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Benagiano V, Rizzi A, Sannace C, Alessio G, Ribatti D, Dammacco R. Aqueous humor as eye lymph: A crossroad between venous and lymphatic system. Exp Eye Res 2024; 243:109904. [PMID: 38642600 DOI: 10.1016/j.exer.2024.109904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 03/18/2024] [Accepted: 04/17/2024] [Indexed: 04/22/2024]
Abstract
Aqueous humor (AQH) is a transparent fluid with characteristics similar to those of the interstitial fluid, which fills the eyeball posterior and anterior chambers and circulates in them from the sites of production to those of drainage. The AQH volume and pressure homeostasis is essential for the trophism of the ocular avascular tissues and their normal structure and function. Different AQH outflow pathways exist, including a main pathway, quite well defined anatomically and referred to as the conventional pathway, and some accessory pathways, more recently described and still not fully morphofunctionally understood, generically referred to as unconventional pathways. The conventional pathway is based on the existence of a series of conduits starting with the trabecular meshwork and Schlemm's Canal and continuing with a system of intrascleral and episcleral venules, which are tributaries to veins of the anterior segment of the eyeball. The unconventional pathways are mainly represented by the uveoscleral pathway, in which AQH flows through clefts, interstitial conduits located in the ciliary body and sclera, and then merges into the aforementioned intrascleral and episcleral venules. A further unconventional pathway, the lymphatic pathway, has been supported by the demonstration of lymphatic microvessels in the limbal sclera and, possibly, in the uvea (ciliary body, choroid) as well as by the ocular glymphatic channels, present in the neural retina and optic nerve. It follows that AQH may be drained from the eyeball through blood vessels (TM-SC pathway, US pathway) or lymphatic vessels (lymphatic pathway), and the different pathways may integrate or compensate for each other, optimizing the AQH drainage. The present review aims to define the state-of-the-art concerning the structural organization and the functional anatomy of all the AQH outflow pathways. Particular attention is paid to examining the regulatory mechanisms active in each of them. The new data on the anatomy and physiology of AQH outflow pathways is the key to understanding the pathophysiology of AQH outflow disorders and could open the way for novel approaches to their treatment.
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Affiliation(s)
- Vincenzo Benagiano
- Department of Translational Biomedicine and Neuroscience, University of Bari 'Aldo Moro', Bari, Italy.
| | - Anna Rizzi
- Department of Translational Biomedicine and Neuroscience, University of Bari 'Aldo Moro', Bari, Italy
| | - Carmela Sannace
- Azienda Sanitaria Locale Bari, Ophthalmology Day Service Triggiano-Gioia del Colle, Bari, Italy
| | - Giovanni Alessio
- Department of Translational Biomedicine and Neuroscience, University of Bari 'Aldo Moro', Bari, Italy
| | - Domenico Ribatti
- Department of Translational Biomedicine and Neuroscience, University of Bari 'Aldo Moro', Bari, Italy
| | - Rosanna Dammacco
- Department of Translational Biomedicine and Neuroscience, University of Bari 'Aldo Moro', Bari, Italy
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2
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Delle C, Wang X, Nedergaard M. The Ocular Glymphatic System-Current Understanding and Future Perspectives. Int J Mol Sci 2024; 25:5734. [PMID: 38891923 PMCID: PMC11172116 DOI: 10.3390/ijms25115734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 05/18/2024] [Accepted: 05/20/2024] [Indexed: 06/21/2024] Open
Abstract
The ocular glymphatic system subserves the bidirectional polarized fluid transport in the optic nerve, whereby cerebrospinal fluid from the brain is directed along periarterial spaces towards the eye, and fluid from the retina is directed along perivenous spaces following upon its axonal transport across the glial lamina. Fluid homeostasis and waste removal are vital for retinal function, making the ocular glymphatic fluid pathway a potential route for targeted manipulation to combat blinding ocular diseases such as age-related macular degeneration, diabetic retinopathy, and glaucoma. Several lines of work investigating the bidirectional ocular glymphatic transport with varying methodologies have developed diverging mechanistic models, which has created some confusion about how ocular glymphatic transport should be defined. In this review, we provide a comprehensive summary of the current understanding of the ocular glymphatic system, aiming to address misconceptions and foster a cohesive understanding of the topic.
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Affiliation(s)
- Christine Delle
- Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark;
| | - Xiaowei Wang
- Center for Translational Neuromedicine, University of Rochester Medical Center, Elmwood Avenue 601, Rochester, NY 14642, USA;
- Department of Ophthalmology, University of California, 10 Koret Way, San Francisco, CA 94117, USA
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark;
- Center for Translational Neuromedicine, University of Rochester Medical Center, Elmwood Avenue 601, Rochester, NY 14642, USA;
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3
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Rees JH, Rempe T, Tuna IS, Perero MM, Sabat S, Massini T, Yetto JM. Neuromyelitis Optica Spectrum Disorders and Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disease. Magn Reson Imaging Clin N Am 2024; 32:233-251. [PMID: 38555139 DOI: 10.1016/j.mric.2023.12.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/02/2024]
Abstract
For over two centuries, clinicians have been aware of various conditions affecting white matter which had come to be grouped under the umbrella term multiple sclerosis. Within the last 20 years, specific scientific advances have occurred leading to more accurate diagnosis and differentiation of several of these conditions including, neuromyelitis optica spectrum disorders and myelin oligodendrocyte glycoprotein antibody disease. This new understanding has been coupled with advances in disease-modifying therapies which must be accurately applied for maximum safety and efficacy.
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Affiliation(s)
- John H Rees
- Neuroradiology, Department of Radiology, University of Florida College of Medicine.
| | - Torge Rempe
- UF Multiple Sclerosis / Neuroimmunology Fellowship, Department of Neurology, University of Florida, College of Medicine
| | | | | | | | | | - Joseph M Yetto
- University of Florida at Gainesville, Gainesville, FL, USA
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4
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Cibelli A, Mola MG, Saracino E, Barile B, Abbrescia P, Mogni G, Spray DC, Scemes E, Rossi A, Spennato D, Svelto M, Frigeri A, Benfenati V, Nicchia GP. Aquaporin-4 and transient receptor potential vanilloid 4 balance in early postnatal neurodevelopment. Glia 2024; 72:938-959. [PMID: 38362923 DOI: 10.1002/glia.24512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 01/15/2024] [Accepted: 01/19/2024] [Indexed: 02/17/2024]
Abstract
In the adult brain, the water channel aquaporin-4 (AQP4) is expressed in astrocyte endfoot, in supramolecular assemblies, called "Orthogonal Arrays of Particles" (OAPs) together with the transient receptor potential vanilloid 4 (TRPV4), finely regulating the cell volume. The present study aimed at investigating the contribution of AQP4 and TRPV4 to CNS early postnatal development using WT and AQP4 KO brain and retina and neuronal stem cells (NSCs), as an in vitro model of astrocyte differentiation. Western blot analysis showed that, differently from AQP4 and the glial cell markers, TRPV4 was downregulated during CNS development and NSC differentiation. Blue native/SDS-PAGE revealed that AQP4 progressively organized into OAPs throughout the entire differentiation process. Fluorescence quenching assay indicated that the speed of cell volume changes was time-related to NSC differentiation and functional to their migratory ability. Calcium imaging showed that the amplitude of TRPV4 Ca2+ transient is lower, and the dynamics are changed during differentiation and suppressed in AQP4 KO NSCs. Overall, these findings suggest that early postnatal neurodevelopment is subjected to temporally modulated water and Ca2+ dynamics likely to be those sustaining the biochemical and physiological mechanisms responsible for astrocyte differentiation during brain and retinal development.
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Affiliation(s)
- Antonio Cibelli
- Department of Biosciences, Biotechnology and Environment, University of Bari Aldo Moro, Bari, Italy
| | - Maria Grazia Mola
- Department of Biosciences, Biotechnology and Environment, University of Bari Aldo Moro, Bari, Italy
| | - Emanuela Saracino
- Institute for Organic Synthesis and Photoreactivity (ISOF), National Research Council of Italy (CNR), Bologna, Italy
| | - Barbara Barile
- Department of Biosciences, Biotechnology and Environment, University of Bari Aldo Moro, Bari, Italy
| | - Pasqua Abbrescia
- Department of Translational Biomedicine and Neuroscience, University of Bari Aldo Moro-Medical School, Bari, Italy
| | - Guido Mogni
- Department of Biosciences, Biotechnology and Environment, University of Bari Aldo Moro, Bari, Italy
| | - David C Spray
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Eliana Scemes
- Department of Cell Biology and Anatomy, NY Medical College, Valhalla, New York, USA
| | - Andrea Rossi
- Genome Engineering and Model Development Lab (GEMD), IUF-Leibniz Research Institute for Environmental Medicine, Düsseldorf, Germany
| | - Diletta Spennato
- Institute for Organic Synthesis and Photoreactivity (ISOF), National Research Council of Italy (CNR), Bologna, Italy
| | - Maria Svelto
- Department of Biosciences, Biotechnology and Environment, University of Bari Aldo Moro, Bari, Italy
| | - Antonio Frigeri
- Department of Translational Biomedicine and Neuroscience, University of Bari Aldo Moro-Medical School, Bari, Italy
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Valentina Benfenati
- Institute for Organic Synthesis and Photoreactivity (ISOF), National Research Council of Italy (CNR), Bologna, Italy
| | - Grazia Paola Nicchia
- Department of Biosciences, Biotechnology and Environment, University of Bari Aldo Moro, Bari, Italy
- Institute for Organic Synthesis and Photoreactivity (ISOF), National Research Council of Italy (CNR), Bologna, Italy
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, USA
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5
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Tong XJ, Akdemir G, Wadhwa M, Verkman AS, Smith AJ. Large molecules from the cerebrospinal fluid enter the optic nerve but not the retina of mice. Fluids Barriers CNS 2024; 21:1. [PMID: 38178155 PMCID: PMC10768282 DOI: 10.1186/s12987-023-00506-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 12/21/2023] [Indexed: 01/06/2024] Open
Abstract
It has been proposed that cerebrospinal fluid (CSF) can enter and leave the retina and optic nerve along perivascular spaces surrounding the central retinal vessels as part of an aquaporin-4 (AQP4) dependent ocular 'glymphatic' system. Here, we injected fluorescent dextrans and antibodies into the CSF of mice at the cisterna magna and measured their distribution in the optic nerve and retina. We found that uptake of dextrans in the perivascular spaces and parenchyma of the optic nerve is highly sensitive to the cisternal injection rate, where high injection rates, in which dextran disperses fully in the sub-arachnoid space, led to uptake along the full length of the optic nerve. Accumulation of dextrans in the optic nerve did not differ significantly in wild-type and AQP4 knockout mice. Dextrans did not enter the retina, even when intracranial pressure was greatly increased over intraocular pressure. However, elevation of intraocular pressure reduced accumulation of fluorescent dextrans in the optic nerve head, and intravitreally injected dextrans left the retina via perivascular spaces surrounding the central retinal vessels. Human IgG distributed throughout the perivascular and parenchymal areas of the optic nerve to a similar extent as dextran following cisternal injection. However, uptake of a cisternally injected AQP4-IgG antibody, derived from a seropositive neuromyelitis optica spectrum disorder subject, was limited by AQP4 binding. We conclude that large molecules injected in the CSF can accumulate along the length of the optic nerve if they are fully dispersed in the optic nerve sub-arachnoid space but that they do not enter the retina.
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Affiliation(s)
- Xiao J Tong
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA, 94131, USA
| | - Gokhan Akdemir
- Departments of Medicine and Physiology, University of California San Francisco, San Francisco, CA, 94131, USA
| | - Meetu Wadhwa
- Departments of Medicine and Physiology, University of California San Francisco, San Francisco, CA, 94131, USA
| | - Alan S Verkman
- Departments of Medicine and Physiology, University of California San Francisco, San Francisco, CA, 94131, USA
| | - Alex J Smith
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA, 94131, USA.
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6
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Jazaeri SZ, Taghizadeh G, Babaei JF, Goudarzi S, Saadatmand P, Joghataei MT, Khanahmadi Z. Aquaporin 4 beyond a water channel; participation in motor, sensory, cognitive and psychological performances, a comprehensive review. Physiol Behav 2023; 271:114353. [PMID: 37714320 DOI: 10.1016/j.physbeh.2023.114353] [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: 06/05/2023] [Revised: 08/15/2023] [Accepted: 09/13/2023] [Indexed: 09/17/2023]
Abstract
Aquaporin 4 (AQP4) is a protein highly expressed in the central nervous system (CNS) and peripheral nervous system (PNS) as well as various other organs, whose different sites of action indicate its importance in various functions. AQP4 has a variety of essential roles beyond water homeostasis. In this article, we have for the first time summarized different roles of AQP4 in motor and sensory functions, besides cognitive and psychological performances, and most importantly, possible physiological mechanisms by which AQP4 can exert its effects. Furthermore, we demonstrated that AQP4 participates in pathology of different neurological disorders, various effects depending on the disease type. Since neurological diseases involve a spectrum of dysfunctions and due to the difficulty of obtaining a treatment that can simultaneously affect these deficits, it is therefore suggested that future studies consider the role of this protein in different functional impairments related to neurological disorders simultaneously or separately by targeting AQP4 expression and/or polarity modulation.
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Affiliation(s)
- Seyede Zohreh Jazaeri
- Department of Neuroscience, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran, Iran; Division of Neuroscience, Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Ghorban Taghizadeh
- Department of Occupational Therapy, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran.
| | - Javad Fahanik Babaei
- Electrophysiology Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Sepideh Goudarzi
- Experimental Medicine Research Center, Tehran University of medical Sciences, Tehran, Iran
| | - Pegah Saadatmand
- Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Mohammad Taghi Joghataei
- Department of Neuroscience, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran, Iran; Division of Neuroscience, Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran; Department of Anatomy, School of Medicine, Iran University of Medical Sciences, Tehran, Iran; Department of Innovation in Medical Education, Faculty of Medicine, Ottawa University, Ottawa, Canada.
| | - Zohreh Khanahmadi
- Department of Occupational Therapy, School of Rehabilitation Services, Isfahan University of Medical Sciences, Isfahan, Iran
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7
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Chan-Ling T, Hu P, Li Calzi S, Warner J, Uddin N, DuPont M, Neuringer M, Kievit P, Renner L, Stoddard J, Ryals R, Boulton ME, McGill T, Grant MB. Glial, Neuronal, Vascular, Retinal Pigment Epithelium, and Inflammatory Cell Damage in a New Western Diet-Induced Primate Model of Diabetic Retinopathy. THE AMERICAN JOURNAL OF PATHOLOGY 2023; 193:1789-1808. [PMID: 36965774 PMCID: PMC10616715 DOI: 10.1016/j.ajpath.2023.02.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 01/31/2023] [Accepted: 02/16/2023] [Indexed: 03/27/2023]
Abstract
This study investigated retinal changes in a Western diet (WD)-induced nonhuman primate model of type 2 diabetes. Rhesus nonhuman primates, aged 15 to 17 years, were fed a high-fat diet (n = 7) for >5 years reflective of the traditional WD. Age-matched controls (n = 6) were fed a standard laboratory primate diet. Retinal fundus photography, optical coherence tomography, autofluorescence imaging, and fluorescein angiography were performed before euthanasia. To assess diabetic retinopathy (DR), eyes were examined using trypsin digests, lipofuscin autofluorescence, and multimarker immunofluorescence on cross-sections and whole mounts. Retinal imaging showed venous engorgement and tortuosity, aneurysms, macular exudates, dot and blot hemorrhages, and a marked increase in fundus autofluorescence. Post-mortem changes included the following: decreased CD31 blood vessel density (P < 0.05); increased acellular capillaries (P < 0.05); increased density of ionized calcium-binding adaptor molecule expressing amoeboid microglia/macrophage; loss of regular distribution in stratum and spacing typical of ramified microglia; and increased immunoreactivity of aquaporin 4 and glial fibrillary acidic protein (P < 0.05). However, rhodopsin immunoreactivity (P < 0.05) in rods and neuronal nuclei antibody-positive neuronal density of 50% (P < 0.05) were decreased. This is the first report of a primate model of DR solely induced by a WD that replicates key features of human DR.
