroid hormones and skeletal muscle--new insights and potential implications. Nat Rev Endocrinol 2014; 10:206-14. [PMID: 24322650 PMCID: PMC4037849 DOI: 10.1038/nrendo.2013.238] [Citation(s) in RCA: 215] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Thyroid hormone signalling regulates crucial biological functions, including energy expenditure, thermogenesis, development and growth. The skeletal muscle is a major target of thyroid hormone signalling. The type 2 and 3 iodothyronine deiodinases (DIO2 and DIO3, respectively) have been identified in skeletal muscle. DIO2 expression is tightly regulated and catalyses outer-ring monodeiodination of the secreted prohormone tetraiodothyronine (T4) to generate the active hormone tri-iodothyronine (T3). T3 can remain in the myocyte to signal through nuclear receptors or exit the cell to mix with the extracellular pool. By contrast, DIO3 inactivates T3 through removal of an inner-ring iodine. Regulation of the expression and activity of deiodinases constitutes a cell-autonomous, pre-receptor mechanism for controlling the intracellular concentration of T3. This local control of T3 activity is crucial during the various phases of myogenesis. Here, we review the roles of T3 in skeletal muscle development and homeostasis, with a focus on the emerging local deiodinase-mediated control of T3 signalling. Moreover, we discuss these novel findings in the context of both muscle homeostasis and pathology, and examine how skeletal muscle deiodinase activity might be therapeutically harnessed to improve satellite-cell-mediated muscle repair in patients with skeletal muscle disorders, muscle atrophy or injury.
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Affiliation(s)
- Domenico Salvatore
- Department of Clinical Medicine and Surgery, University of Naples 'Federico II', Building 1, 1st floor, Via Pansini 5, 80131 Naples, Italy
| | - Warner S Simonides
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Centre, van der Boechorststraat 7, 1081 BT, Amsterdam, Netherlands
| | - Monica Dentice
- Department of Clinical Medicine and Surgery, University of Naples 'Federico II', Building 1, 1st floor, Via Pansini 5, 80131 Naples, Italy
| | - Ann Marie Zavacki
- Thyroid Section, Division of Endocrinology, Diabetes, and Hypertension, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, 77 Avenue Louis Pasteur, HIM room 641, Boston, MA 02115, USA
| | - P Reed Larsen
- Thyroid Section, Division of Endocrinology, Diabetes, and Hypertension, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, 77 Avenue Louis Pasteur, HIM room 641, Boston, MA 02115, USA
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19
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Befroy DE, Perry RJ, Jain N, Dufour S, Cline GW, Trimmer JK, Brosnan J, Rothman DL, Petersen KF, Shulman GI. Direct assessment of hepatic mitochondrial oxidative and anaplerotic fluxes in humans using dynamic 13C magnetic resonance spectroscopy. Nat Med 2014; 20:98-102. [PMID: 24317120 PMCID: PMC3947269 DOI: 10.1038/nm.3415] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 10/29/2013] [Indexed: 12/11/2022]
Abstract
Despite the central role of the liver in the regulation of glucose and lipid metabolism, there are currently no methods to directly assess hepatic oxidative metabolism in humans in vivo. By using a new (13)C-labeling strategy in combination with (13)C magnetic resonance spectroscopy, we show that rates of mitochondrial oxidation and anaplerosis in human liver can be directly determined noninvasively. Using this approach, we found the mean rates of hepatic tricarboxylic acid (TCA) cycle flux (VTCA) and anaplerotic flux (VANA) to be 0.43 ± 0.04 μmol g(-1) min(-1) and 0.60 ± 0.11 μmol g(-1) min(-1), respectively, in twelve healthy, lean individuals. We also found the VANA/VTCA ratio to be 1.39 ± 0.22, which is severalfold lower than recently published estimates using an indirect approach. This method will be useful for understanding the pathogenesis of nonalcoholic fatty liver disease and type 2 diabetes, as well as for assessing the effectiveness of new therapies targeting these pathways in humans.
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Affiliation(s)
- Douglas E Befroy
- 1] Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut, USA. [2] Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA. [3]
| | - Rachel J Perry
- 1] Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA. [2] Department of Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut, USA. [3]
| | - Nimit Jain
- Department of Biomedical Engineering, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Sylvie Dufour
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Gary W Cline
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | | | | | - Douglas L Rothman
- 1] Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut, USA. [2] Department of Biomedical Engineering, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Kitt Falk Petersen
- 1] Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA. [2] Novo Nordisk Foundation Center for Basic Metabolic Research, Copenhagen, Denmark
| | - Gerald I Shulman
- 1] Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA. [2] Department of Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut, USA. [3] Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut, USA. [4] Novo Nordisk Foundation Center for Basic Metabolic Research, Copenhagen, Denmark
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20
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Kurdiova T, Balaz M, Vician M, Maderova D, Vlcek M, Valkovic L, Srbecky M, Imrich R, Kyselovicova O, Belan V, Jelok I, Wolfrum C, Klimes I, Krssak M, Zemkova E, Gasperikova D, Ukropec J, Ukropcova B. Effects of obesity, diabetes and exercise on Fndc5 gene expression and irisin release in human skeletal muscle and adipose tissue: in vivo and in vitro studies. J Physiol 2013; 592:1091-107. [PMID: 24297848 DOI: 10.1113/jphysiol.2013.264655] [Citation(s) in RCA: 277] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Irisin was identified as a myokine secreted by contracting skeletal muscle, possibly mediating some exercise health benefits via 'browning' of white adipose tissue. However, a controversy exists concerning irisin origin, regulation and function in humans. Thus, we have explored Fndc5 gene and irisin protein in two clinical studies: (i) a cross-sectional study (effects of type 2 diabetes (T2D) in drug-naive men) and (ii) an intervention study (exercise effects in sedentary, overweight/obese individuals). Glucose tolerance and insulin sensitivity were assessed. Maximal aerobic capacity and muscle strength were measured before and after training. Body composition (magnetic resonance imaging), muscle and liver fat content (1H-magnetic resonance spectroscopy (MRS)) and in vivo muscle metabolism (32P-MRS) were determined. Skeletal muscle and subcutaneous abdominal adipose tissue samples were taken in the fasted state and during euglycaemic hyperinsulinaemia (adipose tissue) and before/after exercise training (muscle). We found that muscle Fndc5 mRNA was increased in prediabetes but not T2D. Fndc5 in adipose tissue and irisin in plasma were reduced in T2D by 40% and 50%, respectively. In contrast, T2D-derived myotubes expressed/secreted the highest levels of Fndc5/irisin. Neither hyperinsulinaemia (adipose tissue/plasma) nor exercise (muscle/plasma) affected Fndc5/irisin in vivo. Circulating irisin was positively associated with muscle mass, strength and metabolism and negatively with fasting glycaemia. Glucose and palmitate decreased Fndc5 mRNA in myotubes in vitro. We conclude that distinct patterns of Fndc5/irisin in muscle, adipose tissue and circulation, and concordant in vivo down-regulation in T2D, indicate that irisin might distinguish metabolic health and disease. Moreover, Fndc5/irisin was discordantly regulated in diabetic muscle and myotubes in vitro, suggesting that whole body factors, such as glucose and fatty acids, might be important for irisin regulation. Exercise did not affect Fndc5/irisin. However, irisin was positively linked to muscle mass, strength and metabolism, pointing to common regulatory factors and/or the potential for irisin to modify muscle phenotype.
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Affiliation(s)
- Timea Kurdiova
- Obesity Section, Laboratory of Diabetes and Metabolic Disease, Institute of Experimental Endocrinology, Slovak Academy of Sciences, Vlarska 3, 83306 Bratislava, Slovak Republic.
