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Nantogma S, Chowdhury MRH, Kabir MSH, Adelabu I, Joshi SM, Samoilenko A, de Maissin H, Schmidt AB, Nikolaou P, Chekmenev YA, Salnikov OG, Chukanov NV, Koptyug IV, Goodson BM, Chekmenev EY. MATRESHCA: Microtesla Apparatus for Transfer of Resonance Enhancement of Spin Hyperpolarization via Chemical Exchange and Addition. Anal Chem 2024; 96:4171-4179. [PMID: 38358916 PMCID: PMC10939749 DOI: 10.1021/acs.analchem.3c05233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
We present an integrated, open-source device for parahydrogen-based hyperpolarization processes in the microtesla field regime with a cost of components of less than $7000. The device is designed to produce a batch of 13C and 15N hyperpolarized (HP) compounds via hydrogenative or non-hydrogenative parahydrogen-induced polarization methods that employ microtesla magnetic fields for efficient polarization transfer of parahydrogen-derived spin order to X-nuclei (e.g., 13C and 15N). The apparatus employs a layered structure (reminiscent of a Russian doll "Matryoshka") that includes a nonmagnetic variable-temperature sample chamber, a microtesla magnetic field coil (operating in the range of 0.02-75 microtesla), a three-layered mu-metal shield (to attenuate the ambient magnetic field), and a magnetic shield degaussing coil placed in the overall device enclosure. The gas-handling manifold allows for parahydrogen-gas flow and pressure control (up to 9.2 bar of total parahydrogen pressure). The sample temperature can be varied either using a water bath or a PID-controlled heat exchanger in the range from -12 to 80 °C. This benchtop device measures 62 cm (length) × 47 cm (width) × 47 cm (height), weighs 30 kg, and requires only connections to a high-pressure parahydrogen gas supply and a single 110/220 VAC power source. The utility of the device has been demonstrated using an example of parahydrogen pairwise addition to form HP ethyl [1-13C]acetate (P13C = 7%, [c] = 1 M). Moreover, the Signal Amplification By Reversible Exchange in SHield Enables Alignment Transfer to Heteronuclei (SABRE-SHEATH) technique was employed to demonstrate efficient hyperpolarization of 13C and 15N spins in a wide range of biologically relevant molecules, including [1-13C]pyruvate (P13C = 14%, [c] = 27 mM), [1-13C]-α-ketoglutarate (P13C = 17%), [1-13C]ketoisocaproate (P13C = 18%), [15N3]metronidazole (P15N = 13%, [c] = 20 mM), and others. While the vast majority of the utility studies have been performed in standard 5 mm NMR tubes, the sample chamber of the device can accommodate a wide range of sample container sizes and geometries of up to 1 L sample volume. The device establishes an integrated, simple, inexpensive, and versatile equipment gateway needed to facilitate parahydrogen-based hyperpolarization experiments ranging from basic science to preclinical applications; indeed, detailed technical drawings and a bill of materials are provided to support the ready translation of this design to other laboratories.
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Affiliation(s)
- Shiraz Nantogma
- Department of Chemistry, Integrative Biosciences (Ibio), Wayne State University, Karmanos Cancer Institute (KCI), Detroit, Michigan 48202, United States
| | - Md Raduanul H. Chowdhury
- Department of Chemistry, Integrative Biosciences (Ibio), Wayne State University, Karmanos Cancer Institute (KCI), Detroit, Michigan 48202, United States
| | - Mohammad S. H. Kabir
- Department of Chemistry, Integrative Biosciences (Ibio), Wayne State University, Karmanos Cancer Institute (KCI), Detroit, Michigan 48202, United States
| | - Isaiah Adelabu
- Department of Chemistry, Integrative Biosciences (Ibio), Wayne State University, Karmanos Cancer Institute (KCI), Detroit, Michigan 48202, United States
| | - Sameer M. Joshi
- Department of Chemistry, Integrative Biosciences (Ibio), Wayne State University, Karmanos Cancer Institute (KCI), Detroit, Michigan 48202, United States
| | - Anna Samoilenko
- Department of Chemistry, Integrative Biosciences (Ibio), Wayne State University, Karmanos Cancer Institute (KCI), Detroit, Michigan 48202, United States
| | - Henri de Maissin
- German Cancer Consortium (DKTK), Partner Site Freiburg, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
- Division of Medical Physics, Department of Radiology, Medical Center, University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg 79106, Germany
| | - Andreas B. Schmidt
- Department of Chemistry, Integrative Biosciences (Ibio), Wayne State University, Karmanos Cancer Institute (KCI), Detroit, Michigan 48202, United States
- German Cancer Consortium (DKTK), Partner Site Freiburg, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
- Division of Medical Physics, Department of Radiology, Medical Center, University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg 79106, Germany
| | | | | | - Oleg G. Salnikov
- International Tomography Center SB RAS, Institutskaya Street 3A, Novosibirsk 630090, Russia
| | - Nikita V. Chukanov
- International Tomography Center SB RAS, Institutskaya Street 3A, Novosibirsk 630090, Russia
| | - Igor V. Koptyug
- International Tomography Center SB RAS, Institutskaya Street 3A, Novosibirsk 630090, Russia
| | - Boyd M. Goodson
- Department of Chemistry and Biochemistry, Materials Technology Center, Southern Illinois University, Carbondale, Illinois 62901, United States
| | - Eduard Y. Chekmenev
- Department of Chemistry, Integrative Biosciences (Ibio), Wayne State University, Karmanos Cancer Institute (KCI), Detroit, Michigan 48202, United States
- Russian Academy of Sciences, Leninskiy Prospekt 14, Moscow 119991, Russia
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2
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Schmidt AB, Adelabu I, Nelson C, Nantogma S, Kiselev VG, Zaitsev M, Abdurraheem A, de Maissin H, Rosen MS, Lehmkuhl S, Appelt S, Theis T, Chekmenev EY. 13C Radiofrequency Amplification by Stimulated Emission of Radiation Threshold Sensing of Chemical Reactions. J Am Chem Soc 2023; 145:11121-11129. [PMID: 37172079 PMCID: PMC10257364 DOI: 10.1021/jacs.3c00776] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Conventional nuclear magnetic resonance (NMR) enables detection of chemicals and their transformations by exciting nuclear spin ensembles with a radio-frequency pulse followed by detection of the precessing spins at their characteristic frequencies. The detected frequencies report on chemical reactions in real time and the signal amplitudes scale with concentrations of products and reactants. Here, we employ Radiofrequency Amplification by Stimulated Emission of Radiation (RASER), a quantum phenomenon producing coherent emission of 13C signals, to detect chemical transformations. The 13C signals are emitted by the negatively hyperpolarized biomolecules without external radio frequency pulses and without any background signal from other, nonhyperpolarized spins in the ensemble. Here, we studied the hydrolysis of hyperpolarized ethyl-[1-13C]acetate to hyperpolarized [1-13C]acetate, which was analyzed as a model system by conventional NMR and 13C RASER. The chemical transformation of 13C RASER-active species leads to complete and abrupt disappearance of reactant signals and delayed, abrupt reappearance of a frequency-shifted RASER signal without destroying 13C polarization. The experimentally observed "quantum" RASER threshold is supported by simulations.
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Affiliation(s)
- Andreas B. Schmidt
- Department of Chemistry, Integrative Bio-sciences (Ibio), Karmanos Cancer Institute (KCI), Wayne State University, Detroit, Michigan 48202, United States
- Division of Medical Physics, Department of Radiology, Medical Center, University of Freiburg, Faculty of Medicine, University of Freiburg, Killianstr. 5a, Freiburg 79106, Germany
- German Cancer Consortium (DKTK), partner site Freiburg and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg 69120, Germany
| | - Isaiah Adelabu
- Department of Chemistry, Integrative Bio-sciences (Ibio), Karmanos Cancer Institute (KCI), Wayne State University, Detroit, Michigan 48202, United States
| | - Christopher Nelson
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Shiraz Nantogma
- Department of Chemistry, Integrative Bio-sciences (Ibio), Karmanos Cancer Institute (KCI), Wayne State University, Detroit, Michigan 48202, United States
| | - Valerij G. Kiselev
- Division of Medical Physics, Department of Radiology, Medical Center, University of Freiburg, Faculty of Medicine, University of Freiburg, Killianstr. 5a, Freiburg 79106, Germany
| | - Maxim Zaitsev
- Division of Medical Physics, Department of Radiology, Medical Center, University of Freiburg, Faculty of Medicine, University of Freiburg, Killianstr. 5a, Freiburg 79106, Germany
| | - Abubakar Abdurraheem
- Department of Chemistry, Integrative Bio-sciences (Ibio), Karmanos Cancer Institute (KCI), Wayne State University, Detroit, Michigan 48202, United States
| | - Henri de Maissin
- Division of Medical Physics, Department of Radiology, Medical Center, University of Freiburg, Faculty of Medicine, University of Freiburg, Killianstr. 5a, Freiburg 79106, Germany
- German Cancer Consortium (DKTK), partner site Freiburg and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg 69120, Germany
| | - Matthew S. Rosen
- Massachusetts General Hospital, A. A. Martinos Center for Biomedical Imaging, Boston, MA 02129, United States
- Department of Physics, Harvard University; Cambridge, MA 02138, United States
| | - Sören Lehmkuhl
- Institute of Microstructure Technology, Karlsruhe Institute of Technology; 76344 Eggenstein-Leopoldshafen, Karlsruhe, Germany
| | - Stephan Appelt
- Institute of Technical and Macromolecular Chemistry, RWTH Aachen University; 52056 Aachen, Germany
- Central Institute for Engineering, Electronics and Analytics – Electronic Systems (ZEA-2), Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany
| | - Thomas Theis
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
- Department of Physics, North Carolina State University, Raleigh, North Carolina 27606, United States
- Joint UNC & NC State Department of Biomedical Engineering, North Carolina State University, Raleigh, North Carolina 27606, United States
| | - Eduard Y. Chekmenev
- Department of Chemistry, Integrative Bio-sciences (Ibio), Karmanos Cancer Institute (KCI), Wayne State University, Detroit, Michigan 48202, United States
- Russian Academy of Sciences, 119991 Moscow, Russia
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Stulczewski D, Zgorzynska E, Dziedzic B, Wieczorek-Szukala K, Szafraniec K, Walczewska A. EPA stronger than DHA increases the mitochondrial membrane potential and cardiolipin levels but does not change the ATP level in astrocytes. Exp Cell Res 2023; 424:113491. [PMID: 36708860 DOI: 10.1016/j.yexcr.2023.113491] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 12/22/2022] [Accepted: 01/22/2023] [Indexed: 01/27/2023]
Abstract
Astrocytes are highly energy-consuming glial cells critical for metabolic support to neurons. A growing body of evidence suggests that mitochondrial dysfunction in astrocytes is involved in age-related neurodegenerative disorders and that fish oil, rich in docosahexaenoic (DHA) and eicosapentaenoic (EPA) fatty acids, may alleviate cognition impairment in Parkinson's and Alzheimer's diseases. The present study examines the effect of DHA and EPA on mitochondrial membrane potential (MMP), apoptosis activation and ATP levels in astrocytes cultured in medium containing glucose or galactose, which limits oxidative phosphorylation (OXPHOS). MMP, expressed as the ratio of red to green JC-10 and MitoTracker fluorescence, increased in EPA-incubated cells in a dose dependent manner and was higher than in DHA-incubated astrocytes, also after uncoupling of OXPHOS by carbonyl cyanide 3-chlorophenylhydrazone (CCCP). In cells cultured in glucose and galactose medium mitochondrial hyperpolarization had no impact on intracellular ATP level. Furthermore, both EPA and DHA elevated mitochondrial cardiolipin content, however only EPA did so in a dose-dependent manner and reduced apoptosis which was analyzed by flow cytometry.
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Affiliation(s)
- Dawid Stulczewski
- Department of Cell-to-Cell Communication, Medical University of Lodz, Mazowiecka 6/8, 92-215, Lodz, Poland
| | - Emilia Zgorzynska
- Department of Cell-to-Cell Communication, Medical University of Lodz, Mazowiecka 6/8, 92-215, Lodz, Poland.
| | - Barbara Dziedzic
- Department of Cell-to-Cell Communication, Medical University of Lodz, Mazowiecka 6/8, 92-215, Lodz, Poland
| | | | - Kacper Szafraniec
- Department of Cell-to-Cell Communication, Medical University of Lodz, Mazowiecka 6/8, 92-215, Lodz, Poland
| | - Anna Walczewska
- Department of Cell-to-Cell Communication, Medical University of Lodz, Mazowiecka 6/8, 92-215, Lodz, Poland
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Divergent Cellular Energetics, Glutamate Metabolism, and Mitochondrial Function Between Human and Mouse Cerebral Cortex. Mol Neurobiol 2022; 59:7495-7512. [PMID: 36201140 DOI: 10.1007/s12035-022-03053-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 09/24/2022] [Indexed: 10/10/2022]
Abstract
Disruptions of brain energy and neurotransmitter metabolism are associated with several pathological conditions including neurodegenerative diseases such as Alzheimer's disease. Transgenic rodent models, and in vitro preparations hereof, are often applied for studying pathological aspects of brain metabolism. However, despite the conserved cerebral development across mammalian species, distinct differences in cellular composition and structure may influence metabolism of the rodent and human brain. To address this, we investigated the metabolic function of acutely isolated brain slices and non-synaptic mitochondria obtained from the cerebral cortex of mice and neurosurgically resected neocortical tissue of humans. Utilizing dynamic isotope labeling with 13C-enriched metabolic substrates, we show that metabolism of glucose, acetate, β-hydroxybutyrate, and glutamine operates at lower rates in human cerebral cortical slices when compared to mouse slices. In contrast, human cerebral cortical slices display a higher capacity for converting exogenous glutamate into glutamine, which subsequently supports neuronal GABA synthesis, whereas mouse slices primarily convert glutamate into aspartate. In line with the reduced metabolic rate of the human brain slices, isolated non-synaptic mitochondria of the human cerebral cortex have a lower oxygen consumption rate when provided succinate as substrate. However, when provided pyruvate and malate, human mitochondria display a higher coupled respiration and lower proton leak, signifying a more efficient mitochondrial coupling compared to mouse mitochondria. This study reveals key differences between mouse and human brain metabolism concerning both neurons and astrocytes, which must be taken into account when applying in vitro rodent preparations as a model system of the human brain.
