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Lewis LSC, Skiba NP, Hao Y, Bomze HM, Arshavsky VY, Cartoni R, Gospe SM. Compartmental Differences in the Retinal Ganglion Cell Mitochondrial Proteome. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.07.593032. [PMID: 38766051 PMCID: PMC11100734 DOI: 10.1101/2024.05.07.593032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Among neurons, retinal ganglion cells (RGCs) are uniquely sensitive to mitochondrial dysfunction. The RGC is highly polarized, with a somatodendritic compartment in the inner retina and an axonal compartment projecting to targets in the brain. The drastically dissimilar functions of these compartments implies that mitochondria face different bioenergetic and other physiological demands. We hypothesized that compartmental differences in mitochondrial biology would be reflected by disparities in mitochondrial protein composition. Here, we describe a protocol to isolate intact mitochondria separately from mouse RGC somatodendritic and axonal compartments by immunoprecipitating labeled mitochondria from RGC MitoTag mice. Using mass spectrometry, 471 and 357 proteins were identified in RGC somatodendritic and axonal mitochondrial immunoprecipitates, respectively. We identified 10 mitochondrial proteins exclusively in the somatodendritic compartment and 19 enriched ≥2-fold there, while 3 proteins were exclusively identified and 18 enriched in the axonal compartment. Our observation of compartment-specific enrichment of mitochondrial proteins was validated through immunofluorescence analysis of the localization and relative abundance of superoxide dismutase ( SOD2 ), sideroflexin-3 ( SFXN3 ) and trifunctional enzyme subunit alpha ( HADHA ) in retina and optic nerve specimens. The identified compartmental differences in RGC mitochondrial composition may provide promising leads for uncovering physiologically relevant pathways amenable to therapeutic intervention for optic neuropathies.
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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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Zhu J, Chen H, Wu J, Li S, Lin W, Wang N, Bai L. Ferroptosis in Glaucoma: A Promising Avenue for Therapy. Adv Biol (Weinh) 2024; 8:e2300530. [PMID: 38411382 DOI: 10.1002/adbi.202300530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 01/08/2024] [Indexed: 02/28/2024]
Abstract
Glaucoma, a blind-leading disease largely since chronic pathological intraocular high pressure (ph-IOP). Hitherto, it is reckoned incurable for irreversible neural damage and challenges in managing IOP. Thus, it is significant to develop neuroprotective strategies. Ferroptosis, initially identified as an iron-dependent regulated death that triggers Fenton reactions and culminates in lipid peroxidation (LPO), has emerged as a focal point in multiple tumors and neurodegenerative diseases. Researches show that iron homeostasis play critical roles in the optic nerve (ON) and retinal ganglion cells (RGCs), suggesting targeted treatments could be effective. In glaucoma, apart from neural lesions, disrupted metal balance and increased oxidative stress in trabecular meshwork (TM) are observed. These disturbances lead to extracellular matrix excretion disorders, known as sclerotic mechanisms, resulting in refractory blockages. Importantly, oxidative stress, a significant downstream effect of ferroptosis, is also a key factor in cell senescence. It plays a crucial role in both the etiology and risk of glaucoma. Moreover, ferroptosis also induces non-infectious inflammation, which exacerbate glaucomatous injury. Therefore, the relevance of ferroptosis in glaucoma is extensive and multifaceted. In this review, the study delves into the current understanding of ferroptosis mechanisms in glaucoma, aiming to provide clues to inform clinical therapeutic practices.
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Affiliation(s)
- Jingyun Zhu
- Department of Ophthalmology, Nanfang Hospital, Southern Medical University, No.1023-1063, Shatai South Road, Baiyun District, Guangzhou, Guangdong, 510515, China
| | - Hui Chen
- Department of Geriatrics, Hospital of Traditional Chinese Medicine Affiliated to Southwest Medical University, No.182, Chunhui Road, Longmatan District, Luzhou, Sichuan, 646000, China
| | - Jian Wu
- Department of Ophthalmology, Beijing Tongren Hospital, Capital Medical University, No. 8, East Chongwenmennei Street, Dongcheng District, Beijing, 100005, China
| | - Sen Li
- Department of Spinal Surgery, Drum Tower Hospital, Nanjing University, No. 321 Zhongshan Road, Gulou District, Nanjing, Jiangsu, 210008, China
| | - Wanying Lin
- Department of Ophthalmology, Nanfang Hospital, Southern Medical University, No.1023-1063, Shatai South Road, Baiyun District, Guangzhou, Guangdong, 510515, China
| | - Ningli Wang
- Department of Ophthalmology, Beijing Tongren Hospital, Capital Medical University, No. 8, East Chongwenmennei Street, Dongcheng District, Beijing, 100005, China
| | - Lang Bai
- Department of Ophthalmology, Nanfang Hospital, Southern Medical University, No.1023-1063, Shatai South Road, Baiyun District, Guangzhou, Guangdong, 510515, China
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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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Alrobaian M, Alkhuraiji A, Almohanna R, Alshehri M, Alyahya B. Visual outcome of methanol toxic optic neuropathy after erythropoietin treatment in Riyadh, Saudi Arabia. Saudi J Ophthalmol 2024; 38:41-46. [PMID: 38628402 PMCID: PMC11017006 DOI: 10.4103/sjopt.sjopt_174_22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 01/29/2023] [Accepted: 03/07/2023] [Indexed: 04/19/2024] Open
Abstract
PURPOSE The purpose of this study is to evaluate the visual response of methanol-induced optic neuropathy to management with erythropoietin (EPO) along with conventional therapy. METHODS This retrospective case series examines the ophthalmological data of patients diagnosed with methanol-induced optic neuropathy between 2020 and 2021 at two centers, Riyadh, Saudi Arabia. Patients' characteristics and the results of initial and final ophthalmological examinations were documented and compared between patients who received EPO in addition to conventional management and those who received only conventional management. RESULTS A total of nine cases were reviewed, of which eight (88.9%) were males and one was female (11.1%). The mean age was 37.7 years. At presentation, funduscopic examination revealed optic disc edema in four eyes (two patients), and 14 eyes had normal appearance (seven patients). Among the nine patients who received conventional management, 5 (55.6%) additionally received intravenous EPO during the treatment course. There was no clinically or statistically significant difference in terms of visual outcome between the two groups. The mean visual acuity at the final presentation was 1.32 ± 0.79 logarithm of the minimum angle of resolution (LogMAR) in the EPO group and 1.36 ± 0.85 LogMAR in the non-EPO group. Optical coherence tomography indicated that the EPO group had an average retinal nerve fiber layer thickness of 48.13μm (±6.2), at the final assessment. CONCLUSION Managing the visual impairments in individuals with methanol-induced optic neuropathy using intravenous EPO resulted in similar final visual outcomes compared to conventional management.
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Affiliation(s)
- Malek Alrobaian
- Department of Ophthalmology, Ministry of the National Guard – Health Affairs, Riyadh, Saudi Arabia
- King Abdullah International Medical Research Center, Riyadh, Saudi Arabia
| | - Arwa Alkhuraiji
- Department of Ophthalmology, Ministry of the National Guard – Health Affairs, Riyadh, Saudi Arabia
- King Abdullah International Medical Research Center, Riyadh, Saudi Arabia
| | - Rema Almohanna
- King Abdullah International Medical Research Center, Riyadh, Saudi Arabia
- Department of Surgery, Ministry of the National Guard – Health Affairs, Riyadh, Saudi Arabia
| | - Mohammed Alshehri
- Department of Emergency Medicine, King Khalid University Hospital, Riyadh, Saudi Arabia
| | - Bader Alyahya
- Department of Emergency Medicine, College of Medicine, King Saud University, Riyadh, Saudi Arabia
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Wong DCS, Harvey JP, Jurkute N, Thomasy SM, Moosajee M, Yu-Wai-Man P, Gilhooley MJ. OPA1 Dominant Optic Atrophy: Pathogenesis and Therapeutic Targets. J Neuroophthalmol 2023; 43:464-474. [PMID: 37974363 PMCID: PMC10645107 DOI: 10.1097/wno.0000000000001830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2023]
Affiliation(s)
- David C. S. Wong
- Department of Clinical Neurosciences (DCSW, PY-W-M), John van Geest Center for Brain Repair, University of Cambridge, Cambridge, United Kingdom; Cambridge Eye Unit (DCSW, PY-W-M), Addenbrooke's Hospital, Cambridge, United Kingdom; UCL Institute of Ophthalmology (JPH, NJ, MM, PY-W-M, MJG), London, United Kingdom; Moorfields Eye Hospital NHS Foundation Trust (JPH, NJ, MM, PY-W-M, MJG), London, United Kingdom; Department of Ophthalmology and Vision Science (SMT), School of Medicine, U.C. Davis, Sacramento, California; Department of Surgical and Radiological Sciences (SMT), School of Veterinary Medicine, U.C. Davis, California; Great Ormond Street Hospital (MM), London, United Kingdom; and The Francis Crick Institute (MM), London, United Kingdom
| | - Joshua P. Harvey
- Department of Clinical Neurosciences (DCSW, PY-W-M), John van Geest Center for Brain Repair, University of Cambridge, Cambridge, United Kingdom; Cambridge Eye Unit (DCSW, PY-W-M), Addenbrooke's Hospital, Cambridge, United Kingdom; UCL Institute of Ophthalmology (JPH, NJ, MM, PY-W-M, MJG), London, United Kingdom; Moorfields Eye Hospital NHS Foundation Trust (JPH, NJ, MM, PY-W-M, MJG), London, United Kingdom; Department of Ophthalmology and Vision Science (SMT), School of Medicine, U.C. Davis, Sacramento, California; Department of Surgical and Radiological Sciences (SMT), School of Veterinary Medicine, U.C. Davis, California; Great Ormond Street Hospital (MM), London, United Kingdom; and The Francis Crick Institute (MM), London, United Kingdom
| | - Neringa Jurkute
- Department of Clinical Neurosciences (DCSW, PY-W-M), John van Geest Center for Brain Repair, University of Cambridge, Cambridge, United Kingdom; Cambridge Eye Unit (DCSW, PY-W-M), Addenbrooke's Hospital, Cambridge, United Kingdom; UCL Institute of Ophthalmology (JPH, NJ, MM, PY-W-M, MJG), London, United Kingdom; Moorfields Eye Hospital NHS Foundation Trust (JPH, NJ, MM, PY-W-M, MJG), London, United Kingdom; Department of Ophthalmology and Vision Science (SMT), School of Medicine, U.C. Davis, Sacramento, California; Department of Surgical and Radiological Sciences (SMT), School of Veterinary Medicine, U.C. Davis, California; Great Ormond Street Hospital (MM), London, United Kingdom; and The Francis Crick Institute (MM), London, United Kingdom
| | - Sara M. Thomasy
- Department of Clinical Neurosciences (DCSW, PY-W-M), John van Geest Center for Brain Repair, University of Cambridge, Cambridge, United Kingdom; Cambridge Eye Unit (DCSW, PY-W-M), Addenbrooke's Hospital, Cambridge, United Kingdom; UCL Institute of Ophthalmology (JPH, NJ, MM, PY-W-M, MJG), London, United Kingdom; Moorfields Eye Hospital NHS Foundation Trust (JPH, NJ, MM, PY-W-M, MJG), London, United Kingdom; Department of Ophthalmology and Vision Science (SMT), School of Medicine, U.C. Davis, Sacramento, California; Department of Surgical and Radiological Sciences (SMT), School of Veterinary Medicine, U.C. Davis, California; Great Ormond Street Hospital (MM), London, United Kingdom; and The Francis Crick Institute (MM), London, United Kingdom
| | - Mariya Moosajee
- Department of Clinical Neurosciences (DCSW, PY-W-M), John van Geest Center for Brain Repair, University of Cambridge, Cambridge, United Kingdom; Cambridge Eye Unit (DCSW, PY-W-M), Addenbrooke's Hospital, Cambridge, United Kingdom; UCL Institute of Ophthalmology (JPH, NJ, MM, PY-W-M, MJG), London, United Kingdom; Moorfields Eye Hospital NHS Foundation Trust (JPH, NJ, MM, PY-W-M, MJG), London, United Kingdom; Department of Ophthalmology and Vision Science (SMT), School of Medicine, U.C. Davis, Sacramento, California; Department of Surgical and Radiological Sciences (SMT), School of Veterinary Medicine, U.C. Davis, California; Great Ormond Street Hospital (MM), London, United Kingdom; and The Francis Crick Institute (MM), London, United Kingdom
| | - Patrick Yu-Wai-Man
- Department of Clinical Neurosciences (DCSW, PY-W-M), John van Geest Center for Brain Repair, University of Cambridge, Cambridge, United Kingdom; Cambridge Eye Unit (DCSW, PY-W-M), Addenbrooke's Hospital, Cambridge, United Kingdom; UCL Institute of Ophthalmology (JPH, NJ, MM, PY-W-M, MJG), London, United Kingdom; Moorfields Eye Hospital NHS Foundation Trust (JPH, NJ, MM, PY-W-M, MJG), London, United Kingdom; Department of Ophthalmology and Vision Science (SMT), School of Medicine, U.C. Davis, Sacramento, California; Department of Surgical and Radiological Sciences (SMT), School of Veterinary Medicine, U.C. Davis, California; Great Ormond Street Hospital (MM), London, United Kingdom; and The Francis Crick Institute (MM), London, United Kingdom
| | - Michael J. Gilhooley
- Department of Clinical Neurosciences (DCSW, PY-W-M), John van Geest Center for Brain Repair, University of Cambridge, Cambridge, United Kingdom; Cambridge Eye Unit (DCSW, PY-W-M), Addenbrooke's Hospital, Cambridge, United Kingdom; UCL Institute of Ophthalmology (JPH, NJ, MM, PY-W-M, MJG), London, United Kingdom; Moorfields Eye Hospital NHS Foundation Trust (JPH, NJ, MM, PY-W-M, MJG), London, United Kingdom; Department of Ophthalmology and Vision Science (SMT), School of Medicine, U.C. Davis, Sacramento, California; Department of Surgical and Radiological Sciences (SMT), School of Veterinary Medicine, U.C. Davis, California; Great Ormond Street Hospital (MM), London, United Kingdom; and The Francis Crick Institute (MM), London, United Kingdom
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Kuang G, Halimitabrizi M, Edziah AA, Salowe R, O’Brien JM. The potential for mitochondrial therapeutics in the treatment of primary open-angle glaucoma: a review. Front Physiol 2023; 14:1184060. [PMID: 37601627 PMCID: PMC10433652 DOI: 10.3389/fphys.2023.1184060] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 07/21/2023] [Indexed: 08/22/2023] Open
Abstract
Glaucoma, an age-related neurodegenerative disease, is characterized by the death of retinal ganglion cells (RGCs) and the corresponding loss of visual fields. This disease is the leading cause of irreversible blindness worldwide, making early diagnosis and effective treatment paramount. The pathophysiology of primary open-angle glaucoma (POAG), the most common form of the disease, remains poorly understood. Current available treatments, which target elevated intraocular pressure (IOP), are not effective at slowing disease progression in approximately 30% of patients. There is a great need to identify and study treatment options that target other disease mechanisms and aid in neuroprotection for POAG. Increasingly, the role of mitochondrial injury in the development of POAG has become an emphasized area of research interest. Disruption in the function of mitochondria has been linked to problems with neurodevelopment and systemic diseases. Recent studies have shown an association between RGC death and damage to the cells' mitochondria. In particular, oxidative stress and disrupted oxidative phosphorylation dynamics have been linked to increased susceptibility of RGC mitochondria to secondary mechanical injury. Several mitochondria-targeted treatments for POAG have been suggested, including physical exercise, diet and nutrition, antioxidant supplementation, stem cell therapy, hypoxia exposure, gene therapy, mitochondrial transplantation, and light therapy. Studies have shown that mitochondrial therapeutics may have the potential to slow the progression of POAG by protecting against mitochondrial decline associated with age, genetic susceptibility, and other pathology. Further, these therapeutics may potentially target already present neuronal damage and symptom manifestations. In this review, the authors outline potential mitochondria-targeted treatment strategies and discuss their utility for use in POAG.
