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Werkman IL, Kövilein J, de Jonge JC, Baron W. Impairing committed cholesterol biosynthesis in white matter astrocytes, but not grey matter astrocytes, enhances in vitro myelination. J Neurochem 2021; 156:624-641. [PMID: 32602556 PMCID: PMC7984098 DOI: 10.1111/jnc.15113] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 05/20/2020] [Accepted: 06/12/2020] [Indexed: 12/20/2022]
Abstract
Remyelination is a regenerative process that is essential to recover saltatory conduction and to prevent neurodegeneration upon demyelination. The formation of new myelin involves the differentiation of oligodendrocyte progenitor cells (OPCs) toward oligodendrocytes and requires high amounts of cholesterol. Astrocytes (ASTRs) modulate remyelination by supplying lipids to oligodendrocytes. Remarkably, remyelination is more efficient in grey matter (GM) than in white matter (WM), which may relate to regional differences in ASTR subtype. Here, we show that a feeding layer of gmASTRs was more supportive to in vitro myelination than a feeding layer of wmASTRs. While conditioned medium from both gmASTRs and wmASTRs accelerated gmOPC differentiation, wmOPC differentiation is enhanced by secreted factors from gmASTRs, but not wmASTRs. In vitro analyses revealed that gmASTRs secreted more cholesterol than wmASTRs. Cholesterol efflux from both ASTR types was reduced upon exposure to pro-inflammatory cytokines, which was mediated via cholesterol transporter ABCA1, but not ABCG1, and correlated with a minor reduction of myelin membrane formation by oligodendrocytes. Surprisingly, a wmASTR knockdown of Fdft1 encoding for squalene synthase (SQS), an enzyme essential for the first committed step in cholesterol biosynthesis, enhanced in vitro myelination. Reduced secretion of interleukin-1β likely by enhanced isoprenylation, and increased unsaturated fatty acid synthesis, both pathways upstream of SQS, likely masked the effect of reduced levels of ASTR-derived cholesterol. Hence, our findings indicate that gmASTRs export more cholesterol and are more supportive to myelination than wmASTRs, but specific inhibition of cholesterol biosynthesis in ASTRs is beneficial for wmASTR-mediated modulation of myelination.
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Affiliation(s)
- Inge L. Werkman
- Biomedical Sciences of Cells & Systemssection Molecular NeurobiologyUniversity of GroningenUniversity Medical Center GroningenGroningenthe Netherlands
- Present address:
Department of BiologyUniversity of VirginiaCharlottesvilleVAUSA
| | - Janine Kövilein
- Biomedical Sciences of Cells & Systemssection Molecular NeurobiologyUniversity of GroningenUniversity Medical Center GroningenGroningenthe Netherlands
| | - Jenny C. de Jonge
- Biomedical Sciences of Cells & Systemssection Molecular NeurobiologyUniversity of GroningenUniversity Medical Center GroningenGroningenthe Netherlands
| | - Wia Baron
- Biomedical Sciences of Cells & Systemssection Molecular NeurobiologyUniversity of GroningenUniversity Medical Center GroningenGroningenthe Netherlands
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2
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Teo W, Caprariello AV, Morgan ML, Luchicchi A, Schenk GJ, Joseph JT, Geurts JJG, Stys PK. Nile Red fluorescence spectroscopy reports early physicochemical changes in myelin with high sensitivity. Proc Natl Acad Sci U S A 2021; 118:e2016897118. [PMID: 33593907 PMCID: PMC7923366 DOI: 10.1073/pnas.2016897118] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The molecular composition of myelin membranes determines their structure and function. Even minute changes to the biochemical balance can have profound consequences for axonal conduction and the synchronicity of neural networks. Hypothesizing that the earliest indication of myelin injury involves changes in the composition and/or polarity of its constituent lipids, we developed a sensitive spectroscopic technique for defining the chemical polarity of myelin lipids in fixed frozen tissue sections from rodent and human. The method uses a simple staining procedure involving the lipophilic dye Nile Red, whose fluorescence spectrum varies according to the chemical polarity of the microenvironment into which the dye embeds. Nile Red spectroscopy identified histologically intact yet biochemically altered myelin in prelesioned tissues, including mouse white matter following subdemyelinating cuprizone intoxication, as well as normal-appearing white matter in multiple sclerosis brain. Nile Red spectroscopy offers a relatively simple yet highly sensitive technique for detecting subtle myelin changes.
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Affiliation(s)
- Wulin Teo
- Department of Clinical Neurosciences, Hotchkiss Brain Institute, University of Calgary Cumming School of Medicine, Calgary, AB T2N 4N1, Canada
| | - Andrew V Caprariello
- Department of Clinical Neurosciences, Hotchkiss Brain Institute, University of Calgary Cumming School of Medicine, Calgary, AB T2N 4N1, Canada
| | - Megan L Morgan
- Department of Clinical Neurosciences, Hotchkiss Brain Institute, University of Calgary Cumming School of Medicine, Calgary, AB T2N 4N1, Canada
| | - Antonio Luchicchi
- Department of Anatomy and Neurosciences, Amsterdam UMC, Vrije Universiteit, Amsterdam Neuroscience, 1081 HZ Amsterdam, The Netherlands
| | - Geert J Schenk
- Department of Anatomy and Neurosciences, Amsterdam UMC, Vrije Universiteit, Amsterdam Neuroscience, 1081 HZ Amsterdam, The Netherlands
| | - Jeffrey T Joseph
- Department of Clinical Neurosciences, Hotchkiss Brain Institute, University of Calgary Cumming School of Medicine, Calgary, AB T2N 4N1, Canada
- Department of Pathology and Laboratory Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Jeroen J G Geurts
- Department of Anatomy and Neurosciences, Amsterdam UMC, Vrije Universiteit, Amsterdam Neuroscience, 1081 HZ Amsterdam, The Netherlands
| | - Peter K Stys
- Department of Clinical Neurosciences, Hotchkiss Brain Institute, University of Calgary Cumming School of Medicine, Calgary, AB T2N 4N1, Canada;
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3
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Su D, Hooshmand MJ, Galvan MD, Nishi RA, Cummings BJ, Anderson AJ. Complement C6 deficiency exacerbates pathophysiology after spinal cord injury. Sci Rep 2020; 10:19500. [PMID: 33177623 PMCID: PMC7659012 DOI: 10.1038/s41598-020-76441-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Accepted: 10/09/2020] [Indexed: 11/25/2022] Open
Abstract
Historically, the membrane attack complex, composed of complement components C5b-9, has been connected to lytic cell death and implicated in secondary injury after a CNS insult. However, studies to date have utilized either non-littermate control rat models, or mouse models that lack significant C5b-9 activity. To investigate what role C5b-9 plays in spinal cord injury and recovery, we generated littermate PVG C6 wildtype and deficient rats and tested functional and histological recovery after moderate contusion injury using the Infinite Horizon Impactor. We compare the effect of C6 deficiency on recovery of locomotor function and histological injury parameters in PVG rats under two conditions: (1) animals maintained as separate C6 WT and C6-D homozygous colonies; and (2) establishment of a heterozygous colony to generate C6 WT and C6-D littermate controls. The results suggest that maintenance of separate homozygous colonies is inadequate for testing the effect of C6 deficiency on locomotor and histological recovery after SCI, and highlight the importance of using littermate controls in studies involving genetic manipulation of the complement cascade.
