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Maciulaitiene R, Kalesnykas G, Pauza DH, Januleviciene I. A combination of topical and systemic administration of brimonidine is neuroprotective in the murine optic nerve crush model. PLoS One 2024; 19:e0308671. [PMID: 39116180 PMCID: PMC11309405 DOI: 10.1371/journal.pone.0308671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Accepted: 07/22/2024] [Indexed: 08/10/2024] Open
Abstract
Glaucoma is a multifactorial optic neuropathy that primarily affecting retinal ganglion cells (RGC). Brimonidine is an intraocular pressure-lowering drug with reported neuroprotective properties. This study aimed to compare the neuroprotective effects of topical and intraperitoneal (IP) brimonidine on RGCs from different retinal segments in a murine optic nerve crush (ONC) model. METHODS forty-one Balb/c mice underwent unilateral ONC and were divided into three study groups: fifteen animals received saline drops twice per day and two additional IP injections of saline; fourteen mice received brimonidine drops twice per day; and 12 mice received brimonidine eye drops twice per day and two additional IP brimonidine injections. Animals were sacrificed seven days post-ONC, and immunohistochemical staining of retinal whole mounts was performed using neuronal NeuN and GFAP staining. Microscopic pictures of the central, middle, and peripheral regions of the retina were taken. The density of the retinal cells was assessed. RESULTS The total RGC density after ONC and RGC densities in all retinal eccentricities were significantly higher in the brimonidine eye drop and IP combination treatment group than in the saline drop + saline IP, and brimonidine drop treatment groups. CONCLUSIONS brimonidine eye drops supplemented with IP brimonidine injections improved RGC survival in a preclinical model of ONC.
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Affiliation(s)
- Ruta Maciulaitiene
- Department of Ophthalmology, Academy of Medicine, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Giedrius Kalesnykas
- Experimentica Ltd., Kuopio, Finland
- Experimentica UAB, Vilnius, Lithuania
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Dainius Haroldas Pauza
- Academy of Medicine, Institute of Anatomy, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Ingrida Januleviciene
- Department of Ophthalmology, Academy of Medicine, Lithuanian University of Health Sciences, Kaunas, Lithuania
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2
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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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3
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Otsubo M, Sase K, Tsukahara C, Fujita N, Arizono I, Tokuda N, Kitaoka Y. Axonal protection by combination of ripasudil and brimonidine with upregulation of p-AMPK in TNF-induced optic nerve degeneration. Int Ophthalmol 2024; 44:173. [PMID: 38598101 PMCID: PMC11006787 DOI: 10.1007/s10792-024-03095-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Accepted: 03/05/2024] [Indexed: 04/11/2024]
Abstract
PURPOSE The ROCK inhibitor ripasudil hydrochloride hydrate was shown to have axonal protective effects in TNF-induced optic nerve degeneration. The α2-adrenoreceptor agonist brimonidine was also shown to exert axonal protection. The current study aimed to elucidate whether additive axonal protection was achieved by the simultaneous injection of ripasudil and brimonidine and examine the association with AMPK activation. METHODS Intravitreal administration was performed in the following groups: PBS, TNF, or TNF with ripasudil, with brimonidine, or with a combination of ripasudil and brimonidine. Axon numbers were counted to evaluate the effects against axon loss. Immunoblot analysis was performed to examine phosphorylated AMPK expression in optic nerves, and immunohistochemical analysis was performed to evaluate the expression levels of p-AMPK and neurofilament in the optic nerve. RESULTS Both ripasudil alone or brimonidine alone resulted in significant neuroprotection against TNF-induced axon loss. The combination of ripasudil and brimonidine showed additive protective effects. Combined ripasudil and brimonidine plus TNF significantly upregulated p-AMPK levels in the optic nerve compared with the TNF groups. Immunohistochemical analysis revealed that p-AMPK is present in axons and enhanced by combination therapy. CONCLUSION The combination of ripasudil and brimonidine may have additive protective effects compared with single-agent treatment alone. These protective effects may be at least partially associated with AMPK activation.
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Affiliation(s)
- Mizuki Otsubo
- Department of Molecular Neuroscience, St. Marianna University Graduate School of Medicine, 2-16-1 Sugao, Miyamae-Ku, Kaswasaki, Kanagawa, 216-8511, Japan.
- Department of Ophthalmology, St. Marianna University School of Medicine, Kaswasaki, Japan.
| | - Kana Sase
- Department of Ophthalmology, St. Marianna University School of Medicine, Kaswasaki, Japan
| | - Chihiro Tsukahara
- Department of Ophthalmology, St. Marianna University School of Medicine, Kaswasaki, Japan
| | - Naoki Fujita
- Department of Ophthalmology, St. Marianna University School of Medicine, Kaswasaki, Japan
| | - Ibuki Arizono
- Department of Molecular Neuroscience, St. Marianna University Graduate School of Medicine, 2-16-1 Sugao, Miyamae-Ku, Kaswasaki, Kanagawa, 216-8511, Japan
- Department of Ophthalmology, St. Marianna University School of Medicine, Kaswasaki, Japan
| | - Naoto Tokuda
- Department of Ophthalmology, St. Marianna University School of Medicine, Kaswasaki, Japan
| | - Yasushi Kitaoka
- Department of Molecular Neuroscience, St. Marianna University Graduate School of Medicine, 2-16-1 Sugao, Miyamae-Ku, Kaswasaki, Kanagawa, 216-8511, Japan
- Department of Ophthalmology, St. Marianna University School of Medicine, Kaswasaki, Japan
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Feng KM, Tsung TH, Chen YH, Lu DW. The Role of Retinal Ganglion Cell Structure and Function in Glaucoma. Cells 2023; 12:2797. [PMID: 38132117 PMCID: PMC10741833 DOI: 10.3390/cells12242797] [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: 10/30/2023] [Revised: 11/29/2023] [Accepted: 11/29/2023] [Indexed: 12/23/2023] Open
Abstract
Glaucoma, a leading cause of irreversible blindness globally, primarily affects retinal ganglion cells (RGCs). This review dives into the anatomy of RGC subtypes, covering the different underlying theoretical mechanisms that lead to RGC susceptibility in glaucoma, including mechanical, vascular, excitotoxicity, and neurotrophic factor deficiency, as well as oxidative stress and inflammation. Furthermore, we examined numerous imaging methods and functional assessments to gain insight into RGC health. Finally, we investigated the current possible neuroprotective targets for RGCs that could help with future glaucoma research and management.
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Affiliation(s)
| | | | | | - Da-Wen Lu
- Department of Ophthalmology, Tri-Service General Hospital, National Defense Medical Center, Taipei 11490, Taiwan; (K.M.F.); (T.-H.T.); (Y.-H.C.)
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Orii Y, Kunikane E, Yamada Y, Morioka M, Iwasaki K, Arimura S, Mizuno A, Inatani M. Ocular Distribution of Brimonidine and Brinzolamide after Topical Instillation of a 0.1% Brimonidine Tartrate and 1% Brinzolamide Fixed-Combination Ophthalmic Suspension: An Interventional Study. J Clin Med 2023; 12:4175. [PMID: 37445209 DOI: 10.3390/jcm12134175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 06/08/2023] [Accepted: 06/16/2023] [Indexed: 07/15/2023] Open
Abstract
PURPOSE To evaluate the concentrations of brimonidine and brinzolamide in the vitreous and aqueous humor after instillation of a 0.1% brimonidine tartrate and 1% brinzolamide fixed-combination ophthalmic suspension. METHODS The present investigation involved patients with macular holes or idiopathic epiretinal membranes who were planning to undergo vitrectomy. One week prior to surgery, the patients received twice-daily topical treatment with 0.1% brimonidine tartrate and 1% brinzolamide fixed-combination ophthalmic suspension. Before vitrectomy, vitreous and aqueous humor samples were collected, and the mean concentrations of brimonidine and brinzolamide were determined through liquid chromatography-tandem spectrometry. RESULTS Ten eyes (nine phakic and one pseudophakic eyes; 10 patients) were examined. The concentration of brimonidine in vitreous and aqueous humor samples was 5.02 ± 2.24 and 559 ± 670 nM, respectively. The concentration of brimonidine in the vitreous humor, which is needed to activate α2 receptors, was >2 nM in all patients. The concentration of brinzolamide was 8.96 ± 4.65 and 1100 ± 813 nM, respectively. However, there was no significant correlation between the concentrations of brimonidine in the vitreous and aqueous humor samples. CONCLUSIONS Sufficient concentrations of brimonidine were detected in all vitreous samples. The dissociated correlation of the drug concentrations between aqueous and vitreous humors implies the possibility of another pathway to vitreous humor, different from the pathway to aqueous humor.
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Affiliation(s)
- Yusuke Orii
- Department of Ophthalmology, Faculty of Medical Sciences, University of Fukui, Fukui 910-1193, Japan
| | | | - Yutaka Yamada
- Department of Ophthalmology, Faculty of Medical Sciences, University of Fukui, Fukui 910-1193, Japan
| | - Masakazu Morioka
- Department of Ophthalmology, Faculty of Medical Sciences, University of Fukui, Fukui 910-1193, Japan
| | - Kentaro Iwasaki
- Department of Ophthalmology, Faculty of Medical Sciences, University of Fukui, Fukui 910-1193, Japan
| | - Shogo Arimura
- Department of Ophthalmology, Faculty of Medical Sciences, University of Fukui, Fukui 910-1193, Japan
| | - Akemi Mizuno
- Senju Pharmaceutical Co., Ltd., Osaka 541-0048, Japan
| | - Masaru Inatani
- Department of Ophthalmology, Faculty of Medical Sciences, University of Fukui, Fukui 910-1193, Japan
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Garner MA, Strickland RG, Girkin CA, Gross AK. Mechanisms of retinal ganglion cell injury following acute increases in intraocular pressure. FRONTIERS IN OPHTHALMOLOGY 2022; 2:1007103. [PMID: 38983517 PMCID: PMC11182138 DOI: 10.3389/fopht.2022.1007103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 10/26/2022] [Indexed: 07/11/2024]
Abstract
The maintenance of intraocular pressure (IOP) is critical to preserving the pristine optics required for vision. Disturbances in IOP can directly impact the optic nerve and retina, and inner retinal injury can occur following acute and chronic IOP elevation. There are a variety of animal models that have been developed to study the effects of acute and chronic elevation of IOP on the retina, retinal ganglion cell (RGC) morphology, intracellular signaling, gene expression changes, and survival. Acute IOP models induce injury that allows for the study of RGC response to well characterized injury and potential recovery. This review will focus on the initial impact of acute IOP elevation on RGC injury and recovery as these early responses may be the best targets for potential therapeutic interventions to promote RGC survival in glaucoma.
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Affiliation(s)
- Mary Anne Garner
- Department of Neurobiology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Ryan G. Strickland
- Department of Neurobiology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Christopher A. Girkin
- Department of Neurobiology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Alecia K. Gross
- Department of Neurobiology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
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7
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Orii Y, Kunikane E, Yamada Y, Morioka M, Iwasaki K, Arimura S, Mizuno A, Inatani M. Brimonidine and timolol concentrations in the human vitreous and aqueous humors after topical instillation of a 0.1% brimonidine tartrate and 0.5% timolol fixed-combination ophthalmic solution: An interventional study. PLoS One 2022; 17:e0277313. [PMID: 36454807 PMCID: PMC9714730 DOI: 10.1371/journal.pone.0277313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Accepted: 10/22/2022] [Indexed: 12/03/2022] Open
Abstract
PURPOSE To evaluate the concentrations of brimonidine and timolol in the vitreous and aqueous humors after instillation of a 0.1% brimonidine tartrate and 0.5% timolol fixed-combination ophthalmic solution. METHODS This single-arm open-label interventional study included patients with macular holes or idiopathic epiretinal membranes who were scheduled for vitrectomy. Written informed consent was obtained from all participants. A 0.1% brimonidine tartrate and 0.5% timolol fixed-combination ophthalmic solution was administered topically twice daily for 1 week preoperatively. The vitreous and aqueous humors were sampled before vitrectomy, and brimonidine and timolol concentrations were quantified using liquid chromatography-tandem spectrometry. This study was registered with the Japan Registry of Clinical Trials (jRCT, ID jRCTs051200008; date of access and registration: April 28, 2020). The study protocol was approved by the University of Fukui Certified Review Board (CRB) and complied with the tenets of the Declaration of Helsinki. RESULTS Eight eyes of eight patients (7 phakic eyes and 1 pseudophakic eye) were included in this study. The mean brimonidine concentrations in the vitreous and aqueous humors were 5.04 ± 4.08 nM and 324 ± 172 nM, respectively. Five of the eight patients had brimonidine concentrations >2 nM in the vitreous humor, which is necessary to activate α2 receptors. The mean timolol concentrations in the vitreous and aqueous humors were 65.6 ± 56.0 nM and 3,160 ± 1,570 nM, respectively. Brimonidine concentrations showed significant positive correlations with timolol concentrations in the vitreous humor (P < 0.0001, R2 = 0.97) and aqueous humor (P < 0.0001, R2 = 0.96). CONCLUSIONS The majority of patients who received a 0.1% brimonidine tartrate and 0.5% timolol topical fixed-combination ophthalmic solution showed a brimonidine concentration >2 nM in the vitreous humor. Brimonidine and timolol may be distributed in the ocular tissues through an identical pathway after topical instillation.
