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van Koeverden AK, Afiat BC, Nguyen CT, Bui BV, Lee PY. Understanding how ageing impacts ganglion cell susceptibility to injury in glaucoma. Clin Exp Optom 2024; 107:147-155. [PMID: 37980904 DOI: 10.1080/08164622.2023.2279734] [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: 06/17/2023] [Accepted: 10/31/2023] [Indexed: 11/21/2023] Open
Abstract
Glaucoma is a leading cause of blindness worldwide, with a marked increase in prevalence with advancing age. Due to the multifactorial nature of glaucoma pathogenesis, dissecting how ageing impacts upon glaucoma risk requires analysis and synthesis of evidence from a vast literature. While there is a wealth of human clinical studies examining glaucoma pathogenesis and why older patients have increased risk, many aspects of the disease such as adaptations of retinal ganglion cells to stress, autophagy and the role of glial cells in glaucoma, require the use of animal models to study the complex cellular processes and interactions. Additionally, the accelerated nature of ageing in rodents facilitates the longitudinal study of changes that would not be feasible in human clinical studies. This review article examines evidence derived predominantly from rodent models on how the ageing process impacts upon various aspects of glaucoma pathology from the retinal ganglion cells themselves, to supporting cells and tissues such as glial cells, connective tissue and vasculature, in addition to oxidative stress and autophagy. An improved understanding of how ageing modifies these factors may lead to the development of different therapeutic strategies that target specific risk factors or processes involved in glaucoma.
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Affiliation(s)
- Anna K van Koeverden
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Brianna C Afiat
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Christine To Nguyen
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Bang V Bui
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Pei Ying Lee
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia
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Soucy JR, Aguzzi EA, Cho J, Gilhooley MJ, Keuthan C, Luo Z, Monavarfeshani A, Saleem MA, Wang XW, Wohlschlegel J, Baranov P, Di Polo A, Fortune B, Gokoffski KK, Goldberg JL, Guido W, Kolodkin AL, Mason CA, Ou Y, Reh TA, Ross AG, Samuels BC, Welsbie D, Zack DJ, Johnson TV. Retinal ganglion cell repopulation for vision restoration in optic neuropathy: a roadmap from the RReSTORe Consortium. Mol Neurodegener 2023; 18:64. [PMID: 37735444 PMCID: PMC10514988 DOI: 10.1186/s13024-023-00655-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 09/07/2023] [Indexed: 09/23/2023] Open
Abstract
Retinal ganglion cell (RGC) death in glaucoma and other optic neuropathies results in irreversible vision loss due to the mammalian central nervous system's limited regenerative capacity. RGC repopulation is a promising therapeutic approach to reverse vision loss from optic neuropathies if the newly introduced neurons can reestablish functional retinal and thalamic circuits. In theory, RGCs might be repopulated through the transplantation of stem cell-derived neurons or via the induction of endogenous transdifferentiation. The RGC Repopulation, Stem Cell Transplantation, and Optic Nerve Regeneration (RReSTORe) Consortium was established to address the challenges associated with the therapeutic repair of the visual pathway in optic neuropathy. In 2022, the RReSTORe Consortium initiated ongoing international collaborative discussions to advance the RGC repopulation field and has identified five critical areas of focus: (1) RGC development and differentiation, (2) Transplantation methods and models, (3) RGC survival, maturation, and host interactions, (4) Inner retinal wiring, and (5) Eye-to-brain connectivity. Here, we discuss the most pertinent questions and challenges that exist on the path to clinical translation and suggest experimental directions to propel this work going forward. Using these five subtopic discussion groups (SDGs) as a framework, we suggest multidisciplinary approaches to restore the diseased visual pathway by leveraging groundbreaking insights from developmental neuroscience, stem cell biology, molecular biology, optical imaging, animal models of optic neuropathy, immunology & immunotolerance, neuropathology & neuroprotection, materials science & biomedical engineering, and regenerative neuroscience. While significant hurdles remain, the RReSTORe Consortium's efforts provide a comprehensive roadmap for advancing the RGC repopulation field and hold potential for transformative progress in restoring vision in patients suffering from optic neuropathies.
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Affiliation(s)
- Jonathan R Soucy
- Department of Ophthalmology, Schepens Eye Research Institute of Mass. Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Erika A Aguzzi
- The Institute of Ophthalmology, University College London, London, England, UK
| | - Julie Cho
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Michael James Gilhooley
- The Institute of Ophthalmology, University College London, London, England, UK
- Moorfields Eye Hospital, London, England, UK
| | - Casey Keuthan
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ziming Luo
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Aboozar Monavarfeshani
- Center for Brain Science and Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
- Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA
| | - Meher A Saleem
- Bascom Palmer Eye Institute, University of Miami Health System, Miami, FL, USA
| | - Xue-Wei Wang
- Department of Orthopaedic Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | | | - Petr Baranov
- Department of Ophthalmology, Schepens Eye Research Institute of Mass. Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Adriana Di Polo
- Department of Neuroscience, University of Montreal, Montreal, QC, Canada
- University of Montreal Hospital Research Centre, Montreal, QC, Canada
| | - Brad Fortune
- Discoveries in Sight Research Laboratories, Devers Eye Institute and Legacy Research Institute, Legacy Health, Portland, OR, USA
| | - Kimberly K Gokoffski
- Department of Ophthalmology, Roski Eye Institute, University of Southern California, Los Angeles, CA, USA
| | - Jeffrey L Goldberg
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - William Guido
- Department of Anatomical Sciences and Neurobiology, School of Medicine, University of Louisville, Louisville, KY, USA
| | - Alex L Kolodkin
- The Solomon H Snyder, Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Carol A Mason
- Departments of Pathology and Cell Biology, Neuroscience, and Ophthalmology, College of Physicians and Surgeons, Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | - Yvonne Ou
- Department of Ophthalmology, University of California, San Francisco, CA, USA
| | - Thomas A Reh
- Department of Biological Structure, University of Washington, Seattle, WA, USA
| | - Ahmara G Ross
- Departments of Ophthalmology and Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Brian C Samuels
- Department of Ophthalmology and Visual Sciences, Callahan Eye Hospital, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Derek Welsbie
- Shiley Eye Institute and Viterbi Family Department of Ophthalmology, University of California, San Diego, CA, USA
| | - Donald J Zack
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, 21287 MD, USA
- Departments of Neuroscience, Molecular Biology & Genetics, and Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Thomas V Johnson
- Departments of Neuroscience, Molecular Biology & Genetics, and Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- Cellular & Molecular Medicine Program, Johns Hopkins University School of Medicine, Baltimore, 21287 MD, USA.
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3
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Sikiric P, Kokot A, Kralj T, Zlatar M, Masnec S, Lazic R, Loncaric K, Oroz K, Sablic M, Boljesic M, Antunovic M, Sikiric S, Strbe S, Stambolija V, Beketic Oreskovic L, Kavelj I, Novosel L, Zubcic S, Krezic I, Skrtic A, Jurjevic I, Boban Blagaic A, Seiwerth S, Staresinic M. Stable Gastric Pentadecapeptide BPC 157-Possible Novel Therapy of Glaucoma and Other Ocular Conditions. Pharmaceuticals (Basel) 2023; 16:1052. [PMID: 37513963 PMCID: PMC10385428 DOI: 10.3390/ph16071052] [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: 05/05/2023] [Revised: 07/01/2023] [Accepted: 07/20/2023] [Indexed: 07/30/2023] Open
Abstract
Recently, stable gastric pentadecapeptide BPC 157 therapy by activation of collateral pathways counteracted various occlusion/occlusion-like syndromes, vascular, and multiorgan failure, and blood pressure disturbances in rats with permanent major vessel occlusion and similar procedures disabling endothelium function. Thereby, we revealed BPC 157 cytoprotective therapy with strong vascular rescuing capabilities in glaucoma therapy. With these capabilities, BPC 157 therapy can recover glaucomatous rats, normalize intraocular pressure, maintain retinal integrity, recover pupil function, recover retinal ischemia, and corneal injuries (i.e., maintained transparency after complete corneal abrasion, corneal ulceration, and counteracted dry eye after lacrimal gland removal or corneal insensitivity). The most important point is that in glaucomatous rats (three of four episcleral veins cauterized) with high intraocular pressure, all BPC 157 regimens immediately normalized intraocular pressure. BPC 157-treated rats exhibited normal pupil diameter, microscopically well-preserved ganglion cells and optic nerve presentation, normal fundus presentation, nor- mal retinal and choroidal blood vessel presentation, and normal optic nerve presentation. The one episcleral vein rapidly upgraded to accomplish all functions in glaucomatous rats may correspond with occlusion/occlusion-like syndromes of the activated rescuing collateral pathway (azygos vein direct blood flow delivery). Normalized intraocular pressure in glaucomatous rats corresponded to the counteracted intra-cranial (superior sagittal sinus), portal, and caval hypertension, and aortal hypotension in occlusion/occlusion-like syndromes, were all attenuated/eliminated by BPC 157 therapy. Furthermore, given in other eye disturbances (i.e., retinal ischemia), BPC 157 instantly breaks a noxious chain of events, both at an early stage and an already advanced stage. Thus, we further advocate BPC 157 as a therapeutic agent in ocular disease.
