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McKenzie AT, Nnadi O, Slagell KD, Thorn EL, Farrell K, Crary JF. Fluid preservation in brain banking: a review. FREE NEUROPATHOLOGY 2024; 5:5-10. [PMID: 38690035 PMCID: PMC11058410 DOI: 10.17879/freeneuropathology-2024-5373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Accepted: 03/29/2024] [Indexed: 05/02/2024]
Abstract
Fluid preservation is nearly universally used in brain banking to store fixed tissue specimens for future research applications. However, the effects of long-term immersion on neural circuitry and biomolecules are not well characterized. As a result, there is a need to synthesize studies investigating fluid preservation of brain tissue. We searched PubMed and other databases to identify studies measuring the effects of fluid preservation in nervous system tissue. We categorized studies based on the fluid preservative used: formaldehyde solutions, buffer solutions, alcohol solutions, storage after tissue clearing, and cryoprotectant solutions. We identified 91 studies containing 197 independent observations of the effects of long-term storage on cellular morphology. Most studies did not report any significant alterations due to long-term storage. When present, the most frequent alteration was decreased antigenicity, commonly attributed to progressive crosslinking by aldehydes that renders biomolecules increasingly inaccessible over time. To build a mechanistic understanding, we discuss biochemical aspects of long-term fluid preservation. A subset of lipids appears to be chemical altered or extracted over time due to incomplete retention in the crosslinked gel. Alternative storage fluids mitigate the problem of antigen masking but have not been extensively characterized and may have other downsides. We also compare fluid preservation to cryopreservation, paraffin embedding, and resin embedding. Overall, existing evidence suggests that fluid preservation provides maintenance of neural architecture for decades, including precise structural details. However, to avoid the well-established problem of overfixation caused by storage in high concentration formaldehyde solutions, fluid preservation procedures can use an initial fixation step followed by an alternative long-term storage fluid. Further research is warranted on optimizing protocols and characterizing the generalizability of the storage artifacts that have been identified.
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Affiliation(s)
| | - Oge Nnadi
- Brain Preservation Foundation, Ashburn, Virginia, USA
| | - Kat D. Slagell
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Friedman Brain Institute, Departments of Pathology, Neuroscience, and Artificial Intelligence & Human Health, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Neuropathology Brain Bank & Research Core and Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Emma L. Thorn
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Friedman Brain Institute, Departments of Pathology, Neuroscience, and Artificial Intelligence & Human Health, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Neuropathology Brain Bank & Research Core and Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Kurt Farrell
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Friedman Brain Institute, Departments of Pathology, Neuroscience, and Artificial Intelligence & Human Health, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Neuropathology Brain Bank & Research Core and Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - John F. Crary
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Friedman Brain Institute, Departments of Pathology, Neuroscience, and Artificial Intelligence & Human Health, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Neuropathology Brain Bank & Research Core and Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, New York, USA
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Bernardini A, Trovatelli M, Kłosowski MM, Pederzani M, Zani DD, Brizzola S, Porter A, Rodriguez Y Baena F, Dini D. Reconstruction of ovine axonal cytoarchitecture enables more accurate models of brain biomechanics. Commun Biol 2022; 5:1101. [PMID: 36253409 PMCID: PMC9576772 DOI: 10.1038/s42003-022-04052-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 09/29/2022] [Indexed: 12/03/2022] Open
Abstract
There is an increased need and focus to understand how local brain microstructure affects the transport of drug molecules directly administered to the brain tissue, for example in convection-enhanced delivery procedures. This study reports a systematic attempt to characterize the cytoarchitecture of commissural, long association and projection fibres, namely the corpus callosum, the fornix and the corona radiata, with the specific aim to map different regions of the tissue and provide essential information for the development of accurate models of brain biomechanics. Ovine samples are imaged using scanning electron microscopy combined with focused ion beam milling to generate 3D volume reconstructions of the tissue at subcellular spatial resolution. Focus is placed on the characteristic cytological feature of the white matter: the axons and their alignment in the tissue. For each tract, a 3D reconstruction of relatively large volumes, including a significant number of axons, is performed and outer axonal ellipticity, outer axonal cross-sectional area and their relative perimeter are measured. The study of well-resolved microstructural features provides useful insight into the fibrous organization of the tissue, whose micromechanical behaviour is that of a composite material presenting elliptical tortuous tubular axonal structures embedded in the extra-cellular matrix. Drug flow can be captured through microstructurally-based models using 3D volumes, either reconstructed directly from images or generated in silico using parameters extracted from the database of images, leading to a workflow to enable physically-accurate simulations of drug delivery to the targeted tissue. Imaging and reconstruction of sheep brain axonal cytoarchitecture provides insight for brain biomechanics models that simulate drug delivery and other biological processes governed by interstitial fluid flow and transport.
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Affiliation(s)
- Andrea Bernardini
- Department of Mechanical Engineering, Imperial College London, London, SW7 2AZ, UK.
| | - Marco Trovatelli
- Faculty of Veterinary Medicine, Università degli Studi di Milano Statale, 26900, Lodi, Italy
| | | | - Matteo Pederzani
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, 20133, Milan, Italy
| | - Davide Danilo Zani
- Faculty of Veterinary Medicine, Università degli Studi di Milano Statale, 26900, Lodi, Italy
| | - Stefano Brizzola
- Faculty of Veterinary Medicine, Università degli Studi di Milano Statale, 26900, Lodi, Italy
| | - Alexandra Porter
- Department of Materials, Imperial College London, London, SW7 2AZ, UK
| | | | - Daniele Dini
- Department of Mechanical Engineering, Imperial College London, London, SW7 2AZ, UK.
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3
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Liu Y, Wang Z, Cao C, Xu Z, Lu J, Shen H, Li X, Li H, Wu J, Chen G. Aquaporin 4 Depolarization-Enhanced Transferrin Infiltration Leads to Neuronal Ferroptosis after Subarachnoid Hemorrhage in Mice. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:8808677. [PMID: 35761873 PMCID: PMC9233479 DOI: 10.1155/2022/8808677] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 05/30/2022] [Accepted: 06/03/2022] [Indexed: 12/19/2022]
Abstract
The infiltration of blood components into the brain parenchyma through the lymphoid system is an important cause of subarachnoid hemorrhage injury. AQP4, a water channel protein located at the astrocyte foot, has been reported to regulate blood-brain barrier integrity, and its polarization is disrupted after SAH. Neuronal ferroptosis is involved in subarachnoid hemorrhage- (SAH-) induced brain injury, but the inducing factors are not completely clear. Transferrin is one of the inducing factors of ferroptosis. This study is aimed at researching the role and mechanism of AQP4 in brain injury after subarachnoid hemorrhage in mice. An experimental mouse SAH model was established by endovascular perforation. An AAV vector encoding AQP4 with a GFAP-specific promoter was administered to mice to achieve specific overexpression of AQP4 in astrocytes. PI staining, Fer-1 intervention, and transmission electron microscopy were used to detect neuronal ferroptosis, and dextran (40 kD) leakage was used to detect BBB integrity. Western blot analysis of perfused brain tissue protein samples was used to detect transferrin infiltration. First, neuronal ferroptosis 24 h after SAH was observed by PI staining and Fer-1 intervention. Second, a significant increase in transferrin infiltration was found in the brain parenchyma 24 h after SAH modeling, while transferrin content was positively correlated with neuronal ferroptosis. Then, we observed that AQP4 overexpression effectively improved AQP depolarization and BBB injury induced by SAH and significantly reduced transferrin infiltration and neuronal ferroptosis after SAH. Finally, we found that AQP4 overexpression could effectively improve the neurobehavioral ability of SAH mice, and the neurobehavioral ability was negatively correlated with transferrin brain content. Taken together, these data indicate that overexpression of AQP4 in the mouse brain can effectively improve post-SAH neuronal ferroptosis and brain injury, at least partly by inhibiting transferrin infiltration into the brain parenchyma in the glymphatic system.