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Affiliation(s)
- Yusuke Orii
- Department of Ophthalmology, Faculty of Medical Sciences, University of Fukui, Fukui, Japan
| | | | - Yutaka Yamada
- Department of Ophthalmology, Faculty of Medical Sciences, University of Fukui, Fukui, Japan
| | - Masakazu Morioka
- Department of Ophthalmology, Faculty of Medical Sciences, University of Fukui, Fukui, Japan
| | - Kentaro Iwasaki
- Department of Ophthalmology, Faculty of Medical Sciences, University of Fukui, Fukui, Japan
| | - Shogo Arimura
- Department of Ophthalmology, Faculty of Medical Sciences, University of Fukui, Fukui, Japan
| | | | - Masaru Inatani
- Department of Ophthalmology, Faculty of Medical Sciences, University of Fukui, Fukui, Japan
- * E-mail:
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Nam MH, Nahomi RB, Pantcheva MB, Dhillon A, Chiodo VA, Smith WC, Nagaraj RH. AAV2-Mediated Expression of HspB1 in RGCs Prevents Somal Damage and Axonal Transport Deficits in a Mouse Model of Ocular Hypertension. Transl Vis Sci Technol 2022; 11:8. [DOI: 10.1167/tvst.11.11.8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Mi-Hyun Nam
- Sue Anschutz-Rodgers Eye Center and Department of Ophthalmology, School of Medicine, University of Colorado, Anschutz Medical Campus, Aurora, CO, USA
| | - Rooban B. Nahomi
- Sue Anschutz-Rodgers Eye Center and Department of Ophthalmology, School of Medicine, University of Colorado, Anschutz Medical Campus, Aurora, CO, USA
| | - Mina B. Pantcheva
- Sue Anschutz-Rodgers Eye Center and Department of Ophthalmology, School of Medicine, University of Colorado, Anschutz Medical Campus, Aurora, CO, USA
| | - Armaan Dhillon
- Sue Anschutz-Rodgers Eye Center and Department of Ophthalmology, School of Medicine, University of Colorado, Anschutz Medical Campus, Aurora, CO, USA
| | - Vince A. Chiodo
- Department of Ophthalmology, University of Florida, Gainesville, FL, USA
| | - W. Clay Smith
- Department of Ophthalmology, University of Florida, Gainesville, FL, USA
| | - Ram H. Nagaraj
- Sue Anschutz-Rodgers Eye Center and Department of Ophthalmology, School of Medicine, University of Colorado, Anschutz Medical Campus, Aurora, CO, USA
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, Aurora, CO, USA
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Watanabe M, Sato T, Tsugeno Y, Higashide M, Furuhashi M, Umetsu A, Suzuki S, Ida Y, Hikage F, Ohguro H. An α2-Adrenergic Agonist, Brimonidine, Beneficially Affects the TGF-β2-Treated Cellular Properties in an In Vitro Culture Model. Bioengineering (Basel) 2022; 9:bioengineering9070310. [PMID: 35877361 PMCID: PMC9312232 DOI: 10.3390/bioengineering9070310] [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: 06/11/2022] [Revised: 07/06/2022] [Accepted: 07/11/2022] [Indexed: 11/16/2022] Open
Abstract
We report herein on the effects of brimonidine (BRI), an α2-adrenergic agonist, on two-dimensional (2D) and three-dimensional (3D) cell-cultured TGF-β2-untreated and -treated human trabecular meshwork (HTM) cells. In the presence of TGF-β2 (5 ng/mL), (1) the effects of BRI on (1) the 2D HTM monolayers’ barrier function were investigated as estimated using trans-endothelial electrical resistance (TEER) measurement and FITC dextran permeability; (2) real-time analyses of cellular metabolism using a Seahorse Bioanalyzer; (3) the largeness and hardness of 3D spheroids; and (4) the expression of genes that encode extracellular matrix (ECM) proteins, including collagens (COL) 1, 4, and 6; fibronectin (FN) and α-smooth muscle actin (α-SMA); ECM modulators, including a tissue inhibitor of matrix proteinase (TIMP) 1–4; matrix metalloproteinase (MMP) 2, 9, and 14; and several endoplasmic reticulum (ER) stress-related genes, including the X-box-binding protein 1 (XBP1), the spliced XBP1 (sXBP1), glucose-regulated protein (GRP)78, GRP94, and CCAAT-enhancer-binding protein homologous protein (CHOP). BRI markedly inhibited the TGF-β2-induced increase in the values of TEER of the 2D cell monolayer and the hardness of the 3D spheroids, although it had no effect on their sizes. BRI also cancelled the TGF-β2-induced reduction in mitochondrial maximal respiration but had no effect on the glycolytic capacity. In addition, the gene expression of these molecules was quite different between the 2D and 3D cultures of HTM cells. The present observations found in this study indicate that BRI may beneficially affect TGF-β2-induced changes in both cultures, 2D and 3D, of HTM cells, although their structural and functional properties that were altered varied significantly between both cultures of HTM cells.
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Affiliation(s)
- Megumi Watanabe
- Departments of Ophthalmology, School of Medicine, Sapporo Medical University, Sapporo 060-8556, Japan; (M.W.); (Y.T.); (M.H.); (A.U.); (S.S.); (Y.I.); (F.H.)
| | - Tatsuya Sato
- Departments of Cardiovascular, Renal and Metabolic Medicine, Sapporo Medical University, Sapporo 060-8556, Japan; (T.S.); (M.F.)
- Departments of Cellular Physiology and Signal Transduction, Sapporo Medical University, Sapporo 060-8556, Japan
| | - Yuri Tsugeno
- Departments of Ophthalmology, School of Medicine, Sapporo Medical University, Sapporo 060-8556, Japan; (M.W.); (Y.T.); (M.H.); (A.U.); (S.S.); (Y.I.); (F.H.)
| | - Megumi Higashide
- Departments of Ophthalmology, School of Medicine, Sapporo Medical University, Sapporo 060-8556, Japan; (M.W.); (Y.T.); (M.H.); (A.U.); (S.S.); (Y.I.); (F.H.)
| | - Masato Furuhashi
- Departments of Cardiovascular, Renal and Metabolic Medicine, Sapporo Medical University, Sapporo 060-8556, Japan; (T.S.); (M.F.)
| | - Araya Umetsu
- Departments of Ophthalmology, School of Medicine, Sapporo Medical University, Sapporo 060-8556, Japan; (M.W.); (Y.T.); (M.H.); (A.U.); (S.S.); (Y.I.); (F.H.)
| | - Soma Suzuki
- Departments of Ophthalmology, School of Medicine, Sapporo Medical University, Sapporo 060-8556, Japan; (M.W.); (Y.T.); (M.H.); (A.U.); (S.S.); (Y.I.); (F.H.)
| | - Yosuke Ida
- Departments of Ophthalmology, School of Medicine, Sapporo Medical University, Sapporo 060-8556, Japan; (M.W.); (Y.T.); (M.H.); (A.U.); (S.S.); (Y.I.); (F.H.)
| | - Fumihito Hikage
- Departments of Ophthalmology, School of Medicine, Sapporo Medical University, Sapporo 060-8556, Japan; (M.W.); (Y.T.); (M.H.); (A.U.); (S.S.); (Y.I.); (F.H.)
| | - Hiroshi Ohguro
- Departments of Ophthalmology, School of Medicine, Sapporo Medical University, Sapporo 060-8556, Japan; (M.W.); (Y.T.); (M.H.); (A.U.); (S.S.); (Y.I.); (F.H.)
- Correspondence: ; Tel.: +81-611-2111
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10
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Combined drug triads for synergic neuroprotection in retinal degeneration. Biomed Pharmacother 2022; 149:112911. [DOI: 10.1016/j.biopha.2022.112911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 03/28/2022] [Accepted: 03/29/2022] [Indexed: 11/23/2022] Open
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11
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Dias MS, Luo X, Ribas VT, Petrs-Silva H, Koch JC. The Role of Axonal Transport in Glaucoma. Int J Mol Sci 2022; 23:ijms23073935. [PMID: 35409291 PMCID: PMC8999615 DOI: 10.3390/ijms23073935] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 03/28/2022] [Accepted: 03/31/2022] [Indexed: 11/16/2022] Open
Abstract
Glaucoma is a neurodegenerative disease that affects the retinal ganglion cells (RGCs) and leads to progressive vision loss. The first pathological signs can be seen at the optic nerve head (ONH), the structure where RGC axons leave the retina to compose the optic nerve. Besides damage of the axonal cytoskeleton, axonal transport deficits at the ONH have been described as an important feature of glaucoma. Axonal transport is essential for proper neuronal function, including transport of organelles, synaptic components, vesicles, and neurotrophic factors. Impairment of axonal transport has been related to several neurodegenerative conditions. Studies on axonal transport in glaucoma include analysis in different animal models and in humans, and indicate that its failure happens mainly in the ONH and early in disease progression, preceding axonal and somal degeneration. Thus, a better understanding of the role of axonal transport in glaucoma is not only pivotal to decipher disease mechanisms but could also enable early therapies that might prevent irreversible neuronal damage at an early time point. In this review we present the current evidence of axonal transport impairment in glaucomatous neurodegeneration and summarize the methods employed to evaluate transport in this disease.
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Affiliation(s)
- Mariana Santana Dias
- Intermediate Laboratory of Gene Therapy and Viral Vectors, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Rio de Janeiro 21941-902, Brazil; (M.S.D.); (H.P.-S.)
| | - Xiaoyue Luo
- Department of Neurology, University Medical Center Göttingen, 37077 Göttingen, Germany;
| | - Vinicius Toledo Ribas
- Laboratory of Neurobiology, Department of Morphology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte 31270-901, Brazil;
| | - Hilda Petrs-Silva
- Intermediate Laboratory of Gene Therapy and Viral Vectors, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Rio de Janeiro 21941-902, Brazil; (M.S.D.); (H.P.-S.)
| | - Jan Christoph Koch
- Department of Neurology, University Medical Center Göttingen, 37077 Göttingen, Germany;
- Correspondence:
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Ribeiro M, McGrady NR, Baratta RO, Del Buono BJ, Schlumpf E, Calkins DJ. Intraocular Delivery of a Collagen Mimetic Peptide Repairs Retinal Ganglion Cell Axons in Chronic and Acute Injury Models. Int J Mol Sci 2022; 23:ijms23062911. [PMID: 35328332 PMCID: PMC8949359 DOI: 10.3390/ijms23062911] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 03/01/2022] [Accepted: 03/02/2022] [Indexed: 01/05/2023] Open
Abstract
Vision loss through the degeneration of retinal ganglion cell (RGC) axons occurs in both chronic and acute conditions that target the optic nerve. These include glaucoma, in which sensitivity to intraocular pressure (IOP) causes early RGC axonal dysfunction, and optic nerve trauma, which causes rapid axon degeneration from the site of injury. In each case, degeneration is irreversible, necessitating new therapeutics that protect, repair, and regenerate RGC axons. Recently, we demonstrated the reparative capacity of using collagen mimetic peptides (CMPs) to heal fragmented collagen in the neuronal extracellular milieu. This was an important step in the development of neuronal-based therapies since neurodegeneration involves matrix metalloproteinase (MMP)-mediated remodeling of the collagen-rich environment in which neurons and their axons exist. We found that intraocular delivery of a CMP comprising single-strand fractions of triple helix human type I collagen prevented early RGC axon dysfunction in an inducible glaucoma model. Additionally, CMPs also promoted neurite outgrowth from dorsal root ganglia, challenged in vitro by partial digestion of collagen. Here, we compared the ability of a CMP sequence to protect RGC axons in both inducible glaucoma and optic nerve crush. A three-week +40% elevation in IOP caused a 67% degradation in anterograde transport to the superior colliculus, the primary retinal projection target in rodents. We found that a single intravitreal injection of CMP during the period of IOP elevation significantly reduced this degradation. The same CMP delivered shortly after optic nerve crush promoted significant axonal recovery during the two-week period following injury. Together, these findings support a novel protective and reparative role for the use of CMPs in both chronic and acute conditions affecting the survival of RGC axons in the optic projection to the brain.
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Affiliation(s)
- Marcio Ribeiro
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, AA7103 MCN/VUIIS, 1161 21st Ave. S., Nashville, TN 37232, USA; (M.R.); (N.R.M.)
| | - Nolan R. McGrady
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, AA7103 MCN/VUIIS, 1161 21st Ave. S., Nashville, TN 37232, USA; (M.R.); (N.R.M.)
| | - Robert O. Baratta
- Stuart Therapeutics, Inc., 411 SE Osceola St., Suite 203, Stuart, FL 34994, USA; (R.O.B.); (B.J.D.B.); (E.S.)
| | - Brian J. Del Buono
- Stuart Therapeutics, Inc., 411 SE Osceola St., Suite 203, Stuart, FL 34994, USA; (R.O.B.); (B.J.D.B.); (E.S.)
| | - Eric Schlumpf
- Stuart Therapeutics, Inc., 411 SE Osceola St., Suite 203, Stuart, FL 34994, USA; (R.O.B.); (B.J.D.B.); (E.S.)
| | - David J. Calkins
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, AA7103 MCN/VUIIS, 1161 21st Ave. S., Nashville, TN 37232, USA; (M.R.); (N.R.M.)