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Affiliation(s)
- Diane Su
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, CA, USA
| | - Mitra J Hooshmand
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, CA, USA
- Institute for Memory Impairments and Neurological Disorders (iMIND), University of California, Irvine, Irvine, CA, USA
- Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, Irvine, CA, USA
| | - Manuel D Galvan
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, CA, USA
| | - Rebecca A Nishi
- Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, Irvine, CA, USA
| | - Brian J Cummings
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, CA, USA
- Institute for Memory Impairments and Neurological Disorders (iMIND), University of California, Irvine, Irvine, CA, USA
- Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, Irvine, CA, USA
- Department of Physical Medicine and Rehabilitation, University of California, Irvine, CA, USA
| | - Aileen J Anderson
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, CA, USA.
- Institute for Memory Impairments and Neurological Disorders (iMIND), University of California, Irvine, Irvine, CA, USA.
- Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, Irvine, CA, USA.
- Department of Physical Medicine and Rehabilitation, University of California, Irvine, CA, USA.
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4
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Nicastro N, Malpetti M, Mak E, Williams GB, Bevan-Jones WR, Carter SF, Passamonti L, Fryer TD, Hong YT, Aigbirhio FI, Rowe JB, O'Brien JT. Gray matter changes related to microglial activation in Alzheimer's disease. Neurobiol Aging 2020; 94:236-242. [PMID: 32663716 PMCID: PMC7456794 DOI: 10.1016/j.neurobiolaging.2020.06.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 05/28/2020] [Accepted: 06/11/2020] [Indexed: 12/14/2022]
Abstract
Neuroinflammation is increasingly recognized as playing a key pathogenetic role in Alzheimer's disease (AD). We examined the relationship between in vivo neuroinflammation and gray matter (GM) changes. Twenty-eight subjects with clinically probable AD (n = 14) and amyloid-positive mild cognitive impairment (n = 14) (age 71.9 ± 8.4 years, 46% female) and 24 healthy controls underwent structural 3T brain MRI. AD/mild cognitive impairment participants exhibited GM atrophy and cortical thinning in AD-related temporoparietal regions (false discovery rate-corrected p < 0.05). Patients also showed increased microglial activation in temporal cortices. Higher 11C-PK11195 binding in these regions was associated with reduced volume and cortical thickness in parietal, occipital, and cingulate areas (false discovery rate p < 0.05). Hippocampal GM atrophy and parahippocampal cortical thinning were related to worse cognition (p < 0.05), but these effects were not mediated by microglial activation. This study demonstrates an association between in vivo microglial activation and markers of GM damage in AD, positioning neuroinflammation as a potential target for immunotherapeutic strategies.
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Affiliation(s)
- Nicolas Nicastro
- Department of Psychiatry, University of Cambridge, Cambridge, UK; Department of Clinical Neurosciences, Geneva University Hospitals, Switzerland.
| | - Maura Malpetti
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Elijah Mak
- Department of Psychiatry, University of Cambridge, Cambridge, UK
| | - Guy B Williams
- Wolfson Brain Imaging Centre, Cognition University of Cambridge, Cambridge, UK
| | | | - Stephen F Carter
- Department of Psychiatry, University of Cambridge, Cambridge, UK
| | - Luca Passamonti
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK; Consiglio Nazionale delle Ricerche (CNR), Istituto di Bioimmagini e Fisiologia Molecolare (IBFM), Milano, Italy
| | - Tim D Fryer
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK; Wolfson Brain Imaging Centre, Cognition University of Cambridge, Cambridge, UK
| | - Young T Hong
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK; Wolfson Brain Imaging Centre, Cognition University of Cambridge, Cambridge, UK
| | | | - James B Rowe
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK; Medical Research Council Cognition and Brain Sciences Unit, Cambridge, UK
| | - John T O'Brien
- Department of Psychiatry, University of Cambridge, Cambridge, UK
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5
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Hagiwara A, Hori M, Kamagata K, Warntjes M, Matsuyoshi D, Nakazawa M, Ueda R, Andica C, Koshino S, Maekawa T, Irie R, Takamura T, Kumamaru KK, Abe O, Aoki S. Myelin Measurement: Comparison Between Simultaneous Tissue Relaxometry, Magnetization Transfer Saturation Index, and T 1w/T 2w Ratio Methods. Sci Rep 2018; 8:10554. [PMID: 30002497 PMCID: PMC6043493 DOI: 10.1038/s41598-018-28852-6] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 07/02/2018] [Indexed: 01/06/2023] Open
Abstract
Magnetization transfer (MT) imaging has been widely used for estimating myelin content in the brain. Recently, two other approaches, namely simultaneous tissue relaxometry of R1 and R2 relaxation rates and proton density (SyMRI) and the ratio of T1-weighted to T2-weighted images (T1w/T2w ratio), were also proposed as methods for measuring myelin. SyMRI and MT imaging have been reported to correlate well with actual myelin by histology. However, for T1w/T2w ratio, such evidence is limited. In 20 healthy adults, we examined the correlation between these three methods, using MT saturation index (MTsat) for MT imaging. After calibration, white matter (WM) to gray matter (GM) contrast was the highest for SyMRI among these three metrics. Even though SyMRI and MTsat showed strong correlation in the WM (r = 0.72), only weak correlation was found between T1w/T2w and SyMRI (r = 0.45) or MTsat (r = 0.38) (correlation coefficients significantly different from each other, with p values < 0.001). In subcortical and cortical GM, these measurements showed moderate to strong correlations to each other (r = 0.54 to 0.78). In conclusion, the high correlation between SyMRI and MTsat indicates that both methods are similarly suited to measure myelin in the WM, whereas T1w/T2w ratio may be less optimal.
