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Willms JO, Mitchell K, Shashtri M, Sundin O, Liu X, Panthagani P, Tran P, Navarro S, Sniegowski C, Shaik AA, Chaudhury T, Reid TW, Bergeson SE. Minocycline and Diacetyl Minocycline Eye Drops Reduce Ocular Neovascularization in Mice. Transl Vis Sci Technol 2023; 12:10. [PMID: 38064336 PMCID: PMC10709801 DOI: 10.1167/tvst.12.12.10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 09/24/2023] [Indexed: 12/18/2023] Open
Abstract
Purpose To evaluate the efficacy of minocycline and a novel, modified minocycline analogue that lacks antimicrobial action, diacetyl minocycline (DAM), on choroidal neovascularization (CNV) in mice of both sexes. Methods CNV was induced via laser injury in female and male C57BL/6J mice. Minocycline, DAM, or saline was administered via topical eye drops twice a day for 2 weeks starting the day after laser injury. CNV volume was measured using immunohistochemistry labeling and confocal microscopy. Results Minocycline reduced lesion volume by 79% (P ≤ 0.0004) in female and male mice. DAM reduced lesion volume by 73% (P ≤ 0.001) in female and male mice. There was no significant difference in lesion volume between minocycline and DAM treatment groups or between female and male mice. Conclusions Both minocycline and DAM eye drops significantly reduced laser-induced CNV lesion volume in female and male mice. While oral tetracyclines have been shown to mitigate pathologic neovascularization in both preclinical studies and clinical trials, the present data are the first to suggest that tetracycline derivatives may be effective to reduce pathologic CNV when administered via topical eye drops. However, the action is unrelated to antimicrobial action. Targeted delivery of these medications via eye drops may reduce the potential for systemic side effects. Translational Relevance Topical administration of minocycline and/or DAM via eye drops may represent a novel therapeutic strategy for disorders involving pathologic CNV.
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Affiliation(s)
- Joshua O. Willms
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Kelly Mitchell
- Department of Ophthalmology and Visual Sciences, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | | | - Olof Sundin
- Department of Ophthalmology and Visual Sciences, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Xiaobo Liu
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Praneetha Panthagani
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Phat Tran
- Department of Ophthalmology and Visual Sciences, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Stephany Navarro
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Colton Sniegowski
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Abdul A. Shaik
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Tristin Chaudhury
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Ted W. Reid
- Department of Ophthalmology and Visual Sciences, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Susan E. Bergeson
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX, USA
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Muns SM, Villegas VM, Flynn HW, Schwartz SG. Update on current pharmacologic therapies for diabetic retinopathy. Expert Opin Pharmacother 2023; 24:1577-1593. [PMID: 37431888 DOI: 10.1080/14656566.2023.2230139] [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: 04/04/2023] [Revised: 06/16/2023] [Accepted: 06/23/2023] [Indexed: 07/12/2023]
Abstract
INTRODUCTION Diabetic retinopathy is a major cause of visual loss worldwide. The most important clinical findings include diabetic macular edema (DME) and proliferative diabetic retinopathy (PDR). AREAS COVERED PubMed was used for our literature review. Articles from 1995 to 2023 were included. Pharmacologic treatment of diabetic retinopathy generally involves the use of intravitreal anti-vascular endothelial growth factor (VEGF) therapy for DME and PDR. Corticosteroids remain important second-line therapies for patients with DME. Most emerging therapies focus on newly identified inflammatory mediators and biochemical signaling pathways involved in disease pathogenesis. EXPERT OPINION Emerging anti-VEGF modalities, integrin antagonists, and anti-inflammatory agents have the potential to improve outcomes with reduced treatment burdens.
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Affiliation(s)
- Sofía M Muns
- Department of Ophthalmology, University of Puerto Rico, San Juan, Puerto Rico
| | - Victor M Villegas
- Department of Ophthalmology, University of Puerto Rico, San Juan, Puerto Rico
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Harry W Flynn
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Stephen G Schwartz
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
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Huang K, Liu X, Lv Z, Zhang D, Zhou Y, Lin Z, Guo J. MMP9-Responsive Graphene Oxide Quantum Dot-Based Nano-in-Micro Drug Delivery System for Combinatorial Therapy of Choroidal Neovascularization. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2207335. [PMID: 36871144 DOI: 10.1002/smll.202207335] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 01/29/2023] [Indexed: 06/18/2023]
Abstract
Age-related macular degeneration (AMD), especially wet AMD with choroidal neovascularization (CNV), commonly causes blindness in older patients and disruption of the choroid followed by second-wave injuries, including chronic inflammation, oxidative stress, and excessive matrix metalloproteinase 9 (MMP9) expression. Increased macrophage infiltrate in parallel with microglial activation and MMP9 overexpression on CNV lesions is shown to contribute to the inflammatory process and then enhance pathological ocular angiogenesis. Graphene oxide quantum dots (GOQDs), as natural antioxidants, exert anti-inflammatory effects and minocycline is a specific macrophage/microglial inhibitor that can suppress both macrophage/microglial activation and MMP9 activity. Herein, an MMP9-responsive GOQD-based minocycline-loaded nano-in-micro drug delivery system (C18PGM) is developed by chemically bonding GOQDs to an octadecyl-modified peptide sequence (C18-GVFHQTVS, C18P) that can be specifically cleaved by MMP9. Using a laser-induced CNV mouse model, the prepared C18PGM shows significant MMP9 inhibitory activity and anti-inflammatory action followed by antiangiogenic effects. Moreover, C18PGM combined with antivascular endothelial growth factor antibody bevacizumab markedly increases the antiangiogenesis effect by interfering with the "inflammation-MMP9-angiogenesis" cascade. The prepared C18PGM shows a good safety profile and no obvious ophthalmic or systemic side effects. The results taken together suggest that C18PGM is an effective and novel strategy for combinatorial therapy of CNV.
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Affiliation(s)
- Keke Huang
- Institute of Advanced Materials for Nano-Bio Applications, School of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, 325027, P. R. China
| | - Xin Liu
- Institute of Advanced Materials for Nano-Bio Applications, School of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, 325027, P. R. China
| | - Ziru Lv
- Institute of Advanced Materials for Nano-Bio Applications, School of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, 325027, P. R. China
| | - Di Zhang
- Institute of Advanced Materials for Nano-Bio Applications, School of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, 325027, P. R. China
| | - Yuling Zhou
- Department of ophthalmology, Huangshi Central Hospital, Affiliated Hospital of Hubei Polytechnic University, Huangshi, Hubei, 435000, P. R. China
| | - Zhiqing Lin
- Institute of Advanced Materials for Nano-Bio Applications, School of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, 325027, P. R. China
| | - Juan Guo
- Department of Ophthalmology, The Third People's Hospital of Chengdu, The Affiliated Hospital of Southwest Jiaotong University, Chengdu, Sichuan, 610031, P. R. China
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Dave AD, Chen KG, Chiang TTK, Singaravelu J, Alvarez JA, Wong WT, Cukras CA. Oral minocycline for the treatment of retinitis pigmentosa-associated cystoid macular edema: results of a phase I/II clinical trial. Graefes Arch Clin Exp Ophthalmol 2023; 261:2209-2220. [PMID: 36882562 DOI: 10.1007/s00417-023-05986-6] [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: 08/16/2022] [Revised: 01/13/2023] [Accepted: 01/27/2023] [Indexed: 03/09/2023] Open
Abstract
PURPOSE The etiology of retinitis pigmentosa (RP)-associated cystoid macular edema (CME) has been related to retinal neuroinflammation and microglial activation. Minocycline, a drug FDA-approved for anti-microbial indications, also inhibits microglial activation and expression of inflammatory mediators. This study investigates the safety and efficacy of oral minocycline as primary treatment for RP-associated CME. METHODS A single-center, prospective, open-label phase I/II clinical trial enrolled five participants with RP-associated CME. Participants had lead-in assessments prior to the initiation of oral minocycline 100 mg twice daily for 12 months. Main outcome variables included changes in best-corrected visual acuity (BCVA) and retinal central subfield thickness (CST) measured using spectral domain optical coherence tomography relative to mean of pre-treatment measurements. RESULTS The study drug was well tolerated and not associated with any severe adverse events. No significant changes in mean BCVA from study baseline were noted in either the study eye (+ 0.7 ± 4.1 letters at 6 months, - 1.1 ± 1.7 letters at 12 months) or the qualifying fellow eye (- 0.3 ± 3.4 letters at 6 months, - 0.3 ± 4.6 letters at 12 months) (p > 0.05 for all comparisons). Mean percentage changes in CST from baseline however decreased progressively with treatment (decreases at 6 and 12 months: study eyes 3.9 and 9.8%; qualifying fellow eyes 1.4 and 7.7%). Considering all eyes (n = 10), mean percentage CST decrease at 6 and 12 months was 2.7 ± 9.5% (p = 0.39) and 8.7 ± 9.5% (p = 0.02) respectively. CONCLUSION Oral minocycline administration over 12 months was associated with no significant changes in mean BCVA and a small but progressive decrease in mean CST. TRIAL REGISTRATION NCT02140164 (05/2014).
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Affiliation(s)
- Amisha D Dave
- National Eye Institute, NIH, Bethesda, MD, 20892, USA
| | | | | | | | | | - Wai T Wong
- National Eye Institute, NIH, Bethesda, MD, 20892, USA
| | - Catherine A Cukras
- Unit On Clinical Investigation of Retinal Disease, Division of Epidemiology and Clinical Research, National Eye Institute, National Institute of Health, Bethesda, MD, 20892, USA.
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Padovani-Claudio DA, Ramos CJ, Capozzi ME, Penn JS. Elucidating glial responses to products of diabetes-associated systemic dyshomeostasis. Prog Retin Eye Res 2023; 94:101151. [PMID: 37028118 PMCID: PMC10683564 DOI: 10.1016/j.preteyeres.2022.101151] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 11/21/2022] [Accepted: 11/22/2022] [Indexed: 04/08/2023]
Abstract
Diabetic retinopathy (DR) is a leading cause of blindness in working age adults. DR has non-proliferative stages, characterized in part by retinal neuroinflammation and ischemia, and proliferative stages, characterized by retinal angiogenesis. Several systemic factors, including poor glycemic control, hypertension, and hyperlipidemia, increase the risk of DR progression to vision-threatening stages. Identification of cellular or molecular targets in early DR events could allow more prompt interventions pre-empting DR progression to vision-threatening stages. Glia mediate homeostasis and repair. They contribute to immune surveillance and defense, cytokine and growth factor production and secretion, ion and neurotransmitter balance, neuroprotection, and, potentially, regeneration. Therefore, it is likely that glia orchestrate events throughout the development and progression of retinopathy. Understanding glial responses to products of diabetes-associated systemic dyshomeostasis may reveal novel insights into the pathophysiology of DR and guide the development of novel therapies for this potentially blinding condition. In this article, first, we review normal glial functions and their putative roles in the development of DR. We then describe glial transcriptome alterations in response to systemic circulating factors that are upregulated in patients with diabetes and diabetes-related comorbidities; namely glucose in hyperglycemia, angiotensin II in hypertension, and the free fatty acid palmitic acid in hyperlipidemia. Finally, we discuss potential benefits and challenges associated with studying glia as targets of DR therapeutic interventions. In vitro stimulation of glia with glucose, angiotensin II and palmitic acid suggests that: 1) astrocytes may be more responsive than other glia to these products of systemic dyshomeostasis; 2) the effects of hyperglycemia on glia are likely to be largely osmotic; 3) fatty acid accumulation may compound DR pathophysiology by promoting predominantly proinflammatory and proangiogenic transcriptional alterations of macro and microglia; and 4) cell-targeted therapies may offer safer and more effective avenues for DR treatment as they may circumvent the complication of pleiotropism in retinal cell responses. Although several molecules previously implicated in DR pathophysiology are validated in this review, some less explored molecules emerge as potential therapeutic targets. Whereas much is known regarding glial cell activation, future studies characterizing the role of glia in DR and how their activation is regulated and sustained (independently or as part of retinal cell networks) may help elucidate mechanisms of DR pathogenesis and identify novel drug targets for this blinding disease.
