1
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Tang S, Xu S, Wilder D, Medina AE, Li X, Fiskum GM, Jiang L, Kakulavarapu VR, Long JB, Gullapalli RP, Sajja VS. Longitudinal Biochemical and Behavioral Alterations in a Gyrencephalic Model of Blast-Related Mild Traumatic Brain Injury. Neurotrauma Rep 2024; 5:254-266. [PMID: 38515547 PMCID: PMC10956534 DOI: 10.1089/neur.2024.0002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2024] Open
Abstract
Blast-related traumatic brain injury (bTBI) is a major cause of neurological disorders in the U.S. military that can adversely impact some civilian populations as well and can lead to lifelong deficits and diminished quality of life. Among these types of injuries, the long-term sequelae are poorly understood because of variability in intensity and number of the blast exposure, as well as the range of subsequent symptoms that can overlap with those resulting from other traumatic events (e.g., post-traumatic stress disorder). Despite the valuable insights that rodent models have provided, there is a growing interest in using injury models using species with neuroanatomical features that more closely resemble the human brain. With this purpose, we established a gyrencephalic model of blast injury in ferrets, which underwent blast exposure applying conditions that closely mimic those associated with primary blast injuries to warfighters. In this study, we evaluated brain biochemical, microstructural, and behavioral profiles after blast exposure using in vivo longitudinal magnetic resonance imaging, histology, and behavioral assessments. In ferrets subjected to blast, the following alterations were found: 1) heightened impulsivity in decision making associated with pre-frontal cortex/amygdalar axis dysfunction; 2) transiently increased glutamate levels that are consistent with earlier findings during subacute stages post-TBI and may be involved in concomitant behavioral deficits; 3) abnormally high brain N-acetylaspartate levels that potentially reveal disrupted lipid synthesis and/or energy metabolism; and 4) dysfunction of pre-frontal cortex/auditory cortex signaling cascades that may reflect similar perturbations underlying secondary psychiatric disorders observed in warfighters after blast exposure.
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Affiliation(s)
- Shiyu Tang
- Department of Diagnostic Radiology and Nuclear Medicine, Trauma, and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Center for Advanced Imaging Research (CAIR), Trauma, and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Su Xu
- Department of Diagnostic Radiology and Nuclear Medicine, Trauma, and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Center for Advanced Imaging Research (CAIR), Trauma, and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Donna Wilder
- Blast Induced Neurotrauma Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
| | - Alexandre E. Medina
- Department of Pediatrics, Trauma, and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Xin Li
- Department of Diagnostic Radiology and Nuclear Medicine, Trauma, and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Center for Advanced Imaging Research (CAIR), Trauma, and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Gary M. Fiskum
- Department of Anesthesiology, Trauma, and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Shock, Trauma, and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Li Jiang
- Department of Diagnostic Radiology and Nuclear Medicine, Trauma, and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Center for Advanced Imaging Research (CAIR), Trauma, and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Venkata R. Kakulavarapu
- Blast Induced Neurotrauma Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
| | - Joseph B. Long
- Blast Induced Neurotrauma Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
| | - Rao P. Gullapalli
- Department of Diagnostic Radiology and Nuclear Medicine, Trauma, and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Center for Advanced Imaging Research (CAIR), Trauma, and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, Maryland, USA
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2
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Goodfellow M, Medina JA, Proctor J, Xu S, Gullapalli RP, Rangghran P, Miller C, Vesselinov A, Fiskum G. Combined traumatic brain injury and hemorrhagic shock in ferrets leads to structural, neurochemical, and functional impairments. J Neurotrauma 2022; 39:1442-1452. [PMID: 35481784 DOI: 10.1089/neu.2022.0102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Aeromedical evacuation-relevant hypobaria after traumatic brain injury (TBI) leads to increased neurologic injury and mortality in rats relative to those maintained under normobaria. However, applicability of rodent brain injury research to humans may be limited by differences in neuroanatomy. Therefore, we developed a model in which ferrets are exposed to polytrauma consisting of controlled cortical impact TBI and hemorrhagic shock subjected 24 h later to 6 h of hypobaria or normobaria. Our objective was to determine if the deleterious effects of hypobaria observed in rats, with lissencephalic brains, are also present in a species with a human-like gyrencephalic brain. While no mortality was observed, magnetic resonance spectroscopy (MRS) results obtained 2 days post-injury indicated reduced cortical creatine, N-acetylaspartate, GABA, myo-inositol, and glutamate which was not affected by hypobaria. T2-weighted magnetic resonance imaging (MRI) quantification revealed increased hyperintensity volume representing cortical edema at the site of impact following polytrauma. Hypobaria did not exacerbate this focal edema but did lead to overall reductions in total cortical volume. Both normobaric and hypobaric ferrets exhibited impaired spatial memory 6 days post-injury on the Object Location Test, but no differences were noted between groups. Finally, cortical lesion volume was not exacerbated by hypobaria exposure on day 7 post-injury. Results suggest that air travel 24 h after polytrauma is associated with structural changes in the ferret brain. Future studies should investigate secondary injury from hypobaria following polytrauma in greater detail including alternative outcome measures, timepoints, and exposure to multiple flights.
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Affiliation(s)
- Molly Goodfellow
- University of Maryland School of Medicine, 12264, Anesthesiology, Baltimore, Maryland, United States;
| | - Juliana A Medina
- University of Maryland School of Medicine, Anesthesiology, Baltimore, Maryland, United States;
| | - Julie Proctor
- University of Maryland School of Medicine, Anesthesiology, 685 W Baltimore St, 534 MSTF, Baltimore, Maryland, United States, 21201;
| | - Su Xu
- University of Maryland School of Medicine, Diagnostic Radiology & Nuclear Medicine, Baltimore, Maryland, United States;
| | - Rao P Gullapalli
- University of Maryland School of Medicine, 12264, Diagnostic Radiology & Nuclear Medicine, 670 W Batimore St, Baltimore, Maryland, United States, 21201;
| | - Parisa Rangghran
- University of Maryland School of Medicine, Anesthesiology, Baltimore, Maryland, United States;
| | - Catriona Miller
- University of Maryland School of Medicine, Anesthesiology, Baltimore, Maryland, United States;
| | - Alexandra Vesselinov
- University of Maryland School of Medicine, Anesthesiology, Baltimore, Maryland, United States;
| | - Gary Fiskum
- University of Maryland School of Medicine, 12264, Anesthesiology, Baltimore, Maryland, United States;
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3
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Nucera S, Ruga S, Cardamone A, Coppoletta AR, Guarnieri L, Zito MC, Bosco F, Macrì R, Scarano F, Scicchitano M, Maiuolo J, Carresi C, Mollace R, Cariati L, Mazzarella G, Palma E, Gliozzi M, Musolino V, Cascini GL, Mollace V. MAFLD progression contributes to altered thalamus metabolism and brain structure. Sci Rep 2022; 12:1207. [PMID: 35075185 PMCID: PMC8786899 DOI: 10.1038/s41598-022-05228-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 01/07/2022] [Indexed: 12/02/2022] Open
Abstract
Metabolic associated fatty liver disease (MAFLD), commonly known as non-alcoholic fatty liver disease, represents a continuum of events characterized by excessive hepatic fat accumulation which can progress to nonalcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and in some severe cases hepatocellular carcinoma. MAFLD might be considered as a multisystem disease that affects not only the liver but involves wider implications, relating to several organs and systems, the brain included. The present study aims to investigate changes associated with MAFLD-induced alteration of thalamic metabolism in vivo. DIAMOND (Diet-induced animal model of non-alcoholic fatty liver disease) mice were fed a chow diet and tap water (NC NW) or fat Western Diet (WD SW) for up to 28 weeks. At the baseline and weeks 4, 8, 20, 28 the thalamic neurochemical profile and total cerebral brain volume were evaluated longitudinally in both diet groups using 1H-MRS. To confirm the disease progression, at each time point, a subgroup of animals was sacrificed, the livers excised and placed in formalin. Liver histology was assessed and reviewed by an expert liver pathologist. MAFLD development significantly increases the thalamic levels of total N-acetylaspartate, total creatine, total choline, and taurine. Furthermore, in the WD SW group a reduction in total cerebral brain volume has been observed (p < 0.05 vs NC NW). Our results suggest that thalamic energy metabolism is affected by MAFLD progression. This metabolic imbalance, that is quantifiable by 1H-MRS in vivo, might cause structural damage to brain cells and dysfunctions of neurotransmitter release.