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21
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Befroy DE, Rothman DL, Petersen KF, Shulman GI. ³¹P-magnetization transfer magnetic resonance spectroscopy measurements of in vivo metabolism. Diabetes 2012; 61:2669-78. [PMID: 23093656 PMCID: PMC3478545 DOI: 10.2337/db12-0558] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Magnetic resonance spectroscopy offers a broad range of noninvasive analytical methods for investigating metabolism in vivo. Of these, the magnetization-transfer (MT) techniques permit the estimation of the unidirectional fluxes associated with metabolic exchange reactions. Phosphorus (³¹P) MT measurements can be used to examine the bioenergetic reactions of the creatine-kinase system and the ATP synthesis/hydrolysis cycle. Observations from our group and others suggest that the inorganic phosphate (P(i)) → ATP flux in skeletal muscle may be modulated by certain conditions, including aging, insulin resistance, and diabetes, and may reflect inherent alterations in mitochondrial metabolism. However, such effects on the P(i) → ATP flux are not universally observed under conditions in which mitochondrial function, assessed by other techniques, is impaired, and recent articles have raised concerns about the absolute magnitude of the measured reaction rates. As the application of ³¹P-MT techniques becomes more widespread, this article reviews the methodology and outlines our experience with its implementation in a variety of models in vivo. Also discussed are potential limitations of the technique, complementary methods for assessing oxidative metabolism, and whether the P(i) → ATP flux is a viable biomarker of metabolic function in vivo.
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Affiliation(s)
- Douglas E Befroy
- Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, CT, USA.
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22
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Abstract
Magnetic resonance spectroscopy (MRS) methods offer a potentially valuable window into cellular metabolism. Measurement of flux between inorganic phosphate (Pi) and ATP using (31)P MRS magnetization transfer has been used in resting muscle to assess what is claimed to be mitochondrial ATP synthesis and has been particularly popular in the study of insulin effects and insulin resistance. However, the measured Pi→ATP flux in resting skeletal muscle is far higher than the true rate of oxidative ATP synthesis, being dominated by a glycolytically mediated Pi↔ATP exchange reaction that is unrelated to mitochondrial function. Furthermore, even if measured accurately, the ATP production rate in resting muscle has no simple relationship to mitochondrial capacity as measured either ex vivo or in vivo. We summarize the published measurements of Pi→ATP flux, concentrating on work relevant to diabetes and insulin, relate it to current understanding of the physiology of mitochondrial ATP synthesis and glycolytic Pi↔ATP exchange, and discuss some possible implications of recently reported correlations between Pi→ATP flux and other physiological measures.
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Affiliation(s)
- Graham J Kemp
- Department of Musculoskeletal Biology and Magnetic Resonance and Image Analysis Research Centre, University of Liverpool, Liverpool, UK.
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23
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Johannsen DL, Galgani JE, Johannsen NM, Zhang Z, Covington JD, Ravussin E. Effect of short-term thyroxine administration on energy metabolism and mitochondrial efficiency in humans. PLoS One 2012; 7:e40837. [PMID: 22844412 PMCID: PMC3406028 DOI: 10.1371/journal.pone.0040837] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Accepted: 06/16/2012] [Indexed: 11/28/2022] Open
Abstract
The physiologic effects of triiodothyronine (T3) on metabolic rate are well-documented; however, the effects of thyroxine (T4) are less clear despite its wide-spread use to treat thyroid-related disorders and other non-thyroidal conditions. Here, we investigated the effects of acute (3-day) T4 supplementation on energy expenditure at rest and during incremental exercise. Furthermore, we used a combination of in situ and in vitro approaches to measure skeletal muscle metabolism before and after T4 treatment. Ten healthy, euthyroid males were given 200 µg T4 (levothyroxine) per day for 3 days. Energy expenditure was measured at rest and during exercise by indirect calorimetry, and skeletal muscle mitochondrial function was assessed by in situ ATP flux (31P MRS) and in vitro respiratory control ratio (RCR, state 3/state 4 rate of oxygen uptake using a Clark-type electrode) before and after acute T4 treatment. Thyroxine had a subtle effect on resting metabolic rate, increasing it by 4% (p = 0.059) without a change in resting ATP demand (i.e., ATP flux) of the vastus lateralis. Exercise efficiency did not change with T4 treatment. The maximal capacity to produce ATP (state 3 respiration) and the coupled state of the mitochondria (RCR) were reduced by approximately 30% with T4 (p = 0.057 and p = 0.04, respectively). Together, the results suggest that T4, although less metabolically active than T3, reduces skeletal muscle efficiency and modestly increases resting metabolism even after short-term supplementation. Our findings may be clinically relevant given the expanding application of T4 to treat non-thyroidal conditions such as obesity and weight loss.
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Affiliation(s)
- Darcy L. Johannsen
- Pennington Biomedical Research Center, Baton Rouge, Louisiana, United States of America
| | - Jose E. Galgani
- Pennington Biomedical Research Center, Baton Rouge, Louisiana, United States of America
- Department of Nutrition, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Neil M. Johannsen
- Pennington Biomedical Research Center, Baton Rouge, Louisiana, United States of America
| | - Zhengyu Zhang
- Pennington Biomedical Research Center, Baton Rouge, Louisiana, United States of America
| | - Jeffrey D. Covington
- Pennington Biomedical Research Center, Baton Rouge, Louisiana, United States of America
| | - Eric Ravussin
- Pennington Biomedical Research Center, Baton Rouge, Louisiana, United States of America
- * E-mail:
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24
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Lim EL, Hollingsworth KG, Smith FE, Thelwall PE, Taylor R. Effects of raising muscle glycogen synthesis rate on skeletal muscle ATP turnover rate in type 2 diabetes. Am J Physiol Endocrinol Metab 2011; 301:E1155-62. [PMID: 21917633 PMCID: PMC3233777 DOI: 10.1152/ajpendo.00278.2011] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Mitochondrial dysfunction has been implicated in the pathogenesis of type 2 diabetes. We hypothesized that any impairment in insulin-stimulated muscle ATP production could merely reflect the lower rates of muscle glucose uptake and glycogen synthesis, rather than cause it. If this is correct, muscle ATP turnover rates in type 2 diabetes could be increased if glycogen synthesis rates were normalized by the mass-action effect of hyperglycemia. Isoglycemic- and hyperglycemic-hyperinsulinemic clamps were performed on type 2 diabetic subjects and matched controls, with muscle ATP turnover and glycogen synthesis rates measured using (31)P- and (13)C-magnetic resonance spectroscopy, respectively. In diabetic subjects, hyperglycemia increased muscle glycogen synthesis rates to the level observed in controls at isoglycemia [from 19 ± 9 to 41 ± 12 μmol·l(-1)·min(-1) (P = 0.012) vs. 40 ± 7 μmol·l(-1)·min(-1) in controls]. This was accompanied by a modest increase in muscle ATP turnover rates (7.1 ± 0.5 vs. 8.6 ± 0.7 μmol·l(-1)·min(-1), P = 0.04). In controls, hyperglycemia brought about a 2.5-fold increase in glycogen synthesis rates (100 ± 24 vs. 40 ± 7 μmol·l(-1)·min(-1), P = 0.028) and a 23% increase in ATP turnover rates (8.1 ± 0.9 vs. 10.0 ± 0.9 μmol·l(-1)·min(-1), P = 0.025) from basal state. Muscle ATP turnover rates correlated positively with glycogen synthesis rates (r(s) = 0.46, P = 0.005). Changing the rate of muscle glucose metabolism in type 2 diabetic subjects alters demand for ATP synthesis at rest. In type 2 diabetes, skeletal muscle ATP turnover rates reflect the rate of glucose uptake and glycogen synthesis, rather than any primary mitochondrial defect.