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Affiliation(s)
- Predrag Sikiric
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Antonio Kokot
- Department of Anatomy and Neuroscience, Faculty of Medicine, J.J. Strossmayer University of Osijek, 31000 Osijek, Croatia
| | - Tamara Kralj
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Mirna Zlatar
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Sanja Masnec
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Ratimir Lazic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Kristina Loncaric
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Katarina Oroz
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Marko Sablic
- Department of Anatomy and Neuroscience, Faculty of Medicine, J.J. Strossmayer University of Osijek, 31000 Osijek, Croatia
| | - Marta Boljesic
- Department of Anatomy and Neuroscience, Faculty of Medicine, J.J. Strossmayer University of Osijek, 31000 Osijek, Croatia
| | - Marko Antunovic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Suncana Sikiric
- Department of Pathology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Sanja Strbe
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Vasilije Stambolija
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | | | - Ivana Kavelj
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Luka Novosel
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Slavica Zubcic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Ivan Krezic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Anita Skrtic
- Department of Pathology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Ivana Jurjevic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Alenka Boban Blagaic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Sven Seiwerth
- Department of Pathology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Mario Staresinic
- Department of Surgery, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
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Mathew DJ, Livne-Bar I, Sivak JM. An inducible rodent glaucoma model that exhibits gradual sustained increase in intraocular pressure with distinct inner retina and optic nerve inflammation. Sci Rep 2021; 11:22880. [PMID: 34819548 PMCID: PMC8613281 DOI: 10.1038/s41598-021-02057-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 11/09/2021] [Indexed: 01/29/2023] Open
Abstract
Glaucoma is a chronic and progressive neurodegenerative disease of the optic nerve resulting in loss of retinal ganglion cells (RGCs) and vision. The most prominent glaucoma risk factor is increased intraocular pressure (IOP), and most models focus on reproducing this aspect to study disease mechanisms and targets. Yet, current models result in IOP profiles that often do not resemble clinical glaucoma. Here we introduce a new model that results in a gradual and sustained IOP increase over time. This approach modifies a circumlimbal suture method, taking care to make the sutures 'snug' instead of tight, without inducing an initial IOP spike. This approach did not immediately affect IOPs, but generated gradual ocular hypertension (gOHT) as the sutures tighten over time, in comparison to loosely sutured control eyes (CON), resulting in an average 12.6 mmHg increase in IOP at 17 weeks (p < 0.001). Corresponding characterization revealed relevant retinal and optic nerve pathology, such as thinning of the retinal nerve fiber layer, decreased optokinetic response, RGC loss, and optic nerve head remodeling. Yet, angles remained open, with no evidence of inflammation. Corresponding biochemical profiling indicated significant increases in TGF-β2 and 3, and IL-1 family cytokines in gOHT optic nerve tissues compared to CON, with accompanying microglial reactivity, consistent with active tissue injury and repair mechanisms. Remarkably, this signature was absent from optic nerves following acute ocular hypertension (aOHT) associated with intentionally tightened sutures, although the resulting RGC loss was similar in both methods. These results suggest that the pattern of IOP change has an important impact on underlying pathophysiology.
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Affiliation(s)
- David J Mathew
- Donald K. Johnson Eye Institute, Krembil Research Institute, University Health Network, Toronto, ON, Canada
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON, Canada
- Department of Lab Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Izhar Livne-Bar
- Donald K. Johnson Eye Institute, Krembil Research Institute, University Health Network, Toronto, ON, Canada
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON, Canada
- Department of Lab Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Jeremy M Sivak
- Donald K. Johnson Eye Institute, Krembil Research Institute, University Health Network, Toronto, ON, Canada.
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON, Canada.
- Department of Lab Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.
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5
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Liu Z, Saeedi O, Zhang F, Villanueva R, Asanad S, Agrawal A, Hammer DX. Quantification of Retinal Ganglion Cell Morphology in Human Glaucomatous Eyes. Invest Ophthalmol Vis Sci 2021; 62:34. [PMID: 33760041 PMCID: PMC7995922 DOI: 10.1167/iovs.62.3.34] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Purpose To characterize retinal ganglion cell morphological changes in patients with primary open-angle glaucoma associated with hemifield defect (HD) using adaptive optics–optical coherence tomography (AO-OCT). Methods Six patients with early to moderate primary open-angle glaucoma with an average age of 58 years associated with HD and six age-matched healthy controls with an average age of 61 years were included. All participants underwent in vivo retinal ganglion cell (RGC) imaging at six primary locations across the macula with AO-OCT. Ganglion cell layer (GCL) somas were manually counted, and morphological parameters of GCL soma density, size, and symmetry were calculated. RGC cellular characteristics were correlated with functional visual field measurements. Results GCL soma density was 12,799 ± 7747 cells/mm2, 9370 ± 5572 cells/mm2, and 2134 ± 1494 cells/mm2 at 3°, 6°, and 12°, respectively, in glaucoma patients compared with 25,058 ± 4649 cells/mm2, 15,551 ± 2301 cells/mm2, and 3891 ± 1105 cells/mm2 (P < 0.05 for all locations) at the corresponding retinal locations in healthy participants. Mean soma diameter was significantly larger in glaucoma patients (14.20 ± 2.30 µm) compared with the health controls (12.32 ± 1.94 µm, P < 0.05 for all locations); symmetry was 0.36 ± 0.32 and 0.86 ± 0.13 in glaucoma and control cohorts, respectively. Conclusions Glaucoma patients had lower GCL soma density and symmetry, greater soma size, and increased variation of GCL soma reflectance compared with age-matched control subjects. The morphological changes corresponded with HD, and the cellular level structural loss correlated with visual function loss in glaucoma. AO-based morphological parameters could be potential sensitive biomarkers for glaucoma.
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Affiliation(s)
- Zhuolin Liu
- Center for Devices and Radiological Health (CDRH), U.S. Food and Drug Administration, Silver Spring, Maryland, United States
| | - Osamah Saeedi
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore Maryland, United States
| | - Furu Zhang
- Center for Devices and Radiological Health (CDRH), U.S. Food and Drug Administration, Silver Spring, Maryland, United States
| | - Ricardo Villanueva
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore Maryland, United States
| | - Samuel Asanad
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore Maryland, United States
| | - Anant Agrawal
- Center for Devices and Radiological Health (CDRH), U.S. Food and Drug Administration, Silver Spring, Maryland, United States
| | - Daniel X Hammer
- Center for Devices and Radiological Health (CDRH), U.S. Food and Drug Administration, Silver Spring, Maryland, United States
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Tribble JR, Hui F, Jöe M, Bell K, Chrysostomou V, Crowston JG, Williams PA. Targeting Diet and Exercise for Neuroprotection and Neurorecovery in Glaucoma. Cells 2021; 10:295. [PMID: 33535578 PMCID: PMC7912764 DOI: 10.3390/cells10020295] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/15/2021] [Accepted: 01/28/2021] [Indexed: 12/11/2022] Open
Abstract
Glaucoma is a leading cause of blindness worldwide. In glaucoma, a progressive dysfunction and death of retinal ganglion cells occurs, eliminating transfer of visual information to the brain. Currently, the only available therapies target the lowering of intraocular pressure, but many patients continue to lose vision. Emerging pre-clinical and clinical evidence suggests that metabolic deficiencies and defects may play an important role in glaucoma pathophysiology. While pre-clinical studies in animal models have begun to mechanistically uncover these metabolic changes, some existing clinical evidence already points to potential benefits in maintaining metabolic fitness. Modifying diet and exercise can be implemented by patients as an adjunct to intraocular pressure lowering, which may be of therapeutic benefit to retinal ganglion cells in glaucoma.
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Affiliation(s)
- James R. Tribble
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, 171 64 Stockholm, Sweden; (J.R.T.); (M.J.)
| | - Flora Hui
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, VIC 3002, Australia; (F.H.); (J.G.C.)
- Department of Optometry & Vision Sciences, The University of Melbourne, Melbourne, VIC 3053, Australia
| | - Melissa Jöe
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, 171 64 Stockholm, Sweden; (J.R.T.); (M.J.)
| | - Katharina Bell
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore 168751, Singapore; (K.B.); (V.C.)
| | - Vicki Chrysostomou
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore 168751, Singapore; (K.B.); (V.C.)
- Duke-NUS Medical School, Singapore 169857, Singapore
| | - Jonathan G. Crowston
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, VIC 3002, Australia; (F.H.); (J.G.C.)
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore 168751, Singapore; (K.B.); (V.C.)
- Duke-NUS Medical School, Singapore 169857, Singapore
| | - Pete A. Williams
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, 171 64 Stockholm, Sweden; (J.R.T.); (M.J.)
