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Miller JJ, Valkovič L, Kerr M, Timm KN, Watson WD, Lau JYC, Tyler A, Rodgers C, Bottomley PA, Heather LC, Tyler DJ. Rapid, B 1 -insensitive, dual-band quasi-adiabatic saturation transfer with optimal control for complete quantification of myocardial ATP flux. Magn Reson Med 2021; 85:2978-2991. [PMID: 33538063 PMCID: PMC7986077 DOI: 10.1002/mrm.28647] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 10/28/2020] [Accepted: 11/24/2020] [Indexed: 12/16/2022]
Abstract
PURPOSE Phosphorus saturation-transfer experiments can quantify metabolic fluxes noninvasively. Typically, the forward flux through the creatine kinase reaction is investigated by observing the decrease in phosphocreatine (PCr) after saturation of γ-ATP. The quantification of total ATP utilization is currently underexplored, as it requires simultaneous saturation of inorganic phosphate ( P i ) and PCr. This is challenging, as currently available saturation pulses reduce the already-low γ-ATP signal present. METHODS Using a hybrid optimal-control and Shinnar-Le Roux method, a quasi-adiabatic RF pulse was designed for the dual saturation of PCr and P i to enable determination of total ATP utilization. The pulses were evaluated in Bloch equation simulations, compared with a conventional hard-cosine DANTE saturation sequence, before being applied to perfused rat hearts at 11.7 T. RESULTS The quasi-adiabatic pulse was insensitive to a >2.5-fold variation in B 1 , producing equivalent saturation with a 53% reduction in delivered pulse power and a 33-fold reduction in spillover at the minimum effective B 1 . This enabled the complete quantification of the synthesis and degradation fluxes for ATP in 30-45 minutes in the perfused rat heart. While the net synthesis flux (4.24 ± 0.8 mM/s, SEM) was not significantly different from degradation flux (6.88 ± 2 mM/s, P = .06) and both measures are consistent with prior work, nonlinear error analysis highlights uncertainties in the Pi -to-ATP measurement that may explain a trend suggesting a possible imbalance. CONCLUSIONS This work demonstrates a novel quasi-adiabatic dual-saturation RF pulse with significantly improved performance that can be used to measure ATP turnover in the heart in vivo.
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Affiliation(s)
- Jack J Miller
- Department of Physics, University of Oxford, Oxford, UK.,Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.,Oxford Centre for Clinical Magnetic Resonance Research, John Radcliffe Hospital, Headington, Oxford, UK.,Health, Aarhus University, Aarhus, Denmark
| | - Ladislav Valkovič
- Oxford Centre for Clinical Magnetic Resonance Research, John Radcliffe Hospital, Headington, Oxford, UK.,Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Matthew Kerr
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Kerstin N Timm
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - William D Watson
- Oxford Centre for Clinical Magnetic Resonance Research, John Radcliffe Hospital, Headington, Oxford, UK
| | - Justin Y C Lau
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.,Oxford Centre for Clinical Magnetic Resonance Research, John Radcliffe Hospital, Headington, Oxford, UK
| | - Andrew Tyler
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.,Oxford Centre for Clinical Magnetic Resonance Research, John Radcliffe Hospital, Headington, Oxford, UK
| | - Christopher Rodgers
- Oxford Centre for Clinical Magnetic Resonance Research, John Radcliffe Hospital, Headington, Oxford, UK.,Wolfson Brain Imaging Centre, University of Cambridge, Oxford, UK
| | - Paul A Bottomley
- Oxford Centre for Clinical Magnetic Resonance Research, John Radcliffe Hospital, Headington, Oxford, UK.,Division of MR Research, Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Lisa C Heather
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Damian J Tyler
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.,Oxford Centre for Clinical Magnetic Resonance Research, John Radcliffe Hospital, Headington, Oxford, UK
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Stockebrand M, Sasani A, Das D, Hornig S, Hermans-Borgmeyer I, Lake HA, Isbrandt D, Lygate CA, Heerschap A, Neu A, Choe CU. A Mouse Model of Creatine Transporter Deficiency Reveals Impaired Motor Function and Muscle Energy Metabolism. Front Physiol 2018; 9:773. [PMID: 30013483 PMCID: PMC6036259 DOI: 10.3389/fphys.2018.00773] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 06/04/2018] [Indexed: 11/22/2022] Open
Abstract