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Affiliation(s)
- Dolly Ann Padovani-Claudio
- Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, B3321A Medical Center North, 1161 21st Avenue South, Nashville, TN, 37232-0011, USA.
| | - Carla J Ramos
- Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, AA1324 Medical Center North, 1161 21st Avenue South, Nashville, TN, 37232-0011, USA.
| | - Megan E Capozzi
- Duke Molecular Physiology Institute, Duke University School of Medicine, 300 North Duke Street, Durham, NC, 27701, USA.
| | - John S Penn
- Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, B3307 Medical Center North, 1161 21st Avenue South, Nashville, TN, 37232-0011, USA.
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Li X, Zhang W, Ye Z, Pei S, Zheng D, Zhu L. Safety evaluation and pharmacodynamics of minocycline hydrochloride eye drops. Mol Vis 2022; 28:460-479. [PMID: 36605830 PMCID: PMC9784630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 12/19/2022] [Indexed: 01/07/2023] Open
Abstract
PURPOSE This study evaluated the safe dosage of minocycline hydrochloride (Mino) eye drops and investigated the potential for the prevention or reduction of retinal damage in a diabetic rat model. METHODS Various concentrations of Mino were applied to human corneal epithelial cells (HCECs) to determine the half maximal inhibitory concentration (IC50). The safety of Mino eye drops was evaluated on Sprague-Dawley (SD) rat eyes by slit-lamp examination, electroretinography (ERG), histology, and TUNEL assay. Eye drops (1 mg/ml) were applied to the streptozotocin-induced diabetic SD rats. Clinical observations, ERG analyses, and optical coherence tomography analyses were performed monthly for five months. Eyes were then analyzed via histology, blood-retinal barrier function assay, and retinal vascular staining. RESULTS Cytotoxicity analysis using HCECs revealed that the IC50 was 250 µg/ml. Safety analyses in healthy SD rats showed that Mino eye drops did not demonstrate any ocular toxicity. Pharmacodynamics analysis showed that retinal thickness at three months was greater in the Mino group than in the non treated (NT) group. The peak times and amplitudes of each program were better in the Mino group than in the NT group at each time point by ERG analyses. Histology examinations showed a thinner ganglion cell layer, fewer ganglion cells, and more dilated blood vessels in the NT group than in the Mino group. CONCLUSION Mino eye drops at 1 mg/ml were safe when used in SD rats. Mino eye drops can protect the retina from the development or progression of diabetic retinopathy.
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Affiliation(s)
- Xiaoli Li
- Henan Eye Institute, Henan Eye Hospital, Henan Provincial People's Hospital, Henan University People's Hospital, Zhengzhou, China
| | - Wenhua Zhang
- Henan Eye Institute, Henan Eye Hospital, Henan Provincial People's Hospital, Henan University People's Hospital, Zhengzhou, China
| | - Zhiqiang Ye
- Institute of Advanced Materials for Nano-Bio Applications, School of Ophthalmology & Optometry, Wenzhou Medical University, Wenzhou, China
| | - Shuaili Pei
- Institute of Advanced Materials for Nano-Bio Applications, School of Ophthalmology & Optometry, Wenzhou Medical University, Wenzhou, China
| | - Dongliang Zheng
- Institute of Advanced Materials for Nano-Bio Applications, School of Ophthalmology & Optometry, Wenzhou Medical University, Wenzhou, China
| | - Lin Zhu
- Institute of Advanced Materials for Nano-Bio Applications, School of Ophthalmology & Optometry, Wenzhou Medical University, Wenzhou, China
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Sinclair SH, Miller E, Talekar KS, Schwartz SS. Diabetes mellitus associated neurovascular lesions in the retina and brain: A review. FRONTIERS IN OPHTHALMOLOGY 2022; 2:1012804. [PMID: 38983558 PMCID: PMC11182219 DOI: 10.3389/fopht.2022.1012804] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 10/14/2022] [Indexed: 07/11/2024]
Abstract
Diabetes mellitus (DM) is now recognized as a system-wide, autoimmune, inflammatory, microvascular disorder, which, in the retina and brain results in severe multifocal injury now recognized as a leading cause, world-wide, of progressive vision loss and dementia. To address this problem, resulting primarily from variations in glycemia in the prediabetic and overt diabetic states, it must be realized that, although some of the injury processes associated with diabetes may be system wide, there are varying responses, effector, and repair mechanisms that differ from organ to organ or within varying cell structures. Specifically, within the retina, and similarly within the brain cortex, lesions occur of the "neurovascular unit", comprised of focal microvascular occlusions, inflammatory endothelial and pericyte injury, with small vessel leakage resulting in injury to astrocytes, Müller cells, and microglia, all of which occur with progressive neuronal apoptosis. Such lesions are now recognized to occur before the first microaneurysms are visible to imaging by fundus cameras or before they result in detectable symptoms or signs recognizable to the patient or clinician. Treatments, therefore, which currently are not initiated within the retina until edema develops or there is progression of vascular lesions that define the current staging of retinopathy, and in the brain only after severe signs of cognitive failure. Treatments, therefore are applied relatively late with some reduction in progressive cellular injury but with resultant minimal vision or cognitive improvement. This review article will summarize the multiple inflammatory and remediation processes currently understood to occur in patients with diabetes as well as pre-diabetes and summarize as well the current limitations of methods for assessing the structural and functional alterations within the retina and brain. The goal is to attempt to define future screening, monitoring, and treatment directions that hopefully will prevent progressive injury as well as enable improved repair and attendant function.
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Affiliation(s)
- Stephen H Sinclair
- Pennsylvania College of Optometry, Salus University, Philadelphia, PA, United States
| | - Elan Miller
- Division of Vascular Neurology, Vickie & Jack Farber Institute for Institute for Neuroscience, Sidney Kimmel Medical College (SKMC) Thomas Jefferson University, Philadelphia, PA, United States
| | - Kiran S Talekar
- Department of Radiology, Section of Neuroradiology and ENT Radiology, Clinical Functional Magnetic Resonance Imaging and Diffusion Tensor Imaging at Thomas Jefferson University Hospital and The Jefferson Integrated Magnetic Resonance Imaging Center (JIMRIC) Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA, United States
| | - Stanley S Schwartz
- Department of Endocrinology and Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Main Line Health System, Philadelphia, PA, United States
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Diabetic Macular Edema: Current Understanding, Molecular Mechanisms and Therapeutic Implications. Cells 2022; 11:cells11213362. [PMID: 36359761 PMCID: PMC9655436 DOI: 10.3390/cells11213362] [Citation(s) in RCA: 47] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 10/19/2022] [Accepted: 10/20/2022] [Indexed: 11/24/2022] Open
Abstract
Diabetic retinopathy (DR), with increasing incidence, is the major cause of vision loss and blindness worldwide in working-age adults. Diabetic macular edema (DME) remains the main cause of vision impairment in diabetic patients, with its pathogenesis still not completely elucidated. Vascular endothelial growth factor (VEGF) plays a pivotal role in the pathogenesis of DR and DME. Currently, intravitreal injection of anti-VEGF agents remains as the first-line therapy in DME treatment due to the superior anatomic and functional outcomes. However, some patients do not respond satisfactorily to anti-VEGF injections. More than 30% patients still exist with persistent DME even after regular intravitreal injection for at least 4 injections within 24 weeks, suggesting other pathogenic factors, beyond VEGF, might contribute to the pathogenesis of DME. Recent advances showed nearly all the retinal cells are involved in DR and DME, including breakdown of blood-retinal barrier (BRB), drainage dysfunction of Müller glia and retinal pigment epithelium (RPE), involvement of inflammation, oxidative stress, and neurodegeneration, all complicating the pathogenesis of DME. The profound understanding of the changes in proteomics and metabolomics helps improve the elucidation of the pathogenesis of DR and DME and leads to the identification of novel targets, biomarkers and potential therapeutic strategies for DME treatment. The present review aimed to summarize the current understanding of DME, the involved molecular mechanisms, and the changes in proteomics and metabolomics, thus to propose the potential therapeutic recommendations for personalized treatment of DME.
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Takkar B, Sheemar A, Jayasudha R, Soni D, Narayanan R, Venkatesh P, Shivaji S, Das T. Unconventional avenues to decelerated diabetic retinopathy. Surv Ophthalmol 2022; 67:1574-1592. [PMID: 35803389 DOI: 10.1016/j.survophthal.2022.06.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 06/28/2022] [Accepted: 06/30/2022] [Indexed: 02/07/2023]
Abstract
Diabetic retinopathy (DR) is an important microvascular complication of diabetes mellitus (DM), causing significant visual impairment worldwide. Current gold standards for retarding the progress of DR include blood sugar control and regular fundus screening. Despite these measures, the incidence and prevalence of DR and vision-threatening DR remain high. Given its slowly progressive course and long latent period, opportunities to contain or slow DR before it threatens vision must be explored. This narrative review assesses the recently described unconventional strategies to retard DR progression. These include gut-ocular flow, gene therapy, mitochondrial dysfunction-oxidative stress, stem cell therapeutics, neurodegeneration, anti-inflammatory treatments, lifestyle modification, and usage of phytochemicals. These therapies impact DR directly, while some of them also influence DM control. Most of these strategies are currently in the preclinical stage, and clinical evidence remains low. Nevertheless, our review suggests that these approaches have the potential for human use to prevent the progression of DR.
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Affiliation(s)
- Brijesh Takkar
- Srimati Kanuri Santhamma Centre for Vitreoretinal Diseases, L V Prasad Eye Institute, Hyderabad, India; Indian Health Outcomes, Public Health, and Economics Research (IHOPE) Centre, L V Prasad Eye Institute, Hyderabad, India.
| | - Abhishek Sheemar
- Department of Ophthalmology, All India Institute of Medical Sciences, Jodhpur, India
| | | | - Deepak Soni
- Department of Ophthalmology, All India Institute of Medical Sciences, Bhopal, India
| | - Raja Narayanan
- Srimati Kanuri Santhamma Centre for Vitreoretinal Diseases, L V Prasad Eye Institute, Hyderabad, India; Indian Health Outcomes, Public Health, and Economics Research (IHOPE) Centre, L V Prasad Eye Institute, Hyderabad, India
| | - Pradeep Venkatesh
- Dr. RP Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Sisinthy Shivaji
- Prof. Brien Holden Eye Research Centre, L V Prasad Eye Institute, Hyderabad, India
| | - Taraprasad Das
- Srimati Kanuri Santhamma Centre for Vitreoretinal Diseases, L V Prasad Eye Institute, Hyderabad, India
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Fan W, Huang W, Chen J, Li N, Mao L, Hou S. Retinal microglia: Functions and diseases. Immunology 2022; 166:268-286. [PMID: 35403700 DOI: 10.1111/imm.13479] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 01/26/2022] [Accepted: 02/22/2022] [Indexed: 11/29/2022] Open
Affiliation(s)
- Wei Fan
- The First Affiliated Hospital of Chongqing Medical University Chongqing China
- Chongqing Key Laboratory of Ophthalmology Chongqing China
- Chongqing Eye Institute Chongqing China
- Chongqing Branch of National Clinical Research Center for Ocular Diseases Chongqing China
| | - Weidi Huang
- The First Affiliated Hospital of Chongqing Medical University Chongqing China
- Department of Ophthalmology, Second Xiangya Hospital Central South University Changsha Hunan China
| | - Jiayi Chen
- The First Affiliated Hospital of Chongqing Medical University Chongqing China
| | - Na Li
- College of Basic Medicine Chongqing Medical University Chongqing China
| | - Liming Mao
- Department of Immunology School of Medicine, Nantong University, 19 Qixiu Road Nantong Jiangsu China
| | - Shengping Hou
- The First Affiliated Hospital of Chongqing Medical University Chongqing China
- Chongqing Key Laboratory of Ophthalmology Chongqing China
- Chongqing Eye Institute Chongqing China
- Chongqing Branch of National Clinical Research Center for Ocular Diseases Chongqing China
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11
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Lin Y, Ren X, Chen D. Steroid Treatment in Macular Edema: A Bibliometric Study and Visualization Analysis. Front Pharmacol 2022; 13:824790. [PMID: 35273502 PMCID: PMC8902303 DOI: 10.3389/fphar.2022.824790] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 01/17/2022] [Indexed: 02/05/2023] Open
Abstract
The use of steroids to treat macular edema (ME) is a research hotspot in ophthalmology. We utilized CiteSpace and VOSviewer software to evaluate the Web of Science Core Collection publications and to build visualizing maps to describe the research progress in this topic. There were 3,252 publications for three decades during 1988–2021. The number of studies was low during the first 14 years but has risen consistently in the following two decades. The average publications per year were only 4.8 during 1988–2002, which jumped to 113 per year during 2003–2012, and 227 per year during 2013–2021. These publications came from 83 countries/regions, with the United States, Germany, and Italy leading positions. Most studies were published in Investigative Ophthalmology Visual Science, and Ophthalmology was the most cited journal. We found 9,993 authors, with Bandello F having the most publications and Jonas JB being the most frequently co-cited. According to our research, the most popular keyword is triamcinolone acetonide (TA). Macular edema, diabetic macular edema (DME), retinal vein occlusion (RVO), dexamethasone (DEX), fluocinolone acetonide (FA), and some other keywords were commonly studied in this field. In conclusion, the bibliometric analysis provides a comprehensive overview of steroid hotspots and developmental tendencies in the macular edema study. While anti-VEGF therapy is the first-line treatment for DME and RVO-induced macular edema, steroids implant is a valid option for these DME patients not responding to anti-VEGF therapy and non-DME patients with macular edema. Combined therapy with anti-VEGF and steroid agents is vital for future research.