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Affiliation(s)
- Ee L Lim
- Institute of Cellular Medicine, Newcastle Magnetic Resonance Centre, Newcastle University, Newcastle upon Tyne, United Kingdom
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25
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Sleigh A, Raymond-Barker P, Thackray K, Porter D, Hatunic M, Vottero A, Burren C, Mitchell C, McIntyre M, Brage S, Carpenter TA, Murgatroyd PR, Brindle KM, Kemp GJ, O'Rahilly S, Semple RK, Savage DB. Mitochondrial dysfunction in patients with primary congenital insulin resistance. J Clin Invest 2011; 121:2457-61. [PMID: 21555852 PMCID: PMC3104774 DOI: 10.1172/jci46405] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Accepted: 03/23/2011] [Indexed: 01/07/2023] Open
Abstract
Mitochondrial dysfunction is associated with insulin resistance and type 2 diabetes. It has thus been suggested that primary and/or genetic abnormalities in mitochondrial function may lead to accumulation of toxic lipid species in muscle and elsewhere, impairing insulin action on glucose metabolism. Alternatively, however, defects in insulin signaling may be primary events that result in mitochondrial dysfunction, or there may be a bidirectional relationship between these phenomena. To investigate this, we examined mitochondrial function in patients with genetic defects in insulin receptor (INSR) signaling. We found that phosphocreatine recovery after exercise, a measure of skeletal muscle mitochondrial function in vivo, was significantly slowed in patients with INSR mutations compared with that in healthy age-, fitness-, and BMI-matched controls. These findings suggest that defective insulin signaling may promote mitochondrial dysfunction. Furthermore, consistent with previous studies of mouse models of mitochondrial dysfunction, basal and sleeping metabolic rates were both significantly increased in genetically insulin-resistant patients, perhaps because mitochondrial dysfunction necessitates increased nutrient oxidation in order to maintain cellular energy levels.
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Affiliation(s)
- Alison Sleigh
- Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, United Kingdom
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26
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Song Y, Yao X, Ying H. Thyroid hormone action in metabolic regulation. Protein Cell 2011; 2:358-68. [PMID: 21614672 DOI: 10.1007/s13238-011-1046-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Accepted: 04/24/2011] [Indexed: 12/19/2022] Open
Abstract
Thyroid hormone plays pivotal roles in growth, differentiation, development and metabolic homeostasis via thyroid hormone receptors (TRs) by controlling the expression of TR target genes. The transcriptional activity of TRs is modulated by multiple factors including various TR isoforms, diverse thyroid hormone response elements, different heterodimeric partners, coregulators, and the cellular location of TRs. In the present review, we summarize recent advance in understanding the molecular mechanisms of thyroid hormone action obtained from human subject research, thyroid hormone mimetics application, TR isoform-specific knock-in mouse models, and mitochondrion study with highlights in metabolic regulations. Finally, as future perspectives, we share our thoughts about current challenges and possible approaches to promote our knowledge of thyroid hormone action in metabolism.
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Affiliation(s)
- Yiyun Song
- Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai, China
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27
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From AHL, Ugurbil K. Standard magnetic resonance-based measurements of the Pi→ATP rate do not index the rate of oxidative phosphorylation in cardiac and skeletal muscles. Am J Physiol Cell Physiol 2011; 301:C1-11. [PMID: 21368294 DOI: 10.1152/ajpcell.00345.2010] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Magnetic resonance spectroscopy-based magnetization transfer techniques (MT) are commonly used to assess the rate of oxidative (i.e., mitochondrial) ATP synthesis in intact tissues. Physiologically appropriate interpretation of MT rate data depends on accurate appraisal of the biochemical events that contribute to a specific MT rate measurement. The relative contributions of the specific enzymatic reactions that can contribute to a MT P(i)→ATP rate measurement are tissue dependent; nonrecognition of this fact can bias the interpretation of MT P(i)→ATP rate data. The complexities of MT-based measurements of mitochondrial ATP synthesis rates made in striated muscle and other tissues are reviewed, following which, the adverse impacts of erroneous P(i)→ATP rate data analyses on the physiological inferences presented in selected published studies of cardiac and skeletal muscle are considered.
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Affiliation(s)
- Arthur H L From
- Center for Magnetic Resonance Research, University of Minnesota, 2021 6th Street SE, Minneapolis, MN 55455, USA.
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28
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Abstract
A decline in mitochondrial function occurs in many conditions. A report in this issue of Cell Metabolism (Larsen et al., 2011) shows that dietary inorganic nitrates enhance muscle mitochondrial efficiency. It is an attractive hypothesis that dietary changes enhance energy efficiency, but its potential application depends on long-term studies investigating net benefits versus adverse effects.
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29
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Lim EL, Hollingsworth KG, Thelwall PE, Taylor R. Measuring the acute effect of insulin infusion on ATP turnover rate in human skeletal muscle using phosphorus-31 magnetic resonance saturation transfer spectroscopy. NMR IN BIOMEDICINE 2010; 23:952-7. [PMID: 20623795 PMCID: PMC3120981 DOI: 10.1002/nbm.1519] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Accepted: 01/21/2010] [Indexed: 05/22/2023]
Abstract
Mitochondrial dysfunction has been proposed to underlie the insulin resistance of type 2 diabetes. However, the relative time course of insulin action in stimulating ATP turnover rate and glucose uptake in skeletal muscle has not been examined. These two parameters were measured in young healthy subjects using the (31)P MRS saturation transfer method in conjunction with the euglycaemic hyperinsulinaemic clamp technique respectively. Glucose infusion rate rose rapidly from 0 to 2.90 ± 0.11 mg/kg(ffm)/min during the first 10 min of insulin infusion and further to 6.17 ± 0.57 mg/kg(ffm)/min between 15 and 45 min. In contrast, baseline ATP turnover rate was 9.0 ± 0.4 µmol/g/min of muscle and did not change during the first 45 min of insulin infusion. Between 50 and 80 minutes ATP turnover rate increased by 8% and remained steady to 150 minutes (9.7 ± 0.5 µmol/g/min of muscle, p = 0.03 vs baseline). The in vivo time course of insulin stimulation of skeletal muscle ATP turnover rate is not consistent with a rate limiting effect upon the initiation of insulin-stimulated glycogen synthesis.
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Affiliation(s)
- Ee Lin Lim
- Institute of Cellular Medicine, Newcastle Magnetic Resonance Centre, Newcastle University, Newcastle upon Tyne, UK
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30
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Schär M, El-Sharkawy AMM, Weiss RG, Bottomley PA. Triple repetition time saturation transfer (TRiST) 31P spectroscopy for measuring human creatine kinase reaction kinetics. Magn Reson Med 2010; 63:1493-501. [PMID: 20512852 DOI: 10.1002/mrm.22347] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Human cardiac phosphorus MR saturation transfer experiments to quantify creatine kinase forward rate constants (k(f)) have previously been performed at 1.5 T. Such experiments could benefit from increased signal-to-noise ratio (SNR) and spectral resolution at 3 T. At 1.5 T, the four-angle saturation transfer method was applied with low-angle adiabatic pulses and surface coils. However, low-angle adiabatic pulses are potentially problematic above 1.5 T due to bandwidth limitations, power requirements, power deposition, and intrapulse spin-spin relaxation. For localized metabolite spin-lattice relaxation time (T(1)) measurements, a dual repetition time approach with adiabatic half-passage pulses was recently introduced to solve these problems at 3 T. Because the saturation transfer experiment requires a T(1) measurement performed while one reacting moiety is saturated, we adapt the dual repetition time approach to measure k(f) using a triple repetition time saturation transfer (TRiST) method. A new pulsed saturation scheme with reduced sensitivity to static magnetic field inhomogeneity and compatibility with cardiac triggering is also presented. TRiST measurements of k(f) are validated in human calf muscle against conventional saturation transfer and found to agree within 3%. The first 3-T TRiST measurements of creatine kinase k(f) in the human calf (n = 6), chest muscle, and heart (n = 8) are 0.26 +/- 0.04 s(-1), 0.23 +/- 0.03 s(-1), and 0.32 +/- 0.07 s(-1), respectively, consistent with prior 1.5 T values.
