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Giacona JM, Afridi A, Bezan Petric U, Johnson T, Pastor J, Ren J, Sandon L, Malloy C, Pandey A, Shah A, Berry JD, Moe OW, Vongpatanasin W. Association between dietary phosphate intake and skeletal muscle energetics in adults without cardiovascular disease. J Appl Physiol (1985) 2024; 136:1007-1014. [PMID: 38482570 DOI: 10.1152/japplphysiol.00818.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 02/05/2024] [Accepted: 02/24/2024] [Indexed: 04/17/2024] Open
Abstract
Highly bioavailable inorganic phosphate (Pi) is present in large quantities in the typical Western diet and represents a large fraction of total phosphate intake. Dietary Pi excess induces exercise intolerance and skeletal muscle mitochondrial dysfunction in normal mice. However, the relevance of this to humans remains unknown. The study was conducted on 13 individuals without a history of cardiopulmonary disease (46% female, 15% Black participants) enrolled in the pilot-phase of the Dallas Heart and Mind Study. Total dietary phosphate was estimated from 24-h dietary recall (ASA24). Muscle ATP synthesis was measured at rest, and phosphocreatinine (PCr) dynamics was measured during plantar flexion exercise using 7-T 31P magnetic resonance (MR) spectroscopy in the calf muscle. Correlation was assessed between dietary phosphate intake normalized to total caloric intake, resting ATP synthesis, and PCr depletion during exercise. Higher dietary phosphate intake was associated with lower resting ATP synthesis (r = -0.62, P = 0.03), and with higher levels of PCr depletion during plantar flexion exercise relative to the resting period (r = -0.72; P = 0.004). These associations remain significant after adjustment for age and estimated glomerular filtration rate (both P < 0.05). High dietary phosphate intake was also associated with lower serum Klotho levels, and Klotho levels are in turn associated with PCr depletion and higher ADP accumulation post exercise. Our study suggests that higher dietary phosphate is associated with reduced skeletal muscle mitochondrial function at rest and exercise in humans providing new insight into potential mechanisms linking the Western diet to impaired energy metabolism.NEW & NOTEWORTHY This is the first translational research study directly demonstrating the adverse effects of dietary phosphate on muscle energy metabolism in humans. Importantly, our data show that dietary phosphate is associated with impaired muscle ATP synthesis at rest and during exercise, independent of age and renal function. This is a new biologic paradigm with significant clinical dietary implications.
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Affiliation(s)
- John M Giacona
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Areeb Afridi
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Ursa Bezan Petric
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Talon Johnson
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Johanne Pastor
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Jimin Ren
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, United States
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Lona Sandon
- Department of Clinical Nutrition, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Craig Malloy
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, United States
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Ambarish Pandey
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Amil Shah
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Jarett D Berry
- Department of Internal Medicine, University of Texas Health Science Center at Tyler, Tyler, Texas, United States
| | - Orson W Moe
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, United States
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Wanpen Vongpatanasin
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, United States
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Silva de Moura S, de Assis Dias Martins-Júnior F, Cruz de Oliveira E, Coelho DB, Boari D, Lima-Silva AE, Motta-Santos D, Augusto Souza Dos Santos R, Becker LK. Effects of oral HPΒCD-angiotensin-(1-7) supplementation on recreational mountain bike athletes: a crossover study. PHYSICIAN SPORTSMED 2024; 52:65-76. [PMID: 36752064 DOI: 10.1080/00913847.2023.2175587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Accepted: 01/29/2023] [Indexed: 02/09/2023]
Abstract
BACKGROUND Supplementation with Angiotensin-(1-7) [(Ang-1-7)] has received considerable attention due to its possible ergogenic effects on physical performance. The effects of a single dose of Ang-(1-7) on the performance of mountain bike (MTB) athletes during progressive load tests performed until the onset of voluntary fatigue have previously been demonstrated. This study tested the effects of Ang-(1-7) in two different exercise protocols with different metabolic demands: aerobic (time trial) and anaerobic (repeated sprint). METHODS Twenty one male recreational athletes were given capsules containing an oral formulation of HPβCD-Ang-(1-7) (0.8 mg) and HPβCD-placebo (only HPβCD) over a 7-day interval; a double-blind randomized crossover design was used. Physical performance was examined using two protocols: a 20-km cycling time trial or 4 × 30-s repeated all-out sprints on a leg cycle ergometer. Data were collected before and after physical tests to assess fatigue parameters, and included lactate levels, and muscle activation during the sprint protocol as evaluated by electromyography (EMG); cardiovascular parameters: diastolic and systolic blood pressure and heart rate; and performance parameters, time to complete (time trial), maximum power and mean power (repeated sprint). RESULTS Supplementation with an oral formulation of HPβCD-Ang-(1-7) reduced basal plasma lactate levels and promoted the maintenance of plasma glucose levels after repeated sprints. Supplementation with HPβCD-Ang-(1-7) also increased baseline plasma nitrite levels and reduced resting diastolic blood pressure in a time trial protocol. HPβCD-Ang-(1-7) had no effect on the time trial or repeat sprint performance, or on the EMG recordings of the vastus lateralis and vastus medialis. CONCLUSIONS Supplementation with HPβCD-Ang-(1-7) did not improve physical performance in time trial or in repeated sprints; however, it promoted the maintenance of plasma glucose and lactate levels after the sprint protocol and at rest, respectively. In addition, HPβCD-Ang-(1-7) also increased resting plasma nitrite levels and reduced diastolic blood pressure in the time trial protocol. TRIAL REGISTRATION RBR-2nbmpbc, registered January 6th, 2023. The study was prospectively registered.
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Affiliation(s)
| | | | | | | | - Daniel Boari
- Biomedical Engineering, Federal University of ABC, São Paulo, Brazil
| | | | - Daisy Motta-Santos
- Department of Sports, School of Physical Education, Physiotherapy and Occupational Therapy, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Robson Augusto Souza Dos Santos
- Department of Physiology and Biophysics, Federal University of Minas Gerais, and National Institute Science and Technology-NANOBIOPHAR-CNPQ/MCT, Belo Horizonte, Brazil
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Ohta H, Vo NMV, Hata J, Terawaki K, Shirakawa T, Okano HJ. Utilizing Dynamic Phosphorous-31 Magnetic Resonance Spectroscopy for the Early Detection of Acute Compartment Syndrome: A Pilot Study on Rats. Diagnostics (Basel) 2021; 11:586. [PMID: 33805144 PMCID: PMC8064087 DOI: 10.3390/diagnostics11040586] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 03/20/2021] [Accepted: 03/21/2021] [Indexed: 01/15/2023] Open
Abstract
INTRODUCTION Disasters, including terrorism and earthquakes, are significant threats to people and may lead to many people requiring rescue. The longer the rescue takes, the higher the chances of an individual contracting acute compartment syndrome (ACS). ACS is fatal if diagnosed too late, and early diagnosis and treatment are essential. OBJECTIVE To assess the ability of dynamic phosphorus magnetic resonance spectroscopy (31P-MRS) in the early detection of muscular damage in ACS. MATERIALS AND METHODS Six ACS model rats were used for serial 31P-MRS scanning (9.4 Tesla). Skeletal muscle metabolism, represented by the levels of phosphocreatine (PCr), inorganic phosphate (Pi), and adenosine triphosphate (ATP), was assessed. The PCr/(Pi + PCr) ratio, which decreases with ischemia, was compared with simultaneously sampled plasma creatine phosphokinase (CPK), a muscle damage marker. RESULTS The PCr/(Pi + PCr) ratio significantly decreased after inducing ischemia (from 0.86 ± 0.10 to 0.18 ± 0.06; p < 0.05), while CPK did not change significantly (from 89 ± 29.46 to 241.50 ± 113.28; p > 0.05). The intracellular and arterial pH index decreased over time, revealing significant differences at 120 min post-ischemia (from 7.09 ± 0.01 to 6.43 ± 0.13, and from 7.47 ± 0.03 to 7.39 ± 0.04, respectively). In the reperfusion state, the spectra and pH did not return to the original values. CONCLUSIONS The dynamic 31P-MRS technique can rapidly detect changes in muscle bioenergetics. This technique is a promising non-invasive method for determining early muscular damage in ACS.
