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Short-term increases in transient receptor potential vanilloid-1 mediate stress-induced enhancement of neuronal excitation. J Neurosci 2015; 34:15369-81. [PMID: 25392504 DOI: 10.1523/jneurosci.3424-14.2014] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Progression of neurodegeneration in disease and injury is influenced by the response of individual neurons to stressful stimuli and whether this response includes mechanisms to counter declining function. Transient receptor potential (TRP) cation channels transduce a variety of disease-relevant stimuli and can mediate diverse stress-dependent changes in physiology, both presynaptic and postsynaptic. Recently, we demonstrated that knock-out or pharmacological inhibition of the TRP vanilloid-1 (TRPV1) capsaicin-sensitive subunit accelerates degeneration of retinal ganglion cell neurons and their axons with elevated ocular pressure, the critical stressor in the most common optic neuropathy, glaucoma. Here we probed the mechanism of the influence of TRPV1 on ganglion cell survival in mouse models of glaucoma. We found that induced elevations of ocular pressure increased TRPV1 in ganglion cells and its colocalization at excitatory synapses to their dendrites, whereas chronic elevation progressively increased ganglion cell Trpv1 mRNA. Enhanced TRPV1 expression in ganglion cells was transient and supported a reversal of the effect of TRPV1 on ganglion cells from hyperpolarizing to depolarizing, which was also transient. Short-term enhancement of TRPV1-mediated activity led to a delayed increase in axonal spontaneous excitation that was absent in ganglion cells from Trpv1(-/-) retina. In isolated ganglion cells, pharmacologically activated TRPV1 mobilized to discrete nodes along ganglion cell dendrites that corresponded to sites of elevated Ca(2+). These results suggest that TRPV1 may promote retinal ganglion cell survival through transient enhancement of local excitation and axonal activity in response to ocular stress.
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202
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Lambert WS, Carlson BJ, van der Ende AE, Shih G, Dobish JN, Calkins DJ, Harth E. Nanosponge-Mediated Drug Delivery Lowers Intraocular Pressure. Transl Vis Sci Technol 2015; 4:1. [PMID: 25599009 DOI: 10.1167/tvst.4.1.1] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Accepted: 11/11/2014] [Indexed: 02/06/2023] Open
Abstract
PURPOSE We examined the efficacy of an extended-release drug delivery system, nanosponge (NS) encapsulated compounds, administered intravitreally to lower intraocular pressure (IOP) in mice. METHODS Bilateral ocular hypertension was induced in mice by injecting microbeads into the anterior chamber. Hypertensive mice received NS loaded with ocular hypotensive drugs via intravitreal injection and IOP was monitored. Retinal deposition and retinal ganglion cell (RGC) uptake of Neuro-DiO were examined following intravitreal injection of Neuro-DiO-NS using confocal microscopy. RESULTS Brimonidine-loaded NS lowered IOP 12% to 30% for up to 6 days (P < 0.02), whereas travoprost-NS lowered IOP 19% to 29% for up to 4 days (P < 0.02) compared to saline injection. Three bimatoprost NS were tested: a 400-nm NS and two 700-nm NS with amorphous (A-NS) or amorphous/crystalline (AC-NS) crosslinkers. A single injection of 400 nm NS lowered IOP 24% to 33% for up to 17 days compared to saline, while A-NS and AC-NS lowered IOP 22% to 32% and 18% to 26%, respectively, for up to 32 days (P < 0.046). Over time retinal deposition of Neuro-DiO increased from 19% to 71%; Neuro-DiO released from NS was internalized by RGCs. CONCLUSIONS A single injection of NS can effectively deliver ocular hypotensive drugs in a linear and continuous manner for up to 32 days. Also, NS may be effective at targeting RGCs, the neurons that degenerate in glaucoma. TRANSLATIONAL RELEVANCE Patient compliance is a major issue in glaucoma. The use of NS to deliver a controlled, sustained release of therapeutics could drastically reduce the number of patients that progress to vision loss in this disease.
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Affiliation(s)
- Wendi S Lambert
- The Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Brian J Carlson
- The Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, USA
| | | | - Grace Shih
- The Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Julia N Dobish
- Vanderbilt Brain Institute, Vanderbilt University Medical Center, Nashville, TN, USA
| | - David J Calkins
- The Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, USA ; Vanderbilt Brain Institute, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Eva Harth
- Department of Chemistry, Vanderbilt University, Nashville, TN, USA
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Ortín-Martínez A, Salinas-Navarro M, Nadal-Nicolás FM, Jiménez-López M, Valiente-Soriano FJ, García-Ayuso D, Bernal-Garro JM, Avilés-Trigueros M, Agudo-Barriuso M, Villegas-Pérez MP, Vidal-Sanz M. Laser-induced ocular hypertension in adult rats does not affect non-RGC neurons in the ganglion cell layer but results in protracted severe loss of cone-photoreceptors. Exp Eye Res 2015; 132:17-33. [PMID: 25576772 DOI: 10.1016/j.exer.2015.01.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 11/19/2014] [Accepted: 01/07/2015] [Indexed: 01/09/2023]
Abstract
To investigate the long-term effects of laser-photocoagulation (LP)-induced ocular hypertension (OHT) in the innermost and outermost (outer-nuclear and outer segment)-retinal layers (ORL). OHT was induced in the left eye of adult rats. To investigate the ganglion cell layer (GCL) wholemounts were examined at 1, 3 or 6 months using Brn3a-immunodetection to identify retinal ganglion cells (RGCs) and DAPI-staining to detect all nuclei in this layer. To study the effects of LP on the ORL up to 6 months, retinas were: i) fresh extracted to quantify the levels of rod-, S- and L-opsin; ii) cut in cross-sections for morphometric analysis, or; iii) prepared as wholemounts to quantify and study retinal distributions of entire populations of RGCs (retrogradely labeled with fluorogold, FG), S- and L-cones (immunolabeled). OHT resulted in wedge-like sectors with their apex on the optic disc devoid of Brn3a(+)RGCs but with large numbers of DAPI(+)nuclei. The levels of all opsins diminished by 2 weeks and further decreased to 20% of basal-levels by 3 months. Cross-sections revealed focal areas of ORL degeneration. RGC survival at 15 days represented approximately 28% and did not change with time, whereas the S- and L-cone populations diminished to 65% and 80%, or to 20 and 35% at 1 or 6 months, respectively. In conclusion, LP induces in the GCL selective RGCs loss that does not progress after 1 month, and S- and L-cone loss that progresses for up to 6 months. Thus, OHT results in severe damage to both the innermost and the ORL.
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Affiliation(s)
- Arturo Ortín-Martínez
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), 30100 Murcia, Spain
| | - Manuel Salinas-Navarro
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), 30100 Murcia, Spain
| | - Francisco Manuel Nadal-Nicolás
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), 30100 Murcia, Spain
| | - Manuel Jiménez-López
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), 30100 Murcia, Spain
| | - Francisco Javier Valiente-Soriano
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), 30100 Murcia, Spain
| | - Diego García-Ayuso
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), 30100 Murcia, Spain
| | - José Manuel Bernal-Garro
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), 30100 Murcia, Spain
| | - Marcelino Avilés-Trigueros
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), 30100 Murcia, Spain
| | - Marta Agudo-Barriuso
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), 30100 Murcia, Spain
| | - María Paz Villegas-Pérez
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), 30100 Murcia, Spain
| | - Manuel Vidal-Sanz
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), 30100 Murcia, Spain.