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Adelabu I, Ettedgui J, Joshi SM, Nantogma S, Chowdhury MRH, McBride S, Theis T, Sabbasani VR, Chandrasekhar M, Sail D, Yamamoto K, Swenson RE, Krishna MC, Goodson BM, Chekmenev EY. Rapid 13C Hyperpolarization of the TCA Cycle Intermediate α-Ketoglutarate via SABRE-SHEATH. Anal Chem 2022; 94:13422-13431. [PMID: 36136056 PMCID: PMC9907724 DOI: 10.1021/acs.analchem.2c02160] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
α-Ketoglutarate is a key biomolecule involved in a number of metabolic pathways─most notably the TCA cycle. Abnormal α-ketoglutarate metabolism has also been linked with cancer. Here, isotopic labeling was employed to synthesize [1-13C,5-12C,D4]α-ketoglutarate with the future goal of utilizing its [1-13C]-hyperpolarized state for real-time metabolic imaging of α-ketoglutarate analytes and its downstream metabolites in vivo. The signal amplification by reversible exchange in shield enables alignment transfer to heteronuclei (SABRE-SHEATH) hyperpolarization technique was used to create 9.7% [1-13C] polarization in 1 minute in this isotopologue. The efficient 13C hyperpolarization, which utilizes parahydrogen as the source of nuclear spin order, is also supported by favorable relaxation dynamics at 0.4 μT field (the optimal polarization transfer field): the exponential 13C polarization buildup constant Tb is 11.0 ± 0.4 s whereas the 13C polarization decay constant T1 is 18.5 ± 0.7 s. An even higher 13C polarization value of 17.3% was achieved using natural-abundance α-ketoglutarate disodium salt, with overall similar relaxation dynamics at 0.4 μT field, indicating that substrate deuteration leads only to a slight increase (∼1.2-fold) in the relaxation rates for 13C nuclei separated by three chemical bonds. Instead, the gain in polarization (natural abundance versus [1-13C]-labeled) is rationalized through the smaller heat capacity of the "spin bath" comprising available 13C spins that must be hyperpolarized by the same number of parahydrogen present in each sample, in line with previous 15N SABRE-SHEATH studies. Remarkably, the C-2 carbon was not hyperpolarized in both α-ketoglutarate isotopologues studied; this observation is in sharp contrast with previously reported SABRE-SHEATH pyruvate studies, indicating that the catalyst-binding dynamics of C-2 in α-ketoglutarate differ from that in pyruvate. We also demonstrate that 13C spectroscopic characterization of α-ketoglutarate and pyruvate analytes can be performed at natural 13C abundance with an estimated detection limit of 80 micromolar concentration × *%P13C. All in all, the fundamental studies reported here enable a wide range of research communities with a new hyperpolarized contrast agent potentially useful for metabolic imaging of brain function, cancer, and other metabolically challenging diseases.
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Affiliation(s)
- Isaiah Adelabu
- Department of Chemistry, Integrative Biosciences (Ibio), Wayne State University, Karmanos Cancer Institute (KCI), Detroit, Michigan 48202, United States
| | - Jessica Ettedgui
- Chemistry and Synthesis Center, National Heart, Lung, and Blood Institute 9800 Medical Center Drive, Building B, Room #2034, Bethesda, Maryland 20850, United States
| | - Sameer M. Joshi
- Department of Chemistry, Integrative Biosciences (Ibio), Wayne State University, Karmanos Cancer Institute (KCI), Detroit, Michigan 48202, United States
| | - Shiraz Nantogma
- Department of Chemistry, Integrative Biosciences (Ibio), Wayne State University, Karmanos Cancer Institute (KCI), Detroit, Michigan 48202, United States
| | - Md Raduanul H. Chowdhury
- Department of Chemistry, Integrative Biosciences (Ibio), Wayne State University, Karmanos Cancer Institute (KCI), Detroit, Michigan 48202, United States
| | - Stephen McBride
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina, 27695-8204, United States
| | - Thomas Theis
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina, 27695-8204, United States
| | - Venkata R. Sabbasani
- Chemistry and Synthesis Center, National Heart, Lung, and Blood Institute 9800 Medical Center Drive, Building B, Room #2034, Bethesda, Maryland 20850, United States
| | - Mushti Chandrasekhar
- Chemistry and Synthesis Center, National Heart, Lung, and Blood Institute 9800 Medical Center Drive, Building B, Room #2034, Bethesda, Maryland 20850, United States
| | - Deepak Sail
- Chemistry and Synthesis Center, National Heart, Lung, and Blood Institute 9800 Medical Center Drive, Building B, Room #2034, Bethesda, Maryland 20850, United States
| | - Kazutoshi Yamamoto
- Radiation Biology Branch, Center for Cancer Research, NCI, NIH, Bethesda, Maryland 20892, United States
| | - Rolf E. Swenson
- Chemistry and Synthesis Center, National Heart, Lung, and Blood Institute 9800 Medical Center Drive, Building B, Room #2034, Bethesda, Maryland 20850, United States
| | - Murali C. Krishna
- Center for Cancer Research, National Cancer Institute, Bethesda, 31 Center Drive Maryland 20814, United States
| | - Boyd M. Goodson
- School of Chemical & Biomolecular Sciences and Materials Technology Center, Southern Illinois University, Carbondale, Illinois 62901, United States
| | - Eduard Y. Chekmenev
- Department of Chemistry, Integrative Biosciences (Ibio), Wayne State University, Karmanos Cancer Institute (KCI), Detroit, Michigan 48202, United States
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Repetitive Transcranial Magnetic Stimulation-Associated Changes in Neocortical Metabolites in Major Depression: A Systematic Review. Neuroimage Clin 2022; 35:103049. [PMID: 35738081 PMCID: PMC9233277 DOI: 10.1016/j.nicl.2022.103049] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 04/01/2022] [Accepted: 05/12/2022] [Indexed: 11/23/2022]
Abstract
We reviewed 12 studies that measured metabolites pre and post rTMS in MDD. Frontal lobe Glu, Gln, NAA, and GABA increased after rTMS. Increases in metabolites were often associated with MDD symptom improvement. We propose novel intracellular mechanisms by which metabolites are altered by rTMS.
Introduction Repetitive Transcranial magnetic stimulation (rTMS) is an FDA approved treatment for major depressive disorder (MDD). However, neural mechanisms contributing to rTMS effects on depressive symptoms, cognition, and behavior are unclear. Proton magnetic resonance spectroscopy (MRS), a noninvasive neuroimaging technique measuring concentrations of biochemical compounds within the brain in vivo, may provide mechanistic insights. Methods This systematic review summarized published MRS findings from rTMS treatment trials to address potential neurometabolic mechanisms of its antidepressant action. Using PubMed, Google Scholar, Web of Science, and JSTOR, we identified twelve empirical studies that evaluated changes in MRS metabolites in a within-subjects, pre- vs. post-rTMS treatment design in patients with MDD. Results rTMS protocols ranged from four days to eight weeks duration, were applied at high frequency to the left dorsolateral prefrontal cortex (DLPFC) in most studies, and were conducted in patients aged 13-to-70. Most studies utilized MRS point resolved spectroscopy acquisitions at 3 Tesla in the bilateral anterior cingulate cortex and DLPFC. Symptom improvements were correlated with rTMS-related increases in the concentration of glutamatergic compounds (glutamate, Glu, and glutamine, Gln), GABA, and N-acetylated compounds (NAA), with some results trend-level. Conclusions This is the first in-depth systematic review of metabolic effects of rTMS in individuals with MDD. The extant literature suggests rTMS stimulation does not produce changes in neurometabolites independent of clinical response; increases in frontal lobe glutamatergic compounds, N-acetylated compounds and GABA following high frequency left DLPFC rTMS therapy were generally associated with clinical improvement. Glu, Gln, GABA, and NAA may mediate rTMS treatment effects on MDD symptomatology through intracellular mechanisms.
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Abstract
The energy cost of information processing is thought to be chiefly neuronal, with a minor fraction attributed to glial cells. However, there is compelling evidence that astrocytes capture synaptic K+ using their Na+/K+ ATPase, and not solely through Kir4.1 channels as was once thought. When this active buffering is taken into account, the cost of astrocytes rises by >200%. Gram-per-gram, astrocytes turn out to be as expensive as neurons. This conclusion is supported by 3D reconstruction of the neuropil showing similar mitochondrial densities in neurons and astrocytes, by cell-specific transcriptomics and proteomics, and by the rates of the tricarboxylic acid cycle. Possible consequences for reactive astrogliosis and brain disease are discussed.
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Affiliation(s)
- L F Barros
- Centro de Estudios Científicos - CECs, Valdivia, Chile
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Mandal PK, Guha Roy R, Samkaria A, Maroon JC, Arora Y. In Vivo 13C Magnetic Resonance Spectroscopy for Assessing Brain Biochemistry in Health and Disease. Neurochem Res 2022; 47:1183-1201. [PMID: 35089504 DOI: 10.1007/s11064-022-03538-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 01/15/2022] [Accepted: 01/19/2022] [Indexed: 12/27/2022]
Abstract
Magnetic resonance spectroscopy (MRS) is a non-invasive technique that contributes to the elucidation of brain biochemistry. 13C MRS enables the detection of specific neurochemicals and their neuroenergetic correlation with neuronal function. The synergistic outcome of 13C MRS and the infusion of 13C-labeled substrates provide an understanding of neurometabolism and the role of glutamate/gamma-aminobutyric acid (GABA) neurotransmission in diseases, such as Alzheimer's disease, schizophrenia, and bipolar disorder. Moreover, 13C MRS provides a window into the altered flux rate of different pathways, including the tricarboxylic acid cycle (TCA) and the glutamate/glutamine/GABA cycle, in health and in various diseases. Notably, the metabolic flux rate of the TCA cycle often decreases in neurodegenerative diseases. Additionally, 13C MRS can be used to investigate several psychiatric and neurological disorders as it directly reflects the real-time production and alterations of key brain metabolites. This review aims to highlight the chronology, the technological advancements, and the applications of 13C MRS in various brain diseases.
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Affiliation(s)
- Pravat K Mandal
- Neuroimaging and Neurospectroscopy (NINS) Laboratory, National Brain Research Centre (NBRC), Gurgaon, India.
- Florey Institute of Neuroscience and Mental Health, Melbourne School of Medicine Campus, Melbourne, Australia.
| | - Rimil Guha Roy
- Neuroimaging and Neurospectroscopy (NINS) Laboratory, National Brain Research Centre (NBRC), Gurgaon, India
| | - Avantika Samkaria
- Neuroimaging and Neurospectroscopy (NINS) Laboratory, National Brain Research Centre (NBRC), Gurgaon, India
| | - Joseph C Maroon
- Department of Neurosurgery, University of Pittsburgh Medical School, Pittsburgh, PA, USA
| | - Yashika Arora
- Neuroimaging and Neurospectroscopy (NINS) Laboratory, National Brain Research Centre (NBRC), Gurgaon, India
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Gao R, Ren L, Zhou Y, Wang L, Xie Y, Zhang M, Liu X, Ke S, Wu K, Zheng J, Liu X, Chen Z, Liu L. Recurrent non-severe hypoglycemia aggravates cognitive decline in diabetes and induces mitochondrial dysfunction in cultured astrocytes. Mol Cell Endocrinol 2021; 526:111192. [PMID: 33545179 DOI: 10.1016/j.mce.2021.111192] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 01/26/2021] [Accepted: 01/29/2021] [Indexed: 12/13/2022]
Abstract
The present study aimed to determine the relationship between astrocytes and recurrent non-severe hypoglycemia (RH)2 -associated cognitive decline in diabetes. RH induced cognitive impairment and neuronal cell death in the cerebral cortex of diabetic mice, accompanied by excessive activation of astrocytes. Levels of the neurotrophins BDNF and GDNF, together with BDNF and GDNF- related signaling, were downregulated by RH. In vitro, recurrent low glucose (RLG)3 impaired cell viability and induced apoptosis of high-glucose cultured astrocytes. Accumulating mitochondrial ROS and dysregulated mitochondrial functions, including abnormal morphology, decreased membrane potential, downregulated ATP levels, and disrupted bioenergetic status, were observed in these cells. SS-31 mediated protection of mitochondrial functions reversed RLG-induced cell viability defects and neurotrophin production. These findings demonstrate that RH induced astrocyte overactivation and mitochondrial dysfunction, leading to astrocyte-derived neurotrophin disturbance, which might contribute to diabetic cognitive decline. Targeting astrocyte mitochondria might represent a neuroprotective therapy for hypoglycemia-associated neurodegeneration in diabetes.
