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Clark JR, Camus AC, Comolli J, Divers SJ, Gendron KP. MRI of the live fish brain at 3 Tesla: Feasibility, technique and interspecies anatomic variations. Vet Radiol Ultrasound 2023; 64:75-85. [PMID: 35790052 DOI: 10.1111/vru.13128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 04/29/2022] [Indexed: 01/25/2023] Open
Abstract
Advances in aquatic animal medicine and continued growth of the fish hobbyist and aquaculture communities have led to a developing interest in antemortem diagnostic imaging of aquatic species. The aims of this prospective, pilot study were to determine whether advanced neuroimaging can be safely achieved in live fish using clinically available equipment, to optimize imaging parameters, and to develop a comparative MRI atlas of a few fish species of economic or research value. Two each of channel catfish (Ictalurus punctatus), koi (Cyprinus rubrofuscus), and grass carp (Ctenopharyngodon idella) of at least 30 cm in length were individually anesthetized for 3 Tesla (3T) magnetic resonance imaging (MRI) of the brain. All fish achieved an adequate anesthetic level for prolonged immobilization during imaging. Diagnostic quality images were obtained for all subjects; however, the spatial resolution was maximized with larger fish. Imaging protocols were optimized for standard neuroimaging sequences. Additionally, inversion times for fluid-attenuation inversion recovery (FLAIR) sequences were adapted to the naturally high protein content of fish pericerebral fluid. Following imaging, the fish successfully recovered from anesthesia, were humanely euthanized, and were immediately processed to assess brain histopathology. Necropsy confirmed the sex and health status of each fish. A limited comparative MRI atlas was created of the brains of these species for clinical reference. Findings from the current study supported the use of 3T MRI as an adjunct diagnostic test for fish with suspected neurologic disease and provided a limited anatomic atlas of the teleost brain for use as a reference.
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Affiliation(s)
- Jennifer R Clark
- Veterinary Emergency and Referral Center of Honolulu, Honolulu, Hawaii, USA
| | - Alvin C Camus
- College of Veterinary Medicine, Department of Pathology, University of Georgia, Athens, Georgia, USA
| | - Jessica Comolli
- College of Veterinary Medicine, Department of Small Animal Medicine and Surgery, University of Georgia, Athens, Georgia, USA
| | - Stephen J Divers
- College of Veterinary Medicine, Department of Small Animal Medicine and Surgery, University of Georgia, Athens, Georgia, USA
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Liu H, Prokosch V. Energy Metabolism in the Inner Retina in Health and Glaucoma. Int J Mol Sci 2021; 22:ijms22073689. [PMID: 33916246 PMCID: PMC8036449 DOI: 10.3390/ijms22073689] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 03/22/2021] [Accepted: 03/29/2021] [Indexed: 02/07/2023] Open
Abstract
Glaucoma, the leading cause of irreversible blindness, is a heterogeneous group of diseases characterized by progressive loss of retinal ganglion cells (RGCs) and their axons and leads to visual loss and blindness. Risk factors for the onset and progression of glaucoma include systemic and ocular factors such as older age, lower ocular perfusion pressure, and intraocular pressure (IOP). Early signs of RGC damage comprise impairment of axonal transport, downregulation of specific genes and metabolic changes. The brain is often cited to be the highest energy-demanding tissue of the human body. The retina is estimated to have equally high demands. RGCs are particularly active in metabolism and vulnerable to energy insufficiency. Understanding the energy metabolism of the inner retina, especially of the RGCs, is pivotal for understanding glaucoma’s pathophysiology. Here we review the key contributors to the high energy demands in the retina and the distinguishing features of energy metabolism of the inner retina. The major features of glaucoma include progressive cell death of retinal ganglions and optic nerve damage. Therefore, this review focuses on the energetic budget of the retinal ganglion cells, optic nerve and the relevant cells that surround them.