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Affiliation(s)
- Yu Lin
- Research Laboratory of Ophthalmology and Vision Sciences, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China.,Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
| | - Xiang Ren
- Research Laboratory of Ophthalmology and Vision Sciences, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China.,Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
| | - Danian Chen
- Research Laboratory of Ophthalmology and Vision Sciences, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China.,Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
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12
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Wang SK, Cepko CL. Targeting Microglia to Treat Degenerative Eye Diseases. Front Immunol 2022; 13:843558. [PMID: 35251042 PMCID: PMC8891158 DOI: 10.3389/fimmu.2022.843558] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2021] [Accepted: 01/31/2022] [Indexed: 12/29/2022] Open
Abstract
Microglia have been implicated in many degenerative eye disorders, including retinitis pigmentosa, age-related macular degeneration, glaucoma, diabetic retinopathy, uveitis, and retinal detachment. While the exact roles of microglia in these conditions are still being discovered, evidence from animal models suggests that they can modulate the course of disease. In this review, we highlight current strategies to target microglia in the eye and their potential as treatments for both rare and common ocular disorders. These approaches include depleting microglia with chemicals or radiation, reprogramming microglia using homeostatic signals or other small molecules, and inhibiting the downstream effects of microglia such as by blocking cytokine activity or phagocytosis. Finally, we describe areas of future research needed to fully exploit the therapeutic value of microglia in eye diseases.
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Affiliation(s)
- Sean K. Wang
- Department of Ophthalmology, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, United States
| | - Constance L. Cepko
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, United States
- Department of Ophthalmology, Harvard Medical School, Boston, MA, United States
- Howard Hughes Medical Institute, Chevy Chase, MD, United States
- *Correspondence: Constance L. Cepko,
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13
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Markan A, Neupane S, Agrawal R, Gupta V. Newer therapeutic agents for retinal diseases. EXPERT REVIEW OF OPHTHALMOLOGY 2022. [DOI: 10.1080/17469899.2022.2030709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Ashish Markan
- Advanced Eye Centre, Department of Ophthalmology, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Swechya Neupane
- Advanced Eye Centre, Department of Ophthalmology, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Rupesh Agrawal
- Department of Ophthalmology, National Healthcare Group Eye Institute, Tan Tock Sen Hospital, Novena, Singapore
| | - Vishali Gupta
- Advanced Eye Centre, Department of Ophthalmology, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
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14
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Rodríguez ML, Millán I, Ortega ÁL. Cellular targets in diabetic retinopathy therapy. World J Diabetes 2021; 12:1442-1462. [PMID: 34630899 PMCID: PMC8472497 DOI: 10.4239/wjd.v12.i9.1442] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 05/08/2021] [Accepted: 08/03/2021] [Indexed: 02/06/2023] Open
Abstract
Despite the existence of treatment for diabetes, inadequate metabolic control triggers the appearance of chronic complications such as diabetic retinopathy. Diabetic retinopathy is considered a multifactorial disease of complex etiology in which oxidative stress and low chronic inflammation play essential roles. Chronic exposure to hyperglycemia triggers a loss of redox balance that is critical for the appearance of neuronal and vascular damage during the development and progression of the disease. Current therapies for the treatment of diabetic retinopathy are used in advanced stages of the disease and are unable to reverse the retinal damage induced by hyperglycemia. The lack of effective therapies without side effects means there is an urgent need to identify an early action capable of preventing the development of the disease and its pathophysiological consequences in order to avoid loss of vision associated with diabetic retinopathy. Therefore, in this review we propose different therapeutic targets related to the modulation of the redox and inflammatory status that, potentially, can prevent the development and progression of the disease.
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Affiliation(s)
- María Lucía Rodríguez
- Department of Physiology, Faculty of Pharmacy, University of Valencia, Burjassot 46100, Valencia, Spain
| | - Iván Millán
- Neonatal Research Group, Health Research Institute La Fe, Valencia 46026, Valencia, Spain
| | - Ángel Luis Ortega
- Department of Physiology, Faculty of Pharmacy, University of Valencia, Burjassot 46100, Valencia, Spain
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15
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Harsing LG, Szénási G, Zelles T, Köles L. Purinergic-Glycinergic Interaction in Neurodegenerative and Neuroinflammatory Disorders of the Retina. Int J Mol Sci 2021; 22:ijms22126209. [PMID: 34201404 PMCID: PMC8228622 DOI: 10.3390/ijms22126209] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 06/03/2021] [Accepted: 06/04/2021] [Indexed: 12/26/2022] Open
Abstract
Neurodegenerative–neuroinflammatory disorders of the retina seriously hamper human vision. In searching for key factors that contribute to the development of these pathologies, we considered potential interactions among purinergic neuromodulation, glycinergic neurotransmission, and microglia activity in the retina. Energy deprivation at cellular levels is mainly due to impaired blood circulation leading to increased release of ATP and adenosine as well as glutamate and glycine. Interactions between these modulators and neurotransmitters are manifold. First, P2Y purinoceptor agonists facilitate reuptake of glycine by glycine transporter 1, while its inhibitors reduce reverse-mode operation; these events may lower extracellular glycine levels. The consequential changes in extracellular glycine concentration can lead to parallel changes in the activity of NR1/NR2B type NMDA receptors of which glycine is a mandatory agonist, and thereby may reduce neurodegenerative events in the retina. Second, P2Y purinoceptor agonists and glycine transporter 1 inhibitors may indirectly inhibit microglia activity by decreasing neuronal or glial glycine release in energy-compromised retina. These inhibitions may have a role in microglia activation, which is present during development and progression of neurodegenerative disorders such as glaucomatous and diabetic retinopathies and age-related macular degeneration or loss of retinal neurons caused by thromboembolic events. We have hypothesized that glycine transporter 1 inhibitors and P2Y purinoceptor agonists may have therapeutic importance in neurodegenerative–neuroinflammatory disorders of the retina by decreasing NR1/NR2B NMDA receptor activity and production and release of a series of proinflammatory cytokines from microglial cells.
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Affiliation(s)
- Laszlo G. Harsing
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary; (T.Z.); (L.K.)
- Correspondence: ; Tel.: +36-1-210-4416
| | - Gábor Szénási
- Institute of Translational Medicine, Semmelweis University, H-1089 Budapest, Hungary;
| | - Tibor Zelles
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary; (T.Z.); (L.K.)
- Department of Oral Biology, Semmelweis University, H-1089 Budapest, Hungary
| | - László Köles
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary; (T.Z.); (L.K.)
- Department of Oral Biology, Semmelweis University, H-1089 Budapest, Hungary
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16
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Zhao X, Sun R, Luo X, Wang F, Sun X. The Interaction Between Microglia and Macroglia in Glaucoma. Front Neurosci 2021; 15:610788. [PMID: 34121982 PMCID: PMC8193936 DOI: 10.3389/fnins.2021.610788] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Accepted: 04/22/2021] [Indexed: 01/11/2023] Open
Abstract
Glaucoma, a neurodegenerative disease that leads to irreversible vision loss, is characterized by progressive loss of retinal ganglion cells (RGCs) and optic axons. To date, elevated intraocular pressure (IOP) has been recognized as the main phenotypic factor associated with glaucoma. However, some patients with normal IOP also have glaucomatous visual impairment and RGC loss. Unfortunately, the underlying mechanisms behind such cases remain unclear. Recent studies have suggested that retinal glia play significant roles in the initiation and progression of glaucoma. Multiple types of glial cells are activated in glaucoma. Microglia, for example, act as critical mediators that orchestrate the progression of neuroinflammation through pro-inflammatory cytokines. In contrast, macroglia (astrocytes and Müller cells) participate in retinal inflammatory responses as modulators and contribute to neuroprotection through the secretion of neurotrophic factors. Notably, research results have indicated that intricate interactions between microglia and macroglia might provide potential therapeutic targets for the prevention and treatment of glaucoma. In this review, we examine the specific roles of microglia and macroglia in open-angle glaucoma, including glaucoma in animal models, and analyze the interaction between these two cell types. In addition, we discuss potential treatment options based on the relationship between glial cells and neurons.
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Affiliation(s)
- Xiaohuan Zhao
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai General Hospital, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
| | - Rou Sun
- Department of Ophthalmology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xueting Luo
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai General Hospital, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
| | - Feng Wang
- Department of Immunology and Microbiology, Shanghai General Hospital, The Center for Microbiota and Immunological Diseases, Shanghai Institute of Immunology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiaodong Sun
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai General Hospital, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
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17
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Nian S, Lo ACY, Mi Y, Ren K, Yang D. Neurovascular unit in diabetic retinopathy: pathophysiological roles and potential therapeutical targets. EYE AND VISION 2021; 8:15. [PMID: 33931128 PMCID: PMC8088070 DOI: 10.1186/s40662-021-00239-1] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 04/02/2021] [Indexed: 02/06/2023]
Abstract
Diabetic retinopathy (DR), one of the common complications of diabetes, is the leading cause of visual loss in working-age individuals in many industrialized countries. It has been traditionally regarded as a purely microvascular disease in the retina. However, an increasing number of studies have shown that DR is a complex neurovascular disorder that affects not only vascular structure but also neural tissue of the retina. Deterioration of neural retina could precede microvascular abnormalities in the DR, leading to microvascular changes. Furthermore, disruption of interactions among neurons, vascular cells, glia and local immune cells, which collectively form the neurovascular unit, is considered to be associated with the progression of DR early on in the disease. Therefore, it makes sense to develop new therapeutic strategies to prevent or reverse retinal neurodegeneration, neuroinflammation and impaired cell-cell interactions of the neurovascular unit in early stage DR. Here, we present current perspectives on the pathophysiology of DR as a neurovascular disease, especially at the early stage. Potential novel treatments for preventing or reversing neurovascular injuries in DR are discussed as well.