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Affiliation(s)
- Yuan Liu
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, 188 Shizi Street Suzhou Jiangsu Province 215006, China
- Institute of Stroke Research, Soochow University, China
| | - Zongqi Wang
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, 188 Shizi Street Suzhou Jiangsu Province 215006, China
- Institute of Stroke Research, Soochow University, China
| | - Chang Cao
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, 188 Shizi Street Suzhou Jiangsu Province 215006, China
- Institute of Stroke Research, Soochow University, China
| | - Zhongmou Xu
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, 188 Shizi Street Suzhou Jiangsu Province 215006, China
- Institute of Stroke Research, Soochow University, China
| | - Jinxin Lu
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, 188 Shizi Street Suzhou Jiangsu Province 215006, China
- Institute of Stroke Research, Soochow University, China
| | - Haitao Shen
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, 188 Shizi Street Suzhou Jiangsu Province 215006, China
- Institute of Stroke Research, Soochow University, China
| | - Xiang Li
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, 188 Shizi Street Suzhou Jiangsu Province 215006, China
- Institute of Stroke Research, Soochow University, China
| | - Haiying Li
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, 188 Shizi Street Suzhou Jiangsu Province 215006, China
- Institute of Stroke Research, Soochow University, China
| | - Jiang Wu
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, 188 Shizi Street Suzhou Jiangsu Province 215006, China
- Institute of Stroke Research, Soochow University, China
| | - Gang Chen
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, 188 Shizi Street Suzhou Jiangsu Province 215006, China
- Institute of Stroke Research, Soochow University, China
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4
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Khoja S, Liu XB, Truong B, Nitzahn M, Lambert J, Eliav A, Nasser E, Randolph E, Burke KE, White R, Zhu X, Martini PG, Nissim I, Cederbaum SD, Lipshutz GS. Intermittent lipid nanoparticle mRNA administration prevents cortical dysmyelination associated with arginase deficiency. MOLECULAR THERAPY. NUCLEIC ACIDS 2022; 28:859-874. [PMID: 35694211 PMCID: PMC9156989 DOI: 10.1016/j.omtn.2022.04.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 04/22/2022] [Indexed: 11/28/2022]
Abstract
Arginase deficiency is associated with prominent neuromotor features, including spastic diplegia, clonus, and hyperreflexia; intellectual disability and progressive neurological decline are other signs. In a constitutive murine model, we recently described leukodystrophy as a significant component of the central nervous system features of arginase deficiency. In the present studies, we sought to examine if the administration of a lipid nanoparticle carrying human ARG1 mRNA to constitutive knockout mice could prevent abnormalities in myelination associated with arginase deficiency. Imaging of the cingulum, striatum, and cervical segments of the corticospinal tract revealed a drastic reduction of myelinated axons; signs of degenerating axons were also present with thin myelin layers. Lipid nanoparticle/ARG1 mRNA administration resulted in both light and electron microscopic evidence of a dramatic recovery of myelin density compared with age-matched controls; oligodendrocytes were seen to be extending processes to wrap many axons. Abnormally thin myelin layers, when myelination was present, were resolved with intermittent mRNA administration, indicative of not only a greater density of myelinated axons but also an increase in the thickness of the myelin sheath. In conclusion, lipid nanoparticle/ARG1 mRNA administration in arginase deficiency prevents the associated leukodystrophy and restores normal oligodendrocyte function.
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Affiliation(s)
- Suhail Khoja
- Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Xiao-Bo Liu
- Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Brian Truong
- Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Matthew Nitzahn
- Molecular Biology Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Jenna Lambert
- Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Adam Eliav
- Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Eram Nasser
- Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Emma Randolph
- Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | | | - Rebecca White
- Moderna Inc., 200 Technology Square, Cambridge, MA 02139, USA
| | - Xuling Zhu
- Moderna Inc., 200 Technology Square, Cambridge, MA 02139, USA
| | | | - Itzhak Nissim
- Division of Metabolism and Human Genetics, The Children Hospital of Philadelphia and The Department of Biochemistry and Biophysics, Perlman School of Medicine, Philadelphia, PA 19104, USA
| | - Stephen D. Cederbaum
- Department of Psychiatry, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Intellectual and Developmental Disabilities Research Center at UCLA, Los Angeles, CA 90095, USA
- Semel Institute for Neuroscience, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Gerald S. Lipshutz
- Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Molecular Biology Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Department of Psychiatry, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Intellectual and Developmental Disabilities Research Center at UCLA, Los Angeles, CA 90095, USA
- Semel Institute for Neuroscience, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
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5
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Demerath T, Donkels C, Reisert M, Heers M, Rau A, Schröter N, Schulze-Bonhage A, Reinacher P, Scheiwe C, Shah MJ, Beck J, Vlachos A, Haas CA, Urbach H. Gray-White Matter Blurring of the Temporal Pole Associated With Hippocampal Sclerosis: A Microstructural Study Involving 3 T MRI and Ultrastructural Histopathology. Cereb Cortex 2021; 32:1882-1893. [PMID: 34515307 DOI: 10.1093/cercor/bhab320] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Hippocampal sclerosis (HS) is often associated with gray-white matter blurring (GMB) of the anterior temporal lobe. In this study, twenty patients with unilateral temporal lobe epilepsy and HS were studied with 3 T MRI including T1 MP2RAGE and DTI/DMI sequences. Anterior temporal lobe white matter T1 relaxation times and diffusion measures were analyzed on the HS side, on the contralateral side, and in 10 normal controls. Resected brain tissue of three patients without GMB and four patients with GMB was evaluated ultrastructurally regarding axon density and diameter, the relation of the axon diameter to the total fiber diameter (G-ratio), and the thickness of the myelin sheath. Hippocampal sclerosis GMB of the anterior temporal lobe was related to prolonged T1 relaxation and axonal loss. A less pronounced reduction in axonal fraction was also found on imaging in GMB-negative temporal poles compared with normal controls. Contralateral values did not differ significantly between patients and normal controls. Reduced axonal density and axonal diameter were histopathologically confirmed in the temporopolar white matter with GMB compared to temporal poles without. These results confirm that GMB can be considered an imaging correlate for disturbed axonal maturation that can be quantified with advanced diffusion imaging.
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Affiliation(s)
- T Demerath
- Department of Neuroradiology, Medical Center-University of Freiburg, Faculty of Medicine, 79106 Freiburg, Germany
| | - C Donkels
- Department of Neurosurgery, Experimental Epilepsy Research, Medical Center-University of Freiburg, Faculty of Medicine, 79106 Freiburg, Germany
| | - M Reisert
- Department of Medical Physics, Medical Center-University of Freiburg, Faculty of Medicine, 79106 Freiburg, Germany.,Deparment of Stereotactic and Functional Neurosurgery, Medical Center-University of Freiburg, 79106 Freiburg, Germany
| | - M Heers
- Epilepsy Center, Medical Center-University of Freiburg, 79106 Freiburg, Germany
| | - A Rau
- Department of Neuroradiology, Medical Center-University of Freiburg, Faculty of Medicine, 79106 Freiburg, Germany
| | - N Schröter
- Department of Neurology, Medical Center-University of Freiburg, 79106 Freiburg, Germany
| | - A Schulze-Bonhage
- Epilepsy Center, Medical Center-University of Freiburg, 79106 Freiburg, Germany
| | - P Reinacher
- Deparment of Stereotactic and Functional Neurosurgery, Medical Center-University of Freiburg, 79106 Freiburg, Germany.,Fraunhofer Institute for Laser Fraunhofer Institute for Laser Technology (ILT), Aachen, Germany
| | - C Scheiwe
- Department of Neurosurgery, Medical Center-University of Freiburg, 79106 Freiburg, Germany
| | - M J Shah
- Department of Neurosurgery, Medical Center-University of Freiburg, 79106 Freiburg, Germany
| | - J Beck
- Department of Neurosurgery, Medical Center-University of Freiburg, 79106 Freiburg, Germany.,Center for Basics in NeuroModulation, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - A Vlachos
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany.,Center for Basics in NeuroModulation, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - C A Haas
- Department of Neurosurgery, Experimental Epilepsy Research, Medical Center-University of Freiburg, Faculty of Medicine, 79106 Freiburg, Germany.,Center for Basics in NeuroModulation, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - H Urbach
- Department of Neuroradiology, Medical Center-University of Freiburg, Faculty of Medicine, 79106 Freiburg, Germany
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6
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Paasila PJ, Fok SYY, Flores‐Rodriguez N, Sajjan S, Svahn AJ, Dennis CV, Holsinger RMD, Kril JJ, Becker TS, Banati RB, Sutherland GT, Graeber MB. Ground state depletion microscopy as a tool for studying microglia-synapse interactions. J Neurosci Res 2021; 99:1515-1532. [PMID: 33682204 PMCID: PMC8251743 DOI: 10.1002/jnr.24819] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 02/02/2021] [Accepted: 02/06/2021] [Indexed: 01/09/2023]
Abstract
Ground state depletion followed by individual molecule return microscopy (GSDIM) has been used in the past to study the nanoscale distribution of protein co-localization in living cells. We now demonstrate the successful application of GSDIM to archival human brain tissue sections including from Alzheimer's disease cases as well as experimental tissue samples from mouse and zebrafish larvae. Presynaptic terminals and microglia and their cell processes were visualized at a resolution beyond diffraction-limited light microscopy, allowing clearer insights into their interactions in situ. The procedure described here offers time and cost savings compared to electron microscopy and opens the spectrum of molecular imaging using antibodies and super-resolution microscopy to the analysis of routine formalin-fixed paraffin sections of archival human brain. The investigation of microglia-synapse interactions in dementia will be of special interest in this context.