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Davis BM, Guo L, Ravindran N, Shamsher E, Baekelandt V, Mitchell H, Bharath AA, De Groef L, Cordeiro MF. Dynamic changes in cell size and corresponding cell fate after optic nerve injury. Sci Rep 2020; 10:21683. [PMID: 33303775 PMCID: PMC7730151 DOI: 10.1038/s41598-020-77760-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 11/10/2020] [Indexed: 01/21/2023] Open
Abstract
Identifying disease-specific patterns of retinal cell loss in pathological conditions has been highlighted by the emergence of techniques such as Detection of Apoptotic Retinal Cells and Adaptive Optics confocal Scanning Laser Ophthalmoscopy which have enabled single-cell visualisation in vivo. Cell size has previously been used to stratify Retinal Ganglion Cell (RGC) populations in histological samples of optic neuropathies, and early work in this field suggested that larger RGCs are more susceptible to early loss than smaller RGCs. More recently, however, it has been proposed that RGC soma and axon size may be dynamic and change in response to injury. To address this unresolved controversy, we applied recent advances in maximising information extraction from RGC populations in retinal whole mounts to evaluate the changes in RGC size distribution over time, using three well-established rodent models of optic nerve injury. In contrast to previous studies based on sampling approaches, we examined the whole Brn3a-positive RGC population at multiple time points over the natural history of these models. The morphology of over 4 million RGCs was thus assessed to glean novel insights from this dataset. RGC subpopulations were found to both increase and decrease in size over time, supporting the notion that RGC cell size is dynamic in response to injury. However, this study presents compelling evidence that smaller RGCs are lost more rapidly than larger RGCs despite the dynamism. Finally, using a bootstrap approach, the data strongly suggests that disease-associated changes in RGC spatial distribution and morphology could have potential as novel diagnostic indicators.
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Affiliation(s)
- Benjamin M Davis
- Institute of Ophthalmology, University College London, 11-43 Bath Street, London, EC1V 9EL, UK
- Western Eye Hospital, ICORG, Imperial College London, London, NW1 5QH, UK
| | - Li Guo
- Institute of Ophthalmology, University College London, 11-43 Bath Street, London, EC1V 9EL, UK
| | - Nivedita Ravindran
- Institute of Ophthalmology, University College London, 11-43 Bath Street, London, EC1V 9EL, UK
| | - Ehtesham Shamsher
- Institute of Ophthalmology, University College London, 11-43 Bath Street, London, EC1V 9EL, UK
| | - Veerle Baekelandt
- Laboratory for Neurobiology and Gene Therapy, Department of Neurosciences, KU Leuven, Kapucijnenvoer 33, 3000, Leuven, Belgium
| | - Hannah Mitchell
- School of Mathematics and Physics, Queens University Belfast, Belfast, Ireland
| | - Anil A Bharath
- Department of Bioengineering, Imperial College London, South Kensington Campus, London, UK
| | - Lies De Groef
- Neural Circuit Development and Regeneration Research Group, Department of Biology, KU Leuven, Naamsestraat 61, 3000, Leuven, Belgium.
| | - M Francesca Cordeiro
- Institute of Ophthalmology, University College London, 11-43 Bath Street, London, EC1V 9EL, UK.
- Western Eye Hospital, ICORG, Imperial College London, London, NW1 5QH, UK.
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8
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Elevated Intraocular Pressure Causes Abnormal Reactivity of Mouse Retinal Arterioles. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:9736047. [PMID: 31976030 PMCID: PMC6954472 DOI: 10.1155/2019/9736047] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 10/27/2019] [Accepted: 11/27/2019] [Indexed: 11/20/2022]
Abstract
Objective Glaucoma is a leading cause of severe visual impairment and blindness. Although high intraocular pressure (IOP) is an established risk factor for the disease, the role of abnormal ocular vessel function in the pathophysiology of glaucoma gains more and more attention. We tested the hypothesis that elevated intraocular pressure (IOP) causes vascular dysfunction in the retina. Methods High IOP was induced in one group of mice by unilateral cauterization of three episcleral veins. The other group received sham surgery only. Two weeks later, retinal vascular preparations were studied by video microscopy in vitro. Reactive oxygen species (ROS) levels and expression of hypoxia markers and of prooxidant and antioxidant redox genes as well as of inflammatory cytokines were determined. Results Strikingly, responses of retinal arterioles to stepwise elevation of perfusion pressure were impaired in the high-IOP group. Moreover, vasodilation responses to the endothelium-dependent vasodilator, acetylcholine, were markedly reduced in mice with elevated IOP, while no differences were seen in response to the endothelium-independent nitric oxide donor, sodium nitroprusside. Remarkably, ROS levels were increased in the retinal ganglion cell layer including blood vessels. Expression of the NADPH oxidase isoform, NOX2, and of the inflammatory cytokine, TNF-α, was increased at the mRNA level in retinal explants. Expression of NOX2, but not of the hypoxic markers, HIF-1α and VEGF-A, was increased in the retinal ganglion cell layer and in retinal blood vessels at the protein level. Conclusion Our data provide first-time evidence that IOP elevation impairs autoregulation and induces endothelial dysfunction in mouse retinal arterioles. Oxidative stress and inflammation, but not hypoxia, appear to be involved in this process.
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9
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Ogata NG, Boer ER, Daga FB, Jammal AA, Stringham JM, Medeiros FA. Visual Crowding in Glaucoma. Invest Ophthalmol Vis Sci 2019; 60:538-543. [PMID: 30716149 PMCID: PMC6361551 DOI: 10.1167/iovs.18-25150] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Crowding refers to the phenomenon in which objects that can be recognized when viewed in isolation are unrecognizable in clutter. Crowding sets a fundamental limit to the capabilities of the peripheral vision and is essential in explaining performance in a broad array of daily tasks. Due to the effects of glaucoma on peripheral vision, we hypothesized that neural loss in the disease would lead to stronger effects of visual crowding. Methods Subjects were asked to discriminate the orientation of a target letter when presented with surrounding flankers. The critical spacing value (scritical), which was required for correct discrimination of letter orientation, was obtained for each quadrant of the visual field. scritical values were correlated with standard automated perimetry (SAP) mean sensitivity (MS) and optical coherence tomography (OCT) retinal nerve fiber layer (RNFL) thickness measurements. Results The study involved 13 subjects with mild glaucomatous visual field loss and 13 healthy controls. Glaucomatous eyes had significantly greater (worse) scritical than controls (170.4 ± 27.1 vs. 145.8 ± 28.0 minimum of visual angle, respectively; P = 0.007). scritical measurements were significantly associated with RNFL thickness measurements (R2 = 26%; P < 0.001) but not with SAP MS (P = 0.947). Conclusions In glaucoma patients, a pronounced visual crowding effect is observed, even in the presence of mild visual field loss on standard perimetry. scritical was associated with the amount of neural loss quantified by OCT. These results may have implications for understanding how glaucoma patients are affected in daily tasks where crowding effects may be significant.
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Affiliation(s)
- Nara G Ogata
- Duke Eye Center, Department of Ophthalmology, Duke University, Durham, North Carolina, United States
| | - Erwin R Boer
- Entropy Control, La Jolla, California, United States
| | - Fábio B Daga
- Duke Eye Center, Department of Ophthalmology, Duke University, Durham, North Carolina, United States
| | - Alessandro A Jammal
- Duke Eye Center, Department of Ophthalmology, Duke University, Durham, North Carolina, United States
| | - James M Stringham
- Duke Eye Center, Department of Ophthalmology, Duke University, Durham, North Carolina, United States
| | - Felipe A Medeiros
- Duke Eye Center, Department of Ophthalmology, Duke University, Durham, North Carolina, United States
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10
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Biswas S, Wan KH. Review of rodent hypertensive glaucoma models. Acta Ophthalmol 2019; 97:e331-e340. [PMID: 30549197 DOI: 10.1111/aos.13983] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 11/04/2018] [Indexed: 12/11/2022]
Abstract
Glaucoma is a neurodegenerative disease characterized by the progressive loss of retinal ganglion cells (RGCs). Elevated intraocular pressure (IOP) is a primary risk factor for the development and progression of glaucoma. Rodent models of glaucoma have greatly improved our understanding of the pathophysiology of glaucoma and served as a useful tool to investigate neuroprotective agents. An ideal glaucoma animal model should be easy to induce, reproducible, biologically plausible and predictable. Of the available animal models of glaucoma, rodents are commonly studied because they have a relatively short life span and can be genetically altered. A successful hypertensive glaucoma model should induce structural glaucomatous changes: including loss of retinal nerve fibres, retinal ganglion cells and optic-disc cupping along with IOP elevation. The level and duration of IOP elevation should be titratable depending on the targeted glaucomatous damage. This review summarizes the outcomes of induced rodent hypertensive glaucoma models including intracameral injection of microbeads, laser photocoagulation, episcleral vein cauterization, injection of hypertonic saline and hyaluronic acid. We aim to provide a detailed overview of each of the models with a focus on parameters that defines a successful glaucoma model. The induced IOP elevation and duration of elevation varied among the different models and strain of rodent; nonetheless, they all achieved a sustainable raised IOP with corresponding RGC loss. The limitations of each model are discussed.