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Affiliation(s)
- Tailoi Chan-Ling
- Department of Anatomy, Faculty of Medicine and Health, Bosch Institute, University of Sydney, Camperdown, New South Wales, Australia.
| | - Ping Hu
- Department of Anatomy, Faculty of Medicine and Health, Bosch Institute, University of Sydney, Camperdown, New South Wales, Australia; Department of Ophthalmology and Visual Sciences, University of Alabama, Birmingham, Alabama
| | - Sergio Li Calzi
- Department of Ophthalmology and Visual Sciences, University of Alabama, Birmingham, Alabama
| | - Jeff Warner
- Department of Ophthalmology and Visual Sciences, University of Alabama, Birmingham, Alabama
| | - Nasir Uddin
- Department of Anatomy, Faculty of Medicine and Health, Bosch Institute, University of Sydney, Camperdown, New South Wales, Australia; Faculty of Science and Technology, Centre for Research in Therapeutic Solutions, University of Canberra, Bruce, Australian Capital Territory, Australia
| | - Mariana DuPont
- Department of Ophthalmology and Visual Sciences, University of Alabama, Birmingham, Alabama
| | - Martha Neuringer
- Department of Neuroscience, Oregon Health and Science University, Beaverton, Oregon
| | - Paul Kievit
- Division of Cardiometabolic Health, Oregon Health and Science University, Beaverton, Oregon
| | - Lauren Renner
- Department of Neuroscience, Oregon Health and Science University, Beaverton, Oregon
| | - Jonathan Stoddard
- Integrated Pathology Core, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, Oregon
| | - Renee Ryals
- Department of Ophthalmology, Oregon Health and Science University, Beaverton, Oregon
| | - Michael E Boulton
- Department of Ophthalmology and Visual Sciences, University of Alabama, Birmingham, Alabama
| | - Trevor McGill
- Department of Neuroscience, Oregon Health and Science University, Beaverton, Oregon
| | - Maria B Grant
- Department of Ophthalmology and Visual Sciences, University of Alabama, Birmingham, Alabama.
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8
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Nag TC. Müller cell vulnerability in aging human retina: Implications on photoreceptor cell survival. Exp Eye Res 2023; 235:109645. [PMID: 37683797 DOI: 10.1016/j.exer.2023.109645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 08/29/2023] [Accepted: 09/05/2023] [Indexed: 09/10/2023]
Abstract
Müller glial cells (MC) support various metabolic functions of the retinal neurons, and maintain the homeostasis. Oxidative stress is intensified with aging, and in human retina, MC and photoreceptors undergo lipid peroxidation and protein nitration. Information on how MC respond to oxidative stress is vital to understand the fate of aging retinal neurons. This study examined age-related changes in MC of donor human retina (age: 35-98 years; N = 18 donors). Ultrastructural and immunohistochemical observations indicate that MC undergo gliosis and increased lipid peroxidation, and show osmotic changes with advanced aging (>80 years). Photoreceptor cells also undergo oxidative-nitrosative stress with aging, and their synapses also show clear osmotic swelling. MC respond to oxidative stress via proliferation of smooth endoplasmic reticulum in their processes, and increased expression of aquaporin-4 in endfeet and outer retina. In advanced aged retinas (81-98 years), they showed mitochondrial disorganisation, accumulation of lipids and autophagosomes, lipofuscin granules and axonal remnants in phagolysosomes in their inner processes, suggesting a reduced phagocytotic potential in them with aging. Glutamine synthetase expression does not alter until advanced aging, when the retinas show its increased expression in endfeet and Henle fiber layer. It is evident that MC are vulnerable with normal aging and this could be a reason for photoreceptor cell abnormalities reported with aging of the human retina.
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Affiliation(s)
- Tapas C Nag
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi, India.
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9
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Cullen PF, Mazumder AG, Sun D, Flanagan JG. Rapid isolation of intact retinal astrocytes: a novel approach. Acta Neuropathol Commun 2023; 11:154. [PMID: 37749651 PMCID: PMC10521529 DOI: 10.1186/s40478-023-01641-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 08/23/2023] [Indexed: 09/27/2023] Open
Abstract
Astrocytes are a major category of glial support cell in the central nervous system and play a variety of essential roles in both health and disease. As our understanding of the diverse functions of these cells improves, the extent of heterogeneity between astrocyte populations has emerged as a key area of research. Retinal astrocytes, which form the direct cellular environment of retinal ganglion cells somas and axons, undergo a reactive response in both human glaucoma and animal models of the disease, yet their contributions to its pathology and progression remain relatively unknown. This gap in knowledge is largely a function of inadequate isolation techniques, driven in part by the sparseness of these cells and their similarities with the more abundant retinal Müller cells. Here, we present a novel method of isolating retinal astrocytes and enriching their RNA, tested in both normal and ocular hypertensive mice, a common model of experimental glaucoma. Our approach combines a novel enzyme assisted microdissection of retinal astrocytes with selective ribosome immunoprecipitation using the Ribotag method. Our microdissection method is rapid and preserves astrocyte morphology, resulting in a brief post-mortem interval and minimizing loss of RNA from distal regions of these cells. Both microdissection and Ribotag immunoprecipitation require a minimum of specialized equipment or reagents, and by using them in conjunction we are able to achieve > 100-fold enrichment of astrocyte RNA.
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Affiliation(s)
- Paul F Cullen
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, 02114, USA
| | - Arpan G Mazumder
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, 02114, USA
| | - Daniel Sun
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, 02114, USA.
| | - John G Flanagan
- Herbert Wertheim School of Optometry and Vision Science, University of California at Berkeley, Berkeley, CA, USA
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10
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Toader C, Tataru CP, Florian IA, Covache-Busuioc RA, Dumitrascu DI, Glavan LA, Costin HP, Bratu BG, Ciurea AV. From Homeostasis to Pathology: Decoding the Multifaceted Impact of Aquaporins in the Central Nervous System. Int J Mol Sci 2023; 24:14340. [PMID: 37762642 PMCID: PMC10531540 DOI: 10.3390/ijms241814340] [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: 09/02/2023] [Revised: 09/15/2023] [Accepted: 09/18/2023] [Indexed: 09/29/2023] Open
Abstract
Aquaporins (AQPs), integral membrane proteins facilitating selective water and solute transport across cell membranes, have been the focus of extensive research over the past few decades. Particularly noteworthy is their role in maintaining cellular homeostasis and fluid balance in neural compartments, as dysregulated AQP expression is implicated in various degenerative and acute brain pathologies. This article provides an exhaustive review on the evolutionary history, molecular classification, and physiological relevance of aquaporins, emphasizing their significance in the central nervous system (CNS). The paper journeys through the early studies of water transport to the groundbreaking discovery of Aquaporin 1, charting the molecular intricacies that make AQPs unique. It delves into AQP distribution in mammalian systems, detailing their selective permeability through permeability assays. The article provides an in-depth exploration of AQP4 and AQP1 in the brain, examining their contribution to fluid homeostasis. Furthermore, it elucidates the interplay between AQPs and the glymphatic system, a critical framework for waste clearance and fluid balance in the brain. The dysregulation of AQP-mediated processes in this system hints at a strong association with neurodegenerative disorders such as Parkinson's Disease, idiopathic normal pressure hydrocephalus, and Alzheimer's Disease. This relationship is further explored in the context of acute cerebral events such as stroke and autoimmune conditions such as neuromyelitis optica (NMO). Moreover, the article scrutinizes AQPs at the intersection of oncology and neurology, exploring their role in tumorigenesis, cell migration, invasiveness, and angiogenesis. Lastly, the article outlines emerging aquaporin-targeted therapies, offering a glimpse into future directions in combatting CNS malignancies and neurodegenerative diseases.
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Affiliation(s)
- Corneliu Toader
- Department of Neurosurgery, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania; (C.T.); (R.-A.C.-B.); (D.-I.D.); (L.A.G.); (H.P.C.); (B.-G.B.); (A.V.C.)
- Department of Vascular Neurosurgery, National Institute of Neurology and Neurovascular Diseases, 077160 Bucharest, Romania
| | - Calin Petru Tataru
- Department of Opthamology, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania
- Central Military Emergency Hospital “Dr. Carol Davila”, 010825 Bucharest, Romania
| | - Ioan-Alexandru Florian
- Department of Neurosciences, “Iuliu Hatieganu” University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
| | - Razvan-Adrian Covache-Busuioc
- Department of Neurosurgery, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania; (C.T.); (R.-A.C.-B.); (D.-I.D.); (L.A.G.); (H.P.C.); (B.-G.B.); (A.V.C.)
| | - David-Ioan Dumitrascu
- Department of Neurosurgery, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania; (C.T.); (R.-A.C.-B.); (D.-I.D.); (L.A.G.); (H.P.C.); (B.-G.B.); (A.V.C.)
| | - Luca Andrei Glavan
- Department of Neurosurgery, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania; (C.T.); (R.-A.C.-B.); (D.-I.D.); (L.A.G.); (H.P.C.); (B.-G.B.); (A.V.C.)
| | - Horia Petre Costin
- Department of Neurosurgery, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania; (C.T.); (R.-A.C.-B.); (D.-I.D.); (L.A.G.); (H.P.C.); (B.-G.B.); (A.V.C.)
| | - Bogdan-Gabriel Bratu
- Department of Neurosurgery, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania; (C.T.); (R.-A.C.-B.); (D.-I.D.); (L.A.G.); (H.P.C.); (B.-G.B.); (A.V.C.)
| | - Alexandru Vlad Ciurea
- Department of Neurosurgery, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania; (C.T.); (R.-A.C.-B.); (D.-I.D.); (L.A.G.); (H.P.C.); (B.-G.B.); (A.V.C.)
- Neurosurgery Department, Sanador Clinical Hospital, 010991 Bucharest, Romania
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11
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Wolf HN, Ehinger V, Guempelein L, Banerjee P, Kuempfel T, Havla J, Pauly D. NMOSD IgG Impact Retinal Cells in Murine Retinal Explants. Curr Issues Mol Biol 2023; 45:7319-7335. [PMID: 37754247 PMCID: PMC10529972 DOI: 10.3390/cimb45090463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 08/29/2023] [Accepted: 09/05/2023] [Indexed: 09/28/2023] Open
Abstract
Neuromyelitis optica spectrum disorders (NMOSD) are chronic inflammatory diseases of the central nervous system, characterized by autoantibodies against aquaporin-4. The symptoms primarily involve severe optic neuritis and longitudinally extensive transverse myelitis. Although the disease progression is typically relapse-dependent, recent studies revealed retinal neuroaxonal degeneration unrelated to relapse activity, potentially due to anti-aquaporin-4-positive antibodies interacting with retinal glial cells such as Müller cells. In this exploratory study, we analysed the response of mouse retinal explants to NMOSD immunoglobulins (IgG). Mouse retinal explants were treated with purified IgG from patient or control sera for one and three days. We characterized tissue response patterns through morphological changes, chemokine secretion, and complement expression. Mouse retinal explants exhibited a basic proinflammatory response ex vivo, modified by IgG addition. NMOSD IgG, unlike control IgG, increased gliosis and decreased chemokine release (CCL2, CCL3, CCL4, and CXCL-10). Complement component expression by retinal cells remained unaltered by either IgG fraction. We conclude that human NMOSD IgG can possibly bind in the mouse retina, altering the local cellular environment. This intraretinal stress may contribute to retinal degeneration independent of relapse activity in NMOSD, suggesting a primary retinopathy.
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Affiliation(s)
- Hannah Nora Wolf
- Department of Experimental Ophthalmology, University Marburg, 35037 Marburg, Germany
| | - Veronika Ehinger
- Department of Experimental Ophthalmology, University Marburg, 35037 Marburg, Germany
| | - Larissa Guempelein
- Department of Experimental Ophthalmology, University Marburg, 35037 Marburg, Germany
| | - Pratiti Banerjee
- Department of Experimental Ophthalmology, University Marburg, 35037 Marburg, Germany
| | - Tania Kuempfel
- Institute of Clinical Neuroimmunology, Biomedical Center and University Hospital, Ludwig-Maximilians-Universität München, 81377 Munich, Germany
| | - Joachim Havla
- Institute of Clinical Neuroimmunology, Biomedical Center and University Hospital, Ludwig-Maximilians-Universität München, 81377 Munich, Germany
| | - Diana Pauly
- Department of Experimental Ophthalmology, University Marburg, 35037 Marburg, Germany
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12
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Ramsay E, Lajunen T, Bhattacharya M, Reinisalo M, Rilla K, Kidron H, Terasaki T, Urtti A. Selective drug delivery to the retinal cells: Biological barriers and avenues. J Control Release 2023; 361:1-19. [PMID: 37481214 DOI: 10.1016/j.jconrel.2023.07.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 06/09/2023] [Accepted: 07/16/2023] [Indexed: 07/24/2023]
Abstract
Retinal drug delivery is a challenging, but important task, because most retinal diseases are still without any proper therapy. Drug delivery to the retina is hampered by the anatomical and physiological barriers resulting in minimal bioavailability after topical ocular and systemic administrations. Intravitreal injections are current method-of-choice in retinal delivery, but these injections show short duration of action for small molecules and low target bioavailability for many protein, gene based drugs and nanomedicines. State-of-art delivery systems are based on prolonged retention, controlled drug release and physical features (e.g. size and charge). However, drug delivery to the retina is not cell-specific and these approaches do not facilitate intracellular delivery of modern biological drugs (e.g. intracellular proteins, RNA based medicines, gene editing). In this focused review we highlight biological factors and mechanisms that form the basis for the selective retinal drug delivery systems in the future. Therefore, we are presenting current knowledge related to retinal membrane transporters, receptors and targeting ligands in relation to nanomedicines, conjugates, extracellular vesicles, and melanin binding. These issues are discussed in the light of retinal structure and cell types as well as future prospects in the field. Unlike in some other fields of targeted drug delivery (e.g. cancer research), selective delivery technologies have been rarely studied, even though cell targeted delivery may be even more feasible after local administration into the eye.
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Affiliation(s)
- Eva Ramsay
- Drug Research Programme, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, 00014 University of Helsinki, Finland
| | - Tatu Lajunen
- Drug Research Programme, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, 00014 University of Helsinki, Finland; School of Pharmacy, University of Eastern Finland, Yliopistonranta 1 C, 70211 Kuopio, Finland
| | - Madhushree Bhattacharya
- Drug Research Programme, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, 00014 University of Helsinki, Finland
| | - Mika Reinisalo
- School of Pharmacy, University of Eastern Finland, Yliopistonranta 1 C, 70211 Kuopio, Finland
| | - Kirsi Rilla
- School of Medicine, University of Eastern Finland, Yliopistonranta 1 C, 70211 Kuopio, Finland
| | - Heidi Kidron
- Drug Research Programme, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, 00014 University of Helsinki, Finland
| | - Tetsuya Terasaki
- School of Pharmacy, University of Eastern Finland, Yliopistonranta 1 C, 70211 Kuopio, Finland
| | - Arto Urtti
- Drug Research Programme, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, 00014 University of Helsinki, Finland; School of Pharmacy, University of Eastern Finland, Yliopistonranta 1 C, 70211 Kuopio, Finland.
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13
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Pechlivanidou M, Xenou K, Tzanetakos D, Koutsos E, Stergiou C, Andreadou E, Voumvourakis K, Giannopoulos S, Kilidireas C, Tüzün E, Tsivgoulis G, Tzartos S, Tzartos J. Potential Role of Antibodies against Aquaporin-1 in Patients with Central Nervous System Demyelination. Int J Mol Sci 2023; 24:12982. [PMID: 37629163 PMCID: PMC10455752 DOI: 10.3390/ijms241612982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 08/09/2023] [Accepted: 08/17/2023] [Indexed: 08/27/2023] Open
Abstract
Aquaporins (AQPs; AQP0-AQP12) are water channels expressed in many and diverse cell types, participating in various functions of cells, tissues, and systems, including the central nervous system (CNS). AQP dysfunction and autoimmunity to AQPs are implicated in several diseases. The best-known example of autoimmunity against AQPs concerns the antibodies to AQP4 which are involved in the pathogenesis of neuromyelitis optica spectrum disorder (NMOSD), an autoimmune astrocytopathy, causing also CNS demyelination. The present review focuses on the discovery and the potential role of antibodies against AQP1 in the CNS, and their potential involvement in the pathophysiology of NMOSD. We describe (a) the several techniques developed for the detection of the AQP1-antibodies, with emphasis on methods that specifically identify antibodies targeting the extracellular domain of AQP1, i.e., those of potential pathogenic role, and (b) the available evidence supporting the pathogenic relevance of AQP1-antibodies in the NMOSD phenotype.