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Affiliation(s)
- Saverio Nucera
- Institute of Research for Food Safety and Health IRC-FSH, Department of Health Sciences, University Magna Graecia of Catanzaro, 88100, Catanzaro, Italy
| | - Stefano Ruga
- Institute of Research for Food Safety and Health IRC-FSH, Department of Health Sciences, University Magna Graecia of Catanzaro, 88100, Catanzaro, Italy
| | - Antonio Cardamone
- Institute of Research for Food Safety and Health IRC-FSH, Department of Health Sciences, University Magna Graecia of Catanzaro, 88100, Catanzaro, Italy
| | - Anna Rita Coppoletta
- Institute of Research for Food Safety and Health IRC-FSH, Department of Health Sciences, University Magna Graecia of Catanzaro, 88100, Catanzaro, Italy
| | - Lorenza Guarnieri
- Institute of Research for Food Safety and Health IRC-FSH, Department of Health Sciences, University Magna Graecia of Catanzaro, 88100, Catanzaro, Italy
| | - Maria Caterina Zito
- Institute of Research for Food Safety and Health IRC-FSH, Department of Health Sciences, University Magna Graecia of Catanzaro, 88100, Catanzaro, Italy
| | - Francesca Bosco
- Institute of Research for Food Safety and Health IRC-FSH, Department of Health Sciences, University Magna Graecia of Catanzaro, 88100, Catanzaro, Italy
| | - Roberta Macrì
- Institute of Research for Food Safety and Health IRC-FSH, Department of Health Sciences, University Magna Graecia of Catanzaro, 88100, Catanzaro, Italy
| | - Federica Scarano
- Institute of Research for Food Safety and Health IRC-FSH, Department of Health Sciences, University Magna Graecia of Catanzaro, 88100, Catanzaro, Italy
| | - Miriam Scicchitano
- Institute of Research for Food Safety and Health IRC-FSH, Department of Health Sciences, University Magna Graecia of Catanzaro, 88100, Catanzaro, Italy
| | - Jessica Maiuolo
- Institute of Research for Food Safety and Health IRC-FSH, Department of Health Sciences, University Magna Graecia of Catanzaro, 88100, Catanzaro, Italy
| | - Cristina Carresi
- Institute of Research for Food Safety and Health IRC-FSH, Department of Health Sciences, University Magna Graecia of Catanzaro, 88100, Catanzaro, Italy
| | - Rocco Mollace
- Institute of Research for Food Safety and Health IRC-FSH, Department of Health Sciences, University Magna Graecia of Catanzaro, 88100, Catanzaro, Italy
| | - Luca Cariati
- Institute of Research for Food Safety and Health IRC-FSH, Department of Health Sciences, University Magna Graecia of Catanzaro, 88100, Catanzaro, Italy
| | - Giuseppe Mazzarella
- Nuclear Medicine Unit, Department of Diagnostic Imaging, University Magna Graecia of Catanzaro, 88100, Catanzaro, Italy
| | - Ernesto Palma
- Institute of Research for Food Safety and Health IRC-FSH, Department of Health Sciences, University Magna Graecia of Catanzaro, 88100, Catanzaro, Italy
| | - Micaela Gliozzi
- Institute of Research for Food Safety and Health IRC-FSH, Department of Health Sciences, University Magna Graecia of Catanzaro, 88100, Catanzaro, Italy.
| | - Vincenzo Musolino
- Institute of Research for Food Safety and Health IRC-FSH, Department of Health Sciences, University Magna Graecia of Catanzaro, 88100, Catanzaro, Italy
| | - Giuseppe Lucio Cascini
- Nuclear Medicine Unit, Department of Diagnostic Imaging, University Magna Graecia of Catanzaro, 88100, Catanzaro, Italy
| | - Vincenzo Mollace
- Institute of Research for Food Safety and Health IRC-FSH, Department of Health Sciences, University Magna Graecia of Catanzaro, 88100, Catanzaro, Italy
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4
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Just N. Proton functional magnetic resonance spectroscopy in rodents. NMR IN BIOMEDICINE 2021; 34:e4254. [PMID: 31967711 DOI: 10.1002/nbm.4254] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 12/04/2019] [Accepted: 12/16/2019] [Indexed: 06/10/2023]
Abstract
Proton functional magnetic resonance spectroscopy (1 H-fMRS) in the human brain is able to assess and quantify the metabolic response due to localized brain activity. Currently, 1 H-fMRS of the human brain is complementary to functional magnetic resonance imaging (fMRI) and a recommended technique at high field strengths (>7 T) for the investigation of neurometabolic couplings, thereby providing insight into the mechanisms underlying brain activity and brain connectivity. Understanding typical healthy brain metabolism during a task is expected to provide a baseline from which to detect and characterize neurochemical alterations associated with various neurological or psychiatric disorders and diseases. It is of paramount importance to resolve fundamental questions related to the regulation of neurometabolic processes. New techniques such as optogenetics may be coupled to fMRI and fMRS to bring more specificity to investigations of brain cell populations during cerebral activation thus enabling a higher link to molecular changes and therapeutic advances. These rather novel techniques are mainly available for rodent applications and trigger renewed interest in animal fMRS. However, rodent fMRS remains fairly confidential due to its inherent low signal-to-noise ratio and its dependence on anesthesia. For instance, the accurate determination of metabolic concentration changes during stimulation requires robust knowledge of the physiological environment of the measured region of interest linked to anesthesia in most cases. These factors may also have a strong influence on B0 homogeneity. Therefore, a degree of calibration of the stimulus strength and duration may be needed for increased knowledge of the underpinnings of cerebral activity. Here, we propose an early review of the current status of 1 H-fMRS in rodents and summarize current difficulties and future perspectives.
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Affiliation(s)
- Nathalie Just
- Department of Clinical Radiology, University Hospital Münster, Germany
- INRAE, Centre, Tours Val de Loire, France
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5
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Pravdivtsev AN, Sönnichsen FD, Hövener JB. In vitro singlet state and zero-quantum encoded magnetic resonance spectroscopy: Illustration with N-acetyl-aspartate. PLoS One 2020; 15:e0239982. [PMID: 33002045 PMCID: PMC7529218 DOI: 10.1371/journal.pone.0239982] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 09/16/2020] [Indexed: 12/20/2022] Open
Abstract
Magnetic resonance spectroscopy (MRS) allows the analysis of biochemical processes non-invasively and in vivo. Still, its application in clinical diagnostics is rare. Routine MRS is limited to spatial, chemical and temporal resolutions of cubic centimetres, mM and minutes. In fact, the signal of many metabolites is strong enough for detection, but the resonances significantly overlap, exacerbating identification and quantification. Besides, the signals of water and lipids are much stronger and dominate the entire spectrum. To suppress the background and isolate selected signals, usually, relaxation times, J-coupling and chemical shifts are used. Here, we propose methods to isolate the signals of selected molecular groups within endogenous metabolites by using long-lived spin states (LLS). We exemplify the method by preparing the LLSs of coupled protons in the endogenous molecules N-acetyl-L-aspartic acid (NAA). First, we store polarization in long-lived, double spin states, followed by saturation pulses before the spin order is converted back to observable magnetization or double quantum filters to suppress background signals. We show that LLS and zero-quantum coherences can be used to selectively prepare and measure the signals of chosen metabolites or drugs in the presence of water, inhomogeneous field and highly concentrated fatty solutions. The strong suppression of unwanted signals achieved allowed us to measure pH as a function of chemical shift difference.