Creatine serves as fast energy buffer in organs of high-energy demand such as brain and skeletal muscle. L-Arginine:glycine amidinotransferase (AGAT) and guanidinoacetate N-methyltransferase are responsible for endogenous creatine synthesis. Subsequent uptake into target organs like skeletal muscle, heart and brain is mediated by the creatine transporter (CT1, SLC6A8). Creatine deficiency syndromes are caused by defects of endogenous creatine synthesis or transport and are mainly characterized by intellectual disability, behavioral abnormalities, poorly developed muscle mass, and in some cases also muscle weakness. CT1-deficiency is estimated to be among the most common causes of X-linked intellectual disability and therefore the brain phenotype was the main focus of recent research. Unfortunately, very limited data concerning muscle creatine levels and functions are available from patients with CT1 deficiency. Furthermore, different CT1-deficient mouse models yielded conflicting results and detailed analyses of their muscular phenotype are lacking. Here, we report the generation of a novel CT1-deficient mouse model and characterized the effects of creatine depletion in skeletal muscle. HPLC-analysis showed strongly reduced total creatine levels in skeletal muscle and heart. MR-spectroscopy revealed an almost complete absence of phosphocreatine in skeletal muscle. Increased AGAT expression in skeletal muscle was not sufficient to compensate for insufficient creatine transport. CT1-deficient mice displayed profound impairment of skeletal muscle function and morphology (i.e., reduced strength, reduced endurance, and muscle atrophy). Furthermore, severely altered energy homeostasis was evident on magnetic resonance spectroscopy. Strongly reduced phosphocreatine resulted in decreased ATP/Pi levels despite an increased inorganic phosphate to ATP flux. Concerning glucose metabolism, we show increased glucose transporter type 4 expression in muscle and improved glucose clearance in CT1-deficient mice. These metabolic changes were associated with activation of AMP-activated protein kinase – a central regulator of energy homeostasis. In summary, creatine transporter deficiency resulted in a severe muscle weakness and atrophy despite different compensatory mechanisms.
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Affiliation(s)
- Malte Stockebrand
- German Center for Neurodegenerative Diseases, Bonn, Germany.,Institute for Molecular and Behavioral Neuroscience, University of Cologne, Cologne, Germany
| | - Ali Sasani
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Experimental Neuropediatrics, Department of Pediatrics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Devashish Das
- Department of Radiology, Radboud University Nijmegen Medical Center, Nijmegen, Netherlands
| | - Sönke Hornig
- Experimental Neuropediatrics, Department of Pediatrics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Irm Hermans-Borgmeyer
- Transgenic Mouse Unit, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Hannah A Lake
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, BHF Centre of Research Excellence, University of Oxford, Oxford, United Kingdom.,Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Dirk Isbrandt
- German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Craig A Lygate
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, BHF Centre of Research Excellence, University of Oxford, Oxford, United Kingdom.,Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Arend Heerschap
- Department of Radiology, Radboud University Nijmegen Medical Center, Nijmegen, Netherlands
| | - Axel Neu
- Experimental Neuropediatrics, Department of Pediatrics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Chi-Un Choe
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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Miller JJ, Ball DR, Lau AZ, Tyler DJ. Hyperpolarized ketone body metabolism in the rat heart. NMR IN BIOMEDICINE 2018; 31:e3912. [PMID: 29637642 PMCID: PMC6001529 DOI: 10.1002/nbm.3912] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 01/22/2018] [Accepted: 02/06/2018] [Indexed: 05/13/2023]
Abstract
The aim of this work was to investigate the use of 13 C-labelled acetoacetate and β-hydroxybutyrate as novel hyperpolarized substrates in the study of cardiac metabolism. [1-13 C]Acetoacetate was synthesized by catalysed hydrolysis, and both it and [1-13 C]β-hydroxybutyrate were hyperpolarized by dissolution dynamic nuclear polarization (DNP). Their metabolism was studied in isolated, perfused rat hearts. Hyperpolarized [1-13 C]acetoacetate metabolism was also studied in the in vivo rat heart in the fed and fasted states. Hyperpolarization of [1-13 C]acetoacetate and [1-13 C]β-hydroxybutyrate provided liquid state polarizations of 8 ± 2% and 3 ± 1%, respectively. The hyperpolarized T1 values for the two substrates were 28 ± 3 s (acetoacetate) and 20 ± 1 s (β-hydroxybutyrate). Multiple downstream metabolites were observed within the perfused heart, including acetylcarnitine, citrate and glutamate. In the in vivo heart, an increase in acetylcarnitine production from acetoacetate was observed in the fed state, as well as a potential reduction in glutamate. In this work, methods for the generation of hyperpolarized [1-13 C]acetoacetate and [1-13 C]β-hydroxybutyrate were investigated, and their metabolism was assessed in both isolated, perfused rat hearts and in the in vivo rat heart. These preliminary investigations show that DNP can be used as an effective in vivo probe of ketone body metabolism in the heart.