- Correspondence: ; Tel.: +1-(615)-936-1424; Fax: +1-(615)-936-6410
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Risner ML, Pasini S, McGrady NR, Calkins DJ. Bax Contributes to Retinal Ganglion Cell Dendritic Degeneration During Glaucoma. Mol Neurobiol 2022; 59:1366-1380. [PMID: 34984584 PMCID: PMC8882107 DOI: 10.1007/s12035-021-02675-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 11/30/2021] [Indexed: 12/14/2022]
Abstract
The BCL-2 (B-cell lymphoma-2) family of proteins contributes to mitochondrial-based apoptosis in models of neurodegeneration, including glaucomatous optic neuropathy (glaucoma), which degrades the retinal ganglion cell (RGC) axonal projection to the visual brain. Glaucoma is commonly associated with increased sensitivity to intraocular pressure (IOP) and involves a proximal program that leads to RGC dendritic pruning and a distal program that underlies axonopathy in the optic projection. While genetic deletion of the Bcl2-associated X protein (Bax-/-) prolongs RGC body survival in models of glaucoma and optic nerve trauma, axonopathy persists, thus raising the question of whether dendrites and the RGC light response are protected. Here, we used an inducible model of glaucoma in Bax-/- mice to determine if Bax contributes to RGC dendritic degeneration. We performed whole-cell recordings and dye filling in RGCs signaling light onset (αON-Sustained) and offset (αOFF-Sustained). We recovered RGC dendritic morphologies by confocal microscopy and analyzed dendritic arbor complexity and size. Additionally, we assessed RGC axon function by measuring anterograde axon transport of cholera toxin subunit B to the superior colliculus and behavioral spatial frequency threshold (i.e., spatial acuity). We found 1 month of IOP elevation did not cause significant RGC death in either WT or Bax-/- retinas. However, IOP elevation reduced dendritic arbor complexity of WT αON-Sustained and αOFF-Sustained RGCs. In the absence of Bax, αON- and αOFF-Sustained RGC dendritic arbors remained intact following IOP elevation. In addition to dendrites, neuroprotection by Bax-/- generalized to αON-and αOFF-Sustained RGC light- and current-evoked responses. Both anterograde axon transport and spatial acuity declined during IOP elevation in WT and Bax-/- mice. Collectively, our results indicate Bax contributes to RGC dendritic degeneration and distinguishes the proximal and distal neurodegenerative programs involved during the progression of glaucoma.
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Affiliation(s)
- Michael L Risner
- Vanderbilt Eye Institute, Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, AA7103 MCN/VUIIS, 1161 21st Ave. S., Nashville, TN, 37232, USA
| | - Silvia Pasini
- Vanderbilt Eye Institute, Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, AA7103 MCN/VUIIS, 1161 21st Ave. S., Nashville, TN, 37232, USA
| | - Nolan R McGrady
- Vanderbilt Eye Institute, Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, AA7103 MCN/VUIIS, 1161 21st Ave. S., Nashville, TN, 37232, USA
| | - David J Calkins
- Vanderbilt Eye Institute, Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, AA7103 MCN/VUIIS, 1161 21st Ave. S., Nashville, TN, 37232, USA.
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14
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McGrady NR, Pasini S, Baratta RO, Del Buono BJ, Schlumpf E, Calkins DJ. Restoring the Extracellular Matrix: A Neuroprotective Role for Collagen Mimetic Peptides in Experimental Glaucoma. Front Pharmacol 2021; 12:764709. [PMID: 34795592 PMCID: PMC8592892 DOI: 10.3389/fphar.2021.764709] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 10/19/2021] [Indexed: 11/24/2022] Open
Abstract
Optic neuropathies are a major cause of visual disabilities worldwide, causing irreversible vision loss through the degeneration of retinal ganglion cell (RGC) axons, which comprise the optic nerve. Chief among these is glaucoma, in which sensitivity to intraocular pressure (IOP) leads to RGC axon dysfunction followed by outright degeneration of the optic projection. Current treatments focus entirely on lowering IOP through topical hypotensive drugs, surgery to facilitate aqueous fluid outflow, or both. Despite this investment in time and resources, many patients continue to lose vision, underscoring the need for new therapeutics that target neurodegeneration directly. One element of progression in glaucoma involves matrix metalloproteinase (MMP) remodeling of the collagen-rich extracellular milieu of RGC axons as they exit the retina through the optic nerve head. Thus, we investigated the ability of collagen mimetic peptides (CMPs) representing various single strand fractions of triple helix human type I collagen to protect RGC axons in an inducible model of glaucoma. First, using dorsal root ganglia maintained in vitro on human type I collagen, we found that multiple CMPs significantly promote neurite outgrowth (+35%) compared to vehicle following MMP-induced fragmentation of the α1(I) and α2(I) chains. We then applied CMP to adult mouse eyes in vivo following microbead occlusion to elevate IOP and determined its influence on anterograde axon transport to the superior colliculus, the primary RGC projection target in rodents. In glaucoma models, sensitivity to IOP causes early degradation in axon function, including anterograde transport from retina to central brain targets. We found that CMP treatment rescued anterograde transport following a 3-week +50% elevation in IOP. These results suggest that CMPs generally may represent a novel therapeutic to supplement existing treatments or as a neuroprotective option for patients who do not respond to IOP-lowering regimens.
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Affiliation(s)
- Nolan R McGrady
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Silvia Pasini
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, United States
| | | | | | - Eric Schlumpf
- Stuart Therapeutics, Inc., Stuart, FL, United States
| | - David J Calkins
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, United States
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15
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Miralles de Imperial-Ollero JA, Gallego-Ortega A, Ortín-Martínez A, Villegas-Pérez MP, Valiente-Soriano FJ, Vidal-Sanz M. Animal Models of LED-Induced Phototoxicity. Short- and Long-Term In Vivo and Ex Vivo Retinal Alterations. Life (Basel) 2021; 11:life11111137. [PMID: 34833013 PMCID: PMC8617611 DOI: 10.3390/life11111137] [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: 10/09/2021] [Revised: 10/20/2021] [Accepted: 10/21/2021] [Indexed: 12/26/2022] Open
Abstract
Phototoxicity animal models have been largely studied due to their degenerative communalities with human pathologies, e.g., age-related macular degeneration (AMD). Studies have documented not only the effects of white light exposure, but also other wavelengths using LEDs, such as blue or green light. Recently, a blue LED-induced phototoxicity (LIP) model has been developed that causes focal damage in the outer layers of the superior-temporal region of the retina in rodents. In vivo studies described a progressive reduction in retinal thickness that affected the most extensively the photoreceptor layer. Functionally, a transient reduction in a- and b-wave amplitude of the ERG response was observed. Ex vivo studies showed a progressive reduction of cones and an involvement of retinal pigment epithelium cells in the area of the lesion and, in parallel, an activation of microglial cells that perfectly circumscribe the damage in the outer retinal layer. The use of neuroprotective strategies such as intravitreal administration of trophic factors, e.g., basic fibroblast growth factor (bFGF), brain-derived neurotrophic factor (BDNF), ciliary neurotrophic factor (CNTF) or pigment epithelium-derived factor (PEDF) and topical administration of the selective alpha-2 agonist (Brimonidine) have demonstrated to increase the survival of the cone population after LIP.
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Affiliation(s)
- Juan A. Miralles de Imperial-Ollero
- Departamento de Oftalmología, Universidad de Murcia e Instituto Murciano de Investigación Biosanitaria (IMIB) Virgen de la Arrixaca, Campus de CC de la Salud, El Palmar, 30120 Murcia, Spain; (J.A.M.d.I.-O.); (A.G.-O.); (M.P.V.-P.)
| | - Alejandro Gallego-Ortega
- Departamento de Oftalmología, Universidad de Murcia e Instituto Murciano de Investigación Biosanitaria (IMIB) Virgen de la Arrixaca, Campus de CC de la Salud, El Palmar, 30120 Murcia, Spain; (J.A.M.d.I.-O.); (A.G.-O.); (M.P.V.-P.)
| | - Arturo Ortín-Martínez
- Donald K. Johnson Eye Institute, Krembil Research Institute, University Health Network, Toronto, ON M5T 2S8, Canada;
| | - María Paz Villegas-Pérez
- Departamento de Oftalmología, Universidad de Murcia e Instituto Murciano de Investigación Biosanitaria (IMIB) Virgen de la Arrixaca, Campus de CC de la Salud, El Palmar, 30120 Murcia, Spain; (J.A.M.d.I.-O.); (A.G.-O.); (M.P.V.-P.)
| | - Francisco J. Valiente-Soriano
- Departamento de Oftalmología, Universidad de Murcia e Instituto Murciano de Investigación Biosanitaria (IMIB) Virgen de la Arrixaca, Campus de CC de la Salud, El Palmar, 30120 Murcia, Spain; (J.A.M.d.I.-O.); (A.G.-O.); (M.P.V.-P.)
- Correspondence: (F.J.V.-S.); (M.V.-S.); Tel.: +34-868-88-4503 (F.J.V-S.); +34-868-88-4330 (M.V.-S.)
| | - Manuel Vidal-Sanz
- Departamento de Oftalmología, Universidad de Murcia e Instituto Murciano de Investigación Biosanitaria (IMIB) Virgen de la Arrixaca, Campus de CC de la Salud, El Palmar, 30120 Murcia, Spain; (J.A.M.d.I.-O.); (A.G.-O.); (M.P.V.-P.)
- Correspondence: (F.J.V.-S.); (M.V.-S.); Tel.: +34-868-88-4503 (F.J.V-S.); +34-868-88-4330 (M.V.-S.)
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16
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A Comparison of Hyper-Reflective Retinal Spot Counts in Optical Coherence Tomography Images from Glaucomatous and Healthy Eyes. J Clin Med 2021; 10:jcm10204668. [PMID: 34682789 PMCID: PMC8538917 DOI: 10.3390/jcm10204668] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 10/03/2021] [Accepted: 10/07/2021] [Indexed: 01/24/2023] Open
Abstract
Purpose: To compare the number of hyper-reflective retinal spots (HRS) in optical coherence tomography (OCT) images of healthy controls and patients affected with primary open angle glaucoma (POAG). Methods: Thirty patients affected with POAG and 34 healthy controls were recruited and underwent raster OCT examination of the macular region. Among the acquired B-scans, the one with the lowest foveal thickness was selected, and a central area of 3000 μm was defined (region of interest, ROI), in order to identify HRS. HRS were defined as small point-like hyper-reflective elements, detectable at the visual inspection of the OCT image. HRS were independently counted by two investigators in the ROI of each OCT scan. Results: Inter-rater agreement for HRS counting was good to excellent (ICC = 0.96, 95% CI: 0.83–0.99). More HRS were found in the OCT images from glaucoma patients, in comparison with healthy controls (average value: 90.5 ± 13.02 and 74.72 ± 11.35, for glaucoma and healthy subjects, respectively; p < 0.01). Significant correlations between the average number of HRS and visual field mean deviation (MD, p = 0.01) and pattern standard deviation (PSD, p < 0.01) were found. Conclusions: OCT images from glaucoma patients showed a higher number of HRS when compared with healthy controls. As HRS have been hypothesized to be a sign of neuroinflammation, these results may support the role of neuroinflammation in glaucoma etiopathogenesis.
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17
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Conti F, Romano GL, Eandi CM, Toro MD, Rejdak R, Di Benedetto G, Lazzara F, Bernardini R, Drago F, Cantarella G, Bucolo C. Brimonidine is Neuroprotective in Animal Paradigm of Retinal Ganglion Cell Damage. Front Pharmacol 2021; 12:705405. [PMID: 34366858 PMCID: PMC8333612 DOI: 10.3389/fphar.2021.705405] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 07/07/2021] [Indexed: 12/20/2022] Open
Abstract
To investigate the neuroprotective effect of brimonidine after retinal ischemia damage on mouse eye. Glaucoma is an optic neuropathy characterized by retinal ganglion cells (RGCs) death, irreversible peripheral and central visual field loss, and high intraocular pressure. Ischemia reperfusion (I/R) injury model was used in C57BL/6J mice to mimic conditions of glaucomatous neurodegeneration. Mouse eyes were treated topically with brimonidine and pattern electroretinogram were used to assess the retinal ganglion cells (RGCs) function. A wide range of inflammatory markers, as well as anti-inflammatory and neurotrophic molecules, were investigated to figure out the potential protective effects of brimonidine in mouse retina. In particular, brain-derived neurotrophic factor (BDNF), IL-6, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and its death receptor DR-5, TNF-α, GFAP, Iba-1, NOS, IL-1β and IL-10 were assessed in mouse retina that underwent to I/R insult with or without brimonidine treatment. Brimonidine provided remarkable RGCs protection in our paradigm. PERG amplitude values were significantly (p < 0.05) higher in brimonidine-treated eyes in comparison to I/R retinas. Retinal BDNF mRNA levels in the I/R group dropped significantly (p < 0.05) compared to the control group (normal mice); brimonidine treatment counteracted the downregulation of retinal BDNF mRNA in I/R eyes. Retinal inflammatory markers increased significantly (p < 0.05) in the I/R group and brimonidine treatment was able to revert that. The anti-inflammatory IL-10 decreased significantly (p < 0.05) after retinal I/R insult and increased significantly (p < 0.05) in the group treated with brimonidine. In conclusion, brimonidine was effective in preventing loss of function of RGCs and in regulating inflammatory biomarkers elicited by retinal I/R injury.