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Danias J, Serle J. Can Visual Field Progression be Predicted by Confocal Scanning Laser Ophthalmoscopic Imaging of the Optic Nerve Head in Glaucoma? (An American Ophthalmological Society Thesis). TRANSACTIONS OF THE AMERICAN OPHTHALMOLOGICAL SOCIETY 2015; 113:T4. [PMID: 26549913 PMCID: PMC4622448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
PURPOSE To determine whether confocal scanning laser ophthalmoscopic imaging (Heidelberg retinal tomography [HRT]) can predict visual field change in glaucoma. METHODS The study included 561 patients with glaucoma or ocular hypertension whose clinical course was followed at the Mount Sinai Faculty practice. Humphrey visual fields (HVFs) and HRT images were collected on one randomly selected eye per patient. Glaucoma progression was determined by the presence of two sequential statistically significant negative slopes in mean deviation (MD) or visual field index (VFI) at any point during the study period. Trend-based analysis on HRT parameters was used to determine progressive changes and whether these occurred before or after HVF change. Sensitivity and specificity of HRT to predict HVF change were calculated. HVF rate of change was correlated to the rate of change detected by HRT imaging. RESULTS Approximately 17% of patients progressed by either MD or VFI criteria. MD and VFI correlated highly and identified overlapping sets of patients as progressing. HRT global parameters had poor sensitivity (∼42%) and moderate specificity (∼67%) to predict HVF progression. Regional stereometric parameters were more sensitive (69%-78%) but significantly less specific (24%-27%). Sensitivity of global stereometric parameters in detecting HVF change was not significantly affected by the level of visual field damage (P=.3, Fisher exact test). HVF rate of change did not correlate with rate of change of HRT parameters. CONCLUSIONS Trend-based analysis of HRT parameters has poor sensitivity and specificity in predicting HVF change. This may be related specifically to HRT imaging or may reflect the fact that in some patients with glaucoma, functional changes precede structural alterations.
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Affiliation(s)
- John Danias
- Departments of Ophthalmology and Cell Biology, State University of New York (SUNY), Downstate Medical Center, Brooklyn, New York, and the SUNY Eye Institute
| | - Janet Serle
- Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, New York, New York
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Gandolfi SA, Lim J, Sanseau AC, Parra Restrepo JC, Hamacher T. Randomized trial of brinzolamide/brimonidine versus brinzolamide plus brimonidine for open-angle glaucoma or ocular hypertension. Adv Ther 2014; 31:1213-27. [PMID: 25430900 PMCID: PMC4271137 DOI: 10.1007/s12325-014-0168-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Indexed: 10/31/2022]
Abstract
INTRODUCTION Fixed-combination intraocular pressure (IOP)-lowering medications simplify treatment regimens for patients requiring 2 ocular hypotensive agents to maintain sufficiently low IOP. The aim of this study was to evaluate the safety and efficacy of fixed-combination brinzolamide 1%/brimonidine 0.2% (BBFC) versus concomitant administration of brinzolamide 1% plus brimonidine 0.2% (BRINZ + BRIM) in patients with open-angle glaucoma or ocular hypertension. METHODS This was a prospective, phase 3, multicenter, double-masked, 6-month trial. Patients who had insufficient IOP control with monotherapy or who were receiving 2 IOP-lowering medications were randomized 1:1 to receive twice-daily BBFC or BRINZ + BRIM. IOP was assessed at 9 a.m. and 11 a.m. during week 2, week 6, month 3, and month 6 visits. The primary efficacy endpoint was mean diurnal IOP change from baseline to month 3; noninferiority was concluded if the upper limit of the 95% CI of the between-group difference was <1.5 mmHg. Supportive endpoints included mean IOP, IOP change from baseline, and percentage of patients with IOP <18 mmHg. Adverse events were recorded. RESULTS The mean diurnal IOP change from baseline with BBFC (least squares mean ± standard error -8.5 ± 0.16 mmHg) was noninferior to that with BRINZ + BRIM (-8.3 ± 0.16 mmHg; mean difference -0.1 mmHg; 95% CI -0.5 to 0.2 mmHg). The upper limits of the 95% CIs were <1.5 mmHg at all time points. Decreases from baseline >8 mmHg were observed for least squares mean diurnal IOP in both groups as early as week 2 and continued to the end of the study. The results of all other supportive endpoints were similar to the primary efficacy endpoint. The most common ocular adverse drug reactions were hyperemia of the eye (reported as ocular or conjunctival hyperemia), visual disturbances, ocular allergic reactions, and ocular discomfort. Common systemic adverse drug reactions included dysgeusia, oral dryness, and fatigue/drowsiness. CONCLUSION Brinzolamide 1%/brimonidine 0.2% fixed combination was as well tolerated and effective as concomitant therapy with its components. BBFC reduces treatment burden in patients who require multiple IOP-lowering medications.
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Imaging retinal ganglion cells: enabling experimental technology for clinical application. Prog Retin Eye Res 2014; 44:1-14. [PMID: 25448921 DOI: 10.1016/j.preteyeres.2014.10.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 10/04/2014] [Accepted: 10/18/2014] [Indexed: 11/21/2022]
Abstract
Recent advances in clinical ophthalmic imaging have enhanced patient care. However, the ability to differentiate retinal neurons, such as retinal ganglion cells (RGCs), would advance many areas within ophthalmology, including the screening and monitoring of glaucoma and other optic neuropathies. Imaging at the single cell level would take diagnostics to the next level. Experimental methods have provided techniques and insight into imaging RGCs, however no method has yet to be translated to clinical application. This review provides an overview of the importance of non-invasive imaging of RGCs and the clinically relevant capabilities. In addition, we report on experimental data from wild-type mice that received an in vivo intravitreal injection of a neuronal tracer that labelled RGCs, which in turn were monitored for up to 100 days post-injection with confocal scanning laser ophthalmoscopy. We were able to demonstrate efficient and consistent RGC labelling with this delivery method and discuss the issue of cell specificity. This type of experimental work is important in progressing towards clinically applicable methods for monitoring loss of RGCs in glaucoma and other optic neuropathies. We discuss the challenges to translating these findings to clinical application and how this method of tracking RGCs in vivo could provide valuable structural and functional information to clinicians.
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207
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Paulus JD, Link BA. Loss of optineurin in vivo results in elevated cell death and alters axonal trafficking dynamics. PLoS One 2014; 9:e109922. [PMID: 25329564 PMCID: PMC4199637 DOI: 10.1371/journal.pone.0109922] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 09/12/2014] [Indexed: 12/11/2022] Open
Abstract
Mutations in Optineurin have been associated with ALS, glaucoma, and Paget’s disease of bone in humans, but little is known about how these mutations contribute to disease. Most of the cellular consequences of Optineurin loss have come from in vitro studies, and it remains unclear whether these same defects would be seen in vivo. To answer this question, we assessed the cellular consequences of Optineurin loss in zebrafish embryos to determine if they showed the same defects as have been described in the in vitro studies. We found that loss of Optineurin resulted in increased cell death, as well as subtle cell morphology, cell migration and vesicle trafficking defects. However, unlike experiments on cells in culture, we found no indication that the Golgi apparatus was disrupted or that NF-κB target genes were upregulated. Therefore, we conclude that in vivo loss of Optineurin shows some, but not all, of the defects seen in in vitro work.
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Affiliation(s)
- Jeremiah D. Paulus
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI, United States of America
| | - Brian A. Link
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI, United States of America
- * E-mail:
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208
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Nagai N, Kaji H, Onami H, Katsukura Y, Ishikawa Y, Nezhad ZK, Sampei K, Iwata S, Ito S, Nishizawa M, Nakazawa T, Osumi N, Mashima Y, Abe T. A platform for controlled dual-drug delivery to the retina: protective effects against light-induced retinal damage in rats. Adv Healthc Mater 2014; 3:1555-60, 1524. [PMID: 24753450 DOI: 10.1002/adhm.201400114] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Revised: 03/26/2014] [Indexed: 11/12/2022]
Abstract
Controlled transscleral co-delivery of two drugs, edaravone (EDV) and unoprostone (UNO), using a platform that comprises a microfabricated reservoir, controlled-release cover, and drug formulations, which are made of photopolymerized poly(ethyleneglycol) dimethacrylates, shows synergistic retinal neuroprotection against light injury in rats when compared with single-drug-loaded devices. The device would offer a safer therapeutic method than intravitreal injections for retinal disease treatments.
