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Ziegs T, Ruhm L, Wright A, Henning A. Mapping of glutamate metabolism using 1H FID-MRSI after oral administration of [1-13C]Glc at 9.4 T. Neuroimage 2023; 270:119940. [PMID: 36787828 PMCID: PMC10030312 DOI: 10.1016/j.neuroimage.2023.119940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 02/10/2023] [Accepted: 02/11/2023] [Indexed: 02/14/2023] Open
Abstract
Glutamate is the major excitatory transmitter in the brain and malfunction of the related metabolism is associated with various neurological diseases and disorders. The observation of labeling changes in the spectra after the administration of a 13C labelled tracer is a common tool to gain better insights into the function of the metabolic system. But so far, only a very few studies presenting the labeling effects in more than two voxels to show the spatial dependence of metabolism. In the present work, the labeling effects were measured in a transversal plane in the human brain using ultra-short TE and TR 1H FID-MRSI. The measurement set-up was most simple: The [1-13C]Glc was administered orally instead of intravenous and the spectra were measured with a pure 1H technique without the need of a 13C channel (as Boumezbeur et al. demonstrated in 2004). Thus, metabolic maps and enrichment curves could be obtained for more metabolites and in more voxels than ever before in human brain. Labeling changes could be observed in [4-13C]glutamate, [3-13C]glutamate+glutamine, [2-13C]glutamate+glutamine, [4-13C]glutamine, and [3-13C]aspartate with a high temporal (3.6 min) and spatial resolution (32 × 32 grid with nominal voxel size of 0.33 µL) in five volunteers.
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Affiliation(s)
- Theresia Ziegs
- High-Field MR Center, Max Planck Institute for Biological Cybernetics, Max-Planck-Ring 11, 72076 Tübingen, Germany; IMPRS for Cognitive and Systems Neuroscience, Otfried-Müller-Str. 27, 72076 Tübingen, Germany.
| | - Loreen Ruhm
- High-Field MR Center, Max Planck Institute for Biological Cybernetics, Max-Planck-Ring 11, 72076 Tübingen, Germany; IMPRS for Cognitive and Systems Neuroscience, Otfried-Müller-Str. 27, 72076 Tübingen, Germany
| | - Andrew Wright
- High-Field MR Center, Max Planck Institute for Biological Cybernetics, Max-Planck-Ring 11, 72076 Tübingen, Germany; IMPRS for Cognitive and Systems Neuroscience, Otfried-Müller-Str. 27, 72076 Tübingen, Germany
| | - Anke Henning
- High-Field MR Center, Max Planck Institute for Biological Cybernetics, Max-Planck-Ring 11, 72076 Tübingen, Germany; Advanced Imaging Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390, United States
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2
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Ziegs T, Dorst J, Ruhm L, Avdievitch N, Henning A. Measurement of glucose metabolism in the occipital lobe and frontal cortex after oral administration of [1-13C]glucose at 9.4 T. J Cereb Blood Flow Metab 2022; 42:1890-1904. [PMID: 35632989 PMCID: PMC9536126 DOI: 10.1177/0271678x221104540] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
For the first time, labeling effects after oral intake of [1-13C]glucose are observed in the human brain with pure 1H detection at 9.4 T. Spectral time series were acquired using a short-TE 1H MRS MC-semiLASER (Metabolite Cycling semi Localization by Adiabatic SElective Refocusing) sequence in two voxels of 5.4 mL in the frontal cortex and the occipital lobe. High-quality time-courses of [4-13C]glutamate, [4-13C]glutamine, [3-13C]glutamate + glutamine, [2-13C] glutamate+glutamine and [3-13C]aspartate for individual volunteers and additionally, group-averaged time-courses of labeled and non-labeled brain glucose could be obtained. Using a one-compartment model, mean metabolic rates were calculated for each voxel position: The mean rate of the TCA-cycle (Vtca) value was determined to be 1.36 and 0.93 μmol min-1 g-1, the mean rate of glutamine synthesis (Vgln) was calculated to be 0.23 and 0.45 μmol min-1 g-1, the mean exchange rate between cytosolic amino acids and mitochondrial Krebs cycle intermediates (Vx) rate was found to be 0.57 and 1.21 μmol min-1 g-1 for the occipital lobe and the frontal cortex, respectively. These values were in agreement with previously reported data. Altogether, it can be shown that this most simple technique combining oral administration of [1-13C]Glc with pure 1H MRS acquisition is suitable to measure metabolic rates.
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Affiliation(s)
- Theresia Ziegs
- High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.,IMPRS for Cognitive and Systems Neuroscience, Tübingen, Germany
| | - Johanna Dorst
- High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.,IMPRS for Cognitive and Systems Neuroscience, Tübingen, Germany
| | - Loreen Ruhm
- High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.,IMPRS for Cognitive and Systems Neuroscience, Tübingen, Germany
| | - Nikolai Avdievitch
- High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | - Anke Henning
- High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.,Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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3
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Cacciatore M, Grasso EA, Tripodi R, Chiarelli F. Impact of glucose metabolism on the developing brain. Front Endocrinol (Lausanne) 2022; 13:1047545. [PMID: 36619556 PMCID: PMC9816389 DOI: 10.3389/fendo.2022.1047545] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Accepted: 12/13/2022] [Indexed: 12/24/2022] Open
Abstract
Glucose is the most important substrate for proper brain functioning and development, with an increased glucose consumption in relation to the need of creating new brain structures and connections. Therefore, alterations in glucose homeostasis will inevitably be associated with changes in the development of the Nervous System. Several studies demonstrated how the alteration of glucose homeostasis - both hyper and hypoglycemia- may interfere with the development of brain structures and cognitivity, including deficits in intelligence quotient, anomalies in learning and memory, as well as differences in the executive functions. Importantly, differences in brain structure and functionality were found after a single episode of diabetic ketoacidosis suggesting the importance of glycemic control and stressing the need of screening programs for type 1 diabetes to protect children from this dramatic condition. The exciting progresses of the neuroimaging techniques such as diffusion tensor imaging, has helped to improve the understanding of the effects, outcomes and mechanisms underlying brain changes following dysglycemia, and will lead to more insights on the physio-pathological mechanisms and related neurological consequences about hyper and hypoglycemia.
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4
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Whitehead MT, Bluml S. Proton and Multinuclear Spectroscopy of the Pediatric Brain. Magn Reson Imaging Clin N Am 2021; 29:543-555. [PMID: 34717844 DOI: 10.1016/j.mric.2021.06.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Magnetic resonance spectroscopy (MRS) is a valuable adjunct to structural brain imaging. State-of-the-art MRS has benefited greatly from recent technical advancements. Neurometabolic alterations in pediatric brain diseases have implications for diagnosis, prognosis, and therapy. Herein, the authors discuss MRS technical considerations and applications in the setting of various pediatric disease processes including tumors, metabolic diseases, hypoxic/ischemic encephalopathy/stroke, epilepsy, demyelinating disease, and infection.