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Alves de Lima K, Rustenhoven J, Kipnis J. Meningeal Immunity and Its Function in Maintenance of the Central Nervous System in Health and Disease. Annu Rev Immunol 2020; 38:597-620. [DOI: 10.1146/annurev-immunol-102319-103410] [Citation(s) in RCA: 109] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Neuroimmunology, albeit a relatively established discipline, has recently sparked numerous exciting findings on microglia, the resident macrophages of the central nervous system (CNS). This review addresses meningeal immunity, a less-studied aspect of neuroimmune interactions. The meninges, a triple layer of membranes—the pia mater, arachnoid mater, and dura mater—surround the CNS, encompassing the cerebrospinal fluid produced by the choroid plexus epithelium. Unlike the adjacent brain parenchyma, the meninges contain a wide repertoire of immune cells. These constitute meningeal immunity, which is primarily concerned with immune surveillance of the CNS, and—according to recent evidence—also participates in postinjury CNS recovery, chronic neurodegenerative conditions, and even higher brain function. Meningeal immunity has recently come under the spotlight owing to the characterization of meningeal lymphatic vessels draining the CNS. Here, we review the current state of our understanding of meningeal immunity and its effects on healthy and diseased brains.
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Affiliation(s)
- Kalil Alves de Lima
- Center for Brain Immunology and Glia (BIG) and Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, Virginia 22908, USA;,
| | - Justin Rustenhoven
- Center for Brain Immunology and Glia (BIG) and Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, Virginia 22908, USA;,
| | - Jonathan Kipnis
- Center for Brain Immunology and Glia (BIG) and Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, Virginia 22908, USA;,
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van Lessen M, Shibata-Germanos S, van Impel A, Hawkins TA, Rihel J, Schulte-Merker S. Intracellular uptake of macromolecules by brain lymphatic endothelial cells during zebrafish embryonic development. eLife 2017; 6. [PMID: 28498105 PMCID: PMC5457137 DOI: 10.7554/elife.25932] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 05/11/2017] [Indexed: 01/01/2023] Open
Abstract
The lymphatic system controls fluid homeostasis and the clearance of macromolecules from interstitial compartments. In mammals brain lymphatics were only recently discovered, with significant implications for physiology and disease. We examined zebrafish for the presence of brain lymphatics and found loosely connected endothelial cells with lymphatic molecular signature covering parts of the brain without forming endothelial tubular structures. These brain lymphatic endothelial cells (BLECs) derive from venous endothelium, are distinct from macrophages, and are sensitive to loss of Vegfc. BLECs endocytose macromolecules in a selective manner, which can be blocked by injection of mannose receptor ligands. This first report on brain lymphatic endothelial cells in a vertebrate embryo identifies cells with unique features, including the uptake of macromolecules at a single cell level. Future studies will address whether this represents an uptake mechanism that is conserved in mammals and how these cells affect functions of the embryonic and adult brain. DOI:http://dx.doi.org/10.7554/eLife.25932.001
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Affiliation(s)
- Max van Lessen
- Institute of Cardiovascular Organogenesis and Regeneration, WWU Münster, Münster, Germany.,Faculty of Medicine, WWU Münster, Münster, Germany.,Cells-in-Motion Cluster of Excellence, WWU Münster, Münster, Germany
| | | | - Andreas van Impel
- Institute of Cardiovascular Organogenesis and Regeneration, WWU Münster, Münster, Germany.,Faculty of Medicine, WWU Münster, Münster, Germany.,Cells-in-Motion Cluster of Excellence, WWU Münster, Münster, Germany
| | - Thomas A Hawkins
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Jason Rihel
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Stefan Schulte-Merker
- Institute of Cardiovascular Organogenesis and Regeneration, WWU Münster, Münster, Germany.,Faculty of Medicine, WWU Münster, Münster, Germany.,Cells-in-Motion Cluster of Excellence, WWU Münster, Münster, Germany
