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Bou Ghanem GO, Wareham LK, Calkins DJ. Addressing neurodegeneration in glaucoma: Mechanisms, challenges, and treatments. Prog Retin Eye Res 2024; 100:101261. [PMID: 38527623 DOI: 10.1016/j.preteyeres.2024.101261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 03/15/2024] [Accepted: 03/19/2024] [Indexed: 03/27/2024]
Abstract
Glaucoma is the leading cause of irreversible blindness globally. The disease causes vision loss due to neurodegeneration of the retinal ganglion cell (RGC) projection to the brain through the optic nerve. Glaucoma is associated with sensitivity to intraocular pressure (IOP). Thus, mainstay treatments seek to manage IOP, though many patients continue to lose vision. To address neurodegeneration directly, numerous preclinical studies seek to develop protective or reparative therapies that act independently of IOP. These include growth factors, compounds targeting metabolism, anti-inflammatory and antioxidant agents, and neuromodulators. Despite success in experimental models, many of these approaches fail to translate into clinical benefits. Several factors contribute to this challenge. Firstly, the anatomic structure of the optic nerve head differs between rodents, nonhuman primates, and humans. Additionally, animal models do not replicate the complex glaucoma pathophysiology in humans. Therefore, to enhance the success of translating these findings, we propose two approaches. First, thorough evaluation of experimental targets in multiple animal models, including nonhuman primates, should precede clinical trials. Second, we advocate for combination therapy, which involves using multiple agents simultaneously, especially in the early and potentially reversible stages of the disease. These strategies aim to increase the chances of successful neuroprotective treatment for glaucoma.
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Affiliation(s)
- Ghazi O Bou Ghanem
- Vanderbilt Eye Institute, Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, Nashville, TN, USA.
| | - Lauren K Wareham
- Vanderbilt Eye Institute, Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, Nashville, TN, USA.
| | - David J Calkins
- Vanderbilt Eye Institute, Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, Nashville, TN, USA.
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Biarnés M, Ventura-Abreu N, Rodríguez-Una I, Franquesa-Garcia F, Batlle-Ferrando S, Carrión-Donderis MT, Castro-Domínguez R, Millá E, Muniesa MJ, Pazos M. Classifying glaucoma exclusively with OCT: comparison of three clustering algorithms derived from machine learning. Eye (Lond) 2024; 38:841-846. [PMID: 37857716 DOI: 10.1038/s41433-023-02785-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 09/12/2023] [Accepted: 10/02/2023] [Indexed: 10/21/2023] Open
Abstract
BACKGROUND/AIMS To objectively classify eyes as either healthy or glaucoma based exclusively on data provided by peripapillary retinal nerve fiber layer (pRNFL) and ganglion cell-inner plexiform (GCIPL) measurements derived from spectral-domain optical coherence tomography (SD-OCT) using machine learning algorithms. METHODS Three clustering methods (k-means, hierarchical cluster analysis -HCA- and model-based clustering-MBC-) were used separately to classify a training sample of 109 eyes as either healthy or glaucomatous using solely 13 SD-OCT parameters: pRNFL average and sector thicknesses and GCIPL average and minimum values together with the six macular wedge-shaped regions. Then, the best-performing algorithm was applied to an independent test sample of 102 eyes to derive close estimates of its actual performance (external validation). RESULTS In the training sample, accuracy was 91.7% for MBC, 81.7% for k-means and 78.9% for HCA (p value = 0.02). The best MBC model was that in which subgroups were allowed to have variable volume and shape and equal orientation. The MBC algorithm in the independent test sample correctly classified 98 out of 102 cases for an overall accuracy of 96.1% (95% CI, 92.3-99.8%), with a sensitivity of 94.3 and 100% specificity. The accuracy for pRNFL was 92.2% (95% CI, 86.9-97.4%) and for GCIPL 98.0% (95% CI, 95.3-100%). CONCLUSIONS Clustering algorithms in general (and MBC in particular) seem promising methods to help discriminate between healthy and glaucomatous eyes using exclusively SD-OCT-derived parameters. Understanding the relative merits of one method over others may also provide insights into the nature of the disease.
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Affiliation(s)
- Marc Biarnés
- Oftalmologia Mèdica i Quirúrgica (OMIQ) Research, Sant Cugat del Vallès, Spain
- Institut de la Màcula (Hospital Quirón-Teknon), Barcelona, Spain
| | - Néstor Ventura-Abreu
- Institute of Ophthalmology. Hospital Clínic Barcelona, Barcelona, Spain
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
- Hospital Sagrat Cor, Barcelona, Spain
| | - Ignacio Rodríguez-Una
- Instituto Oftalmológico Fernández-Vega. Fundación de Investigación Oftalmológica, University of Oviedo, Oviedo, Spain
| | | | | | | | | | - Elena Millá
- Institute of Ophthalmology. Hospital Clínic Barcelona, Barcelona, Spain
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - María Jesús Muniesa
- Institute of Ophthalmology. Hospital Clínic Barcelona, Barcelona, Spain
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Marta Pazos
- Institute of Ophthalmology. Hospital Clínic Barcelona, Barcelona, Spain.
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.
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3
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Ho K, Bodi NE, Sharma TP. Normal-Tension Glaucoma and Potential Clinical Links to Alzheimer's Disease. J Clin Med 2024; 13:1948. [PMID: 38610712 PMCID: PMC11012506 DOI: 10.3390/jcm13071948] [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: 02/19/2024] [Revised: 03/21/2024] [Accepted: 03/25/2024] [Indexed: 04/14/2024] Open
Abstract
Glaucoma is a group of optic neuropathies and the world's leading cause of irreversible blindness. Normal-tension glaucoma (NTG) is a subtype of glaucoma that is characterized by a typical pattern of peripheral retinal loss, in which the patient's intraocular pressure (IOP) is considered within the normal range (<21 mmHg). Currently, the only targetable risk factor for glaucoma is lowering IOP, and patients with NTG continue to experience visual field loss after IOP-lowering treatments. This demonstrates the need for a better understanding of the pathogenesis of NTG and underlying mechanisms leading to neurodegeneration. Recent studies have found significant connections between NTG and cerebral manifestations, suggesting NTG as a neurodegenerative disease beyond the eye. Gaining a better understanding of NTG can potentially provide new Alzheimer's Disease diagnostics capabilities. This review identifies the epidemiology, current biomarkers, altered fluid dynamics, and cerebral and ocular manifestations to examine connections and discrepancies between the mechanisms of NTG and Alzheimer's Disease.
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Affiliation(s)
- Kathleen Ho
- Eugene and Marilyn Glick Eye Institute, Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, IN 46202, USA;
| | - Nicole E. Bodi
- Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN 46202, USA;
| | - Tasneem P. Sharma
- Eugene and Marilyn Glick Eye Institute, Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, IN 46202, USA;
- Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN 46202, USA;
- Stark Neurosciences Research Institute, Indianapolis, IN 46202, USA
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4
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Fernández-Albarral JA, Ramírez AI, de Hoz R, Matamoros JA, Salobrar-García E, Elvira-Hurtado L, López-Cuenca I, Sánchez-Puebla L, Salazar JJ, Ramírez JM. Glaucoma: from pathogenic mechanisms to retinal glial cell response to damage. Front Cell Neurosci 2024; 18:1354569. [PMID: 38333055 PMCID: PMC10850296 DOI: 10.3389/fncel.2024.1354569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 01/10/2024] [Indexed: 02/10/2024] Open
Abstract
Glaucoma is a neurodegenerative disease of the retina characterized by the irreversible loss of retinal ganglion cells (RGCs) leading to visual loss. Degeneration of RGCs and loss of their axons, as well as damage and remodeling of the lamina cribrosa are the main events in the pathogenesis of glaucoma. Different molecular pathways are involved in RGC death, which are triggered and exacerbated as a consequence of a number of risk factors such as elevated intraocular pressure (IOP), age, ocular biomechanics, or low ocular perfusion pressure. Increased IOP is one of the most important risk factors associated with this pathology and the only one for which treatment is currently available, nevertheless, on many cases the progression of the disease continues, despite IOP control. Thus, the IOP elevation is not the only trigger of glaucomatous damage, showing the evidence that other factors can induce RGCs death in this pathology, would be involved in the advance of glaucomatous neurodegeneration. The underlying mechanisms driving the neurodegenerative process in glaucoma include ischemia/hypoxia, mitochondrial dysfunction, oxidative stress and neuroinflammation. In glaucoma, like as other neurodegenerative disorders, the immune system is involved and immunoregulation is conducted mainly by glial cells, microglia, astrocytes, and Müller cells. The increase in IOP produces the activation of glial cells in the retinal tissue. Chronic activation of glial cells in glaucoma may provoke a proinflammatory state at the retinal level inducing blood retinal barrier disruption and RGCs death. The modulation of the immune response in glaucoma as well as the activation of glial cells constitute an interesting new approach in the treatment of glaucoma.
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Affiliation(s)
- Jose A. Fernández-Albarral
- Ramon Castroviejo Ophthalmological Research Institute, Complutense University of Madrid (UCM), Grupo UCM 920105, IdISSC, Madrid, Spain
| | - Ana I. Ramírez
- Ramon Castroviejo Ophthalmological Research Institute, Complutense University of Madrid (UCM), Grupo UCM 920105, IdISSC, Madrid, Spain
- Department of Immunology, Ophthalmology and ENT, Faculty of Optics and Optometry, Complutense University of Madrid, Madrid, Spain
| | - Rosa de Hoz
- Ramon Castroviejo Ophthalmological Research Institute, Complutense University of Madrid (UCM), Grupo UCM 920105, IdISSC, Madrid, Spain
- Department of Immunology, Ophthalmology and ENT, Faculty of Optics and Optometry, Complutense University of Madrid, Madrid, Spain
| | - José A. Matamoros
- Ramon Castroviejo Ophthalmological Research Institute, Complutense University of Madrid (UCM), Grupo UCM 920105, IdISSC, Madrid, Spain
- Department of Immunology, Ophthalmology and ENT, Faculty of Optics and Optometry, Complutense University of Madrid, Madrid, Spain
| | - Elena Salobrar-García
- Ramon Castroviejo Ophthalmological Research Institute, Complutense University of Madrid (UCM), Grupo UCM 920105, IdISSC, Madrid, Spain
- Department of Immunology, Ophthalmology and ENT, Faculty of Optics and Optometry, Complutense University of Madrid, Madrid, Spain
| | - Lorena Elvira-Hurtado
- Ramon Castroviejo Ophthalmological Research Institute, Complutense University of Madrid (UCM), Grupo UCM 920105, IdISSC, Madrid, Spain
| | - Inés López-Cuenca
- Ramon Castroviejo Ophthalmological Research Institute, Complutense University of Madrid (UCM), Grupo UCM 920105, IdISSC, Madrid, Spain
- Department of Immunology, Ophthalmology and ENT, Faculty of Optics and Optometry, Complutense University of Madrid, Madrid, Spain
| | - Lidia Sánchez-Puebla
- Ramon Castroviejo Ophthalmological Research Institute, Complutense University of Madrid (UCM), Grupo UCM 920105, IdISSC, Madrid, Spain
- Department of Immunology, Ophthalmology and ENT, School of Medicine, Complutense University of Madrid, Madrid, Spain
| | - Juan J. Salazar
- Ramon Castroviejo Ophthalmological Research Institute, Complutense University of Madrid (UCM), Grupo UCM 920105, IdISSC, Madrid, Spain
- Department of Immunology, Ophthalmology and ENT, Faculty of Optics and Optometry, Complutense University of Madrid, Madrid, Spain
| | - José M. Ramírez
- Ramon Castroviejo Ophthalmological Research Institute, Complutense University of Madrid (UCM), Grupo UCM 920105, IdISSC, Madrid, Spain
- Department of Immunology, Ophthalmology and ENT, School of Medicine, Complutense University of Madrid, Madrid, Spain
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Afiat BC, Zhao D, Wong VHY, Perera ND, Turner BJ, Nguyen CTO, Bui BV. Age-related deficits in retinal autophagy following intraocular pressure elevation in autophagy reporter mouse model. Neurobiol Aging 2023; 131:74-87. [PMID: 37586253 DOI: 10.1016/j.neurobiolaging.2023.07.009] [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: 01/18/2023] [Revised: 07/12/2023] [Accepted: 07/13/2023] [Indexed: 08/18/2023]
Abstract
This study quantified age-related changes to retinal autophagy using the CAG-RFP-EGFP-LC3 autophagy reporter mice and considered how aging impacts autophagic responses to acute intraocular pressure (IOP) stress. IOP was elevated to 50 mm Hg for 30 minutes in 3-month-old and 12-month-old CAG-RFP-EGFP-LC3 (n = 7 per age group) and Thy1-YFPh transgenic mice (n = 3 per age group). Compared with younger eyes, older eyes showed diminished basal autophagy in the outer retina, while the inner retina was unaffected. Autophagic flux (red:yellow puncta ratio) was elevated in the inner plexiform layer. Three days following IOP elevation, older eyes showed poorer functional recovery, most notably in ganglion cell responses compared to younger eyes (12 months old: -33.4 ± 5.3% vs. 3 months mice: -13.4 ± 4.5%). This paralleled a reduced capacity to upregulate autophagic puncta volume in the inner retina in older eyes, a response that was seen in younger eyes. Age-related decline in basal and stress-induced autophagy in the retina is associated with greater retinal ganglion cells' susceptibility to IOP elevation.
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Affiliation(s)
- Brianna C Afiat
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Da Zhao
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Vickie H Y Wong
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Nirma D Perera
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Bradley J Turner
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Christine T O Nguyen
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Bang V Bui
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Victoria, Australia.