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Affiliation(s)
- Patrick Jarmo Paasila
- Faculty of Medicine and HealthCharles Perkins Centre and School of Medical SciencesThe University of SydneyCamperdownNSWAustralia
| | - Sandra Y. Y. Fok
- Biomedical Imaging FacilityMark Wainwright Analytical CentreUniversity of New South Wales SydneyKensingtonNSWAustralia
| | - Neftali Flores‐Rodriguez
- Charles Perkins CentreSydney Microscopy and MicroanalysisThe University of SydneyCamperdownNSWAustralia
| | - Sujata Sajjan
- Faculty of Medicine and HealthBrain and Mind CentreThe University of SydneyCamperdownNSWAustralia
| | - Adam J. Svahn
- Faculty of Medicine and HealthBrain and Mind CentreThe University of SydneyCamperdownNSWAustralia
| | - Claude V. Dennis
- Faculty of Medicine and HealthCharles Perkins Centre and School of Medical SciencesThe University of SydneyCamperdownNSWAustralia
| | - R. M. Damian Holsinger
- Faculty of Medicine and HealthBrain and Mind CentreThe University of SydneyCamperdownNSWAustralia
| | - Jillian J. Kril
- Faculty of Medicine and HealthCharles Perkins Centre and School of Medical SciencesThe University of SydneyCamperdownNSWAustralia
| | - Thomas S. Becker
- Faculty of Medicine and HealthBrain and Mind CentreThe University of SydneyCamperdownNSWAustralia
| | - Richard B. Banati
- Faculty of Medicine and HealthBrain and Mind CentreThe University of SydneyCamperdownNSWAustralia
- Life SciencesAustralian Nuclear Science and Technology OrganisationKirraweeNSWAustralia
| | - Greg T. Sutherland
- Faculty of Medicine and HealthCharles Perkins Centre and School of Medical SciencesThe University of SydneyCamperdownNSWAustralia
| | - Manuel B. Graeber
- Faculty of Medicine and HealthBrain and Mind CentreThe University of SydneyCamperdownNSWAustralia
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7
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Xu X, Cowan M, Beraldo F, Schranz A, McCunn P, Geremia N, Brown Z, Patel M, Nygard KL, Khazaee R, Lu L, Liu X, Strong MJ, Dekaban GA, Menon R, Bartha R, Daley M, Mao H, Prado V, Prado MAM, Saksida L, Bussey T, Brown A. Repetitive mild traumatic brain injury in mice triggers a slowly developing cascade of long-term and persistent behavioral deficits and pathological changes. Acta Neuropathol Commun 2021; 9:60. [PMID: 33823944 PMCID: PMC8025516 DOI: 10.1186/s40478-021-01161-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 03/17/2021] [Indexed: 12/15/2022] Open
Abstract
We have previously reported long-term changes in the brains of non-concussed varsity rugby players using magnetic resonance spectroscopy (MRS), diffusion tensor imaging (DTI) and functional magnetic imaging (fMRI). Others have reported cognitive deficits in contact sport athletes that have not met the diagnostic criteria for concussion. These results suggest that repetitive mild traumatic brain injuries (rmTBIs) that are not severe enough to meet the diagnostic threshold for concussion, produce long-term consequences. We sought to characterize the neuroimaging, cognitive, pathological and metabolomic changes in a mouse model of rmTBI. Using a closed-skull model of mTBI that when scaled to human leads to rotational and linear accelerations far below what has been reported for sports concussion athletes, we found that 5 daily mTBIs triggered two temporally distinct types of pathological changes. First, during the first days and weeks after injury, the rmTBI produced diffuse axonal injury, a transient inflammatory response and changes in diffusion tensor imaging (DTI) that resolved with time. Second, the rmTBI led to pathological changes that were evident months after the injury including: changes in magnetic resonance spectroscopy (MRS), altered levels of synaptic proteins, behavioural deficits in attention and spatial memory, accumulations of pathologically phosphorylated tau, altered blood metabolomic profiles and white matter ultrastructural abnormalities. These results indicate that exceedingly mild rmTBI, in mice, triggers processes with pathological consequences observable months after the initial injury.
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8
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Petrone P, Giordano G, Vezzoli E, Pensa A, Castaldo G, Graziano V, Sirano F, Capasso E, Quaremba G, Vona A, Miano MG, Savino S, Niola M. Preservation of neurons in an AD 79 vitrified human brain. PLoS One 2020; 15:e0240017. [PMID: 33022024 PMCID: PMC7537897 DOI: 10.1371/journal.pone.0240017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 09/17/2020] [Indexed: 12/03/2022] Open
Abstract
Detecting the ultrastructure of brain tissue in human archaeological remains is a rare event that can offer unique insights into the structure of the ancient central nervous system (CNS). Yet ancient brains reported in the literature show only poor preservation of neuronal structures. Using scanning electron microscopy (SEM) and advanced image processing tools, we describe the direct visualization of neuronal tissue in vitrified brain and spinal cord remains which we discovered in a male victim of the AD 79 eruption in Herculaneum. We show exceptionally well preserved ancient neurons from different regions of the human CNS at unprecedented resolution. This tissue typically consists of organic matter, as detected using energy-dispersive X-ray spectroscopy. By means of a self-developed neural image processing network, we also show specific details of the neuronal nanomorphology, like the typical myelin periodicity evidenced in the brain axons. The perfect state of preservation of these structures is due to the unique process of vitrification which occurred at Herculaneum. The discovery of proteins whose genes are expressed in the different region of the human adult brain further agree with the neuronal origin of the unusual archaeological find. The conversion of human tissue into glass is the result of sudden exposure to scorching volcanic ash and the concomitant rapid drop in temperature. The eruptive-induced process of natural vitrification, locking the cellular structure of the CNS, allowed us to study possibly the best known example in archaeology of extraordinarily well-preserved human neuronal tissue from the brain and spinal cord.