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Affiliation(s)
- Grace Kuang
- Perelman School of Medicine, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA, United States
- Penn Medicine Center for Genetics in Complex Diseases, University of Pennsylvania, Philadelphia, PA, United States
| | - Mina Halimitabrizi
- Perelman School of Medicine, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA, United States
- Penn Medicine Center for Genetics in Complex Diseases, University of Pennsylvania, Philadelphia, PA, United States
| | - Amy-Ann Edziah
- Perelman School of Medicine, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA, United States
- Penn Medicine Center for Genetics in Complex Diseases, University of Pennsylvania, Philadelphia, PA, United States
| | - Rebecca Salowe
- Perelman School of Medicine, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA, United States
- Penn Medicine Center for Genetics in Complex Diseases, University of Pennsylvania, Philadelphia, PA, United States
| | - Joan M. O’Brien
- Perelman School of Medicine, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA, United States
- Penn Medicine Center for Genetics in Complex Diseases, University of Pennsylvania, Philadelphia, PA, United States
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8
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Chen L, Liu Y. Clinical and genetic characteristics of children with COX20-associated mitochondrial disorder: case report and literature review. BMC Med Genomics 2023; 16:86. [PMID: 37095481 PMCID: PMC10124009 DOI: 10.1186/s12920-023-01513-y] [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: 11/27/2022] [Accepted: 04/08/2023] [Indexed: 04/26/2023] Open
Abstract
BACKGROUND The deficiency of cytochrome c oxidase 20 is a rare autosomal recessive mitochondrial disorder characterized by ataxia, dysarthria, dystonia and sensory neuropathy. CASE PRESENTATION In this study, we describe a patient from a non-consanguineous family exhibiting developmental delay, ataxia, hypotonia, dysarthria, strabismus, visual impairment and areflexia. An examination of nerve conduction showed a normal result at first but revealed axonal sensory neuropathy later. This situation has not been reported in any literatures. The whole-exome sequencing analysis revealed that the patient harbored compound heterozygous mutations (c.41 A > G and c.259G > T) of the COX20 gene. By literature review, 5 patients carried the same compound heterozygous mutations. CONCLUSION COX20 might be considered as a potential gene for the early-onset ataxia and the axonal sensory neuropathy. Our patient exhibited strabismus and visual impairment, which expands the clinical presentation of COX20 related mitochondrial disorders caused by the compound heterozygous variants (c.41 A > G and c.259G > T). However, a clear genotype/phenotype correlation has not yet been established. Additional researches and cases are needed to further confirm the correlation.
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Affiliation(s)
- Liqing Chen
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yan Liu
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
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9
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Lambiri DW, Levin LA. Modeling Reactive Oxygen Species-Induced Axonal Loss in Leber Hereditary Optic Neuropathy. Biomolecules 2022; 12:biom12101411. [PMID: 36291620 PMCID: PMC9599876 DOI: 10.3390/biom12101411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 09/29/2022] [Accepted: 09/30/2022] [Indexed: 11/17/2022] Open
Abstract
Leber hereditary optic neuropathy (LHON) is a rare syndrome that results in vision loss. A necessary but not sufficient condition for its onset is the existence of known mitochondrial DNA mutations that affect complex I biomolecular structure. Cybrids with LHON mutations generate higher rates of reactive oxygen species (ROS). This study models how ROS, particularly H2O2, could signal and execute the axonal degeneration process that underlies LHON. We modeled and explored several hypotheses regarding the influence of H2O2 on the dynamics of propagation of axonal degeneration in LHON. Zonal oxidative stress, corresponding to H2O2 gradients, correlated with the morphology of injury exhibited in the LHON pathology. If the axonal membrane is highly permeable to H2O2 and oxidative stress induces larger production of H2O2, small injuries could trigger cascading failures of neighboring axons. The cellular interdependence created by H2O2 diffusion, and the gradients created by tissue variations in H2O2 production and scavenging, result in injury patterns and surviving axonal loss distributions similar to LHON tissue samples. Specifically, axonal degeneration starts in the temporal optic nerve, where larger groups of small diameter fibers are located and propagates from that region. These findings correlate well with clinical observations of central loss of visual field, visual acuity, and color vision in LHON, and may serve as an in silico platform for modeling the mechanism of action for new therapeutics.
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Affiliation(s)
- Darius W. Lambiri
- Department of Physiology, McGill University, Montreal, QC H3G 1Y6, Canada
| | - Leonard A. Levin
- Department of Ophthalmology and Visual Sciences, McGill University, Montreal, QC H4A 3S5, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC H3A 2B4, Canada
- Correspondence:
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10
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Li P, Guo D, Zhang X, Ji K, Lv H, Zhang Y, Chen Z, Ma J, Fang Y, Liu Y. Compound Heterozygous COX20 Variants Impair the Function of Mitochondrial Complex IV to Cause a Syndrome Involving Ophthalmoplegia and Visual Failure. Front Neurol 2022; 13:873943. [PMID: 35651336 PMCID: PMC9149563 DOI: 10.3389/fneur.2022.873943] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 04/06/2022] [Indexed: 11/13/2022] Open
Abstract
The cytochrome c oxidase 20 (COX20) gene encodes a protein with a crucial role in the assembly of mitochondrial complex IV (CIV). Mutations in this gene can result in ataxia and muscle hypotonia. However, ophthalmoplegia and visual failure associated with COX20 mutation have not been examined previously. Moreover, the mechanism causing the phenotype of patients with COX20 variants to differ from that of patients with mutations in other genes impairing CIV assembly is unclear. In this investigation, the aim was to assess the relation between COX20 variants and CIV assembly. We performed detailed clinical, physical, and biochemical investigations of affected individuals. Western blotting, reverse transcription-polymerase chain reaction, and blue native-polyacrylamide gel electrophoresis were used to analyze the expression level of COX20 and oxidative phosphorylation. A Seahorse XF Cell Mito Stress Test and enzymatic activity analysis were performed to evaluate mitochondrial function. Whole-exome sequencing revealed the same compound heterozygous mutations (c.41A > G and c.222G > T, NM_198076) in COX20 in two siblings. This is the first description of ophthalmoplegia and visual failure associated with COX20 variants. In vitro analysis confirmed that the COX20 protein level was significantly decreased, impairing the assembly and activity of CIV in patients' fibroblast. Overexpression of COX20 using a transduced adenovirus partially restored the function of the patients' fibroblasts. Early-onset complex movement disorders may be closely related to COX20 variants. Our results broaden the clinical phenotypes of patients with COX20 variants showing ophthalmoplegia and visual failure. Additionally, dysfunction of COX20 protein can impair the assembly and activity of CIV.
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Affiliation(s)
- Peizheng Li
- Department of Neurology, Qilu Hospital, Shandong University, Jinan, China
| | - Dandan Guo
- Department of Neurology, Qilu Hospital, Shandong University, Jinan, China
| | - Xiufang Zhang
- Department of Neurology, Qilu Hospital, Shandong University, Jinan, China
| | - Kunqian Ji
- Department of Neurology, Qilu Hospital, Shandong University, Jinan, China
| | - Hongbo Lv
- Department of Neurology, Tianjin Medical University General Hospital, Tianjin, China
| | - Yanli Zhang
- Department of Neurology, Heze Municipal Hospital, Heze, China
| | - Zhichao Chen
- Department of Neurology, Qilu Hospital, Shandong University, Jinan, China
| | - Jun Ma
- Department of Neurology, Qilu Hospital, Shandong University, Jinan, China
| | - Yaofeng Fang
- Department of Neurology, Qilu Hospital, Shandong University, Jinan, China
| | - Yiming Liu
- Department of Neurology, Qilu Hospital, Shandong University, Jinan, China
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11
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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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12
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Ocular Hypertension Results in Hypoxia within Glia and Neurons throughout the Visual Projection. Antioxidants (Basel) 2022; 11:antiox11050888. [PMID: 35624752 PMCID: PMC9137916 DOI: 10.3390/antiox11050888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 04/24/2022] [Accepted: 04/27/2022] [Indexed: 12/03/2022] Open
Abstract
The magnitude and duration of hypoxia after ocular hypertension (OHT) has been a matter of debate due to the lack of tools to accurately report hypoxia. In this study, we established a topography of hypoxia in the visual pathway by inducing OHT in mice that express a fusion protein comprised of the oxygen-dependent degradation (ODD) domain of HIF-1α and a tamoxifen-inducible Cre recombinase (CreERT2) driven by a ubiquitous CAG promoter. After tamoxifen administration, tdTomato expression would be driven in cells that contain stabilized HIF-1α. Intraocular pressure (IOP) and visual evoked potential (VEP) were measured after OHT at 3, 14, and 28 days (d) to evaluate hypoxia induction. Immunolabeling of hypoxic cell types in the retina and optic nerve (ON) was performed, as well as retinal ganglion cell (RGC) and axon number quantification at each time point (6 h, 3 d, 14 d, 28 d). IOP elevation and VEP decrease were detected 3 d after OHT, which preceded RGC soma and axon loss at 14 and 28 d after OHT. Hypoxia was detected primarily in Müller glia in the retina, and microglia and astrocytes in the ON and optic nerve head (ONH). Hypoxia-induced factor (HIF-α) regulates the expression of glucose transporters 1 and 3 (GLUT1, 3) to support neuronal metabolic demand. Significant increases in GLUT1 and 3 proteins were observed in the retina and ON after OHT. Interestingly, neurons and endothelial cells within the superior colliculus in the brain also experienced hypoxia after OHT as determined by tdTomato expression. The highest intensity labeling for hypoxia was detected in the ONH. Initiation of OHT resulted in significant hypoxia that did not immediately resolve, with low-level hypoxia apparent out to 14 and 28 d, suggesting that continued hypoxia contributes to glaucoma progression. Restricted hypoxia in retinal neurons after OHT suggests a hypoxia management role for glia.