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Affiliation(s)
- Akifumi Hagiwara
- Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan.
- Department of Radiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
| | - Masaaki Hori
- Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan
| | - Koji Kamagata
- Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan
| | - Marcel Warntjes
- SyntheticMR AB, Linköping, Sweden
- Center for Medical Imaging Science and Visualization (CMIV), Linköping, Sweden
| | - Daisuke Matsuyoshi
- Araya Inc., Tokyo, Japan
- Research Institute for Science and Engineering, Waseda University, Waseda, Japan
- Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
| | - Misaki Nakazawa
- Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan
| | - Ryo Ueda
- Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan
- Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo, Japan
- Office of Radiation Technology, Keio University Hospital, Tokyo, Japan
| | - Christina Andica
- Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan
| | - Saori Koshino
- Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan
- Department of Radiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Tomoko Maekawa
- Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan
- Department of Radiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Ryusuke Irie
- Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan
- Department of Radiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Tomohiro Takamura
- Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan
| | | | - Osamu Abe
- Department of Radiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Shigeki Aoki
- Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan
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6
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Poplawski GHD, Lie R, Hunt M, Kumamaru H, Kawaguchi R, Lu P, Schäfer MKE, Woodruff G, Robinson J, Canete P, Dulin JN, Geoffroy CG, Menzel L, Zheng B, Coppola G, Tuszynski MH. Adult rat myelin enhances axonal outgrowth from neural stem cells. Sci Transl Med 2018; 10:eaal2563. [PMID: 29794059 PMCID: PMC8377986 DOI: 10.1126/scitranslmed.aal2563] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 06/07/2017] [Accepted: 11/17/2017] [Indexed: 12/18/2022]
Abstract
Axon regeneration after spinal cord injury (SCI) is attenuated by growth inhibitory molecules associated with myelin. We report that rat myelin stimulated the growth of axons emerging from rat neural progenitor cells (NPCs) transplanted into sites of SCI in adult rat recipients. When plated on a myelin substrate, neurite outgrowth from rat NPCs and from human induced pluripotent stem cell (iPSC)-derived neural stem cells (NSCs) was enhanced threefold. In vivo, rat NPCs and human iPSC-derived NSCs extended greater numbers of axons through adult central nervous system white matter than through gray matter and preferentially associated with rat host myelin. Mechanistic investigations excluded Nogo receptor signaling as a mediator of stem cell-derived axon growth in response to myelin. Transcriptomic screens of rodent NPCs identified the cell adhesion molecule neuronal growth regulator 1 (Negr1) as one mediator of permissive axon-myelin interactions. The stimulatory effect of myelin-associated proteins on rodent NPCs was developmentally regulated and involved direct activation of the extracellular signal-regulated kinase (ERK). The stimulatory effects of myelin on NPC/NSC axon outgrowth should be investigated further and could potentially be exploited for neural repair after SCI.
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Affiliation(s)
- Gunnar H D Poplawski
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Richard Lie
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Matt Hunt
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Hiromi Kumamaru
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Riki Kawaguchi
- Departments of Psychiatry and Neurology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Paul Lu
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
- Veterans Administration Medical Center, San Diego, CA 92161, USA
| | - Michael K E Schäfer
- Department of Anesthesiology and Focus Program Translational Neurosciences, Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| | - Grace Woodruff
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jacob Robinson
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Philip Canete
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jennifer N Dulin
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Cedric G Geoffroy
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Lutz Menzel
- Department of Anesthesiology and Focus Program Translational Neurosciences, Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| | - Binhai Zheng
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Giovanni Coppola
- Departments of Psychiatry and Neurology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Mark H Tuszynski
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA.
- Veterans Administration Medical Center, San Diego, CA 92161, USA
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7
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Wang S, Chen X, Wu W, Chen Z, Du H, Wang X, Fu YV, Hu L, Chen J. Rapid, label-free identification of cerebellar structures using multiphoton microscopy. J Biophotonics 2017; 10:1617-1626. [PMID: 28464515 DOI: 10.1002/jbio.201600297] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 03/10/2017] [Accepted: 03/21/2017] [Indexed: 05/22/2023]
Abstract
The cerebellum is the prominent laminar structure of the mammalian brain that has been implicated in various psychiatric and neurological diseases. Although clinical brain imaging techniques have provided precise anatomic images of cerebellar structures, a definitive diagnosis still requires adequate resolution to identify individual layers in cerebellar cortex, the extent of tumor, even requires the histological tissue examination during surgical procedures. In this study, multiphoton microscopy (MPM), based on second harmonic generation (SHG) and two-photon excited fluorescence (TPEF), was perform on the rat cerebellar structures and pathology with the combination of image analysis methods. Results show that MPM can reveal the cerebellar vermis, hemispheres, medulla, and ventricle, as well as axon bundles, Purkinje cells, capillaries, and the pia mater of the cerebellum. Together with custom-developed image processing algorithms, MPM could further differentiate between the gray and white matter, as well as evaluate the Purkinje cell layer, identify the cerebellar tumor boundary, and distinguish between the tumor core and peritumor regions. Our results establish a direct visualization and rapid assessment approach for the cerebellar structures, as well as suggest the feasibility of in vivo multiphoton microendoscopes and fiberscopes as clinical tools for neuropathological diagnoses.