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Affiliation(s)
- Michael Schär
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA.
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31
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Abstract
Insulin resistance has long been associated with obesity. More than 40 years ago, Randle and colleagues postulated that lipids impaired insulin-stimulated glucose use by muscles through inhibition of glycolysis at key points. However, work over the past two decades has shown that lipid-induced insulin resistance in skeletal muscle stems from defects in insulin-stimulated glucose transport activity. The steatotic liver is also resistant to insulin in terms of inhibition of hepatic glucose production and stimulation of glycogen synthesis. In muscle and liver, the intracellular accumulation of lipids-namely, diacylglycerol-triggers activation of novel protein kinases C with subsequent impairments in insulin signalling. This unifying hypothesis accounts for the mechanism of insulin resistance in obesity, type 2 diabetes, lipodystrophy, and ageing; and the insulin-sensitising effects of thiazolidinediones.
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Affiliation(s)
- Varman T Samuel
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06536-8012, USA
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32
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Mitchell CS, Savage DB, Dufour S, Schoenmakers N, Murgatroyd P, Befroy D, Halsall D, Northcott S, Raymond-Barker P, Curran S, Henning E, Keogh J, Owen P, Lazarus J, Rothman DL, Farooqi IS, Shulman GI, Chatterjee K, Petersen KF. Resistance to thyroid hormone is associated with raised energy expenditure, muscle mitochondrial uncoupling, and hyperphagia. J Clin Invest 2010; 120:1345-54. [PMID: 20237409 PMCID: PMC2846038 DOI: 10.1172/jci38793] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2009] [Accepted: 01/13/2010] [Indexed: 01/07/2023] Open
Abstract
Resistance to thyroid hormone (RTH), a dominantly inherited disorder usually associated with mutations in thyroid hormone receptor beta (THRB), is characterized by elevated levels of circulating thyroid hormones (including thyroxine), failure of feedback suppression of thyrotropin, and variable tissue refractoriness to thyroid hormone action. Raised energy expenditure and hyperphagia are recognized features of hyperthyroidism, but the effects of comparable hyperthyroxinemia in RTH patients are unknown. Here, we show that resting energy expenditure (REE) was substantially increased in adults and children with THRB mutations. Energy intake in RTH subjects was increased by 40%, with marked hyperphagia particularly evident in children. Rates of muscle TCA cycle flux were increased by 75% in adults with RTH, whereas rates of ATP synthesis were unchanged, as determined by 13C/31P magnetic resonance spectroscopy. Mitochondrial coupling index between ATP synthesis and mitochondrial rates of oxidation (as estimated by the ratio of ATP synthesis to TCA cycle flux) was significantly decreased in RTH patients. These data demonstrate that basal mitochondrial substrate oxidation is increased and energy production in the form of ATP synthesis is decreased in the muscle of RTH patients and that resting oxidative phosphorylation is uncoupled in this disorder. Furthermore, these observations suggest that mitochondrial uncoupling in skeletal muscle is a major contributor to increased REE in patients with RTH, due to tissue selective retention of thyroid hormone receptor alpha sensitivity to elevated thyroid hormone levels.
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Affiliation(s)
- Catherine S. Mitchell
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, United Kingdom.
Howard Hughes Medical Institute and
Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut.
Department of Clinical Biochemistry, Addenbrooke’s Hospital.
Department of Medicine, University of Cardiff, United Kingdom.
Department of Diagnostic Radiology and
Department of Cellular and Molecular Physiology, Yale University School of Medicine
| | - David B. Savage
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, United Kingdom.
Howard Hughes Medical Institute and
Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut.
Department of Clinical Biochemistry, Addenbrooke’s Hospital.
Department of Medicine, University of Cardiff, United Kingdom.
Department of Diagnostic Radiology and
Department of Cellular and Molecular Physiology, Yale University School of Medicine
| | - Sylvie Dufour
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, United Kingdom.
Howard Hughes Medical Institute and
Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut.
Department of Clinical Biochemistry, Addenbrooke’s Hospital.
Department of Medicine, University of Cardiff, United Kingdom.
Department of Diagnostic Radiology and
Department of Cellular and Molecular Physiology, Yale University School of Medicine
| | - Nadia Schoenmakers
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, United Kingdom.
Howard Hughes Medical Institute and
Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut.
Department of Clinical Biochemistry, Addenbrooke’s Hospital.
Department of Medicine, University of Cardiff, United Kingdom.
Department of Diagnostic Radiology and
Department of Cellular and Molecular Physiology, Yale University School of Medicine
| | - Peter Murgatroyd
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, United Kingdom.
Howard Hughes Medical Institute and
Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut.
Department of Clinical Biochemistry, Addenbrooke’s Hospital.
Department of Medicine, University of Cardiff, United Kingdom.
Department of Diagnostic Radiology and
Department of Cellular and Molecular Physiology, Yale University School of Medicine
| | - Douglas Befroy
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, United Kingdom.
Howard Hughes Medical Institute and
Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut.
Department of Clinical Biochemistry, Addenbrooke’s Hospital.
Department of Medicine, University of Cardiff, United Kingdom.
Department of Diagnostic Radiology and
Department of Cellular and Molecular Physiology, Yale University School of Medicine
| | - David Halsall
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, United Kingdom.
Howard Hughes Medical Institute and
Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut.
Department of Clinical Biochemistry, Addenbrooke’s Hospital.
Department of Medicine, University of Cardiff, United Kingdom.
Department of Diagnostic Radiology and
Department of Cellular and Molecular Physiology, Yale University School of Medicine
| | - Samantha Northcott
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, United Kingdom.
Howard Hughes Medical Institute and
Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut.
Department of Clinical Biochemistry, Addenbrooke’s Hospital.
Department of Medicine, University of Cardiff, United Kingdom.
Department of Diagnostic Radiology and
Department of Cellular and Molecular Physiology, Yale University School of Medicine
| | - Philippa Raymond-Barker
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, United Kingdom.
Howard Hughes Medical Institute and
Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut.
Department of Clinical Biochemistry, Addenbrooke’s Hospital.
Department of Medicine, University of Cardiff, United Kingdom.
Department of Diagnostic Radiology and
Department of Cellular and Molecular Physiology, Yale University School of Medicine
| | - Suzanne Curran
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, United Kingdom.
Howard Hughes Medical Institute and
Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut.
Department of Clinical Biochemistry, Addenbrooke’s Hospital.
Department of Medicine, University of Cardiff, United Kingdom.
Department of Diagnostic Radiology and
Department of Cellular and Molecular Physiology, Yale University School of Medicine
| | - Elana Henning
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, United Kingdom.
Howard Hughes Medical Institute and
Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut.
Department of Clinical Biochemistry, Addenbrooke’s Hospital.
Department of Medicine, University of Cardiff, United Kingdom.
Department of Diagnostic Radiology and
Department of Cellular and Molecular Physiology, Yale University School of Medicine
| | - Julia Keogh
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, United Kingdom.
Howard Hughes Medical Institute and
Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut.
Department of Clinical Biochemistry, Addenbrooke’s Hospital.
Department of Medicine, University of Cardiff, United Kingdom.
Department of Diagnostic Radiology and
Department of Cellular and Molecular Physiology, Yale University School of Medicine
| | - Penny Owen
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, United Kingdom.