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Affiliation(s)
- Federica Conti
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania, Catania, Italy
| | - Giovanni Luca Romano
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania, Catania, Italy
| | - Chiara Maria Eandi
- Department of Ophthalmology, Jules Gonin Eye Hospital, Fondation Asile des Aveugles, University of Lausanne, Lausanne, Switzerland
| | - Mario Damiano Toro
- Department of Ophthalmology, University of Zurich, Zurich, Switzerland.,Chair and Department of General and Pediatric Ophthalmology, Medical University of Lublin, Lublin, Poland
| | - Robert Rejdak
- Chair and Department of General and Pediatric Ophthalmology, Medical University of Lublin, Lublin, Poland
| | - Giulia Di Benedetto
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania, Catania, Italy
| | - Francesca Lazzara
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania, Catania, Italy
| | - Renato Bernardini
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania, Catania, Italy
| | - Filippo Drago
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania, Catania, Italy
| | - Giuseppina Cantarella
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania, Catania, Italy
| | - Claudio Bucolo
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania, Catania, Italy
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18
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Takahashi N, Matsunaga N, Natsume T, Kitazawa C, Itani Y, Hama A, Hayashi I, Shimazawa M, Hara H, Takamatsu H. A longitudinal comparison in cynomolgus macaques of the effect of brimonidine on optic nerve neuropathy using diffusion tensor imaging magnetic resonance imaging and spectral domain optical coherence tomography. Heliyon 2021; 7:e06701. [PMID: 33898826 PMCID: PMC8056221 DOI: 10.1016/j.heliyon.2021.e06701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 01/04/2021] [Accepted: 03/31/2021] [Indexed: 10/26/2022] Open
Abstract
Early detection of optic neuropathy is crucial for initiating treatment that could delay or prevent visual field loss. Preclinical studies have advanced a number of potential neuroprotective strategies to prevent retinal ganglion cell (RGC) degeneration, but none have successfully completed clinical trials. One issue related to the lack of preclinical to clinical translation is the lack of preclinical morphometric assessments that could be used to track neuroprotection, as well as neurodegeneration, over time within the same animal. Thus, to assess whether clinically used morphometric assessments can identify neuroprotection of RGC, the current study compared optic nerve fractional anisotropy (FA) obtained with diffusion tensor imaging (DTI) and retinal nerve fiber layer (RNFL) thickness measured with spectral domain optical coherence tomography (SD-OCT) to observe not only the early progression of RGC axonal degeneration but to also discern which imaging modality identifies signs of neuroprotection during treatment with the alpha-adrenoceptor agonist brimonidine. Elevated and sustained intraocular pressure (IOP) was observed following laser photocoagulation of the trabecular meshwork in one eye of nonhuman primates (NHP). Either brimonidine (0.1%) or control treatment was instilled twice daily for two months. In control-treated eyes, increased IOP, increased vertical cup-to-disc (C/D), reduced rim-to-disc (R/D) ratio, decreased RNFL thickness and decreased FA were observed. While IOP remained elevated during the course of the study, brimonidine tended to delay the progression of RNFL thinning. However, in the same animal, optic nerve FA did not appear to decline. Brimonidine treatment did not affect other measures of RGC axonal degeneration. The current findings demonstrate that early progression of optic neuropathy can be tracked over time in a nonhuman primate model of ocular hypertension using either DTI or SD-OCT. Furthermore, the delayed changes to RNFL thickness and FA appear to be a neuroprotective effect of brimonidine independent of its effect on IOP.
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Affiliation(s)
- Nobuyuki Takahashi
- Pharmacology, Hamamatsu Pharma Research, Inc., 1-3-7, Shinmiyakoda, Kita-ku, Hamamatsu, Shizuoka, 431-2103, Japan
| | - Naoko Matsunaga
- Pharmacology, Hamamatsu Pharma Research, Inc., 1-3-7, Shinmiyakoda, Kita-ku, Hamamatsu, Shizuoka, 431-2103, Japan
| | - Takahiro Natsume
- Pharmacology, Hamamatsu Pharma Research, Inc., 1-3-7, Shinmiyakoda, Kita-ku, Hamamatsu, Shizuoka, 431-2103, Japan
| | - Chinatsu Kitazawa
- Pharmacology, Hamamatsu Pharma Research, Inc., 1-3-7, Shinmiyakoda, Kita-ku, Hamamatsu, Shizuoka, 431-2103, Japan
| | - Yoshitaka Itani
- Pharmacology, Hamamatsu Pharma Research, Inc., 1-3-7, Shinmiyakoda, Kita-ku, Hamamatsu, Shizuoka, 431-2103, Japan
| | - Aldric Hama
- Pharmacology, Hamamatsu Pharma Research, Inc., 1-3-7, Shinmiyakoda, Kita-ku, Hamamatsu, Shizuoka, 431-2103, Japan
| | - Ikuo Hayashi
- Hamamatsu Pharma Research USA, Inc., 4660 La Jolla Village Drive, San Diego, CA, 92122 USA
| | - Masamitsu Shimazawa
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu 501-1196, Japan
| | - Hideaki Hara
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu 501-1196, Japan
| | - Hiroyuki Takamatsu
- Pharmacology, Hamamatsu Pharma Research, Inc., 1-3-7, Shinmiyakoda, Kita-ku, Hamamatsu, Shizuoka, 431-2103, Japan
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19
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Hopper RG, Montiani-Ferreira F, da Silva Pereira J, Fritz MC, Ruggiero VJ, Sapienza JS, Kato K, Komáromy AM. Presumed neuroprotective therapies prescribed by veterinary ophthalmologists for canine degenerative retinal and optic nerve diseases. Vet Ophthalmol 2021; 24:229-239. [PMID: 33682296 DOI: 10.1111/vop.12878] [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: 09/11/2020] [Revised: 02/13/2021] [Accepted: 02/13/2021] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To investigate veterinary ophthalmologists' use of presumed neuroprotective therapies for degenerative retinal and optic nerve diseases in dogs. PROCEDURES An online survey was sent to 663 board-certified veterinary ophthalmologists who were Diplomates of the American College of Veterinary Ophthalmologists (ACVO), Asian College of Veterinary Ophthalmologists (AiCVO), Latin American College of Veterinary Ophthalmologists (Colegio Latinoamericano de Oftalmólogos Veterinarios, CLOVE), or European College of Veterinary Ophthalmologists (ECVO). The survey was created using Qualtrics® software and focused on the prescription of presumed neuroprotective treatments for canine glaucoma, sudden acquired retinal degeneration syndrome (SARDS), progressive retinal atrophy (PRA), and retinal detachment (RD). RESULTS A total of 165 completed surveys were received, representing an overall response rate of 25%, which was comparable across the four specialty colleges. Of all respondents, 140/165 (85%) prescribed some form of presumed neuroprotective therapies at least once in the last five years: 114/165 (69%) for glaucoma, 51/165 (31%) for SARDS, 116/165 (70%) for PRA, and 50/165 (30%) for RD. The three most recommended neuroprotective reagents were the commercial Ocu-GLO™ Vision Supplement for animals, amlodipine, and human eye supplements. CONCLUSIONS Despite lack of published clinical efficacy data, the majority of surveyed board-certified veterinary ophthalmologists previously prescribed a presumed neuroprotective therapy at least once in the last five years in dogs with degenerative retinal and optic nerve diseases.
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Affiliation(s)
- Ryan G Hopper
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI, USA
| | | | - Jorge da Silva Pereira
- Center of Studies, Research, and Veterinary Ophthalmology (CEPOV), Rio de Janeiro, Brazil
| | - Michele C Fritz
- Office of Academic Programs, College of Veterinary Medicine, Michigan State University, East Lansing, MI, USA
| | - Vickie J Ruggiero
- Office of Academic Programs, College of Veterinary Medicine, Michigan State University, East Lansing, MI, USA
| | | | | | - András M Komáromy
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI, USA
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20
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Rodrigo MJ, Cardiel MJ, Fraile JM, Mendez-Martinez S, Martinez-Rincon T, Subias M, Polo V, Ruberte J, Ramirez T, Vispe E, Luna C, Mayoral JA, Garcia-Martin E. Brimonidine-LAPONITE® intravitreal formulation has an ocular hypotensive and neuroprotective effect throughout 6 months of follow-up in a glaucoma animal model. Biomater Sci 2020; 8:6246-6260. [PMID: 33016285 DOI: 10.1039/d0bm01013h] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Intravitreal administration is widely used in ophthalmological practice to maintain therapeutic drug levels near the neuroretina and because drug delivery systems are necessary to avoid reinjections and sight-threatening side effects. However, currently there is no intravitreal treatment for glaucoma. The brimonidine-LAPONITE® formulation was created with the aim of treating glaucoma for extended periods with a single intravitreal injection. Glaucoma was induced by producing ocular hypertension in two rat cohorts: [BRI-LAP] and [non-bri], with and without treatment, respectively. Eyes treated with brimonidine-LAPONITE® showed lower ocular pressure levels up to week 8 (p < 0.001), functional neuroprotection explored by scotopic and photopic negative response electroretinography (p = 0.042), and structural protection of the retina, retinal nerve fibre layer and ganglion cell layer (p = 0.038), especially on the superior-inferior axis explored by optical coherence tomography, which was corroborated by a higher retinal ganglion cell count (p = 0.040) using immunohistochemistry (Brn3a antibody) up to the end of the study (week 24). Furthermore, delayed neuroprotection was detected in the contralateral eye. Brimonidine was detected in treated rat eyes for up to 6 months. Brimonidine-LAPONITE® seems to be a potential sustained-delivery intravitreal drug for glaucoma treatment.
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Affiliation(s)
- M J Rodrigo
- Department of Ophthalmology, Miguel Servet University Hospital, Zaragoza, Spain.
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Scuteri D, Bagetta G, Nucci C, Aiello F, Cesareo M, Tonin P, Corasaniti MT. Evidence on the neuroprotective properties of brimonidine in glaucoma. PROGRESS IN BRAIN RESEARCH 2020; 257:155-166. [PMID: 32988470 DOI: 10.1016/bs.pbr.2020.07.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND glaucoma is the leading cause of irreversible blindness all over the world. The degree of visual field loss accounts for the severity of the disease and represents the main clinical outcome of treatment for patients affected by glaucoma. The α2 agonists, like brimonidine, emerged in the 1960s as topical ophthalmologic treatment. Their neuroprotective mechanism in glaucoma is still debated, ranging from effect on extracellular glutamate, to ocular hypotension and blood flow. OBJECTIVES this systematic review and meta-analysis aims at assessing the efficacy of brimonidine on visual field deterioration during glaucoma through the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) approach. Databases consulted: the literature search has been performed on PubMed, MEDLINE, ClinicalTrials.gov and Scopus up to June 10th, 2020. Study eligibility criteria, participants, and interventions: clinical trials assessing the effects of brimonidine on visual field in patients with glaucoma. Study appraisal: the eligibility of the studies has been assessed by two independent authors and the selection has followed the PRISMA flow diagram. The retrieved results have been subjected to risk of bias evaluation. RESULTS the search of literature has retrieved 418 papers, among which 5 are eligible for inclusion in the qualitative analysis. All the studies present high heterogeneity, therefore meta-analysis has not been possible. The results obtained suggest that brimonidine improves visual field, but the design of the clinical trials rises some concerns in terms of risk of bias. CONCLUSIONS the evidence of neuroprotective effect of brimonidine is inconclusive and needs stronger support. Large double-blind randomized clinical trials are necessary to strengthen this evidence.
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Affiliation(s)
- Damiana Scuteri
- Pharmacotechnology Documentation and Transfer Unit, Preclinical and Translational Pharmacology, Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Rende, Italy
| | - Giacinto Bagetta
- Pharmacotechnology Documentation and Transfer Unit, Preclinical and Translational Pharmacology, Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Rende, Italy.
| | - Carlo Nucci
- Ophthalmology Unit, Department of Experimental Medicine, University of Rome Tor Vergata, Rome, Italy
| | - Francesco Aiello
- Ophthalmology Unit, Department of Experimental Medicine, University of Rome Tor Vergata, Rome, Italy
| | - Massimo Cesareo
- Ophthalmology Unit, Department of Experimental Medicine, University of Rome Tor Vergata, Rome, Italy
| | - Paolo Tonin
- Regional Center for Serious Brain Injuries, S. Anna Institute, Crotone, Italy
| | - Maria Tiziana Corasaniti
- School of Hospital Pharmacy, University "Magna Graecia" of Catanzaro and Department of Health Sciences, University "Magna Graecia" of Catanzaro, Catanzaro, Italy
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22
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Lambert WS, Pasini S, Collyer JW, Formichella CR, Ghose P, Carlson BJ, Calkins DJ. Of Mice and Monkeys: Neuroprotective Efficacy of the p38 Inhibitor BIRB 796 Depends on Model Duration in Experimental Glaucoma. Sci Rep 2020; 10:8535. [PMID: 32444682 PMCID: PMC7244559 DOI: 10.1038/s41598-020-65374-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 05/04/2020] [Indexed: 01/23/2023] Open
Abstract
Glaucoma is a group of optic neuropathies associated with aging and sensitivity to intraocular pressure (IOP). Early progression involves retinal ganglion cell (RGC) axon dysfunction that precedes frank degeneration. Previously we demonstrated that p38 MAPK inhibition abates axonal dysfunction and slows degeneration in the inducible microbead occlusion model of glaucoma in rat. Here, we assessed the neuroprotective effect of topical eye delivery of the p38 MAPK inhibitor BIRB 796 in three models of glaucoma (microbead occlusion in rat and squirrel monkey and the genetic DBA/2 J mouse model) with distinct durations of IOP elevation. While BIRB 796 did not influence IOP, treatment over four weeks in rats prevented degradation of anterograde axonal transport to the superior colliculus and degeneration in the optic nerve. Treatment over months in the chronic DBA/2 J model and in the squirrel monkey model reduced expression and activation of p38 downstream targets in the retina and brain but did not rescue RGC axon transport or degeneration, suggesting the efficacy of BIRB 796 in preventing associated degeneration of the RGC projection depends on the duration of the experimental model. These results emphasize the importance of evaluating potential therapeutic compounds for neuroprotection in multiple models using elongated treatment paradigms for an accurate assessment of efficacy.
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Affiliation(s)
- Wendi S Lambert
- The Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, 37232-2337, USA
| | - Silvia Pasini
- The Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, 37232-2337, USA
| | - John W Collyer
- The Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, 37232-2337, USA
| | - Cathryn R Formichella
- The Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, 37232-2337, USA
| | - Purnima Ghose
- The Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, 37232-2337, USA
| | - Brian J Carlson
- The Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, 37232-2337, USA
| | - David J Calkins
- The Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, 37232-2337, USA.