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Affiliation(s)
- Shen Nian
- Department of Pathology, Xi'an Medical University, Xi'an, Shaanxi Province, China.
| | - Amy C Y Lo
- Department of Ophthalmology, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, Hong Kong
| | - Yajing Mi
- Institute of Basic Medicine Science, Xi'an Medical University, Xi'an, Shaanxi Province, China
| | - Kai Ren
- Department of Biochemistry and Molecular Biology, Xi'an Medical University, Xi'an, Shaanxi Province, China
| | - Di Yang
- Department of Ophthalmology, First Affiliated Hospital of Kunming Medical University, Kunming Medical University, Kunming, Yunnan Province, China.
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18
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PPARα Agonist Oral Therapy in Diabetic Retinopathy. Biomedicines 2020; 8:biomedicines8100433. [PMID: 33086679 PMCID: PMC7589723 DOI: 10.3390/biomedicines8100433] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 10/13/2020] [Accepted: 10/15/2020] [Indexed: 12/12/2022] Open
Abstract
Diabetic retinopathy (DR) is an eye condition that develops after chronically poorly-managed diabetes, and is presently the main cause for blindness on a global scale. Current treatments for DR such as laser photocoagulation, topical injection of corticosteroids, intravitreal injection of anti-vascular endothelial growth factor (VEGF) agents and vitreoretinal surgery are only applicable at the late stages of DR and there are possibilities of significant adverse effects. Moreover, the forms of treatment available for DR are highly invasive to the eyes. Safer and more effective pharmacological treatments are required for DR treatment, in particular at an early stage. In this review, we cover recently investigated promising oral pharmacotherapies, the methods of which are safer, easier to use, patient-friendly and pain-free, in clinical studies. We especially focus on peroxisome proliferator-activator receptor alpha (PPARα) agonists in which experimental evidence suggests PPARα activation may be closely related to the attenuation of vascular damages, including lipid-induced toxicity, inflammation, an excess of free radical generation, endothelial dysfunction and angiogenesis. Furthermore, oral administration of selective peroxisome proliferator-activated receptor alpha modulator (SPPARMα) agonists may induce hepatic fibroblast growth factor 21 expression, indirectly resulting in retinal protection in animal studies. Our review will enable more comprehensive approaches for understanding protective roles of PPARα for the prevention of DR development.
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19
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Shahid M. Neuroprotection for Retinal Ganglion Cells. JOURNAL OF EXPLORATORY RESEARCH IN PHARMACOLOGY 2020; 000:1-2. [DOI: 10.14218/jerp.2020.00023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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20
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Wright C, Mazzucco AE, Becker SM, Sieving PA, Tumminia SJ. NEI-Supported Age-Related Macular Degeneration Research: Past, Present, and Future. Transl Vis Sci Technol 2020; 9:49. [PMID: 32832254 PMCID: PMC7414643 DOI: 10.1167/tvst.9.7.49] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 04/08/2020] [Indexed: 12/15/2022] Open
Abstract
Purpose To review past and current National Eye Institute (NEI)–supported age-related macular degeneration (AMD) activities and initiatives and preview upcoming coordinated efforts for studying AMD. Methods We conducted and summarized a portfolio analysis and literature review of NEI intramural and extramural AMD activities. Results The NEI supports a broad range of AMD research, both by individual independent investigators as well as through networks and consortia. The International AMD Genomics Consortium, Age-Related Eye Disease Study, Age-Related Eye Disease Study 2 (AREDS2), and Comparison of AMD Treatments Trial legacy work probed the complex genetics, clinical presentation, and standards of patient care, respectively. The NEI AMD Pathobiology Working Group identified gaps and opportunities for future research efforts. The AMD Ryan Initiative Study and clinical trials testing the efficacies of minocycline to modulate retinal microglia activity and induced pluripotent stem cells–derived retinal pigmented epithelium (RPE) patch implants to rescue photoreceptor cell death are among the future directions for NEI-supported AMD research. Finally, NEI commissioned the creation of AREDS2 participant-derived induced pluripotent stem cell (iPSC) lines linked to their associated genomic and phenotypic datasets. These datasets will also be linked to the data obtained using their associated iPSC-derived cells (RPE, retina, choroid) and made publicly available. Conclusions Investments by NEI for AMD research will continue to provide invaluable resources to investigators committed to addressing this complex blinding disease and other retinal degenerative diseases. Translational Relevance NEI now stands poised to expand the resources available to clinical investigators to uncover disease mechanisms and move experimental therapies into clinical trials.
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Affiliation(s)
- Charles Wright
- Division of Extramural Science Programs, National Eye Institute, Bethesda, MD, USA
| | - Anna E Mazzucco
- Immediate Office of the Director, National Institutes of Health, Bethesda, MD, USA
| | - Steven M Becker
- Office of the Director, National Eye Institute, Bethesda, MD, USA
| | - Paul A Sieving
- Previous Director, National Eye Institute, Bethesda, MD, USA.,Ophthalmology and Vision Science, University of California, Davis, Davis, CA, USA
| | - Santa J Tumminia
- Office of the Director, National Eye Institute, Bethesda, MD, USA
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21
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Eid SA, O'Brien PD, Hinder LM, Hayes JM, Mendelson FE, Zhang H, Narayanan S, Abcouwer SF, Brosius FC, Pennathur S, Savelieff MG, Feldman EL. Differential effects of minocycline on microvascular complications in murine models of type 1 and type 2 diabetes. ACTA ACUST UNITED AC 2020; 7. [PMID: 33868719 PMCID: PMC8048053 DOI: 10.15761/jts.1000431] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Diabetes is a global healthcare problem associated with enormous healthcare and personal costs. Despite glucose lowering agents that control glycaemia, both type 1 (T1D) and type (T2D) diabetes patients often develop microvascular complications that increase morbidity and mortality. Current interventions rely on careful glycemic control and healthy lifestyle choices, but these are ineffective at reversing or completely preventing the major microvascular complications, diabetic peripheral neuropathy (DPN), diabetic retinopathy (DR), and diabetic kidney disease (DKD). Minocycline, a tetracycline antibiotic with anti-inflammatory and anti-apoptotic properties, has been proposed as a protective agent in diabetes. However, there are no reported studies evaluating the therapeutic efficacy of minocycline in T1D and T2D models for all microvascular complications (DPN, DR, and DKD). Therefore, we performed metabolic profiling in streptozotocin-induced T1D and db/db T2D models and compared the efficacy of minocycline in preventing complications to that of insulin and pioglitazone in both models. Minocycline partially ameliorated DR and DKD in T1D and T2D animals, but was less effective than insulin or pioglitazone, and failed to improve DPN in either model. These results suggest that minocycline is unlikely to improve outcomes beyond that achieved with current available therapies in patients with T1D or T2D associated microvascular complications.
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Affiliation(s)
- Stephanie A Eid
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Phillipe D O'Brien
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Lucy M Hinder
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - John M Hayes
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Faye E Mendelson
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Hongyu Zhang
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, 48109, U.S.A
| | - Samanthi Narayanan
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Steven F Abcouwer
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, 48105, U.S.A
| | - Frank C Brosius
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, 48109, U.S.A.,Departments of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, 48109, U.S.A
| | - Subramaniam Pennathur
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, 48109, U.S.A.,Departments of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, 48109, U.S.A
| | - Masha G Savelieff
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Eva L Feldman
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109, USA
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22
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Asadi A, Abdi M, Kouhsari E, Panahi P, Sholeh M, Sadeghifard N, Amiriani T, Ahmadi A, Maleki A, Gholami M. Minocycline, focus on mechanisms of resistance, antibacterial activity, and clinical effectiveness: Back to the future. J Glob Antimicrob Resist 2020; 22:161-174. [PMID: 32061815 DOI: 10.1016/j.jgar.2020.01.022] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 01/17/2020] [Accepted: 01/28/2020] [Indexed: 12/11/2022] Open
Abstract
OBJECTIVES The increasing crisis regarding multidrug-resistant (MDR) and extensively drug-resistant microorganisms leads to appealing therapeutic options. METHODS During the last 30 years, minocycline, a wide-spectrum antimicrobial agent, has been effective against MDR Gram-positive and Gram-negative bacterial infections. As with other tetracyclines, the mechanism of action of minocycline involves attaching to the bacterial 30S ribosomal subunit and preventing protein synthesis. RESULTS This antimicrobial agent has been approved for the treatment of acne vulgaris, some sexually transmitted diseases and rheumatoid arthritis. Although many reports have been published, there remains limited information regarding the prevalence, mechanism of resistance and clinical effectiveness of minocycline. CONCLUSION Thus, we summarize here the currently available data concerning pharmacokinetics and pharmacodynamics, mechanism of action and resistance, antibacterial activity and clinical effectiveness of minocycline.
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Affiliation(s)
- Arezoo Asadi
- Department of Microbiology, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Milad Abdi
- Department of Microbiology, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Ebrahim Kouhsari
- Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam, Iran; Laboratory Sciences Research Center, Golestan University of Medical Sciences, Gorgan, Iran.
| | - Pegah Panahi
- Department of Microbiology, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Mohammad Sholeh
- Department of Microbiology, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Nourkhoda Sadeghifard
- Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam, Iran
| | - Taghi Amiriani
- Golestan Research Center of Gastroenterology and Hepatology, Golestan University of Medical Sciences, Gorgan, Iran
| | - Alireza Ahmadi
- Laboratory Sciences Research Center, Golestan University of Medical Sciences, Gorgan, Iran
| | - Abbas Maleki
- Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam, Iran
| | - Mehrdad Gholami
- Department of Microbiology and Virology, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
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23
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Reichenbach A, Bringmann A. Glia of the human retina. Glia 2019; 68:768-796. [PMID: 31793693 DOI: 10.1002/glia.23727] [Citation(s) in RCA: 152] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 07/16/2019] [Accepted: 07/17/2019] [Indexed: 12/22/2022]
Abstract
The human retina contains three types of glial cells: microglia and two types of macroglia, astrocytes and Müller cells. Macroglia provide homeostatic and metabolic support to photoreceptors and neurons required for neuronal activity. The fovea, the site of the sharpest vision which is astrocyte- and microglia-free, contains two populations of Müller glia: cells which form the Müller cell cone in the foveola and z-shaped Müller cells of the foveal walls. Both populations are characterized by morphological and functional differences. Müller cells of the foveola do not support the activity of photoreceptors and neurons, but provide the structural stability of the foveal tissue and improve the light transmission through the tissue to the photoreceptors. This article gives overviews of the glia of the human retina and the structure and function of both Müller cell types in the fovea, and describes the contributions of astrocytes and Müller cells to the ontogenetic development of the fovea.
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Affiliation(s)
- Andreas Reichenbach
- Paul Flechsig Institute of Brain Research, University of Leipzig, Leipzig, Germany
| | - Andreas Bringmann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
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24
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Spencer BG, Estevez JJ, Liu E, Craig JE, Finnie JW. Pericytes, inflammation, and diabetic retinopathy. Inflammopharmacology 2019; 28:697-709. [PMID: 31612299 DOI: 10.1007/s10787-019-00647-9] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 09/13/2019] [Indexed: 12/11/2022]
Abstract
Diabetic retinopathy (DR) is a frequent complication of diabetes mellitus, and a common cause of vision impairment and blindness in these patients, yet many aspects of its pathogenesis remain unresolved. Furthermore, current treatments are not effective in all patients, are only indicated in advanced disease, and are associated with significant adverse effects. This review describes the microvascular features of DR, and how pericyte depletion and low-grade chronic inflammation contribute to the pathogenesis of this common ophthalmic disorder. Existing, novel and investigational pharmacological strategies aimed at modulating the inflammatory component of DR and ameliorating pericyte loss to potentially improve clinical outcomes for patients with diabetic retinopathy, are discussed.