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Affiliation(s)
- Sayantan Biswas
- Department of Optometry NSHM Knowledge Campus Maulana Abul Kalam Azad University of Technology Kolkata India
| | - Kelvin H. Wan
- Department of Ophthalmology & Visual Sciences Chinese University of Hong Kong Hong Kong Hong Kong
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11
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Fry LE, Fahy E, Chrysostomou V, Hui F, Tang J, van Wijngaarden P, Petrou S, Crowston JG. The coma in glaucoma: Retinal ganglion cell dysfunction and recovery. Prog Retin Eye Res 2018; 65:77-92. [DOI: 10.1016/j.preteyeres.2018.04.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 03/18/2018] [Accepted: 04/03/2018] [Indexed: 01/07/2023]
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12
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A novel perspective on neuron study: damaging and promoting effects in different neurons induced by mechanical stress. Biomech Model Mechanobiol 2015; 15:1019-27. [DOI: 10.1007/s10237-015-0743-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 10/29/2015] [Indexed: 12/11/2022]
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13
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Mata D, Linn DM, Linn CL. Retinal ganglion cell neuroprotection induced by activation of alpha7 nicotinic acetylcholine receptors. Neuropharmacology 2015; 99:337-46. [PMID: 26239818 DOI: 10.1016/j.neuropharm.2015.07.036] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 07/28/2015] [Accepted: 07/29/2015] [Indexed: 10/23/2022]
Abstract
The α7nAChR agonist, PNU-282987, has previously been shown to have a neuroprotective effect against loss of retinal ganglion cells (RGCs) in an in vivo glaucoma model when the agent was injected into the vitreous chamber of adult Long Evans rat eyes. Here, we characterized the neuroprotective effect of PNU-282987 at the nerve fiber and retinal ganglion cell layer, determined that neuroprotection occurred when the agonist was applied as eye drops and verified detection of the agonist in the retina, using LC/MS/MS. To induce glaucoma-like conditions in adult Long Evans rats, hypertonic saline was injected into the episcleral veins to induce scar tissue and increase intraocular pressure. Within one month, this procedure produced significant loss of RGCs compared to untreated conditions. RGCs were quantified after immunostaining with an antibody against Thy 1.1 and imaged using a confocal microscope. In dose-response studies, concentrations of PNU-282987 were applied to the animal's right eye two times each day, while the left eye acted as an internal control. Eye drops of PNU-282987 resulted in neuroprotection against RGC loss in a dose-dependent manner using concentrations between 100 μM and 2 mM PNU-282987. LC/MS/MS results demonstrated that PNU-282987 was detected in the retina when applied as eye drops, relatively small amounts of PNU-282987 were measured in blood plasma and no PNU-282987 was detected in cardiac tissue. These results support the hypothesis that eye drop application of PNU-282987 can prevent loss of RGCs associated with glaucoma, which can lead to neuroprotective treatments for diseases that involve α7nAChRs.
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Affiliation(s)
- David Mata
- Western Michigan University, Department of Biological Sciences, Kalamazoo, MI 49008, USA.
| | - David M Linn
- Grand Valley State University, Department of Biomedical Sciences, Allendale, MI 49401, USA.
| | - Cindy L Linn
- Western Michigan University, Department of Biological Sciences, Kalamazoo, MI 49008, USA.
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Retinal ganglion cell dendrite pathology and synapse loss: Implications for glaucoma. PROGRESS IN BRAIN RESEARCH 2015; 220:199-216. [PMID: 26497792 DOI: 10.1016/bs.pbr.2015.04.012] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Dendrites are exquisitely specialized cellular compartments that critically influence how neurons collect and process information. Retinal ganglion cell (RGC) dendrites receive synaptic inputs from bipolar and amacrine cells, thus allowing cell-to-cell communication and flow of visual information. In glaucoma, damage to RGC axons results in progressive neurodegeneration and vision loss. Recent data indicate that axonal injury triggers rapid structural alterations in RGC dendritic arbors, prior to manifest axonal loss, which lead to synaptic rearrangements and functional deficits. Here, we provide an update on recent work addressing the role of RGC dendritic degeneration in models of acute and chronic optic nerve damage as well as novel mechanisms that regulate RGC dendrite stability. A better understanding of how defects in RGC dendrites contribute to neurodegeneration in glaucoma might provide new insights into disease onset and progression, while informing the development of novel therapies to prevent vision loss.
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15
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Characteristic patterns of dendritic remodeling in early-stage glaucoma: evidence from genetically identified retinal ganglion cell types. J Neurosci 2015; 35:2329-43. [PMID: 25673829 DOI: 10.1523/jneurosci.1419-14.2015] [Citation(s) in RCA: 160] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Retinal ganglion cell (RGC) loss is a hallmark of glaucoma and the second leading cause of blindness worldwide. The type and timing of cellular changes leading to RGC loss in glaucoma remain incompletely understood, including whether specific RGC subtypes are preferentially impacted at early stages of this disease. Here we applied the microbead occlusion model of glaucoma to different transgenic mouse lines, each expressing green fluorescent protein in 1-2 specific RGC subtypes. Targeted filling, reconstruction, and subsequent comparison of the genetically identified RGCs in control and bead-injected eyes revealed that some subtypes undergo significant dendritic rearrangements as early as 7 d following induction of elevated intraocular pressure (IOP). By comparing specific On-type, On-Off-type and Off-type RGCs, we found that RGCs that target the majority of their dendritic arbors to the scleral half or "Off" sublamina of the inner plexiform layer (IPL) undergo the greatest changes, whereas RGCs with the majority of their dendrites in the On sublamina did not alter their structure at this time point. Moreover, M1 intrinsically photosensitive RGCs, which functionally are On RGCs but structurally stratify their dendrites in the Off sublamina of the IPL, also underwent significant changes in dendritic structure 1 week after elevated IOP. Thus, our findings reveal that certain RGC subtypes manifest significant changes in dendritic structure after very brief exposure to elevated IOP. The observation that RGCs stratifying most of their dendrites in the Off sublamina are first to alter their structure may inform the development of new strategies to detect, monitor, and treat glaucoma in humans.
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Gidday JM, Zhang L, Chiang CW, Zhu Y. Enhanced Retinal Ganglion Cell Survival in Glaucoma by Hypoxic Postconditioning After Disease Onset. Neurotherapeutics 2015; 12:502-14. [PMID: 25549850 PMCID: PMC4404439 DOI: 10.1007/s13311-014-0330-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The neuroprotective efficacy of adaptive epigenetics, wherein beneficial gene expression changes are induced by nonharmful "conditioning" stimuli, is now well established in several acute, preclinical central nervous system injury models. Recently, in a mouse model of glaucoma, we demonstrated retinal ganglion cell (RGC) protection by repetitively "preconditioning" with hypoxia prior to disease onset, indicating an epigenetic approach may also yield benefits in chronic neurodegenerative disease. Herein, we determined whether presenting the repetitive hypoxic stimulus after disease initiation [repetitive hypoxic "postconditioning" (RH-Post)] could afford similar functional and morphologic protection against glaucomatous RGC injury. Chronic elevations in intraocular pressure (IOP) were induced unilaterally in adult male C57BL/6 mice by episcleral vein ligation. Mice were randomized to an RH-Post [1 h of systemic hypoxia (11% oxygen) every other day, starting 4 days after IOP elevation] or an untreated control group. After 3 weeks of experimental glaucoma, the 21-27% reduction and 5-25% prolongation in flash visual-evoked potential amplitudes and latencies, respectively, and the 30% impairment in visual acuity were robustly improved in RH-Post-treated mice, as was the 17% loss in RGC soma number and 20% reduction in axon integrity. These protective effects were observed without RH-Post affecting IOP. The present findings demonstrate that functional and morphologic protection of RGCs can be realized by stimulating epigenetic responses during the early stages of disease, and thus constitute a new conceptual approach to glaucoma therapeutics.
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Affiliation(s)
- Jeffrey M Gidday
- Department of Neurosurgery, Washington University School of Medicine, St. Louis, MO, 63110, USA,
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17
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Dekeyster E, Aerts J, Valiente-Soriano FJ, De Groef L, Vreysen S, Salinas-Navarro M, Vidal-Sanz M, Arckens L, Moons L. Ocular hypertension results in retinotopic alterations in the visual cortex of adult mice. Curr Eye Res 2015; 40:1269-83. [PMID: 25615273 DOI: 10.3109/02713683.2014.990983] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
PURPOSE Glaucoma is a group of optic neuropathies characterized by the loss of retinal ganglion cells (RGCs). Since ocular hypertension (OHT) is a main risk factor, current therapies are predominantly based on lowering eye pressure. However, a subset of treated patients continues to lose vision. More research into pathological mechanisms underlying glaucoma is therefore warranted in order to develop novel therapeutic strategies. In this study we investigated the impact of OHT from eye to brain in mice. METHODS Monocular hypertension (mOHT) was induced in CD-1 mice by laser photocoagulation (LP) of the perilimbal and episcleral veins. The impact on the retina and its main direct target area, the superficial superior colliculus (sSC), was examined via immunostainings for Brn3a, VGluT2 and GFAP. Alterations in neuronal activity in V1 and extrastriate areas V2L and V2M were assessed using in situ hybridization for the activity reporter gene zif268. RESULTS Transient mOHT resulted in diffuse and sectorial RGC degeneration. In the sSC contralateral to the OHT eye, a decrease in VGluT2 immunopositive synaptic connections was detected one week post LP, which appeared to be retinotopically linked to the sectorial RGC degeneration patterns. In parallel, hypoactivity was discerned in contralateral retinotopic projection zones in V1 and V2. Despite complete cortical reactivation 4 weeks post LP, in the sSC no evidence for recovery of RGC synapse density was found and also the concomitant inflammation was not completely resolved. Nevertheless, sSC neurons appeared healthy upon histological inspection and subsequent analysis of cell density revealed no differences between the ipsi- and contralateral sSC. CONCLUSION In addition to RGC death, OHT induces loss of synaptic connections and neuronal activity in the visual pathway and is accompanied by an extensive immune response. Our findings stress the importance of looking beyond the eye and including the whole visual system in glaucoma research.