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Camacho DK, Go CC, Chaqour B, Shindler KS, Ross AG. Emerging Gene Therapy Technologies for Retinal Ganglion Cell Neuroprotection. J Neuroophthalmol 2023; 43:330-340. [PMID: 37440418 PMCID: PMC10527513 DOI: 10.1097/wno.0000000000001955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/15/2023]
Abstract
ABSTRACT Optic neuropathies encompass a breadth of diseases that ultimately result in dysfunction and/or loss of retinal ganglion cells (RGCs). Although visual impairment from optic neuropathies is common, there is a lack of effective clinical treatments. Addressing a critical need for novel interventions, preclinical studies have been generating a growing body of evidence that identify promising new drug-based and cell-based therapies. Gene therapy is another emerging therapeutic field that offers the potential of specifically and robustly increasing long-term RGC survival in optic neuropathies. Gene therapy offers additional benefits of driving improvements following a single treatment administration, and it can be designed to target a variety of pathways that may be involved in individual optic neuropathies or across multiple etiologies. This review explores the history of gene therapy, the fundamentals of its application, and the emerging development of gene therapy technology as it relates to treatment of optic neuropathies.
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Affiliation(s)
- David K. Camacho
- F. M. Kirby Center for Molecular Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Cammille C. Go
- F. M. Kirby Center for Molecular Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Brahim Chaqour
- F. M. Kirby Center for Molecular Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Kenneth S. Shindler
- F. M. Kirby Center for Molecular Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
- Departments of Ophthalmology and Neurology, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Ahmara G. Ross
- F. M. Kirby Center for Molecular Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
- Departments of Ophthalmology and Neurology, University of Pennsylvania, Philadelphia, Pennsylvania, United States
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Bastola T, Perkins GA, Kim KY, Choi S, Kwon JW, Shen Z, Strack S, Ju WK. Role of A-Kinase Anchoring Protein 1 in Retinal Ganglion Cells: Neurodegeneration and Neuroprotection. Cells 2023; 12:1539. [PMID: 37296658 PMCID: PMC10252895 DOI: 10.3390/cells12111539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 05/21/2023] [Accepted: 06/01/2023] [Indexed: 06/12/2023] Open
Abstract
A-Kinase anchoring protein 1 (AKAP1) is a multifunctional mitochondrial scaffold protein that regulates mitochondrial dynamics, bioenergetics, and calcium homeostasis by anchoring several proteins, including protein kinase A, to the outer mitochondrial membrane. Glaucoma is a complex, multifactorial disease characterized by a slow and progressive degeneration of the optic nerve and retinal ganglion cells (RGCs), ultimately resulting in vision loss. Impairment of the mitochondrial network and function is linked to glaucomatous neurodegeneration. Loss of AKAP1 induces dynamin-related protein 1 dephosphorylation-mediated mitochondrial fragmentation and loss of RGCs. Elevated intraocular pressure triggers a significant reduction in AKAP1 protein expression in the glaucomatous retina. Amplification of AKAP1 expression protects RGCs from oxidative stress. Hence, modulation of AKAP1 could be considered a potential therapeutic target for neuroprotective intervention in glaucoma and other mitochondria-associated optic neuropathies. This review covers the current research on the role of AKAP1 in the maintenance of mitochondrial dynamics, bioenergetics, and mitophagy in RGCs and provides a scientific basis to identify and develop new therapeutic strategies that could protect RGCs and their axons in glaucoma.
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Affiliation(s)
- Tonking Bastola
- Hamilton Glaucoma Center and Shiley Eye Institute, The Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA 92093, USA; (T.B.); (S.C.); (J.-W.K.); (Z.S.)
| | - Guy A. Perkins
- National Center for Microscopy and Imaging Research, Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, USA; (G.A.P.); (K.-Y.K.)
| | - Keun-Young Kim
- National Center for Microscopy and Imaging Research, Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, USA; (G.A.P.); (K.-Y.K.)
| | - Seunghwan Choi
- Hamilton Glaucoma Center and Shiley Eye Institute, The Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA 92093, USA; (T.B.); (S.C.); (J.-W.K.); (Z.S.)
| | - Jin-Woo Kwon
- Hamilton Glaucoma Center and Shiley Eye Institute, The Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA 92093, USA; (T.B.); (S.C.); (J.-W.K.); (Z.S.)
- Department of Ophthalmology and Visual Science, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea
- Department of Ophthalmology and Visual Science, St. Vincent’s Hospital, Jungbu-daero 93, Paldal-gu, Suwon 16247, Republic of Korea
| | - Ziyao Shen
- Hamilton Glaucoma Center and Shiley Eye Institute, The Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA 92093, USA; (T.B.); (S.C.); (J.-W.K.); (Z.S.)
| | - Stefan Strack
- Department of Pharmacology, Iowa Neuroscience Institute, University of Iowa, Iowa City, IA 52242, USA;
| | - Won-Kyu Ju
- Hamilton Glaucoma Center and Shiley Eye Institute, The Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA 92093, USA; (T.B.); (S.C.); (J.-W.K.); (Z.S.)
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Cakir B, Tomita Y, Yagi H, Romfh P, Allen W, Ko M, Chen P, Fu Z, Vakhshoori D, Smith LEH. In vivo noninvasive mitochondrial redox assessment of the optic nerve head to predict disease. PNAS NEXUS 2023; 2:pgad148. [PMID: 37265545 PMCID: PMC10230116 DOI: 10.1093/pnasnexus/pgad148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 03/19/2023] [Accepted: 04/11/2023] [Indexed: 06/03/2023]
Abstract
Eye diseases are diagnosed by visualizing often irreversible structural changes occurring late in disease progression, such as retinal ganglion cell loss in glaucoma. The retina and optic nerve head have high mitochondrial energy need. Early mitochondrial/energetics dysfunction may predict vulnerability to permanent structural changes. In the in vivo murine eye, we used light-based resonance Raman spectroscopy (RRS) to assess noninvasively the redox states of mitochondria and hemoglobin which reflect availability of electron donors (fuel) and acceptors (oxygen). As proof of principle, we demonstrated that the mitochondrial redox state at the optic nerve head correlates with later retinal ganglion loss after acute intraocular pressure (IOP) elevation. This technology can potentially map the metabolic health of eye tissue in vivo complementary to optical coherence tomography, defining structural changes. Early detection (and normalization) of mitochondrial dysfunction before irreversible damage could lead to prevention of permanent neural loss.
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Affiliation(s)
- Bertan Cakir
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Yohei Tomita
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Hitomi Yagi
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | | | - William Allen
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Minji Ko
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Peili Chen
- Pendar Technologies, Cambridge, MA 02138, USA
| | - Zhongjie Fu
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | | | - Lois E H Smith
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
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Fafure AA, Edem EE, Obisesan AO, Enye LA, Adekeye AO, Adetunji AE, Nebo KE, Olusegun AA, Fafure OE. Fermented maize slurry (Ogi) and its supernatant (Omidun) mitigate elevated intraocular pressure by modulating BDNF expression and glial plasticity in the retina-gut axis of glaucomatous rats. JOURNAL OF COMPLEMENTARY & INTEGRATIVE MEDICINE 2022; 19:887-896. [PMID: 34380184 DOI: 10.1515/jcim-2021-0114] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Accepted: 07/27/2021] [Indexed: 06/13/2023]
Abstract
OBJECTIVES Growing interest has been reported on the health benefits of fermented foods, which includes cognition enhancement and inflammation attenuation. BDNF is a known protectant against retinal degeneration, however, therapies that target this neurotrophic factor has been limited. Therefore, we assessed the reaction of BDNF and glial cells in glaucomatous rats and their response to treatment with fermented maize products. METHODS Thirty male adult rats were either injected via the episcleral vein with hypertonic saline to elevate intraocular pressure (IOP) or treated with fermented maize slurry (Ogi) or its supernatant (Omidun). Following sacrifice, the retina and duodenum were studied by immunohistochemical analysis using antibodies directed against GFAP, AIF-1 and BDNF. RESULTS Hypertonic saline injection produced hypertrophy of the Müller cells and increased GFAP and AIF-1 expression in the retina and gut when compared to the control. Treatment with Ogi and Omidun produced varying degrees of reduction of gliosis, protection against hypertonic saline-induced retinal ganglion cell loss, and reduced intraocular pressure. BDNF expression was downregulated following the hypertonic saline assault, while Omidun and Ogi treatment abrogated its reduction following the hypertonic saline assault. CONCLUSIONS Collectively, our findings suggest that acute elevation of IOP alters crosstalk between gut and retina with consequent aberrant activation of glial cells; and that probiotic bacteria like the lactic acid bacteria rich in fermented foods including Ogi and Omidun may offer neuroprotection to the ganglionic cells by attenuating the retinal glial reaction and improving BDNF activity.
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Affiliation(s)
- Adedamola Adediran Fafure
- Neuroscience Unit, Department of Anatomy, Faculty of Basic Medical Sciences, College of Medicine and Health Sciences, Afe Babalola University, Ado-Ekiti, Nigeria
| | - Edem Ekpenyong Edem
- Neuroscience Unit, Department of Anatomy, Faculty of Basic Medical Sciences, College of Medicine and Health Sciences, Afe Babalola University, Ado-Ekiti, Nigeria
| | - Abiola Oluwatosin Obisesan
- Department of Pharmaceutical Microbiology, Faculty of Pharmacy, College of Medicine and Health Sciences, Afe Babalola University, Ado-Ekiti, Nigeria
| | - Linus Anderson Enye
- Neuroscience Unit, Department of Anatomy, Faculty of Basic Medical Sciences, College of Medicine and Health Sciences, Afe Babalola University, Ado-Ekiti, Nigeria
| | - Adeshina Oloruntoba Adekeye
- Neuroscience Unit, Department of Anatomy, Faculty of Basic Medical Sciences, College of Medicine and Health Sciences, Afe Babalola University, Ado-Ekiti, Nigeria
| | - Adedeji Enitan Adetunji
- Neuroscience Unit, Department of Anatomy, Faculty of Basic Medical Sciences, College of Medicine and Health Sciences, Afe Babalola University, Ado-Ekiti, Nigeria
| | - Kate Eberechukwu Nebo
- Neuroscience Unit, Department of Anatomy, Faculty of Basic Medical Sciences, College of Medicine and Health Sciences, Afe Babalola University, Ado-Ekiti, Nigeria
| | - Adebayo Adeoluwa Olusegun
- Neuropharmacology Unit, Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, Afe-Babalola University, Ado-Ekiti, Nigeria
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Hydrogen sulfide supplement preserves mitochondrial function of retinal ganglion cell in a rat glaucoma model. Cell Tissue Res 2022; 389:171-185. [PMID: 35593936 DOI: 10.1007/s00441-022-03640-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 05/09/2022] [Indexed: 11/02/2022]
Abstract
Glaucoma is a neurodegenerative disease of visual system characterized by gradual loss of retinal ganglion cells (RGC). Since mitochondrial dysfunction of RGC is significantly involved in the pathological mechanisms of glaucoma, and hydrogen sulfide (H2S) takes part in the pathogeny of glaucoma and shows promising potential in restoring mitochondrial function in other neurons, the authors aimed to investigate the impact of H2S on mitochondrial function of RGC with a rat glaucoma model. An established chronic ocular hypertension (COH) rat model induced by injection of cross-linking hydrogel into anterior chamber was adopted, and a H2S donor, sodium hydrosulfide (NaHS), was selected to treat rats through intraperitoneal injection. After a period of 4 weeks, RGCs were isolated from the subjected rats with an immunopanning method and went through evaluations of mitochondrial membrane potential (MMP), mitochondrial permeability transition pore (MPTP) opening, intracellular Ca2 + level, reactive oxygen species (ROS) level, and cytosolic Cytochrome C distribution. The results showed that the mitochondrial function of RGC in experimental glaucoma was markedly improved by H2S supplement, being presented as stabilization of MMP, alleviation of MPTP opening, improvement of intracellular Ca2+ hemostasis, reduction of ROS accumulation, and inhibition of Cytochrome C release. Our study implicated that preservation of mitochondrial function by H2S probably plays a key role in protecting RGC in the context of glaucomatous neuropathy, and it is worth further deepgoing research to benefit the development of glaucoma treatment.
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Dias MS, Luo X, Ribas VT, Petrs-Silva H, Koch JC. The Role of Axonal Transport in Glaucoma. Int J Mol Sci 2022; 23:ijms23073935. [PMID: 35409291 PMCID: PMC8999615 DOI: 10.3390/ijms23073935] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 03/28/2022] [Accepted: 03/31/2022] [Indexed: 11/16/2022] Open
Abstract
Glaucoma is a neurodegenerative disease that affects the retinal ganglion cells (RGCs) and leads to progressive vision loss. The first pathological signs can be seen at the optic nerve head (ONH), the structure where RGC axons leave the retina to compose the optic nerve. Besides damage of the axonal cytoskeleton, axonal transport deficits at the ONH have been described as an important feature of glaucoma. Axonal transport is essential for proper neuronal function, including transport of organelles, synaptic components, vesicles, and neurotrophic factors. Impairment of axonal transport has been related to several neurodegenerative conditions. Studies on axonal transport in glaucoma include analysis in different animal models and in humans, and indicate that its failure happens mainly in the ONH and early in disease progression, preceding axonal and somal degeneration. Thus, a better understanding of the role of axonal transport in glaucoma is not only pivotal to decipher disease mechanisms but could also enable early therapies that might prevent irreversible neuronal damage at an early time point. In this review we present the current evidence of axonal transport impairment in glaucomatous neurodegeneration and summarize the methods employed to evaluate transport in this disease.
