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Lysak DH, Bermel W, Moxley-Paquette V, Michal C, Ghosh-Biswas R, Soong R, Nashman B, Lacerda A, Simpson AJ. Cutting without a Knife: A Slice-Selective 2D 1H- 13C HSQC NMR Sequence for the Analysis of Inhomogeneous Samples. Anal Chem 2023; 95:14392-14401. [PMID: 37713676 DOI: 10.1021/acs.analchem.3c02756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/17/2023]
Abstract
Nuclear magnetic resonance (NMR) is a powerful technique with applications ranging from small molecule structure elucidation to metabolomics studies of living organisms. Typically, solution-state NMR requires a homogeneous liquid, and the whole sample is analyzed as a single entity. While adequate for homogeneous samples, such an approach is limited if the composition varies as would be the case in samples that are naturally heterogeneous or layered. In complex samples such as living organisms, magnetic susceptibility distortions lead to broad 1H line shapes, and thus, the additional spectral dispersion afforded by 2D heteronuclear experiments is often required for metabolite discrimination. Here, a novel, slice-selective 2D, 1H-13C heteronuclear single quantum coherence (HSQC) sequence was developed that exclusively employs shaped pulses such that only spins in the desired volume are perturbed. In turn, this permits multiple volumes in the tube to be studied during a single relaxation delay, increasing sensitivity and throughput. The approach is first demonstrated on standards and then used to isolate specific sample/sensor elements from a microcoil array and finally study slices within a living earthworm, allowing metabolite changes to be discerned with feeding. Overall, slice-selective NMR is demonstrated to have significant potential for the study of layered and other inhomogeneous samples of varying complexity. In particular, its ability to select subelements is an important step toward developing microcoil receive-only arrays to study environmental toxicity in tiny eggs, cells, and neonates, whereas localization in larger living species could help better correlate toxin-induced biochemical responses to the physical localities or organs involved.
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Affiliation(s)
- Daniel H Lysak
- Environmental NMR Center, Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON M1C 1A4, Canada
| | - Wolfgang Bermel
- Bruker BioSpin GmbH, Rudolf-Plank-Str. 23, 76275 Ettlingen, Germany
| | - Vincent Moxley-Paquette
- Environmental NMR Center, Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON M1C 1A4, Canada
| | - Carl Michal
- Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1, Canada
| | - Rajshree Ghosh-Biswas
- Environmental NMR Center, Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON M1C 1A4, Canada
| | - Ronald Soong
- Environmental NMR Center, Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON M1C 1A4, Canada
| | - Ben Nashman
- Synex Medical, 2 Bloor Street E, Suite 310, Toronto, ON M4W 1A8,Canada
| | - Andressa Lacerda
- Synex Medical, 2 Bloor Street E, Suite 310, Toronto, ON M4W 1A8,Canada
| | - Andre J Simpson
- Environmental NMR Center, Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON M1C 1A4, Canada
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Barekatain Y, Yan VC, Arthur K, Ackroyd JJ, Khadka S, De Groot J, Huse JT, Muller FL. Robust detection of oncometabolic aberrations by 1H- 13C heteronuclear single quantum correlation in intact biological specimens. Commun Biol 2020; 3:328. [PMID: 32587392 PMCID: PMC7316726 DOI: 10.1038/s42003-020-1055-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 05/29/2020] [Indexed: 01/02/2023] Open
Abstract
Magnetic resonance (MR) spectroscopy has potential to non-invasively detect metabolites of diagnostic significance for precision oncology. Yet, many metabolites have similar chemical shifts, yielding highly convoluted 1H spectra of intact biological material and limiting diagnostic utility. Here, we show that hydrogen–carbon heteronuclear single quantum correlation (1H–13C HSQC) offers dramatic improvements in sensitivity compared to one-dimensional (1D) 13C NMR and significant signal deconvolution compared to 1D 1H spectra in intact biological settings. Using a standard NMR spectroscope with a cryoprobe but without specialized signal enhancing features such as magic angle spinning, metabolite extractions or 13C-isotopic enrichment, we obtain well-resolved 2D 1H–13C HSQC spectra in live cancer cells, in ex vivo freshly dissected xenografted tumors and resected primary tumors. This method can identify tumors with specific oncometabolite alterations such as IDH mutations by 2-hydroxyglutarate and PGD-deleted tumors by gluconate. Results suggest potential of 1H–13C HSQC as a non-invasive diagnostic in precision oncology. Barekatain et al. demonstrate that hydrogen–carbon heteronuclear single quantum correlation (HSQC) spectra, obtained using a standard NMR spectroscope, can detect tumours with specific oncometabolite alterations including IDH1 mutant glioblastoma, suggesting the feasibility of this method as a diagnostic tool.