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Affiliation(s)
- Shu Wang
- Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory of Photonics Technology, Fujian Normal University, Fuzhou, 350007, P. R. China
| | - Xiuqiang Chen
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, P. R. China
| | - Weilin Wu
- Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory of Photonics Technology, Fujian Normal University, Fuzhou, 350007, P. R. China
| | - Zhida Chen
- Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory of Photonics Technology, Fujian Normal University, Fuzhou, 350007, P. R. China
| | - Huiping Du
- Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory of Photonics Technology, Fujian Normal University, Fuzhou, 350007, P. R. China
| | - Xingfu Wang
- Department of Pathology, The First Affiliated Hospital, Fujian Medical University, Fuzhou, 350004, P. R. China
| | - Yu Vincent Fu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, P. R. China
| | - Liwen Hu
- Department of Pathology, The First Affiliated Hospital, Fujian Medical University, Fuzhou, 350004, P. R. China
| | - Jianxin Chen
- Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory of Photonics Technology, Fujian Normal University, Fuzhou, 350007, P. R. China
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8
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Wang S, Chen X, Wu W, Chen Z, Du H, Wang X, Fu YV, Hu L, Chen J. Rapid, label-free identification of cerebellar structures using multiphoton microscopy. J Biophotonics 2017; 10:1617-1626. [PMID: 28464515 DOI: 10.1002/jbio.v10.12] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 03/10/2017] [Accepted: 03/21/2017] [Indexed: 05/25/2023]
Abstract
The cerebellum is the prominent laminar structure of the mammalian brain that has been implicated in various psychiatric and neurological diseases. Although clinical brain imaging techniques have provided precise anatomic images of cerebellar structures, a definitive diagnosis still requires adequate resolution to identify individual layers in cerebellar cortex, the extent of tumor, even requires the histological tissue examination during surgical procedures. In this study, multiphoton microscopy (MPM), based on second harmonic generation (SHG) and two-photon excited fluorescence (TPEF), was perform on the rat cerebellar structures and pathology with the combination of image analysis methods. Results show that MPM can reveal the cerebellar vermis, hemispheres, medulla, and ventricle, as well as axon bundles, Purkinje cells, capillaries, and the pia mater of the cerebellum. Together with custom-developed image processing algorithms, MPM could further differentiate between the gray and white matter, as well as evaluate the Purkinje cell layer, identify the cerebellar tumor boundary, and distinguish between the tumor core and peritumor regions. Our results establish a direct visualization and rapid assessment approach for the cerebellar structures, as well as suggest the feasibility of in vivo multiphoton microendoscopes and fiberscopes as clinical tools for neuropathological diagnoses.
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Affiliation(s)
- Shu Wang
- Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory of Photonics Technology, Fujian Normal University, Fuzhou, 350007, P. R. China
| | - Xiuqiang Chen
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, P. R. China
| | - Weilin Wu
- Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory of Photonics Technology, Fujian Normal University, Fuzhou, 350007, P. R. China
| | - Zhida Chen
- Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory of Photonics Technology, Fujian Normal University, Fuzhou, 350007, P. R. China
| | - Huiping Du
- Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory of Photonics Technology, Fujian Normal University, Fuzhou, 350007, P. R. China
| | - Xingfu Wang
- Department of Pathology, The First Affiliated Hospital, Fujian Medical University, Fuzhou, 350004, P. R. China
| | - Yu Vincent Fu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, P. R. China
| | - Liwen Hu
- Department of Pathology, The First Affiliated Hospital, Fujian Medical University, Fuzhou, 350004, P. R. China
| | - Jianxin Chen
- Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory of Photonics Technology, Fujian Normal University, Fuzhou, 350007, P. R. China
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9
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Heise V, Zsoldos E, Suri S, Sexton C, Topiwala A, Filippini N, Mahmood A, Allan CL, Singh-Manoux A, Kivimäki M, Mackay CE, Ebmeier KP. Uncoupling protein 2 haplotype does not affect human brain structure and function in a sample of community-dwelling older adults. PLoS One 2017; 12:e0181392. [PMID: 28771482 PMCID: PMC5542610 DOI: 10.1371/journal.pone.0181392] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 06/21/2017] [Indexed: 11/19/2022] Open
Abstract
Uncoupling protein 2 (UCP2) is a mitochondrial membrane protein that plays a role in uncoupling electron transport from adenosine triphosphate (ATP) formation. Polymorphisms of the UCP2 gene in humans affect protein expression and function and have been linked to survival into old age. Since UCP2 is expressed in several brain regions, we investigated in this study whether UCP2 polymorphisms might 1) affect occurrence of neurodegenerative or mental health disorders and 2) affect measures of brain structure and function. We used structural magnetic resonance imaging (MRI), diffusion-weighted MRI and resting-state functional MRI in the neuroimaging sub-study of the Whitehall II cohort. Data from 536 individuals aged 60 to 83 years were analyzed. No association of UCP2 polymorphisms with the occurrence of neurodegenerative disorders or grey and white matter structure or resting-state functional connectivity was observed. However, there was a significant effect on occurrence of mood disorders in men with the minor alleles of -866G>A (rs659366) and Ala55Val (rs660339)) being associated with increasing odds of lifetime occurrence of mood disorders in a dose dependent manner. This result was not accompanied by effects of UCP2 polymorphisms on brain structure and function, which might either indicate that the sample investigated here was too small and underpowered to find any significant effects, or that potential effects of UCP2 polymorphisms on the brain are too subtle to be picked up by any of the neuroimaging measures used.