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Affiliation(s)
- Nobuhiro Nagai
- Division of Clinical Cell Therapy, United Centers for Advanced Research and Translational Medicine (ART); Tohoku University Graduate School of Medicine; 2-1 Seiryo-machi Aoba-ku, Sendai 980-8575 Japan
| | - Hirokazu Kaji
- Department of Bioengineering and Robotics; Graduate School of Engineering, Tohoku University; 6-6-01 Aramaki Aoba-ku, Sendai 980-8579 Japan
| | - Hideyuki Onami
- Division of Clinical Cell Therapy, United Centers for Advanced Research and Translational Medicine (ART); Tohoku University Graduate School of Medicine; 2-1 Seiryo-machi Aoba-ku, Sendai 980-8575 Japan
- Department of Ophthalmology; Tohoku University Graduate School of Medicine; 1-1 Seiryo-machi Aoba-ku, Sendai 980-8574 Japan
| | - Yuki Katsukura
- Division of Clinical Cell Therapy, United Centers for Advanced Research and Translational Medicine (ART); Tohoku University Graduate School of Medicine; 2-1 Seiryo-machi Aoba-ku, Sendai 980-8575 Japan
| | - Yumi Ishikawa
- Division of Clinical Cell Therapy, United Centers for Advanced Research and Translational Medicine (ART); Tohoku University Graduate School of Medicine; 2-1 Seiryo-machi Aoba-ku, Sendai 980-8575 Japan
| | - Zhaleh Kashkouli Nezhad
- Division of Clinical Cell Therapy, United Centers for Advanced Research and Translational Medicine (ART); Tohoku University Graduate School of Medicine; 2-1 Seiryo-machi Aoba-ku, Sendai 980-8575 Japan
| | - Kaori Sampei
- Division of Clinical Cell Therapy, United Centers for Advanced Research and Translational Medicine (ART); Tohoku University Graduate School of Medicine; 2-1 Seiryo-machi Aoba-ku, Sendai 980-8575 Japan
| | - Satoru Iwata
- Division of Clinical Cell Therapy, United Centers for Advanced Research and Translational Medicine (ART); Tohoku University Graduate School of Medicine; 2-1 Seiryo-machi Aoba-ku, Sendai 980-8575 Japan
| | - Shuntaro Ito
- Department of Bioengineering and Robotics; Graduate School of Engineering, Tohoku University; 6-6-01 Aramaki Aoba-ku, Sendai 980-8579 Japan
| | - Matsuhiko Nishizawa
- Department of Bioengineering and Robotics; Graduate School of Engineering, Tohoku University; 6-6-01 Aramaki Aoba-ku, Sendai 980-8579 Japan
| | - Toru Nakazawa
- Department of Ophthalmology; Tohoku University Graduate School of Medicine; 1-1 Seiryo-machi Aoba-ku, Sendai 980-8574 Japan
| | - Noriko Osumi
- Division of Developmental Neuroscience; United Centers for Advanced Research and Translational Medicine (ART); Tohoku University Graduate School of Medicine; 2-1 Seiryo-machi Aoba-ku, Sendai 980-8575 Japan
| | - Yukihiko Mashima
- R-tech Ueno Ltd.; 1-1-7, Uchisaiwai-cho Chiyoda-ku, Tokyo 100-0011 Japan
| | - Toshiaki Abe
- Division of Clinical Cell Therapy, United Centers for Advanced Research and Translational Medicine (ART); Tohoku University Graduate School of Medicine; 2-1 Seiryo-machi Aoba-ku, Sendai 980-8575 Japan
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Li HY, Ruan YW, Ren CR, Cui Q, So KF. Mechanisms of secondary degeneration after partial optic nerve transection. Neural Regen Res 2014; 9:565-74. [PMID: 25206855 PMCID: PMC4146235 DOI: 10.4103/1673-5374.130093] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/05/2014] [Indexed: 01/23/2023] Open
Abstract
Secondary degeneration occurs commonly in the central nervous system after traumatic injuries and following acute and chronic diseases, including glaucoma. A constellation of mechanisms have been shown to be associated with secondary degeneration including apoptosis, necrosis, autophagy, oxidative stress, excitotoxicity, derangements in ionic homeostasis and calcium influx. Glial cells, such as microglia, astrocytes and oligodendrocytes, have also been demonstrated to take part in the process of secondary injury. Partial optic nerve transection is a useful model which was established about 13 years ago. The merit of this model compared with other optic nerve injury models used for glaucoma study, including complete optic nerve transection model and optic nerve crush model, is the possibility to separate primary degeneration from secondary degeneration in location. Therefore, it provides a good tool for the study of secondary degeneration. This review will focus on the research progress of the mechanisms of secondary degeneration using partial optic nerve transection model.
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Affiliation(s)
- Hong-Ying Li
- Department of Ophthalmology, the University of Hong Kong, Hong Kong Special Administrative Region, China ; State Key Laboratory of Brain and Cognitive Science, the University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Yi-Wen Ruan
- GHM Institute of CNS Regeneration, Jinan University, Guangzhou, Guangdong Province, China ; Guangdong Key Laboratory of Brain Function and Diseases, Jinan University, Guangzhou, Guangdong Province, China
| | - Chao-Ran Ren
- GHM Institute of CNS Regeneration, Jinan University, Guangzhou, Guangdong Province, China ; Guangdong Key Laboratory of Brain Function and Diseases, Jinan University, Guangzhou, Guangdong Province, China
| | - Qi Cui
- GHM Institute of CNS Regeneration, Jinan University, Guangzhou, Guangdong Province, China ; Guangdong Key Laboratory of Brain Function and Diseases, Jinan University, Guangzhou, Guangdong Province, China
| | - Kwok-Fai So
- Department of Ophthalmology, the University of Hong Kong, Hong Kong Special Administrative Region, China ; GHM Institute of CNS Regeneration, Jinan University, Guangzhou, Guangdong Province, China ; Guangdong Key Laboratory of Brain Function and Diseases, Jinan University, Guangzhou, Guangdong Province, China ; State Key Laboratory of Brain and Cognitive Science, the University of Hong Kong, Hong Kong Special Administrative Region, China
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D'Orazi FD, Suzuki SC, Wong RO. Neuronal remodeling in retinal circuit assembly, disassembly, and reassembly. Trends Neurosci 2014; 37:594-603. [PMID: 25156327 DOI: 10.1016/j.tins.2014.07.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 07/03/2014] [Accepted: 07/27/2014] [Indexed: 10/24/2022]
Abstract
Developing neuronal circuits often undergo a period of refinement to eliminate aberrant synaptic connections. Inappropriate connections can also form among surviving neurons during neuronal degeneration. The laminar organization of the vertebrate retina enables synaptic reorganization to be readily identified. Synaptic rearrangements are shown to help sculpt developing retinal circuits, although the mechanisms involved remain debated. Structural changes in retinal diseases can also lead to functional rewiring. This poses a major challenge to retinal repair because it may be necessary to untangle the miswired connections before reconnecting with proper synaptic partners. Here, we review our current understanding of the mechanisms that underlie circuit remodeling during retinal development, and discuss how alterations in connectivity during damage could impede circuit repair.
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Affiliation(s)
- Florence D D'Orazi
- Department of Biological Structure, University of Washington, 1959 NE Pacific Street, Seattle, WA 98195, USA
| | - Sachihiro C Suzuki
- Department of Biological Structure, University of Washington, 1959 NE Pacific Street, Seattle, WA 98195, USA
| | - Rachel O Wong
- Department of Biological Structure, University of Washington, 1959 NE Pacific Street, Seattle, WA 98195, USA.
