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Rivlin M, Perlman O, Navon G. Metabolic brain imaging with glucosamine CEST MRI: in vivo characterization and first insights. Sci Rep 2023; 13:22030. [PMID: 38086821 PMCID: PMC10716494 DOI: 10.1038/s41598-023-48515-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 11/27/2023] [Indexed: 12/18/2023] Open
Abstract
The utility of chemical exchange saturation transfer (CEST) MRI for monitoring the uptake of glucosamine (GlcN), a safe dietary supplement, has been previously demonstrated in detecting breast cancer in both murine and human subjects. Here, we studied and characterized the detectability of GlcN uptake and metabolism in the brain. Following intravenous GlcN administration in mice, CEST brain signals calculated by magnetization transfer ratio asymmetry (MTRasym) analysis, were significantly elevated, mainly in the cortex, hippocampus, and thalamus. The in vivo contrast remained stable during 40 min of examination, which can be attributed to GlcN uptake and its metabolic products accumulation as confirmed using 13C NMR spectroscopic studies of brain extracts. A Lorentzian multi-pool fitting analysis revealed an increase in the hydroxyl, amide, and relayed nuclear Overhauser effect (rNOE) signal components after GlcN treatment. With its ability to cross the blood-brain barrier (BBB), the GlcN CEST technique has the potential to serve as a metabolic biomarker for the diagnosis and monitoring various brain disorders.
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Affiliation(s)
- Michal Rivlin
- School of Chemistry, Tel-Aviv University, Tel-Aviv, Israel
| | - Or Perlman
- Department of Biomedical Engineering, Tel-Aviv University, Tel-Aviv, Israel
- Sagol School of Neuroscience, Tel-Aviv University, Tel-Aviv, Israel
| | - Gil Navon
- School of Chemistry, Tel-Aviv University, Tel-Aviv, Israel.
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2
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Eleftheriou A, Ravotto L, Wyss MT, Warnock G, Siebert A, Zaiss M, Weber B. Simultaneous dynamic glucose-enhanced (DGE) MRI and fiber photometry measurements of glucose in the healthy mouse brain. Neuroimage 2023; 265:119762. [PMID: 36427752 DOI: 10.1016/j.neuroimage.2022.119762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 10/27/2022] [Accepted: 11/21/2022] [Indexed: 11/25/2022] Open
Abstract
Glucose is the main energy source in the brain and its regulated uptake and utilization are important biomarkers of pathological brain function. Glucose Chemical Exchange Saturation Transfer (GlucoCEST) and its time-resolved version Dynamic Glucose-Enhanced MRI (DGE) are promising approaches to monitor glucose and detect tumors, since they are radioactivity-free, do not require 13C labeling and are is easily translatable to the clinics. The main principle of DGE is clear. However, what remains to be established is to which extent the signal reflects vascular, extracellular or intracellular glucose. To elucidate the compartmental contributions to the DGE signal, we coupled it with FRET-based fiber photometry of genetically encoded sensors, a technique that combines quantitative glucose readout with cellular specificity. The glucose sensor FLIIP was used with fiber photometry to measure astrocytic and neuronal glucose changes upon injection of D-glucose, 3OMG and L-glucose, in the anaesthetized murine brain. By correlating the kinetic profiles of the techniques, we demonstrate the presence of a vascular contribution to the signal, especially at early time points after injection. Furthermore, we show that, in the case of the commonly used contrast agent 3OMG, the DGE signal actually anticorrelates with the glucose concentration in neurons and astrocytes.
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Affiliation(s)
- Afroditi Eleftheriou
- University of Zurich, Institute of Pharmacology and Toxicology, Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
| | - Luca Ravotto
- University of Zurich, Institute of Pharmacology and Toxicology, Zurich, Switzerland
| | - Matthias T Wyss
- University of Zurich, Institute of Pharmacology and Toxicology, Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
| | - Geoffrey Warnock
- University of Zurich, Institute of Pharmacology and Toxicology, Zurich, Switzerland
| | - Anita Siebert
- University of Zurich, Institute of Pharmacology and Toxicology, Zurich, Switzerland
| | - Moritz Zaiss
- Institute of Neuroradiology, University Hospital Erlangen, Friedrich-Alexander University Erlangen Nürnberg, Erlangen, Germany; High-field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | - Bruno Weber
- University of Zurich, Institute of Pharmacology and Toxicology, Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland.