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Affiliation(s)
- Verena Heise
- OHBA, Oxford Centre for Human Brain Activity, University of Oxford, Oxford, United Kingdom
- Department of Psychiatry, University of Oxford, Oxford, United Kingdom
- Nuffield Department of Population Health, University of Oxford, Oxford, United Kingdom
- * E-mail:
| | - Enikő Zsoldos
- Department of Psychiatry, University of Oxford, Oxford, United Kingdom
| | - Sana Suri
- OHBA, Oxford Centre for Human Brain Activity, University of Oxford, Oxford, United Kingdom
- Department of Psychiatry, University of Oxford, Oxford, United Kingdom
| | - Claire Sexton
- OHBA, Oxford Centre for Human Brain Activity, University of Oxford, Oxford, United Kingdom
- Department of Psychiatry, University of Oxford, Oxford, United Kingdom
| | - Anya Topiwala
- Department of Psychiatry, University of Oxford, Oxford, United Kingdom
| | - Nicola Filippini
- Department of Psychiatry, University of Oxford, Oxford, United Kingdom
| | - Abda Mahmood
- Department of Psychiatry, University of Oxford, Oxford, United Kingdom
| | - Charlotte L. Allan
- Department of Psychiatry, University of Oxford, Oxford, United Kingdom
- Northumberland, Tyne and Wear NHS Foundation Trust and Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Archana Singh-Manoux
- Department of Epidemiology and Public Health, University College London, London, United Kingdom
- Centre for Research in Epidemiology and Population Health, Hôpital Paul Brousse, INSERM, U1018, Villejuif, France
| | - Mika Kivimäki
- Department of Epidemiology and Public Health, University College London, London, United Kingdom
| | - Clare E. Mackay
- OHBA, Oxford Centre for Human Brain Activity, University of Oxford, Oxford, United Kingdom
- Department of Psychiatry, University of Oxford, Oxford, United Kingdom
| | - Klaus P. Ebmeier
- Department of Psychiatry, University of Oxford, Oxford, United Kingdom
- Oxford Health NHS Foundation Trust, Warneford Hospital, Oxford, United Kingdom
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10
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Broad KD, Hassell J, Fleiss B, Kawano G, Ezzati M, Rocha-Ferreira E, Hristova M, Bennett K, Fierens I, Burnett R, Chaban B, Alonso-Alconada D, Oliver-Taylor A, Tachsidis I, Rostami J, Gressens P, Sanders RD, Robertson NJ. Isoflurane Exposure Induces Cell Death, Microglial Activation and Modifies the Expression of Genes Supporting Neurodevelopment and Cognitive Function in the Male Newborn Piglet Brain. PLoS One 2016; 11:e0166784. [PMID: 27898690 PMCID: PMC5127656 DOI: 10.1371/journal.pone.0166784] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 11/03/2016] [Indexed: 12/02/2022] Open
Abstract
Exposure of the brain to general anesthesia during early infancy may adversely affect its neural and cognitive development. The mechanisms mediating this are complex, incompletely understood and may be sexually dimorphic, but include developmentally inappropriate apoptosis, inflammation and a disruption to cognitively salient gene expression. We investigated the effects of a 6h isoflurane exposure on cell death, microglial activation and gene expression in the male neonatal piglet brain. Piglets (n = 6) were randomised to: (i) naive controls or (ii) 6h isoflurane. Cell death (TUNEL and caspase-3) and microglial activation were recorded in 7 brain regions. Changes in gene expression (microarray and qPCR) were assessed in the cingulate cortex. Electroencephalography (EEG) was recorded throughout. Isoflurane anesthesia induced significant increases in cell death in the cingulate and insular cortices, caudate nucleus, thalamus, putamen, internal capsule, periventricular white matter and hippocampus. Dying cells included both neurons and oligodendrocytes. Significantly, microglial activation was observed in the insula, pyriform, hippocampus, internal capsule, caudate and thalamus. Isoflurane induced significant disruption to the expression of 79 gene transcripts, of these 26 are important for the control of transcription and 23 are important for the mediation of neural plasticity, memory formation and recall. Our observations confirm that isoflurane increases apoptosis and inflammatory responses in the neonatal piglet brain but also suggests novel additional mechanisms by which isoflurane may induce adverse neural and cognitive development by disrupting the expression of genes mediating activity dependent development of neural circuits, the predictive adaptive responses of the brain, memory formation and recall.
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Affiliation(s)
- Kevin D. Broad
- Institute for Women’s Health, University College London, London, United Kingdom
| | - Jane Hassell
- Institute for Women’s Health, University College London, London, United Kingdom
| | - Bobbi Fleiss
- Centre for the Developing Brain, Kings College, St Thomas’s Campus, London, United Kingdom
- Inserm, Paris, France
- University Paris Diderot, Sorbonne Paris Cite, Paris, France
| | - Go Kawano
- Institute for Women’s Health, University College London, London, United Kingdom
| | - Mojgan Ezzati
- Institute for Women’s Health, University College London, London, United Kingdom
| | | | - Mariya Hristova
- Institute for Women’s Health, University College London, London, United Kingdom
| | - Kate Bennett
- Institute for Women’s Health, University College London, London, United Kingdom
| | - Igor Fierens
- Institute for Women’s Health, University College London, London, United Kingdom
| | - Ryan Burnett
- Institute for Women’s Health, University College London, London, United Kingdom
| | - Badr Chaban
- Institute for Women’s Health, University College London, London, United Kingdom
| | | | - Aaron Oliver-Taylor
- Institute for Women’s Health, University College London, London, United Kingdom
| | - Ilias Tachsidis
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Jamshid Rostami
- Institute for Women’s Health, University College London, London, United Kingdom
| | - Pierre Gressens
- Centre for the Developing Brain, Kings College, St Thomas’s Campus, London, United Kingdom
- Inserm, Paris, France
- University Paris Diderot, Sorbonne Paris Cite, Paris, France
| | - Robert D. Sanders
- Department of Anesthesiology, University of Wisconsin, Madison, United States of America
- Wellcome Department of Imaging Neuroscience, University College London, London, United Kingdom
- Surgical Outcomes Research Centre, University College London Hospital, London, United Kingdom
| | - Nicola J. Robertson
- Institute for Women’s Health, University College London, London, United Kingdom
- * E-mail:
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11
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Robillard KN, Lee KM, Chiu KB, MacLean AG. Glial cell morphological and density changes through the lifespan of rhesus macaques. Brain Behav Immun 2016; 55:60-69. [PMID: 26851132 PMCID: PMC4899176 DOI: 10.1016/j.bbi.2016.01.006] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 01/04/2016] [Accepted: 01/12/2016] [Indexed: 11/18/2022] Open
Abstract
How aging impacts the central nervous system (CNS) is an area of intense interest. Glial morphology is known to affect neuronal and immune function as well as metabolic and homeostatic balance. Activation of glia, both astrocytes and microglia, occurs at several stages during development and aging. The present study analyzed changes in glial morphology and density through the entire lifespan of rhesus macaques, which are physiologically and anatomically similar to humans. We observed apparent increases in gray matter astrocytic process length and process complexity as rhesus macaques matured from juveniles through adulthood. These changes were not attributed to cell enlargement because they were not accompanied by proportional changes in soma or process volume. There was a decrease in white matter microglial process length as rhesus macaques aged. Aging was shown to have a significant effect on gray matter microglial density, with a significant increase in aged macaques compared with adults. Overall, we observed significant changes in glial morphology as macaques age indicative of astrocytic activation with subsequent increase in microglial density in aged macaques.