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Chong RS, Martin KR. Retinal ganglion cell dendrites and glaucoma: a case of missing the wood for the trees? EXPERT REVIEW OF OPHTHALMOLOGY 2014. [DOI: 10.1586/17469899.2014.917048] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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212
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Beckel JM, Argall AJ, Lim JC, Xia J, Lu W, Coffey EE, Macarak EJ, Shahidullah M, Delamere NA, Zode GS, Sheffield VC, Shestopalov VI, Laties AM, Mitchell CH. Mechanosensitive release of adenosine 5'-triphosphate through pannexin channels and mechanosensitive upregulation of pannexin channels in optic nerve head astrocytes: a mechanism for purinergic involvement in chronic strain. Glia 2014; 62:1486-501. [PMID: 24839011 DOI: 10.1002/glia.22695] [Citation(s) in RCA: 128] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 05/01/2014] [Accepted: 05/02/2014] [Indexed: 12/21/2022]
Abstract
As adenosine 5'-triphosphate (ATP) released from astrocytes can modulate many neural signaling systems, the triggers and pathways for this ATP release are important. Here, the ability of mechanical strain to trigger ATP release through pannexin channels and the effects of sustained strain on pannexin expression were examined in rat optic nerve head astrocytes. Astrocytes released ATP when subjected to 5% of equibiaxial strain or to hypotonic swelling. Although astrocytes expressed mRNA for pannexins 1-3, connexin 43, and VNUT, pharmacological analysis suggested a predominant role for pannexins in mechanosensitive ATP release, with Rho kinase contribution. Astrocytes from panx1(-/-) mice had reduced baseline and stimulated levels of extracellular ATP, confirming the role for pannexins. Swelling astrocytes triggered a regulatory volume decrease that was inhibited by apyrase or probenecid. The swelling-induced rise in calcium was inhibited by P2X7 receptor antagonists A438079 and AZ10606120, in addition to apyrase and carbenoxolone. Extended stretch of astrocytes in vitro upregulated expression of panx1 and panx2 mRNA. A similar upregulation was observed in vivo in optic nerve head tissue from the Tg-MYOC(Y437H) mouse model of chronic glaucoma; genes for panx1, panx2, and panx3 were increased, whereas immunohistochemistry confirmed increased expression of pannexin 1 protein. In summary, astrocytes released ATP in response to mechanical strain, with pannexin 1 the predominant efflux pathway. Sustained strain upregulated pannexins in vitro and in vivo. Together, these findings provide a mechanism by which extracellular ATP remains elevated under chronic mechanical strain, as found in the optic nerve head of patients with glaucoma.
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Affiliation(s)
- Jonathan M Beckel
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Anesthesiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
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Sponsel WE, Groth SL, Satsangi N, Maddess T, Reilly MA. Refined Data Analysis Provides Clinical Evidence for Central Nervous System Control of Chronic Glaucomatous Neurodegeneration. Transl Vis Sci Technol 2014; 3:1. [PMID: 24932429 DOI: 10.1167/tvst.3.3.1] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Accepted: 03/15/2014] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Refined data analysis was performed to assess binocular visual field conservation in patients with bilateral glaucomatous damage to determine whether unilateral visual field loss is random, anatomically symmetric, or nonrandom in relation to the fellow eye. METHODS This was a case-control study of 47 consecutive patients with bilaterally severe glaucoma; each right eye visual field locus was paired with randomly selected coisopteric left eye loci, with 760,000 (10,000 complete sets of 76 loci) such iterations performed per subject. The potential role of anatomic symmetry in bilateral visual field conservation was also assessed by pairing mirror-image loci of the paired fields. The mean values of the random coisopteric and the symmetric mirror pairings were compared with natural point-for-point pairings of the two eyes by paired t-test. RESULTS Mean unilateral thresholds across the entire visual field were 18.9 dB left and 19.9 dB right (average 19.4), 4 dB lower than the better of the naturally paired concomitant loci of 23.4 dB (P < 10-15). A remarkable natural tendency for conservation of the binocular visual field was confirmed, far stronger than explicable by random chance or anatomic symmetry (P < 0.0001), and reaffirmed by subsequent prospective simultaneous binocular visual field retesting of an arbitrary subset (n = 16) of the study population (P < 0.0001). CONCLUSIONS Refined data analysis of paired visual fields confirms the existence of a natural optimization of binocular visual function in severe bilateral glaucoma via interlocking fields that could be created only by central nervous system (CNS) involvement. TRANSLATIONAL RELEVANCE Integrated bilateral visual field analysis should better define actual visual disability and more accurately reflect the functional efficacy of current ocular and future CNS-oriented therapeutic approaches to the treatment of glaucoma. Glaucomatous eyes provide a highly accessible paired-organ study model for developing therapeutics to optimize conservation of function in neurodegenerative disorders.
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Affiliation(s)
- William E Sponsel
- Department of Biomedical Engineering, University of Texas at San Antonio, San Antonio, TX, USA ; Rosenberg School of Optometry, University of the Incarnate Word, San Antonio, TX, USA ; Baptist Medical Center WESMDPA Glaucoma Service, San Antonio, TX, USA ; Australian Research Council Centre of Excellence in Vision Science, Canberra, Australia
| | - Sylvia L Groth
- University of Minnesota Medical School, Minneapolis, MN, USA
| | - Nancy Satsangi
- University of Texas Health Science Center-San Antonio, San Antonio, TX, USA
| | - Ted Maddess
- Australian Research Council Centre of Excellence in Vision Science, Canberra, Australia
| | - Matthew A Reilly
- Department of Biomedical Engineering, University of Texas at San Antonio, San Antonio, TX, USA
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214
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Absence of transient receptor potential vanilloid-1 accelerates stress-induced axonopathy in the optic projection. J Neurosci 2014; 34:3161-70. [PMID: 24573275 DOI: 10.1523/jneurosci.4089-13.2014] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
How neurons respond to stress in degenerative disease is of fundamental importance for identifying mechanisms of progression and new therapeutic targets. Members of the transient receptor potential (TRP) family of cation-selective ion channels are candidates for mediating stress signals, since different subunits transduce a variety of stimuli relevant in both normal and pathogenic physiology. We addressed this possibility for the TRP vanilloid-1 (TRPV1) subunit by comparing how the optic projection of Trpv1(-/-) mice and age-matched C57 controls responds to stress from elevated ocular pressure, the critical stressor in the most common optic neuropathy, glaucoma. Over a 5 week period of elevated pressure induced by microbead occlusion of ocular fluid, Trpv1(-/-) accelerated both degradation of axonal transport from retinal ganglion cells to the superior colliculus and degeneration of the axons themselves in the optic nerve. Ganglion cell body loss, which is normally later in progression, occurred in nasal sectors of Trpv1(-/-) but not C57 retina. Pharmacological antagonism of TRPV1 in rats similarly accelerated ganglion cell axonopathy. Elevated ocular pressure resulted in differences in spontaneous firing rate and action potential threshold current in Trpv1(-/-) ganglion cells compared with C57. In the absence of elevated pressure, ganglion cells in the two strains had similar firing patterns. Based on these data, we propose that TRPV1 may help neurons respond to disease-relevant stressors by enhancing activity necessary for axonal signaling.