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Affiliation(s)
- Yasaman Barekatain
- Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, Houston, TX, 77054, USA
| | - Victoria C Yan
- Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, Houston, TX, 77054, USA
| | - Kenisha Arthur
- Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, Houston, TX, 77054, USA
| | - Jeffrey J Ackroyd
- Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, Houston, TX, 77054, USA
| | - Sunada Khadka
- Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, Houston, TX, 77054, USA
| | - John De Groot
- Department of Neuro-Oncology, University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Jason T Huse
- Department of Pathology, University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Florian L Muller
- Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, Houston, TX, 77054, USA.
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Rothman DL, de Graaf RA, Hyder F, Mason GF, Behar KL, De Feyter HM. In vivo 13 C and 1 H-[ 13 C] MRS studies of neuroenergetics and neurotransmitter cycling, applications to neurological and psychiatric disease and brain cancer. NMR IN BIOMEDICINE 2019; 32:e4172. [PMID: 31478594 DOI: 10.1002/nbm.4172] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 04/30/2019] [Accepted: 05/07/2019] [Indexed: 06/10/2023]
Abstract
In the last 25 years 13 C MRS has been established as the only noninvasive method for measuring glutamate neurotransmission and cell specific neuroenergetics. Although technically and experimentally challenging 13 C MRS has already provided important new information on the relationship between neuroenergetics and neuronal function, the high energy cost of brain function in the resting state and the role of altered neuroenergetics and neurotransmitter cycling in disease. In this paper we review the metabolic and neurotransmitter pathways that can be measured by 13 C MRS and key findings on the linkage between neuroenergetics, neurotransmitter cycling, and brain function. Applications of 13 C MRS to neurological and psychiatric disease as well as brain cancer are reviewed. Recent technological developments that may help to overcome spatial resolution and brain coverage limitations of 13 C MRS are discussed.
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Affiliation(s)
- Douglas L Rothman
- Departments of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Biomedical Engineering, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
- Departments of Radiology and Biomedical Imaging, and Biomedical Engineering, Magnetic Resonance Research Center, Yale University School of Medicine, 300 Cedar Street, P.O. Box 208043, New Haven, CT, USA
| | - Robin A de Graaf
- Departments of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Biomedical Engineering, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Fahmeed Hyder
- Departments of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Biomedical Engineering, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Graeme F Mason
- Departments of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Kevin L Behar
- Department of Psychiatry, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Henk M De Feyter
- Departments of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
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4
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De Feyter HM, Herzog RI, Steensma BR, Klomp DWJ, Brown PB, Mason GF, Rothman DL, de Graaf RA. Selective proton-observed, carbon-edited (selPOCE) MRS method for measurement of glutamate and glutamine 13 C-labeling in the human frontal cortex. Magn Reson Med 2017; 80:11-20. [PMID: 29134686 DOI: 10.1002/mrm.27003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 10/02/2017] [Accepted: 10/20/2017] [Indexed: 11/10/2022]
Abstract
PURPOSE 13 C magnetic resonance spectroscopy (MRS) in combination with infusion of 13 C-labeled substrates has led to unique insights into human brain metabolism and neurotransmitter cycling. However, the low sensitivity of direct 13 C MRS and high radiofrequency power requirements has limited 13 C MRS studies to predominantly data acquisition in large volumes of the occipital cortex. The purpose of this study is to develop an MRS technique for localized detection of 13 C-labeling of glutamate and glutamine in the human frontal lobe. METHODS We used an indirect (1 H-[13 C]), proton-observed, carbon-edited MRS sequence (selPOCE) for detection of 13 C-labeled metabolites in relatively small volumes located in the frontal lobe at 4 T. The SelPOCE method allows for selective and separate detection of glutamate and glutamine resonances, which significantly overlap at magnetic field strengths used for clinical MRI. RESULTS Phantom data illustrate how selPOCE can be