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Affiliation(s)
- Hiroki Ohta
- Division of Regenerative Medicine, Research Center for Medical Sciences, The Jikei University School of Medicine, Tokyo 105-8461, Japan; (H.O.); (N.-M.V.V.); (J.H.); (K.T.)
| | - Nhat-Minh Van Vo
- Division of Regenerative Medicine, Research Center for Medical Sciences, The Jikei University School of Medicine, Tokyo 105-8461, Japan; (H.O.); (N.-M.V.V.); (J.H.); (K.T.)
- Department of Radiological Sciences, Tokyo Metropolitan University, Tokyo 116-0012, Japan;
| | - Junichi Hata
- Division of Regenerative Medicine, Research Center for Medical Sciences, The Jikei University School of Medicine, Tokyo 105-8461, Japan; (H.O.); (N.-M.V.V.); (J.H.); (K.T.)
| | - Koshiro Terawaki
- Division of Regenerative Medicine, Research Center for Medical Sciences, The Jikei University School of Medicine, Tokyo 105-8461, Japan; (H.O.); (N.-M.V.V.); (J.H.); (K.T.)
- Department of Radiological Sciences, Tokyo Metropolitan University, Tokyo 116-0012, Japan;
| | - Takako Shirakawa
- Department of Radiological Sciences, Tokyo Metropolitan University, Tokyo 116-0012, Japan;
| | - Hirotaka James Okano
- Division of Regenerative Medicine, Research Center for Medical Sciences, The Jikei University School of Medicine, Tokyo 105-8461, Japan; (H.O.); (N.-M.V.V.); (J.H.); (K.T.)
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Sedivy P, Dezortova M, Drobny M, Dubsky M, Dusilova T, Kovar J, Hajek M. Origin of the 31 P MR signal at 5.3 ppm in patients with critical limb ischemia. NMR IN BIOMEDICINE 2020; 33:e4295. [PMID: 32180296 DOI: 10.1002/nbm.4295] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 02/28/2020] [Accepted: 02/29/2020] [Indexed: 06/10/2023]
Abstract
An unknown intense signal (Pun ) with a mean chemical shift of 5.3 ppm was observed in 31 P MR spectra from the calf muscles of patients with the diabetic foot syndrome. The aim of the study was to identify the origin of this signal and its potential as a biomarker of muscle injury. Calf muscles of 68 diabetic patients (66.3 ± 8.6 years; body mass index = 28.2 ± 4.3 kg/m2 ) and 12 age-matched healthy controls were examined by (dynamic) 31 P MRS (3 T system, 31 P/1 H coil). Phantoms (glucose-1-phosphate, Pi and PCr) were measured at pH values of 7.05 and 7.51. At rest, Pun signals with intensities higher than 50% of the Pi intensity were observed in 10 of the 68 examined diabetic subjects. We tested two hypothetical origins of the Pun signal: (1) phosphorus from phosphoesters and (2) phosphorus from extra- and intracellular alkaline phosphate pools. 2,3-diphosphoglycerate and glucose-1-phosphate are the only phosphoesters with signals in the chemical shift region close to 5.3 ppm. Both compounds can be excluded: 2,3-diphosphoglycerate due to the missing second signal component at 6.31 ppm; glucose-1-phosphate because its chemical shifts are about 0.2 ppm downfield from the Pi signal (4.9 ppm). If the Pun signal is from phosphate, it represents a pH value of 7.54 ± 0.05. Therefore, it could correspond to signals of Pi in mitochondria. However, patients with critical limb ischemia have rather few mitochondria and so the Pun signal probably originates from interstitia. Our data suggest that the increased Pun signal observed in patients with the diabetic foot syndrome is a biomarker of severe muscular damage.
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Affiliation(s)
- Petr Sedivy
- MR Unit, Department of Diagnostic and Interventional Radiology, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Monika Dezortova
- MR Unit, Department of Diagnostic and Interventional Radiology, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Miloslav Drobny
- MR Unit, Department of Diagnostic and Interventional Radiology, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Michal Dubsky
- Department of Diabetology, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Tereza Dusilova
- MR Unit, Department of Diagnostic and Interventional Radiology, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Jan Kovar
- Experimental Medicine Centre, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Milan Hajek
- MR Unit, Department of Diagnostic and Interventional Radiology, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
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Metformin Regulates the Expression of SK2 and SK3 in the Atria of Rats With Type 2 Diabetes Mellitus Through the NOX4/p38MAPK Signaling Pathway. J Cardiovasc Pharmacol 2019; 72:205-213. [PMID: 30188871 DOI: 10.1097/fjc.0000000000000615] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
We previously found that metformin regulates the ion current conducted by the small conductance calcium-activated potassium channels (SK channels) in the atria of rats with type 2 diabetes mellitus (T2DM) as well as the mRNA and protein expression of the SK2 and SK3 subtypes of SK channels. In this study, we hypothesized that the nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4)/p38 mitogen-activated protein kinase (p38MAPK) signaling pathway was involved in the metformin-mediated regulation of SK2 and SK3 expression in the atria of rats with T2DM. We randomly divided Wistar rats into the control group, the untreated T2DM group, the metformin-treated group, the group receiving subcutaneous injections of the nicotinamide adenine dinucleotide phosphate oxidase (NOX) inhibitor diphenyleneiodonium (DPI), and the group receiving tail vein injections of the p38MAPK agonist anisomycin. Real-time polymerase chain reaction, Western blot, and immunohistochemistry were applied to examine the expression levels of SK2, SK3, NOX4, and phospho-p38MAPK (p-p38MAPK) mRNAs and proteins in the atrial tissue of relevant groups. We observed that the expression levels of NOX4 mRNA and protein and p-p38MAPK protein were significantly elevated in the atria of rats with T2DM compared with the control group. In addition, SK2 protein expression was reduced, whereas SK3 protein expression was increased. The 8-week treatment with metformin markedly reduced the expression levels of NOX4 mRNA and protein and p-p38MAPK protein, upregulated the SK2 expression, and downregulated the SK3 expression. Tail vein injection with anisomycin significantly increased the p-p38MAPK expression while further inhibiting the expression of SK2 and enhancing the expression of SK3. Subcutaneous injection with DPI considerably inhibited the expression of NOX4, further enhanced the expression of SK2 and suppressed the expression of SK3. In addition, subcutaneous injection with DPI significantly suppressed the phosphorylation of p38MAPK. In conclusion, the NOX4/p38MAPK signaling pathway mediates the downregulation of SK2 and the upregulation of SK3 in the atria of rats with T2DM. Long-term metformin treatment upregulates SK2 protein expression and downregulates SK3 protein expression by inhibiting the NOX4/p38MAPK signaling pathway.
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van de Weijer T, Schrauwen-Hinderling VB. Application of Magnetic Resonance Spectroscopy in metabolic research. Biochim Biophys Acta Mol Basis Dis 2019; 1865:741-748. [DOI: 10.1016/j.bbadis.2018.09.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2018] [Revised: 09/08/2018] [Accepted: 09/10/2018] [Indexed: 02/08/2023]
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Ren J, Sherry AD, Malloy CR. Modular 31 P wideband inversion transfer for integrative analysis of adenosine triphosphate metabolism, T 1 relaxation and molecular dynamics in skeletal muscle at 7T. Magn Reson Med 2019; 81:3440-3452. [PMID: 30793793 DOI: 10.1002/mrm.27686] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 01/16/2019] [Accepted: 01/18/2019] [Indexed: 12/13/2022]
Abstract
PURPOSE For efficient and integrative analysis of de novo adenosine triphosphate (ATP) synthesis, creatine-kinase-mediated ATP synthesis, T1 relaxation time, and ATP molecular motion dynamics in human skeletal muscle at rest. METHODS Four inversion-transfer modules differing in center inversion frequency were combined to generate amplified magnetization transfer (MT) effects in targeted MT pathways, including Pi ↔ γ-ATP, PCr ↔ γ-ATP, and 31 Pγ(α)ATP ↔ 31 PβATP . MT effects from both forward and reverse exchange kinetic pathways were acquired to reduce potential bias and confounding factors in integrated data analysis. RESULTS Kinetic data collected using 4 wideband inversion modules (8 minutes each) yielded the forward exchange rate constants, kPCr →γ ATP = 0.31 ± 0.05 s-1 and kPi →γ ATP = 0.064 ± 0.012 s-1 , and the reverse exchange rate constants, kγATP→Pi = 0.034 ± 0.006 s-1 and kγATP→PCr = 1.37 ± 0.22 s-1 , respectively. The cross-relaxation rate constant, σγ(α) ↔ βATP was -0.20 ± 0.03 s-1 , corresponding to ATP rotational correlation time τc of 0.8 ± 0.1 × 10-7 seconds. The intrinsic T1 relaxation times were Pi (9.2 ± 1.4 seconds), PCr (6.2 ± 0.4 seconds), γ-ATP (1.8 ± 0.1 seconds), α-ATP (1.4 ± 0.1 seconds), and β-ATP (1.1 ± 0.1 seconds). Muscle ATP T1 values were found to be significantly longer than those previously measured in the brain using a similar method. CONCLUSION A combination of multiple inversion transfer modules provides a comprehensive and integrated analysis of ATP metabolism and molecular motion dynamics. This relatively fast technique could be potentially useful for studying metabolic disorders in skeletal muscle.