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Affiliation(s)
- Mariana Santana Dias
- Intermediate Laboratory of Gene Therapy and Viral Vectors, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Rio de Janeiro 21941-902, Brazil; (M.S.D.); (H.P.-S.)
| | - Xiaoyue Luo
- Department of Neurology, University Medical Center Göttingen, 37077 Göttingen, Germany;
| | - Vinicius Toledo Ribas
- Laboratory of Neurobiology, Department of Morphology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte 31270-901, Brazil;
| | - Hilda Petrs-Silva
- Intermediate Laboratory of Gene Therapy and Viral Vectors, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Rio de Janeiro 21941-902, Brazil; (M.S.D.); (H.P.-S.)
| | - Jan Christoph Koch
- Department of Neurology, University Medical Center Göttingen, 37077 Göttingen, Germany;
- Correspondence:
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12
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Di Pierdomenico J, Henderson DCM, Giammaria S, Smith VL, Jamet AJ, Smith CA, Hooper ML, Chauhan BC. Age and intraocular pressure in murine experimental glaucoma. Prog Retin Eye Res 2021; 88:101021. [PMID: 34801667 DOI: 10.1016/j.preteyeres.2021.101021] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 10/25/2021] [Accepted: 11/08/2021] [Indexed: 12/23/2022]
Abstract
Age and intraocular pressure (IOP) are the two most important risk factors for the development and progression of open-angle glaucoma. While IOP is commonly considered in models of experimental glaucoma (EG), most studies use juvenile or adult animals and seldom older animals which are representative of the human disease. This paper provides a concise review of how retinal ganglion cell (RGC) loss, the hallmark of glaucoma, can be evaluated in EG with a special emphasis on serial in vivo imaging, a parallel approach used in clinical practice. It appraises the suitability of EG models for the purpose of in vivo imaging and argues for the use of models that provide a sustained elevation of IOP, without compromise of the ocular media. In a study with parallel cohorts of adult (3-month-old, equivalent to 20 human years) and old (2-year-old, equivalent to 70 human years) mice, we compare the effects of elevated IOP on serial ganglion cell complex thickness and individual RGC dendritic morphology changes obtained in vivo. We also evaluate how age modulates the impact of elevated IOP on RGC somal and axonal density in histological analysis as well the density of melanopsin RGCs. We discuss the challenges of using old animals and emphasize the potential of single RGC imaging for understanding the pathobiology of RGC loss and evaluating new therapeutic avenues.
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Affiliation(s)
- Johnny Di Pierdomenico
- Retina and Optic Nerve Research Laboratory, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Delaney C M Henderson
- Retina and Optic Nerve Research Laboratory, Dalhousie University, Halifax, Nova Scotia, Canada; Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Sara Giammaria
- Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Victoria L Smith
- Retina and Optic Nerve Research Laboratory, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Aliénor J Jamet
- Retina and Optic Nerve Research Laboratory, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Corey A Smith
- Retina and Optic Nerve Research Laboratory, Dalhousie University, Halifax, Nova Scotia, Canada; Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Michele L Hooper
- Retina and Optic Nerve Research Laboratory, Dalhousie University, Halifax, Nova Scotia, Canada; Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Balwantray C Chauhan
- Retina and Optic Nerve Research Laboratory, Dalhousie University, Halifax, Nova Scotia, Canada; Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada; Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, Nova Scotia, Canada; Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada.
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13
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Sharif NA. Therapeutic Drugs and Devices for Tackling Ocular Hypertension and Glaucoma, and Need for Neuroprotection and Cytoprotective Therapies. Front Pharmacol 2021; 12:729249. [PMID: 34603044 PMCID: PMC8484316 DOI: 10.3389/fphar.2021.729249] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 08/18/2021] [Indexed: 12/11/2022] Open
Abstract
Damage to the optic nerve and the death of associated retinal ganglion cells (RGCs) by elevated intraocular pressure (IOP), also known as glaucoma, is responsible for visual impairment and blindness in millions of people worldwide. The ocular hypertension (OHT) and the deleterious mechanical forces it exerts at the back of the eye, at the level of the optic nerve head/optic disc and lamina cribosa, is the only modifiable risk factor associated with glaucoma that can be treated. The elevated IOP occurs due to the inability of accumulated aqueous humor (AQH) to egress from the anterior chamber of the eye due to occlusion of the major outflow pathway, the trabecular meshwork (TM) and Schlemm’s canal (SC). Several different classes of pharmaceutical agents, surgical techniques and implantable devices have been developed to lower and control IOP. First-line drugs to promote AQH outflow via the uveoscleral outflow pathway include FP-receptor prostaglandin (PG) agonists (e.g., latanoprost, travoprost and tafluprost) and a novel non-PG EP2-receptor agonist (omidenepag isopropyl, Eybelis®). TM/SC outflow enhancing drugs are also effective ocular hypotensive agents (e.g., rho kinase inhibitors like ripasudil and netarsudil; and latanoprostene bunod, a conjugate of a nitric oxide donor and latanoprost). One of the most effective anterior chamber AQH microshunt devices is the Preserflo® microshunt which can lower IOP down to 10–13 mmHg. Other IOP-lowering drugs and devices on the horizon will be also discussed. Additionally, since elevated IOP is only one of many risk factors for development of glaucomatous optic neuropathy, a treatise of the role of inflammatory neurodegeneration of the optic nerve and retinal ganglion cells and appropriate neuroprotective strategies to mitigate this disease will also be reviewed and discussed.
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Affiliation(s)
- Najam A Sharif
- Global Alliances and External Research, Ophthalmology Innovation Center, Santen Inc., Emeryville, CA, United States
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14
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Lo Faro V, Ten Brink JB, Snieder H, Jansonius NM, Bergen AA. Genome-wide CNV investigation suggests a role for cadherin, Wnt, and p53 pathways in primary open-angle glaucoma. BMC Genomics 2021; 22:590. [PMID: 34348663 PMCID: PMC8336345 DOI: 10.1186/s12864-021-07846-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 06/18/2021] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND To investigate whether copy number variations (CNVs) are implicated in molecular mechanisms underlying primary open-angle glaucoma (POAG), we used genotype data of POAG individuals and healthy controls from two case-control studies, AGS (n = 278) and GLGS-UGLI (n = 1292). PennCNV, QuantiSNP, and cnvPartition programs were used to detect CNV. Stringent quality controls at both sample and marker levels were applied. The identified CNVs were intersected in CNV region (CNVR). After, we performed burden analysis, CNV-genome-wide association analysis, gene set overrepresentation and pathway analysis. In addition, in human eye tissues we assessed the expression of the genes lying within significant CNVRs. RESULTS We reported a statistically significant greater burden of CNVs in POAG cases compared to controls (p-value = 0,007). In common between the two cohorts, CNV-association analysis identified statistically significant CNVRs associated with POAG that span 11 genes (APC, BRCA2, COL3A1, HLA-DRB1, HLA-DRB5, HLA-DRB6, MFSD8, NIPBL, SCN1A, SDHB, and ZDHHC11). Functional annotation and pathway analysis suggested the involvement of cadherin, Wnt signalling, and p53 pathways. CONCLUSIONS Our data suggest that CNVs may have a role in the susceptibility of POAG and they can reveal more information on the mechanism behind this disease. Additional genetic and functional studies are warranted to ascertain the contribution of CNVs in POAG.
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Affiliation(s)
- Valeria Lo Faro
- Department of Ophthalmology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.,Departments of Clinical Genetics and Ophthalmology, Amsterdam University Medical Center (AMC), Location AMC K2-217
- AMC-UvA, P.O.Box 22700, 1100 DE, Amsterdam, The Netherlands
| | - Jacoline B Ten Brink
- Departments of Clinical Genetics and Ophthalmology, Amsterdam University Medical Center (AMC), Location AMC K2-217
- AMC-UvA, P.O.Box 22700, 1100 DE, Amsterdam, The Netherlands
| | - Harold Snieder
- Department of Epidemiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Nomdo M Jansonius
- Department of Ophthalmology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Arthur A Bergen
- Departments of Clinical Genetics and Ophthalmology, Amsterdam University Medical Center (AMC), Location AMC K2-217
- AMC-UvA, P.O.Box 22700, 1100 DE, Amsterdam, The Netherlands. .,Department of Ophthalmology, Amsterdam UMC, Location AMC, Amsterdam, The Netherlands. .,Netherlands Institute for Neuroscience (NIN-KNAW), Amsterdam, The Netherlands.
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15
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Bhalla M, Heisler M, Mammo Z, Ju MJ, Sarunic MV, Navajas EV, Warner S, Schendel S, Gill KS. Investigation of the Peripapillary Choriocapillaris in Normal Tension Glaucoma, Primary Open-angle Glaucoma, and Control Eyes. J Glaucoma 2021; 30:682-689. [PMID: 33927150 DOI: 10.1097/ijg.0000000000001861] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 04/01/2021] [Indexed: 11/26/2022]
Abstract
PRECIS The peripapillary choriocapillaris (CC) was observed to be significantly impaired in normal tension glaucoma (NTG) subjects compared with normal controls using optical coherence tomography angiography (OCTA). PURPOSE The aim was to quantitatively evaluate the peripapillary CC in NTG, primary open-angle glaucoma (POAG), and control eyes using OCTA. MATERIALS AND METHODS Ninety eyes (30 controls, 30 NTG, and 30 POAG) from 73 patients were imaged using the Zeiss Plex Elite 9000. Five repeat 3×3 mm OCTA scans were acquired both nasally and temporally to the optic disc and subsequently averaged. Four CC flow deficit (FD) measures were calculated using the fuzzy C-means approach: FD density (FDD), mean FD size (MFDS), FD number (FDN), and FD area (FDA). RESULTS Temporal NTG CC parameters were associated with visual field index and mean deviation (P<0.05). The control group showed a significantly lower nasal FDD (nasal: 3.79±1.26%, temporal: 4.48±1.73%, P=0.03), FDN (nasal: 156.43±38.44, temporal: 178.40±45.68, P=0.02), and FDA (nasal: 0.22±0.08, temporal: 0.26±0.10, P=0.03) when compared with temporal optic disc. The NTG group showed a significantly higher FDD (NTG: 5.04±2.38%, control: 3.79±1.26%, P=0.03), FDN (NTG: 185.90±56.66, control: 156.43±38.44, P=0.04), and FDA (NTG: 0.30±0.14 mm2, control: 0.22±0.08 mm2, P=0.03) nasal to the optic disc compared with controls. CONCLUSIONS Association between CC parameters and glaucoma severity in NTG, but not POAG subjects, suggests vascular abnormalities may be a potential factor in the multifactorial process of glaucoma damage in NTG patients.
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Affiliation(s)
| | - Morgan Heisler
- School of Engineering Science, Simon Fraser University, Burnaby, BC, Canada
| | - Zaid Mammo
- Department of Ophthalmology and Visual Sciences
| | - Myeong Jin Ju
- Department of Ophthalmology and Visual Sciences
- School of Biomedical Engineering, University of British Columbia, Vancouver
| | - Marinko V Sarunic
- School of Engineering Science, Simon Fraser University, Burnaby, BC, Canada
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16
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Trans-synaptic degeneration in the visual pathway: Neural connectivity, pathophysiology, and clinical implications in neurodegenerative disorders. Surv Ophthalmol 2021; 67:411-426. [PMID: 34146577 DOI: 10.1016/j.survophthal.2021.06.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 06/06/2021] [Accepted: 06/07/2021] [Indexed: 12/13/2022]
Abstract
There is a strong interrelationship between eye and brain diseases. It has been shown that neurodegenerative changes can spread bidirectionally in the visual pathway along neuronal projections. For example, damage to retinal ganglion cells in the retina leads to degeneration of the visual cortex (anterograde degeneration) and vice versa (retrograde degeneration). The underlying mechanisms of this process, known as trans-synaptic degeneration (TSD), are unknown, but TSD contributes to the progression of numerous neurodegenerative disorders, leading to clinical and functional deterioration. The hierarchical structure of the visual system comprises of a strong topographic connectivity between the retina and the visual cortex and therefore serves as an ideal model to study the cellular effect, clinical manifestations, and deterioration extent of TSD. With this review we provide comprehensive information about the neural connectivity, synapse function, molecular changes, and pathophysiology of TSD in visual pathways. We then discuss its bidirectional nature and clinical implications in neurodegenerative diseases. A thorough understanding of TSD in the visual pathway can provide insights into progression of neurodegenerative disorders and its potential as a therapeutic target.
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17
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Khatib TZ, Osborne A, Yang S, Ali Z, Jia W, Manyakin I, Hall K, Watt R, Widdowson PS, Martin KR. Receptor-ligand supplementation via a self-cleaving 2A peptide-based gene therapy promotes CNS axonal transport with functional recovery. SCIENCE ADVANCES 2021; 7:eabd2590. [PMID: 33789891 PMCID: PMC8011959 DOI: 10.1126/sciadv.abd2590] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 02/09/2021] [Indexed: 06/12/2023]
Abstract
Gene replacement approaches are leading to a revolution in the treatment of previously debilitating monogenic neurological conditions. However, the application of gene therapy to complex polygenic conditions has been limited. Down-regulation or dysfunction of receptor expression in the disease state or in the presence of excess ligand has been shown to compromise therapeutic efficacy. Here, we offer evidence that combined overexpression of both brain-derived neurotrophic factor and its receptor, tropomyosin receptor kinase B, is more effective in stimulating axonal transport than either receptor administration or ligand administration alone. We also show efficacy in experimental glaucoma and humanized tauopathy models. Simultaneous administration of a ligand and its receptor by a single gene therapy vector overcomes several problems relating to ligand deficiency and receptor down-regulation that may be relevant to multiple neurodegenerative diseases. This approach shows promise as a strategy to target intrinsic mechanisms to improve neuronal function and facilitate repair.
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Affiliation(s)
- Tasneem Z Khatib
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.
- Eye Department, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
- Medical Sciences Division, University of Oxford, Oxford, UK
| | - Andrew Osborne
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
- Quethera Ltd., Cambridge, UK
- Ikarovec Ltd., Norwich Innovation Centre, Norwich, UK
| | - Sujeong Yang
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Zara Ali
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
- School of Clinical Medicine, University of Cambridge, Cambridge, UK
| | - Wanyi Jia
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Ilya Manyakin
- Department of Physics, University of Cambridge, Cambridge, UK
| | - Katie Hall
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Robert Watt
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Peter S Widdowson
- Quethera Ltd., Cambridge, UK
- Ikarovec Ltd., Norwich Innovation Centre, Norwich, UK
| | - Keith R Martin
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.