tuned to selectively detect 13 C labeling in different metabolites. Three-dimensional specific absorption rate simulations of radiofrequency power deposition show that the selPOCE method operates comfortably within the global and local Food and Drug Administration specific absorption rate guidelines. In vivo selPOCE data are presented, which were acquired from a 45-mL volume in the frontal lobe of healthy subjects. The in vivo data show the time-dependent 13 C-labeling of glutamate and glutamine during intravenous infusion of [1-13 C]-glucose. Metrics describing spectral fitting quality of the glutamate and glutamine resonances are reported. CONCLUSIONS The SelPOCE sequence allows the detection of 13 C-labeling in glutamate and glutamine from a relatively small volume in the human frontal lobe at low radiofrequency power requirements. Magn Reson Med 80:11-20, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Henk M De Feyter
- Department of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Raimund I Herzog
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Bart R Steensma
- Department of Radiology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Dennis W J Klomp
- Department of Radiology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Peter B Brown
- Department of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Graeme F Mason
- Department of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Douglas L Rothman
- Department of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA.,Department of Biomedical Engineering, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Robin A de Graaf
- Department of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA.,Department of Biomedical Engineering, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
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5
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Chen H, De Feyter HM, Brown PB, Rothman DL, Cai S, de Graaf RA. Comparison of direct 13C and indirect 1H-[ 13C] MR detection methods for the study of dynamic metabolic turnover in the human brain. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 283:33-44. [PMID: 28869920 DOI: 10.1016/j.jmr.2017.08.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 08/02/2017] [Accepted: 08/10/2017] [Indexed: 06/07/2023]
Abstract
A wide range of direct 13C and indirect 1H-[13C] MR detection methods exist to probe dynamic metabolic pathways in the human brain. Choosing an optimal detection method is difficult as sequence-specific features regarding spatial localization, broadband decoupling, spectral resolution, power requirements and sensitivity complicate a straightforward comparison. Here we combine density matrix simulations with experimentally determined values for intrinsic 1H and 13C sensitivity, T1 and T2 relaxation and transmit efficiency to allow selection of an optimal 13C MR detection method for a given application and magnetic field. The indirect proton-observed, carbon-edited (POCE) detection method provides the highest accuracy at reasonable RF power deposition both at 4T and 7T. The various polarization transfer methods all have comparable performances, but may become infeasible at 7T due to the high RF power deposition. 2D MR methods have limited value for the metabolites considered (primarily glutamate, glutamine and γ-amino butyric acid (GABA)), but may prove valuable when additional information can be extracted, such as isotopomers or lipid composition. While providing the lowest accuracy, the detection of non-protonated carbons is the simplest to implement with the lowest RF power deposition. The magnetic field homogeneity is one of the most important parameters affecting the detection accuracy for all metabolites and all acquisition methods.
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Affiliation(s)
- Hao Chen
- Magnetic Resonance Research Center, Department of Radiology and Biomedical Imaging, Yale University, School of Medicine, New Haven, CT, USA; Department of Electronic Science, Xiamen University, Xiamen, Fujian, China
| | - Henk M De Feyter
- Magnetic Resonance Research Center, Department of Radiology and Biomedical Imaging, Yale University, School of Medicine, New Haven, CT, USA
| | - Peter B Brown
- Magnetic Resonance Research Center, Department of Radiology and Biomedical Imaging, Yale University, School of Medicine, New Haven, CT, USA
| | - Douglas L Rothman
- Magnetic Resonance Research Center, Department of Radiology and Biomedical Imaging, Yale University, School of Medicine, New Haven, CT, USA
| | - Shuhui Cai
- Department of Electronic Science, Xiamen University, Xiamen, Fujian, China
| | - Robin A de Graaf
- Magnetic Resonance Research Center, Department of Radiology and Biomedical Imaging, Yale University, School of Medicine, New Haven, CT, USA.