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Affiliation(s)
- Maria Pechlivanidou
- Tzartos NeuroDiagnostics, 11523 Athens, Greece; (M.P.); (K.X.); (E.K.); (C.S.); (S.T.)
| | - Konstantina Xenou
- Tzartos NeuroDiagnostics, 11523 Athens, Greece; (M.P.); (K.X.); (E.K.); (C.S.); (S.T.)
| | - Dimitrios Tzanetakos
- Second Department of Neurology ‘’Attikon’’ University Hospital, School of Medicine, National & Kapodistrian University of Athens, 12462 Athens, Greece; (D.T.); (K.V.); (S.G.); (G.T.)
| | - Emmanuel Koutsos
- Tzartos NeuroDiagnostics, 11523 Athens, Greece; (M.P.); (K.X.); (E.K.); (C.S.); (S.T.)
| | - Christos Stergiou
- Tzartos NeuroDiagnostics, 11523 Athens, Greece; (M.P.); (K.X.); (E.K.); (C.S.); (S.T.)
| | - Elisabeth Andreadou
- First Department of Neurology, ‘’Aiginiteion’’ University Hospital, National and Kapodistrian University of Athens, 11528 Athens, Greece; (E.A.); (C.K.)
| | - Konstantinos Voumvourakis
- Second Department of Neurology ‘’Attikon’’ University Hospital, School of Medicine, National & Kapodistrian University of Athens, 12462 Athens, Greece; (D.T.); (K.V.); (S.G.); (G.T.)
| | - Sotirios Giannopoulos
- Second Department of Neurology ‘’Attikon’’ University Hospital, School of Medicine, National & Kapodistrian University of Athens, 12462 Athens, Greece; (D.T.); (K.V.); (S.G.); (G.T.)
| | - Constantinos Kilidireas
- First Department of Neurology, ‘’Aiginiteion’’ University Hospital, National and Kapodistrian University of Athens, 11528 Athens, Greece; (E.A.); (C.K.)
- Second Department of Neurology, Henry Dunant Hospital Center, 11526 Athens, Greece
| | - Erdem Tüzün
- Department of Neuroscience, Aziz Sancar Institute of Experimental Medicine, Istanbul University, 34093 Istanbul, Turkey;
| | - Georgios Tsivgoulis
- Second Department of Neurology ‘’Attikon’’ University Hospital, School of Medicine, National & Kapodistrian University of Athens, 12462 Athens, Greece; (D.T.); (K.V.); (S.G.); (G.T.)
| | - Socrates Tzartos
- Tzartos NeuroDiagnostics, 11523 Athens, Greece; (M.P.); (K.X.); (E.K.); (C.S.); (S.T.)
- Department of Neurobiology, Hellenic Pasteur Institute, 11521 Athens, Greece
- Department of Pharmacy, University of Patras, 26504 Patras, Greece
| | - John Tzartos
- Second Department of Neurology ‘’Attikon’’ University Hospital, School of Medicine, National & Kapodistrian University of Athens, 12462 Athens, Greece; (D.T.); (K.V.); (S.G.); (G.T.)
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14
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Menean M, Sacconi R, Vujosevic S, Kesim C, Quarta A, Ribarich N, Bottazzi L, Hilely A, Capuano V, Souied EH, Sarraf D, Bandello F, Querques G. Subretinal Pseudocysts: A Comprehensive Analysis of this Novel OCT Finding. Ophthalmol Ther 2023; 12:2035-2048. [PMID: 37198519 PMCID: PMC10287866 DOI: 10.1007/s40123-023-00727-8] [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: 12/31/2022] [Accepted: 04/27/2023] [Indexed: 05/19/2023] Open
Abstract
INTRODUCTION In current clinical practice, several optical coherence tomography (OCT) biomarkers have been proposed for the assessment of severity and prognosis of different retinal diseases. Subretinal pseudocysts are subretinal cystoid spaces with hyperreflective borders and only a few single cases have been reported thus far. The aim of the study was to characterize and investigate this novel OCT finding, exploring its clinical outcome. METHODS Patients were evaluated retrospectively across different centers. The inclusion criterion was the presence of subretinal cystoid space on OCT scans, regardless of concurrent retinal diseases. Baseline examination was set as the first time the subretinal pseudocyst was identified by OCT. Medical and ophthalmological histories were collected at baseline. OCT and OCT-angiography were performed at baseline and at each follow-up examination. RESULTS Twenty-eight eyes were included in the study and 31 subretinal pseudocysts were characterized. Out of 28 eyes, 16 were diagnosed with neovascular age-related macular degeneration (AMD), 7 with central serous chorioretinopathy, 4 with diabetic retinopathy, and 1 with angioid streaks. Subretinal and intraretinal fluid were present in 25 and 13 eyes, respectively. Mean distance of the subretinal pseudocyst from the fovea was 686 µm. The diameter of the pseudocyst was positively associated with the height of the subretinal fluid (r = 0.46; p = 0.018) and central macular thickness (r = 0.612; p = 0.001). At follow-up, subretinal pseudocysts disappeared in most of the reimaged eyes (16 out of 17). Of these, two patients presented retinal atrophy at baseline examination and eight patients (47%) developed retinal atrophy at follow-up. Conversely, seven eyes (41%) did not develop retinal atrophy. CONCLUSION Subretinal pseudocysts are precarious OCT findings, usually disclosed in a context of subretinal fluid, and are probably transient alterations within the photoreceptor outer segments and retinal pigment epithelium (RPE) layer. Despite their nature, subretinal pseudocysts have been associated with photoreceptor loss and incomplete RPE definition.
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Affiliation(s)
- Matteo Menean
- School of Medicine, Vita-Salute San Raffaele University, Milan, Italy
- Division of Head and Neck, Ophthalmology Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy
- Department of Ophthalmology, University Vita-Salute, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Riccardo Sacconi
- School of Medicine, Vita-Salute San Raffaele University, Milan, Italy
- Division of Head and Neck, Ophthalmology Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy
- Department of Ophthalmology, University Vita-Salute, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Stela Vujosevic
- Medical Retina Service, University Hospital "Maggiore Della Carità", Novara, Italy
- Department of Biomedical, Surgical and Dental Sciences, University of Milan, Milan, Italy
| | - Cem Kesim
- Department of Ophthalmology, Koç University School of Medicine, Istanbul, Turkey
| | - Alberto Quarta
- Department of Medicine and Science of Ageing, Ophthalmology Clinic, University G. D'Annunzio Chieti-Pescara, Via Dei Vestini 31, 66100, Chieti, Italy
| | - Nicolò Ribarich
- School of Medicine, Vita-Salute San Raffaele University, Milan, Italy
- Division of Head and Neck, Ophthalmology Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy
- Department of Ophthalmology, University Vita-Salute, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Leonardo Bottazzi
- School of Medicine, Vita-Salute San Raffaele University, Milan, Italy
- Division of Head and Neck, Ophthalmology Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy
- Department of Ophthalmology, University Vita-Salute, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Assaf Hilely
- Retinal Disorders and Ophthalmic Genetics Division, Stein Eye Institute, University of California, Los Angeles, CA, USA
- Greater Los Angeles VA Healthcare Center, Los Angeles, CA, USA
| | - Vittorio Capuano
- Department of Ophthalmology, Hospital Intercommunal de Creteil, University Paris Est Creteil, Creteil, France
| | - Eric H Souied
- Department of Ophthalmology, Hospital Intercommunal de Creteil, University Paris Est Creteil, Creteil, France
| | - David Sarraf
- Retinal Disorders and Ophthalmic Genetics Division, Stein Eye Institute, University of California, Los Angeles, CA, USA
- Greater Los Angeles VA Healthcare Center, Los Angeles, CA, USA
| | - Francesco Bandello
- School of Medicine, Vita-Salute San Raffaele University, Milan, Italy
- Division of Head and Neck, Ophthalmology Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy
- Department of Ophthalmology, University Vita-Salute, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Giuseppe Querques
- School of Medicine, Vita-Salute San Raffaele University, Milan, Italy.
- Division of Head and Neck, Ophthalmology Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy.
- Department of Ophthalmology, University Vita-Salute, IRCCS Ospedale San Raffaele, Milan, Italy.
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15
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Cullen PF, Sun D. Astrocytes of the eye and optic nerve: heterogeneous populations with unique functions mediate axonal resilience and vulnerability to glaucoma. FRONTIERS IN OPHTHALMOLOGY 2023; 3:1217137. [PMID: 37829657 PMCID: PMC10569075 DOI: 10.3389/fopht.2023.1217137] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/14/2023]
Abstract
The role of glia, particularly astrocytes, in mediating the central nervous system's response to injury and neurodegenerative disease is an increasingly well studied topic. These cells perform myriad support functions under physiological conditions but undergo behavioral changes - collectively referred to as 'reactivity' - in response to the disruption of neuronal homeostasis from insults, including glaucoma. However, much remains unknown about how reactivity alters disease progression - both beneficially and detrimentally - and whether these changes can be therapeutically modulated to improve outcomes. Historically, the heterogeneity of astrocyte behavior has been insufficiently addressed under both physiological and pathological conditions, resulting in a fragmented and often contradictory understanding of their contributions to health and disease. Thanks to increased focus in recent years, we now know this heterogeneity encompasses both intrinsic variation in physiological function and insult-specific changes that vary between pathologies. Although previous studies demonstrate astrocytic alterations in glaucoma, both in human disease and animal models, generally these findings do not conclusively link astrocytes to causative roles in neuroprotection or degeneration, rather than a subsequent response. Efforts to bolster our understanding by drawing on knowledge of brain astrocytes has been constrained by the primacy in the literature of findings from peri-synaptic 'gray matter' astrocytes, whereas much early degeneration in glaucoma occurs in axonal regions populated by fibrous 'white matter' astrocytes. However, by focusing on findings from astrocytes of the anterior visual pathway - those of the retina, unmyelinated optic nerve head, and myelinated optic nerve regions - we aim to highlight aspects of their behavior that may contribute to axonal vulnerability and glaucoma progression, including roles in mitochondrial turnover and energy provisioning. Furthermore, we posit that astrocytes of the retina, optic nerve head and myelinated optic nerve, although sharing developmental origins and linked by a network of gap junctions, may be best understood as distinct populations residing in markedly different niches with accompanying functional specializations. A closer investigation of their behavioral repertoires may elucidate not only their role in glaucoma, but also mechanisms to induce protective behaviors that can impede the progressive axonal damage and retinal ganglion cell death that drive vision loss in this devastating condition.
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Affiliation(s)
- Paul F. Cullen
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, United States
| | - Daniel Sun
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, United States
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16
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Gao Y, Liu K, Zhu J. Glymphatic system: an emerging therapeutic approach for neurological disorders. Front Mol Neurosci 2023; 16:1138769. [PMID: 37485040 PMCID: PMC10359151 DOI: 10.3389/fnmol.2023.1138769] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 06/21/2023] [Indexed: 07/25/2023] Open
Abstract
The functions of the glymphatic system include clearance of the metabolic waste and modulation of the water transport in the brain, and it forms a brain-wide fluid network along with cerebrospinal fluid (CSF) and interstitial fluid (ISF). The glymphatic pathway consists of periarterial influx of CSF, astrocyte-mediated interchange between ISF and CSF supported by aquaporin-4 (AQP4) on the endfeet of astrocyte around the periarterioles, and perivenous efflux of CSF. Finally, CSF is absorbed by the arachnoid granules or flows into the cervical lymphatic vessels. There is growing evidence from animal experiments that the glymphatic system dysfunction is involved in many neurological disorders, such as Alzheimer's disease, stroke, epilepsy, traumatic brain injury and meningitis. In this review, we summarize the latest progress on the glymphatic system and its driving factors, as well as changes in the glymphatic pathway in different neurological diseases. We significantly highlight the likely therapeutic approaches for glymphatic pathway in neurological diseases, and the importance of AQP4 and normal sleep architecture in this process.
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Affiliation(s)
- Ying Gao
- Department of Neurology, Neuroscience Centre, The First Hospital of Jilin University, Changchun, China
| | - Kangding Liu
- Department of Neurology, Neuroscience Centre, The First Hospital of Jilin University, Changchun, China
| | - Jie Zhu
- Department of Neurology, Neuroscience Centre, The First Hospital of Jilin University, Changchun, China
- Department of Neurobiology, Care Sciences and Society, Karolinska Institute, Karolinska University Hospital, Solna, Sweden
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17
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Xingi E, Koutsoudaki PN, Thanou I, Phan MS, Margariti M, Scheller A, Tinevez JY, Kirchhoff F, Thomaidou D. LPS-Induced Systemic Inflammation Affects the Dynamic Interactions of Astrocytes and Microglia with the Vasculature of the Mouse Brain Cortex. Cells 2023; 12:1418. [PMID: 37408252 DOI: 10.3390/cells12101418] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 05/05/2023] [Accepted: 05/13/2023] [Indexed: 07/07/2023] Open
Abstract
The Neurovascular Unit (NVU), composed of glia (astrocytes, oligodendrocytes, microglia), neurons, pericytes and endothelial cells, is a dynamic interface ensuring the physiological functioning of the central nervous system (CNS), which gets affected and contributes to the pathology of several neurodegenerative diseases. Neuroinflammation is a common feature of neurodegenerative diseases and is primarily related to the activation state of perivascular microglia and astrocytes, which constitute two of its major cellular components. Our studies focus on monitoring in real time the morphological changes of perivascular astrocytes and microglia, as well as their dynamic interactions with the brain vasculature, under physiological conditions and following systemic neuroinflammation triggering both microgliosis and astrogliosis. To this end, we performed 2-photon laser scanning microscopy (2P-LSM) for intravital imaging of the cortex of transgenic mice visualizing the dynamics of microglia and astroglia following neuroinflammation induced by systemic administration of the endotoxin lipopolysaccharide (LPS). Our results indicate that following neuroinflammation the endfeet of activated perivascular astrocytes lose their close proximity and physiological cross-talk with vasculature, an event that most possibly contributes to a loss of blood-brain barrier (BBB) integrity. At the same time, microglial cells become activated and exhibit a higher extent of physical contact with the blood vessels. These dynamic responses of perivascular astrocytes and microglia are peaking at 4 days following LPS administration; however, they still persist at a lower level at 8 days after LPS injection, revealing incomplete reversal of inflammation affecting the glial properties and interactions within the NVU.
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Affiliation(s)
- Evangelia Xingi
- Light Microscopy Unit, Hellenic Pasteur Institute, 11521 Athens, Greece
| | - Paraskevi N Koutsoudaki
- Neural Stem Cells and Neuroimaging Group, Department of Neurobiology, Hellenic Pasteur Institute, 11521 Athens, Greece
| | - Irini Thanou
- Neural Stem Cells and Neuroimaging Group, Department of Neurobiology, Hellenic Pasteur Institute, 11521 Athens, Greece
| | - Minh-Son Phan
- Institut Pasteur, Université de Paris, Image Analysis Hub, F-75015 Paris, France
| | - Maria Margariti
- Neural Stem Cells and Neuroimaging Group, Department of Neurobiology, Hellenic Pasteur Institute, 11521 Athens, Greece
| | - Anja Scheller
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, 66421 Homburg, Germany
| | - Jean-Yves Tinevez
- Institut Pasteur, Université de Paris, Image Analysis Hub, F-75015 Paris, France
| | - Frank Kirchhoff
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, 66421 Homburg, Germany
| | - Dimitra Thomaidou
- Light Microscopy Unit, Hellenic Pasteur Institute, 11521 Athens, Greece
- Neural Stem Cells and Neuroimaging Group, Department of Neurobiology, Hellenic Pasteur Institute, 11521 Athens, Greece
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18
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Formolo DA, Yu J, Lin K, Tsang HWH, Ou H, Kranz GS, Yau SY. Leveraging the glymphatic and meningeal lymphatic systems as therapeutic strategies in Alzheimer's disease: an updated overview of nonpharmacological therapies. Mol Neurodegener 2023; 18:26. [PMID: 37081555 PMCID: PMC10116684 DOI: 10.1186/s13024-023-00618-3] [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: 08/29/2022] [Accepted: 04/05/2023] [Indexed: 04/22/2023] Open
Abstract
Understanding and treating Alzheimer's disease (AD) has been a remarkable challenge for both scientists and physicians. Although the amyloid-beta and tau protein hypothesis have largely explained the key pathological features of the disease, the mechanisms by which such proteins accumulate and lead to disease progression are still unknown. Such lack of understanding disrupts the development of disease-modifying interventions, leaving a therapeutic gap that remains unsolved. Nonetheless, the recent discoveries of the glymphatic pathway and the meningeal lymphatic system as key components driving central solute clearance revealed another mechanism underlying AD pathogenesis. In this regard, this narrative review integrates the glymphatic and meningeal lymphatic systems as essential components involved in AD pathogenesis. Moreover, it discusses the emerging evidence suggesting that nutritional supplementation, non-invasive brain stimulation, and traditional Chinese medicine can improve the pathophysiology of the disease by increasing glymphatic and/or meningeal lymphatic function. Given that physical exercise is a well-regarded preventive and pro-cognitive intervention for dementia, we summarize the evidence suggesting the glymphatic system as a mediating mechanism of the physical exercise therapeutic effects in AD. Targeting these central solute clearance systems holds the promise of more effective treatment strategies.