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Affiliation(s)
- Pierpaolo Petrone
- Dipartimento di Scienze Biomediche Avanzate, Università di Napoli Federico II, Naples, Italy
| | - Guido Giordano
- Dipartimento di Scienze, Università degli Studi Roma Tre, Rome, Italy
| | - Elena Vezzoli
- Dipartimento di Scienze Biomediche per la Salute, Università di Milano, Milan, Italy
| | - Alessandra Pensa
- Dipartimento di Scienze, Università degli Studi Roma Tre, Rome, Italy
| | | | - Vincenzo Graziano
- Dipartimento di Scienze Biomediche Avanzate, Università di Napoli Federico II, Naples, Italy
| | | | - Emanuele Capasso
- Dipartimento di Scienze Biomediche Avanzate, Università di Napoli Federico II, Naples, Italy
| | - Giuseppe Quaremba
- Dipartimento di Scienze Biomediche Avanzate, Università di Napoli Federico II, Naples, Italy
- Dipartimento di Ingegneria Industriale, Università di Napoli Federico II, Naples, Italy
| | - Alessandro Vona
- Dipartimento di Scienze, Università degli Studi Roma Tre, Rome, Italy
| | - Maria Giuseppina Miano
- Istituto di Genetica e Biofisica "Adriano Buzzati-Traverso”, Consiglio Nazionale delle Ricerche (CNR), Naples, Italy
| | - Sergio Savino
- Dipartimento di Ingegneria Industriale, Università di Napoli Federico II, Naples, Italy
| | - Massimo Niola
- Dipartimento di Scienze Biomediche Avanzate, Università di Napoli Federico II, Naples, Italy
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9
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Yakoubi R, Rollenhagen A, von Lehe M, Shao Y, Sätzler K, Lübke JHR. Quantitative Three-Dimensional Reconstructions of Excitatory Synaptic Boutons in Layer 5 of the Adult Human Temporal Lobe Neocortex: A Fine-Scale Electron Microscopic Analysis. Cereb Cortex 2020; 29:2797-2814. [PMID: 29931200 DOI: 10.1093/cercor/bhy146] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 05/22/2018] [Accepted: 05/29/2018] [Indexed: 11/14/2022] Open
Abstract
Studies of synapses are available for different brain regions of several animal species including non-human primates, but comparatively little is known about their quantitative morphology in humans. Here, synaptic boutons in Layer 5 (L5) of the human temporal lobe (TL) neocortex were investigated in biopsy tissue, using fine-scale electron microscopy, and quantitative three-dimensional reconstructions. The size and organization of the presynaptic active zones (PreAZs), postsynaptic densities (PSDs), and that of the 3 distinct pools of synaptic vesicles (SVs) were particularly analyzed. L5 synaptic boutons were medium-sized (~6 μm2) with a single but relatively large PreAZ (~0.3 μm2). They contained a total of ~1500 SVs/bouton, ~20 constituting the putative readily releasable pool (RRP), ~180 the recycling pool (RP), and the remainder, the resting pool. The PreAZs, PSDs, and vesicle pools are ~3-fold larger than those of CNS synapses in other species. Astrocytic processes reached the synaptic cleft and may regulate the glutamate concentration. Profound differences exist between synapses in human TL neocortex and those described in various species, particularly in the size and geometry of PreAZs and PSDs, the large RRP/RP, and the astrocytic ensheathment suggesting high synaptic efficacy, strength, and modulation of synaptic transmission at human synapses.
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Affiliation(s)
- Rachida Yakoubi
- Institute of Neuroscience and Medicine INM-10, Research Centre Jülich GmbH, Leo-Brandt Str., Jülich, Germany
| | - Astrid Rollenhagen
- Institute of Neuroscience and Medicine INM-10, Research Centre Jülich GmbH, Leo-Brandt Str., Jülich, Germany
| | - Marec von Lehe
- University Hospital/Knappschaftskrankenhaus Bochum, In der Schornau 23-25, Bochum, Germany.,Department of Neurosurgery, Ruppiner Kliniken, Medizinische Hochschule Brandenburg, Fehrbelliner Str. 38, Neuruppin, Germany
| | - Yachao Shao
- Simulation Lab Neuroscience, Research Centre Jülich GmbH, Leo-Brandt Str., Jülich, Germany.,College of Computer, National University of Defense Technology, Changsha, China
| | - Kurt Sätzler
- School of Biomedical Sciences, University of Ulster, Cromore Rd., BT52 1SA, Londonderry, UK
| | - Joachim H R Lübke
- Institute of Neuroscience and Medicine INM-10, Research Centre Jülich GmbH, Leo-Brandt Str., Jülich, Germany.,Department of Psychiatry, Psychotherapy and Psychosomatics, Medical Faculty/RWTH University Hospital Aachen, Pauwelsstr. 30, Aachen, Germany.,JARA Translational Brain Medicine, Germany
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10
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Synaptic Organization of the Human Temporal Lobe Neocortex as Revealed by High-Resolution Transmission, Focused Ion Beam Scanning, and Electron Microscopic Tomography. Int J Mol Sci 2020; 21:ijms21155558. [PMID: 32756507 PMCID: PMC7432700 DOI: 10.3390/ijms21155558] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 07/27/2020] [Accepted: 07/29/2020] [Indexed: 01/02/2023] Open
Abstract
Modern electron microscopy (EM) such as fine-scale transmission EM, focused ion beam scanning EM, and EM tomography have enormously improved our knowledge about the synaptic organization of the normal, developmental, and pathologically altered brain. In contrast to various animal species, comparably little is known about these structures in the human brain. Non-epileptic neocortical access tissue from epilepsy surgery was used to generate quantitative 3D models of synapses. Beside the overall geometry, the number, size, and shape of active zones and of the three functionally defined pools of synaptic vesicles representing morphological correlates for synaptic transmission and plasticity were quantified. EM tomography further allowed new insights in the morphological organization and size of the functionally defined readily releasable pool. Beside similarities, human synaptic boutons, although comparably small (approximately 5 µm), differed substantially in several structural parameters, such as the shape and size of active zones, which were on average 2 to 3-fold larger than in experimental animals. The total pool of synaptic vesicles exceeded that in experimental animals by approximately 2 to 3-fold, in particular the readily releasable and recycling pool by approximately 2 to 5-fold, although these pools seemed to be layer-specifically organized. Taken together, synaptic boutons in the human temporal lobe neocortex represent unique entities perfectly adapted to the “job” they have to fulfill in the circuitry in which they are embedded. Furthermore, the quantitative 3D models of synaptic boutons are useful to explain and even predict the functional properties of synaptic connections in the human neocortex.
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11
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Donkels C, Peters M, Fariña Núñez MT, Nakagawa JM, Kirsch M, Vlachos A, Scheiwe C, Schulze-Bonhage A, Prinz M, Beck J, Haas CA. Oligodendrocyte lineage and myelination are compromised in the gray matter of focal cortical dysplasia type IIa. Epilepsia 2019; 61:171-184. [PMID: 31872870 DOI: 10.1111/epi.16415] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 11/28/2019] [Accepted: 11/29/2019] [Indexed: 01/26/2023]
Abstract
OBJECTIVES Focal cortical dysplasias (FCDs) are local malformations of the human neocortex and a leading cause of medically intractable epilepsy. FCDs are characterized by local architectural disturbances of the neocortex and often by a blurred gray-white matter boundary indicating abnormal white matter myelination. We have recently shown that myelination is also compromised in the gray matter of dysplastic areas, since transcripts encoding factors for oligodendrocyte differentiation and myelination are downregulated and myelin fibers appear fractured and disorganized. METHODS Here, we characterized the gray matter-associated myelination pathology in detail by in situ hybridization, immunohistochemistry, and electron microscopy with markers for myelin, mature oligodendrocytes, and oligodendrocyte precursor cells in tissue sections of FCD IIa and control cortices. In addition, we isolated oligodendrocyte precursor cells from resected dysplastic tissue and performed proliferation assays. RESULTS We show that the proportion of myelinated gray matter is similar in the dysplastic cortex to that in controls and myelinated fibers extend up to layer III. On the ultrastructural level, however, we found that the myelin sheaths of layer V axons are thinner in dysplastic specimens than in controls. In addition, the density of oligodendrocyte precursor cells and of mature oligodendrocytes was reduced. Finally, we show for the first time that oligodendrocyte precursor cells isolated from resected dysplastic cortex have a reduced proliferation capacity in comparison to controls. SIGNIFICANCE These results indicate that proliferation and differentiation of oligodendrocyte precursor cells and the formation of myelin sheaths are compromised in FCD and might contribute to the epileptogenicity of this cortical malformation.