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13
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Ong J, Tavakkoli A, Strangman G, Zaman N, Kamran SA, Zhang Q, Ivkovic V, Lee AG. Neuro-ophthalmic Imaging and Visual Assessment Technology for Spaceflight Associated Neuro-ocular Syndrome (SANS). Surv Ophthalmol 2022; 67:1443-1466. [DOI: 10.1016/j.survophthal.2022.04.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 04/15/2022] [Accepted: 04/18/2022] [Indexed: 12/11/2022]
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14
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Zhou DB, Castanos MV, Geyman L, Rich CA, Tantraworasin A, Ritch R, Rosen RB. Mitochondrial Dysfunction in Primary Open-angle Glaucoma Characterized by Flavoprotein Fluorescence at the Optic Nerve Head. Ophthalmol Glaucoma 2021; 5:413-420. [PMID: 34968754 DOI: 10.1016/j.ogla.2021.12.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 12/18/2021] [Accepted: 12/22/2021] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To investigate the presence of flavoprotein fluorescence (FPF) at the optic nerve head (ONH) rim as a marker of mitochondrial dysfunction in primary open-angle glaucoma (POAG) and control eyes. DESIGN Retrospective cross-sectional study, with patients recruited from the New York Eye and Ear Infirmary of Mount Sinai. SUBJECTS, PARTICIPANTS, AND/OR CONTROLS A total of 86 eyes (50 eyes of 30 POAG patents and 36 eyes of 20 controls) were enrolled. The presence of POAG was defined by circumpapillary retinal nerve fiber layer thickness below the bottom fifth percentile of the normative database, glaucomatous ONH changes, and visual field defects on 24-2 tests. METHODS, INTERVENTION, OR TESTING POAG and control eyes were imaged using the OcuMet Beacon. A 23°x23° infrared scan was obtained, and an FPF scan was performed within a capture field spanning 13 degrees in diameter. The ONH margins on the infrared image were identified by software algorithms. FPF then was measured within an elliptical annulus around the ONH rim, with the inner and outer boundaries corresponding to 0.5 to 1.1 times the ONH rim size. MAIN OUTCOMES MEASURES FPF at the OHN rim in POAG and control eyes. RESULTS Differences in FPF between POAG and control eyes were characterized through mixed-effects logistic regression, adjusted for age and interocular pressure. FPF was significantly higher in POAG versus control eyes, with a mean±SD of 46.4±27.9 versus 28.0±11.7 (P<0.001), respectively. Evaluation of anatomical quadrants revealed greater FPF in POAG versus control eyes at the temporal (P=0.001), superior (P<0.001), nasal (P=0.002), and inferior (P=0.001) quadrants. Among POAG eyes, FPF showed correlation to visual field mean deviation (P<0.001), visual field pattern standard deviation (P=0.003), and circumpapillary retinal nerve fiber thickness (P=0.001) on linear mixed-effects models. CONCLUSIONS Higher FPF in POAG versus control eyes suggests the presence of mitochondrial dysfunction at the ONH rim in eyes with glaucomatous damage. The degree of FPF corresponds to disease severity, as measured by visual field and nerve fiber layer thickness metrics. FPF may thus represent a metabolic indicator of disease status that reveals the extent of injury in glaucoma.
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Affiliation(s)
- Davis B Zhou
- Department of Ophthalmology, New York Eye and Ear Infirmary of Mount Sinai; Department of Ophthalmology, Icahn School of Medicine at Mount Sinai
| | - Maria V Castanos
- Department of Ophthalmology, New York Eye and Ear Infirmary of Mount Sinai; Department of Ophthalmology, Icahn School of Medicine at Mount Sinai
| | - Lawrence Geyman
- Einhorn Clinical Research Center, New York Eye and Ear Infirmary of Mount Sinai, New York; Department of Ophthalmology, Illinois Eye and Ear Infirmary, Chicago, Illinois
| | | | - Apichat Tantraworasin
- Clinical Epidemiology and Clinical Statistic Center, and Department of Surgery, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Robert Ritch
- Einhorn Clinical Research Center, New York Eye and Ear Infirmary of Mount Sinai, New York
| | - Richard B Rosen
- Department of Ophthalmology, New York Eye and Ear Infirmary of Mount Sinai; Department of Ophthalmology, Icahn School of Medicine at Mount Sinai.
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15
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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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16
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Yang TC, Yarmishyn AA, Yang YP, Lu PC, Chou SJ, Wang ML, Lin TC, Hwang DK, Chou YB, Chen SJ, Yu WK, Wang AG, Hsu CC, Chiou SH. Mitochondrial transport mediates survival of retinal ganglion cells in affected LHON patients. Hum Mol Genet 2021; 29:1454-1464. [PMID: 32277753 DOI: 10.1093/hmg/ddaa063] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 03/02/2020] [Accepted: 03/30/2020] [Indexed: 01/17/2023] Open
Abstract
The mutations in the genes encoding the subunits of complex I of the mitochondrial electron transport chain are the most common cause of Leber's hereditary optic neuropathy (LHON), a maternal hereditary disease characterized by retinal ganglion cell (RGC) degeneration. The characteristics of incomplete penetrance indicate that nuclear genetic and environmental factors also determine phenotypic expression of LHON. Therefore, further understanding of the role of mutant mitochondrial nicotinamide adenine dinucleotide dehydrogenase subunit proteins and nuclear genetic factors/environmental effects in the etiology of LHON is needed. In this study, we generated human-induced pluripotent stem cells (hiPSCs) from healthy control, unaffected LHON mutation carrier, and affected LHON patient. hiPSC-derived RGCs were used to study the differences between affected and unaffected carriers of mitochondrial DNA point mutation m.11778G > A in the MT-ND4 gene. We found that both mutated cell lines were characterized by increase in reactive oxygen species production, however, only affected cell line had increased levels of apoptotic cells. We found a significant increase in retrograde mitochondria and a decrease in stationary mitochondria in the affected RGC axons. In addition, the messenger RNA and protein levels of KIF5A in the LHON-affected RGCs were significantly reduced. Antioxidant N-acetyl-L-cysteine could restore the expression of KIF5A and the normal pattern of mitochondrial movement in the affected RGCs. To conclude, we found essential differences in the mutually dependent processes of oxidative stress, mitochondrial transport and apoptosis between two LHON-specific mutation carrier RGC cell lines, asymptomatic carrier and disease-affected, and identified KIF5A as a central modulator of these differences.
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Affiliation(s)
- Tien-Chun Yang
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | | | - Yi-Ping Yang
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan.,School of Pharmaceutical Sciences, National Yang-Ming University, Taipei 11221, Taiwan.,School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan
| | - Pin-Chen Lu
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | - Shih-Jie Chou
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan.,Institute of Pharmacology, National Yang-Ming University, Taipei 11221, Taiwan
| | - Mong-Lien Wang
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan.,School of Pharmaceutical Sciences, National Yang-Ming University, Taipei 11221, Taiwan.,School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan.,Institute of Pharmacology, National Yang-Ming University, Taipei 11221, Taiwan
| | - Tai-Chi Lin
- School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan.,Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | - De-Kuang Hwang
- School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan.,Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | - Yu-Bai Chou
- School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan.,Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | - Shih-Jen Chen
- School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan.,Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | - Wei-Kuang Yu
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | - An-Guor Wang
- School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan.,Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | - Chih-Chien Hsu
- School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan.,Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | - Shih-Hwa Chiou
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan.,School of Pharmaceutical Sciences, National Yang-Ming University, Taipei 11221, Taiwan.,Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 11217, Taiwan
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17
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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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18
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Immune Responses in the Glaucomatous Retina: Regulation and Dynamics. Cells 2021; 10:cells10081973. [PMID: 34440742 PMCID: PMC8391899 DOI: 10.3390/cells10081973] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 07/27/2021] [Accepted: 07/28/2021] [Indexed: 12/27/2022] Open
Abstract
Glaucoma is a multifactorial disease resulting in progressive vision loss due to retinal ganglion cell (RGC) dysfunction and death. Early events in the pathobiology of the disease include oxidative, metabolic, or mechanical stress that acts upon RGC, causing these to rapidly release danger signals, including extracellular ATP, resulting in micro- and macroglial activation and neuroinflammation. Danger signaling also leads to the formation of inflammasomes in the retina that enable maturation of proinflammatory cytokines such IL-1β and IL-18. Chronic neuroinflammation can have directly damaging effects on RGC, but it also creates a proinflammatory environment and compromises the immune privilege of the retina. In particular, continuous synthesis of proinflammatory mediators such as TNFα, IL-1β, and anaphylatoxins weakens the blood–retina barrier and recruits or activates T-cells. Recent data have demonstrated that adaptive immune responses strongly exacerbate RGC loss in animal models of the disease as T-cells appear to target heat shock proteins displayed on the surface of stressed RGC to cause their apoptotic death. It is possible that dysregulation of these immune responses contributes to the continued loss of RGC in some patients.
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19
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Lenaers G, Neutzner A, Le Dantec Y, Jüschke C, Xiao T, Decembrini S, Swirski S, Kieninger S, Agca C, Kim US, Reynier P, Yu-Wai-Man P, Neidhardt J, Wissinger B. Dominant optic atrophy: Culprit mitochondria in the optic nerve. Prog Retin Eye Res 2021; 83:100935. [PMID: 33340656 DOI: 10.1016/j.preteyeres.2020.100935] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 12/05/2020] [Accepted: 12/09/2020] [Indexed: 12/14/2022]
Abstract
Dominant optic atrophy (DOA) is an inherited mitochondrial disease leading to specific degeneration of retinal ganglion cells (RGCs), thus compromising transmission of visual information from the retina to the brain. Usually, DOA starts during childhood and evolves to poor vision or legal blindness, affecting the central vision, whilst sparing the peripheral visual field. In 20% of cases, DOA presents as syndromic disorder, with secondary symptoms affecting neuronal and muscular functions. Twenty years ago, we demonstrated that heterozygous mutations in OPA1 are the most frequent molecular cause of DOA. Since then, variants in additional genes, whose functions in many instances converge with those of OPA1, have been identified by next generation sequencing. OPA1 encodes a dynamin-related GTPase imported into mitochondria and located to the inner membrane and intermembrane space. The many OPA1 isoforms, resulting from alternative splicing of three exons, form complex homopolymers that structure mitochondrial cristae, and contribute to fusion of the outer membrane, thus shaping the whole mitochondrial network. Moreover, OPA1 is required for oxidative phosphorylation, maintenance of mitochondrial genome, calcium homeostasis and regulation of apoptosis, thus making OPA1 the Swiss army-knife of mitochondria. Understanding DOA pathophysiology requires the understanding of RGC peculiarities with respect to OPA1 functions. Besides the tremendous energy requirements of RGCs to relay visual information from the eye to the brain, these neurons present unique features related to their differential environments in the retina, and to the anatomical transition occurring at the lamina cribrosa, which parallel major adaptations of mitochondrial physiology and shape, in the pre- and post-laminar segments of the optic nerve. Three DOA mouse models, with different Opa1 mutations, have been generated to study intrinsic mechanisms responsible for RGC degeneration, and these have further revealed secondary symptoms related to mitochondrial dysfunctions, mirroring the more severe syndromic phenotypes seen in a subgroup of patients. Metabolomics analyses of cells, mouse organs and patient plasma mutated for OPA1 revealed new unexpected pathophysiological mechanisms related to mitochondrial dysfunction, and biomarkers correlated quantitatively to the severity of the disease. Here, we review and synthesize these data, and propose different approaches for embracing possible therapies to fulfil the unmet clinical needs of this disease, and provide hope to affected DOA patients.
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Affiliation(s)
- Guy Lenaers
- MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, Angers University and Hospital, Angers, France.
| | - Albert Neutzner
- Department of Biomedicine, University Hospital Basel, University of Basel, Basel, Switzerland; Department of Ophthalmology University Hospital Basel, University of Basel, Basel, Switzerland.
| | - Yannick Le Dantec
- MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, Angers University and Hospital, Angers, France
| | - Christoph Jüschke
- Human Genetics, Faculty VI - School of Medicine and Health Sciences, University of Oldenburg, Oldenburg, Germany
| | - Ting Xiao
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Center for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Sarah Decembrini
- Department of Biomedicine, University Hospital Basel, University of Basel, Basel, Switzerland; Department of Ophthalmology University Hospital Basel, University of Basel, Basel, Switzerland
| | - Sebastian Swirski
- Human Genetics, Faculty VI - School of Medicine and Health Sciences, University of Oldenburg, Oldenburg, Germany
| | - Sinja Kieninger
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Center for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Cavit Agca
- Molecular Biology, Genetics and Bioengineering Program, Sabanci University, Istanbul, Turkey; Nanotechnology Research and Application Center (SUNUM), Sabanci University, Istanbul, Turkey
| | - Ungsoo S Kim
- Kim's Eye Hospital, Seoul, South Korea; Cambridge Centre for Brain Repair and MRC Mitochondrial Biology Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK; Cambridge Eye Unit, Addenbrooke's Hospital, Cambridge University Hospitals, Cambridge, UK; Moorfields Eye Hospital, London, UK
| | - Pascal Reynier
- MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, Angers University and Hospital, Angers, France; Department of Biochemistry, University Hospital of Angers, Angers, France
| | - Patrick Yu-Wai-Man
- Cambridge Centre for Brain Repair and MRC Mitochondrial Biology Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK; Cambridge Eye Unit, Addenbrooke's Hospital, Cambridge University Hospitals, Cambridge, UK; Moorfields Eye Hospital, London, UK; UCL Institute of Ophthalmology, University College London, London, UK
| | - John Neidhardt
- Human Genetics, Faculty VI - School of Medicine and Health Sciences, University of Oldenburg, Oldenburg, Germany; Research Center Neurosensory Science, University Oldenburg, Oldenburg, Germany.
| | - Bernd Wissinger
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Center for Ophthalmology, University of Tübingen, Tübingen, Germany.