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Affiliation(s)
- Benjamin G Spencer
- TMOU, Flinders Medical Centre, Southern Adelaide Local Health Network, SA Health, Flinders Drive, Bedford Park, SA, 5042, Australia.
| | - Jose J Estevez
- Flinders Centre for Ophthalmology, Eye and Vision Research, Department of Ophthalmology, Flinders University, Adelaide, Australia
| | - Ebony Liu
- Flinders Centre for Ophthalmology, Eye and Vision Research, Department of Ophthalmology, Flinders University, Adelaide, Australia
| | - Jamie E Craig
- Flinders Centre for Ophthalmology, Eye and Vision Research, Department of Ophthalmology, Flinders University, Adelaide, Australia
| | - John W Finnie
- Discipline of Anatomy and Pathology, Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia
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25
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Coughlin BA, Guha-Niyogi P, Sikorskii A, Glazer LC, Mohr S. Ranibizumab Alters Levels of Intraocular Soluble Cytokine Receptors in Patients with Diabetic Macular Edema. Curr Eye Res 2019; 45:509-520. [DOI: 10.1080/02713683.2019.1665187] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Brandon A. Coughlin
- Department of Physiology, Michigan State University, East Lansing, Michigan, USA
| | - Pratim Guha-Niyogi
- Department of Statistics and Probability, Michigan State University, East Lansing, Michigan, USA
| | - Alla Sikorskii
- Department of Statistics and Probability, Michigan State University, East Lansing, Michigan, USA
- Department of Psychiatry, Michigan State University, East Lansing, Michigan, USA
| | | | - Susanne Mohr
- Department of Physiology, Michigan State University, East Lansing, Michigan, USA
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26
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Rashid K, Akhtar-Schaefer I, Langmann T. Microglia in Retinal Degeneration. Front Immunol 2019; 10:1975. [PMID: 31481963 PMCID: PMC6710350 DOI: 10.3389/fimmu.2019.01975] [Citation(s) in RCA: 200] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Accepted: 08/05/2019] [Indexed: 12/18/2022] Open
Abstract
The retina is a complex tissue with multiple cell layers that are highly ordered. Its sophisticated structure makes it especially sensitive to external or internal perturbations that exceed the homeostatic range. This necessitates the continuous surveillance of the retina for the detection of noxious stimuli. This task is mainly performed by microglia cells, the resident tissue macrophages which confer neuroprotection against transient pathophysiological insults. However, under sustained pathological stimuli, microglial inflammatory responses become dysregulated, often worsening disease pathology. In this review, we provide an overview of recent studies that depict microglial responses in diverse retinal pathologies that have degeneration and chronic immune reactions as key pathophysiological components. We also discuss innovative immunomodulatory therapy strategies that dampen the detrimental immunological responses to improve disease outcome.
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Affiliation(s)
- Khalid Rashid
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Isha Akhtar-Schaefer
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Thomas Langmann
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne, Cologne, Germany
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Akhtar-Schäfer I, Wang L, Krohne TU, Xu H, Langmann T. Modulation of three key innate immune pathways for the most common retinal degenerative diseases. EMBO Mol Med 2019; 10:emmm.201708259. [PMID: 30224384 PMCID: PMC6180304 DOI: 10.15252/emmm.201708259] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
This review highlights the role of three key immune pathways in the pathophysiology of major retinal degenerative diseases including diabetic retinopathy, age‐related macular degeneration, and rare retinal dystrophies. We first discuss the mechanisms how loss of retinal homeostasis evokes an unbalanced retinal immune reaction involving responses of local microglia and recruited macrophages, activity of the alternative complement system, and inflammasome assembly in the retinal pigment epithelium. Presenting these key mechanisms as complementary targets, we specifically emphasize the concept of immunomodulation as potential treatment strategy to prevent or delay vision loss. Promising molecules are ligands for phagocyte receptors, specific inhibitors of complement activation products, and inflammasome inhibitors. We comprehensively summarize the scientific evidence for this strategy from preclinical animal models, human ocular tissue analyses, and clinical trials evolving in the last few years.
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Affiliation(s)
- Isha Akhtar-Schäfer
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Cologne, Germany
| | - Luping Wang
- Department of Ophthalmology, University of Bonn, Bonn, Germany
| | - Tim U Krohne
- Department of Ophthalmology, University of Bonn, Bonn, Germany
| | - Heping Xu
- Centre for Experimental Medicine, The Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry & Biomedical Sciences, Queen's University Belfast, Belfast, UK
| | - Thomas Langmann
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Cologne, Germany .,Center for Molecular Medicine, University of Cologne, Cologne, Germany
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Valent DJ, Wong WT, Chew EY, Cukras CA. Oral Dextromethorphan for the Treatment of Diabetic Macular Edema: Results From a Phase I/II Clinical Study. Transl Vis Sci Technol 2018; 7:24. [PMID: 30584490 PMCID: PMC6300336 DOI: 10.1167/tvst.7.6.24] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 08/18/2018] [Indexed: 12/14/2022] Open
Abstract
Purpose The activation of microglia, the primary innate immune cell resident in the retina, produces inflammatory mediators, which underlie changes in diabetic retinopathy including increased vascular permeability. This study evaluates the safety and efficacy of dextromethorphan, a drug capable of inhibiting microglial activation, in the treatment of diabetic macular edema (DME). Methods A single-center, prospective, open-label phase I/II clinical trial enrolled five participants with macular involving DME who received oral dextromethorphan 60 mg twice daily for 6 months as monotherapy. Main outcome variables included central retinal subfield thickness (CST), best-corrected visual acuity (BCVA), macula sensitivity, and late leakage on fluorescein angiogram (FA). Results The study drug was well tolerated. At the primary end point of 6 months, mean CST decreased by −6.3% ± 6.8% and BCVA increased by +0.6 ± 5.11 (mean ± SEM) letters. Late leakage on FA was scored as improved in four of five study eyes. These findings were not correlated with changes in hemoglobin A1c (HbA1c), creatinine, or blood pressure. Conclusions In this proof-of-concept study, dextromethorphan administration as the primary treatment for DME was associated with decreased vascular leakage, suggesting possible therapeutic effects. Additional studies investigating the modulation of microglial activation is warranted. Translational Relevance These findings highlight microglial modulation as a potentially useful therapeutic strategy in the treatment of diabetic macular edema.
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Affiliation(s)
- David J Valent
- Division of Epidemiology and Clinical Applications, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Wai T Wong
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Emily Y Chew
- Division of Epidemiology and Clinical Applications, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Catherine A Cukras
- Division of Epidemiology and Clinical Applications, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
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Whitehead M, Wickremasinghe S, Osborne A, Van Wijngaarden P, Martin KR. Diabetic retinopathy: a complex pathophysiology requiring novel therapeutic strategies. Expert Opin Biol Ther 2018; 18:1257-1270. [PMID: 30408422 PMCID: PMC6299358 DOI: 10.1080/14712598.2018.1545836] [Citation(s) in RCA: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 11/05/2018] [Indexed: 12/15/2022]
Abstract
INTRODUCTION Diabetic retinopathy (DR) is the leading cause of vision loss in the working age population of the developed world. DR encompasses a complex pathology, and one that is reflected in the variety of currently available treatments, which include laser photocoagulation, glucocorticoids, vitrectomy and agents which neutralize vascular endothelial growth factor (VEGF). Whilst these options demonstrate modest clinical benefits, none is yet to fully attenuate clinical progression or reverse damage to the retina. This has led to an interest in developing novel therapies for the condition, such as mediators of angiopoietin signaling axes, immunosuppressants, nonsteroidal anti-inflammatory drugs (NSAIDs), oxidative stress inhibitors and vitriol viscosity inhibitors. Further, preclinical research suggests that gene therapy treatment for DR could provide significant benefits over existing treatments options. AREAS COVERED Here we review the pathophysiology of DR and provide an overview of currently available treatments. We then outline recent advances made towards improved patient outcomes and highlight the potential of the gene therapy paradigm to revolutionize DR management. EXPERT OPINION Whilst significant progress has been made towards our understanding of DR, further research is required to enable the development of a detailed spatiotemporal model of the disease. In addition, we hope that improvements in our knowledge of the condition facilitate therapeutic innovations that continue to address unmet medical need and improve patient outcomes, with a focus on the development of targeted medicines.
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Affiliation(s)
- Michael Whitehead
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Sanjeewa Wickremasinghe
- Centre for Eye Research Australia, University of Melbourne and Royal Victorian Eye and Ear Hospital, Melbourne, Australia
- Department of Surgery, University of Melbourne, Melbourne, Australia
| | - Andrew Osborne
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Peter Van Wijngaarden
- Centre for Eye Research Australia, University of Melbourne and Royal Victorian Eye and Ear Hospital, Melbourne, Australia
- Department of Surgery, University of Melbourne, Melbourne, Australia
| | - Keith R. Martin
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
- Eye Department, Addenbrooke’s Hospital, Cambridge, UK
- Cambridge NIHR Biomedical Research Centre, Cambridge, UK
- Wellcome Trust – MRC Cambridge Stem Cell Institute, University of Cambridge, Cambridge, UK
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Abstract
Microglia, the primary resident immune cell type, constitute a key population of glia in the retina. Recent evidence indicates that microglia play significant functional roles in the retina at different life stages. During development, retinal microglia regulate neuronal survival by exerting trophic influences and influencing programmed cell death. During adulthood, ramified microglia in the plexiform layers interact closely with synapses to maintain synaptic structure and function that underlie the retina's electrophysiological response to light. Under pathological conditions, retinal microglia participate in potentiating neurodegeneration in diseases such as glaucoma, retinitis pigmentosa, and age-related neurodegeneration by producing proinflammatory neurotoxic cytokines and removing living neurons via phagocytosis. Modulation of pathogenic microglial activation states and effector mechanisms has been linked to neuroprotection in animal models of retinal diseases. These findings have led to the design of early proof-of-concept clinical trials with microglial modulation as a therapeutic strategy.
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Affiliation(s)
- Sean M. Silverman
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, USA;,
| | - Wai T. Wong
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, USA;,
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Rathnasamy G, Foulds WS, Ling EA, Kaur C. Retinal microglia - A key player in healthy and diseased retina. Prog Neurobiol 2018; 173:18-40. [PMID: 29864456 DOI: 10.1016/j.pneurobio.2018.05.006] [Citation(s) in RCA: 127] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 03/09/2018] [Accepted: 05/29/2018] [Indexed: 01/04/2023]
Abstract
Microglia, the resident immune cells of the brain and retina, are constantly engaged in the surveillance of their surrounding neural tissue. During embryonic development they infiltrate the retinal tissues and participate in the phagocytosis of redundant neurons. The contribution of microglia in maintaining the purposeful and functional histo-architecture of the adult retina is indispensable. Within the retinal microenvironment, robust microglial activation is elicited by subtle changes caused by extrinsic and intrinsic factors. When there is a disturbance in the cell-cell communication between microglia and other retinal cells, for example in retinal injury, the activated microglia can manifest actions that can be detrimental. This is evidenced by activated microglia secreting inflammatory mediators that can further aggravate the retinal injury. Microglial activation as a harbinger of a variety of retinal diseases is well documented by many studies. In addition, a change in the microglial phenotype which may be associated with aging, may predispose the retina to age-related diseases. In light of the above, the focus of this review is to highlight the role played by microglia in the healthy and diseased retina, based on findings of our own work and from that of others.
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Affiliation(s)
- Gurugirijha Rathnasamy
- Department of Anatomy, Yong Loo Lin School of Medicine, Blk MD10, 4 Medical Drive, National University of Singapore, 117594, Singapore; Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin, Madison, WI, 53706, United States
| | - Wallace S Foulds
- Singapore Eye Research Institute Level 6, The Academia, Discovery Tower, 20 College Road, 169856, Singapore; University of Glasgow, Glasgow, Scotland, G12 8QQ, United Kingdom
| | - Eng-Ang Ling
- Department of Anatomy, Yong Loo Lin School of Medicine, Blk MD10, 4 Medical Drive, National University of Singapore, 117594, Singapore
| | - Charanjit Kaur
- Department of Anatomy, Yong Loo Lin School of Medicine, Blk MD10, 4 Medical Drive, National University of Singapore, 117594, Singapore.