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3
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Liu S, Liu Y, Zhang Z, Wang X, Yang Y, Sun K, Yu J, Chiu DT, Wu C. Near-Infrared Optical Transducer for Dynamic Imaging of Cerebrospinal Fluid Glucose in Brain Tumor. Anal Chem 2022; 94:14265-14272. [PMID: 36206033 DOI: 10.1021/acs.analchem.2c02600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Aberrant cerebral glucose metabolism is related to many brain diseases, especially brain tumor. However, it remains challenging to measure the dynamic changes in cerebral glucose. Here, we developed a near-infrared (NIR) optical transducer to sensitively monitor the glucose variations in cerebrospinal fluid in vivo. The transducer consists of an oxygen-sensitive nanoparticle combined with glucose oxidase (GOx), yielding highly sensitive NIR phosphorescence in response to blood glucose change. We demonstrated long-term continuous glucose monitoring by using the NIR transducer. After subcutaneous implantation, the glucose transducer provides a strong luminescence signal that can continuously monitor blood glucose fluctuations for weeks. By using the NIR emission of the transducer, we further observed abnormal dynamic changes in cerebrospinal fluid glucose and quantitatively assessed cerebral glucose uptake rates in transgenic mice bearing brain tumors. This study provides a promising method for the diagnosis of various metabolic diseases with altered glucose metabolism.
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Affiliation(s)
- Siyang Liu
- Harbin Institute of Technology, Harbin 150001, China.,Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Ye Liu
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Zhe Zhang
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Xiaodong Wang
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yicheng Yang
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Kai Sun
- Department of Chemistry and Bioengineering, University of Washington, 4000 15th NE, Seattle, Washington 98195, United States
| | - Jiangbo Yu
- Department of Chemistry and Bioengineering, University of Washington, 4000 15th NE, Seattle, Washington 98195, United States
| | - Daniel T Chiu
- Department of Chemistry and Bioengineering, University of Washington, 4000 15th NE, Seattle, Washington 98195, United States
| | - Changfeng Wu
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen 518055, China
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4
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Wiegand TLT, Sollmann N, Bonke EM, Umeasalugo KE, Sobolewski KR, Plesnila N, Shenton ME, Lin AP, Koerte IK. Translational neuroimaging in mild traumatic brain injury. J Neurosci Res 2021; 100:1201-1217. [PMID: 33789358 DOI: 10.1002/jnr.24840] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 03/09/2021] [Accepted: 03/17/2021] [Indexed: 01/26/2023]
Abstract
Traumatic brain injuries (TBIs) are common with an estimated 27.1 million cases per year. Approximately 80% of TBIs are categorized as mild TBI (mTBI) based on initial symptom presentation. While in most individuals, symptoms resolve within days to weeks, in some, symptoms become chronic. Advanced neuroimaging has the potential to characterize brain morphometric, microstructural, biochemical, and metabolic abnormalities following mTBI. However, translational studies are needed for the interpretation of neuroimaging findings in humans with respect to the underlying pathophysiological processes, and, ultimately, for developing novel and more targeted treatment options. In this review, we introduce the most commonly used animal models for the study of mTBI. We then summarize the neuroimaging findings in humans and animals after mTBI and, wherever applicable, the translational aspects of studies available today. Finally, we highlight the importance of translational approaches and outline future perspectives in the field of translational neuroimaging in mTBI.