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Affiliation(s)
- Ruonan Gao
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, 350001, China
| | - Lingjia Ren
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, 350001, China
| | - Yu Zhou
- Department of Clinical Pharmacy and Pharmacy Administration, School of Pharmacy, Fujian Medical University, Fuzhou, 350122, China
| | - Lijing Wang
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, 350001, China
| | - Yunzhen Xie
- Department of Clinical Pharmacy and Pharmacy Administration, School of Pharmacy, Fujian Medical University, Fuzhou, 350122, China
| | - Mengjun Zhang
- Department of pharmacy, Zhongshan Hopital, Fudan University (Xiamen Branch), Xiamen, 361000, China
| | - Xiaoying Liu
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, 350001, China
| | - Sujie Ke
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, 350001, China
| | - Kejun Wu
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, 350001, China
| | - Jiaping Zheng
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, 350001, China
| | - Xiaohong Liu
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, 350001, China
| | - Zhou Chen
- Department of Clinical Pharmacy and Pharmacy Administration, School of Pharmacy, Fujian Medical University, Fuzhou, 350122, China.
| | - Libin Liu
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, 350001, China.
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10
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Svyatova A, Kozinenko VP, Chukanov NV, Burueva DB, Chekmenev EY, Chen YW, Hwang DW, Kovtunov KV, Koptyug IV. PHIP hyperpolarized [1- 13C]pyruvate and [1- 13C]acetate esters via PH-INEPT polarization transfer monitored by 13C NMR and MRI. Sci Rep 2021; 11:5646. [PMID: 33707497 PMCID: PMC7952547 DOI: 10.1038/s41598-021-85136-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Accepted: 02/18/2021] [Indexed: 01/31/2023] Open
Abstract
Parahydrogen-induced polarization of 13C nuclei by side-arm hydrogenation (PHIP-SAH) for [1-13C]acetate and [1-13C]pyruvate esters with application of PH-INEPT-type pulse sequences for 1H to 13C polarization transfer is reported, and its efficiency is compared with that of polarization transfer based on magnetic field cycling (MFC). The pulse-sequence transfer approach may have its merits in some applications because the entire hyperpolarization procedure is implemented directly in an NMR or MRI instrument, whereas MFC requires a controlled field variation at low magnetic fields. Optimization of the PH-INEPT-type transfer sequences resulted in 13C polarization values of 0.66 ± 0.04% and 0.19 ± 0.02% for allyl [1-13C]pyruvate and ethyl [1-13C]acetate, respectively, which is lower than the corresponding polarization levels obtained with MFC for 1H to 13C polarization transfer (3.95 ± 0.05% and 0.65 ± 0.05% for allyl [1-13C]pyruvate and ethyl [1-13C]acetate, respectively). Nevertheless, a significant 13C NMR signal enhancement with respect to thermal polarization allowed us to perform 13C MR imaging of both biologically relevant hyperpolarized molecules which can be used to produce useful contrast agents for the in vivo imaging applications.
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Affiliation(s)
- Alexandra Svyatova
- grid.419389.e0000 0001 2163 7228International Tomography Center SB RAS, 3A Institutskaya St., Novosibirsk, Russia 630090 ,grid.4605.70000000121896553Novosibirsk State University, 2 Pirogova St., Novosibirsk, Russia 630090 ,grid.418953.2Institute of Cytology and Genetics SB RAS, 10 Ac. Lavrentieva Ave., Novosibirsk, Russia 630090
| | - Vitaly P. Kozinenko
- grid.419389.e0000 0001 2163 7228International Tomography Center SB RAS, 3A Institutskaya St., Novosibirsk, Russia 630090 ,grid.4605.70000000121896553Novosibirsk State University, 2 Pirogova St., Novosibirsk, Russia 630090
| | - Nikita V. Chukanov
- grid.419389.e0000 0001 2163 7228International Tomography Center SB RAS, 3A Institutskaya St., Novosibirsk, Russia 630090 ,grid.4605.70000000121896553Novosibirsk State University, 2 Pirogova St., Novosibirsk, Russia 630090
| | - Dudari B. Burueva
- grid.419389.e0000 0001 2163 7228International Tomography Center SB RAS, 3A Institutskaya St., Novosibirsk, Russia 630090 ,grid.4605.70000000121896553Novosibirsk State University, 2 Pirogova St., Novosibirsk, Russia 630090
| | - Eduard Y. Chekmenev
- grid.254444.70000 0001 1456 7807Department of Chemistry, Wayne State University, Detroit, MI 48201 USA ,grid.254444.70000 0001 1456 7807Karmanos Cancer Institute, Wayne State University, Detroit, MI 48201 USA ,grid.254444.70000 0001 1456 7807Integrative Biosciences, Wayne State University, Detroit, MI 48201 USA ,grid.4886.20000 0001 2192 9124Russian Academy of Sciences, Moscow, Russia 119991
| | - Yu-Wen Chen
- grid.28665.3f0000 0001 2287 1366Institute of Biomedical Sciences, Academia Sinica, Taipei, 115 Taiwan (Republic of China)
| | - Dennis W. Hwang
- grid.28665.3f0000 0001 2287 1366Institute of Biomedical Sciences, Academia Sinica, Taipei, 115 Taiwan (Republic of China)
| | - Kirill V. Kovtunov
- grid.419389.e0000 0001 2163 7228International Tomography Center SB RAS, 3A Institutskaya St., Novosibirsk, Russia 630090 ,grid.4605.70000000121896553Novosibirsk State University, 2 Pirogova St., Novosibirsk, Russia 630090
| | - Igor V. Koptyug
- grid.419389.e0000 0001 2163 7228International Tomography Center SB RAS, 3A Institutskaya St., Novosibirsk, Russia 630090
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11
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Nguyen H, Zerimech S, Baltan S. Astrocyte Mitochondria in White-Matter Injury. Neurochem Res 2021; 46:2696-2714. [PMID: 33527218 DOI: 10.1007/s11064-021-03239-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/05/2021] [Accepted: 01/06/2021] [Indexed: 12/11/2022]
Abstract
This review summarizes the diverse structure and function of astrocytes to describe the bioenergetic versatility required of astrocytes that are situated at different locations. The intercellular domain of astrocyte mitochondria defines their roles in supporting and regulating astrocyte-neuron coupling and survival against ischemia. The heterogeneity of astrocyte mitochondria, and how subpopulations of astrocyte mitochondria adapt to interact with other glia and regulate axon function, require further investigation. It has become clear that mitochondrial permeability transition pores play a key role in a wide variety of human diseases, whose common pathology may be based on mitochondrial dysfunction triggered by Ca2+ and potentiated by oxidative stress. Reactive oxygen species cause axonal degeneration and a reduction in axonal transport, leading to axonal dystrophies and neurodegeneration including Alzheimer's disease, amyotrophic lateral sclerosis, Parkinson's disease, and Huntington's disease. Developing new tools to allow better investigation of mitochondrial structure and function in astrocytes, and techniques to specifically target astrocyte mitochondria, can help to unravel the role of mitochondrial health and dysfunction in a more inclusive context outside of neuronal cells. Overall, this review will assess the value of astrocyte mitochondria as a therapeutic target to mitigate acute and chronic injury in the CNS.
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Affiliation(s)
- Hung Nguyen
- Anesthesiology and Peri-Operative Medicine (APOM), Oregon Health and Science University, Portland, OR, 97239, USA
| | - Sarah Zerimech
- Anesthesiology and Peri-Operative Medicine (APOM), Oregon Health and Science University, Portland, OR, 97239, USA
| | - Selva Baltan
- Anesthesiology and Peri-Operative Medicine (APOM), Oregon Health and Science University, Portland, OR, 97239, USA.
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12
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Ali MY, Oliva CR, Noman ASM, Allen BG, Goswami PC, Zakharia Y, Monga V, Spitz DR, Buatti JM, Griguer CE. Radioresistance in Glioblastoma and the Development of Radiosensitizers. Cancers (Basel) 2020; 12:E2511. [PMID: 32899427 PMCID: PMC7564557 DOI: 10.3390/cancers12092511] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 08/24/2020] [Accepted: 08/28/2020] [Indexed: 02/07/2023] Open
Abstract
Ionizing radiation is a common and effective therapeutic option for the treatment of glioblastoma (GBM). Unfortunately, some GBMs are relatively radioresistant and patients have worse outcomes after radiation treatment. The mechanisms underlying intrinsic radioresistance in GBM has been rigorously investigated over the past several years, but the complex interaction of the cellular molecules and signaling pathways involved in radioresistance remains incompletely defined. A clinically effective radiosensitizer that overcomes radioresistance has yet to be identified. In this review, we discuss the current status of radiation treatment in GBM, including advances in imaging techniques that have facilitated more accurate diagnosis, and the identified mechanisms of GBM radioresistance. In addition, we provide a summary of the candidate GBM radiosensitizers being investigated, including an update of subjects enrolled in clinical trials. Overall, this review highlights the importance of understanding the mechanisms of GBM radioresistance to facilitate the development of effective radiosensitizers.
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Affiliation(s)
- Md Yousuf Ali
- Interdisciplinary Graduate Program in Human Toxicology, University of Iowa, Iowa City, IA 52242, USA;
- Free Radical & Radiation Biology Program, Department of Radiation Oncology, Holden Comprehensive Cancer Center, University of Iowa, Iowa City, IA 52242, USA; (C.R.O.); (B.G.A.); (P.C.G.); (D.R.S.)
- Department of Radiation Oncology, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, USA;
| | - Claudia R. Oliva
- Free Radical & Radiation Biology Program, Department of Radiation Oncology, Holden Comprehensive Cancer Center, University of Iowa, Iowa City, IA 52242, USA; (C.R.O.); (B.G.A.); (P.C.G.); (D.R.S.)
- Department of Radiation Oncology, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, USA;
| | - Abu Shadat M. Noman
- Department of Biochemistry and Molecular Biology, The University of Chittagong, Chittagong 4331, Bangladesh;
- Department of Pathology, McGill University, Montreal, QC H3A 2B4, Canada
| | - Bryan G. Allen
- Free Radical & Radiation Biology Program, Department of Radiation Oncology, Holden Comprehensive Cancer Center, University of Iowa, Iowa City, IA 52242, USA; (C.R.O.); (B.G.A.); (P.C.G.); (D.R.S.)
- Department of Radiation Oncology, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, USA;
| | - Prabhat C. Goswami
- Free Radical & Radiation Biology Program, Department of Radiation Oncology, Holden Comprehensive Cancer Center, University of Iowa, Iowa City, IA 52242, USA; (C.R.O.); (B.G.A.); (P.C.G.); (D.R.S.)
- Department of Radiation Oncology, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, USA;
| | - Yousef Zakharia
- Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA; (Y.Z.); (V.M.)
| | - Varun Monga
- Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA; (Y.Z.); (V.M.)
| | - Douglas R. Spitz
- Free Radical & Radiation Biology Program, Department of Radiation Oncology, Holden Comprehensive Cancer Center, University of Iowa, Iowa City, IA 52242, USA; (C.R.O.); (B.G.A.); (P.C.G.); (D.R.S.)
- Department of Radiation Oncology, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, USA;
| | - John M. Buatti
- Department of Radiation Oncology, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, USA;
| | - Corinne E. Griguer
- Free Radical & Radiation Biology Program, Department of Radiation Oncology, Holden Comprehensive Cancer Center, University of Iowa, Iowa City, IA 52242, USA; (C.R.O.); (B.G.A.); (P.C.G.); (D.R.S.)
- Department of Radiation Oncology, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, USA;
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13
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Gollihue J, Norris C. Astrocyte mitochondria: Central players and potential therapeutic targets for neurodegenerative diseases and injury. Ageing Res Rev 2020; 59:101039. [PMID: 32105849 DOI: 10.1016/j.arr.2020.101039] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 01/23/2020] [Accepted: 02/23/2020] [Indexed: 01/16/2023]
Abstract
Mitochondrial function has long been the focus of many therapeutic strategies for ameliorating age-related neurodegeneration and cognitive decline. Historically, the role of mitochondria in non-neuronal cell types has been overshadowed by neuronal mitochondria, which are responsible for the bulk of oxidative metabolism in the brain. Despite this neuronal bias, mitochondrial function in glial cells, particularly astrocytes, is increasingly recognized to play crucial roles in overall brain metabolism, synaptic transmission, and neuronal protection. Changes in astrocytic mitochondrial function appear to be intimately linked to astrocyte activation/reactivity found in most all age-related neurodegenerative diseases. Here, we address the importance of mitochondrial function to astrocyte signaling and consider how mitochondria could contribute to both the detrimental and protective properties of activated astrocytes. Strategies for protecting astrocytic mitochondrial function, promoting bidirectional transfer of mitochondria between astrocytes and neurons, and transplanting healthy mitochondria to diseased nervous tissue are also discussed.