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Affiliation(s)
- Eline Dekeyster
- a Neural Circuit Development and Regeneration Research Group, Department of Biology, KU Leuven , Leuven , Belgium
| | - Jeroen Aerts
- b Laboratory of Neuroplasticity and Neuroproteomics, Department of Biology , KU Leuven , Leuven , Belgium and
| | | | - Lies De Groef
- a Neural Circuit Development and Regeneration Research Group, Department of Biology, KU Leuven , Leuven , Belgium
| | - Samme Vreysen
- b Laboratory of Neuroplasticity and Neuroproteomics, Department of Biology , KU Leuven , Leuven , Belgium and
| | - Manuel Salinas-Navarro
- a Neural Circuit Development and Regeneration Research Group, Department of Biology, KU Leuven , Leuven , Belgium
| | - Manuel Vidal-Sanz
- c Department of Ophthalmology , University of Murcia and IMIB-Arrixaca , Murcia , Spain
| | - Lutgarde Arckens
- b Laboratory of Neuroplasticity and Neuroproteomics, Department of Biology , KU Leuven , Leuven , Belgium and
| | - Lieve Moons
- a Neural Circuit Development and Regeneration Research Group, Department of Biology, KU Leuven , Leuven , Belgium
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18
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Gui D, Li Y, Chen X, Gao D, Yang Y, Li X. HIF‑1 signaling pathway involving iNOS, COX‑2 and caspase‑9 mediates the neuroprotection provided by erythropoietin in the retina of chronic ocular hypertension rats. Mol Med Rep 2014; 11:1490-6. [PMID: 25370745 DOI: 10.3892/mmr.2014.2859] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 08/22/2014] [Indexed: 11/05/2022] Open
Abstract
This study aimed to investigate the impacts of erythropoietin (EPO) on the electroretinogram b‑wave (ERG‑b), and on the mRNA and protein expression levels of hypoxia‑inducible factor‑1α (HIF‑1α), inducible nitric oxide synthase (iNOS), cyclooxygenase‑2 (COX‑2) and caspase‑9 in chronic ocular hypertension rats. Episcleral vein cauterization (EVC) was used to establish the chronic ocular hypertension rat model based on the intraocular pressure (IOP) value. ERG‑b and mRNA and protein expression levels of HIF‑1α, iNOS, COX‑2 and caspase‑9 in normal, EVC‑treated and EVC combined with EPO (EVC+EPO)‑treated rats were measured by electroretinography, RT‑PCR and western blotting, respectively. Moreover, the correlations of HIF‑1α with IOP, ERG‑b, iNOS, COX‑2 and caspase‑9 were evaluated. The mRNA and protein expression levels of HIF‑1α, iNOS, COX‑2 and caspase‑9 in EVC‑treated rats were increased significantly compared with normal rats. The peak expression levels of HIF‑1α, iNOS, COX‑2 and caspase‑9 were respectively obtained 7, 7, 7 and 14 days postoperatively. Compared with EVC‑treated rats, EPO administration weakened the mRNA and protein expression levels of HIF‑1α, iNOS, COX‑2 and caspase‑9. The mRNA expression level of HIF‑1α demonstrated a significant positive correlation with IOP and ERG‑b. HIF‑1α was positively correlated with iNOS, COX‑2 and caspase‑9 at the mRNA and protein levels. The protective effect of EPO on the retina of chronic ocular hypertension rats may be mediated by the HIF‑1 signaling pathway involving iNOS, COX‑2 and caspase‑9.
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Affiliation(s)
- Dongmei Gui
- Department of Ophthalmology, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, P.R. China
| | - Yanfeng Li
- Department of Neurosurgery, The People's Hospital of Liaoning Province, Shenyang, Liaoning 110025, P.R. China
| | - Xiaolong Chen
- Department of Ophthalmology, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, P.R. China
| | - Dianwen Gao
- Department of Ophthalmology, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, P.R. China
| | - Yang Yang
- Department of Ophthalmology, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, P.R. China
| | - Xun Li
- Department of Ophthalmology, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, P.R. China
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19
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Chong RS, Martin KR. Retinal ganglion cell dendrites and glaucoma: a case of missing the wood for the trees? EXPERT REVIEW OF OPHTHALMOLOGY 2014. [DOI: 10.1586/17469899.2014.917048] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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20
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Differential progression of structural and functional alterations in distinct retinal ganglion cell types in a mouse model of glaucoma. J Neurosci 2013; 33:17444-57. [PMID: 24174678 DOI: 10.1523/jneurosci.5461-12.2013] [Citation(s) in RCA: 183] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Intraocular pressure (IOP) elevation is a principal risk factor for glaucoma. Using a microbead injection technique to chronically raise IOP for 15 or 30 d in mice, we identified the early changes in visual response properties of different types of retinal ganglion cells (RGCs) and correlated these changes with neuronal morphology before cell death. Microbead-injected eyes showed reduced optokinetic tracking as well as cell death. In such eyes, multielectrode array recordings revealed that four RGC types show diverse alterations in their light responses upon IOP elevation. OFF-transient RGCs exhibited a more rapid decline in both structural and functional organizations compared with other RGCs. In contrast, although the light-evoked responses of OFF-sustained RGCs were perturbed, the dendritic arbor of this cell type remained intact. ON-transient and ON-sustained RGCs had normal functional receptive field sizes but their spontaneous and light-evoked firing rates were reduced. ON- and OFF-sustained RGCs lost excitatory synapses across an otherwise structurally normal dendritic arbor. Together, our observations indicate that there are changes in spontaneous activity and light-evoked responses in RGCs before detectable dendritic loss. However, when dendrites retract, we found corresponding changes in receptive field center size. Importantly, the effects of IOP elevation are not uniformly manifested in the structure and function of diverse RGC populations, nor are distinct RGC types perturbed within the same time-frame by such a challenge.
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21
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Shimada Y, Hirano M, Nishimura Y, Tanaka T. A high-throughput fluorescence-based assay system for appetite-regulating gene and drug screening. PLoS One 2012; 7:e52549. [PMID: 23300705 PMCID: PMC3530442 DOI: 10.1371/journal.pone.0052549] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Accepted: 11/20/2012] [Indexed: 12/13/2022] Open
Abstract
The increasing number of people suffering from metabolic syndrome and obesity is becoming a serious problem not only in developed countries, but also in developing countries. However, there are few agents currently approved for the treatment of obesity. Those that are available are mainly appetite suppressants and gastrointestinal fat blockers. We have developed a simple and rapid method for the measurement of the feeding volume of Danio rerio (zebrafish). This assay can be used to screen appetite suppressants and enhancers. In this study, zebrafish were fed viable paramecia that were fluorescently-labeled, and feeding volume was measured using a 96-well microplate reader. Gene expression analysis of brain-derived neurotrophic factor (bdnf), knockdown of appetite-regulating genes (neuropeptide Y, preproinsulin, melanocortin 4 receptor, agouti related protein, and cannabinoid receptor 1), and the administration of clinical appetite suppressants (fluoxetine, sibutramine, mazindol, phentermine, and rimonabant) revealed the similarity among mechanisms regulating appetite in zebrafish and mammals. In combination with behavioral analysis, we were able to evaluate adverse effects on locomotor activities from gene knockdown and chemical treatments. In conclusion, we have developed an assay that uses zebrafish, which can be applied to high-throughput screening and target gene discovery for appetite suppressants and enhancers.
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Affiliation(s)
- Yasuhito Shimada
- Department of Molecular and Cellular Pharmacology, Pharmacogenomics and Pharmacoinformatics, Mie University Graduate School of Medicine, Tsu, Mie, Japan
- Mie University Medical Zebrafish Research Center, Tsu, Mie, Japan
- Department of Bioinformatics, Mie University Life Science Research Center, Tsu, Mie, Japan
- Department of Omics Medicine, Mie University Industrial Technology Innovation Institute, Tsu, Mie, Japan
| | - Minoru Hirano
- Department of Molecular and Cellular Pharmacology, Pharmacogenomics and Pharmacoinformatics, Mie University Graduate School of Medicine, Tsu, Mie, Japan
| | - Yuhei Nishimura
- Department of Molecular and Cellular Pharmacology, Pharmacogenomics and Pharmacoinformatics, Mie University Graduate School of Medicine, Tsu, Mie, Japan
- Mie University Medical Zebrafish Research Center, Tsu, Mie, Japan
- Department of Bioinformatics, Mie University Life Science Research Center, Tsu, Mie, Japan
- Department of Omics Medicine, Mie University Industrial Technology Innovation Institute, Tsu, Mie, Japan
| | - Toshio Tanaka
- Department of Molecular and Cellular Pharmacology, Pharmacogenomics and Pharmacoinformatics, Mie University Graduate School of Medicine, Tsu, Mie, Japan
- Mie University Medical Zebrafish Research Center, Tsu, Mie, Japan
- Department of Bioinformatics, Mie University Life Science Research Center, Tsu, Mie, Japan
- Department of Omics Medicine, Mie University Industrial Technology Innovation Institute, Tsu, Mie, Japan
- * E-mail:
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Kalesnykas G, Oglesby EN, Zack DJ, Cone FE, Steinhart MR, Tian J, Pease ME, Quigley HA. Retinal ganglion cell morphology after optic nerve crush and experimental glaucoma. Invest Ophthalmol Vis Sci 2012; 53:3847-57. [PMID: 22589442 DOI: 10.1167/iovs.12-9712] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
PURPOSE To study sequential changes in retinal ganglion cell (RGC) morphology in mice after optic nerve crush and after induction of experimental glaucoma. METHODS Nerve crush or experimental glaucoma was induced in mice that selectively express yellow fluorescent protein (YFP) in RGCs. Mice were euthanized 1, 4, and 9 days after crush and 1, 3, and 6 weeks after induction of glaucoma by bead injection. All YFP-RGCs were identified in retinal whole mounts. Then confocal images of randomly selected RGCs were quantified for somal fluorescence brightness, soma size, neurite outgrowth, and dendritic complexity (Sholl analysis). RESULTS By 9 days after crush, 98% of RGC axons died and YFP-RGCs decreased by 64%. After 6 weeks of glaucoma, 31% of axons died, but there was no loss of YFP-RGC bodies. All crush retinas combined had significant decreases in neurite outgrowth parameters (P ≤ 0.036, generalized estimating equation [GEE] model) and dendritic complexity was lower than controls (P = 0.017, GEE model). There was no change in RGC soma area after crush. In combined glaucoma data, the RGC soma area was larger than control (P = 0.04, GEE model). At 3 weeks, glaucoma RGCs had significantly larger values for dendritic structure and complexity than controls (P = 0.044, GEE model), but no statistical difference was found at 6 weeks. CONCLUSIONS After nerve crush, RGCs and axons died rapidly, and dendritic structure decreased moderately in remaining RGCs. Glaucoma caused an increase in RGC dendrite structure and soma size at 3 weeks.