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Affiliation(s)
- Matthew T Whitehead
- Department of Radiology, Children's National Hospital, 111 Michigan Avenue NW, Washington, DC 20010, USA; Prenatal Pediatrics Institute, Children's National Hospital, Washington, DC, USA; The George Washington University School of Medicine and Health Sciences, Washington, DC, USA.
| | - Stefan Bluml
- Department of Radiology, Children's Hospital Los Angeles, Keck School of Medicine, University of Southern California, 450 Sunset Boulevard, Los Angeles, CA 90027, USA; Rudi Schulte Research Institute, Santa Barbara, CA, USA
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5
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Zhu XH, Lee BY, Tuite P, Coles L, Sathe AG, Chen C, Cloyd J, Low WC, Steer CJ, Chen W. Quantitative Assessment of Occipital Metabolic and Energetic Changes in Parkinson's Patients, Using In Vivo 31P MRS-Based Metabolic Imaging at 7T. Metabolites 2021; 11:metabo11030145. [PMID: 33804401 PMCID: PMC8000945 DOI: 10.3390/metabo11030145] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 02/22/2021] [Accepted: 02/24/2021] [Indexed: 12/14/2022] Open
Abstract
Abnormal energy metabolism associated with mitochondrial dysfunction is thought to be a major contributor to the progression of neurodegenerative diseases such as Parkinson's disease (PD). Recent advancements in the field of magnetic resonance (MR) based metabolic imaging provide state-of-the-art technologies for non-invasively probing cerebral energy metabolism under various brain conditions. In this proof-of-principle clinical study, we employed quantitative 31P MR spectroscopy (MRS) imaging techniques to determine a constellation of metabolic and bioenergetic parameters, including cerebral adenosine triphosphate (ATP) and other phosphorous metabolite concentrations, intracellular pH and nicotinamide adenine dinucleotide (NAD) redox ratio, and ATP production rates in the occipital lobe of cognitive-normal PD patients, and then we compared them with age-sex matched healthy controls. Small but statistically significant differences in intracellular pH, NAD and ATP contents and ATPase enzyme activity between the two groups were detected, suggesting that subtle defects in energy metabolism and mitochondrial function are quantifiable before regional neurological deficits or pathogenesis begin to occur in these patients. Pilot data aiming to evaluate the bioenergetic effect of mitochondrial-protective bile acid, ursodeoxycholic acid (UDCA) were also obtained. These results collectively demonstrated that in vivo 31P MRS-based neuroimaging can non-invasively and quantitatively assess key metabolic-energetic metrics in the human brain. This provides an exciting opportunity to better understand neurodegenerative diseases, their progression and response to treatment.
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Affiliation(s)
- Xiao-Hong Zhu
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN 55455, USA;
- Correspondence: (X.-H.Z.); (W.C.); Tel.: +1-(612) 626-2001 (X.-H.Z.); Fax: +1-(612) 626-2004 (X.-H.Z.)
| | - Byeong-Yeul Lee
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN 55455, USA;
| | - Paul Tuite
- Department of Neurology, University of Minnesota, Minneapolis, MN 55455, USA;
| | - Lisa Coles
- Department of Experimental and Clinical Pharmacology, University of Minnesota, Minneapolis, MN 55455, USA; (L.C.); (A.G.S.); (J.C.)
| | - Abhishek G. Sathe
- Department of Experimental and Clinical Pharmacology, University of Minnesota, Minneapolis, MN 55455, USA; (L.C.); (A.G.S.); (J.C.)
| | - Chi Chen
- Department of Food Science and Nutrition, University of Minnesota, Minneapolis, MN 55455, USA;
| | - Jim Cloyd
- Department of Experimental and Clinical Pharmacology, University of Minnesota, Minneapolis, MN 55455, USA; (L.C.); (A.G.S.); (J.C.)
| | - Walter C. Low
- Department of Neurosurgery, University of Minnesota, Minneapolis, MN 55455, USA;
| | - Clifford J. Steer
- Departments of Medicine and Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455, USA;
| | - Wei Chen
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN 55455, USA;
- Correspondence: (X.-H.Z.); (W.C.); Tel.: +1-(612) 626-2001 (X.-H.Z.); Fax: +1-(612) 626-2004 (X.-H.Z.)
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6
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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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7
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Weinstock NI, Wrabetz L, Feltri ML, Shin D. Metabolic profiling reveals biochemical pathways and potential biomarkers associated with the pathogenesis of Krabbe disease. J Neurosci Res 2017; 94:1094-107. [PMID: 27638595 DOI: 10.1002/jnr.23789] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 05/06/2016] [Accepted: 05/20/2016] [Indexed: 01/09/2023]
Abstract
Krabbe disease (KD) is caused by mutations in the galactosylceramidase (GALC) gene, which encodes a lysosomal enzyme that degrades galactolipids, including galactosylceramide and galactosylsphingosine (psychosine). GALC deficiency results in progressive intracellular accumulation of psychosine, which is believed to be the main cause for the demyelinating neurodegeneration in KD pathology. Umbilical cord blood transplantation slows disease progression when performed presymptomatically but carries a significant risk of morbidity and mortality. Accurate presymptomatic diagnosis is therefore critical to facilitate the efficacy of existing transplant approaches and to avoid unnecessary treatment of children who will not develop KD. Unfortunately, current diagnostic criteria, including GALC activity, genetic analysis, and psychosine measurement, are insufficient for secure presymptomatic diagnosis. This study performs a global metabolomic analysis to identify pathogenetic metabolic pathways and novel biomarkers implicated in the authentic mouse model of KD known as twitcher. At a time point before onset of signs of disease, twitcher hindbrains had metabolic profiles similar to WT, with the exception of a decrease in metabolites related to glucose energy metabolism. Many metabolic pathways were altered after early signs of disease in the twitcher, including decreased phospholipid turnover, restricted mitochondrial metabolism of branched-chain amino acids, increased inflammation, and changes in neurotransmitter metabolism and osmolytes. Hypoxanthine, a purine derivative, is increased before signs of disease appear, suggesting its potential as a biomarker for early diagnosis of KD. Additionally, given the early changes in glucose metabolism in the pathogenesis of KD, diagnostic modalities that report metabolic function, such as positron emission tomography, may be useful in KD. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Nadav I Weinstock
- Hunter James Kelly Research Institute, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York.,Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York
| | - Lawrence Wrabetz
- Hunter James Kelly Research Institute, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York.,Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York.,Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York
| | - M Laura Feltri
- Hunter James Kelly Research Institute, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York.,Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York.,Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York
| | - Daesung Shin
- Hunter James Kelly Research Institute, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York. .,Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York.
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8
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Ghosh N, Holshouser B, Oyoyo U, Barnes S, Tong K, Ashwal S. Combined Diffusion Tensor and Magnetic Resonance Spectroscopic Imaging Methodology for Automated Regional Brain Analysis: Application in a Normal Pediatric Population. Dev Neurosci 2017. [PMID: 28651252 DOI: 10.1159/000475545] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
During human brain development, anatomic regions mature at different rates. Quantitative anatomy-specific analysis of longitudinal diffusion tensor imaging (DTI) and magnetic resonance spectroscopic imaging (MRSI) data may improve our ability to quantify and categorize these maturational changes. Computational tools designed to quickly fuse and analyze imaging information from multiple, technically different datasets would facilitate research on changes during normal brain maturation and for comparison to disease states. In the current study, we developed a complete battery of computational tools to execute such data analyses that include data preprocessing, tract-based statistical analysis from DTI data, automated brain anatomy parsing from T1-weighted MR images, assignment of metabolite information from MRSI data, and co-alignment of these multimodality data streams for reporting of region-specific indices. We present statistical analyses of regional DTI and MRSI data in a cohort of normal pediatric subjects (n = 72; age range: 5-18 years; mean 12.7 ± 3.3 years) to establish normative data and evaluate maturational trends. Several regions showed significant maturational changes for several DTI parameters and MRSI ratios, but the percent change over the age range tended to be small. In the subcortical region (combined basal ganglia [BG], thalami [TH], and corpus callosum [CC]), the largest combined percent change was a 10% increase in fractional anisotropy (FA) primarily due to increases in the BG (12.7%) and TH (9%). The largest significant percent increase in N-acetylaspartate (NAA)/creatine (Cr) ratio was seen in the brain stem (BS) (18.8%) followed by the subcortical regions in the BG (11.9%), CC (8.9%), and TH (6.0%). We found consistent, significant (p < 0.01), but weakly positive correlations (r = 0.228-0.329) between NAA/Cr ratios and mean FA in the BS, BG, and CC regions. Age- and region-specific normative MR diffusion and spectroscopic metabolite ranges show brain maturation changes and are requisite for detecting abnormalities in an injured or diseased population.