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23
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Cimolai N. A review of neuropsychiatric adverse events from topical ophthalmic brimonidine. Hum Exp Toxicol 2020; 39:1279-1290. [DOI: 10.1177/0960327120918307] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Brimonidine is a first-line topical medication for increased intraocular pressure and glaucoma which may be used alone or in conjunction with other topical therapies. Its structural and pharmacological comparabilities to clonidine give way to the hypothesis that it may cause neuropsychiatric side effects. The majority of case reports citing brimonidine toxicity, either for topical or peripheral exposure, include pediatric age groups but especially infants. Among the latter, a dose-response phenomenon is evident. Dose-response correlates have also been shown among adults. Case series and prospective double-blind treatment studies also give evidence for the occurrence of several central nervous system adverse reactions. Topical ophthalmic brimonidine use should be followed for the occurrence of neuropsychiatric disturbances generally, and enhanced vigilance should be maintained for at-risk populations.
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Affiliation(s)
- N Cimolai
- Faculty of Medicine, The University of British Columbia, Vancouver, BC, Canada
- Children’s and Women’s Health Centre of British Columbia, Vancouver, BC, Canada
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24
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Neuroprotective Strategies for Retinal Ganglion Cell Degeneration: Current Status and Challenges Ahead. Int J Mol Sci 2020; 21:ijms21072262. [PMID: 32218163 PMCID: PMC7177277 DOI: 10.3390/ijms21072262] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 03/19/2020] [Accepted: 03/20/2020] [Indexed: 12/12/2022] Open
Abstract
The retinal ganglion cells (RGCs) are the output cells of the retina into the brain. In mammals, these cells are not able to regenerate their axons after optic nerve injury, leaving the patients with optic neuropathies with permanent visual loss. An effective RGCs-directed therapy could provide a beneficial effect to prevent the progression of the disease. Axonal injury leads to the functional loss of RGCs and subsequently induces neuronal death, and axonal regeneration would be essential to restore the neuronal connectivity, and to reestablish the function of the visual system. The manipulation of several intrinsic and extrinsic factors has been proposed in order to stimulate axonal regeneration and functional repairing of axonal connections in the visual pathway. However, there is a missing point in the process since, until now, there is no therapeutic strategy directed to promote axonal regeneration of RGCs as a therapeutic approach for optic neuropathies.
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25
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Pang IH, Clark AF. Inducible rodent models of glaucoma. Prog Retin Eye Res 2020; 75:100799. [PMID: 31557521 PMCID: PMC7085984 DOI: 10.1016/j.preteyeres.2019.100799] [Citation(s) in RCA: 83] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 09/16/2019] [Accepted: 09/18/2019] [Indexed: 11/23/2022]
Abstract
Glaucoma is one of the leading causes of vision impairment worldwide. In order to further understand the molecular pathobiology of this disease and to develop better therapies, clinically relevant animal models are necessary. In recent years, both the rat and mouse have become popular models in glaucoma research. Key reasons are: many important biological similarities shared among rodent eyes and the human eye; development of improved methods to induce glaucoma and to evaluate glaucomatous damage; availability of genetic tools in the mouse; as well as the relatively low cost of rodent studies. Commonly studied rat and mouse glaucoma models include intraocular pressure (IOP)-dependent and pressure-independent models. The pressure-dependent models address the most important risk factor of elevated IOP, whereas the pressure-independent models assess "normal tension" glaucoma and other "non-IOP" related factors associated with glaucomatous damage. The current article provides descriptions of these models, their characterizations, specific techniques to induce glaucoma, mechanisms of injury, advantages, and limitations.
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Affiliation(s)
- Iok-Hou Pang
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, USA; Department of Pharmaceutical Sciences, University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - Abbot F Clark
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, USA; Department of Pharmacology & Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas, USA.
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26
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Zhou X, Zhang T, Wu J. Brimonidine enhances inhibitory postsynaptic activity of OFF- and ON-type retinal ganglion cells in a Wistar rat chronic glaucoma model. Exp Eye Res 2019; 189:107833. [PMID: 31618613 DOI: 10.1016/j.exer.2019.107833] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Revised: 06/07/2019] [Accepted: 10/09/2019] [Indexed: 10/25/2022]
Abstract
Glaucoma is a multifactorial disease in which retinal ganglion cells (RGCs) undergo excitotoxic damage, leading to their degeneration. The α2-adrenoceptor (α2-AR) agonist brimonidine exerts a neuroprotective effect by regulating postsynaptic excitatory N-methyl-D-aspartate (NMDA) receptor activity in RGCs. However, researchers have not clearly determined whether or how brimonidine regulates inhibitory synaptic transmission in rat models of chronic glaucoma. Whole-cell voltage-clamp and current-clamp recordings were performed in ON- and OFF-type RGCs in retinal slices. Brimonidine directly and acutely enhanced γ-aminobutyric acidergic (GABAergic) transmission mediated by ionotropic GABAA receptors in ON- and OFF-type RGCs in rat retinal slices; this effect occurred at the synaptic terminals and was independent of action potentials and multi-synaptic connections. The highly selective α2-AR antagonist yohimbine blocked the effects of brimonidine. Regarding the postsynaptic GABA receptor sensitivity, brimonidine also increased the amplitude of the GABA-induced current. Additionally, compared to RGCs from the control group, the frequencies and amplitudes of spontaneous excitatory postsynaptic currents (sEPSCs) and miniature excitatory postsynaptic currents (mEPSCs) did not change after brimonidine gravity perfusion. Brimonidine significantly decreased the spontaneous firing frequency of rat RGCs with intact synaptic inputs and decreased the resting membrane potential of RGCs, changes that were blocked by the highly selective GABAA receptor antagonist SR95531. SR95531 alone increased spontaneous action potentials and the resting membrane potential. Based on these findings, an α2-AR agonist facilitated the frequency of the GABAergic inhibitory postsynaptic currents (IPSCs), directly increased the amplitude of the postsynaptic GABA-induced current (GABA receptor reactivity/sensitivity), suppressed the firing frequency of spontaneous action in RGCs with intact synaptic inputs and decreased the resting membrane potential of RGCs, thus deactivating RGCs from the neural network level and reducing the excitotoxic damage occurring during the pathological process of chronic glaucoma.
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Affiliation(s)
- Xujiao Zhou
- Eye Institute, Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Shanghai Medical College, Fudan University, Shanghai, 200032, China; Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, 200032, China; NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences (Fudan University), Shanghai, 200032, China.
| | - Ting Zhang
- Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, 200032, China; NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences (Fudan University), Shanghai, 200032, China; Research Center, Eye & ENT Hospital, Fudan University, Shanghai, 200032, China.
| | - Jihong Wu
- Eye Institute, Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Shanghai Medical College, Fudan University, Shanghai, 200032, China; Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, 200032, China; NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences (Fudan University), Shanghai, 200032, China; Department of Ophthalmology and Vision Science, Eye & ENT Hospital, Fudan University, Shanghai, 200032, China.
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Claes M, De Groef L, Moons L. Target-Derived Neurotrophic Factor Deprivation Puts Retinal Ganglion Cells on Death Row: Cold Hard Evidence and Caveats. Int J Mol Sci 2019; 20:E4314. [PMID: 31484425 PMCID: PMC6747494 DOI: 10.3390/ijms20174314] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 08/28/2019] [Accepted: 08/30/2019] [Indexed: 12/14/2022] Open
Abstract
Glaucoma and other optic neuropathies are characterized by axonal transport deficits. Axonal cargo travels back and forth between the soma and the axon terminus, a mechanism ensuring homeostasis and the viability of a neuron. An example of vital molecules in the axonal cargo are neurotrophic factors (NTFs). Hindered retrograde transport can cause a scarcity of those factors in the retina, which in turn can tilt the fate of retinal ganglion cells (RGCs) towards apoptosis. This postulation is one of the most widely recognized theories to explain RGC death in the disease progression of glaucoma and is known as the NTF deprivation theory. For several decades, research has been focused on the use of NTFs as a novel neuroprotective glaucoma treatment. Until now, results in animal models have been promising, but translation to the clinic has been highly disappointing. Are we lacking important knowledge to lever NTF therapies towards the therapeutic armamentarium? Or did we get the wrong end of the stick regarding the NTF deprivation theory? In this review, we will tackle the existing evidence and caveats advocating for and against the target-derived NTF deprivation theory in glaucoma, whilst digging into associated therapy efforts.
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Affiliation(s)
- Marie Claes
- Laboratory of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, 3000 Leuven, Belgium
| | - Lies De Groef
- Laboratory of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, 3000 Leuven, Belgium
| | - Lieve Moons
- Laboratory of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, 3000 Leuven, Belgium.
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28
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Bernardo-Colón A, Vest V, Cooper ML, Naguib SA, Calkins DJ, Rex TS. Progression and Pathology of Traumatic Optic Neuropathy From Repeated Primary Blast Exposure. Front Neurosci 2019; 13:719. [PMID: 31354422 PMCID: PMC6637732 DOI: 10.3389/fnins.2019.00719] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 06/26/2019] [Indexed: 01/01/2023] Open
Abstract
Indirect traumatic optic neuropathy (ITON) is a condition that is often associated with traumatic brain injury and can result in significant vision loss due to degeneration of retinal ganglion cell (RGC) axons at the time of injury or within the ensuing weeks. We used a mouse model of eye-directed air-blast exposure to characterize the histopathology of blast-induced ITON. This injury caused a transient elevation of intraocular pressure with subsequent RGC death and axon degeneration that was similar throughout the length of the optic nerve (ON). Deficits in active anterograde axon transport to the superior colliculus accompanied axon degeneration and first appeared in peripheral representations of the retina. Glial area in the ON increased early after injury and involved a later period of additional expansion. The increase in area involved a transient change in astrocyte organization independent of axon degeneration. While levels of many cytokines and chemokines did not change, IL-1α and IL-1β increased in both the ON and retina. In contrast, glaucoma shows distal to proximal axon degeneration with astrocyte remodeling and increases in many cytokines and chemokines. Further, direct traumatic optic neuropathies have a clear site of injury with rapid, progressive axon degeneration and cell death. These data show that blast-induced ITON is a distinct neuropathology from other optic neuropathies.
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Affiliation(s)
| | - Victoria Vest
- Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Melissa L. Cooper
- Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Sarah A. Naguib
- Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - David J. Calkins
- Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, United States
- Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Tonia S. Rex
- Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, United States
- Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, Nashville, TN, United States
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Shamsher E, Davis BM, Yap TE, Guo L, Cordeiro MF. Neuroprotection in glaucoma: old concepts, new ideas. EXPERT REVIEW OF OPHTHALMOLOGY 2019. [DOI: 10.1080/17469899.2019.1604222] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Ehtesham Shamsher
- Department of Visual Neuroscience, University College London Institute of Ophthalmology, London, UK
| | - Benjamin M. Davis
- Department of Visual Neuroscience, University College London Institute of Ophthalmology, London, UK
- The Imperial College Ophthalmic Research Group (ICORG), Imperial College London, London
| | - Timothy E. Yap
- The Imperial College Ophthalmic Research Group (ICORG), Imperial College London, London
- The Western Eye Hospital, Imperial College Healthcare NHS Trust, London, UK
| | - Li Guo
- Department of Visual Neuroscience, University College London Institute of Ophthalmology, London, UK
| | - Maria Francesca Cordeiro
- Department of Visual Neuroscience, University College London Institute of Ophthalmology, London, UK
- The Imperial College Ophthalmic Research Group (ICORG), Imperial College London, London
- The Western Eye Hospital, Imperial College Healthcare NHS Trust, London, UK
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30
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Effect of Solution pH on Distribution of Ophthalmically Administered Brimonidine in Posterior Ocular Tissues in Pigmented Rabbits. Ophthalmol Ther 2019; 8:271-277. [PMID: 30891685 PMCID: PMC6514203 DOI: 10.1007/s40123-019-0180-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Indexed: 10/27/2022] Open
Abstract
INTRODUCTION Brimonidine bioavailability in the aqueous humor depends on the solution pH following topical administration. The purpose of this study was to investigate the effect of solution pH on brimonidine distribution in the posterior ocular tissues in pigmented rabbits. METHODS The anterior retina/choroid, posterior retina/choroid, and vitreous body of pigmented rabbits were collected 0.67, 1.5, 3, 6, 12, 24, 168, and 360 h after the administration of a single topical dose of 0.2% brimonidine tartrate ophthalmic solution, pH 6.4 (Alphagan®; Allergan Inc., Irvine, CA, USA). Brimonidine concentrations in these tissues were quantified using liquid chromatography/tandem mass spectrometry. Pharmacokinetic parameters were determined using noncompartmental analysis, and the results were compared with tissues from eyes administered 0.1% brimonidine tartrate ophthalmic solution, pH 7.3 (Aiphagan®; Senju Pharmaceutical Co., Ltd., Osaka, Japan) in our previous study conducted using the same procedure. RESULTS Topically applied brimonidine was distributed rapidly into the posterior tissues of the eye after a single ophthalmic administration of the 0.2% ophthalmic solution. The areas under the curve from time 0 to 360 h following dosing with the 0.2% ophthalmic solution were 500,000, 14,300, and 28.7 ng h/g in the anterior and posterior retina/choroid, and vitreous body, respectively. CONCLUSION The differences in the areas under the curve between two ophthalmic solutions were less than the difference in drug concentrations between these two products in any tissues. This finding indicates that the change in the solution pH from 6.4 to 7.3 increases brimonidine bioavailability into the posterior ocular tissues similarly as into the aqueous humor. FUNDING Senju Pharmaceutical Co., Ltd.