Howard Hughes Medical Institute and
Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut.
Department of Clinical Biochemistry, Addenbrooke’s Hospital.
Department of Medicine, University of Cardiff, United Kingdom.
Department of Diagnostic Radiology and
Department of Cellular and Molecular Physiology, Yale University School of Medicine
| | - John Lazarus
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, United Kingdom.
Howard Hughes Medical Institute and
Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut.
Department of Clinical Biochemistry, Addenbrooke’s Hospital.
Department of Medicine, University of Cardiff, United Kingdom.
Department of Diagnostic Radiology and
Department of Cellular and Molecular Physiology, Yale University School of Medicine
| | - Douglas L. Rothman
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, United Kingdom.
Howard Hughes Medical Institute and
Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut.
Department of Clinical Biochemistry, Addenbrooke’s Hospital.
Department of Medicine, University of Cardiff, United Kingdom.
Department of Diagnostic Radiology and
Department of Cellular and Molecular Physiology, Yale University School of Medicine
| | - I. Sadaf Farooqi
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, United Kingdom.
Howard Hughes Medical Institute and
Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut.
Department of Clinical Biochemistry, Addenbrooke’s Hospital.
Department of Medicine, University of Cardiff, United Kingdom.
Department of Diagnostic Radiology and
Department of Cellular and Molecular Physiology, Yale University School of Medicine
| | - Gerald I. Shulman
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, United Kingdom.
Howard Hughes Medical Institute and
Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut.
Department of Clinical Biochemistry, Addenbrooke’s Hospital.
Department of Medicine, University of Cardiff, United Kingdom.
Department of Diagnostic Radiology and
Department of Cellular and Molecular Physiology, Yale University School of Medicine
| | - Krishna Chatterjee
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, United Kingdom.
Howard Hughes Medical Institute and
Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut.
Department of Clinical Biochemistry, Addenbrooke’s Hospital.
Department of Medicine, University of Cardiff, United Kingdom.
Department of Diagnostic Radiology and
Department of Cellular and Molecular Physiology, Yale University School of Medicine
| | - Kitt Falk Petersen
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, United Kingdom.
Howard Hughes Medical Institute and
Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut.
Department of Clinical Biochemistry, Addenbrooke’s Hospital.
Department of Medicine, University of Cardiff, United Kingdom.
Department of Diagnostic Radiology and
Department of Cellular and Molecular Physiology, Yale University School of Medicine
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Chow L, From A, Seaquist E. Skeletal muscle insulin resistance: the interplay of local lipid excess and mitochondrial dysfunction. Metabolism 2010; 59:70-85. [PMID: 19766267 PMCID: PMC2789850 DOI: 10.1016/j.metabol.2009.07.009] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2009] [Revised: 06/02/2009] [Accepted: 07/09/2009] [Indexed: 01/07/2023]
Affiliation(s)
- Lisa Chow
- University of Minnesota Medical School, Minneapolis, MN 55455, United States.
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Abstract
Energy homeostasis is critical for the survival of species. Therefore, multiple and complex mechanisms have evolved to regulate energy intake and expenditure to maintain body weight. For weight maintenance, not only does energy intake have to match energy expenditure, but also macronutrient intake must balance macronutrient oxidation. However, this equilibrium seems to be particularly difficult to achieve in individuals with low fat oxidation, low energy expenditure, low sympathetic activity or low levels of spontaneous physical activity, as in addition to excess energy intake, all of these factors explain the tendency of some people to gain weight. Additionally, large variability in weight change is observed when energy surplus is imposed experimentally or spontaneously. Clearly, the data suggest a strong genetic influence on body weight regulation implying a normal physiology in an 'obesogenic' environment. In this study, we also review evidence that carbohydrate balance may represent the potential signal that regulates energy homeostasis by impacting energy intake and body weight. Because of the small storage capacity for carbohydrate and its importance for metabolism in many tissues and organs, carbohydrate balance must be maintained at a given level. This drive for balance may in turn cause increased energy intake when consuming a diet high in fat and low in carbohydrate. If sustained over time, such an increase in energy intake cannot be detected by available methods, but may cause meaningful increases in body weight. The concept of metabolic flexibility and its impact on body weight regulation is also presented.
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Affiliation(s)
- J Galgani
- Human Physiology Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA
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35
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Xu S, Shen J. Studying Enzymes by In Vivo C Magnetic Resonance Spectroscopy. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2009; 55:266-283. [PMID: 20161496 PMCID: PMC2796782 DOI: 10.1016/j.pnmrs.2009.06.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Affiliation(s)
- Su Xu
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
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36
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Thyroid hormone mimetics: potential applications in atherosclerosis, obesity and type 2 diabetes. Nat Rev Drug Discov 2009; 8:308-20. [PMID: 19337272 DOI: 10.1038/nrd2830] [Citation(s) in RCA: 174] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Thyroid hormones influence heart rate, serum lipids, metabolic rate, body weight and multiple aspects of lipid, carbohydrate, protein and mineral metabolism. Although increased thyroid hormone levels can improve serum lipid profiles and reduce fat, these positive effects are counterbalanced by harmful effects on the heart, muscle and bone. Thus, attempts to use thyroid hormones for cholesterol-lowering and weight loss purposes have so far been limited. However, over the past decade, thyroid hormone analogues that are capable of uncoupling beneficial effects from deleterious effects have been developed. Such drugs could serve as powerful new tools to address two of the largest medical problems in developed countries--atherosclerosis and obesity.
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37
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Grozovsky R, Ribich S, Rosene ML, Mulcahey MA, Huang SA, Patti ME, Bianco AC, Kim BW. Type 2 deiodinase expression is induced by peroxisomal proliferator-activated receptor-gamma agonists in skeletal myocytes. Endocrinology 2009; 150:1976-83. [PMID: 19036883 PMCID: PMC2659265 DOI: 10.1210/en.2008-0938] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The thyroid hormone activating type 2 deiodinase (D2) is known to play a role in brown adipose tissue-mediated adaptive thermogenesis in rodents, but the finding of D2 in skeletal muscle raises the possibility of a broader metabolic role. In the current study, we examined the regulation of the D2 pathway in primary skeletal muscle myoblasts taken from both humans and mice. We found that pioglitazone treatment led to a 1.6- to 1.9-fold increase in primary human skeletal myocyte D2 activity; this effect was seen with other peroxisomal proliferator-activated receptor-gamma agonists. D2 activity in primary murine skeletal myotubes increased 2.8-fold in response to 5 microM pioglitazone and 1.6-fold in response to 5 nM insulin and increased in a dose-dependent manner in response to lithocholic acid (maximum response at 25 microM was approximately 3.8-fold). We compared Akt phosphorylation in primary myotubes derived from wild-type and D2 knockout (D2KO) mice: phospho-Akt was reduced by 50% in the D2KO muscle after 1 nM insulin exposure. Expression of T(3)-responsive muscle genes via quantitative RT-PCR suggests that D2KO cells have decreased thyroid hormone signaling, which could contribute to the abnormalities in insulin signaling. D2 activity in skeletal muscle fragments from both murine and human sources was low, on the order of about 0.01 fmol/min . mg of muscle protein. The phenotypic changes seen with D2KO cells support a metabolic role for D2 in muscle, hinting at a D2-mediated linkage between thyroid hormone and insulin signaling, but the low activity calls into question whether skeletal muscle D2 is a major source of plasma T(3).