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Affiliation(s)
- Giedrius Kalesnykas
- Department of Ophthalmology, Institute of Clinical Medicine, School of Medicine, University of Eastern Finland, Kuopio, Finland
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Changes in the modulation of retinocollicular transmission through group III mGluRs long after an increase in intraocular pressure in a rat model of glaucoma. Vis Neurosci 2012; 29:237-46. [DOI: 10.1017/s0952523812000193] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
AbstractMetabotropic glutamate receptors (mGluRs) have been shown to be involved in the modulation of retinocollicular neurotransmission. In glaucoma, retinal ganglion cells (RGCs) degenerate, which may have an implication on this transmission as the superior colliculus is their major central target in the much-used rodent models of the disease. We have investigated this using an in vitro slice preparation of the superior colliculus by eliciting field excitatory postsynaptic potentials (fEPSPs) through optic tract stimulation in a rat ocular hypertension model of glaucoma. Application of the group III mGluR agonist L-AP4 reduced the peak amplitude of the fEPSP in superior colliculus slices through presynaptic mechanisms as previously shown in our lab. At 3 and 16 weeks after surgery, there were no significant differences in the effect of L-AP4 on fEPSP peak amplitude in the superior colliculus slices receiving input from the glaucomatous eyes [elevated intraocular pressure (IOP)] compared to those with input from the unoperated eyes (normal IOP). However, at 32 weeks, the fEPSP peak amplitude was reduced to a significantly greater degree during L-AP4 application in the elevated IOP slices compared to normal IOP slices. At all time points, there were no significant changes in the baseline amplitudes of fEPSPs or the stimulus intensities required to evoke fEPSPs. These results suggest that the modulation of synaptic transmission through group III mGluRs on RGC terminals to the superior colliculus is changed at later stages due to RGC degeneration through IOP elevation. These changes may be compensatory changes possibly through plasticity in the RGC terminals of surviving cells, which may be due to increases in the numbers of group III mGluRs. This result may have implications on further treatment studies carried out using these models of glaucoma as changes in the central visual system may need to be considered along with the retinal changes that occur.
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Lee JH, Shin JM, Shin YJ, Chun MH, Oh SJ. Immunochemical changes of calbindin, calretinin and SMI32 in ischemic retinas induced by increase of intraocular pressure and by middle cerebral artery occlusion. Anat Cell Biol 2011; 44:25-34. [PMID: 21519546 PMCID: PMC3080005 DOI: 10.5115/acb.2011.44.1.25] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Revised: 02/24/2011] [Accepted: 03/02/2011] [Indexed: 12/31/2022] Open
Abstract
The reaction of neuroactive substances to ischemic conditions in the rat retina evoked by different methods was immunochemically evaluated in adult Sprague-Dawley rats. Ocular ischemic conditions were unilaterally produced by elevating intraocular pressure (EIOP) or by middle cerebral artery occlusion (MCAO). Two EF-hand calcium binding proteins, calbindin D28K (CB) and calretinin (CR), in the normal retina showed similar immunolocalization, such as the amacrine and displaced amacrine cells, the ganglion cells, and their processes, particularly CB in horizontal cells. CB immunoreactive neurons in the ganglion cell layer in both types of ischemic retinas were more reduced in number than CR neurons compared to those in a normal retina. The CB protein level in both ischemic retinas was reduced to 60-80% of normal. The CR protein level in MCAO retinas was reduced to about 80% of normal but increased gradually to the normal value, whereas that in the EIOP showed a gradual reduction and a slight recovery. SMI32 immunoreactivity, which detects a dephosphorylated epitope of neurofilaments-M and -H, appeared in the axon bundles of ganglion cells in the innermost nerve fiber layer of normal retinas. The reactivity in the nerve fiber bundles appeared to only increase slightly in EIOP retinas, whereas a moderate increase occurred in MCAO retinas. The SMI32 protein level in MCAO retinas showed a gradual increasing tendency, whereas that in the EIOP showed a slight fluctuation. Interestingly, the MCAO retinas showed additional SMI32 immunoreactivity in the cell soma of presumed ganglion cells, whereas that of EIOP appeared in the Müller proximal radial fibers. Glial fibrillary acidic protein (GFAP) immunoreactivity appeared in the astrocytes located in the nerve fiber layer of normal retinas. Additional GFAP immunoreactivity appeared in the Müller glial fibers deep in EIOP retinas and at the proximal end in MCAO retinas. These findings suggest that the neurons in the ganglion cell layer undergo degenerative changes in response to ischemia, although EIOP retinas represented a remarkable Müller glial reaction, whereas MCAO retinas had only a small-scaled axonal transport disturbance.
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Affiliation(s)
- Jong-Hyun Lee
- Department of Anatomy, College of Medicine, The Catholic University of Korea, Seoul, Korea
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Ahmed F, MacArthur L, De Bernardi MA, Mocchetti I. Retrograde and anterograde transport of HIV protein gp120 in the nervous system. Brain Behav Immun 2009; 23:355-64. [PMID: 19111924 PMCID: PMC2857724 DOI: 10.1016/j.bbi.2008.11.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2008] [Revised: 11/26/2008] [Accepted: 11/27/2008] [Indexed: 11/15/2022] Open
Abstract
Neurodegeneration and gliosis are prominent pathological features of subjects with human immunodeficiency virus (HIV) dementia complex (HAD). In these patients, neurodegeneration occurs in uninfected neurons. In addition, these patients develop sensory neuropathy despite the antiretroviral therapy. The HIV protein gp120, which mimics some of the pathological alterations seen in HAD, is retrogradely transported in rodent neurons. However, it is still unclear whether gp120 can also be transported anterogradely and whether axonal transport can occur in the peripheral nervous system (PNS). To determine whether gp120 is transported retrogradely and/or anterogradely, we injected gp120IIIB together with the retrograde tracer fluoro-ruby (FR) or the anterograde tracer 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyamine perchlorate (DiI) into the rat superior colliculi. We discovered that gp120 is retrogradely transported with FR along a direct pathway from the superior colliculus to the retina and anterogradely transported with DiI to several areas of the occipital cortex. To determine whether gp120 is also axonally transported in the peripheral nerves, gp120 and FR were injected into the sciatic nerve. No gp120 immunoreactivity was found in the sciatic nerve or dorsal root ganglia, suggesting that gp120 axonal transport does not occur in the PNS. Gp120 axonal transport may play a role in neuronal injury. Therefore, we examined apoptosis at various time points after gp120 injection. Activated caspase-3 was evident within neurons transporting gp120. These results indicate that axonal transport of gp120 might exacerbate the pathogenesis of HIV-1.
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Affiliation(s)
- Farid Ahmed
- Department of Neuroscience, Georgetown University Medical Center, Washington, D.C. 20057
| | - Linda MacArthur
- Department of Neuroscience, Georgetown University Medical Center, Washington, D.C. 20057
| | - Maria A. De Bernardi
- Microscopy Center, Johns Hopkins University Montgomery County Campus, Rockville, Maryland 20850
| | - Italo Mocchetti
- Department of Neuroscience, Georgetown University Medical Center, Washington, D.C. 20057
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27
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Sharma SC. Changes of central visual receptive fields in experimental glaucoma. PROGRESS IN BRAIN RESEARCH 2008; 173:479-91. [PMID: 18929129 DOI: 10.1016/s0079-6123(08)01133-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Retinal ganglion cell apoptotic death in experimental glaucoma is protracted over several months and it leads to the visual dysfunction. In the rat with increased intraocular pressure (IOP), the lack of visual scotoma was observed where visual field was determined electrophysiologically on the contralateral optic tectum in the early stages of the disease. Increases in the sizes of receptive fields on the periphery represented early stage of glaucomatous dysfunction. The relationship of duration and magnitude of IOP elevation had a significant correlation between percentages of receptive field sizes in the tectum. Large increases in receptive field sizes noted in the glaucomatous retinal terminal areas suggest the ability of the remaining retinal axons to compete and compensate for the loss of retinal axons. This compensatory adaptation leads to the degradation of the visual acuity and visual thresholds when measured psychophysically.