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Affiliation(s)
- Tim L T Wiegand
- cBRAIN, Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Ludwig-Maximilians-Universität, Munich, Germany
| | - Nico Sollmann
- cBRAIN, Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Ludwig-Maximilians-Universität, Munich, Germany
- Department of Diagnostic and Interventional Neuroradiology, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
- TUM-Neuroimaging Center, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
- Department of Diagnostic and Interventional Radiology, University Hospital Ulm, Ulm, Germany
| | - Elena M Bonke
- cBRAIN, Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Ludwig-Maximilians-Universität, Munich, Germany
- Graduate School of Systemic Neurosciences, Ludwig-Maximilians-Universität, Munich, Germany
| | - Kosisochukwu E Umeasalugo
- cBRAIN, Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Ludwig-Maximilians-Universität, Munich, Germany
- Graduate School of Systemic Neurosciences, Ludwig-Maximilians-Universität, Munich, Germany
- Institute for Stroke and Dementia Research, Ludwig-Maximilians-Universität, Munich, Germany
| | - Kristen R Sobolewski
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
- Center for Clinical Spectroscopy, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Nikolaus Plesnila
- Institute for Stroke and Dementia Research, Ludwig-Maximilians-Universität, Munich, Germany
- Munich Cluster for Systems Neurology (Synergy), Munich, Germany
| | - Martha E Shenton
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
- Psychiatry Neuroimaging Laboratory, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Alexander P Lin
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
- Center for Clinical Spectroscopy, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
- Psychiatry Neuroimaging Laboratory, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Inga K Koerte
- cBRAIN, Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Ludwig-Maximilians-Universität, Munich, Germany
- Psychiatry Neuroimaging Laboratory, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
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5
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Hsu CH, Lin S, Ho AC, Johnson TD, Wang PC, Scafidi J, Tu TW. Comparison of in vivo and in situ detection of hippocampal metabolites in mouse brain using 1 H-MRS. NMR IN BIOMEDICINE 2021; 34:e4451. [PMID: 33258202 PMCID: PMC8214416 DOI: 10.1002/nbm.4451] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 10/04/2020] [Accepted: 11/06/2020] [Indexed: 05/25/2023]
Abstract
The study of cerebral metabolites relies heavily on detection methods and sample preparation. Animal experiments in vivo require anesthetic agents that can alter brain metabolism, whereas ex vivo experiments demand appropriate fixation methods to preserve the tissue from rapid postmortem degradation. In this study, the metabolic profiles of mouse hippocampi using proton magnetic resonance spectroscopy (1 H-MRS) were compared in vivo and in situ with or without focused beam microwave irradiation (FBMI) fixation. Ten major brain metabolites, including lactate (Lac), N-acetylaspartate (NAA), total choline (tCho), myo-inositol (mIns), glutamine (Gln), glutamate (Glu), aminobutyric acid (GABA), glutathione (GSH), total creatine (tCr) and taurine (Tau), were analyzed using LCModel. After FBMI fixation, the concentrations of Lac, tCho and mIns were comparable with those obtained in vivo under isoflurane, whereas other metabolites were significantly lower. Except for a decrease in NAA and an increase in Tau, all the other metabolites remained stable over 41 hours in FBMI-fixed brains. Without FBMI, the concentrations of mIns (before 2 hours), tCho and GABA were close to those measured in vivo. However, higher Lac (P < .01) and lower NAA, Gln, Glu, GSH, tCr and Tau were observed (P < .01). NAA, Gln, Glu, GSH, tCr and Tau exhibited good temporal stability for at least 20 hours in the unfixed brain, whereas a linear increase of tCho, mIns and GABA was observed. Possible mechanisms of postmortem degradation are discussed. Our results indicate that a proper fixation method is required for in situ detection depending on the targeted metabolites of specific interests in the brain.
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Affiliation(s)
- Chao-Hsiung Hsu
- Molecular Imaging Laboratory, Department of Radiology, Howard University, Washington, DC, USA
| | - Stephen Lin
- Molecular Imaging Laboratory, Department of Radiology, Howard University, Washington, DC, USA
| | - Ai-Chen Ho
- Molecular Imaging Laboratory, Department of Radiology, Howard University, Washington, DC, USA
- Department of Pharmacotherapy and Outcomes Science, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, USA
| | - T. Derek Johnson
- Center for Neuroscience Research, Department of Neurology, Children’s National Hospital, Washington, DC, USA
| | - Paul C. Wang
- Molecular Imaging Laboratory, Department of Radiology, Howard University, Washington, DC, USA
- Department of Electrical Engineering, Fu Jen Catholic University, New Taipei City, Taiwan
| | - Joseph Scafidi
- Center for Neuroscience Research, Department of Neurology, Children’s National Hospital, Washington, DC, USA
| | - Tsang-Wei Tu
- Molecular Imaging Laboratory, Department of Radiology, Howard University, Washington, DC, USA