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Affiliation(s)
- Jimin Ren
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas.,Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - A Dean Sherry
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas.,Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas.,Department of Chemistry, University of Texas at Dallas, Richardson, Texas
| | - Craig R Malloy
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas.,Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas.,Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas.,VA North Texas Health Care System, Dallas, Texas
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Wang CY, Liu Y, Huang S, Griswold MA, Seiberlich N, Yu X. 31 P magnetic resonance fingerprinting for rapid quantification of creatine kinase reaction rate in vivo. NMR IN BIOMEDICINE 2017; 30:10.1002/nbm.3786. [PMID: 28915341 PMCID: PMC5690599 DOI: 10.1002/nbm.3786] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 06/14/2017] [Accepted: 07/12/2017] [Indexed: 05/25/2023]
Abstract
The purpose of this work was to develop a 31 P spectroscopic magnetic resonance fingerprinting (MRF) method for fast quantification of the chemical exchange rate between phosphocreatine (PCr) and adenosine triphosphate (ATP) via creatine kinase (CK). A 31 P MRF sequence (CK-MRF) was developed to quantify the forward rate constant of ATP synthesis via CK ( kfCK), the T1 relaxation time of PCr ( T1PCr), and the PCr-to-ATP concentration ratio ( MRPCr). The CK-MRF sequence used a balanced steady-state free precession (bSSFP)-type excitation with ramped flip angles and a unique saturation scheme sensitive to the exchange between PCr and γATP. Parameter estimation was accomplished by matching the acquired signals to a dictionary generated using the Bloch-McConnell equation. Simulation studies were performed to examine the susceptibility of the CK-MRF method to several potential error sources. The accuracy of nonlocalized CK-MRF measurements before and after an ischemia-reperfusion (IR) protocol was compared with the magnetization transfer (MT-MRS) method in rat hindlimb at 9.4 T (n = 14). The reproducibility of CK-MRF was also assessed by comparing CK-MRF measurements with both MT-MRS (n = 17) and four angle saturation transfer (FAST) (n = 7). Simulation results showed that CK-MRF quantification of kfCK was robust, with less than 5% error in the presence of model inaccuracies including dictionary resolution, metabolite T2 values, inorganic phosphate metabolism, and B1 miscalibration. Estimation of kfCK by CK-MRF (0.38 ± 0.02 s-1 at baseline and 0.42 ± 0.03 s-1 post-IR) showed strong agreement with MT-MRS (0.39 ± 0.03 s-1 at baseline and 0.44 ± 0.04 s-1 post-IR). kfCK estimation was also similar between CK-MRF and FAST (0.38 ± 0.02 s-1 for CK-MRF and 0.38 ± 0.11 s-1 for FAST). The coefficient of variation from 20 s CK-MRF quantification of kfCK was 42% of that by 150 s MT-MRS acquisition and was 12% of that by 20 s FAST acquisition. This study demonstrates the potential of a 31 P spectroscopic MRF framework for rapid, accurate and reproducible quantification of chemical exchange rate of CK in vivo.
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Affiliation(s)
- Charlie Y. Wang
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio
| | - Yuchi Liu
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio
| | - Shuying Huang
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio
| | - Mark A. Griswold
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio
- Department of Radiology, Case Western Reserve University, Cleveland, Ohio
| | - Nicole Seiberlich
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio
- Department of Radiology, Case Western Reserve University, Cleveland, Ohio
| | - Xin Yu
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio
- Department of Radiology, Case Western Reserve University, Cleveland, Ohio
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio
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Liu Y, Gu Y, Yu X. Assessing tissue metabolism by phosphorous-31 magnetic resonance spectroscopy and imaging: a methodology review. Quant Imaging Med Surg 2017; 7:707-726. [PMID: 29312876 PMCID: PMC5756783 DOI: 10.21037/qims.2017.11.03] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 11/11/2017] [Indexed: 01/11/2023]
Abstract
Many human diseases are caused by an imbalance between energy production and demand. Magnetic resonance spectroscopy (MRS) and magnetic resonance imaging (MRI) provide the unique opportunity for in vivo assessment of several fundamental events in tissue metabolism without the use of ionizing radiation. Of particular interest, phosphate metabolites that are involved in ATP generation and utilization can be quantified noninvasively by phosphorous-31 (31P) MRS/MRI. Furthermore, 31P magnetization transfer (MT) techniques allow in vivo measurement of metabolic fluxes via creatine kinase (CK) and ATP synthase. However, a major impediment for the clinical applications of 31P-MRS/MRI is the prohibitively long acquisition time and/or the low spatial resolution that are necessary to achieve adequate signal-to-noise ratio. In this review, current 31P-MRS/MRI techniques used in basic science and clinical research are presented. Recent advances in the development of fast 31P-MRS/MRI methods are also discussed.
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Affiliation(s)
- Yuchi Liu
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
| | - Yuning Gu
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
| | - Xin Yu
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
- Department of Radiology, Case Western Reserve University, Cleveland, OH, USA
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, USA
- Case Center for Imaging Research, Case Western Reserve University, Cleveland, OH, USA
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Dai Z, Shestov AA, Lai L, Locasale JW. A Flux Balance of Glucose Metabolism Clarifies the Requirements of the Warburg Effect. Biophys J 2017; 111:1088-100. [PMID: 27602736 DOI: 10.1016/j.bpj.2016.07.028] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 07/20/2016] [Accepted: 07/22/2016] [Indexed: 12/19/2022] Open
Abstract
The Warburg effect, or aerobic glycolysis, is marked by the increased metabolism of glucose to lactate in the presence of oxygen. Despite its widespread prevalence in physiology and cancer biology, the causes and consequences remain incompletely understood. Here, we show that a simple balance of interacting fluxes in glycolysis creates constraints that impose the necessary conditions for glycolytic flux to generate lactate as opposed to entering into the mitochondria. These conditions are determined by cellular redox and energy demands. By analyzing the constraints and sampling the feasible region of the model, we further study how cell proliferation rate and mitochondria-associated NADH oxidizing and ATP producing fluxes are interlinked. Together this analysis illustrates the simplicity of the origins of the Warburg effect by identifying the flux distributions that are necessary for its instantiation.
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Affiliation(s)
- Ziwei Dai
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Duke Molecular Physiology Institute, Duke Cancer Institute, Durham, North Carolina; Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Alexander A Shestov
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Luhua Lai
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Jason W Locasale
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Duke Molecular Physiology Institute, Duke Cancer Institute, Durham, North Carolina.
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Valkovič L, Chmelík M, Krššák M. In-vivo 31P-MRS of skeletal muscle and liver: A way for non-invasive assessment of their metabolism. Anal Biochem 2017; 529:193-215. [PMID: 28119063 PMCID: PMC5478074 DOI: 10.1016/j.ab.2017.01.018] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 01/13/2017] [Accepted: 01/19/2017] [Indexed: 01/18/2023]
Abstract
In addition to direct assessment of high energy phosphorus containing metabolite content within tissues, phosphorus magnetic resonance spectroscopy (31P-MRS) provides options to measure phospholipid metabolites and cellular pH, as well as the kinetics of chemical reactions of energy metabolism in vivo. Even though the great potential of 31P-MR was recognized over 30 years ago, modern MR systems, as well as new, dedicated hardware and measurement techniques provide further opportunities for research of human biochemistry. This paper presents a methodological overview of the 31P-MR techniques that can be used for basic, physiological, or clinical research of human skeletal muscle and liver in vivo. Practical issues of 31P-MRS experiments and examples of potential applications are also provided. As signal localization is essential for liver 31P-MRS and is important for dynamic muscle examinations as well, typical localization strategies for 31P-MR are also described.