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Affiliation(s)
- Nirmalya Ghosh
- Department of Pediatrics, Loma Linda University School of Medicine, Loma Linda, CA, USA
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9
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Patel AB, Lai JCK, Chowdhury GIM, Rothman DL, Behar KL. Comparison of Glutamate Turnover in Nerve Terminals and Brain Tissue During [1,6- 13C 2]Glucose Metabolism in Anesthetized Rats. Neurochem Res 2016; 42:173-190. [PMID: 28025798 DOI: 10.1007/s11064-016-2103-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 11/06/2016] [Accepted: 11/08/2016] [Indexed: 01/05/2023]
Abstract
The 13C turnover of neurotransmitter amino acids (glutamate, GABA and aspartate) were determined from extracts of forebrain nerve terminals and brain homogenate, and fronto-parietal cortex from anesthetized rats undergoing timed infusions of [1,6-13C2]glucose or [2-13C]acetate. Nerve terminal 13C fractional labeling of glutamate and aspartate was lower than those in whole cortical tissue at all times measured (up to 120 min), suggesting either the presence of a constant dilution flux from an unlabeled substrate or an unlabeled (effectively non-communicating on the measurement timescale) glutamate pool in the nerve terminals. Half times of 13C labeling from [1,6-13C2]glucose, as estimated by least squares exponential fitting to the time course data, were longer for nerve terminals (GluC4, 21.8 min; GABAC2 21.0 min) compared to cortical tissue (GluC4, 12.4 min; GABAC2, 14.5 min), except for AspC3, which was similar (26.5 vs. 27.0 min). The slower turnover of glutamate in the nerve terminals (but not GABA) compared to the cortex may reflect selective effects of anesthesia on activity-dependent glucose use, which might be more pronounced in the terminals. The 13C labeling ratio for glutamate-C4 from [2-13C]acetate over that of 13C-glucose was twice as large in nerve terminals compared to cortex, suggesting that astroglial glutamine under the 13C glucose infusion was the likely source of much of the nerve terminal dilution. The net replenishment of most of the nerve terminal amino acid pools occurs directly via trafficking of astroglial glutamine.
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Affiliation(s)
- Anant B Patel
- Department of Diagnostic Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, CT, 06520, USA. .,CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, 500007, India.
| | - James C K Lai
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, Idaho State University, Pocatello, ID, 83209, USA
| | - Golam I M Chowdhury
- Department of Psychiatry, Magnetic Resonance Research Center, Yale University School of Medicine, 300 Cedar Street, PO Box 208043, New Haven, CT, 06520, USA
| | - Douglas L Rothman
- Department of Diagnostic Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, CT, 06520, USA
| | - Kevin L Behar
- Department of Psychiatry, Magnetic Resonance Research Center, Yale University School of Medicine, 300 Cedar Street, PO Box 208043, New Haven, CT, 06520, USA.
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10
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Cantuti-Castelvetri L, Maravilla E, Marshall M, Tamayo T, D'auria L, Monge J, Jeffries J, Sural-Fehr T, Lopez-Rosas A, Li G, Garcia K, van Breemen R, Vite C, Garcia J, Bongarzone ER. Mechanism of neuromuscular dysfunction in Krabbe disease. J Neurosci 2015; 35:1606-16. [PMID: 25632136 PMCID: PMC4308604 DOI: 10.1523/jneurosci.2431-14.2015] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2014] [Revised: 10/26/2014] [Accepted: 11/26/2014] [Indexed: 02/06/2023] Open
Abstract
The atrophy of skeletal muscles in patients with Krabbe disease is a major debilitating manifestation that worsens their quality of life and limits the clinical efficacy of current therapies. The pathogenic mechanism triggering muscle wasting is unknown. This study examined structural, functional, and metabolic changes conducive to muscle degeneration in Krabbe disease using the murine (twitcher mouse) and canine [globoid cell leukodystrophy (GLD) dog] models. Muscle degeneration, denervation, neuromuscular [neuromuscular junction (NMJ)] abnormalities, and axonal death were investigated using the reporter transgenic twitcher-Thy1.1-yellow fluorescent protein mouse. We found that mutant muscles had significant numbers of smaller-sized muscle fibers, without signs of regeneration. Muscle growth was slow and weak in twitcher mice, with decreased maximum force. The NMJ had significant levels of activated caspase-3 but limited denervation. Mutant NMJ showed reduced surface areas and lower volumes of presynaptic terminals, with depressed nerve control, increased miniature endplate potential (MEPP) amplitude, decreased MEPP frequency, and increased rise and decay rate constants. Twitcher and GLD dog muscles had significant capacity to store psychosine, the neurotoxin that accumulates in Krabbe disease. Mechanistically, muscle defects involved the inactivation of the Akt pathway and activation of the proteasome pathway. Our work indicates that muscular dysfunction in Krabbe disease is compounded by a pathogenic mechanism involving at least the failure of NMJ function, activation of proteosome degradation, and a reduction of the Akt pathway. Akt, which is key for muscle function, may constitute a novel target to complement in therapies for Krabbe disease.