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6
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Tu TW, Kovacs ZI, Sundby M, Witko JA, Papadakis GZ, Reid WC, Hammoud DA, Frank JA. Diffusion Tensor Imaging and Chemical Exchange Saturation Transfer MRI Evaluation on the Long-Term Effects of Pulsed Focused Ultrasound and Microbubbles Blood Brain Barrier Opening in the Rat. Front Neurosci 2020; 14:908. [PMID: 32982680 PMCID: PMC7478124 DOI: 10.3389/fnins.2020.00908] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 08/05/2020] [Indexed: 11/16/2022] Open
Abstract
Blood-brain barrier opening (BBBO) with pulsed Focused Ultrasound (pFUS) and microbubbles (MB) has received increasing interest as a method for neurotherapeutics of the central nervous system. In general, conventional MRI [i.e., T2w, T2∗w, gadolinium (Gd) enhanced T1w] is used to monitor the effects of pFUS+MB on BBBO and/or assess whether sonication results in parenchymal damage. This study employed multimodal MRI techniques and 18F-Fludeoxyglucose (FDG) PET to evaluate the effects of single and multiple weekly pFUS+MB sessions on morphology and glucose utilization levels in the rat cortex and hippocampus. pFUS was performed with 0.548 MHz transducer with a slow infusion over 1 min of OptisonTM (5–8 × 107 MB) in nine focal points in cortex and four in hippocampus. During pFUS+MB treatment, Gd-T1w was performed at 3 T to confirm BBBO, along with subsequent T2w, T2∗w, DTI and glucose CEST (glucoCEST)-weighted imaging by high field 9.4 T and compared with FDG-PET and immunohistochemistry. Animals receiving a single pFUS+MB exhibited minimal hypointense voxels on T2∗w. Brains receiving multiple pFUS+MB treatments demonstrated persistent T2w and T2∗ abnormalities associated with changes in DTI and glucoCEST when compared to contralateral parenchyma. Decreased glucoCEST contrast was substantiated by FDG-PET in cortex following multiple sonications. Immunohistochemistry showed significantly dilated vessels and decreased neuronal glucose transporter (GLUT3) expression in sonicated cortex and hippocampus without changes in neuronal counts. These results suggest the importance to standardize MRI protocols in concert with advanced imaging techniques when evaluating long term effects of pFUS+MB BBBO in clinical trials for neurological diseases.
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Affiliation(s)
- Tsang-Wei Tu
- Molecular Imaging Laboratory, Department of Radiology, Howard University College of Medicine, Washington, DC, United States.,Frank Laboratory, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health (NIH), Bethesda, MD, United States.,Center for Neuroscience and Regenerative Medicine, Henry Jackson Foundation, Bethesda, MD, United States
| | - Zsofia I Kovacs
- Frank Laboratory, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health (NIH), Bethesda, MD, United States.,Institute for Biomedical Engineering, Swiss Federal Institute of Technology, Zurich, Switzerland
| | - Maggie Sundby
- Frank Laboratory, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health (NIH), Bethesda, MD, United States
| | - Jaclyn A Witko
- Frank Laboratory, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health (NIH), Bethesda, MD, United States.,Center for Neuroscience and Regenerative Medicine, Henry Jackson Foundation, Bethesda, MD, United States
| | - Georgios Z Papadakis
- Center for Infectious Disease Imaging, Clinical Center, National Institutes of Health (NIH), Bethesda, MD, United States
| | - William C Reid
- Center for Infectious Disease Imaging, Clinical Center, National Institutes of Health (NIH), Bethesda, MD, United States
| | - Dima A Hammoud
- Center for Infectious Disease Imaging, Clinical Center, National Institutes of Health (NIH), Bethesda, MD, United States
| | - Joseph A Frank
- Frank Laboratory, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health (NIH), Bethesda, MD, United States.,National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health (NIH), Bethesda, MD, United States
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7
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Shaffer JJ, Mani M, Schmitz SL, Xu J, Owusu N, Wu D, Magnotta VA, Wemmie JA. Proton Exchange Magnetic Resonance Imaging: Current and Future Applications in Psychiatric Research. Front Psychiatry 2020; 11:532606. [PMID: 33192650 PMCID: PMC7542226 DOI: 10.3389/fpsyt.2020.532606] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 09/02/2020] [Indexed: 12/20/2022] Open
Abstract
Proton exchange provides a powerful contrast mechanism for magnetic resonance imaging (MRI). MRI techniques sensitive to proton exchange provide new opportunities to map, with high spatial and temporal resolution, compounds important for brain metabolism and function. Two such techniques, chemical exchange saturation transfer (CEST) and T1 relaxation in the rotating frame (T1ρ), are emerging as promising tools in the study of neurological and psychiatric illnesses to study brain metabolism. This review describes proton exchange for non-experts, highlights the current status of proton-exchange MRI, and presents advantages and drawbacks of these techniques compared to more traditional methods of imaging brain metabolism, including positron emission tomography (PET) and MR spectroscopy (MRS). Finally, this review highlights new frontiers for the use of CEST and T1ρ in brain research.