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Affiliation(s)
- Ladislav Valkovič
- High-field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria; Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, Oxford, United Kingdom; Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia.
| | - 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; Institute for Clinical Molecular MRI in Musculoskeletal System, Karl Landsteiner Society, 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
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12
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Ren J, Sherry AD, Malloy CR. Efficient 31 P band inversion transfer approach for measuring creatine kinase activity, ATP synthesis, and molecular dynamics in the human brain at 7 T. Magn Reson Med 2016; 78:1657-1666. [PMID: 27868234 DOI: 10.1002/mrm.26560] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Revised: 10/16/2016] [Accepted: 11/03/2016] [Indexed: 01/28/2023]
Abstract
PURPOSE To develop an efficient 31 P magnetic resonance spectroscopy (MRS) method for measuring creatine kinase (CK) activity, adenosine triphosphate (ATP) synthesis, and motion dynamics in the human brain at 7 Tesla (T). METHODS Three band inversion modules differing in center frequency were used to induce magnetization transfer (MT) effect in three exchange pathways: (i) CK-mediated reaction PCr → γ-ATP; (ii) de novo ATP synthesis Pi → γ-ATP; and (iii) ATP intramolecular 31 P-31 P cross-relaxation γ-(α-) ↔ β-ATP. The resultant MT data were analyzed using a 5-pool model in the format of magnetization matrix according to Bloch-McConnell-Solomon formalism. RESULTS With a repetition time (TR) of 4 s, the scan time for each module was approximately 8 min. The rate constants were kPCr → γATP 0.38 ± 0.02 s-1 , kPi → γATP 0.19 ± 0.02 s-1 , and σγ(α) ↔ βATP 0.19 ± 0.04 s-1 , corresponding to ATP rotation correlation time τc (0.8 ± 0.2) ·10-7 s. The T1 relaxation times were Pi 7.26 ± 1.76 s, PCr 5.99 ± 0.58 s, γ-ATP 0.98 ± 0.07 s, α-ATP 0.95 ± 0.04 s, and β-ATP 0.68 ± 0.03 s. CONCLUSION Short-TR band inversion modules provide a time-efficient way of measuring brain ATP metabolism and could be useful in studying metabolic disorders in brain diseases. Magn Reson Med 78:1657-1666, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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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
| | - A Dean Sherry
- 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.,Department of Chemistry, University of Texas at Dallas, Richardson, Texas, USA
| | - Craig R Malloy
- 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.,Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,VA North Texas Health Care System, Dallas, Texas, USA
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13
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Layec G, Gifford JR, Trinity JD, Hart CR, Garten RS, Park SY, Le Fur Y, Jeong EK, Richardson RS. Accuracy and precision of quantitative 31P-MRS measurements of human skeletal muscle mitochondrial function. Am J Physiol Endocrinol Metab 2016; 311:E358-66. [PMID: 27302751 PMCID: PMC5005269 DOI: 10.1152/ajpendo.00028.2016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 06/06/2016] [Indexed: 11/22/2022]
Abstract
Although theoretically sound, the accuracy and precision of (31)P-magnetic resonance spectroscopy ((31)P-MRS) approaches to quantitatively estimate mitochondrial capacity are not well documented. Therefore, employing four differing models of respiratory control [linear, kinetic, and multipoint adenosine diphosphate (ADP) and phosphorylation potential], this study sought to determine the accuracy and precision of (31)P-MRS assessments of peak mitochondrial adenosine-triphosphate (ATP) synthesis rate utilizing directly measured peak respiration (State 3) in permeabilized skeletal muscle fibers. In 23 subjects of different fitness levels, (31)P-MRS during a 24-s maximal isometric knee extension and high-resolution respirometry in muscle fibers from the vastus lateralis was performed. Although significantly correlated with State 3 respiration (r = 0.72), both the linear (45 ± 13 mM/min) and phosphorylation potential (47 ± 16 mM/min) models grossly overestimated the calculated in vitro peak ATP synthesis rate (P < 0.05). Of the ADP models, the kinetic model was well correlated with State 3 respiration (r = 0.72, P < 0.05), but moderately overestimated ATP synthesis rate (P < 0.05), while the multipoint model, although being somewhat less well correlated with State 3 respiration (r = 0.55, P < 0.05), most accurately reflected peak ATP synthesis rate. Of note, the PCr recovery time constant (τ), a qualitative index of mitochondrial capacity, exhibited the strongest correlation with State 3 respiration (r = 0.80, P < 0.05). Therefore, this study reveals that each of the (31)P-MRS data analyses, including PCr τ, exhibit precision in terms of mitochondrial capacity. As only the multipoint ADP model did not overstimate the peak skeletal muscle mitochondrial ATP synthesis, the multipoint ADP model is the only quantitative approach to exhibit both accuracy and precision.
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Affiliation(s)
- Gwenael Layec
- Department of Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah; Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah;
| | - Jayson R Gifford
- Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah; Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah
| | - Joel D Trinity
- Department of Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah; Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah
| | - Corey R Hart
- Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah; Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah
| | - Ryan S Garten
- Department of Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah; Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah
| | - Song Y Park
- Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah; Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah
| | - Yann Le Fur
- Aix-Marseille Université, Centre national de la recherche scientifique, Center for Magnetic Resonance in Biology and Medicine, Unité Mixte de Recherche 7339, Marseille, France
| | - Eun-Kee Jeong
- Department of Radiology and Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah; and
| | - Russell S Richardson
- Department of Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah; Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah; Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah
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14
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Pouymayou B, Buehler T, Kreis R, Boesch C. Test-retest analysis of multiple 31 P magnetization exchange pathways using asymmetric adiabatic inversion. Magn Reson Med 2016; 78:33-39. [PMID: 27455454 DOI: 10.1002/mrm.26337] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 05/31/2016] [Accepted: 06/17/2016] [Indexed: 01/08/2023]
Abstract
PURPOSE A 31 P-MR inversion transfer (IT) method with a short adiabatic inversion pulse is proposed and its test-retest reliability was evaluated for two spectral fitting strategies. METHODS Assessment in a test-retest design (3 Tesla, vastus muscles, 12 healthy volunteers, 14 inversion times, 22 ms asymmetric adiabatic inversion pulse, adiabatic excitation); spectral fitting in Fitting Tool for Interrelated Arrays of Datasets (FitAID) and Java Magnetic Resonance User Interface (jMRUI); least squares solution of the Bloch-McConnell-Solomon matrix formalism including all 14 measured time-points with equal weighting. RESULTS The cohort averages of k[PCr→γ-ATP] (phosphocreatine, PCr; adenosine triphosphate, ATP) are 0.246 ± 0.050s-1 versus 0.254 ± 0.050s-1 , and k[Pi→γ-ATP] 0.086 ± 0.033s-1 versus 0.066 ± 0.034s-1 (average ± standard deviation, jMRUI versus FitAID). Coefficients of variation of the differences between test and retest are lowest (9.5%) for k[PCr→γ-ATP] fitted in FitAID, larger (15.2%) for the fit in jMRUI, and considerably larger for k[Pi→γ-ATP] fitted in FitAID (43.4%) or jMRUI (47.9%). The beginning of the IT effect can be observed with magnetizations above 92% for noninverted lines while inversion of the ATP resonances is better than -72%. CONCLUSION The performance of the asymmetric adiabatic pulse allows an accurate observation of IT effects even in the early phase; the least squares fit of the Bloch-McConnell-Solomon matrix formalism is robust; and the type of spectral fitting can influence the results significantly. Magn Reson Med 78:33-39, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Bertrand Pouymayou
- Department of Clinical Research and Department of Radiology, University of Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Tania Buehler