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Affiliation(s)
- Katelyn N Robillard
- Tulane National Primate Research Center, Covington, LA, United States; Southeastern Louisiana University, Hammond, LA, United States
| | - Kim M Lee
- Tulane National Primate Research Center, Covington, LA, United States; Tulane Program in Biomedical Sciences, Tulane University School of Medicine, New Orleans, LA, United States
| | - Kevin B Chiu
- Tulane National Primate Research Center, Covington, LA, United States
| | - Andrew G MacLean
- Tulane National Primate Research Center, Covington, LA, United States; Tulane Program in Biomedical Sciences, Tulane University School of Medicine, New Orleans, LA, United States; Tulane Program in Neuroscience, Tulane University, New Orleans, LA, United States; Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, LA, United States.
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12
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Kottke R, Pichler Hefti J, Rummel C, Hauf M, Hefti U, Merz TM. Morphological Brain Changes after Climbing to Extreme Altitudes--A Prospective Cohort Study. PLoS One 2015; 10:e0141097. [PMID: 26509635 PMCID: PMC4625036 DOI: 10.1371/journal.pone.0141097] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 10/05/2015] [Indexed: 11/19/2022] Open
Abstract
Background Findings of cerebral cortical atrophy, white matter lesions and microhemorrhages have been reported in high-altitude climbers. The aim of this study was to evaluate structural cerebral changes in a large cohort of climbers after an ascent to extreme altitudes and to correlate these findings with the severity of hypoxia and neurological signs during the climb. Methods Magnetic resonance imaging (MRI) studies were performed in 38 mountaineers before and after participating in a high altitude (7126m) climbing expedition. The imaging studies were assessed for occurrence of new WM hyperintensities and microhemorrhages. Changes of partial volume estimates of cerebrospinal fluid, grey matter, and white matter were evaluated by voxel-based morphometry. Arterial oxygen saturation and acute mountain sickness scores were recorded daily during the climb. Results On post-expedition imaging no new white matter hyperintensities were observed. Compared to baseline testing, we observed a significant cerebrospinal fluid fraction increase (0.34% [95% CI 0.10–0.58], p = 0.006) and a white matter fraction reduction (-0.18% [95% CI -0.32–-0.04], p = 0.012), whereas the grey matter fraction remained stable (0.16% [95% CI -0.46–0.13], p = 0.278). Post-expedition imaging revealed new microhemorrhages in 3 of 15 climbers reaching an altitude of over 7000m. Affected climbers had significantly lower oxygen saturation values but not higher acute mountain sickness scores than climbers without microhemorrhages. Conclusions A single sojourn to extreme altitudes is not associated with development of focal white matter hyperintensities and grey matter atrophy but leads to a decrease in brain white matter fraction. Microhemorrhages indicative of substantial blood-brain barrier disruption occur in a significant number of climbers attaining extreme altitudes.
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Affiliation(s)
- Raimund Kottke
- Institute for Diagnostic and Interventional Neuroradiology, University Hospital and University of Bern, 3010, Bern, Switzerland
| | - Jacqueline Pichler Hefti
- Department of Intensive Care Medicine, University Hospital and University of Bern, 3010, Bern, Switzerland
| | - Christian Rummel
- Support Centre for Advanced Neuroimaging (SCAN), Institute for Diagnostic and Interventional Neuroradiology, University Hospital and University of Bern, 3010, Bern, Switzerland
| | - Martinus Hauf
- Institute for Diagnostic and Interventional Neuroradiology, University Hospital and University of Bern, 3010, Bern, Switzerland
| | - Urs Hefti
- Swiss Sport Clinic, 3014, Bern, Switzerland
| | - Tobias Michael Merz
- Department of Intensive Care Medicine, University Hospital and University of Bern, 3010, Bern, Switzerland
- * E-mail:
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13
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Shimizu Y, Sakai KL. [Visualization of Gray Matter Myelin and Fiber Bundles Critical for Relative Pitch: A Role of the Left Posterior Long Insular Cortex]. Brain Nerve 2015; 67:1147-1155. [PMID: 26329156 DOI: 10.11477/mf.1416200274] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Relative pitch is the ability to identify a tone pitch based on external or internal pitches. Here we used magnetic resonance imaging (MRI) to determine which cortical region is responsible for relative pitch. Forty-eight participants were asked to listen to 24 piano tones, and then write down the names of the tones (except reference tones of a(1)=440 Hz, which were intermittently presented three times). We classified the participants into three groups based on their task scores: Group A (n=12, full points), Group B (n=22, 6-20 points), and Group C (n=14, 0-5 points). We focused on the myelin of the gray matter, which can be visualized by the ratio of MR signals from a pair of T(1)- and T(2)-weighted images. We found significantly increased ratios in the left posterior long insular cortex for Group A. We also observed more consistent pathways in the anterior region of the left middle longitudinal fasciculus for Group A compared to Group C, which passed through the left superior temporal gyrus. Because these regions are involved in the processing of speech sounds, the present results suggest that the ability to identify musical pitches is associated with universal linguistic abilities.