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Affiliation(s)
- Renata Grozovsky
- Division of Endocrinology, Brighamand Women's Hospital, Children's Hospital Boston, Boston, Massachusetts 02115, USA
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38
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Multimodal neuroimaging provides a highly consistent picture of energy metabolism, validating 31P MRS for measuring brain ATP synthesis. Proc Natl Acad Sci U S A 2009; 106:3988-93. [PMID: 19234118 DOI: 10.1073/pnas.0806516106] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Neuroimaging methods have considerably developed over the last decades and offer various noninvasive approaches for measuring cerebral metabolic fluxes connected to energy metabolism, including PET and magnetic resonance spectroscopy (MRS). Among these methods, (31)P MRS has the particularity and advantage to directly measure cerebral ATP synthesis without injection of labeled precursor. However, this approach is methodologically challenging, and further validation studies are required to establish (31)P MRS as a robust method to measure brain energy synthesis. In the present study, we performed a multimodal imaging study based on the combination of 3 neuroimaging techniques, which allowed us to obtain an integrated picture of brain energy metabolism and, at the same time, to validate the saturation transfer (31)P MRS method as a quantitative measurement of brain ATP synthesis. A total of 29 imaging sessions were conducted to measure glucose consumption (CMRglc), TCA cycle flux (V(TCA)), and the rate of ATP synthesis (V(ATP)) in primate monkeys by using (18)F-FDG PET scan, indirect (13)C MRS, and saturation transfer (31)P MRS, respectively. These 3 complementary measurements were performed within the exact same area of the brain under identical physiological conditions, leading to: CMRglc = 0.27 +/- 0.07 micromol x g(-1) x min(-1), V(TCA) = 0.63 +/- 0.12 micromol x g(-1) x min(-1), and V(ATP) = 7.8 +/- 2.3 micromol x g(-1) x min(-1). The consistency of these 3 fluxes with literature and, more interestingly, one with each other, demonstrates the robustness of saturation transfer (31)P MRS for directly evaluating ATP synthesis in the living brain.
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Abstract
Mitochondria play a pivotal role in cellular function, not only as a major site of ATP production, but also by regulating energy expenditure, apoptosis signaling, and production of reactive oxygen species. Altered mitochondrial function is reported to be a key underlying mechanism of many pathological states and in the aging process. Functional measurements of intact mitochondria isolated from fresh tissue provides distinct information regarding the function of these organelles that complements conventional mitochondrial assays using previously frozen tissue as well as in vivo assessment using techniques such as magnetic resonance and near-infrared spectroscopy. This chapter describes the process by which mitochondria are isolated from small amounts of human skeletal muscle obtained by needle biopsy and two approaches used to assess mitochondrial oxidative capacity and other key components of mitochondrial physiology. We first describe a bioluminescent approach for measuring the rates of mitochondrial ATP production. Firefly luciferase catalyzes a light-emitting reaction whereby the substrate luciferin is oxidized in an ATP-dependent manner. A luminometer is used to quantify the light signal, which is proportional to ATP concentration. We also review a method involving polarographic measurement of oxygen consumption. Measurements of oxygen consumption, which previously required large amounts of tissue, are now feasible with very small amounts of sample obtained by needle biopsy due to recent advances in the field of high-resolution respirometry. We illustrate how careful attention to substrate combinations and inhibitors allows an abundance of unique functional information to be obtained from isolated mitochondria, including function at various energetic states, oxidative capacity with electron flow through distinct complexes, coupling of oxygen consumption to ATP production, and membrane integrity. These measurements, together with studies of mitochondrial DNA abundance, mRNA levels, protein expression, and synthesis rates of mitochondrial proteins provide insightful mechanistic information about mitochondria in a variety of tissue types.
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Affiliation(s)
- Ian R Lanza
- Division of Endocrinology, Endocrinology Research Unit, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
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40
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Befroy DE, Falk Petersen K, Rothman DL, Shulman GI. Assessment of in vivo mitochondrial metabolism by magnetic resonance spectroscopy. Methods Enzymol 2009; 457:373-93. [PMID: 19426879 DOI: 10.1016/s0076-6879(09)05021-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Magnetic resonance spectroscopy (MRS), a companion technique to the more familiar MRI scan, has emerged as a powerful technique for studying metabolism noninvasively in a variety of tissues. In this article, we review two techniques that we have developed which take advantage of the unique characteristics of (31)P and (13)C MRS to investigate two distinct parameters of muscle mitochondrial metabolism; ATP production can be estimated by using the (31)P saturation-transfer technique, and oxidation via the TCA cycle can be modeled from (13)C MRS data obtained during the metabolism of a (13)C-labeled substrate. We will also examine applications of the techniques to investigate how these parameters of muscle mitochondrial metabolism are modulated in insulin resistant and endurance trained individuals.
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Affiliation(s)
- Douglas E Befroy
- Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut, USA
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41
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Paradoxical effects of increased expression of PGC-1alpha on muscle mitochondrial function and insulin-stimulated muscle glucose metabolism. Proc Natl Acad Sci U S A 2008; 105:19926-31. [PMID: 19066218 DOI: 10.1073/pnas.0810339105] [Citation(s) in RCA: 225] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Peroxisome proliferator-activated receptor-gamma coactivator (PGC)-1alpha has been shown to play critical roles in regulating mitochondria biogenesis, respiration, and muscle oxidative phenotype. Furthermore, reductions in the expression of PGC-1alpha in muscle have been implicated in the pathogenesis of type 2 diabetes. To determine the effect of increased muscle-specific PGC-1alpha expression on muscle mitochondrial function and glucose and lipid metabolism in vivo, we examined body composition, energy balance, and liver and muscle insulin sensitivity by hyperinsulinemic-euglycemic clamp studies and muscle energetics by using (31)P magnetic resonance spectroscopy in transgenic mice. Increased expression of PGC-1alpha in muscle resulted in a 2.4-fold increase in mitochondrial density, which was associated with an approximately 60% increase in the unidirectional rate of ATP synthesis. Surprisingly, there was no effect of increased muscle PGC-1alpha expression on whole-body energy expenditure, and PGC-1alpha transgenic mice were more prone to fat-induced insulin resistance because of decreased insulin-stimulated muscle glucose uptake. The reduced insulin-stimulated muscle glucose uptake could most likely be attributed to a relative increase in fatty acid delivery/triglyceride reesterfication, as reflected by increased expression of CD36, acyl-CoA:diacylglycerol acyltransferase1, and mitochondrial acyl-CoA:glycerol-sn-3-phosphate acyltransferase, that may have exceeded mitochondrial fatty acid oxidation, resulting in increased intracellular lipid accumulation and an increase in the membrane to cytosol diacylglycerol content. This, in turn, caused activation of PKC, decreased insulin signaling at the level of insulin receptor substrate-1 (IRS-1) tyrosine phosphorylation, and skeletal muscle insulin resistance.
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42
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Gereben B, Zavacki AM, Ribich S, Kim BW, Huang SA, Simonides WS, Zeöld A, Bianco AC. Cellular and molecular basis of deiodinase-regulated thyroid hormone signaling. Endocr Rev 2008; 29:898-938. [PMID: 18815314 PMCID: PMC2647704 DOI: 10.1210/er.2008-0019] [Citation(s) in RCA: 552] [Impact Index Per Article: 34.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2008] [Accepted: 08/15/2008] [Indexed: 02/06/2023]
Abstract
The iodothyronine deiodinases initiate or terminate thyroid hormone action and therefore are critical for the biological effects mediated by thyroid hormone. Over the years, research has focused on their role in preserving serum levels of the biologically active molecule T(3) during iodine deficiency. More recently, a fascinating new role of these enzymes has been unveiled. The activating deiodinase (D2) and the inactivating deiodinase (D3) can locally increase or decrease thyroid hormone signaling in a tissue- and temporal-specific fashion, independent of changes in thyroid hormone serum concentrations. This mechanism is particularly relevant because deiodinase expression can be modulated by a wide variety of endogenous signaling molecules such as sonic hedgehog, nuclear factor-kappaB, growth factors, bile acids, hypoxia-inducible factor-1alpha, as well as a growing number of xenobiotic substances. In light of these findings, it seems clear that deiodinases play a much broader role than once thought, with great ramifications for the control of thyroid hormone signaling during vertebrate development and metamorphosis, as well as injury response, tissue repair, hypothalamic function, and energy homeostasis in adults.