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6
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Lindeboom L, de Graaf RA. Measurement of lipid composition in human skeletal muscle and adipose tissue with1H-MRS homonuclear spectral editing. Magn Reson Med 2017; 79:619-627. [DOI: 10.1002/mrm.26740] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 03/15/2017] [Accepted: 04/10/2017] [Indexed: 01/13/2023]
Affiliation(s)
- Lucas Lindeboom
- Department of Radiology; NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center; Maastricht the Netherlands
- Department of Human Biology/Human Movement Sciences; NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center; Maastricht the Netherlands
| | - Robin A. de Graaf
- Department of Radiology and Biomedical Imaging; Magnetic Resonance Research Center, Yale University School of Medicine; New Haven Connecticut USA
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7
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Cheshkov S, Dimitrov IE, Jakkamsetti V, Good L, Kelly D, Rajasekaran K, DeBerardinis RJ, Pascual JM, Sherry AD, Malloy CR. Oxidation of [U- 13 C]glucose in the human brain at 7T under steady state conditions. Magn Reson Med 2017; 78:2065-2071. [PMID: 28112825 DOI: 10.1002/mrm.26603] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 11/23/2016] [Accepted: 12/16/2016] [Indexed: 12/24/2022]
Abstract
PURPOSE Disorders of brain energy metabolism and neurotransmitter recycling have been implicated in multiple neurological conditions. 13 C magnetic resonance spectroscopy (13 C MRS) during intravenous administration of 13 C-labeled compounds has been used to measure turnover rates of brain metabolites. This approach, however, requires prolonged infusion inside the magnet. Proton decoupling is typically required but may be difficult to implement with standard equipment. We examined an alternative approach to monitor glucose metabolism in the human brain. METHODS 13 C-enriched glucose was infused in healthy subjects outside the magnet to a steady-state level of 13 C enrichment. Subsequently, the subjects were scanned at 7T for 60 min without 1 H decoupling. Metabolic modeling was used to calculate anaplerosis. RESULTS Biomarkers of energy metabolism and anaplerosis were detected. The glutamate C5 doublet provided information about glucose-derived acetyl-coenzyme A flux into the tricarboxylic acid (TCA) cycle via pyruvate dehydrogenase, and the bicarbonate signal reflected overall TCA cycle activity. The glutamate C1/C5 ratio is sensitive to anaplerosis. CONCLUSION Brain 13 C MRS at 7T provides information about glucose oxidation and anaplerosis without the need of prolonged 13 C infusions inside the scanner and without technical challenges of 1 H decoupling, making it a feasible approach for clinical research. Magn Reson Med 78:2065-2071, 2017. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Sergey Cheshkov
- 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
| | - Ivan E Dimitrov
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,Philips Medical Systems, Cleveland, Ohio, USA
| | - Vikram Jakkamsetti
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Levi Good
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Dorothy Kelly
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Karthik Rajasekaran
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Ralph J DeBerardinis
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Juan M Pascual
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,Department of Physiology, 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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8
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Hamilton G, Schlein AN, Middleton MS, Hooker CA, Wolfson T, Gamst AC, Loomba R, Sirlin CB. In vivo triglyceride composition of abdominal adipose tissue measured by 1 H MRS at 3T. J Magn Reson Imaging 2016; 45:1455-1463. [PMID: 27571403 DOI: 10.1002/jmri.25453] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 08/16/2016] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To investigate the regional variability of adipose tissue triglyceride composition in vivo using 1 H MRS, examining potential confounders and corrections for artifacts, to allow for adipose tissue spectrum estimation. MATERIALS AND METHODS 1 H magnetic resonance (MR) stimulated echo acquisition mode (STEAM) spectra were acquired in vivo at 3T from 340 adult patients (mean age 48.9 years, range 21-79 years; 172 males, 168 females; mean body mass index [BMI] 34.0, range 22-49 kg/m2 ) with known or suspected nonalcoholic fatty liver disease (NAFLD) in deep (dSCAT), surface (sSCAT) subcutaneous adipose tissue, and visceral adipose tissue (VAT). Triglyceride composition was characterized by the number of double bonds (ndb) and number of methylene-interrupted double bonds (nmidb). A subset of patients (dSCAT n = 80, sSCAT n = 55, VAT n = 194) had the acquisition repeated three times to examine the repeatability of ndb and nmidb estimation. RESULTS Mean ndb and nmidb showed significant (P < 0.0001) differences between depots except for dSCAT and sSCAT nmidb (dSCAT ndb 2.797, nmidb 0.745; sSCAT ndb 2.826, nmidb 0.737; VAT ndb 2.723, nmidb 0.687). All ndb and nmidb estimates were highly repeatable (VAT ndb ICC = 0.888, nmidb ICC = 0.853; sSCAT: ndb ICC = 0.974, nmidb ICC = 0.964; dSCAT: ndb ICC = 0.959, nmidb ICC = 0.948). CONCLUSION Adipose tissue composition can be estimated repeatably using 1 H MRS and different fat depots have different triglyceride compositions. LEVEL OF EVIDENCE 2 J. MAGN. RESON. IMAGING 2017;45:1455-1463.