- Eye Department, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
- Quethera Ltd., Cambridge, UK
- Cambridge NIHR Biomedical Research Centre, Cambridge, UK
- Wellcome Trust-MRC Cambridge Stem Cell Institute, University of Cambridge, Cambridge, UK
- Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Australia
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia
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18
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Chan JW, Chan NCY, Sadun AA. Glaucoma as Neurodegeneration in the Brain. Eye Brain 2021; 13:21-28. [PMID: 33500674 PMCID: PMC7822087 DOI: 10.2147/eb.s293765] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 01/07/2021] [Indexed: 12/31/2022] Open
Abstract
Glaucoma, a group of diseases characterized by progressive optic nerve degeneration that results in irreversible blindness, can be considered a neurodegenerative disorder of both the eye and the brain. Increasing evidence from human and animal studies have shown that glaucoma shares some common neurodegenerative pathways with Alzheimer’s disease (AD) and other tauopathies, such as chronic traumatic encephalopathy (CTE) and frontotemporal dementia. This hypothesis is based on the focal adhesion pathway hypothesis and the spreading hypothesis of tau. Not only has the Apolipoprotein E (APOE) gene been shown to be associated with AD, but also with primary open angle glaucoma (POAG). This review will highlight the relevant literature in the past 20 years from PubMed that show the pathogenic overlap between POAG and AD. Neurodegenerative pathways that contribute to transsynaptic neurodegeneration in AD and other tauopathies might also be similar to those in glaucomatous neurodegeneration.
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Affiliation(s)
- Jane W Chan
- Department of Ophthalmology, Doheny Eye Institute, Pasadena, CA, USA
| | - Noel C Y Chan
- Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, N.T., Hong Kong, People's Republic of China
| | - Alfredo A Sadun
- Department of Ophthalmology, Doheny Eye Institute, Pasadena, CA, USA.,Department of Ophthalmology, University of California, Los Angeles, CA, USA
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19
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Huo YJ, Thomas R, Li L, Cao K, Wang HZ, Wang NL. Comparison of Peripapillary Retinal Nerve Fiber Layer Thickness, Functional Subzones, and Macular Ganglion Cell-Inner Plexiform Layer in Differentiating Patients With Mild, Moderate, and Severe Open-angle Glaucoma. J Glaucoma 2021; 29:761-766. [PMID: 32657819 DOI: 10.1097/ijg.0000000000001598] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PRéCIS:: Based on 6 functional subzones of peripapillary retinal nerve fiber layer (pRNFL) thickness, the glaucoma detection ability of zone 2 and zone 4 was high and comparable with that of mean pRNFL in glaucoma groups. PURPOSE To compare diagnostic performance of pRNFL subzones, mean pRNFL thickness, and macular ganglion cell-inner plexiform layer (mGCIPL) in mild, moderate, and severe open-angle glaucoma. MATERIALS AND METHODS One hundred eighty-one patients with open-angle glaucoma (318 eyes: 122 mild, 60 moderate, and 136 severe glaucoma) and 70 normal subjects underwent spectral-domain optical coherence tomography measurements. FORUM software was used to determine subzone pRNFL thickness mapping the visual field to the optic disc (6 zones). The thickness and area under the receiver operating curve (AUROC) of each parameter were compared between groups. DeLong's method was used to compare AUROCs between mean pRNFL and mGCIPL and each zone of spectral-domain optical coherence tomography parameters. RESULTS Mean pRNFL thickness (99.81±10.06 μm) and mGCIPL thickness (83.24±5.91 μm) were higher in controls compared with glaucoma (67.42±13.22 and 63.31±10.85 μm; P<0.001). Mean pRNFL had the best diagnostic performance in mild (0.957) and severe (1.000) glaucoma. Of the 6 zonal parameters, zone 2 (associated with the inferior temporal sector) best discriminated glaucomatous changes between controls and mild and moderate (0.941 and 0.988). Zone 4 (associated with the superior temporal sector) best discriminated glaucomatous changes between controls and severe glaucoma (0.998). AUROCs for zone 2 and zone 4 were not significantly different from mean pRNFL and mGCIPL in all glaucoma groups (all P>0.0038). CONCLUSIONS Mean pRNFL had the best diagnostic performance in mild and severe glaucoma. Glaucoma detection ability of zone 2 and zone 4 was high and comparable with that of mean pRNFL and mGCIPL in all glaucoma groups.
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Affiliation(s)
- Yan Jiao Huo
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Lab
| | - Ravi Thomas
- Beijing Institute of Ophthalmology, Beijing, China.,Queensland Eye Institute.,University of Queensland, Brisbane, Australia
| | - Lei Li
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Lab
| | - Kai Cao
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Lab
| | - Huai Zhou Wang
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Lab
| | - Ning Li Wang
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Lab.,Beijing Institute of Ophthalmology, Beijing, China
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20
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Pazos M, Biarnés M, Blasco-Alberto A, Dyrda A, Luque-Fernández MÁ, Gómez A, Mora C, Milla E, Muniesa M, Antón A, Díaz-Alemán VT. SD-OCT peripapillary nerve fibre layer and ganglion cell complex parameters in glaucoma: principal component analysis. Br J Ophthalmol 2020; 105:496-501. [PMID: 32493759 DOI: 10.1136/bjophthalmol-2020-316296] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 04/13/2020] [Accepted: 05/10/2020] [Indexed: 12/31/2022]
Abstract
BACKGROUND/AIMS To identify objective glaucoma-related structural features based on peripapillary (p) and macular (m) spectral domain optical coherence tomography (SD-OCT) parameters and assess their discriminative ability between healthy and glaucoma patients. METHODS Two hundred and sixty eyes (91 controls and 169 glaucoma) were included in this prospective study. After a complete examination, all participants underwent the posterior pole and the peripapillary retinal nerve fibre layer (pRNFL) protocols of the Spectralis SD-OCT. Principal component analysis (PCA), a data reduction method, was applied to identify and characterise the main information provided by the ganglion cell complex (GCC). The discriminative ability between healthy and glaucomatous eyes of the first principal components (PCs) was compared with that of conventional SD-OCT parameters (pRNFL, macular RNFL (mRNFL), macular ganglion cell layer (mGCL)and macular inner plexiform layer (mIPL)) using 10-fold cross-validated areas under the curve (AUC). RESULTS The first PC explained 58% of the total information contained in the GCC and the pRNFL parameters and was the result of a general combination of almost all variables studied (diffuse distribution). Other PCs were driven mainly by pRNFL and mRNFL measurements. PCs and pRNFL had similar AUC (0.95 vs 0.96, p=0.88), and outperformed the other structural measurements: mRNFL (0.91, p=0.002), mGCL (0.92, p=0.02) and mIPL (0.92, p=0.0001). CONCLUSIONS PCA identified a diffuse representation of the papillary and macular SD-OCT parameters as the most important PC to summarise structural data in healthy and glaucomatous eyes. PCs and pRNFL parameters showed the greatest discriminative ability between healthy and glaucoma cases.
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Affiliation(s)
- Marta Pazos
- Institut Clínic d'Oftalmologia, Hospital Clínic de Barcelona. Universitat de Barcelona, Barcelona, Spain .,Institut de la Màcula, Barcelona Macula Foundation (Hospital Quirón-Teknon), Barcelona, Spain
| | - Marc Biarnés
- Institut de la Màcula, Barcelona Macula Foundation (Hospital Quirón-Teknon), Barcelona, Spain
| | - Andrés Blasco-Alberto
- Ophthalmology, Hospital Universitario de Canarias, Universidad de la Laguna, Tenerife, Spain
| | - Agnieszka Dyrda
- Glaucoma and Research, Institut Català de Retina, Barcelona, Spain
| | - Miguel Ángel Luque-Fernández
- Non-communicable Disease and Cancer Epidemiology Group, Biomedical Research Institute of Granada (ibs.GRANADA), Granada, Spain.,Non-communicable Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
| | - Alicia Gómez
- Glaucoma and Research, Institut Català de Retina, Barcelona, Spain
| | - Clara Mora
- Ophthalmology, Hospital de l'Esperança-Parc de Salut Mar, Barcelona, Spain
| | - Elena Milla
- Institut Clínic d'Oftalmologia, Hospital Clínic de Barcelona. Universitat de Barcelona, Barcelona, Spain
| | - MªJesús Muniesa
- Institut Clínic d'Oftalmologia, Hospital Clínic de Barcelona. Universitat de Barcelona, Barcelona, Spain
| | - Alfonso Antón
- Glaucoma and Research, Institut Català de Retina, Barcelona, Spain.,Ophthalmology, Hospital de l'Esperança-Parc de Salut Mar, Barcelona, Spain.,Ophthalmology, Universitat Internacional de Catalunya Facultat de Medicina i Ciències de la Salut, Sant Cugat del Valles, Spain
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21
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Mirra S, Marfany G, Garcia-Fernàndez J. Under pressure: Cerebrospinal fluid contribution to the physiological homeostasis of the eye. Semin Cell Dev Biol 2019; 102:40-47. [PMID: 31761444 DOI: 10.1016/j.semcdb.2019.11.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 11/05/2019] [Indexed: 01/27/2023]
Abstract
The cerebrospinal fluid (CSF) is a waterly, colorless fluid contained within the brain ventricles and the cranial and spinal subarachnoid spaces. CSF physiological functions range from hydromechanical protection of the central nervous system (CNS) to CNS modulation of developmental processes and regulation of interstitial fluid homeostasis. Optic nerve (ON) is surrounded by CSF circulating in the subarachnoid spaces and is exposed to both CSF (CSFP) and intra ocular (IOP) pressures, which converge at the lamina cribrosa (LC) as two opposite forces. The trans-lamina cribrosa pressure gradient (TLPG) is defined as IOP - CSFP and its alterations (due either to an elevation in IOP or a reduction in ICP) could result in structural damaging of the ON, including glaucomatous changes. The purpose of this review is to update the readers on the CSF contribution in controlling the functions/dysfunctions of ON by regulating homeostasis at LC. We also highlight emerging parallelisms regarding the expression of cilia-related genes in the regulation of common functions of body fluids in both brain and eye structures.
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Affiliation(s)
- Serena Mirra
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, and Institut de Biomedicina (IBUB), University of Barcelona, Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Spain.
| | - Gemma Marfany
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, and Institut de Biomedicina (IBUB), University of Barcelona, Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Spain.
| | - Jordi Garcia-Fernàndez
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, and Institut de Biomedicina (IBUB), University of Barcelona, Barcelona, Spain.
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22
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Bhandari A, Smith JC, Zhang Y, Jensen AA, Reid L, Goeser T, Fan S, Ghate D, Van Hook MJ. Early-Stage Ocular Hypertension Alters Retinal Ganglion Cell Synaptic Transmission in the Visual Thalamus. Front Cell Neurosci 2019; 13:426. [PMID: 31607867 PMCID: PMC6761307 DOI: 10.3389/fncel.2019.00426] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 09/04/2019] [Indexed: 12/21/2022] Open
Abstract
Axonopathy is a hallmark of many neurodegenerative diseases including glaucoma, where elevated intraocular pressure (ocular hypertension, OHT) stresses retinal ganglion cell (RGC) axons as they exit the eye and form the optic nerve. OHT causes early changes in the optic nerve such as axon atrophy, transport inhibition, and gliosis. Importantly, many of these changes appear to occur prior to irreversible neuronal loss, making them promising points for early diagnosis of glaucoma. It is unknown whether OHT has similarly early effects on the function of RGC output to the brain. To test this possibility, we elevated eye pressure in mice by anterior chamber injection of polystyrene microbeads. Five weeks post-injection, bead-injected eyes showed a modest RGC loss in the peripheral retina, as evidenced by RBPMS antibody staining. Additionally, we observed reduced dendritic complexity and lower spontaneous spike rate of On-αRGCs, targeted for patch clamp recording and dye filling using a Opn4-Cre reporter mouse line. To determine the influence of OHT on retinal projections to the brain, we expressed Channelrhodopsin-2 (ChR2) in melanopsin-expressing RGCs by crossing the Opn4-Cre mouse line with a ChR2-reporter mouse line and recorded post-synaptic responses in thalamocortical relay neurons in the dorsal lateral geniculate nucleus (dLGN) of the thalamus evoked by stimulation with 460 nm light. The use of a Opn4-Cre reporter system allowed for expression of ChR2 in a narrow subset of RGCs responsible for image-forming vision in mice. Five weeks following OHT induction, paired pulse and high-frequency stimulus train experiments revealed that presynaptic vesicle release probability at retinogeniculate synapses was elevated. Additionally, miniature synaptic current frequency was slightly reduced in brain slices from OHT mice and proximal dendrites of post-synaptic dLGN relay neurons, assessed using a Sholl analysis, showed a reduced complexity. Strikingly, these changes occurred prior to major loss of RGCs labeled with the Opn4-Cre mouse, as indicated by immunofluorescence staining of ChR2-expressing retinal neurons. Thus, OHT leads to pre- and post-synaptic functional and structural changes at retinogeniculate synapses. Along with RGC dendritic remodeling and optic nerve transport changes, these retinogeniculate synaptic changes are among the earliest signs of glaucoma.
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Affiliation(s)
- Ashish Bhandari
- Department of Ophthalmology and Visual Sciences, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States
| | - Jennie C Smith
- Department of Ophthalmology and Visual Sciences, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States
| | - Yang Zhang
- Department of Ophthalmology and Visual Sciences, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States.,Creighton University School of Medicine, Omaha, NE, United States.,Department of Ophthalmology and Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States
| | - Aaron A Jensen
- Department of Ophthalmology and Visual Sciences, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States
| | - Lisa Reid
- Department of Ophthalmology and Visual Sciences, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States
| | - Toni Goeser
- Department of Ophthalmology and Visual Sciences, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States
| | - Shan Fan
- Department of Ophthalmology and Visual Sciences, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States
| | - Deepta Ghate
- Department of Ophthalmology and Visual Sciences, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States
| | - Matthew J Van Hook
- Department of Ophthalmology and Visual Sciences, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States
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23
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Claes M, De Groef L, Moons L. Target-Derived Neurotrophic Factor Deprivation Puts Retinal Ganglion Cells on Death Row: Cold Hard Evidence and Caveats. Int J Mol Sci 2019; 20:E4314. [PMID: 31484425 PMCID: PMC6747494 DOI: 10.3390/ijms20174314] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 08/28/2019] [Accepted: 08/30/2019] [Indexed: 12/14/2022] Open
Abstract
Glaucoma and other optic neuropathies are characterized by axonal transport deficits. Axonal cargo travels back and forth between the soma and the axon terminus, a mechanism ensuring homeostasis and the viability of a neuron. An example of vital molecules in the axonal cargo are neurotrophic factors (NTFs). Hindered retrograde transport can cause a scarcity of those factors in the retina, which in turn can tilt the fate of retinal ganglion cells (RGCs) towards apoptosis. This postulation is one of the most widely recognized theories to explain RGC death in the disease progression of glaucoma and is known as the NTF deprivation theory. For several decades, research has been focused on the use of NTFs as a novel neuroprotective glaucoma treatment. Until now, results in animal models have been promising, but translation to the clinic has been highly disappointing. Are we lacking important knowledge to lever NTF therapies towards the therapeutic armamentarium? Or did we get the wrong end of the stick regarding the NTF deprivation theory? In this review, we will tackle the existing evidence and caveats advocating for and against the target-derived NTF deprivation theory in glaucoma, whilst digging into associated therapy efforts.