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14
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Afridi R, Kim JH, Rahman MH, Suk K. Metabolic Regulation of Glial Phenotypes: Implications in Neuron-Glia Interactions and Neurological Disorders. Front Cell Neurosci 2020; 14:20. [PMID: 32116564 PMCID: PMC7026370 DOI: 10.3389/fncel.2020.00020] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 01/23/2020] [Indexed: 12/12/2022] Open
Abstract
Glial cells are multifunctional, non-neuronal components of the central nervous system with diverse phenotypes that have gained much attention for their close involvement in neuroinflammation and neurodegenerative diseases. Glial phenotypes are primarily characterized by their structural and functional changes in response to various stimuli, which can be either neuroprotective or neurotoxic. The reliance of neurons on glial cells is essential to fulfill the energy demands of the brain for its proper functioning. Moreover, the glial cells perform distinct functions to regulate their own metabolic activities, as well as work in close conjunction with neurons through various secreted signaling or guidance molecules, thereby constituting a complex network of neuron-glial interactions in health and disease. The emerging evidence suggests that, in disease conditions, the metabolic alterations in the glial cells can induce structural and functional changes together with neuronal dysfunction indicating the importance of neuron-glia interactions in the pathophysiology of neurological disorders. This review covers the recent developments that implicate the regulation of glial phenotypic changes and its consequences on neuron-glia interactions in neurological disorders. Finally, we discuss the possibilities and challenges of targeting glial metabolism as a strategy to treat neurological disorders.
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Affiliation(s)
- Ruqayya Afridi
- BK21 Plus KNU Biomedical Convergence Program, Department of Pharmacology, Brain Science and Engineering Institute, School of Medicine, Kyungpook National University, Daegu, South Korea
| | - Jong-Heon Kim
- BK21 Plus KNU Biomedical Convergence Program, Department of Pharmacology, Brain Science and Engineering Institute, School of Medicine, Kyungpook National University, Daegu, South Korea
| | - Md Habibur Rahman
- BK21 Plus KNU Biomedical Convergence Program, Department of Pharmacology, Brain Science and Engineering Institute, School of Medicine, Kyungpook National University, Daegu, South Korea
| | - Kyoungho Suk
- BK21 Plus KNU Biomedical Convergence Program, Department of Pharmacology, Brain Science and Engineering Institute, School of Medicine, Kyungpook National University, Daegu, South Korea
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15
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Joalland B, Schmidt AB, Kabir MSH, Chukanov NV, Kovtunov KV, Koptyug IV, Hennig J, Hövener JB, Chekmenev EY. Pulse-Programmable Magnetic Field Sweeping of Parahydrogen-Induced Polarization by Side Arm Hydrogenation. Anal Chem 2020; 92:1340-1345. [PMID: 31800220 PMCID: PMC7436199 DOI: 10.1021/acs.analchem.9b04501] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Among the hyperpolarization techniques geared toward in vivo magnetic resonance imaging, parahydrogen-induced polarization (PHIP) shows promise due to its low cost and fast speed of contrast agent preparation. The synthesis of 13C-labeled, unsaturated precursors to perform PHIP by side arm hydrogenation has recently opened new possibilities for metabolic imaging owing to the biological compatibility of the reaction products, although the polarization transfer between the parahydrogen-derived protons and the 13C heteronucleus must yet be better understood, characterized, and eventually optimized. In this realm, a new experimental strategy incorporating pulse-programmable magnetic field sweeping and in situ detection has been developed. The approach is evaluated by measuring the 13C polarization of ethyl acetate-1-13C, i.e., the product of pairwise addition of parahydrogen to vinyl acetate-1-13C, resulting from zero-crossing magnetic field ramps of various durations, amplitudes, and step sizes. The results demonstrate (i) the profound effect these parameters have on the 1H to 13C polarization transfer efficiency and (ii) the high reproducibility of the technique.
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Affiliation(s)
- Baptiste Joalland
- Department of Chemistry, Integrative Biosciences (Ibio), Karmanos Cancer Institute (KCI), Wayne State University, Detroit, Michigan 48202, United States
| | - Andreas B. Schmidt
- Department of Radiology, Medical Physics, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department or Radiology and Neuroradiology, Section Biomedical Imaging, MOIN CC, University Medical Center Schleswig-Holstein, University of Kiel, Germany
| | - Mohammad S. H. Kabir
- Department of Chemistry, Integrative Biosciences (Ibio), Karmanos Cancer Institute (KCI), Wayne State University, Detroit, Michigan 48202, United States
| | - Nikita V. Chukanov
- International Tomography Center SB RAS, Institutskaya Street 3A, Novosibirsk 630090, Russia
- Novosibirsk State University, Pirogova Street 2, Novosibirsk 630090, Russia
| | - Kirill V. Kovtunov
- International Tomography Center SB RAS, Institutskaya Street 3A, Novosibirsk 630090, Russia
- Novosibirsk State University, Pirogova Street 2, Novosibirsk 630090, Russia
| | - Igor V. Koptyug
- International Tomography Center SB RAS, Institutskaya Street 3A, Novosibirsk 630090, Russia
- Novosibirsk State University, Pirogova Street 2, Novosibirsk 630090, Russia
| | - Jürgen Hennig
- Department of Radiology, Medical Physics, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Jan-Bernd Hövener
- Department or Radiology and Neuroradiology, Section Biomedical Imaging, MOIN CC, University Medical Center Schleswig-Holstein, University of Kiel, Germany
| | - Eduard Y. Chekmenev
- Department of Chemistry, Integrative Biosciences (Ibio), Karmanos Cancer Institute (KCI), Wayne State University, Detroit, Michigan 48202, United States
- Russian Academy of Sciences, Leninskiy Prospekt 14, Moscow 119991, Russia
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16
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Gemeinhardt ME, Limbach MN, Gebhardt TR, Eriksson CW, Eriksson SL, Lindale JR, Goodson EA, Warren WS, Chekmenev EY, Goodson BM. “Direct”
13
C Hyperpolarization of
13
C‐Acetate by MicroTesla NMR Signal Amplification by Reversible Exchange (SABRE). Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201910506] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Max E. Gemeinhardt
- Department of Chemistry and Biochemistry Southern Illinois University Carbondale IL 62901 USA
| | - Miranda N. Limbach
- Department of Chemistry and Biochemistry Southern Illinois University Carbondale IL 62901 USA
| | - Thomas R. Gebhardt
- Department of Chemistry and Biochemistry Southern Illinois University Carbondale IL 62901 USA
| | - Clark W. Eriksson
- Department of Biomedical Engineering University of Virginia Charlottesville VA USA
| | - Shannon L. Eriksson
- Department of Chemistry Duke University Durham NC USA
- School of Medicine Duke University Durham NC USA
| | | | | | - Warren S. Warren
- Department of Chemistry Duke University Durham NC USA
- James B. Duke Professor, Physics Chemistry, Radiology, and Biomedical Engineering; Director Center for Molecular and Biomolecular Imaging Duke University Durham NC USA
| | - Eduard Y. Chekmenev
- Department of Chemistry Karmanos Cancer Institute (KCI) Integrative Biosciences (Ibio) Wayne State University Detroit MI 48202 USA
- Russian Academy of Sciences (RAS) Moscow 119991 Russia
| | - Boyd M. Goodson
- Department of Chemistry and Biochemistry Southern Illinois University Carbondale IL 62901 USA
- Materials Technology Center Southern Illinois University Carbondale IL 62901 USA
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17
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Gemeinhardt ME, Limbach MN, Gebhardt TR, Eriksson CW, Eriksson SL, Lindale JR, Goodson EA, Warren WS, Chekmenev EY, Goodson BM. "Direct" 13 C Hyperpolarization of 13 C-Acetate by MicroTesla NMR Signal Amplification by Reversible Exchange (SABRE). Angew Chem Int Ed Engl 2019; 59:418-423. [PMID: 31661580 DOI: 10.1002/anie.201910506] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 10/16/2019] [Indexed: 01/06/2023]
Abstract
Herein, we demonstrate "direct" 13 C hyperpolarization of 13 C-acetate via signal amplification by reversible exchange (SABRE). The standard SABRE homogeneous catalyst [Ir-IMes; [IrCl(COD)(IMes)], (IMes=1,3-bis(2,4,6-trimethylphenyl), imidazole-2-ylidene; COD=cyclooctadiene)] was first activated in the presence of an auxiliary substrate (pyridine) in alcohol. Following addition of sodium 1-13 C-acetate, parahydrogen bubbling within a microtesla magnetic field (i.e. under conditions of SABRE in shield enables alignment transfer to heteronuclei, SABRE-SHEATH) resulted in positive enhancements of up to ≈100-fold in the 13 C NMR signal compared to thermal equilibrium at 9.4 T. The present results are consistent with a mechanism of "direct" transfer of spin order from parahydrogen to 13 C spins of acetate weakly bound to the catalyst, under conditions of fast exchange with respect to the 13 C acetate resonance, but we find that relaxation dynamics at microtesla fields alter the optimal matching from the traditional SABRE-SHEATH picture. Further development of this approach could lead to new ways to rapidly, cheaply, and simply hyperpolarize a broad range of substrates (e.g. metabolites with carboxyl groups) for various applications, including biomedical NMR and MRI of cellular and in vivo metabolism.
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Affiliation(s)
- Max E Gemeinhardt
- Department of Chemistry and Biochemistry, Southern Illinois University, Carbondale, IL, 62901, USA
| | - Miranda N Limbach
- Department of Chemistry and Biochemistry, Southern Illinois University, Carbondale, IL, 62901, USA
| | - Thomas R Gebhardt
- Department of Chemistry and Biochemistry, Southern Illinois University, Carbondale, IL, 62901, USA
| | - Clark W Eriksson
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, USA
| | - Shannon L Eriksson
- Department of Chemistry, Duke University, Durham, NC, USA.,School of Medicine, Duke University, Durham, NC, USA
| | | | | | - Warren S Warren
- Department of Chemistry, Duke University, Durham, NC, USA.,James B. Duke Professor, Physics, Chemistry, Radiology, and Biomedical Engineering; Director, Center for Molecular and Biomolecular Imaging, Duke University, Durham, NC, USA
| | - Eduard Y Chekmenev
- Department of Chemistry, Karmanos Cancer Institute (KCI), Integrative Biosciences (Ibio), Wayne State University, Detroit, MI, 48202, USA.,Russian Academy of Sciences (RAS), Moscow, 119991, Russia
| | - Boyd M Goodson
- Department of Chemistry and Biochemistry, Southern Illinois University, Carbondale, IL, 62901, USA.,Materials Technology Center, Southern Illinois University, Carbondale, IL, 62901, USA
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18
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Korchak S, Emondts M, Mamone S, Blümich B, Glöggler S. Production of highly concentrated and hyperpolarized metabolites within seconds in high and low magnetic fields. Phys Chem Chem Phys 2019; 21:22849-22856. [DOI: 10.1039/c9cp05227e] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
We introduce two experiments that allow for the rapid production of hyperpolarized metabolites. More than 50% 13C polarization in 50 mM concentrations is achieved. This can be translated to portable low field NMR devices.