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MESH Headings
- Animals
- Animals, Newborn
- Axons/metabolism
- Axons/pathology
- Bacterial Proteins/genetics
- Bacterial Proteins/metabolism
- Cells, Cultured
- Disease Models, Animal
- Dogs
- Galactosylceramidase/genetics
- Gene Expression Regulation/genetics
- Leukodystrophy, Globoid Cell/complications
- Leukodystrophy, Globoid Cell/genetics
- Leukodystrophy, Globoid Cell/pathology
- Luminescent Proteins/genetics
- Luminescent Proteins/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Muscle Cells/drug effects
- Muscle Cells/metabolism
- Muscle Contraction/genetics
- Muscle, Skeletal/growth & development
- Neuromuscular Diseases/etiology
- Neuromuscular Diseases/metabolism
- Neuromuscular Diseases/pathology
- Psychosine/metabolism
- Receptors, Nicotinic/genetics
- Receptors, Nicotinic/metabolism
- Synaptic Potentials/drug effects
- Synaptic Potentials/genetics
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Affiliation(s)
| | | | - Michael Marshall
- Departments of Anatomy and Cell Biology, Medical Scientist Training Program, University of Illinois at Chicago, Chicago, Illinois 60612, and
| | - Tammy Tamayo
- Physiology and Biophysics, and Medical Scientist Training Program, University of Illinois at Chicago, Chicago, Illinois 60612, and
| | | | | | | | | | | | - Guannan Li
- Medicinal Chemistry and Pharmacognosy and Medical Scientist Training Program, University of Illinois at Chicago, Chicago, Illinois 60612, and
| | | | - Richard van Breemen
- Medicinal Chemistry and Pharmacognosy and Medical Scientist Training Program, University of Illinois at Chicago, Chicago, Illinois 60612, and
| | - Charles Vite
- School of Veterinary Medicine, University of Pennsylvania, Philadelphia 19104
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11
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Compartmental Analysis of Metabolism by 13C Magnetic Resonance Spectroscopy. BRAIN ENERGY METABOLISM 2014. [DOI: 10.1007/978-1-4939-1059-5_13] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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12
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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: 182] [Impact Index Per Article: 16.5] [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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13
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Region- and age-dependent alterations of glial-neuronal metabolic interactions correlate with CNS pathology in a mouse model of globoid cell leukodystrophy. J Cereb Blood Flow Metab 2013; 33:1127-37. [PMID: 23611871 PMCID: PMC3705444 DOI: 10.1038/jcbfm.2013.64] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 02/27/2013] [Accepted: 03/27/2013] [Indexed: 01/20/2023]
Abstract
Globoid cell leukodystrophy (GLD) or Krabbe disease is a lysosomal storage disorder caused by genetic defects in the expression and activity of galactosylceramidase, a key enzyme in the catabolism of myelin-enriched sphingolipids. While there are several histologic, biochemical, and functional studies on GLD, correlations between morphologic and biochemical alterations in central nervous system (CNS) tissues during disease progression are lacking. Here, we combined immunohistochemistry and metabolic analysis using (1)H and (13)C magnetic resonance (MR) spectra of spinal cord, cerebellum, and forebrain to investigate glial-neuronal metabolic interactions and dysfunction in a GLD murine model that recapitulates the human pathology. In order to assess the temporal- and region-dependent disease progression and the potential metabolic correlates, we investigated CNS tissues at mildly symptomatic and fully symptomatic stages of the disease. When compared with age-matched controls, GLD mice showed glucose hypometabolism, alterations in neurotransmitter content, N-acetylaspartate, N-acetylaspartylglutamate, and osmolytes levels. Notably, age- and region-dependent patterns of metabolic disturbances were in close agreement with the progression of astrogliosis, microglia activation, apoptosis, and neurodegeneration. We suggest that MR spectroscopy could be used in vivo to monitor disease progression, as well as ex vivo and in vivo to provide criteria for the outcome of experimental therapies.
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14
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Steinberg JD, Velan SS. Measuring glucose concentrations in the rat brain using echo-time-averaged point resolved spectroscopy at 7 tesla. Magn Reson Med 2012; 70:301-8. [PMID: 22987321 DOI: 10.1002/mrm.24493] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Revised: 07/19/2012] [Accepted: 08/20/2012] [Indexed: 12/15/2022]
Abstract
Glucose has multiple functions in the brain, and there is interest in estimating in vivo concentrations rather than merely the uptake determined by nuclear medicine. Glucose can be estimated using magnetic resonance spectroscopy, but measurement is difficult due to its multiple J-coupled proton signals overlapping with other metabolite signals. To minimize the effect of interfering signals, echo time (TE) values between 60 and 95 ms were averaged, and the loss in signal due to the T2 effect was corrected in both the estimation of glucose concentration and in creation of the basis files for fitting. The effectiveness of the TE-averaging method was evaluated by measuring the glucose concentration in fasted rats before and after feeding. The brain glucose in all rats increased after feeding with fasted and fed glucose-to-creatine ratios of 0.15 ± 0.03 and 0.24 ± 0.04, respectively. Data at a short TE of 13 ms measured ratios of 0.30 ± 0.16 and 0.36 ± 0.24 for the fasted and fed rats, respectively, demonstrating the difficulty in obtaining reliable glucose measurements at short TE. Overall, TE averaging minimizes the influence of macromolecular signals and nearby peaks to give precise, consistent estimates of glucose.
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Affiliation(s)
- Jeffrey D Steinberg
- Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, Agency for Science, Technology and Research, Singapore, Singapore.
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15
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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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16
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Lee CW, Bawle EV. An infant with myoclonic jerks, global developmental delay, and failure to thrive. Clin Pediatr (Phila) 2011; 50:570-2. [PMID: 20488810 DOI: 10.1177/0009922810366736] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Chia-Wen Lee
- Children's Hospital of Michigan, Detroit, MI, USA.
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17
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Affiliation(s)
- Douglas E. Befroy
- Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
- Corresponding author: Douglas E. Befroy, , or Gerald I. Shulman,
| | - Gerald I. Shulman
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut
- Corresponding author: Douglas E. Befroy, , or Gerald I. Shulman,
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18
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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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19
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Sailasuta N, Tran TT, Harris KC, Ross BD. Swift Acetate Glial Assay (SAGA): an accelerated human ¹³C MRS brain exam for clinical diagnostic use. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2010; 207:352-5. [PMID: 20934362 PMCID: PMC2993807 DOI: 10.1016/j.jmr.2010.09.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Revised: 09/15/2010] [Accepted: 09/15/2010] [Indexed: 05/22/2023]
Abstract
We demonstrate a robust procedure for the quantitative characterization of glial metabolism in human brain. In the past, the slope of the uptake and production of enriched label at steady state were used to determine metabolic rates, requiring the patient to be in the magnet for 120-160 min. In the present method, (13)C cerebral metabolite profiles were acquired at steady state alone on a routine clinical MR scanner in 25.6 min. Results obtained from the new short method (SAGA) were comparable to those achieved in a conventional, long method and effective for determination of glial metabolic rate in posterior-parietal and frontal brain regions.
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Affiliation(s)
- Napapon Sailasuta
- Huntington Medical Research Institutes, Pasadena, CA, United States.
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20
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Mountford CE, Stanwell P, Lin A, Ramadan S, Ross B. Neurospectroscopy: the past, present and future. Chem Rev 2010; 110:3060-86. [PMID: 20387805 DOI: 10.1021/cr900250y] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Carolyn E Mountford
- Centre for Clinical Spectroscopy, Department of Radiology, Brigham & Women's Hospital, Harvard Medical School, 4 Blackfan Street, HIM-817, Boston, Massachusetts 02115, USA.
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21
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Li S, Zhang Y, Wang S, Yang J, Ferraris Araneta M, Farris A, Johnson C, Fox S, Innis R, Shen J. In vivo 13C magnetic resonance spectroscopy of human brain on a clinical 3 T scanner using [2-13C]glucose infusion and low-power stochastic decoupling. Magn Reson Med 2009; 62:565-73. [PMID: 19526500 DOI: 10.1002/mrm.22044] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
This study presents the detection of [2-(13)C]glucose metabolism in the carboxylic/amide region in the human brain, and demonstrates that the cerebral metabolism of [2-(13)C]glucose can be studied in human subjects in the presence of severe hardware constraints of widely available 3 T clinical scanners and with low-power stochastic decoupling. In the carboxylic/amide region of human brain, the primary products of (13)C label incorporation from [2-(13)C]glucose into glutamate, glutamine, aspartate, gamma-aminobutyric acid, and N-acetylaspartate were detected. Unlike the commonly used alkanyl region where lipid signals spread over a broad frequency range, the carboxylic carbon signal of lipids was found to be confined to a narrow range centered at 172.5 ppm and present no spectral interference in the absence of lipid suppression. Comparison using phantoms shows that stochastic decoupling is far superior to the commonly used WALTZ sequence at very low decoupling power at 3 T. It was found that glutamine C1 and C5 can be decoupled using stochastic decoupling at 2.2 W, although glutamine protons span a frequency range of approximately 700 Hz. Detailed specific absorption rate analysis was also performed using finite difference time domain numerical simulation.