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31
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Gandara-Loe J, Ortuño-Lizarán I, Fernández-Sanchez L, Alió JL, Cuenca N, Vega-Estrada A, Silvestre-Albero J. Metal-Organic Frameworks as Drug Delivery Platforms for Ocular Therapeutics. ACS APPLIED MATERIALS & INTERFACES 2019; 11:1924-1931. [PMID: 30561189 DOI: 10.1021/acsami.8b20222] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Metal-organic frameworks (MOFs) have been evaluated as potential nanocarriers for intraocular incorporation of brimonidine tartrate to treat chronic glaucoma. Experimental results show that UiO-67 and MIL-100 (Fe) exhibit the highest loading capacity with values up to 50-60 wt %, whereas the performance is quite limited for MOFs with narrow cavities (below 0.8 nm, for example, UiO-66 and HKUST-1). The large loading capacity in UiO-67 is accompanied by an irreversible structural amorphization in aqueous and physiological media that promotes extended release kinetics above 12 days. Compared to the traditional drawbacks associated with the sudden release of the commercial drugs (e.g., ALPHAGAN), these results anticipate UiO-67 as a potential nanocarrier for drug delivery in intraocular therapeutics. These promising results are further supported by cytotoxicity tests using retinal photoreceptor cells (661W). Toxicity of these structures (including the metal nodes and organic ligands) for retinal cells is rather low for all samples evaluated, except for HKUST-1.
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Affiliation(s)
| | | | | | - Jorge L Alió
- Research and Development Department , VISSUM Corporation , E-03016 Alicante , Spain
| | | | - Alfredo Vega-Estrada
- Research and Development Department , VISSUM Corporation , E-03016 Alicante , Spain
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32
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Cooper ML, Collyer JW, Calkins DJ. Astrocyte remodeling without gliosis precedes optic nerve Axonopathy. Acta Neuropathol Commun 2018; 6:38. [PMID: 29747701 PMCID: PMC5946396 DOI: 10.1186/s40478-018-0542-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 04/26/2018] [Indexed: 11/10/2022] Open
Abstract
Astroyctes serve myriad functions but are especially critical in white matter tracts, where energy-demanding axons propagate action potentials great distances between neurons. Axonal dependence on astrocytes for even normal function accentuates the critical role astrocytes serve during disease. In glaucoma, the most common optic neuropathy, sensitivity to intraocular pressure (IOP) challenges RGC axons early, including degradation of anterograde transport to the superior colliculus (SC). Astrocyte remodeling presages overt axon degeneration in glaucoma and thus may present a therapeutic opportunity. Here we developed a novel metric to quantify organization of astrocyte processes in the optic nerve relative to axon degeneration in the DBA/2 J hereditary mouse model of glaucoma. In early progression, as axons expand prior to loss, astrocyte processes become more parallel with migration to the nerve’s edge without a change in overall coverage of the nerve. As axons degenerate, astrocyte parallelism diminishes with increased glial coverage and reinvasion of the nerve. In longitudinal sections through aged DBA/2 J nerve, increased astrocyte parallelism reflected elevated levels of the astrocyte gap-junction protein connexin 43 (Cx43). In the distal nerve, increased Cx43 also indicated with a higher level of intact anterograde transport from retina to SC. Our results suggest that progression of axonopathy in the optic nerve involves astrocyte remodeling in two phases. In an early phase, astrocyte processes organize in parallel, likely through gap-junction coupling, while a later phase involves deterioration of organization as glial coverage increases and axons are lost.
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33
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Nikkhah H, Garfami KH, Kanavi MR, Nashtaei EM, Karimi S, Soheilian M. Safety threshold of intravitreal clonidine in rabbit's eyes. Int J Ophthalmol 2018; 11:25-30. [PMID: 29375986 DOI: 10.18240/ijo.2018.01.05] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 10/31/2017] [Indexed: 11/23/2022] Open
Abstract
AIM To determine the safe dose of intravitreal clonidine (IVC), a potential drug for neuroprotection and angiogenesis inhibition in rabbits. METHODS A total of 28 rabbits were divided into four groups. Three groups received IVC with concentrations of 15 (Group A), 25 (Group B), and 50 (Group C) µg/0.1 mL and the control group (Group D) received 0.1 mL balanced salt solution (BSS). To investigate IVC safety, electroretinography (ERG) was performed at baseline, then at 1, 4 and 8wk after injection. After last ERG, all rabbits were euthanized, their eyes were enucleated and subjected to routine histopathological evaluation, immunohistochemistry for glial fibrillary acidic protein (GFAP) and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) test. RESULTS Based on ERG, histopathology, GFAP and TUNEL assay findings, 15 µg IVC was determined as the safe dose in rabbit eyes. While, the results of routine histopathology and TUNEL assay were unremarkable in all groups, toxic effects attributed to 25 and 50 µg IVC were demonstrated by ERG and GFAP tests. CONCLUSION Totally 15 µg clonidine is determined as the safe dose for intravitreal injection in rabbits. Contribution of IVC in neuroprotection and inhibition of angiogenesis deserve more studies.
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Affiliation(s)
- Homayoun Nikkhah
- Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran 16666, Iran.,Torfeh Eye Hospital, Shahid Beheshti University of Medical Sciences, Tehran 16666, Iran
| | - Kiumars Heidari Garfami
- Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran 16666, Iran
| | - Mozhgan Rezaei Kanavi
- Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran 16666, Iran.,Ocular Tissue Engineering Research Center, Shahid Beheshti University of Medical Sciences, Tehran 16666, Iran
| | - Ebrahim Mohammad Nashtaei
- Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran 16666, Iran.,Ocular Tissue Engineering Research Center, Shahid Beheshti University of Medical Sciences, Tehran 16666, Iran
| | - Saeed Karimi
- Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran 16666, Iran.,Torfeh Eye Hospital, Shahid Beheshti University of Medical Sciences, Tehran 16666, Iran
| | - Masoud Soheilian
- Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran 16666, Iran.,Ocular Tissue Engineering Research Center, Shahid Beheshti University of Medical Sciences, Tehran 16666, Iran.,Labbafinejad Medical Center, Shahid Beheshti University of Medical Sciences, Tehran 16666, Iran
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34
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Marangoz D, Guzel E, Eyuboglu S, Gumusel A, Seckin I, Ciftci F, Yilmaz B, Yalvac I. Comparison of the neuroprotective effects of brimonidine tartrate and melatonin on retinal ganglion cells. Int Ophthalmol 2017; 38:2553-2562. [PMID: 29159432 DOI: 10.1007/s10792-017-0768-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Accepted: 11/12/2017] [Indexed: 02/07/2023]
Abstract
PURPOSE We aimed to compare the neuroprotective effects of brimonidine tartrate (BRT) and melatonin (MEL) on retinal ganglion cells (RGCs) in a rat glaucoma model. METHODS Thirty-six adult Wistar albino rats were allocated into six groups: control (C), glaucoma (G), BRT, MEL, G + BRT and G + MEL. After establishing the glaucoma model, intraocular pressure (IOP) of all animals measured at day 4 and day 30 was compared statistically with day 0 and day 4, respectively. Prior to sacrification at day 30 for histological evaluation and TUNEL analysis, retrograde labeling of non-apoptotic RGCs with 3% Fluorogold was performed and RGCs were evaluated under fluorescein microscope. RESULTS IOP measurements at day 4 were significantly higher than basal measurements in all glaucoma groups. BRT alone induced a time-dependent decrease in IOP (p < 0.05), while MEL alone failed to reduce IOP. However, both BRT and MEL reduced IOP in the presence of glaucoma at day 30 (p < 0.05). BRT treatment significantly reversed the reduced non-apoptotic RGC counts (p < 0.01) and increased TUNEL-positive RGCs (p < 0.001) to control group levels in the presence of glaucoma. However, no statistical significance was found between groups G and G + MEL considering 3% Fluorogold-labeled cell counts and apoptotic index values. CONCLUSION Our study revealed that systemic administration of BRT also has an IOP reducing effect. MEL has no neuroprotective effect on RGCs; on the other hand, BRT acts as a neuroprotective agent against glaucomatous injury, when applied systemically.
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Affiliation(s)
- Deniz Marangoz
- Department of Ophthalmology, Faculty of Medicine, Yeditepe University, Sakir Kesebir cad. Gazi Umur Pasa sok. No: 28, 34349, Beşiktaş-Istanbul, Turkey.
| | - Elif Guzel
- Department of Histology and Embryology, Cerrahpasa Faculty of Medicine, Istanbul University, Kocamustafapasa cad., 34098, Fatih-Istanbul, Turkey.
| | - Signem Eyuboglu
- Department of Physiology, Faculty of Medicine, Yeditepe University, Inonu mah. Kayisdagi cad. 26 Agustos Yerleskesi, 34755, Istanbul, Turkey
| | - Asli Gumusel
- Department of Histology and Embryology, Cerrahpasa Faculty of Medicine, Istanbul University, Kocamustafapasa cad., 34098, Fatih-Istanbul, Turkey
| | - Ismail Seckin
- Department of Histology and Embryology, Cerrahpasa Faculty of Medicine, Istanbul University, Kocamustafapasa cad., 34098, Fatih-Istanbul, Turkey
| | - Ferda Ciftci
- Department of Ophthalmology, Faculty of Medicine, Yeditepe University, Sakir Kesebir cad. Gazi Umur Pasa sok. No: 28, 34349, Beşiktaş-Istanbul, Turkey
| | - Bayram Yilmaz
- Department of Physiology, Faculty of Medicine, Yeditepe University, Inonu mah. Kayisdagi cad. 26 Agustos Yerleskesi, 34755, Istanbul, Turkey
| | - Ilgaz Yalvac
- Department of Ophthalmology, Faculty of Medicine, Yeditepe University, Sakir Kesebir cad. Gazi Umur Pasa sok. No: 28, 34349, Beşiktaş-Istanbul, Turkey
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He S, Stankowska DL, Ellis DZ, Krishnamoorthy RR, Yorio T. Targets of Neuroprotection in Glaucoma. J Ocul Pharmacol Ther 2017; 34:85-106. [PMID: 28820649 DOI: 10.1089/jop.2017.0041] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Progressive neurodegeneration of the optic nerve and the loss of retinal ganglion cells is a hallmark of glaucoma, the leading cause of irreversible blindness worldwide, with primary open-angle glaucoma (POAG) being the most frequent form of glaucoma in the Western world. While some genetic mutations have been identified for some glaucomas, those associated with POAG are limited and for most POAG patients, the etiology is still unclear. Unfortunately, treatment of this neurodegenerative disease and other retinal degenerative diseases is lacking. For POAG, most of the treatments focus on reducing aqueous humor formation, enhancing uveoscleral or conventional outflow, or lowering intraocular pressure through surgical means. These efforts, in some cases, do not always lead to a prevention of vision loss and therefore other strategies are needed to reduce or reverse the progressive neurodegeneration. In this review, we will highlight some of the ocular pharmacological approaches that are being tested to reduce neurodegeneration and provide some form of neuroprotection.
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Affiliation(s)
- Shaoqing He
- North Texas Eye Research Institute, University of North Texas Health Science Center , Fort Worth, Texas
| | - Dorota L Stankowska
- North Texas Eye Research Institute, University of North Texas Health Science Center , Fort Worth, Texas
| | - Dorette Z Ellis
- North Texas Eye Research Institute, University of North Texas Health Science Center , Fort Worth, Texas
| | - Raghu R Krishnamoorthy
- North Texas Eye Research Institute, University of North Texas Health Science Center , Fort Worth, Texas
| | - Thomas Yorio
- North Texas Eye Research Institute, University of North Texas Health Science Center , Fort Worth, Texas
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36
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Echevarria FD, Formichella CR, Sappington RM. Interleukin-6 Deficiency Attenuates Retinal Ganglion Cell Axonopathy and Glaucoma-Related Vision Loss. Front Neurosci 2017; 11:318. [PMID: 28620279 PMCID: PMC5450377 DOI: 10.3389/fnins.2017.00318] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 05/19/2017] [Indexed: 11/13/2022] Open
Abstract
The pleotropic cytokine interleukin-6 (IL-6) is implicated in retinal ganglion cell (RGC) survival and degeneration, including that associated with glaucoma. IL-6 protects RGCs from pressure-induced apoptosis in vitro. However, it is unknown how IL-6 impacts glaucomatous degeneration in vivo. To study how IL-6 influences glaucomatous RGC axonopathy, accompanying glial reactivity, and resultant deficits in visual function, we performed neural tracing, histological, and neurobehavioral assessments in wildtype (B6;129SF2/J; WT) and IL-6 knock-out mice (B6;129S2-IL6tm1kopf/J; IL-6-/-) after 8 weeks of unilateral or bilateral microbead-induced glaucoma (microbead occlusion model). IOP increased by 20% following microbead injection in both genotypes (p < 0.05). However, deficits in wound healing at the site of corneal injection were noted. In WT mice, elevated IOP produced degenerating axon profiles and decreased axon density in the optic nerve by 15% (p < 0.01). In IL-6-/- mice, axon density in the optic nerve did not differ between microbead- and saline-injected mice (p > 0.05) and degenerating axon profiles were minimal. Preservation of RGC axons was reflected in visual function, where visual acuity decreased significantly in a time-dependent manner with microbead-induced IOP elevation in WT (p < 0.001), but not IL-6-/- mice (p > 0.05). Despite this preservation of RGC axons and visual acuity, both microbead-injected WT and IL-6-/- mice exhibited a 50% decrease in anterograde CTB transport to the superior colliculus, as compared to saline-injected controls (p < 0.01). Assessment of glial reactivity revealed no genotype- or IOP-dependent changes in retinal astrocytes. IOP elevation decreased microglia density and percent retinal area covered in WT mice (p < 0.05), while IL-6-/- mice exhibited only a decrease in density (p < 0.05). Together, our findings indicate that two defining features of RGC axonopathy—axon transport deficits and structural degeneration of axons—likely occur via independent mechanisms. Our data suggest that IL-6 is part of a mechanism that specifically leads to structural degeneration of axons. Furthermore, its absence is sufficient to prevent both structural degeneration of the optic nerve and vision loss. Overall, our work supports the proposition that functional deficits in axon transport represent a therapeutic window for RGC axonopathy and identify IL-6 signaling as a strong target for such a therapeutic.