- Department of Clinical Research and Department of Radiology, University of Bern, Switzerland
| | - Roland Kreis
- Department of Clinical Research and Department of Radiology, University of Bern, Switzerland
| | - Chris Boesch
- Department of Clinical Research and Department of Radiology, University of Bern, Switzerland
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15
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Ren J, Sherry AD, Malloy CR. Band inversion amplifies 31 P- 31 P nuclear overhauser effects: Relaxation mechanism and dynamic behavior of ATP in the human brain by 31 P MRS at 7 T. Magn Reson Med 2016; 77:1409-1418. [PMID: 27060982 DOI: 10.1002/mrm.26236] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 02/22/2016] [Accepted: 03/14/2016] [Indexed: 01/07/2023]
Abstract
PURPOSE To develop an improved method to measure the 31 P nuclear Overhauser effect (NOE) for evaluation of adenosine triphosphate (ATP) dynamics in terms of correlation time (τc ), and contribution of dipole-dipole (DD) and chemical shift anisotropy (CSA) mechanisms to T1 relaxation of ATP in human brain. METHODS The NOE of ATP in human brain was evaluated by monitoring changes in magnetization in the β-ATP signal following a band inversion of all downfield 31 P resonances. The magnetization changes observed were analyzed using the Bloch-McConnell-Solomon formulation to evaluate the relaxation and motion dynamic parameters that describe interactions of ATP with cellular solids in human brain tissue. RESULTS The maximal transient NOE, observed as a reduction in the β-ATP signal, was 24 ± 2% upon band inversion of γ- and α-ATP, which is 2-3-fold higher than achievable by frequency-selective inversion of either γ- or α-ATP. The rate of 31 P-31 P cross relaxation (0.21 ± 0.02 s-1 ) led to a τc value of (9.1 ± 0.8) × 10-8 s for ATP in human brain. The T1 relaxation of β-ATP is dominated by CSA over the DD mechanism (60%: 40%). CONCLUSIONS The band inversion method proved effective in amplifying 31 P NOE, and thus facilitating ATP τc and relaxation measurements. This technique renders ATP a potentially useful reporter molecule for cellular environments. Magn Reson Med 77:1409-1418, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Jimin Ren
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, 75390.,Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, 75390
| | - A Dean Sherry
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, 75390.,Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, 75390.,Department of Chemistry, University of Texas at Dallas, Richardson, TX, 75080
| | - Craig R Malloy
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, 75390.,Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, 75390.,Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, 75390.,VA North Texas Health Care System, Dallas, TX, 75216
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16
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Sleigh A, Savage DB, Williams GB, Porter D, Carpenter TA, Brindle KM, Kemp GJ. 31P magnetization transfer measurements of Pi→ATP flux in exercising human muscle. J Appl Physiol (1985) 2016; 120:649-56. [PMID: 26744504 PMCID: PMC4796179 DOI: 10.1152/japplphysiol.00871.2015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 01/02/2016] [Indexed: 11/22/2022] Open
Abstract
Fundamental criticisms have been made over the use of (31)P magnetic resonance spectroscopy (MRS) magnetization transfer estimates of inorganic phosphate (Pi)→ATP flux (VPi-ATP) in human resting skeletal muscle for assessing mitochondrial function. Although the discrepancy in the magnitude of VPi-ATP is now acknowledged, little is known about its metabolic determinants. Here we use a novel protocol to measure VPi-ATP in human exercising muscle for the first time. Steady-state VPi-ATP was measured at rest and over a range of exercise intensities and compared with suprabasal oxidative ATP synthesis rates estimated from the initial rates of postexercise phosphocreatine resynthesis (VATP). We define a surplus Pi→ATP flux as the difference between VPi-ATP and VATP. The coupled reactions catalyzed by the glycolytic enzymes GAPDH and phosphoglycerate kinase (PGK) have been shown to catalyze measurable exchange between ATP and Pi in some systems and have been suggested to be responsible for this surplus flux. Surplus VPi-ATP did not change between rest and exercise, even though the concentrations of Pi and ADP, which are substrates for GAPDH and PGK, respectively, increased as expected. However, involvement of these enzymes is suggested by correlations between absolute and surplus Pi→ATP flux, both at rest and during exercise, and the intensity of the phosphomonoester peak in the (31)P NMR spectrum. This peak includes contributions from sugar phosphates in the glycolytic pathway, and changes in its intensity may indicate changes in downstream glycolytic intermediates, including 3-phosphoglycerate, which has been shown to influence the exchange between ATP and Pi catalyzed by GAPDH and PGK.
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Affiliation(s)
- Alison Sleigh
- Wolfson Brain Imaging Centre, University of Cambridge School of Clinical Medicine, Cambridge Biomedical Campus, United Kingdom; National Institute for Health Research/Wellcome Trust Clinical Research Facility at Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, United Kingdom;
| | - David B Savage
- University of Cambridge Metabolic Research Laboratories, Wellcome Trust-Medical Research Council Institute of Metabolic Science, Cambridge Biomedical Campus, United Kingdom
| | - Guy B Williams
- Wolfson Brain Imaging Centre, University of Cambridge School of Clinical Medicine, Cambridge Biomedical Campus, United Kingdom
| | - David Porter
- Fraunhofer MEVIS, Institute for Medical Image Computing, Bremen, Germany
| | - T Adrian Carpenter
- Wolfson Brain Imaging Centre, University of Cambridge School of Clinical Medicine, Cambridge Biomedical Campus, United Kingdom
| | - Kevin M Brindle
- Department of Biochemistry, University of Cambridge, United Kingdom; Cancer Research UK Cambridge Institute, Li Ka Shing Centre, University of Cambridge, Cambridge Biomedical Campus, United Kingdom
| | - Graham J Kemp
- Magnetic Resonance and Image Analysis Research Centre, University of Liverpool, United Kingdom; and Department of Musculoskeletal Biology and MRC - Arthritis Research UK Centre for Integrated research into Musculoskeletal Ageing, Institute of Ageing and Chronic Disease, University of Liverpool, United Kingdom
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17
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Wessels B, van den Broek NMA, Ciapaite J, Houten SM, Wanders RJA, Nicolay K, Prompers JJ. Carnitine supplementation in high-fat diet-fed rats does not ameliorate lipid-induced skeletal muscle mitochondrial dysfunction in vivo. Am J Physiol Endocrinol Metab 2015; 309:E670-8. [PMID: 26286868 DOI: 10.1152/ajpendo.00144.2015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 08/17/2015] [Indexed: 12/24/2022]
Abstract
Muscle lipid overload and the associated accumulation of lipid intermediates play an important role in the development of insulin resistance. Carnitine insufficiency is a common feature of insulin-resistant states and might lead to incomplete fatty acid oxidation and impaired export of lipid intermediates out of the mitochondria. The aim of the present study was to test the hypothesis that carnitine supplementation reduces high-fat diet-induced lipotoxicity, improves muscle mitochondrial function, and ameliorates insulin resistance. Wistar rats were fed either normal chow or a high-fat diet for 15 wk. One group of high-fat diet-fed rats was supplemented with 300 mg·kg(-1)·day(-1) L-carnitine during the last 8 wk. Muscle mitochondrial function was measured in vivo by (31)P magnetic resonance spectroscopy (MRS) and ex vivo by high-resolution respirometry. Muscle lipid status was determined by (1)H MRS (intramyocellular lipids) and tandem mass spectrometry (acylcarnitines). High-fat diet feeding induced insulin resistance and was associated with decreases in muscle and blood free carnitine, elevated levels of muscle lipids and acylcarnitines, and an increased number of muscle mitochondria that showed an improved capacity to oxidize fat-derived substrates when tested ex vivo. This was, however, not accompanied by an increase in muscle oxidative capacity in vivo, indicating that in vivo mitochondrial function was compromised. Despite partial normalization of muscle and blood free carnitine content, carnitine supplementation did not induce improvements in muscle lipid status, in vivo mitochondrial function, or insulin sensitivity. Carnitine insufficiency, therefore, does not play a major role in high-fat diet-induced muscle mitochondrial dysfunction in vivo.