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Affiliation(s)
- Joseph J Shaffer
- Department of Radiology, University of Iowa, Iowa City, IA, United States
| | - Merry Mani
- Department of Radiology, University of Iowa, Iowa City, IA, United States
| | - Samantha L Schmitz
- Department of Psychiatry, University of Iowa, Iowa City, IA, United States
| | - Jia Xu
- Department of Radiology, University of Iowa, Iowa City, IA, United States
| | - Nana Owusu
- Department of Radiology, University of Iowa, Iowa City, IA, United States.,Pappajohn Biomedical Institute, University of Iowa, Iowa City, IA, United States.,Department of Biomedical Engineering, University of Iowa, Iowa City, IA, United States
| | - Dee Wu
- Department of Radiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Vincent A Magnotta
- Department of Radiology, University of Iowa, Iowa City, IA, United States.,Department of Psychiatry, University of Iowa, Iowa City, IA, United States.,Department of Biomedical Engineering, University of Iowa, Iowa City, IA, United States
| | - John A Wemmie
- Department of Psychiatry, University of Iowa, Iowa City, IA, United States.,Pappajohn Biomedical Institute, University of Iowa, Iowa City, IA, United States.,Department of Veterans Affairs Medical Center, Iowa City, IA, United States.,Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA, United States.,Department of Neurosurgery, University of Iowa, Iowa City, IA, United States
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8
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Bodnar CN, Roberts KN, Higgins EK, Bachstetter AD. A Systematic Review of Closed Head Injury Models of Mild Traumatic Brain Injury in Mice and Rats. J Neurotrauma 2019; 36:1683-1706. [PMID: 30661454 PMCID: PMC6555186 DOI: 10.1089/neu.2018.6127] [Citation(s) in RCA: 98] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Mild TBI (mTBI) is a significant health concern. Animal models of mTBI are essential for understanding mechanisms, and pathological outcomes, as well as to test therapeutic interventions. A variety of closed head models of mTBI that incorporate different aspects (i.e., biomechanics) of the mTBI have been reported. The aim of the current review was to compile a comprehensive list of the closed head mTBI rodent models, along with the common data elements, and outcomes, with the goal to summarize the current state of the field. Publications were identified from a search of PubMed and Web of Science and screened for eligibility following PRISMA guidelines. Articles were included that were closed head injuries in which the authors classified the injury as mild in rats or mice. Injury model and animal-specific common data elements, as well as behavioral and histological outcomes, were collected and compiled from a total of 402 articles. Our results outline the wide variety of methods used to model mTBI. We also discovered that female rodents and both young and aged animals are under-represented in experimental mTBI studies. Our findings will aid in providing context comparing the injury models and provide a starting point for the selection of the most appropriate model of mTBI to address a specific hypothesis. We believe this review will be a useful starting place for determining what has been done and what knowledge is missing in the field to reduce the burden of mTBI.
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Affiliation(s)
- Colleen N. Bodnar
- Department of Neuroscience, University of Kentucky, Lexington, Kentucky
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky
| | - Kelly N. Roberts
- Department of Neuroscience, University of Kentucky, Lexington, Kentucky
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky
| | - Emma K. Higgins
- Department of Neuroscience, University of Kentucky, Lexington, Kentucky
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky
| | - Adam D. Bachstetter
- Department of Neuroscience, University of Kentucky, Lexington, Kentucky
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky
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9
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Yanez Lopez M, Pardon MC, Baiker K, Prior M, Yuchun D, Agostini A, Bai L, Auer DP, Faas HM. Myoinositol CEST signal in animals with increased Iba-1 levels in response to an inflammatory challenge-Preliminary findings. PLoS One 2019; 14:e0212002. [PMID: 30789943 PMCID: PMC6383890 DOI: 10.1371/journal.pone.0212002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 12/08/2018] [Indexed: 12/21/2022] Open
Abstract
Neuroinflammation plays an important role in the pathogenesis of a range of brain disorders. Non-invasive imaging of neuroinflammation is critical to help improve our understanding of the underlying disease mechanisms, monitor therapies and guide drug development. Generally, MRI lacks specificity to molecular imaging biomarkers, but molecular MR imaging based on chemical exchange saturation transfer (CEST) can potentially detect changes of myoinositol, a putative glial marker that may index neuroinflammation. In this pilot study we aimed to investigate, through validation with immunohistochemistry and in vivo magnetic resonance spectroscopy (MRS), whether CEST imaging can reflect the microglial response to a mild inflammatory challenge with lipopolysaccharide (LPS), in the APPSwe/ PS1 mouse model of Alzheimer’s disease and wild type controls. The response to the immune challenge was variable and did not align with genotype. Animals with a strong response to LPS (Iba1+, n = 6) showed an increase in CEST contrast compared with those who did not (Iba1-, n = 6). Changes of myoinositol levels after LPS were not significant. We discuss the difficulties of this mild inflammatory model, the role of myoinositol as a glial biomarker, and the technical challenges of CEST imaging at 0.6ppm.