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Affiliation(s)
- Shizhe Li
- Magnetic Resonance Spectroscopy Core Facility, NIMH, National Institutes of Health, Bethesda, Maryland 20892-1527, USA
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22
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van der Graaf M. In vivo magnetic resonance spectroscopy: basic methodology and clinical applications. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2009; 39:527-40. [PMID: 19680645 PMCID: PMC2841275 DOI: 10.1007/s00249-009-0517-y] [Citation(s) in RCA: 158] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2009] [Revised: 06/12/2009] [Accepted: 06/29/2009] [Indexed: 12/21/2022]
Abstract
The clinical use of in vivo magnetic resonance spectroscopy (MRS) has been limited for a long time, mainly due to its low sensitivity. However, with the advent of clinical MR systems with higher magnetic field strengths such as 3 Tesla, the development of better coils, and the design of optimized radio-frequency pulses, sensitivity has been considerably improved. Therefore, in vivo MRS has become a technique that is routinely used more and more in the clinic. In this review, the basic methodology of in vivo MRS is described-mainly focused on (1)H MRS of the brain-with attention to hardware requirements, patient safety, acquisition methods, data post-processing, and quantification. Furthermore, examples of clinical applications of in vivo brain MRS in two interesting fields are described. First, together with a description of the major resonances present in brain MR spectra, several examples are presented of deviations from the normal spectral pattern associated with inborn errors of metabolism. Second, through examples of MR spectra of brain tumors, it is shown that MRS can play an important role in oncology.
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Affiliation(s)
- Marinette van der Graaf
- Clinical Physics Laboratory, Department of Paediatrics 833, Radboud University Nijmegen Medical Centre, 6500 HB Nijmegen, The Netherlands.
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23
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Fast isotopic exchange between mitochondria and cytosol in brain revealed by relayed 13C magnetization transfer spectroscopy. J Cereb Blood Flow Metab 2009; 29:661-9. [PMID: 19156161 PMCID: PMC2845910 DOI: 10.1038/jcbfm.2008.170] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In vivo 13C magnetic resonance spectroscopy has been applied to studying brain metabolic processes by measuring 13C label incorporation into cytosolic pools such as glutamate and aspartate. However, the rate of exchange between mitochondrial alpha-ketoglutarate/oxaloacetate and cytosolic glutamate/aspartate (Vx) extracted from metabolic modeling has been controversial. Because brain fumarase is exclusively located in the mitochondria, and mitochondrial fumarate is connected to cytosolic aspartate through a chain of fast exchange reactions, it is possible to directly measure Vx from the four-carbon side of the tricarboxylic acid cycle by magnetization transfer. In isoflurane-anesthetized adult rat brain, a relayed 13C magnetization transfer effect on cytosolic aspartate C2 at 53.2 ppm was detected after extensive signal averaging with fumarate C2 at 136.1 ppm irradiated using selective radiofrequency pulses. Quantitative analysis using Bloch-McConnell equations and a four-site exchange model found that Vx approximately 13-19 micromol per g per min (>>VTCA, the tricarboxylic acid cycle rate) when the longitudinal relaxation time of malate C2 was assumed to be within +/-33% of that of aspartate C2. If Vx approximately VTCA, the isotopic exchange between mitochondria and cytosol would be too slow on the time scale of 13C longitudinal relaxation to cause a detectable magnetization transfer effect.
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24
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Xin L, Frenkel H, Mlynárik V, Morgenthaler FD, Gruetter R. Selective resonance suppression1H-[13C] NMR spectroscopy with asymmetric adiabatic RF pulses. Magn Reson Med 2009; 61:260-6. [DOI: 10.1002/mrm.21829] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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25
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Sailasuta N, Robertson LW, Harris KC, Gropman AL, Allen PS, Ross BD. Clinical NOE 13C MRS for neuropsychiatric disorders of the frontal lobe. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2008; 195:219-25. [PMID: 18829354 PMCID: PMC2610418 DOI: 10.1016/j.jmr.2008.09.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2008] [Revised: 08/19/2008] [Accepted: 09/09/2008] [Indexed: 05/02/2023]
Abstract
In this communication, a scheme is described whereby in vivo (13)C MRS can safely be performed in the frontal lobe, a human brain region hitherto precluded on grounds of SAR, but important in being the seat of impaired cognitive function in many neuropsychiatric and developmental disorders. By combining two well known features of (13)C NMR-the use of low power NOE and the focus on (13)C carbon atoms which are only minimally coupled to protons, we are able to overcome the obstacle of SAR and develop means of monitoring the (13)C fluxes of critically important metabolic pathways in frontal brain structures of normal volunteers and patients. Using a combination of low-power WALTZ decoupling, variants of random noise for nuclear overhauser effect enhancement it was possible to reduce power deposition to 20% of the advised maximum specific absorption rate (SAR). In model solutions (13)C signal enhancement achieved with this scheme were comparable to that obtained with WALTZ-4. In human brain, the low power procedure effectively determined glutamine, glutamate and bicarbonate in the posterior parietal brain after [1-(13)C] glucose infusion. The same (13)C enriched metabolites were defined in frontal brain of human volunteers after administration of [1-(13)C] acetate, a recognized probe of glial metabolism. Time courses of incorporation of (13)C into cerebral glutamate, glutamine and bicarbonate were constructed. The results suggest efficacy for measurement of in vivo cerebral metabolic rates of the glutamate-glutamine and tricarboxylic acid cycles in 20 min MR scans in previously inaccessible brain regions in humans at 1.5 T. We predict these will be clinically useful biomarkers in many human neuropsychiatric and genetic conditions.
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Affiliation(s)
- Napapon Sailasuta
- Huntington Medical Research Institutes, Clinical MRS Unit, 10 Pico Street, Pasadena, CA, USA.
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26
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Moreno A, Ross BD, Blüml S. Direct determination of the N-acetyl-l-aspartate synthesis rate in the human brain by 13C MRS and [1-13C]glucose infusion. J Neurochem 2008. [DOI: 10.1046/j.1471-4159.2001.00282.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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27
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Saneto RP, Friedman SD, Shaw DWW. Neuroimaging of mitochondrial disease. Mitochondrion 2008; 8:396-413. [PMID: 18590986 DOI: 10.1016/j.mito.2008.05.003] [Citation(s) in RCA: 145] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2008] [Revised: 05/11/2008] [Accepted: 05/14/2008] [Indexed: 10/22/2022]
Abstract
Mitochondrial disease represents a heterogeneous group of genetic disorders that require a variety of diagnostic tests for proper determination. Neuroimaging may play a significant role in diagnosis. The various modalities of nuclear magnetic resonance imaging (MRI) allow for multiple independent detection procedures that can give important anatomical and metabolic clues for diagnosis. The non-invasive nature of neuroimaging also allows for longitudinal studies. To date, no pathonmonic correlation between specific genetic defect and neuroimaging findings have been described. However, certain neuroimaging results can give important clues that a patient may have a mitochondrial disease. Conventional MRI may show deep gray structural abnormalities or stroke-like lesions that do not respect vascular territories. Chemical techniques such as proton magnetic resonance spectroscopy (MRS) may demonstrate high levels of lactate or succinate. When found, these results are suggestive of a mitochondrial disease. MRI and MRS studies may also show non-specific findings such as delayed myelination or non-specific leukodystrophy picture. However, in the context of other biochemical, structural, and clinical findings, even non-specific findings may support further diagnostic testing for potential mitochondrial disease. Once a diagnosis has been established, these non-invasive tools can also aid in following disease progression and evaluate the effects of therapeutic interventions.