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Rübsam A, Parikh S, Fort PE. Role of Inflammation in Diabetic Retinopathy. Int J Mol Sci 2018; 19:ijms19040942. [PMID: 29565290 PMCID: PMC5979417 DOI: 10.3390/ijms19040942] [Citation(s) in RCA: 438] [Impact Index Per Article: 73.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 03/09/2018] [Accepted: 03/17/2018] [Indexed: 02/07/2023] Open
Abstract
Diabetic retinopathy is a common complication of diabetes and remains the leading cause of blindness among the working-age population. For decades, diabetic retinopathy was considered only a microvascular complication, but the retinal microvasculature is intimately associated with and governed by neurons and glia, which are affected even prior to clinically detectable vascular lesions. While progress has been made to improve the vascular alterations, there is still no treatment to counteract the early neuro-glial perturbations in diabetic retinopathy. Diabetes is a complex metabolic disorder, characterized by chronic hyperglycemia along with dyslipidemia, hypoinsulinemia and hypertension. Increasing evidence points to inflammation as one key player in diabetes-associated retinal perturbations, however, the exact underlying molecular mechanisms are not yet fully understood. Interlinked molecular pathways, such as oxidative stress, formation of advanced glycation end-products and increased expression of vascular endothelial growth factor have received a lot of attention as they all contribute to the inflammatory response. In the current review, we focus on the involvement of inflammation in the pathophysiology of diabetic retinopathy with special emphasis on the functional relationships between glial cells and neurons. Finally, we summarize recent advances using novel targets to inhibit inflammation in diabetic retinopathy.
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Affiliation(s)
- Anne Rübsam
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105, USA.
| | - Sonia Parikh
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105, USA.
| | - Patrice E Fort
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105, USA.
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48105, USA.
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The Role of Microglia in Diabetic Retinopathy: Inflammation, Microvasculature Defects and Neurodegeneration. Int J Mol Sci 2018; 19:ijms19010110. [PMID: 29301251 PMCID: PMC5796059 DOI: 10.3390/ijms19010110] [Citation(s) in RCA: 233] [Impact Index Per Article: 38.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 12/23/2017] [Accepted: 12/25/2017] [Indexed: 12/15/2022] Open
Abstract
Diabetic retinopathy is a common complication of diabetes mellitus, which appears in one third of all diabetic patients and is a prominent cause of vision loss. First discovered as a microvascular disease, intensive research in the field identified inflammation and neurodegeneration to be part of diabetic retinopathy. Microglia, the resident monocytes of the retina, are activated due to a complex interplay between the different cell types of the retina and diverse pathological pathways. The trigger for developing diabetic retinopathy is diabetes-induced hyperglycemia, accompanied by leukostasis and vascular leakages. Transcriptional changes in activated microglia, mediated via the nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) and extracellular signal–regulated kinase (ERK) signaling pathways, results in release of various pro-inflammatory mediators, including cytokines, chemokines, caspases and glutamate. Activated microglia additionally increased proliferation and migration. Among other consequences, these changes in microglia severely affected retinal neurons, causing increased apoptosis and subsequent thinning of the nerve fiber layer, resulting in visual loss. New potential therapeutics need to interfere with these diabetic complications even before changes in the retina are diagnosed, to prevent neuronal apoptosis and blindness in patients.
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Landfried B, Grimm C. Neuroprotektion geschädigter Photorezeptoren. MED GENET-BERLIN 2017. [DOI: 10.1007/s11825-017-0130-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Zusammenfassung
Der Schutz der Sehzellen durch Neuroprotektion ist ein vielversprechender Ansatz, der bei vielen degenerativen Netzhauterkrankungen entweder als Mono- oder Kombinationstherapie zum Einsatz kommen könnte. Viele neuroprotektive Substanzen wurden im Tiermodell identifiziert und erfolgreich getestet. Einige dieser Substanzen wurden auch bereits in klinischen Versuchen am Patienten untersucht, allerdings mit unterschiedlichem Erfolg. Diverse Versuchsansätze werden derzeit überprüft.
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Affiliation(s)
- Britta Landfried
- Aff1 0000 0004 0478 9977 grid.412004.3 Augenklinik Universitätsspital Zürich Zürich Schweiz
- Aff4 0000 0004 1937 0650 grid.7400.3 Labor für Zellbiologie der Netzhaut, Augenklinik Universität Zürich Wagistrasse 14 8952 Schlieren Schweiz
| | - Christian Grimm
- Aff1 0000 0004 0478 9977 grid.412004.3 Augenklinik Universitätsspital Zürich Zürich Schweiz
- Aff2 0000 0004 1937 0650 grid.7400.3 Zentrum für integrative Humanphysiologie (ZIHP) Universität Zürich Zürich Schweiz
- Aff3 0000 0004 1937 0650 grid.7400.3 Zentrum für Neurowissenschaften Zürich (ZNZ) Universität Zürich Zürich Schweiz
- Aff4 0000 0004 1937 0650 grid.7400.3 Labor für Zellbiologie der Netzhaut, Augenklinik Universität Zürich Wagistrasse 14 8952 Schlieren Schweiz
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Karlstetter M, Dannhausen K, Langmann T. Mikroglia und Immuntherapien bei degenerativen Netzhauterkrankungen. MED GENET-BERLIN 2017. [DOI: 10.1007/s11825-017-0132-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Zusammenfassung
Bei allen bisher im Detail untersuchten erblichen Netzhautdegenerationen liegt eine dem Erkrankungsverlauf abträgliche chronische Aktivierung des angeborenen Immunsystems zugrunde. Vor allem residente Mikrogliazellen der Netzhaut und verschiedene Proteine des löslichen Komplementsystems tragen zu einer Schädigung von Photorezeptoren und retinalem Pigmentepithel bei. Sowohl spezifische Zielstrukturen auf reaktiven Immunzellen als auch fehlregulierte lösliche Immunmodulatoren bieten neue Ansatzpunkte für Therapien, um das Überleben der Netzhaut trotz genetischer Prädisposition zur Degeneration zu fördern. Dieser Beitrag gibt Einblick in die wesentlichen Regulationsmechanismen der Netzhautimmunologie, diskutiert die mögliche Verwendung immunologischer Biomarker für die Netzhautdiagnostik und zeigt immunmodulierende Therapieansätze durch Biologika und endogene Botenstoffe auf.
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Affiliation(s)
- Marcus Karlstetter
- Aff1 0000 0000 8852 305X grid.411097.a Lehrstuhl für Experimentelle Immunologie des Auges, Zentrum für Augenheilkunde Uniklinik Köln Joseph-Stelzmann-Str. 9 50931 Köln Deutschland
| | - Katharina Dannhausen
- Aff1 0000 0000 8852 305X grid.411097.a Lehrstuhl für Experimentelle Immunologie des Auges, Zentrum für Augenheilkunde Uniklinik Köln Joseph-Stelzmann-Str. 9 50931 Köln Deutschland
| | - Thomas Langmann
- Aff1 0000 0000 8852 305X grid.411097.a Lehrstuhl für Experimentelle Immunologie des Auges, Zentrum für Augenheilkunde Uniklinik Köln Joseph-Stelzmann-Str. 9 50931 Köln Deutschland
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Amorim D, Puga S, Bragança R, Braga A, Pertovaara A, Almeida A, Pinto-Ribeiro F. Minocycline reduces mechanical allodynia and depressive-like behaviour in type-1 diabetes mellitus in the rat. Behav Brain Res 2017; 327:1-10. [DOI: 10.1016/j.bbr.2017.03.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 02/24/2017] [Accepted: 03/02/2017] [Indexed: 12/29/2022]
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Tamoxifen Provides Structural and Functional Rescue in Murine Models of Photoreceptor Degeneration. J Neurosci 2017; 37:3294-3310. [PMID: 28235894 DOI: 10.1523/jneurosci.2717-16.2017] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Revised: 02/05/2017] [Accepted: 02/08/2017] [Indexed: 12/19/2022] Open
Abstract
Photoreceptor degeneration is a cause of irreversible vision loss in incurable blinding retinal diseases including retinitis pigmentosa (RP) and atrophic age-related macular degeneration. We found in two separate mouse models of photoreceptor degeneration that tamoxifen, a selective estrogen receptor modulator and a drug previously linked with retinal toxicity, paradoxically provided potent neuroprotective effects. In a light-induced degeneration model, tamoxifen prevented onset of photoreceptor apoptosis and atrophy and maintained near-normal levels of electroretinographic responses. Rescue effects were correlated with decreased microglial activation and inflammatory cytokine production in the retina in vivo and a reduction of microglia-mediated toxicity to photoreceptors in vitro, indicating a microglia-mediated mechanism of rescue. Tamoxifen also rescued degeneration in a genetic (Pde6brd10) model of RP, significantly improving retinal structure, electrophysiological responses, and visual behavior. These prominent neuroprotective effects warrant the consideration of tamoxifen as a drug suitable for being repurposed to treat photoreceptor degenerative disease.SIGNIFICANCE STATEMENT Photoreceptor degeneration is a cause of irreversible blindness in a number of retinal diseases such as retinitis pigmentosa (RP) and atrophic age-related macular degeneration. Tamoxifen, a selective estrogen receptor modulator approved for the treatment of breast cancer and previously linked to a low incidence of retinal toxicity, was unexpectedly found to exert marked protective effects against photoreceptor degeneration. Structural and functional protective effects were found for an acute model of light-induced photoreceptor injury and for a genetic model for RP. The mechanism of protection involved the modulation of microglial activation and the production of inflammatory cytokines, highlighting the role of inflammatory mechanisms in photoreceptor degeneration. Tamoxifen may be suitable for clinical study as a potential treatment for diseases involving photoreceptor degeneration.
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Stabilization of endogenous Nrf2 by minocycline protects against Nlrp3-inflammasome induced diabetic nephropathy. Sci Rep 2016; 6:34228. [PMID: 27721446 PMCID: PMC5056367 DOI: 10.1038/srep34228] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 09/07/2016] [Indexed: 02/06/2023] Open
Abstract
While a plethora of studies support a therapeutic benefit of Nrf2 activation and ROS inhibition in diabetic nephropathy (dNP), the Nrf2 activator bardoxolone failed in clinical studies in type 2 diabetic patients due to cardiovascular side effects. Hence, alternative approaches to target Nrf2 are required. Intriguingly, the tetracycline antibiotic minocycline, which has been in clinical use for decades, has been shown to convey anti-inflammatory effects in diabetic patients and nephroprotection in rodent models of dNP. However, the mechanism underlying the nephroprotection remains unknown. Here we show that minocycline protects against dNP in mouse models of type 1 and type 2 diabetes, while caspase -3,-6,-7,-8 and -10 inhibition is insufficient, indicating a function of minocycline independent of apoptosis inhibition. Minocycline stabilizes endogenous Nrf2 in kidneys of db/db mice, thus dampening ROS-induced inflammasome activation in the kidney. Indeed, minocycline exerts antioxidant effects in vitro and in vivo, reducing glomerular markers of oxidative stress. Minocycline reduces ubiquitination of the redox-sensitive transcription factor Nrf2 and increases its protein levels. Accordingly, minocycline mediated Nlrp3 inflammasome inhibition and amelioration of dNP are abolished in diabetic Nrf2−/− mice. Taken together, we uncover a new function of minocycline, which stabilizes the redox-sensitive transcription factor Nrf2, thus protecting from dNP.