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Affiliation(s)
- Marie Claes
- Laboratory of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, 3000 Leuven, Belgium
| | - Lies De Groef
- Laboratory of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, 3000 Leuven, Belgium
| | - Lieve Moons
- Laboratory of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, 3000 Leuven, Belgium.
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24
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Zeng Y, Qian H, Wu Z, Marangoni D, Sieving PA, Bush RA. AAVrh-10 transduces outer retinal cells in rodents and rabbits following intravitreal administration. Gene Ther 2019; 26:386-398. [PMID: 31308478 DOI: 10.1038/s41434-019-0094-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 04/09/2019] [Accepted: 04/28/2019] [Indexed: 01/11/2023]
Abstract
Recombinant adeno-associated virus (rAAV) has been widely used for gene delivery in animal models and successfully applied in clinical trials for treating inherited retinal disease. Although subretinal delivery of AAVs can effectively transduce photoreceptors and/or retinal pigmental epithelium (RPE), cells most affected by inherited retinal diseases, the procedure is invasive and complicated, and only delivers the gene to a limited retinal area. AAVs can also be delivered intravitreally to the retina, a much less invasive nonsurgical procedure. However, intravitreal administration of non-modified AAV serotypes tends to transduce only ganglion cells and inner nuclear layer cells. To date, most non-modified AAV serotypes that have been identified are incapable of efficiently transducing photoreceptors and/or RPE when delivered intravitreally. In this study, we investigate the retinal tropism of AAVrh10 vector administered by intravitreal injection to mouse, rat, and rabbit eyes. Our results demonstrate that AAVrh10 is capable of transducing not only inner retinal cells, but also outer retinal cells in all three species, though the transduction efficiency in rabbit was low. In addition, AAVrh10 preferentially transduced outer retinal cells in mouse models of retinal disease. Therefore, AAVrh10 vector could be a useful candidate to intravitreally deliver genes to photoreceptor and RPE cells.
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Affiliation(s)
- Yong Zeng
- Section on Translational Research for Retinal and Macular Degeneration, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - Haohua Qian
- National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Zhijian Wu
- National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Dario Marangoni
- Section on Translational Research for Retinal and Macular Degeneration, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - Paul A Sieving
- Section on Translational Research for Retinal and Macular Degeneration, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA.,National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Ronald A Bush
- Section on Translational Research for Retinal and Macular Degeneration, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA.
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25
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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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26
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Alqawlaq S, Flanagan JG, Sivak JM. All roads lead to glaucoma: Induced retinal injury cascades contribute to a common neurodegenerative outcome. Exp Eye Res 2018; 183:88-97. [PMID: 30447198 DOI: 10.1016/j.exer.2018.11.005] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 11/02/2018] [Accepted: 11/06/2018] [Indexed: 11/25/2022]
Abstract
Glaucoma describes a distinct optic neuropathy with complex etiology and a variety of associated risk factors, but with similar pathological endpoints. Risk factors such as age, increased intraocular pressure (IOP), low mean arterial pressure, and autoimmune disease, can all be associated with death of retinal ganglion cells (RGCs) and optic nerve head remodeling. Today, IOP management remains the standard of care, even though IOP elevation is not pathognomonic of glaucoma, and patients can continue to lose vision despite effective IOP control. A contemporary view of glaucoma as a complex, neurodegenerative disease has developed, along with the recognition of a need for new disease modifying retinal treatment strategies and improved outcomes. However, the distinction between risk factors triggering the disease process and retinal injury responses is not always clear. In this review, we attempt to distinguish between the various triggers, and their association with subsequent key RGC injury mechanisms. We propose that distinct glaucomatous risk factors result in similar retinal and optic nerve injury cascades, including oxidative and metabolic stress, glial reactivity, and altered inflammatory responses, which induce common molecular signals to induce RGC apoptosis. This organization forms a coherent disease framework and presents conserved targets for therapeutic intervention that are not limited to specific risk factors.
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Affiliation(s)
- Samih Alqawlaq
- Department of Vision Science, Krembil Research Institute, University Health Network, Toronto, ON, Canada; Vision Science Research Program, Ophthalmology and Vision Science, University of Toronto, Toronto, ON, Canada; Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - John G Flanagan
- School of Optometry and Vision Science Program, University of California at Berkeley, Berkeley, CA, USA
| | - Jeremy M Sivak
- Department of Vision Science, Krembil Research Institute, University Health Network, Toronto, ON, Canada; Vision Science Research Program, Ophthalmology and Vision Science, University of Toronto, Toronto, ON, Canada; Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.
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27
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Rabesandratana O, Goureau O, Orieux G. Pluripotent Stem Cell-Based Approaches to Explore and Treat Optic Neuropathies. Front Neurosci 2018; 12:651. [PMID: 30294255 PMCID: PMC6158340 DOI: 10.3389/fnins.2018.00651] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 08/30/2018] [Indexed: 12/15/2022] Open
Abstract
Sight is a major sense for human and visual impairment profoundly affects quality of life, especially retinal degenerative diseases which are the leading cause of irreversible blindness worldwide. As for other neurodegenerative disorders, almost all retinal dystrophies are characterized by the specific loss of one or two cell types, such as retinal ganglion cells, photoreceptor cells, or retinal pigmented epithelial cells. This feature is a critical point when dealing with cell replacement strategies considering that the preservation of other cell types and retinal circuitry is a prerequisite. Retinal ganglion cells are particularly vulnerable to degenerative process and glaucoma, the most common optic neuropathy, is a frequent retinal dystrophy. Cell replacement has been proposed as a potential approach to take on the challenge of visual restoration, but its application to optic neuropathies is particularly challenging. Many obstacles need to be overcome before any clinical application. Beyond their survival and differentiation, engrafted cells have to reconnect with both upstream synaptic retinal cell partners and specific targets in the brain. To date, reconnection of retinal ganglion cells with distal central targets appears unrealistic since central nervous system is refractory to regenerative processes. Significant progress on the understanding of molecular mechanisms that prevent central nervous system regeneration offer hope to overcome this obstacle in the future. At the same time, emergence of reprogramming of human somatic cells into pluripotent stem cells has facilitated both the generation of new source of cells with therapeutic potential and the development of innovative methods for the generation of transplantable cells. In this review, we discuss the feasibility of stem cell-based strategies applied to retinal ganglion cells and optic nerve impairment. We present the different strategies for the generation, characterization and the delivery of transplantable retinal ganglion cells derived from pluripotent stem cells. The relevance of pluripotent stem cell-derived retinal organoid and retinal ganglion cells for disease modeling or drug screening will be also introduced in the context of optic neuropathies.
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Affiliation(s)
| | - Olivier Goureau
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Gaël Orieux
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
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28
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Sharif NA. iDrugs and iDevices Discovery Research: Preclinical Assays, Techniques, and Animal Model Studies for Ocular Hypotensives and Neuroprotectants. J Ocul Pharmacol Ther 2018; 34:7-39. [PMID: 29323613 DOI: 10.1089/jop.2017.0125] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Discovery ophthalmic research is centered around delineating the molecular and cellular basis of ocular diseases and finding and exploiting molecular and genetic pathways associated with them. From such studies it is possible to determine suitable intervention points to address the disease process and hopefully to discover therapeutics to treat them. An investigational new drug (IND) filing for a new small-molecule drug, peptide, antibody, genetic treatment, or a device with global health authorities requires a number of preclinical studies to provide necessary safety and efficacy data. Specific regulatory elements needed for such IND-enabling studies are beyond the scope of this article. However, to enhance the overall data packages for such entities and permit high-quality foundation-building publications for medical affairs, additional research and development studies are always desirable. This review aims to provide examples of some target localization/verification, ocular drug discovery processes, and mechanistic and portfolio-enhancing exploratory investigations for candidate drugs and devices for the treatment of ocular hypertension and glaucomatous optic neuropathy (neurodegeneration of retinal ganglion cells and their axons). Examples of compound screening assays, use of various technologies and techniques, deployment of animal models, and data obtained from such studies are also presented.
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Affiliation(s)
- Najam A Sharif
- 1 Global Alliances & External Research , Santen Incorporated, Emeryville, California.,2 Department of Pharmaceutical Sciences, Texas Southern University , Houston, Texas.,3 Department of Pharmacology and Neuroscience, University of North Texas Health Sciences Center , Fort Worth, Texas
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29
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Pazos M, Dyrda AA, Biarnés M, Gómez A, Martín C, Mora C, Fatti G, Antón A. Diagnostic Accuracy of Spectralis SD OCT Automated Macular Layers Segmentation to Discriminate Normal from Early Glaucomatous Eyes. Ophthalmology 2017; 124:1218-1228. [DOI: 10.1016/j.ophtha.2017.03.044] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 03/21/2017] [Accepted: 03/21/2017] [Indexed: 11/17/2022] Open
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30
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Bordone MP, González Fleitas MF, Pasquini LA, Bosco A, Sande PH, Rosenstein RE, Dorfman D. Involvement of microglia in early axoglial alterations of the optic nerve induced by experimental glaucoma. J Neurochem 2017; 142:323-337. [PMID: 28498493 DOI: 10.1111/jnc.14070] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 04/21/2017] [Accepted: 05/02/2017] [Indexed: 12/31/2022]
Abstract
Glaucoma is a leading cause of blindness, characterized by retinal ganglion cell (RGC) loss and optic nerve (ON) damage. Cumulative evidence suggests glial cell involvement in the degeneration of the ON and RGCs. We analyzed the contribution of microglial reactivity to early axoglial alterations of the ON in an induced model of ocular hypertension. For this purpose, vehicle or chondroitin sulfate (CS) were weekly injected into the eye anterior chamber from Wistar rats for different intervals. The amount of Brn3a(+) RGC significantly decreased in CS-injected eyes for 10 and 15 (but not 6) weeks. A reduction in anterograde transport of β-subunit cholera toxin was observed in the superior colliculus and the lateral geniculate nucleus contralateral to CS-injected eyes for 6 and 15 weeks. A disruption of cholera toxin β-subunit transport was observed at the proximal myelinated ON. A significant decrease in phosphorylated neurofilament heavy chain immunoreactivity, an increase in ionized calcium-binding adaptor molecule 1(+), ED1(+) (microglial markers), and glial fibrillary acidic protein (astrocytes) (+) area, and decreased luxol fast blue staining were observed in the ON at 6 and 15 weeks of ocular hypertension. Microglial reactivity involvement was examined through a daily treatment with minocycline (30 mg/kg, i.p.) for 2 weeks, after 4 weeks of ocular hypertension. Minocycline prevented the increase in ionized calcium-binding adaptor molecule 1(+), ED-1(+), and glial fibrillary acidic protein(+) area, the decrease in phosphorylated neurofilament heavy-chain immunoreactivity and luxol fast blue staining, and the deficit in anterograde transport induced by 6 weeks of ocular hypertension. Thus, targeting microglial reactivity might prevent early axoglial alterations in the glaucomatous ON. Cover Image for this issue: doi: 10.1111/jnc.13807.
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Affiliation(s)
- Melina P Bordone
- Laboratory of Retinal Neurochemistry and Experimental Ophthalmology, Department of Human Biochemistry, School of Medicine/CEFyBO, University of Buenos Aires/CONICET, Buenos Aires, Argentina
| | - María F González Fleitas
- Laboratory of Retinal Neurochemistry and Experimental Ophthalmology, Department of Human Biochemistry, School of Medicine/CEFyBO, University of Buenos Aires/CONICET, Buenos Aires, Argentina
| | - Laura A Pasquini
- Department of Biological Chemistry and Institute of Chemistry and Biological Physicochemistry, IQUIFIB, School of Pharmacy and Biochemistry, University of Buenos Aires, CONICET, Buenos Aires, Argentina
| | - Alejandra Bosco
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah, USA
| | - Pablo H Sande
- Laboratory of Retinal Neurochemistry and Experimental Ophthalmology, Department of Human Biochemistry, School of Medicine/CEFyBO, University of Buenos Aires/CONICET, Buenos Aires, Argentina
| | - Ruth E Rosenstein
- Laboratory of Retinal Neurochemistry and Experimental Ophthalmology, Department of Human Biochemistry, School of Medicine/CEFyBO, University of Buenos Aires/CONICET, Buenos Aires, Argentina
| | - Damián Dorfman
- Laboratory of Retinal Neurochemistry and Experimental Ophthalmology, Department of Human Biochemistry, School of Medicine/CEFyBO, University of Buenos Aires/CONICET, Buenos Aires, Argentina
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31
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Midgett DE, Pease ME, Jefferys JL, Patel M, Franck C, Quigley HA, Nguyen TD. The pressure-induced deformation response of the human lamina cribrosa: Analysis of regional variations. Acta Biomater 2017; 53:123-139. [PMID: 28108378 PMCID: PMC6053916 DOI: 10.1016/j.actbio.2016.12.054] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 12/29/2016] [Accepted: 12/31/2016] [Indexed: 01/20/2023]
Abstract
The objective of this study was to measure the pressure-induced deformation response of the human lamina cribrosa (LC) and analyze for variations with age and anatomical region. The posterior scleral cup of 8 eyes from 6 human donors was mounted onto a custom inflation chamber. A laser-scanning microscope was used for second harmonic generation (SHG) imaging of the collagen structure in the posterior volume of the LC at pressures from 5mmHg to 45mmHg. The SHG volumes were analyzed by the Fast-Fourier Iterative Digital Volume Correlation (DVC) algorithm for the three dimensional (3D) displacement field. The components of the Green-Lagrange strain tensor and the in-plane principal and maximum shear strains were evaluated from the DVC displacement field for the central and peripheral regions of the LC and the nasal, temporal, inferior, and superior quadrants surrounding the central retinal artery and vein. Among the major findings were that older age was associated with lower strains, the maximum shear strain was larger in the peripheral than central region, and the maximum principal strain was lower in the nasal quadrant. The elliptical shape of the LC was also predictive of the biaxial strain ratio. Age-related and structure-related variations in the pressure-induced strains of the LC may contribute to the susceptibility and severity of optic nerve damage in glaucoma, and regional variations may explain the progression of axonal damage and tissue remodeling observed in the LC in glaucoma. STATEMENT OF SIGNIFICANCE Glaucoma causes vision loss through progressive damage of the retinal ganglion axons at the lamina cribrosa (LC), the connective tissue structure that supports the axons as they leave the eye. Mechanical characterization of the LC is challenging because of the complex 3D shape and inaccessibility of the tissue. We present a new method using digital volume correlation to map the 3D displacement and strain fields in the LC under inflation. We report for the first time significant regional variations in the strains that are consistent with the pattern of optic nerve damage in early glaucoma. Thus regional strain variations may be predictive of the progression of axonal damage in glaucoma.