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Affiliation(s)
- Sergey Korchak
- NMR Signal Enhancement Group Max-Planck-Institute for Biophysical Chemistry
- 37077 Göttingen
- Germany
- Center for Biostructural Imaging of Neurodegeneration, Von-Siebold-Straße 3A
- 37075 Göttingen
| | - Meike Emondts
- DWI-Leibniz Institute for Interactive Materials
- D-52056 Aachen
- Germany
- Institut für Technische Chemie und Makromolekulare Chemie
- RWTH-Aachen University
| | - Salvatore Mamone
- NMR Signal Enhancement Group Max-Planck-Institute for Biophysical Chemistry
- 37077 Göttingen
- Germany
- Center for Biostructural Imaging of Neurodegeneration, Von-Siebold-Straße 3A
- 37075 Göttingen
| | - Bernhard Blümich
- Institut für Technische Chemie und Makromolekulare Chemie
- RWTH-Aachen University
- Worringerweg 2
- Germany
| | - Stefan Glöggler
- NMR Signal Enhancement Group Max-Planck-Institute for Biophysical Chemistry
- 37077 Göttingen
- Germany
- Center for Biostructural Imaging of Neurodegeneration, Von-Siebold-Straße 3A
- 37075 Göttingen
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19
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McDougal DH, Darpolor MM, DuVall MA, Sutton EF, Morrison CD, Gadde KM, Redman LM, Carmichael OT. Glial acetate metabolism is increased following a 72-h fast in metabolically healthy men and correlates with susceptibility to hypoglycemia. Acta Diabetol 2018; 55:1029-1036. [PMID: 29931424 PMCID: PMC6153507 DOI: 10.1007/s00592-018-1180-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 06/11/2018] [Indexed: 12/02/2022]
Abstract
AIMS Prior exposure to insulin-induced hypoglycemia was shown to increase glial acetate metabolism (GAM) during subsequent exposure to hypoglycemia in diabetic individuals. However, it remained unclear whether this effect was dependent on the disease state or the antecedent cause of hypoglycemia. We aimed to establish whether exposure to fasting-induced hypoglycemia was sufficient to produce alterations in GAM in non-diabetic individuals. METHODS GAM was measured via carbon-13 magnetic resonance spectroscopy during infusion of [1-13C] acetate before and after a 72-h fast in six metabolically healthy men. All participants were male, aged 18-40 years, with a Body Mass Index of 20.0-27.9 kg/m2, who consented to reside at Pennington Biomedical Research Center for 4 days. The main outcome measure was the percent enhancement of cerebral [1-13C] bicarbonate (the primary metabolic byproduct of glial oxidation of [1-13C] acetate). Continuous glucose monitoring was used to measure hypoglycemic episodes during the 72-h fast. RESULTS As expected, 72 h of fasting significantly reduced blood glucose levels and resulted in a high frequency of hypoglycemic episodes. Steady-state GAM increased from 53.5 ± 3.7 to 61.9 ± 1.7% following the 72-h fast (p = 0.005). This increase correlated with greater duration of hypoglycemia experienced during the fast (r = 0.967). In addition, subjects with greater GAM at baseline experienced a greater increase in the duration of hypoglycemia experienced during the 72-h fast (r = 0.979). CONCLUSIONS GAM has potential as a biomarker for susceptibility to hypoglycemic episodes. TRAIL REGISTRATION Clinicaltrials.gov ID: NCT02690168.
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Affiliation(s)
| | | | | | - Elizabeth Frost Sutton
- Pennington Biomedical Research Center, Baton Rouge, LA, 70808, USA
- Magee-Womens Research Institute, 204 Craft Ave, Pittsburgh, PA, 15213, USA
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20
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Eraso-Pichot A, Brasó-Vives M, Golbano A, Menacho C, Claro E, Galea E, Masgrau R. GSEA of mouse and human mitochondriomes reveals fatty acid oxidation in astrocytes. Glia 2018; 66:1724-1735. [PMID: 29575211 DOI: 10.1002/glia.23330] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 02/27/2018] [Accepted: 03/05/2018] [Indexed: 12/18/2022]
Abstract
The prevalent view in neuroenergetics is that glucose is the main brain fuel, with neurons being mostly oxidative and astrocytes glycolytic. Evidence supporting that astrocyte mitochondria are functional has been overlooked. Here we sought to determine what is unique about astrocyte mitochondria by performing unbiased statistical comparisons of the mitochondriome in astrocytes and neurons. Using MitoCarta, a compendium of mitochondrial proteins, together with transcriptomes of mouse neurons and astrocytes, we generated cell-specific databases of nuclear genes encoding for mitochondrion proteins, ranked according to relative expression. Standard and in-house Gene Set Enrichment Analyses (GSEA) of five mouse transcriptomes revealed that genes encoding for enzymes involved in fatty acid oxidation (FAO) and amino acid catabolism are consistently more expressed in astrocytes than in neurons. FAO and oxidative-metabolism-related genes are also up-regulated in human cortical astrocytes versus the whole cortex, and in adult astrocytes versus fetal astrocytes. We thus present the first evidence of FAO in human astrocytes. Further, as shown in vitro, FAO coexists with glycolysis in astrocytes and is inhibited by glutamate. Altogether, these analyses provide arguments against the glucose-centered view of energy metabolism in astrocytes and reveal mitochondria as specialized organelles in these cells.
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Affiliation(s)
- Abel Eraso-Pichot
- Departament de Bioquímica i Biologia Molecular, Unitat de Bioquímica de Medicina, i Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, 08193, Spain
| | - Marina Brasó-Vives
- Institute of Evolutionary Biology (Universitat Pompeu Fabra - CSIC), PRBB, Barcelona, 08003, Spain
| | - Arantxa Golbano
- Departament de Bioquímica i Biologia Molecular, Unitat de Bioquímica de Medicina, i Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, 08193, Spain
| | - Carmen Menacho
- Departament de Bioquímica i Biologia Molecular, Unitat de Bioquímica de Medicina, i Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, 08193, Spain
| | - Enrique Claro
- Departament de Bioquímica i Biologia Molecular, Unitat de Bioquímica de Medicina, i Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, 08193, Spain
| | - Elena Galea
- Departament de Bioquímica i Biologia Molecular, Unitat de Bioquímica de Medicina, i Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, 08193, Spain.,ICREA, Passeig Lluís Companys 23, Barcelona, 08010, Spain
| | - Roser Masgrau
- Departament de Bioquímica i Biologia Molecular, Unitat de Bioquímica de Medicina, i Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, 08193, Spain
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21
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Determining the Rate of Carbonic Anhydrase Reaction in the Human Brain. Sci Rep 2018; 8:2328. [PMID: 29396553 PMCID: PMC5797079 DOI: 10.1038/s41598-018-20746-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 01/22/2018] [Indexed: 01/13/2023] Open
Abstract
Carbonic anhydrase plays important role in life. This study sought to demonstrate the feasibility of detecting carbonic anhydrase activity in the human brain in vivo. After oral administration of [U-13C6]glucose, 13C saturation transfer experiments were performed with interleaved control spectra and carbon dioxide saturation spectra. Proton nuclear Overhauser effect pulses were used to increase signal to noise ratio; no proton decoupling was applied. Results showed that the 13C signal of bicarbonate was reduced by 72% ± 0.03 upon saturating carbon dioxide. The unidirectional dehydration rate constant of the carbonic anhydrase reaction was found to be 0.28 ± 0.02 sec−1 in the human brain. These findings demonstrate the feasibility of measuring carbonic anhydrase activity in vivo in the human brain, which makes it possible to characterize this important enzyme in patients with brain disorders.
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22
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Neuronal control of astrocytic respiration through a variant of the Crabtree effect. Proc Natl Acad Sci U S A 2018; 115:1623-1628. [PMID: 29378955 DOI: 10.1073/pnas.1716469115] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Aerobic glycolysis is a phenomenon that in the long term contributes to synaptic formation and growth, is reduced by normal aging, and correlates with amyloid beta deposition. Aerobic glycolysis starts within seconds of neural activity and it is not obvious why energetic efficiency should be compromised precisely when energy demand is highest. Using genetically encoded FRET nanosensors and real-time oxygen measurements in culture and in hippocampal slices, we show here that astrocytes respond to physiological extracellular K+ with an acute rise in cytosolic ATP and a parallel inhibition of oxygen consumption, explained by glycolytic stimulation via the Na+-bicarbonate cotransporter NBCe1. This control of mitochondrial respiration via glycolysis modulation is reminiscent of a phenomenon previously described in proliferating cells, known as the Crabtree effect. Fast brain aerobic glycolysis may be interpreted as a strategy whereby neurons manipulate neighboring astrocytes to obtain oxygen, thus maximizing information processing.
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23
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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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24
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Salzillo TC, Hu J, Nguyen L, Whiting N, Lee J, Weygand J, Dutta P, Pudakalakatti S, Millward NZ, Gammon ST, Lang FF, Heimberger AB, Bhattacharya PK. Interrogating Metabolism in Brain Cancer. Magn Reson Imaging Clin N Am 2017; 24:687-703. [PMID: 27742110 DOI: 10.1016/j.mric.2016.07.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This article reviews existing and emerging techniques of interrogating metabolism in brain cancer from well-established proton magnetic resonance spectroscopy to the promising hyperpolarized metabolic imaging and chemical exchange saturation transfer and emerging techniques of imaging inflammation. Some of these techniques are at an early stage of development and clinical trials are in progress in patients to establish the clinical efficacy. It is likely that in vivo metabolomics and metabolic imaging is the next frontier in brain cancer diagnosis and assessing therapeutic efficacy; with the combined knowledge of genomics and proteomics a complete understanding of tumorigenesis in brain might be achieved.
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Affiliation(s)
- Travis C Salzillo
- Department of Cancer Systems Imaging, MD Anderson Cancer Center, The University of Texas, Houston, TX, USA; The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Jingzhe Hu
- Department of Cancer Systems Imaging, MD Anderson Cancer Center, The University of Texas, Houston, TX, USA; Department of Bioengineering, Rice University, Houston, TX, USA
| | - Linda Nguyen
- The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Nicholas Whiting
- Department of Cancer Systems Imaging, MD Anderson Cancer Center, The University of Texas, Houston, TX, USA
| | - Jaehyuk Lee
- Department of Cancer Systems Imaging, MD Anderson Cancer Center, The University of Texas, Houston, TX, USA
| | - Joseph Weygand
- Department of Cancer Systems Imaging, MD Anderson Cancer Center, The University of Texas, Houston, TX, USA; The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Prasanta Dutta
- Department of Cancer Systems Imaging, MD Anderson Cancer Center, The University of Texas, Houston, TX, USA
| | - Shivanand Pudakalakatti
- Department of Cancer Systems Imaging, MD Anderson Cancer Center, The University of Texas, Houston, TX, USA
| | - Niki Zacharias Millward
- Department of Cancer Systems Imaging, MD Anderson Cancer Center, The University of Texas, Houston, TX, USA
| | - Seth T Gammon
- Department of Cancer Systems Imaging, MD Anderson Cancer Center, The University of Texas, Houston, TX, USA
| | - Frederick F Lang
- Department of Neurosurgery, MD Anderson Cancer Center, The University of Texas, Houston, TX, USA
| | - Amy B Heimberger
- Department of Neurosurgery, MD Anderson Cancer Center, The University of Texas, Houston, TX, USA
| | - Pratip K Bhattacharya
- Department of Cancer Systems Imaging, MD Anderson Cancer Center, The University of Texas, Houston, TX, USA; The University of Texas Health Science Center at Houston, Houston, TX, USA.
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25
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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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26
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Haroon E, Miller AH. Inflammation Effects on Brain Glutamate in Depression: Mechanistic Considerations and Treatment Implications. Curr Top Behav Neurosci 2017; 31:173-198. [PMID: 27830574 DOI: 10.1007/7854_2016_40] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
There has been increasing interest in the role of glutamate in mood disorders, especially given the profound effect of the glutamate receptor antagonist ketamine in improving depressive symptoms in patients with treatment-resistant depression. One pathway by which glutamate alterations may occur in mood disorders involves inflammation. Increased inflammation has been observed in a significant subgroup of patients with mood disorders, and inflammatory cytokines have been shown to influence glutamate metabolism through effects on astrocytes and microglia. In addition, the administration of the inflammatory cytokine interferon-alpha has been shown to increase brain glutamate in the basal ganglia and dorsal anterior cingulate cortex as measured by magnetic resonance spectroscopy (MRS). Moreover, MRS studies in patients with major depressive disorder have revealed that increased markers of inflammation including C-reactive protein correlate with increased basal ganglia glutamate, which in turn was associated with anhedonia and psychomotor retardation. Finally, human and laboratory animal studies have shown that the response to glutamate antagonists such as ketamine is predicted by increased inflammatory cytokines. Taken together, these data make a strong case that inflammation may influence glutamate metabolism to alter behavior, leading to depressive symptoms including anhedonia and psychomotor slowing.
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Affiliation(s)
- Ebrahim Haroon
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, 1365-B Clifton Road., 5th Floor, B5101, Atlanta, GA, 30322, USA
| | - Andrew H Miller
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, 1365-B Clifton Road., 5th Floor, B5101, Atlanta, GA, 30322, USA.
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27
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Hyperpolarized MRS: New tool to study real-time brain function and metabolism. Anal Biochem 2016; 529:270-277. [PMID: 27665679 DOI: 10.1016/j.ab.2016.09.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 08/31/2016] [Accepted: 09/21/2016] [Indexed: 11/23/2022]
Abstract
The advent of dissolution dynamic nuclear polarization (DNP) led to the emergence of a new kind of magnetic resonance (MR) measurements providing the opportunity to probe metabolism in vivo in real time. It has been shown that, following the injection of hyperpolarized substrates prepared using dissolution DNP, specific metabolic bioprobes that can be used to differentiate between healthy and pathological tissue in preclinical and clinical studies can be readily detected by MR thanks to the tremendous signal enhancement. The present article aims at reviewing the studies of cerebral function and metabolism based on the use of hyperpolarized MR. The constraints and future opportunities that this technology could offer are discussed.