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Bolinger MT, Antonetti DA. Moving Past Anti-VEGF: Novel Therapies for Treating Diabetic Retinopathy. Int J Mol Sci 2016; 17:E1498. [PMID: 27618014 PMCID: PMC5037775 DOI: 10.3390/ijms17091498] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 08/22/2016] [Accepted: 08/30/2016] [Indexed: 12/25/2022] Open
Abstract
Diabetic retinopathy is the leading cause of blindness in working age adults, and is projected to be a significant future health concern due to the rising incidence of diabetes. The recent advent of anti-vascular endothelial growth factor (VEGF) antibodies has revolutionized the treatment of diabetic retinopathy but a significant subset of patients fail to respond to treatment. Accumulating evidence indicates that inflammatory cytokines and chemokines other than VEGF may contribute to the disease process. The current review examines the presence of non-VEGF cytokines in the eyes of patients with diabetic retinopathy and highlights mechanistic pathways in relevant animal models. Finally, novel drug targets including components of the kinin-kallikrein system and emerging treatments such as anti-HPTP (human protein tyrosine phosphatase) β antibodies are discussed. Recognition of non-VEGF contributions to disease pathogenesis may lead to novel therapeutics to enhance existing treatments for patients who do not respond to anti-VEGF therapies.
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Affiliation(s)
- Mark T Bolinger
- Departments of Ophthalmology and Visual Sciences, Kellogg Eye Center, and Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48105, USA.
| | - David A Antonetti
- Departments of Ophthalmology and Visual Sciences, Kellogg Eye Center, and Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48105, USA.
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Stewart MW, Flynn HW, Schwartz SG, Scott IU. Extended duration strategies for the pharmacologic treatment of diabetic retinopathy: current status and future prospects. Expert Opin Drug Deliv 2016; 13:1277-87. [DOI: 10.1080/17425247.2016.1198771] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
| | - Harry W. Flynn
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Stephen G. Schwartz
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Naples, FL, USA
| | - Ingrid U. Scott
- Penn State Hershey Eye Center, Penn State College of Medicine, Hershey, PA, USA
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Shah AP, Shen JI, Wang Y, Tong L, Pak Y, Andalibi A, LaPage JA, Adler SG. Effects of Minocycline on Urine Albumin, Interleukin-6, and Osteoprotegerin in Patients with Diabetic Nephropathy: A Randomized Controlled Pilot Trial. PLoS One 2016; 11:e0152357. [PMID: 27019421 PMCID: PMC4809491 DOI: 10.1371/journal.pone.0152357] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 03/11/2016] [Indexed: 01/19/2023] Open
Abstract
Background We tested minocycline as an anti-proteinuric adjunct to renin-angiotensin-aldosterone system inhibitors (RAASi) in diabetic nephropathy (DN) and measured urinary biomarkers to evaluate minocycline’s biological effects. Methods Design: Prospective, single center, randomized, placebo-controlled, intention-to-treat pilot trial. Inclusion. Type 2 diabetes/DN; Baseline creatinine clearance > 30 mL/min; proteinuria ≥ 1.0 g/day; Age ≥30 years; BP <150/95 mm Hg; intolerant of/at maximum RAASi dose. Protocol. 3-wk screening; Baseline randomization; Urine and blood measures at months 1, 2, 4, and Month 6 study completion. Urine interleukin-6 (IL-6) and osteoprotegerin were measured in a subset. Primary outcome. Natural log of urine protein/creatinine (ln U P:Cr) ratio at Month 6 vs Baseline. Results 30 patients completed the study. The 15% decline in U P: Cr in minocycline patients (6 month P:Cr ÷ Baseline P:Cr, 0.85 vs. 0.92) was not significant (p = 0.27). Creatinine clearance did not differ in the 2 groups. Urine IL-6:Cr (p = 0.03) and osteoprotegerin/Cr (p = 0.046) decrements were significant. Minocycline modified the relationship between urine IL-6 and proteinuria, suggesting a protective biological effect. Conclusions Although the decline in U P:Cr in minocycline patients was not statistically significant, the significant differences in urine IL-6 and osteoprotegerin suggest that minocycline may confer cytoprotection in patients with DN, providing a rationale for further study. Trial Registration Clinicaltrials.gov NCT01779089
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Affiliation(s)
- Anuja P. Shah
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, 1124 West Carson Street, Torrance, CA, 90509, United States of America
| | - Jenny I. Shen
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, 1124 West Carson Street, Torrance, CA, 90509, United States of America
| | - Ying Wang
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, 1124 West Carson Street, Torrance, CA, 90509, United States of America
| | - Lili Tong
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, 1124 West Carson Street, Torrance, CA, 90509, United States of America
| | - Youngju Pak
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, 1124 West Carson Street, Torrance, CA, 90509, United States of America
| | - Ali Andalibi
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, 1124 West Carson Street, Torrance, CA, 90509, United States of America
| | - Janine A. LaPage
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, 1124 West Carson Street, Torrance, CA, 90509, United States of America
| | - Sharon G. Adler
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, 1124 West Carson Street, Torrance, CA, 90509, United States of America
- * E-mail:
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Silverman SM, Kim BJ, Howell GR, Miller J, John SWM, Wordinger RJ, Clark AF. C1q propagates microglial activation and neurodegeneration in the visual axis following retinal ischemia/reperfusion injury. Mol Neurodegener 2016; 11:24. [PMID: 27008854 PMCID: PMC4806521 DOI: 10.1186/s13024-016-0089-0] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 03/18/2016] [Indexed: 12/03/2022] Open
Abstract
Background C1q represents the initiating protein of the classical complement cascade, however recent findings indicate pathway independent roles such as developmental pruning of retinal ganglion cell (RGC) axons. Furthermore, chronic neuroinflammation, including increased expression of C1q and activation of microglia and astrocytes, appears to be a common finding among many neurodegenerative disease models. Here we compare the effects of a retinal ischemia/reperfusion (I/R) injury on glial activation and neurodegeneration in wild type (WT) and C1qa-deficient mice in the retina and superior colliculus (SC). Retinal I/R was induced in mice through elevation of intraocular pressure to 120 mmHg for 60 min followed by reperfusion. Glial cell activation and population changes were assessed using immunofluorescence. Neuroprotection was determined using histological measurements of retinal layer thickness, RGC counts, and visual function by flash electroretinography (ERG). Results Retinal I/R injury significantly upregulated C1q expression in the retina as early as 72 h and within 7 days in the superficial SC, and was sustained as long as 28 days. Accompanying increased C1q expression was activation of microglia and astrocytes as well as a significantly increased glial population density observed in the retina and SC. Microglial activation and changes in density were completely ablated in C1qa-deficient mice, interestingly however there was no effect on astrocytes. Furthermore, loss of C1qa significantly rescued I/R-induced loss of RGCs and protected against retinal layer thinning in comparison to WT mice. ERG assessment revealed early preservation of b-wave amplitude deficits from retinal I/R injury due to C1qa-deficiency that was lost by day 28. Conclusions Our results for the first time demonstrate the spatiotemporal changes in the neuroinflammatory response following retinal I/R injury at both local and distal sites of injury. In addition, we have shown a role for C1q as a primary mediator of microglial activation and pathological damage. This suggests developmental mechanisms of C1q may be re-engaged during injury response, modulation of which may be beneficial for neuroprotection. Electronic supplementary material The online version of this article (doi:10.1186/s13024-016-0089-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sean M Silverman
- North Texas Eye Research Institute, University of North Texas Health Science Center, CBH-441, 3500 Camp Bowie Boulevard, Fort Worth, TX, 76107, USA
| | - Byung-Jin Kim
- North Texas Eye Research Institute, University of North Texas Health Science Center, CBH-441, 3500 Camp Bowie Boulevard, Fort Worth, TX, 76107, USA
| | | | | | - Simon W M John
- The Jackson Laboratory, Bar Harbor, 04609, ME, USA.,Howard Hughes Medical Institute, Bar Harbor, ME, 04609, USA
| | - Robert J Wordinger
- North Texas Eye Research Institute, University of North Texas Health Science Center, CBH-441, 3500 Camp Bowie Boulevard, Fort Worth, TX, 76107, USA
| | - Abbot F Clark
- North Texas Eye Research Institute, University of North Texas Health Science Center, CBH-441, 3500 Camp Bowie Boulevard, Fort Worth, TX, 76107, USA.
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Kohno H, Koso H, Okano K, Sundermeier TR, Saito S, Watanabe S, Tsuneoka H, Sakai T. Expression pattern of Ccr2 and Cx3cr1 in inherited retinal degeneration. J Neuroinflammation 2015; 12:188. [PMID: 26458944 PMCID: PMC4603985 DOI: 10.1186/s12974-015-0408-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 10/02/2015] [Indexed: 12/27/2022] Open
Abstract
Background Though accumulating evidence suggests that microglia, resident macrophages in the retina, and bone marrow-derived macrophages can cause retinal inflammation which accelerates photoreceptor cell death, the details of how these cells are activated during retinal degeneration (RD) remain uncertain. Therefore, it is important to clarify which cells play a dominant role in fueling retinal inflammation. However, distinguishing between microglia and macrophages is difficult using conventional techniques such as cell markers (e.g., Iba-1). Recently, two mouse models for visualizing chemokine receptors were established, Cx3cr1GFP/GFP and Ccr2RFP/RFP mice. As Cx3cr1 is expressed in microglia and Ccr2 is reportedly expressed in activated macrophages, these mice have the potential to distinguish microglia and macrophages, yielding novel information about the activation of these inflammatory cells and their individual roles in retinal inflammation. Methods In this study, c-mer proto-oncogene tyrosine kinase (Mertk)−/− mice, which show photoreceptor cell death due to defective retinal pigment epithelium phagocytosis, were employed as an animal model of RD. Mertk−/−Cx3cr1GFP/+Ccr2RFP/+ mice were established by breeding Mertk−/−, Cx3cr1GFP/GFP, and Ccr2RFP/RFP mice. The retinal morphology and pattern of inflammatory cell activation and invasion of Mertk−/−Cx3cr1GFP/+Ccr2RFP/+ mice were evaluated using retina and retinal pigment epithelium (RPE) flat mounts, retinal sections, and flow cytometry. Results Four-week-old Mertk−/−Cx3cr1GFP/+Ccr2RFP/+ mice showed Cx3cr1-GFP-positive microglia in the inner retina. Cx3cr1-GFP and Ccr2-RFP dual positive activated microglia were observed in the outer retina and subretinal space of 6- and 8-week-old animals. Ccr2-RFP single positive bone marrow-derived macrophages were observed to migrate into the retina of Mertk−/−Cx3cr1GFP/+Ccr2RFP/+ mice. These invading cells were still observed in the subretinal space in 18-week-old animals. Conclusions Cx3cr1-GFP-positive microglia and Ccr2-RFP-positive macrophages were distinguishable in the retinas of Mertk−/−Cx3cr1GFP/+Ccr2RFP/+ mice. In addition, Ccr2 expression in Cx3cr1 positive microglia is a feature of microglial activation in RD. Mertk−/−Cx3cr1GFP/+Ccr2RFP/+ mice enabled observation of microglial activation over time during RD and may be useful for developing inflammation-targeted treatment strategies for RD in the future.
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Affiliation(s)
- Hideo Kohno
- Department of Ophthalmology, The Jikei University School of Medicine, 105-8461, Tokyo, Japan. .,Tokyu Hospital, 145-0062, Tokyo, Japan.
| | - Hideto Koso
- Division of Molecular and Developmental Biology, The Institute of Medical Science, The University of Tokyo, 108-8639, Tokyo, Japan
| | - Kiichiro Okano
- Department of Ophthalmology, The Jikei University School of Medicine, 105-8461, Tokyo, Japan
| | - Thomas R Sundermeier
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Saburo Saito
- Department of Molecular Immunology, The Jikei University School of Medicine, 105-8461, Tokyo, Japan
| | - Sumiko Watanabe
- Division of Molecular and Developmental Biology, The Institute of Medical Science, The University of Tokyo, 108-8639, Tokyo, Japan
| | - Hiroshi Tsuneoka
- Department of Ophthalmology, The Jikei University School of Medicine, 105-8461, Tokyo, Japan
| | - Tsutomu Sakai
- Department of Ophthalmology, The Jikei University School of Medicine, 105-8461, Tokyo, Japan.