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Affiliation(s)
- Bart Wessels
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, the Netherlands; and
| | - Nicole M A van den Broek
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, the Netherlands; and
| | - Jolita Ciapaite
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, the Netherlands; and
| | - Sander M Houten
- Laboratory Genetic Metabolic Diseases, Departments of Pediatrics and Clinical Chemistry, Academic Medical Center, Amsterdam, the Netherlands
| | - Ronald J A Wanders
- Laboratory Genetic Metabolic Diseases, Departments of Pediatrics and Clinical Chemistry, Academic Medical Center, Amsterdam, the Netherlands
| | - Klaas Nicolay
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, the Netherlands; and
| | - Jeanine J Prompers
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, the Netherlands; and
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18
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Buehler T, Kreis R, Boesch C. Comparison of (31)P saturation and inversion magnetization transfer in human liver and skeletal muscle using a clinical MR system and surface coils. NMR IN BIOMEDICINE 2015; 28:188-199. [PMID: 25483778 DOI: 10.1002/nbm.3242] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 11/07/2014] [Accepted: 11/10/2014] [Indexed: 06/04/2023]
Abstract
(31)P MRS magnetization transfer ((31)P-MT) experiments allow the estimation of exchange rates of biochemical reactions, such as the creatine kinase equilibrium and adenosine triphosphate (ATP) synthesis. Although various (31)P-MT methods have been successfully used on isolated organs or animals, their application on humans in clinical scanners poses specific challenges. This study compared two major (31)P-MT methods on a clinical MR system using heteronuclear surface coils. Although saturation transfer (ST) is the most commonly used (31)P-MT method, sequences such as inversion transfer (IT) with short pulses might be better suited for the specific hardware and software limitations of a clinical scanner. In addition, small NMR-undetectable metabolite pools can transfer MT to NMR-visible pools during long saturation pulses, which is prevented with short pulses. (31)P-MT sequences were adapted for limited pulse length, for heteronuclear transmit-receive surface coils with inhomogeneous B1 , for the need for volume selection and for the inherently low signal-to-noise ratio (SNR) on a clinical 3-T MR system. The ST and IT sequences were applied to skeletal muscle and liver in 10 healthy volunteers. Monte-Carlo simulations were used to evaluate the behavior of the IT measurements with increasing imperfections. In skeletal muscle of the thigh, ATP synthesis resulted in forward reaction constants (k) of 0.074 ± 0.022 s(-1) (ST) and 0.137 ± 0.042 s(-1) (IT), whereas the creatine kinase reaction yielded 0.459 ± 0.089 s(-1) (IT). In the liver, ATP synthesis resulted in k = 0.267 ± 0.106 s(-1) (ST), whereas the IT experiment yielded no consistent results. ST results were close to literature values; however, the IT results were either much larger than the corresponding ST values and/or were widely scattered. To summarize, ST and IT experiments can both be implemented on a clinical body scanner with heteronuclear transmit-receive surface coils; however, ST results are much more robust against experimental imperfections than the current implementation of IT.
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Affiliation(s)
- Tania Buehler
- Departments of Clinical Research and Radiology, University of Bern, Switzerland
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19
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Kemp GJ, Ahmad RE, Nicolay K, Prompers JJ. Quantification of skeletal muscle mitochondrial function by 31P magnetic resonance spectroscopy techniques: a quantitative review. Acta Physiol (Oxf) 2015; 213:107-44. [PMID: 24773619 DOI: 10.1111/apha.12307] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2013] [Revised: 12/30/2013] [Accepted: 04/23/2014] [Indexed: 12/16/2022]
Abstract
Magnetic resonance spectroscopy (MRS) can give information about cellular metabolism in vivo which is difficult to obtain in other ways. In skeletal muscle, non-invasive (31) P MRS measurements of the post-exercise recovery kinetics of pH, [PCr], [Pi] and [ADP] contain valuable information about muscle mitochondrial function and cellular pH homeostasis in vivo, but quantitative interpretation depends on understanding the underlying physiology. Here, by giving examples of the analysis of (31) P MRS recovery data, by some simple computational simulation, and by extensively comparing data from published studies using both (31) P MRS and invasive direct measurements of muscle O2 consumption in a common analytical framework, we consider what can be learnt quantitatively about mitochondrial metabolism in skeletal muscle using MRS-based methodology. We explore some technical and conceptual limitations of current methods, and point out some aspects of the physiology which are still incompletely understood.
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Affiliation(s)
- G. J. Kemp
- Department of Musculoskeletal Biology, and Magnetic Resonance and Image Analysis Research Centre; University of Liverpool; Liverpool UK
| | - R. E. Ahmad
- Department of Musculoskeletal Biology, and Magnetic Resonance and Image Analysis Research Centre; University of Liverpool; Liverpool UK
| | - K. Nicolay
- Biomedical NMR; Department of Biomedical Engineering; Eindhoven University of Technology; Eindhoven the Netherlands
| | - J. J. Prompers
- Biomedical NMR; Department of Biomedical Engineering; Eindhoven University of Technology; Eindhoven the Netherlands
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20
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Prompers JJ, Wessels B, Kemp GJ, Nicolay K. MITOCHONDRIA: investigation of in vivo muscle mitochondrial function by 31P magnetic resonance spectroscopy. Int J Biochem Cell Biol 2014; 50:67-72. [PMID: 24569118 DOI: 10.1016/j.biocel.2014.02.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Revised: 02/06/2014] [Accepted: 02/16/2014] [Indexed: 01/06/2023]
Abstract
The most important function of mitochondria is the production of energy in the form of ATP. The socio-economic impact of human diseases that affect skeletal muscle mitochondrial function is growing, and improving their clinical management critically depends on the development of non-invasive assays to assess mitochondrial function and monitor the effects of interventions. 31P magnetic resonance spectroscopy provides two approaches that have been used to assess in vivo ATP synthesis in skeletal muscle: measuring Pi→ATP exchange flux using saturation transfer in resting muscle, and measuring phosphocreatine recovery kinetics after exercise. However, Pi→ATP exchange does not represent net mitochondrial ATP synthesis flux and has no simple relationship with mitochondrial function. Post-exercise phosphocreatine recovery kinetics, on the other hand, yield reliable measures of muscle mitochondrial capacity in vivo, whose ability to define the site of functional defects is enhanced by combination with other non-invasive techniques.
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Affiliation(s)
- Jeanine J Prompers
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.
| | - Bart Wessels
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Graham J Kemp
- Department of Musculoskeletal Biology and Magnetic Resonance & Image Analysis Research Centre, University of Liverpool, UK
| | - Klaas Nicolay
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
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21
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In vivo (31)P NMR spectroscopy assessment of skeletal muscle bioenergetics after spinal cord contusion in rats. Eur J Appl Physiol 2014; 114:847-58. [PMID: 24399112 DOI: 10.1007/s00421-013-2810-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Accepted: 11/29/2013] [Indexed: 10/25/2022]
Abstract
PURPOSE Muscle paralysis after spinal cord injury leads to muscle atrophy, enhanced muscle fatigue, and increased energy demands for functional activities. Phosphorus magnetic resonance spectroscopy ((31)P-MRS) offers a unique non-invasive alternative of measuring energy metabolism in skeletal muscle and is especially suitable for longitudinal investigations. We determined the impact of spinal cord contusion on in vivo muscle bioenergetics of the rat hind limb muscle using (31)P-MRS. METHODS A moderate spinal cord contusion injury (cSCI) was induced at the T8-T10 thoracic spinal segments. (31)P-MRS measurements were performed weekly in the rat hind limb muscles for 3 weeks. Spectra were acquired in a Bruker 11 T/470 MHz spectrometer using a 31P surface coil. The sciatic nerve was electrically stimulated by subcutaneous needle electrodes. Spectra were acquired at rest (5 min), during stimulation (6 min), and recovery (20 min). Phosphocreatine (PCr) depletion rates and the pseudo first-order rate constant for PCr recovery (k PCr) were determined. The maximal rate of PCr resynthesis, the in vivo maximum oxidative capacity (V max) and oxidative adenosine triphosphate (ATP) synthesis rate (Q max) were subsequently calculated. RESULTS One week after cSCI, there was a decline in the resting total creatine of the paralyzed muscle. There was a significant reduction (~24 %) in k PCr measures of the paralyzed muscle, maximum in vivo mitochondrial capacity (V max) and the maximum oxidative ATP synthesis rate (Q max) at 1 week post-cSCI. During exercise, the PCr depletion rates in the paralyzed muscle one week after injury were rapid and to a greater extent than in a healthy muscle. CONCLUSIONS Using in vivo MRS assessments, we reveal an acute oxidative metabolic defect in the paralyzed hind limb muscle. These altered muscle bioenergetics might contribute to the host of motor dysfunctions seen after cSCI.