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20
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Wilkison SJ, Bright CL, Vancini R, Song DJ, Bomze HM, Cartoni R. Local Accumulation of Axonal Mitochondria in the Optic Nerve Glial Lamina Precedes Myelination. Front Neuroanat 2021; 15:678501. [PMID: 34093141 PMCID: PMC8173055 DOI: 10.3389/fnana.2021.678501] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 04/26/2021] [Indexed: 11/18/2022] Open
Abstract
Mitochondria are essential for neurons and must be optimally distributed along their axon to fulfill local functions. A high density of mitochondria has been observed in retinal ganglion cell (RGC) axons of an unmyelinated region of the optic nerve, called the glial lamina (GL) in mouse (lamina cribrosa in human). In glaucoma, the world's leading cause of irreversible blindness, the GL is the epicenter of RGC degeneration and is connected to mitochondrial dysfunction. It is generally accepted that the local accumulation of mitochondria in the GL is established due to the higher energy requirement of unmyelinated axons. Here we revisit the connection between mitochondrial positioning and myelin in RGC axons. We show that the high density of mitochondria in the GL is restricted to larger axons and is established before myelination. Thus, contrary to a longstanding belief in the field, the myelination pattern is not responsible for the establishment of the local accumulation of mitochondria in GL axons. Our findings open new research avenues likely critical to understanding the pathophysiology of glaucoma.
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Affiliation(s)
- Samantha J Wilkison
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, United States.,Department of Ophthalmology, Duke University School of Medicine, Durham, NC, United States
| | - Cora L Bright
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, United States.,Department of Ophthalmology, Duke University School of Medicine, Durham, NC, United States
| | - Ricardo Vancini
- Department of Pathology, Duke University School of Medicine, Durham, NC, United States
| | - Daniel J Song
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, United States.,Department of Ophthalmology, Duke University School of Medicine, Durham, NC, United States
| | - Howard M Bomze
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, United States.,Department of Ophthalmology, Duke University School of Medicine, Durham, NC, United States
| | - Romain Cartoni
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, United States.,Department of Ophthalmology, Duke University School of Medicine, Durham, NC, United States
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21
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Soldatov VO, Kukharsky MS, Belykh AE, Sobolev AM, Deykin AV. Retinal Damage in Amyotrophic Lateral Sclerosis: Underlying Mechanisms. Eye Brain 2021; 13:131-146. [PMID: 34012311 PMCID: PMC8128130 DOI: 10.2147/eb.s299423] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 03/04/2021] [Indexed: 01/04/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease resulting in a gradual loss of motor neuron function. Although ophthalmic complaints are not presently considered a classic symptom of ALS, retinal changes such as thinning, axonal degeneration and inclusion bodies have been found in many patients. Retinal abnormalities observed in postmortem human tissues and animal models are similar to spinal cord changes in ALS. These findings are not dramatically unexpected because retina shares an ontogenetic relationship with the brain, and many genes are associated both with neurodegeneration and retinal diseases. Experimental studies have demonstrated that ALS affects many “vulnerable points” of the retina. Aggregate deposition, impaired nuclear protein import, endoplasmic reticulum stress, glutamate excitotoxicity, vascular regression, and mitochondrial dysfunction are factors suspected as being the main cause of motor neuron damage in ALS. Herein, we show that all of these pathways can affect retinal cells in the same way as motor neurons. Furthermore, we suppose that understanding the patterns of neuro-ophthalmic interaction in ALS can help in the diagnosis and treatment of this disease.
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Affiliation(s)
- Vladislav O Soldatov
- Core Facility Centre, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia.,Department of Pharmacology and Clinical Pharmacology, Belgorod State National Research University, Belgorod, Russia
| | - Michail S Kukharsky
- Department of General and Cell Biology, Faculty of Medical Biology, Pirogov Russian National Research Medical University, Moscow, Russia.,Laboratory of Genetic Modelling of Neurodegenerative Processes, Institute of Physiologically Active Compounds, Russian Academy of Sciences, Chernogolovka, Russia
| | - Andrey E Belykh
- Department of Pathophysiology, Kursk State Medical University, Kursk, Russia
| | - Andrey M Sobolev
- Laboratory of Genetic Modelling of Neurodegenerative Processes, Institute of Physiologically Active Compounds, Russian Academy of Sciences, Chernogolovka, Russia
| | - Alexey V Deykin
- Department of Pharmacology and Clinical Pharmacology, Belgorod State National Research University, Belgorod, Russia.,Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
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22
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Neuroinflammatory Mechanisms of Mitochondrial Dysfunction and Neurodegeneration in Glaucoma. J Ophthalmol 2021; 2021:4581909. [PMID: 33953963 PMCID: PMC8064803 DOI: 10.1155/2021/4581909] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2020] [Revised: 06/29/2020] [Accepted: 03/23/2021] [Indexed: 12/13/2022] Open
Abstract
The exact mechanism of retinal ganglion cell loss in the pathogenesis of glaucoma is yet to be understood. Mitochondrial damage-associated molecular patterns (DAMPs) resulting from mitochondrial dysfunction have been linked to Leber's hereditary optic neuropathy and autosomal dominant optic atrophy, as well as to brain neurodegenerative diseases. Recent evidence shows that, in conditions where mitochondria are damaged, a sustained inflammatory response and downstream pathological inflammation may ensue. Mitochondrial damage has been linked to the accumulation of age-related mitochondrial DNA mutations and mitochondrial dysfunction, possibly through aberrant reactive oxygen species production and defective mitophagy. The present review focuses on how mitochondrial dysfunction may overwhelm the ability of neurons and glial cells to adequately maintain homeostasis and how mitochondria-derived DAMPs trigger the immune system and induce neurodegeneration.
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23
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Liu H, Prokosch V. Energy Metabolism in the Inner Retina in Health and Glaucoma. Int J Mol Sci 2021; 22:ijms22073689. [PMID: 33916246 PMCID: PMC8036449 DOI: 10.3390/ijms22073689] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 03/22/2021] [Accepted: 03/29/2021] [Indexed: 02/07/2023] Open
Abstract
Glaucoma, the leading cause of irreversible blindness, is a heterogeneous group of diseases characterized by progressive loss of retinal ganglion cells (RGCs) and their axons and leads to visual loss and blindness. Risk factors for the onset and progression of glaucoma include systemic and ocular factors such as older age, lower ocular perfusion pressure, and intraocular pressure (IOP). Early signs of RGC damage comprise impairment of axonal transport, downregulation of specific genes and metabolic changes. The brain is often cited to be the highest energy-demanding tissue of the human body. The retina is estimated to have equally high demands. RGCs are particularly active in metabolism and vulnerable to energy insufficiency. Understanding the energy metabolism of the inner retina, especially of the RGCs, is pivotal for understanding glaucoma’s pathophysiology. Here we review the key contributors to the high energy demands in the retina and the distinguishing features of energy metabolism of the inner retina. The major features of glaucoma include progressive cell death of retinal ganglions and optic nerve damage. Therefore, this review focuses on the energetic budget of the retinal ganglion cells, optic nerve and the relevant cells that surround them.
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24
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Calkins DJ. Adaptive responses to neurodegenerative stress in glaucoma. Prog Retin Eye Res 2021; 84:100953. [PMID: 33640464 DOI: 10.1016/j.preteyeres.2021.100953] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 02/08/2021] [Accepted: 02/19/2021] [Indexed: 12/12/2022]
Abstract
Glaucoma causes loss of vision through degeneration of the retinal ganglion cell (RGC) projection to the brain. The disease is characterized by sensitivity to intraocular pressure (IOP) conveyed at the optic nerve head, through which RGC axons pass unmyelinated to form the optic nerve. From this point, a pathogenic triumvirate comprising inflammatory, oxidative, and metabolic stress influence both proximal structures in the retina and distal structures in the optic projection. This review focuses on metabolic stress and how the optic projection may compensate through novel adaptive mechanisms to protect excitatory signaling to the brain. In the retina and proximal nerve head, the unmyelinated RGC axon segment is energy-inefficient, which leads to increased demand for adenosine-5'-triphosphate (ATP) at the risk of vulnerability to Ca2+-related metabolic and oxidative pressure. This vulnerability may underlie the bidirectional nature of progression. However, recent evidence highlights that the optic projection in glaucoma is not passive but rather demonstrates adaptive processes that may push back against neurodegeneration. In the retina, even as synaptic and dendritic pruning ensues, early progression involves enhanced excitability of RGCs. Enhancement involves depolarization of the resting membrane potential and increased response to light, independent of RGC morphological type. This response is axogenic, arising from increased levels and translocation of voltage-gated sodium channels (NaV) in the unmyelinated segment. During this same early period, large-scale networks of gap-junction coupled astrocytes redistribute metabolic resources to the optic projection stressed by elevated IOP to slow loss of axon function. This redistribution may reflect more local remodeling, as astrocyte processes respond to focal metabolic duress by boosting glycogen turnover in response to axonal activity in an effort to promote survival of the healthiest axons. Both enhanced excitability and metabolic redistribution are transient, indicating that the same adaptive mechanisms that apparently serve to slow progression ultimately may be too expensive for the system to sustain over longer periods.
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Affiliation(s)
- David J Calkins
- The Vanderbilt Eye Institute, Nashville, TN, USA; Vanderbilt Vision Research Center, Vanderbilt University Medical Center, 1161 21st Ave S, AA7100 Medical Center North Nashville, Tennessee, 37232, USA.
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25
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Ineichen BV, Zhu K, Carlström KE. Axonal mitochondria adjust in size depending on g-ratio of surrounding myelin during homeostasis and advanced remyelination. J Neurosci Res 2020; 99:793-805. [PMID: 33368634 PMCID: PMC7898477 DOI: 10.1002/jnr.24767] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 11/14/2020] [Indexed: 12/11/2022]
Abstract
Demyelinating pathology is common in many neurological diseases such as multiple sclerosis, stroke, and Alzheimer's disease and results in axonal energy deficiency, dysfunctional axonal propagation, and neurodegeneration. During myelin repair and also during myelin homeostasis, mutual regulative processes between axons and myelin sheaths are known to be essential. However, proficient tools are lacking to characterize axon‐myelin interdependence during (re)myelination. Thus, we herein investigated adaptions in myelin sheath g‐ratio as a proxy for myelin thickness and axon metabolic status during homeostasis and myelin repair, by using axonal mitochondrial size as a proxy for axonal metabolic status. We found that axons with thinner myelin sheaths had larger axonal mitochondria; this was true for across different central nervous system tracts as well as across species, including humans. The link between myelin sheath thickness and mitochondrial size was temporarily absent during demyelination but reestablished during advanced remyelination, as shown in two commonly used animal models of toxic demyelination. By further exploring this association in mice with either genetically induced mitochondrial or myelin dysfunction, we show that axonal mitochondrial size adjusts in response to the thickness of the myelin sheath but not vice versa. This pinpoints the relevance of mitochondrial adaptation upon myelin repair and might open a new therapeutic window for remyelinating therapies.
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Affiliation(s)
- Benjamin V Ineichen
- Department of Clinical Neurosciences, Karolinska Institutet, Center for Molecular Medicine, Karolinska Hospital at Solna, Stockholm, Sweden
| | - Keying Zhu
- Department of Clinical Neurosciences, Karolinska Institutet, Center for Molecular Medicine, Karolinska Hospital at Solna, Stockholm, Sweden
| | - Karl E Carlström
- Department of Clinical Neurosciences, Karolinska Institutet, Center for Molecular Medicine, Karolinska Hospital at Solna, Stockholm, Sweden.,Laboratory of Molecular Neurobiology, Department Medical Biochemistry and Biophysics, Biomedicum, Karolinska Institutet, Stockholm, Sweden
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26
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Oikawa K, Teixeira LBC, Keikhosravi A, Eliceiri KW, McLellan GJ. Microstructure and resident cell-types of the feline optic nerve head resemble that of humans. Exp Eye Res 2020; 202:108315. [PMID: 33091431 DOI: 10.1016/j.exer.2020.108315] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 10/09/2020] [Accepted: 10/16/2020] [Indexed: 01/15/2023]
Abstract
The lamina cribrosa (LC) region of the optic nerve head (ONH) is considered a primary site for glaucomatous damage. In humans, biology of this region reflects complex interactions between retinal ganglion cell (RGC) axons and other resident ONH cell-types including astrocytes, lamina cribrosa cells, microglia and oligodendrocytes, as well as ONH microvasculature and collagenous LC beams. However, species differences in the microanatomy of this region could profoundly impact efforts to model glaucoma pathobiology in a research setting. In this study, we characterized resident cell-types, ECM composition and ultrastructure in relation to microanatomy of the ONH in adult domestic cats (Felis catus). Longitudinal and transverse cryosections of ONH tissues were immunolabeled with astrocyte, microglia/macrophage, oligodendrocyte, LC cell and vascular endothelial cell markers. Collagen fiber structure of the LC was visualized by second harmonic generation (SHG) with multiphoton microscopy. Fibrous astrocytes form glial fibrillary acidic protein (GFAP)-positive glial columns in the pre-laminar region, and cover the collagenous plates of the LC region in lamellae oriented perpendicular to the axons. GFAP-negative and alpha-smooth muscle actin-positive LC cells were identified in the feline ONH. IBA-1 positive immune cells and von Willebrand factor-positive blood vessel endothelial cells are also identifiable throughout the feline ONH. As in humans, myelination commences with a population of oligodendrocytes in the retro-laminar region of the feline ONH. Transmission electron microscopy confirmed the presence of capillaries and LC cells that extend thin processes in the core of the collagenous LC beams. In conclusion, the feline ONH closely recapitulates the complexity of the ONH of humans and non-human primates, with diverse ONH cell-types and a robust collagenous LC, within the beams of which, LC cells and capillaries reside. Thus, studies in a feline inherited glaucoma model have the potential to play a key role in enhancing our understanding of ONH cellular and molecular processes in glaucomatous optic neuropathy.