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Affiliation(s)
- Douglas A Formolo
- Department of Rehabilitation Sciences, Faculty of Health and Social Sciences, The Hong Kong Polytechnic University, 11 Yuk Choi Road, Hung Hom, Kowloon, Hong Kong, S.A.R, China
- Research Institute for Smart Ageing (RISA), The Hong Kong Polytechnic University, Hong Kong S.A.R, China
- Mental Health Research Center (MHRC), The Hong Kong Polytechnic University, Hong Kong S.A.R, China
| | - Jiasui Yu
- Department of Rehabilitation Sciences, Faculty of Health and Social Sciences, The Hong Kong Polytechnic University, 11 Yuk Choi Road, Hung Hom, Kowloon, Hong Kong, S.A.R, China
- Research Institute for Smart Ageing (RISA), The Hong Kong Polytechnic University, Hong Kong S.A.R, China
- Mental Health Research Center (MHRC), The Hong Kong Polytechnic University, Hong Kong S.A.R, China
| | - Kangguang Lin
- Department of Affective Disorders, The Affiliated Brain Hospital of Guangzhou Medical University, Guangzhou, Guangdong Province, China
- School of Health and Life Sciences, University of Health and Rehabilitation Sciences, Qingdao City, Shandong Province, China
| | - Hector W H Tsang
- Department of Rehabilitation Sciences, Faculty of Health and Social Sciences, The Hong Kong Polytechnic University, 11 Yuk Choi Road, Hung Hom, Kowloon, Hong Kong, S.A.R, China
- Mental Health Research Center (MHRC), The Hong Kong Polytechnic University, Hong Kong S.A.R, China
| | - Haining Ou
- Department of Rehabilitation, The Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong Province, China
| | - Georg S Kranz
- Department of Rehabilitation Sciences, Faculty of Health and Social Sciences, The Hong Kong Polytechnic University, 11 Yuk Choi Road, Hung Hom, Kowloon, Hong Kong, S.A.R, China
- Mental Health Research Center (MHRC), The Hong Kong Polytechnic University, Hong Kong S.A.R, China
- Department of Psychiatry and Psychotherapy, Comprehensive Center for Clinical Neurosciences and Mental Health (C3NMH), Medical University of Vienna, Vienna, Austria
- The State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong S.A.R, China
| | - Suk-Yu Yau
- Department of Rehabilitation Sciences, Faculty of Health and Social Sciences, The Hong Kong Polytechnic University, 11 Yuk Choi Road, Hung Hom, Kowloon, Hong Kong, S.A.R, China.
- Research Institute for Smart Ageing (RISA), The Hong Kong Polytechnic University, Hong Kong S.A.R, China.
- Mental Health Research Center (MHRC), The Hong Kong Polytechnic University, Hong Kong S.A.R, China.
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19
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Eastlake K, Luis J, Wang W, Lamb W, Khaw PT, Limb GA. Transcriptomics of CD29 +/CD44 + cells isolated from hPSC retinal organoids reveals a single cell population with retinal progenitor and Müller glia characteristics. Sci Rep 2023; 13:5081. [PMID: 36977817 PMCID: PMC10050419 DOI: 10.1038/s41598-023-32058-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 03/21/2023] [Indexed: 03/30/2023] Open
Abstract
Müller glia play very important and diverse roles in retinal homeostasis and disease. Although much is known of the physiological and morphological properties of mammalian Müller glia, there is still the need to further understand the profile of these cells during human retinal development. Using human embryonic stem cell-derived retinal organoids, we investigated the transcriptomic profiles of CD29+/CD44+ cells isolated from early and late stages of organoid development. Data showed that these cells express classic markers of retinal progenitors and Müller glia, including NFIX, RAX, PAX6, VSX2, HES1, WNT2B, SOX, NR2F1/2, ASCL1 and VIM, as early as days 10-20 after initiation of retinal differentiation. Expression of genes upregulated in CD29+/CD44+ cells isolated at later stages of organoid development (days 50-90), including NEUROG1, VSX2 and ASCL1 were gradually increased as retinal organoid maturation progressed. Based on the current observations that CD24+/CD44+ cells share the characteristics of early and late-stage retinal progenitors as well as of mature Müller glia, we propose that these cells constitute a single cell population that upon exposure to developmental cues regulates its gene expression to adapt to functions exerted by Müller glia in the postnatal and mature retina.
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Affiliation(s)
- Karen Eastlake
- NIHR Biomedical Research Centre at Moorfields Eye Hospital, UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL, UK.
| | - Joshua Luis
- NIHR Biomedical Research Centre at Moorfields Eye Hospital, UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL, UK
| | - Weixin Wang
- NIHR Biomedical Research Centre at Moorfields Eye Hospital, UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL, UK
| | - William Lamb
- NIHR Biomedical Research Centre at Moorfields Eye Hospital, UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL, UK
| | - Peng T Khaw
- NIHR Biomedical Research Centre at Moorfields Eye Hospital, UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL, UK
| | - G Astrid Limb
- NIHR Biomedical Research Centre at Moorfields Eye Hospital, UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL, UK.
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Huang L, Wang Y, Zhang R. Retina thickness in clinically affected and unaffected eyes in patients with aquaporin-4 immunoglobulin G antibody seropositive neuromyelitis optica spectrum disorders: a systematic review and meta-analysis. J Neurol 2023; 270:759-768. [PMID: 36355186 DOI: 10.1007/s00415-022-11482-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Revised: 11/04/2022] [Accepted: 11/05/2022] [Indexed: 11/11/2022]
Abstract
BACKGROUND AND PURPOSE Retina thickness has been studied in patients with neuromyelitis optica spectrum disorders (NMOSD) without distinguishing serostatus and limited data are available in unaffected eyes. We aimed to investigate retina thickness in eyes of aquaporin-4 immunoglobulin G antibody seropositive (AQP4-IgG+) NMOSD patients with optic neuritis (AQP4-ON) and without (AQP4-NON). METHODS Eligible studies were identified by searching PubMed and Embase. Mean difference (MD, μm) with corresponding 95% confidence interval (CI) was pooled with random-effect models. The primary measures were average thickness of peripapillar retinal nerve fiber layer (pRNFL) centered on optic disc and the combination of ganglion cell layer and inner plexiform layer (GCIPL) at macula. RESULTS We included 21 studies enrolling 787 AQP4-IgG+ NMOSD patients. Compared with healthy control, pRNFL was thinner in eyes of AQP4-ON (- 32.78, 95% CI [- 36.24, - 29.33]) and AQP4-NON (- 2.76, 95% CI [- 3.94, - 1.58]), so was GICPL in AQP4-ON (-21.38, 95% CI [- 24.01, - 18.74]) and AQP4-NON (95% CI - 2.96, [- 3.91, - 2.00]). Compared with multiple sclerosis with ON, AQP4-ON had thinner pRNFL (- 13.56, 95%CI [- 16.51, - 10.60]) and GCIPL (- 9.12, 95% CI [- 11.88, - 6.36]). AQP4-ON and myelin oligodendrocyte glycoprotein antibody-associated demyelination with ON (MOG-ON) had similar pRNFL (0.59, 95% CI [- 6.61, 7.79]) and GCIPL thickness (- 0.55, 95% CI [- 2.92, 1.82]). AQP4-NON had similar pRNFL and GCIPL thickness to MOG-NON and multiple sclerosis without ON. CONCLUSIONS The average thickness of pRNFL and GICPL decreased both in AQP4-ON and AQP4-NON eyes. AQP4-ON eyes had a similar level of pRNFL and GICPL thinning to MOG-ON eyes, so did AQP4-NON to MOG-NON eyes.
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Affiliation(s)
- Lele Huang
- Department of Ophthalmology, The First Hospital of China Medical University, 155 Nanjingbei Street, Heping District, Shenyang, 110001, People's Republic of China
| | - Yujie Wang
- Department of Neurology, People's Hospital, China Medical University, 33 Wenyi Road, Shenhe District, Shenyang, 110016, People's Republic of China
| | - Ruijun Zhang
- Department of Ophthalmology, The First Hospital of China Medical University, 155 Nanjingbei Street, Heping District, Shenyang, 110001, People's Republic of China.
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Aquaporin-1 and Aquaporin-4 Expression in Ependyma, Choroid Plexus and Surrounding Transition Zones in the Human Brain. Biomolecules 2023; 13:biom13020212. [PMID: 36830582 PMCID: PMC9953559 DOI: 10.3390/biom13020212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 01/18/2023] [Accepted: 01/19/2023] [Indexed: 01/25/2023] Open
Abstract
The choroid plexus (CP) is a structure in the brain ventricles that produces the main part of the cerebrospinal fluid (CSF). It is covered with specialized cells which show epithelial characteristics and are the site of the blood-CSF barrier. These cells form a contiguous cell sheet with ventricle-lining ependymal cells which are known to express aquaporin-4 (AQP4). In contrast, CP epithelial cells express aquaporin-1 (AQP1) apically. We investigated the expression patterns of aquaporins in the CP-ependyma transition from human body donors using immunofluorescence and electron microscopy. Ependymal cells and subependymal astrocytes at the base of the CP showed a particularly high AQP4 immunoreactivity. Astrocytic processes formed a dense meshwork or glial plate around the blood vessels entering the CP. Interestingly, some of these astrocytic processes were in direct contact with the CP stroma, which contains fenestrated blood vessels, separated only by a basal lamina. Electron microscopy confirmed the continuity of the subastrocytic basal lamina with the CP epithelium. We also probed for components of the AQP4 anchoring dystrophin-dystroglycan complex. Immunolabeling for dystrophin and AQP4 showed an overlapping staining pattern in the glial plate but not in previously reported AQP4-positive CP epithelial cells. In contrast, dystroglycan expression was associated with laminin staining in the glial plate and the CP epithelium. This suggests different mechanisms for AQP4 anchoring in the cell membrane. The high AQP4 density in the connecting glial plate might facilitate the transport of water in and out of the CP stroma and could possibly serve as a drainage and clearing pathway for metabolites.
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Wostyn P, Killer HE. Normal-Tension Glaucoma: A Glymphopathy? Eye Brain 2023; 15:37-44. [PMID: 37056720 PMCID: PMC10086217 DOI: 10.2147/eb.s401306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Accepted: 03/07/2023] [Indexed: 04/15/2023] Open
Abstract
Glaucoma is one of the main causes of irreversible blindness in the world. The most common form, primary open-angle glaucoma, is an optic neuropathy that is characterized by a progressive loss of retinal ganglion cells and their axons, leading to structural changes in the optic nerve head and associated visual field defects. Elevated intraocular pressure remains the most important modifiable risk factor for primary open-angle glaucoma. However, a significant proportion of patients develop glaucomatous damage in the absence of increased intraocular pressure, a condition known as normal-tension glaucoma (NTG). The pathophysiology underlying NTG remains unclear. Several studies have revealed that vascular and cerebrospinal fluid (CSF) factors may play significant roles in the development of NTG. Vascular failure caused by functional or structural abnormalities, and compartmentation of the optic nerve subarachnoid space with disturbed CSF dynamics have been shown to be associated with NTG. In the present article, based on the concept of the glymphatic system and observations in patients with NTG, we hypothesize that failure of fluid transport via the glymphatic pathway in the optic nerve may be involved in the pathogenesis of some if not many cases of NTG. According to this hypothesis, vascular and CSF factors may share reduced glymphatic transport and perivascular waste clearance in the optic nerve as a final common pathway leading to the development of NTG. In addition, we speculate that some cases of NTG may reflect glymphatic dysfunction in natural brain aging and central nervous system diseases, such as Alzheimer's disease. Clearly, further studies are needed to gain additional insight into the relative contribution of these factors and conditions to reduced glymphatic transport in the optic nerve.
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Affiliation(s)
- Peter Wostyn
- Department of Psychiatry, PC Sint-Amandus, Beernem, Belgium
- Correspondence: Peter Wostyn, Department of Psychiatry, PC Sint-Amandus, Reigerlostraat 10, Beernem, 8730, Belgium, Tel +32-472713719, Fax +32-50-819720, Email
| | - Hanspeter Esriel Killer
- Department of Biomedicine, University of Basel, Basel, Switzerland
- Augenärzte Zentrum Aarau, Aarau, Switzerland
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Xiao M, Hou J, Xu M, Li S, Yang B. Aquaporins in Nervous System. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1398:99-124. [PMID: 36717489 DOI: 10.1007/978-981-19-7415-1_7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Aquaporins (AQPs) mediate water flux between the four distinct water compartments in the central nervous system (CNS). In the present chapter, we mainly focus on the expression and function of the nine AQPs expressed in the CNS, which include five members of aquaporin subfamily: AQP1, AQP4, AQP5, AQP6, and AQP8; three members of aquaglyceroporin subfamily: AQP3, AQP7, and AQP9; and one member of superaquaporin subfamily: AQP11. In addition, AQP1, AQP2, and AQP4 expressed in the peripheral nervous system are also reviewed. AQP4, the predominant water channel in the CNS, is involved both in the astrocyte swelling of cytotoxic edema and the resolution of vasogenic edema and is of pivotal importance in the pathology of brain disorders such as neuromyelitis optica, brain tumors, and neurodegenerative disorders. Moreover, AQP4 has been demonstrated as a functional regulator of recently discovered glymphatic system that is a main contributor to clearance of toxic macromolecule from the brain. Other AQPs are also involved in a variety of important physiological and pathological process in the brain. It has been suggested that AQPs could represent an important target in treatment of brain disorders like cerebral edema. Future investigations are necessary to elucidate the pathological significance of AQPs in the CNS.
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Affiliation(s)
- Ming Xiao
- Jiangsu Province, Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing Medical University, Nanjing, China
| | - Jiaoyu Hou
- Department of Geriatrics, The First Hospital of Jilin University, Changchun, Jilin, China
| | - Mengmeng Xu
- Basic Medical College, Guizhou University of Traditional Chinese Medicine, Guiyang, China
| | - Shao Li
- Department of Physiology, Dalian Medical University, Dalian, China
| | - Baoxue Yang
- School of Basic Medical Sciences, Peking University, Beijing, China.
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Nsiah NY, Inman DM. Destabilizing COXIV in Müller Glia Increases Retinal Glycolysis and Alters Scotopic Electroretinogram. Cells 2022; 11:cells11233756. [PMID: 36497016 PMCID: PMC9737073 DOI: 10.3390/cells11233756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 11/17/2022] [Accepted: 11/22/2022] [Indexed: 11/25/2022] Open
Abstract
Müller glia (MG), the principal glial cell of the retina, have a metabolism that defies categorization into glycolytic versus oxidative. We showed that MG mount a strong hypoxia response to ocular hypertension, raising the question of their relative reliance on mitochondria for function. To explore the role of oxidative phosphorylation (OXPHOS) in MG energy production in vivo, we generated and characterized adult mice in which MG have impaired cytochrome c oxidase (COXIV) activity through knockout of the COXIV constituent COX10. Histochemistry and protein analysis showed that COXIV protein levels were significantly lower in knockout mouse retina compared to control. Loss of COXIV activity in MG did not induce structural abnormalities, though oxidative stress was increased. Electroretinography assessment showed that knocking out COX10 significantly impaired scotopic a- and b-wave responses. Inhibiting mitochondrial respiration in MG also altered the retinal glycolytic profile. However, blocking OXPHOS in MG did not significantly exacerbate retinal ganglion cell (RGC) loss or photopic negative response after ocular hypertension (OHT). These results suggest that MG were able to compensate for reduced COXIV stability by maintaining fundamental processes, but changes in retinal physiology and metabolism-associated proteins indicate subtle changes in MG function.