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Affiliation(s)
- Dan E Midgett
- Department of Mechanical Engineering, The Johns Hopkins University, Baltimore, MD 21218, USA
| | - Mary E Pease
- Wilmer Ophthalmological Institute, School of Medicine, The Johns Hopkins University, Baltimore, MD 21287, USA
| | - Joan L Jefferys
- Wilmer Ophthalmological Institute, School of Medicine, The Johns Hopkins University, Baltimore, MD 21287, USA
| | - Mohak Patel
- School of Engineering, Brown University, Providence, RI 02912, USA
| | - Christian Franck
- School of Engineering, Brown University, Providence, RI 02912, USA
| | - Harry A Quigley
- Wilmer Ophthalmological Institute, School of Medicine, The Johns Hopkins University, Baltimore, MD 21287, USA
| | - Thao D Nguyen
- Department of Mechanical Engineering, The Johns Hopkins University, Baltimore, MD 21218, USA; Department of Materials Science, The Johns Hopkins University, Baltimore, MD 21218, USA.
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32
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Cerebrospinal Fluid Pressure and Glaucoma. CURRENT OPHTHALMOLOGY REPORTS 2016. [DOI: 10.1007/s40135-016-0110-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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33
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Zhang Z, Wu S, Jonas JB, Zhang J, Liu K, Lu Q, Wang N. Dynein, kinesin and morphological changes in optic nerve axons in a rat model with cerebrospinal fluid pressure reduction: the Beijing Intracranial and Intraocular Pressure (iCOP) study. Acta Ophthalmol 2016; 94:266-75. [PMID: 26178710 DOI: 10.1111/aos.12768] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 03/21/2015] [Accepted: 04/19/2015] [Indexed: 12/11/2022]
Abstract
PURPOSE To examine the influence of experimentally reduced cerebrospinal fluid pressure (CSFP) as compared to elevated intraocular pressure (IOP) on axonal morphology and axonal motor proteins in retinal ganglion cells (RGCs). METHODS The experimental study included 39 rats which underwent cerebrospinal fluid drainage for 6 hr, 30 rats which unilaterally underwent IOP elevation for 6 hr and 30 rats in a control group. Six hours after baseline, the animals were killed and the eyes were histologically and immunohistochemically examined. RESULTS In experimental models in the high-IOP group and the low-CSFP group as compared to the control group, RGC axons became abnormally dilated and accumulated vesicles. Both groups as compared to the control group showed an accumulation of dynein IC (intermediate chain) at the optic nerve head and retina and a reduction in kinesin HC (heavy chain) immunoreactivity in the optic nerve fibre axons. As a corollary, Western blot analysis revealed an elevation of dynein IC protein levels in the optic nerve head and retina and a decrease in kinesin HC protein levels in the optic nerve. CONCLUSIONS Experimental models with an acute IOP rise or with an acute CSFP reduction showed similar morphologic changes in the retinal ganglion cell axons and similar immunohistochemical changes in the axonal motor proteins kinesin HC and dynein IC. It supports the hypothesis that an experimental model with an acute reduction in CSFP as well as an experimental model with an acute rise in IOP may share similarities in the process of optic nerve damage.
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Affiliation(s)
- Zheng Zhang
- Beijing Ophthalmology and Visual Sciences Key Laboratory; Beijing Tongren Eye Center; Beijing Tongren Hospital; Capital Medical University; Beijing China
- Beijing Institute of Ophthalmology; Beijing Tongren Hospital; Capital Medical University; Beijing China
| | - Shen Wu
- Beijing Ophthalmology and Visual Sciences Key Laboratory; Beijing Tongren Eye Center; Beijing Tongren Hospital; Capital Medical University; Beijing China
| | - Jost B. Jonas
- Beijing Institute of Ophthalmology; Beijing Tongren Hospital; Capital Medical University; Beijing China
- Department of Ophthalmology; Medical Faculty Mannheim of the Ruprecht-Karls-University Heidelberg; Mannheim Germany
| | - Jingxue Zhang
- Beijing Ophthalmology and Visual Sciences Key Laboratory; Beijing Tongren Eye Center; Beijing Tongren Hospital; Capital Medical University; Beijing China
| | - Kegao Liu
- Beijing Ophthalmology and Visual Sciences Key Laboratory; Beijing Tongren Eye Center; Beijing Tongren Hospital; Capital Medical University; Beijing China
| | - Qingjun Lu
- Beijing Ophthalmology and Visual Sciences Key Laboratory; Beijing Tongren Eye Center; Beijing Tongren Hospital; Capital Medical University; Beijing China
- Beijing Institute of Ophthalmology; Beijing Tongren Hospital; Capital Medical University; Beijing China
| | - Ningli Wang
- Beijing Ophthalmology and Visual Sciences Key Laboratory; Beijing Tongren Eye Center; Beijing Tongren Hospital; Capital Medical University; Beijing China
- Beijing Institute of Ophthalmology; Beijing Tongren Hospital; Capital Medical University; Beijing China
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De Groef L, Dekeyster E, Geeraerts E, Lefevere E, Stalmans I, Salinas-Navarro M, Moons L. Differential visual system organization and susceptibility to experimental models of optic neuropathies in three commonly used mouse strains. Exp Eye Res 2016; 145:235-247. [PMID: 26791081 DOI: 10.1016/j.exer.2016.01.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 12/16/2015] [Accepted: 01/07/2016] [Indexed: 01/06/2023]
Abstract
Mouse disease models have proven indispensable in glaucoma research, yet the complexity of the vast number of models and mouse strains has also led to confusing findings. In this study, we evaluated baseline intraocular pressure, retinal histology, and retinofugal projections in three mouse strains commonly used in glaucoma research, i.e. C57Bl/6, C57Bl/6-Tyr(c), and CD-1 mice. We found that the mouse strains under study do not only display moderate variations in their intraocular pressure, retinal architecture, and retinal ganglion cell density, also the retinofugal projections to the dorsal lateral geniculate nucleus and the superior colliculus revealed striking differences, potentially underlying diverging optokinetic tracking responses and visual acuity. Next, we reviewed the success rate of three models of (glaucomatous) optic neuropathies (intravitreal N-methyl-d-aspartic acid injection, optic nerve crush, and laser photocoagulation-induced ocular hypertension), looking for differences in disease susceptibility between these mouse strains. Different genetic backgrounds and albinism led to differential susceptibility to experimentally induced retinal ganglion cell death among these three mouse strains. Overall, CD-1 mice appeared to have the highest sensitivity to retinal ganglion cell damage, while the C57Bl/6 background was more resistant in the three models used.
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Affiliation(s)
- Lies De Groef
- Neural Circuit Development and Regeneration Research Group, Animal Physiology and Neurobiology Section, Department of Biology, KU Leuven, Leuven, Belgium
| | - Eline Dekeyster
- Neural Circuit Development and Regeneration Research Group, Animal Physiology and Neurobiology Section, Department of Biology, KU Leuven, Leuven, Belgium
| | - Emiel Geeraerts
- Neural Circuit Development and Regeneration Research Group, Animal Physiology and Neurobiology Section, Department of Biology, KU Leuven, Leuven, Belgium
| | - Evy Lefevere
- Neural Circuit Development and Regeneration Research Group, Animal Physiology and Neurobiology Section, Department of Biology, KU Leuven, Leuven, Belgium
| | - Ingeborg Stalmans
- Laboratory of Ophthalmology, Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Manuel Salinas-Navarro
- Neural Circuit Development and Regeneration Research Group, Animal Physiology and Neurobiology Section, Department of Biology, KU Leuven, Leuven, Belgium
| | - Lieve Moons
- Neural Circuit Development and Regeneration Research Group, Animal Physiology and Neurobiology Section, Department of Biology, KU Leuven, Leuven, Belgium.
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35
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Nguyen TD, Ethier CR. Biomechanical assessment in models of glaucomatous optic neuropathy. Exp Eye Res 2015; 141:125-38. [PMID: 26115620 PMCID: PMC4628840 DOI: 10.1016/j.exer.2015.05.024] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 05/20/2015] [Accepted: 05/31/2015] [Indexed: 01/26/2023]
Abstract
The biomechanical environment within the eye is of interest in both the regulation of intraocular pressure and the loss of retinal ganglion cell axons in glaucomatous optic neuropathy. Unfortunately, this environment is complex and difficult to determine. Here we provide a brief introduction to basic concepts of mechanics (stress, strain, constitutive relationships) as applied to the eye, and then describe a variety of experimental and computational approaches used to study ocular biomechanics. These include finite element modeling, direct experimental measurements of tissue displacements using optical and other techniques, direct experimental measurement of tissue microstructure, and combinations thereof. Thanks to notable technical and conceptual advances in all of these areas, we are slowly gaining a better understanding of how tissue biomechanical properties in both the anterior and posterior segments may influence the development of, and risk for, glaucomatous optic neuropathy. Although many challenging research questions remain unanswered, the potential of this body of work is exciting; projects underway include the coupling of clinical imaging with biomechanical modeling to create new diagnostic tools, development of IOP control strategies based on improved understanding the mechanobiology of the outflow tract, and attempts to develop novel biomechanically-based therapeutic strategies for preservation of vision in glaucoma.
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Affiliation(s)
- Thao D Nguyen
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - C Ross Ethier
- Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, USA; Department of Mechanical Engineering, Georgia Institute of Technology, USA; Institute of Biosciences and Bioengineering, Georgia Institute of Technology, USA; Department of Ophthalmology, Emory University, USA.
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36
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Adalbert R, Coleman MP. Review: Axon pathology in age-related neurodegenerative disorders. Neuropathol Appl Neurobiol 2015; 39:90-108. [PMID: 23046254 DOI: 10.1111/j.1365-2990.2012.01308.x] [Citation(s) in RCA: 121] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2012] [Accepted: 09/24/2012] [Indexed: 12/12/2022]
Abstract
'Dying back' axon degeneration is a prominent feature of many age-related neurodegenerative disorders and is widespread in normal ageing. Although the mechanisms of disease- and age-related losses may differ, both contribute to symptoms. Here, we review recent advances in understanding axon pathology in age-related neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis and glaucoma. In particular, we highlight the importance of axonal transport, autophagy, traumatic brain injury and mitochondrial quality control. We then place these disease mechanisms in the context of changes to axons and dendrites that occur during normal ageing. We discuss what makes ageing such an important risk factor for many neurodegenerative disorders and conclude that the processes of normal ageing and disease combine at the molecular, cellular or systems levels in a range of disorders to produce symptoms. Pathology identical to disease also occurs at the cellular level in most elderly individuals. Thus, normal ageing and age-related disease are inextricably linked and the term 'healthy ageing' downplays the important contributions of cellular pathology. For a full understanding of normal ageing or age-related disease we must study both processes.
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Affiliation(s)
- R Adalbert
- Signalling Programme, The Babraham Institute, Babraham, Cambridge, UK
| | - M P Coleman
- Signalling Programme, The Babraham Institute, Babraham, Cambridge, UK
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37
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Pearson C, Martin K. Stem cell approaches to glaucoma: from aqueous outflow modulation to retinal neuroprotection. PROGRESS IN BRAIN RESEARCH 2015; 220:241-56. [PMID: 26497794 DOI: 10.1016/bs.pbr.2015.04.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Long-term pharmacological management of glaucoma currently relies on self-administered drugs to regulate intraocular pressure (IOP). A number of approaches using stem cells have recently shown promise as potential future treatment strategies complementary to IOP lowering. Several sources of endogenous stem cells have been identified in the eye, some of which may be able to repair the damaged trabecular meshwork and restore functional regulation of aqueous outflow. Neural and mesenchymal stem cells secrete growth factors which provide neuroprotective effects, reducing loss of retinal ganglion cells (RGCs) in animal models. In the future, stem cells may even replace RGCs to reform functional connections between the eye and the brain, although the complexity of such a repair task is formidable. With advances in biomaterial cell scaffolds and concurrent efforts in other neural systems, stem cell therapies are becoming a realistic option for treating multiple eye diseases, and despite ongoing challenges, there are reasons for optimism that stem cells may play a role in the treatment of human glaucoma in the future.