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Affiliation(s)
- Andrey N Pravdivtsev
- Section Biomedical Imaging, Molecular Imaging North Competence Center (MOIN CC), Department of Radiology and Neuroradiology, University Medical Center Kiel, Kiel University, Kiel, Germany
| | - Frank D Sönnichsen
- Otto Diels Institute for Organic Chemistry, Kiel University, Kiel, Germany
| | - Jan-Bernd Hövener
- Section Biomedical Imaging, Molecular Imaging North Competence Center (MOIN CC), Department of Radiology and Neuroradiology, University Medical Center Kiel, Kiel University, Kiel, Germany
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6
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Lanz B, Abaei A, Braissant O, Choi IY, Cudalbu C, Henry PG, Gruetter R, Kara F, Kantarci K, Lee P, Lutz NW, Marjańska M, Mlynárik V, Rasche V, Xin L, Valette J. Magnetic resonance spectroscopy in the rodent brain: Experts' consensus recommendations. NMR IN BIOMEDICINE 2020; 34:e4325. [PMID: 33565219 PMCID: PMC9429976 DOI: 10.1002/nbm.4325] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 03/29/2020] [Accepted: 04/30/2020] [Indexed: 05/21/2023]
Abstract
In vivo MRS is a non-invasive measurement technique used not only in humans, but also in animal models using high-field magnets. MRS enables the measurement of metabolite concentrations as well as metabolic rates and their modifications in healthy animals and disease models. Such data open the way to a deeper understanding of the underlying biochemistry, related disturbances and mechanisms taking place during or prior to symptoms and tissue changes. In this work, we focus on the main preclinical 1H, 31P and 13C MRS approaches to study brain metabolism in rodent models, with the aim of providing general experts' consensus recommendations (animal models, anesthesia, data acquisition protocols). An overview of the main practical differences in preclinical compared with clinical MRS studies is presented, as well as the additional biochemical information that can be obtained in animal models in terms of metabolite concentrations and metabolic flux measurements. The properties of high-field preclinical MRS and the technical limitations are also described.
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Affiliation(s)
- Bernard Lanz
- Laboratory for Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- Sir Peter Mansfield Imaging Centre, School of Medicine, University of Nottingham, Nottingham, United Kingdom
| | - Alireza Abaei
- Core Facility Small Animal Imaging, Ulm University, Ulm, Germany
| | - Olivier Braissant
- Service of Clinical Chemistry, University of Lausanne and University Hospital of Lausanne, Lausanne, Switzerland
| | - In-Young Choi
- Department of Neurology, University of Kansas Medical Center, Kansas City, Kansas, US
| | - Cristina Cudalbu
- Centre d’Imagerie Biomedicale (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Pierre-Gilles Henry
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota, US
| | - Rolf Gruetter
- Laboratory for Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Firat Kara
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, US
| | - Kejal Kantarci
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, US
| | - Phil Lee
- Department of Radiology, University of Kansas Medical Center, Kansas City, Kansas, US
| | | | - Małgorzata Marjańska
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota, US
| | - Vladimír Mlynárik
- High Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Volker Rasche
- Core Facility Small Animal Imaging, Ulm University, Ulm, Germany
| | - Lijing Xin
- Centre d’Imagerie Biomedicale (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Julien Valette
- Commissariat à l’Energie Atomique et aux Energies Alternatives, MIRCen, Fontenay-aux-Roses, France
- Neurodegenerative Diseases Laboratory, Centre National de la Recherche Scientifique, Université Paris-Sud, Université Paris-Saclay, UMR 9199, Fontenay-aux-Roses, France
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7
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Xu S, Tang S, Li X, Iyer SR, Lovering RM. Abnormalities in Brain and Muscle Microstructure and Neurochemistry of the DMD Rat Measured by in vivo Diffusion Tensor Imaging and High Resolution Localized 1H MRS. Front Neurosci 2020; 14:739. [PMID: 32760246 PMCID: PMC7372970 DOI: 10.3389/fnins.2020.00739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 06/22/2020] [Indexed: 12/03/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is an X-linked disorder caused by the lack of dystrophin with progressive degeneration of skeletal muscles. Most studies regarding DMD understandably focus on muscle, but dystrophin is also expressed in the central nervous system, potentially resulting in cognitive and behavioral changes. Animal models are being used for developing more comprehensive neuromonitoring protocols and clinical image acquisition procedures. The recently developed DMD rat is an animal model that parallels the progressive muscle wasting seen in DMD. Here, we studied the brain and temporalis muscle structure and neurochemistry of wild type (WT) and dystrophic (DMD) rats using magnetic resonance imaging and spectroscopy. Both structural and neurochemistry alterations were observed in the DMD rat brain and the temporalis muscle. There was a decrease in absolute brain volume (WT = 1579 mm3; DMD = 1501 mm3; p = 0.039, Cohen’s d = 1.867), but not normalized (WT = 4.27; DMD = 4.02; p = 0.306) brain volume. Diffusion tensor imaging (DTI) revealed structural alterations in the DMD temporalis muscle, with increased mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD). In the DMD rat thalamus, DTI revealed an increase in fractional anisotropy (FA) and a decrease in RD. Smaller normalized brain volume correlated to severity of muscle dystrophy (r = −0.975). Neurochemical changes in the DMD rat brain included increased GABA and NAA in the prefrontal cortex, and GABA in the hippocampus. Such findings could indicate disturbed motor and sensory signaling, resulting in a dysfunctional GABAergic neurotransmission, and an unstable osmoregulation in the dystrophin-null brain.
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Affiliation(s)
- Su Xu
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD, United States.,Center for Advanced Imaging Research, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Shiyu Tang
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD, United States.,Center for Advanced Imaging Research, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Xin Li
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Shama R Iyer
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Richard M Lovering
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD, United States
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8
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Validation of Chronic Restraint Stress Model in Young Adult Rats for the Study of Depression Using Longitudinal Multimodal MR Imaging. eNeuro 2020; 7:ENEURO.0113-20.2020. [PMID: 32669346 PMCID: PMC7396811 DOI: 10.1523/eneuro.0113-20.2020] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 06/15/2020] [Accepted: 07/03/2020] [Indexed: 12/25/2022] Open
Abstract
Prior research suggests that the neurobiological underpinnings of depression include aberrant brain functional connectivity, neurometabolite levels, and hippocampal volume. Chronic restraint stress (CRS) depression model in rats has been shown to elicit behavioral, gene expression, protein, functional connectivity, and hippocampal volume changes similar to those in human depression. However, no study to date has examined the association between behavioral changes and brain changes within the same animals. This study specifically addressed the correlation between the outcomes of behavioral tests and multiple 9.4 T magnetic resonance imaging (MRI) modalities in the CRS model using data collected longitudinally in the same animals. CRS involved placing young adult male Sprague Dawley rats in individual transparent tubes for 2.5 h daily over 13 d. Elevated plus maze (EPM) and forced swim tests (FSTs) confirmed the presence of anxiety-like and depression-like behaviors, respectively, postrestraint. Resting-state functional MRI (rs-fMRI) data revealed hypoconnectivity within the salience and interoceptive networks and hyperconnectivity of several brain regions to the cingulate cortex. Proton magnetic resonance spectroscopy revealed decreased sensorimotor cortical glutamate (Glu), glutamine (Gln), and combined Glu-Gln (Glx) levels. Volumetric analysis of T2-weighted images revealed decreased hippocampal volume. Importantly, these changes parallel those found in human depression, suggesting that the CRS rodent model has utility for translational studies and novel intervention development for depression.