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Affiliation(s)
- Russell P Saneto
- Division of Pediatric Neurology, Children's Hospital and Regional Medical Center/University of Washington, 4800 Sand Point Way NE, Seattle, WA 98105, USA.
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28
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Kanamatsu T, Otsuki T, Tokuno H, Nambu A, Takada M, Okamoto K, Watanabe H, Umeda M, Tsukada Y. Changes in the rates of the tricarboxylic acid (TCA) cycle and glutamine synthesis in the monkey brain with hemiparkinsonism induced by intracarotid infusion of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP): Studies by non-invasive 13C-magnetic resonance spectroscopy. Brain Res 2007; 1181:142-8. [DOI: 10.1016/j.brainres.2007.08.051] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2007] [Revised: 08/21/2007] [Accepted: 08/25/2007] [Indexed: 11/16/2022]
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29
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Mason GF, Petersen KF, de Graaf RA, Shulman GI, Rothman DL. Measurements of the anaplerotic rate in the human cerebral cortex using 13C magnetic resonance spectroscopy and [1-13C] and [2-13C] glucose. J Neurochem 2006; 100:73-86. [PMID: 17076763 PMCID: PMC2995551 DOI: 10.1111/j.1471-4159.2006.04200.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Recent studies in rodent and human cerebral cortex have shown that glutamate-glutamine neurotransmitter cycling is rapid and the major pathway of neuronal glutamate repletion. The rate of the cycle remains controversial in humans, because glutamine may come either from cycling or from anaplerosis via glial pyruvate carboxylase. Most studies have determined cycling from isotopic labeling of glutamine and glutamate using a [1-(13)C]glucose tracer, which provides label through neuronal and glial pyruvate dehydrogenase or via glial pyruvate carboxylase. To measure the anaplerotic contribution, we measured (13)C incorporation into glutamate and glutamine in the occipital-parietal region of awake humans while infusing [2-(13)C]glucose, which labels the C2 and C3 positions of glutamine and glutamate exclusively via pyruvate carboxylase. Relative to [1-(13)C]glucose, [2-(13)C]glucose provided little label to C2 and C3 glutamine and glutamate. Metabolic modeling of the labeling data indicated that pyruvate carboxylase accounts for 6 +/- 4% of the rate of glutamine synthesis, or 0.02 micromol/g/min. Comparison with estimates of human brain glutamine efflux suggests that the majority of the pyruvate carboxylase flux is used for replacing glutamate lost due to glial oxidation and therefore can be considered to support neurotransmitter trafficking. These results are consistent with observations made with arterial-venous differences and radiotracer methods.
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Affiliation(s)
- Graeme F Mason
- Department of Psychiatry, Yale University, School of Medicine, New Haven, Connecticut 06520-8043, USA.
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30
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Selivanov VA, Sukhomlin T, Centelles JJ, Lee PWN, Cascante M. Integration of enzyme kinetic models and isotopomer distribution analysis for studies of in situ cell operation. BMC Neurosci 2006; 7 Suppl 1:S7. [PMID: 17118161 PMCID: PMC1775047 DOI: 10.1186/1471-2202-7-s1-s7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
A current trend in neuroscience research is the use of stable isotope tracers in order to address metabolic processes in vivo. The tracers produce a huge number of metabolite forms that differ according to the number and position of labeled isotopes in the carbon skeleton (isotopomers) and such a large variety makes the analysis of isotopomer data highly complex. On the other hand, this multiplicity of forms does provide sufficient information to address cell operation in vivo. By the end of last millennium, a number of tools have been developed for estimation of metabolic flux profile from any possible isotopomer distribution data. However, although well elaborated, these tools were limited to steady state analysis, and the obtained set of fluxes remained disconnected from their biochemical context. In this review we focus on a new numerical analytical approach that integrates kinetic and metabolic flux analysis. The related computational algorithm estimates the dynamic flux based on the time-dependent distribution of all possible isotopomers of metabolic pathway intermediates that are generated from a labeled substrate. The new algorithm connects specific tracer data with enzyme kinetic characteristics, thereby extending the amount of data available for analysis: it uses enzyme kinetic data to estimate the flux profile, and vice versa, for the kinetic analysis it uses in vivo tracer data to reveal the biochemical basis of the estimated metabolic fluxes.
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Affiliation(s)
- Vitaly A Selivanov
- Department of Biochemistry and Molecular Biology, Faculty of Chemistry, Marti i Franques, 1, 08028 Barcelona, Spain
- CERQT-Parc Cientific de Barcelona, Barcelona, Spain
| | - Tatiana Sukhomlin
- Institute of Theoretical and Experimental Biophysics, Pushchino, 142290, Russia
| | - Josep J Centelles
- Department of Biochemistry and Molecular Biology, Faculty of Chemistry, Marti i Franques, 1, 08028 Barcelona, Spain
| | - Paul WN Lee
- Department of Pediatrics, Harbor-UCLA Medical Center, Research and Education Institute, Torrance, CA 90502, USA
| | - Marta Cascante
- Department of Biochemistry and Molecular Biology, Faculty of Chemistry, Marti i Franques, 1, 08028 Barcelona, Spain
- CERQT-Parc Cientific de Barcelona, Barcelona, Spain
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31
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Xu S, Shen J. In vivo dynamic turnover of cerebral 13C isotopomers from [U-13C]glucose. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2006; 182:221-8. [PMID: 16859940 DOI: 10.1016/j.jmr.2006.07.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2006] [Revised: 06/27/2006] [Accepted: 07/02/2006] [Indexed: 05/11/2023]
Abstract
An INEPT-based (13)C MRS method and a cost-effective and widely available 11.7 Tesla 89-mm bore vertical magnet were used to detect dynamic (13)C isotopomer turnover from intravenously infused [U-(13)C]glucose in a 211 microL voxel located in the adult rat brain. The INEPT-based (1)H-->(13)C polarization transfer method is mostly adiabatic and therefore minimizes signal loss due to B(1) inhomogeneity of the surface coils used. High quality and reproducible data were acquired as a result of combined use of outer volume suppression, ISIS, and the single-shot three-dimensional localization scheme built in the INEPT pulse sequence. Isotopomer patterns of both glutamate C4 at 34.00 ppm and glutamine C4 at 31.38 ppm are dominated first by a doublet originated from labeling at C4 and C5 but not at C3 (with (1)J(C4C5) = 51 Hz) and then by a quartet originated from labeling at C3, C4, and C5 (with (1)J(C3C4) = 35 Hz). A lag in the transition of glutamine C4 pattern from doublet-dominance to quartet dominance as compared to glutamate C4 was observed, which provides an independent verification of the precursor-product relationship between neuronal glutamate and glial glutamine and a significant intercompartmental cerebral glutamate-glutamine cycle between neurons and glial cells.