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28
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Shchepin RV, Barskiy DA, Coffey AM, Manzanera Esteve IV, Chekmenev EY. Efficient Synthesis of Molecular Precursors for Para‐Hydrogen‐Induced Polarization of Ethyl Acetate‐1‐
13
C and Beyond. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201600521] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Roman V. Shchepin
- Department of Radiology Vanderbilt University Institute of Imaging Science (VUIIS), Department of Biomedical Engineering, Vanderbilt-Ingram Cancer Center (VICC), Vanderbilt University Nashville TN 37232 USA
| | - Danila A. Barskiy
- Department of Radiology Vanderbilt University Institute of Imaging Science (VUIIS), Department of Biomedical Engineering, Vanderbilt-Ingram Cancer Center (VICC), Vanderbilt University Nashville TN 37232 USA
| | - Aaron M. Coffey
- Department of Radiology Vanderbilt University Institute of Imaging Science (VUIIS), Department of Biomedical Engineering, Vanderbilt-Ingram Cancer Center (VICC), Vanderbilt University Nashville TN 37232 USA
| | - Isaac V. Manzanera Esteve
- Department of Radiology Vanderbilt University Institute of Imaging Science (VUIIS), Department of Biomedical Engineering, Vanderbilt-Ingram Cancer Center (VICC), Vanderbilt University Nashville TN 37232 USA
| | - Eduard Y. Chekmenev
- Department of Radiology Vanderbilt University Institute of Imaging Science (VUIIS), Department of Biomedical Engineering, Vanderbilt-Ingram Cancer Center (VICC), Vanderbilt University Nashville TN 37232 USA
- Russian Academy of Sciences 119991 Moscow Russia
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29
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Shchepin RV, Barskiy DA, Coffey AM, Manzanera Esteve IV, Chekmenev EY. Efficient Synthesis of Molecular Precursors for Para-Hydrogen-Induced Polarization of Ethyl Acetate-1-(13) C and Beyond. Angew Chem Int Ed Engl 2016; 55:6071-4. [PMID: 27061815 DOI: 10.1002/anie.201600521] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 02/18/2016] [Indexed: 12/15/2022]
Abstract
A scalable and versatile methodology for production of vinylated carboxylic compounds with (13) C isotopic label in C1 position is described. It allowed synthesis of vinyl acetate-1-(13) C, which is a precursor for preparation of (13) C hyperpolarized ethyl acetate-1-(13) C, which provides a convenient vehicle for potential in vivo delivery of hyperpolarized acetate to probe metabolism in living organisms. Kinetics of vinyl acetate molecular hydrogenation and polarization transfer from para-hydrogen to (13) C via magnetic field cycling were investigated. Nascent proton nuclear spin polarization (%PH ) of ca. 3.3 % and carbon-13 polarization (%P13C ) of ca. 1.8 % were achieved in ethyl acetate utilizing 50 % para-hydrogen corresponding to ca. 50 % polarization transfer efficiency. The use of nearly 100% para-hydrogen and the improvements of %PH of para-hydrogen-nascent protons may enable production of (13) C hyperpolarized contrast agents with %P13C of 20-50 % in seconds using this chemistry.
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Affiliation(s)
- Roman V Shchepin
- Department of Radiology, Vanderbilt University Institute of Imaging Science (VUIIS), Department of Biomedical Engineering, Vanderbilt-Ingram Cancer Center (VICC), Vanderbilt University, Nashville, TN, 37232, USA
| | - Danila A Barskiy
- Department of Radiology, Vanderbilt University Institute of Imaging Science (VUIIS), Department of Biomedical Engineering, Vanderbilt-Ingram Cancer Center (VICC), Vanderbilt University, Nashville, TN, 37232, USA
| | - Aaron M Coffey
- Department of Radiology, Vanderbilt University Institute of Imaging Science (VUIIS), Department of Biomedical Engineering, Vanderbilt-Ingram Cancer Center (VICC), Vanderbilt University, Nashville, TN, 37232, USA
| | - Isaac V Manzanera Esteve
- Department of Radiology, Vanderbilt University Institute of Imaging Science (VUIIS), Department of Biomedical Engineering, Vanderbilt-Ingram Cancer Center (VICC), Vanderbilt University, Nashville, TN, 37232, USA
| | - Eduard Y Chekmenev
- Department of Radiology, Vanderbilt University Institute of Imaging Science (VUIIS), Department of Biomedical Engineering, Vanderbilt-Ingram Cancer Center (VICC), Vanderbilt University, Nashville, TN, 37232, USA. .,Russian Academy of Sciences, 119991, Moscow, Russia.
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30
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Glutamate and ATP at the Interface Between Signaling and Metabolism in Astroglia: Examples from Pathology. Neurochem Res 2016; 42:19-34. [PMID: 26915104 DOI: 10.1007/s11064-016-1848-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2016] [Revised: 01/21/2016] [Accepted: 01/22/2016] [Indexed: 12/17/2022]
Abstract
Glutamate is the main excitatory transmitter in the brain, while ATP represents the most important energy currency in any living cell. Yet, these chemicals play an important role in both processes, enabling them with dual-acting functions in metabolic and intercellular signaling pathways. Glutamate can fuel ATP production, while ATP can act as a transmitter in intercellular signaling. We discuss the interface between glutamate and ATP in signaling and metabolism of astrocytes. Not only do glutamate and ATP cross each other's paths in physiology of the brain, but they also do so in its pathology. We present the fabric of this process in (patho)physiology through the discussion of synthesis and metabolism of ATP and glutamate in astrocytes as well as by providing a general description of astroglial receptors for these molecules along with the downstream signaling pathways that may be activated. It is astroglial receptors for these dual-acting molecules that could hold a key for medical intervention in pathological conditions. We focus on two examples disclosing the role of activation of astroglial ATP and glutamate receptors in pathology of two kinds of brain tissue, gray matter and white matter, respectively. Interventions at the interface of metabolism and signaling show promise for translational medicine.
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31
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de Graaf RA, De Feyter HM, Rothman DL. High-sensitivity, broadband-decoupled (13) C MR spectroscopy in humans at 7T using two-dimensional heteronuclear single-quantum coherence. Magn Reson Med 2015; 74:903-14. [PMID: 25264872 PMCID: PMC4377311 DOI: 10.1002/mrm.25470] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 08/11/2014] [Accepted: 08/31/2014] [Indexed: 11/09/2022]
Abstract
PURPOSE Carbon-13 ((13) C) magnetic resonance spectroscopy (MRS) has an intrinsically low NMR sensitivity that often leads to large acquisition volumes or long scan times. While the use of higher magnetic fields can overcome the sensitivity limitations, high radiofrequency (RF) power deposition associated with proton-decoupling limits the achievable gain. Two-dimensional (2D) heteronuclear single quantum coherence (HSQC) MRS is a method that uses the high chemical specificity of (13) C MRS while retaining the high sensitivity of (1) H detection. Due to the 2D nature of the method, proton-decoupled (13) C MR spectra can be obtained without the use of high-powered decoupling pulses. METHODS A novel three-dimensional (3D) localized 2D HSQC method based on 3D STEAM localization is presented and implemented at 7T. The low RF power deposition of the method allows TR variation along the indirect dimension which, in combination with controlled aliasing, leads to an acceleration of 11.8 relative to a standard 2D NMR acquisition. RESULTS Artifact-free, high-quality and high-sensitivity 2D HSQC spectra were obtained for all subjects in 19 min from a small (9 mL) volume placed in the leg adipose tissue. Complete proton decoupling was achieved along the indirect (13) C dimension despite the absence of broadband proton-decoupling pulses. The high chemical specificity along the indirect (13) C dimension allowed the detection of 19 unique resonances from which the lipids could be characterized in terms of saturation and omega-6/omega-3 fatty acid ratio. CONCLUSION It has been demonstrated that high-quality 2D HSQC NMR spectra can be acquired from human adipose tissue at 7T. The HSQC method is methodologically simple and robust and is flexible regarding trade-offs between temporal and spectral resolution. 2D HSQC has a strong potential to become a default method in natural-abundance or (13) C-enriched studies of human metabolism in vivo.
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Affiliation(s)
- Robin A de Graaf
- Department of Diagnostic Radiology, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Henk M De Feyter
- Department of Diagnostic Radiology, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Douglas L Rothman
- Department of Diagnostic Radiology, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
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32
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Kalpathy-Cramer J, Gerstner ER, Emblem KE, Andronesi O, Rosen B. Advanced magnetic resonance imaging of the physical processes in human glioblastoma. Cancer Res 2015; 74:4622-4637. [PMID: 25183787 DOI: 10.1158/0008-5472.can-14-0383] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The most common malignant primary brain tumor, glioblastoma multiforme (GBM) is a devastating disease with a grim prognosis. Patient survival is typically less than two years and fewer than 10% of patients survive more than five years. Magnetic resonance imaging (MRI) can have great utility in the diagnosis, grading, and management of patients with GBM as many of the physical manifestations of the pathologic processes in GBM can be visualized and quantified using MRI. Newer MRI techniques such as dynamic contrast enhanced and dynamic susceptibility contrast MRI provide functional information about the tumor hemodynamic status. Diffusion MRI can shed light on tumor cellularity and the disruption of white matter tracts in the proximity of tumors. MR spectroscopy can be used to study new tumor tissue markers such as IDH mutations. MRI is helping to noninvasively explore the link between the molecular basis of gliomas and the imaging characteristics of their physical processes. We, here, review several approaches to MR-based imaging and discuss the potential for these techniques to quantify the physical processes in glioblastoma, including tumor cellularity and vascularity, metabolite expression, and patterns of tumor growth and recurrence. We conclude with challenges and opportunities for further research in applying physical principles to better understand the biologic process in this deadly disease. See all articles in this Cancer Research section, "Physics in Cancer Research."
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Affiliation(s)
- Jayashree Kalpathy-Cramer
- Athinoula A. Martinos Center for Biomedical Imaging, Departments of Radiology, Oslo University Hospital, Oslo, Norway
| | - Elizabeth R Gerstner
- Neurology, Massachusetts General Hospital and Harvard Medical School, Oslo University Hospital, Oslo, Norway
| | - Kyrre E Emblem
- Athinoula A. Martinos Center for Biomedical Imaging, Departments of Radiology, Oslo University Hospital, Oslo, Norway.,The Intervention Centre, Oslo University Hospital, Oslo, Norway
| | - Ovidiu Andronesi
- Athinoula A. Martinos Center for Biomedical Imaging, Departments of Radiology, Oslo University Hospital, Oslo, Norway
| | - Bruce Rosen
- Athinoula A. Martinos Center for Biomedical Imaging, Departments of Radiology, Oslo University Hospital, Oslo, Norway
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33
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Shulman RG, Hyder F, Rothman DL. Insights from neuroenergetics into the interpretation of functional neuroimaging: an alternative empirical model for studying the brain's support of behavior. J Cereb Blood Flow Metab 2014; 34:1721-35. [PMID: 25160670 PMCID: PMC4269754 DOI: 10.1038/jcbfm.2014.145] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 06/12/2014] [Accepted: 07/21/2014] [Indexed: 02/05/2023]
Abstract
Functional neuroimaging measures quantitative changes in neurophysiological parameters coupled to neuronal activity during observable behavior. These results have usually been interpreted by assuming that mental causation of behavior arises from the simultaneous actions of distinct psychological mechanisms or modules. However, reproducible localization of these modules in the brain using functional magnetic resonance imaging (MRI) and positron emission tomography (PET) imaging has been elusive other than for sensory systems. In this paper, we show that neuroenergetic studies using PET, calibrated functional magnetic resonance imaging (fMRI), (13)C magnetic resonance spectroscopy, and electrical recordings do not support the standard approach, which identifies the location of mental modules from changes in brain activity. Of importance in reaching this conclusion is that changes in neuronal activities underlying the fMRI signal are many times smaller than the high ubiquitous, baseline neuronal activity, or energy in resting, awake humans. Furthermore, the incremental signal depends on the baseline activity contradicting theoretical assumptions about linearity and insertion of mental modules. To avoid these problems, while making use of these valuable results, we propose that neuroimaging should be used to identify observable brain activities that are necessary for a person's observable behavior rather than being used to seek hypothesized mental processes.
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Affiliation(s)
- Robert G Shulman
- Magnetic Resonance Research Center, Yale University, New Haven, Connecticut, USA
| | - Fahmeed Hyder
- Magnetic Resonance Research Center, Yale University, New Haven, Connecticut, USA
- Departments of Diagnostic Radiology, Yale University, New Haven, Connecticut, USA
- Biomedical Engineering, Yale University, New Haven, Connecticut, USA
- Quantitative Neuroscience with Magnetic Resonance Core Center, Yale University, New Haven, Connecticut, USA
| | - Douglas L Rothman
- Magnetic Resonance Research Center, Yale University, New Haven, Connecticut, USA
- Departments of Diagnostic Radiology, Yale University, New Haven, Connecticut, USA
- Biomedical Engineering, Yale University, New Haven, Connecticut, USA
- Quantitative Neuroscience with Magnetic Resonance Core Center, Yale University, New Haven, Connecticut, USA
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Sayre NL, Chen Y, Sifuentes M, Stoveken B, Lechleiter JD. Purinergic receptor stimulation decreases ischemic brain damage by energizing astrocyte mitochondria. ADVANCES IN NEUROBIOLOGY 2014; 11:121-50. [PMID: 25236727 DOI: 10.1007/978-3-319-08894-5_7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
As a leading cause of death in the world, cerebral ischemic stroke has limited treatment options. The lack of glucose and oxygen after stroke is particularly harmful in the brain because neuronal metabolism accounts for significantly more energy consumption per gram of body weight compared to other organs. Our laboratory has identified mitochondrial metabolism of astrocytes to be a key target for pharmacologic intervention, not only because astrocytes play a central role in regulating brain metabolism, but also because they are essential for neuronal health and support. Here we review current literature pertaining to the pathobiology of stroke, along with the role of astrocytes and metabolism in stroke. We also discuss our research, which has revealed that pharmacologic stimulation of metabotropic P2Y1 receptor signaling in astrocytes can increase mitochondrial energy production and also reduce damage after stroke.