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215
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Yasuda M, Tanaka Y, Ryu M, Tsuda S, Nakazawa T. RNA sequence reveals mouse retinal transcriptome changes early after axonal injury. PLoS One 2014; 9:e93258. [PMID: 24676137 PMCID: PMC3968129 DOI: 10.1371/journal.pone.0093258] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2013] [Accepted: 03/04/2014] [Indexed: 12/23/2022] Open
Abstract
Glaucoma is an ocular disease characterized by progressive retinal ganglion cell (RGC) death caused by axonal injury. However, the underlying mechanisms involved in RGC death remain unclear. In this study, we investigated changes in the transcriptome profile following axonal injury in mice (C57BL/6) with RNA sequencing (RNA-seq) technology. The experiment group underwent an optic nerve crush (ONC) procedure to induce axonal injury in the right eye, and the control group underwent a sham procedure. Two days later, we extracted the retinas and performed RNA-seq and a pathway analysis. We identified 177 differentially expressed genes with RNA-seq, notably the endoplasmic reticulum (ER) stress-related genes Atf3, Atf4, Atf5, Chac1, Chop, Egr1 and Trb3, which were significantly upregulated. The pathway analysis revealed that ATF4 was the most significant upstream regulator. The antioxidative response-related genes Hmox1 and Srxn1, as well as the immune response-related genes C1qa, C1qb and C1qc, were also significantly upregulated. To our knowledge, this is the first reported RNA-seq investigation of the retinal transcriptome and molecular pathways in the early stages after axonal injury. Our results indicated that ER stress plays a key role under these conditions. Furthermore, the antioxidative defense and immune responses occurred concurrently in the early stages after axonal injury. We believe that our study will lead to a better understanding of and insight into the molecular mechanisms underlying RGC death after axonal injury.
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Affiliation(s)
- Masayuki Yasuda
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Yuji Tanaka
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Morin Ryu
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Satoru Tsuda
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Toru Nakazawa
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Japan
- * E-mail:
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216
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Nagai N, Kaji H, Onami H, Ishikawa Y, Nishizawa M, Osumi N, Nakazawa T, Abe T. A polymeric device for controlled transscleral multi-drug delivery to the posterior segment of the eye. Acta Biomater 2014; 10:680-7. [PMID: 24239899 DOI: 10.1016/j.actbio.2013.11.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Revised: 10/26/2013] [Accepted: 11/08/2013] [Indexed: 01/02/2023]
Abstract
The design of drug delivery systems that can deliver multiple drugs to the posterior segment of the eye is a challenging task in retinal disease treatments. We report a polymeric device for multi-drug transscleral delivery at independently controlled release rates. The device comprises a microfabricated reservoir, controlled-release cover and three different fluorescent formulations, which were made of photopolymeized tri(ethyleneglycol)dimethacrylate (TEGDM) and poly(ethyleneglycol)dimethacrylate (PEGDM). The release rate of each fluorescent is controlled by varying the PEGDM/TEGDM ratio in its formulation and the cover. The release kinetics appeared to be related to the swelling ratio of the PEGDM/TEGDM polymers. When the devices were implanted onto rat sclerae, fluorescence was observable in the ocular tissues during 4 weeks' implantation and distributed locally around the implantation site. Our polymeric system, which can administer multiple compounds with distinct kinetics, provides prolonged action and less invasive transscleral administration, and is expected to provide new tools for the treatment of posterior eye diseases with new therapeutic modalities.
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Affiliation(s)
- Nobuhiro Nagai
- Division of Clinical Cell Therapy, United Centers for Advanced Research and Translational Medicine (ART), Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Hirokazu Kaji
- Department of Bioengineering and Robotics, Graduate School of Engineering, Tohoku University, 6-6-01 Aramaki, Aoba-ku, Sendai 980-8579, Japan
| | - Hideyuki Onami
- Division of Clinical Cell Therapy, United Centers for Advanced Research and Translational Medicine (ART), Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan; Department of Ophthalmology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan
| | - Yumi Ishikawa
- Division of Clinical Cell Therapy, United Centers for Advanced Research and Translational Medicine (ART), Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Matsuhiko Nishizawa
- Department of Bioengineering and Robotics, Graduate School of Engineering, Tohoku University, 6-6-01 Aramaki, Aoba-ku, Sendai 980-8579, Japan
| | - Noriko Osumi
- Division of Developmental Neuroscience, United Centers for Advanced Research and Translational Medicine (ART), Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Toru Nakazawa
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan
| | - Toshiaki Abe
- Division of Clinical Cell Therapy, United Centers for Advanced Research and Translational Medicine (ART), Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan.
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217
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Formichella CR, Abella SK, Sims SM, Cathcart HM, Sappington RM. Astrocyte Reactivity: A Biomarker for Retinal Ganglion Cell Health in Retinal Neurodegeneration. ACTA ACUST UNITED AC 2014; 5. [PMID: 25133067 PMCID: PMC4131747 DOI: 10.4172/2155-9899.1000188] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Retinal ganglion cell (RGC) loss in glaucoma is sectorial in nature and preceded by deficits in axonal transport. Neuroinflammation plays an important role in the pathophysiology of glaucoma in the retina, optic nerve and visual centers of the brain, where it similarly appears to be regulated spatially. In a murine model, we examined the spatial characteristics of astrocyte reactivity (migration/proliferation, hypertrophy and GFAP expression) in healthy retina, retina with two glaucoma-related risk factors (aging and genetic predisposition) and glaucomatous retina and established relationships between these reactivity indices and the spatial organization of astrocytes as well as RGC health. Astrocyte reactivity was quantified by morphological techniques and RGC health was determined by uptake and transport of the neural tracer cholera toxin beta subunit (CTB). We found that: (1) astrocyte reactivity occurs in microdomains throughout glaucomatous retina as well as retina with risk factors for glaucoma, (2) these astrocyte microdomains are primarily differentiated by the degree of retinal area covered by the astrocytes within them and (3) percent retinal area covered by astrocytes is highly predictive of RGC health. Our findings suggest that microdomains of astrocyte reactivity are biomarkers for functional decline of RGCs. Based on current and emerging imaging technologies, diagnostic assessment of astrocytes in the nerve fiber layer could succeed in translating axonal transport deficits to a feasible clinical application.
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Affiliation(s)
- Cathryn R Formichella
- Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Simone K Abella
- Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Stephanie M Sims
- Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Heather M Cathcart
- Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Rebecca M Sappington
- Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, Nashville, Tennessee, USA ; Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
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218
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Differential progression of structural and functional alterations in distinct retinal ganglion cell types in a mouse model of glaucoma. J Neurosci 2013; 33:17444-57. [PMID: 24174678 DOI: 10.1523/jneurosci.5461-12.2013] [Citation(s) in RCA: 199] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Intraocular pressure (IOP) elevation is a principal risk factor for glaucoma. Using a microbead injection technique to chronically raise IOP for 15 or 30 d in mice, we identified the early changes in visual response properties of different types of retinal ganglion cells (RGCs) and correlated these changes with neuronal morphology before cell death. Microbead-injected eyes showed reduced optokinetic tracking as well as cell death. In such eyes, multielectrode array recordings revealed that four RGC types show diverse alterations in their light responses upon IOP elevation. OFF-transient RGCs exhibited a more rapid decline in both structural and functional organizations compared with other RGCs. In contrast, although the light-evoked responses of OFF-sustained RGCs were perturbed, the dendritic arbor of this cell type remained intact. ON-transient and ON-sustained RGCs had normal functional receptive field sizes but their spontaneous and light-evoked firing rates were reduced. ON- and OFF-sustained RGCs lost excitatory synapses across an otherwise structurally normal dendritic arbor. Together, our observations indicate that there are changes in spontaneous activity and light-evoked responses in RGCs before detectable dendritic loss. However, when dendrites retract, we found corresponding changes in receptive field center size. Importantly, the effects of IOP elevation are not uniformly manifested in the structure and function of diverse RGC populations, nor are distinct RGC types perturbed within the same time-frame by such a challenge.
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219
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Calkins DJ. Age-related changes in the visual pathways: blame it on the axon. Invest Ophthalmol Vis Sci 2013; 54:ORSF37-41. [PMID: 24335066 DOI: 10.1167/iovs.13-12784] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The aging visual system is marked by a decline in some, but not all, key functions. Some of this decline is attributed to changes in the optics of the eye, but other aspects must have a neural basis. Across mammals, with aging there is remarkable persistence of central structures to which retinal ganglion cell (RGC) axons project with little or no loss of neurons. Similarly, RGC bodies in the retina are subject to variable age-related loss, with most mammals showing none over time. In contrast, the RGC axon itself is highly vulnerable. Across species, the rate of axon loss in the optic nerve is related inversely to the total number of axons at maturity and lifespan. The result of this scaling is approximately a 40% total decline in axon number. Evidence suggests that the consistent vulnerability of RGC axons to aging arises from their high metabolic demand combined with diminishing resources. Thus, therapeutic interventions that conserve bioenergetics may have potential to abate age-related decline in visual function.