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Affiliation(s)
- Catharina Donkels
- Experimental Epilepsy Research, Department of Neurosurgery, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Myriam Peters
- Experimental Epilepsy Research, Department of Neurosurgery, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Mateo T Fariña Núñez
- Department of Neurosurgery, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Julia M Nakagawa
- Department of Neurosurgery, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Matthias Kirsch
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Andreas Vlachos
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Christian Scheiwe
- Department of Neurosurgery, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Andreas Schulze-Bonhage
- Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Epilepsy Center Freiburg, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,BrainLinks-BrainTools, Cluster of Excellence, University of Freiburg, Freiburg, Germany
| | - Marco Prinz
- Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Institute of Neuropathology, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Signalling Research Centers BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Jürgen Beck
- Department of Neurosurgery, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Carola A Haas
- Experimental Epilepsy Research, Department of Neurosurgery, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, Freiburg, Germany.,BrainLinks-BrainTools, Cluster of Excellence, University of Freiburg, Freiburg, Germany
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12
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Yakoubi R, Rollenhagen A, von Lehe M, Miller D, Walkenfort B, Hasenberg M, Sätzler K, Lübke JH. Ultrastructural heterogeneity of layer 4 excitatory synaptic boutons in the adult human temporal lobe neocortex. eLife 2019; 8:48373. [PMID: 31746736 PMCID: PMC6919978 DOI: 10.7554/elife.48373] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 11/19/2019] [Indexed: 01/09/2023] Open
Abstract
Synapses are fundamental building blocks controlling and modulating the ‘behavior’ of brain networks. How their structural composition, most notably their quantitative morphology underlie their computational properties remains rather unclear, particularly in humans. Here, excitatory synaptic boutons (SBs) in layer 4 (L4) of the temporal lobe neocortex (TLN) were quantitatively investigated. Biopsies from epilepsy surgery were used for fine-scale and tomographic electron microscopy (EM) to generate 3D-reconstructions of SBs. Particularly, the size of active zones (AZs) and that of the three functionally defined pools of synaptic vesicles (SVs) were quantified. SBs were comparatively small (~2.50 μm2), with a single AZ (~0.13 µm2); preferentially established on spines. SBs had a total pool of ~1800 SVs with strikingly large readily releasable (~20), recycling (~80) and resting pools (~850). Thus, human L4 SBs may act as ‘amplifiers’ of signals from the sensory periphery, integrate, synchronize and modulate intra- and extracortical synaptic activity.
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Affiliation(s)
- Rachida Yakoubi
- Institute of Neuroscience and Medicine INM-10, Research Centre Jülich GmbH, Jülich, Germany
| | - Astrid Rollenhagen
- Institute of Neuroscience and Medicine INM-10, Research Centre Jülich GmbH, Jülich, Germany
| | - Marec von Lehe
- Department of Neurosurgery, Knappschaftskrankenhaus Bochum, Bochum, Germany.,Department of Neurosurgery, Brandenburg Medical School, Ruppiner Clinics, Neuruppin, Germany
| | - Dorothea Miller
- Department of Neurosurgery, Knappschaftskrankenhaus Bochum, Bochum, Germany
| | - Bernd Walkenfort
- Medical Research Centre, IMCES Electron Microscopy Unit (EMU), University Hospital Essen, Essen, Germany
| | - Mike Hasenberg
- Medical Research Centre, IMCES Electron Microscopy Unit (EMU), University Hospital Essen, Essen, Germany
| | - Kurt Sätzler
- School of Biomedical Sciences, University of Ulster, Londonderry, United Kingdom
| | - Joachim Hr Lübke
- Institute of Neuroscience and Medicine INM-10, Research Centre Jülich GmbH, Jülich, Germany.,Department of Psychiatry, Psychotherapy and Psychosomatics, Faculty of Medicine, RWTH University Hospital Aachen, Aachen, Germany.,JARA Translational Brain Medicine, Jülich/Aachen, Germany
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13
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Liu XB, Haney JR, Cantero G, Lambert JR, Otero-Garcia M, Truong B, Gropman A, Cobos I, Cederbaum SD, Lipshutz GS. Hepatic arginase deficiency fosters dysmyelination during postnatal CNS development. JCI Insight 2019; 4:130260. [PMID: 31484827 DOI: 10.1172/jci.insight.130260] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 08/01/2019] [Indexed: 12/26/2022] Open
Abstract
Deficiency of arginase is associated with hyperargininemia, and prominent features include spastic diplegia/tetraplegia, clonus, and hyperreflexia; loss of ambulation, intellectual disability and progressive neurological decline are other signs. To gain greater insight into the unique neuromotor features, we performed gene expression profiling of the motor cortex of a murine model of the disorder. Coexpression network analysis suggested an abnormality with myelination, which was supported by limited existing human data. Utilizing electron microscopy, marked dysmyelination was detected in 2-week-old homozygous Arg1-KO mice. The corticospinal tract was found to be adversely affected, supporting dysmyelination as the cause of the unique neuromotor features and implicating oligodendrocyte impairment in a deficiency of hepatic Arg1. Following neonatal hepatic gene therapy to express Arg1, the subcortical white matter, pyramidal tract, and corticospinal tract all showed a remarkable recovery in terms of myelinated axon density and ultrastructural integrity with active wrapping of axons by nearby oligodendrocyte processes. These findings support the following conclusions: arginase deficiency is a leukodystrophy affecting the brain and spinal cord while sparing the peripheral nervous system, and neonatal AAV hepatic gene therapy can rescue the defects associated with myelinated axons, strongly implicating the functional recovery of oligodendrocytes after restoration of hepatic arginase activity.
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Affiliation(s)
| | - Jillian R Haney
- Department of Psychiatry.,Intellectual and Developmental Disabilities Research Center, and.,Semel Institute for Neuroscience, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Gloria Cantero
- Neuromuscular Disorders Unit, Department of Neurology, Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | | | | | - Brian Truong
- Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Andrea Gropman
- Neurogenetics and Neurodevelopmental Pediatrics and Genetics, Children's National Health System, Washington, DC, USA
| | - Inma Cobos
- Department of Pathology and Laboratory Medicine and
| | - Stephen D Cederbaum
- Department of Psychiatry.,Intellectual and Developmental Disabilities Research Center, and.,Semel Institute for Neuroscience, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Gerald S Lipshutz
- Department of Surgery.,Department of Psychiatry.,Intellectual and Developmental Disabilities Research Center, and.,Semel Institute for Neuroscience, David Geffen School of Medicine at UCLA, Los Angeles, California.,Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, California, USA.,Molecular Biology Institute, UCLA, Los Angeles, California, USA
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14
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Sele M, Wernitznig S, Lipovšek S, Radulović S, Haybaeck J, Birkl-Toeglhofer AM, Wodlej C, Kleinegger F, Sygulla S, Leoni M, Ropele S, Leitinger G. Optimization of ultrastructural preservation of human brain for transmission electron microscopy after long post-mortem intervals. Acta Neuropathol Commun 2019; 7:144. [PMID: 31481118 PMCID: PMC6724377 DOI: 10.1186/s40478-019-0794-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 08/24/2019] [Indexed: 12/16/2022] Open
Abstract
Electron microscopy (EM) provides the necessary resolution to visualize the finer structures of nervous tissue morphology, which is important to understand healthy and pathological conditions in the brain. However, for the interpretation of the micrographs the tissue preservation is crucial. The quality of the tissue structure is mostly influenced by the post mortem interval (PMI), the time of death until the preservation of the tissue. Therefore, the aim of this study was to optimize the preparation-procedure for the human frontal lobe to preserve the ultrastructure as well as possible despite the long PMIs. Combining chemical pre- and post-fixation with cryo-fixation and cryo-substitution ("hybrid freezing"), it was possible to improve the preservation of the neuronal profiles of human brain samples compared to the "standard" epoxy resin embedding method. In conclusion short PMIs are generally desirable but up to a PMI of 16 h the ultrastructure can be preserved on an acceptable level with a high contrast using the "hybrid freezing" protocol described here.