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Affiliation(s)
- Naomi L Sayre
- Department of Cellular and Structural Biology, University of Texas Health Science Center San Antonio, 7703 Floyd Curl Drive, San Antonio, TX, 78229, USA
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Shchepin RV, Pham W, Chekmenev EY. Dephosphorylation and biodistribution of 1-¹³C-phospholactate in vivo. J Labelled Comp Radiopharm 2014; 57:517-24. [PMID: 24995802 DOI: 10.1002/jlcr.3207] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2014] [Revised: 04/07/2014] [Accepted: 04/20/2014] [Indexed: 11/09/2022]
Abstract
Here, we present a new approach for the delivery of a metabolic contrast agent for in vivo molecular imaging. The use of a phosphate-protecting group that facilitates parahydrogen-induced polarization of 1-(13)C-phospholactate potentially enables the in vivo administration of a hydrogenated hyperpolarized adduct. When injected, nonhyperpolarized 1-(13)C-phospholactate is retained in the vasculature during its metabolic conversion to 1-(13)C-lactate by blood phosphatases as demonstrated here using a mucin 1 mouse model of breast cancer and ex vivo high-resolution (13)C NMR. This multisecond process is a suitable mechanism for the delivery of relatively short-lived (13)C and potentially (15)N hyperpolarized contrast agents using -OH phosphorylated small molecules, which is demonstrated here for the first time as an example of 1-(13)C-phospholactate. Through this approach, DL-1-(13)C-lactate is taken up by tissues and organs including the liver, kidneys, brain, heart, and tumors according to a timescale amenable to hyperpolarized magnetic resonance imaging.
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Affiliation(s)
- Roman V Shchepin
- Vanderbilt University Institute of Imaging Science (VUIIS), Department of Radiology, Nashville, TN,, 37232, USA
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36
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Abstract
In vitro and in vivo studies have shown that glutamate can be oxidized for energy by brain astrocytes. The ability to harvest the energy from glutamate provides astrocytes with a mechanism to offset the high ATP cost of the uptake of glutamate from the synaptic cleft. This brief review focuses on oxidative metabolism of glutamate by astrocytes, the specific pathways involved in the complete oxidation of glutamate and the energy provided by each reaction.
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Affiliation(s)
- Mary C. McKenna
- Department of Pediatrics and Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, USA
- *Correspondence: Mary C. McKenna, Department of Pediatrics and Program in Neuroscience, University of Maryland School of Medicine, 655 West Baltimore Street, Room 13-019 BRB, Baltimore, MD 21201, USA e-mail:
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Ramadan S, Lin A, Stanwell P. Glutamate and glutamine: a review of in vivo MRS in the human brain. NMR IN BIOMEDICINE 2013; 26:1630-46. [PMID: 24123328 PMCID: PMC3849600 DOI: 10.1002/nbm.3045] [Citation(s) in RCA: 179] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 08/08/2013] [Accepted: 09/08/2013] [Indexed: 05/21/2023]
Abstract
Our understanding of the roles that the amino acids glutamate (Glu) and glutamine (Gln) play in the mammalian central nervous system has increased rapidly in recent times. Many conditions are known to exhibit a disturbance in Glu-Gln equilibrium, and the exact relationships between these changed conditions and these amino acids are not fully understood. This has led to increased interest in Glu/Gln quantitation in the human brain in an array of conditions (e.g. mental illness, tumor, neuro-degeneration) as well as in normal brain function. Accordingly, this review has been undertaken to describe the increasing number of in vivo techniques available to study Glu and Gln separately, or pooled as 'Glx'. The present MRS methods used to assess Glu and Gln vary in approach, complexity, and outcome, thus the focus of this review is on a description of MRS acquisition approaches, and an indication of relative utility of each technique rather than brain pathologies associated with Glu and/or Gln perturbation. Consequently, this review focuses particularly on (1) one-dimensional (1)H MRS, (2) two-dimensional (1)H MRS, and (3) one-dimensional (13)C MRS techniques.
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Affiliation(s)
- Saadallah Ramadan
- School of Health Sciences, Faculty of Health, Hunter Building, University of Newcastle, Callaghan NSW 2308, Australia
| | - Alexander Lin
- Alexander Lin: Center for Clinical Spectroscopy, Department of Radiology, Brigham and Women’s Hospital, Harvard Medical School, 4 Blackfan Street, HIM-820, Boston MA 02115
| | - Peter Stanwell
- School of Health Sciences, Faculty of Health, Hunter Building, University of Newcastle, Callaghan NSW 2308, Australia
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Yahya A, De Zanche N, Allen PS. A dual-tuned transceive resonator for (13) C{(1) H} MRS: two open coils in one. NMR IN BIOMEDICINE 2013; 26:533-541. [PMID: 23401299 DOI: 10.1002/nbm.2890] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Revised: 10/01/2012] [Accepted: 10/18/2012] [Indexed: 06/01/2023]
Abstract
Proton-decoupled, (13) C nuclear MRS experiments require a RF coil that operates at the Larmor frequencies of both (13) C and (1) H. In this work, we designed, built and tested a single-unit, dual-tuned coil based on a half-birdcage open coil design. It was constructed as a low-pass network with a resonant trap in series with each leg. Traps are tuned in alternate legs such that the two resonant modes arise from currents on alternate legs. The coil performance was compared with that of a dual-tuned coil consisting of two proton surface coils operating in quadrature and a single surface coil for (13) C transmission and reception. The half-birdcage coil was shown to produce a more homogeneous RF field at each frequency and was more sensitive to a (13) C signal arising from regions further from the coil surface. The applicability of the coil in vivo was demonstrated by acquiring a proton decoupled, natural abundance (13) C glycogen signal from the calf of a normal volunteer.
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Affiliation(s)
- Atiyah Yahya
- Department of Medical Physics, Cross Cancer Institute, Edmonton, Alberta, Canada.
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39
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Shen J. Modeling the glutamate-glutamine neurotransmitter cycle. FRONTIERS IN NEUROENERGETICS 2013; 5:1. [PMID: 23372548 PMCID: PMC3556573 DOI: 10.3389/fnene.2013.00001] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Accepted: 01/08/2013] [Indexed: 02/05/2023]
Abstract
Glutamate is the principal excitatory neurotransmitter in brain. Although it is rapidly synthesized from glucose in neural tissues the biochemical processes for replenishing the neurotransmitter glutamate after glutamate release involve the glutamate–glutamine cycle. Numerous in vivo13C magnetic resonance spectroscopy (MRS) experiments since 1994 by different laboratories have consistently concluded: (1) the glutamate–glutamine cycle is a major metabolic pathway with a flux rate substantially greater than those suggested by early studies of cell cultures and brain slices; (2) the glutamate–glutamine cycle is coupled to a large portion of the total energy demand of brain function. The dual roles of glutamate as the principal neurotransmitter in the CNS and as a key metabolite linking carbon and nitrogen metabolism make it possible to probe glutamate neurotransmitter cycling using MRS by measuring the labeling kinetics of glutamate and glutamine. At the same time, comparing to non-amino acid neurotransmitters, the added complexity makes it more challenging to quantitatively separate neurotransmission events from metabolism. Over the past few years our understanding of the neuronal-astroglial two-compartment metabolic model of the glutamate–glutamine cycle has been greatly advanced. In particular, the importance of isotopic dilution of glutamine in determining the glutamate–glutamine cycling rate using [1−13C] or [1,6-13C2] glucose has been demonstrated and reproduced by different laboratories. In this article, recent developments in the two-compartment modeling of the glutamate–glutamine cycle are reviewed. In particular, the effects of isotopic dilution of glutamine on various labeling strategies for determining the glutamate–glutamine cycling rate are analyzed. Experimental strategies for measuring the glutamate–glutamine cycling flux that are insensitive to isotopic dilution of glutamine are also suggested.
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Affiliation(s)
- Jun Shen
- Molecular Imaging Branch, National Institute of Mental Health Bethesda, MD, USA
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Mishkovsky M, Comment A, Gruetter R. In vivo detection of brain Krebs cycle intermediate by hyperpolarized magnetic resonance. J Cereb Blood Flow Metab 2012; 32:2108-13. [PMID: 22990416 PMCID: PMC3519415 DOI: 10.1038/jcbfm.2012.136] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The Krebs (or tricarboxylic acid (TCA)) cycle has a central role in the regulation of brain energy regulation and metabolism, yet brain TCA cycle intermediates have never been directly detected in vivo. This study reports the first direct in vivo observation of a TCA cycle intermediate in intact brain, namely, 2-oxoglutarate, a key biomolecule connecting metabolism to neuronal activity. Our observation reveals important information about in vivo biochemical processes hitherto considered undetectable. In particular, it provides direct evidence that transport across the inner mitochondria membrane is rate limiting in the brain. The hyperpolarized magnetic resonance protocol designed for this study opens the way to direct and real-time studies of TCA cycle kinetics.
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Affiliation(s)
- Mor Mishkovsky
- Laboratory for Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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41
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McKenna MC. Substrate competition studies demonstrate oxidative metabolism of glucose, glutamate, glutamine, lactate and 3-hydroxybutyrate in cortical astrocytes from rat brain. Neurochem Res 2012; 37:2613-26. [PMID: 23079895 DOI: 10.1007/s11064-012-0901-3] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Revised: 10/01/2012] [Accepted: 10/03/2012] [Indexed: 01/14/2023]
Abstract
It is well established that astrocytes can utilize many substrates to support oxidative energy metabolism; however, use of energy substrates in the presence of other substrates, as would occur in vivo, has not been systematically evaluated. Substrate competition studies were used to determine changes in the rates of (14)CO(2) production since little is known about the interaction of energy substrates in astrocytes. The rates of (14)CO(2) production from 1 mM D-[6-(14)C]glucose, L-[U-(14)C]glutamate, L-[U-(14)C]glutamine, D-3-hydroxy[3-(14)C]butyrate, L-[U-(14)C]lactate and L-[U-(14)C]malate by primary cultures of astrocytes from rat brain were determined to be 1.17 ± 0.19, 85.30 ± 12.25, 28.04 ± 2.84, 13.55 ± 4.56, 14.84 ± 2.40 and 5.20 ± 1.20 nmol/h/mg protein (mean ± SEM), respectively. The rate of (14)CO(2) production from glutamate oxidation was higher than that of the other substrates Addition of unlabeled glutamate significantly decreased the rates of (14)CO(2) production from all other substrates studied; however, glutamate oxidation was not altered by the addition of any of the other substrates. The rate of (14)CO(2) production of glutamine was decreased by glutamate, but not altered by other substrates. The rate of (14)CO(2) production from glucose was significantly decreased by the addition of unlabeled glutamate, glutamine or lactate, but not by 3-hydroxybutyrate or malate. Addition of unlabeled glucose did not significantly alter the (14)CO(2) production from any other substrate. (14)CO(2) production from lactate was decreased by the addition of unlabeled glutamine or glutamate and increased by addition of malate. The (14)CO(2) production from malate was decreased by the addition of unlabeled glutamate or lactate, but was not altered by the other substrates. The substrate utilization for oxidative energy metabolism in astrocytes is very different than the profile previously reported for synaptic terminals. These studies demonstrate the potential use of multiple substrates including glucose, glutamate, glutamine, lactate and 3-hydroxybutyrate as energy substrates for astrocytes. The data also provide evidence of interactions of substrates and multiple compartments of TCA cycle activity in cultured astrocytes.
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Affiliation(s)
- Mary C McKenna
- Department of Pediatrics and Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, USA.
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42
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Li B, Hertz L, Peng L. Aralar mRNA and protein levels in neurons and astrocytes freshly isolated from young and adult mouse brain and in maturing cultured astrocytes. Neurochem Int 2012; 61:1325-32. [PMID: 23017600 DOI: 10.1016/j.neuint.2012.09.009] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Revised: 09/04/2012] [Accepted: 09/13/2012] [Indexed: 10/27/2022]
Abstract
Intense glucose-based energy metabolism and glutamate synthesis by astrocytes require malate-aspartate-shuttle (MAS) activity to regenerate NAD⁺ from NADH formed during glycolysis, since brain lacks significant glycerophosphate shuttle activity. Aralar is a necessary aspartate/glutamate exchanger for MAS function in brain. Based on cytochemical immunoassays the absence of aralar in adult astrocytes was repeatedly reported. This would mean that adult astrocytes must regenerate NAD⁺ by producing lactate from pyruvate, eliminating its use by oxidative and biosynthetic pathways. We alternatively used astrocytes and neurons from adult brain, freshly isolated by fluorescence-activated cell sorting, to determine aralar protein by a specific antibody and its mRNA by real-time PCR. Both protein and mRNA expressions were identical in adult neurons and astrocytes and similar to whole brain levels. The same level of aralar expression was reached in well-differentiated astrocyte cultures, but not until late development, coinciding with the late-maturing brain capability for glutamate formation and degradation.