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Falavarjani KG, Pourhabibi A, Aghdam KA, Hosseini SB, Modarres M, Pazouki A, Khanamiri HN. Determination of the toxicity of intravitreal minocycline in rabbit eyes. Cutan Ocul Toxicol 2015; 35:233-6. [DOI: 10.3109/15569527.2015.1081604] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Abstract
Diabetic retinopathy, an oculardisease, is governed by systemic as well as local ocular factors. These include primarily chronic levels of blood glucose. Individuals with chronically elevated blood glucose levels have substantially more, and more severe, retinopathy than those with lower blood glucose levels. The relationship of blood glucose to retinopathy is continuous, with no threshold although individuals with hemoglobin A1c levels (a measure of chronic glycemia) <6.5%, generally develop little or no retinopathy. Blood pressure levels have been claimed to influence retinopathy development and progression, but multiple controlled clinical trials of antihypertensive agents in diabetic subjects have produced only weak evidence of benefit from blood pressure lowering on the incidence and progression of diabetic retinopathy. Elevated blood lipids seem to play a role in the progression of retinopathy, and two trials of fenofibrate, a lipid-lowering agent that has not proved effective in preventing cardiovascular disease, have shown benefit in preventing retinopathy progression. The mechanism of this effect may not, however, be directly related to the reduction in blood lipids. Finally, there is strong, but only circumstantial, evidence for a genetic or epigenetic influence on the pathogenesis of diabetic retinopathy. Despite the power of large-scale epidemiologic studies and modern molecular biological and computational techniques, the gene or genes, which predispose or protect against the development and progression of diabetic retinopathy remain elusive.
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Affiliation(s)
- Robert N Frank
- Department of Ophthalmology, Kresge Eye Institute, Wayne State University School of Medicine, Detroit, MI, USA
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46
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Adalimumab Reduces Photoreceptor Cell Death in A Mouse Model of Retinal Degeneration. Sci Rep 2015; 5:11764. [PMID: 26170250 PMCID: PMC4501000 DOI: 10.1038/srep11764] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 06/02/2015] [Indexed: 12/29/2022] Open
Abstract
Growing evidence suggests that inflammation is involved in the progression of retinitis pigmentosa (RP) both in patients and in animal models. The aim of this study was to investigate the effect of Adalimumab, a monoclonal anti-TNFα antibody, on retinal degeneration in a murine model of human autosomal recessive RP, the rd10 mice at postnatal day (P) 18. In our housing conditions, rd10 retinas were seriously damaged at P18. Adalimumab reduced photoreceptor cell death, as determined by scoring the number of TUNEL-positive cells. In addition, nuclear poly (ADP) ribose (PAR) content, an indirect measure of PAR polymerase (PARP) activity, was also reduced after treatment. The blockade of TNFα ameliorated reactive gliosis, as visualized by decreased GFAP and IBA1 immunolabelling (Müller cell and microglial markers, respectively) and decreased up-regulation of TNFα gene expression. Adalimumab also improved antioxidant response by restoring total antioxidant capacity and superoxide dismutase activity. Finally, we observed that Adalimumab normalized energetic and metabolic pattern in rd10 mouse retinas. Our study suggests that the TNFα blockade could be a successful therapeutic approach to increase photoreceptor survival during the progression of RP. Further studies are needed to characterize its effect along the progression of the disease.
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Wu Y, Chen Y, Wu Q, Jia L, Du X. Minocycline inhibits PARP‑1 expression and decreases apoptosis in diabetic retinopathy. Mol Med Rep 2015; 12:4887-94. [PMID: 26165350 PMCID: PMC4581760 DOI: 10.3892/mmr.2015.4064] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 06/03/2015] [Indexed: 01/30/2023] Open
Abstract
The present study aimed to investigate the mechanism underlying the effects of minocycline on diabetic retinopathy-associated cellular apoptosis. A total of 40 Sprague Dawley (SD) rats were used as a diabetic retinopathy model following injection with streptozotocin. Among the 34 rats in which the diabetes model was successfully established, 24 rats were divided into two experimental groups: I and II (T1 and T2, respectively), and orally administered with various doses of minocycline. The remaining 10 rats served as the diabetic retinopathy control group. An additional group of 10 healthy SD rats with comparable weight served as normal controls. The rats in T1 and T2 groups were treated daily for eight consecutive weeks with minocycline at a dose of 2.5 mg/kg and 5 mg/kg, respectively. The mRNA expression levels of poly (ADP-ribose) polymerase-1 (PARP-1) were subsequently measured by reverse transcription-quantitative polymerase chain reaction, and the protein expression levels of poly-ADP-ribose were measured by western blot analysis and immunohistochemistry. Retinal morphology was observed following hematoxylin and eosin staining, and retinal cell apoptosis was measured by terminal deoxynucleotidyl transferase dUTP nick end labeling and caspase-3 activity assays. The amplitudes of the electroretinogram (ERG) b-wave and oscillary potentials (OPs) were measured using visual electrophysiology, and compared among the four groups. The results of the present study demonstrated that in the diabetic rats, retinal PARP-1 gene expression was markedly upregulated, the number of apoptotic cells and the activity levels of caspase-3 were increased, and the amplitude of the ERG b-wave and the OPs were markedly lower as compared with the normal rats. Following treatment with minocycline, the abnormal expression of PARP-1 in the retina was inhibited, and cellular apoptosis was decreased. In conclusion, the results of the present study suggest that PARP-1 is involved in the development of diabetic retinopathy, and minocycline is able to inhibit PARP-1 expression and decrease cellular apoptosis, suggesting that minocycline may prove to be a promising drug for the treatment of diabetic retinopathy.
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Affiliation(s)
- Ying Wu
- Department of Ultrasound, Shanghai First People's Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200080, P.R. China
| | - Yongdong Chen
- Department of Ophthalmology, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai 200233, P.R. China
| | - Qiang Wu
- Department of Ophthalmology, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai 200233, P.R. China
| | - Lili Jia
- Department of Ophthalmology, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai 200233, P.R. China
| | - Xinhua Du
- Department of Ophthalmology, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai 200233, P.R. China
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Das A, McGuire PG, Rangasamy S. Diabetic Macular Edema: Pathophysiology and Novel Therapeutic Targets. Ophthalmology 2015; 122:1375-94. [PMID: 25935789 DOI: 10.1016/j.ophtha.2015.03.024] [Citation(s) in RCA: 345] [Impact Index Per Article: 38.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 02/23/2015] [Accepted: 03/17/2015] [Indexed: 12/15/2022] Open
Abstract
Diabetic macular edema (DME) is the major cause of vision loss in diabetic persons. Alteration of the blood-retinal barrier is the hallmark of this disease, characterized by pericyte loss and endothelial cell-cell junction breakdown. Recent animal and clinical studies strongly indicate that DME is an inflammatory disease. Multiple cytokines and chemokines are involved in the pathogenesis of DME, with multiple cellular involvement affecting the neurovascular unit. With the introduction of anti-vascular endothelial growth factor (VEGF) agents, the treatment of DME has been revolutionized, and the indication for laser therapy has been limited. However, the response to anti-VEGF drugs in DME is not as robust as in proliferative diabetic retinopathy, and many patients with DME do not show complete resolution of fluid despite multiple intravitreal injections. Potential novel therapies targeting molecules other than VEGF and using new drug-delivery systems currently are being developed and evaluated in clinical trials.
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Affiliation(s)
- Arup Das
- Department of Surgery/Ophthalmology, University of New Mexico School of Medicine, Albuquerque, New Mexico; New Mexico VA Health Care System, Albuquerque, New Mexico.
| | - Paul G McGuire
- Department of Cell Biology and Physiology, University of New Mexico School of Medicine, Albuquerque, New Mexico
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Zaidi FH, Ansari E. New treatments for diabetic macular edema. World J Ophthalmol 2015; 5:45-54. [DOI: 10.5318/wjo.v5.i2.45] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Revised: 02/10/2015] [Accepted: 04/07/2015] [Indexed: 02/06/2023] Open
Abstract
This work comprehensively reviews the latest treatment options for diabetic macular edema (DME) used in its management and presents further work on the topic. Diabetic retinopathy is an important and increasingly prevalent cause of preventable blindness worldwide. To meet this increasing burden there has recently been a proliferation of pharmacological therapies being used in clinical practice. A variety of medical treatment options now exist for DME. These include non-steroidal anti-inflammatory drugs such as nepafenac, as well as intravitreal steroids like triamcinolone (kenalog). Long-term results up to 7 years after commencing treatment are presented for triamcinolone. Studies are reviewed on the use of dexamethasone (ozurdex) and fluocinolone (Retisert and Iluvien implants) including the FAME studies. A variety of anti-vascular endothelial growth factor (anti-VEGF) agents used in DME are considered in detail including ranibizumab (lucentis) and the RESTORE, RIDE, RISE and Diabetic Retinopathy Clinical Research Network (DRCR.net) studies. Bevacizumab (avastin) and pegaptinib (macugen) are also considered. The use of aflibercept (eylea) is reviewed including the significance of the DA VINCI, VISTA-DME, VIVID-DME and the DRCR.net studies which have recently suggested potentially greater efficacy when treating DME for aflibercept in patients with more severely reduced visual acuity at baseline. Evidence for the anti-VEGF agent bevasiranib is also considered. Studies of anti-tumour necrosis factor agents like infliximab are reviewed. So are studies of other agents targeting inflammation including minocycline, rapamycin (sirolimus) and protein kinase C inhibitors such as midostaurin and ruboxistaurin. The protein kinase C β inhibitor Diabetic Macular Edema Study is considered. Other agents which have been suggested for DME are discussed including cyclo-oxygenase-2 inhibitors like celecoxib, phospholipase A2 inhibitors, recombinant erythropoietin, and monoclonal anti-interleukin antibodies such as canakinumab. The management of DME in a variety of clinical scenarios is also discussed - in newly diagnosed DME, refractory DME including after macular laser, and postoperatively after intraocular surgery. Results of long-term intravitreal triamcinolone for DME administered up to seven years after commencing treatment are considered in the context of the niche roles available for such agents in modern management of DME. This is alongside more widely used treatments available to the practitioner such as anti-VEGF agents like aflibercept (Eylea) and ranibizumab (Lucentis) which at present are the mainstay of pharmacological treatment of DME.
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50
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Li L, Eter N, Heiduschka P. The microglia in healthy and diseased retina. Exp Eye Res 2015; 136:116-30. [PMID: 25952657 DOI: 10.1016/j.exer.2015.04.020] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 04/28/2015] [Accepted: 04/29/2015] [Indexed: 12/25/2022]
Abstract
The microglia are the immune cells of the central nervous system and, also the retina. They fulfil several tasks of surveillance in the healthy retina. In case of an injury or disease, microglia become activated and tries to repair the damage. However, in a lot of cases it does not work, and microglia deteriorate the situation by releasing toxic and pro-inflammatory compounds. Moreover, they further promote degenerative processes by attacking and phagocytosing damaged neurones and photoreceptors that otherwise would possibly have the chance to survive. Such deleterious action of the microglia has been observed in degeneration of retinal ganglion cells and photoreceptors, and it takes place in hereditary diseases, infections as well as in case of traumatic or light injuries. Therefore, a number of attempts has been undertaken so far to inhibit the microglia, with varying success. The task remains to study behaviour of the microglia and their interaction with other retinal cell populations in more detail with respect to released factors and expressed receptors including the time points of the corresponding events. The goal has to be to find a better balance between helpful and detrimental actions of the microglia.
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Affiliation(s)
- Lu Li
- University of Münster Medical School, Department of Ophthalmology, Domagkstr. 15, D-48149 Münster, Germany
| | - Nicole Eter
- University of Münster Medical School, Department of Ophthalmology, Domagkstr. 15, D-48149 Münster, Germany
| | - Peter Heiduschka
- University of Münster Medical School, Department of Ophthalmology, Domagkstr. 15, D-48149 Münster, Germany.
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