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9
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Dobberthien BJ, Tessier AG, Stanislaus AE, Sawyer MB, Fallone BG, Yahya A. PRESS timings for resolving 13 C 4 -glutamate 1 H signal at 9.4 T: Demonstration in rat with uniformly labelled 13 C-glucose. NMR IN BIOMEDICINE 2019; 32:e4180. [PMID: 31518031 DOI: 10.1002/nbm.4180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 07/30/2019] [Accepted: 08/18/2019] [Indexed: 06/10/2023]
Abstract
MRS of 13 C4 -labelled glutamate (13 C4 -Glu) during an infusion of a carbon-13 (13 C)-labelled substrate, such as uniformly labelled glucose ([U-13 C6 ]-Glc), provides a measure of Glc metabolism. The presented work provides a single-shot indirect 13 C detection technique to quantify the approximately 2.51 ppm 13 C4 -Glu satellite proton (1 H) peak at 9.4 T. The methodology is an optimized point-resolved spectroscopy (PRESS) sequence that minimizes signal contamination from the strongly coupled protons of N-acetylaspartate (NAA), which resonate at approximately 2.49 ppm. J-coupling evolution of protons was characterized numerically and verified experimentally. A (TE1 , TE2 ) combination of (20 ms, 106 ms) was found to be suitable for minimizing NAA signal in the 2.51 ppm 1 H 13 C4 -Glu spectral region, while retaining the 13 C4 -Glu 1 H satellite peak. The efficacy of the technique was verified on phantom solutions and on two rat brains in vivo during an infusion of [U-13 C6 ]-Glc. LCModel was employed for analysis of the in vivo spectra to quantify the 2.51 ppm 1 H 13 C4 -Glu signal to obtain Glu C4 fractional enrichment time courses during the infusions. Cramér-Rao lower bounds of about 8% were obtained for the 2.51 ppm 13 C4 -Glu 1 H satellite peak with the optimal TE combination.
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Affiliation(s)
| | - Anthony G Tessier
- Department of Oncology, University of Alberta, Edmonton, Alberta, Canada
- Department of Medical Physics, Cross Cancer Institute, Edmonton, Alberta, Canada
| | | | - Michael B Sawyer
- Department of Oncology, University of Alberta, Edmonton, Alberta, Canada
| | - B Gino Fallone
- Department of Oncology, University of Alberta, Edmonton, Alberta, Canada
- Department of Medical Physics, Cross Cancer Institute, Edmonton, Alberta, Canada
| | - Atiyah Yahya
- Department of Oncology, University of Alberta, Edmonton, Alberta, Canada
- Department of Medical Physics, Cross Cancer Institute, Edmonton, Alberta, Canada
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10
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Tang S, Xu S, Waddell J, Zhu W, Gullapalli RP, Mooney SM. Functional Connectivity and Metabolic Alterations in Medial Prefrontal Cortex in a Rat Model of Fetal Alcohol Spectrum Disorder: A Resting-State Functional Magnetic Resonance Imaging and in vivo Proton Magnetic Resonance Spectroscopy Study. Dev Neurosci 2019; 41:67-78. [PMID: 30999297 DOI: 10.1159/000499183] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 02/28/2019] [Indexed: 01/08/2023] Open
Abstract
Prenatal ethanol exposure alters brain structure, functional connectivity, and behavior in humans and rats. Behavioral changes include deficits in executive function, which requires cooperative activity between the frontal cortices and other brain regions. In this study, we analyzed the functional connectivity and neurochemical levels of the prefrontal cortex (PFC) using resting-state functional magnetic resonance imaging (rsfMRI) and proton magnetic resonance spectroscopy (1H-MRS) in ethanol-exposed (Eth) and control (Ctr) rats. Pregnant Long-Evans rats were fed a liquid diet containing ethanol (2.1-6.46% v/v ethanol) from gestational days 6 to 21 (Eth). Ctr animals received an isocaloric, isonutritive liquid diet. In young adulthood, male and female offspring underwent in vivo MRI using a 7.0-Tesla system. 1H-MRS from the PFC and whole brain rsfMRI were obtained on the animals. Seed-based functional connectivity analysis was performed with seeds placed in the PFC, matching the voxel of MRS. Male, but not female, Eth rats showed less functional connectivity between PFC and dorsal striatum than Ctr animals. In Eth males glucose levels were significantly lower, and in Eth females lower levels of phosphorylcholine but an increased gamma-aminobutyric acid/glutamate ratio were observed in the PFC compared with Ctr animals. Prenatal ethanol alters brain metabolism and functional connectivity of the PFC in a sex-dependent manner.
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Affiliation(s)
- Shiyu Tang
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA.,Program in Toxicology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Su Xu
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Jaylyn Waddell
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Wenjun Zhu
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Rao P Gullapalli
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Sandra M Mooney
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland, USA,
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Gilbert KM, Schaeffer DJ, Gati JS, Klassen LM, Everling S, Menon RS. Open-source hardware designs for MRI of mice, rats, and marmosets: Integrated animal holders and radiofrequency coils. J Neurosci Methods 2019; 312:65-72. [DOI: 10.1016/j.jneumeth.2018.11.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 11/09/2018] [Accepted: 11/19/2018] [Indexed: 01/24/2023]
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12
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Tang S, Powell EM, Zhu W, Lo FS, Erzurumlu RS, Xu S. Altered Forebrain Functional Connectivity and Neurotransmission in a Kinase-Inactive Met Mouse Model of Autism. Mol Imaging 2019; 18:1536012118821034. [PMID: 30799683 PMCID: PMC6322103 DOI: 10.1177/1536012118821034] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 11/13/2018] [Accepted: 12/03/2018] [Indexed: 12/15/2022] Open
Abstract
MET, the gene encoding the tyrosine kinase receptor for hepatocyte growth factor, is a susceptibility gene for autism spectrum disorder (ASD). Genetically altered mice with a kinase-inactive Met offer a potential model for understanding neural circuit organization changes in autism. Here, we focus on the somatosensory thalamocortical circuitry because distinct somatosensory sensitivity phenotypes accompany ASD, and this system plays a major role in sensorimotor and social behaviors in mice. We employed resting-state functional magnetic resonance imaging and in vivo high-resolution proton MR spectroscopy to examine neuronal connectivity and neurotransmission of wild-type, heterozygous Met-Emx1, and fully inactive homozygous Met-Emx1 mice. Met-Emx1 brains showed impaired maturation of large-scale somatosensory network connectivity when compared with wild-type controls. Significant sex × genotype interaction in both network features and glutamate/gamma-aminobutyric acid (GABA) balance was observed. Female Met-Emx1 brains showed significant connectivity and glutamate/GABA balance changes in the somatosensory thalamocortical system when compared with wild-type brains. The glutamate/GABA ratio in the thalamus was correlated with the connectivity between the somatosensory cortex and the thalamus in heterozygous Met-Emx1 female brains. The findings support the hypothesis that aberrant functioning of the somatosensory thalamocortical system is at the core of the conspicuous somatosensory behavioral phenotypes observed in Met-Emx1 mice.