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Affiliation(s)
| | - Cathryn R Formichella
- Department of Ophthalmology and Visual Sciences, Vanderbilt University School of MedicineNashville, TN, United States.,Vanderbilt Eye Institute, Vanderbilt University Medical CenterNashville, TN, United States
| | - Rebecca M Sappington
- Department of Ophthalmology and Visual Sciences, Vanderbilt University School of MedicineNashville, TN, United States.,Vanderbilt Eye Institute, Vanderbilt University Medical CenterNashville, TN, United States.,Department of Pharmacology, Vanderbilt University School of MedicineNashville, TN, United States
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Jutley G, Luk SM, Dehabadi MH, Cordeiro MF. Management of glaucoma as a neurodegenerative disease. Neurodegener Dis Manag 2017; 7:157-172. [PMID: 28540772 DOI: 10.2217/nmt-2017-0004] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Glaucoma is a neurodegenerative disease with an estimated prevalence of 60 million people, and the most common cause of irreversible blindness worldwide. The mainstay of treatment has been aimed at lowering intraocular pressure, currently the only modifiable risk factor. Unfortunately, despite adequate pressure control, many patients go on to suffer irreversible visual loss. We first briefly examine currently established intraocular pressure lowering-treatments, with a discussion of their roles in neuroprotection as demonstrated by both animal and clinical studies. The review then examines currently available intraocular pressure independent agents that have shown promise for possessing neuroprotective effects in the management of glaucoma. Finally, we explore potential future treatments such as immune-modulation, stem cell therapy and neural regeneration as they may provide further protection against the neurodegenerative processes involved in glaucomatous optic neuropathy.
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Affiliation(s)
- Gurjeet Jutley
- Western Eye Hospital, Imperial College Healthcare Trust, London, UK
| | - Sheila Mh Luk
- Medical Retina, Moorfields Eye Hospital, NHS Foundation Trust, London, UK
| | - Mohammad H Dehabadi
- Glaucoma & Retinal Neurodegeneration Research Group, Visual Neuroscience, UCL Institute of Ophthalmology, London, UK.,Medical Retina, Moorfields Eye Hospital, NHS Foundation Trust, London, UK
| | - M Francesca Cordeiro
- Glaucoma & Retinal Neurodegeneration Research Group, Visual Neuroscience, UCL Institute of Ophthalmology, London, UK.,Western Eye Hospital, Imperial College Healthcare Trust, London, UK
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38
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Progranulin deficiency causes the retinal ganglion cell loss during development. Sci Rep 2017; 7:1679. [PMID: 28490764 PMCID: PMC5431873 DOI: 10.1038/s41598-017-01933-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 04/03/2017] [Indexed: 01/22/2023] Open
Abstract
Astrocytes are glial cells that support and protect neurons in the central nervous systems including the retina. Retinal ganglion cells (RGCs) are in contact with the astrocytes and our earlier findings showed the reduction of the number of cells in the ganglion cell layer in adult progranulin deficient mice. In the present study, we focused on the time of activation of the astrocytes and the alterations in the number of RGCs in the retina and optic nerve in progranulin deficient mice. Our findings showed that the number of Brn3a-positive cells was reduced and the expression of glial fibrillary acidic protein (GFAP) was increased in progranulin deficient mice. The progranulin deficient mice had a high expression of GFAP on postnatal day 9 (P9) but not on postnatal day 1. These mice also had a decrease in the number of the Brn3a-positive cells on P9. Taken together, these findings indicate that the absence of progranulin can affect the survival of RGCs subsequent the activation of astrocytes during retinal development.
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Abstract
Glaucoma is characterized by a slow and progressive degeneration of the optic nerve, including retinal ganglion cell (RGC) axons in the optic nerve head (ONH), leading to visual impairment. Despite its high prevalence, the biological basis of glaucoma pathogenesis still is not yet fully understood, and the factors contributing to its progression are currently not well characterized. Intraocular pressure (IOP) is the only modifiable risk factor, and reduction of IOP is the standard treatment for glaucoma. However, lowering IOP itself is not always effective for preserving visual function in patients with primary open-angle glaucoma. The second messenger cyclic adenosine 3′,5′-monophosphate (cAMP) regulates numerous biological processes in the central nervous system including the retina and the optic nerve. Although recent studies revealed that cAMP generated by adenylyl cyclases (ACs) is important in regulating aqueous humor dynamics in ocular tissues, such as the ciliary body and trabecular meshwork, as well as cell death and growth in the retina and optic nerve, the functional role and significance of cAMP in glaucoma remain to be elucidated. In this review, we will discuss the functional role of cAMP in aqueous humor dynamics and IOP regulation, and review the current medications, which are related to the cAMP signaling pathway, for glaucoma treatment. Also, we will further focus on cAMP signaling in RGC growth and regeneration by soluble AC as well as ONH astrocytes by transmembrane ACs to understand its potential role in the pathogenesis of glaucoma neurodegeneration
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Affiliation(s)
- Myoung Sup Shim
- Hamilton Glaucoma Center and Department of Ophthalmology, Shiley Eye Institute, University of California San Diego, La Jolla, CA 92037, USA
| | - Keun-Young Kim
- Center for Research on Biological Systems, National Center for Microscopy and Imaging Research and Department of Neuroscience, University of California San Diego, La Jolla 92093, CA 92093, USA
| | - Won-Kyu Ju
- Hamilton Glaucoma Center and Department of Ophthalmology, Shiley Eye Institute, University of California San Diego, La Jolla, CA 92037, USA
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40
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Zhao L, Chen G, Li J, Fu Y, Mavlyutov TA, Yao A, Nickells RW, Gong S, Guo LW. An intraocular drug delivery system using targeted nanocarriers attenuates retinal ganglion cell degeneration. J Control Release 2017; 247:153-166. [PMID: 28063892 PMCID: PMC5323250 DOI: 10.1016/j.jconrel.2016.12.038] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 12/08/2016] [Accepted: 12/29/2016] [Indexed: 02/03/2023]
Abstract
Glaucoma is a common blinding disease characterized by loss of retinal ganglion cells (RGCs). To date, there is no clinically available treatment directly targeting RGCs. We aim to develop an RGC-targeted intraocular drug delivery system using unimolecular micelle nanoparticles (unimNPs) to prevent RGC loss. The unimNPs were formed by single/individual multi-arm star amphiphilic block copolymer poly(amidoamine)-polyvalerolactone-poly(ethylene glycol) (PAMAM-PVL-PEG). While the hydrophobic PAMAM-PVL core can encapsulate hydrophobic drugs, the hydrophilic PEG shell provides excellent water dispersity. We conjugated unimNPs with the cholera toxin B domain (CTB) for RGC-targeting and with Cy5.5 for unimNP-tracing. To exploit RGC-protective sigma-1 receptor (S1R), we loaded unimNPs with an endogenous S1R agonist dehydroepiandrosterone (DHEA) as an FDA-approved model drug. These unimNPs produced a steady DHEA release in vitro for over two months at pH7.4. We then co-injected (mice, intraocular) unimNPs with the glutamate analog N-methyl-d-aspartate (NMDA), which is excito-toxic and induces RGC death. The CTB-conjugated unimNPs (i.e., targeted NPs) accumulated at the RGC layer and effectively preserved RGCs at least for 14days, whereas the unimNPs without CTB (i.e., non-targeted NPs) showed neither accumulation at nor protection of NMDA-treated RGCs. Consistent with S1R functions, targeted NPs relative to non-targeted NPs showed markedly better inhibitory effects on apoptosis and oxidative/inflammatory stresses in the RGC layer. Hence, the DHEA-loaded, CTB-conjugated unimNPs represent an RGC/S1R dual-targeted nanoplatform that generates an efficacious template for further development of a sustainable intraocular drug delivery system to protect RGCs, which may be applicable to treatments directed at glaucomatous pathology.
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Affiliation(s)
- Lei Zhao
- Department of Surgery, 5151 Wisconsin Institute for Medical Research, University of Wisconsin-Madison, 1111 Highland Ave, Madison, WI 53705, USA
| | - Guojun Chen
- Department of Materials Science and Engineering, Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI 53715, USA
| | - Jun Li
- Department of Surgery, 5151 Wisconsin Institute for Medical Research, University of Wisconsin-Madison, 1111 Highland Ave, Madison, WI 53705, USA; Department of Ophthalmology, The First Hospital of China Medical University, Shenyang 110001, China.; Department of Ophthalmology, The 3rd People's Hospital of Dalian, Dalian 116033, China
| | - Yingmei Fu
- Department of Surgery, 5151 Wisconsin Institute for Medical Research, University of Wisconsin-Madison, 1111 Highland Ave, Madison, WI 53705, USA; Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, 600 Wanping Nan Road, Shanghai 200030, China
| | - Timur A Mavlyutov
- Department of Surgery, 5151 Wisconsin Institute for Medical Research, University of Wisconsin-Madison, 1111 Highland Ave, Madison, WI 53705, USA
| | - Annie Yao
- Department of Surgery, 5151 Wisconsin Institute for Medical Research, University of Wisconsin-Madison, 1111 Highland Ave, Madison, WI 53705, USA
| | - Robert W Nickells
- Department of Ophthalmology and Vision Sciences, University of Wisconsin-Madison, 1300 University Ave, Madison, WI 53706, USA; McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Shaoqin Gong
- Department of Materials Science and Engineering, Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI 53715, USA; Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI 53715, USA; McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI 53705, USA.
| | - Lian-Wang Guo
- Department of Surgery, 5151 Wisconsin Institute for Medical Research, University of Wisconsin-Madison, 1111 Highland Ave, Madison, WI 53705, USA; McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI 53705, USA.
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Lambert WS, Carlson BJ, Formichella CR, Sappington RM, Ahlem C, Calkins DJ. Oral Delivery of a Synthetic Sterol Reduces Axonopathy and Inflammation in a Rodent Model of Glaucoma. Front Neurosci 2017; 11:45. [PMID: 28223915 PMCID: PMC5293777 DOI: 10.3389/fnins.2017.00045] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 01/20/2017] [Indexed: 12/12/2022] Open
Abstract
Glaucoma is a group of optic neuropathies associated with aging and sensitivity to intraocular pressure (IOP). The disease is the leading cause of irreversible blindness worldwide. Early progression in glaucoma involves dysfunction of retinal ganglion cell (RGC) axons, which comprise the optic nerve. Deficits in anterograde transport along RGC axons to central visual structures precede outright degeneration, and preventing these deficits is efficacious at abating subsequent progression. HE3286 is a synthetic sterol derivative that has shown therapeutic promise in models of inflammatory disease and neurodegenerative disease. We examined the efficacy of HE3286 oral delivery in preventing loss of anterograde transport in an inducible model of glaucoma (microbead occlusion). Adult rats received HE3286 (20 or 100 mg/kg) or vehicle daily via oral gavage for 4 weeks. Microbead occlusion elevated IOP ~30% in all treatment groups, and elevation was not affected by HE3286 treatment. In the vehicle group, elevated IOP reduced anterograde axonal transport to the superior colliculus, the most distal site in the optic projection, by 43% (p = 0.003); HE3286 (100 mg/kg) prevented this reduction (p = 0.025). HE3286 increased brain-derived neurotrophic factor (BDNF) in the optic nerve head and retina, while decreasing inflammatory and pathogenic proteins associated with elevated IOP compared to vehicle treatment. Treatment with HE3286 also increased nuclear localization of the transcription factor NFκB in collicular and retinal neurons, but decreased NFκB in glial nuclei in the optic nerve head. Thus, HE3286 may have a neuroprotective influence in glaucoma, as well as other chronic neurodegenerations.
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Affiliation(s)
- Wendi S Lambert
- Vanderbilt University Medical Center, The Vanderbilt Eye Institute Nashville, TN, USA
| | - Brian J Carlson
- Vanderbilt University Medical Center, The Vanderbilt Eye Institute Nashville, TN, USA
| | - Cathryn R Formichella
- Vanderbilt University Medical Center, The Vanderbilt Eye Institute Nashville, TN, USA
| | - Rebecca M Sappington
- Vanderbilt University Medical Center, The Vanderbilt Eye Institute Nashville, TN, USA
| | | | - David J Calkins
- Vanderbilt University Medical Center, The Vanderbilt Eye Institute Nashville, TN, USA
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Calkins DJ, Pekny M, Cooper ML, Benowitz L. The challenge of regenerative therapies for the optic nerve in glaucoma. Exp Eye Res 2017; 157:28-33. [PMID: 28153739 DOI: 10.1016/j.exer.2017.01.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 01/12/2017] [Accepted: 01/26/2017] [Indexed: 11/15/2022]
Abstract
This review arose from a discussion of regenerative therapies to treat optic nerve degeneration in glaucoma at the 2015 Lasker/IRRF Initiative on Astrocytes and Glaucomatous Neurodegeneration. In addition to the authors, participants included Jonathan Crowston, Andrew Huberman, Elaine Johnson, Richard Lu, Hemai Phatnami, Rebecca Sappington, and Don Zack. Glaucoma is a neurodegenerative disease of the optic nerve, and is the leading cause of irreversible blindness worldwide. The disease progresses as sensitivity to intraocular pressure (IOP) is conveyed through the optic nerve head to distal retinal ganglion cell (RGC) projections. Because the nerve and retina are components of the central nervous system (CNS), their intrinsic regenerative capacity is limited. However, recent research in regenerative therapies has resulted in multiple breakthroughs that may unlock the optic nerve's regenerative potential. Increasing levels of Schwann-cell derived trophic factors and reducing potent cell-intrinsic suppressors of regeneration have resulted in axonal regeneration even beyond the optic chiasm. Despite this success, many challenges remain. RGC axons must be able to form new connections with their appropriate targets in central brain regions and these connections must be retinotopically correct. Furthermore, for new axons penetrating the optic projection, oligodendrocyte glia must provide myelination. Additionally, reactive gliosis and inflammation that increase the regenerative capacity must be outweigh pro-apoptotic processes to create an environment within which maximal regeneration can occur.