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Affiliation(s)
- David J Calkins
- The Vanderbilt Eye Institute and Vanderbilt Brain Institute, Vanderbilt University Medical Center, Nashville, Tennessee
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220
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Guerra Y, Aljohani AJ, Edwards G, Bhattacharya SK. A comparison of trabecular meshwork sphingolipids and ceramides of ocular normotensive and hypertensive states of DBA/2J mice. J Ocul Pharmacol Ther 2013; 30:283-90. [PMID: 24320088 DOI: 10.1089/jop.2013.0168] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
PURPOSE To determine the differential profiles of sphingomyelin, sphingoid base, sphingoid base-1-phosphate, and ceramide and their quantitative differences between trabecular meshwork (TM) derived from normotensive and hypertensive intraocular pressure states of DBA/2J mice. METHODS Normotensive and hypertensive state TM were collected from mice and analyzed. Lipid extraction was performed using the Bligh and Dyer method, and the protein concentrations were determined using the Bradford method. The lipids were identified and quantified using appropriate standards with a TSQ Quantum Access Max triple quadrupole mass spectrometer applying class-specific lipid identification settings. RESULTS The comparative profiles of sphingomyelin, sphingoid base, sphingoid base-1-phosphate, and ceramide between normotensive and hypertensive TM showed several species unique to a phase and as well common between states. CONCLUSION The presence or absence of several sphingolipids and ceramides in the normotensive or hypertensive states may contribute to better understanding of the glaucomas.
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Affiliation(s)
- Yenifer Guerra
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine , Miami, Florida
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221
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Pumphrey SA, Pizzirani S, Pirie CG, Anwer MS, Logvinenko T. Western blot patterns of serum autoantibodies against optic nerve antigens in dogs with goniodysgenesis-related glaucoma. Am J Vet Res 2013; 74:621-8. [PMID: 23531071 DOI: 10.2460/ajvr.74.4.621] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
OBJECTIVE To investigate whether differences existed between clinically normal dogs and dogs with goniodysgenesis-related glaucoma (GDRG) in serum autoantibodies against optic nerve antigens. ANIMALS 16 dogs with GDRG, 17 healthy dogs with unremarkable pectinate ligament and iridocorneal angle morphology, and 13 euthanized dogs with no major ocular abnormalities or underlying diseases. PROCEDURES Western blotting was performed with optic nerve extracts from the euthanized dogs as an antigen source and serum from clinically normal dogs and dogs with GDRG as a primary antibody (autoantibody) source. Blots were evaluated for presence and density of bands. RESULTS Multiple bands were identified on western blots from all dogs with GDRG and all clinically normal dogs, with a high degree of variability among individual dogs. Dogs with GDRG were significantly more likely than healthy dogs to have bands present at 38, 40, and 68 kDa. Dogs with GDRG had significant increases in autoreactivity at 40 and 53 kDa and a significant decrease in autoreactivity at 48 kDa. CONCLUSIONS AND CLINICAL RELEVANCE Significant differences in serum autoantibodies against optic nerve antigens were found in dogs with versus without GDRG. Although it remains unclear whether these differences were part of the pathogenesis of disease or were sequelae to glaucomatous changes, these findings provide support for the hypothesis that immune-mediated mechanisms play a role in the development or progression of GDRG. However, the high degree of variability among individual dogs and the considerable overlap between groups suggest that the clinical usefulness of this technique for distinguishing dogs with GDRG from clinically normal dogs is likely limited.
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Affiliation(s)
- Stephanie A Pumphrey
- Department of Clinical Sciences, Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA 01536, USA
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222
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Ho JK, Stanford MP, Shariati MA, Dalal R, Liao YJ. Optical coherence tomography study of experimental anterior ischemic optic neuropathy and histologic confirmation. Invest Ophthalmol Vis Sci 2013; 54:5981-8. [PMID: 23887804 DOI: 10.1167/iovs.13-12419] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
PURPOSE The optic nerve is part of the central nervous system, and interruption of this pathway due to ischemia typically results in optic atrophy and loss of retinal ganglion cells. In this study, we assessed in vivo retinal changes following murine anterior ischemic optic neuropathy (AION) by using spectral-domain optical coherence tomography (SD-OCT) and compared these anatomic measurements to that of histology. METHODS We induced ischemia at the optic disc via laser-activated photochemical thrombosis, performed serial SD-OCT and manual segmentation of the retinal layers to measure the ganglion cell complex (GCC) and total retinal thickness, and correlated these measurements with that of histology. RESULTS There was impaired perfusion and leakage at the optic disc on fluorescein angiography immediately after AION and severe swelling and distortion of the peripapillary retina on day-1. We used SD-OCT to quantify the changes in retinal thickness following experimental AION, which revealed significant thickening of the GCC on day-1 after ischemia followed by gradual thinning that plateaued by week-3. Thickness of the peripapillary sensory retina was also increased on day-1 and thinned chronically. This pattern of acute retinal swelling and chronic thinning on SD-OCT correlated well with changes seen in histology and corresponded to loss of retinal ganglion layer cells after ischemia. CONCLUSIONS This was a serial SD-OCT quantification of acute and chronic changes following experimental AION, which revealed changes in the GCC similar to that of human AION, but over a time frame of weeks rather than months.
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Affiliation(s)
- Joyce K Ho
- Department of Ophthalmology, Stanford University School of Medicine, Stanford, California, USA
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223
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Payne AJ, Kaja S, Sabates NR, Koulen P. A case for neuroprotection in ophthalmology: developments in translational research. MISSOURI MEDICINE 2013; 110:429-436. [PMID: 24279196 PMCID: PMC3973483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Cellular aging occurs by the lifelong accumulation of oxidative damage leading to neuronal apoptosis, termed 'neurodegeneration', and the functional deficits of aging. Loss of visual function is one of the most important quality of life measures for older adults. We discuss recent clinical and laboratory advances in the neuroprotective treatment of the aging eye with particular emphasis on the three major ocular neurodegenerative conditions: glaucoma, age-related macular degeneration (AMD), and diabetic retinopathy (DR).
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Affiliation(s)
- Andrew J Payne
- Department of Ophthalmology, University of Missouri, Kansas City School of Medicine, USA
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224
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del Olmo-Aguado S, Núñez-Álvarez C, Ji D, Manso AG, Osborne NN. RTP801 immunoreactivity in retinal ganglion cells and its down-regulation in cultured cells protect them from light and cobalt chloride. Brain Res Bull 2013; 98:132-44. [PMID: 23978538 DOI: 10.1016/j.brainresbull.2013.08.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 08/13/2013] [Accepted: 08/14/2013] [Indexed: 10/26/2022]
Abstract
RTP801, a stress-related protein, is activated by adverse environmental conditions and inhibits the activity of mammalian target of rapamycin (mTOR) in promoting oxidative stress-dependent cell death. RTP801 exists both in the mammalian retina and the lens of the eye. Here, we observed RTP801 immunoreactivity in some retinal ganglion cells. Intravitreal injection of cobalt chloride (CoCl2) to mimick hypoxia influenced retinal GFAP (glial fibrillary acidic protein) and heme oxygenase-1 (HO-1) levels, but did not affect RTP801 immunoreactivity or mRNA content relative to GAPDH. However, RTP801 mRNA was elevated when compared with Brn3a mRNA, suggesting that RTP801 is activated in stressed Brn3a retinal ganglion cells. In cultures of RGC-5 cells, RTP801 immunoreactivity was located in the cytoplasm and partly present in the mitochondria. An insult of blue light or CoCl2 increased RTP801 expression, which was accompanied by cell death. However, in cultures where RTP801 mRNA was down-regulated, the negative influence of blue light and CoCl2 was blunted. Rapamycin nullified the CoCl2-induced up-regulation of RTP801 and attenuated cell death. Moreover, rapamycin was non-toxic to RGC-5 cells, even at a high concentration (10μM). The protective effect of rapamycin on RGC-5 cells caused by the inhibition of RTP801 suggests that rapamycin might attenuate retinal ganglion cell death in situ, as in glaucoma.