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Affiliation(s)
- Craig Pearson
- John van Geest Centre for Brain Repair, University of Cambridge, Cambridge, UK; Cambridge NIHR Biomedical Research Centre, Cambridge, UK; National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Keith Martin
- John van Geest Centre for Brain Repair, University of Cambridge, Cambridge, UK; Cambridge NIHR Biomedical Research Centre, Cambridge, UK; Wellcome Trust Medical Research Council Cambridge Stem Cell Institute, Cambridge, UK.
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38
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Vidal-Sanz M, Valiente-Soriano FJ, Ortín-Martínez A, Nadal-Nicolás FM, Jiménez-López M, Salinas-Navarro M, Alarcón-Martínez L, García-Ayuso D, Avilés-Trigueros M, Agudo-Barriuso M, Villegas-Pérez MP. Retinal neurodegeneration in experimental glaucoma. PROGRESS IN BRAIN RESEARCH 2015; 220:1-35. [PMID: 26497783 DOI: 10.1016/bs.pbr.2015.04.008] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In rats and mice, limbar tissues of the left eye were laser-photocoagulated (LP) and ocular hypertension (OHT) effects were investigated 1 week to 6 months later. To investigate the innermost layers, retinas were examined in wholemounts using tracing from the superior colliculi to identify retinal ganglion cells (RGCs) with intact retrograde axonal transport, melanopsin immunodetection to identify intrinsically photosensitive RGCs (m(+)RGC), Brn3a immunodetection to identify most RGCs but not m(+)RGCs, RECA1 immunodetection to examine the inner retinal vessels, and DAPI staining to detect all nuclei in the GC layer. The outer retinal layers (ORLs) were examined in cross sections analyzed morphometrically or in wholemounts to study S- and L-cones. Innervation of the superior colliculi was examined 10 days to 14 weeks after LP with orthogradely transported cholera toxin subunit B. By 2 weeks, OHT resulted in pie-shaped sectors devoid of FG(+)RGCs or Brn3a(+)RGCs but with large numbers of DAPI(+)nuclei. Brn3a(+)RGCs were significantly greater than FG(+)RGCs, indicating the survival of large numbers of RGCs with their axonal transport impaired. The inner retinal vasculature showed no abnormalities that could account for the sectorial loss of RGCs. m(+)RGCs decreased to approximately 50-51% in a diffuse loss across the retina. Cross sections showed focal areas of degeneration in the ORLs. RGC loss at 1m diminished to 20-25% and did not progress further with time, whereas the S- and L-cone populations diminished progressively up to 6m. The retinotectal projection was reduced by 10 days and did not progress further. LP-induced OHT results in retrograde degeneration of RGCs and m(+)RGCs, severe damage to the ORL, and loss of retinotectal terminals.
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Affiliation(s)
- Manuel Vidal-Sanz
- Departamento de Oftalmología, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain.
| | - Francisco J Valiente-Soriano
- Departamento de Oftalmología, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
| | - Arturo Ortín-Martínez
- Departamento de Oftalmología, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
| | - Francisco M Nadal-Nicolás
- Departamento de Oftalmología, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
| | - Manuel Jiménez-López
- Departamento de Oftalmología, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
| | - Manuel Salinas-Navarro
- Departamento de Oftalmología, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
| | - Luis Alarcón-Martínez
- Departamento de Oftalmología, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
| | - Diego García-Ayuso
- Departamento de Oftalmología, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
| | - Marcelino Avilés-Trigueros
- Departamento de Oftalmología, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
| | - Marta Agudo-Barriuso
- Departamento de Oftalmología, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
| | - Maria P Villegas-Pérez
- Departamento de Oftalmología, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
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Abstract
Glaucoma is increasingly recognized as a neurodegenerative disorder, characterized by the accelerated loss of retinal ganglion cells (RGCs) and their axons. Impaired axonal transport has been implicated as a pathogenic mechanism in a number of neurodegenerative diseases, including glaucoma. The long RGC axon, with its high metabolic demand and crucial role in conveying neurotrophic signals, relies heavily on intact axonal transport. In this mini review, we consider the evidence for transport disruption along RGCs in association with glaucoma and other intraocular pressure models. We give a brief overview of the axonal transport process and the methods by which it is assessed. Spatial and temporal patterns of axonal transport disruption are considered as well as the reversibility of these changes. Biomechanical, metabolic and cytoskeletal insults may underlie the development of axonal transport deficits, and there are multiple perspectives on the impact that transport disruption has on the RGC. Eliciting the role of impaired axonal transport in glaucoma pathogenesis may uncover novel therapeutic targets for protecting the optic nerve and preventing vision loss in glaucoma.
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Affiliation(s)
- Eamonn T Fahy
- a Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, University of Melbourne , Melbourne , Victoria , Australia
| | - Vicki Chrysostomou
- a Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, University of Melbourne , Melbourne , Victoria , Australia
| | - Jonathan G Crowston
- a Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, University of Melbourne , Melbourne , Victoria , Australia
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40
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Nuschke AC, Farrell SR, Levesque JM, Chauhan BC. Assessment of retinal ganglion cell damage in glaucomatous optic neuropathy: Axon transport, injury and soma loss. Exp Eye Res 2015; 141:111-24. [PMID: 26070986 DOI: 10.1016/j.exer.2015.06.006] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 06/01/2015] [Accepted: 06/06/2015] [Indexed: 02/07/2023]
Abstract
Glaucoma is a disease characterized by progressive axonal pathology and death of retinal ganglion cells (RGCs), which causes structural changes in the optic nerve head and irreversible vision loss. Several experimental models of glaucomatous optic neuropathy (GON) have been developed, primarily in non-human primates and, more recently and commonly, in rodents. These models provide important research tools to study the mechanisms underlying glaucomatous damage. Moreover, experimental GON provides the ability to quantify and monitor risk factors leading to RGC loss such as the level of intraocular pressure, axonal health and the RGC population. Using these experimental models we are able to gain a better understanding of GON, which allows for the development of potential neuroprotective strategies. Here we review the advantages and disadvantages of the relevant and most often utilized methods for evaluating axonal degeneration and RGC loss in GON. Axonal pathology in GON includes functional disruption of axonal transport (AT) and structural degeneration. Horseradish peroxidase (HRP), rhodamine-B-isothiocyanate (RITC) and cholera toxin-B (CTB) fluorescent conjugates have proven to be effective reporters of AT. Also, immunohistochemistry (IHC) for endogenous AT-associated proteins is often used as an indicator of AT function. Similarly, structural degeneration of axons in GON can be investigated via changes in the activity and expression of key axonal enzymes and structural proteins. Assessment of axonal degeneration can be measured by direct quantification of axons, qualitative grading, or a combination of both methods. RGC loss is the most frequently quantified variable in studies of experimental GON. Retrograde tracers can be used to quantify RGC populations in rodents via application to the superior colliculus (SC). In addition, in situ IHC for RGC-specific proteins is a common method of RGC quantification used in many studies. Recently, transgenic mouse models that express fluorescent proteins under the Thy-1 promoter have been examined for their potential to provide specific and selective labeling of RGCs for the study of GON. While these methods represent important advances in assessing the structural and functional integrity of RGCs, each has its advantages and disadvantages; together they provide an extensive toolbox for the study of GON.
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Affiliation(s)
- Andrea C Nuschke
- Retina and Optic Nerve Research Laboratory, Dalhousie University, Halifax, Nova Scotia, Canada; Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Spring R Farrell
- Retina and Optic Nerve Research Laboratory, Dalhousie University, Halifax, Nova Scotia, Canada; Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada; Capital District Health Authority, Halifax, Nova Scotia, Canada
| | - Julie M Levesque
- Retina and Optic Nerve Research Laboratory, Dalhousie University, Halifax, Nova Scotia, Canada; Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Balwantray C Chauhan
- Retina and Optic Nerve Research Laboratory, Dalhousie University, Halifax, Nova Scotia, Canada; Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada; Capital District Health Authority, Halifax, Nova Scotia, Canada; Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, Nova Scotia, Canada.
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41
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Fortune B. In vivo imaging methods to assess glaucomatous optic neuropathy. Exp Eye Res 2015; 141:139-53. [PMID: 26048475 DOI: 10.1016/j.exer.2015.06.001] [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: 03/08/2015] [Revised: 05/13/2015] [Accepted: 06/01/2015] [Indexed: 10/23/2022]
Abstract
The goal of this review is to summarize the most common imaging methods currently applied for in vivo assessment of ocular structure in animal models of experimental glaucoma with an emphasis on translational relevance to clinical studies of the human disease. The most common techniques in current use include optical coherence tomography and scanning laser ophthalmoscopy. In reviewing the application of these and other imaging modalities to study glaucomatous optic neuropathy, this article is organized into three major sections: 1) imaging the optic nerve head, 2) imaging the retinal nerve fiber layer and 3) imaging retinal ganglion cell soma and dendrites. The article concludes with a brief section on possible future directions.
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Affiliation(s)
- Brad Fortune
- Discoveries in Sight Research Laboratories, Devers Eye Institute and Legacy Research Institute, Legacy Health, 1225 NE Second Avenue, Portland, OR 97232, USA.
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42
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Emre E, Yüksel N, Duruksu G, Pirhan D, Subaşi C, Erman G, Karaöz E. Neuroprotective effects of intravitreally transplanted adipose tissue and bone marrow-derived mesenchymal stem cells in an experimental ocular hypertension model. Cytotherapy 2015; 17:543-59. [PMID: 25618560 DOI: 10.1016/j.jcyt.2014.12.005] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 12/05/2014] [Accepted: 12/05/2014] [Indexed: 12/17/2022]
Abstract
BACKGROUND AIMS The purpose of this study was to investigate the neuroprotective effects of bone marrow bone marrow-derived and adipose tissue-derived mesenchymal stromal cells (MSCs) that were intravitreally transplanted in an experimental ocular hypertension (OHT) model. METHODS An OHT rat model was generated by means of intracameral injection of hyaluronic acid into the anterior chamber. MSCs labeled with green fluorescence protein were transplanted intravitreally 1 week after OHT induction. At the end of the second and fourth weeks, retinal ganglion cells were visualized with the use of a flat-mount retina method and were evaluated by means of immunofluorescence staining against green fluorescence protein, vimentin, CD105, and cytokines (interleukin [IL]-1Ra, prostaglandin E2 receptor, IL-6, transforming growth factor-β1, interferon-γ and tumor necrosis factor-α). RESULTS The retinal ganglion cell numbers per area were significantly improved in stem cell-treated OHT groups compared with that in the non-treated OHT group (P < 0.05). The results of immunohistochemical analyses indicated that a limited number of stem cells had integrated into the ganglion cell layer and the inner nuclear layer. The number of cells expressing proinflammatory cytokines (interferon-γ and tumor necrosis factor-α) decreased in the MSC-transferred group compared with that in the OHT group after 4 weeks (P < 0.01). On the other hand, IL-1Ra and prostaglandin E2 receptor expressions were increased in the rat bone marrow-derived MSC group but were more significant in the rat adipose tissue-derived MSC group (P < 0.01). CONCLUSIONS After intravitreal transplantation, MSCs showed a neuroprotective effect in the rat OHT model. Therefore, MSCs promise an alternative therapy approach for functional recovery in the treatment of glaucoma.
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Affiliation(s)
- Esra Emre
- Department of Ophthalmology, Çerkezköy State Hospital, Tekirdağ, Turkey.
| | - Nurşen Yüksel
- Department of Ophthalmology, School of Medicine, Kocaeli University, Kocaeli, Turkey
| | - Gökhan Duruksu
- Center for Stem Cell and Gene Therapies Research and Practice, Kocaeli University, Kocaeli, Turkey
| | - Dilara Pirhan
- Department of Ophthalmology, School of Medicine, Kocaeli University, Kocaeli, Turkey
| | - Cansu Subaşi
- Liv Hospital, Center for Regenerative Medicine and Stem Cell Research & Manufacturing (Liv MedCell) Istanbul, Turkey
| | - Gülay Erman
- Center for Stem Cell and Gene Therapies Research and Practice, Kocaeli University, Kocaeli, Turkey
| | - Erdal Karaöz
- Liv Hospital, Center for Regenerative Medicine and Stem Cell Research & Manufacturing (Liv MedCell) Istanbul, Turkey
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43
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Stankowska DL, Minton AZ, Rutledge MA, Mueller BH, Phatak NR, He S, Ma HY, Forster MJ, Yorio T, Krishnamoorthy RR. Neuroprotective effects of transcription factor Brn3b in an ocular hypertension rat model of glaucoma. Invest Ophthalmol Vis Sci 2015; 56:893-907. [PMID: 25587060 DOI: 10.1167/iovs.14-15008] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
PURPOSE Glaucoma is an optic neuropathy commonly associated with elevated intraocular pressure (IOP), leading to optic nerve head (ONH) cupping, axon loss, and apoptosis of retinal ganglion cells (RGCs), which could ultimately result in blindness. Brn3b is a class-4 POU domain transcription factor that plays a key role in RGC development, axon outgrowth, and pathfinding. Previous studies suggest that a decrease in Brn3b levels occurs in animal models of glaucoma. The goal of this study was to determine if adeno-associated virus (AAV)-directed overexpression of the Brn3b protein could have neuroprotective effects following elevated IOP-mediated neurodegeneration. METHODS Intraocular pressure was elevated in one eye of Brown Norway rats (Rattus norvegicus), following which the IOP-elevated eyes were intravitreally injected with AAV constructs encoding either the GFP (rAAV-CMV-GFP and rAAV-hsyn-GFP) or Brn3b (rAAV-CMV-Brn3b and rAAV-hsyn-Brn3b). Retina sections through the ONH were stained for synaptic plasticity markers and neuroprotection was assessed by RGC counts and visual acuity tests. RESULTS Adeno-associated virus-mediated expression of the Brn3b protein in IOP-elevated rat eyes promoted an upregulation of growth associated protein-43 (GAP-43), actin binding LIM protein (abLIM) and acetylated α-tubulin (ac-Tuba) both posterior to the ONH and in RGCs. The RGC survival as well as axon integrity score were significantly improved in IOP-elevated rAAV-hsyn-Brn3b-injected rats compared with those of the IOP-elevated rAAV-hsyn-GFP- injected rats. Additionally, intravitreal rAAV-hsyn-Brn3b administration significantly restored the visual optomotor response in IOP-elevated rat eyes. CONCLUSIONS Adeno-associated virus-mediated Brn3b protein expression may be a suitable approach for promoting neuroprotection in animal models of glaucoma.