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Affiliation(s)
- Jack J. Miller
- Department of Physiology, Anatomy and GeneticsUniversity of OxfordOxfordUK
- Department of PhysicsUniversity of OxfordOxfordUK
| | - Daniel R. Ball
- Department of Physiology, Anatomy and GeneticsUniversity of OxfordOxfordUK
| | - Angus Z. Lau
- Sunnybrook Research InstituteImaging ResearchTorontoONCanada
- Department of Medical BiophysicsUniversity of TorontoTorontoONCanada
| | - Damian J. Tyler
- Department of Physiology, Anatomy and GeneticsUniversity of OxfordOxfordUK
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van Ewijk PA, Schrauwen-Hinderling VB, Bekkers SCAM, Glatz JFC, Wildberger JE, Kooi ME. MRS: a noninvasive window into cardiac metabolism. NMR IN BIOMEDICINE 2015; 28:747-66. [PMID: 26010681 DOI: 10.1002/nbm.3320] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 04/02/2015] [Accepted: 04/07/2015] [Indexed: 05/21/2023]
Abstract
A well-functioning heart requires a constant supply of a balanced mixture of nutrients to be used for the production of adequate amounts of adenosine triphosphate, which is the main energy source for most cellular functions. Defects in cardiac energy metabolism are linked to several myocardial disorders. MRS can be used to study in vivo changes in cardiac metabolism noninvasively. MR techniques allow repeated measurements, so that disease progression and the response to treatment or to a lifestyle intervention can be monitored. It has also been shown that MRS can predict clinical heart failure and death. This article focuses on in vivo MRS to assess cardiac metabolism in humans and experimental animals, as experimental animals are often used to investigate the mechanisms underlying the development of metabolic diseases. Various MR techniques, such as cardiac (31) P-MRS, (1) H-MRS, hyperpolarized (13) C-MRS and Dixon MRI, are described. A short overview of current and emerging applications is given. Cardiac MRS is a promising technique for the investigation of the relationship between cardiac metabolism and cardiac disease. However, further optimization of scan time and signal-to-noise ratio is required before broad clinical application. In this respect, the ongoing development of advanced shimming algorithms, radiofrequency pulses, pulse sequences, (multichannel) detection coils, the use of hyperpolarized nuclei and scanning at higher magnetic field strengths offer future perspective for clinical applications of MRS.