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Jung SS, Son J, Yi SJ, Kim K, Park HS, Kang HW, Kim HK. Development of Müller cell-based 3D biomimetic model using bioprinting technology. Biomed Mater 2022; 18. [PMID: 36343367 DOI: 10.1088/1748-605x/aca0d5] [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: 08/17/2022] [Accepted: 11/07/2022] [Indexed: 11/09/2022]
Abstract
Müller cells are the principal glial cells for the maintenance of structural stability and metabolic homeostasis in the human retina. Although variousin vitroexperiments using two-dimensional (2D) monolayer cell cultures have been performed, the results provided only limited results because of the lack of 3D structural environment and different cellular morphology. We studied a Müller cell-based 3D biomimetic model for use in experiments on thein vivo-like functions of Müller cells within the sensory retina. Isolated primary Müller cells were bioprinted and a 3D-aligned architecture was induced, which aligned Müller cell structure in retinal tissue. The stereographic and functional characteristics of the biomimetic model were investigated and compared to those of the conventional 2D cultured group. The results showed the potential to generate Müller cell-based biomimetic models with characteristic morphological features such as endfeet, soma, and microvilli. Especially, the 3D Müller cell model under hyperglycemic conditions showed similar responses as observed in thein vivodiabetic model with retinal changes, whereas the conventional 2D cultured group showed different cytokine and growth factor secretions. These results show that our study is a first step toward providing advanced tools to investigate thein vivofunction of Müller cells and to develop complete 3D models of the vertebrate retina.
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Affiliation(s)
- Sung Suk Jung
- Animal and Plant Quarantine Agency, 177 Hyeoksin 8-ro, Gimcheon City, Gyeongsangbuk-do 39660, Republic of Korea
| | - Jeonghyun Son
- Ulsan National Institute of Science and Technology, 50, UNIST-gil, Ulju-gun, Ulsan 44919, Republic of Korea
| | - Soo Jin Yi
- Department of Ophthalmology, School of Medicine, Kyungpook National University, 680 Gukchaebosang-ro, Jung-gu, Daegu 41944, Republic of Korea.,Bio-Medical Institute, Kyungpook National University Hospital, 130 Dongdeok-ro, Jung-gu, Daegu 41944, Republic of Korea.,Department of Biomedical Science, The Graduate School, Kyungpook National University, 680 Gukchaebosang-ro, Jung-gu, Daegu 41944, Republic of Korea
| | - Kyungha Kim
- Ulsan National Institute of Science and Technology, 50, UNIST-gil, Ulju-gun, Ulsan 44919, Republic of Korea
| | - Han Sang Park
- Department of Ophthalmology, School of Medicine, Kyungpook National University, 680 Gukchaebosang-ro, Jung-gu, Daegu 41944, Republic of Korea
| | - Hyun-Wook Kang
- Ulsan National Institute of Science and Technology, 50, UNIST-gil, Ulju-gun, Ulsan 44919, Republic of Korea
| | - Hong Kyun Kim
- Department of Ophthalmology, School of Medicine, Kyungpook National University, 680 Gukchaebosang-ro, Jung-gu, Daegu 41944, Republic of Korea.,Bio-Medical Institute, Kyungpook National University Hospital, 130 Dongdeok-ro, Jung-gu, Daegu 41944, Republic of Korea.,Department of Biomedical Science, The Graduate School, Kyungpook National University, 680 Gukchaebosang-ro, Jung-gu, Daegu 41944, Republic of Korea
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Lai W, Huang J, Fang W, Deng S, Xie Y, Wang W, Qiao T, Xu G, Wang X, Ding F. Optic nerve head: A gatekeeper for vitreous infectious insults? Front Immunol 2022; 13:987771. [PMID: 36203577 PMCID: PMC9531234 DOI: 10.3389/fimmu.2022.987771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 08/31/2022] [Indexed: 11/19/2022] Open
Abstract
The axons of retinal ganglion cells (RGCs) pass through the optic nerve head (ONH) and form the optic nerve (ON). The ONH serves as an anatomical interface between the vitreous cavity and subarachnoid space. After inducing acute neuroinflammation by intravitreal injection of lipopolysaccharides (LPS), we observed inflammatory activation in the retina, but detect no signs of inflammation in the posterior ON or infiltration of inflammatory cells in the ONH. Therefore, we hypothesized that the ONH functions as a barrier to vitreous inflammation. Using transmission electron microscopy, we identified significant increase in G-ratio in the posterior ON on day 7 post intravitreal injection (PII) of LPS compared with the phosphate buffered saline (PBS) group. Moreover, using confocal imaging of ex vivo tissue extracted from Aldh1L1-eGFP reporter mice, we observed that the ONH astrocytes altered their spatial orientation by elongating their morphology along the axonal axis of RGCs in LPS- versus PBS-treated eyes; this was quantified by the ratio of longitudinal (DL) and transverse (DT) diameter of astrocytes and the proportion of longitudinally locating astrocytes. Supportive evidences were further provided by transmission electron microscopic imaging in rat ONH. We further conducted RNA sequencing of ONH on day 1 PII and found LPS induced clear upregulation of immune and inflammatory pathways. Furthermore, gene set enrichment analysis revealed that astrocyte and microglia contributed prominently to the transcriptomic alterations in ONH. Here, we report that the vitreous infectious insults induce morphological changes of ONH astrocytes and transcriptomic alterations in the ONH. Glial responses in the ONH may defend against vitreous infectious insults and serve as a barrier to inflammation for the central nervous system.
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Affiliation(s)
- Wenwen Lai
- Department of Pharmacology, School of Basic Medical Sciences; Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Fudan University, Shanghai, China
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jie Huang
- Department of Pharmacology, School of Basic Medical Sciences; Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Fudan University, Shanghai, China
- Department of Ophthalmology, Eye, Ear, Nose and Throat Hospital; State Key Laboratory of Medical Neurobiology and Ministry of Education Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Wangyi Fang
- Department of Ophthalmology, Shanghai Children’s Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Saiyue Deng
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yi Xie
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Wei Wang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Tong Qiao
- Department of Ophthalmology, Shanghai Children’s Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Gezhi Xu
- Department of Pharmacology, School of Basic Medical Sciences; Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Fudan University, Shanghai, China
- Department of Ophthalmology, Eye, Ear, Nose and Throat Hospital; State Key Laboratory of Medical Neurobiology and Ministry of Education Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Xiaowei Wang
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA, United States
- *Correspondence: Fengfei Ding, ; Xiaowei Wang,
| | - Fengfei Ding
- Department of Pharmacology, School of Basic Medical Sciences; Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Fudan University, Shanghai, China
- Department of Ophthalmology, Eye, Ear, Nose and Throat Hospital; State Key Laboratory of Medical Neurobiology and Ministry of Education Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
- *Correspondence: Fengfei Ding, ; Xiaowei Wang,
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Ocular Lymphatic and Glymphatic Systems: Implications for Retinal Health and Disease. Int J Mol Sci 2022; 23:ijms231710139. [PMID: 36077535 PMCID: PMC9456449 DOI: 10.3390/ijms231710139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 09/01/2022] [Accepted: 09/02/2022] [Indexed: 11/17/2022] Open
Abstract
Clearance of ocular fluid and metabolic waste is a critical function of the eye in health and disease. The eye has distinct fluid outflow pathways in both the anterior and posterior segments. Although the anterior outflow pathway is well characterized, little is known about posterior outflow routes. Recent studies suggest that lymphatic and glymphatic systems play an important role in the clearance of fluid and waste products from the posterior segment of the eye. The lymphatic system is a vascular network that runs parallel to the blood circulatory system. It plays an essential role in maintenance of fluid homeostasis and immune surveillance in the body. Recent studies have reported lymphatics in the cornea (under pathological conditions), ciliary body, choroid, and optic nerve meninges. The evidence of lymphatics in optic nerve meninges is, however, limited. An alternative lymphatic system termed the glymphatic system was recently discovered in the rodent eye and brain. This system is a glial cell-based perivascular network responsible for the clearance of interstitial fluid and metabolic waste. In this review, we will discuss our current knowledge of ocular lymphatic and glymphatic systems and their role in retinal degenerative diseases.
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Gorina YV, Salmina AB, Erofeev AI, Gerasimov EI, Bolshakova AV, Balaban PM, Bezprozvanny IB, Vlasova OL. Astrocyte Activation Markers. BIOCHEMISTRY. BIOKHIMIIA 2022; 87:851-870. [PMID: 36180985 DOI: 10.1134/s0006297922090012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 06/27/2022] [Accepted: 06/28/2022] [Indexed: 06/16/2023]
Abstract
Astrocytes are the most common type of glial cells that provide homeostasis and protection of the central nervous system. Important specific characteristic of astrocytes is manifestation of morphological heterogeneity, which is directly dependent on localization in a particular area of the brain. Astrocytes can integrate into neural networks and keep neurons active in various areas of the brain. Moreover, astrocytes express a variety of receptors, channels, and membrane transporters, which underlie their peculiar metabolic activity, and, hence, determine plasticity of the central nervous system during development and aging. Such complex structural and functional organization of astrocytes requires the use of modern methods for their identification and analysis. Considering the important fact that determining the most appropriate marker for polymorphic and multiple subgroups of astrocytes is of decisive importance for studying their multifunctionality, this review presents markers, modern imaging techniques, and identification of astrocytes, which comprise a valuable resource for studying structural and functional properties of astrocytes, as well as facilitate better understanding of the extent to which astrocytes contribute to neuronal activity.
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Affiliation(s)
- Yana V Gorina
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, 194091, Russia.
- Research Institute of Molecular Medicine and Pathobiochemistry, Voino-Yasenetsky Krasnoyarsk State Medical University, Krasnoyarsk, 660022, Russia
| | - Alla B Salmina
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, 194091, Russia
- Research Institute of Molecular Medicine and Pathobiochemistry, Voino-Yasenetsky Krasnoyarsk State Medical University, Krasnoyarsk, 660022, Russia
- Laboratory of Neurobiology and Tissue Engineering, Brain Institute, Research Center of Neurology, Moscow, 105064, Russia
| | - Alexander I Erofeev
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, 194091, Russia
| | - Evgeniy I Gerasimov
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, 194091, Russia
| | - Anastasia V Bolshakova
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, 194091, Russia
| | - Pavel M Balaban
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, 194091, Russia
- Laboratory of Cellular Neurobiology of Learning, Institute of Higher Nervous Activity, Moscow, 117485, Russia
| | - Ilya B Bezprozvanny
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, 194091, Russia
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Olga L Vlasova
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, 194091, Russia
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Abstract
We review theoretical and numerical models of the glymphatic system, which circulates cerebrospinal fluid and interstitial fluid around the brain, facilitating solute transport. Models enable hypothesis development and predictions of transport, with clinical applications including drug delivery, stroke, cardiac arrest, and neurodegenerative disorders like Alzheimer’s disease. We sort existing models into broad categories by anatomical function: Perivascular flow, transport in brain parenchyma, interfaces to perivascular spaces, efflux routes, and links to neuronal activity. Needs and opportunities for future work are highlighted wherever possible; new models, expanded models, and novel experiments to inform models could all have tremendous value for advancing the field.
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Ochoa-de la Paz LD, Gulias-Cañizo R. Glia as a key factor in cell volume regulation processes of the central nervous system. Front Cell Neurosci 2022; 16:967496. [PMID: 36090789 PMCID: PMC9453262 DOI: 10.3389/fncel.2022.967496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 08/03/2022] [Indexed: 11/23/2022] Open
Abstract
Brain edema is a pathological condition with potentially fatal consequences, related to cerebral injuries such as ischemia, chronic renal failure, uremia, and diabetes, among others. Under these pathological states, the cell volume control processes are fully compromised, because brain cells are unable to regulate the movement of water, mainly regulated by osmotic gradients. The processes involved in cell volume regulation are homeostatic mechanisms that depend on the mobilization of osmolytes (ions, organic molecules, and polyols) in the necessary direction to counteract changes in osmolyte concentration in response to water movement. The expression and coordinated function of proteins related to the cell volume regulation process, such as water channels, ion channels, and other cotransport systems in the glial cells, and considering the glial cell proportion compared to neuronal cells, leads to consider the astroglial network the main regulatory unit for water homeostasis in the central nervous system (CNS). In the last decade, several studies highlighted the pivotal role of glia in the cell volume regulation process and water homeostasis in the brain, including the retina; any malfunction of this astroglial network generates a lack of the ability to regulate the osmotic changes and water movements and consequently exacerbates the pathological condition.
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Affiliation(s)
- Lenin David Ochoa-de la Paz
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico
- Asociación para Evitar la Ceguera en México (APEC), Unidad de Investigación APEC-UNAM, Mexico
- *Correspondence: Lenin David Ochoa-de la Paz
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Lee JH, Moon Y, Kwon YN, Shin JH, Kim SM, Jung JH. Changes of retinal structure and visual function in patients with demyelinating transverse myelitis. Neurol Sci 2022; 43:6425-6431. [DOI: 10.1007/s10072-022-06315-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 08/02/2022] [Indexed: 11/27/2022]
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Non-vasogenic cystoid maculopathies. Prog Retin Eye Res 2022; 91:101092. [PMID: 35927124 DOI: 10.1016/j.preteyeres.2022.101092] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 05/30/2022] [Accepted: 06/01/2022] [Indexed: 11/23/2022]
Abstract
Besides cystoid macular edema due to a blood-retinal barrier breakdown, another type of macular cystoid spaces referred to as non-vasogenic cystoid maculopathies (NVCM) may be detected on optical coherence tomography but not on fluorescein angiography. Various causes may disrupt retinal cell cohesion or impair retinal pigment epithelium (RPE) and Müller cell functions in the maintenance of retinal dehydration, resulting in cystoid spaces formation. Tractional causes include vitreomacular traction, epiretinal membranes and myopic foveoschisis. Surgical treatment does not always allow cystoid space resorption. In inherited retinal dystrophies, cystoid spaces may be part of the disease as in X-linked retinoschisis or enhanced S-cone syndrome, or occur occasionally as in bestrophinopathies, retinitis pigmentosa and allied diseases, congenital microphthalmia, choroideremia, gyrate atrophy and Bietti crystalline dystrophy. In macular telangiectasia type 2, cystoid spaces and cavitations do not depend on the fluid leakage from telangiectasia. Various causes affecting RPE function may result in NVCM such as chronic central serous chorioretinopathy and paraneoplastic syndromes. Non-exudative age macular degeneration may also be complicated by intraretinal cystoid spaces in the absence of fluorescein leakage. In these diseases, cystoid spaces occur in a context of retinal cell loss. Various causes of optic atrophy, including open-angle glaucoma, result in microcystoid spaces in the inner nuclear layer due to a retrograde transsynaptic degeneration. Lastly, drug toxicity may also induce cystoid maculopathy. Identifying NVCM on multimodal imaging, including fluorescein angiography if needed, allows guiding the diagnosis of the causative disease and choosing adequate treatment when available.
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Neuromyelitis Optica Spectrum Disorder: From Basic Research to Clinical Perspectives. Int J Mol Sci 2022; 23:ijms23147908. [PMID: 35887254 PMCID: PMC9323454 DOI: 10.3390/ijms23147908] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 07/08/2022] [Accepted: 07/15/2022] [Indexed: 02/05/2023] Open
Abstract
Neuromyelitis optica spectrum disorder (NMOSD) is an inflammatory disease of the central nervous system characterized by relapses and autoimmunity caused by antibodies against the astrocyte water channel protein aquaporin-4. Over the past decade, there have been significant advances in the biologic knowledge of NMOSD, which resulted in the IDENTIFICATION of variable disease phenotypes, biomarkers, and complex inflammatory cascades involved in disease pathogenesis. Ongoing clinical trials are looking at new treatments targeting NMOSD relapses. This review aims to provide an update on recent studies regarding issues related to NMOSD, including the pathophysiology of the disease, the potential use of serum and cerebrospinal fluid cytokines as disease biomarkers, the clinical utilization of ocular coherence tomography, and the comparison of different animal models of NMOSD.