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15
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Imaging of post-mortem human brain tissue using electron and X-ray microscopy. Curr Opin Struct Biol 2019; 58:138-148. [PMID: 31349127 DOI: 10.1016/j.sbi.2019.06.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 05/26/2019] [Accepted: 06/10/2019] [Indexed: 12/12/2022]
Abstract
Electron microscopy imaging of post-mortem human brain (PMHB) comes with a unique set of challenges due to numerous parameters beyond the researcher's control. Nevertheless, the wealth of information provided by the ultrastructural analysis of PMHB is proving crucial in our understanding of neurodegenerative diseases. This review highlights the importance of such studies and covers challenges, limitations and recent developments in the application of current EM imaging, including cryo-ET and correlative hybrid techniques, on PMHB.
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16
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Glausier JR, Konanur A, Lewis DA. Factors Affecting Ultrastructural Quality in the Prefrontal Cortex of the Postmortem Human Brain. J Histochem Cytochem 2019; 67:185-202. [PMID: 30562121 PMCID: PMC6393839 DOI: 10.1369/0022155418819481] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2018] [Accepted: 11/19/2018] [Indexed: 12/13/2022] Open
Abstract
Electron microscopy (EM) studies of the postmortem human brain provide a level of resolution essential for understanding brain function in both normal and disease states. However, processes associated with death can impair the cellular and organelle ultrastructural preservation required for quantitative EM studies. Although postmortem interval (PMI), the time between death and preservation of tissue, is thought to be the most influential factor of ultrastructural quality, numerous other factors may also influence tissue preservation. The goal of the present study was to assess the effects of pre- and postmortem factors on multiple components of ultrastructure in the postmortem human prefrontal cortex. Tissue samples from 30 subjects were processed using standard EM histochemistry. The primary dependent measure was number of identifiable neuronal profiles, and secondary measures included presence and/or integrity of synapses, mitochondria, and myelinated axonal fibers. Number of identifiable neuronal profiles was most strongly affected by the interaction of PMI and pH, such that short PMIs and neutral pH values predicted the best preservation. Secondary measures were largely unaffected by pre- and postmortem factors. Together, these data indicate that distinct components of the neuropil are differentially affected by PMI and pH in postmortem human brain.
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Affiliation(s)
| | - Anisha Konanur
- The Dietrich School of Arts & Sciences, University of Pittsburgh
| | - David A. Lewis
- Department of Psychiatry, University of Pittsburgh
- Department of Neuroscience, University of Pittsburgh
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17
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Abstract
Premortem, postmortem, and storage conditions are parameters that can influence the quality and interpretation of data from studies of postmortem tissue. While many neurochemicals in the brain are relatively stable for several hours after death if stored at 4°C, the postmortem delay nevertheless becomes an important variable when examining the disease state because neurochemical levels may change with extended postmortem delay. Moreover, in the postmortem brain, neurochemical levels may also play a key role in determining the diagnosis. This is particularly true for some neurodegenerative disorders where many of the clinical features of the disease are not exclusive to one illness. It is therefore imperative to employ brain tissue of the highest quality from both nondiseased (control) and diseased brain tissue to ascertain the specific molecular and genetic mechanisms particular to the disease pathogenesis. Consequently, it would be very useful if specific markers could be employed to demonstrate and determine the quality of postmortem brain tissue that is suitable for such studies. In this chapter, the following neurochemical markers are critically reviewed as potential candidates to assess the quality of postmortem brain tissue: tryptophan levels, glutathione levels (and glutathione metabolic enzymes), enzymatic activities (glutamate decarboxylase, phosphofructokinase-1), epigenetic enzymes (acetyltransferase, methyltransferase), and tissue pH. In conclusion, the neurochemical tryptophan appears to be the most suitable candidate for assessing the integrity and quality of postmortem brain tissue. However, to optimize the quality of the samples, neuropathologic diagnostic characterization must also be employed in the interpretation and understanding of the data generated. It would also be judicious to consider as many premortem and postmortem conditions as possible as they can also affect the genetic and molecular integrity of the brain tissue.
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18
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Gu L, Wu D, Tang X, Qi X, Li X, Bai F, Chen X, Ren Q, Zhang Z. Myelin changes at the early stage of 5XFAD mice. Brain Res Bull 2017; 137:285-293. [PMID: 29288735 DOI: 10.1016/j.brainresbull.2017.12.013] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 12/08/2017] [Accepted: 12/26/2017] [Indexed: 02/08/2023]
Abstract
Previous studies have demonstrated myelin deficits in Alzheimer's disease (AD). However, it is still unclear whether myelin deficits occur at early stage of AD. Our study aimed to investigate myelin deficits in 5XFAD mice dynamically in different cognition-associated brain regions at early stage of AD. Transmission electron microscopy (TEM) was applied to detect myelin changes in late-myelinating regions such as prelimbic area (PrL), retrosplenial granular cortex (Rsg), field CA1 of hippocampus (CA1) and entorhinal cortex (ERC) respectively at different stages (1, 2, 3 and 5 months of age) in 5XFAD mouse model. In addition, we assessed spatial learning and memory with Morris water maze (MWM) in 5XFAD mice. Myelin deficits in 5XFAD mice started from 1 month of age and this deterioration continued during ageing, whereas the same myelin abnormality could only be observed in 5-month-old wild-type mice. Additionally, the g-ratio (an index associated with myelin thickness) was increased in 1-month-old 5XFAD mice in the regions including PrL, CA1 and ERC, compared to wild-type mice. As animals aged, the increased g-ratio in 5XFAD appeared in more regions of the brain. Moreover, 5XFAD mice showed spatial memory deficits from 1 month of age and spatial learning deficits from 2 months of age. In conclusion, myelin deficits occurred at an early stage and progressed with ageing in 5XFAD mouse model. Notably, a sequential myelin change was detected in cognition-associated brain regions. Combined with cognitive examinations, this study suggests that myelin changes might contribute to cognitive dysfunction.
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Affiliation(s)
- Lihua Gu
- Department of Neurology, Affiliated ZhongDa Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu, China
| | - Di Wu
- Department of Neurology, Affiliated ZhongDa Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu, China
| | - Xiang Tang
- Department of Neurology, Affiliated ZhongDa Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu, China
| | - Xinyang Qi
- Department of Neurology, Affiliated ZhongDa Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu, China
| | - Xiaoli Li
- Department of Neurology, Affiliated ZhongDa Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu, China
| | - Feng Bai
- Department of Neurology, Affiliated ZhongDa Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu, China
| | - Xiaochun Chen
- Department of Neurology, Fujian Institute of Geriatrics, the Affiliated Union Hospital of Fujian Medical University, Fuzhou, Fujian, China
| | - Qingguo Ren
- Department of Neurology, Affiliated ZhongDa Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu, China.
| | - Zhijun Zhang
- Department of Neurology, Affiliated ZhongDa Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu, China.
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19
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Bulk M, Abdelmoula WM, Nabuurs RJA, van der Graaf LM, Mulders CWH, Mulder AA, Jost CR, Koster AJ, van Buchem MA, Natté R, Dijkstra J, van der Weerd L. Postmortem MRI and histology demonstrate differential iron accumulation and cortical myelin organization in early- and late-onset Alzheimer's disease. Neurobiol Aging 2017; 62:231-242. [PMID: 29195086 DOI: 10.1016/j.neurobiolaging.2017.10.017] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 10/18/2017] [Accepted: 10/18/2017] [Indexed: 11/15/2022]
Abstract
Previous MRI studies reported cortical iron accumulation in early-onset (EOAD) compared to late-onset (LOAD) Alzheimer disease patients. However, the pattern and origin of iron accumulation is poorly understood. This study investigated the histopathological correlates of MRI contrast in both EOAD and LOAD. T2*-weighted MRI was performed on postmortem frontal cortex of controls, EOAD, and LOAD. Images were ordinally scored using predefined criteria followed by histology. Nonlinear histology-MRI registration was used to calculate pixel-wise spatial correlations based on the signal intensity. EOAD and LOAD were distinguishable based on 7T MRI from controls and from each other. Histology-MRI correlation analysis of the pixel intensities showed that the MRI contrast is best explained by increased iron accumulation and changes in cortical myelin, whereas amyloid and tau showed less spatial correspondence with T2*-weighted MRI. Neuropathologically, subtypes of Alzheimer's disease showed different patterns of iron accumulation and cortical myelin changes independent of amyloid and tau that may be detected by high-field susceptibility-based MRI.