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Affiliation(s)
- Yuichiro Shimizu
- Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo
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14
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Miyazaki M, Ouyang C, Zhou X, Murdoch JB, Fushimi Y, Okada T, Fujimoto K, Kido A, Arakawa Y, Miyamoto S, Togashi K. Z-Spectrum analysis provides proton environment data (ZAPPED): a new two-pool technique for human gray and white matter. PLoS One 2015; 10:e0119915. [PMID: 25768108 PMCID: PMC4358893 DOI: 10.1371/journal.pone.0119915] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 01/18/2015] [Indexed: 11/19/2022] Open
Abstract
A new technique - Z-spectrum Analysis Provides Proton Environment Data (ZAPPED) - was used to map cross-relaxing free and restricted protons in nine healthy subjects plus two brain tumor patients at 3T. First, MT data were acquired over a wide symmetric range of frequency offsets, and then a trio of quantitative biomarkers, i.e., the apparent spin-spin relaxation times (T2,f, T2,r) in both free and restricted proton pools as well as the restricted pool fraction Fr, were mapped by fitting the measured Z-spectra to a simple two-Lorentzian compartment model on a voxel-by-voxel basis. The mean restricted exchangeable proton fraction, Fr, was found to be 0.17 in gray matter (GM) and 0.28 in white matter (WM) in healthy subjects. Corresponding mean values for apparent spin-spin relaxation times were 785 µs (T2,f) and 17.7 µs (T2,r) in GM, 672 µs (T2,f) and 23.4 µs (T2,r) in WM. The percentages of Ff and Fr in GM are similar for all ages, whereas Fr shows a tendency to decrease with age in WM among healthy subjects. The patient ZAPPED images show higher contrast between tumor and normal tissues than traditional T2-weighted and T1-weighted images. The ZAPPED method provides a simple phenomenological approach to estimating fractions and apparent T2 values of free and restricted MT-active protons, and it may offer clinical useful information.
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Affiliation(s)
- Mitsue Miyazaki
- MR Research, Toshiba Medical Research Institute, Vernon Hills, Illinois, United States of America
- * E-mail:
| | - Cheng Ouyang
- MR Research, Toshiba Medical Research Institute, Vernon Hills, Illinois, United States of America
| | - Xiangzhi Zhou
- MR Research, Toshiba Medical Research Institute, Vernon Hills, Illinois, United States of America
| | - James B. Murdoch
- MR Research, Toshiba Medical Research Institute, Vernon Hills, Illinois, United States of America
| | - Yasutaka Fushimi
- Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Tomohisa Okada
- Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Koji Fujimoto
- Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Aki Kido
- Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Yoshiki Arakawa
- Department of Neurosurgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Susumu Miyamoto
- Department of Neurosurgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Kaori Togashi
- Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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15
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Dibb R, Li W, Cofer G, Liu C. Microstructural origins of gadolinium-enhanced susceptibility contrast and anisotropy. Magn Reson Med 2014; 72:1702-11. [PMID: 24443202 PMCID: PMC4102673 DOI: 10.1002/mrm.25082] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Revised: 11/21/2013] [Accepted: 11/25/2013] [Indexed: 01/20/2023]
Abstract
PURPOSE MR histology based on magnetic susceptibility can be used to visualize diamagnetic myelin (and its deterioration) in the central nervous system and is facilitated by the application of high magnetic field strengths and paramagnetic contrast agents. Characterizing the effect of these tools will aid in assessing white matter myelin content and microstructure. METHODS Image data from six gadolinium-perfused mouse brain specimens were acquired at 2.0, 7.0, and 9.4 Tesla. Magnetic susceptibility contrast was analyzed for its dependence on field strength, gadolinium concentration, and white matter fiber orientation. A model for this contrast is presented based on the three-pool model for white matter. RESULTS The specimen data illustrate that white-gray matter susceptibility contrast is field strength independent. White-gray matter contrast improves significantly as a function of gadolinium contrast agent in the tissue, i.e., white matter appears increasingly more diamagnetic relative to gray matter. The simulated data from the model suggest that susceptibility anisotropy of white matter fiber bundles increases nonlinearly as a function of gadolinium concentration due to contrast agent compartmentalization into the extracellular white matter water pool. CONCLUSION Using contrast agents in MR histology facilitates white-gray matter susceptibility contrast modulation and the probing of white matter microstructure and orientation.