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Affiliation(s)
- Dorota L Stankowska
- University of North Texas Health Science Center, Department of Cell Biology and Immunology, North Texas Eye Research Institute, Fort Worth, Texas, United States
| | - Alena Z Minton
- University of North Texas Health Science Center, Department of Cell Biology and Immunology, North Texas Eye Research Institute, Fort Worth, Texas, United States
| | - Margaret A Rutledge
- University of North Texas Health Science Center, Department of Pharmacology & Neuroscience, Fort Worth, Texas, United States
| | - Brett H Mueller
- University of North Texas Health Science Center, Department of Pharmacology & Neuroscience, Fort Worth, Texas, United States
| | - Nitasha R Phatak
- University of North Texas Health Science Center, Department of Cell Biology and Immunology, North Texas Eye Research Institute, Fort Worth, Texas, United States
| | - Shaoqing He
- University of North Texas Health Science Center, Department of Cell Biology and Immunology, North Texas Eye Research Institute, Fort Worth, Texas, United States
| | - Hai-Ying Ma
- University of North Texas Health Science Center, Department of Pharmacology & Neuroscience, Fort Worth, Texas, United States
| | - Michael J Forster
- University of North Texas Health Science Center, Department of Pharmacology & Neuroscience, Fort Worth, Texas, United States
| | - Thomas Yorio
- University of North Texas Health Science Center, Department of Pharmacology & Neuroscience, Fort Worth, Texas, United States
| | - Raghu R Krishnamoorthy
- University of North Texas Health Science Center, Department of Cell Biology and Immunology, North Texas Eye Research Institute, Fort Worth, Texas, United States
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44
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Wong M, Li Y, Li S, Zhang S, Li W, Zhang P, Chen C, Barnstable CJ, Zhang SS, Zhang C, Huang P. Therapeutic Retrobulbar Inhibition of STAT3 Protects Ischemic Retina Ganglion Cells. Mol Neurobiol 2014; 52:1364-1377. [DOI: 10.1007/s12035-014-8945-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 10/16/2014] [Indexed: 12/14/2022]
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45
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Baptista FI, Pinto MJ, Elvas F, Martins T, Almeida RD, Ambrósio AF. Diabetes induces changes in KIF1A, KIF5B and dynein distribution in the rat retina: implications for axonal transport. Exp Eye Res 2014; 127:91-103. [PMID: 25064602 DOI: 10.1016/j.exer.2014.07.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Revised: 07/14/2014] [Accepted: 07/15/2014] [Indexed: 10/25/2022]
Abstract
Diabetic retinopathy is a leading cause of vision loss and blindness. Disruption of axonal transport is associated with many neurodegenerative diseases and might also play a role in diabetes-associated disorders affecting nervous system. We investigated the impact of type 1 diabetes (2 and 8 weeks duration) on KIF1A, KIF5B and dynein motor proteins in the retina. Additionally, since hyperglycemia is considered the main trigger of diabetic complications, we investigated whether prolonged exposure to elevated glucose could affect the content and distribution of motor proteins in retinal cultures. The immunoreactivity of motor proteins was evaluated by immunohistochemistry in retinal sections and by immunoblotting in total retinal extracts from streptozotocin-induced diabetic and age-matched control animals. Primary retinal cultures were exposed to high glucose (30 mM) or mannitol (osmotic control; 24.5 mM plus 5.5 mM glucose), for seven days. Diabetes decreased the content of KIF1A at 8 weeks of diabetes as well as KIF1A immunoreactivity in the majority of retinal layers, except for the photoreceptor and outer nuclear layer. Changes in KIF5B immunoreactivity were also detected by immunohistochemistry in the retina at 8 weeks of diabetes, being increased at the photoreceptor and outer nuclear layer, and decreased in the ganglion cell layer. Regarding dynein immunoreactivity there was an increase in the ganglion cell layer after 8 weeks of diabetes. No changes were detected in retinal cultures. These alterations suggest that axonal transport may be impaired under diabetes, which might contribute to early signs of neural dysfunction in the retina of diabetic patients and animal models.
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Affiliation(s)
- Filipa I Baptista
- Centre of Ophthalmology and Vision Sciences, IBILI, Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal; Pharmacology and Experimental Therapeutics, IBILI, Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal
| | - Maria J Pinto
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal; PhD Programme in Experimental Biology and Biomedicine (PDBEB), Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal
| | - Filipe Elvas
- Centre of Ophthalmology and Vision Sciences, IBILI, Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal; Pharmacology and Experimental Therapeutics, IBILI, Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal
| | - Tiago Martins
- Centre of Ophthalmology and Vision Sciences, IBILI, Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal; Pharmacology and Experimental Therapeutics, IBILI, Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal
| | - Ramiro D Almeida
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal
| | - António F Ambrósio
- Centre of Ophthalmology and Vision Sciences, IBILI, Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal; Pharmacology and Experimental Therapeutics, IBILI, Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal; CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal; AIBILI, 3004-548 Coimbra, Portugal.
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Abbott CJ, Choe TE, Lusardi TA, Burgoyne CF, Wang L, Fortune B. Evaluation of retinal nerve fiber layer thickness and axonal transport 1 and 2 weeks after 8 hours of acute intraocular pressure elevation in rats. Invest Ophthalmol Vis Sci 2014; 55:674-87. [PMID: 24398096 DOI: 10.1167/iovs.13-12811] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
PURPOSE To compare in vivo retinal nerve fiber layer thickness (RNFLT) and axonal transport at 1 and 2 weeks after an 8-hour acute IOP elevation in rats. METHODS Forty-seven adult male Brown Norway rats were used. Procedures were performed under anesthesia. The IOP was manometrically elevated to 50 mm Hg or held at 15 mm Hg (sham) for 8 hours unilaterally. The RNFLT was measured by spectral-domain optical coherence tomography. Anterograde and retrograde axonal transport was assessed from confocal scanning laser ophthalmoscopy imaging 24 hours after bilateral injections of 2 μL 1% cholera toxin B-subunit conjugated to AlexaFluor 488 into the vitreous or superior colliculi, respectively. Retinal ganglion cell (RGC) and microglial densities were determined using antibodies against Brn3a and Iba-1. RESULTS The RNFLT in experimental eyes increased from baseline by 11% at 1 day (P < 0.001), peaked at 19% at 1 week (P < 0.0001), remained 11% thicker at 2 weeks (P < 0.001), recovered at 3 weeks (P > 0.05), and showed no sign of thinning at 6 weeks (P > 0.05). There was no disruption of anterograde transport at 1 week (superior colliculi fluorescence intensity, 75.3 ± 7.9 arbitrary units [AU] for the experimental eyes and 77.1 ± 6.7 AU for the control eyes) (P = 0.438) or 2 weeks (P = 0.188). There was no obstruction of retrograde transport at 1 week (RCG density, 1651 ± 153 per mm(2) for the experimental eyes and 1615 ± 135 per mm(2) for the control eyes) (P = 0.63) or 2 weeks (P = 0.25). There was no loss of Brn3a-positive RGC density at 6 weeks (P = 0.74) and no increase in microglial density (P = 0.92). CONCLUSIONS Acute IOP elevation to 50 mm Hg for 8 hours does not cause a persisting axonal transport deficit at 1 or 2 weeks or a detectable RNFLT or RGC loss by 6 weeks but does lead to transient RNFL thickening that resolves by 3 weeks.
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Affiliation(s)
- Carla J Abbott
- Discoveries in Sight Research Laboratories, Legacy Good Samaritan Devers Eye Institute, and Legacy Research Institute, Legacy Health, Portland, Oregon
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Johnson TV, Bull ND, Martin KR. Stem cell therapy for glaucoma: possibilities and practicalities. EXPERT REVIEW OF OPHTHALMOLOGY 2014; 6:165-174. [PMID: 21686079 DOI: 10.1586/eop.11.3] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Glaucoma is a progressive, neurodegenerative, optic neuropathy in which currently available therapies cannot always prevent, and do not reverse, vision loss. Stem cell transplantation may provide a promising new avenue for treating many presently incurable degenerative conditions, including glaucoma. This article will explore the various ways in which transplantation of stem or progenitor cells may be applied for the treatment of glaucoma. We will critically discuss the translational prospects of two cell transplantation-based treatment modalities: neuroprotection and retinal ganglion cell replacement. In addition, we will identify specific questions that need to be addressed and obstacles to overcome on the path to clinical translation, and offer insight into potential strategies for approaching this goal.
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Affiliation(s)
- Thomas V Johnson
- Cambridge Centre for Brain Repair, University of Cambridge ED Adrian Building Forvie Site, Robinson Way, Cambridge, CB2 OPY, UK
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Williams PA, Howell GR, Barbay JM, Braine CE, Sousa GL, John SWM, Morgan JE. Retinal ganglion cell dendritic atrophy in DBA/2J glaucoma. PLoS One 2013; 8:e72282. [PMID: 23977271 PMCID: PMC3747092 DOI: 10.1371/journal.pone.0072282] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Accepted: 07/15/2013] [Indexed: 11/18/2022] Open
Abstract
Glaucoma is a complex disease affecting an estimated 70 million people worldwide, characterised by the progressive degeneration of retinal ganglion cells and accompanying visual field loss. The common site of damage to retinal ganglion cells is thought to be at the optic nerve head, however evidence from other optic neuropathies and neurodegenerative disorders suggests that dendritic structures undergo a prolonged period of atrophy that may accompany or even precede soma loss and neuronal cell death. Using the DBA/2J mouse model of glaucoma this investigation aims to elucidate the impact of increasing intraocular pressure on retinal ganglion cell dendrites using DBA/2J mice that express YFP throughout the retinal ganglion cells driven by Thy1 (DBA/2J.Thy1(YFP)) and DiOlistically labelled retinal ganglion cells in DBA/2J mice. Here we show retinal ganglion cell dendritic degeneration in DiOlistically labelled DBA/2J retinal ganglion cells but not in the DBA/2J.Thy1(YFP) retinal ganglion cells suggesting that a potential downregulation of Thy1 allows only ‘healthy’ retinal ganglion cells to express YFP. These data may highlight alternative pathways to retinal ganglion cell loss in DBA/2J glaucoma.
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Affiliation(s)
- Pete A. Williams
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Gareth R. Howell
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | | | | | - Gregory L. Sousa
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Simon W. M. John
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
- The Howard Hughes Medical Institute, Bar Habor, Maine, United States of America
- Department of Ophthalmology, Tufts University of Medicine, Boston, Massachusetts, United States of America
| | - James E. Morgan
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom
- Cardiff Eye Unit, University Hospital of Wales, Cardiff, United Kingdom
- * E-mail:
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Retinal ganglion cells: Energetics, compartmentation, axonal transport, cytoskeletons and vulnerability. Prog Retin Eye Res 2013; 36:217-46. [PMID: 23891817 DOI: 10.1016/j.preteyeres.2013.07.001] [Citation(s) in RCA: 137] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 07/02/2013] [Accepted: 07/02/2013] [Indexed: 11/20/2022]
Abstract
Retinal ganglion cells (RGCs) are specialized projection neurons that relay an immense amount of visual information from the retina to the brain. RGC signal inputs are collected by dendrites and output is distributed from the cell body via very thin (0.5-1 μm) and long (∼50 mm) axons. The RGC cell body is larger than other retinal neurons, but is still only a very small fraction (one ten thousandths) of the length and total surface area of the axon. The total distance traversed by RGCs extends from the retina, starting from synapses with bipolar and amacrine cells, to the brain, to synapses with neurons in the lateral geniculate nucleus. This review will focus on the energy demands of RGCs and the relevant tissues that surround them. RGC survival and function unexceptionally depends upon free energy, predominantly adenosine triphosphate (ATP). RGC energy metabolism is vastly different when compared to that of the photoreceptors. Each subcellular component of the RGC is remarkably different in terms of structure, function and extracellular environment. The energy demands and distribution of each component are also distinct as evidenced by the uneven distribution of mitochondria and ATP within the RGC - signifying the presence of intracellular energy gradients. In this review we will describe RGCs as having four subcellular components, (1) Dendrites, (2) Cell body, (3) Non-myelinated axon, including intraocular and optic nerve head portions, and (4) Myelinated axon, including the intra-orbital and intracranial portions. We will also describe how RGCs integrate information from each subcellular component in order achieve intracellular homeostatic stability as well as respond to perturbations in the extracellular environment. The possible cellular mechanisms such as axonal transport and axonal cytoskeleton proteins that are involved in maintaining RGC energy homeostasis during normal and disease conditions will also be discussed in depth. The emphasis of this review will be on energetic mechanisms within RGC components that have the most relevance to clinical ophthalmology.
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Abstract
Early axon loss is a common feature of many neurodegenerative disorders. It renders neurons functionally inactive, or less active if axon branches are lost, in a manner that is often irreversible. In the CNS, there is no long-range axon regeneration and even peripheral nerve axons are unlikely to reinnervate their targets while the cause of the problem persists. In most disorders, axon degeneration precedes cell death so it is not simply a consequence of it, and it is now clear that axons have at least one degeneration mechanism that differs from that of the soma. It is important to understand these degeneration mechanisms and their contribution to axon loss in neurodegenerative disorders. In this way, it should become possible to prevent axon loss as well as cell death. This special edition considers the roles and mechanisms of axon degeneration in amyotrophic lateral sclerosis, Charcot-Marie-Tooth disease, hereditary spastic paraplegia, ischemic injury, traumatic brain injury, Alzheimer's disease, glaucoma, Huntington's disease and Parkinson's disease. Using examples from these and other disorders, this introduction considers some of the reasons for axon vulnerability. It also illustrates how molecular genetics and studies of Wallerian degeneration have contributed to our understanding of axon degeneration mechanisms.
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