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Affiliation(s)
- David J Calkins
- Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, Nashville, TN 37205, USA.
| | - Milos Pekny
- Department of Clinical Neuroscience, Sahlgrenska Academy at University of Gothenburg, 41345, Göteborg, Sweden
| | - Melissa L Cooper
- Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, Nashville, TN 37205, USA
| | - Larry Benowitz
- Departments of Neurosurgery and Ophthalmology, Harvard Medical School, Boston, MA 02115, USA
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Non-amyloidogenic effects of α2 adrenergic agonists: implications for brimonidine-mediated neuroprotection. Cell Death Dis 2016; 7:e2514. [PMID: 27929541 PMCID: PMC5260990 DOI: 10.1038/cddis.2016.397] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Revised: 10/18/2016] [Accepted: 10/24/2016] [Indexed: 12/18/2022]
Abstract
The amyloid beta (Aβ) pathway is strongly implicated in neurodegenerative conditions such as Alzheimer's disease and more recently, glaucoma. Here, we identify the α2 adrenergic receptor agonists (α2ARA) used to lower intraocular pressure can prevent retinal ganglion cell (RGC) death via the non-amyloidogenic Aβ-pathway. Neuroprotective effects were confirmed in vivo and in vitro in different glaucoma-related models using α2ARAs brimonidine (BMD), clonidine (Clo) and dexmedetomidine. α2ARA treatment significantly reduced RGC apoptosis in experimental-glaucoma models by 97.7% and 92.8% (BMD, P<0.01) and 98% and 92.3% (Clo, P<0.01)) at 3 and 8 weeks, respectively. A reduction was seen in an experimental Aβ-induced neurotoxicity model (67% BMD and 88.6% Clo, both P<0.01, respectively), and in vitro, where α2ARAs significantly (P<0.05) prevented cell death, under both hypoxic (CoCl2) and stress (UV) conditions. In experimental-glaucoma, BMD induced ninefold and 25-fold and 36-fold and fourfold reductions in Aβ and amyloid precursor protein (APP) levels at 3 and 8 weeks, respectively, in the RGC layer, with similar results with Clo, and in vitro with all three α2ARAs. BMD significantly increased soluble APPα (sAPPα) levels at 3 and 8 weeks (2.1 and 1.6-fold) in vivo and in vitro with the CoCl2 and UV-light insults. Furthermore, treatment of UV-insulted cells with an sAPPα antibody significantly reduced cell viability compared with BMD-treated control (52%), co-treatment (33%) and untreated control (27%). Finally, we show that α2ARAs modulate levels of laminin and MMP-9 in RGCs, potentially linked to changes in Aβ through APP processing. Together, these results provide new evidence that α2ARAs are neuroprotective through their effects on the Aβ pathway and sAPPα, which to our knowledge, is the first description. Studies have identified the need for α-secretase activators and sAPPα-mimetics in neurodegeneration; α2ARAs, already clinically available, present a promising therapy, with applications not only to reducing RGC death in glaucoma but also other neurodegenerative processes involving Aβ.
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Shinno K, Kurokawa K, Kozai S, Kawamura A, Inada K, Tokushige H. The Relationship of Brimonidine Concentration in Vitreous Body to the Free Concentration in Retina/Choroid Following Topical Administration in Pigmented Rabbits. Curr Eye Res 2016; 42:748-753. [DOI: 10.1080/02713683.2016.1238941] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
| | | | - Seiko Kozai
- Senju Pharmaceutical Co., Ltd., Osaka, Japan
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Manickavasagam D, Wehrung D, Chamsaz EA, Sanders M, Bouhenni R, Crish SD, Joy A, Oyewumi MO. Assessment of alkoxylphenacyl-based polycarbonates as a potential platform for controlled delivery of a model anti-glaucoma drug. Eur J Pharm Biopharm 2016; 107:56-66. [DOI: 10.1016/j.ejpb.2016.06.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 06/06/2016] [Accepted: 06/15/2016] [Indexed: 01/22/2023]
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Central visual pathways in glaucoma: evidence for distal mechanisms of neuronal self-repair. J Neuroophthalmol 2016; 35 Suppl 1:S29-37. [PMID: 26274834 DOI: 10.1097/wno.0000000000000291] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
As in other age-related neurodegenerative diseases, progression of neurodegeneration in glaucoma involves early axonopathy. In glaucoma, this is marked by degradation of active transport along retinal ganglion cell (RGC) axons projecting from the retina to the brain. In experimental systems, transport degradation occurs first in the most distal site in the RGC projection, the superior colliculus (SC) of the midbrain. Even as degradation progresses from one retinotopic sector to the next, important structures in the affected sectors persist, including synapses from RGC axon terminals onto SC neurons. This structural persistence is accompanied by focally increased brain-derived neurotrophic factor in hypertrophic SC astrocyte glia and defines a therapeutic window of opportunity. Thus, central brain structures in glaucoma may respond to disease-relevant stress by induction of mechanisms useful for maintaining retinal signals.
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47
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Doozandeh A, Yazdani S. Neuroprotection in Glaucoma. J Ophthalmic Vis Res 2016; 11:209-20. [PMID: 27413504 PMCID: PMC4926571 DOI: 10.4103/2008-322x.183923] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2015] [Accepted: 08/03/2015] [Indexed: 11/04/2022] Open
Abstract
Glaucoma is a degenerative optic neuropathy characterized by retinal ganglion cell (RGC) loss and visual field defects. It is known that in some glaucoma patients, death of RGCs continues despite intraocular pressure (IOP) reduction. Neuroprotection in the field of glaucoma is defined as any treatment, independent of IOP reduction, which prevents RGC death. Glutamate antagonists, ginkgo biloba extract, neurotrophic factors, antioxidants, calcium channel blockers, brimonidine, glaucoma medications with blood regulatory effect and nitric oxide synthase inhibitors are among compounds with possible neuroprotective activity in preclinical studies. A few agents (such as brimonidine or memantine) with neuroprotective effects in experimental studies have advanced to clinical trials; however the results of clinical trials for these agents have not been conclusive. Nevertheless, lack of compelling clinical evidence has not prevented the off-label use of some of these compounds in glaucoma practice. Stem cell transplantation has been reported to halt experimental neurodegenerative disease processes in the absence of cell replacement. It has been hypothesized that transplantation of some types of stem cells activates multiple neuroprotective pathways via secretion of various factors. The advantage of this approach is a prolonged and targeted effect. Important concerns in this field include the secretion of unwanted harmful mediators, graft survival issues and tumorigenesis. Neuroprotection in glaucoma, pharmacologically or by stem cell transplantation, is an interesting subject waiting for broad and multidisciplinary collaborative studies to better clarify its role in clinical practice.
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Affiliation(s)
- Azadeh Doozandeh
- Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Shahin Yazdani
- Ocular Tissue Engineering Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Sappington RM, Sidorova T, Ward NJ, Chakravarthy R, Ho KW, Calkins DJ. Activation of transient receptor potential vanilloid-1 (TRPV1) influences how retinal ganglion cell neurons respond to pressure-related stress. Channels (Austin) 2016; 9:102-13. [PMID: 25713995 DOI: 10.1080/19336950.2015.1009272] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Our recent studies implicate the transient receptor potential vanilloid-1 (TRPV1) channel as a mediator of retinal ganglion cell (RGC) function and survival. With elevated pressure in the eye, TRPV1 increases in RGCs, supporting enhanced excitability, while Trpv1 -/- accelerates RGC degeneration in mice. Here we find TRPV1 localized in monkey and human RGCs, similar to rodents. Expression increases in RGCs exposed to acute changes in pressure. In retinal explants, contrary to our animal studies, both Trpv1 -/- and pharmacological antagonism of the channel prevented pressure-induced RGC apoptosis, as did chelation of extracellular Ca(2+). Finally, while TRPV1 and TRPV4 co-localize in some RGC bodies and form a protein complex in the retina, expression of their mRNA is inversely related with increasing ocular pressure. We propose that TRPV1 activation by pressure-related insult in the eye initiates changes in expression that contribute to a Ca(2+)-dependent adaptive response to maintain excitatory signaling in RGCs.
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Affiliation(s)
- Rebecca M Sappington
- a The Vanderbilt Eye Institute and Vanderbilt Brain Institute ; Vanderbilt University School of Medicine ; Nashville , TN USA
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Bond WS, Hines-Beard J, GoldenMerry YPL, Davis M, Farooque A, Sappington RM, Calkins DJ, Rex TS. Virus-mediated EpoR76E Therapy Slows Optic Nerve Axonopathy in Experimental Glaucoma. Mol Ther 2015; 24:230-239. [PMID: 26502777 DOI: 10.1038/mt.2015.198] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 10/13/2015] [Indexed: 12/19/2022] Open
Abstract
Glaucoma, a common cause of blindness, is currently treated by intraocular pressure (IOP)-lowering interventions. However, this approach is insufficient to completely prevent vision loss. Here, we evaluate an IOP-independent gene therapy strategy using a modified erythropoietin, EPO-R76E, which has reduced erythropoietic function. We used two models of glaucoma, the murine microbead occlusion model and the DBA/2J mouse. Systemic recombinant adeno-associated virus-mediated gene delivery of EpoR76E (rAAV.EpoR76E) was performed concurrent with elevation of IOP. Axon structure and active anterograde transport were preserved in both models. Vision, as determined by the flash visual evoked potential, was preserved in the DBA/2J. These results show that systemic EpoR76E gene therapy protects retinal ganglion cells from glaucomatous degeneration in two different models. This suggests that EPO targets a component of the neurodegenerative pathway that is common to both models. The efficacy of rAAV.EpoR76E delivered at onset of IOP elevation supports clinical relevance of this treatment.
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Affiliation(s)
- Wesley S Bond
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, Tennessee, USA; Vanderbilt Brain Institute, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Jessica Hines-Beard
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, Tennessee, USA; Vanderbilt Brain Institute, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - YPaul L GoldenMerry
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Mara Davis
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Alma Farooque
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Rebecca M Sappington
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, Tennessee, USA; Vanderbilt Brain Institute, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - David J Calkins
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, Tennessee, USA; Vanderbilt Brain Institute, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Tonia S Rex
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, Tennessee, USA; Vanderbilt Brain Institute, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
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Vidal-Sanz M, Valiente-Soriano FJ, Ortín-Martínez A, Nadal-Nicolás FM, Jiménez-López M, Salinas-Navarro M, Alarcón-Martínez L, García-Ayuso D, Avilés-Trigueros M, Agudo-Barriuso M, Villegas-Pérez MP. Retinal neurodegeneration in experimental glaucoma. PROGRESS IN BRAIN RESEARCH 2015; 220:1-35. [PMID: 26497783 DOI: 10.1016/bs.pbr.2015.04.008] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In rats and mice, limbar tissues of the left eye were laser-photocoagulated (LP) and ocular hypertension (OHT) effects were investigated 1 week to 6 months later. To investigate the innermost layers, retinas were examined in wholemounts using tracing from the superior colliculi to identify retinal ganglion cells (RGCs) with intact retrograde axonal transport, melanopsin immunodetection to identify intrinsically photosensitive RGCs (m(+)RGC), Brn3a immunodetection to identify most RGCs but not m(+)RGCs, RECA1 immunodetection to examine the inner retinal vessels, and DAPI staining to detect all nuclei in the GC layer. The outer retinal layers (ORLs) were examined in cross sections analyzed morphometrically or in wholemounts to study S- and L-cones. Innervation of the superior colliculi was examined 10 days to 14 weeks after LP with orthogradely transported cholera toxin subunit B. By 2 weeks, OHT resulted in pie-shaped sectors devoid of FG(+)RGCs or Brn3a(+)RGCs but with large numbers of DAPI(+)nuclei. Brn3a(+)RGCs were significantly greater than FG(+)RGCs, indicating the survival of large numbers of RGCs with their axonal transport impaired. The inner retinal vasculature showed no abnormalities that could account for the sectorial loss of RGCs. m(+)RGCs decreased to approximately 50-51% in a diffuse loss across the retina. Cross sections showed focal areas of degeneration in the ORLs. RGC loss at 1m diminished to 20-25% and did not progress further with time, whereas the S- and L-cone populations diminished progressively up to 6m. The retinotectal projection was reduced by 10 days and did not progress further. LP-induced OHT results in retrograde degeneration of RGCs and m(+)RGCs, severe damage to the ORL, and loss of retinotectal terminals.
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Affiliation(s)
- Manuel Vidal-Sanz
- Departamento de Oftalmología, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain.
| | - Francisco J Valiente-Soriano
- Departamento de Oftalmología, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
| | - Arturo Ortín-Martínez
- Departamento de Oftalmología, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
| | - Francisco M Nadal-Nicolás
- Departamento de Oftalmología, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
| | - Manuel Jiménez-López
- Departamento de Oftalmología, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
| | - Manuel Salinas-Navarro
- Departamento de Oftalmología, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
| | - Luis Alarcón-Martínez
- Departamento de Oftalmología, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
| | - Diego García-Ayuso
- Departamento de Oftalmología, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
| | - Marcelino Avilés-Trigueros
- Departamento de Oftalmología, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
| | - Marta Agudo-Barriuso
- Departamento de Oftalmología, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
| | - Maria P Villegas-Pérez
- Departamento de Oftalmología, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
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