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Affiliation(s)
- Kazuya Oikawa
- Ophthalmology & Visual Sciences, University of Wisconsin-Madison, Madison, WI, USA; Surgical Sciences, University of Wisconsin-Madison, WI, USA; McPherson Eye Research Institute, Madison, WI, USA
| | - Leandro B C Teixeira
- McPherson Eye Research Institute, Madison, WI, USA; Pathobiological Sciences, University of Wisconsin-Madison, WI, USA
| | - Adib Keikhosravi
- Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Kevin W Eliceiri
- McPherson Eye Research Institute, Madison, WI, USA; Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Gillian J McLellan
- Ophthalmology & Visual Sciences, University of Wisconsin-Madison, Madison, WI, USA; Surgical Sciences, University of Wisconsin-Madison, WI, USA; McPherson Eye Research Institute, Madison, WI, USA.
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27
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Alcover-Sanchez B, Garcia-Martin G, Escudero-Ramirez J, Gonzalez-Riano C, Lorenzo P, Gimenez-Cassina A, Formentini L, de la Villa-Polo P, Pereira MP, Wandosell F, Cubelos B. Absence of R-Ras1 and R-Ras2 causes mitochondrial alterations that trigger axonal degeneration in a hypomyelinating disease model. Glia 2020; 69:619-637. [PMID: 33010069 DOI: 10.1002/glia.23917] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 08/18/2020] [Accepted: 09/21/2020] [Indexed: 12/11/2022]
Abstract
Fast synaptic transmission in vertebrates is critically dependent on myelin for insulation and metabolic support. Myelin is produced by oligodendrocytes (OLs) that maintain multilayered membrane compartments that wrap around axonal fibers. Alterations in myelination can therefore lead to severe pathologies such as multiple sclerosis. Given that hypomyelination disorders have complex etiologies, reproducing clinical symptoms of myelin diseases from a neurological perspective in animal models has been difficult. We recently reported that R-Ras1-/- and/or R-Ras2-/- mice, which lack GTPases essential for OL survival and differentiation processes, present different degrees of hypomyelination in the central nervous system with a compounded hypomyelination in double knockout (DKO) mice. Here, we discovered that the loss of R-Ras1 and/or R-Ras2 function is associated with aberrant myelinated axons with increased numbers of mitochondria, and a disrupted mitochondrial respiration that leads to increased reactive oxygen species levels. Consequently, aberrant myelinated axons are thinner with cytoskeletal phosphorylation patterns typical of axonal degeneration processes, characteristic of myelin diseases. Although we observed different levels of hypomyelination in a single mutant mouse, the combined loss of function in DKO mice lead to a compromised axonal integrity, triggering the loss of visual function. Our findings demonstrate that the loss of R-Ras function reproduces several characteristics of hypomyelinating diseases, and we therefore propose that R-Ras1-/- and R-Ras2-/- neurological models are valuable approaches for the study of these myelin pathologies.
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Affiliation(s)
- Berta Alcover-Sanchez
- Departamento de Biología Molecular and Centro Biología Molecular "Severo Ochoa", Universidad Autónoma de Madrid - Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Gonzalo Garcia-Martin
- Departamento de Biología Molecular and Centro Biología Molecular "Severo Ochoa", Universidad Autónoma de Madrid - Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Juan Escudero-Ramirez
- Departamento de Biología Molecular and Centro Biología Molecular "Severo Ochoa", Universidad Autónoma de Madrid - Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Carolina Gonzalez-Riano
- CEMBIO (Centre for Metabolomics and Bioanalysis), Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Madrid, Spain
| | - Paz Lorenzo
- CEMBIO (Centre for Metabolomics and Bioanalysis), Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Madrid, Spain
| | - Alfredo Gimenez-Cassina
- Departamento de Biología Molecular and Centro Biología Molecular "Severo Ochoa", Universidad Autónoma de Madrid - Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Laura Formentini
- Departamento de Biología Molecular and Centro Biología Molecular "Severo Ochoa", Universidad Autónoma de Madrid - Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Pedro de la Villa-Polo
- Departamento de Biología de Sistemas, Universidad de Alcalá, Madrid, Spain.,Grupo de Neurofisiología Visual, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
| | - Marta P Pereira
- Departamento de Biología Molecular and Centro Biología Molecular "Severo Ochoa", Universidad Autónoma de Madrid - Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Francisco Wandosell
- Departamento de Biología Molecular and Centro Biología Molecular "Severo Ochoa", Universidad Autónoma de Madrid - Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Beatriz Cubelos
- Departamento de Biología Molecular and Centro Biología Molecular "Severo Ochoa", Universidad Autónoma de Madrid - Consejo Superior de Investigaciones Científicas, Madrid, Spain
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28
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Abstract
This review focuses on recent progress in understanding the role of mitochondrial markers in the context of mitochondrial dysfunction in glaucoma and discussing new therapeutic approaches to modulate mitochondrial function and potentially lead to improved outcomes in glaucoma.
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29
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Hanyuda A, Rosner BA, Wiggs JL, Willett WC, Tsubota K, Pasquale LR, Kang JH. Low-carbohydrate-diet scores and the risk of primary open-angle glaucoma: data from three US cohorts. Eye (Lond) 2020; 34:1465-1475. [PMID: 32123310 PMCID: PMC7470850 DOI: 10.1038/s41433-020-0820-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 02/11/2020] [Accepted: 02/11/2020] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND/OBJECTIVES To assess the long-term association between low-carbohydrate dietary patterns and incident primary open-angle glaucoma (POAG), and POAG subtypes defined by highest untreated intraocular pressure (IOP) and by pattern of visual field (VF) loss at diagnosis. SUBJECTS/METHODS We followed 185,638 participants of three large US prospective cohorts biennially (1976-2016, 1986-2016 and 1991-2017). Deciles of three low-carbohydrate-diet scores were calculated to represent adherence to diets lower in carbohydrate and higher in protein and fat from any source, animal sources or plant sources. We confirmed POAG cases (n = 2112) by medical record review and used Cox proportional hazards models to estimate multivariable-adjusted relative risks (MVRRs) and 95% confidence intervals (CIs). RESULTS There was no association between the three types of low-carbohydrate-diet scores and POAG: the MVRR for POAG in the highest vs. lowest deciles was 1.13 (95% CI, 0.91-1.39; Ptrend = 0.40) for the overall score; 1.10 (95% CI, 0.89-1.35; Ptrend = 0.38) for the animal score and 0.96 (95% CI, 0.79-1.18; Ptrend = 0.88) for the vegetable score. No differential associations by IOP level was found (Pheterogeneity ≥ 0.06). However, the vegetable score showed a suggestive inverse association with early paracentral VF loss (highest vs. lowest decile MVRR = 0.78 [95% CI, 0.55-1.10]; Ptrend = 0.12) but not with peripheral VF loss only (MVRR = 1.09 [95% CI, 0.83-1.44]; Ptrend = 0.14; Pheterogeneity = 0.03). CONCLUSIONS Low-carbohydrate diets were not associated with risk of POAG. Our data suggested that higher consumption of fat and protein from vegetable sources substituting for carbohydrates was associated with lower risk of the POAG subtype with initial paracentral VF loss.
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Affiliation(s)
- Akiko Hanyuda
- Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
- Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan.
- Epidemiology and Prevention Group, Center for Public Health Sciences, National Cancer Center, Tokyo, Japan.
| | - Bernard A Rosner
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA, USA
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Janey L Wiggs
- Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, MA, USA
| | - Walter C Willett
- Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, USA
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Kazuo Tsubota
- Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan
| | - Louis R Pasquale
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
- Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Jae H Kang
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
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30
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Retinal energy metabolism in health and glaucoma. Prog Retin Eye Res 2020; 81:100881. [PMID: 32712136 DOI: 10.1016/j.preteyeres.2020.100881] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 06/25/2020] [Accepted: 06/28/2020] [Indexed: 01/17/2023]
Abstract
Energy metabolism refers to the processes by which life transfers energy to do cellular work. The retina's relatively large energy demands make it vulnerable to energy insufficiency. In addition, evolutionary pressures to optimize human vision have been traded against retinal ganglion cell bioenergetic fragility. Details of the metabolic profiles of the different retinal cells remain poorly understood and are challenging to resolve. Detailed immunohistochemical mapping of the energy pathway enzymes and substrate transporters has provided some insights and highlighted interspecies differences. The different spatial metabolic patterns between the vascular and avascular retinas can account for some inconsistent data in the literature. There is a consilience of evidence that at least some individuals with glaucoma have impaired RGC energy metabolism, either due to impaired nutrient supply or intrinsic metabolic perturbations. Bioenergetic-based therapy for glaucoma has a compelling pathophysiological foundation and is supported by recent successes in animal models. Recent demonstrations of visual and electrophysiological neurorecovery in humans with glaucoma is highly encouraging and motivates longer duration trials investigating bioenergetic neuroprotection.
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31
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Pleiotropic Mitochondria: The Influence of Mitochondria on Neuronal Development and Disease. J Neurosci 2020; 39:8200-8208. [PMID: 31619488 DOI: 10.1523/jneurosci.1157-19.2019] [Citation(s) in RCA: 102] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 08/09/2019] [Accepted: 08/10/2019] [Indexed: 02/08/2023] Open
Abstract
Mitochondria play many important biological roles, including ATP production, lipid biogenesis, ROS regulation, and calcium clearance. In neurons, the mitochondrion is an essential organelle for metabolism and calcium homeostasis. Moreover, mitochondria are extremely dynamic and able to divide, fuse, and move along microtubule tracks to ensure their distribution to the neuronal periphery. Mitochondrial dysfunction and altered mitochondrial dynamics are observed in a wide range of conditions, from impaired neuronal development to various neurodegenerative diseases. Novel imaging techniques and genetic tools provide unprecedented access to the physiological roles of mitochondria by visualizing mitochondrial trafficking, morphological dynamics, ATP generation, and ultrastructure. Recent studies using these new techniques have unveiled the influence of mitochondria on axon branching, synaptic function, calcium regulation with the ER, glial cell function, neurogenesis, and neuronal repair. This review provides an overview of the crucial roles played by mitochondria in the CNS in physiological and pathophysiological conditions.
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32
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Grzybowski A, Och M, Kanclerz P, Leffler C, Moraes CGD. Primary Open Angle Glaucoma and Vascular Risk Factors: A Review of Population Based Studies from 1990 to 2019. J Clin Med 2020; 9:E761. [PMID: 32168880 PMCID: PMC7141380 DOI: 10.3390/jcm9030761] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 02/18/2020] [Accepted: 02/28/2020] [Indexed: 12/17/2022] Open
Abstract
Glaucoma is one of the leading causes of blindness worldwide, and as the proportion of those over age 40 increases, so will the prevalence of glaucoma. The pathogenesis of primary open angle glaucoma (POAG) is unclear and multiple ocular risk factors have been proposed, including intraocular pressure, ocular perfusion pressure, ocular blood flow, myopia, central corneal thickness, and optic disc hemorrhages. The purpose of this review was to analyze the association between systemic vascular risk factors (including hypertension, diabetes, age, and migraine) and POAG, based on major epidemiological studies. Reports presenting the association between POAG and systemic vascular risk factors included a total of over 50,000 patients. Several epidemiological studies confirmed the importance of vascular risk factors, particularly hypertension and blood pressure dipping, in the pathogenesis and progression of glaucomatous optic neuropathy. We found that diabetes mellitus is associated with elevated intraocular pressure, but has no clear association with POAG. No significant correlation between migraine and POAG was found, however, the definition of migraine varied between studies.
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Affiliation(s)
- Andrzej Grzybowski
- Institute for Research in Ophthalmology, Foundation for Ophthalmology Development, 61-285 Poznan, Poland
| | - Mariusz Och
- Department of Ophthalmology, The Voivodal Specialistic Hospital in Olsztyn, 10-447 Olsztyn, Poland
| | - Piotr Kanclerz
- Department of Ophthalmology, Hygeia Clinic, 80-286 Gdańsk, Poland
| | - Christopher Leffler
- Department of Ophthalmology, Virginia Commonwealth University, Richmond, Virginia, VA 23284, USA
| | - Carlos Gustavo De Moraes
- Bernard and Shirlee Brown Glaucoma Research Laboratory, Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY 10032, USA
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Omodaka K, Fujioka S, An G, Udagawa T, Tsuda S, Shiga Y, Morishita S, Kikawa T, Pak K, Akiba M, Yokota H, Nakazawa T. Structural Characterization of Glaucoma Patients with Low Ocular Blood Flow. Curr Eye Res 2020; 45:1302-1308. [PMID: 32134693 DOI: 10.1080/02713683.2020.1736306] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Purpose: There is an unclear relationship between ocular blood flow (OBF) and the structural characteristics of the optic nerve head (ONH) in glaucoma, a multifactorial disease. This study used laser speckle flowgraphy (LSFG) to identify low-OBF glaucoma patients and investigated the ONH in these patients. Materials and Methods: In 533 eyes with glaucoma, we determined confounding factors for LSFG-measured OBF (tissue-area mean blur rate: MT) and corrected MT with a linear mixed-effects model (LMM). Structural ONH data (from fundus stereo photography), OCT data, and clinical characteristics were then compared in patients with corrected MT in the upper and lower quartiles using the LMM. Results: Single regression showed significant correlations between MT and age, spherical equivalent (SE), central corneal thickness (CCT), and a weighted count of retinal ganglion cells (wRGC), but not axial length or systemic blood pressure. Gender also significantly influenced MT; MT was corrected for these correlated factors and also glaucoma type with the LMM. The lower-quartile MT group had a significantly larger cup area and cup-disc area ratio and lower temporal quadrant circumpapillary retinal nerve fiber layer thickness (cpRNFLT) and macular ganglion cell complex (GCC) than the upper-quartile group. Conclusions: Low-OBF glaucoma patients were characterized by a larger cup-disc ratio, and higher susceptibility to damage in the temporal disc and the macular area.