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Affiliation(s)
- Russell Dibb
- Center for In Vivo Microscopy, Duke University Medical Center, Durham, NC, USA
- Biomedical Engineering, Duke University, Durham, NC, USA
| | - Wei Li
- Brain Imaging & Analysis Center, Duke University Medical Center, Durham, NC, USA
| | - Gary Cofer
- Center for In Vivo Microscopy, Duke University Medical Center, Durham, NC, USA
| | - Chunlei Liu
- Brain Imaging & Analysis Center, Duke University Medical Center, Durham, NC, USA
- Radiology, Duke University Medical Center, Durham, NC, USA
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16
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Your brain on media multi-tasking. Can Nurse 2014; 110:8. [PMID: 25536691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
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17
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Sampaio-Baptista C, Scholz J, Jenkinson M, Thomas AG, Filippini N, Smit G, Douaud G, Johansen-Berg H. Gray matter volume is associated with rate of subsequent skill learning after a long term training intervention. Neuroimage 2014; 96:158-66. [PMID: 24680712 PMCID: PMC4075341 DOI: 10.1016/j.neuroimage.2014.03.056] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 02/27/2014] [Accepted: 03/20/2014] [Indexed: 11/18/2022] Open
Abstract
The ability to predict learning performance from brain imaging data has implications for selecting individuals for training or rehabilitation interventions. Here, we used structural MRI to test whether baseline variations in gray matter (GM) volume correlated with subsequent performance after a long-term training of a complex whole-body task. 44 naïve participants were scanned before undertaking daily juggling practice for 6 weeks, following either a high intensity or a low intensity training regime. To assess performance across the training period participants' practice sessions were filmed. Greater GM volume in medial occipito-parietal areas at baseline correlated with steeper learning slopes. We also tested whether practice time or performance outcomes modulated the degree of structural brain change detected between the baseline scan and additional scans performed immediately after training and following a further 4 weeks without training. Participants with better performance had higher increases in GM volume during the period following training (i.e., between scans 2 and 3) in dorsal parietal cortex and M1. When contrasting brain changes between the practice intensity groups, we did not find any straightforward effects of practice time though practice modulated the relationship between performance and GM volume change in dorsolateral prefrontal cortex. These results suggest that practice time and performance modulate the degree of structural brain change evoked by long-term training regimes. Inter-individual differences in brain structure correlate with subsequent performance outcome. Performance outcome plays an important role in positive structural brain change. Performance outcome and amount of practice modulate structural brain change.
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Affiliation(s)
- Cassandra Sampaio-Baptista
- Oxford Centre for Functional MRI of the Brain (FMRIB), Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DU, UK
| | - Jan Scholz
- Oxford Centre for Functional MRI of the Brain (FMRIB), Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DU, UK; Mouse Imaging Centre, Hospital for Sick Children, 25 Orde Street, Toronto, Ontario M5T 3H7, Canada
| | - Mark Jenkinson
- Oxford Centre for Functional MRI of the Brain (FMRIB), Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DU, UK
| | - Adam G Thomas
- Oxford Centre for Functional MRI of the Brain (FMRIB), Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DU, UK; NIMH, National Institutes of Health, Bethesda, MD 20892-1148, USA
| | - Nicola Filippini
- Oxford Centre for Functional MRI of the Brain (FMRIB), Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DU, UK; Department of Psychiatry, University of Oxford, Warneford Hospital, OX3 7JX UK
| | - Gabrielle Smit
- Oxford Centre for Functional MRI of the Brain (FMRIB), Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DU, UK
| | - Gwenaëlle Douaud
- Oxford Centre for Functional MRI of the Brain (FMRIB), Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DU, UK
| | - Heidi Johansen-Berg
- Oxford Centre for Functional MRI of the Brain (FMRIB), Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DU, UK.
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18
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Truong TK, Guidon A, Song AW. Cortical depth dependence of the diffusion anisotropy in the human cortical gray matter in vivo. PLoS One 2014; 9:e91424. [PMID: 24608869 PMCID: PMC3946789 DOI: 10.1371/journal.pone.0091424] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 02/11/2014] [Indexed: 11/21/2022] Open
Abstract
Diffusion tensor imaging (DTI) is typically used to study white matter fiber pathways, but may also be valuable to assess the microstructure of cortical gray matter. Although cortical diffusion anisotropy has previously been observed in vivo, its cortical depth dependence has mostly been examined in high-resolution ex vivo studies. This study thus aims to investigate the cortical depth dependence of the diffusion anisotropy in the human cortex in vivo on a clinical 3 T scanner. Specifically, a novel multishot constant-density spiral DTI technique with inherent correction of motion-induced phase errors was used to achieve a high spatial resolution (0.625×0.625×3 mm) and high spatial fidelity with no scan time penalty. The results show: (i) a diffusion anisotropy in the cortical gray matter, with a primarily radial diffusion orientation, as observed in previous ex vivo and in vivo studies, and (ii) a cortical depth dependence of the fractional anisotropy, with consistently higher values in the middle cortical lamina than in the deep and superficial cortical laminae, as observed in previous ex vivo studies. These results, which are consistent across subjects, demonstrate the feasibility of this technique for investigating the cortical depth dependence of the diffusion anisotropy in the human cortex in vivo.
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Affiliation(s)
- Trong-Kha Truong
- Brain Imaging and Analysis Center, Duke University, Durham, North Carolina, United States of America
- * E-mail:
| | - Arnaud Guidon
- Brain Imaging and Analysis Center, Duke University, Durham, North Carolina, United States of America
| | - Allen W. Song
- Brain Imaging and Analysis Center, Duke University, Durham, North Carolina, United States of America
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Abstract
Myelination by oligodendrocytes is a highly specialized process that relies on intimate interactions between the axon and the oligodendrocytes. Astrocytes have an important part in facilitating myelination in the CNS, however, comparatively less is known about how they affect myelination. This review therefore summarizes the literature and explores lingering questions surrounding differences between white matter and gray matter astrocytes, how astrocytes support myelination, how their dysfunction in pathological states contributes to myelin pathologies and how astrocytes may facilitate remyelination. We discuss how astrocytes in the white matter are specialized to promote myelination and myelin maintenance by clearance of extracellular ions and neurotransmitters and by secretion of pro-myelinating factors. Additionally, astrocyte-oligodendrocyte coupling via gap junctions is crucial for both myelin formation and maintenance, due to K(+) buffering and possibly metabolic support for oligodendrocytes via the panglial syncytium. Dysfunctional astrocytes aberrantly affect oligodendrocytes, as exemplified by a number of leukodystrophies in which astrocytic pathology is known as the direct cause of myelin pathology. Conversely, in primary demyelinating diseases, such as multiple sclerosis, astrocytes may facilitate remyelination. We suggest that specific manipulation of astrocytes could help prevent myelin pathologies and successfully restore myelin sheaths after demyelination.
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Affiliation(s)
- I Lundgaard
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY 14642, USA.
| | - M J Osório
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - B T Kress
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - S Sanggaard
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - M Nedergaard
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY 14642, USA
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