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Affiliation(s)
- Shiyu Tang
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Elizabeth M. Powell
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | - Wenjun Zhu
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Fu-Sun Lo
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Reha S. Erzurumlu
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Su Xu
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
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Xu S, Zhu W, Wan Y, Wang J, Chen X, Pi L, Lobo MK, Ren B, Ying Z, Morris M, Cao Q. Decreased Taurine and Creatine in the Thalamus May Relate to Behavioral Impairments in Ethanol-Fed Mice: A Pilot Study of Proton Magnetic Resonance Spectroscopy. Mol Imaging 2018; 17:1536012117749051. [PMID: 29318932 PMCID: PMC5768247 DOI: 10.1177/1536012117749051] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Minimal hepatic encephalopathy (MHE) is highly prevalent, observed in up to 80% of patients with liver dysfunction. Minimal hepatic encephalopathy is defined as hepatic encephalopathy with cognitive deficits and no grossly evident neurologic abnormalities. Clinical management may be delayed due to the lack of in vivo quantitative methods needed to reveal changes in brain neurobiochemical biomarkers. To gain insight into the development of alcoholic liver disease–induced neurological dysfunction (NDF), a mouse model of late-stage alcoholic liver fibrosis (LALF) was used to investigate changes in neurochemical levels in the thalamus and hippocampus that relate to behavioral changes. Proton magnetic resonance spectroscopy of the brain and behavioral testing were performed to determine neurochemical alterations and their relationships to behavioral changes in LALF. Glutamine levels were higher in both the thalamus and hippocampus of alcohol-treated mice than in controls. Thalamic levels of taurine and creatine were significantly diminished and strongly correlated with alcohol-induced behavioral changes. Chronic long-term alcohol consumption gives rise to advanced liver fibrosis, neurochemical changes in the nuclei, and behavioral changes which may be linked to NDF. Magnetic resonance spectroscopy represents a sensitive and noninvasive measurement of pathological alterations in the brain, which may provide insight into the pathogenesis underlying the development of MHE.
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Affiliation(s)
- Su Xu
- 1 Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Wenjun Zhu
- 1 Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Yamin Wan
- 1 Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD, USA.,2 The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - JiaBei Wang
- 3 Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD, USA
| | - Xi Chen
- 4 McLean Hospital, Harvard Medical School, Belmont, MA, USA
| | - Liya Pi
- 5 The Department of Pediatrics, University of Florida, Gainesville, FL, USA
| | - Mary Kay Lobo
- 6 Department of Anatomy & Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Bin Ren
- 7 Blood Research Institute, Blood Center of Wisconsin, Department of Medicine, Medical College of Wisconsin Milwaukee, WI, USA
| | - Zhekang Ying
- 8 The Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Michael Morris
- 1 Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Qi Cao
- 1 Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
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14
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Dobberthien BJ, Tessier AG, Yahya A. Improved resolution of glutamate, glutamine and γ-aminobutyric acid with optimized point-resolved spectroscopy sequence timings for their simultaneous quantification at 9.4 T. NMR IN BIOMEDICINE 2018; 31:e3851. [PMID: 29105187 DOI: 10.1002/nbm.3851] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 09/15/2017] [Accepted: 09/25/2017] [Indexed: 06/07/2023]
Abstract
Glutamine (Gln), glutamate (Glu) and γ-aminobutyric acid (GABA) are relevant brain metabolites that can be measured with magnetic resonance spectroscopy (MRS). This work optimizes the point-resolved spectroscopy (PRESS) sequence echo times, TE1 and TE2 , for improved simultaneous quantification of the three metabolites at 9.4 T. Quantification was based on the proton resonances of Gln, Glu and GABA at ≈2.45, ≈2.35 and ≈2.28 ppm, respectively. Glu exhibits overlap with both Gln and GABA; in addition, the Gln peak is contaminated by signal from the strongly coupled protons of N-acetylaspartate (NAA), which resonate at about 2.49 ppm. J-coupling evolution of the protons was characterized numerically and verified experimentally. A {TE1 , TE2 } combination of {106 ms, 16 ms} minimized the NAA signal in the Gln spectral region, whilst retaining Gln, Glu and GABA peaks. The efficacy of the technique was verified on phantom solutions and on rat brain in vivo. LCModel was employed to analyze the in vivo spectra. The average T2 -corrected Gln, Glu and GABA concentrations were found to be 3.39, 11.43 and 2.20 mM, respectively, assuming a total creatine concentration of 8.5 mM. LCModel Cramér-Rao lower bounds (CRLBs) for Gln, Glu and GABA were in the ranges 14-17%, 4-6% and 16-19%, respectively. The optimal TE resulted in concentrations for Gln and GABA that agreed more closely with literature concentrations compared with concentrations obtained from short-TE spectra acquired with a {TE1 , TE2 } combination of {12 ms, 9 ms}. LCModel estimations were also evaluated with short-TE PRESS and with the optimized long TE of {106 ms, 16 ms}, using phantom solutions of known metabolite concentrations. It was shown that concentrations estimated with LCModel can be inaccurate when combined with short-TE PRESS, where there is peak overlap, even when low (<20%) CRLBs are reported.
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Affiliation(s)
| | - Anthony G Tessier
- Department of Oncology, University of Alberta, Edmonton, AB, Canada
- Department of Medical Physics, Cross Cancer Institute, Edmonton, AB, Canada
| | - Atiyah Yahya
- Department of Oncology, University of Alberta, Edmonton, AB, Canada
- Department of Medical Physics, Cross Cancer Institute, Edmonton, AB, Canada
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15
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Tang S, Xu S, Fourney WL, Leiste UH, Proctor JL, Fiskum G, Gullapalli RP. Central Nervous System Changes Induced by Underbody Blast-Induced Hyperacceleration: An in Vivo Diffusion Tensor Imaging and Magnetic Resonance Spectroscopy Study. J Neurotrauma 2017; 34:1972-1980. [DOI: 10.1089/neu.2016.4650] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Affiliation(s)
- Shiyu Tang
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland, Baltimore, Maryland
- Core for Translational Research in Imaging at Maryland, University of Maryland, Baltimore, Maryland
| | - Su Xu
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland, Baltimore, Maryland
- Core for Translational Research in Imaging at Maryland, University of Maryland, Baltimore, Maryland
| | - William L. Fourney
- Department of Mechanical Engineering, University of Maryland, College Park, Maryland
- Center of Energetics Concepts Development, University of Maryland, College Park, Maryland
| | - Ulrich H. Leiste
- Department of Mechanical Engineering, University of Maryland, College Park, Maryland
- Center of Energetics Concepts Development, University of Maryland, College Park, Maryland
| | - Julie L. Proctor
- Department of Anesthesiology, University of Maryland, Baltimore, Maryland
- Shock, Trauma, and Anesthesiology Research Center, University of Maryland, Baltimore, Maryland
| | - Gary Fiskum
- Department of Anesthesiology, University of Maryland, Baltimore, Maryland
- Shock, Trauma, and Anesthesiology Research Center, University of Maryland, Baltimore, Maryland
| | - Rao P. Gullapalli
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland, Baltimore, Maryland
- Core for Translational Research in Imaging at Maryland, University of Maryland, Baltimore, Maryland
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16
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Genetically engineered rat gliomas: PDGF-driven tumor initiation and progression in tv-a transgenic rats recreate key features of human brain cancer. PLoS One 2017; 12:e0174557. [PMID: 28358926 PMCID: PMC5373526 DOI: 10.1371/journal.pone.0174557] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 03/11/2017] [Indexed: 12/13/2022] Open
Abstract
Previously rodent preclinical research in gliomas frequently involved implantation of cell lines such as C6 and 9L into the rat brain. More recently, mouse models have taken over, the genetic manipulability of the mouse allowing the creation of genetically accurate models outweighed the disadvantage of its smaller brain size that limited time allowed for tumor progression. Here we illustrate a method that allows glioma formation in the rat using the replication competent avian-like sarcoma (RCAS) virus / tumor virus receptor-A (tv-a) transgenic system of post-natal cell type-specific gene transfer. The RCAS/tv-a model has emerged as a particularly versatile and accurate modeling technology by enabling spatial, temporal, and cell type-specific control of individual gene transformations and providing de novo formed glial tumors with distinct molecular subtypes mirroring human GBM. Nestin promoter-driven tv-a (Ntv-a) transgenic Sprague-Dawley rat founder lines were created and RCAS PDGFA and p53 shRNA constructs were used to initiate intracranial brain tumor formation. Tumor formation and progression were confirmed and visualized by magnetic resonance imaging (MRI) and spectroscopy. The tumors were analyzed using histopathological and immunofluorescent techniques. All experimental animals developed large, heterogeneous brain tumors that closely resembled human GBM. Median survival was 92 days from tumor initiation and 62 days from the first point of tumor visualization on MRI. Each tumor-bearing animal showed time dependent evidence of malignant progression to high-grade glioma by MRI and neurological examination. Post-mortem tumor analysis demonstrated the presence of several key characteristics of human GBM, including high levels of tumor cell proliferation, pseudopalisading necrosis, microvascular proliferation, invasion of tumor cells into surrounding tissues, peri-tumoral reactive astrogliosis, lymphocyte infiltration, presence of numerous tumor-associated microglia- and bone marrow-derived macrophages, and the formation of stem-like cell niches within the tumor. This transgenic rat model may enable detailed interspecies comparisons of fundamental cancer pathways and clinically relevant experimental imaging procedures and interventions that are limited by the smaller size of the mouse brain.