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Affiliation(s)
- Kazuko Omodaka
- Department of Ophthalmology, Graduate School of Medicine, Tohoku University , Sendai, Japan
| | - Shunsuke Fujioka
- Department of Ophthalmology, Graduate School of Medicine, Tohoku University , Sendai, Japan
| | - Guangzhou An
- R&D Division, Topcon Corporation.,Cloud-Based Eye Disease Diagnosis Joint Research Team, Riken
| | | | - Satoru Tsuda
- Department of Ophthalmology, Graduate School of Medicine, Tohoku University , Sendai, Japan
| | - Yukihiro Shiga
- Department of Ophthalmology, Graduate School of Medicine, Tohoku University , Sendai, Japan.,Department of Ophthalmic Imaging and Information Analytics, Graduate School of Medicine, Tohoku University , Sendai, Japan
| | | | | | - Kyongsun Pak
- Division of Biostatistics, Center for Clinical Research, National Center for Child Health and Development , Tokyo, Japan
| | - Masahiro Akiba
- R&D Division, Topcon Corporation.,Cloud-Based Eye Disease Diagnosis Joint Research Team, Riken
| | - Hideo Yokota
- Cloud-Based Eye Disease Diagnosis Joint Research Team, Riken.,Image Processing Research Team, Riken
| | - Toru Nakazawa
- Department of Ophthalmology, Graduate School of Medicine, Tohoku University , Sendai, Japan.,Department of Ophthalmic Imaging and Information Analytics, Graduate School of Medicine, Tohoku University , Sendai, Japan
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Lee EJ, Han JC, Park DY, Kee C. A neuroglia-based interpretation of glaucomatous neuroretinal rim thinning in the optic nerve head. Prog Retin Eye Res 2020; 77:100840. [PMID: 31982595 DOI: 10.1016/j.preteyeres.2020.100840] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 01/02/2020] [Accepted: 01/13/2020] [Indexed: 12/14/2022]
Abstract
Neuroretinal rim thinning (NRR) is a characteristic glaucomatous optic disc change. However, the precise mechanism of the rim thinning has not been completely elucidated. This review focuses on the structural role of the glioarchitecture in the formation of the glaucomatous NRR thinning. The NRR is a glia-framed structure, with honeycomb geometry and mechanically reinforced astrocyte processes along the transverse plane. When neural damage selectively involves the neuron and spares the glia, the gross structure of the tissue is preserved. The disorganization and loss of the glioarchitecture are the two hallmarks of optic nerve head (ONH) remodeling in glaucoma that leads to the thinning of NRR tissue upon axonal loss. This is in contrast to most non-glaucomatous optic neuropathies with optic disc pallor where hypertrophy of the glioarchitecture is associated with the seemingly absent optic disc cupping. Arteritic anterior ischemic optic neuropathy is an exception where pan-necrosis of ONH tissue leads to NRR thinning. Milder ischemia indicates selective neuronal loss that spares glia in non-arteritic anterior ischemic optic neuropathy. The biological reason is the heterogeneous glial response determined by the site, type, and severity of the injury. The neuroglial interpretation explains how the cellular changes underlie the clinical findings. Updated understandings on glial responses illustrate the mechanical, microenvironmental, and microglial modulation of activated astrocytes in glaucoma. Findings relevant to the possible mechanism of the astrocyte death in advanced glaucoma are also emerging. Ultimately, a better understanding of glaucomatous glial response may lead to glia-targeting neuroprotection in the future.
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Affiliation(s)
- Eun Jung Lee
- Department of Ophthalmology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-Ro, Gangnam-gu, Seoul, 06351, South Korea
| | - Jong Chul Han
- Department of Ophthalmology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-Ro, Gangnam-gu, Seoul, 06351, South Korea
| | - Do Young Park
- Department of Ophthalmology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-Ro, Gangnam-gu, Seoul, 06351, South Korea
| | - Changwon Kee
- Department of Ophthalmology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-Ro, Gangnam-gu, Seoul, 06351, South Korea.
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Nascimento-Dos-Santos G, de-Souza-Ferreira E, Lani R, Faria CC, Araújo VG, Teixeira-Pinheiro LC, Vasconcelos T, Gonçalo T, Santiago MF, Linden R, Galina A, Petrs-Silva H. Neuroprotection from optic nerve injury and modulation of oxidative metabolism by transplantation of active mitochondria to the retina. Biochim Biophys Acta Mol Basis Dis 2020; 1866:165686. [PMID: 31953215 DOI: 10.1016/j.bbadis.2020.165686] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 01/07/2020] [Accepted: 01/10/2020] [Indexed: 01/16/2023]
Abstract
Mitochondrial dysfunctions are linked to a series of neurodegenerative human conditions, including Parkinson's disease, schizophrenia, optic neuropathies, and glaucoma. Recently, a series of studies have pointed mitotherapy - exogenous mitochondria transplant - as a promising way to attenuate the progression of neurologic disorders; however, the neuroprotective and pro-regenerative potentials of isolated mitochondria in vivo have not yet been elucidated. In this present work, we tested the effects of transplants of active (as well-coupled organelles were named), liver-isolated mitochondria on the survival of retinal ganglion cells and axonal outgrowth after optic nerve crush. Our data show that intravitreally transplanted, full active mitochondria incorporate into the retina, improve its oxidative metabolism and electrophysiological activity at 1 day after transplantation. Moreover, mitotherapy increases cell survival in the ganglion cell layer at 14 days, and leads to a higher number of axons extending beyond the injury site at 28 days; effects that are dependent on the organelles' structural integrity. Together, our findings support mitotherapy as a promising approach for future therapeutic interventions upon central nervous system damage.
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Affiliation(s)
- Gabriel Nascimento-Dos-Santos
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-901, Brazil.
| | - Eduardo de-Souza-Ferreira
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-901, Brazil.
| | - Rafael Lani
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-901, Brazil
| | - Caroline Coelho Faria
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-901, Brazil
| | - Victor Guedes Araújo
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-901, Brazil
| | | | - Taliane Vasconcelos
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-901, Brazil
| | - Thaís Gonçalo
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-901, Brazil
| | - Marcelo Felippe Santiago
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-901, Brazil
| | - Rafael Linden
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-901, Brazil
| | - Antonio Galina
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-901, Brazil.
| | - Hilda Petrs-Silva
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-901, Brazil.
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Yabana T, Sato K, Shiga Y, Himori N, Omodaka K, Nakazawa T. The relationship between glutathione levels in leukocytes and ocular clinical parameters in glaucoma. PLoS One 2019; 14:e0227078. [PMID: 31887133 PMCID: PMC6936795 DOI: 10.1371/journal.pone.0227078] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 12/10/2019] [Indexed: 12/12/2022] Open
Abstract
PURPOSE To investigate the effect of mitochondrial dysfunction on the autoregulation of blood flow, by measuring levels of glutathione, an indicator of mitochondrial dysfunction, in glaucoma patients. METHODS Fifty-six OAG patients and 21 age-matched controls underwent a blood assay. Mitochondrial function was measured according to the levels of total glutathione (t-GSH), reduced GSH (GSH), and oxidized GSH (GSSG, glutathione disulfide) in peripheral blood mononuclear cells. Ocular blood flow in the optic nerve head was assessed with laser speckle flowgraphy parameters, including acceleration time index (ATI). We determined correlations between these measurements and other clinical parameters. Furthermore, we investigated the association between glutathione levels and glaucoma with a logistic regression analysis. Finally, we calculated the area under the receiver operating characteristic (ROC) curve in order to determine the power of redox index (the log GSH/GSSG ratio) to distinguish the groups. RESULTS OAG patients demonstrated significantly higher GSSG levels and a lower redox index than the controls (p = 0.01, p = 0.01, respectively), but total GSH and reduced GSH levels were similar in the OAG subjects and controls (p = 0.80, p = 0.94, respectively). Additionally, redox index was significantly correlated with mean deviation (MD) of the visual field (r = 0.29, p = 0.03) and ATI (r = -0.30, p = 0.03). Multiple linear regression analysis showed that redox index contributed to MD (p = 0.02) and ATI (p = 0.04). The receiver operating characteristic curve (AUC) analysis suggested that redox index could differentiate between control eyes and eyes with glaucoma (AUC; 0.70: 95% interval; 0.57-0.84). The cutoff point for redox index to maximize its sensitivity and specificity was 2.0 (sensitivity: 91.1%, specificity: 42.9%). CONCLUSIONS These results suggest that redox index is lower in OAG patients than in controls. Thus, it is possible that mitochondrial dysfunction contributes to glaucoma pathogenesis by causing vascular alterations.
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Affiliation(s)
- Takeshi Yabana
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Kota Sato
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Japan
- Collaborative Program for Ophthalmic Drug Discovery, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Yukihiro Shiga
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Japan
- Department of Ophthalmic Imaging and Information Analytics, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Noriko Himori
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Kazuko Omodaka
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Toru Nakazawa
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Japan
- Collaborative Program for Ophthalmic Drug Discovery, Tohoku University Graduate School of Medicine, Sendai, Japan
- Department of Ophthalmic Imaging and Information Analytics, Tohoku University Graduate School of Medicine, Sendai, Japan
- Department of Retinal Disease Control, Tohoku University Graduate School of Medicine, Sendai, Japan
- Department of Advanced Ophthalmic Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan
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Karaarslan C. Leber's Hereditary Optic Neuropathy as a Promising Disease for Gene Therapy Development. Adv Ther 2019; 36:3299-3307. [PMID: 31605306 PMCID: PMC6860503 DOI: 10.1007/s12325-019-01113-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Indexed: 12/13/2022]
Abstract
Leber's hereditary optic neuropathy (LHON) is a relatively common, rapidly progressing inherited optic neuropathy wherein LHON-affected eyes undergo optic nerve atrophy due to retinal ganglion cell (RGC) loss. It is a maternally inherited (or sporadic) mitochondrial disorder caused primarily by mutations in genes that encode components of respiratory complex (RC)1 in mitochondria. Mitochondrial deficiency of RC1 compromises ATP production and oxidative stress management in RGCs. The most common LHON-causing mutations are 11778G>A, 3460G>A, and 14484T>C point mutations in MT-ND4, MT-ND1, and MT-ND6. The unusually high mitochondrial load of RGCs makes them particularly sensitive to these mutations. Patients with LHON may be prescribed ubiquinone (a component of RC3) or idebenone, a ubiquinone analogue with enhanced bioavailability to act downstream of RC1. The challenge of accessing the inner mitochondrial membrane with gene therapy for LHON, and other mitochondrial diseases, may be overcome by incorporation of a specific mitochondrion-targeting sequence (MTS) that enables allotropic expression of a nucleus-transcribed ND4 transgene. Because LHON penetrance is incomplete among carriers of the aforementioned mutations, identification of environmental factors, such as heavy smoking, that interact with genetics in the phenotypic expression of LHON may be helpful toward preventing or delaying disease development. LHON has become a model for mitochondrial and neurogenerative diseases owing to it having a clearly identified genetic cause and its early onset and rapid progression characteristics. Hence, LHON studies and genetic treatment advances may inform research of other diseases.
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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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Visual pathways evaluation in Kearns Sayre syndrome: a diffusion tensor imaging study. Neuroradiology 2019; 62:241-249. [PMID: 31680196 DOI: 10.1007/s00234-019-02302-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 10/04/2019] [Indexed: 01/13/2023]
Abstract
PURPOSE Kearns Sayre syndrome (KSS) is a mitochondrial disorder characterized by development of visual impairment. Electroretinogram (ERG) and visual evoked potentials are not able to provide topographical information of optic damage. The purpose of this study was to explore retrochiasmatic optic pathway alteration in KSS with diffusion tractographic analysis and to compare it with different tracts. METHODS DTI from 8 KSS subjects (14.7 years) and 10 healthy controls (HC) were acquired on a 3T scanner. Optic radiations (OR), optic tracts (OT), inferior frontooccipital fasciculus (IFOF) and corticospinal tract (CST) were reconstructed with probabilistic tractography. Fractional anisotropy (FA), apparent diffusion coefficient (ADC), radial (RD), and axial diffusivity (AD) were calculated, evaluating group differences. T test on diffusion parameters identified significantly different track portions among cohorts. RESULTS All patients had optic pathway alterations at electrophysiological examination. Significant lower FA were found in OT, IFOF, and CST of KSS group. RD was significantly higher in bilateral OR, IFOF, CST, and right OT, while ADC was higher in bilateral OR and CST. RD values were higher in the proximal and distal portion of OR bilaterally and in the distal portion of right OT, while widespread differences were found in IFOF and CST. No significant differences were found for AD. FA profiles analysis demonstrated significant differences between groups in several regions of OT, IFOF, and CST, while ADC assessment revealed spread differences in OR and CST. CONCLUSIONS DTI evaluation of retrochiasmatic tracks may represent a useful tool to topographically investigate retrochiasmatic visual impairment in KSS.