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Affiliation(s)
- Balázs Gereben
- Laboratory of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
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43
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Trenell MI, Hollingsworth KG, Lim EL, Taylor R. Increased daily walking improves lipid oxidation without changes in mitochondrial function in type 2 diabetes. Diabetes Care 2008; 31:1644-9. [PMID: 18487474 PMCID: PMC2494664 DOI: 10.2337/dc08-0303] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE To determine whether increased daily physical activity improves mitochondrial function and/or lipid oxidation in type 2 diabetes. RESEARCH DESIGN AND METHODS Volunteers with (n = 10) and without (n = 10) type 2 diabetes were matched for habitual physical activity, age, sex, and weight. Basal and maximal mitochondrial activity, physical activity, and resting substrate oxidation were measured at baseline and after 2 and 8 weeks of increased physical activity. RESULTS Baseline physical activity (6,450 +/- 851 vs. 7,638 +/- 741 steps/day), basal ATP use (12 +/- 1 vs. 12 +/- 1 micromol x ml(-1) x min(-1)), phosphocreatine recovery from exercise (31 +/- 5 vs. 29 +/- 3 s), and basal lipid oxidation (0.57 +/- 0.07 vs. 0.65 +/- 0.06 mg x kg body wt(-1) x min(-1)) were similar in people with and without type 2 diabetes. There was a significant increase in physical activity after 8 weeks (12,322 +/- 1,979 vs. 9,187 +/- 1,159 steps/day, respectively). Following increased physical activity, there were no changes in basal ATP use or phosphocreatine recovery after exercise in either group. Basal lipid oxidation increased after 8 weeks of increased physical activity in people with type 2 diabetes (0.79 +/- 0.08 mg x kg(-1) x min(-1)) but not people without (0.68 +/- 0.13 mg x kg body wt(-1) x min(-1)). CONCLUSIONS Resting and maximal ATP turnover are not impaired in people with well-controlled type 2 diabetes compared with control subjects matched for physical activity as well as age and weight. Increased unsupervised daily physical activity is sustainable and improves lipid oxidation independent of change in mitochondrial activity in people with type 2 diabetes.
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Affiliation(s)
- Michael I Trenell
- Diabetes Research Group, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK.
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44
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Wijers SLJ, Schrauwen P, Saris WHM, van Marken Lichtenbelt WD. Human skeletal muscle mitochondrial uncoupling is associated with cold induced adaptive thermogenesis. PLoS One 2008; 3:e1777. [PMID: 18335051 PMCID: PMC2258415 DOI: 10.1371/journal.pone.0001777] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2007] [Accepted: 02/11/2008] [Indexed: 11/24/2022] Open
Abstract
Background Mild cold exposure and overfeeding are known to elevate energy expenditure in mammals, including humans. This process is called adaptive thermogenesis. In small animals, adaptive thermogenesis is mainly caused by mitochondrial uncoupling in brown adipose tissue and regulated via the sympathetic nervous system. In humans, skeletal muscle is a candidate tissue, known to account for a large part of the epinephrine-induced increase in energy expenditure. However, mitochondrial uncoupling in skeletal muscle has not extensively been studied in relation to adaptive thermogenesis in humans. Therefore we hypothesized that cold-induced adaptive thermogenesis in humans is accompanied by an increase in mitochondrial uncoupling in skeletal muscle. Methodology/Principal Findings The metabolic response to mild cold exposure in 11 lean, male subjects was measured in a respiration chamber at baseline and mild cold exposure. Skeletal muscle mitochondrial uncoupling (state 4) was measured in muscle biopsies taken at the end of the respiration chamber stays. Mild cold exposure caused a significant increase in 24h energy expenditure of 2.8% (0.32 MJ/day, range of −0.21 to 1.66 MJ/day, p<0.05). The individual increases in energy expenditure correlated to state 4 respiration (p<0.02, R2 = 0.50). Conclusions/Significance This study for the first time shows that in humans, skeletal muscle has the intrinsic capacity for cold induced adaptive thermogenesis via mitochondrial uncoupling under physiological conditions. This opens possibilities for mitochondrial uncoupling as an alternative therapeutic target in the treatment of obesity.
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Affiliation(s)
- Sander L J Wijers
- Department of Human Biology, Nutrition and Toxicology Research Institute Maastricht (NUTRIM), Maastricht University, The Netherlands.
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45
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Savage DB, Petersen KF, Shulman GI. Disordered lipid metabolism and the pathogenesis of insulin resistance. Physiol Rev 2007; 87:507-20. [PMID: 17429039 PMCID: PMC2995548 DOI: 10.1152/physrev.00024.2006] [Citation(s) in RCA: 727] [Impact Index Per Article: 42.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Although abnormal glucose metabolism defines type 2 diabetes mellitus (T2DM) and accounts for many of its symptoms and complications, efforts to understand the pathogenesis of T2DM are increasingly focused on disordered lipid metabolism. Here we review recent human studies exploring the mechanistic links between disorders of fatty acid/lipid metabolism and insulin resistance. As "mouse models of insulin resistance" were comprehensively reviewed in Physiological Reviews by Nandi et al. in 2004, we will concentrate on human studies involving the use of isotopes and/or magnetic resonance spectroscopy, occasionally drawing on mouse models which provide additional mechanistic insight.
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Affiliation(s)
- David B. Savage
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, 06536-8012
| | - Kitt Falk Petersen
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, 06536-8012
| | - Gerald I. Shulman
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, 06536-8012
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT, 06536-8012
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46
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Szendroedi J, Schmid AI, Chmelik M, Toth C, Brehm A, Krssak M, Nowotny P, Wolzt M, Waldhausl W, Roden M. Muscle mitochondrial ATP synthesis and glucose transport/phosphorylation in type 2 diabetes. PLoS Med 2007; 4:e154. [PMID: 17472434 PMCID: PMC1858707 DOI: 10.1371/journal.pmed.0040154] [Citation(s) in RCA: 194] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2006] [Accepted: 02/28/2007] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Muscular insulin resistance is frequently characterized by blunted increases in glucose-6-phosphate (G-6-P) reflecting impaired glucose transport/phosphorylation. These abnormalities likely relate to excessive intramyocellular lipids and mitochondrial dysfunction. We hypothesized that alterations in insulin action and mitochondrial function should be present even in nonobese patients with well-controlled type 2 diabetes mellitus (T2DM). METHODS AND FINDINGS We measured G-6-P, ATP synthetic flux (i.e., synthesis) and lipid contents of skeletal muscle with (31)P/(1)H magnetic resonance spectroscopy in ten patients with T2DM and in two control groups: ten sex-, age-, and body mass-matched elderly people; and 11 younger healthy individuals. Although insulin sensitivity was lower in patients with T2DM, muscle lipid contents were comparable and hyperinsulinemia increased G-6-P by 50% (95% confidence interval [CI] 39%-99%) in all groups. Patients with diabetes had 27% lower fasting ATP synthetic flux compared to younger controls (p = 0.031). Insulin stimulation increased ATP synthetic flux only in controls (younger: 26%, 95% CI 13%-42%; older: 11%, 95% CI 2%-25%), but failed to increase even during hyperglycemic hyperinsulinemia in patients with T2DM. Fasting free fatty acids and waist-to-hip ratios explained 44% of basal ATP synthetic flux. Insulin sensitivity explained 30% of insulin-stimulated ATP synthetic flux. CONCLUSIONS Patients with well-controlled T2DM feature slightly lower flux through muscle ATP synthesis, which occurs independently of glucose transport /phosphorylation and lipid deposition but is determined by lipid availability and insulin sensitivity. Furthermore, the reduction in insulin-stimulated glucose disposal despite normal glucose transport/phosphorylation suggests further abnormalities mainly in glycogen synthesis in these patients.