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Kimball EC, Quillen S, Pease ME, Keuthan C, Nagalingam A, Zack DJ, Johnson TV, Quigley HA. Aquaporin 4 is not present in normal porcine and human lamina cribrosa. PLoS One 2022; 17:e0268541. [PMID: 35709078 PMCID: PMC9202842 DOI: 10.1371/journal.pone.0268541] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 05/03/2022] [Indexed: 02/02/2023] Open
Abstract
Aquaporin 4 is absent from astrocytes in the rodent optic nerve head, despite high expression in the retina and myelinated optic nerve. The purpose of this study was to quantify regional aquaporin channel expression in astrocytes of the porcine and human mouse optic nerve (ON). Ocular tissue sections were immunolabeled for aquaporins 1(AQP1), 4(AQP4), and 9(AQP9), myelin basic protein (MBP), glial fibrillary acidic protein (GFAP) and alpha-dystroglycan (αDG) for their presence in retina, lamina, myelin transition zone (MTZ, region just posterior to lamina) and myelinated ON (MON). Semi- quantification of AQP4 labeling & real-time quantitative PCR (qPCR) data were analyzed in retina and ON tissue. Porcine and control human eyes had abundant AQP4 in Müller cells, retinal astrocytes, and myelinated ON (MON), but minimal expression in the lamina cribrosa. AQP1 and AQP9 were present in retina, but not in the lamina. Immunolabeling of GFAP and αDG was similar in lamina, myelin transition zone (MTZ) and MON regions. Semi-quantitative AQP4 labeling was at background level in lamina, increasing in the MTZ, and highest in the MON (lamina vs MTZ, MON; p≤0.05, p≤0.01, respectively). Expression of AQP4 mRNA was minimal in lamina and substantial in MTZ and MON, while GFAP mRNA expression was uniform among the lamina, MTZ, and MON regions. Western blot assay showed AQP4 protein expression in the MON samples, but none was detected in the lamina tissue. The minimal presence of AQP4 in the lamina is a specific regional phenotype of astrocytes in the mammalian optic nerve head.
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Affiliation(s)
- Elizabeth C. Kimball
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Sarah Quillen
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Mary E. Pease
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Casey Keuthan
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Aru Nagalingam
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Donald J. Zack
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Thomas V. Johnson
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Harry A. Quigley
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
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Chiang PP, Kuo SP, Newman EA. Cellular mechanisms mediating activity-dependent extracellular space shrinkage in the retina. Glia 2022; 70:1927-1937. [PMID: 35678626 PMCID: PMC9378592 DOI: 10.1002/glia.24228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 05/25/2022] [Accepted: 05/26/2022] [Indexed: 11/30/2022]
Abstract
Volume transmission plays an essential role in CNS function, with neurotransmitters released from synapses diffusing through the extracellular space (ECS) to distant sites. Changes in the ECS volume fraction (α) will influence the diffusion and the concentration of transmitters within the ECS. We have recently shown that neuronal activity evoked by physiological photic stimuli results in rapid decreases in ECS α as large as 10% in the retina. We now characterize the cellular mechanisms responsible for this ECS shrinkage. We find that block of inwardly rectifying K+ channels with Ba2+, inhibition of the Na+/K+/2Cl− cotransporter with bumetanide, or block of AQP4 water channels with TGN‐020 do not diminish the light‐evoked ECS decrease. Inhibition of the Na+/HCO3− cotransporter by removing HCO3− from the superfusate, in contrast, reduces the light‐evoked ECS decrease by 95.6%. Inhibition of the monocarboxylate transporter with alpha‐cyano‐4‐hydroxycinnamate (4‐CIN) also reduces the ECS shrinkage, but only by 32.5%. We tested whether the swelling of Müller cells, the principal glial cells of the retina, is responsible for the light‐evoked ECS shrinkage. Light stimulation evoked a 6.3% increase in the volume of the fine processes of Müller cells. This volume increase was reduced by 97.1% when HCO3− was removed from the superfusate. We conclude that a large fraction of the activity‐dependent decrease in ECS α is generated by the activation of the Na+/HCO3− cotransporter in Müller cells. The monocarboxylate transporter may also contribute to the response.
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Affiliation(s)
- Pei-Pei Chiang
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota, USA
| | - Sidney P Kuo
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota, USA
| | - Eric A Newman
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota, USA
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Abe Y, Yasui M. Aquaporin-4 in Neuromyelitis Optica Spectrum Disorders: A Target of Autoimmunity in the Central Nervous System. Biomolecules 2022; 12:biom12040591. [PMID: 35454180 PMCID: PMC9030581 DOI: 10.3390/biom12040591] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 04/11/2022] [Accepted: 04/12/2022] [Indexed: 12/20/2022] Open
Abstract
Since the discovery of a specific autoantibody in patients with neuromyelitis optica spectrum disorder (NMOSD) in 2004, the water channel aquaporin-4 (AQP4) has attracted attention as a target of autoimmune diseases of the central nervous system. In NMOSD, the autoantibody (NMO-IgG) binds to the extracellular loops of AQP4 as expressed in perivascular astrocytic end-feet and disrupts astrocytes in a complement-dependent manner. NMO-IgG is an excellent marker for distinguishing the disease from other inflammatory demyelinating diseases, such as multiple sclerosis. The unique higher-order structure of AQP4—called orthogonal arrays of particles (OAPs)—as well as its subcellular localization may play a crucial role in the pathogenesis of the disease. Recent studies have also demonstrated complement-independent cytotoxic effects of NMO-IgG. Antibody-induced endocytosis of AQP4 has been suggested to be involved in this mechanism. This review focuses on the binding properties of antibodies that recognize the extracellular region of AQP4 and the characteristics of AQP4 that are implicated in the pathogenesis of NMOSD.
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Affiliation(s)
- Yoichiro Abe
- Department of Pharmacology, Keio University School of Medicine, Tokyo 160-8582, Japan
- Keio University Global Research Institute, Tokyo 108-8345, Japan
- Correspondence: (Y.A.); (M.Y.); Tel.: +81-3-5363-3751 (M.Y.)
| | - Masato Yasui
- Department of Pharmacology, Keio University School of Medicine, Tokyo 160-8582, Japan
- Keio University Global Research Institute, Tokyo 108-8345, Japan
- Correspondence: (Y.A.); (M.Y.); Tel.: +81-3-5363-3751 (M.Y.)
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37
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Cellular Distribution of Brain Aquaporins and Their Contribution to Cerebrospinal Fluid Homeostasis and Hydrocephalus. Biomolecules 2022; 12:biom12040530. [PMID: 35454119 PMCID: PMC9025855 DOI: 10.3390/biom12040530] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 03/28/2022] [Accepted: 03/30/2022] [Indexed: 01/19/2023] Open
Abstract
Brain aquaporins facilitate the movement of water between the four water compartments: blood, cerebrospinal fluid, interstitial fluid, and intracellular fluid. This work analyzes the expression of the four most abundant aquaporins (AQPs) (AQP1, AQP4, AQP9, and AQP11) in the brains of mice and discuss their contribution to hydrocephalus. We analyzed available data from single-cell RNA sequencing of the central nervous system of mice to describe the expression of aquaporins and compare their distribution with that based on qPCR, western blot, and immunohistochemistry assays. Expression of AQP1 in the apical cell membrane of choroid plexus epithelial cells and of AQP4 in ependymal cells, glia limitans, and astrocyte processes in the pericapillary end foot is consistent with the involvement of both proteins in cerebrospinal fluid homeostasis. The expression of both aquaporins compensates for experimentally induced hydrocephalus in the animals. Recent data demonstrate that hypoxia in aged animals alters AQP4 expression in the choroidal plexus and cortex, increasing the ventricle size and intraventricular pressure. Cerebral distensibility is reduced in parallel with a reduction in cerebrospinal fluid drainage and cognitive deterioration. We propose that aged mice chronically exposed to hypoxia represent an excellent experimental model for studying the pathophysiological characteristics of idiopathic normal pressure hydrocephalus and roles for AQPs in such disease.
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Understanding Neurodegeneration from a Clinical and Therapeutic Perspective in Early Diabetic Retinopathy. Nutrients 2022; 14:nu14040792. [PMID: 35215442 PMCID: PMC8877033 DOI: 10.3390/nu14040792] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 02/10/2022] [Accepted: 02/11/2022] [Indexed: 02/05/2023] Open
Abstract
Recent evidence indicates that neurodegeneration is a critical element of diabetic retinopathy (DR) pathogenesis. The neuronal cells’ apoptosis contributes to microvascular impairment and blood–retinal barrier breakdown. Therefore, neurodegeneration represents an early intervention target to slow and prevent the development of microvascular alterations visible on clinical examination. Multimodal imaging features and functional assessment can permit the identification of neuronal damage in a subclinical stage before the recognition of DR signs. Clinical features of neurodegeneration are crucial in identifying patients at high risk of developing a vascular impairment and, thus, serve as outcome measures to understand the efficacy of supplementation. The optimal approach for targeting neurodegeneration contemplates the use of topical compounds that possibly act on different elements of the pathogenic cascade. To date, clinical trials available on humans tested three different topical agents, including brimonidine, somatostatin, and citicoline, with promising results.
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Wagner K, Unger L, Salman MM, Kitchen P, Bill RM, Yool AJ. Signaling Mechanisms and Pharmacological Modulators Governing Diverse Aquaporin Functions in Human Health and Disease. Int J Mol Sci 2022; 23:ijms23031388. [PMID: 35163313 PMCID: PMC8836214 DOI: 10.3390/ijms23031388] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 01/18/2022] [Accepted: 01/20/2022] [Indexed: 02/07/2023] Open
Abstract
The aquaporins (AQPs) are a family of small integral membrane proteins that facilitate the bidirectional transport of water across biological membranes in response to osmotic pressure gradients as well as enable the transmembrane diffusion of small neutral solutes (such as urea, glycerol, and hydrogen peroxide) and ions. AQPs are expressed throughout the human body. Here, we review their key roles in fluid homeostasis, glandular secretions, signal transduction and sensation, barrier function, immunity and inflammation, cell migration, and angiogenesis. Evidence from a wide variety of studies now supports a view of the functions of AQPs being much more complex than simply mediating the passive flow of water across biological membranes. The discovery and development of small-molecule AQP inhibitors for research use and therapeutic development will lead to new insights into the basic biology of and novel treatments for the wide range of AQP-associated disorders.
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Affiliation(s)
- Kim Wagner
- School of Biomedicine, University of Adelaide, Adelaide, SA 5005, Australia;
| | - Lucas Unger
- College of Health and Life Sciences, Aston University, Birmingham B4 7ET, UK; (L.U.); (P.K.)
| | - Mootaz M. Salman
- Department of Physiology Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, UK;
- Oxford Parkinson’s Disease Centre, University of Oxford, South Parks Road, Oxford OX1 3QX, UK
| | - Philip Kitchen
- College of Health and Life Sciences, Aston University, Birmingham B4 7ET, UK; (L.U.); (P.K.)
| | - Roslyn M. Bill
- College of Health and Life Sciences, Aston University, Birmingham B4 7ET, UK; (L.U.); (P.K.)
- Correspondence: (R.M.B.); (A.J.Y.); Tel.: +44-121-204-4274 (R.M.B.); +61-8-8313-3359 (A.J.Y.)
| | - Andrea J. Yool
- School of Biomedicine, University of Adelaide, Adelaide, SA 5005, Australia;
- Correspondence: (R.M.B.); (A.J.Y.); Tel.: +44-121-204-4274 (R.M.B.); +61-8-8313-3359 (A.J.Y.)
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Szczygielski J, Kopańska M, Wysocka A, Oertel J. Cerebral Microcirculation, Perivascular Unit, and Glymphatic System: Role of Aquaporin-4 as the Gatekeeper for Water Homeostasis. Front Neurol 2021; 12:767470. [PMID: 34966347 PMCID: PMC8710539 DOI: 10.3389/fneur.2021.767470] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 11/12/2021] [Indexed: 12/13/2022] Open
Abstract
In the past, water homeostasis of the brain was understood as a certain quantitative equilibrium of water content between intravascular, interstitial, and intracellular spaces governed mostly by hydrostatic effects i.e., strictly by physical laws. The recent achievements in molecular bioscience have led to substantial changes in this regard. Some new concepts elaborate the idea that all compartments involved in cerebral fluid homeostasis create a functional continuum with an active and precise regulation of fluid exchange between them rather than only serving as separate fluid receptacles with mere passive diffusion mechanisms, based on hydrostatic pressure. According to these concepts, aquaporin-4 (AQP4) plays the central role in cerebral fluid homeostasis, acting as a water channel protein. The AQP4 not only enables water permeability through the blood-brain barrier but also regulates water exchange between perivascular spaces and the rest of the glymphatic system, described as pan-cerebral fluid pathway interlacing macroscopic cerebrospinal fluid (CSF) spaces with the interstitial fluid of brain tissue. With regards to this, AQP4 makes water shift strongly dependent on active processes including changes in cerebral microcirculation and autoregulation of brain vessels capacity. In this paper, the role of the AQP4 as the gatekeeper, regulating the water exchange between intracellular space, glymphatic system (including the so-called neurovascular units), and intravascular compartment is reviewed. In addition, the new concepts of brain edema as a misbalance in water homeostasis are critically appraised based on the newly described role of AQP4 for fluid permeation. Finally, the relevance of these hypotheses for clinical conditions (including brain trauma and stroke) and for both new and old therapy concepts are analyzed.
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Affiliation(s)
- Jacek Szczygielski
- Department of Neurosurgery, Institute of Medical Sciences, University of Rzeszów, Rzeszów, Poland.,Department of Neurosurgery, Faculty of Medicine and Saarland University Medical Center, Saarland University, Homburg, Germany
| | - Marta Kopańska
- Department of Pathophysiology, Institute of Medical Sciences, University of Rzeszów, Rzeszów, Poland
| | - Anna Wysocka
- Chair of Internal Medicine and Department of Internal Medicine in Nursing, Faculty of Health Sciences, Medical University of Lublin, Lublin, Poland
| | - Joachim Oertel
- Department of Neurosurgery, Faculty of Medicine and Saarland University Medical Center, Saarland University, Homburg, Germany
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Abstract
Optic nerve health is essential for proper function of the visual system. However, the pathophysiology of certain neurodegenerative disease processes affecting the optic nerve, such as glaucoma, is not fully understood. Recently, it was hypothesized that a lack of proper clearance of neurotoxins contributes to neurodegenerative diseases. The ability to clear metabolic waste is essential for tissue homeostasis in mammals, including humans. While the brain lacks the traditional lymphatic drainage system identified in other anatomical regions, there is growing evidence of a glymphatic system in the central nervous system, which structurally includes the optic nerve. Named to acknowledge the supportive role of astroglial cells, this perivascular fluid drainage system is essential to remove toxic metabolites from the central nervous system. Herein, we review existing literature describing the physiology and dysfunction of the glymphatic system specifically as it relates to the optic nerve. We summarize key imaging studies demonstrating the existence of a glymphatic system in the optic nerves of wild-type rodents, aquaporin 4-null rodents, and humans; glymphatic imaging studies in diseases where the optic nerve is impaired; and current evidence regarding pharmacological and lifestyle interventions that may help promote glymphatic function to improve optic nerve health. We conclude by highlighting future research directions that could be applied to improve imaging detection and guide therapeutic interventions for diseases affecting the optic nerve.
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Affiliation(s)
- Anisha Kasi
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, USA
| | - Crystal Liu
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, USA
| | - Muneeb A Faiq
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, USA
| | - Kevin C Chan
- Department of Ophthalmology; Department of Radiology; Neuroscience Institute, NYU Grossman School of Medicine, NYU Langone Health; Center for Neural Science, College of Arts and Science, New York University, New York, NY, USA
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Guzel S, Cai CL, Aranda JV, Beharry KD. Dose Response of Bumetanide on Aquaporins and Angiogenesis Biomarkers in Human Retinal Endothelial Cells Exposed to Intermittent Hypoxia. Pharmaceuticals (Basel) 2021; 14:ph14100967. [PMID: 34681190 PMCID: PMC8538009 DOI: 10.3390/ph14100967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 09/14/2021] [Accepted: 09/16/2021] [Indexed: 11/16/2022] Open
Abstract
Aquaporins (AQPs) are important for regulating cellular water, solute transport, and balance. Recently, AQPs have also been recognized as playing a key role in cell migration and angiogenesis. In the retina, hypoxia induces vascular endothelial growth factor (VEGF), a potent angiogenic and vascular permeability factor, resulting in retinal edema, which is facilitated by AQPs. Bumetanide is a diuretic agent and AQP 1–4 blocker. We tested the hypothesis that bumetanide suppression of AQPs ameliorates intermittent hypoxia (IH)-induced angiogenesis and oxidative stress in human microvascular retinal endothelial cells (HMRECs). HMRECs were treated with a low-dose (0.05 µg/mL) or high-dose (0.2 µg/mL) of bumetanide and were exposed to normoxia (Nx), hyperoxia (50% O2), or IH (50% O2 with brief hypoxia 5% O2) for 24, 48, and 72 h. Angiogenesis and oxidative stress biomarkers were determined in the culture media, and the cells were assessed for tube formation capacity and AQP-1 and -4 expression. Both doses of bumetanide significantly decreased oxidative stress and angiogenesis biomarkers. This response was reflected by reductions in tube formation capacity and AQP expression. These findings confirm the role of AQPs in retinal angiogenesis. Therapeutic targeting of AQPs with bumetanide may be advantageous for IH-induced aberrant retinal development.