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Affiliation(s)
- Su Xu
- Molecular Imaging Branch, National Institute of Mental Health, Bethesda, MD 20892, USA
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32
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Shen J. 13C magnetic resonance spectroscopy studies of alterations in glutamate neurotransmission. Biol Psychiatry 2006; 59:883-7. [PMID: 16199016 DOI: 10.1016/j.biopsych.2005.07.042] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2005] [Revised: 07/11/2005] [Accepted: 07/27/2005] [Indexed: 10/25/2022]
Abstract
Over the past a few years, significant progress has been made in refining the in vivo 13C magnetic resonance spectroscopy technique and in applying it to studying the alterations in the glutamate-glutamine cycling flux. Meanwhile, the details of the metabolic modeling are being rigorously debated. Recent evidence against fast alpha-ketoglutarate-glutamate exchange across the mitochondrial membrane is examined. Previous reports have indicated that glutamate release or 13C label incorporation into glutamine is attenuated at elevated concentrations of endogenous gamma-aminobutyric acid (GABA). A recent study has shown that phenelzine administration reduces the glutamate-glutamine cycling flux while raising endogenous GABA levels in vivo. Effects of several metabotropic glutamate receptor agonists and antagonists and brain disorders on the glutamate-glutamine cycle are also summarized.
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Affiliation(s)
- Jun Shen
- Molecular Imaging Branch, Mood and Anxiety Disorders Program, National Institute of Mental Health, Bethesda, Maryland 20892-1527, USA.
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Abstract
The application of MR spectroscopy (MRS) in pediatric brain disorders yields valued information on pathologic processes, such as ischemia, demyelination, gliosis, and neurodegeneration. Because these processes manifest in inborn errors of metabolism, the purposes of this article are to (1) describe the spectral changes that are associated with the relatively common metabolic disorders, with summaries of known spectroscopic features of these disorders; (2) offer suggestions for recognition and distinction of disorders; and (3) provide general guidelines for MRS implementation. Although many conditions have a similar presentation, MRS offers valuable information for the individual patient in diagnosis and therapy when integrated fully into the clinical setting.
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Affiliation(s)
- Kim M Cecil
- Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA.
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Harris K, Lin A, Bhattacharya P, Tran T, Wong W, Ross B. Regulation of NAA-Synthesis in the Human Brain in Vivo: Canavan’s Disease, Alzheimer’s Disease and Schizophrenia. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2006; 576:263-73; discussion 361-3. [PMID: 16802718 DOI: 10.1007/0-387-30172-0_18] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Affiliation(s)
- Kent Harris
- Magnetic Resonance Unit, Huntington Medical Research Institutes, Pasadena, CA, USA
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35
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Abstract
Breakdown of oligodendrocyte-neuron interactions in white matter (WM), such as the loss of myelin, results in axonal dysfunction and hence a disruption of information processing between brain regions. The major feature of leukodystrophies is the lack of proper myelin formation during early development or the onset of myelin loss late in life. These early childhood WM diseases are described as hypomyelination or dysmyelination arising from a primary block in normal myelin synthesis because of a genetic mutation expressed in oligodendrocytes, or failure in myelination secondary to neuronal or astroglial dysfunctions (van der Knaap 2001 Dev. Med. Child Neurol. 43:705-712). Here, we describe the pathophysiological parameters of Canavan disease (CD), caused by genetic mutations of the aspartoacylase (ASPA) gene, a metabolic enzyme restricted in the central nervous system (CNS) to oligodendrocytes. CD presents pathophysiological dysfunctions similar to diseases caused by myelin gene mutations, such as Pelizaeus-Merzbacher disease (PMD) and several animal models, such as myelin deficient rat (md), jimpy (jp), shiverer (sh), and quaking (qk viable) mutant mice. These single gene mutations have pleiotropic effects, whereby the alteration of one myelin gene expression disrupts functional expression of other oligodendrocyte genes with an outcome of hypomyelination/dysmyelination. Among all of the known leukodystrophies, CD is the first disorder, which was approved and tested for the adeno-associated virus vector (AAV)-ASPA gene therapy (Leone et al. 2000 Ann. Neurol. 48:27-38; Janson et al. 2001 Trends Neurosci. 24:706-712) without much success following the first two attempts. ASPA gene delivery attempts in animal models have shown a lowering of N-acetyl L-aspartate and a change in motor functions, while sponginess of the WM, a characteristic of CD remained unchanged (Matalon et al. 2003 Mol. Ther. 7 (5, Part 1):580-587; McPhee et al. 2005 Brain Res. Mol. Brain Res. 135:112-121) even with better viral serotype and delivery of the gene during early phase of development (Klugmann et al. 2005 Mol. Ther. 11:745-753). While different approaches are being sought for the success of gene therapy, there are pivotal developmental questions to address regarding the specific regions of the CNS and cell lineages that become the target for the onset and progression of CD symptoms from early to late stages of development.
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Affiliation(s)
- Shalini Kumar
- Department of Neurobiology, Mental Retardation Research Center, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, California 90095-7332, USA
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36
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Magnetic resonance spectroscopy of neurodegenerative illness. NEURODEGENER DIS 2005. [DOI: 10.1017/cbo9780511544873.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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37
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Mason G, Bendszus M, Meyerhoff D, Hetherington H, Schweinsburg B, Ross B, Taylor M, Krystal J. Magnetic resonance spectroscopic studies of alcoholism: from heavy drinking to alcohol dependence and back again. Alcohol Clin Exp Res 2005; 29:150-158. [PMID: 15895489 DOI: 10.1097/01.alc.0000150010.72739.58] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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38
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Mason GF, Rothman DL. Basic principles of metabolic modeling of NMR (13)C isotopic turnover to determine rates of brain metabolism in vivo. Metab Eng 2004; 6:75-84. [PMID: 14734257 DOI: 10.1016/j.ymben.2003.10.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Metabolic modeling is a necessary part of the analysis of isotopic labeling data that is being obtained in the brain and other organs. Here are explained the basic principles of metabolic modeling of isotopic labeling studies, particularly with regard to (13)C isotopic measurements performed in vivo. The basic elements needed to simulate isotopic flows are described, and how to combine them to perform modeling analyses is explained. Procedures to introduce and evaluate model constraints and simplifications are discussed. The basic principle of isotopomer analysis is explained, as are mechanics of least-squares fitting of simulations to data. Closely related to the fitting is the effect of data scatter, which is discussed in the context of the non-normal distributions of uncertainty that are often seen with (13)C labeling measurements in vivo. This article is meant to provide a general background for investigators to begin to apply metabolic modeling analysis to (13)C isotopic labeling studies performed in vivo.
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Affiliation(s)
- Graeme F Mason
- Department of Psychiatry, School of Medicine, Yale University, N-141 CAB-Magnetic Resonance Center, 300 Cedar Street, PO Box 208043, New Haven, CT 06520-8043, USA.
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Novotny EJ, Fulbright RK, Pearl PL, Gibson KM, Rothman DL. Magnetic resonance spectroscopy of neurotransmitters in human brain. Ann Neurol 2003; 54 Suppl 6:S25-31. [PMID: 12891651 DOI: 10.1002/ana.10697] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Magnetic resonance spectroscopy (MRS) is a noninvasive method that permits measurement of the concentration of specific biochemical compounds in the brain and other organ systems in precisely defined regions guided by MR imaging (MRI). Recently, MRS methods have been developed to measure specific neurotransmitters in the brain. More advanced MRS methods have been developed to measure the synthesis rates and turnover of specific neurotransmitters. These turnover rates can provide measures of brain metabolism similar to radioisotope techniques. Also, investigations of the relationship of brain metabolism and specific neurotransmitter systems are now possible using MRS. Here, we review the MRS techniques and studies of neurotransmitters in the human brain. A discussion of the potential use of these techniques in the context of certain pediatric neurotransmitter disorders will be presented.