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Affiliation(s)
- Maria Yanez Lopez
- Sir Peter Mansfield Imaging Centre, School of Medicine, The University of Nottingham, Nottingham, United Kingdom
| | | | - Kerstin Baiker
- School of Veterinary Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Malcolm Prior
- Medical Imaging Unit, University of Nottingham, Nottingham, United Kingdom
| | - Ding Yuchun
- School of Computer Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Alessandra Agostini
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Li Bai
- School of Computer Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Dorothee P. Auer
- Sir Peter Mansfield Imaging Centre, School of Medicine, The University of Nottingham, Nottingham, United Kingdom
| | - Henryk M. Faas
- Sir Peter Mansfield Imaging Centre, School of Medicine, The University of Nottingham, Nottingham, United Kingdom
- * E-mail:
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10
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Zhuang Z, Shen Z, Chen Y, Dai Z, Zhang X, Mao Y, Zhang B, Zeng H, Chen P, Wu R. Mapping the Changes of Glutamate Using Glutamate Chemical Exchange Saturation Transfer (GluCEST) Technique in a Traumatic Brain Injury Model: A Longitudinal Pilot Study. ACS Chem Neurosci 2019; 10:649-657. [PMID: 30346712 DOI: 10.1021/acschemneuro.8b00482] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Glutamate excitoxicity plays a crucial role in the pathophysiology of traumatic brain injury (TBI) through the initiation of secondary injuries. Glutamate chemical exchange saturation transfer (GluCEST) MRI is a newly developed technique to noninvasively image glutamate in vivo with high sensitivity and spatial resolution. The aim of the present study was to use a rat model of TBI to map changes in brain glutamate distribution and explore the capability of GluCEST imaging for detecting secondary injuries. Sequential GluCEST imaging scans were performed in adult male Sprague-Dawley rats before TBI and at 1, 3, 7, and 14 days after TBI. GluCEST% increased and peaked on day 1 after TBI in the core lesion of injured cortex and peaked on day 3 in the ipsilateral hippocampus, as compared to baseline and controls. GluCEST% gradually declined to baseline by day 14 after TBI. A negative correlation between the GluCEST% of the ipsilateral hippocampus on day 3 and the time in the correct quadrant was observed in injured rats. Immunolabeling for glial fibrillary acidic protein showed significant astrocyte activation in the ipsilateral hippocampus of TBI rats. IL-6 and TNF-α in the core lesion peaked on day 1 postinjury, while those in the ipsilateral hippocampus peaked on day 3. These subsequently gradually declined to sham levels by day 14. It was concluded that GluCEST imaging has potential to be a novel neuroimaging approach for predicting cognitive outcome and to better understand neuroinflammation following TBI.