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17
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Miloushev VZ, Di Gialleonardo V, Salamanca-Cardona L, Correa F, Granlund KL, Keshari KR. Hyperpolarized 13C pyruvate mouse brain metabolism with absorptive-mode EPSI at 1T. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 275:120-126. [PMID: 28061381 PMCID: PMC5554620 DOI: 10.1016/j.jmr.2016.12.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 12/15/2016] [Accepted: 12/19/2016] [Indexed: 06/06/2023]
Abstract
The expected signal in echo-planar spectroscopic imaging experiments was explicitly modeled jointly in spatial and spectral dimensions. Using this as a basis, absorptive-mode type detection can be achieved by appropriate choice of spectral delays and post-processing techniques. We discuss the effects of gradient imperfections and demonstrate the implementation of this sequence at low field (1.05T), with application to hyperpolarized [1-13C] pyruvate imaging of the mouse brain. The sequence achieves sufficient signal-to-noise to monitor the conversion of hyperpolarized [1-13C] pyruvate to lactate in the mouse brain. Hyperpolarized pyruvate imaging of mouse brain metabolism using an absorptive-mode EPSI sequence can be applied to more sophisticated murine disease and treatment models. The simple modifications presented in this work, which permit absorptive-mode detection, are directly translatable to human clinical imaging and generate improved absorptive-mode spectra without the need for refocusing pulses.
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Affiliation(s)
- Vesselin Z Miloushev
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA.
| | - Valentina Di Gialleonardo
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA; Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Lucia Salamanca-Cardona
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA; Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Fabian Correa
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA; Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Kristin L Granlund
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA; Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Kayvan R Keshari
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA; Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA; Weill Cornell Medical College, New York, NY 10065, USA.
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18
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Menshanov PN, Akulov AE. The neurochemical profile of the hippocampus in isoflurane-treated and unanesthetized rat pups. Interdiscip Toxicol 2016; 8:113-7. [PMID: 27486369 PMCID: PMC4961906 DOI: 10.1515/intox-2015-0017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 08/12/2015] [Accepted: 08/13/2015] [Indexed: 11/22/2022] Open
Abstract
In vivo study of cerebral metabolism in neonatal animals by high-resolution magnetic resonance spectroscopy (MRS) is an important tool for deciphering the developmental origins of adult diseases. Up to date, all in vivo spectrum acquisition procedures have been performed in neonatal rodents under anesthesia. However, it is still unknown if the inhaled anesthetic isoflurane, which is commonly used in magnetic resonance imaging studies, could affect metabolite levels in the brain of neonatal rats. Moreover, the unanesthetized MRS preparation that uses neonatal rodent pups is still lacking. Here, a novel restraint protocol was developed for neonatal rats in accordance with the European Directive 2010/63/EU. This protocol shares the same gradation of severity as the protocol for non-invasive magnetic resonance imaging of animals with appropriate sedation or anesthesia. Such immobilization of neonatal rats without anesthesia can be implemented for MRS studies when an interaction between anesthetic and target drugs is expected. Short-term isoflurane treatment did not affect the levels of key metabolites in the hippocampi of anesthetized pups and, in contrast to juvenile and adult rodents, it is suitable for MRS studies in neonatal rats when the interaction between anesthetic and target drugs is not expected.
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Affiliation(s)
- Petr N Menshanov
- Functional Neurogenomics Laboratory, Institute of Cytology and Genetics SBRAS, Russian Academy of Science, Novosibirsk State University MES RF, Novosibirsk, SFO, Russia
| | - Andrey E Akulov
- Laboratory of Ecological Mammalian Genetics, Institute of Cytology and Genetics SBRAS, Russian Academy of Science, Novosibirsk, SFO, Russia
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19
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Xu S, Waddell J, Zhu W, Shi D, Marshall AD, McKenna MC, Gullapalli RP. In vivo longitudinal proton magnetic resonance spectroscopy on neonatal hypoxic-ischemic rat brain injury: Neuroprotective effects of acetyl-L-carnitine. Magn Reson Med 2015; 74:1530-42. [PMID: 25461739 PMCID: PMC4452442 DOI: 10.1002/mrm.25537] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 10/04/2014] [Accepted: 10/30/2014] [Indexed: 12/14/2022]
Abstract
PURPOSE This study evaluated the longitudinal metabolic alterations after neonatal hypoxia-ischemia (HI) in rats and tested the neuroprotective effect of acetyl-L-carnitine (ALCAR) using in vivo proton short-TE Point-RESolved Spectroscopy method. METHODS Rice-Vannucci model was used on 7-day-old Sprague-Dawley rats. Data were acquired from contralateral and ipsilateral cortex and hippocampus, respectively at 4 time points (24-h, 72-h, 7-days, 28-days) post-HI. The effect of subcutaneous administration of ALCAR (100 mg/kg) immediately after HI, at 4-h, 24-h, and 48-h post-HI was determined. RESULTS Significant reductions in glutathione (P < 0.005), myo-inositol (P < 0.002), taurine (P < 0.001), and total creatine (P < 0.005) were observed at 24-h postinjury compared with the control group in the ipsilateral hippocampus of the HI rat pups. ALCAR-treated-HI rats had lower levels of lactate and maintained total creatine at 24-h and had smaller lesion size compared with the HI only rats. CONCLUSION Severe oxidative, osmotic stress, impaired phosphorylation, and a preference for anaerobic glycolysis were found in the ipsilateral hippocampus in the HI pups at 24-h postinjury. ALCAR appeared to have a neuroprotective effect if administered early after HI by serving as an energy substrate and promote oxidative cerebral energy producing and minimize anaerobic glycolysis.