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Affiliation(s)
- Sibel Guzel
- Department of Pediatrics, Division of Neonatal-Perinatal Medicine, State University of New York, Downstate Medical Center, Brooklyn, NY 11203, USA; (S.G.); (C.L.C.); (J.V.A.)
| | - Charles L. Cai
- Department of Pediatrics, Division of Neonatal-Perinatal Medicine, State University of New York, Downstate Medical Center, Brooklyn, NY 11203, USA; (S.G.); (C.L.C.); (J.V.A.)
| | - Jacob V. Aranda
- Department of Pediatrics, Division of Neonatal-Perinatal Medicine, State University of New York, Downstate Medical Center, Brooklyn, NY 11203, USA; (S.G.); (C.L.C.); (J.V.A.)
- Department of Ophthalmology, State University of New York, Downstate Medical Center, Brooklyn, NY 11203, USA
- State University of New York Eye Institute, Brooklyn, NY 11203, USA
| | - Kay D. Beharry
- Department of Pediatrics, Division of Neonatal-Perinatal Medicine, State University of New York, Downstate Medical Center, Brooklyn, NY 11203, USA; (S.G.); (C.L.C.); (J.V.A.)
- Department of Ophthalmology, State University of New York, Downstate Medical Center, Brooklyn, NY 11203, USA
- State University of New York Eye Institute, Brooklyn, NY 11203, USA
- Correspondence: ; Tel.: +1-(718)-270-1475
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Martinac AD, Fletcher DF, Bilston LE. Phase offset between arterial pulsations and subarachnoid space pressure fluctuations are unlikely to drive periarterial cerebrospinal fluid flow. Biomech Model Mechanobiol 2021; 20:1751-1766. [PMID: 34275063 DOI: 10.1007/s10237-021-01474-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 06/02/2021] [Indexed: 11/24/2022]
Abstract
Circulation of fluid through the central nervous system maintains fluid homeostasis and is involved in solute clearance. The glymphatic system is hypothesised to facilitate waste clearance in the brain, with inflow via periarterial spaces, bulk flow through the parenchyma, and outflow via perivenous spaces. The driving force for this mechanism is unknown. Previous modelling in the spinal cord suggests that timing offsets between arterial and subarachnoid space pressure pulses can enable net inflow in perivascular spaces (PVS). This study adapted the spinal pulse offset mechanism to the brain and simulated movement of tracer particles used in experiments. Both bulk flow and diffusive movement of tracer were simulated. Intracranial pressure pulses were applied to one end of a 300-μm-long perivascular space combined with a moving arterial wall simulating arterial pulsations. The simulations indicate the pulse offset mechanism can enable net inflow via PVS; however, it is unknown whether the temporal offset required is physiologically realistic. Increasing the positive component of the ICP (intracranial pressure) pulse increased net flow. Tracer particles driven by bulk flow reached the outlet of the PVS with a net speed of ~ 16 μm/s when the permeability was two orders of magnitude higher than values in the literature. These particles were unable to penetrate into the parenchyma in the absence of diffusion. Dispersion dominated tracer movement in the parenchyma. Further research is required to reconcile discrepancies between these results, and both experimental and computational studies.
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Affiliation(s)
- Adam D Martinac
- Neuroscience Research Australia and Prince of Wales Clinical School, UNSW, Kensington, Australia.
| | - David F Fletcher
- School of Chemical and Biomolecular Engineering, The University of Sydney, Camperdown, Australia
| | - Lynne E Bilston
- Neuroscience Research Australia and Prince of Wales Clinical School, UNSW, Kensington, Australia
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44
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Heuser K, Enger R. Astrocytic Ca 2+ Signaling in Epilepsy. Front Cell Neurosci 2021; 15:695380. [PMID: 34335188 PMCID: PMC8320018 DOI: 10.3389/fncel.2021.695380] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 06/16/2021] [Indexed: 01/10/2023] Open
Abstract
Epilepsy is one of the most common neurological disorders – estimated to affect at least 65 million worldwide. Most of the epilepsy research has so far focused on how to dampen neuronal discharges and to explain how changes in intrinsic neuronal activity or network function cause seizures. As a result, pharmacological therapy has largely been limited to symptomatic treatment targeted at neurons. Given the expanding spectrum of functions ascribed to the non-neuronal constituents of the brain, in both physiological brain function and in brain disorders, it is natural to closely consider the roles of astrocytes in epilepsy. It is now widely accepted that astrocytes are key controllers of the composition of the extracellular fluids, and may directly interact with neurons by releasing gliotransmitters. A central tenet is that astrocytic intracellular Ca2+ signals promote release of such signaling substances, either through synaptic or non-synaptic mechanisms. Accruing evidence suggests that astrocytic Ca2+ signals play important roles in both seizures and epilepsy, and this review aims to highlight the current knowledge of the roles of this central astrocytic signaling mechanism in ictogenesis and epileptogenesis.
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Affiliation(s)
- Kjell Heuser
- Department of Neurology, Oslo University Hospital, Rikshospitalet, Oslo, Norway
| | - Rune Enger
- Letten Centre and GliaLab, Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
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Wang X, Lou N, Eberhardt A, Yang Y, Kusk P, Xu Q, Förstera B, Peng S, Shi M, Ladrón-de-Guevara A, Delle C, Sigurdsson B, Xavier ALR, Ertürk A, Libby RT, Chen L, Thrane AS, Nedergaard M. An ocular glymphatic clearance system removes β-amyloid from the rodent eye. Sci Transl Med 2021; 12:12/536/eaaw3210. [PMID: 32213628 DOI: 10.1126/scitranslmed.aaw3210] [Citation(s) in RCA: 114] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 08/24/2019] [Accepted: 12/30/2019] [Indexed: 12/31/2022]
Abstract
Despite high metabolic activity, the retina and optic nerve head lack traditional lymphatic drainage. We here identified an ocular glymphatic clearance route for fluid and wastes via the proximal optic nerve in rodents. β-amyloid (Aβ) was cleared from the retina and vitreous via a pathway dependent on glial water channel aquaporin-4 (AQP4) and driven by the ocular-cranial pressure difference. After traversing the lamina barrier, intra-axonal Aβ was cleared via the perivenous space and subsequently drained to lymphatic vessels. Light-induced pupil constriction enhanced efflux, whereas atropine or raising intracranial pressure blocked efflux. In two distinct murine models of glaucoma, Aβ leaked from the eye via defects in the lamina barrier instead of directional axonal efflux. The results suggest that, in rodents, the removal of fluid and metabolites from the intraocular space occurs through a glymphatic pathway that might be impaired in glaucoma.
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Affiliation(s)
- Xiaowei Wang
- Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark.,Center for Translational Neuromedicine, University of Rochester Medical School, Elmwood Avenue 601, Rochester, NY 14642, USA
| | - Nanhong Lou
- Center for Translational Neuromedicine, University of Rochester Medical School, Elmwood Avenue 601, Rochester, NY 14642, USA
| | - Allison Eberhardt
- Center for Translational Neuromedicine, University of Rochester Medical School, Elmwood Avenue 601, Rochester, NY 14642, USA
| | - Yujia Yang
- Center for Eye Disease and Development, Vision Science Graduate Program, and School of Optometry, University of California Berkeley, Berkeley, CA 94720, USA
| | - Peter Kusk
- Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark
| | - Qiwu Xu
- Center for Translational Neuromedicine, University of Rochester Medical School, Elmwood Avenue 601, Rochester, NY 14642, USA
| | - Benjamin Förstera
- Institute for Stroke and Dementia Research, Klinikum der Universität München, Ludwig Maximilians University of Munich (LMU), 81377 Munich, Germany.,Institute for Tissue Engineering and Regenerative Medicine (iTERM), Helmholtz Center München, 85764 Munich, Germany
| | - Sisi Peng
- Center for Translational Neuromedicine, University of Rochester Medical School, Elmwood Avenue 601, Rochester, NY 14642, USA
| | - Meng Shi
- Center for Eye Disease and Development, Vision Science Graduate Program, and School of Optometry, University of California Berkeley, Berkeley, CA 94720, USA
| | - Antonio Ladrón-de-Guevara
- Center for Translational Neuromedicine, University of Rochester Medical School, Elmwood Avenue 601, Rochester, NY 14642, USA
| | - Christine Delle
- Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark
| | - Björn Sigurdsson
- Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark
| | - Anna L R Xavier
- Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark
| | - Ali Ertürk
- Institute for Stroke and Dementia Research, Klinikum der Universität München, Ludwig Maximilians University of Munich (LMU), 81377 Munich, Germany.,Institute for Tissue Engineering and Regenerative Medicine (iTERM), Helmholtz Center München, 85764 Munich, Germany
| | - Richard T Libby
- Department of Ophthalmology, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Lu Chen
- Center for Eye Disease and Development, Vision Science Graduate Program, and School of Optometry, University of California Berkeley, Berkeley, CA 94720, USA.
| | - Alexander S Thrane
- Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark.,Department of Ophthalmology, Haukeland University Hospital, Jonas Lies Vei 65, 5021 Bergen, Norway
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark. .,Center for Translational Neuromedicine, University of Rochester Medical School, Elmwood Avenue 601, Rochester, NY 14642, USA
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Mesentier-Louro LA, Rangel B, Stell L, Shariati MA, Dalal R, Nathan A, Yuan K, de Jesus Perez V, Liao YJ. Hypoxia-induced inflammation: Profiling the first 24-hour posthypoxic plasma and central nervous system changes. PLoS One 2021; 16:e0246681. [PMID: 33661927 PMCID: PMC7932147 DOI: 10.1371/journal.pone.0246681] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 01/22/2021] [Indexed: 11/18/2022] Open
Abstract
Central nervous system and visual dysfunction is an unfortunate consequence of systemic hypoxia in the setting of cardiopulmonary disease, including infection with SARS-CoV-2, high-altitude cerebral edema and retinopathy and other conditions. Hypoxia-induced inflammatory signaling may lead to retinal inflammation, gliosis and visual disturbances. We investigated the consequences of systemic hypoxia using serial retinal optical coherence tomography and by assessing the earliest changes within 24h after hypoxia by measuring a proteomics panel of 39 cytokines, chemokines and growth factors in the plasma and retina, as well as using retinal histology. We induced severe systemic hypoxia in adult C57BL/6 mice using a hypoxia chamber (10% O2) for 1 week and rapidly assessed measurements within 1h compared with 18h after hypoxia. Optical coherence tomography revealed retinal tissue edema at 18h after hypoxia. Hierarchical clustering of plasma and retinal immune molecules revealed obvious segregation of the 1h posthypoxia group away from that of controls. One hour after hypoxia, there were 10 significantly increased molecules in plasma and 4 in retina. Interleukin-1β and vascular endothelial growth factor were increased in both tissues. Concomitantly, there was significantly increased aquaporin-4, decreased Kir4.1, and increased gliosis in retinal histology. In summary, the immediate posthypoxic period is characterized by molecular changes consistent with systemic and retinal inflammation and retinal glial changes important in water transport, leading to tissue edema. This posthypoxic inflammation rapidly improves within 24h, consistent with the typically mild and transient visual disturbance in hypoxia, such as in high-altitude retinopathy. Given hypoxia increases risk of vision loss, more studies in at-risk patients, such as plasma immune profiling and in vivo retinal imaging, are needed in order to identify novel diagnostic or prognostic biomarkers of visual impairment in systemic hypoxia.
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Affiliation(s)
- Louise A. Mesentier-Louro
- Department of Ophthalmology, Stanford University, School of Medicine, Stanford, California, United States of America
| | - Barbara Rangel
- Department of Ophthalmology, Stanford University, School of Medicine, Stanford, California, United States of America
| | - Laurel Stell
- Department of Biomedical Data Science, Stanford University, School of Medicine, Stanford, California, United States of America
| | - M. Ali Shariati
- Department of Ophthalmology, Stanford University, School of Medicine, Stanford, California, United States of America
| | - Roopa Dalal
- Department of Ophthalmology, Stanford University, School of Medicine, Stanford, California, United States of America
| | - Abinaya Nathan
- Department of Pulmonary Medicine, Stanford University, School of Medicine, Stanford, California, United States of America
| | - Ke Yuan
- Divisions of Pulmonary Medicine, Boston Children’s Hospital, Boston, Massachusetts, United States of America
| | - Vinicio de Jesus Perez
- Department of Pulmonary Medicine, Stanford University, School of Medicine, Stanford, California, United States of America
| | - Yaping Joyce Liao
- Department of Ophthalmology, Stanford University, School of Medicine, Stanford, California, United States of America
- Department of Neurology, Stanford University, School of Medicine, Stanford, California, United States of America
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Lambe J, Fitzgerald KC, Murphy OC, Filippatou AG, Sotirchos ES, Kalaitzidis G, Vasileiou E, Pellegrini N, Ogbuokiri E, Toliver B, Luciano NJ, Davis S, Fioravante N, Kwakyi O, Risher H, Crainiceanu CM, Prince JL, Newsome SD, Mowry EM, Saidha S, Calabresi PA. Association of Spectral-Domain OCT With Long-term Disability Worsening in Multiple Sclerosis. Neurology 2021; 96:e2058-e2069. [PMID: 33653904 DOI: 10.1212/wnl.0000000000011788] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Accepted: 01/19/2021] [Indexed: 12/12/2022] Open
Abstract
OBJECTIVE To evaluate whether a retinal spectral-domain optical coherence tomography (SD-OCT) assessment at baseline is associated with long-term disability worsening in people with multiple sclerosis (PwMS), we performed SD-OCT and Expanded Disability Status Scale (EDSS) assessments among 132 PwMS at baseline and at a median of 10 years later. METHODS In this prospective, longitudinal study, participants underwent SD-OCT, EDSS, and visual acuity (VA) assessments at baseline and at follow-up. Statistical analyses were performed using generalized linear regression models, adjusted for age, sex, race, multiple sclerosis (MS) subtype, and baseline disability. We defined clinically meaningful EDSS worsening as an increase of ≥2.0 if baseline EDSS score was <6.0 or an increase of ≥1.0 if baseline EDSS score was ≥6.0. RESULTS A total of 132 PwMS (mean age 43 years; 106 patients with relapsing-remitting MS) were included in analyses. Median duration of follow-up was 10.4 years. In multivariable models excluding eyes with prior optic neuritis, relative to patients with an average baseline ganglion cell + inner plexiform layer (GCIPL) thickness ≥70 µm (the mean GCIPL thickness of all eyes at baseline), an average baseline GCIPL thickness <70 µm was associated with a 4-fold increased odds of meaningful EDSS worsening (adjusted odds ratio [OR] 3.97, 95% confidence interval [CI] 1.24-12.70; p = 0.02) and an almost 3-fold increased odds of low-contrast VA worsening (adjusted OR 2.93, 95% CI 1.40-6.13; p = 0.04). CONCLUSIONS Lower baseline GCIPL thickness on SD-OCT is independently associated with long-term disability worsening in MS. Accordingly, SD-OCT at a single time point may help guide therapeutic decision-making among individual PwMS. CLASSIFICATION OF EVIDENCE This study provides Class I evidence that lower baseline GCIPL thickness on SD-OCT is independently associated with long-term disability worsening in MS.