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Affiliation(s)
- Petronella A van Ewijk
- Maastricht University Medical Center, Human Biology, Maastricht, the Netherlands
- Maastricht University Medical Center, Radiology, Maastricht, the Netherlands
- Maastricht University Medical Center, NUTRIM - School for Nutrition, Toxicology and Metabolism, Maastricht, the Netherlands
| | - Vera B Schrauwen-Hinderling
- Maastricht University Medical Center, Human Biology, Maastricht, the Netherlands
- Maastricht University Medical Center, Radiology, Maastricht, the Netherlands
- Maastricht University Medical Center, NUTRIM - School for Nutrition, Toxicology and Metabolism, Maastricht, the Netherlands
| | | | - Jan F C Glatz
- Maastricht University Medical Center, Molecular Genetics, Maastricht, the Netherlands
- Maastricht University Medical Center, CARIM - Cardiovascular Research Institute Maastricht, Maastricht, the Netherlands
| | | | - M Eline Kooi
- Maastricht University Medical Center, Radiology, Maastricht, the Netherlands
- Maastricht University Medical Center, NUTRIM - School for Nutrition, Toxicology and Metabolism, Maastricht, the Netherlands
- Maastricht University Medical Center, CARIM - Cardiovascular Research Institute Maastricht, Maastricht, the Netherlands
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Ball DR, Cruickshank R, Carr CA, Stuckey DJ, Lee P, Clarke K, Tyler DJ. Metabolic imaging of acute and chronic infarction in the perfused rat heart using hyperpolarised [1-13C]pyruvate. NMR IN BIOMEDICINE 2013; 26:1441-1450. [PMID: 23775685 DOI: 10.1002/nbm.2972] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 04/07/2013] [Accepted: 04/08/2013] [Indexed: 06/02/2023]
Abstract
Hyperpolarised (13)C MRI can be used to generate metabolic images of the heart in vivo. However, there have been no similar studies performed in the isolated perfused heart. Therefore, the aim of this study was to develop a method for the creation of (13)C metabolite maps of the perfused rat heart and to demonstrate the technique in a study of acute and chronic myocardial infarction. Male Wistar rat hearts were isolated, perfused and imaged before and after occlusion of the left anterior descending (LAD) coronary artery, creating an acute infarct group. In addition, a chronic infarct group was generated from hearts which had their LAD coronary artery occluded in vivo. Four weeks later, hearts were excised, perfused and imaged to generate metabolic maps of infused pyruvate and its metabolites lactate and bicarbonate. Myocardial perfusion and energetics were assessed by first-pass perfusion imaging and (31)P MRS, respectively. In both acute and chronically infarcted hearts, perfusion was reduced to the infarct region, as revealed by reduced gadolinium influx and lower signal intensity in the hyperpolarised pyruvate images. In the acute infarct region, there were significant alterations in the lactate (increased) and bicarbonate (decreased) signal ratios. In the chronically infarcted region, there was a significant reduction in both bicarbonate and lactate signals. (31)P-derived energetics revealed a significant decrease between control and chronic infarcted hearts. Significant decreases in contractile function between control and both acute and chronic infracted hearts were also seen. In conclusion, we have demonstrated that hyperpolarised pyruvate can detect reduced perfusion in the rat heart following both acute and chronic infarction. Changes in lactate and bicarbonate ratios indicate increased anaerobic metabolism in the acute infarct, which is not observed in the chronic infarct. Thus, this study has successfully demonstrated a novel imaging approach to assess altered metabolism in the isolated perfused rat heart.
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Affiliation(s)
- Daniel R Ball
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
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Ball DR, Rowlands B, Dodd MS, Le Page L, Ball V, Carr CA, Clarke K, Tyler DJ. Hyperpolarized butyrate: a metabolic probe of short chain fatty acid metabolism in the heart. Magn Reson Med 2013; 71:1663-9. [PMID: 23798473 PMCID: PMC4238803 DOI: 10.1002/mrm.24849] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 04/25/2013] [Accepted: 05/28/2013] [Indexed: 12/13/2022]
Abstract
Purpose Butyrate, a short chain fatty acid, was studied as a novel hyperpolarized substrate for use in dynamic nuclear polarization enhanced magnetic resonance spectroscopy experiments, to define the pathways of short chain fatty acid and ketone body metabolism in real time. Methods Butyrate was polarized via the dynamic nuclear polarization process and subsequently dissolved to generate an injectable metabolic substrate. Metabolism was initially assessed in the isolated perfused rat heart, followed by evaluation in the in vivo rat heart. Results Hyperpolarized butyrate was generated with a polarization level of 7% and was shown to have a T1 relaxation time of 20 s. These physical characteristics were sufficient to enable assessment of multiple steps in its metabolism, with the ketone body acetoacetate and several tricarboxylic acid cycle intermediates observed both in vitro and in vivo. Metabolite to butyrate ratios of 0.1–0.4% and 0.5–2% were observed in vitro and in vivo respectively, similar to levels previously observed with hyperpolarized [2-13C]pyruvate. Conclusions In this study, butyrate has been demonstrated to be a suitable hyperpolarized substrate capable of revealing multi-step metabolism in dynamic nuclear polarization experiments and providing information on the metabolism of fatty acids not currently achievable with other hyperpolarized substrates. Magn Reson Med 71:1663–1669, 2014. © 2013 Wiley Periodicals, Inc.
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Affiliation(s)
- Daniel R Ball
- Cardiac Metabolism Research Group, Department of Physiology, Anatomy & Genetics, University of Oxford, Oxford, UK
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