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Affiliation(s)
- Edward J Novotny
- Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06520-8064, USA.
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Shic F, Ross B. Automated data processing of [1H-decoupled] 13C MR spectra acquired from human brain in vivo. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2003; 162:259-268. [PMID: 12810010 DOI: 10.1016/s1090-7807(03)00117-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In clinical 13C infusion studies, broadband excitation of 200 ppm of the human brain yields 13C MR spectra with a time resolution of 2-5 min and generates up to 2000 metabolite peaks over 2h. We describe a fast, automated, observer-independent technique for processing [1H-decoupled] 13C spectra. Quantified 13C spectroscopic signals, before and after the administration of [1-13C]glucose and/or [1-13C]acetate in human subjects are determined. Stepwise improvements of data processing are illustrated by examples of normal and pathological results. Variation in analysis of individual 13C resonances ranged between 2 and 14%. Using this method it is possible to reliably identify subtle metabolic effects of brain disease including Alzheimer's disease and epilepsy.
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Mason GF, Falk Petersen K, de Graaf RA, Kanamatsu T, Otsuki T, Shulman GI, Rothman DL. A comparison of (13)C NMR measurements of the rates of glutamine synthesis and the tricarboxylic acid cycle during oral and intravenous administration of [1-(13)C]glucose. BRAIN RESEARCH. BRAIN RESEARCH PROTOCOLS 2003; 10:181-90. [PMID: 12565689 DOI: 10.1016/s1385-299x(02)00217-9] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
13C-labeled glucose is increasingly used in conjunction with magnetic resonance spectroscopy to measure rates of metabolic pathways in the brain in vivo. Most studies of human subjects have used intravenous infusions to administer the labeled compounds, but the procedure is cumbersome and can be uncomfortable for patients with neurological or psychiatric disorders. It may be possible to improve the practicality of the method by administering the glucose orally instead of intravenously. This report describes the performance and comparison of the oral and intravenous protocols in the same subjects. The conclusion is that oral administration does yield the same result as intravenous administration but with lower precision. That sensitivity of the oral protocol may be improved by several ways that are available today.
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Affiliation(s)
- Graeme F Mason
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA.
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42
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Henry PG, Lebon V, Vaufrey F, Brouillet E, Hantraye P, Bloch G. Decreased TCA cycle rate in the rat brain after acute 3-NP treatment measured by in vivo 1H-[13C] NMR spectroscopy. J Neurochem 2002; 82:857-66. [PMID: 12358791 DOI: 10.1046/j.1471-4159.2002.01006.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Inhibition of succinate dehydrogenase (SDH) by the mitochondrial toxin 3-nitropropionic acid (3-NP) has gained acceptance as an animal model of Huntington's disease. In this study 13C NMR spectroscopy was used to measure the tricarboxylic acid (TCA) cycle rate in the rat brain after 3-NP treatment. The time course of both glutamate C4 and C3 13C labelling was monitored in vivo during an infusion of [1-13C]glucose. Data were fitted by a mathematical model to yield the TCA cycle rate (Vtca) and the exchange rate between alpha-ketoglutarate and glutamate (Vx). 3-NP treatment induced a 18% decrease in Vtca from 0.71 +/- 0.02 micro mol/g/min in the control group to 0.58 +/- 0.02 micro mol/g/min in the 3-NP group (p < 0.001). Vx increased from 0.88 +/- 0.08 micro mol/g/min in the control group to 1.33 +/- 0.24 micro mol/g/min in the 3-NP group (p < 0.07). Fitting the C4 glutamate time course alone under the assumption that Vx is much higher than Vtca yielded Vtca=0.43 micro mol/g/min in both groups. These results suggest that both Vtca and Vx are altered during 3-NP treatment, and that both glutamate C4 and C3 labelling time courses are necessary to obtain a reliable measurement of Vtca.
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Affiliation(s)
- Pierre-Gilles Henry
- CEA and UMR CEA-CNRS 2210, Service Hospitalier Frédéric Joliot, Orsay, France
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Abstract
There is an expanding understanding of primary genetic oxidative-phosphorylation disorders and the recognition of new multi-system clinical phenotypes in the energy metabolism diseases. Although initially recognized in association with mitochondrial DNA mutations, there is progress in the more laborious identification of nuclear DNA encoded genes relevant to mitochondrial structure and function. More pathogenic mitochondrial DNA and nuclear DNA mutations have been identified. Diagnosis of these disorders is often difficult and relies on a concurrence of findings, including recognition of a variety of clinical signs and symptoms, biochemical marker screening, electron transport chain enzyme measurements, and mitochondrial DNA or nuclear DNA mutation assay of genes relevant to mitochondrial structure, function or adenosine triphosphate metabolic pathways. Clinical diagnostic assessment now can be augmented by physiologic imaging techniques, including nuclear magnetic resonance spectroscopy and positron emission tomography. These capabilities should be increasingly helpful for studies of clinical progression and therapeutic intervention. Biologic studies, in families and patients, are beginning to address the factors of mitochondrial replication and segregation that underlie cellular/tissue heteroplasmy and clinical variability. Most epigenetic factors affecting organ-specific and phenotypic variability, however, remain to be elaborated.
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Affiliation(s)
- Katherine Sims
- Department of Neurology, Massachusetts General Hospital, Boston, 02129, USA
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Blüml S, Moreno-Torres A, Shic F, Nguy CH, Ross BD. Tricarboxylic acid cycle of glia in the in vivo human brain. NMR IN BIOMEDICINE 2002; 15:1-5. [PMID: 11840547 DOI: 10.1002/nbm.725] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In the brain, acetate is exclusively oxidized by glia. To determine the contribution of glial metabolism to the tricarboxylic acid cycle (TCA), 1-(13)C-acetate was infused in six studies in three normal adult subjects and -one epileptic receiving valproic acid for seizure control. Ten grams of 99% 1-(13)C labeled acetate were infused intravenously as a 3.3% w/v solution over 60 min, during which in vivo 13C MR spectra of the brain were acquired. As expected, 13C label rapidly enriched cerebral bicarbonate, glutamate and glutamine C5. The mean rate of acetate oxidation calculated from steady-state 13C enrichment of bicarbonate in fasted normal subjects was 0.13 +/- 0.03 micromol/g/min (n=4), approximately 20% of the total cerebral TCA cycle rate.
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Affiliation(s)
- S Blüml
- Huntington Medical Research Institutes, Pasadena, California 91105, USA.
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Cavassila S, Deval S, Huegen C, van Ormondt D, Graveron-Demilly D. Current awareness. NMR IN BIOMEDICINE 2001; 14:284-288. [PMID: 11410947 DOI: 10.1002/nbm.670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In order to keep subscribers up-to-date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of NMR in biomedicine. Each bibliography is divided into 9 sections: 1 Books, Reviews ' Symposia; 2 General; 3 Technology; 4 Brain and Nerves; 5 Neuropathology; 6 Cancer; 7 Cardiac, Vascular and Respiratory Systems; 8 Liver, Kidney and Other Organs; 9 Muscle and Orthopaedic. Within each section, articles are listed in alphabetical order with respect to author. If, in the preceding period, no publications are located relevant to any one of these headings, that section will be omitted.
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Affiliation(s)
- S Cavassila
- Laboratoire RMN, CNRS UMR 5012, UCB Lyon I-CPE, Villeurbanne, France
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