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Affiliation(s)
- Julia Szendroedi
- Department of Internal Medicine 3, University of Vienna, Vienna, Austria
- Karl-Landsteiner Institute of Endocrinology and Metabolism, Vienna, Austria
| | - Albrecht I Schmid
- Karl-Landsteiner Institute of Endocrinology and Metabolism, Vienna, Austria
- High-Field Magnetic Resonance Centre of Excellence, Medical University of Vienna, Vienna, Austria
| | - Marek Chmelik
- Karl-Landsteiner Institute of Endocrinology and Metabolism, Vienna, Austria
- High-Field Magnetic Resonance Centre of Excellence, Medical University of Vienna, Vienna, Austria
| | - Christian Toth
- Karl-Landsteiner Institute of Endocrinology and Metabolism, Vienna, Austria
| | - Attila Brehm
- First Medical Department, Hanusch Hospital, Vienna, Austria
| | - Martin Krssak
- High-Field Magnetic Resonance Centre of Excellence, Medical University of Vienna, Vienna, Austria
| | - Peter Nowotny
- Department of Internal Medicine 3, University of Vienna, Vienna, Austria
| | - Michael Wolzt
- Department of Internal Medicine 3, University of Vienna, Vienna, Austria
| | - Werner Waldhausl
- Department of Internal Medicine 3, University of Vienna, Vienna, Austria
| | - Michael Roden
- Karl-Landsteiner Institute of Endocrinology and Metabolism, Vienna, Austria
- First Medical Department, Hanusch Hospital, Vienna, Austria
- * To whom correspondence should be addressed. E-mail:
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47
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Befroy DE, Petersen KF, Dufour S, Mason GF, de Graaf RA, Rothman DL, Shulman GI. Impaired mitochondrial substrate oxidation in muscle of insulin-resistant offspring of type 2 diabetic patients. Diabetes 2007; 56:1376-81. [PMID: 17287462 PMCID: PMC2995532 DOI: 10.2337/db06-0783] [Citation(s) in RCA: 325] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Insulin resistance is the best predictor for the development of diabetes in offspring of type 2 diabetic patients, but the mechanism responsible for it remains unknown. Recent studies have demonstrated increased intramyocellular lipid, decreased mitochondrial ATP synthesis, and decreased mitochondrial density in the muscle of lean, insulin-resistant offspring of type 2 diabetic patients. These data suggest an important role for mitochondrial dysfunction in the pathogenesis of type 2 diabetes. To further explore this hypothesis, we assessed rates of substrate oxidation in the muscle of these same individuals using (13)C magnetic resonance spectroscopy (MRS). Young, lean, insulin-resistant offspring of type 2 diabetic patients and insulin-sensitive control subjects underwent (13)C MRS studies to noninvasively assess rates of substrate oxidation in muscle by monitoring the incorporation of (13)C label into C(4) glutamate during a [2-(13)C]acetate infusion. Using this approach, we found that rates of muscle mitochondrial substrate oxidation were decreased by 30% in lean, insulin-resistant offspring (59.8 +/- 5.1 nmol x g(-1) x min(-1), P = 0.02) compared with insulin-sensitive control subjects (96.1 +/- 16.3 nmol x g(-1) x min(-1)). These data support the hypothesis that insulin resistance in skeletal muscle of insulin-resistant offspring is associated with dysregulation of intramyocellular fatty acid metabolism, possibly because of an inherited defect in the activity of mitochondrial oxidative phosphorylation.
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Affiliation(s)
- Douglas E. Befroy
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Kitt Falk Petersen
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Sylvie Dufour
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut
| | - Graeme F. Mason
- Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut
| | - Robin A. de Graaf
- Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut
| | - Douglas L. Rothman
- Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut
| | - Gerald I. Shulman
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut
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48
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Pomplun D, Voigt A, Schulz TJ, Thierbach R, Pfeiffer AF, Ristow M. Reduced expression of mitochondrial frataxin in mice exacerbates diet-induced obesity. Proc Natl Acad Sci U S A 2007; 104:6377-81. [PMID: 17404227 PMCID: PMC1847459 DOI: 10.1073/pnas.0611631104] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2006] [Indexed: 01/05/2023] Open
Abstract
Published evidence suggests that adiposity in humans may be linked to impaired energy expenditure for reasons widely unresolved. We have generated mice with a systemic impairment of oxidative phosphorylation (OXPHOS) due to aP2 cre-mediated targeted disruption, and unexpectedly ubiquitous reduction of mitochondrial frataxin protein expression. Only when maintained on a high-calorie diet resembling Westernized eating habits, these animals accumulate additional body fat, leading to increased body mass, and develop diabetes mellitus, despite the fact that both calorie uptake and physical activity were identical to that in control animals. This phenotype is caused by a mild but significant reduction in total energy expenditure paralleled by increased expression of ATP citrate lyase, a rate-limiting step in de novo synthesis of fatty acids and triglycerides. Taken together, these findings indicate that a limited impairment in oxidative metabolism within the mitochondria directly predisposes mammals to excessive body weight gain.
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Affiliation(s)
- Doreen Pomplun
- *Department of Clinical Nutrition, German Institute of Human Nutrition, D-14558 Potsdam-Rehbrücke, Germany
- Department of Human Nutrition, Institute of Nutrition, University of Jena, D-07743 Jena, Germany; and
| | - Anja Voigt
- Institute of Nutrition, Department of Nutritional Toxicology, University of Potsdam, D-14558 Potsdam, Germany
| | - Tim J. Schulz
- *Department of Clinical Nutrition, German Institute of Human Nutrition, D-14558 Potsdam-Rehbrücke, Germany
- Department of Human Nutrition, Institute of Nutrition, University of Jena, D-07743 Jena, Germany; and
| | - René Thierbach
- Institute of Nutrition, Department of Nutritional Toxicology, University of Potsdam, D-14558 Potsdam, Germany
| | - Andreas F. Pfeiffer
- *Department of Clinical Nutrition, German Institute of Human Nutrition, D-14558 Potsdam-Rehbrücke, Germany
| | - Michael Ristow
- *Department of Clinical Nutrition, German Institute of Human Nutrition, D-14558 Potsdam-Rehbrücke, Germany
- Department of Human Nutrition, Institute of Nutrition, University of Jena, D-07743 Jena, Germany; and
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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] [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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50
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Bianco AC, Kim BW. Deiodinases: implications of the local control of thyroid hormone action. J Clin Invest 2007; 116:2571-9. [PMID: 17016550 PMCID: PMC1578599 DOI: 10.1172/jci29812] [Citation(s) in RCA: 537] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The deiodinases activate or inactivate thyroid hormone, and their importance in thyroid hormone homeostasis has become increasingly clear with the availability of deiodinase-deficient animals. At the same time, heightened interest in the field has been generated following the discovery that the type 2 deiodinase can be an important component in both the Hedgehog signaling pathway and the G protein-coupled bile acid receptor 1-mediated (GPBAR1-mediated) signaling cascade. The discovery of these new roles for the deiodinases indicates that tissue-specific deiodination plays a much broader role than once thought, extending into the realms of developmental biology and metabolism.
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Affiliation(s)
- Antonio C Bianco
- Thyroid Section, Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA.
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