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Affiliation(s)
- Susana del Olmo-Aguado
- Fundación de Investigación Oftalmológica, Avda. Doctores Fernández-Vega 34, E-33012 Oviedo, Asturias, Spain
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225
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Lindsey JD, Duong-Polk KX, Dai Y, Nguyen DH, Leung CK, Weinreb RN. Protection by an oral disubstituted hydroxylamine derivative against loss of retinal ganglion cell differentiation following optic nerve crush. PLoS One 2013; 8:e65966. [PMID: 23940507 PMCID: PMC3734221 DOI: 10.1371/journal.pone.0065966] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 05/01/2013] [Indexed: 11/19/2022] Open
Abstract
Thy-1 is a cell surface protein that is expressed during the differentiation of retinal ganglion cells (RGCs). Optic nerve injury induces progressive loss in the number of RGCs expressing Thy-1. The rate of this loss is fastest during the first week after optic nerve injury and slower in subsequent weeks. This study was undertaken to determine whether oral treatment with a water-soluble N-hydroxy-2,2,6,6-tetramethylpiperidine derivative (OT-440) protects against loss of Thy-1 promoter activation following optic nerve crush and whether this effect targets the earlier quick phase or the later slow phase. The retina of mice expressing cyan fluorescent protein under control of the Thy-1 promoter (Thy1-CFP mice) was imaged using a blue-light confocal scanning laser ophthalmoscope (bCSLO). These mice then received oral OT-440 prepared in cream cheese or dissolved in water, or plain vehicle, for two weeks and were imaged again prior to unilateral optic nerve crush. Treatments and weekly imaging continued for four more weeks. Fluorescent neurons were counted in the same defined retinal areas imaged at each time point in a masked fashion. When the counts at each time point were directly compared, the numbers of fluorescent cells at each time point were greater in the animals that received OT-440 in cream cheese by 8%, 27%, 52% and 60% than in corresponding control animals at 1, 2, 3 and 4 weeks after optic nerve crush. Similar results were obtained when the vehicle was water. Rate analysis indicated the protective effect of OT-440 was greatest during the first two weeks and was maintained in the second two weeks after crush for both the cream cheese vehicle study and water vehicle study. Because most of the fluorescent cells detected by bCSLO are RGCs, these findings suggest that oral OT-440 can either protect against or delay early degenerative responses occurring in RGCs following optic nerve injury.
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Affiliation(s)
- James D Lindsey
- Hamilton Glaucoma Center and Department of Ophthalmology, University of California San Diego, La Jolla, California, USA.
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226
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Retinal ganglion cells: Energetics, compartmentation, axonal transport, cytoskeletons and vulnerability. Prog Retin Eye Res 2013; 36:217-46. [PMID: 23891817 DOI: 10.1016/j.preteyeres.2013.07.001] [Citation(s) in RCA: 149] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 07/02/2013] [Accepted: 07/02/2013] [Indexed: 11/20/2022]
Abstract
Retinal ganglion cells (RGCs) are specialized projection neurons that relay an immense amount of visual information from the retina to the brain. RGC signal inputs are collected by dendrites and output is distributed from the cell body via very thin (0.5-1 μm) and long (∼50 mm) axons. The RGC cell body is larger than other retinal neurons, but is still only a very small fraction (one ten thousandths) of the length and total surface area of the axon. The total distance traversed by RGCs extends from the retina, starting from synapses with bipolar and amacrine cells, to the brain, to synapses with neurons in the lateral geniculate nucleus. This review will focus on the energy demands of RGCs and the relevant tissues that surround them. RGC survival and function unexceptionally depends upon free energy, predominantly adenosine triphosphate (ATP). RGC energy metabolism is vastly different when compared to that of the photoreceptors. Each subcellular component of the RGC is remarkably different in terms of structure, function and extracellular environment. The energy demands and distribution of each component are also distinct as evidenced by the uneven distribution of mitochondria and ATP within the RGC - signifying the presence of intracellular energy gradients. In this review we will describe RGCs as having four subcellular components, (1) Dendrites, (2) Cell body, (3) Non-myelinated axon, including intraocular and optic nerve head portions, and (4) Myelinated axon, including the intra-orbital and intracranial portions. We will also describe how RGCs integrate information from each subcellular component in order achieve intracellular homeostatic stability as well as respond to perturbations in the extracellular environment. The possible cellular mechanisms such as axonal transport and axonal cytoskeleton proteins that are involved in maintaining RGC energy homeostasis during normal and disease conditions will also be discussed in depth. The emphasis of this review will be on energetic mechanisms within RGC components that have the most relevance to clinical ophthalmology.
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Dapper JD, Crish SD, Pang IH, Calkins DJ. Proximal inhibition of p38 MAPK stress signaling prevents distal axonopathy. Neurobiol Dis 2013; 59:26-37. [PMID: 23859799 DOI: 10.1016/j.nbd.2013.07.001] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 07/04/2013] [Indexed: 12/21/2022] Open
Abstract
The p38 mitogen-activated protein kinase (MAPK) isoforms are phosphorylated by a variety of stress stimuli in neurodegenerative disease and act as upstream activators of myriad pathogenic processes. Thus, p38 MAPK inhibitors are of growing interest as possible therapeutic interventions. Axonal dysfunction is an early component of most neurodegenerative disorders, including the most prevalent optic neuropathy, glaucoma. Sensitivity to intraocular pressure at an early stage disrupts anterograde transport along retinal ganglion cell (RGC) axons to projection targets in the brain with subsequent degeneration of the axons themselves; RGC body loss is much later. Here we show that elevated ocular pressure in rats increases p38 MAPK activation in retina, especially in RGC bodies. Topical eye-drop application of a potent and selective inhibitor of the p38 MAPK catalytic domain (Ro3206145) prevented both the degradation of anterograde transport to the brain and degeneration of axons in the optic nerve. Ro3206145 reduced in the retina phosphorylation of tau and heat-shock protein 27, both down-stream targets of p38 MAPK activation implicated in glaucoma, as well as expression of two inflammatory responses. We also observed increased p38 MAPK activation in mouse models. Thus, inhibition of p38 MAPK signaling in the retina may represent a therapeutic target for preventing early pathogenesis in optic neuropathies.
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Affiliation(s)
- Jason D Dapper
- The Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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228
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Jafarzadehpour E, Radinmehr F, Pakravan M, Mirzajani A, Yazdani S. Pattern electroretinography in glaucoma suspects and early primary open angle glaucoma. J Ophthalmic Vis Res 2013; 8:199-206. [PMID: 24349662 PMCID: PMC3853779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Accepted: 03/16/2013] [Indexed: 11/17/2022] Open
Abstract
PURPOSE To explore retinal ganglion cell (RGC) dysfunction in glaucoma suspects and patients with early primary open angle glaucoma (POAG) using pattern electroretinography (PERG). METHODS Twenty glaucoma suspects (glaucomatous optic disc appearance), 15 early POAG (based on abnormal discs and abnormal visual fields) and 16 normal controls were enrolled. Transient PERG was recorded in response to 0.8° and 16° black and white checkerboard stimuli. Amplitude and peak time (latency) of the P50 and N95 components of the PERG response, and the ratio of N95 amplitude in response to 0.8° and 16° checks were measured. RESULTS N95 peak time (latency) was significantly increased in both early manifest POAG and glaucoma suspects as compared to normal controls (P<0.001). In early POAG, N95 amplitude in response to small (0.8°) checks and the small/large check ratio were reduced in comparison to normal eyes (P<0.05). However, in glaucoma suspects no significant N95 amplitude reduction was observed. No significant difference was observed among the study groups in terms of P50 amplitude or peak time. CONCLUSION The N95 PERG response demonstrated uncoupled peak time and amplitude alterations in glaucoma. N95 peak time was significantly increased both in glaucoma suspects and early POAG; N95 amplitude reduction was present only in early POAG. PERG may detect RGC dysfunction (increased latency) before cell death (decreased amplitude) occurs.