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Affiliation(s)
- Zerui Zhuang
- Department of Neurosurgery, The Second Affiliated Hospital, Medical College of Shantou University, Shantou 515041, China
| | - Zhiwei Shen
- Department of Radiology, The Second Affiliated Hospital, Medical College of Shantou University, Shantou 515041, China
| | - Yanzi Chen
- Department of Radiology, The Second Affiliated Hospital, Medical College of Shantou University, Shantou 515041, China
| | - Zhuozhi Dai
- Department of Radiology, The Second Affiliated Hospital, Medical College of Shantou University, Shantou 515041, China
| | - Xiaolei Zhang
- Department of Radiology, The Second Affiliated Hospital, Medical College of Shantou University, Shantou 515041, China
| | - Yifei Mao
- Department of Radiology, The Second Affiliated Hospital, Medical College of Shantou University, Shantou 515041, China
| | - Bingna Zhang
- Translational Medicine, The Second Affiliated Hospital, Medical College of Shantou University, Shantou 515041, China
| | - Haiyan Zeng
- Medical College of Shantou University, Shantou 515041, China
| | - Peidong Chen
- Department of Radiology, The Second Affiliated Hospital, Medical College of Shantou University, Shantou 515041, China
| | - Renhua Wu
- Department of Radiology, The Second Affiliated Hospital, Medical College of Shantou University, Shantou 515041, China
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Kovacs ZI, Tu TW, Sundby M, Qureshi F, Lewis BK, Jikaria N, Burks SR, Frank JA. MRI and histological evaluation of pulsed focused ultrasound and microbubbles treatment effects in the brain. Theranostics 2018; 8:4837-4855. [PMID: 30279741 PMCID: PMC6160777 DOI: 10.7150/thno.24512] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 07/26/2018] [Indexed: 12/12/2022] Open
Abstract
Magnetic resonance imaging (MRI)-guided pulsed focused ultrasound (pFUS) combined with microbubbles (MB) contrast agent infusion has been shown to transiently disrupt the blood-brain barrier (BBBD), increasing the delivery of neurotherapeutics to treat central nervous system (CNS) diseases. pFUS interaction with the intravascular MB results in acoustic cavitation forces passing through the neurovascular unit (NVU), inducing BBBD detected on contrast-enhanced MRI. Multiple pFUS+MB exposures in Alzheimer's disease (AD) models are being investigated as a method to clear amyloid plaques by activated microglia or infiltrating immune cells. Since it has been reported that pFUS+MB can induce a sterile inflammatory response (SIR) [1-5] in the rat, the goal of this study was to investigate the potential long-term effects of SIR in the brain following single and six weekly sonications by serial high-resolution MRI and pathology. Methods: Female Sprague Dawley rats weighing 217±16.6 g prior to sonication received bromo-deoxyuridine (BrdU) to tag proliferating cells in the brain. pFUS was performed at 548 kHz, ultrasound burst 10 ms and initial peak negative pressure of 0.3 MPa (in water) for 120 s coupled with a slow infusion of ~460 µL/kg (5-8×107 MB) that started 30 s before and 30 s during sonication. Nine 2 mm focal regions in the left cortex and four regions over the right hippocampus were treated with pFUS+MB. Serial high-resolution brain MRIs at 3 T and 9.4 T were obtained following a single or during the course of six weekly pFUS+MB resulting in BBBD in the left cortex and the right hippocampus. Animals were monitored over 7 to 13 weeks and imaging results were compared to histology. Results: Fewer than half of the rats receiving a single pFUS+MB exposure displayed hypointense voxels on T2*-weighted (w) MRI at week 7 or 13 in the cortex or hippocampus without differences compared to the contralateral side on histograms of T2* maps. Single sonicated rats had evidence of limited microglia activation on pathology compared to the contralateral hemisphere. Six weekly pFUS+MB treatments resulted in pathological changes on T2*w images with multiple hypointense regions, cortical atrophy, along with 50% of rats having persistent BBBD and astrogliosis by MRI. Pathologic analysis of the multiple sonicated animals demonstrated the presence of metallophagocytic Prussian blue-positive cells in the parenchyma with significantly (p<0.05) increased areas of activated astrocytes and microglia, and high numbers of systemic infiltrating CD68+ macrophages along with BrdU+ cells compared to contralateral brain. In addition, multiple treatments caused an increase in the number of hyperphosphorylated Tau (pTau)-positive neurons containing neurofibrillary tangles (NFT) in the sonicated cortex but not in the hippocampus when compared to contralateral brain, which was confirmed by Western blot (WB) (p<0.04). Conclusions: The repeated SIR following multiple pFUS+MB treatments could contribute to changes on MR imaging including persistent BBBD, cortical atrophy, and hypointense voxels on T2w and T2*w images consistent with pathological injury. Moreover, areas of astrogliosis, activated microglia, along with higher numbers of CD68+ infiltrating macrophages and BrdU+ cells were detected in multiple sonicated areas of the cortex and hippocampus. Elevations in pTau and NFT were detected in neurons of the multiple sonicated cortex. Minimal changes on MRI and histology were observed in single pFUS+MB-treated rats at 7 and 13 weeks post sonication. In comparison, animals that received 6 weekly sonications demonstrated evidence on MRI and histology of vascular damage, inflammation and neurodegeneration associated with the NVU commonly observed in trauma. Further investigation is recommended of the long-term effects of multiple pFUS+MB in clinical trials.
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