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22
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Valkovič L, Ukropcová B, Chmelík M, Baláž M, Bogner W, Schmid AI, Frollo I, Zemková E, Klimeš I, Ukropec J, Trattnig S, Krššák M. Interrelation of 31P-MRS metabolism measurements in resting and exercised quadriceps muscle of overweight-to-obese sedentary individuals. NMR IN BIOMEDICINE 2013; 26:1714-1722. [PMID: 23949699 DOI: 10.1002/nbm.3008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Revised: 05/24/2013] [Accepted: 07/06/2013] [Indexed: 06/02/2023]
Abstract
Phosphorus magnetic resonance spectroscopy ((31)P-MRS) enables the non-invasive evaluation of muscle metabolism. Resting Pi-to-ATP flux can be assessed through magnetization transfer (MT) techniques, and maximal oxidative flux (Q(max)) can be calculated by monitoring of phosphocreatine (PCr) recovery after exercise. In this study, the muscle metabolism parameters of 13 overweight-to-obese sedentary individuals were measured with both MT and dynamic PCr recovery measurements, and the interrelation between these measurements was investigated. In the dynamic experiments, knee extensions were performed at a workload of 30% of maximal voluntary capacity, and the consecutive PCr recovery was measured in a quadriceps muscle with a time resolution of 2 s with non-localized (31)P-MRS at 3 T. Resting skeletal muscle metabolism was assessed through MT measurements of the same muscle group at 7 T. Significant linear correlations between the Q(max) and the MT parameters k(ATP) (r = 0.77, P = 0.002) and F(ATP) (r = 0.62, P = 0.023) were found in the study population. This would imply that the MT technique can possibly be used as an alternative method to assess muscle metabolism when necessary (e.g. in individuals after stroke or in uncooperative patients).
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Affiliation(s)
- Ladislav Valkovič
- MR Centre of Excellence, Department of Radiology, Medical University of Vienna, Vienna, Austria; Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovak Republic
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23
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van Oorschot JWM, Schmitz JPJ, Webb A, Nicolay K, Jeneson JAL, Kan HE. 31P MR spectroscopy and computational modeling identify a direct relation between Pi content of an alkaline compartment in resting muscle and phosphocreatine resynthesis kinetics in active muscle in humans. PLoS One 2013; 8:e76628. [PMID: 24098796 PMCID: PMC3786961 DOI: 10.1371/journal.pone.0076628] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 08/26/2013] [Indexed: 12/04/2022] Open
Abstract
The assessment of mitochondrial properties in skeletal muscle is important in clinical research, for instance in the study of diabetes. The gold standard to measure mitochondrial capacity non-invasively is the phosphocreatine (PCr) recovery rate after exercise, measured by (31)P Magnetic Resonance spectroscopy ((31)P MRS). Here, we sought to expand the evidence base for an alternative method to assess mitochondrial properties which uses (31)P MRS measurement of the Pi content of an alkaline compartment attributed to mitochondria (Pi2; as opposed to cytosolic Pi (Pi1)) in resting muscle at high magnetic field. Specifically, the PCr recovery rate in human quadriceps muscle was compared with the signal intensity of the Pi2 peak in subjects with varying mitochondrial content of the quadriceps muscle as a result of athletic training, and the results were entered into a mechanistic computational model of mitochondrial metabolism in muscle to test if the empirical relation between Pi2/Pi1 ratio and the PCr recovery was consistent with theory. Localized (31)P spectra were obtained at 7T from resting vastus lateralis muscle to measure the intensity of the Pi2 peak. In the endurance trained athletes a Pi2/Pi1 ratio of 0.07 ± 0.01 was found, compared to a significantly lower (p<0.05) Pi2/Pi1 ratio of 0.03 ± 0.01 in the normally active group. Next, PCr recovery kinetics after in magnet bicycle exercise were measured at 1.5T. For the endurance trained athletes, a time constant τPCr 12 ± 3 s was found, compared to 24 ± 5s in normally active subjects. Without any parameter optimization the computational model prediction matched the experimental data well (r(2) of 0.75). Taken together, these results suggest that the Pi2 resonance in resting human skeletal muscle observed at 7T provides a quantitative MR-based functional measure of mitochondrial density.
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Affiliation(s)
| | - Joep P. J. Schmitz
- Systems Bioinformatics, Amsterdam Institute for Molecules, Medicines and Systems (AIMMS), VU University Amsterdam, Amsterdam, The Netherlands
- Computational Biology group, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Andrew Webb
- CJ Gorter Center for High field MRI, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Klaas Nicolay
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Jeroen A. L. Jeneson
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
- Laboratory for Liver, Digestive and Metabolic Disease, University Medical Center Groningen, Groningen, The Netherlands
| | - Hermien E. Kan
- CJ Gorter Center for High field MRI, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
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24
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Larsen RG, Befroy DE, Kent-Braun JA. High-intensity interval training increases in vivo oxidative capacity with no effect on P(i)→ATP rate in resting human muscle. Am J Physiol Regul Integr Comp Physiol 2012; 304:R333-42. [PMID: 23255590 DOI: 10.1152/ajpregu.00409.2012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mitochondrial ATP production is vital for meeting cellular energy demand at rest and during periods of high ATP turnover. We hypothesized that high-intensity interval training (HIT) would increase ATP flux in resting muscle (VPi→ATP) in response to a single bout of exercise, whereas changes in the capacity for oxidative ATP production (Vmax) would require repeated bouts. Eight untrained men (27 ± 4 yr; peak oxygen uptake = 36 ± 4 ml·kg(-1)·min(-1)) performed six sessions of HIT (4-6 × 30-s bouts of all-out cycling with 4-min recovery). After standardized meals and a 10-h fast, VPi→ATP and Vmax of the vastus lateralis muscle were measured using phosphorus magnetic resonance spectroscopy at 4 Tesla. Measurements were obtained at baseline, 15 h after the first training session, and 15 h after completion of the sixth session. VPi→ATP was determined from the unidirectional flux between Pi and ATP, using the saturation transfer technique. The rate of phosphocreatine recovery (kPCr) following a maximal contraction was used to calculate Vmax. While kPCr and Vmax were unchanged after a single session of HIT, completion of six training sessions resulted in a ∼14% increase in muscle oxidative capacity (P ≤ 0.004). In contrast, neither a single nor six training sessions altered VPi→ATP (P = 0.74). This novel analysis of resting and maximal high-energy phosphate kinetics in vivo in response to HIT provides evidence that distinct aspects of human skeletal muscle metabolism respond differently to this type of training.
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Affiliation(s)
- Ryan G Larsen
- Department of Kinesiology, University of Massachusetts, Amherst, MA 01003, USA
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25
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Kaminsky P, Walker PM, Deibener J, Barbe F, Jeannesson E, Escanye JM, Dousset B, Klein M. Growth hormone potentiates thyroid hormone effects on post-exercise phosphocreatine recovery in skeletal muscle. Growth Horm IGF Res 2012; 22:240-244. [PMID: 22939217 DOI: 10.1016/j.ghir.2012.08.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Revised: 07/31/2012] [Accepted: 08/02/2012] [Indexed: 01/21/2023]
Abstract
OBJECTIVE The aim of the study was to determine the respective impact of thyroxine and growth hormone on in vivo skeletal mitochondrial function assessed via post exercise phosphocreatine recovery. DESIGN The hind leg muscles of 32 hypophysectomized rats were investigated using (31)P nuclear magnetic resonance spectroscopy at rest and during the recovery period following a non tetanic stimulation of the sciatic nerve. Each rat was supplemented with hydrocortisone and was randomly assigned to one of the 4 groups: the group Hx was maintained in hypopituitarism., the group HxT was treated with 1 μg/100g/day of thyroxine (T4), the group HxG with 0.2 IU/kg/day of recombinant human GH (rGH) and the group HxGT by both thyroxine and rGH. Inorganic phosphate (Pi), phosphocreatine (PCr) and ATP were directly measured on the spectra, permitting the calculation of the phosphorylation potential (PP). RESULTS At rest, the rats treated with rGH or T4 exhibited higher PCr levels than rats Hx. The recovery rates of PCr and PP were higher in rats treated with T4 than in T4-deprivated rats, suggesting improved mitochondrial function. The rats treated by both T4 and rGH showed higher PCr and PP recovery than those maintained in hypopituitarism or treated with T4 or rGH alone. CONCLUSIONS The study demonstrates that in contrast to T4, GH given alone in hypophysectomized rats does not improve in vivo mitochondrial oxidative metabolism. Growth hormone potentiates T4 effects on oxidative metabolism.
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Affiliation(s)
- P Kaminsky
- Pôle des Spécialités Médicales, Service de Médecine Interne, Centre Hospitalier Universitaire de Nancy, Hôpitaux de Brabois, 54500 Vandoeuvre, France.