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Affiliation(s)
- S C Sharma
- Department of Ophthalmology, New York Medical College, Valhalla, NY 10595, USA.
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28
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Qin Y, Xu G, Wang W. Dendritic abnormalities in retinal ganglion cells of three-month diabetic rats. Curr Eye Res 2007; 31:967-74. [PMID: 17114122 DOI: 10.1080/02713680600987674] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
PURPOSE To determine the effect of three-month diabetes on the retinal ganglion cell (RGC) morphology and density. METHODS Experimental diabetes was induced in Sprague-Dawley rats by intraperitoneal injection of streptozotocin (STZ). Retinas from three-month diabetic and age-matched control rats were harvested, and immunohistochemistry with monoclonal anti-Thy-1 antibody was carried out for calculating RGC density. Random RGC labeling with gene gun propelled lipophilic fluorescent dye, DiI, coated particles (DiOlistic method) was done for detailed RGC classification, dendritic field, and soma size measurement. RESULTS The number of Thy1-labeled RGCs in the three-month diabetic rats was significantly reduced compared with that in the age-matched control. Obvious RGC morphology changes were observed, and the number of RGCs that could not be classified was significantly greater in the diabetic retinas. Among those well-classified RGCs, cells with enlarged dendritic fields were more frequently seen in the RGA group (401+/-86 um, n = 59, P < 0.001), but the soma sizes were unchanged from the controls (P > 0.05). For cells in the groups of RGB and RGC, no significant changes in the dendritic fields and soma sizes were found (P > 0.05). CONCLUSIONS In the three-month STZ-induced diabetic rat, retinal ganglion cell loss is associated with morphology change. The surviving RGCs in the diabetic retina, especially those in RGA group, show significant dendritic field enlargement. This plasticity of the surviving RGC dendrites may represent a compensatory response to the overall loss of RGCs in diabetes.
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Affiliation(s)
- Yaowu Qin
- EENT Hospital, Eye Institute, Fudan University, Shanghai, China
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29
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King WM, Sarup V, Sauvé Y, Moreland CM, Carpenter DO, Sharma SC. Expansion of visual receptive fields in experimental glaucoma. Vis Neurosci 2006; 23:137-42. [PMID: 16597357 DOI: 10.1017/s0952523806231122] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2005] [Accepted: 10/19/2005] [Indexed: 11/06/2022]
Abstract
Glaucoma is a major cause of blindness and is characterized by death of retinal ganglion cells. In a rat model of glaucoma in which intraocular pressure is raised by cautery of episcleral veins, the somata and dendritic arbors of surviving retinal ganglion cells expand. To assess physiological consequences of this change, we have measured visual receptive-field size in a primary retinal target, the superior colliculus. Using multiunit recording, receptive-field sizes were measured for glaucomatous eyes and compared to both those measured for contralateral control eyes and to homolateral eyes of unoperated animals. Episcleral vein occlusion increased intraocular pressure. This was accompanied by a significant increase in receptive-field size across the superior colliculus. The expansion of receptive fields was proportional to both degree and duration of the increase of intraocular pressure. We suggest that this increase in the size of receptive fields of glaucomatous eyes may be related to the increase in the size of dendritic arbors of the surviving ganglion cells in retina.
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Affiliation(s)
- Wayne Michael King
- Departments of Ophthalmology and Cell Biology and Anatomy, New York Medical College, Valhalla, New York 10595, USA
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30
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Urcola JH, Hernández M, Vecino E. Three experimental glaucoma models in rats: comparison of the effects of intraocular pressure elevation on retinal ganglion cell size and death. Exp Eye Res 2006; 83:429-37. [PMID: 16682027 DOI: 10.1016/j.exer.2006.01.025] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2005] [Revised: 01/12/2006] [Accepted: 01/17/2006] [Indexed: 02/06/2023]
Abstract
Glaucoma is a chronic and progressive optic nerve neuropathy involving the death of retinal ganglion cells (RGCs). Elevated intraocular pressure (IOP) is considered to be the major risk factor associated with the development of this neuropathy. The objective of the present study was to compare the effects on RGC survival of three different experimental methods to induce chronic elevation of IOP in rats. These methods were: (i) injections of latex microspheres into the eye anterior chamber; (ii) injections into the anterior chamber of a mixture of microspheres plus hydroxypropylmethylcellulose (HPM) and (iii) cauterization of three episcleral veins. The IOP of right (control) and left (glaucomatous) eyes was measured with an applanation tonometer in awake animals. Thirteen to 30 weeks later, RGCs were retrogradely labeled with 3% fluorogold. Subsequently, we analyzed the density of RGCs, as well as the major axis length and area of RGC soma resulting from the application of each method. A significant increase in IOP was found following application of each of the three methods. Cell death was evident in the glaucomatous eyes as compared to controls. However, no statistical differences were found between the extent of cell death associated with each of the three methods. IOP increase also induced a significant increase in the size of the soma of the remaining RGCs. In conclusion, the three methods used to increase IOP induce a similar degree of RGC death. Moreover, the extent of cell death was similar when the retinas were maintained under conditions of elevated IOP for 24 weeks in comparison to 13 weeks.
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Affiliation(s)
- J Haritz Urcola
- Mendaro Hospital Department of Ophthalmology, University of the Basque Country, E-48940 Leioa, Vizcaya, Spain
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31
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Johnson EC, Cepurna WO, Jia L, Morrison JC. The use of cyclodialysis to limit exposure to elevated intraocular pressure in rat glaucoma models. Exp Eye Res 2006; 83:51-60. [PMID: 16530758 DOI: 10.1016/j.exer.2005.10.032] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2005] [Revised: 08/02/2005] [Accepted: 10/27/2005] [Indexed: 11/20/2022]
Abstract
Elevated intraocular pressure (IOP) is the most common risk factor for glaucoma and pressure control is the goal of current clinical glaucoma therapy. Yet, recent clinical studies have documented that, even after therapeutic lowering of IOP, glaucomatous visual field loss can progress in many patients. Experimental elevation of IOP in the rat is commonly used to model human glaucomatous injury. However, there currently is no rodent model for the clinical situation of glaucomatous progression in eyes with apparently controlled IOP. The purpose of this study was to evaluate the ability of surgical cyclodialysis to produce both prolonged, non-injurious reduction of IOP in rat eyes and to stably normalize IOP in eyes with experimental pressure elevation. To perform cyclodialysis, a blunted spatula was fashioned from a hypodermic needle and used to separate a portion of the ciliary body from the sclera, opening a channel into the suprachoroidal space to allow aqueous outflow. Experimental IOP elevation was produced in rats by unilateral injection of hypertonic saline. Cyclodialysis in normal eyes resulted in an average 40 +/- 4% reduction in IOP, without marked hypotony. IOP lowering could be sustained for at least 6 months. The risk of retinal or optic nerve injury following a single cyclodialysis procedure was minimal as evidenced by unaltered levels of four injury-responsive retinal mRNAs and by normal optic nerve morphology. Cyclodialysis in eyes with experimental IOP elevation resulted in IOP normalization that was sustained for durations of 7 and 21 days in 88% and 53% of eyes, respectively. In addition, in eyes with the same cumulative dose of elevated IOP prior to the procedure, successful IOP normalization by cyclodialysis resulted in significantly less optic nerve injury than that seen in eyes in which IOP control was ineffective (p = 0.03). These studies show that cyclodialysis provides a simple, non-injurious method to reduce experimentally elevated IOP in rats that can be used to model the clinical situation of eyes previously damaged by pressure. This tool offers new opportunities for identifying and studying the molecular processes associated with glaucomatous progression and for testing potential neuroprotective therapies in a clinically relevant situation.
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Affiliation(s)
- Elaine C Johnson
- Kenneth C. Swan Ocular Neurobiology Laboratory, Casey Eye Institute, Oregon Health Sciences University, 3375 S.W. Terwilliger Blvd, Portland, OR 97201, USA.
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Morgan JE, Datta AV, Erichsen JT, Albon J, Boulton ME. Retinal ganglion cell remodelling in experimental glaucoma. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2006; 572:397-402. [PMID: 17249602 DOI: 10.1007/0-387-32442-9_56] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Affiliation(s)
- James E Morgan
- School of Optometry and Vision Sciences, Redwood Building, King Edward VII Ave, Cathays Park, Cardiff CF 10 3NB, Wales, UK
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33
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Ruiz-Ederra J, Verkman AS. Mouse model of sustained elevation in intraocular pressure produced by episcleral vein occlusion. Exp Eye Res 2005; 82:879-84. [PMID: 16310189 DOI: 10.1016/j.exer.2005.10.019] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2005] [Revised: 09/30/2005] [Accepted: 10/11/2005] [Indexed: 11/30/2022]
Abstract
We have developed an inducible mouse model of glaucoma based on episcleral vein cauterization (EVC). Intraocular pressure (IOP) elevation in adult mice was produced by cauterizing three episcleral veins. Serial IOP measurements were done by induction-impact tonometry. IOP was significantly elevated by 104+/-20% in 20 out of 23 mice (87%) within the first day after EVC, and remained elevated for 4 weeks, with mean IOP 94% higher in EVC-treated vs. contralateral control eyes. Aqueous outflow blockade was verified from the IOP response to pulsed fluid infusions into the anterior chamber. Retinal ganglion cell (RGC) loss, determined by retrograde labelling using Fluoro-Gold applied to the superior colliculous, was approximately 20% at 2 weeks after EVC. We conclude that episcleral vein occlusion in mice produces significant and sustained elevation in IOP associated with increased outflow resistance and RGC loss, and thus may be useful to model glaucoma in genetically modified and drug-treated mice.