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Affiliation(s)
- Baoman Li
- Department of Clinical Pharmacology, China Medical University, Shenyang, PR China
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43
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Volkow ND, Kim SW, Wang GJ, Alexoff D, Logan J, Muench L, Shea C, Telang F, Fowler JS, Wong C, Benveniste H, Tomasi D. Acute alcohol intoxication decreases glucose metabolism but increases acetate uptake in the human brain. Neuroimage 2012; 64:277-83. [PMID: 22947541 DOI: 10.1016/j.neuroimage.2012.08.057] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Revised: 08/09/2012] [Accepted: 08/21/2012] [Indexed: 10/28/2022] Open
Abstract
Alcohol intoxication results in marked reductions in brain glucose metabolism, which we hypothesized reflect not just its GABAergic enhancing effects but also the metabolism of acetate as an alternative brain energy source. To test this hypothesis we separately assessed the effects of alcohol intoxication on brain glucose and acetate metabolism using Positron Emission Tomography (PET). We found that alcohol intoxication significantly decreased whole brain glucose metabolism (measured with FDG) with the largest decrements in cerebellum and occipital cortex and the smallest in the thalamus. In contrast, alcohol intoxication caused a significant increase in [1-(11)C]acetate brain uptake (measured as standard uptake value, SUV), with the largest increases occurring in the cerebellum and the smallest in the thalamus. In heavy alcohol drinkers [1-(11)C]acetate brain uptake during alcohol challenge tended to be higher than in occasional drinkers (p<0.06) and the increases in [1-(11)C]acetate uptake in cerebellum with alcohol were positively associated with the reported amount of alcohol consumed (r=0.66, p<0.01). Our findings corroborate a reduction of brain glucose metabolism during intoxication and document an increase in brain acetate uptake. The opposite changes observed between regional brain metabolic decrements and regional increases in [1-(11)C]acetate uptake support the hypothesis that during alcohol intoxication the brain may rely on acetate as an alternative brain energy source and provides preliminary evidence that heavy alcohol exposures may facilitate the use of acetate as an energy substrate. These findings raise the question of the potential therapeutic benefits that increasing plasma acetate concentration (i.e. ketogenic diets) may have in alcoholics undergoing alcohol detoxification.
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Affiliation(s)
- Nora D Volkow
- National Institute on Drug Abuse, Bethesda, MD 20892, USA.
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44
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Quantitative fMRI and oxidative neuroenergetics. Neuroimage 2012; 62:985-94. [PMID: 22542993 DOI: 10.1016/j.neuroimage.2012.04.027] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Revised: 04/09/2012] [Accepted: 04/10/2012] [Indexed: 11/22/2022] Open
Abstract
The discovery of functional magnetic resonance imaging (fMRI) has greatly impacted neuroscience. The blood oxygenation level-dependent (BOLD) signal, using deoxyhemoglobin as an endogenous paramagnetic contrast agent, exposes regions of interest in task-based and resting-state paradigms. However the BOLD contrast is at best a partial measure of neuronal activity, because the functional maps obtained by differencing or correlations ignore the total neuronal activity in the baseline state. Here we describe how studies of brain energy metabolism at Yale, especially with (13)C magnetic resonance spectroscopy and related techniques, contributed to development of quantitative functional brain imaging with fMRI by providing a reliable measurement of baseline energy. This narrative takes us on a journey, from molecules to mind, with illuminating insights about neuronal-glial activities in relation to energy demand of synaptic activity. These results, along with key contributions from laboratories worldwide, comprise the energetic basis for quantitative interpretation of fMRI data.
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45
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Schousboe A. Studies of Brain Metabolism: A Historical Perspective. NEURAL METABOLISM IN VIVO 2012. [DOI: 10.1007/978-1-4614-1788-0_31] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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46
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Rothman DL, De Feyter HM, de Graaf RA, Mason GF, Behar KL. 13C MRS studies of neuroenergetics and neurotransmitter cycling in humans. NMR IN BIOMEDICINE 2011; 24:943-57. [PMID: 21882281 PMCID: PMC3651027 DOI: 10.1002/nbm.1772] [Citation(s) in RCA: 187] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Revised: 06/09/2011] [Accepted: 06/14/2011] [Indexed: 05/05/2023]
Abstract
In the last 25 years, (13)C MRS has been established as the only noninvasive method for the measurement of 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 energy cost of brain function, the high neuronal activity in the resting brain state and how neuroenergetics and neurotransmitter cycling are altered in neurological and psychiatric disease. In this article, the current state of (13)C MRS as it is applied to the study of neuroenergetics and neurotransmitter cycling in humans is reviewed. The focus is predominantly on recent findings in humans regarding metabolic pathways, applications to clinical research and the technical status of the method. Results from in vivo (13)C MRS studies in animals are discussed from the standpoint of the validation of MRS measurements of neuroenergetics and neurotransmitter cycling, and where they have helped to identify key questions to address in human research. Controversies concerning the relationship between neuroenergetics and neurotransmitter cycling and factors having an impact on the accurate determination of fluxes through mathematical modeling are addressed. We further touch upon different (13)C-labeled substrates used to study brain metabolism, before reviewing a number of human brain diseases investigated using (13)C MRS. Future technological developments are discussed that will help to overcome the limitations of (13)C MRS, with special attention given to recent developments in hyperpolarized (13)C MRS.
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Affiliation(s)
- Douglas L Rothman
- Department of Diagnostic Radiology, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, CT 06520-8043, USA.
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Hertz L. Astrocytic energy metabolism and glutamate formation--relevance for 13C-NMR spectroscopy and importance of cytosolic/mitochondrial trafficking. Magn Reson Imaging 2011; 29:1319-29. [PMID: 21820830 DOI: 10.1016/j.mri.2011.04.013] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2011] [Revised: 04/21/2011] [Accepted: 04/22/2011] [Indexed: 11/18/2022]
Abstract
Glutamate plays a double role in (13)C-nuclear magnetic resonance (NMR) spectroscopic determination of glucose metabolism in the brain. Bidirectional exchange between initially unlabeled glutamate and labeled α-ketoglutarate, formed from pyruvate via pyruvate dehydrogenase (PDH), indicates the rate of energy metabolism in the tricarboxylic acid (V(TCA)) cycle in neurons (V(PDH, n)) and, with additional computation, also in astrocytes (V(PDH, g)), as confirmed using the astrocyte-specific substrate [(13)C]acetate. Formation of new molecules of glutamate during increased glutamatergic activity occurs only in astrocytes by combined pyruvate carboxylase (V(PC)) and astrocytic PDH activity. V(PDH, g) accounts for ~15% of total pyruvate metabolism in the brain cortex, and V(PC) accounts for another ~10%. Since both PDH-generated and PC-generated pyruvates are needed for glutamate synthesis, ~20/25 (80%) of astrocytic pyruvate metabolism proceed via glutamate formation. Net transmitter glutamate [γ-aminobutyric acid (GABA)] formation requires transfer of newly synthesized α-ketoglutarate to the astrocytic cytosol, α-ketoglutarate transamination to glutamate, amidation to glutamine, glutamine transfer to neurons, its hydrolysis to glutamate and glutamate release (or GABA formation). Glutamate-glutamine cycling, measured as glutamine synthesis rate (V(cycle)), also transfers previously released glutamate/GABA to neurons after an initial astrocytic accumulation and measures predominantly glutamate signaling. An empirically established ~1/1 ratio between glucose metabolism and V(cycle) may reflect glucose utilization associated with oxidation/reduction processes during glutamate production, which together with associated transamination processes are balanced by subsequent glutamate oxidation after cessation of increased signaling activity. Astrocytic glutamate formation and subsequent oxidative metabolism provide large amounts of adenosine triphosphate used for accumulation from extracellular clefts of neuronally released K(+) and glutamate and for cytosolic Ca(2+) homeostasis.
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Affiliation(s)
- Leif Hertz
- Department of Clinical Pharmacology, College of Basic Medical Sciences, China Medical University, No. 92 Beier Road, Heping District, Shenyang, PR China.
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48
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Xiang Y, Shen J. Simultaneous detection of cerebral metabolism of different substrates by in vivo ¹³C isotopomer MRS. J Neurosci Methods 2011; 198:8-15. [PMID: 21419161 DOI: 10.1016/j.jneumeth.2011.02.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Revised: 02/18/2011] [Accepted: 02/18/2011] [Indexed: 10/18/2022]
Abstract
In this report a new method is introduced for simultaneous detection of the metabolism of two ¹³C-labeled subtracts in brain in vivo. We recognized and experimentally demonstrated that when a ¹³C-labeled substrate generates [1,2-¹³C₂]acetylCoA ([1-¹³C]acetylCoA) only, glutamate C5, glutamine C5 and apsartate C4 doublets (singlets) are formed exclusively, regardless of the number of turns of the tricarboxylic acid cycle. We utilized the large one-bond ¹³C-¹³C homonuclear J coupling between a carboxylic/amide carbon and an aliphatic carbon (~50 Hz) and demonstrated that it is feasible to simultaneously detect the labeling of brain metabolites by two different substrates using different isotopomer signals of the same carbon atom. Uniformly labeled glucose was used to generate the doublets and a second substrate ([2-¹³C] lactate or [1,3-¹³C₂]β-hydroxybutyrate or [1-¹³C] acetate) was used to generate the singlets. It was shown that contribution to cerebral metabolism from different substrates can be simultaneously measured in vivo.
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Affiliation(s)
- Yun Xiang
- Molecular Imaging Branch, National Institute of Mental Health Intramural Research Program, National Institutes of Health, Bldg. 10, Rm. 2D51A, 9000 Rockville Pike, Bethesda, MD 20892-1527, USA
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49
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Xin L, Mlynárik V, Lanz B, Frenkel H, Gruetter R. 1H-[13C] NMR spectroscopy of the rat brain during infusion of [2-13C] acetate at 14.1 T. Magn Reson Med 2011; 64:334-40. [PMID: 20535808 DOI: 10.1002/mrm.22359] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Full signal intensity (1)H-[(13)C] NMR spectroscopy, combining a preceding (13)C-editing block based on an inversion BISEP (B(1)-insensitive spectral editing pulse) with a spin-echo coherence-based localization, was developed and implemented at 14.1 T. (13)C editing of the proposed scheme was achieved by turning on and off the (13)C adiabatic full passage in the (13)C-editing block to prepare inverted and noninverted (13)C-coupled (1)H coherences along the longitudinal axis prior to localization. The novel (1)H-[(13)C] NMR approach was applied in vivo under infusion of the glia-specific substrate [2-(13)C] acetate. Besides a approximately 50% improvement in sensitivity, spectral dispersion was enhanced at 14.1 T, especially for J-coupled metabolites such as glutamate and glutamine. A more distinct spectral structure at 1.9-2.2 ppm(parts per million) was observed, e.g., glutamate C3 showed a doublet pattern in both simulated (1)H spectrum and in vivo (13)C-edited (1)H NMR spectra. Besides (13)C time courses of glutamate C4 and glutamine C4, the time courses of glutamate C3 and glutamine C3 obtained by (1)H-[(13)C] NMR spectroscopy were reported for the first time. Such capability should greatly improve the ability to study neuron-glial metabolism using (1)H-observed (13)C-edited NMR spectroscopy.
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Affiliation(s)
- Lijing Xin
- Laboratory of Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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Sailasuta N, Harris K, Tran T, Ross B. Minimally invasive biomarker confirms glial activation present in Alzheimer's disease: a preliminary study. Neuropsychiatr Dis Treat 2011; 7:495-9. [PMID: 21931491 PMCID: PMC3173032 DOI: 10.2147/ndt.s23721] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
We applied (13)C magnetic resonance spectroscopy (MRS), a nonradioactive, noninvasive brain imaging technique, to quantify the oxidation of [1-(13)C] acetate in a conventional clinical magnetic resonance imaging (MRI) scanner in five consecutive elderly subjects at various clinical stages of Alzheimer's disease (AD) progression. [1-(13)C] acetate entered the brain and was metabolized to [5-(13)C] glutamate and glutamine, as well as [1-(13)C] glutamate and glutamine, and the final glial oxidation product, (13)C bicarbonate, at a linear rate. Calculation of the initial slope was similar in a single subject, examined twice, 1 month apart (test-re-test 8%). Mean rate of cerebral bicarbonate production in this elderly group was 0.040 ± 0.01 (n = 5). Assuming that the rate of conversion of acetate to bicarbonate is a reflection of glial metabolic rate and that glial metabolic rate is a surrogate marker for 'neuroinflammation', our preliminary results suggest that [1-(13)C] MRS may provide biomarkers for diseases, believed to involve microglia and other cells of the astrocyte series. Among these is AD, for which novel drugs which ameliorate the damaging effects of neuroinflammation before symptoms of dementia appear, are in advanced development. The value of (13)C MRS as an early, noninvasive biomarker may lie in the conduct of cost-effective clinical trials.
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Affiliation(s)
- Napapon Sailasuta
- Clinical MR Unit, Huntington Medical Research Institutes, Pasadena, CA, USA
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