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Affiliation(s)
- Su Xu
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Core for Translational Research in Imaging @ Maryland, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Jaylyn Waddell
- Department of Pediatrics and Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Wenjun Zhu
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Core for Translational Research in Imaging @ Maryland, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Da Shi
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Andrew D Marshall
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Core for Translational Research in Imaging @ Maryland, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Mary C McKenna
- Department of Pediatrics and Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Rao P Gullapalli
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Core for Translational Research in Imaging @ Maryland, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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20
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Xu S, Shi D, Pratt SJP, Zhu W, Marshall A, Lovering RM. Abnormalities in brain structure and biochemistry associated with mdx mice measured by in vivo MRI and high resolution localized (1)H MRS. Neuromuscul Disord 2015; 25:764-72. [PMID: 26236031 DOI: 10.1016/j.nmd.2015.07.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 06/21/2015] [Accepted: 07/06/2015] [Indexed: 01/16/2023]
Abstract
Duchenne muscular dystrophy (DMD), an X-linked disorder caused by the lack of dystrophin, is characterized by the progressive wasting of skeletal muscles. To date, what is known about dystrophin function is derived from studies of dystrophin-deficient animals, with the most common model being the mdx mouse. Most studies on patients with DMD and in mdx mice have focused on skeletal muscle and the development of therapies to reverse, or at least slow, the severe muscle wasting and progressive degeneration. However, dystrophin is also expressed in the CNS. Both mdx mice and patients with DMD can have cognitive and behavioral changes, but studies in the dystrophic brain are limited. We examined the brain structure and metabolites of mature wild type (WT) and mdx mice using magnetic resonance imaging and spectroscopy (MRI/MRS). Both structural and metabolic alterations were observed in the mdx brain. Enlarged lateral ventricles were detected in mdx mice when compared to WT. Diffusion tensor imaging (DTI) revealed elevations in diffusion diffusivities in the prefrontal cortex and a reduction of fractional anisotropy in the hippocampus. Metabolic changes included elevations in phosphocholine and glutathione, and a reduction in γ-aminobutyric acid in the hippocampus. In addition, an elevation in taurine was observed in the prefrontal cortex. Such findings indicate a regional structural change, altered cellular antioxidant defenses, a dysfunction of GABAergic neurotransmission, and a perturbed osmoregulation in the brain lacking dystrophin.
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Affiliation(s)
- Su Xu
- Department of Diagnostic Radiology and Nuclear Medicine, School of Medicine, University of Maryland, Baltimore, MD, USA
| | - Da Shi
- Department of Diagnostic Radiology and Nuclear Medicine, School of Medicine, University of Maryland, Baltimore, MD, USA
| | - Stephen J P Pratt
- Department of Orthopaedics, School of Medicine, University of Maryland, Baltimore, MD, USA
| | - Wenjun Zhu
- Department of Diagnostic Radiology and Nuclear Medicine, School of Medicine, University of Maryland, Baltimore, MD, USA
| | - Andrew Marshall
- Department of Diagnostic Radiology and Nuclear Medicine, School of Medicine, University of Maryland, Baltimore, MD, USA
| | - Richard M Lovering
- Department of Orthopaedics, School of Medicine, University of Maryland, Baltimore, MD, USA.
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21
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Xu S, Gullapalli RP, Frost DO. Olanzapine antipsychotic treatment of adolescent rats causes long term changes in glutamate and GABA levels in the nucleus accumbens. Schizophr Res 2015; 161:452-7. [PMID: 25487700 PMCID: PMC4308953 DOI: 10.1016/j.schres.2014.10.034] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2014] [Revised: 10/20/2014] [Accepted: 10/23/2014] [Indexed: 10/24/2022]
Abstract
Atypical antipsychotic drugs (AAPDs) are widely used in children and adolescents to treat a variety of psychiatric disorders. However, little is known about the long-term effects of AAPD treatment before the brain is fully developed. Indeed, we and others have previously reported that treatment of adolescent rats with olanzapine (OLA; a widely prescribed AAPD) on postnatal days 28-49, under dosing conditions that approximate those employed therapeutically in humans, causes long-term behavioral and neurobiological perturbations. We have begun to study the mechanisms of these effects. Dopamine (DA) and serotonin (5HT) regulate many neurodevelopmental processes. Currently approved AAPDs exert their therapeutic effects principally through their DAergic activities, although in schizophrenia (SZ) and some other diseases for which AAPDs are prescribed, DAergic dysfunction is accompanied by abnormalities of glutamatergic (GLUergic) and γ-aminobutyric acidergic (GABAergic) transmission. Here, we use proton magnetic resonance spectroscopy ((1)H MRS) to investigate the effects of adolescent OLA administration on GABA and GLU levels. We found that the treatment caused long-term reductions in the levels of both GLU and GABA in the nucleus accumbens (NAc) of adult rats treated with OLA during adolescence. The NAc is a key node in the brain's "reward" system, whose function is also disrupted in schizophrenia. Further research into potential, OLA-induced changes in the levels of GLU and GABA in the NAc and other brain areas, and the dynamics and mechanisms of those changes, are an essential step for devising new adjunct therapies for existing AAPDs and for designing new drugs that increase therapeutic effects and reduce long-term abnormalities when administered to pediatric patients.
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Affiliation(s)
- Su Xu
- Dept. of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Rao P Gullapalli
- Dept. of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Douglas O Frost
- Dept. of Pharmacology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Dept. of Psychiatry, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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Hubbard CS, Khan SA, Xu S, Cha M, Masri R, Seminowicz DA. Behavioral, metabolic and functional brain changes in a rat model of chronic neuropathic pain: a longitudinal MRI study. Neuroimage 2014; 107:333-344. [PMID: 25524649 DOI: 10.1016/j.neuroimage.2014.12.024] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 10/31/2014] [Accepted: 12/09/2014] [Indexed: 01/08/2023] Open
Abstract
Peripheral neuropathy often manifests clinically with symptoms of mechanical and cold allodynia. However, the neuroplastic changes associated with peripheral neuropathic pain and the onset and progression of allodynic symptoms remain unclear. Here, we used a chronic neuropathic pain model (spared nerve injury; SNI) to examine functional and metabolic brain changes associated with the development and maintenance of mechanical and cold hypersensitivity, the latter which we assessed both behaviorally and during a novel acetone application paradigm using functional MRI (fMRI). Female Sprague-Dawley rats underwent SNI (n=7) or sham (n=5) surgery to the left hindpaw. Rats were anesthetized and scanned using a 7 T MRI scanner 1 week prior to (pre-injury) and 4 (early/subchronic) and 20 weeks (late/chronic) post-injury. Functional scans were acquired during acetone application to the left hindpaw. (1)H magnetic resonance spectroscopy was also performed to assess SNI-induced metabolic changes in the anterior cingulate cortex (ACC) pre- and 4 weeks post-injury. Mechanical and cold sensitivity, as well as anxiety-like behaviors, were assessed 2 weeks pre-injury, and 2, 5, 9, 14, and 19 weeks post-injury. Stimulus-evoked brain responses (acetone application to the left hindpaw) were analyzed across the pre- and post-injury time points. In response to acetone application during fMRI, SNI rats showed widespread and functionally diverse changes within pain-related brain regions including somatosensory and cingulate cortices and subcortically within the thalamus and the periaqueductal gray. These functional brain changes temporally coincided with early and sustained increases in both mechanical and cold sensitivity. SNI rats also showed increased glutamate within the ACC that correlated with behavioral measures of cold hypersensitivity. Together, our findings suggest that extensive functional reorganization within pain-related brain regions may underlie the development and chronification of allodynic-like behaviors.