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Affiliation(s)
- Marjolein Bulk
- Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands; Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands; Percuros BV, Leiden, the Netherlands.
| | - Walid M Abdelmoula
- Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Rob J A Nabuurs
- Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Linda M van der Graaf
- Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands; Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands
| | - Coen W H Mulders
- Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Aat A Mulder
- Department of Molecular Cell Biology, Electron Microscopy Section, Leiden University Medical Center, Leiden, the Netherlands
| | - Carolina R Jost
- Department of Molecular Cell Biology, Electron Microscopy Section, Leiden University Medical Center, Leiden, the Netherlands
| | - Abraham J Koster
- Department of Molecular Cell Biology, Electron Microscopy Section, Leiden University Medical Center, Leiden, the Netherlands
| | - Mark A van Buchem
- Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Remco Natté
- Department of Pathology, Leiden University Medical Center, Leiden, the Netherlands
| | - Jouke Dijkstra
- Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Louise van der Weerd
- Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands; Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands
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20
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Rescue of the Functional Alterations of Motor Cortical Circuits in Arginase Deficiency by Neonatal Gene Therapy. J Neurosci 2017; 36:6680-90. [PMID: 27335400 DOI: 10.1523/jneurosci.0897-16.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 05/11/2016] [Indexed: 01/28/2023] Open
Abstract
UNLABELLED Arginase 1 deficiency is a urea cycle disorder associated with hyperargininemia, spastic diplegia, loss of ambulation, intellectual disability, and seizures. To gain insight on how loss of arginase expression affects the excitability and synaptic connectivity of the cortical neurons in the developing brain, we used anatomical, ultrastructural, and electrophysiological techniques to determine how single-copy and double-copy arginase deletion affects cortical circuits in mice. We find that the loss of arginase 1 expression results in decreased dendritic complexity, decreased excitatory and inhibitory synapse numbers, decreased intrinsic excitability, and altered synaptic transmission in layer 5 motor cortical neurons. Hepatic arginase 1 gene therapy using adeno-associated virus rescued nearly all these abnormalities when administered to neonatal homozygous knock-out animals. Therefore, gene therapeutic strategies can reverse physiological and anatomical markers of arginase 1 deficiency and therefore may be of therapeutic benefit for the neurological disabilities in this syndrome. SIGNIFICANCE STATEMENT These studies are one of the few investigations to try to understand the underlying neurological dysfunction that occurs in urea cycle disorders and the only to examine arginase deficiency. We have demonstrated by multiple modalities that, in murine layer 5 cortical neurons, a gradation of abnormalities exists based on the functional copy number of arginase: intrinsic excitability is altered, there is decreased density in asymmetrical and perisomatic synapses, and analysis of the dendritic complexity is lowest in the homozygous knock-out. With neonatal administration of adeno-associated virus expressing arginase, there is near-total recovery of the abnormalities in neurons and cortical circuits, supporting the concept that neonatal gene therapy may prevent the functional abnormalities that occur in arginase deficiency.
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Papp-Peka A, Tong M, Kril JJ, De La Monte SM, Sutherland GT. The Differential Effects of Alcohol and Nicotine-Specific Nitrosamine Ketone on White Matter Ultrastructure. Alcohol Alcohol 2017; 52:165-171. [PMID: 28182194 PMCID: PMC6075461 DOI: 10.1093/alcalc/agw067] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Revised: 08/15/2016] [Accepted: 08/29/2016] [Indexed: 01/04/2023] Open
Abstract
Aims The chronic consumption of alcohol is known to result in neurodegeneration and impairment of cognitive function. Pathological and neuroimaging studies have confirmed that brain atrophy in alcoholics is mainly due to widespread white matter (WM) loss with neuronal loss restricted to specific regions, such as the prefrontal cortex. Neuroimaging studies of cigarette smokers also suggest that chronic inhalation of tobacco smoke leads to brain atrophy, although the neurotoxic component is unknown. As a high proportion of chronic alcoholics also smoke cigarettes it has been hypothesized that at least some alcohol-related brain damage is due to tobacco smoke exposure. Methods 39 Long Evans rats were subjected to 8 weeks exposure to alcohol and/or 5 weeks co-exposure to nicotine-specific nitrosamine ketone (NNK), a proxy for tobacco smoke. Their frontal WM was then assayed with transmission electron microscopy. Results NNK and ethanol co-exposure had a synergistic effect in decreasing myelinated fibre density. Furthermore, NNK treatment led to a greater reduction in myelin sheath thickness than ethanol whereas only the ethanol-treated animals showed a decrease in unmyelinated fibre density. Conclusion These data suggest that NNK causes WM degeneration, an effect that is exacerbated by alcohol, but unlike alcohol, it has little impact on the neuronal components of the brain.
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Affiliation(s)
- A Papp-Peka
- Charles Perkins Centre, Discipline of Pathology, School of Medical Sciences, The University of Sydney, Johns Hopkins Drive, Camperdown NSW 2050, Australia
| | | | - J J Kril
- Charles Perkins Centre, Discipline of Pathology, School of Medical Sciences, The University of Sydney, Johns Hopkins Drive, Camperdown NSW 2050, Australia
| | | | - G T Sutherland
- Charles Perkins Centre, Discipline of Pathology, School of Medical Sciences, The University of Sydney, Johns Hopkins Drive, Camperdown NSW 2050, Australia
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Krause M, Brüne M, Theiss C. Preparation of human formalin-fixed brain slices for electron microscopic investigations. Ann Anat 2016; 206:27-33. [PMID: 27136748 DOI: 10.1016/j.aanat.2016.04.030] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 04/13/2016] [Accepted: 04/15/2016] [Indexed: 10/21/2022]
Abstract
Ultra-structural analysis of human post-mortem brain tissue is important for investigations into the pathomechanism of neuropsychiatric disorders, especially those lacking alternative models of studying human-specific morphological features. For example, Von Economo Neurons (VENs) mainly located in the anterior cingulate cortex and in the anterior part of the insula, which seem to play a role in a variety of neuropsychiatric conditions, including frontotemporal dementia, autism and schizophrenia, can hardly be studied in nonhuman animals. Accordingly, little is known about the ultra-structural alterations of these neurons, though important research using qualitative stereological methods has revealed that protein expression of the VENs assigns them a role in immune function. Formaldehyde, which is the most common fixative in human pathology, interferes with the immunoreactivity of the tissue, possibly leading to unreliable results. Therefore, a method for ultra-structural investigations independent of antigenic properties of the fixated tissue is needed. Here, we propose an approach using electron microscopy to examine cytoskeletal structures, synapses and mitochondria in these cells. We also show that our methodology is able to keep tissue consumption to a minimum, while still allowing for the specimens to be handled with ease by using agar embedded slices in contrast to blocks for the embedding procedure. Accordingly, a stepwise protocol utilising 60μm thick human post mortem brain sections for electron microscopic ultra-structural investigations is presented.
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Affiliation(s)
- Martin Krause
- Institute of Anatomy, Department of Cytology, Ruhr-University Bochum, Germany
| | - Martin Brüne
- LWL University Hospital Bochum, Division of Cognitive Neuropsychiatry and Psychiatric Preventive Medicine, Ruhr-University Bochum, Germany
| | - Carsten Theiss
- Institute of Anatomy, Department of Cytology, Ruhr-University Bochum, Germany.