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Affiliation(s)
- Jeffrey Lambe
- From the Department of Neurology (J.L., K.C.F., O.C.M., A.G.F., E.S.S., G.K., E.V., N.P., E.O., B.T., N.J.L., S.D., N.F., O.K., H.R., S.D.N., E.M.M., S.S., P.A.C.), Johns Hopkins University School of Medicine; and Departments of Biostatistics (C.M.C.) and Electrical and Computer Engineering (J.L.P.), Johns Hopkins University, Baltimore, MD
| | - Kathryn C Fitzgerald
- From the Department of Neurology (J.L., K.C.F., O.C.M., A.G.F., E.S.S., G.K., E.V., N.P., E.O., B.T., N.J.L., S.D., N.F., O.K., H.R., S.D.N., E.M.M., S.S., P.A.C.), Johns Hopkins University School of Medicine; and Departments of Biostatistics (C.M.C.) and Electrical and Computer Engineering (J.L.P.), Johns Hopkins University, Baltimore, MD
| | - Olwen C Murphy
- From the Department of Neurology (J.L., K.C.F., O.C.M., A.G.F., E.S.S., G.K., E.V., N.P., E.O., B.T., N.J.L., S.D., N.F., O.K., H.R., S.D.N., E.M.M., S.S., P.A.C.), Johns Hopkins University School of Medicine; and Departments of Biostatistics (C.M.C.) and Electrical and Computer Engineering (J.L.P.), Johns Hopkins University, Baltimore, MD
| | - Angeliki G Filippatou
- From the Department of Neurology (J.L., K.C.F., O.C.M., A.G.F., E.S.S., G.K., E.V., N.P., E.O., B.T., N.J.L., S.D., N.F., O.K., H.R., S.D.N., E.M.M., S.S., P.A.C.), Johns Hopkins University School of Medicine; and Departments of Biostatistics (C.M.C.) and Electrical and Computer Engineering (J.L.P.), Johns Hopkins University, Baltimore, MD
| | - Elias S Sotirchos
- From the Department of Neurology (J.L., K.C.F., O.C.M., A.G.F., E.S.S., G.K., E.V., N.P., E.O., B.T., N.J.L., S.D., N.F., O.K., H.R., S.D.N., E.M.M., S.S., P.A.C.), Johns Hopkins University School of Medicine; and Departments of Biostatistics (C.M.C.) and Electrical and Computer Engineering (J.L.P.), Johns Hopkins University, Baltimore, MD
| | - Grigorios Kalaitzidis
- From the Department of Neurology (J.L., K.C.F., O.C.M., A.G.F., E.S.S., G.K., E.V., N.P., E.O., B.T., N.J.L., S.D., N.F., O.K., H.R., S.D.N., E.M.M., S.S., P.A.C.), Johns Hopkins University School of Medicine; and Departments of Biostatistics (C.M.C.) and Electrical and Computer Engineering (J.L.P.), Johns Hopkins University, Baltimore, MD
| | - Elena Vasileiou
- From the Department of Neurology (J.L., K.C.F., O.C.M., A.G.F., E.S.S., G.K., E.V., N.P., E.O., B.T., N.J.L., S.D., N.F., O.K., H.R., S.D.N., E.M.M., S.S., P.A.C.), Johns Hopkins University School of Medicine; and Departments of Biostatistics (C.M.C.) and Electrical and Computer Engineering (J.L.P.), Johns Hopkins University, Baltimore, MD
| | - Nicole Pellegrini
- From the Department of Neurology (J.L., K.C.F., O.C.M., A.G.F., E.S.S., G.K., E.V., N.P., E.O., B.T., N.J.L., S.D., N.F., O.K., H.R., S.D.N., E.M.M., S.S., P.A.C.), Johns Hopkins University School of Medicine; and Departments of Biostatistics (C.M.C.) and Electrical and Computer Engineering (J.L.P.), Johns Hopkins University, Baltimore, MD
| | - Esther Ogbuokiri
- From the Department of Neurology (J.L., K.C.F., O.C.M., A.G.F., E.S.S., G.K., E.V., N.P., E.O., B.T., N.J.L., S.D., N.F., O.K., H.R., S.D.N., E.M.M., S.S., P.A.C.), Johns Hopkins University School of Medicine; and Departments of Biostatistics (C.M.C.) and Electrical and Computer Engineering (J.L.P.), Johns Hopkins University, Baltimore, MD
| | - Brandon Toliver
- From the Department of Neurology (J.L., K.C.F., O.C.M., A.G.F., E.S.S., G.K., E.V., N.P., E.O., B.T., N.J.L., S.D., N.F., O.K., H.R., S.D.N., E.M.M., S.S., P.A.C.), Johns Hopkins University School of Medicine; and Departments of Biostatistics (C.M.C.) and Electrical and Computer Engineering (J.L.P.), Johns Hopkins University, Baltimore, MD
| | - Nicholas J Luciano
- From the Department of Neurology (J.L., K.C.F., O.C.M., A.G.F., E.S.S., G.K., E.V., N.P., E.O., B.T., N.J.L., S.D., N.F., O.K., H.R., S.D.N., E.M.M., S.S., P.A.C.), Johns Hopkins University School of Medicine; and Departments of Biostatistics (C.M.C.) and Electrical and Computer Engineering (J.L.P.), Johns Hopkins University, Baltimore, MD
| | - Simidele Davis
- From the Department of Neurology (J.L., K.C.F., O.C.M., A.G.F., E.S.S., G.K., E.V., N.P., E.O., B.T., N.J.L., S.D., N.F., O.K., H.R., S.D.N., E.M.M., S.S., P.A.C.), Johns Hopkins University School of Medicine; and Departments of Biostatistics (C.M.C.) and Electrical and Computer Engineering (J.L.P.), Johns Hopkins University, Baltimore, MD
| | - Nicholas Fioravante
- From the Department of Neurology (J.L., K.C.F., O.C.M., A.G.F., E.S.S., G.K., E.V., N.P., E.O., B.T., N.J.L., S.D., N.F., O.K., H.R., S.D.N., E.M.M., S.S., P.A.C.), Johns Hopkins University School of Medicine; and Departments of Biostatistics (C.M.C.) and Electrical and Computer Engineering (J.L.P.), Johns Hopkins University, Baltimore, MD
| | - Ohemaa Kwakyi
- From the Department of Neurology (J.L., K.C.F., O.C.M., A.G.F., E.S.S., G.K., E.V., N.P., E.O., B.T., N.J.L., S.D., N.F., O.K., H.R., S.D.N., E.M.M., S.S., P.A.C.), Johns Hopkins University School of Medicine; and Departments of Biostatistics (C.M.C.) and Electrical and Computer Engineering (J.L.P.), Johns Hopkins University, Baltimore, MD
| | - Hunter Risher
- From the Department of Neurology (J.L., K.C.F., O.C.M., A.G.F., E.S.S., G.K., E.V., N.P., E.O., B.T., N.J.L., S.D., N.F., O.K., H.R., S.D.N., E.M.M., S.S., P.A.C.), Johns Hopkins University School of Medicine; and Departments of Biostatistics (C.M.C.) and Electrical and Computer Engineering (J.L.P.), Johns Hopkins University, Baltimore, MD
| | - Ciprian M Crainiceanu
- From the Department of Neurology (J.L., K.C.F., O.C.M., A.G.F., E.S.S., G.K., E.V., N.P., E.O., B.T., N.J.L., S.D., N.F., O.K., H.R., S.D.N., E.M.M., S.S., P.A.C.), Johns Hopkins University School of Medicine; and Departments of Biostatistics (C.M.C.) and Electrical and Computer Engineering (J.L.P.), Johns Hopkins University, Baltimore, MD
| | - Jerry L Prince
- From the Department of Neurology (J.L., K.C.F., O.C.M., A.G.F., E.S.S., G.K., E.V., N.P., E.O., B.T., N.J.L., S.D., N.F., O.K., H.R., S.D.N., E.M.M., S.S., P.A.C.), Johns Hopkins University School of Medicine; and Departments of Biostatistics (C.M.C.) and Electrical and Computer Engineering (J.L.P.), Johns Hopkins University, Baltimore, MD
| | - Scott D Newsome
- From the Department of Neurology (J.L., K.C.F., O.C.M., A.G.F., E.S.S., G.K., E.V., N.P., E.O., B.T., N.J.L., S.D., N.F., O.K., H.R., S.D.N., E.M.M., S.S., P.A.C.), Johns Hopkins University School of Medicine; and Departments of Biostatistics (C.M.C.) and Electrical and Computer Engineering (J.L.P.), Johns Hopkins University, Baltimore, MD
| | - Ellen M Mowry
- From the Department of Neurology (J.L., K.C.F., O.C.M., A.G.F., E.S.S., G.K., E.V., N.P., E.O., B.T., N.J.L., S.D., N.F., O.K., H.R., S.D.N., E.M.M., S.S., P.A.C.), Johns Hopkins University School of Medicine; and Departments of Biostatistics (C.M.C.) and Electrical and Computer Engineering (J.L.P.), Johns Hopkins University, Baltimore, MD
| | - Shiv Saidha
- From the Department of Neurology (J.L., K.C.F., O.C.M., A.G.F., E.S.S., G.K., E.V., N.P., E.O., B.T., N.J.L., S.D., N.F., O.K., H.R., S.D.N., E.M.M., S.S., P.A.C.), Johns Hopkins University School of Medicine; and Departments of Biostatistics (C.M.C.) and Electrical and Computer Engineering (J.L.P.), Johns Hopkins University, Baltimore, MD
| | - Peter A Calabresi
- From the Department of Neurology (J.L., K.C.F., O.C.M., A.G.F., E.S.S., G.K., E.V., N.P., E.O., B.T., N.J.L., S.D., N.F., O.K., H.R., S.D.N., E.M.M., S.S., P.A.C.), Johns Hopkins University School of Medicine; and Departments of Biostatistics (C.M.C.) and Electrical and Computer Engineering (J.L.P.), Johns Hopkins University, Baltimore, MD.
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Lowry EA, Mansberger SL, Gardiner SK, Yang H, Sanchez F, Reynaud J, Demirel S, Burgoyne CF, Fortune B. Association of Optic Nerve Head Prelaminar Schisis With Glaucoma. Am J Ophthalmol 2021; 223:246-258. [PMID: 33166501 DOI: 10.1016/j.ajo.2020.10.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 10/24/2020] [Accepted: 10/27/2020] [Indexed: 12/28/2022]
Abstract
PURPOSE To compare the frequency of observing optic nerve head (ONH) prelaminar schisis by optical coherence tomography (OCT) in glaucoma and glaucoma suspect (GL/S) eyes vs healthy control (HC) eyes and to assess its association with other markers of glaucoma severity. METHODS This cross-sectional study included 298 eyes of 150 GL/S patients and 88 eyes of 44 HCs. OCT scans were obtained, including 24 radial B-scans, each composed of 768 A-lines spanning 15°, centered on the ONH. Two reviewers masked to all other clinical, demographic, and ocular information independently graded the OCT scans for the presence of ONH prelaminar schisis on a 4-point scale of 0 (none) to 3 (severe). The probability of ONH schisis was compared between groups and against demographic and ocular factors, including structural and functional measures of glaucoma severity. RESULTS The frequency and severity of ONH prelaminar schisis were greater in GL/S than in HC (P = .009). Among the GL/S group, 165 eyes (55.4%) had no visible schisis (Grade 0), 71 (23.8%) had Grade 1, 46 (15.4%) had Grade 2 and 16 (5.4%) had Grade 3 schisis. Among HC eyes, 59 (67.0%) had Grade 0, 24 (27.3%) had Grade 1, 5 (5.7%) had Grade 2, none had Grade 3. ONH schisis was more common in eyes with thinner MRW and a deeper cup. CONCLUSIONS ONH prelaminar schisis may be a sign of glaucomatous deformation and reflect ongoing pathophysiological damage. ONH prelaminar schisis can impact OCT image segmentation and diagnostic parameters, resulting in substantial overestimation of the true rim tissue thickness and underestimation of cup depth.
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Kimball E, Schaub J, Quillen S, Keuthan C, Pease ME, Korneva A, Quigley H. The role of aquaporin-4 in optic nerve head astrocytes in experimental glaucoma. PLoS One 2021; 16:e0244123. [PMID: 33529207 PMCID: PMC7853498 DOI: 10.1371/journal.pone.0244123] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 01/11/2021] [Indexed: 02/04/2023] Open
Abstract
PURPOSE To study aquaporin channel expression in astrocytes of the mouse optic nerve (ON) and the response to IOP elevation in mice lacking aquaporin 4 (AQP4 null). METHODS C57BL/6 (B6) and AQP4 null mice were exposed to bead-induced IOP elevation for 3 days (3D-IOP), 1 and 6 weeks. Mouse ocular tissue sections were immunolabeled against aquaporins 1(AQP1), 4(AQP4), and 9(AQP9). Ocular tissue was imaged to identify normal AQP distribution, ON changes, and axon loss after IOP elevation. Ultrastructure examination, cell proliferation, gene expression, and transport block were also analyzed. RESULTS B6 mice had abundant AQP4 expression in Müller cells, astrocytes of retina and myelinated ON (MON), but minimal AQP4in prelaminar and unmyelinated ON (UON). MON of AQP4 nulls had smaller ON area, smaller axon diameter, higher axon density, and larger proportionate axon area than B6 (all p≤0.05). Bead-injection led to comparable 3D-IOP elevation (p = 0.42) and axonal transport blockade in both strains. In B6, AQP4 distribution was unchanged after 3D-IOP. At baseline, AQP1 and AQP9 were present in retina, but not in UON and this was unaffected after IOP elevation in both strains. In 3D-IOP mice, ON astrocytes and microglia proliferated, more in B6 than AQP4 null. After 6 week IOP elevation, axon loss occurred equally in the two mouse types (24.6%, AQP4 null vs. 23.3%, B6). CONCLUSION Lack of AQP4 was neither protective nor detrimental to the effects of IOP elevation. The minimal presence of AQP4 in UON may be a vital aspect of the regionally specific phenotype of astrocytes in the mouse optic nerve head.
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Affiliation(s)
- Elizabeth Kimball
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Julie Schaub
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Sarah Quillen
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Casey Keuthan
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Mary Ellen Pease
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Arina Korneva
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Harry Quigley
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
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50
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Filippatou AG, Vasileiou ES, He Y, Fitzgerald KC, Kalaitzidis G, Lambe J, Mealy MA, Levy M, Liu Y, Prince JL, Mowry EM, Saidha S, Calabresi PA, Sotirchos ES. Evidence of subclinical quantitative retinal layer abnormalities in AQP4-IgG seropositive NMOSD. Mult Scler 2020; 27:1738-1748. [PMID: 33307967 DOI: 10.1177/1352458520977771] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
BACKGROUND Prior studies have suggested that subclinical retinal abnormalities may be present in aquaporin-4 immunoglobulin G (AQP4-IgG) seropositive neuromyelitis optica spectrum disorder (NMOSD), in the absence of a clinical history of optic neuritis (ON). OBJECTIVE Our aim was to compare retinal layer thicknesses at the fovea and surrounding macula between AQP4-IgG+ NMOSD eyes without a history of ON (AQP4-nonON) and healthy controls (HC). METHODS In this single-center cross-sectional study, 83 AQP4-nonON and 154 HC eyes were studied with spectral-domain optical coherence tomography (OCT). RESULTS Total foveal thickness did not differ between AQP4-nonON and HC eyes. AQP4-nonON eyes exhibited lower outer nuclear layer (ONL) and inner photoreceptor segment (IS) thickness at the fovea (ONL: -4.01 ± 2.03 μm, p = 0.049; IS: -0.32 ± 0.14 μm, p = 0.029) and surrounding macula (ONL: -1.98 ± 0.95 μm, p = 0.037; IS: -0.16 ± 0.07 μm, p = 0.023), compared to HC. Macular retinal nerve fiber layer (RNFL: -1.34 ± 0.51 μm, p = 0.009) and ganglion cell + inner plexiform layer (GCIPL: -2.44 ± 0.93 μm, p = 0.009) thicknesses were also lower in AQP4-nonON compared to HC eyes. Results were similar in sensitivity analyses restricted to AQP4-IgG+ patients who had never experienced ON in either eye. CONCLUSIONS AQP4-nonON eyes exhibit evidence of subclinical retinal ganglion cell neuronal and axonal loss, as well as structural evidence of photoreceptor layer involvement. These findings support that subclinical anterior visual pathway involvement may occur in AQP4-IgG+ NMOSD.
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Affiliation(s)
- Angeliki G Filippatou
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Eleni S Vasileiou
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Yufan He
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Kathryn C Fitzgerald
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Grigorios Kalaitzidis
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jeffrey Lambe
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Maureen A Mealy
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA/Viela Bio, Gaithersburg, MD, USA
| | - Michael Levy
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Yihao Liu
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Jerry L Prince
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Ellen M Mowry
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Shiv Saidha
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Peter A Calabresi
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Elias S Sotirchos
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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