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Affiliation(s)
- Catherine S Hubbard
- Department of Neural and Pain Sciences, University of Maryland School of Dentistry, USA
| | - Shariq A Khan
- Department of Neural and Pain Sciences, University of Maryland School of Dentistry, USA
| | - Su Xu
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Core for Translational Research in Imaging @ Maryland, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Myeounghoon Cha
- Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland School of Dentistry, USA
| | - Radi Masri
- Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland School of Dentistry, USA; Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - David A Seminowicz
- Department of Neural and Pain Sciences, University of Maryland School of Dentistry, USA; Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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Tessier AG, Yahya A, Larocque MP, Fallone BG, Syme A. Longitudinal evaluation of the metabolic response of a tumor xenograft model to single fraction radiation therapy using magnetic resonance spectroscopy. Phys Med Biol 2014; 59:5061-72. [PMID: 25119471 DOI: 10.1088/0031-9155/59/17/5061] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Proton magnetic resonance spectroscopy (MRS) was used to evaluate the metabolic profile of human glioblastoma multiform brain tumors grown as xenografts in nude mice before, and at multiple time points after single fraction radiation therapy. Tumors were grown over the thigh in 16 mice in this study, of which 5 served as untreated controls and 11 had their tumors treated to 800 cGy with 200 kVp x-rays. Spectra were acquired within 24 h pre-treatment, and then at 3, 7 and 14 d post-treatment using a 9.4 T animal magnetic resonance (MR) system. For the untreated control tumors, spectra (1-2 per mouse) were acquired at different stages of tumor growth. Spectra were obtained with the PRESS pulse sequence using a 3 × 3 × 3 mm(3) voxel. Analysis was performed with the LCModel software platform. Six metabolites were profiled for this analysis: alanine (Ala), myo-inositol (Ins), taurine (Tau), creatine and phosphocreatine (Cr + PCr), glutamine and glutamate (Glu + Gln), and total choline (glycerophosphocholine + phosphocholine) (GPC + PCh). For the treated cohort, most metabolite/water concentration ratios were found to decrease in the short term at 3 and 7 d post-treatment, followed by an increase at 14 d post-treatment toward pre-treatment values. The lowest concentrations were observed at 7 d post-treatment, with magnitudes (relative to pre-treatment concentration ratios) of: 0.42 ± 24.6% (Ala), 0.43 ± 15.3% (Ins), 0.68 ± 27.9% (Tau), 0.52 ± 14.6% (GPC+PCh), 0.49 ± 21.0% (Cr + PCr) and 0.78 ± 24.5% (Glu + Gln). Control animals did not demonstrate any significant correlation between tumor volume and metabolite concentration, indicating that the observed kinetics were the result of the therapeutic intervention. We have demonstrated the feasibility of using MRS to follow multiple metabolic markers over time for the purpose of evaluating therapeutic response of tumors to radiation therapy. This study provides supporting evidence that metabolite/water concentration ratios have the potential to be used as biomarkers for the assessment of the response to therapy.
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Affiliation(s)
- A G Tessier
- Department of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta T6G 1Z2, Canada
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24
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Jiang L, Ji Y, Voulalas PJ, Keaser M, Xu S, Gullapalli RP, Greenspan J, Masri R. Motor cortex stimulation suppresses cortical responses to noxious hindpaw stimulation after spinal cord lesion in rats. Brain Stimul 2013; 7:182-9. [PMID: 24468093 DOI: 10.1016/j.brs.2013.12.013] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 12/18/2013] [Accepted: 12/23/2013] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Motor cortex stimulation (MCS) is a potentially effective treatment for chronic neuropathic pain. The neural mechanisms underlying the reduction of hyperalgesia and allodynia after MCS are not completely understood. OBJECTIVE To investigate the neural mechanisms responsible for analgesic effects after MCS. We test the hypothesis that MCS attenuates evoked blood oxygen-level dependent signals in cortical areas involved in nociceptive processing in an animal model of chronic neuropathic pain. METHODS We used adult female Sprague-Dawley rats (n = 10) that received unilateral electrolytic lesions of the right spinal cord at the level of C6 (SCL animals). In these animals, we performed magnetic resonance imaging (fMRI) experiments to study the analgesic effects of MCS. On the day of fMRI experiment, 14 days after spinal cord lesion, the animals were anesthetized and epidural bipolar platinum electrodes were placed above the left primary motor cortex. Two 10-min sessions of fMRI were performed before and after a session of MCS (50 μA, 50 Hz, 300 μs, for 30 min). During each fMRI session, the right hindpaw was electrically stimulated (noxious stimulation: 5 mA, 5 Hz, 3 ms) using a block design of 20 s stimulation off and 20 s stimulation on. A general linear model-based statistical parametric analysis was used to analyze whole brain activation maps. Region of interest (ROI) analysis and paired t-test were used to compare changes in activation before and after MCS in these ROI. RESULTS MCS suppressed evoked blood oxygen dependent signals significantly (Family-wise error corrected P < 0.05) and bilaterally in 2 areas heavily implicated in nociceptive processing. These areas consisted of the primary somatosensory cortex and the prefrontal cortex. CONCLUSIONS These findings suggest that, in animals with SCL, MCS attenuates hypersensitivity by suppressing activity in the primary somatosensory cortex and prefrontal cortex.
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Affiliation(s)
- Li Jiang
- Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland School of Dentistry, Baltimore, MD 21201, USA; Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Yadong Ji
- Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland School of Dentistry, Baltimore, MD 21201, USA
| | - Pamela J Voulalas
- Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland School of Dentistry, Baltimore, MD 21201, USA; Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Michael Keaser
- Department of Neural and Pain Sciences, University of Maryland School of Dentistry, Baltimore, MD 21201, USA; Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Su Xu
- Department of Sciences of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Core for Translational Research in Imaging at Maryland (C-TRIM), University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Rao P Gullapalli
- Department of Sciences of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Core for Translational Research in Imaging at Maryland (C-TRIM), University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Joel Greenspan
- Department of Neural and Pain Sciences, University of Maryland School of Dentistry, Baltimore, MD 21201, USA; Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Radi Masri
- Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland School of Dentistry, Baltimore, MD 21201, USA; Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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25
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Zong X, Wang P, Kim SG, Jin T. Sensitivity and source of amine-proton exchange and amide-proton transfer magnetic resonance imaging in cerebral ischemia. Magn Reson Med 2013; 71:118-32. [PMID: 23401310 DOI: 10.1002/mrm.24639] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Revised: 12/19/2012] [Accepted: 12/19/2012] [Indexed: 12/25/2022]
Abstract
PURPOSE Amide-proton transfer (APT) and amine-water proton exchange (APEX) MRI can be viable to map pH-decreasing ischemic regions. However, their exact contributions are unclear. METHODS We measured APEX- and APT-weighted magnetization transfer ratio asymmetry (denoted as APEXw and APTw), apparent diffusion coefficient, T2 , and T1 images and localized proton spectra in rats with permanent middle cerebral artery occlusion at 9.4 T. Phantoms and theoretical studies were also performed. RESULTS Within 1-h postocclusion, APEXw and APTw maps showed hyperintensity (3.1% of M0 ) and hypointensity (-1.8%), respectively, in regions with decreased apparent diffusion coefficient. Ischemia increased lactate and gamma aminobutyric acid concentrations, but decreased glutamate and taurine concentrations. Over time, the APEXw contrast decreased with glutamate, taurine, and creatine, whereas the APTw contrast and lactate level were similar. Phantom and theoretical studies suggest that the source of APEXw signal is mainly from proteins at normal pH, whereas at decreased pH, gamma aminobutyric acid and glutamate contributions increase, inducing the positive APEXw contrast in ischemic regions. The APTw contrast is sensitive to lactate concentration and pH, but contaminated from contributions of the faster APEX processes. CONCLUSION Positive APEXw contrast is more sensitive to ischemia than negative APTw contrast. They may provide complementary tissue metabolic information.
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Affiliation(s)
- Xiaopeng Zong
- Neuroimaging Laboratory, Department of Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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