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Ma Z, Jiang H, Wang J. Clinical analysis of severe visual loss caused by inhalational methanol poisoning in a chronic process with acute onset:a retrospective clinical analysis. BMC Ophthalmol 2019; 19:124. [PMID: 31174513 PMCID: PMC6554876 DOI: 10.1186/s12886-019-1127-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Accepted: 05/20/2019] [Indexed: 11/16/2022] Open
Abstract
Background To analyze the clinical features and prognosis of the visual loss resulted from inhalational methanol poisoning in 8 Chinese patients. Methods Eight consecutive patients seen at the Beijing Tongren Hospital of Capital Medical University, Beijing, China between January 2003 to August 2017, with complains of vision loss in both eyes, identified as inhalational methanol poisoning. Detailed medical history was extracted. All patients underwent optic nerve and brain magnetic resonance imaging (MRI) scan, laboratory tests, and visual function analysis. Treatment protocols were large dosage of methylprednisolone and B vitamins over 3 months. Patients were seen at 3-month intervals until a year. Results Eight patients with optic neuropathy caused by inhalation toxicity of methanol were under observation, whose methanol-contact time spans were form 4 days to 5 years for occupational exposure. All the patients had acute onset, transient systemic symptoms on early stage, both eyes involved with severe visual impairment (visual acuity 0.1 or even worse). Retrobulbar optic nerves (ONs) were the major sites involved. Optic nerve MRI scan showed increased signal of bilateral ONs in the orbit and the canal parts, with enhancement. After treatment, the visual function of these patients got improved in different degree in a year follow-up, but not satisfactorily. Conclusions Inhalational methanol toxicity may lead to serious damage to ON in a process of chronic intoxication with acute attack, and with poor prognosis.
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Affiliation(s)
- Zhonghua Ma
- Department of Neurology, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730, China
| | - Hanqiu Jiang
- Department of Neurology, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730, China
| | - Jiawei Wang
- Department of Neurology, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730, China.
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Lozano DC, Choe TE, Cepurna WO, Morrison JC, Johnson EC. Early Optic Nerve Head Glial Proliferation and Jak-Stat Pathway Activation in Chronic Experimental Glaucoma. Invest Ophthalmol Vis Sci 2019; 60:921-932. [PMID: 30835784 PMCID: PMC6402265 DOI: 10.1167/iovs.18-25700] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 01/25/2019] [Indexed: 12/18/2022] Open
Abstract
PURPOSE We previously reported increased expression of cell proliferation and Jak-Stat pathway-related genes in chronic experimental glaucoma model optic nerve heads (ONH) with early, mild injury. Here, we confirm these observations by localizing, identifying, and quantifying ONH cellular proliferation and Jak-Stat pathway activation in this model. METHODS Chronic intraocular pressure (IOP) elevation was achieved via outflow pathway sclerosis. After 5 weeks, ONH longitudinal sections were immunolabeled with proliferation and cell-type markers to determine nuclear densities in the anterior (unmyelinated) and transition (partially myelinated) ONH. Nuclear pStat3 labeling was used to detect Jak-Stat pathway activation. Nuclear density differences between control ONH (uninjected) and ONH with either early or advanced injury (determined by optic nerve injury grading) were identified by ANOVA. RESULTS Advanced injury ONH had twice the nuclear density (P < 0.0001) of controls and significantly greater astrocyte density in anterior (P = 0.0001) and transition (P = 0.006) ONH regions. An increased optic nerve injury grade positively correlated with increased microglia/macrophage density in anterior and transition ONH (P < 0.0001, both). Oligodendroglial density was unaffected. In glaucoma model ONH, 80% of anterior and 66% of transition region proliferating cells were astrocytes. Nuclear pStat3 labeling significantly increased in early injury anterior ONH, and 95% colocalized with astrocytes. CONCLUSIONS Astrocytes account for the majority of proliferating cells, contributing to a doubled nuclear density in advanced injury ONH. Jak-Stat pathway activation is apparent in the early injury glaucoma model ONH. These data confirm dramatic astrocyte cell proliferation and early Jak-Stat pathway activation in ONH injured by elevated IOP.
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Affiliation(s)
- Diana C. Lozano
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Tiffany E. Choe
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - William O. Cepurna
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - John C. Morrison
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Elaine C. Johnson
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
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Inoue-Yanagimachi M, Himori N, Sato K, Kokubun T, Asano T, Shiga Y, Tsuda S, Kunikata H, Nakazawa T. Association between mitochondrial DNA damage and ocular blood flow in patients with glaucoma. Br J Ophthalmol 2018; 103:1060-1065. [DOI: 10.1136/bjophthalmol-2018-312356] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 07/24/2018] [Accepted: 08/13/2018] [Indexed: 02/03/2023]
Abstract
Background/AimsWe determined the relationship between tissue mean blur rate (MT) and mitochondrial dysfunction, represented by the mitochondrial/nuclear DNA (mtDNA/nDNA) ratio. We also investigated the usefulness of these biomarkers.MethodsWe assessed ocular blood flow in 123 eyes of 123 patients with open-angle glaucoma (OAG) and 37 control eyes of 37 healthy subjects by measuring MT in the optic nerve head with laser speckle flowgraphy. We measured mtDNA and nDNA with PCR, calculated the mtDNA/nDNA ratio and compared this ratio with MT using Spearman’s rank test. We used multiple regression analysis to further investigate the association between MT and glaucoma in the most severe group.ResultsThe control and the patients with glaucoma had significant differences in the mtDNA/nDNA ratio, circumpapillary retinal nerve fibre layer thickness and MT. There was no significant relationship between the mtDNA/nDNA ratio and MT in patients with OAG overall or the female patients with OAG, but there was a significant relationship between the mtDNA/nDNA ratio and MT, temporal-MT and superior-MT in male patients with severe OAG (r=−0.46, p=0.03; r=−0.51, p=0.02; r=−0.61, p<0.01, respectively). Furthermore, we found that the mtDNA/nDNA ratio was an independent contributor to temporal-MT and superior-MT in these patients (p<0.01 and p=0.03, respectively).ConclusionWe found that there was a significant relationship between the mtDNA/nDNA ratio and MT in male patients with severe OAG, suggesting that the mtDNA/nDNA ratio may be a new biomarker in glaucoma and may help research on the vulnerability of these patients to mitochondrial dysfunction.
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Zhu MM, Lai JSM, Choy BNK, Shum JWH, Lo ACY, Ng ALK, Chan JCH, So KF. Physical exercise and glaucoma: a review on the roles of physical exercise on intraocular pressure control, ocular blood flow regulation, neuroprotection and glaucoma-related mental health. Acta Ophthalmol 2018; 96:e676-e691. [PMID: 29338126 DOI: 10.1111/aos.13661] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2017] [Accepted: 11/06/2017] [Indexed: 12/13/2022]
Abstract
The benefits of physical exercise on health and well-being have been studied in a wide range of systemic and ocular diseases, including glaucoma, a progressive optic neuropathy characterized by accelerated apoptosis of retinal ganglion cells (RGCs). Elevated intraocular pressure (IOP) and insufficient ocular perfusion have been postulated to be the two main theories in glaucoma development and progression. The effects of exercise in these two aspects have been demonstrated by numerous researches. A review in 2009 focusing on these two theories concluded that exercise results in transient IOP reduction but an inconsistent elevation in ocular perfusion. However, the majority of the studies had been conducted in healthy subjects. Over the past decade, technological advancement has brought forth new and more detailed evidence regarding the effects of exercise. Moreover, the neuroprotective effect of exercise by upregulation of neurotrophin and enhancement of mitochondrial function has been a focus of interest. Apart from visual impairment, the mental health issues in patients with glaucoma, which include anxiety and depression, should also be addressed. In this review, we mainly focus on publications from the recent years, so as to provide a comprehensive review on the impact of physical exercise on IOP, ocular perfusion, neuroprotection and mental health in patients with glaucoma.
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Affiliation(s)
- Ming Ming Zhu
- Department of Ophthalmology; LKS Faculty of Medicine; The University of Hong Kong; Hong Kong SAR China
| | - Jimmy Shiu Ming Lai
- Department of Ophthalmology; LKS Faculty of Medicine; The University of Hong Kong; Hong Kong SAR China
| | - Bonnie Nga Kwan Choy
- Department of Ophthalmology; LKS Faculty of Medicine; The University of Hong Kong; Hong Kong SAR China
| | - Jennifer Wei Huen Shum
- Department of Ophthalmology; LKS Faculty of Medicine; The University of Hong Kong; Hong Kong SAR China
| | - Amy Cheuk Yin Lo
- Department of Ophthalmology; LKS Faculty of Medicine; The University of Hong Kong; Hong Kong SAR China
| | - Alex Lap Ki Ng
- Department of Ophthalmology; LKS Faculty of Medicine; The University of Hong Kong; Hong Kong SAR China
| | - Jonathan Cheuk Hung Chan
- Department of Ophthalmology; LKS Faculty of Medicine; The University of Hong Kong; Hong Kong SAR China
| | - Kwok Fai So
- Department of Ophthalmology; LKS Faculty of Medicine; The University of Hong Kong; Hong Kong SAR China
- School of Biomedical Sciences; LKS Faculty of Medicine; The University of Hong Kong; Hong Kong SAR China
- State Key Laboratory of Brain and Cognitive Sciences; The University of Hong Kong; Hong Kong SAR China
- GHM Institute of CNS Regeneration; Ministry of Education CNS Regeneration Collaborative Joint Laboratory; Jinan University; Guangzhou China
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Carelli V, La Morgia C, Ross-Cisneros FN, Sadun AA. Optic neuropathies: the tip of the neurodegeneration iceberg. Hum Mol Genet 2018; 26:R139-R150. [PMID: 28977448 PMCID: PMC5886475 DOI: 10.1093/hmg/ddx273] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 07/10/2017] [Indexed: 01/06/2023] Open
Abstract
The optic nerve and the cells that give origin to its 1.2 million axons, the retinal ganglion cells (RGCs), are particularly vulnerable to neurodegeneration related to mitochondrial dysfunction. Optic neuropathies may range from non-syndromic genetic entities, to rare syndromic multisystem diseases with optic atrophy such as mitochondrial encephalomyopathies, to age-related neurodegenerative diseases such as Alzheimer’s and Parkinson’s disease where optic nerve involvement has, until recently, been a relatively overlooked feature. New tools are available to thoroughly investigate optic nerve function, allowing unparalleled access to this part of the central nervous system. Understanding the molecular pathophysiology of RGC neurodegeneration and optic atrophy, is key to broadly understanding the pathogenesis of neurodegenerative disorders, for monitoring their progression in describing the natural history, and ultimately as outcome measures to evaluate therapies. In this review, the different layers, from molecular to anatomical, that may contribute to RGC neurodegeneration and optic atrophy are tackled in an integrated way, considering all relevant players. These include RGC dendrites, cell bodies and axons, the unmyelinated retinal nerve fiber layer and the myelinated post-laminar axons, as well as olygodendrocytes and astrocytes, looked for unconventional functions. Dysfunctional mitochondrial dynamics, transport, homeostatic control of mitobiogenesis and mitophagic removal, as well as specific propensity to apoptosis may target differently cell types and anatomical settings. Ultimately, we can envisage new investigative approaches and therapeutic options that will speed the early diagnosis of neurodegenerative diseases and their cure.
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Affiliation(s)
- Valerio Carelli
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy.,Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
| | - Chiara La Morgia
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy.,Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
| | | | - Alfredo A Sadun
- Doheny Eye Institute, Los Angeles, CA 90033, USA.,Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
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Ruiz-Pesini E, Emperador S, López-Gallardo E, Hernández-Ainsa C, Montoya J. Increasing mtDNA levels as therapy for mitochondrial optic neuropathies. Drug Discov Today 2018; 23:493-498. [DOI: 10.1016/j.drudis.2018.01.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 11/15/2017] [Accepted: 01/07/2018] [Indexed: 10/18/2022]
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Chidlow G, Wood JPM, Casson RJ. Investigations into Hypoxia and Oxidative Stress at the Optic Nerve Head in a Rat Model of Glaucoma. Front Neurosci 2017; 11:478. [PMID: 28883787 PMCID: PMC5573812 DOI: 10.3389/fnins.2017.00478] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Accepted: 08/11/2017] [Indexed: 01/03/2023] Open
Abstract
The vascular hypothesis of glaucoma proposes that retinal ganglion cell axons traversing the optic nerve head (ONH) undergo oxygen and nutrient insufficiency as a result of compromised local blood flow, ultimately leading to their degeneration. To date, evidence for the hypothesis is largely circumstantial. Herein, we made use of an induced rat model of glaucoma that features reproducible and widespread axonal transport disruption at the ONH following chronic elevation of intraocular pressure. If vascular insufficiency plays a role in the observed axonal transport failure, there should exist a physical signature at this time point. Using a range of immunohistochemical and molecular tools, we looked for cellular events indicative of vascular insufficiency, including the presence of hypoxia, upregulation of hypoxia-inducible, or antioxidant-response genes, alterations to antioxidant enzymes, increased formation of superoxide, and the presence of oxidative stress. Our data show that ocular hypertension caused selective hypoxia within the laminar ONH in 11/13 eyes graded as either medium or high for axonal transport disruption. Hypoxia was always present in areas featuring injured axons, and, the greater the abundance of axonal transport disruption, the greater the likelihood of a larger hypoxic region. Nevertheless, hypoxic regions were typically focal and were not necessarily evident in sections taken deeper within the same ONH, while disrupted axonal transport was frequently encountered without any discernible hypoxia. Ocular hypertension caused upregulation of heme oxygenase-1—an hypoxia-inducible and redox-sensitive enzyme—in ONH astrocytes. The distribution and abundance of heme oxygenase-1 closely matched that of axonal transport disruption, and encompassed hypoxic regions and their immediate penumbra. Ocular hypertension also caused upregulations in the iron-regulating protein ceruloplasmin, the anaerobic glycolytic enzyme lactate dehydrogenase, and the transcription factors cFos and p-cJun. Moreover, ocular hypertension increased the generation of superoxide radicals in the retina and ONH, as well as upregulating the active subunit of the superoxide-generating enzyme NADPH oxidase, and invoking modest alterations to antioxidant-response enzymes. The results of this study provide further indirect support for the hypothesis that reduced blood flow to the ONH contributes to axonal injury in glaucoma.