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Affiliation(s)
- Gavin Hamilton
- Liver Imaging Group, Department of Radiology, University of California, San Diego, San Diego, California, USA
| | - Alexandra N Schlein
- Liver Imaging Group, Department of Radiology, University of California, San Diego, San Diego, California, USA
| | - Michael S Middleton
- Liver Imaging Group, Department of Radiology, University of California, San Diego, San Diego, California, USA
| | - Catherine A Hooker
- Liver Imaging Group, Department of Radiology, University of California, San Diego, San Diego, California, USA
| | - Tanya Wolfson
- Computational and Applied Statistics Lab, San Diego Supercomputing Center, San Diego, California, USA
| | - Anthony C Gamst
- Computational and Applied Statistics Lab, San Diego Supercomputing Center, San Diego, California, USA
| | - Rohit Loomba
- Department of Family Medicine and Public Health, University of California, San Diego, San Diego, California, USA.,NAFLD Translational Research Unit, Division of Gastroenterology, Department of Medicine, University of California, San Diego, San Diego, California, USA
| | - Claude B Sirlin
- Liver Imaging Group, Department of Radiology, University of California, San Diego, San Diego, California, USA
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9
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In vivo N-15 MRS study of glutamate metabolism in the rat brain. Anal Biochem 2016; 529:179-192. [PMID: 27580850 DOI: 10.1016/j.ab.2016.08.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 08/22/2016] [Accepted: 08/24/2016] [Indexed: 01/05/2023]
Abstract
In vivo 15N MRS has made a unique contribution to kinetic studies of the individual pathways that control glutamate flux in the rat brain. This review covers the following topics: (1) the advantages and limitations of in vivo 15N MRS and its indirect detection through coupled 1H; (2) kinetic methods; (3) major findings from our and other laboratories in the areas: (a) the uptake of the neurotransmitter glutamate from the extracellular fluid into glia; (b) the metabolism of glutamate to glutamine; (c) glutamine transport to the extracellular fluid; (d) hydrolysis of neuronal glutamine to glutamate; and (e) contribution of transamination from leucine to replenish the glutamate nitrogen. In vivo glutamine synthetase activities measured at several levels of hyperammonemia showed that this enzyme becomes saturated at blood ammonia concentration >0.9 μmol/g, and causes the elevation of brain ammonia. Implications of the results for the cause of hyperammonemic encephalopathy are discussed. Leucine provides >25% of glutamate nitrogen. An intriguing possibility that supplementing leucine may restore cognitive function after brain injury is discussed. Finally, some characteristics of 15N MRS that may facilitate the future application of this technique to the study of the human brain at 4 or 7 T are described.
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10
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Lindeboom L, de Graaf RA, Nabuurs CI, van Ewijk PA, Hesselink MK, Wildberger JE, Schrauwen P, Schrauwen-Hinderling VB. Quantum coherence spectroscopy to measure dietary fat retention in the liver. JCI Insight 2016; 1:e84671. [PMID: 27699229 DOI: 10.1172/jci.insight.84671] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The prevalence of fatty liver reaches alarming proportions. Fatty liver increases the risk for insulin resistance, cardiovascular disease, and nonalcoholic steatohepatitis (NASH). Although extensively studied in a preclinical setting, the lack of noninvasive methodologies hampers our understanding of which pathways promote hepatic fat accumulation in humans. Dietary fat retention is one of the pathways that may lead to fatty liver. The low (1.1%) natural abundance (NA) of carbon-13 (13C) allows use of 13C-enriched lipids for in vivo MR studies. Successful implementation of such methodology, however, is challenging due to low sensitivity of 13C-magnetic resonance spectroscopy (13C-MRS). Here, we investigated the use of 1-dimensional gradient enhanced heteronuclear single quantum coherence (ge-HSQC) spectroscopy for the in vivo detection of hepatic 1H-[13C]-lipid signals after a single high-fat meal with 13C-labeled fatty acids in 5 lean and 6 obese subjects. Postprandial retention of orally administered 13C-labeled fatty acids was significant (P < 0.01). Approximately 1.5% of the tracer was retained in the liver after 6 hours, and retention was similar in both groups (P = 0.92). Thus, a substantial part of the liver fat can originate directly from storage of meal-derived fat. The ge-HSQC can be used to noninvasively reveal the contribution of dietary fat to the development of hepatic steatosis over time.