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26
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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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27
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Wary C, Naulet T, Thibaud JL, Monnet A, Blot S, Carlier PG. Splitting of Pi and other ³¹P NMR anomalies of skeletal muscle metabolites in canine muscular dystrophy. NMR IN BIOMEDICINE 2012; 25:1160-1169. [PMID: 22354667 DOI: 10.1002/nbm.2785] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Revised: 12/16/2011] [Accepted: 01/10/2012] [Indexed: 05/27/2023]
Abstract
Many anomalies exist in the resting (31) P muscle spectra of boys with Duchenne muscular dystrophy (DMD) but few have been reported in Golden Retriever muscular dystrophy (GRMD), the closest existing animal model for DMD. Because GRMD is recommended for preclinical evaluation of therapies and quantitative outcome measures are needed, we investigated anomalies of (31) P NMRS in tibial cranial and biceps femoris muscles from 14 GRMD compared to 9 control (CONT) dogs. Alterations observed in DMD children - low phosphocreatine and high phospho-monoesters and -diesters - were all found in GRMD but increased pH was not. More surprisingly, inorganic phosphate (Pi) appeared to present a prominent splitting with an enhanced Pi(b) resonance at 0.3 ppm downfield of Pi(a) . Assuming that both resonances are Pi, the pH for Pi(a) in GRMD corresponded to a physiological intracellular pH(a) (6.97 ± 0.05), while pH(b) approached the extracellular range (7.27 ± 0.10) and correlated with pH(a) in GRMD (R(2) = 0.65). Both Pi(a) and Pi(b) were elevated compared to CONT and Pi(a) increased with age for GRMD (R(2) = 0.48, p < 0.001). Magnetisation transfer experiments between γATP and Pi were conducted to better characterise Pi pools. Equal T1 relaxation times for Pi(b) and Pi(a) did not support a mitochondrial origin of Pi(b) . We suggest that Pi(b) could originate from degenerating hypercontracted cells that have a leaky membrane and inadequate cell homeostasis and pH regulation. Pi(b) showed minimal chemical exchange in all dogs, while the exchange rate of Pi(a) was reduced in GRMD and might extraneously reflect low glycolytic activity in DMD. Taken together, the ensemble of (31) P NMRS alterations identifies muscle dysfunction and could provide useful biomarkers of therapeutic efficacy. Furthermore, among these, two might relate more specifically to dystrophic processes and merit further investigation: one is the existence of the enhanced alkaline Pi(b) pool; the other, mechanisms by which membrane disruption might increase phosphodiesters in dystrophy.
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Affiliation(s)
- Claire Wary
- NMR Laboratory, Institute of Myology, Paris, France.
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28
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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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29
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Schmid AI, Schrauwen-Hinderling VB, Andreas M, Wolzt M, Moser E, Roden M. Comparison of measuring energy metabolism by different (31) P-magnetic resonance spectroscopy techniques in resting, ischemic, and exercising muscle. Magn Reson Med 2011; 67:898-905. [PMID: 21842500 DOI: 10.1002/mrm.23095] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Alternate methods to quantify mitochondrial activity or function have been extensively used for studying insulin resistance and type 2 diabetes mellitus, namely saturation transfer and phosphocreatine (PCr) recovery. As these methods are in fact determining different parameters, this study aimed to compare saturation transfer results to PCr recovery measurements within the same group. Fifteen subjects underwent saturation transfer and ischemic exercise-recovery experiments. PCr decrease during ischemia (Q), induced by cuff inflation, served as an additional measure of resting ATP (adenosine triphosphate) production. ATP synthetic rate (fATP) measured by saturation transfer (0.234 ± 0.043 mM/s) was greater than (Q = 0.0077 ± 0.0011 mM/s), but correlated well with Q (r = 0.63 P = 0.013). Parameters of PCr recovery correlated well with fATP (Q(max,lin) : r = 0.71, P = 0.003, Q(max,ADP) : r = 0.66, P = 0.007) and Q (Q(max,lin) : r = 0.92, P = 0.000002, Q(max,ADP) : r = 0.76, P = 0.001). In conclusion, although saturation transfer yields higher ATP synthetic rates than PCr decrease during ischemia, their significant correlation indicates that fATP can be used as a marker of mitochondrial activity. The finding that both Q and fATP correlate with PCr recovery kinetics suggests that skeletal muscle with greater maximal aerobic ATP synthetic rates is also metabolically more active at rest. Magn Reson Med, 2011. © 2011 Wiley-Liss, Inc.
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Affiliation(s)
- Albrecht I Schmid
- MR Center of Excellence, Medical University of Vienna, Vienna, Austria
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30
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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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31
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Makimura H, Stanley TL, Sun N, Hrovat MI, Systrom DM, Grinspoon SK. The association of growth hormone parameters with skeletal muscle phosphocreatine recovery in adult men. J Clin Endocrinol Metab 2011; 96:817-23. [PMID: 21177784 PMCID: PMC3047233 DOI: 10.1210/jc.2010-2264] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Previous studies have suggested a relationship between GH and mitochondrial function. However, little is known about the relationship of specific GH indices and in vivo measures of mitochondrial function in humans. OBJECTIVE The objective of this study was to determine the association between GH, IGF-I, and phosphocreatine (PCr) recovery, a measure of mitochondrial function, in otherwise healthy adults. DESIGN Thirty-seven healthy men and women were studied at a single university medical center. Subjects underwent GH stimulation testing with GH releasing hormone-arginine and measurement of IGF-I. Mitochondrial function was determined by PCr recovery after submaximal exercise by (31)Phosphorous magnetic resonance spectroscopy. Subjects underwent assessment of lean and fat mass with use of dual energy X-ray absorptiometry. RESULTS There were no differences in PCr recovery between men and women (men 20.7±1.5 vs. women 24.8±1.4 mM/min; P > 0.05). IGF-I (r = 0.33; P = 0.04) was associated with PCr recovery in all subjects. Among men, IGF-I (r = 0.69; P = 0.003), peak stimulated GH (r = 0.52; P = 0.04), and GH area under the curve (AUC) (r = 0.53; P = 0.04) were significantly associated with PCr recovery. However, neither IGF-I, peak stimulated GH, nor GH AUC (all P > 0.05) were associated with PCr recovery in women. After adjusting for age, race, and physical activity, IGF-I remained significantly associated with PCr recovery (β = 0.10; P = 0.02) among men. CONCLUSIONS IGF-I, peak stimulated GH, and GH AUC are associated with skeletal muscle PCr recovery in men.
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Affiliation(s)
- Hideo Makimura
- Program in Nutritional Metabolism and Neuroendocrine Unit, Massachusetts General Hospital and Harvard Medical School, 55 Fruit Street, LON 211, Boston, Massachusetts 02114, USA.
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32
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Makimura H, Stanley TL, Sun N, Connelly JM, Hemphill LC, Hrovat MI, Systrom DM, Grinspoon SK. Increased skeletal muscle phosphocreatine recovery after sub-maximal exercise is associated with increased carotid intima-media thickness. Atherosclerosis 2010; 215:214-7. [PMID: 21185022 DOI: 10.1016/j.atherosclerosis.2010.11.037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Accepted: 11/26/2010] [Indexed: 01/24/2023]
Abstract
BACKGROUND The association between skeletal muscle mitochondrial function and CVD risk in healthy subjects is unknown. METHODS Forty subjects were evaluated for CVD risk with lipid profile, oral glucose tolerance test and measurement of carotid intima-media thickness (cIMT). Skeletal muscle mitochondrial function was determined by phosphocreatine recovery after sub-maximal exercise with (31)Phosphorous-MRS and represented as τPCr. RESULTS τPCr was positively associated with age (r=+0.41; P=0.009) and cIMT (r=+0.50; P=0.001) on univariate analyses. In multivariate regression analysis controlling for age, the association between τPCr and cIMT remained significant (β=0.003; P=0.03). This association remained significant after controlling for traditional risk factors for CVD including age, gender, tobacco use, BMI, blood pressure, cholesterol and fasting glucose in a combined model (β=0.003; P=0.04; R(2)=0.53; P=0.008 for overall model). CONCLUSIONS These data suggest a novel association between skeletal muscle τPCr and increased cIMT, independent of age or traditional CVD risk factors.
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Affiliation(s)
- Hideo Makimura
- Program in Nutritional Metabolism and Neuroendocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA.
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