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Affiliation(s)
- Javier Ruiz-Ederra
- Department of Medicine and Physiology, Cardiovascular Research Institute, University of California, San Francisco, CA 94143-0521, USA
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Abstract
Glaucoma is a major cause of irreversible blindness in the world. The prevalence of glaucomatous loss in vision will continue to grow as our populations age. Ocular hypertension is a major risk factor for the development of glaucoma and current glaucoma therapy is directed at lowering intraocular pressure. Several new ocular hypotensive agents have been introduced in the past several years providing a variety of treatment options. In addition, various classes of neuroprotective agents demonstrating activity in a wide variety of animal models have been proposed as potential new glaucoma therapeutics. Although these approaches will slow the progression of vision loss, they do not directly intervene in the disease process(es). Advances have been made attempting to understand the pathogenic pathways involved in glaucomatous damage to the eye and in methods to clinically measure glaucoma damage. An increased understanding of the pathophysiology of glaucoma will lead to the development of new therapeutic agents that intervene and perhaps even reverse glaucomatous damage to the eye. There also is a need to develop new methods to clinically measure glaucoma damage because, currently, considerable damage occurs before glaucoma is diagnosed and glaucoma remains underdiagnosed in the general population.
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Affiliation(s)
- Abbot F Clark
- Glaucoma Research R2-41, Alcon Research Ltd, 6201 South Freeway, Fort Worth, Texas 76134, USA.
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35
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Qin Q, Patil K, Sharma SC. The role of Bax-inhibiting peptide in retinal ganglion cell apoptosis after optic nerve transection. Neurosci Lett 2004; 372:17-21. [PMID: 15531080 DOI: 10.1016/j.neulet.2004.08.075] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2004] [Revised: 08/30/2004] [Accepted: 08/31/2004] [Indexed: 01/30/2023]
Abstract
Bax, a pro-apoptotic member of Bcl-2 family proteins, plays a central role in mitochondria-dependent apoptosis. Bax normally resides in the cytosol in a quiescent state. Bax-inhibiting peptide (BIP) is a membrane permeable peptide comprised of five amino acids designed from the Bax-binding domain of Ku70 [M. Sawada, P. Hayes, S. Matsuyama, Cytoprotective membrane-permeable peptides designed from the Bax-binding domain of Ku70, Nat. Cell Biol. 5 (2003) 352-357]. It inhibits Bax-mediated translocation of cytochrome c and suppresses mitochondria-dependent apoptosis. BIP was used in order to elucidate its role in preventing retinal ganglion cell (RGC) death from apoptosis after optic nerve transection (ONT) in adult Wistar rats. RGC survival was significantly higher in animals with intravitreal injection of BIP, when compared with control animals. These findings suggest that BIP prevented RGC apoptosis after ONT prompting the suggestion that Bax plays a central role in RGC apoptosis after ONT.
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Affiliation(s)
- Qiong Qin
- Department of Ophthalmology, Cell Biology and Anatomy, New York Medical College, Valhalla, NY 10595, USA
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36
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Schwartz M. Optic nerve crush: protection and regeneration. Brain Res Bull 2004; 62:467-71. [PMID: 15036559 DOI: 10.1016/s0361-9230(03)00076-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2003] [Accepted: 02/17/2003] [Indexed: 10/26/2022]
Abstract
In neurodegenerative disorders, as well as in acute central nervous system (CNS) injuries, the initial impairment triggers a cascade of destructive events, collectively termed secondary degeneration, which eventually cause much more extensive damage. To investigate the process of secondary degeneration and ways to prevent it, we designed a well-calibrated model of optic nerve crush injury. Until recently, the main purpose of the immune system was thought to be protection of the body against alien pathogens. Since mechanical or biochemical insults do not involve exogenous pathogens, recruitment of the adaptive immune system was not considered relevant in such cases. We recently demonstrated, however, that a T-cell-mediated immune response directed against self-antigens residing in the site of damage can be beneficial for the injured optic nerve or spinal cord. This protective autoimmune response was found to be spontaneously evoked in some individuals, but not strongly enough to significantly affect recovery. Our aim was to boost this protective response in those individuals capable of spontaneously manifesting it, and to induce it in those incapable of manifesting it spontaneously. Optimal functional recovery requires the application of a proper combination of neuroprotection and neuroregeneration.
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Affiliation(s)
- Michal Schwartz
- Department of Neurobiology, The Weizmann Institute of Science, 76100 Rehovot, Israel.
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37
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Rudzinski M, Wong TP, Saragovi HU. Changes in retinal expression of neurotrophins and neurotrophin receptors induced by ocular hypertension. ACTA ACUST UNITED AC 2004; 58:341-54. [PMID: 14750147 DOI: 10.1002/neu.10293] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Open angle glaucoma is defined as a progressive and time-dependent death of retinal ganglion cells concomitant with high intraocular pressure, leading to loss of visual field. Because neurotrophins are a family of growth factors that support neuronal survival, we hypothesized that quantitative and qualitative changes in neurotrophins or their receptors may take place early in ocular hypertension, preceding extensive cell death and clinical features of glaucoma. We present molecular, biochemical, and phenotypic evidence that significant neurotrophic changes occur in retina, which correlate temporally with retinal ganglion cell death. After 7 days of ocular hypertension there is a transient up-regulation of retinal NGF, while its receptor TrkA is up-regulated in a sustained fashion in retinal neurons. After 28 days of ocular hypertension there is sustained up-regulation of retinal BDNF, but its receptor TrkB remains unchanged. Throughout, NT-3 levels remain unchanged but there is an early and sustained increase of its receptor TrkC in Müller cells but not in retinal ganglion cells. These newly synthesized glial TrkC receptors are truncated, kinase-dead isoforms. Expression of retinal p75 also increases late at day 28. Asymmetric up-regulation of neurotrophins and neurotrophin receptors may preclude efficient neurotrophic rescue of RGCs from apoptosis. A possible rationale for therapeutic intervention with Trk receptor agonists and p75 receptor antagonists is proposed.
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MESH Headings
- Animals
- Brain-Derived Neurotrophic Factor/genetics
- Brain-Derived Neurotrophic Factor/metabolism
- Carrier Proteins/genetics
- Carrier Proteins/metabolism
- Disease Models, Animal
- Disease Progression
- Glaucoma, Open-Angle/metabolism
- Glaucoma, Open-Angle/pathology
- Glaucoma, Open-Angle/physiopathology
- Glial Fibrillary Acidic Protein/metabolism
- Immunohistochemistry
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Nerve Degeneration/metabolism
- Nerve Degeneration/pathology
- Nerve Degeneration/physiopathology
- Nerve Growth Factor/genetics
- Nerve Growth Factor/metabolism
- Nerve Growth Factors/genetics
- Nerve Growth Factors/metabolism
- Neurotrophin 3/genetics
- Neurotrophin 3/metabolism
- Ocular Hypertension/metabolism
- Ocular Hypertension/pathology
- Ocular Hypertension/physiopathology
- RNA, Messenger/metabolism
- Rats
- Rats, Wistar
- Receptor, Nerve Growth Factor
- Receptor, trkA
- Receptor, trkB/genetics
- Receptor, trkB/metabolism
- Receptor, trkC/genetics
- Receptor, trkC/metabolism
- Receptors, Nerve Growth Factor/genetics
- Receptors, Nerve Growth Factor/metabolism
- Retina/metabolism
- Retina/pathology
- Retinal Ganglion Cells/metabolism
- Retinal Ganglion Cells/pathology
- Up-Regulation/physiology
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Affiliation(s)
- Marcelo Rudzinski
- Pharmacology and Therapeutics, McGill University, Montréal, QC, Canada
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38
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Abstract
The most common optic neuropathy is glaucomatous optic neuropathy, distinguished by a distinctive and progressive excavation of the optic nerve head without significant pallor of the remaining neuroretinal rim. Neuroprotection is a novel strategy for treating disorders that affect the nervous system by preventing death of neurons. In glaucomatous optic neuropathy, the neurons that die are retinal ganglion cells. This article reviews the recent basic science relevant to neuroprotection, particularly with respect to retinal ganglion cell death in glaucomatous and other optic neuropathies.
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Affiliation(s)
- Francine B Wein
- Department of Ophthalmology, McGill University Health Center, Montreal, Canada
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39
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Goldblum D, Mittag T. Prospects for relevant glaucoma models with retinal ganglion cell damage in the rodent eye. Vision Res 2002; 42:471-8. [PMID: 11853763 DOI: 10.1016/s0042-6989(01)00194-8] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Retinal ganglion cell (RGC) death is the end result of practically all diseases of the optic nerve, including glaucomatous optic neuropathy. Understanding the factors determining susceptibility of the retina or the optic nerve to glaucomatous damage, and the means to prevent it, requires good animal models. Here we review the different, current models in rodents that have been used to study RGC damage, discuss their value, and their adequacy as models for human glaucoma.
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Affiliation(s)
- David Goldblum
- Department of Ophthalmology, Mount Sinai School of Medicine, New York, USA.
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