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Affiliation(s)
- Ebrahim Jafarzadehpour
- Department of Optometry, Faculty of Rehabilitation, Iran University of Medical Sciences, Tehran, Iran
| | - Fatemeh Radinmehr
- Department of Optometry, Faculty of Rehabilitation, Iran University of Medical Sciences, Tehran, Iran
| | - Mohammad Pakravan
- Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Ali Mirzajani
- Department of Optometry, Faculty of Rehabilitation, Iran University of Medical Sciences, Tehran, Iran
| | - Shahin Yazdani
- Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran,Correspondence to: Shahin Yazdani, MD. Associate Professor of Ophthalmology, Labbafinejad Medical Center, Paidarfard St., Boostan 9 St., Pasdaran, Tehran 16666, Iran; Tel: +98 21 2258 5952, Fax: +98 21 2259 0607; e-mail:
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229
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Dai Y, Lindsey JD, Duong-Polk KX, Chindasub P, Leung CKS, Weinreb RN. Brimonidine protects against loss of Thy-1 promoter activation following optic nerve crush. BMC Ophthalmol 2013; 13:26. [PMID: 23805828 PMCID: PMC3697983 DOI: 10.1186/1471-2415-13-26] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Accepted: 06/07/2013] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND The loss of RGCs expressing Thy-1 after optic nerve injury has an initial phase of rapid decline followed by a longer phase with slower reduction rate. This study used longitudinal retinal imaging of mice expressing cyan fluorescent protein under control of the Thy-1 promoter (Thy1-CFP mice) to determine how the α2-adrenergic agonist brimonidine influences loss of Thy1 promoter activation. METHODS Baseline images of the fluorescent retinal neurons in 30 Thy1-CFP mice were obtained using a modified confocal scanning laser ophthalmoscope. Next, brimonidine (100 ug/kg, IP) was administered either one time immediately after optic nerve crush, or immediately after optic nerve crush and then every 2 days for four weeks. A control group received a single saline injection immediately after optic nerve crush. All animals were imaged weekly for four weeks after optic nerve crush. Loss of fluorescent retinal neurons within specific retinal areas was determined by counting. RESULTS At one week after optic nerve crush, the proportion of fluorescent retinal neurons retaining fluorescence was 44±7% of baseline in control mice, 51±6% after one brimonidine treatment, and 55±6% after brimonidine treatment every other day (P<0.05 for both brimonidine treatment groups compared to the control group). Subsequently, the number of fluorescent retinal neurons in the group that received one treatment differed insignificantly from the control group. In contrast, the number of fluorescent retinal neurons in the group that received repeated brimonidine treatments was greater than the control group by 28% at two weeks after crush and by 32% at three weeks after crush (P<0.05 at both time points). Rate analysis showed that brimonidine slowed the initial rate of fluorescent cell decline in the animals that received multiple treatments (P<0.05). Differences in the rate of loss among the treatment groups were insignificant after the second week. CONCLUSION Repeated brimonidine treatments protect against loss of fluorescence within fluorescent retinal neurons of Thy1-CFP mice after optic nerve crush. As most of fluorescent retinal neurons in this system are RGCs, these findings indicate that repeated brimonidine treatments may protect RGC health following optic nerve crush.
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Affiliation(s)
- Yi Dai
- Hamilton Glaucoma Center and Department of Ophthalmology, University of California San Diego, La Jolla, CA 92093, USA
- Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China
| | - James D Lindsey
- Hamilton Glaucoma Center and Department of Ophthalmology, University of California San Diego, La Jolla, CA 92093, USA
| | - Karen X Duong-Polk
- Hamilton Glaucoma Center and Department of Ophthalmology, University of California San Diego, La Jolla, CA 92093, USA
| | - Panida Chindasub
- Hamilton Glaucoma Center and Department of Ophthalmology, University of California San Diego, La Jolla, CA 92093, USA
| | | | - Robert N Weinreb
- Hamilton Glaucoma Center and Department of Ophthalmology, University of California San Diego, La Jolla, CA 92093, USA
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230
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Crish SD, Dapper JD, MacNamee SE, Balaram P, Sidorova TN, Lambert WS, Calkins DJ. Failure of axonal transport induces a spatially coincident increase in astrocyte BDNF prior to synapse loss in a central target. Neuroscience 2012; 229:55-70. [PMID: 23159315 DOI: 10.1016/j.neuroscience.2012.10.069] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 10/04/2012] [Accepted: 10/24/2012] [Indexed: 01/07/2023]
Abstract
Failure of anterograde transport to distal targets in the brain is a common feature of neurodegenerative diseases. We have demonstrated in rodent models of glaucoma, the most common optic neuropathy, early loss of anterograde transport along the retinal ganglion cell (RGC) projection to the superior colliculus (SC) is retinotopic and followed by a period of persistence of RGC axon terminals and synapses through unknown molecular pathways. Here we use the DBA/2J mouse model of hereditary glaucoma and an acute rat model to demonstrate that retinotopically focal transport deficits in the SC are accompanied by a spatially coincident increase in brain-derived neurotrophic factor (BDNF), especially in hypertrophic astrocytes. These neurochemical changes occur prior to loss of RGC synapses in the DBA/2J SC. In contrast to BDNF protein, levels of Bdnf mRNA decreased with transport failure, even as mRNA encoding synaptic structures remained unchanged. In situ hybridization signal for Bdnf mRNA was the strongest in SC neurons, and labeling for the immature precursor pro-BDNF was very limited. Subcellular fractionation of SC indicated that membrane-bound BDNF decreased with age in the DBA/2J, while BDNF released from vesicles remained high. These results suggest that in response to diminished axonal function, activated astrocytes in the brain may sequester mature BDNF released from target neurons to counter stressors that otherwise would challenge survival of projection synapses.
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Affiliation(s)
- S D Crish
- The Vanderbilt Eye Institute, Vanderbilt University Medical Center, 11425 Langford Medical Research Building IV, 2213 Garland Avenue, Nashville, TN 37232, USA.
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231
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Osborne NN, del Olmo-Aguado S. Maintenance of retinal ganglion cell mitochondrial functions as a neuroprotective strategy in glaucoma. Curr Opin Pharmacol 2012; 13:16-22. [PMID: 22999653 DOI: 10.1016/j.coph.2012.09.002] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Revised: 09/03/2012] [Accepted: 09/03/2012] [Indexed: 12/26/2022]
Abstract
Loss of vision in glaucoma occurs because retinal ganglion cells (RGCs) die. RGCs have probably more mitochondria than any other neurone in the CNS. It is proposed that stress to mitochondria of individual RGCs is a major trigger of the disease and also provides an explanation why different RGCs die at different times. Pharmacological agents that can maintain mitochondrial functions, in particular to attenuate oxidative stress and to sustain energy production, might therefore provide a novel way of slowing down RGC death and help in the treatment of glaucoma.
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Affiliation(s)
- Neville N Osborne
- Fundación de Investigación Oftalmológica, Avda. Doctores Fernández-Vega 34, E-33012 Oviedo, Asturias, Spain.
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