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Affiliation(s)
- Glyn Chidlow
- Ophthalmic Research Laboratories, Discipline of Ophthalmology and Visual Sciences, University of AdelaideAdelaide, SA, Australia
| | - John P M Wood
- Ophthalmic Research Laboratories, Discipline of Ophthalmology and Visual Sciences, University of AdelaideAdelaide, SA, Australia
| | - Robert J Casson
- Ophthalmic Research Laboratories, Discipline of Ophthalmology and Visual Sciences, University of AdelaideAdelaide, SA, Australia
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Fortune B, Reynaud J, Hardin C, Wang L, Sigal IA, Burgoyne CF. Experimental Glaucoma Causes Optic Nerve Head Neural Rim Tissue Compression: A Potentially Important Mechanism of Axon Injury. Invest Ophthalmol Vis Sci 2017; 57:4403-11. [PMID: 27564522 PMCID: PMC5016000 DOI: 10.1167/iovs.16-20000] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Purpose We tested the hypothesis that experimental glaucoma (EG) results in greater thinning of the optic nerve head (ONH) neural rim tissue than the peripapillary retinal nerve fiber layer (RNFL) tissue. Methods Longitudinal spectral-domain optical coherence tomography (SDOCT) imaging of the ONH and peripapillary RNFL was performed every other week under manometric IOP control (10 mm Hg) in 51 nonhuman primates (NHP) during baseline and after induction of unilateral EG. The ONH parameter minimum rim area (MRA) was derived from 80 radial B-scans centered on the ONH; RNFL cross-sectional area (RNFLA) from a peripapillary circular B-scan with 12° diameter. Results In control eyes, MRA was 1.00 ± 0.19 mm2 at baseline and 1.00 ± 0.19 mm2 at the final session (P = 0.77), while RNFLA was 0.95 ± 0.09 and 0.95 ± 0.10 mm2, respectively (P = 0.96). In EG eyes, MRA decreased from 1.00 ± 0.19 mm2 at baseline to 0.63 ± 0.21 mm2 at the final session (P < 0.0001), while RNFLA decreased from 0.95 ± 0.09 to 0.74 ± 0.19 mm2, respectively (P < 0.0001). Thus, MRA decreased by 36.4 ± 20.6% in EG eyes, significantly more than the decrease in RNFLA (21.7 ± 19.4%, P < 0.0001). Other significant changes in EG eyes included increased Bruch's membrane opening (BMO) nonplanarity (P < 0.05), decreased BMO aspect ratio (P < 0.0001), and decreased MRA angle (P < 0.001). Bruch's membrane opening area did not change from baseline in either control or EG eyes (P = 0.27, P = 0.15, respectively). Conclusions Optic nerve head neural rim tissue thinning exceeded peripapillary RNFL thinning in NHP EG. These results support the hypothesis that axon bundles are compressed transversely within the ONH rim along with glaucomatous deformation of connective tissues.
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Affiliation(s)
- Brad Fortune
- Discoveries in Sight Research Laboratories Devers Eye Institute and Legacy Research Institute, Legacy Health, Portland, Oregon, United States
| | - Juan Reynaud
- Discoveries in Sight Research Laboratories Devers Eye Institute and Legacy Research Institute, Legacy Health, Portland, Oregon, United States
| | - Christy Hardin
- Discoveries in Sight Research Laboratories Devers Eye Institute and Legacy Research Institute, Legacy Health, Portland, Oregon, United States
| | - Lin Wang
- Discoveries in Sight Research Laboratories Devers Eye Institute and Legacy Research Institute, Legacy Health, Portland, Oregon, United States
| | - Ian A Sigal
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Claude F Burgoyne
- Discoveries in Sight Research Laboratories Devers Eye Institute and Legacy Research Institute, Legacy Health, Portland, Oregon, United States
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Kamel K, Farrell M, O'Brien C. Mitochondrial dysfunction in ocular disease: Focus on glaucoma. Mitochondrion 2017; 35:44-53. [PMID: 28499981 DOI: 10.1016/j.mito.2017.05.004] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 03/08/2017] [Accepted: 05/08/2017] [Indexed: 12/21/2022]
Abstract
Mitochondrial dysfunction commonly presents with ocular findings as a part of a systemic disorder. These ophthalmic manifestations can be the first sign of a mitochondrial abnormality, which highlights the key role of a comprehensive ophthalmic assessment. On the other hand, a number of visually disabling genetic and acquired eye diseases with no curative treatment show abnormal mitochondrial function. Recent advances in mitochondrial research have improved our understanding of previously unexplained ocular disorders utilising better diagnostic approaches. Further studies on mitochondrial dysfunction and novel modalities of treatment will help to improve outcomes of these conditions. In this review article we discuss the clinical picture of common mitochondrial-related eye diseases, diagnostic approaches and possible treatment options including a very recent interesting report about gene therapy, with a particular focus on glaucoma.
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Affiliation(s)
- Khalid Kamel
- Institute of Ophthalmology, Mater Misericordiae University Hospital, Dublin, Ireland
| | | | - Colm O'Brien
- Institute of Ophthalmology, Mater Misericordiae University Hospital, Dublin, Ireland.
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Cwerman-Thibault H, Lechauve C, Augustin S, Roussel D, Reboussin É, Mohammad A, Degardin-Chicaud J, Simonutti M, Liang H, Brignole-Baudouin F, Maron A, Debeir T, Corral-Debrinski M. Neuroglobin Can Prevent or Reverse Glaucomatous Progression in DBA/2J Mice. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2017; 5:200-220. [PMID: 28540323 PMCID: PMC5430497 DOI: 10.1016/j.omtm.2017.04.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 04/21/2017] [Indexed: 01/12/2023]
Abstract
Mitochondrial dysfunction is responsible for hereditary optic neuropathies. We wished to determine whether preserving mitochondrial bioenergetics could prevent optic neuropathy in a reliable model of glaucoma. DBA/2J mice exhibit elevated intraocular pressure, progressive degeneration of their retinal ganglion cells, and optic neuropathy that resembles glaucoma. We established that glaucoma in these mice is directly associated with mitochondrial dysfunction: respiratory chain activity was compromised in optic nerves 5 months before neuronal loss began, and the amounts of some mitochondrial proteins were reduced in retinas of glaucomatous mice. One of these proteins is neuroglobin, which has a neuroprotective function. Therefore, we investigated whether gene therapy aimed at restoring neuroglobin levels in the retina via ocular administration of an adeno-associated viral vector could reduce neuronal degeneration. The approach of treating 2-month-old mice impeded glaucoma development: few neurons died and respiratory chain activity and visual cortex activity were comparable to those in young, asymptomatic mice. When the treatment was performed in 8-month-old mice, the surviving neurons acquired new morphologic and functional properties, leading to the preservation of visual cortex activity and respiratory chain activity. The beneficial effects of neuroglobin in DBA/2J retinas confirm this protein to be a promising candidate for treating glaucoma.
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Affiliation(s)
- Hélène Cwerman-Thibault
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012 Paris, France
- PROTECT, INSERM, Université Paris Diderot, Sorbonne Paris Cité, 75019 Paris, France
| | - Christophe Lechauve
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012 Paris, France
- Department of Hematology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Sébastien Augustin
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012 Paris, France
| | - Delphine Roussel
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012 Paris, France
- Institut du Cerveau et de la Moelle Épinière, Hôpital Pitié Salpêtrière, 75013 Paris, France
| | - Élodie Reboussin
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012 Paris, France
| | - Ammara Mohammad
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012 Paris, France
- Genomic Paris Centre, Institut de Biologie de l’Ecole normale supérieure, 46 rue d’Ulm, 75230 Paris, France
| | - Julie Degardin-Chicaud
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012 Paris, France
| | - Manuel Simonutti
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012 Paris, France
| | - Hong Liang
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012 Paris, France
- CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DHOS CIC, 28 rue de Charenton, 75012 Paris, France
| | - Françoise Brignole-Baudouin
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012 Paris, France
| | - Anne Maron
- Sanofi-Aventis, 94400 Vitry-sur-Seine, France
| | - Thomas Debeir
- Departments of Evaluation and Expertise Strategy, Science Policy and External Innovation, Sanofi, 75008 Paris, France
| | - Marisol Corral-Debrinski
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012 Paris, France
- PROTECT, INSERM, Université Paris Diderot, Sorbonne Paris Cité, 75019 Paris, France
- Corresponding author: Marisol Corral-Debrinski, PROTECT, INSERM (UMR1141), Université Paris Diderot, Sorbonne Paris Cité, 48 Boulevard Sérurier, 75019 Paris, France.
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Kimball EC, Pease ME, Steinhart MR, Oglesby EN, Pitha I, Nguyen C, Quigley HA. A mouse ocular explant model that enables the study of living optic nerve head events after acute and chronic intraocular pressure elevation: Focusing on retinal ganglion cell axons and mitochondria. Exp Eye Res 2017; 160:106-115. [PMID: 28414059 DOI: 10.1016/j.exer.2017.04.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 01/03/2017] [Accepted: 04/09/2017] [Indexed: 11/16/2022]
Abstract
We developed an explant model of the mouse eye and optic nerve that facilitates the study of retinal ganglion cell axons and mitochondria in the living optic nerve head (ONH) in an ex vivo environment. Two transgenic mouse strains were used, one expressing yellow fluorescent protein in selected axons and a second strain expressing cyan fluorescent protein in all mitochondria. We viewed an explanted mouse eye and optic nerve by laser scanning microscopy at and behind the ONH, the site of glaucoma injury. Explants from previously untreated mice were studied with the intraocular pressure (IOP) set artificially at normal or elevated levels for several hours. Explants were also studied from eyes that had undergone chronic IOP elevation from 14 h to 6 weeks prior to ex vivo study. Image analysis in static images and video of individual mitochondria or axonal structure determined effects of acute and chronic IOP elevation. At normal IOP, fluorescent axonal structure was stable for up to 3 h under ex vivo conditions. After chronic IOP elevation, axonal integrity index values indicated fragmentation of axon structure in the ONH. In mice with fluorescent mitochondria, the normal density decreased with distance behind the ONH by 45% (p = 0.002, t-test). Density increased with prior chronic IOP elevation to 21,300 ± 4176 mitochondria/mm2 compared to control 16,110 ± 3159 mitochondria/mm2 (p = 0.025, t-test), but did not increase significantly after 4 h, acute IOP elevation (1.5% decrease in density, p = 0.83, t-test). Mean normal mitochondrial length of 2.3 ± 1.4 μm became 13% smaller after 4 h of IOP elevation ex vivo compared to baseline (p = 0.015, t-test, N-10). Normal mitochondrial speed of movement was significantly slower in the anterograde direction (towards the brain) than retrograde, but there were more mitochondria in motion and traveling longer lengths in anterograde direction. The percent of mitochondria in motion decreased by >50% with acute IOP increase to 30 mm Hg after 60 min. A new ocular explant model implemented with eyes from transgenic mice with fluorescent cellular components provided real time measurement of the early events in experimental glaucoma and quantitative outcomes for neuroprotection therapy experiments.
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Affiliation(s)
- Elizabeth C Kimball
- From the Glaucoma Center of Excellence, Wilmer Ophthalmological Institute, Johns Hopkins University, Baltimore, MD, USA.
| | - Mary E Pease
- From the Glaucoma Center of Excellence, Wilmer Ophthalmological Institute, Johns Hopkins University, Baltimore, MD, USA
| | - Matthew R Steinhart
- From the Glaucoma Center of Excellence, Wilmer Ophthalmological Institute, Johns Hopkins University, Baltimore, MD, USA
| | - Ericka N Oglesby
- From the Glaucoma Center of Excellence, Wilmer Ophthalmological Institute, Johns Hopkins University, Baltimore, MD, USA
| | - Ian Pitha
- From the Glaucoma Center of Excellence, Wilmer Ophthalmological Institute, Johns Hopkins University, Baltimore, MD, USA
| | - Cathy Nguyen
- From the Glaucoma Center of Excellence, Wilmer Ophthalmological Institute, Johns Hopkins University, Baltimore, MD, USA
| | - Harry A Quigley
- From the Glaucoma Center of Excellence, Wilmer Ophthalmological Institute, Johns Hopkins University, Baltimore, MD, USA
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