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How Klingler's dissection permits exploration of brain structural connectivity? An electron microscopy study of human white matter. Brain Struct Funct 2015; 221:2477-86. [PMID: 25905864 DOI: 10.1007/s00429-015-1050-7] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 04/20/2015] [Indexed: 12/21/2022]
Abstract
The objective of this study is to explore histological and ultrastructural changes induced by Klingler's method. Five human brains were prepared. First, the effects of freezing-defrosting on white matter were explored with optical microscopy on corpus callosum samples of two brains; one prepared in accordance with the description of Klingler (1956) and the other without freezing-defrosting. Then, the combined effect of formalin fixation and freezing-defrosting was explored with transmission electron microscopy (EM) on samples of cingulum from one brain: samples from one hemisphere were fixed in paraformaldehyde-glutaraldehyde (para/gluta), other samples from the other hemisphere were fixed in formalin; once fixed, half of the samples were frozen-defrosted. Finally, the effect of dissection was explored from three formalin-fixed brains: one hemisphere of each brain was frozen-defrosted; samples of the corpus callosum were dissected before preparation for scanning EM. Optical microscopy showed enlarged extracellular space on frozen samples. Transmission EM showed no significant alteration of white matter ultrastructure after formalin or para/gluta fixation. Freezing-defrosting created extra-axonal lacunas, larger on formalin-fixed than on para/gluta-fixed samples. In all cases, myelin sheaths were preserved, allowing maintenance of axonal integrity. Scanning EM showed the destruction of most of the extra-axonal structures after freezing-defrosting and the preservation of most of the axons after dissection. Our results are the first to highlight the effects of Klingler's preparation and dissection on white matter ultrastructure. Preservation of myelinated axons is a strong argument to support the reliability of Klingler's dissection to explore the structure of human white matter.
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Li J, Zhang L, Chen Z, Xie M, Huang L, Xue J, Liu Y, Liu N, Guo F, Zheng Y, Kong J, Zhang L, Zhang L. Cocaine activates Rac1 to control structural and behavioral plasticity in caudate putamen. Neurobiol Dis 2015; 75:159-76. [PMID: 25595128 DOI: 10.1016/j.nbd.2014.12.031] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 11/19/2014] [Accepted: 12/18/2014] [Indexed: 12/24/2022] Open
Abstract
Repeated exposure to cocaine was previously found to cause sensitized behavioral responses and structural remodeling on medium spiny neurons of the nucleus accumbens (NAc) and caudate putamen (CPu). Rac1 has emerged as a key integrator of environmental cues that regulates dendritic cytoskeletons. In this study, we investigated the role of Rac1 in cocaine-induced dendritic and behavioral plasticity in the CPu. We found that Rac1 activation was reduced in the NAc but increased in the CPu following repeated cocaine treatment. Inhibition of Rac1 activity by a Rac1-specific inhibitor NSC23766, overexpression of a dominant negative mutant of Rac1 (T17N-Rac1) or local knockout of Rac1 attenuated the cocaine-induced increase in dendrites and spine density in the CPu, whereas overexpression of a constitutively active Rac1 exert the opposite effect. Moreover, NSC23766 reversed the increased number of asymmetric spine synapses in the CPu following chronic cocaine exposure. Downregulation of Rac1 activity likewise attenuates behavioral reward responses to cocaine exposure, with activation of Rac1 producing the opposite effect. Thus, Rac1 signaling is differentially regulated in the NAc and CPu after repeated cocaine treatment, and induction of Rac1 activation in the CPu is important for cocaine exposure-induced dendritic remodeling and behavioral plasticity.
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Affiliation(s)
- Juan Li
- Key Laboratory of Functional Proteomics of Guangdong Province, Department of Pathophysiology, Southern Medical University, Guangzhou 510515, China; Department of Histology and Embryology, Southern Medical University, Guangzhou 510515, China
| | - Lei Zhang
- Department of Histology and Embryology, Southern Medical University, Guangzhou 510515, China
| | - Zhenzhong Chen
- Key Laboratory of Functional Proteomics of Guangdong Province, Department of Pathophysiology, Southern Medical University, Guangzhou 510515, China
| | - Minjuan Xie
- Key Laboratory of Functional Proteomics of Guangdong Province, Department of Pathophysiology, Southern Medical University, Guangzhou 510515, China
| | - Lu Huang
- Key Laboratory of Functional Proteomics of Guangdong Province, Department of Pathophysiology, Southern Medical University, Guangzhou 510515, China
| | - Jinhua Xue
- Key Laboratory of Functional Proteomics of Guangdong Province, Department of Pathophysiology, Southern Medical University, Guangzhou 510515, China
| | - Yutong Liu
- Key Laboratory of Functional Proteomics of Guangdong Province, Department of Pathophysiology, Southern Medical University, Guangzhou 510515, China
| | - Nuyun Liu
- Elderly Health Services Research Center, Southern Medical University, Guangzhou 510515, China
| | - Fukun Guo
- Division of Experimental Hematology and Cancer Biology, Children's Hospital Research Foundation, Cincinnati, OH, USA
| | - Yi Zheng
- Division of Experimental Hematology and Cancer Biology, Children's Hospital Research Foundation, Cincinnati, OH, USA
| | - Jiming Kong
- Southern Medical University-University of Manitoba Geriatric Medicine Joint Laboratory, Guangzhou 510515, China
| | - Lin Zhang
- Department of Histology and Embryology, Southern Medical University, Guangzhou 510515, China.
| | - Lu Zhang
- Key Laboratory of Functional Proteomics of Guangdong Province, Department of Pathophysiology, Southern Medical University, Guangzhou 510515, China; Elderly Health Services Research Center, Southern Medical University, Guangzhou 510515, China; Southern Medical University-University of Manitoba Geriatric Medicine Joint Laboratory, Guangzhou 510515, China.
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Liewald D, Miller R, Logothetis N, Wagner HJ, Schüz A. Distribution of axon diameters in cortical white matter: an electron-microscopic study on three human brains and a macaque. BIOLOGICAL CYBERNETICS 2014; 108:541-57. [PMID: 25142940 PMCID: PMC4228120 DOI: 10.1007/s00422-014-0626-2] [Citation(s) in RCA: 182] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2014] [Accepted: 08/05/2014] [Indexed: 05/18/2023]
Abstract
The aim of this study was to obtain information on the axonal diameters of cortico-cortical fibres in the human brain, connecting distant regions of the same hemisphere via the white matter. Samples for electron microscopy were taken from the region of the superior longitudinal fascicle and from the transitional white matter between temporal and frontal lobe where the uncinate and inferior occipitofrontal fascicle merge. We measured the inner diameter of cross sections of myelinated axons. For comparison with data from the literature on the human corpus callosum, we also took samples from that region. For comparison with well-fixed material, we also included samples from corresponding regions of a monkey brain (Macaca mulatta). Fibre diameters in human brains ranged from 0.16 to 9 μm. Distributions of diameters were similar in the three systems of cortico-cortical fibres investigated, both in humans and the monkey, with most of the average values below 1 μm diameter and a small population of much thicker fibres. Within individual human brains, the averages were larger in the superior longitudinal fascicle than in the transitional zone between temporal and frontal lobe. An asymmetry between left and right could be found in one of the human brains, as well as in the monkey brain. A correlation was also found between the thickness of the myelin sheath and the inner axon diameter for axons whose calibre was greater than about 0.6 μm. The results are compared to white matter data in other mammals and are discussed with respect to conduction velocity, brain size, cognition, as well as diffusion weighted imaging studies.
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Affiliation(s)
- Daniel Liewald
- Max Planck Institute for Biological Cybernetics, Spemannstr. 38/41, 72076 Tübingen, Germany
| | - Robert Miller
- Department of Psychological Medicine, University of Otago, Wellington, New Zealand
| | - Nikos Logothetis
- Max Planck Institute for Biological Cybernetics, Spemannstr. 38/41, 72076 Tübingen, Germany
| | | | - Almut Schüz
- Max Planck Institute for Biological Cybernetics, Spemannstr. 38/41, 72076 Tübingen, Germany
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