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Wilkie MP, Stecyk JAW, Couturier CS, Sidhu S, Sandvik GK, Nilsson GE. Reversible brain swelling in crucian carp (Carassius carassius) and goldfish (Carassius auratus) in response to high external ammonia and anoxia. Comp Biochem Physiol A Mol Integr Physiol 2015; 184:65-75. [PMID: 25582543 DOI: 10.1016/j.cbpa.2014.12.038] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 12/30/2014] [Accepted: 12/31/2014] [Indexed: 01/15/2023]
Abstract
Increased internal ammonia (hyperammonemia) and ischemic/anoxic insults are known to result in a cascade of deleterious events that can culminate in potentially fatal brain swelling in mammals. It is less clear, however, if the brains of fishes respond to ammonia in a similar manner. The present study demonstrated that the crucian carp (Carassius carassius) was not only able to endure high environmental ammonia exposure (HEA; 2 to 22 mmol L(-1)) but that they experienced 30% increases in brain water content at the highest ammonia concentrations. This swelling was accompanied by 4-fold increases in plasma total ammonia (TAmm) concentration, but both plasma TAmm and brain water content were restored to pre-exposure levels following depuration in ammonia-free water. The closely related, ammonia-tolerant goldfish (Carassius auratus) responded similarly to HEA (up to 3.6 mmol L(-1)), which was accompanied by 4-fold increases in brain glutamine. Subsequent administration of the glutamine synthetase inhibitor, methionine sulfoximine (MSO), reduced brain glutamine accumulation by 80% during HEA. However, MSO failed to prevent ammonia-induced increases in brain water content suggesting that glutamine may not be directly involved in initiating ammonia-induced brain swelling in fishes. Although the mechanisms of brain swelling are likely different, exposure to anoxia for 96 h caused similar, but lesser (10%) increases in brain water content in crucian carp. We conclude that brain swelling in some fishes may be a common response to increased internal ammonia or lower oxygen but further research is needed to deduce the underlying mechanisms behind such responses.
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Affiliation(s)
- Michael P Wilkie
- Department of Biology and Institute for Water Science, Wilfrid Laurier University, Waterloo, Ontario N2L 3C5, Canada; Department of Biosciences, University of Oslo, Oslo, Norway.
| | - Jonathan A W Stecyk
- Department of Biosciences, University of Oslo, Oslo, Norway; Department of Biological Sciences, University of Alaska Anchorage, Anchorage, USA
| | | | - Sanya Sidhu
- Department of Biology and Institute for Water Science, Wilfrid Laurier University, Waterloo, Ontario N2L 3C5, Canada
| | - Guro K Sandvik
- Department of Biosciences, University of Oslo, Oslo, Norway
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Paralikar KJ, Clement RS. Collagenase-Aided Intracortical Microelectrode Array Insertion: Effects on Insertion Force and Recording Performance. IEEE Trans Biomed Eng 2008; 55:2258-67. [DOI: 10.1109/tbme.2008.923150] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Hoffmann W, Schwarz H. Ependymins: meningeal-derived extracellular matrix proteins at the blood-brain barrier. INTERNATIONAL REVIEW OF CYTOLOGY 1996; 165:121-58. [PMID: 8900958 DOI: 10.1016/s0074-7696(08)62221-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Ependymins represent regeneration-responsive piscine glycoproteins and in many teleost fish they appear as the predominant cerebrospinal fluid constituents. Thus far, no homologous sequences have been characterized unambiguously in mammals. Sialic acid residues of the N-linked carbohydrate moiety of ependymins are responsible for their calcium-binding capacity. Ependymins from some species bear the L2/HNK-1 epitope typical of many cell adhesion molecules. After their synthesis in fibroblast-like cells of the inner endomeningeal layer, soluble ependymins are widely distributed via the cerebrospinal fluid system. Furthermore, ependymins presumably cross the intermediate endomeningeal barrier layer by way of a transcellular transport phenomenon (transcytosis). A bound form of ependymins is associated with collagen fibrils of the extracellular matrix typically found around cerebral blood vessels. Here, they might modulate the endothelial barrier function. Generally, ependymins are thought to represent a new class of possibly antiadhesive extracellular matrix proteins playing a role in specific cell contact phenomena (e.g., during regeneration).
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Affiliation(s)
- W Hoffmann
- Institut für Molekularbiologie und Medizinische Chemie, Otto-von-Guericke-Universität, Magdeburg, Germany
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