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Affiliation(s)
- Lucas Lindeboom
- Departments of Radiology.,Human Biology and Human Movement Sciences, NUTRIM school for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, Netherlands.,Top Institute Food and Nutrition, Wageningen, Netherlands
| | - Robin A de Graaf
- Department of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Christine I Nabuurs
- Departments of Radiology.,Human Biology and Human Movement Sciences, NUTRIM school for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, Netherlands.,Top Institute Food and Nutrition, Wageningen, Netherlands
| | | | - Matthijs Kc Hesselink
- Human Biology and Human Movement Sciences, NUTRIM school for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, Netherlands
| | | | - Patrick Schrauwen
- Departments of Radiology.,Human Biology and Human Movement Sciences, NUTRIM school for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, Netherlands.,Top Institute Food and Nutrition, Wageningen, Netherlands
| | - Vera B Schrauwen-Hinderling
- Departments of Radiology.,Human Biology and Human Movement Sciences, NUTRIM school for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, Netherlands.,Top Institute Food and Nutrition, Wageningen, Netherlands
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11
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Li S, An L, Yu S, Araneta MF, Johnson CS, Wang S, Shen J. (13)C MRS of human brain at 7 Tesla using [2-(13)C]glucose infusion and low power broadband stochastic proton decoupling. Magn Reson Med 2016; 75:954-61. [PMID: 25917936 PMCID: PMC4624052 DOI: 10.1002/mrm.25721] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 03/12/2015] [Accepted: 03/12/2015] [Indexed: 11/05/2022]
Abstract
PURPOSE Carbon-13 ((13)C) MR spectroscopy (MRS) of the human brain at 7 Tesla (T) may pose patient safety issues due to high radiofrequency (RF) power deposition for proton decoupling. The purpose of present work is to study the feasibility of in vivo (13)C MRS of human brain at 7 T using broadband low RF power proton decoupling. METHODS Carboxylic/amide (13)C MRS of human brain by broadband stochastic proton decoupling was demonstrated on a 7 T scanner. RF safety was evaluated using the finite-difference time-domain method. (13)C signal enhancement by nuclear Overhauser effect (NOE) and proton decoupling was evaluated in both phantoms and in vivo. RESULTS At 7 T, the peak amplitude of carboxylic/amide (13)C signals was increased by a factor of greater than 4 due to the combined effects of NOE and proton decoupling. The 7 T (13)C MRS technique used decoupling power and average transmit power of less than 35 watts (W) and 3.6 W, respectively. CONCLUSION In vivo (13)C MRS studies of human brain can be performed at 7 T, well below the RF safety threshold, by detecting carboxylic/amide carbons with broadband stochastic proton decoupling.
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Affiliation(s)
- Shizhe Li
- Magnetic Resonance Spectroscopy Core Facility, National Institute
of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Li An
- Molecular Imaging Branch, National Institute of Mental Health,
National Institutes of Health, Bethesda, MD, USA
| | - Shao Yu
- Department of Electrical and Computer Engineering, Auburn
University, Auburn, AL, USA
| | - Maria Ferraris Araneta
- Molecular Imaging Branch, National Institute of Mental Health,
National Institutes of Health, Bethesda, MD, USA
| | - Christopher S. Johnson
- Molecular Imaging Branch, National Institute of Mental Health,
National Institutes of Health, Bethesda, MD, USA
| | - Shumin Wang
- Department of Electrical and Computer Engineering, Auburn
University, Auburn, AL, USA
| | - Jun Shen
- Magnetic Resonance Spectroscopy Core Facility, National Institute
of Mental Health, National Institutes of Health, Bethesda, MD, USA
- Molecular Imaging Branch, National Institute of Mental Health,
National Institutes of Health, Bethesda, MD, USA
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